ITEM J5: ANALYSIS OF CONSTRUCTION CONDITIONS (TR-55)

GERAGHTYtf MILLER,INC. fl R 3 I | 6 0 I

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flR3l 1602

RUNOFF CURVE; NUMBER COMPUTATION. - version 2.00

roject. .: Bridgestone/Firestone ' " User: JAM Date: 12-09-97: Cecil . "..-..'. "' " State: MD " Checked: ___ Date: ______

itle: Woodlawn Landfill, Construction Conditionsrea : 1 ' . . . _ . . . . . . .

. '. Hydrologic Soil Group'COVER DESCRIPTION ' . ". '::' A " B C D

Acres (CN) '

JLLY DEVELOPED URBAN AREAS {Veg-:Estab.~)~ - - - - . - -pen space (Lawns,parks etc.)• Poor-condition; grass coyer < 50% ' - _.........'.... - 4.8(86)

3tal Area (by Hydrologic Soil Group) • 4.B

JBARSA: 1 TOTAL DRAINAGE AREA: 4.8 Acres ' WEIGHTED CURVE NUMBER: 86

f l R 3 i 1603

RUNOFF CURVE NUMBER COMPUTATION Version 2.00

5roject : Bridgestone/Firestone User: JAM - Date: 12-09-97\ty i Cecil State: MD Checked: Date: ___

Woodlawn Landfill, Construction Conditions'ubarea : 2

Hydrologic Soil GroucCOVER DESCRIPTION A B C " D

Acres (CN)

TJLLY DEVELOPED URBAN AREAS (Veg Estab.)'pen space (Lawns, parks etc.)Poor condition; grass cover < 50% - - 6.9(86)

'otal Area (by Hydrologic Soil Group) 6.9

UBA&EA: 2 TOTAL DRAINAGE AREA: 6.9 Acres .WEIGHTED CURVE NUMBER: 86

3R3! 160(4

RUNOFF CURVE NUMBER COMPUTATION

Project. : B.ridgestone7Fifestpne • User: JAM Date: 12-0-9-97" " ity : .Cecil.. . ,.,„,... ... . -,-X:-^ -state :- MD . Checked: ___ \ .Date: ______

-itle: Woodlawn Landfill, Construction -Conditionsarea : 3 • ." "

Hydrologic Soil Group 'COVER -DESCRIPTION " ' A B - C D

. Acres (CN)

DEVELOPED URBAN AREAS (Veg Estab. }Jpen space (Lawns, parks etc.)Poor condition; grass cover < 50% ' • - - 6. 6 (86)

"otal Area (by Hydro logic "Soil. "Group) 6.6

"UBAREA: 3 • TOTAL DRAINAGE AREA: 6.6' Acres " ' -WEIGHTED CURVE NUMBER: 86

1605

TIME OF CONCENTRATION AND TRAVEL TIME Version 2.00

?roject : Bridgestone/Firestone User: JAM ' Date: 12-09-97ity : Cecil State: MD Checked: Date:citle: Woodlawn Landfill,

rlow Type 2 yearrain

sheet 3 . 3shallow Concent 'd)pen Channel

"low Type 2 yearrain

Sheet 3 , 3shallow Concent 'dShallow Concent 'd)pen Channel

1

5- "-*i Channeli Channel

'low Type 2 yearrain

:heet 3.3"hallow Concent 'd)pen Channel

Length(ft)

50250800

Length(ft)

50350320100

100850

Length(ft)

50400450

Constru<

—— Sub;Slope .(ft/ft)

.08

.08

.02

—— Sub;Slope(ft/ft)

.12

.05

.04

.025

.02

.025

f"*« *L*---- SUD.Si one(ft/ft)

,06,12.04

stion Coric

area #1 -Surfacecode

bu

area #2 -Surfacecode

buu

area S3 -Surfacecode

bu

litions

n Area(sq/ft)

.05 8Time of

2 ---------*•

n Area(sq/ft)

.05 8Time of

.05 8

.05 8

3 .- ————— .n Area

(sq/ft)

.05 8Time of

Wp(ft)

9

Velocity(ft/sec)

Concentration = .0

"Wp(ft)

9

Velocity(ft/sec)

Concentration » 0

99

«Time(hr)

0.0220.0150.057.09*

Time(hr)

0.0190.0270.0280.006.08*

0.0070 . 0 Jfll

Travel Time = 0.0 H

Wp(ft)

Velocity(ft"/ sec)

Time- Chr)

. 0.0250.020

.9 0.023Concentration « 0.07*

—- Sheet Flow Surface Codes ---A Smooth Surface F Grass, Dense --- Shallow ConcentratedB Fallow (No Res.) G Grass, Burmuda --- Surface CodesC Cultivated < 20 % Res. H Woods, Light P PavedD Cultivated > 20 % Res. I Woods, Dense U UnpavedE Grass-Range, Short J Range, Natural

- Generated for use by TABULAR method " - - .'

.AR3I 1606

TABULAR KYDROGRAPH METHOD Version. 2.00

Project : Bri-dgestone/Firestone •_ _ _ User: JAM Date: 12-09-97~ --nty : Cecil"" ""...;"-".;;: ..:. ..:s~tate: "MD" ' ""Checked:""___ Date : .______

•citle: Woodlawn Landfill, Construction Conditions

:al watershed area-: . 0-029 -sq mi . Rainfall type: II Frequency: 10 years__ — ___ — _,_ _ —— — —,______ subareas -----------------------_-._1 ... 2 3

.\rea(sq mi) 0.01* 0. 01* . . 0..01*Rainfall (in) ."5.1 5.1 .. 5.1Curve number 86*.. . . 8.6.*. -. . 86*Runoff {'in) 3 .56 ' 3,56 ' 3 .56 "" " "Tc (hrs) 0.09* 0.08* 0.07*

(Used) 0.10 • 0.10 0.10 . .TimeToOUtlet "0.06* 0.00 0.00 . . . .

(Used) .0.10 0.00 0.00 " :la/P - - ,0.. 06 . 0.06 ' 0706

(Used) 0.10. "Q.l.Q " O.TO ."

Time Total -------———-—Subarea Contribution to Total -Flow (cfs) -----------(hr) Flow.... ...1 —-——2 3 ....

11.0 3 . . .-.-1 1 . . 1 . . .11.3" . 3 - ' 1 " .'•-• 1 . . '1. ' , . . " .11.6 5 ' l ." 2 " 2 . " "11.9. 29 - 4 - 13 -"--.12 : .12.0 - 5 6 - 7 2 5 _ 2 4 - _ . . . ' • _

I ' 70 23P 24. ' -23 , . , '_," / _t3 35." ..... .15" ——— 8 ' "8 D' w --. - Y7^

12.4 21 .. ...10 ~ ----:~6\ S . '' .,12.5 •• 16 -;.-,._6-——•-—5 .5 -12 .-6 -.12 "4 ---"4 4. • .'. . . tZ'f r-V»'12.7 9 - 3 ::"- -.: ---3———'"- 3- -..-.: - .-::- • .-. -r .:12-. 8 - 9 - - 3 ..:. . .;3' '•••" :"-3 -"^- "' -..:.• *T...-t~13 .0 .7 2 ' 3 2 •' • '13.2 ..... ...6 "' :2 -. •:' 2..' ..::.-2" _'_:::.:. _:_._:rrr- -- —13.4 .5 -1 : -2 - 2 = '".-.' :"

13. S " ". '5'.". :. "1.. _..;,....2____ .2.. . . ...13-. 8 .S.. , .1 . - -3. .._...._ 2 _ _:_._ . .___ ____.14.0 3 "i l .• ' .1.. . .... . ": .....-: :14.3 .. .3 - - - a : -.._!. ... ..'1 ' :.:j;:..._.:._...._-;..::,.:._:::14.6 3 1 ' " 1 '-- ;-!"-• - - "- - --——r-15.0' ' '3 . 1 "~. - 1. • - - - - - I - ' •:-.-."- . ;/.-...-:,. _::15.5 3 '. 1 - - t -- - -x - - — ----- ----- --,— •16:o . 3 l . . -......!.„_•: ::M . ...:.....:. n::_' ;;• -

16.5 3 .- 1 1 .- - I' . . - ' - - .'.. '17.0 3 1- . " --1. ' • • 1 ' ------17.5 3 . -.. 1-:_.;- .1' ' •••.•"!- •;. -.- • - - - - - • •18.0 2 0 1 1

1 2 0 1 ' - ' 10 0 0 .. ". -.0 . . . . . .0 . 0 . . 0 0 . . . . . . . . . . . .

.0- - 0 . '0 --.. --0. ----0. . . ... _.....

f l R 3 l !607

P - Peak Flow * - value(s) provided from TR-S5 system routines

A R 3 I 1 6 0 8

SEDCAD+ RIPRAP CHANNEL'DESIGN

riprap inflow - Woodlawn

, ' INPUT VALUES: - '

Shape - . TRAPEZOIDALDischarge 47.00 cfsSlope . .. . • "v 15.00 %Sideslopes (L and R) 5.00:1 . 5.00:1Bottom Width 8.00 feetFreeboard .5 ft

'RESULTS :Steep Slope Design."- Simons/OSM Method

Depth . 0.41 ftwith Freeboard -- 0.91 ft

Top Width - , - - 12.12 ftwith. Freeboard 17.12 ft

Velocity' . 11.35 fpsCross Sectional -Area 4.14 sq ft.Hydraulic Radius . 0.34 ftManning's',n__ .. . .... .,.-0..p38Froude Number " . . 3.42Dmax -_. i.--—_ -__ - „ lr.25.0 ft (15 00 in)

' TD Q' " " ~"~' ' . '"" '""irooq.'ft (12".cro~~iit>D10 0.333~~ff (4.00 in)

flR3i1609

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flR3l 16(3

Appendix J-6

Landfill Gas Calculations

GERAGHTY6?MILLER,INC. flR.3_I I 6

LANDFILL GAS CALCULATIONSWOODLAWN BiPmGESTONE/FlRESTONE

Objective: .I)etermine_me volume of waste deposited in the landfill based on the depth of• waste, landfiiled area, and average compacted waste density.

Landfilled waste thickness ~ 20 Feet1

Area ofLaridfilied Waste - 20.5 acres "

Total Volume of Waste '-=20.5 acres (1L££M) (20 Feet) = 17,859,600-cf_ __ acre

In cubic yards"(CY) = (17,859,600 cf)'( J_iL") = 6.61,470 CY '27 cf

-1 - -————— ' ' ' - —- Jfi OIH<! 4-51 Q?4- P MSIn-place waste volume = (17.S59,600CF) (±2±i2!i) (ZZififll} (-S. -) =217,916 Mg^^ cf Ibs. . ^

-waste deposited equal over 1960-1978 (majority)'-extended deposition by minimal amount to profile 30 yrs beyond closure date (1978)J

G:\PRJCtS'\BF\CAP90:\Appendics\caIcuI.doc

1 HLA Phase I Hydrogeolocial Investigative Report2 Normal compacted waste average waste'density =26.9 lb_s_.../cf (Rer7 Table 7.1,Integrated Waste Management Engineering Principles and.Management Practices).3 Range 22.6-31.1.U/cf for .normal compacted

AR3! 1 6 1 5GERAGHTY<S"MILLER,rNC

Landfill Gas Emissions Calculations

Landfill gas emissions from the Woodlawn Landfill were calculated to determine whether

an active or passive landfill gas management system is required for the site. The final standardsand guidelines for air emissions from municipal solid waste landfills established a regulatorylimit of 50 megagrams per year (Mg/yr) for nonmethane organic compounds (NMOC) (USEPA,

1995). New and existing landfills with emissions that equal or exceeding 50 Mg/yr are required

to design and operate an active gas collection system and a control device that reduces NMOC in

the collected gas by 98 weight-percent using best demonstrated technology. A three tier system

is utilized to determine whether installation of a gas collection system is required. In the firsttier, Teir 1, default values for the methane generation rate constant, methane generation potential,and NMOC concentration are combined with the landfill age and waste acceptance data tocalculate emission rate of NMOCs from the landfill. If the 50 Mg/yr limit is exceeded, Tier 2calculations are performed and sampling must be conducted to collect site-specific data on

NMOC concentrations at the site. The default values for methane generation rate constant andmethane generation potential are still incorporated into the Tier 2 calculations. If the 50 Mgtyr

limit is exceeded again, additional sampling is conducted to determine site-specific values for

methane generation rate constant and methane generation potential. Default values are not

utilized in Tier 3 calculations. Landfills with emissions greater than 50 Mg/yr based on Tier 3

calculation results are required to install a collection and control system for landfill gas

emissions.

A landfill air emissions estimation model, which was developed for the USEPA Office of

Research and Development and Office of Air Quality Planning and Standards was utilized to

perform Tier 1 calculations. The estimation model is based on the Scholl Canyon Gas GenerationModel, which was used in the development of Clean Air Act regulations for landfills. The

Scholl Canyon Model is a first order decay equation that uses site-specific characteristics for

estimating gas generation rate. These characteristics include in-place waste volume, designcapacity, year facility began accepting waste, and concentrations of methane, NMOCs, and air

toxics. Default values for methane generation rate constant (k)> methane generation potential

AR3! 1 6 1 6

(LJ, arid NMOC- concentration, that were defined in the final standards and guidelines, were

utilized as input parameters for the model (USEPA, 1995). These values were determined from

data collected at existing municipal sofid. waste landfills. The k value is equal to 0.05 per year,L0 is 170 cubic meters per megagram (m5/Mg), and NMOC- concentration is 4,000 parts permillion by volume (ppmv).

The percent methane and concentrations of toxic air contaminants were estimated .basedon the analytical data from the soil gas survey conducted at the site by Harding Lawson and

Associates in November 1995, The volatile organic compounds (VOCs) detected hi the landfillgas included trichloroethene, 1,1,1-trichloroethane, tetrachloroethene, vinyl chloride, and total

volatile hydrocarbons. Three (3) of the VOCs, trichloroethene, tetrachloroethene, and vinyl

chloride, are incorporated into the model as air toxics. The highest concentrations of theseconstituents and methane are utilized to develop a worst-case scenario for a conservative

approach The.percent methane concentration_is calculated to be approximately 59 percent and

carbon dioxide is 41 percent. The concentration of trichloroethene, tetrachloroethene, and vinyl

chloride are 1.0 ppmv, 0.005 ppmv, and 0.02 ppmv, respectively.

The iri-place waste volume was calculated based on an average fill depth of 18 feet over

the entire landfill area of 22 acres. The design capacity is equal to the in-place waste volume of

210,475 Mg. The average waste acceptance rate" was based on the total in-place waste volume ,

divided by the total life of the landfill since records were not available on waste placement. The

operating time period of the landfill, was from _1960__to 197_8J_ )proximately 18 years. In order todetermine whether a trend exists for the production of landfill gas at the site, the operating life of

the landfill was extended by 32 years; therefore, the closure year is established as 2010 instead ofthe actual closure year of 1978. A majority of the waste was placed by 1978 to mimic actual sitecharacteristics for landfill gas production and minute quantities of 0.05 to 1.0 Mg.were added

each year thereafter until the year 2010. The model then predicts the landfill gas generation rate

for the total operating period of the landfill plus ten years.

A R 3 I 1 6 1 7

With the model parameters defined above, the maximum emission rate for NMOC, which

occurred in 1978, is 29.4 Mg/yr. The estimated NMOC generation rate is less than the regulatorylimit of 50 Mg/year, therefore, an active landfill gas collection and control system is not requiredfor the Woodlawn landfill. The highest emission rate for methane and NMOC from the landfillhas already occurred and based on the model, a downward trend is apparent in the generation of

methane and NMOC at the site from the peak in me year 1978 to the year 2020. Landfill gasemissions from the Woodlawn Landfill will steadily decrease as the landfill continues to age anddecomposition of waste is completed.

flR3l 16(8

Supplemental Landfill Gas Calculations

ARCADIS GERAGHTYSMILLER: .-.« R 3 M 6 I 9

From Appendix 4C: Spacing Passive Horizontal Gas Collection Pipes,Washington State Department of Ecology: Minimum Functional Standards for Solid WasteHandling (WAS 173-304-460),

Control of methane gas migration to below dangerous levels should be the goal of any gas controlsystem.** Flow of landfill gas through the landfill is by diffusion or convection. **While diffusioncan be an important element in lateral migration of methane, its effect is minimal where naturallyoccurring pressures arc high within the landfill or when an induced exhaust system is used toincrease the landfill pressure gradient" (Moore 1979, Schumacher 1983). Darcy's Law has beenused to characterize the Sow of gas through the refuse (Findikakis and Leckie 1979). UsingDarcy's equation and the assumption that as methane is produced it is simultaneously removed byconvective mechanisms, the following mathematical expressions were derived:

Darcy's Equation:q = KWU/s-w.)*.-?,)/!,) (4G-1)

where: q » gas flow per unit width (fl /hr)

K s refuse permeability (ft/hr)

nij = depth of saturated gas flow (ft)

s.w. » specific weight of landfill gas (Ibf/ft3)

PI = atmospheric pressure (Ibf/ft2)

P? »• landfill gas pressure (Ibf/ft2)

L = flow length (ft)

The total flow out of a given wicEth of refuse is:

Q-K*mi'w*(l/s.w.)*((Pa/PiyQ) (4G-2)

where Q * gas flow (frVhr),

w » width of flow (ft).

Rearranging terms and isolating flow length on the left:

L - K* m,**(l/s.w.)*(( P:/Pi)/Q)

Assuming gas flow is equal to gas production, the following equation applies:

ARCAD1SGERAGHTY&MSLLER

Q = R*(L*w*rn2)*D/(S760) . (4G-4)

where: . . R = gas production rate (ftVyr-Ibm),

m2..= . ."depth of refuse (ft)

D = refuse density (Ibm/ft3) " . . " / -'

8760 = -time conversion (hr/yr) .... . . -

Substituting Equation 4G-4-into Equation 4G-3 and combining flow length terms on the left:

L: = (K*(m,/mz)*(l/s.w.)*(P2-P,)*(8760))/R*D -

Because gas~ will flow to a trench from both directions .within the landfill, the spacing of trenches

will be twice the gas- flow length or ------ ' . . " . . " : ' " ' " . .

S = 2(L) '-

where: - S = " trench spacing (ft) "

Darcy's equation Has been used to describe the flow of gas.in several landfill gas models.However, the equation applies only to laminar flow, not to turjbulent flow (Schumacher, 1983). Inmost systems, especially in a passive system without an induced pressure gradient, it has beenshown that flow is indeed-laminar.

.4G.4 -Application

A passive system p'p'efates \vithout artificially induced.pressure gradients, such as a motor blowerunit to create a negative pressure (vacuum) in extraction wells. Historically, passive ventingsystems have been designed primarily on judgment as to vent spacing and size. There is no welldefined and accepted method in the literature that allots vent pipes to.be. spaced based on sitespecific conditions. The equations prese_ntejd. above_were. developed to calculate the required •spacing of gas vent pipes given site specific conditions ""and a chosen maximum landfill gaspressure. "Typical landfill parameters cited in several literature sources.were substituted into theequations. These'include the following: .. . ; . . . _ ; .

AnrAnic A R 3 I 1621ARCADIS GERAGHTY&MILLER

JUN-a2-98 13*41 FROM.ARCADIS GERAGHTY & MILLER 10=2157526873 PAGE 2/3

O*

•§ms-

Ssi

l S15ill

622

Parameter- . ._,...,«=.,.,.,- -..-Value.. ,„ ..,.. .... .- , .ReferenceRefuse permeability 7.44x10-3. ft/hr . (intrinsic perm. = 11.034 darcys)

Fungaroli and Steiner, 1979

Depth ratio (m,/m2) 1.0 assumed for shallow landfills

Specific weight " : 7.89 x 10-2 Ibtfft3 Schumacher, 1983

Gas pressure (P.) , 15.67 ibffft2 " Findikakis and Leckie, 1979

Gas production rate (R) 0..04 tf/yr-ib. Schumacher, 1983

Refuse density . 37 lorn/ft3 Tchobanoglous, et al., 1977

The graph shown" in Figure 4G. 1 shows the required pipe spacing'versus maximum landfill gaspressure. The curve was derived by.inseiting the parameter values listed above in Equation (4G-5). The calculation worksheets included as Table 4G.1. Following is an example of how thisequation could be used for a shallow, landfill. •

If typical landfill gas pressure (16 psf) are not to be exceeded, a pipe spacing of approximately 330feet is required. . The maximum _flow. distance that methane must travel to reach either a collectionpipe or the edge of the: landfill, where.it.can be collected in a perimeter trench, is less than 165 feet.Vertical risers, connected to the vent piping via tee .couplings, could be used to vent the gas throughthe final cover. The risers would incorporate a flare to bum the gases and thereby eliminatepotential odor problems. ' - . . -

Woodlawn Landfill: • .

System must; .. ...- -•- —* --- ----- --- •--—:---— ,.V.""""TControl methane to below lower explosive limit (5% v/v) at property boundary; ;Control methane to below 100 ppm v/v in structures (no structures; not applicable)Control any other^as_cQnstituents as measured ac property boundary to below ARARs.

Landfill parameter values for the Woodlawn site are shown below. The parameters are literaturevalues unless otherwise indicated: - - - ~ -- - - -

ADrAHIC rt ' 31 1623ARCADIS GERAGHTY&MILLER.

Appendix J-7

Slope Stability Interface Friction Calculations

AnrAmc ! 162*1ARCADIS GERAGHTY& MILLER . .

:r.a <r-tJT-v- —— ..L .J-*I . i t. tt-wttf/-v __<i &$*,( v^t j>____ . Date f.*?//-*? . . . ,'OfAGHT,d^ MILLER. IV +o de-.+rr**jL*j*- v$ke<* .0* Qy JsfW. . . . . . Chkd

^nvtriinmtnl and fflfraitriJi-rurf T a 1(1 S*& & A l\.ftJ Jrtt-lt t -.K

5 he«cieouj cc.mca.--/ '

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c •"- •-•"" '"" flR3l 1625

* MILLER. INC.•mtnt -ind InfrttiriiiTtire

ffR3l1626

Failure Envelope for Shear Box Test

60 95 ' 135Cohesion (psf)

627

* * ********** GeoSlope , ********** Version 5.10 ********** ****** ** (c)1992 by GEOCOMP Corp, Concord, MA ****** ** Licensed to Geraghty & Miller " **** '

Problem Title : WoodlawnDescription : Shear Strength Stability Analysis

Remarks :

***** INPUT DATA *****

Profile Boundaries

Number of Boundaries : 16Number of Top Boundaries : 4 . . . . _.. _... . _.._..

Boundary X-Left Y-Left X-Right Y-Right . Soil TypeNo. (ft) (ft) (ft) , (ft) Below Bnd

1 200.00 58-00 24.6.0.0 63-30 22 246.00 63.30 369.00 .94.00 23 369.00 94.00 - 40.3.00 10.0.00 24 408.00 10.0.00 611.00.. . '108:00 25 253 -00 63.00 369 -00 .. 92 ..00 . 26 369.00 92.00 408.00 98.00 27 408.00 98.00 611.00 'laS-jOO. 28 253.00 62.80 369.00 .91.80 29 369.00 91.80 408.00 97.80 210 408.00 97.8-0 611.00 105 80.. 211 253.00 62.60 369.00 91.60 212 369.00 .91 60 . 408,00.. ... . 97 ..60., . 213 408.00 97.60 611.00 105.60 . 214 253.00 60,60 36~9.QO 8.9.60 115 369.00 89,60 408.00 95.. 60 116 408.00 95.60 611.00 103.60 1

Soil Parameters • -

Number of Soil Types : 2

Soil Total Saturated Cohesion Friction Pore Pressure Piez.Type Unit Wt. Unit Wt. Intercept Angle Pressure Constant SurfaceNo. (pcf) (pcf) Cpsf) (deg) Param. (psf) No.

1 80.0 80.0 0.0 . 35.0 . 0.0.0 0.0 1 .2 115.0 120.0 135.0 0.0 0.00 . a.0 , .1

A R 3 I 1 6 2 8

Piezome.tric7.Surf aces"

Number o£. Surf aces ":."."/i"."; ~',~-:*Unit -Weight of .Water/: 6.2.40 pcf

Piezometric Surface-No. 5 1Number .of Coordinate'"Points" ;~g"'

• Point . ..-X-Water..- ---i - Kb".; : .:-... (ft) " (ft)

1 - - 200.00 - 56.502 246.00 61 ..803 369.00 , 92.504 408.00 95.505 • "" " 611-.OQ" ' "/"106.50

Data for Generating Rankine Block. Surfaces

Number -of- .trial- Surf aces 7/5 o" " "" " "Number of Boxes : 3 -

Segment Lerigth, ft .: 5,0.0 ft

Box. - X-LeJt / /.-Y-"Left ' ' - • • ' X-Right ' :'.' Y-Right HeightNO. - jTEtir .:- .:" "(ft) . ' •"""••" (ft) ' "(ft) • (ft)1 2.53.007.-,.r;Tr-62,80 " "/ " 257'. 66".' "." \ "~' S3 ,80 " 4.002 369"'.00 ':. .-9i.OO. "^ .373" ..00 ' 92.00 4.003" .- -'40.a.00 -• 97.00' . 412.00 . 98.00 4\00

Critical Surfaces

SafetyNo. _ Factor

2 I3 . 1.5414 1.. 5515 1-5566 " i."6T7:7 1.626

/5R3I 1629

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A R 3 I 1632

APPENDIX K h

EXCAVATION AND DISPOSAL OF TRANSFER STATION DRAIN FIELD SOILS

|] D O j (COOGERAGHTY<S? MILLER,INC. n I I 0 J J

APPENDIX KExcavation and Disposal of Transfer Station Drain Field Soils

According to the Section 5.2,5 of the ROD, 13 subsurface and 3 surface soil samples weretaken from the drain field area and mercury concentrations up to 3.9 mg/kg were detected.Data provided in the ERM report indicate that 13 subsurface samples and one surface samplewere obtained for laboratory analysis of mercury. According to ERM, reported mercuryconcentrations exceeded the cleanup level of 1 mg/kg in one location, surface sample SS-2(1.2 mg/kg). None of the subsurface samples analyzed were reported by ERM as exceedingthe cleanup level of 1 mg/kg, specified in Section 7.3 of the ROD.

Additional investigation was conducted by HLA in 1995 .during the predesign investigation.The objectives of pre-design investigation activities in the drain field area are:

• To evaluate the presence and extent of mercury above 1 mg/kg reported by EPA in thedrain field soils

To estimate the volume of contaminated soils to be removed

To evaluate characteristics of soil from the drain field area for disposal purposes

Review of the mercury analyses of soil samples collected from the drain field soil borings(December 1995 Monthly Progress Report) indicates that mercury concentrations exceed theROD-required cleanup concentration of 1 milligram per kilogram only in surface samplescollected south of the drain field. Mercury concentrations in soil samples from within thedrainfield do not exceed this concentration.

Based on these data, an area of approximately 20 feet x 40 feet x 6 indies deep will beexcavated to remove soils that may contain mercury concentrations that exceed the ROD-required cleanup concentration of 1 milligram per kilogram. The excavated soils will bedeposited into lined roll-oSs.

The existing health and safety plan and appropriate personal protective equipment will beused to perform all work associated with this task. A Jerome Meter will be used to fieldscreen mercury vapors during the excavation.

Clean, compactable fill material will be delivered to the site and placed in the excavation. Thearea will men be seeded and mulched. Upon completion, the roll-off* will be secured and lefton-site pending analysis. Representative composite samples will be collected from thecontainers and laboratory-tested for Resource Conservation and Recovery Act (RCRA) wastecharacteristics. Specific analyses to be performed are described in the FSP and QAPP.

If the composite samples do not exhibit RCRA waste characteristics, soils removed from thedrain field will be disposed in the landfill in areas to be capped. If the samples exhibit RCRAwaste characteristics, the waste materials will be disposed offeite in accordance with

GERAGHTYtf MILLER,INC. H n O l_ j 6 3 U

CERCLA 121(d)(3), the CERCLA Off-Site Policy directive (EPA, 1987a), and MarylandHazardous Waste Regulation (COMAR Title 26:13). For all shipments of 10 cubic yards ormore, written notification will be provided to environmental officials of the receiving state andthe EPA Remedial Project Manager (RPM).

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APPENDIX L

CALCULAIHEON OF THE"FLUX OF OXYGEN INTO Tffi; WOODLAWN LANDFILL

flR3i 1637GERAGHTY# MILLER,INC.

APPENDIX L

Calculation of the Flux of Oxygen into the Woodlawn Landfill

Oxygen is transported in the Woodlawn Landfill through three pathways: precipitationrecharge, influx of groundwater from upgradient sources, and gaseous diffusion from theatmosphere through the soil surface. The quantity of oxygen transported along each of thesepathways is quantified below.

Recharge

As documented in Section 2 of this report approximately 5,214,000 gallons of waterinfiltrates into the landfill. This value was computed using the calibrated groundwater flowmodel and is" equivalent to a uniform infiltration rate of 9."4 in/yr into the waste. Assumingthat the average temperature of the precipitation is 20°C, the saturated dissolved oxygenconcentration is 9,2 mg/L Hie annual mass loading of oxygen to the water table throughgroundwaier recharge is computed as follows:

O2 -400.3/65 .h,(, r

iGroundwater

Oxygen is transport into the groundwater beneath the site from lateral inflow ofupgradient groundwater. The calibrated groundwater flow model was used to quantify thelateral groundwater flow under existing and capped conditions. Under existing conditions,there is approximately 175,400 gallons of water per year flowing laterally into thegroundwater beneath the landfill. If the dissolved oxygen levels in off-site groundwater areequal to those in natural rainfall (saturation), then the maximum quantity of oxygen flowinginto the landfill from off-site is 13.5 pounds per year. Under capped conditions, thegroundwater levels beneath the site will decline due to the decrease in precipitation recharge.This decline in water levels will increase the quantity of off-site groundwater flowing beneaththe site on an annual basis to 591,000 gallons. If the dissolved oxygen levels in off-sitegroundwater are equal to those in natural rainfall (saturation), then the maximum quantity ofoxygen flowing into the landfill from off-site will be 45.4 pounds per year if the site is capped.

Atmospheric Diffusion

Oxygen is transported into the vadose zone from the atmosphere. As summarized in"The Narwe and Properties of Soils "

4R3IT638GERAGHTY# MILLER,INC.

M the exchange of gases between the soil and the atmosphere ... is facilitated by twomechanisms: mass flow and diffusioa Mass flow of air, which is due to pressuredifferences between the atmosphere and the soil air, is less important than diffusion indetermining"the total exchange that occurs. It is enhanced, however, by fluctuations insoil moisture content As water moves into the soil during a rain ... air will be forcedout Likewise, when soil water is lost by evaporation from the surface or is taken upby plants, air is drawn into the soil.. Mass flow is also modified slightly by otherfactors such as temperature, barometric pressure, and wind movement

Most,of the gaseous interchange in soils occurs by diffusion."

Brady shows that the oxygen diffusion rate (ODR) is a function of depth and the oxygen levelat the soil surface, m addition, the rate declines asymptotically from approximately 80x10"8g/cm2/min at the soil surface, to 5x1 O 8 g/cmz/min below me bottom of the root zone.Therefore, the roinimum annual mass loading of oxygen through the soil and into the waste inplace is computed to be

^ ' *8 g 1440min 365day . (2.54)2cm2 144 in2 43,560fr20,-=5;dO ——~——-.x -- —x '"" .x-——~——-x—-T—x —————cm -min day year . in" " ft acre

=23401bs/year/acre :.lOOOg r Teg

This quantity of oxygen will not flow through the soil if the landfill is covered with atraditional landfill cover design consisting of either compacted clay or a geosynthetic.

Reference

Brady, Nyle C., 1992. The Nature and Properties of Soils, Tenth Edition, MacMillanPublishing Company, New York, New York.

G:\pocE\bflcap90\revO:\appndxI.doc

AR3 11639GERAGHTYS? MTLLER.INTC.

APPENDIX M

REMEDIAL ACTION PERMITTING REQUIREMENTS

GERAGHTY# MELLER,INC.

Revision No. 01April 8,1998

REMEDIAL ACTION PERMITTING REQUIREMENTS

The Unilateral Administrative Order for the Woodlawn Landfill Site defines the legal

framework under which the Remedial Design/Remedial Action (RD/RA) is'to proceed. The 1993ROD states that the remedy selected is consistent with the provisions of the National Contingency

Plan (NCP), as well as the applicable sections of the Comprehensive Environmental Response,Compensation, and Liability Act (CERCLA).' Given these facts, and in accordance with Section121(e) of CERCLA," "."..no federal, state, or local permits are required for portions of the Workconducted entirely onsite," - - - - - .---,-

Nevertheless, design concepts and.details have considered, as appropriate, compliance with

the intent rather than specific requirements of applicable laws or regulations. The regulations

which have been considered during the design to effectively implement and construct the

components in the RA to achieve compliance are described in Section 2.4 of the Final Design

Report. Jhe Contractor will be responsible for obtaining all the appropriate permits to comply with

federal, state, county, and local regulatory requirements. These permits must be submitted to the

Engineer for revie yland approval no less than two weeks prior to implementation of RA activities

at the site. The required permits include, but are not limited to, the following:

• Building Permit;. _"_. :_ . "..

• Sediment and Erosion Control Permit; -

• Stormwater Management Permit;

• Wetlands Permit;• Grading Permit;• Construction Permit; . . , . , . - -

• Department of Transportation Right-of- Way Permit; and,

• Electrical Permit.

No. work will be initiated at the site until all necessary permits are obtained by the Contractor and

approved by the Engineer in accordance with the requirements defined in the Final Design Report,

Technical Specifications,'and" Unilateral Administrative Order.

G,!Prjea>SBCiplOC\AddOTJdOI\Apo«dm.doc ' " " •----•••.- --—„ - . - - - ---^— - U R 3 I I fi II I

GERAGHTY^ MILLER,INC.

APPENDIX N

RECORD OF DECISION

A R 3 I I6k2GERAGHTY& MTLLER-TNC.

• • ATTACHMENT'1

RECORD OF DECISIONWOODLAWN LANDFILL SITS

DECLARATION

SITS NAME AND LOCATION

Woodlawn Landfill SiteColora, Cecil county, Maryland

STATEMENT OF BASIS AND PURPOSE

This decision, document presents the selected remedial action forthe Woodlawn Landfill site (the Site) located in Colora, Cecilcounty, Maryland, which was chosen in accordance with therequirements of the Comprehensive Environmental Response,Compensation, and Liability Act of 1980 (CERCLA) , as amended,and, to the extent practicable, the National Oil and HazardousSubstances Pollution Contingency Plan (NCP), 40 C.F.R. Part 300.This decision document explains the factual and legal basis forselecting the remedial action for this site. The informationsupporting this decision is contained in the AdministrativeRecord for this Site.

The Maryland Department of the Environment (MDE) has not provideda letter to EPA that indicates whether or not the State concurswith the selected remedy. However, MDE has expressed concernthat: (1) several of the ground water cleanup levels set forthin the Proposed Plan for the Site are more stringent than theMaximum Contaminant Levels established under the Safe DrinkingWater Act, 42 U.S.C. $S 300f jg£ sea.; and (2) the costs forimplementation of the selected remedy may exceed the costestimate presented in the Proposed Plan.

ASSESSMENT OF THE SITE

Pursuant to duly delegated authority, I hereby determine,pursuant to Section 106 of CERCLA, 42 U.S.C. $ 9606, that actualor threatened releases of hazardous substances from this Site, ifnot addressed by implementing the response action selected inthis Record of Decision (ROD), may present an imminent andsubstantial endangennent to public health, welfare, or theenvironment.

DESCRIPTION OF TEE REMEDY

The Woodlawn Landfill Site is a former municipal landfillcomprising approximately 37 acres. The remedial action selectedfor the Site is a final remedy which will address contaminatedground water, contaminated soils, and wastes buried at the Site.The ground water contamination represents a significant threat.Therefore, remediation of contaminated ground water will berequired. The wastes and contaminated soils at the Site pose arelatively low long-term threat. Therefore, the wastes and

A R 3 I 161*3

contaminated soils will be addressed through a combination cfengineering and institutional controls.

Trig selected remedial action includes the following components:

• Excavation and disposal of the soils from the formerdrain field of the Transfer station septic system

» Relocation of the current drain field of the TransferStation septic system

* Capping of the landfill and identifiable cells cf PVCsludge

« Extraction of ground water

• Treatment of extracted ground water onsite and dischargeto the onsite stream

* Monitoring of ground water, the stream, and landfill gas

• Provision for an alternate water supply, if necessary

• Restrictions on the deed and ground water use

* Perimeter fencing

STATUTORY DETERMINATIONS

The selected remedial action is protective of human health andthe environment, complies with Federal and State requirementsthat are legally applicable or relevant and appropriate to theremedial action, and is cost-effective. This remedial actionutilizes permanent solutions and alternative treatment (orresource recovery) technologies to the maximum extentpracticable, and satisfies the statutory preference for remediesthat employ treatment that reduces toxicity, mobility, or volumeas a principal element.

Because this remedial action will result in hazardous substancesremaining at the Site, a review by EPA will be conducted withinfive years after the initiation of the remedial action, and everyfive years thereafter, as required by Section 121(c) of CERCLA,42 U.5.C. S 9G21(c), to ensure that the remedial action continuesto provide adequate protection of human health and theenvironment-

9 - 2-? - ?s Stanley L. Lasicowski DateActing Regional Administrator

•ion III

3R3! \Skk

RECORD OF DECISIONWOODLAWN LANDFILL SITE

DECISION SUMMARY

TABLE OF CONTENTS

1.0 SITE'NAME, LOCATION AND DESCRIPTION ..................... 1

2.0 "SITE HISTORY"AHD ENFORCEMENT ACTIVITIES ........... . . . . . . 2

3 . 0 .-.".HIGHLIGHTS" OF -COMMUNITY- PARTICIPATION ........ .-".". . . .V". . . . 4

4.0" SCOPE AND 'KOXE OF RESPONSE ACTION . . ... .". ................. 4

5.0 .... SUMMARY~OT "SITE CHARACTERISTICS'". . . .". . .T". ......... . V~ . . .". \'55.1". Surface". Features,-"GeijlogyV Soils, "Hydrogeology,

Hydrology . .,,_._. .................................... 55 .2-.--Nature "and ...Extent of..-.Contamination ....."............ 9

5.2 .1 "". GrouTKT Water' and Perched Water ............. 9.5'. 2";:2 .-Domestic- Wells , :...,".". ..". V.v. . .......,.....'... 10.5.2.3 : -Wastes'- and"Subsurface Soils' ................. 11

5.2.3-.1 Landfill. Contents ~and Cell A Area ... 125._2-.3-2/. Cell.B/C, . ......'.". . .". ................. 12

5 .2". 4" " Surface. ".Soils .................. .................. 135.2,5 - Drain Field Soils__.;. .'..'.. _";"".".->--. .-. .............. 135.2.'.-'6 ' Leach'ate Seepsy Seep Sediments, .and the

. Retention Basin ..:.....-......*.."...'..........'. 135.2.7 Creek Surface Water - and SeSiments ........... 14

6.0:: SUMMARY~OF SITE RISKS . . . . . . . .. . .~. .. . . ;v ................ 156.1V -""C6h r nant"s""orf:'C'bncefn '"". 7'."777" . .". . , . 1 ."..'.7'. . . ....... 156.2-—Human^~Health" Ri~sk" Assessment". .".-. . '.- '. . , . . ~ . . ......... 16

6.2 .1-,-.Exposure" 'Assessment . '~". .". .................... 166.2.1..T.'. -Exposure Setting ...................... 16.6.2.1.2 Exposure Pathways' ................... 166.'2 .-1_.3' Exposure "Scenarios,.':'. ....'............. 176".2 .11. 4.--""Qtaantita"tIbn-T6"f- Exposure . .". ......_.... 21

6.2.2 ^ Toxiclty AsseSs-ntent^. ;.". :J.'."?. . . ..... ;'. ....... 22"6.2."3.r:rRisk Characterization-.-. .-. ._. .................. 23

.- .6-..'2.3'.l -Carcinogenrc: '.Risks ../: ................ 236.2.3._2 ; Nonca.1rci"nb_genic'"PvTsks ............... 25

6.3' ""EnV'ir"6n"mentaT 'ftlsk Assessmerit"- . . . 1 ;, ", . .'. . . ......... 26'6.4 Conclusion" ,"_V- ~~-.', . . . ... -.-~-. .-. . ................ 26

7 .0: REMEDIAL-OBJECTIVES AND CLEANUP LEVELS .'.......,.......... 277 .1 "RemedlaT". O"bj"e"ct.ive"s and Cleanup'Lervels . for' Ground

Water _ •- — _:.:;;;., v:.. .:..,:;v:; ;;.TT". :...;......... . 217.2 - Remedial "OB JectTves_ "iind' "Cleanup "Levels .for "Wastes . . 287.3 RemeciiaT". Db^ectives and Cleanup1'L'e'vel's "for Soilis .-.• . 28

8.0 DESCRIPTION OF ALTERNATIVES"". ".T .7~7".:. . w . ..-. ........ . . . . . . ' 28

.AR3

9.0 SUMMARY OF COMPARATIVE ANALYSIS. OF_ALTERNATIVES ........... 419.1 Overall Protection of Human Health and the

Environment "....................................... 429,2 Compliance "with ARARs ................. . .:. . ........ 439,3 Long-Term Effectiveness and Permanence ..•._.. ......... 469,4 Reductio'n of Toxicity, Mobility, or Volume [Through

Treatment ......................................... 479.5 Short-term Effectiveness ........................... 479,6 Implementability ................................... 489.7 Cost ............................................... 499.8 State Acceptance ................................... 499. 9 Community Acceptance ........ . ............:...:. ........ "49

10.0 SELECTED REMEDY: DESCRIPTION AND PERFORMANCE.STANDARDS ............................................. 50

11.0 GROUND WATER REMEDY IMPLEMENTATION ...................... 62

12 . 0 STATUTORY DETERMINATIONS .................... .:. ......... 6312.1 Protection of Human Health and"the Environment .,. 6312.2 Compliance with Applicable, or Relevant and

Appropriate Requirements .. ........................ 6"412.3 Cost-Effectiveness ............................... 6412,4 .Utilization of Permanent Solutions and

Alternative Treatment Technologies to theMaximum Extent Practicable ...................... 65

12.5 Preference for Treatment as. a Principal Element .-. . ^65

13,0 DOCUMENTATION OF SIGNIFICANT CHANGES ......... ... ........ 65

References

Figures

Figure 1; Location of Domestic Wells. -_..... ._ __ .— .V-

Figure 2: Ground Water Elevations, Regional Aquifer

Figure 3: Site Base Map

Figure 4: Plan View: Capping/Pump and""Treat/Stream"Discharge

Tables

Table 1: Constituents Detected in Site "Ground Water .Wells

Table 2: Constituents Detected in Off-site Residential GroundWater Wells

Table 3: Predicted Leachate Concentration of Constituents inSite Ground Water.from Subsurface Soils "" •' "

Table 4: Toxicity Values for Chemicals, of. Potential!Concern

AR3! I6U6

Table -5:.. -EPA. Categ o"rX$£; for., Potentials-Carcinogens

Table. 6: --SufTinii'fy~"Health Risks and Hazards., from Exposure'to.Off--s.ite-""Resi"ciential---Gr-6"i:ind Water.:". ••-.-.'-

Table.,.7: Sumrrtary Risk Estimates (.Current ".Conditions) for. '_. . -Selected,ChiTd-"and "Adult Receptors across Multiple..Exposure. Pathways :'"-." ; .

Table _8/:".,.Summary .i3'ro_uhd Water.:Risk Estimates . (Future Conditions)"for .Selected""Child and Adult Receptors

Table .-9 Ground''Water -Cleanup Levels :fo~rvContaminants withc Car-clriogeri'lc/Health .Effects .._.."_. 7 ".,,... ' . . " . , " . ,

Table 10 :'" Ground' Water.'.Cleanup Levels for-Contaminants withNoncarcinogenicr Adverse Health .Effects

Table -11: Applicable- or Re_levant and Appropriate Requirements(ARARs) and. Guidance-t'to .Be ..Considered- (TBCs) for theWoodlawn Landfill, Site. ".".... " ... ... ... " . -

Responsiveness Summary

A R 3

DECISION SUMMARY

1-0 SITE NRME, LOCATION AND DESCRIPTION

The Woodlawn Landfill site (the Site) is a former "Municipal'.landfall located approximately one-half mile north of the Town ofWoodlawn and one mile north of. the intersection of .Routes 275 and276 in Colora, Cecil County, Maryland. It consists ofapproximately 37 acres and is owned by the Board' of Commissionersof Cecil County (the County).

The Site is situated in an area of gently sloping fields andmeadows and gently to steeply sloping creek valleys. Rural . .'residences and properties surround it in all directions. (SeeFigure 1, The Site occupies parcel-267 oh Figure :T}' . The Siteis bounded on the east and south by. Waibel Road. The northernboundary of the Site -is marked by a jeep trail that formerlyserved as access to the property.. The main access "is now locatedon the northeast corner of the Site, at the intersection ofFiretower and Waibel Roads.

Ground water is the .sole source of drinking water for the 40 to50 private residences immediately surrounding the Site. {Theclosest residence is located approximately 10-0- feet7"'from thesoutheast boundary of the Site). It-"is estimated -that 3,215people utilize ground water drawn -from the aquifer ..which flowsbeneath the Site;

From 1960 until June of 1978, Cecil County operated^a^landfill atthe Site for the disposal of municipal, industrial 'and ' --agricultural wastes. In June "of 1978", the landfill was closed tomunicipal waste and the Woodlawn Transfer Station began operatingin the northeast.corner of the Site. The Transfer:Station, whichis still operating, accepts and compacts municipal and commercialwastes for disposal in another County landfill. Until May of " .1990, liquid wastes from the compacting process were discharged"";.to the Transfer Station septic system.

The primary medium of concern at the.Site -is contaminated'groundwater, which presents both a carcinogenic and noncarcinogenic .---risk to human health. Arsenic, vinyl chloride, and "beryllium arethe chemicals which contribute most to the current ..carcinogenic-,: -risk. Vinyl chloride, benzo ("a) pyrene, .benzo (b.J.fluoranthene,arsenic and 1,2-dichloroethane contribute most to potential - .__future carcinogenic risk. Manganese is the contaminant whichpresents the highest current and potential future noncarcinogenicrisk.

There are also potential risks to ecological receptors at theSite. Levels of cadmium and zinc--in on-site /seep sediments andlevels of mercury in the soils above' the former drain field of _,'the Transfer Station septic system exceed the -criteria that EPAhas determined are protective of ecological receptors". 'Levels of

flR3

aluminum, copper",; lead and silver/, in a stream that crosses thesouthern tip of the Site exceeid..federal ambient water qualitycriteria for :.the" protection ""of. -aqua.txi.c-/li.fe.".:

2.0 SITE HISTORY AND ENFORCEMENT ACTIVITIES

Thei-37-acre Slte^proper/ty was-; a;""'p"£fvvatfe:ry-:-owried.""sand, and gravelquarry before\1960, _when lt:"-was" purchased-by the County. TheCounty operated a ""municipal"" lanidf iir""at.:""t"fie "Site" "from 1960" until."June:"1978, when"_the_^landf ill... was closed to. municipal waste underorder from .th-e:"S"t.ate"'"o"-f-Maryland Department of Health" and Mental .Hygiene ;(M_pHM_H), the predecessor., agency to' the. MarylandDepartment o.f.. the Environment" (MDE) . The landfill.w.as open 24hours..a.day without supervision "unt.il 1571, when the County hiredcontractors.to. .operate the facility.

In June-"of"197.8,~~the Woodlawn Transfer Station, began operationsin the northeast corner qf ."the_..Site. . The Transfer. Station, whichis still bperatlh"g7" ac"ce t"s' anaT";compacts municipal" and commercialwastes which are later., hauled to.the County's Hog,Hill Landfillfor. .disposal .r." ITiquid ^wastes"""derived from the compacted trashwere. _,ori.ginally_ discharged .to . the. Transfer .Station septic system.In May of." 199"Q"," "fbllowlng Van" 'b' eTflow of'effluent from" the'.septic .system- cleanout"Lma"h"h'ole.;;to the ground, surface, liquidsfrom the trash compactors, were rerouted to.an on-site holdingtank. Liquids" in_ the holding tank .are. periodically "taken to' theNortheast" River Advanced Wastewater ..Treatment Plant inCharlestown, Maryland.

From 196.0:.:tb "1978, "" "agrTcuTt"u"r"3T :inujii"cipal and. industrial wasteswere, disposed 'of and sometimes burned "at the .Site. Some of the ,wastes., contained hazardous constituents .or may have releasedha-zardous. -substances upon combustion.

State records pertaining "'to .the. Site document, the. disposal ofpolyvinyl ' chloride'. ;(P,VC) ..slu.cige by the Firesjtpne. Tire;. .& RubberComp'any'TFlrestone-) . The'-PVC''' .! ' , ""which contained residualvinyl, chloride, was initially disposed of ithroughout thelandfill. - -TffMarch" "of' TS B', Firestone 'began' disposing of PVCsludge in... a....designated, disposal area, Cell"" A. "On October 17,1 975 / "MDHMH"" issued an Industrial-. Waste Disposal". Permit toFires.:to"ne authorizing the disposal of PVC sludge in twoadditional areas "on "the'-landf ill property. Cells B and C. Sludge".dispo'sal Cell ?C' overlies Cell "BT<" ; The". 't.wo/ceiis""are referred totogether. as -Cell BK -"'--"-The approximate locations of . Cells A andB/C .are -shown" in Figure" 3 1": ':.";. :-. "/""::^. _ •"T"r'.*,-'J."± -.:.-.- .-

On January 12',"" 1V79'/ th'e Sta 'te-KiE 'Maryran^ci' Water ' ResourcesAdministration., issued .a Complain t; anc! Order", to- ..the Cecil CountyCornmis'S.iohers7" rr:eCting them t.p__appiy fqii.a1 :. Maryland WaterResources -"Designated Hazardous' Substance Disposal Permit for -thelandfill.'""'-" By "March 14, 1979,' the County had complied. EPAsubsequently determined" that PVC. sludge is "not a hazardous wasteand the permit was never issued. ". ..:::."' " . ! ... • ".

SR3I I6U9

On July 16, 1980, MDHMH renewed Fire'StoneT s Industrial "WasteDisposal Permit." The State's renewal of the permit wasconditioned upon Firestone's agreement ta.adhere to., specif ic • .waste disposal practices, to -document and report its wastedisposal activities at the Site, to.implement" a 'ground watermonitoring program at the Site, and to .provide a final clay and.soil cover over PVC sludge disposal.-Cell C. In September 1980,Firestone installed three ground water.monitoring wells tomonitor releases from the PVC sludge .disposal Cell B/C. -Early in1981 Cell C was covered with eight inches of clay .and two and ahalf feet of soil.

In the summer of .1981, the State found contaminants' including • -•vinyl chloride, benzene and toluene in ground water samples -collected from the monitoring wells located downgra"Hient of "CellB/C. On December 10, 1981, MDHMH issued a Complaint and Orderrequiring Firestone to assess .the nature and extent of groundwater contamination beneath the Site. -On the same date, MDHMHissued an identical Complaint and Order to .the County.

In January of 1982, Firestone installed seven additionalmonitoring wells in the vicinity of Cells" A "and B/C"."-" The Countyinstalled five monitoring wells on the landfill property in Marchof 1982. The State installed an additional six wells in 'June "of1982. Analyses of monitoring well water samples revealed thepresence of acetone, benzene, methanol, methylene chloride,toluene, vinyl chloride and other organic compounds in groundwater beneath the landfill property.

EPA proposed the Site for inclusion on the National PrioritiesList (NPLJ on January 22, 1987 and placed it the NPL on"July 22,1987. On June 13., 1988, EPA issued Special Notice ..Letters tofour potentially responsible parties (PRPs), giving them anopportunity to perform a Remedial Investigation/Feasibility Study(RI/FS) for the Woodlawn Landfill "Site-; On December 28, 1986, "'two of the PRPs, the Firestone Tire & Rubber -Company (nowBridgestone/Firestone, Inc.) and Cecil County, entered into "anAdministrative Order on Consent (AOC) with EPA whereby Firestoneand the County agreed to perform an RI/FS with EPA oversight, inaccordance with the Comprehensive. Environmental Response,'Compensation, and Liability Act of 1980," "as amended" (CERCLA) .

The RI and FS Reports were completed on October-26/"1992 andApril 15, 1993, respectively. EPA developed a Proposed ""RemedialAction Plan (Proposed Plan} for 'the Site based on the findings inthe RI/FS Reports.

3.0 HIGHLIGHTS OF COMMUNITY PARTICIPATION

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Pursuant "to ".CERCLA"-§ 113'(k) ('2TTBT "fi).-.(vV; the RP/FS reports andthe.:Propos£d -Plan for :'thez-lWopdlawn Landfill" 'Site -.'were .released tothe public £ 6r; borrirh"§:hf i:;6S"'Mayr" 26, TS_53V "These documents were .:made available—toVthe public: in the Administrative Record locatedat: .the EPA Docket. Room in "Region Ill's Philadelphia office, the'Elkton Public,Library/in El.kton, Maryland,"and the-PerryvillePublic Library in Perjtryville," "MaYyla'ricL _' The notice -ofavailability .of'-'these. ~d6"c.time"n:ts was7 published in the Cecil Whignewspaper, on May 26/~ 1,993.." ' /- '- -:--" '--•—--------'.".-. — •

A public, .comment period .-.on the documents was held, from May 26,1993" "'to'/ITul'y ~2¥,' "a"1 public meeting'was held onJune 8-,"" 1993..";T' At""this meeting," rer>re~s;elitatlves from/EPA and MDE .answered question's "about conditTons" ai_..the/Sit,e and the . remedialalternatives uhder c'ons'l deration. A response" to the comments.received during 'the public comment-.period is included in theResponslvenes~s~"Summary, which is a' part ..a±/ this 'Record- ofDecision "(ROD) . " .

This decisi6n"~~oVo~cument presents the selected remedial action for. =the.Woodlawn Landfill. Site in C.olora, Maryland, chosen inaccordance.with CERCLA,"SARA," and, to the extent practicable, theNational -Oil .and Hazardous Substances .Pollution Contingency Plan(NCP) , 40 C,F.R/ Pa'rt~-3Wr .'The selection _bf'.the remedial actionfor this Site ls""-based ..on the Admin Is tratTv'e" Record..

4.0 SCOPE AND ROLE OF RESPONSE ACTION

The remedy identified .in_.this :.ROD J,s ..the.: s:ole response .actionplanned -fo_r _/t;he Woodlawn Landfill. Site. - .. ' /-, '

Contaminated ground water-presents, the principal risk to humanhealth at-this Site due.'to current ..and potential -future" humanexposure- via ingesti-onjof,-drinking water./ The selectedalternative will uE±l±ze/ '"treatment of ""grouhot""water 'to: (1)prevent "exposure--to-contaminated ground water;' and (2) restore -.the... affected aquifer,.""- ....,.._.'.........— ... ... :._._. _-_.J"-'__........ . ..

Wastes, buried at t.he._Site-are of - concern : to : the extent that theyhave the. potential to .act .as'a continuing source .of ground watercontamination. In "addition', "if has been determined that;contamina"nt.-levels..in-JseveraT""me"dia at' the Site may produceadverse -effects" I'h ek' se'd g'cblb.gical receptors".""" "These mediainclude, soils"-' above" the "former "drain" TielcL of the TransferStation septic", system," ori"-sit.e:'"lea.chate seep sediments-, andsurface.;-:w.ater."o£..:ah" "unnamed creek that_. croSs;e's the southern endof. the Site, w ":./'"•": -;---—.-- -,--— -.•••.....;/-;:~— - - - - - - - - - : : . : _

The .wastes .and" contaminated" soils a"t" "the/ Site" pose a relativelylow long-term:T>;threat""~a"h"d .will he/addressed with a combination of

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engineering and institutional controls.. . These controls .will:(1) prevent migration of contaminants from "the. landfill .and thePVC sludge disposal cells to ground water and surface... water; (2)prevent exposure to the landfill contents, the contents of thePVC sludge disposal cells, and contaminated soils and sediments;and (3) control landfill gas to ensure .protection of human healthand the environment. The surface water and sediments" of theunnamed creek will be monitored in order to. provide a "means for/r"detecting potential future adverse Site-related stream impacts.

5.0 SUMMARY OF SITE CHARACTERISTICS

5.1 Surface Features, Geology, Soils, Hydrogeolocrv, Hydrology

Surface Features and Resources. A portion of=,-th'e Site is coveredby dense trees. Tree cover is densestrrrin the""southern andeastern portions of the landfill property". "Grasses" and shrubscover the north-central portion of the Site where landfilloperations took place.

The land surface -in the north-central area of the Site slopesgently to the southwest from the topographic high point ".near thenortheast corner of the Site. The southwestern portion of theSite slopes steeply down to the unnamed creek.

In the south-central area of the Site, there is a retention basinthat was designed to collect precipitation runoff from thelandfill. & portion of the retention basin contains a palustrin'eemergent scrub/shrub wetland. The floodplain of. the unnamedcreek is occupied by a palustrine broad-leaved deciduous forestedwetland.

An extensive palustrine forested wetland is located along theunnamed creek, approximately one mile downstream of"" Waibel Road.This wetland, which occupies an area of. about 200Q..feet by 500. .feet, was not tested for Site contaminants during the RI.However, it is an area where -sediment deposition is expected to -occur and metals may accumulate. . . . ' . :

There are no federally-listed or proposed endangered=or "." "threatened species known to exist .within a one-mile radius of theSite. Although ,a bald eagle has been recorded approximately twomiles from the Site (in the southeast block of the Conowingo DamU.S. Geological S~urvey quadrangle}," this f ederally-Iis'tec!endangered species is not expected at the Site due to the limitedavailability of its preferred habitat .of lakes, marshes, andrivers. The Site does fall within the known range of the bogturtle (Clemm'ys muhlenbergi) , a U.S. Department pf/the Interior,,trust resource .currently under, consideration for ..fdderal listing"as a threatened species. . __ .. ' - .- .

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The Maryland Historic-Trustr "(the Trust) conducted a Stage 1Acultural .resou'rce.. survey for the Site... .The Trust identified onehistoric .standing structure (McMas t/e /a .Delight) southeast of thelandfill -property" on ""the "";eaS/|:"" lder." . Waibel Road/" (parcel 506 in .Figure 1-) \ /Tt.".c"/o"nclu_ded,/lfha1:,,.'actlyi tles_. at; the Site would have .,no effectTbh" National"-R"e.gist.er;-eligible.r.archaeplogic:al resources.-'.or historic.-standing structures.- "- "-•-"'."" .-"-.- - " .

Geology. The; Site/lies'/In the "Piedmont Plateau region.. .Therocks- of the" Piedmont Plateau are -"metamorphic. and. Igneous. Thegeology .of . the Site.:area-has been described, as sand and graveldeposits..-overlying saprolite .and'the parent .metamorphic bedrock.The_. sand and gravel deposits-.are- of" the "Upland Gravel unit and

are,ir>robably .fluvial .deposits o"f .t.he"".an"cestral"Sus.quehanna River "system.. ,....— .._.__._..-.=,...,--.. -- •- -•- — ---_-- ---------- -, . ...

Tw.o..__bedro.ck_.forma~tions underlie" the Site: a gnelssic-.granite" and.a-metadlorlte,.: ". .The gnei"ss.ic-g;ranlt:e'..undejrlies. the saprolite atthe soil/rock interfa~ce"/In-all areas of "the"Site..except thenorthwestern section. The. uppermost; .rock unit in this section is-me.tadiorite",,.: -The:..metadiorlte dips beneath the gneissic granite.-.in a zone that- "appears to coincide with a lineament in thenorthwestern. portion of ~ the Site, that was identified on an aerialphotograph. The gneissic_granlt.e...±s"; a; plflk, coarsely__ crystallinerock with weak foliation-.- The "metadiorite. Is a black and white,finely cr"ys~ta~iline' rock with pronounced "schistoslty. Both thegneissic granite,and. the metadioxite contain interlockingcrystals-of. feldspar, quartz, hornblende,-mica and other"minerals-.-" .These minerals contain silica, iron, aluminum,manganese, "calcium," sodium, potassium and trace-: elements . Uponweathering, "the gneissic .granite and .the metajdiorite break downinto-day minerals-/ siTica /and!" oxl.de s'"":" of. 'iron and manganese. Theiron and manganese 'O-xide-s . become; "more/soluble ..in oxygen-poor orreducing environments., and -can be transporte/d by the groundwater.. .This natural "s"ource" may acc'o'unt for 'some' of the'.'iron .and.mangane.s'e, in. the -grouncLwater ,a.t ..the Site.. ..." . .

A thick layer of/'re'sTdual "soil /rsapro'liteT'oveflies the bedrock.jThe residual soil "".is/very" gFanula""r. "V-There,ls_ no evidence of alayer, that might ]cestr_ict,..gr"QUlid" water"." "flQw./between the. soil andbedrock. Fractures" in" "the bedrock/that intersect the surface. ;provide, conduits .f.or/.gr"6urid;;water""Tlow a'cfbss the" contact betweenthe soil .and the. bedrock.

Soils . All unc'dh'soildated materials. .iyin"g_aboye the bedrock are •classified here, as - s-o±ls. The stratigraphy of. the soils frombo.ttom to" top "can, be-,generalized :a.s fpllq.ws: residual soilsderived from" we-athering"/6"f" the" 'bedrock'." Is.aprolitej ; transportedsoils "including stream-derived sands: and 'gravels (.alluvium) and

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soils washed from hills (colluvium) ; material such "as" waste andreworked natural soils (fill).

Saprolite overlies the bedrock throughout the Site. Thethickness of the saprolite .varies from 90 feet"in "the" northernpart of the Site to 15 feet in the southwestern part^ of' .the_ Site.Deposits of alluvium and colluvium lie above" 'the saprolite in

many areas.of -the Site. These deposits were the source materialsfor a sand and gravel operation at the Site that predated thelandfill. The alluvium and colluvium "contain layer's" of siltyclay and clay in some areas of the Site. . the thickness of thealluvium and colluvium varies from 10 feet" iri "-the northern partof the Site to 50 feet in the western part of the Site.

The fill material at the Site consists,of waste materials that " 'were deposited into excavations that.were created during the timewhen the sand and gravel operation was in existence, rearrangedalluvium and colluvium, and mounds of reworked sand and gravel..

Hydrogeology. The hydraulically-connected"saprolite'and bedrockcomprise a single aquifer in the area of the Site. In the centerof the western boundary of the landfill property, there -is anirregular bedrock surface as interpreted from differences indepths to bedrock from nearby borings. This irregularity appearsto be in or near the area of the contact between the gneissicgranite and the metadiorite. South of this area, the soil Isunsaturated, except for perched water zones. "-These factorssuggest that this contact zone may be a pathway for.ground waterflow beneath the bedrock surface. - :

The ground water potentiometric surface for" most "of" the Site is -in the saprolite. Near the southwestern corner of .the Site (nearmonitoring well ITB-4), the soil Is unsaturated and "thepotentiometric,surface drops below the bedrock/soil interface.

The local ground water flow directions are shown in Figure 2.There is a ground water divide, or high point, in the. northeastarea of the Site. Ground water from this divide" flowsdowngradient to either the south-southwest, west, or north-northeast. The regional ground water flow is toward theSusquehanna River and Chesapeake Bay (west-southwest). Localground water flow directions are -in part influenced by localtopography (land surface and the buried bedrock surface), i*e.,the flow directions are usually down slope. L/o"cal ~f lowdirections are also influenced In the bedrock by fractureorientations.

There is a discontinuous aquit.ard ab.ove_ the unconfirmed aquifer .j-"Clay lenses within the alluvium/colluvlum in" the urisaturate-d zoneintercept infiltration water and create.perched water zones -in

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isolated areas, of the a-lluvium/colluvlum"and" fill "material. . The.clay lehses /lnhTbit vertical water flow "through . the. soil, and filland redirect ...the .water, .".laterally to "seeps./south of Cell B/C andin the western-ce"ntral portion of " the.Slte. '> a • «; *;Site Drainage. Site surface;. dralna' e i4vla" "6Verla"nTd flow isprimarily" sbuthwestward .tow_ard the unnamed creek. Some of. thesurface^flow oh "the-l/eastern side of..the landfill property (near. "Cell. B/C}" is' "channeled, south, then west, into 'the. retentionbasin."" When precipitation is...heavy, or of long duration,accumulated runoff""'-TlrT the "re-tention_ basin spills. o.ver into a- man-made-swale 'that ..extends.".s~6uth"west"w~a~r.d into the unnamed creek.

The-., unnamed, creek, which flows to the, west-northwest, entersBasin Run Creek, "a" "State-designated trout stream, approximatelyone-'an'd-mr-half-.mile"s"/downstream from/the Sitj&. . JSasin .Rundischarges-: into Qc£;oraro.: Creek' approxima"terly three-and-a-halfmiles .northwest" o£.""the S/ite_; ...Qctorarq Creek flows westward untilit..joins the .Susquehanna River,' which is. the major source offresh water,., for/the Chesapeake "Bay. " ' ' ' •

Surface Water - Ground Water Interactions. The relationshipbetween gurface' ate'r" and" ground "'water is characterized by thefollowing types"7"'oT'recharge: /.'IT)' ""recharge, to."ground water.. fromthe- surf ace, .o"f"v;the...Site; (2) recharge by" precipitation to .perchedwater, zones' that" supply seeps; and' (3). recharge, .to surface waterstreams 'by ground water.. ._ . .—^ . . .._....-,--;,,..-_,.„_--,„,.. _ . . . . . _ . . . .

The fir.st;;±ype of_ e<;:har er"in"v.6Tves...th .e ...flow of water from thesurface, of the' S/Lte:;t6/:-t.he ground water. The topographic higharea"-that"'extends along the; northern, boundary of the landfillproperty serves "as •a:":maj"or":rech"arge. ."a" rea." -. This recharge area is.the primary area .In." the vicinity ."of "the : S_ite/".whi.ch allowsprecipitation falling on";.the ground to percolate through the soil-and into'the regional aquifer." . . . . "—_ .....

The second type -,of .recharge. involves seeps which are fed byground water;.in the perched water . one. located in the 'Cell .B/Carea. : "'Seeps.: w"ere%_identlf led along a bank in the area of - ...monito±±n"g well''TlTB-5V''./T.he'/se.eps";occur::where a confining claylayer intersects./the ground"surfacev'causlng water flowingdownsl.ope- in~~the^perched 2pne_to,.surfac:e^___-The perched water zone

. is recharged. directly b Jpr cirj'itatTon hTcn "percolates throughthe surf ace ~s£xils. an d"burTe"d"" wastes ."""" An addltlbnai . seep wasidentif-ied-ln""the northwest portion "of the landfill, . This seepcoincides-with a ..subsurface lineament 'and" flows -from the landfillto- .the. west, :.I.~IT~V::-: ";-. "" •" ;--—-- --- - - • v - - • - - - - - -- _ . -

The third type of -recharge involves gr'ound_w.ate.r recharge tosurface;;wat"er, ."JGro"unti" water :"fl"ows" to "the :'soutnwest and to the

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north away from the ground water .divide located in the northeastarea of the Site. Ground water flowing to .the southwest from thedivide .eventually "reaches and provides^some. recharge .to theunnamed creek. Ground water, flowing north from the divide - . , .eventually reaches and provides some recharge"to Basin Run_Creek.

5.2 Nature and E_xtent of Contamination

In accordance with the Consent Order signed in 1988, Firestoneand the County performed a RI/FS-to assess the nature and extentof contamination at the Site. They also"performed a RiskAssessment In order to evaluate the human health risks and-theenvironmental Impacts associated with exposure to Sitecontaminants.

Three sources of. contamination were", identified at. the Site: PVCsludge disposal "Cell B/C, wastes disposed of- in the 'generallandfill, and effluent from the Transfer Station septic system.PVC sludge was not encountered in the area thought to be occupied.by disposal Cell A. Therefore, it was not possible to verify thelocation of Cell A or to collect samples of "the Cell A sludge" foranalysis.

During the RI, ground water -underneath the landfill property andadjoining properties was sampled and analyzed in order todetermine the horizontal and vertical extent of ground water .contamination in the aquifer underlying the Site. -"Ground watersamples were also collected from residential :wells "-surrounding " -the Site. PVC sludge in Cell B/C, soils, leachate seeps and seepsediments, surface water and stream sediments were also.-sampledand evaluated. The sample results are "summarized below.

3-2.1 Ground Water and Perched Water

Thirteen additional monitoring wells were installed at the Siteduring the RI. Figure 3 identifies the ground water monitoringpoints. Transfer Station water supply well TSTA-1 and monitoringwells ITB-1 through ITB-6 tap the bedrock portion p_f. the aquifer.Well TSTA-1 was drilled to a depth of 228 feet.. The. bedrock

monitoring wells range in depth from 45 to 163 feet/.~ Wells ITP-1through ITP-3 are perched water monitoring wells that range in ._depth from 11 to" 20 feet. The remainder of the monitoring wells,i.e., the F-, B-, OW-, and SW-series wells, wells ITS-l .throughITS-3, and well TSW-1, are screened in the soil above thebedrock. The depths of the soil wells. range 'from 13 to'92 .feet.'

Ground water samples were collected from 30'monitoring wells andthe Transfer Station water supply well (TSTA-1} . the'se" sampleswere analyzed for all Target Compound List '(TCL) parameters plus

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acroleln,' acrylohitrile. .and 2-chlorbetnyl .vinyl ether, and for ."all. Target.-Anal yt'eV-List. /(_fA )/"par.ain"e"t"e.rs, except selenium andantimony. ----- /!"".//. " " 7T."! "" .

More than 40 diffe're_ii£""a "a ;£ In ground water .. .samples cbllected/Trom :the monitoring wells located on andadjacent "to._.the..JLandfill .property/ including several at ...concentrations that exceed^Maximum Contaminant-Levels- (MCLs) for.public "drinking water....STUpplies . The contaminants, that are.of . -greatest .concern from a, human, .health .perspective are vinyl.chloride, "1,2-dlchlor6ethane..-'a"nd other .volatile 'organic compounds(VOCs), "polyhucTear /aromatic hydrocarbons^ (PAHs) , bis(2--=-ethyl.hexyl)phthalate, - pentachlprophenQl, several pesticides,arsenic, "catlmium 'and man§ahese::.'".'' •'!--""" - ':.:"-""-.'"' '"-'

The vinyl chloride: contamination "is primarily/limited, to . the F-series wells/that ./tap 'the soil., aquifer J.n_ tHe_ area of... PVC sludgedisposal Cells-A .and B/C'.'" The ...highest concentration of vinylchloride -detected, in the "grpund_w.ater was _520 microgr.ams "perliter (Mg/D- ..in "well F-6. ' /Vinyl' chloride'7was/"also -detected in a .perched" water: mo.nltorIiref'.well downgradient; of./pell B/C. (7 (J.g/L inwell ITP-2) "av bedrock _well ..along the "northern bprder" of thetlandfill ITS' ' g.ft in""weTl' B-Tr/'" V'fe^drock"well located 'approximately 7.0.0 '/feet/.-Seyond the nprthe;rn_ boundary of thelandfill pr6p"er"fy" (b"".Tr' bedrock wells alongthe western border_ .of.,the-.landfill--(up to."0..6 . gVL in well JTB-3), and bedrock wells..lii the "south-central area of the landfill.""(up to.-L4 Mg/L..in well ..JTB-4) ... Elevated levels... of... 1, "2-dichloroethane .were detected...ln "a soil-monitoring well near thenortheastern..corner' of, the .landfill-property" (410 -M-g/L In well "TSW-1) and a perched water monitoring Well ' .(15. fig/L in ITP-2).Trichloroethene--and tetrachloroethene" were./found in monitoringwell -TSW-1 at" coficifit'rations" of" 60 "Jig/L/and ""8" M-g/L, respectively.Maximum total.-PAH concentrations ranged, from' 6 M-g/L in perchedwater monj toring"; well iT.P-3. -,to -44 'M-g/L^in': soil' aquifer _mpni.t..oringwell TSW-TT'and 13..ug/~L in" bedrock, monitoring well ITB-2. Bis(2-ethyl.hexyl)phthala.te, w"as. ..ple_t-ecte:d. in ground, .water samples .collected, from bedrock and soil aquifer and perched water 'monitoring well_sjthroughout .-the"-..Site at concentrations up to -140M_g/L. .;.(w"ell. .OW--21 ..//"Ten'tachlorophenol was detected in one:.soilwell". (T' g7L™I"n/Se:ll B .4)" : and" in one bedrock, well (4 (ig/L in wellITB-4) . Various 'pesticides were/.f6 u"n"d"_lri/s"alTiples" collected fromseven soil monitoring wells, a perched water monitoring well anda bedrock monitoring well.// The_ highest pesticide concentrationwas .0.24 'Hg/L of :-'Endosulf.an I, which was. found in well OW-i.

Arsenic "and cadmium' were "detected"., in "ground water and. perchedwater samples.-"at./c.oh.centratlQns up to". 8 ~]ig/L' (well SW-1) and 119

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M-g/L (well F-6} ,; respectively. Elevated..levels of.- icm .and .manganese were found in the aquifer.underlying the Site and. inthe perched water zones on-site.. Maximum manganese" .concentrations ranged from 12,600 M-g/L in ground water extractedfrom the bedrock (well ITB-4) to 24,200 | g/L in ground waterextracted from the soil .(well F-7) to I, "940 M-g/L in the perchedwater zones (well ITP-1). Maximum iron concentrations rangedfrom 10,200 g/L (bedrock well ITB-4) to 43,500 Hg/IT(soil well"F-7) to 59,500 M-g/L (perched water monitoring well ITP-1) .

5.2.2 Domestic Wells

Thirteen domestic wells were "sampled by Firestone and the Countyin both March and November of 1990, and analyzed. for" the .TC.Lparameters plus acrolein, acrylonitrile and 2-chloroethyl vinylether, and for the TAL parameters, except antimony and selenium.EPA analyzed VOCs in samples collected from seven" ;~additional . .domestic wells in August of 1991. . . -"_.„.. ... ' / . . ; .. ~. " ._ :

Most of the domestic wells in.the area of the Site (Figure .1) arecased to a depth of five feet below the bedrock surface. Belowthis depth, the well bores are open to "the bottom of the hole.Well completion reports indicate that ..two domestic wells may varyin design from the others near the Site. The well casing atparcel 309 may have been installed to. a depth above the bedrocksurface. The well at parcel 506 may not extend into, the bedrock.

Site-related contaminants were found in two residential,wells.The domestic well at parcel 309.. is. contaminated with detectable. ,levels of vinyl chloride. The highest concentration" of - vinyl ..chloride detected in the well was 0.6 M-9/L, which is below theMCL for that chemical. A carbon adsorption unit was installed atthis residence In December of 1990 in order to remove vinylchloride. No contamination has been detected in the.treated wellwater. Water collected from the domestic well at "p'arcel 506. .wasfound to contain elevated levels of manganese. The. highestconcentration of manganese detected in this well was- 3,060 M-g/L.On September 9, 1993, EPA approved of a work plan submitted byFirestone and the County for the design and installation of atreatment system to reduce the level, of.-jnanganese In, the domestic"well at parcel 506 to an acceptable health-based, level....

Other residential wells may be. contaminated. Arsenic was foundin ground water samples collected from the domestic wells locatedon parcels 530 and 516. However, the level of .arsenic detectedin these samples (2 Mg/L) appears to be within the ..range ofbackground arsenic concentrations found in Cecil Co*i_nty~ groundwater. Beryllium was found at a concentration of-2.2 M-g/L' in"one of three samples from domestic wells on each of .parcels. 515- .

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and 516. ""The1 beryllium detected _in "these samples may be theresult-.of ..laboratory contamination;" beryllium was not, .detected inground.water beneath, the landfill "property. /

5.2.3 Wastes and Subsurface Soils

During - the RI",". F.lres"t""6ne "r and :."the ""County" completed "3D .borings inthe waste material at .the Site :..in"-""orde"r "t"g.-"def ine the vertical . -and lateral extent'of .the wastes and tQ.::e.valuate . treatment andcontrol ...option's1. Five/ boring's/ were completed In the. generallandfill areaV 'TwenTy" boring?; were- /completed in the Cell B/Carea and -five-in the area- 'thought^ to. be., .ocp.upied by Cell A. Thesamples were .analyzed -£6r".tiie..:XCL ."parameters 'plus acrolein,a'crylonitrlle."-and 2-chloroe.thyl vinyl ether,' and for the TAL_ .. .parameters, extfept antlrnbriy and selenium.". EPA .completed eightadditional-borings in""October' 19/S"2 Ih"''order/to "further evaluatethe', volatile \6r7g-"ahi1c"--""con'sti.t.ueriit"s "of th'e waste material in PVC" .sludge disposal-..Cell'B/.C./. "" /"./'///""/'.\ ... / '..."../. . . V I "

5.2.3.1 Landfill Contents and Cell A Area

Nineteen samples we're "caiTecte'd' from/ten .:HorIhgs-in-wastecompleted in the_general_ landfill and suspected Cell-A'areas..Low c6n"c;:entria "ons:""":of...organic Compounds .a.n jtte.ta.ls.-were found inthe . fill material-JIn' the general .landiEiir a.fea," in the native.saprolite surrounding the "fill, "and In the ."suspected area of..CellA. 'The organic-'chemicals" included VOCs .(which were^ different.".from ^the VOCs found" at levels' .o_f/ concern" in" "the .grpund water) andsemivolatile-,,6rgani.c/ compdunds", ""i.nci"_iadiin_g__.)5i:s"(2-ethyiheisyl) -phthalate. Gene"ra:"ily" low":JUevei-s'"'of" InorgaTii'C- elements weredetected- in "the . subsurface:-soi.l- and waste samples. .

It should be/ hoteoTjthat the analytical__resjults fo_r. the 19^landfill waste and. subsurface, soil samples .are not considered tobe. representative .of all of .the/wastes^.and contaminated .soils inthe lano/f ill... _. -A lstatlsti.cal sampling; plan .would" need-to be. . -implemented "in orderr_to obtain a representative .measure- of . thechemical constituents o.f "the landfill wast'es . 'However, detailedcharacterization ofr"a: lahdf ill's contents.: is. costly and. the -volume and" heterogeneity" "of" lanciflll .contents: often makes" .treatment impracticable-/^Conducting Remedial Invejstigations/ --Feasibility Studies'7fpr-'-:CERCLA 'Mu cip_a'l~~fa f.ill Sites,EPA/540"/P-9"17.t)""OT, February "T991-^ ;fherea£tef7;..."EpA Municipal . 'Landfill Guidance"]")'. Therefore, such detailed"^characterization .is-generally "h"o ";"n'e"_(re-s.Sa;.ry""s;i_h5"%; i:h accordance withthe -NCP,". is of t'erf the 'most' prac"£i"cable" technology and does 'notrequire".:s:.ilch infurrSatlbn; —-— -— --

5.2.3.2 Cell B/C

Twenty-seven samples/". oJ.r.EVC/.-sludge" were-collected from 20

12

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different boreholes drilled, into the oneracre. Cell B/"C waste-area, consistent with the EPA Municipal Landfill Guidanceregarding potential hot spots at municipal landfill—aites. '.-Generally low concentrations of organic "compounds arid metals-werefound in the PVC sludge samples. Among the VOCs found in thesamples were 1,2-dichloroethane, trichloroethene and vinylchloride. The highest concentration of vinyl.chloride detectedin the Cell B/C sludge material was 7, .^milligrams per kilogram-(mg/kg). The mean concentration of vinyl chloride in.the CellB/C PVC sludge was estimated to be 290 mic'rdgrams .per-kilogram(Ug/kg) , based on the analytical data collected for/.the .RI and . ,treatability studies and the additional sludge sample analysesconducted by EPA. Semivolatile organic compounds detected in theCell B/C sludge samples included bis (2-ethylhexyl.) phthalate (atlevels up to 1,200,000 M-gAg) and other phthalates._.. .Generallylow levels of Inorganic elements were detected in the Cell B/Cwaste material. ..

5.2.4 Surface Soils

Eleven surface soil samples were collected from the" generallandfill area and the PVC sludge disposal cell.areas. These.samples were analyzed for the TCL parameters plusacrbleln,acrylonitrlle and 2-chloroethyl vinyl ether, and for the TALparameters, except antimony and selenium. Low levels of organiccompounds were detected, generally at concentrations close to themethod quantitation level.. These compounds included.VOCs andsemivo'latile organic compounds, including PAHs. inorganicelements, including arsenic and beryllium were- also'/~dete"cted inthe surface soils, at background levels... .. .. .:_..__ ..

5.2.5 Drain Flald Soils

Thirteen subsurface soil samples .were collected from ."areas aboveand below the former septic system drain field, and three, .surfacesoil samples were collected from areas downslope of the."manhole. _at the head of the former drain field. (Two -O-f. the., surface soil,samples were collected and analyzed by EPA.) The purpose.was toevaluate the impact of releases.from the septic"system on Sitesoils and the potential for contaminants In drain "field .soils t.oleach into ground water. The. drain field soil samples "were.analyzed for the TCL and TAL parameters. . ._

Low concentrations of organic compounds were .detected in drainfield soils, generally at levels close To.-, the method. quantitationlimits. These compounds included VO-Cs, semi volatile organiccompounds, including PAHs, and several pesticides. .. Severalinorganic elements, including arsenic (at levels.,up to 22.1mg/kg), mercury (at levels.up to 3.9 mg/kg), and beryllium were.found In the drain field soils. The levels, of beryllium in the.

13

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drain field s'o'iXsVare 'within" "the" range or" '.background levels inCecil County. ' " ": "" V" ./ " """" ' /V*V"" "" "''

5. 2. .6 Leachate Seeps , Seep Sediments and the Retention Basin

A sediment sample- was 'collect.ecr from.-.each-o.f. .three leachate seepsIdentlfierL-during the :R.r" and from the • retention basin in thesouth-central area ofVthe. landfill. "A leachate sample was. .also.collect"edV"fr6:rfrTe""a'ch_o.f""the three, seeps. : A "surface -water .sample ...was coll.ec ".d/ir5m~'the' retention basin. These, samples were.:analyzed for t:he !C£ acrDie"in7.._acrylonitrile and2~chloroe;thyi" vinyl ethe.r,' antT.for : the TAL parameters, exceptantimony and" selenium'. * . . . _ ' . . .

Leachate- -seep "samples -contained levels of the VOCs benzene,carbon disulf ide, : "Chlorobenzene, ethylbenzene, toluene and totalxylenes, with maximum concentrations" "ranging from 2 Mg/L-to 82M-g/L, and levels, of "the" semiv-olatiie organic chemicals benzole- . :acid, 1, 4-dichlorobenzene, diethylphthalate, naphthalene andphenol, with maximum concentrations ranging /from "'3" M-g/L to. 3.8M-g/L. Le.vels""/6"f /'aluminum (up to 138 ug/L) , copper (2 . 1 Mg/L) ,iron (up to 69,'4"0*0 ~fig7'L} ," "lead - (up to. 10. 7. M-g/D , 'manganese (upto 1,090 >g/L") , "nickel .(up to. 22.4 M-g/L)-, zinc -(up to 23 . 0 Hg/L')and other ..metals we're :als"o found "In/the leachate seep samples and'the. surf ace .water- sample... collected from the retention basin.

Sediment ""samples c6He_cfceji frpirt" se'e' a~rea:s~ h"d the retentionbasin containe'd VOCs, -includirig ace'tphe, bhiorof orm, 2-butanone,toluene '.arid total . xylenes, with maximum . concentrations rangingfrom 2T Jlg"/kg /tp. .H/ g/kg, and". semivolatile. organic compounds,including bis .(2-ethylhexyl j.phtnalate . at levels up to 5,800 M-g/kgand a wide range l'~of" PAHs, with maximum .concentrations rangingfrom "160..M-g/feg to" "7.8Q ."pg/kgV Elevateci- levels of" c'admium (up to10.57mg/kg) and..:.zlnc (up. to". S^S/mgTlcgl were' ietec.ted .in seepsediments. Arsehlc- 'a'TTQ/ber.ylilum we're . a/lso /Detected in seepsediments at background levels... ... .,:.....

5.2.7 Creek Surface Water and Sediments

Ouririg." "the Ri;, "six secilment samples and six: surf ace water samples•were '"collected., from upstream 'an downstream/areas of. the unnamedcreek that flows acr"oss::-'the southern"""tip of ""the Site. Thesamples were;:.:3rra"lyzed, fo-r t he T-C_L_pa_rarneters i/ plus acrolein,acrylonitrIle,/-a"n"d:-2-,cnl.oroe,t]i"yI 'VTnyl ether,' arid for the TALparameters, ."e"xce'fft: aTOlM *Low" levels of'.' the - semlv'dlatlie organic compounds di-n-butyl- .-phthalate, N-nitrQspdlphenylamine and pyrerie were found indownstre.ara' S-urface"':"w"al:~er- samples-. . """Dl-n-butylphthalate was also

14

flR3l166

found in an upstream surface, water sample at a level similar to .the downstream level. . _

Twelve metals were found in downstream surface" water ...samples andeleven were detected in upstream surface water samples. Themaximum concentration of manganese" found In downstream surface".":water samples (191 Mg/L) exceeded the highest level, of manganesedetected in upstream surface water samples (21.4 Hg/L). Maximumdownstream concentrations of some metals were slightly elevatedcompared to maximum upstream concentrations of- those metals:.aluminum (143 M-S/L and 105.9 M-g/L/ respectively); copper(6.6 M-g/L and 4.2 M-g/L, respectively); iron (180 ."M-g./L and118.8 ug/L, respectively); nickel -(7 . 9 . M-g/L and 6 M-g/L,respectively); and zinc (13.3'M-g/L and 9.5" M-g/L, ".respectively) .Lead was found in a downstream sample at -a maximum concentrationof 3.7 Jig/L but was not detected in upstream surface"watersamples. Five other metals occurred at comparable levels inupstream and downstream samples. ... . . . . . . . . . .

Low levels of the VOCs 'chloroform and tetrachloroethene werefound in upstream creek sediments. Chloroform was "found In onei...downstream sediment sample at a concentration of 2 "Mg/kg.Semivolatile organic compounds, including benzole acid at a"" levelof 430 Jig/kg, bis (2-ethylhexyl) phthalate at a level" of 140 u.g/kg,and several PAHs at levels ranging f"rbin l20. Jig/kg to 160 J^g/kg,were found in downstream sediment samples. Bis.(2-'ethylhexyl) -phthalate was also found in an upstream sediment sample-at alevel of 140 M-g/kg. Downstream levels of several metals in 'creeksediments, including chromium, cobalt, copper, iron, manganeseand nickel, were somewhat elevated compared to upstream levels.

6.0 SUMMARY OF SITE RISKS

A baseline RIsk_Assessment was prepared. in order to identify anddefine p"ossible""ex~lsting, and future health risks and potentialenvironmental Impacts associated with exposure .to the chemicalspresent in the various environmental media at^-the "Site if noaction were taken. The baseline Risk Assessment provides thebasis for taking action and indicates the exposure .pathways thatneed to be addressed by the remedial action. The baseline RiskAssessment can be found In the Remedial Investigation Report(Revision 01, October 1992) prepared by International TechnologyCorporation (IT).

6.1 Contaminants of Concern

Since the principal risk to human health presented by conditionsat the Site is risk from exposure "to contaminated "ground water,' "the primary contaminants of-.concern are those chemicals, detected

15

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in the ./ground "water """at :th-e--S.i"t.e .and^thpse". chemicals in the wastesburied._.at -the Site:.-which, "have.-the pbtential.-_t;.o .contaminate .groundwater as-'-a.-result._.of../leaching." ' These" chemicals are presented inTables 1 through ...3.."1 ...._;•...:_'. .::":;":.: "•'."-"".."

In addition, mer.c"u"r' y" :s//d'et'e_c'ted'In soils, 'above the former "drainfield of."the Transfer" tati;"pn_;s"eptlc\s"ys'tem; cadmium and zincwere found in on site se/ep- sediments; • and aluminum, copper, leadand silver, were "detected/ in_ s;urfa.ce /water/"samples. collected .fromdownstream, areas- or"" e"J~u"rma"me_d" creekV . ...Tn.ese .metals are ,contamina'nt's Jo-f.""concern" "for"/ ecological 'receptors. •/

6.2 Human Health Risk Assessment

6.2.1 Exposure Assessment

The,..objective .of'' "the exposure-.assessrnent/ls 'to estimate the .amount of "..each" chemical... of. potential.', concern " at-a site . that is .. .actually taken into/- the., body (i.e.,' the intake level, or dose).The.primary component's* of.-the ..exposure' assessment Include a "characterization of .the_.jixposure "setting, a/p'athway, analysis,identificatio"n"Of/;p" s Lble./e.xposure conditions.,, and an1 estimationof exposure'. '-/The results of. the e"xpos^r^>^'Assessment are : combinedwith chemical.r-speclfic;/'t.cDxi-city 'lnfo'r.ftLa'tiori.lIt.o, characterize 'potential" risks. - - - ' - - . • .........

6.2.1.1 Exposure Setting

Although some.jare S ."of/the. Site.'are" :f"enced, most of. the-Siteboundary/ "is" u"h:Fe'"hc"e.dl/ /Tjierre.fo. Is possible at theSite.1; . Potentially _exjjo'sed/p6pulatiohs-/.lhclude_residentialpopulations"located" near'-the Site, and child qr'adolescenttrespassers. -- - ~: -~" ---,----—-":-"----"—"-- _-——^- -± - -— -

6.2.1.2. Exposure Pathways

As. noted; in 'Se.ctipn/ 5...2 3,;.,i, characterization of thelandfill wastes" "during"" the RI would..have;, been costly and wasdetermined to be":unhe"ce/:s:a';r"y'since coiTtainmen't' Is "the most.practicable.^te.chnolQgy for managing a/large'yo.lume of . 'heter xgeHe Us/' aSte ' i'n/ muiiic p'al. landfill/' The PVC sludge indisposal. Cell.:~B/C. was /adequately .chafacterlzid" and its leachingpotential- evaluated;.during _ the 1. .T.ke.. results .are: summarized inTable-,3..:of-.£Hri""ROD.. Since; tne./wastes, in the, landfill" were notfully characterized," it/was....not. possible to. reliably determine theleaching pot n"t.iai:,;o£...t .QSB/-"wastes:. Ho_wever.A; Tables 1 .and 2.include contaminants of/concern "found'Tn .ground water at the Sitewhich have not.:been..detected, in .the Cell. B"/C- wastes. " It is '. 'reas-on'able .to./conclude that those/contaminants were derived "fromthe wastes In the.landfill .and from the natural"soils.

16

AR3I!663

A complete exposure pathway consists of ...the, following, elements; .(1) a chemical source or a mechanism for contaminants to_be., ~;released into the environment; (2) a .medium through whichcontaminants may be transported, such as-water, soil or. air; (3)a point of actual or potential contact with contamiaa.nts _(exposure point); and (4) a route or mechanism of exposure, suchas ingestion, Inhalation, or dermal contact.at the exposurepoint. Both current exposure .pathways and potential future... . ..exposure pathways were evaluated in the Risk Assessment.

As noted in Section 5.2, above, three sources, of contaminationwere identified at the Site. The .release of c6ntarrun"ants intothe environment was documented during the RI.

The following contaminated media and potential routes: - of exposurewere evaluated In the Risk Assessment:

Ground water pathway*Ingestion of contaminated.ground water, includingpotential leachate from subsurface soils and PVCsludge

- Inhalation, during showering, ofvolatilized groundwater contaminants, Including contaminants in •potential leachate from subsurface, soils.-.aiid -PVC . ....sludge -

Dermal contact, during showering, with, contaminated .ground water, including potential leachate fromsubsurface soils and PVC sludge .

Soil pathway

- -Incidental ingestion of contaminated surface soils

Inhalation of wind-borne surface soil particulates

Incidental dermal contact with" contaminated surfacesoils . . _. ...

Sediment pathway

- Incidental ingestion of sediments, "~lneluding seep,retention basin and creek sediments

Incidental dermal contact "with sediments, including .seep-, retention basin and creek sediments

Surface water pathway

17

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--- Dermal"contact" with constituents.in surface water,including "leachate .and-surfa"ce.,water'in the creek and-retention 'basin. '

6.2.1.3 Exposure Scenarios

The -expos re--a'-£-sTe :sTfiel potential futureuse :c : contaminated"ground water .and... current recreational use ofthe Site." The averagirig;" time/ us'ed; J_n .a l ..'exposure pathway"calculations';'f"or..ca;rclh-oge.ris is: ."based on "an" adult lifetime of 70years. The, .averaging./tii e'/ui ^ "" ! exposure pathwaycalculations" "for chemicals :wi"th noncarcihb"gfenic-health effects isequal to.-..th_e_rduration o..f exposure.'' The other assumptions used, toestima-t.e-™expos=iar:e':pioin1:" cbncentra.tiohs ahoT ;to /quantify exposureare" summarlzea. below for/.each pathway evaluated in the RiskAssessment"."" -^----r-" •----——--- - - - - - .- ;:;.

Ground Water Pathway. The risk associated with exposure of arearesidents, to ...contaminants present "in presidential well water . wasquantified in" the Risk_Assessment,. Potential, future exposure, tocontaminants" pre_se"fit "in"." ".ground/ water' 'beneath "the landfill...property was ;avlso -considered in the Risk Assessment based.on anassumption that .a public.water supply well, would- be...placed in thecenter of.. the.-'.exis.ting 'cont'amlnant "plume. " A second future usescenarlD"~consTcler'Tea exposure to ..ground water contaminated withthe: highest levels of .vinyl chloride .that, were predicted to. occurin'the aquifer, 'beneath., the. landfill property 'and. beyond theproperty-boundary70years' in" .the"" "future:. -.-....(The ground water flow"and solute, transport ffi'6/del that was used to,.,simulate- themigration, of. vinyl..cjiloride is: de-scribed in detail in the PhaseIII Report . [Revision 01 / "Nc m er J a'.lJ/ PMred ..by IT.) Inaddition, cOn'tamlnant. c6nc'entra 'tio"n ''tnat"" a;y occur in groundwater, as -a -:resultT' of^leachihg/from subsurface, "soils and wasteswere.:con-s'ldere.d-- in' the" Risk Assessment.

Potential routes of."exposure .td 'constituents: 'in ground water are--discussed in .Section" "67271,2, above.. " "A 'h'umher of . assumptions areused: to...-calculate."t'he-dose for "each, exposure; route since it is 'seldom possible , to .measure a specific dose:;"i/.The. followingassumptions -..were.. used""""t6 "estimate \exposure to "ground waterconstituents:- ..-.--.. - - - _ . . - . . . . . . . . - . • - - - - - - • - , • .-.---.-:......

• Receptors'/include a :3( i"lp|g:r m/.Ckg)/child ingesting 1.0liter.. p"er. "day" l"L/day)""and"a "70-kg 'adult/Ingesting 2.0LZda'y every day .for; 17'and .3.0 _yea.r,s,r respectively.Showering'ls'•assumed "to, dcciir.'dally, "with adult and childreceptors—b-eing exposed for:.12 " minutes /per day.

Inhalation .rates' .of. .adult' and child receptors are' 10

18

A R - 3 1 1665

liters per minute (L/min) and 13 L/mi'n/ respectively.

* The total skin surface area available-.for contact duringshowering or bathing for.a child is 10,455 squarecentimeters jcm2) and the total surface area.-for an . adultis 19,400 cm2.

Dermal permeability coefficient factors presented inEPA's -Interim Guidance for" Dermal Exposure .Assessment,Review Draft (March 1991), were, used to estimate the massof organic compounds transferred .through'the skin.

* It was assumed that significant -levels of heavy metalswould not be dermally absorbed from water o"n~'the skinsurface. .

Two mathematical models were utilized in the exposure..assessmentfor the ground water pathway. The shower model developed by'Foster and Chrostowski (1986)2 was used, to estimate.,a sjrowerdose, expressed as mg/kg per shower. The., contaminant"- "concentrations that may occur in ground water as a result ofleaching from subsurface soils and wastes.were derived using themodel described by Summers, et. al. .(.IB'80) . / " "

Surface Soil Pathway. Direct contact with and incidentalingestion of soil, and inhalation of wind-borne soil. . , .particulates, were evaluated as potential routes of.exposure fora child or adolescent trespasser visiting the area .during •-weekends and other nonschool periods and for an adult droppingoff refuse at the Transfer Station. inhalation of wind-bornesoil particulates was also evaluated as. an exposure route forindividuals residing northeast of the Site on Firetower^Road.

The following assumptions were used to estimate current exposurefrom potential contact with surface soil:.. . "... ..._..

The exposure frequency for' both an a~dult and child ..exposed off-site to windblown dust was assumed to be 350 .days per year . (days/yr) . The child trespasser exposurefrequency was assumed to be four times a month for_ninemonths, or 36 days/yr. The adult visitation frequencyfor refuse drop off was assumed to' be once_:a_ week, or 52days/yr.

• The off-site exposure duration was assumed to be 3-Q. and"17 years for an adult and child, respectively. Theexposure duration for a child six to fourteen years old

See the List of References appended to this RQD_,

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trespassing" "On-sITe". was" assumed/to/be nine years". "

The soil ingestlo /ra'te.i-iQr/ children .and - adults was.assumed .to .be..100-..milligrams/ per '.day (mg/day) .

- . * It was .as"s'u'med". that one hundred percent of the chemical -adsorbed .on. soil...particles" would ..be absorbed by theadult's-or child's gastrointestinal tract.

• The .wind, direction, was assumed to be originating .out of ..the southwest-,lQ..G-.per.c:ent .of/the time, i.e., blowing..toward homes': clo,sest".to"~..th.e. Site,-on Firet.ower Road,

The- inhalation "rate was assuftied to be. 2_0. cubic meters .per'day '(m3/day)"" fo"r;;"an'" a'dult."--a"hd 19,2'"m3/day for a" child.

It was""as_su:me"d that 10-0 percent of the. constituents ofsoil -pa:r""tic.uiates-are .absorbed .following inhalation.

* The skin surface area:";;a'val_lable- for/contact was assumedto. be,4, 440 cm2 for . a/child"- (the estimated surface-area.of the-.hands, -arms' and legs) : and 2", 000 cm2 for an adult{the estimated surface, .area of 'the., -forearms arid hands) .

• ' The s'Oil adherence f actor .wa? "a"s""sume_d- to be .1.45milligrams per :ggua;re" c'entimeter .per" day (mg/cm2/day) .

It was assr"um"ea"""""'th"at one percent of .the cadmium in soil isdermal 1 y absorbed.. No other soil constituents wereassumerd tQ,.-he available .for""dermal absorption.

Three, 'al'r . moaels ..were used to ..determine particulate'concentrations" at/the"."Site:/ .a" Xoii /emissiott .m6del.-Lto'. determineparticulars ..em:is_sloh" rates "from "wind ..erosibri' (0.. S . EPA, 1984) ; abox model- to. e .timate.."qn>:si;t"e. e xp qsij e/tli .na.a.h, et. .al., 1982);and .a' G'aussiah" isp rsTon/ rEiddeJT.. o/.4s"."timate/Qf.f.-site- migration ofsoil particulates = [Tu,rner, 1970"). /

Subsurface.Soil Pathway. Direct routes -of^exposure"to subsurfacesoils and -wastes; ""(derMal contact, Incidental" Ingestion andInhalation) were ,not considered slrice'- np/"exc aya.tl_o""h_..or, subs.urf ace-disturbance "•'"£s'.e petcted ""tG'" occalr"*a"t/the. Site." However, as notedabove, the model described., by Summers, "et' _al v, was .used- toestimate-the concen'trati-on . "6.f -co'ntaminants. tha. . would .occur inground water- a3"J""a ""r sult//6±"''l'e"a"cnlng from subsurface soils andwastes..'" 'Exp"ds'ure":/t(5/:the leachat.e.-contaminat'ed ground water, wasevaluated in""the Risk Assessment, based "on "the assumptionsoutlined above. f or -the..ground water -pathway.

Sediments Pathway. Dira:Ct. cont_a.ct.. with...sediments, arid subsequent

20

flR3t1667

incidental ingestion were considered potential routes, of exposurefor a child trespassing on the Site. The following'assumptions"were used in evaluating a child's exposure for .the...trespasserscenario: . . . . . . .

• The skin surface area available for contact:".with the seepand settling basin sediments was assumed tov.be 4,440 cm2(the estimated surface.area of .the arms, hands and legs).

The skin surface area available.for contact iwith thesurface-water sediments was assumed to be 1,800 "cm2 (theestimated surface area of the. hands, feet and lower .legs).

Other exposure.parameters, including exposure;frequency andduration, and ingestion and absorption rates, were assumed to .have the same values as the parameters.jus-.ed in the scenario-Xor.-..exposure of a child trespasser to surface soils.

Surface Hater Pathway. Direct contact ..with surf ace,.waterconstituents during wading in the unnamed creek and trespassingon the landfill property were considered as potential routes of""exposure for a child trespasser. Ingestion of potentiallycontaminated fish was not considered.since .the creek has alimited ability tor support recreational fishing due to itsshallow depth. The following exposure factors were used inevaluating the child's, exposure in the surface water .exposurescenario; . .

The skin 'surface area available for contact with surfacewater was assumed to be 1,80.0 cm2 (the estimated. surf ace-area of the hands, feet and lower legs).

Dermal permeability coefficient factors presented inEPA's Interim Guidance for Itermai. .Exposure 'Assessment,Review Draft (March 1991) , were' used .to estimate the massof organic contaminants transferred through the skin.

It was assumed that significant levels.- of -heavy metals _..would not be dermally absorbed from surface, water.

The frequency and duration of exposure ..to surface water wereassumed to be the same as the frequency and duration, of exposure''of a child trespasser to surf ace .soils. . :. ' „.. . 1 _'__.

6.2.1.4 Quanta.•fca'tipp-, of Exposure

The reasonable maximum exposure (RME) concentration, was..used .to .estimate the level of exposure to chemicals of,potential concern.The RME concentration Is defined as. -the upper 95th percent

21

AR3! 1668

confidence : limitj-on tfie" "arithmetic mean 'oi/'tne analytical .datafor~~ea'ch chemical of "potential concern". For, some chemicals, thecalculated uppers9.5th""percen/t 'confidence "level" exceeded themaximum" conce"ntratl..o.n...fo.und""inH" a particular-medium. In thosecases, the -expo-sure" "point" cnnc.eLn.tration was'set equal tb themaximum detected concentration';

ContamihateB. "ground";wa,ter/:."wa s"The"/only medium at the Site foundto pose~a"threat /to"human health. The chemicals found in groundwater samples- cQllected^fr.qm."Site monitoring", wells a_nd the. RMEvalues for the cHemic.als"are" presented' in Table. 1. The chemicalsfound in. ground "water /samples /"collected from residential, wellsand the RME values for/tne'".c.hemica;ls.:are presented in Table 2. . "The"concentrations-of contaminants predicted to occur in groundwater as-:a" rgslilf: o'-f-;potential 'fuTulrl^Teachlng'f rom Cell B/C'wastes is presented in Table :3:/" ..:,-../_././../.;_..

Although ground =wa:ter is :.the.._pniy medium at. .the Site thatcontains contaminants at level's _ tha't would", result, in, .unacceptablelevels-of/ris'k to.""exVos'e 'human populations', 'all of the chemicalswith available toxic! t"y_ factor's Jjv^each o"f; the environmental-media evaluated' a~"t": the" ""Site "were", used/to"."estimate'potentialhealth .risJcs in ..the Risk Assessment. Exposure', scenarios for ...eachpathway .were evaluated".,to.ge.ther with the exposure pointconcentrations" to "derive: "intakes jexpress.ed as., mg/day) for .eachpopulation subgroup. "By "dividing" the. intake" value/by theappropriate .body weight, a dose "expressed in milligrams of"contaminant-per.-kilogram of/boo!y_ weight, per''day (mg./kg/day) wasdetermined for" ergch jige- 'gr.oup/ """T"his_ dos.e:.! ; referred" to as thech r on lei. dally "intake'. ("GDI) . The GDI ""values/for each exposurepathway are:, presented.ln-"Appendix N of..the. RI Report.3

6.2.2 Toxicity Assessment

A toxicity evalua"tlon":of/the chemicals present at the Site was •conducted in or derate:" Identify relevant/ carcinogenic potencyfactors'/and chronic. ,reference: doses : aVainW.Vhi'ch daily intake.levels-could be . compared.-" V"----~ "i --——-_-—---. -"•-•--•--

Cancer . slope .f actor^/fCSFs) '.have been" developed -by EPA'.s.Carcinogehlc.. Assessment' "Group "'for :es/£lma£rng" excess.' lifetimecancer'risJcs—assD'CiB'ted .with exposure to ,potentially carcinogenic-chemicals. Cancer" siop'e-"factbrsVare 'derived'from' the results of

The. oral" reference jlos.e.. (RfD) "'for- manganese "was revised .subs_e.quent to. the preparation" of the..RI .Report. Therefore, theCDr..:values for Mh"gane ; /A:E fid.ix,N"/o£,.t]i .Rr'Report do not . .reflect .the revised/RfD. for manganese.-; The.'gummary riskcalculations/. preseh'teByin' Tables 6" thirbugH ~8"/"of""-tnis, ROD doreflect the" .revised Rfb for .ULangaries-e/"- ;;i -.//•' ' ''

22

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human epidemiologlcal studies or chronic animal bioassays towhich animal-to-human extrapolation and uncertainty factors havebeen applied. CSFs, which are expressed, in units of,.. . . . .(mg/kg/day)"1, are multiplied by the estimated chronic-daily "intake of a potential carcinogen, expressed in mg/kg/day, to:provide an upper bound estimate of the excess.lifetime cancerrisk associated with exposure at that intake level. The term"upper bound" reflects the conservative, estimate of the risks.calculated from the CSF. Use of this approach""makesunderestimation of the actual cancer risk highly unlikely. CSFs""for contaminants of potential concern at the Site whichcontribute to the carcinogenic risk are presented in Table 4. .

Table 4 also reflects the degree of confidence .in the: data usedto determine that the chemical is a human carcinogen. EPAtoxicologists recognize that the risk associated with a knownhuman carcinogen, based on epidemiological studies, should beevaluated differently from the risk attributed to a" chemical thatcauses tumor growth in laboratory animals. Each carcinogen is ...assigned to a group according to the quality and quantity of" .evidence for carcinogenicity in humans and nonhuman animals. Thedefinitions of Cancer Groups A through E are. presented in Table.. .5.

Reference doses (RfDs) have been developed by EPA for" Indicatingthe potential for adverse noncancer health effects from exposureto toxic chemicals. The model used ,to develop RfDs" is based onthe assumption that threshold levels exist for certain toxiceffects. Two chronic toxicity parameters are used to establishRfDs: the lowest-observed-adverse^-effeet. level (LOAEL) , and theno-observed-adverse-effect level (NOAEL")"* The LOAEL is -thelowest exposure level at which there are statisticallysignificant increases in adverse effects in ah exposed animalpopulation. The NOAEL is the highest exposure, level .at .whichthere are no demonstrated adverse...effects- in an exposed animalpopulation. Uncertainty factors are applied to the NOAELs orLO&ELs to adjust for data limitations and for~di"ffererices betweenthe exposure conditions of laboratory animals and human exposuresituations. The .resulting RfD, expressed in units "of mg/kg/day,can be. compared to the estimated human; intakes of chemicals .fromenvironmental media In order to evaluate the potential foradverse health effects. The RfDs.for..the contaminants ofpotential concern at ..the Woodlawn Landfill Site are, presented inTable 4.

6.2.3 Risk Characterization

The risk characterization combines'the dose (or GDI), and thetoxicity value to generate a numerical value for risk. There areseveral differences between the approach used to describe riskfor carcinogens and noncarcinogens. B-Qth approaches are

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summarized below.

6.2.3.1 Carcinogenic Risks

F.o-r carclh"6f e sTi's'ks .. are estimated:/ as the .incremental ". .. .probability o'f. an/ Individual.. developing cancer over a lifetime asa result of -..expbs\ire/td' "t.he/":ckr=e e ea.;/:ExS:ess lifetimecarcinogenic "risk" ",is calculatea-by'multiplying the. dose (GDI) bythe .. cancer ,.s.lx3pe""fa"ct6r;::/;i"circln.ogena:cJ'Hi'k ' estimates for eachchemical and each /exposure pathway may be ..added together todetermine the. ag regate, rAS associated . with exposure'ta multiplecontaminants in multiple 'media. These risks; are/probabilitiesthat. ar.e. -generally .expressed/ in ..scientific "nbtation (e.g. ,1 X 10. ..4. -An excess", lifetime" /;carcinb'genia jri .k of."'l X 10"6indicates; that, as/a plauslble7.uppe"r: Found," an"' individual has aone- in. one'.'million chance'" of developing cancer "/as a 'result ofexpOsure_-1Xol^ite-r:re"lat,ed_icontartrinants over: a; Tp-year -lifetimeunder. .the. Speeiiic/ext5dsilre/c3niiiti6hs"at 'tfie Site.""

Table 6.;;p_fe""sS;ts ^ ^ estimatesfor :the. exposure:' Q"r:aaultr and". child receptors to ground water.containing all of-,: the .c.hT.eTm.ical/_const;ituents .'that' were found ineach of -.13 residential, wells, sampled' during 'the'RI. The totalcancer,YrisJc...asso_clate.cJ with., exposure to' residential well watervia each of ,. the. identified exposure .rentes (ingestion, Inhalationand dermal contact) -"is: l.:.€ X"1*T4 for adults and 1.0 X ID"4 forchildren. , The majority of. the/risk is attributed to beryllium,arsenic; :and vinyl chloride. -However, as" fiot,e4 in Section 5 2 2 ' 'above, the beryllium/detected in the .domestic, well samples may bethe result of, aborj qr . co,n_taffiln'ation../ .When "beryllium iseliminated- froirrthe ;risk" calculations, -arseiTlc and vinyl chloridecontribute; 9.0, and. 8. 3 percent, " fesgfctlyeiy of the total adultcancer risk of":4 ._e..X'._l.D :,as:sx5cTa±M with exposure 'to residentialwell .water.' ' •"" - • - • - = - . - ... - -• -.---:— —-•- : -:- v™

The.total, cancer"risks for,a child feceptor/exposed to surfaceso-rls. in., the •generkl-Iandfill...area":Jl/:a x "10"6). .and. for adult andchild -recept:iors_ -b_gS.d."Jt rMr£ace"soiis . of /"the former drain'field (3.5. X 10" and 1.7 X 10"6, respectively) fall within EPA's"target risk range "of,-:'l X 10"6 to 1 x 10" -.., .The total cancer riskasso-ciated with exposure tQ'.;eac.h of /the -other environmental mediaevaluated1at^the ...Site ls/.les"s--than" I/X-IO^6." Summary risk tablesi0:r-.ea £1_.9f the media evaluated . in ..the Risk" "Assessment can befound In the .RX Report. . ~: .; • ._."'"" ..v. ."..._":..,..;.":......._•". • . ..

Table, ./provides "a"summary"o;f tn;e"toiar:.cancer'"risk estimatesthat are based-on. potential current -exposure.!.of adult and childreceptors _to Site.-ccffltaminants'' through _alX of the pathways(ground . water,.- surface; :'w;a g:r-7r:ie;dliae;n exceptdrain field surface' soils}' thai :were :evaluated in the RiskAssessment,.: A comparison of the"risk.estimates in'Tables 6 and 7

24

f l R 3 l 167

underscores the fact that contaminated .ground water Is. the ._..primary medium of concern at the Site. . . . . . . .

As discussed above, the risks associated with potential futureexposure -to Site contaminants were evaluated in addition to the .risks associated with current exposure. Table.8.presents, asummary of carcinogenic risk estimates for exposure-jor" a'dult andchild receptors to contaminated ground water for threehypothetical future use scenarios: (.1) . exposure to contaminantscurrently present in ground 'water beneath the landfill property,assuming a public water supply well Is placed.in the center _of _..the contaminant - plume (existing conditions scenario); (2)exposure to ground water contaminated with, the"highest levels, ofvinyl chloride that, with the aid of a model, were, predicted, to•".occur in the aquifer beneath the landfill.property {on-sitej and.beyond the property boundary (off-site) .70' years In 'the future, "assuming water supply wells are placed in the portions of theaquifer that are expected to be most highly contaminated at .thattime (modeled scenario); and (3} exposure, to... ground watercontaining levels of contaminants that were" predicted to.occur inground water beneath the landfill property as a result of futureleaching from Cell B/C wastes, assuming a water supply well-Isplaced on the landfill property in the leachat.e-contaminatedground water (leachate scenario) .'

The future cancer risks for adult.and child receptors potentiallyexposed to the existing concentrations of the .chemicals in theaquifer immediately below the landfill" are ..5.8 X 1CT3, and 4.0 X10~3, respectively. The chemicals in on-site ground water thatcontribute most to this total cancer. risk, are. vinyl chloride,benzo(a)pyrene, benzo(b)fluoranthene, arsenic-and 1,2-dichloroethane. Vinyl chloride and benzo(a)pyrene represent 53_and 35 percent/ respectively, of the total adult cancer:risk of__.5.3 X 10"3.

The future cancer risks for .adult receptors exposed to groundwater containing the highest levels of. vinyl chloride that werepredicted to occur, in the aquifer 7CLyears in the future are 1". 5X 10"2 for on-site receptors and l._8 X 10~3 for" off-site .receptors.

The cancer risks associated with potential future exposure to on-site leachate-contaminated ground water are -7.«.8 X 1CT"2 for -ahadult receptor and 5.8 X 10 for a .child., receptor.*:,- .Nearly 100.percent of the risk is attributed to "vinyl chloride,.-.. L,_ „ _.

6.2.3.2 Koncarcinogenie Risks

The potential for. adverse noncarcinogenic health effects a§_ aresult of exposure to.a single contaminant In a single medium isexpressed as the hazard quotient (HQ), or the ratio of £he.

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estimated- daily -intake.of a'contaminant in 'a given medium to the.contaminant '-S..refe-re'n:c.e.:rd6s/e/ --"The ._hazard index .(HI) is obtainedby adding the HQs for"" all of- the .contaminants in a. medium or. ..across:/all .media to. which a given population may reasonably be.exposed. The HI provides' a. us"e:f.ul/referv"ej:Laej point 'for .gauging 'the potential -sl nlTI ah ^ contaminant ...exposureswithin a single'"medium"."or across; ;m;e;dia. " Hi" values .less than or. -equal. t.o.a.:.Q..=lndicifa-te/"that".;iif etime.;expo;s~ure has "limitedpotential", .f or _cau;sing;"a adver"s'e""/e/f±e"c"t/lri./s populations'.HI values "greater-, than 1..0 show that acceptable, levels of intake

have been exceeded. --

Table... £,. presents thej5ThVpnic_hazard.in.d.eK-^.estimates for. exposureof. adult and'child receptors'.-to. ground ,wa.ter .containingcontaminants --found In residential wells/.adjacent .to the Site.The .HI valuesTliXceeUed/i.O -for/botti children (2.6} 'and. adults(2.3.7 .""Manganese-is" the'"cojitairiinant :.wl"th "the highestnoncarcinoge'rTic. rr"i"sk for-this pathway, with a HQ of.2.0 forchildren a"ri"d 1.8 for adults.,......... . .... .".'." .""..--..-

The HI values" "assuc'ia'.ted with -exposure'.to contaminants, in theother .environmental media-evaluated at- the/Site.. are less thanl-.-0-,-"-indi-.cating that .lifetime exposure to", .these me.dia is notexpected to.,.result in/adverse honcar.elnogehlc health .effects inthe. .expose'd- popula"ti"bns-".V"..::/"Summary/""rrs'.k'/tables" for .each of themedia evaluated in the Risk Assessment .are Included in the RIReport."." " ~":_::" v ="-frrr=r"'.;;:" ; ':":::.:.;... :, . •..:.':. ".." - -: - - - •

Table 7 presents; ""a""" "syui ^ index estimatesfior ..exposure "'o;r ad"ult and child' receptors/to all of thecontaminated media'- (ground "water, ' surface/ w/aTer, ' sediments andsurface-TSoilsJexee tr irain field/surface/:sb"lls) that wereevaluated in tji_e: s/k;j\ssessment,v _/_$ cpmgarlson .of the. HI valuesin Tables"."" 6 .-.arrd..7 "again :de"m6nstrat"e3""tna"t contaminated, groundwat.er;,.is;.Jihe.,jnedium of "concern at the .Site. - . - ,

Table 8 presents^ a ummary of' the /chronic, "hazard index estimatesfor exposure "of.'/atlult and child:'receptors 'to contaminated groundwater ....for., two5,,.of'."the ny£otHetical\"fut:ure -use scenarios' describedin Section 6."-'2,3-i; "above/ """("Non'carcino-genic;, risks "were notassess --for.-'jiJie health•e.ffeet, S.or-vinyl" chl'ori.de" is .negligible" compared to the cancerrisk., and, ' there'for:ei,-in"O"~fef:e:rCn''c?"e;";dQs.:e:...ls"r ~for vinylchloride.) ~" "" ' " . . . . . . -— ---

•The. HI...values.:for..child" and adurt/. recepto s otentially exposedto. .the. existiS'g cohc-en/ the aquifer 'Immediately below/the.landfill - re//5"j..;an"d 5fl," respectively.Manganese ls^"tihev-"pTOtaminant, ."with the .highest, noncarclnogenlcrisk for this potential,..future."pathway, with a HQ of 56 farchildren and""^8 ..for adults./-. ' ." ._....-,.:......:..- / .....

26

AR3!1673

The HI values associated with potential future'exposure to on- -,site leachate-contamlnated ground water are-.les-S-.than...l..O. '. .

6.3 Environmental Risk Assessment

Potential risks to nonhuman biological receptors were evaluated ...in the Ecological Risk Assessment which is included in the RIReport.

No critical habitats, endangered species.,or endangered specieshabitats have been identified in the. Site area. However,wetlands occupy limited areas of the Site as discussed in Section5.1, above. In "addition, a tributary of Basin Run crosses thesouthern end of the Site.

As discussed in Section 5.2.7, above, several.metals-were found"in downstream surface water samples collected from the unnamedcreek that flows across the Site, Levels of.aluminum, copper, •lead and silver were found to exceed .federal ambient .water "quality criteria for the protection of aquatic, life.* '."

Levels of mercury found in soil above the former drain field of—'the Transfer Station septic system "exceed the 1 ntg/kg soil...criterion that EPA has determined is protective of ...ecological .receptors at the Site, and may cause sublethal effects in area. ...birds that feed on exposed earthworms.

Levels of cadmium and zinc found in on-site seep sediments also -exceed criteria that EPA has determined are protective ofecological receptors at the Site. . The levels of cadmium found 1'nthe sediments may cause sublethal. effects/in area" "predators "as "a"result of.bioaccumulation. Levels of zinc/present In the seepsediments may inhibit plant growth.

6.4 Conclusion

Actual or threatened releases of hazardous substances from thisSite, if not addressed by implementing the response actionselected in this ROD, may present an imminent and substantialendangerment to public health, welfare, or the environment.--

7.0 REMEDIAL OBJECTIVES AHD CLEANUP LEVELS

The overall remedial objectives for the Site -are: (1) to. preventexposure to contaminated ground water;- (2) to prevent migrationof contaminants from the landfill.and PVC sludge disposal cells.to ground water and surface water"; (3) to. restore .ground water-toits beneficial use; (4) to prevent exposure to.the contents ofthe landfill and the PVC sludge disposal cells, arid, contaminatedsoils and sediments; and (5) to control landfill ga~s"to"."ensure

27.

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protection" of :human health and" the. environment . - .' .

7-1 Remedial Obiectives and Cleanup Levels for Ground Water

The Risk " Asses" men t-.lnaca-;te"s ;that_t-!ae ca.rilo.gn.ic -andnoncarca-ritigenTc" rlslcs "/ass~-ociat:e.d/with Jexpqstire to' contaminatedground water/ r: the. Slte. exceed "acceptable levels, and thereforewarrant remedial act:ioa;/td/]clean up ground", water at "the- Site.Ordinarily ,__ "M^sandjjhori^ Level .'Goals_ _ ^(MCLGs). w"bulct."be.. us-ed".". as; .cleanup levels . for./ ground water.- Atthis Site, however/' because.. , there. ;are r '.multiple -contaminants, thecumulative, -carcinc-J e/nlc"" risk' .associated with . MCLs' for . those ' " .contaminants exceeds J--X i(T4...."Jn/ .addition,' ; the hazard index'associated" wTtn~~"MCLs" and MCLGs/: for ,"3ite ground/ water contaminantsis greater "than 1 . 0 . :. Under, such ..circumstances, risk-, or health-based levels are -.us"e;d _.tg.__4e"vel_op_'cleanup'";ievel's . ''' Risk-basedcleanup levels are lev.eis//t"hat/would result-In a cumulativecarcinp^enic^risk/wltHIn-EPA's target ,ris'k range of 1..X 10"4 .to1 X 10.,; health-ba-sed,. cleanup levels, correspond to a. HI of" 1.0. 'or .less-* -: Ocd'aSibnally, - 'calculated^, risk-/ and" health-basedconcentrations.: are, focinH/.JiQ/.".|5"e//io"w"e£_-than ..background levels , orbelow. the. levels -that can actually be . detected .or accuratelymeasare±t--iri:The laboratory. " ; .jWheh ' these situations arise, EPA mayalso "take background conditions, -or practical Quantitation Limitsand Instrument : Detection".. X;iinI:ts;,;In"tb/accoUn.t when establishingcleanup levels 7 """ "• - '.•': :.'':.::.-.:-" ... ;...T .„.. — :,.. -.- -•.•• .. ' '

The". following- remedial- objectives-and cleanup levels weredeveloped f or grsund" water"" at""E_he "Site' based/on/: theconsiderati'o.n""S-"-b"Stl£ned"" above":

1. Prevent" exposure itp:..g;ro'un'd wa"t,er._tiia.t cpntains Site-related -cdn amlnants. at qpnCe:n?trati.Qns ,;fchat exceed thecleanup levels'""presented "In Tables .9\'_~and. .10, until theground water .:cleanup levels" are a'chi'eved. '

2. Remediate, gr.o.nnd water in. the areai-of .."attainment4 sothat: (a) . the .levels._,a"f. contaminants'with carcinogenic' •'health effects .cLb . no't exceed the . grpun'd"1 water.'" cleanup levelspresented in. Table "9";" and ..(bj the levels of contaminantswith' noncarpino:gehlc'/'health "effects (presented In Table,. 10). 'do :,.n.o.t.exceed MCLs, Lh6n-zerb "MCL(S"sV-~or'"levels that .wouldresult in an "ag'grecfate ;H1_ reater^than 1.0, . As noted inTables".5- and 1-0, EP"A'_wiiI take.'bac.kgrp.un4. levels of .arsenicand man"g"anes"g™"intb:;""ac.count in determining whether the.remediation objectives"have been, achieved.

' - • ' • ' '

The are/a-:o;£:-a/t;tai3menV,-;i ; -e_flne.'d"/a.s;:thi outside thedary or any w steoremalnihg."/in' pTace.'Ep to "and including the

boundary of the_contaTainant plume/ " "' ""^"- "

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A R 3 I T675

7 .2 Remedial Objectives and Cleanup Levels for Wastes

Some form of control of the wastes in PVC sludge disposal CellB/C {and Cell A, If found) is necessary in" order -to. ensure that"leachate generation does not. result in .an' exceedance of theground water cleanup levels^ .-In" order to -evaluate, treatmentoptions for this material, a cleanup level' was developed, forthese wastes based on the Summers model. The results of" theSummers model indicated that technologies for treatment of thewaste must meet a treatment standard (cleanup level)" "of 7.7micrograms of vinyl chloride per kilogram of waste- in order Ito ~ .sufficiently" reduce the concentration of contaminants in/ theleachate that could be derived from the PVC sludge.Alternatively, waste containment technologies must be designed tominimize" the infiltration of rainwater and resulting "leachategeneration.

7 -3 Remedial Obnectivos and Cleanup Levels for Soils

Levels of mercury in the soils above the former drain field ofthe Transfer Station septic system are .above normal backgroundlevels and may provide an opportunity for. mercury to enter thefood chain via exposure of soil organisms to the. contaminate.dsoils. EPA has determined that a soil mercury concentration of / -1 mg/kg Is the cleanup level that would be protective ofecological receptors at this Site. Alternatively,, wastecontainment technologies must be designed to prevent .'exposure o±.ecological receptors to. soils contaminated with mercury in excesso f this level. „ . . . . . .

8.0 PESCRZPTIOH OF ALTERNATIVES

The Feasibility Study prepared by IT. .(April 1993) evaluated sixalternatives to address the risks posed- by current and potentialfuture exposure to contaminants at the Woodlawn Landfill Site.Alternative 1 provides no remediation, monitoring or "controls,but was retained as a baseline 'for comparison with otheralternatives. Alternatives 2 and 3 are" considered .limited actionsince they include monitoring, Institutional -.controls andmeasures to eliminate exposure to .contaminated ground water and,in the case of Alternative 3, a landf ill / cap "in order to_ complywith State landfill closure, requirements . Alternative 4 providesactive remediation of contaminated ground water. Alternatives .5and 6 offer two options, in addition to capping, for addressingPVC sludge disposal Cell B/C. and Cell A, if found: on-site,treatment and off -site disposal, respectively.

COMMON

Alternatives 2 through 6, which are described 'in greater detail

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below, include several corrimo'n /"element's. .7 First," each' of thesealternatives -proVides.. fqr cMXtr:uct;ip ot/"a'Jpe"rime.ter securityfence. 'around, the landf iil'-property boundary in order to. .securethe, Slt.ei:irjDj ./una:u'thorize~'d racces's.""mn"d usage. "".

Second, each :of 'Alt,er"nat:l"v"e"s" ""2/--t.nr/QAagh '6 'calls, for the ...institution of/_landfill.:pr"ope"r"t:y!'"de.e"d. restrictions" and area : "ground wa.t.er ..:use..:.r:es""tricti"b"ns'.BS '"nejc:e_sVs''a;r|y""t'o/prevent exposure tocontaminated ground water ./.and; . wastes/. ah"o!/ to.; insure that the ,alter native^ may be eff.ecti.vely "Implemented'. """

Third, "each of Alt'erna't.i"ve_s.y2 rough .6. .includes ..regularmonitoring 6F " d :" aT r 1|7 naia_e" creek, and "landfill gas .The monitoring; £ rt>5'!r/a~_ms"/ ;^ activities : "installation" of "three or -four .new monitoring wells around theperimeter.,, of , ±he landfill; "quarterly 'sampling of 'nine to elevenmonitoring, wells /and six -domestic. /wells "..during, the .post-construction" reme la'tiori 'phase; "'quarterly sampling of surface- - ".water, ..and sediments -from' four or :five/loc"ations""'in the unnamedcreek during the .pos ric n tM it. on r.e di t pn" phase;installation of a "hetwarJc^of .nested- sgil-gas .. probes atapproximately;" 5 3/: location's" "ar.6 d/gie7 perimeter of the landfill ;and -quarterly collecTion .or-' gal; s"a les'/::from'"ea'ch" of .the soil-gasprobes. The-. moni.ta.ring"c'ds""ts - a'ssbc'iS'te 'wiEh" each alternative J.are based On ;'thes.e:,a;ss_umptlo"hs i .//;/E;i..nal ..de.termination of thespecific... number.' and location"-of 'monitoring |5oi.rlts, ' the frequencyand duration of .sampling,' aha": the" 'analytical parameters andmethods to- be include_d_ in the :monitorlng""p"rorgram, will be made byEPA, in cbhsul tatibn:. with. .MDE, 5 during the^remedial' .design and,as appropriate/ during:."lmplementa'tion of- the "selected remedy.

Fourth, each of Alternatives 2. "through" "6 provide -for_....an alternatewater: "supply at"":"resl iences where Site-related . contaminants aredetermined to'-be^p-resent. in" "domestic .'well: "water." .at 'concentrationsthat. exceed the ground water cleanup levels__presented in Tables 9-and 10.' 'The- cas'.ts ..for. main tainlng"' the" well water .treatmentsystem at. parcel. 3.5.9,/.w;e_ """i;n.cXvLded /in" the.":cost -figures forAlternatives" "-'S Kfoagn" ~6, ..However, the costs, .for. installationand maintenance ~ofT additional treatment systems were not.. includedin the cost e-itimatesv..-'---. ------- -V--.""-~T -. ./:>.- =~-.--;- •= -...n f . -'-^ '-.-.- -.-..

Finally, Alternatives 2-th'rough. 6 provide :for interim' monitoring

In a"ccorfaanfie"v^Ltfi 40 C.F.R. .§. .306\.Sl5 ft) (3) in'Subpart F.ofthe NCP, the. phrase-,'-'EPA, in consultation''tilt'h MDE" when used inthis-ROD means." that-EPA (the lead agency) shall provide MDE (.the . :support-agency) an; ;pgparturi~ity To "review" and coitiment,/on the. . ...remedial, design arid any' proposed -"determinations 'on potentialapplicable. or:x levaiit and appropriate "requirements '-(ARARs) orcriteria, a'dviso±"fesirdxl-5l5uTa;ahc:e" ltb'~be -considered" (TBCs) .

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of select residential wells. Because of._the. potential publichealth risk posed by contaminated ground water ;at the^Site, EPArequired annual monitoring of seven residential wells to'beginprior to the post-construction remediation..phase (interimmonitoring). Interim monitoring began in May of 1993/and* wouldcontinue under "Alternatives 4 ...through .6 until .the post- =construction quarterly ground water monitoring .program begins.If determined to be necessary by.EPA, in consultation with MDE,the number and location of residential wells in the interim /monitoring program and the frequency of monitoring ..ghall bemodified. The costs for the interim^monitoring program were notincluded in the cost figures for Alternative 2'through 6.

COST EVALUATION:

The cost evaluation of each alternative includes consideration ofcapital costs and annual operation and maintenance costs,(O&M).A present worth analysis is also included, allowing all remedialaction alternatives to be compared on the basis of a. single....figure. A discount factor.of'ten percent and a zero percentinflation factor were used in the analysis and a 30-"yearmonitoring and maintenance period was. assumed for cost estimatingpurposes. All costs and implementation time frames .provided forthe alternatives below are estimates .and should be used f or^ - ;,-.-.comparative.purposes only. The actual .duration"of the monitoringand maintenance period will be determined.by EPA,'in consultationwith MDE, based on the results of.environmental monitoring andstatutory five-year reviews.

The following Is a brief summary of each of the alternatives.evaluated for remediation of the Site. " """.".

Alternative 1: No Action

Capital Costs: 0Annual O&M Costs: 0.Present Worth: 0Years to Implement: 0

The NCP requires that the "no action" alternative be ..evaluated atevery site as a baseline for comparison with other.alternatives.This alternative provides no remediation (other than what mightoccur through naturally-occurring processes), monitoring or.security activities at the Site. .This alternative .wpuld notprevent or eliminate exposure to contaminated .ground water, inresidential wells and would allow continued migration ofcontaminants from source areas into ground water and surfacewater.

Alternative 2: Monitoring, Deed and Ground Water OseRestrictions (Institutional Controls),

31

flR3! 1678

Perimeter Fencing, Treatment at ImpactedResidential Wells

Capita_l_."Costs : "-----"" " 5"5'62 ,"000.::"'Annual O&fyTCostsY"" -TV. $514'J/000'"""Present Worth:' "" $4,436, O'OOYears- to implement^-" -3"

In Alternative- 2-,- deed...restrictions would, be. -implemented to limitthe future use 'raTTd; "development of. the "landfill property. Inaddition, " ro;unol_w e ,l:[ \ :r &tr.ictipns/. which are currently ineffect, would continue, to .be "enforced .and. modified as necessaryto .prevent e p-b's"''U"r~e rtb/".::cQnrainIhated ground-.water, and to ensuretha.t_the..-s.elect-ed remedy_could__ be effectively implemented.A security .'f nc/e'-wpurd . be ereqted^arqund^the, perimeter of thelandfill ""property bo:un^aryjparcel ;267), excluding the Transfer ""Station" b.uiloliji jand ;rj ^ lh" birder" to secure theSite, against:, unauthorized .access.' ..Bare, "areas ;of.the landfill' 'surface..'would be revegeta"te~d in._;order. to ,.facilitate maintenanceof, the. exis.tin"g/lah.afi"ll/"'c"o"v'e'r/materiai. /" !~"'~~ "J~ f .""" " '

Alternative/..2 .Inclu"3e_s//ri6 ;a/ction .tp . rerae.dllaie ground water or toeliminate -fu-tur-e /.-cant mina'tion'/Qf r tiftd;/waferT "Constituents of/wastes and soils 'would continue; to leach into .ground water, = - "-"contaminant levels/in"the ground "wate^ would .continue 'to. exceedthe cleanup levels,--and" contami"nated""""gr"ound;; water would, continueto migrate downgradient. . Howe_ver, groundwater and streamsampling and analysis would- be. conducted until the ground watercontaminant c.ojrcentr at ions' er$/'"r_ ^ levels, as are-suit o.f/.natural1"att'.enuatio'nV : : ' " " " " ' - " ' •••

As previ'ous'l meritlohed, "groxind water sampling..and analysis wouldbe. per-formeid. for':;certa:In.- existijig monitoring "wells and new wellswould be .inst-alred."l"n" c"6Xfb"rm ce;witV""co4e. ,pf .Maryland AnnotatedRegulation. ..(CpiMARr/2g;,p 04_.;. . Samples; ^rprrv s'elect. residentialwells" would also, be analyzed. "Ground ;wa.ter:':elevatlon, .pH,temperature:...a"nd conductivity measurements.'.w^uld be recorded .foreach sampling "j3erl.6'a. -""""Gf"5und water-" sample/s';'rwould be analyzed forvolatile ...and semi~v'6latHe dr"g:aTil;c/\c6fipiDU"h"ds",: pesticides andmetals. , ----- :- '• "•". " - - - • * - - - - " > - - - =-----. . ••:.- -—. --..---, . - : - - - . -. .- - - -

Wellhe.a-d treatment or ""a replacement well "would' be provided at anyresidence.:;"wher.e-...Site"-relate.d' contamlnants"."were..determined to" bepresent in. domestic well..water -=at concentrations that exceed theground water "--cleanup levels presented in Tables 9 .and 10. Theobjective, of i;th.e wellhead^ treatment, woul. be/.to-.. reduce the' 'concentrations/ o';;f;/S'c €levels.. -The "type of -Wellhead-treatment "system "to _be used woulddepend on tlie_contamlnaTTEs fo.und'/.durlng monitoring". •" Zeolite."fllters--:br""l"o"rT-e ?eHange r:esin-S./.;wciuld ..r.emove./Inq'rganic,contaminants, ihc.ludInY""mang:an'e:se"V'"from tlie' nousehold .water

32

A R 3 I 1679

supplies. Carbon adsorption units have been shown to be .-._ /_.effective in removing VOCs. Air stripping units are alsocommercially available for VOC removal far" residential.applications. Alternatively, a replacement well would berequired to provide, a sufficient quantity of water that meets theground water cleanup levels. EPA, in consultation with MDE,would determine the choice of .'alternate... water supply and theexact components and configuration of/the wellhead treatmentsystem during the remedial design.

Residual wastes from.the wellhead treatment.units in the form ofspent carbon or filtration media would .be evaluated in accordancewith the hazardous waste Identification requirements of'40 C..F.R.§ 261.24, COMARs 10.51.02.10, .11.and..12 (1985), and" COMARs26.13.02.11," .12 and .13.6 On-site handling of any residual '.'wastes found to exhibit a characteristic of a hazardous wastewould comply with standards applicable to generators of hazardouswaste (COMARs 10.51.03.01, .03., .04, .05 and .06 [1985], andCOMARs 26.13.03.01, .03, .04, .05, .06 and .08) and transporters.of hazardous waste (COMARs 10.51.04.01, .02, .03 and .04 [1985],and COMARs 26.13.04.01, .02, .03 and .04.}.. The federal-landdisposal restrictions contained in 40 C.F.R. Part 2£8 would alsoapply to any off-site" disposal of residual .wastes found toexhibit a characteristic of a hazardous, waste. As previouslynoted, the costs for provision of an alternate water supply anddisposal of treatment residuals were not included in the cost "figures listed above for this "alternative.. ... :.

Surface water and sediment samples would be collected..fromupstream and downstream locations in the unnamed creek. These ...samples would be.analyzed for volatile and semivolatlle -organic-_-compounds, pesticides and metals. In addition, surface waterparameters such as temperature, dissolved oxygen, pH,conductivity and flow rate would be measured at. each /.samplingstation. Surface water samples from each station would ..also be .analyzed for total suspended solids, alkalinity and hardness.Similarly, the temperature, oxidation-reduction potential (Eh),pH, conductivity and color ..(as determined by comparison with theMunsell Soil .Color Charts) of sediments at each sample locationwould be measured. Sediment samples from each sampling locationwould also be analyzed for total. organic-, carbon, grain size,

6 The 1985 Maryland regulations cited in this-ROD are thefederally-authorized Resource Conservation and Recovery Act -(RCRA)regulations. These regulations have been subsequently amended bythe State of Maryland and recodified in Title/26, Subtitle 13, ofthe Code of Maryland Regulations (COMARs) . Where the". 1985regulations appear in this ROD, the-Title 26 COMARs are citedafter them. A copy of the 1985 Maryland regulations is containedin the Administrative Record. • . • . . •- ••"•"

33

A R 3 1 1680

percent mo.i"sture~:"and "percent .s"6Ilb!s"."" '/Biological monitoring ofaquatic- macra.±nve:rtebrates_.;would -be conducted, .twice.a year .for !..the first year; of rri;6rilt6rihq_/a'hd Once "!a year thereafter.

9. -^ Sr V

Several" criteria .:w-6uld 'be ' used" to! evalua'te/the -stream monitoringdata" and assess""the need-for..:additional remedial" action to" . . 'address any adverse Sit~e-reU>"te<i""l_mp/a"£ Thecriteria,:±.ox,/sur-fa"ce-.water.Xn'clude/upgradient .stream..conditions,State "water-Liquallty" standards and federal .ambient water quality'criteria.- For sediments,;" Apparent Effects Thresholds (AETs) andNational jOceanic aW "Atmospheric Administration.! (NOAA). BiologicalEf f ects'I"R"ah"g;e""-";ji:o""w;j":(EE! lj] "".yal"ues""woul"d." Be/considered ininterpretation"/ oflthe'lEonitorln-^data/ Methods, -described inEPA's guidance dQcume:n;t,"/;£«3pI3 "B'ioassessxie'nt Protocol -far Use _inStreams' and Ri.ve.rs: B'enthic M.acro.invefj:teb.rates and Fish1.(EPA/444/4-89-QG1",' May 1989) ," would' also: be !,used to detect theexistence,and.characterize the severity of potential Site—impactson the.unnamed creek that crosses .the Site.

In order to /evaluate"potential off-site'migration of landfill,gas, a. network, of nested soil./aas .monitorir£g "probes would beinstalled-around the laridfi.il near/'the' Slt£bp.undary. Gas :s.ampl_e ; ^ ,-b_e.-"coO±l "Led_p"n •a"""qu"arteXly/Basis_ and analyzed .for".VOCs .and"" methane. :EPA," In "consultation^ with MDE, would evaluate.the..monitoring results inbrder """to •determine., the need . for .furtheractions, to ,protect the. health ' and safety "of/surrounding "residents(e.g., installation "of a"""perim"eter._passive-gas 'collectionsystem) .. . "" " . ..._.- ..... J_ . ......._._-... *._. --

The .costs ".llsted:"a"Hove~r"a"re based on 'quarterly monitoring of.ground-watery including the., wat.er _in...domestic wells, and the ..unnamedLcreek. However, EPA, in consultation with MDE, could 'determine "that the sampling /regueriCy' should be, decreased at..theen'd of .a:,.one :br:x:tw;d 'e'a;C!l>¥ri 41 annual .samplingif measured concentrations remalne;d...bel6w'/t£e. ground watercleanup levels.-or "Stream .'action' levels'" and no upward trends inthe ."concentrations. "Of : :dntam"Iria'nts/.-of"" cancefn. were; observedbetween sampling" events"-:".-.'":~ "-'"••-." ", . :".., .: "-::f/:j:;. - - "/:;

Alternative 3: Excavation of Drain Field Soils, Capping,Monitoring, Institutional Controls, PerimeterFencing, Treatment at Contaminated ResidentialWells

Capital.-Costs:- ._.. - ~:: -.$17,7J2,'QQQ'""* ——---•" ' ' J •Annual .&&& "Costs: " " " " '

This .g;uldari_ce". "document"" w"a/s"i/deve"l"ope"d/.|!sr, streams in theAppalachian ""Plateau -fefi;-oH"": "v" •!ti:"1"nec'es"$a y;"''IE''pu would adjust themethods, prescribed therein "f 6r .local" conditions .

34

A R 3 1 168

Present Worth: $15,856,000. ._ , ".. ... :' •-. _. .Years to Implement: 5

All of the elements described in Alternative 2, with the__exception of the revegetation of the existing landfill', cover,would also be included In Alternative 3,.. Alternative 3 would notprovide any action to remediate ground water but would provide ...physical containment of the source, materials. ...

Capping of the source areas under this alternative would .minimizethe amount of precipitation that may infiltrate" into wastematerials and soils and mobilize constituents therein. Cappingwould also create a physical barrier that would prevent contact --of ecological receptors with contaminated surface' soils and seepsediments .

Prior to installation of the cap, approximately 400 cubic yardsof mercury-contaminated surface soils 'would be =testecL andexcavated from the abandoned septic system drain field. If thesoils did not exhibit the characteristic, of . toxicity as defined."in 40 C.F.R. § 261.24, they would be consolidated near the centerof the landfill. If the soils did exhibit . the toxicitycharacteristic, they would be disposed of .at an of f-~slte~ "ResourceConservation and Recovery Act (RCRA) hazardous waste (Subtitle C)disposal facility. On-site handling of any such hazardous wasteswould be In compliance with standards applicable to::gene'rators ofhazardous waste {COMARs 10.51.03.01, .03, .04, .05 and .06[1985], and COMARs 26.13. 03 ...01, .03, .04, .05, .06 and .08) andtransporters of hazardous waste (COMARs 10.51. 04 . 01," \ 02, .03 and.04 [1985], and COMARs 26.13.04.01, .02, .03 and .04). The ..federal land disposal restrictions contained in 40 C.'F.R. Part268 would also apply to the of f-site -disposal of any soils foundto exhibit the toxicity characteristic. - .. - • .. _ .... .. -.

The currently-operating septic system drain field, locatedof the Transfer Station, would be relocated in order -to eliminateany flow of water from the septic system into areas where PVCsludge and other .wastes were placed. . . . . . _._ _ _ _

A cap would be placed over the landfill and identified cells ofPVC sludge. It would consist, from the bottom up, "of a preparedsubbase, gas collection zone, low permeability layer, drainage •layer, cover material, topsail and a vegetative- layer. The totalarea to be capped would be approximately 31 acres, --The/capspecifications would be consistent with the single-barrier caprequirements presented in the EPA Municipal Landfill Guidance .andwould meet or exceed the landfill closure cap requirementsspecified In COMARs 26.04 . 07 .21 . B and E.

Predesign studies would be conducted in order. -to . delineate theboundaries of the fill material, including the boundaries of. .PVC.

35

AR3!1682

sludge -disposal .Cells-t'and B/C.'""r The"" actual' areal'-extent of ' the_cap' will "be j based" -on the..data .gathered ..during the.' RI and .predeslgn studies and will :t>e "determined -"by' EPA, in consultationwith MpE, during the "design" phase. ~f--r ..:

Both... passive': Sird" ac'tive'.gas" collection .systems' were/evaluated ascomponents -of'/the .cap ;ln" the FS. The primary function of apasslve ..sys'teffi"" " f""g ^ .the rej-e.as.e ;o.f...... .landfill "gals:e~ o"*the7"arjnosphere -in .order to minimize potentiallydangerous, .conditions..due" .to gas buildup; beneath the cap. Anactive ;gas .collection .sys'tem .'would prevent the buildup of gases -beneath, the .cap an'd .control .emissions"" of .landfill gases to -theatmosphere—--"-Additional "studies would be performed prior to the". -.design "-Of".'the cap "in order to determine landfill gas constituentsand the rate..:.of_. emissions".' Ba'sed on" "the"re'sults .of these ,studies, EPA, In consultatlbn'"'w"lth "MDE, "would, determine duringthe-.design" phase whetherTan active gas collection system isrequired In order ,.to ..Comply with t"he.._substantive .portions 'ofState., requirements" governing " air gU4 ity'''rCD.M.ARs 26.. 11. 06". 02,. 03, . 0;6r*Vcrr~anld=y.'09r t*^ 11.19.02 G)or in order .to. protect., human health, welfare, or. the environment.

The -cost_ fig'ures/V-a'bove.-reflectTestimates/for installation of apassive gas collection .system. The capital. ..cost" of/' an .active gascollection aha" "treatment system . 'wqgldL .be a"pproximately $1,6"million, about $"8.QU","dO"0""inore vtnan "th"e"cost//o"f the passive system.The annual O&M costs". associated, with ..the active collectionsystem" "would be approximately $_850_,000, assuming, t ie gas would bethermally- treated ..in .flarestac.ks." "" "" ...../.... "...." ... • .

The low" perme ability ""layer o /t'h'e/da'rj "wo"ulci""" consist of -two ..feetof "clay with a permeability less "than or equal to .1 X 1CT7centimeters. pe~r .. secono^ (cm/sec)" or .al. synthetic., liner .. that" isequally prote.cti.ve","" !" determined by EPA, in consultation withMDE, during "the: remedial design, " ..?.or /cost-es.timating purposes,the low. permeability" la"yer was .'assumed "to_ consist of 'two feet ofclay with a perme"abllity" of 1 X' 10~7 cm/sec." . ' '

A'drairiag^e layer^- would "be. -c;ori:s:tru"ct_eH_i medi.ately above the lowpermeability "i a ]/e"r.r 1 6 "' collect "water7 that ."percolates through ^hesoil-cover.- -The "drainage layer .would "consist of naturalmaterials, (js.cf. ~ sand .with _a__p_erme.abilit;y equal,...t-0 -or greater . .than 10 ." cm/sec) /or. a":syhthetic., . high permeabiiity geone't"sandwiched" between layers of filter ."fabric ..which' would inhibitthe .mlgr t:ionv-0f ,-jEine..s:dil . particle's, /intQ_ 'the flow area of thegeo.net..-. .This ..highly permeable layer would; divert percolatedwater away from, the, -clay layer to /a network. .of slotted or.perf o'rated. -"collection .pipes-;1 . :,The pipes would, in' turn, conveythe percolated water to. .drainage ditches along- the edges' of thecap. •••'-.. ~ . "-"'•• ' - - • - • " :- '-ia--1'-- -

36

A R 3 1 1683

An 18-inch-thick layer of cover material would be installed abovethe drainage layer. Six inches of topsoil would be placed on thesurface of the cover material. A vegetative layer would" be... . ...established on the completed cap.

Alternative 4: Excavation of Drain Field Soils, Capping, GroundWater Extraction and Treatment, Monitoring,Institutional Controls, Perimeter Fencing,Wellhead Treatment at Contaminated ResidentialWells

Capital Costs-: $20,997,000 . ' ."" . . :_Annual O&M Costs: $1,609,000 ' .".'"_ "Present Worth: $23,826,000 . ... . . . . .Years to Implement: 6 •

The monitoring program, institutional controls and perimeterfencing described for Alternative .2 and the soil excavation andcap described for Alternative 3 would also"be. included inAlternative 4. In addition./ Alternative 4 would provideremediation of contaminated ground water. - -:

An estimated 40 extraction wells would-be installed in the areaof Cell B/C and around the perimeter of the landfill"" in order toeffectively capture the plume and to withdraw ground.water untilthe concentrations of contaminants remaining in the__ ground waterno longer exceed the ground water cleanup levels. The extracted.ground water would be treated on-site to reduce contaminantlevels to concentrations that are protective of surf ace ""water .,_.quality, and would be discharged to the stream at the southernend of the landfill property.

The approximate locations of the .ground water -extraction wells... -are shown in Figure 4. The well, "configuration shown in Figure 4is preliminary and may be further refined during remedial-design.The estimated peak flow rate of the ground water recovery systemwould be 200 gallons per minute. The actual flow rate of ..:extracted ground water would be expected to decreasesignificantly with time.

It is expected that the concentration of vinyl chloride in groundwater would decrease to the 1 ! g/L cleanup level within the areaof attainment after 12 years of operation of the ground waterrecovery system. However, ground water extraction and treatmentwould continue until the ground water cleanup levels' were -achieved for all-.contaminants identified in Tables 9." and 10,including semivolatile organic compounds and metals. As noted inTables 9 and 10, EPA will, take background levels -O.£: .arsenic andmanganese into account in determining whether the ground waterremedial objectives have bee,n achieved. EPA, in consultation

37

H R 3 1 I 6 8 U

with MDE, 'will determine .background levels. o,f arsenic andmangane"s'e""at"~Th.e -Site, ."during "the" remedial. design', based, on theresults -o:f--a-:'-pre:oresign""s'"t:udy. /" "

Extracted, ground water -yduld be treated" on-site in a three-steppr.°ces /Z::Tj -jq,rs ^ anclf locculatlon/coagxilatidh": to" 're^iribvV/rftaiiganes/e^ and other inorganic"-contaminant.s_.___A;-treatability 'study ' would" be/performed before 'final design "of /"the treatment ;_sys'tem ;in\qrdj;r. ._to /optimise.conditions "fbf removal ,;of irve als ..' /JtL the" second', step, thefiltered ef fluent, from ±he ."precipitation 'unit would be piped to.an air stripper-'te-blumh/"fo'r"'Fe"mbval/..o-r:voCs//. -finally, '"the groundwater-. discharged^ from- the; air _s tripper, wb.uld be passed throughgranular .activated- carbon to, remove', semi-volatile organiccompounds and "any remaining contartrinahts". "The. treated- groundwater., would then be "dis charged to .the stream that crosses thesouthern end of ~the_Site.. Discharge, limitations would bedeveloped based, on. "State_ wa.t_er ...guallty standards (COMARs26.08..027tJ3'-T9'~3:r3T/ federaT ambient, water . 'quality criteria _ • •established pursuant " "to Section 304 of. the Clean Water Act, 33U.S.C. §. 1311'," -which apply to the. protection Of "aquatic, life,MCLs and -non-zera -MCLGs". " T"h"eT discharge would, also comply with" •substantive. .portions 'of State -a:rid" 'Clean' Water Act .requirements ".pertaining tor-.p-olnt. source discharges7' "tp. surface .water, including.discharge limitations .'{.Section 402. of- the." "Clean Water Act, 33U.S.C. -§--1342; C Rs' 6. 08 . IJBTCil'" -/OTT^^standards for bestmanagement pra tTcesr' (=4.t5 :C-."F/R/' p"art""±25/ "Subpart "K) ,' and testpro-cedures- ..(40. C-.F.R.' Part ,13"6}:. """:_;":.. :/-"/:™/" "-.'.''.' . '

Potential. impacts - to. human health .from the air stripper whichwould be used, to- t.rea;ii.:':c^ were evaluatedin the FS. --The maximum" predicted .air emission rate of vinylchloride ':'fr6M"lThe""air/-str"ipper".w"as "estimated to 'be 4 . 5 ".X 10~3pounds perrhour (5.7 l'0;"f. gra'm'S. per-second [g/sec] J ." However,the -emission ratevir^e^cpedted^tp /decline/ as ;:ground water. .. . . .remediation progresses. "-:: Based pn: """currefit 'projections- regardingthe.. prQgressiv.e r iductio.ri' in" th"e' "vlnyT chloride.' concentration "over time, an "average"" 'anOTal :'v3:nyl chjoride^emission rate of 6 2 'pounds per year .T8V91 X-10 5 g/sec:} was _p.redibted. -Using themethods :prescrabed ±ri cr &i h - Met Eq . .far _ the" Development ofAir_.:_ Toxics ..Emission - ac"t.d; _;.(BP;A-450/.4-.91-Q2!l/ September 1991)and preliminary inf O'rma tion'- regarding. th'i./l.QcatiQn of theproposed a"lr" sf ro perT'arid "assrnning-_a 'vinyJ'j::hlQr;ide air emissionrate ;.o.C".8_. a_X 1.0 . -g/sac,' a""Yriaximum 'Hourly "vinyl ' chloride, .'concentration \ox:..7 : g "7Vas_ projected "in"rt}ie" ambient air .atthe -location, of -£h""e. neareS'f" residential" "fece^tor .

The estimate.d excess:life time a ncei: .risk 'for "&. child exposed tothis -level of vinyl chloride", in "'ambient, air 'over : a 12-year period(the estimated,'time: frame:ibrV"•attainment "of"""fne" ground water

38.

flR3M685

cleanup levels for vinyl chloride) is 5..8.X 10"-., - Thisincremental cancer risk estimate does .not exceed the 1 X 10~_-lower limit of EPA's target.risk range. However, the estimate ....does not include incremental risk associated with, exposure toemissions of VOCs other than vinyl chloride.. -In addition, theassumptions used to calculate this risk.may not remain valid; if.conditions at the Site or design considerations change prior- to .remedy design and implementation. Therefore, air emission anddispersion modeling and a long-term exposure evaluation.would beperformed during the predesign phase in order'to better:definepotential risk to human health resulting, from "exposure to VOCemissions from the air stripper, . .._...• ....:_._ ... ... ...

Emission controls would be'provided if .EPA, in consultation withMDE, determined that emissions from" the air stripper ;stack couldresult in an excess lifetime cancer, risk greater than. l.-O X 10"for exposed individuals. Air emission controls would also beprovided if necessary to comply with State regulations pertainingto toxic air pollutants (COMAR 26.11.1$), federal-air" emission •standards for process vents (40 C.F.R. Part 264, Subpart AA), orState requirements pertaining to emission of VOCs {.COMAR26.11.06.06). The EPA guidance document. Control o'f'.Air-Emissions from Superfund Air Strippers at Superfund'GroundwaterSites {OSWER Directive 9355.0-28, June 15, 1989}, would'also beconsidered in determining the need for air emission .'controls. .The costs for evaluating potential human health impacts -fromexposure to air emissions from the stripper column and for • . . -;providing emission controls were not Included in the cost figureslisted above for this alternative.. / . . ....

The treatment of ground water under Alternative 4 .may result in.the generation of residual wastes. .Any" residual wastes would beevaluated in accordance with the hazardous waste .Identification .requirements of- 40 C.F.R. § 261.24, COMARs 10.51.OZ-10, .11 and.12 (1985), and COMARs 26.13.Q2.il, .12 and .13. On-site. .. ..handling of any residual wastes found to exhibit a -characteristicof a hazardous waste would comply with standards- applicable togenerators of hazardous waste (COMARs 10.51.031.01, .03, ".04, .05and .06 [1985], and COMARs 26.13.03.01, .03, ".04, .05, .06 and.08) and transporters of hazardous waste (COMARs 10.51.04.01,,02, .03 and .04 [1985], and .COMARs 26/13.Q4.01, .02, .03 and.04). The federal land disposal restrictions, contained in 40C.F.R. Part 268 would also apply to any off-site disposal of . __residual wastes found to exhibit a characteristic .a£.__a hazardouswaste.

Some uncertainty exists as to whether .ground water ...collectionwill significantly reduce the concentrations .of contaminants inground water. Increased flow velocities caused by pumping maynot allow enough time for contaminants in ground water and .soil.in the saturated zone to reach equilibrium. The desorption of '.

39.

A R 3 I 1686

contaminants, from "the aquifer, .soils .may "be _the rate-limiting stepin contaminant removal - from the agulf er . . ;;,i"n: Order to overcomethis-- potential problem", /rSalsed"'pum"p 1i ""rfLay have "to be employed _tjopromote equilibration between contaminants in soils .and groundwater ..s-cr-tha.t contaminants :may^ be more-; .effectively' removed from""the aquifer,. :Affil'fe£/''tSs''ts ; ogld. '.need/ tcTjpe " pe/rformed duringremedial -deslgnr"and; possibly "during 'the remedial action, inorder to. -Optimize • Recovery of "-contaminants' 'with 'a pulsed pumpingsystem. ../The pumping ira'tes/:and".. other : operational considerations /associated. .with "the" "ground water .collection system would bedetermined by EPA, in consultation, with MDE, during the remedialdesign. :phas.e.. ..r:.- — . --"-."" --_•-———;,- •-•-—-- ;.-—•"_•- / , - '.... .. ;.

Alternative 5: Excavation of Drain Field Soils, Excavation andOn-site Low Temperature Thermal Treatment of PVCSludge, Capping, Ground Water Extraction andTreatment, Monitoring, Institutional Controls,Perimeter Fencing, Wellhead Treatment atContaminated Residential Wells

Capital "::Costs":~""/-l--:"$35:, 372 ,-QOO "/ /:"/". " ""Annual -O&M Costs: ---/$!, 6T09, OtTOf'!/ /: " ""/""I.... ' 'Present- IWOrth":"" ".. "$3"07905V 00"d" :. '."'/." *..''"l""""""~ " .'

• ' Years" to. "Implemeht: " ":7-"::: "'"-- ":" ' "~:.:.l .".™:"1" 'T - -'-' ' "- -

All elements- 'Vf '-'Alternative' 14. would al p'/be/, included inAlternative. .5, - Alternative. S..woul_d_ pr_ovlde institutional .controls, perlm'e.te'r. .-fencing, ' frodnd 'WateT extfaction andtreatment; monfi'toring," soil. .excavation, and'.a "cap over thelandfill and" PVC sludge^di^gqsal; cells,. In "addition,approximately _3.&,'00tl '/cubic "yards of P. VC." sludge -.and contaminatedsoils -would be,.e caTOlLe6v±rom Cell B"/C"-and .Cell A (if found) andtreated on-si.te" -using low" temperature- thermal desorption. '" •

The. sludge' treatmej -. jDro ess;.;fOi ^ federal standardsfor .-air " eWlrs lbns"7" f r6m:"prbces"s' ""vents ft 40 C/F/Jl. Part' 264, SubpartAA")- and the .requirements, .for', thermal .treatment ".of "hazardous waste(40. C.F.R. Part 26T,~. Subpart . X^.ahd 40 .C.F.R. Part 2^5, SubpartP) . Samples of the. treated/material.. wpuld7beL analyzed to ensureattainment of. .cleanup levels. T?h"e 'treated sludge would-bebackfilled. in't/o-/th"e"/ .excavated/. cell area". if , the material" did notexhibit .any of- .the characteristicsX.o.f haza-rdou.s waste as definedin 40 C.F.R. § 2-6.1- ," COMARs l.D_. 51. 02". 10, .11 and .12 "(1985),and COMARs" 26, 15.."02;ilV"-VI2. and" .13. //"""""-//•/ . " " . - •

The^tota.1 time required for" treatment of the waste .is estimated.at o.ne-and-a-half--to. .two. years ;/" Cons'tructidn "of the .31 -acre cap "and installation o"£ certain .rfebo.Vety 'wells would no_t begin untilthe. sludge tr Eiment; had" "been cDmpleted. " ./ "

A prelimihar.y''t"re"a"t;abillTy' study was perforiaed "during the FS In

40

A R 3 ! 1 6 8 7

order to investigate the feasibility of treating'the PVC sludgewastes using low temperature thermal, desorption. Tests were runover, a range of temperatures extending from.125 to' 7'CTQ degreesCelsius. The test results indicated the., formation andpersistence of chlorinated "daughter" products and other thermaldegradation products at certain temperatures. Further pilot-testing would be required prior to implementation of thisalternative in order to optimize the design of the thermaltreatment unit. - -

The cost figures listed above do not include pilot-testing or thetreatment of Cell A wastes. . It was not possible to determine thevolume of material in .Cell A because no PVC sludge was foundduring the RI in the area thought to be occupied by Cell A.

Alternative 6: Excavation of Drain Field Soils, Excavation andOff-site Disposal of PVC Sludge, Capping, GroundWater Extraction and Treatment, Monitoring,Institutional Controls, Perimeter Fencing,Wellhead Treatment at Contaminated ResidentialWells

Capital Costs: $41,253,000 . . . ,..Annual 0&M Costs: $1,609,000Present Worth: $37,135,000 ."Years to Implement: 7

All elements of Alternative 4. would also-be. Included inAlternative 6.' Alternative 6 would provide institutionalcontrols, perimeter fencing, ground water extraction andtreatment, monitoring, and a cap over -the landfill-and PVC sludgedisposal cells. Xn addition, approximately 36,000..cubic yards ofPVC sludge and contaminated soils would be excavated"from CellB/C and Cell A, if it is found, and transported to an off-sitelandfill for disposal. . '•_ .

An industrial waste landfill was identified, in York,Pennsylvania, approximately 80 miles from Cecil County. The costestimate for this alternative is based on disposal of the PVCsludge and contaminated soils at that landfill, ." ..:.;.

Testing conducted during the RI/FS indicates that the PVC sluolgein Cell B/C does .not exhibit the characteristics of'., hazardouswaste as defined in 40 C.F.R. Part. 261," Subpart. C, and that thismaterial may be accepted by a RCRA industrial waste- (Subtitle D)landfill. However, the receiving facility may require additionaltesting to verify the ability of the 'disposal facility to acceptthe sludge and contaminated soils.. In the event that futureanalyses of excavated PVC sludge and contaminated soils indicatesthat any portion of the material exhibits, any characteristic ofhazardous waste as defined in 40 C.F.R, § 261.24, COMARs

41

flR31 1688

10". 51". 02:i"0'r \'ll~no::Ti 'ftB5yr ana"cl5MBs-26.13. 2l, . 12' and ".13, that, portion of, the material would have to be 'treated on-.- -site.-,or"."dispos.e"4_Ojf://frf;/| (SubtitleC} facility/ /On-site Ihan-dllng o f .any""su.ch. hazardous wastes wouldbe. in compllan"ce..:with standards _applicable 'to, generators of. .hazardous wa'ste (COMfigs-1 l'O/5'l"/OT. O'l, L .TO, /:/C5""4," V05 'and . 06.. .[1985] ,"a"n"dl""CDMAKs'i:'2Trf31.-a3:'OT, "0.3, '. 0 4 3'5,' '. 06 and .08) andtransporters "Of hazardous waste";.: .(CQMARs IQ-^ • 04 . 01, .02"," .0.3 and.0_4 [1985], and" COMARs '26.13 0*4.01, ..$2, "","53'/and .04). Thefederal" land" disposal restrlct.Ip.ns j qn tainec],. .Iri" 40 -C.F.R. _ Part.268 would"! also, .apply to. ".fcne o;f"f-s"lte disposal "of any soils foundto .exhibit the. toxicity' characteristic." ~" '-'- -"

Costs f d=r;/:dn' Si''tel/rl£'e/ati:ment" o±' Ehe. PVC sludge, or disposal of.. thePVC sludge at "a""R"C.RA hazardous ;waste~". ("Subtitle C} facility, werenot Included in" the cost, figures; listed aboye: for this ..alternative.1 In" addition, since"", sludge disposal Cell A could notbe found during the .RI, costs; J or e x yatlpii'.Xhd .Of f-site - •disposal of._/Cell"/A' wastes were..not included in the cost figures.

9.0 SUMMARY OF COMPARATIVE ANALYSIS OF AI/TERHATIVES

The six .reme'dial. action alternatives-described above werecompared against' the n.1 ne evaluation' criteraJ"Set .flprt.h. in theNCP, 40 C-.-F.R. § "3UOV430Te')T9iV'' Thesejnine"evaluation' criteriacan be categorized, into' three groups:"_./' threshold criteria,primary balancing .criteria", and modifying i.criteria. The criteriaassociated with each, category are.' as follows": •- •

THRESHOLD-CRITERIA " " . . ""./".. "/„:/, . . . . . . . .

Overall,-pro-tectlon Of" human .health.,,and the environmentCompliance with, applicable..or,:relevant' and. appropriate

"" " " " "

PRIMARY. BALANCJN.G; CRITERIA'.Long-term. e.f:fectivenes'"s - " _ - : . '.-."" ._"."] "t.. - .- .Reduction of. ..toxicity, mobility, 6r~v"olume through.treatment . : . _ . . '-—-• --:L_- _..:•_. .--.-.i_-_,.._.. .....Short-term eff e:cltlvene"sls_ '""' """~/1'- _ ';-"""/:/; """'-._' _ ,_ .•Implementabirity" """'"'" "" "" : _._._. __,.... ......

" "" " = "

Comrnu'nity. "accepJt'ance; '"/ !;Support-_.agen"cy-. acceptance

These":"e.v"Eluatio.n . c l terla '..r;.elat;er'"dlrec" tly "to u requirements inSect.ibln/121-:orT:ElcSJt,:"-f ""U.S.C. '§ '.36217 = which determine the

42

A R 3 I 1689

overall feasibility and acceptability of the remedy. Threshold. ...criteria must be satisfied in order for a.remedy to. be eligible"for selection. Primary balancing criteria are: rused to weigh,major trade-offs" between remedies. Support agency _and communityacceptance are modifying criteria.which are taken into accountafter public comment is received on the Proposed Plan.

The following discussion evaluates the six remedial.alternativesdeveloped for the" Woodlawn Landfill Site against the ninecriteria set forth in the NCP.

9.1 Overall Protection of Human Health and the Environment

A primary requirement of CERCLA is"that the selected remedial-action be protective of human health and the environment. Aremedy is protective if it reduces current"and potential risksassociated with each exposure pathway at a Site to. acceptablelevels.

Alternative 1 (No Action) contains no provisions fo"r"pre~vent"ingexposure to contamination, and is not protective..of human healthand the environment. Although Alternative.2 includes measuresfor preventing human exposure to unacceptable levels ."of Site.contaminants, Alternative 2 'does not include capping, and wouldnot prevent exposure of ecological.receptors to mercury-contaminated soils and contaminated seep sediments.. .Therefore,Alternative 2 would .not be considered protective of ,the.environment- Since Alternatives 1. and' 2 do not satisfy thethreshold criterion of protectiveness, they will not_be .considered further in this analysis. ...._.__..._ ...... _ _ _ _ _ _ _ ... • ..

Alternatives 3 through 6 would provide adequate protection ofhuman health by preventing exposure to contaminated ground waterthrough provision of an alternate water supply or"polnt-of-entry;treatment and institution of ground water use restrictions.Alternatives 3 through 6 would also Inhibit migration ofcontaminants into ground water through capping, which would. . ...reduce the amount of precipitation that may infiltrate andmobilize contaminants In the wastes, and prevent exposure ofecological receptors to mercury-contaminated soils andcontaminated seep sediments, - . . . . . . _ . . :

Alternatives 3 through 6 call for monitoring of the stream thatcrosses the Site, which would identify conditions that warrantadditional actions to protect aquatic life and comply with ARARsAlternatives 4 through 6 offer.advantages over Alternative 3,however, because they provide for active/treatment ...of groundwater, which would minimize migration of" contaminants anddiminish loading of contaminants to -the stream.

Following the completion of the .remedial action, the. residual

43

AR3! S690

risks far-each of" Alternatives""?,". B^and""6v""would. be the same"because" each 'of-.!these alternatives .WO'.Uld achieve the same groundwater, cleanup levels'/and "ffe vent exposure-"'to contaminated soils-and sediments"." "":"'"~""". ":"::.:.:"/:.'..:'... .1."_£•:• " - " : ": """" "• •

9.2 Compliance-with ARARs

Thls_\crltejilon: .address es ' 'whet her a, remedy, .will, meet, .all of , theapplicable, or:.7r l4Var ..in"4'/app"t6.5r'ia"te"" requirements (ARARs) offederal, and s_ a_te:_en vir,oh:mejLital laws and7br/ will provide groundsfor. Invoking "a- walVer't" """-"""" --——— :;; . . ;/ / "'"."-".'•

The Maximum C"on"t nanjt:~_;LeV Maximum'Contaminant "KveT* 'Goals' " ""WCtSsT' r :pffiiic"drinking water.supplies -established/under _the Safe Drinking Water. Act, 42 U.S.C.§"§ 3QOf /etl se ^ Wre grgmeiff ;;tq be^ xel.e-vant" and ' appropriate -standards, for. . ojifi / te Superfund program.The ' cont:erlt;±at "6hB7""6r''1s ef"S!I"."cdnt:" Lin ' water..underlying the landfill/property exceed .MCLs / Since Alternativea., would do nothing to .-r.educ.e the concentration... ..of. thesecontaminants , it_ would not. "result" In "compliance " with this . ARAR .Therefore, "rlt will-., nbtl '.be '"considered./ further "."in this analysis .

Under. Alternatives. 4.7-5 /and '"6, 'ground, water : would be extracted-and treated. These - alternatives. ..would ultimately comply withMCLs L and non-zero MCLGs for . inorganic, and ofgahic";chemlcals(40 C.F.R. §§;.l41.1i^l2-A114l.5D-v-5.i, "and "1 41.. 61-. 62} / HealthEffect's. Assessments and "U.S . 'EPX" Health/Advisories wereconsidered in establishing ground water. /cleanup levels for theSite, and would beLcon>i<ie_r._e.d...i,n___evaluating the protect! veness ofAlternatives". 4 . through" 6.".' . . . . " . " . ','.....

The .-.treatment" : of "groffna water: inr- A'l'telnatiyes 4 through 6 would . -result in ..V.OCIe"itLis"sTon:s7f;rom' an air Jtfi^per. %6 ambient air.. Airemission conTrolsT y /be ecelsj r ' Ift^Ordgr .."tb.; meet State andfederal reo;uireme ts.""-£ "Strippers. . Theserequiremerlts^include/State regulations, pertaining to toxic airpollutants, Including the ..regulations;, that: .establish standardsfor .hazardous .airypollutants. (COMAR" 26,11.15) , federal airemission standards/for process." vents "{40 "C.-F.R. Part 264,Subpart.. AA)_, and State' -Jreqtil;reme'nt..s pertaining to emission's ofVOCs -(CCMAR -Tr _5?0 5Ti;TiO|A guidance^ fto.cumerit entitledControl., &f... 'Air. Emissions. ~££6m - Super fun ' t. ''Strippers at5upe Jf d.;. r ;D2 at:er_Site5 (OS.WER Direct! vel 9355 . 0-28, June 15,19.83.), would be -considered: in asse'ssln the/need 'for. controllingair -emis:sioJn"S"~'f.rOm:thelaXr' stripper. " " "' ~~."."- ':

The treatment of 7g uhy"wate;£/m/ te iia"tiv "l "through '6 may "also: ".result" in "the .g'eneratioln" of /residual wastes. Any residualwastes would be esraluated_in . a'c cpMancJi -with "the hazardous wasteIdentification requirement's "br"/.40":.C. F.R. § 261.24, COMARs

44

AR3! 169

10.51.02,10, .11 and .12 (1985), and COMARs 26.13.02.11, .12 and.13. On-site handling of any residual wastes found .to exhibit acharacteristic of ..a hazardous waste would comply with standardsapplicable to generators-of hazardous waste (COMARs ,10 .51. 03.. 01,..03, .04, .05 and .06 [1985], and COMARs 26/.1T.03. Ql, .03, .'04,.05, .06 and- .08) and transporters of hazardous waste (COMARs10.51.04.01, .02, .03- and .04 [1985], and COMARs 26". 13.04 . 01,.02, .03 and .04). The federal land disposal restrictions -contained in 40 C.F.R. Part 268 would also apply .to., any. off-sitedisposal of residual wastes found to exhibit a characteristic ofa hazardous waste.

Alternatives 4, 5 and 6 each entail on-site discharge of treatedground water to the stream that crosses the southern end of__theSite. Although the stream is not currently used as. a publicwater supply, its potential for use as .a public water, supply is.protected under State regulations. State environmental'regulations also require the protection of aquatic life in thestream. Therefore, the discharge of "treated ground w'ater in eachof these alternatives would result in In-stream compliance withthe MCLs and non-zero MCLGs listed above, State water qualitystandards (COMARs 26.08.02.03-.03-3), and federal ambient waterquality criteria established pursuant to Section 304.of the CleanWater Act, 33 U.S.C. § 1314, which apply to the protection ofaquatic life. . .. _ .

In accordance with CERCLA § 121 (e), no federal, state or localpermit is required for the portion of any remedial actionconducted entirely on-site. However, Alternatives 4, 5"and 6would comply with the substantive portions of "State"and CleanWater Act requirements pertaining to point source discharges to. .surface water {Section 402 of the Clean Water Act, 33 U.S.C.§ 1342), including discharge limitations (COMARs 26.OS.03.01 and.07), standards for best management practices (40 C-F.R. Part125, Subpart K) and test procedures (40 C.F.R. Part 136).

Alternatives 5 and 6 require the excavation and placement ofwaste material from the PVC sludge disposal cells .and wouldcomply with federal and State hazardous waste identificationrequirements (40 C.F.'R. § 261.24, COMARs 10.51.02.10, .11 and .12[1985], and COMARs 26.13.02.11, .12 and" ".13) . " Alternative 5provides for on-slte treatment of the wastes by low temperaturethermal desorption. Alternative 6 provides for off-site disposalof the wastes. -On-site handling of any Cell "B/C. of" Cell A wastesor treated residuals found to exhibit any characteristic of_ahazardous waste would comply with standards applicable togenerators of hazardous waste , (COMARs 10.51.03.01, "."03, .04, .05and .06 [1985], and COMARs 26.13.03.0.1, .03, .04, .05, .06 and.08} and transporters of hazardous waste (COMARs 10.51.04.01,.02, .03 and ,04 [1985], and COMARs 26.13.04.01, .02, .03 and.04). The federal land disposal restrictions contained in 40

45

flR3! !692

?•/"•*: Par-t^eiB^would'alsp^ppiy to/ any off-site, disposal of CellBAG of =££11 ..A wastes, or", treated _residuals "found to exhibit a

" " " ' 1 "_

waste

Any .oil-site sEoxi W hazardous. wastes' ..in..Alternatiyes 5 and 6would comply with COMW.,ia..Si: 05l,.09- ;il3MT and C6MAR 26 13 OS 09'wn.lch--- e9ula.t£-;:£c C.QMAR .10., 5.1 05, IG- (1985T and COMAR ' '26,13.05.10, which regulate, tanks, COMAR" I.p;.5l . 05 . 11' (1985) 'andCOMAR 26,13_,a5./LJ.,." wh"lj.cii ^ COMAR "1 0 . 51 ,0.5 .12 . ._( 13*5") " aW" CWAR 2 6 ."13 1 OBTlz; wnich regulate wastepiles, 'and COMAR 10.51 . 05 . Of/USSS) and "COMAR 26. 13-. 05 . 07, whichregulate "the closure and jo_ost~-closur_gL:,care-. 'Of the storage unitsThe -alternatives-would comply" with the. substantive, requirements

of 40. C.F.R. Part- 2.64V /Subpart F, f ori-ldetectlng," " characterizingand responding- to . Releases- firbm. s.olid/waste' '-management units.

On-sIteLErea±raent c i.c2r::..7c/:wlste"s in Alternative 5:"would 'comply .with federal" standards for :air/emi5siQns " from "process 'vents (40 C.F.fc. Part. : 2:64 ,;. Subpart AA) and the requirements, forthermal -treatment of hazardous : waste (40'C-F R P'art 26"4Subpart.. :, and 40 C.F.R. Part 2.S5, "^Subpart I)"/ '

;""" and 6 .each call for construction "of a landfillcap and. post-closure monitoring and maintenance, in compliancewith app/op'rl:ate/S.t:aJ;J/.i;anafilX-G;iQ.sure Regulations - (COMA.Rs26.04.07.21 A, B, D and E and QOMAR 26. 04 . 07/22 A, B and C)COMAR 26.04..;07.2r;r;es1taFi;i"shes;minlmum d si&h requirements "formunicipal, landfill, closure cap's;' which have, been found, throughmodeling, not to., be... adegua'te for";±.his Site. - Therefore, theIn§ie7barrr v'ca_&/ s'pecl icatld-ns .presented in the' EPA MunicipalUandfill Guidance - werel/talken. Intp consideration in developingalternatives_jfor:-"the FS .and_wou.l"d""be, .considered in evaluating thep-rotecti^enessTof '-.the /cap design. -£andf ill'..lgas emissions wouldbe controlled,- if .-determinedly EPA, in consultation with MDE, tobe, necessary in" orde-r-lo,co^l;y:;wlth/;the.,suhstantive portions ofn?: t /J$qulSe t ^ S ^ tt ali:ty- (ColARs 26.11.06.02, " '.03, =.06, .OS^and .09, COMAR 2 6 .11, 11 5. and " COMAR 26.11.19.02 G) .

Alternatives. 4 '-L -5 and T/wouldjlso comply with the substantiverequirements ...of. the.. :f ollowing f ederal and State, environmentallaws: State_.,.r-equirements "associated with ; we 11 construction andrnS ™ffn4SSJ:?§OMARS^ f %' * °"- B -^ -*™-V ' stormwater, management(COMAR 26 0| 02) and . ...noAS_e pOllutipn,cOn"trpX:(COMARs 26.02.03. 02 'A (2) and BJ2) and COMAR. 26; CTZ .p A.} ; federal .and State •fe. -igtl s-- ° / f--P?.otec.tip.n;/_ Order"119900 and. COMAR 0 ,05 . 0'4) •; ancT federal regulations', for the ' -protection ol /^^ange£ed^^peclesL fl6"U. S/C. '§ 1531 "•" 50 f V RTV _ ±, t r\ <~i \- -— i"1 — -j .—v"", • "•' *••"«.«•• s -sfc-js-M. -—*, - \--— •*. . i-< . -^ . & j- / j., *J \J \~r . C . r\ -

I ^ C iaricai tftsVriS/D.SVc: - 469:and 16 U.S.C. '0 et seq.O... ." "_ - - - - - / . : ~ . ,___... . -^-y.

46

A R 3 I !693

In summary, Alternatives 4, 5 and. 6 would comply with all ARARsassociated with drinking water (MCLs and non-zero "MCL'Gs)., surfacewater (State water quality standards, federal water..:qualitycriteria, and federal and State requirements pertaining to point"source discharges) and air (State regulations, pertaining' to ~ ,hazardous air pollutants and air quality and federal air emissionstandards for process vents). Alternatives"4 through 6 wouldalso comply with State landfill clos.ure"".ahd well construction andabandonment requirements, and all ARARs pertaining to hazardouswaste management (federal and State hazardous wasteidentification requirements, federal' land disposal re'strlctions,"and State requirements pertaining to generators and... transporters.of hazardous waste). In addition, Alternatives 4 through 6 wouldcomply with federal and State regulations pertaining; to sensitiveenvironments and natural and historic, resource's. Alternatives 5and 6 would further comply with federal.and State. requirements ,associated with storage of. hazardous waste. in addition.Alternative 5 would comply with federal.requirements for. thermaltreatment of hazardous waste. . . . . . . . . . .-..._.._

9.3 Long—Tana Effectiveness and Permanence

Alternatives 4, 5 and 6 would reduce risks to acceptable levelsfor the .ground water pathway since the ground water, .extractionand treatment system would permanently remove the contaminants ofconcern from the aquifer which underlies the Site. ,._;: heref-o.re,Alternatives 4 through 6 satisfy the requirements for. long termeffectiveness and permanence with regard to ground water. Groundwater use restrictions affecting properties near the landfillcould be eliminated once the.ground water cleanup levels wereachieved for each of these alternatives.

Alternative 4 provides containment of landfill wastes and wastesin PVC sludge disposal Cells A and B/C ..through capping. Cappingis a proven technology; a properly-maintained cap would provide .long-term isolation of source materials, and risk reduction whenimplemented together with a ground water, recovery and treatment...system.

Alternative 5 provides for the treatment of PVC sludge disposal -cell wastes by low temperature thermal desorption. "Thistechnology has the potential to provide a permanent reduction inthe concentration of contaminants that are available,forleaching. However, additional pilot-testing o_f; the. lpw_temperature thermal desorption process .would be required t'o._ensure that the technology is compatible with the PVC sludge andwould meet the cleanup level for vinyl chloride without„ :generating new chemicals in the waste material that may poseunacceptable levels of risk.

Alternative 6 provides off-site disposal of Cell'B/C wastes, and

47

A R 3

would permanently eliminate/one of '-the .sources' 'of. ground watercontamination 'at Y=t"he"lSite~ -^ --- •- ---^ -;"--*•- — - -

Treatment: and "Off'-sTte /d'Isp'o.sa /of ; te. PVC "sludge wastes{Alternatives. 5-;and'"6)' Would not provide,: slgnif-Ic,ant advantages .over capping ' lorie-:fAit.e"rhativ-e' •|)"" with_.respect to the activitiesrequired t"0 aiiiii""ta'i.ji:re£_:re/c.tiv:eness of .'.the remedy over time. Eachof ".these alterna-tiv-es±.woul_d reguir_e__loncr- e |& maintenance of thelandfill. 6a"p7"'"m-onTt6ring hetwbrks/'and deed restrictions .

9. 4 Reduction of Toxicity, Mobility, or Volume Through Treatment

AlternatlvesTT, "ancf 6~" would reduce,, the toxicity and volume ofcontaminated, -ground water" at .t£e,,_.Site//wi/tii.-.e_qual effectiveness .Although VOCs in gro'-iffird="wa~ter ;w;ould ultimately\be transferred toth.e. ambient.. .air, controls' for' "r"educi"n"g~"~t"he~"le"vel .of air emissionsto -the atmosphere, would be implemented if ..they were, determined tob& necsss-Sry^by EPA, in cons.ulta.tion-W.ith, MpE. .. in addition, thepre'cipita'tion, =flocculati"6n/ coagulation, and. carbon adsorptioncomponents, of "the' ground.- water.-_-tr:eatment .process would producecontaminated sludges, a'n :"mat_er4;als_ which _wQul.d have to. bedisposed of ...o±"f-sitev ;- / v " *'-'..*"-.."": ~~~' -'-"" :/-v--:-'-- " •- • •

Alternatives/4, 5'"and" F/would, each proyide..ln-place containmentof ...landfill ;'"w"astes""and_ coris.oiidatiqn _and ..cotttaj-nment of .mercury-contamina.t&d .soils, sitern'atiy-e- 4 provides 'In-place containment 'of •-Cell/S7Cr"'wastes "and .does not, reduce the toxicity or volume ofthes.e wastes., However, the. cap would decrease-the mobility o.f . .contaminants by reducing, the amount.of water that.may infiltrate.'the .wastes...and-".ca'uSe "certain' constituents to/ leach into groundwater— . _:---- —— '.:--L•T~r"'.:r. " " ' ' -!

AlterhatTvel """51"provides, for ".treatment", "o'f 'Cell B/C wastes .using lowtemperature.-thermal desorption.".: Xf-i h'e low temperature thermal. -treatment .process can "be...designed ,.a.nd. re.gulaj:.e_ql ..to, provideremoval o.f VOCs. w_ijt)ip .g ne..5s:t±;.(5ii_.."5t/t;oxlc 'by-products,Alternative./5 .' would provide .'a'' lo.ng-te'rm/_re '.iiti,Qn. in thetoxicity,'mobility and mass "of": confamina'ht's" "at the Site.

Alternative"..61 "ehtCIls o.ffp'site"'"l'andf111 .oUsposal- of Cell B/Cwaste-"mate:"ri-airs- and_ would; not g_e.sluit in any Overall', reduction of -toxicity" or volume"""bf. hazardous substances.'.' ' -

9.5 Short-term Effectiveness

Alternatives 4 -through 6 would_ jffect.iy.ey manage risk during .theconstruction d;;ilmpleLine;n=ta;t;i_cb"ii"/£ha"ses by ..employing controls(i .e.," gro.und' ater".-monitoring,; . de.ed and .ground water use,restrictions, arid alternate -water supply"or-polnt-of-entrytreatm_e~nt) until the time- that, cleanup .levels, .are 'achieved,thereby preventing, exposure 'to "coiitarnina''t"ed "ground "water in'.

48

695

residential wells. . . .

Implementation of each of these alternatives', would . present apotential for exposure "of workers to Site contaminants during capconstruction activities, installation^ of .ground water: monitoringand extraction wells, construction and, operation of ..the ground .water treatment system, and sampling activities.. Inr Addition,workers would be exposed to normal construction hazards.However, these risks' could be . reduced by following proper health..and safety practices for well . drilling, sampling and "construction.

Alternatives 4 through 6 also entail emissions of VOCs from theair stripper to ambient air. However, these emissions may beeffectively controlled with air emission control 'equipment inorder to .prevent unacceptable levels of exposure. ... .. ... ...

Alternatives 5 and 6 would pose an additional .short-term risk to..workers and neighboring populations as a result of the generationof dust and VOCs during the excavation and transportation of CellB/C wastes. There is. also the potential for .eXpos'ure tohazardous vapors in the event, of a malfunction of the thermaldesorption unit. These additional risks can" be reduced through.,.the Implementation of an air monitoring .program, emissioncontrols, the continuous monitoring of the thermal, treatmentsystem, and the incorporation of automatic shut-off features".

9.6

Construction of the fence, the landfill, cap and the. -ground watercollection and treatment systems would .be .easily accomplishedusing conventional methods and materials for each of Alternatives4 through 6. The ground water treatment technologies that wouldbe implemented under Alternatives 4 through 6 have beensuccessfully demonstrated in full-scale operations for thecontaminants of concern. However, treatabllity studies would be..necessary before remedy design in order to optimize- the treatmentprocesses and ensure that discharge of_treated grdurid_ water/to ;surface water would comply with the substantive requirements ofthe National Pollutant Discharge Elimination System program underSection 402 of the Clean Water Act, 33 U.S.C. § 1342, and wouldnot result, in an In-stream exceedance of, MCLs, non-zero MCLGs,State water quality standards, or federal ambient water. .-qualitycriteria for the protection of aquatic.- life", "l. --_-=---

Alternatives 5 and 6 would be more difficult to . implement thanAlternative - 4. Both of these .alternatives involve ..substantialexcavation of waste which would require^ additional .controls Inorder to minimize -VOC exposure to .workers. Low ..temperaturethermal desorption has been included in Alternative 5 as a .potentially feasible -technology for treatment" of" PVC~sludge

49

A.R3I 1696

wastes.... However," -pilbt-"tes'tin§ would'- be/required to . confirm thata suitable t_emp ratur.e./r ge;''exlst's_iai which the materials can besatisfactorily treated without creating hazardous PVCdecomposition products/. . Additional ..monitoring "and controls would•also vbe..required to., protect.against:.;poten"ti l...malfunction of thethermal -desorptlcm unit.. "" ~~" ' •'"""""-".'-." "-

Implementation O~f. "Alternative. 6 , would .depend upon acceptance of.the. PVC, sludge/ wastes.: by. an off -site disposal 'facility. Resultsof treatability testing, conducted during the Feasibility Studyindicate -.that the -Cell B/C/waste does .not/exhibit the toxicitycharacteristic of -a "hazardous waste and that . the material may beaccepted by a RCRA' Subtitle. D industrial waste landfill..However, in ' the event 'that future analyses /of ..excavated wastes .Indicate. :."that any portion O"f-lth.e material exhibits anycharacteris.ti, ._af;/ha;za;r:do.U.s/.wa.ste as. defined In 40 C.F.R. Part261, Subpart C, _that /portion o;f .the' material would have, to betreated. bn-site~,_or transported -to an off "--site"; _RCRA .Subtitle .C(hazardous waste) disposal . facility. "Yhis. situation would resultin delays in implementation .and additional costs/

The remaining" Lclo""mp15ne"n"ts:/of . 'Alli'ei na'Elves /4'' through 6. would not -.-present, any " marj 6£; llm l ntatiqn dijfli.cultie: . """. Ground water,stream and landfill ' gas monitoring would /be performed usingwidely practiced techniques.. Point-of-entry treatment systemshave been shown to., be effective in 'removing ;the" types ofcontaminants"-assdcla"te'd^ with_ this .Site..__^Resldeiitial well 'replacement, if necessity , wo Ul / e. '.c ndu. ted.in ..accordance withState- regulation :,- . "Co/operation" from property owners would benecessary ' f r ell/lihs'tallat'ipn,, " rna.intenance. ..ancL sampling . • -Ground vMejzil'uiSe" ^ In the areaof .the. Site : and mechanisms exist .w_i hln/the State and Countygovernments., f or::.ettf Orcemeht and "mociif ica.tion ' of. 'ground water .userestrictions :as ne6es"si.;ry" to nsur /jjirbtection 'of public health.Ground water -.use".: restrictions^ wbuld continue to be reviewed andrevised as additional .Site jiata' becomes available. . Future, use ofthe. landf ill. proper^ "can. be "effectively qontrolied through theuse ..of. deed .restrictions". ' """" . . . . . . .

9.7 Cost

-The' -present worth "of theT/ elected al aina.tlv .. (Alternative- 4) isest a i-a"t.r .a-f-8'26_,:0_.0Q.. ' Alternative; 4 is .less 'costly thanAlternatives 5 and 6 .but, provides . the .same -..degree of Ir riskreduction as /those alternatives, .//."".-/ .,.,-:/.": . . •-

9.8 State Acceptance

MDE has" not provided a letter "to. EPA " that" Vindicates whether ornot. the State .-GOncurs with the selected remedy. However, MDE hasexpressed -Co'n:c-ern...-EH"atrl-l;'"("l} several -of . the"" ground water cleanup

50

flR3!1697

levels set forth in the Proposed Plan for the ..Site,.are. more •stringent than the MCLs established under -the Safe Drinking WaterAct, 42 U.S.C. §§ 300f et seg.; and "(2) the. costs for ." ..implementation of the selected remedy may exceed ther costestimate presented in the Proposed Plan.' - :^

9. 9 Community Acceptance

Local residents expressed no opposition to most of., the elementsof the selected remedy. However, several residents ...have voiced ..their dissatisfaction with the ground water use restrictionswhich have been in effect at the Site since'1987 and "which wouldcontinue to be .implemented'until the ground water cleanup levels-have been achieved. The PRPs submitted comments regarding the 1landfill cap and the ground water cleanup levels identified.inthe Proposed Plan for the Site. Comments received during thepublic comment period concerning the Administrative. Record andthe various alternatives are summarized in the ResponsivenessSummary which is a part of this ROD.

10.0 SELECTED REMEDY: DESCRIPTION AND PERFORMANCE STANDARDS

Following review and consideration of the information in theAdministrative Record file, the requirements of CERCLA and theNCP, and public comment, EPA has selected, Alternative 4 .(Capping,Ground Water Extraction and Treatment, Monitoring, InstitutionalControls and Fencing) as the remedy for this Site. .Alternative ,4meets the threshold criteria of overall protection of humanhealth and the environment and compliance with ARARs, and 'provides the best balance of long-term effectiveness andpermanence, reduction of toxicity, mobility or volume ofcontaminants through treatment, short-term effective"riess,implementability and cost.

The selected remedy consists of the following major components: '

* Excavation and disposal of. soils .:fr"om .the "former drainfield of-the Transfer Station septic system

• Relocation of the current drain field of. .the TransferStation septic system.

Capping of the landfill and identifiable cells of PVCsludge

Ground water extraction

• On-site treatment of extracted ground water... and dischargeto the on-site stream

* Ground water, stream and. landfill gas." "monitoring

51

flR3i 1698

• Provision '6T K""a;KexnaEe/w¥te r'supply,. if necessary

Deed-.and ground water-..lisle""'"ire'stf'lc't.fons- " • "

• 'Perimeter,JLencllh"g" " ; - , - " • ":::" - --• -

Each c.omponent .dr/r.he £«me"d"y"an(l"iaan"dato.r.y performance standardsare .described below. . .

A. Excavation and Disposal of Soils from the Former Drain Fieldof the Transfer Station Septic System

An estimated..400 .cubic yards of mercuryrc_QntamInated soils shallbe excavated .from. th.e..:f-6rmef."drain field -of 1-the" Transfer Stationseptic-:sysreml. "Soil.-samples shall "be. collected and analyzed formercury -prior/to, excavation In /Or'def .ta .determine the exact areaand volume; of soils! requiring " reinoval. The .number and locationof soil samples" -and' the", analytical method.,.to be used shall bedetermined by EPA, in :c:gnsult"a"lii.Qn/.wl.1:h MDE/. Soils requiringremoval shall._be- subjected to. t_he Toxicity" CharacteristicLeaching" 'Procedure (T.CLP) as, described in 40,,. C", F.R Part 261,Appendix II, -"pridrc-~tor.-exc Ya"'t:i6n:'in 6rH"er- to! "determine whetherthose soils exhibit the-characteristic, of. toxicity.

Performance Standards for the Excavation and Disposal of Soilsfrom the Former Drain Field:

All soils containing greater ..than. 1 . mg/kg of mercury shallbe- excavated from:, the former, drain field.. . Excavated soilsthat are -found not to" exiiilp.it. -the characteristic of toxicityas defin"e:d:-in ""40 C.-F.R. § 26l. shall J>e disposed of nearthe- center, of the/Iandfiil/priorvto- Its , closure . Excavatedsoils, that a;re . found", to; exhibit the toxicity characteristicshall_ be disposed- of ' at 'a;"RCRA hazardous waste (Subtitle C)of f -si te" "disposal .facility and/ shall, ber managed on-site incompliance. With standards, applicable" to ..generators, of """ 'hazardous waste. ;( COMARs. 1QV51..,/0.'3. 01, /'/03, ".04, .05 and 06 "'[198.5,], and COMARs 26.13 ."03 . 01, '.03, ,04, .05, .06 and !o8)and transporters -O±//iia rd9lt s .waste_/-"(CQtiIARs 10.51 04 01.02", .03l..and;\0"4" [1985] , and COMARs 26. l3.'0""4 . 01, .02, .03and .040 _."•" The__federal_ land .disposal, restrictions . containedin 40 C.F.R. Part/ 2687 shall, also., ajppiy to 'the off-sitedisposal of. -any sdlls, fp'un to 'exhibit the toxicitvc h ' : ' ' " " r - • • • " -

B. Relocation of the Current Drain Field of the Transfer StationSeptic Sys tern

Prior to.lnstalla n teithe_:cap on theT.landfill,'"the septic- .system drain-;fxeld.which is currently in use"shall be' relocated

52

AR3!1699

from the west side of the Transfer -Station in order ..to preventthe discharge of liquids from the septic, system inta-areasoccupied by buried wastes. .. _

C. Capping of the Landfill and Identifiable Cells of PVC Sludge

Predesign studies shall be conducted in order to more clearlydelineate the boundaries of "the fill material, including. theboundaries of PVC sludge disposal Cells 1A and B/C. . A. capconsisting of a prepared subbase, gas. collection zone7, lowpermeability layer, drainage layer, cover material, topsoil andvegetative layer shall be placed over the'landfill .and identifiedcells of PVC sludge. A cap vegetation design and management planthat enhances habitat values, for migratory birds shall bedeveloped in consultation with the U.S. Fish and Wildlife ."..Service. The cap will cover an estimated 31 acres.' Theapproximate areal extent of the cap is shown in Figure- 4. Theactual areal extent of the cap will be determined by EPA, inconsultation with MDE, during the design, phase, based on datagathered during the RI and predesign studies. ... ...

Further studies shall be performed prior "to the design of the capin order to determine the landfill gas constituents and theemission rate. Cecil County, Maryland is.located in an areadesignated as a "severe-15" ozone non-attainment area under theClean Air Act. Therefore, if the landfill emits more .than 25tons per year of VOCs, reasonably available control technology(RACT), as defined in COMAR 26.11.19.02."G, shall be required-inorder to control landfill gas. EPA, in consultation with MDE,will determine during the remedial design phase whether an activegas collection system is required in order to ;comply with Stateregulations governing air quality or .whether a .passive gascollection system will be sufficient to meet those requirements.

An operation and maintenance plan shall be. developed for the capand submitted to EPA for approval during the remedial designphase. Inspection and maintenance of the cap shall .continue foran estimated 30 years or such other time period that" EPA, inconsultation with MDE, determines toL.be necessary, based on thestatutory reviews of the remedial action which shall be conductedno less often than every five years from initiation" "of the , . .remedial action, In accordance with the EPA guidance, document,Structure and Components of Five-Year Reviews (OSWER Directive9355,7-02, May 23, 1991). Statutory reviews will be conducted .aslong as hazardous, substances remain on-site and prevent unlimiteduse of, and unrestricted exposure at, the Site, If"determined tobe necessary by EPA, the operation and maintenance.plan shall berevised after construction of -the cap has been completed. Therevised operation and maintenance .plan shall-be. submitted to, EPA"for.approval.

53

BR3TI70Q

Performance Standards for the Cap:

1. The cap shall beidesigned a'ncL constructed to .functionwith minimum maintena"ffce/ ''to"'"p3:pm"ote/ . drainage andminimize: erosion "of .the cover. 'arid to accommodate . -settling, so that the . cover' s.-lntegrity is maintained.

2. The cap .shall be constructed, in /compliance with '.all.locatiori-speci'flc lARARs.,. .including \ the Archaeologicaland Historical Preservation... Act of ""1974, 16 U.S.C.§ 469, the National Hlst.griO_.PEe:s:ervati.on . Act of 198.6,16""0'rsYC7 '§"§• "470 ' Vt '' geq /", the -Endangered -Species Act(16 U.S/C/ § 133-1; 50^ C?F..Hl.Part.J;oi} and federal andState. .rjejjuiatlpns for the. protection of .wetlands( ExecutiVe:-Qrder .11.9 9 0 Q and COMAR 08" . 05 .04).

.3, The -cap7 shall 1 completely coyer the landfill, PVC sludgedisposal. Cell B/C, and Cell A, if Cell A is found duringthe predesi-gn studies. r, ' . " '

4. The cap rshall consist ..of a.; prepared,:, subbase, a gascollection _zohe) /•a./ip.w/p-er'me-'abilit-y, layer, a drainagelayer, cover material, topsoil- and a vegetative layer inconf-Ormahcfe with the single-barrier.;. cap specifications - -presented in the EPA Municipal . Landjill. .Guidance. . Thecap shall. .also" meet, the landfill" closure caprequirements "of " COMARs 26. -04. 07./21 B " and E.

5. The low permeability layer of the, cap shall consist, of24 inches__of;;;clay with, a permeability less than or equalto l.-X 10.. centimeters' -per"' se'Cdnd (cm/sec) , or asynthetieuliner that is equally protective, asdetermined by EPA. The choice;of, materials for the low

. permeability layer' shall be made by EPA, "in consultationwith MDE, during the remedial design.

6. An actlW a .' collection RACT, shallbe installed, if. .EP.A, _ in consultation:.. with/ MDE,determines that/such a system is/ necessary in order to.comply with .the substantive portion^, of State'

' "ar quality/ CpMAs 26.11.06.02,03-,_ 'J36"f .OS/and^. 09;;. CO.MAR. .2:6-11, 15; and COMAR

" ',™__... ,,.- .-.. . , .. ..... .-, . ..... :_.__i--5!-- — — •- ...5-tr -..-1--1... j—-, di^w wwr__iri

26.11.19-.02-,.G) . If..£PA, in consultation" with MDE,determine^- that, an active g"as collection system willbe ne-cessrryin/'ofder to "comply with ..these ARARs,•na c; C.T irei rr^e; ~-i-i>!'1 1 -. _j_ J '_._ - • . ,-..-.---.,• _-.-!_ '

not,

passive gas-Collection;system'shalirbe-installed. Therequirements /fail-the ,"gas collection "/system: will "bedetermined, by EPA," in'consultation with MDE, durinaremedi s i H o c i n ^ - - • • - • . . . - . . - ....... . aremedial.design;

D. Ground Water Extraction

54

A R 3 I 170

Ground water, shall be extracted from the aquifer using acollection system of multiple recovery wells, the exact "locationand number of which will be determined, by EPA, in consultationwith MDE. At least one round of,samples shall be collected fromexisting Site monitoring wells during the p-redesign phase andanalyzed for volatile .and semi volatile. organic compounds",pesticides and metals, in order to. determine the extent -pf theground water contaminant plume at that ".time. Aquifer tests shallbe performed during the predesign phase in order tor-define .aquifer characteristics, if such tests are determined to be.. .- :,necessary by EPA, in consultation with MDE. " ". . ;

An operation and maintenance plan shall be developed for theground water recovery system and submitted to EPA for approval ._.during the remedial .design phase. Operation and maintenance ofthe ground water recovery system shall continue for an estimated30 years or such other.time period.as. EPA, in consultation withMDE, determines to be necessary, based on the statutory reviews . •of the remedial .action which shall be conducted no.less .oftenthan every five ..years from initiation of the remedial action inaccordance with the EPA guidance document, Structure-andComponents of Five-Year Reviews (OSWER Directive 93.55.,7-02, May23, 1991). Statutory reviews will"be .conducted as long ashazardous substances remain on-site and prevent unlimited use andunrestricted exposure at the Site. The operation and maintenanceplan shall -be revised after construction of the collection systemhas been completed, if it is determined to be-necessary by EPA..The revised operation and maintenance plan shall be. submitted taEPA for approval. . .• -

Performance Standards for Ground Water Extraction:

1. The number and location of recovery Wells will be .. .1determined by EPA, in consultation with MDE, during theremedial design phase and shall-be sufficient to controlthe migration of contaminants and to .achieve the groundwater cleanup levels listed in Tables 9 and. 10..throughout the area of attainment. The area ofattainment is defined as the area outside the boundaryof any waste remaining in place up to and including theboundary o f t h e contaminant plume. . . .

2- Recovery wells shall be installed in•accordance withState regulations governing well construction (COMAR26.04.04).

3. The extraction of ground water shall reduce the levels.of the contaminants of concern in the area of attainmentto the ground water cleanup levels listed in Tables .9and 10. The concentrations.of contaminants in ground

55

flR3I 1702

water beneath the area of any wastes left- in place.(waste.management area) need..pot meet the ground watercleanup levels.. "^However, tlie?"extraction of ground watershall- "reduce"the ""contaminant concentrations in theground "water^beneath the waste management-area so that.subsequent migration of cpntamin'ah.ts from this area willnot'-result. in an'excee'dahce" of .grQu'hcl water cleanuplevels, within the area of", attainment." The. points atwhich compliance"with the cleanup levels will be'. ..

• . measured, (points of "compliance) shall/include-1 all well ..locations included-in""tne'm'dnitoring program discussed :below. " . . . . . . . . .

If" s"amplin '15bhflrms t"hat cleanup levels^ have beenachieved jthroughou.t the area, .of attainment at the pointsof-'./clompilahce, -and that the concentrations of the - ...contaminants-.o-f"concern .remain" at or below cleanuplevels" for .12 cdhsecutlve^quarters,' operation of thecollection sy stein, can be suspended". If, subsequent to- ..the collection "system" shutd.own/"semi -annual monitoringshows ..that the. .concentrations of..._.contaminants of concernwithin "the area, of.. attainment" exceed the cleanup levels,the. collection system .shall be . restarted and groundwater, extraction shall continue .until the cleanup levels

• have, once-more been attained .for twelve consecutivequarters. -Semi-annual .monitoring "shall continue untilEPA,: "in "consultation with MDE, determines that the -contaminant concentrations have stabilized-at or belowt h e cleanup levels. • - - • - : - . - . . . . .

E. On-site"Treatment of Extracted Ground Water and Discharge tothe On-site Stream

Extracted ground water 'shall.be treated . o.n-site. in a three-stepprocess. The.first step shall entail precipitation andflocculation/coalgulatlori' 60" remoVe. manganese" and other inorganiccontaminants. In the "second step, the filtered effluent from the.precipitation ."unit shal.l_..be piped to, an air .stripper column forremoval of VOCV."--'Finally, the •ground^ wa'tejr 'discharged from theair., stripper"--shall- be passed through granular activated, carbon toremove ~semi volatile .organic compounds and any remainingcontaminants.- .' The treated ground water shall then be. dischargedto-;the strea~itrthat-cross.es the southern end'of. the Site.

Predesign' studies/'shallCrVe "performed; inJojrder "to^determine theconditions .and procedures-" requ'lre'd -to "meet"th.e...performancestandards." and comply .with the .ARARs set'forth below.

Air" emission "'"and dlsp€rs"ion" modeling 'and 'a" human health riskassessment shall be:-conducted during the predesign phase,in Orderto ..evaluate the risks, associated with exposure to emissions from

56

S R 3 I 1703

the air stripper. The risk assessment shall be submitted to EPAfor approval. EPA, in consultation with MDE, -will-determine theactual treatment conditions and emission control requirements forthe air stripper based on the .results of the predesign studiesand the risk assessment.

The management and ultimate disposition of treatment residualsshall be determined during the predesign phase.and is subject toEPA approval. Such management shall .entail treatmeh"t"and/ordisposal.

An operation and maintenance-plan shall.be developed for. theground water treatment system and submitted to EPAfor- approval during the remedial design phase.Operation and maintenance of the ground watertreatment system shall cohtlnue""for an "estimated30 years or such other time period as EPA, inconsultation with MDE, determines to be necessary,based on the statutory reviews of the- remedialaction which shall be conducted no.less often thanevery five years from initiation of ..the remedial.action in accordance with the EPA guidancedocument, Structure and Components of Five-YearReviews (OSWER Directive-9355.7-02, May 23, 1991).Statutory reviews will .be conducted as long ashazardous substances remain on-site-and prevent -unlimited use and unrestricted exposure at'theSite. The operation and maintenances-plan shall berevised after construction of the treatment .systemhas been completed, if "is "determined to benecessary by EPA. The revised operation andmaintenance plan shall be submitted to EPA forapproval.

The performance or" the ground water recovery and treatmentsystems shall be .carefully monitored on a regular basis.: If EPA,in consultation with MDE, determines that alteration of thesystem is appropriate, based on performance data collected duringoperation, the system shall be modified. These modifications mayinclude any or all of the following:

1. discontinuation of pumping at individual wells wherecleanup levels have been attained; - . _. -

2. alternating pumping at wells to eliminate stagnationpoints;

3. pulse pumping to allow adsorbed'contaminants topartition into ground water and facilitate aquifer - -~equilibration; and

57

A R 3 I 1701*

4. installation ..of .add!tionai'. recovery wells to facilitateor "accelerate., cleanup "of "thei, contamination.

The Performance Standards for the On-site Treatment of ExtractedGround Water and Discharge to the On-Site Stream:

l.--The collection, treatment and discharge .facilities 'shall. , be^constructed"land_sited in compliance with_ the. .. ..

regulreme'nts' -in'/the • Archaeologies/^ and HistoricalPres-erWtion Act ofM974, "16"' OVsTci. §"469, the National. .Historlc'./Preser.vation .Act o£..lSfiJ67 T6" U.S . C. §§ 470 etseg-vv" the . Endangered. .Species Act/[1:6/U,,S..C/ § 1531; "50/c;"FV6y"P"artf"4b2") and 'federal .arid State regulationsfor:.the..protection of wei:la.nds_.:{Executive Order 119900and. COMAR"__08,:. OH;,"04j',' .'\ ' " */.. .. . . . . .:_. . .. ,.

'2". The:, on.-sit'e treatment .system shall relduce contaminantlevels-ln 'the extracted .ground water , to concentrationsthat EPA, in/cohsultation with MDE., has determined: (1)<shall.-achieve.-compli.ance with State water, qualitystandards. (COMARs 26_."0%. OZ/03- . 03-3 }° and federal ambientwater.. quality criteria established" for:' t_he protection 'of"aquatic- life.. pursuant. to 'Section 31p4-pf' the Clean Water 'Act. (33:.D.S.C.- §. 1314); and (2) shall not /result in anexceedance .-o:f 'KCLs ..{40. C.F.R/ §§ 141.11-. 12 .and 141.61-..627" -arid non-zerorlMCLGs .(40 ~C. F.R."" §§ '14.1. 50-. 51) in thereceiving body of .water. ."" " : -- - '

3. Emissions from/ the air. stripper _shall_. not :result in an*'excess, l.ifetim.el./'.Cane;e,r .ris'k" greater ,than 1 X 10~6 for- ".exposed ..indlv;lduals-.:".":.Air_ emlsslOnl',controls shall beinstalled. If "E"E>A","" "in "consultation with MDE, determinesthat emissions' from" the. air" 'stripper -stack . could resultin such., excess life time 'cance/tr' risk... Air stripperemis"s-io;ns';_shall_ also ^eet^tliie/ substantive requirements .of:: State" re:g ;i]!a/t~ ^ a4_r pollutants(COMAR 26.11715), "federal, .air lemlsslqn standards forprocess- ..vents/ f 40 C..5/..R. Part .2.6:4, ' Subpart AA) , andStatC .regulations " pe;r_tain.ihg ,.t,o emissions of. VOCs (COMAR26,ll.Q.6lO-STt The 'EPA -guidance, .document, Control of AirEmissions.- from "Super-fund- Air" Strippers at' s'uperfund

Directive , 355. 0-2 8, June 15,_ - . ,1989J., shall-also. ] _con i'(ier edi4n/.4ete_rmining the needfor ali'"-:e s''slon'ircon"tr6lst"Vi''"""""'1" "~r /" "-." 1 " . "

Residual wasees'"'s:ha"ll Fe""eval-uated... in accordance with •the. hazardous waste: 'ident:i;fica"ti.oE/requirements- of" 40CVF.'R.. § 2 1..'Zl7 COMARs jd. 51. Q .10, . U and .12 (1985)/and COMARs. 2 .13 . 02 . 11, /'/l /and.' '/l / ~ On -site handlingofL any residual /wastes 'found to. .exhibit a characteristicof a hazardous. .waste shall comply with standards

58

A R 3 1 1 7 0 5

applicable to generators of hazardous waste (COMARs10.51.03.01, .03, .04, .05 and .06 [1985], and COMARs26.13.03.1)1, .03, .04, .05, .06..arid ..08.) "and.transporters of hazardous waste (.COMARs 10.51.04.01,.02, .03 and .04 [1985], and COMARs 26.13.04.01, .02,.03'and .04). The federal land disposal restrictionscontained in 40 C.-F.R. Part 26.8 shall alsO.rapply to anyoff-site disposal of residual wastes "found.,to exhibit acharacteristic of a hazardous waste. : . :...,.. ,

5. Discharge of treated ground water to-the on-site stream shall comply with the substantive requirements of Stateand federal regulations pertaining to point source;".-dlscharges to surface water, including dischargelimitations (COMARs 26.08.03,01: and .07), standards, forbest management practices.. (40 C..F.R. Part 125,Subpart K) and test procedures (40 C.F.R. Part 136) .

W. Ground Hat«r Monitoring

A ground water monitoring program shall be implemented during theremediation phase in order to evaluate the effectiveness of~the .ground water collection and treatment system in meeting cleanuplevels and to ensure protection of nearby residents. EPA, inconsultation with MDE, will determine the number -and location ofnew monitoring wells and'the exact location of the existingmonitoring wells and residential wells "to be included in theground water monitoring network during the remedial design phase."The frequency and duration of sampling and the analyticalparameters and methods to be used will.be determined .by EPA., inconsultation with MDE, during.the remedial design phase.

Annual monitoring of select residential wells, (interimmonitoring) began in May 1993 and shall continue until the post--construction ground water monitoring program begins. l"fdetermined to be necessary by EPA, in consultation with MDE, the .number and location of residential wells in the interimmonitoring program, the frequency Of monitoring, arid/or the.analytical parameters and methods to be. used for interimmonitoring activities shall be modified. ... . . : . ..:

An operation and maintenance plan for. implementation "of .the'ground water monitoring program and maintenance of _the groundwater monitoring network shall be prepared .and submitted to EPAfor approval during the remedial design phase. Monitoring andmaintenance shall continue.-for an estimated 30 years ""or suchother time period as EPA, in consultation with MDE, determines tobe necessary based on the statutory reviews of the remedialaction which shall be conducted no less often .than.every fiveyears from Initiation of the remedial action in accordance withthe EPA guidance document, Structure-and Components of Five-Year

59

flR3! 1706

Reviews: (G'SWE'K Directive"-. 93,5.5:/7-OT;~ May "237 1991)": ' Statutoryreviews' will -be.jc-onducte.d, as long as-- hazardous substances remainon-s±te and prevent, unlimited- oise . and . unrestricted, exposure atthe Site-,- -.;_ ;_-:.3 :- p: ; '~-:': -- ' :":" .=.=- -.""•-'-" ''"'.:C-"- -;-'~-_--" _:... :.:. ......

Performance Standards for New Monitoring Wells :

New monitoring wells' shall "be installed" in accordance withState .- e qfflr-emeTitsTifb.rlTweXl /-construction '(COMAR 26.04.04).

G. Stream and Wetland Monitoring

An unnamed creek, which is "a tributary :of 3asin Run, flows .acrossthe., southern .end ofl -the ".Site. "1 A post-construction stream andwetland monitoring program "shall ~b/e "implemented In order to: (1)evaluate .-Site.Jim-pa'cts cn the "unnamed "'Cireek and potential Siteimpacts ; on a;;;f.0rest_ed -wetland area ;, located along the. creek. .approximately ori_e""m;ile':"dpwn.s.tream. from Waibel Road; (2) identifyany changes, .in/ C'on:ditI6n£r 'in; the. stream or forested wetland dueto .implementation 5.f /the. selected ."reme_dy.; and (3) assess.__the needfor additional, .stream arid' wetland studies,. or -additional remedialaction.' . ' " " .""."""". - ".: :1 '"""^ "' - •" ' ""." " """ ;" : ---'=^™it-i--=-j- • . v

Surfacei/water""and isediment" samples.';..shall. Be/collected from •upstrearrrand downstream locations in the unnamed creek and fromthe- palustrine-'forested'1"wetland" that.,.Is., located along the unnamedcreek, approximately c-nVmlle "Idown's'tfearn "from"WaIbell Road. - Theexact, number and location of samples .will... be. determined by EPA,in consultation with MDE, during the-.remedial design phase.These samples" .shall'be^anaiyzed .for .volatile and semivolatile ".organic compounds, pesticides and. metals.. In addition, surfacewater .parameters -such as :tempe±.ature," dissolved oxygen^ pH,conductivity and .flow rate^ shall" be' measured at each' sampling'station.. -."Surface" "water";.sam"p"le;§ - from"'erac"h "station shall also- beanalyzed for .tptal.. S-Uspended 'solids, alkalinity and hardness.Similarly/ the ""te"inperature, oxidation-reduction potential (Eh) ,pH, conductivity and c O'lor . (a_s_det_erirtine_d_by comparison with theMunsell Soil 'Color Charts) of-"sediments" at" each'sample locationshall be measured^ "-Sediment samples-from each.sampling locationshall als'O ."be™analyzed for :total"organic carbon, grain size,percent. moistu :e""S"nd percent solids. -Biological monitoring of .aquatic--macroinvertebrates, in accordance with EPA's guidancedocument, Rapid. Bioassessment Protocol, for Use'in Streams .andRivers: - -Be'nthic-'Macr_o±nver~tebrates and_ Fish .(EPA/444/4.-89-OQ1,May 1989)", sh'alir'Be conducted twice a'yea'f for-the..first, year, of.post-cons-tructio .m.onitQring'.'an'd, _once":>' .year thereafter. .EPA, -in""porisul"tatioh with MDE, " will ".determine -the need foradditional ~s"tream studies ...o.r-;fur.ther/remedial/.action to .address -the ..quality of water". In" the unnamed. Greek based __on .the streammonitoring "data" and" the "following "conditions and .criteria:upgradient._.s:tr.e;am/;"con"dltioris, 'State wa"tej:__quality standards and

60

fiR3! 17

federal ambient water quality criteria. .EPA, in consultation .""with MDE, will determine the need fan additional stream :and --.wetland studies or further remedial action to address the qualityof the sediments In the unnamed creek or.the downstream wetlandbased on the stream and wetland monitoring data and the .followingconditions and criteria: upgradient stream conditions,. ApparentEffects Thresholds (AETs) and NOAA Biological Effects Range - Low(ER-L).

In order to establish a baseline for the long-term streammonitoring program, before construction., .of. the selected remedybegins, at least..one round of samples shall be collected fromupstream and downstream locations in the unnamed creek, includinga station in the forested wetland that is located about one /miledownstream of Waibel Road. These samples shall be analyzed..for .'the chemical and physical parameters., specified above. Inaddition, a macroinvertebrate survey shall be.performed for~~upstream and downstream locations in the unnamed creek and theforested wetland, in accordance with the methods prescribed.above. The stream sampling and macroinvertebrate survey shall beconducted in the late spring or early autumn.. EPA, inconsultation with MDE, will determine the specific.-number andlocation of pre-construction monitoring"points "during theremedial design phase.

E. Landfill Gas Monitoring

A network of soil-gas monitoring, probes shall.be installed aroundthe perimeter of the landfill in Order to" evaluate" the potentialfor off-site migration of landfill gas 'and to. "assess "the need forfurther remedial action to prevent.the migration of landfill gastoward residences near the Site. The number and location ofsoil-gas probes shall be determined by EPA, in consultation withMDE, during the remedial design phase. Samples shall be.collected from the gas monitoring probes., .on a quarterly basisuntil EPA, in consultation with MDE, determines that thefrequency of the monitoring should be changed or that landfillgas monitoring is no longer necessary.. .The soil-gas "samplesshall be analyzed for VOCs and methane. Additional remedial -action shall be required to control off-site migration oflandfill gas if EPA, in consultation with'MDE, determines that itis necessary in order to protect human health, welfare, "or theenvironment, or to comply with COMAR 26.04.07/21(5) (b), 'whichspecifies that the concentration of methane at the landfill-/: ;" :property boundary may not exceed the lower explosive limit formethane in air, or 5.40 percent by volume. " -~

I. Provision of an Alternate Water Supply, if Necessary

If EPA, in consultation with MDE, determines, that, any residentialwell is contaminated with Site-related contaminants at

61

flRJI 1708

concentrations that".exceed-the^.grougd^.water,'cleanup levels, analternate .water supply shall be predicted at that residence. . Thealternate-.water ".supply1 shall consist of :either wellhead treatmentat the point o.f. entry or" installation of a new well in an.uncontantin'ated are'a ro"f the. aquifer. 'The choice, of alternate .water supply -will- be .made" by ,EPA, in consultation with MDE.WeHhe'a'd. treatment may "include physical and/or chemicalproeesse-s . -'-The _cho.ice . of,.- the wellhead treatment...unit or processwill be/made "by EPA, in consultation with" MDE, and will be based.on the type and concentration.of -"cphtam'Inaht (s) detected.Wellhead .treatment unlts shall-be maintalhed according tomanufacturer^is specif^ications" S*ov:"tiiat.""tne contaminantconcentrations in the water exiting the treatment system remainat or-below .ground water., cleanup/ levels .;// An/operation andmaintenanee :"plah~"fol: .It'he 'wellhead treatment. systems shall besubmitted, to.. EPA f Or/appitroVa.!.":.:.—// " " 1 .""

.The. wellhead. treatment systems may result "in the production o.fresidual treatment "wastes".' These, wastes (e-.cj., spent carbonadsorption units ar'filtration media] 's'ha!l"t>e evaluated inaccordance-.With the haz.ardous_.'wast.e identification requirementsof ...4.0_._C::F.R". : §-"26r...Z47 COMARs ' 10 ..51. 02/'lD, ' Jll'- and .12 (1985) ,and - COMARs 2e TTTpT-Ti, /."112" and _'.l3 .....l/pn-sit'eT handling of anyresidual .wastes ."found, to" exhibit a.,._cha.racteristic of a hazardous •waste shall comply "with standards applicable to. generators ofhazardous waste-(COMARs 10.51.03. Ql, ,Q3,"/.'0'4, .05 and .06119.85,], and ^MARs" 26V13."03.6.1, \'0"3, .L04VT/05, .06 and". 08) and'transpo-rters' G .haz.ardous ".Waste (COHARs 1.0 . 5.1. Q.4 . 01, . 02, . 03- and.04 [19,85], and"j30MARs 26.13, U4..01, :fe/.,. b|. ;and .'. 04) . The 'federal-lahdl.disposal ..restrictions co^aineci in .40 C.F.R. Part "-268 shall also apply to, "any of f-site 7o!isposal of residual wastesfound to. exhibit .a characteristic -of "a .hazardous waste. " '

Performance Standard for Alternate Water Supply:

1. - A wellhead treatment -"system*"shall reduce theconcentrations' of the contaminants; "of "concern In theresidential, well water; to;the. _groun;d water, cleanuplevels!, in Tables. -5- and"""l0. /..'- ----- "

2. A replacement'^well shall be installed, in "anuncontaminated- portlori of. the aguife,r in o.rder to.proylde.ja' .sufficient .quantity of; water -which meets theground water...cleanup _levels, jdejji.tSied....in. Tables. 9 and10. Replacement" wells sjiall "be .installed in accordance

. with State rei UlremenTs/ fpr ..Well /construction (COMAR26.04.04y/' ' " ""/ """"": ""I/'."" - 11" "-"-

J. Deed Restriction

As s.oon as! ra.ctTcaB.le, restriction's, shall" be placed on the deed

62

flR3l 1709

to the Site (parcel 267) in order.to prevent installation ofdrinking water wells on the property and any f uture-Vuses of, theproperty that could compromise the effectiveness, of "the selectedremedy. The deed restrictions, shall remain in effect: until" EPA,in consultation with MDE, determines that they are no longerrequired to protect human health and welfare and the environment.

K. Ground Hater Use Restriction

MDE and the County currently restrict the use of ground water inthe area of the Site through restrictions.on .the installation ofnew water supply wells. These restrictions on the installationof new water supply wells will continue-to be reviewed andrevised as additional Site data becomes available and will remainin effect until the ground water cleanup levels have beenachieved throughout the area of attainment. Mechanisms :existwithin MDE and the Cecil County Health Department for theenforcement and modification of the ground water userestrictions.

Performance Standard for Ground Water Use Restrictions

The ground water, use restriction zone shall encompass thelandfill property (parcel 267), the area of attainment asdefined in paragraph IO^D.1, above, and an appropriate bufferzone. The objectives of these restrictions is to limit -thepotential for—exposure to contaminated ground water, and to .minimize the extent to which the contaminant plume could be "extended as a result of additional ground water use.. =:

L. P*rimet«r Fencing

A chain-link fence shall be constructed around the perimeter oflM_.the landfill property, excluding the Transfer. Station buildingand rear loading area, in order to prevent unauthorized access tothe Site. Plans for maintenance of the fence shall.be submittedto EPA for approval during the remedial design phase.

Performance Standard for Perimeter Fencing

1. The chain-link fence shall have a minimum height of sixfeet and shall be 'equipped -with locking gates.

2. The fence shall be maintained in a manner ..sufficient toprevent unauthorized access to,the landfill until .suchtime as EPA, in consultation with MDE, determines thataccess restrictions are no. longer required.. _

M. Ecological Actions

63

flR31 1 7 1 0

The Site_."..is:i"loHate"3 w_lt_hin the known rang;e_of .the .bog turtle(Clemmys "muhlenbergl) , which . is; .a ;ca.ftdidat_e. for. federal listingas- a^ threatened" species".". """A predesign Investigation shall beconducted by a qualified'. herpetologist in. order to determinewhether: _or~n~ot"bog turtles ...occur on the. Site and, if. they, arepresent/ ~wa"ys" to::avdld "or i nl:mliz:e</;d.ls'tu]:rjja"hce__qf,._.the turtles -durincpreiriedial/ "act"lon:/..~:ih "addition/-"' a habitat " impact analysiswhich evaluates, the potential-Impact of remedial activities on '•migr.ato_r.y bird. and....anad'rofti6usr-"fish habitats, .shall be preparedduring the predesign. phase, in; consultation, with the U.S. Fishand Wildlife/Servicey -and submitted to EPA for approval. Ifdetermined to/be -necessary' by -EPA, in consultation with MDE,detailed "habitat . restoration and replacement plans shall bedeveloped for EPA""a'pp"f dva'l during- the • remedial design phase, andImplemented .in order to._rec£ify any unavoidable, adverse effects - .of /remedial -.activities- "on ' the "U. S. Department of .the Interiortrust resource"habita.ts . " ~-

11.0 GROUND WRTER REMEDY IMPLEMENTATION( — — .— - — _— - ^ i._.-

This remedial, action shall restore, ground, water .to its beneficialuse, which at. this-.Site includes . its... use as, a drinking watersource. ". lt~-"ma"y" be.come' .apparent during implementation or; 'opera ti on: i.of -.the remedy that contaminant^ levels have ceased to" .decline and .are remaining' constant /at." levels higher than the.ground ..water. ..cleanup Revels over""" some ..""portion of the. area of. . ,attainment._ .If "E"PA,"Tri" "consultation .with.. MDE, determines that. . .implementation of ~"the, ."selected remedy demonstrates, withcorroborating- hydrogeologic". and. .chemical/ evidence, that it will /be technically impracticable', to _ achieve .and.. .maintain the cleanuplevels throughput .the;. entire". area 'Of : g'rolun!dr."wat"er".contamination,

• EPA may "require titat any or- all of "the f_qllowing measures betaken, for an" iridel-finitel period" of time, a.s'further. modificationsof. ,the in-p"lac"e

1. long-term gradient .control may' be_..provided by low levelpumping, as /a containment' m'ea"Sufe";"L ' " " " " •'

2. cleanup levels may be modified ; and .chemical-specific .'ARARs may be waived for those, portions, of the aquiferfor-:::w"hlc.h EPA," in consultation "with MDE, determines thatit is . technically impracticable, .to -.achieve further ••contaminant reduction;

3. -Institutional' controls may be modified or maintained torestrict, access" to" those "portions*'1 Of. the aquifer wherecontaminants, remain above; cleanup "levels; and

4. remedial-technalogi^es Lfor ";gro.uTnd wa'ter' restoration maybe- re e-traluated". " " "l"~ 7" . T -

64,

flRSI 17

The decision to invoke any or all of these measures may be madeby EPA, In consultation with MDE. If necessary, EPA will issue .an Explanation of Significant Difference's" or "3! ROD amendment.

12.0 STATUTORY DETERMINATIONS

EPA's primary responsibility at Superfun'd sites is.l.tix.undertakeremedial actions that are protective of. human health and theenvironment. In addition, Section 121 of CERCLA, 42 U.S.C.§ 9621, establishes several other statutory requirements andpreferences. These requirements specify that.when complete, theselected remedial action for each site/must /comply"withapplicable or relevant and appropriate-environmental standardsestablished under federal and state environmental laws (ARARs)unless a statutory waiver is invoked. The'Selected,.remedy alsomust be cost effective and utilize treatment technologies or:resource recovery technologies to the maximum extent practicable.Finally, the statute includes a preference for remedies that

permanently and significantly reduce the volume, toxicity or 4mobility of hazardous substances,. The following sections discusshow the selected remedy for this Site meets these statutoryrequirements.

12.1 Protection of Human Health and the Environment

The selected remedy protects human health and the environment bycontrolling exposure to contaminated ground water, soils and seepsediments and by reducing contaminant loading to ground water andlocal surface water. . . -

Capping and ground water collection and treatment will preventfurther migration of contamination from the Site and effectively.reduce contaminant levels In the aquifer. Consequently, thesemeasures will reduce the potential for- exposure to contaminatedground water and the potential for Site contaminants to enter theunnamed creek. Ground water.monitoring will provide data forevaluating the effectiveness of the remedial action and willensure that any unacceptable levels of-contamlnants-inresidential wells will be detected and addressed prior to andduring"the remediation phase.. If necessary, wellhead" treatment"will reduce contaminant levels to acceptable ground water cleanuplevels or well replacement will provide water from "ahuncontaminated portion of the aquifer, thereby reducing or ;"eliminating exposure. Ground water use restrictions will prevent.future exposure to contaminated ground water by limiting thefuture installation of wells in the contaminated aquifer untilground water cleanup levels have been achieved. Once the cleanuplevels have been achieved, the carcinogenic risk associated withexposure to ground water shall be within EPA's target risk rangeof 1 X 10"6 to 1 X 10~4 and there ..will be. no significant "potentialfor adverse noncarcinogenic health effects as:La result of :"~~:

65

flR3l 1 7 1 2

exposure to"""g"roiih"d Vatle'rl Cjl/e", the -tiajzard index Lshall. .be. lessthan or .'.ecua7! to./onej',.. ._./:/;.. ~. ,, =r.r.._::jz_.,//./.;/_.. .,,. — -.-.--r -:-_--- :

Stream monitoring" ri/d will provide, abasis - for ..additional.:, remedial action^ If/It is determined to benecessary" by EPA, ln" ebhsulta".tlon""""with' MDS, in order to mitigateSite impacts "6rf:the "stream. ..and. prevent off-site migration oflandfill gas . /.'Deed restrictions ..will prohibit on-site activitiesthat could -.compromise, -the . effectiveness, pf/. the _reme.dy or resultin unacceptable levels "of "expo sure to Site contaminants.

Air emis.sloris"Trbffi t:he -air . stripping .unit will .be reduced toacceptable,-_risJc-ba.sed- levels. by the installation _ of. emissioncontrols, if they are""determined"to"..be." necessary by EPA, inconsultation'."w.ith MDE. Treated . ground water which is dischargedto the unnamed ""creek will meet all .appropriate water, qualitystandards In order to~"-|5reven;t 'any 'adverse; environmental effects.Through. .monitoring,"' "iTi:g'tl:tuti:ona;Xl controls/and . treatment, thisremedy will be/ "protective 'erf: human health and the environmentduring and. .upon Completion of - the" remedial ;; action.

12.2 Compliance with Applicable or Relevant and AppropriateRequirements

The selected remedy shall, attain all_. action-', location- andchemical-specific .applicable or relevant and appropriaterequirements 'for-' the Site., which are listed "in Table 11... Also'.included/in ":'the table are; crl eria,-/;a;dvls'Qries or' "guidance "to be:considered" -{TBCs.} "for" Imple'mentaTxbn of. .this ' remedy..

12.3 Cost-Effectiveness

The selected., remedy, Alternative 4, -is cost-effective, in that itmitigates the risks" posed by thevrcjp.ntaminants associated, with the•Site,- -meets .""a"ll/.6t _rnrejjuireiiignts_ of _ CERC-IlA, and affords overalleffectiveness proportionate! ..to"/.the .cost, __ The estimated presentworth cost ..for the selected remedy is $23, 8'26, 000 . The costsassociated with! the. alternatives that did- not include ground

; water extraction T~and treatment, Altei.rnatives '2 and 3, are ' . -comparatively . lower ::($ 4, .4 3 6, 000 .and '$15,' 856, OdO, respectively)than the. costs o.f" the" selected. . remedy but those .alternativeswould not achieve""' all of- the • remedial" action objectives. Thecosts associated- with_ Alternatives 5 -ajR_cJ =6_a_re comparativelyhigher . ($3.0, 9=0"2;'aOrO*wan ""$37"/T.3X O C'/ respectively) .

12 . 4 Utilization of Permanent Solutions and AlternativeTreatment Technologies to the Maximma Extent Practicable

The. selected - remedy for the Site, utilizes, -permanent solutions .andtreatment technologies i .tcuthe. .^maximum extent practicable.Although Alte"-rn"a""t"iv"e" US/includes low temperature thermal '

flRSI 1 7 1 3

desorption of the volatile constituents of .Cell B/C "wastes andwould provide some additional level-.of .treatment, it provides, noadditional risk reduction as compared .with the- selected remedy .since both of these alternatives would attain the same groun^water cleanup levels and prevent exposure.to contaminated soils , .and sediments. In addition. Alternative 5 is more costly andwould require the same level of maintenance activities as theselected remedy, as well as Institutional .controls. -,..=._ :.. .

12.5 Preference for Treatment as a Principal Element

The selected remedy uses treatment as a. principal, element to,address the threats posed by contaminants in the ground water atthe Site. Wastes buried at .the site and contaminated/soils posea relatively low long-term threat and shall be managed with acombination of engineering and institutional controls.

3-3.0 DOCUMENTATION OF SIGNIFICANT CHANGES

The following changes have been made .since.the.Proposed Plan wasissued on May 26, 1993: " ,

1. The Proposed Plan presented .specific and unique .ground watercleanup levels for each of 20 contaminants.. • Based oncomments received during the public .comment period, EPA hasmodified the cleanup levels fOr.six'of the ground water :contaminants. The final ground water cleanup levels takeInto account background concentrations.of arsenic andmanganese and provide flexibility in meeting the groundwater cleanup levels for those chemicals ..that may result in"noncarcinogenic adverse health effects in exposed ..populations.

2. At least one. monitoring station shall be.slted-.in thepalustrine forested wetland that is located..along theunnamed creek approximately one mile -downstream of WaibelRoad.

3. A predesign study shall be conducted in order to determineif the bog turtle (Clemmys muhlenbergi) occurVat the Site.If the turtle is found to occur at the Site;," remedial".:' /!.'

activities shall be conducted in such a way as to avoid or./..minimize disturbance of. the turtle. . . . . .

4. A habitat impact analysis which evaluates the potentialimpact of remedial activities on. migratory bird .andanadromous fish habitats shall be prepared during the -predesign phase. Detailed habitat restoration, andreplacement plans shall be developed and implemented, ifthey are determined to be necessary by .EPA.

67

flR3! I7!U

List of References

Fbste-r, S.A. and P.C... .-ChrostowsJci, 198"61, "Integrated HouseholdExposure Model fO,r,Jllser -df.lTap" .Water".Contaminated with VolatileOrgan!c'-ChemicHls,_" presented .at the. 79th Annual Meeting of theAir Pollutioln" "CQhtral'-Ass.ocieLtion', Minneapolis, Minnesota, June22-27, 19-86:""" ————-——:•-.•—""-————.——_- ; • ' : • . - . - ; - . ;-.-. - - - - - - - -

Hannah, S.R., G.A.'Briggs, and..,R.P. Hosku, Jr., 1982, Handbook onAtmospheric,.GJ-ffiis'lcsn/^Atmospheric Turbulence and DiffusionLaboratory, NOAA. "" - - - - - - - - - - - .......

Summers, K.S:.~, "S._ Cherini" and C".. Chen, Tetra .Tech, Inc., 1980,"Methodology to.Report -the: Potential', for" Groundwater .: .Contamlha'tion Trom""^e6thermal/Fluid Releases", " "EPA/600/7-SO/117 . '

.Turner, D.B., 1"97"0, 'Workbook of Atmospheric.' Dispersion Estimates,Air Resources."Field Research Office", "Environmental Science • ..Services ::Adminis_tr.a.tlOh, U.S ." EPA "O'fflce. oF/Air ' Programs,Research T.riangle.."Park, North Carolina... '"; .:

U.S.' EPA,"" 198..4","""lR"apTd_/Asses"sm.er3.t of~~E~xpb~sure to~__ Parti cu.1 ate . ~Emissions -fdr-:5u~r:f'ace .C6''ntami:h§n ~'S t~esl Office""Of Health andEnvironmental Assessment, U". S". Environmental Protection Agency,Contract .No. 6S".~03-311-6-.'" ."""": :..= "/ ": '" ". .' i" ".'- :~ " . .. . "

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Table 1Constituents Detected in Site Ground Water Wells

Woodlawn Landfill, Cecil County, Maryland(Page 1 of 4)

ConstituentVolatiies (ug/L)

AcetoneBenzene2-ButanoneChiorobenzeneChloroethane -

1,1-DichIoroethane '1 ,2-DichIoroethane1,2-DichloroetheneEthylbenzeneMethylene chlorideTetrachioroetheneTolueneTrichloroethene -Vinyl chloride .Xylenes (total)Semivolatiles (fj.g/L)Benzoic acidDiethylphthalateDi-n-butyiphthalateBis(2-ethylhexyl)phthalateDi-n-octy!phthalate .Pentachlorophenol

Range ofConcentrations

ND1 0-600ND5"-4 "

^ : ND10-63"'""--=---- ND5-23

ND10-3

. --ND5-7ND5-410

ND5-3ND5-4

ND5-38

- - " • ND5-8ND5-12ND5-60

NDO.18-520ND5-13

ND50-100- ND10-24

ND10-4ND10-140

' . :-- ND10-2

ND50-7

Frequency ofOccurrence

4/159/15

~~~37l5- 4/15

o/-i co/lo

4/15

1/15

1/153/15

5/152/155/153/1514/185/15

6/4811/4822/4819/481/48

•1/48

95% UpperBound

Concentration

1152,5615.88.9.3

4.98d3.1777.5

2.592.9110.43.44

5.00

13.1126

5.53

29.46.704.14

18.1

5.04d

25.2d

See footnotes at end of table,

" " V """ ~ " AR3! (720

Table 1(Page 2 of 4)

ConstituentFluoranthenePyreneButylbenzyiphthalate

Benzo (a)anthraceneChryseneBenzo(b)fluorantheneBenzo{k)fluorantheneBenzo(a)pyrene1 ,3-DichIorobenzene

1 ,4-DichIorobenzeneNaphthaleneDimethylphthaSatePhenanthrene1 ,2-DIchlorobenzene2-Methylnaphthalene

AcenaphtheneDibenzofuranFiuoreneAnthraceneCarbazolePesticides (ng/L)AIpha-BHCEndosulfan 1

Range ofConcentrations

ND10-3

ND10-5ND10-2

ND10-6ND10-5ND10-5

ND10-6ND10-5ND10-4

ND10-4

ND10-2

ND10-1

ND10-10ND10-7ND10-3

ND10-19

ND10-15ND10-25 •ND10-4

19

NDO.05-0.19NDO.05-1.7

Frequency ofOccurrence

2/48

4/481/48

5/485/484/48

2/48

2/481/48

7/48

1/48

1/48

1/481/391/39

1/39

1/391/391/39

1/1

7/393/39 .

95% UpperBound .

Concentration5.02d4.995.04d

5.024.99

5.01d5.055,00

5.01d

4.87d

5,04d .

5.05d

5.275.13

5.03d

5.96

5.686,37

5.01d

19d

0.044

0.15

See footnotes at end of table.

R R 3 I I 7 2

Table 1(Page 3 of 4)

ConstituentHeptachlorGamma Chlordane

AldrinEndrin Ketone..Metals (mg/L)

AluminumArsenicBariumCadmiumChromiumCobaltCopper

IronLeadMagnesiumManganeseMercury

NickelSilverVanadiumZinc

Range ofConcentrationsNDO.05-0.082NDO.5-0.028

NDO.05-0.18•--"-• — ~NDO.i-0.024

NDO.2-1.84NDO.01-0.008

------ NDO;i-0.2i4

NDO.005-0.119NDO.01-0.0169NDO.05-0.0512NDO.025-0.0043

NDO.05-43.5NDO.003-0.2780.929-34.8

' ._ ._,0.1 12-24.2ND0.0002-0.0026

NDO.04-0.0152

NDO.01-0.0097, NDO.05-0 0202

"NDO.02-b.0994

Frequency ofOccurrence

2/391/39

1/391/39

10/15' 3/15

~ 14/155/157/159/153/15

14/15

3/15

15/1515/154/15

7/15

5/158/15

"-"" 10/15

95% UpperBound

Concentration0.0290.25d0,035

0,050d

0.4140.00560.1040.024

0.010

0.030

0.01 2d17.00.05315.78.76

0.00091

0.0179d0.00602

0.0203d

0.0396

See footnotes at end of table. -

.flR'3M722

Table 1(Page 4 of 4)

On-site ground water monitoring wells used for purposes of the Risk Assessmentinclude ITB-1, ITB-2, ITB-3, ITB-5, ITS-1, F-2, F-3, F-5 through F-10, B-2 through B-4,OW-1, OW-2, SW-1, and TSW-1 for semivoiatile and pesticide compounds; and ITB-5,F-2, F-3, F-5 through F-7, SW-1 and TSW-1 for volatile and metal constituents.

ND s Not detected at concentration shown. In some instances, constituents weredetected at trace concentrations below the detection limit. As a result, some of themaximum range values are below the detection limit.

The concentration of the 95 percentile upper bound of the mean calculated using one-half of nondetect values. In instances where the upper bound value was greater thanthe maximum concentration, the maximum concentration was used in the RiskAssessment

Maximum observed concentration was used in the Risk Assessment for potentialexposure to this compound.

flR'31 1723

Table 2Constituents Detected in Off-site Residential Ground Water Wells

Woodlawn Landfill, Cecil County, Maryland(Page 1 of 2)

95% UpperRange of Frequency of Bound

Constituent Concentrations Occurrence ConcentrationVolatilesAcetone ' - - ND10-10 3/21 7.60Xylenes (total) . ND5-1 1/21 3.34Vinyl chloride - -- --- - - • ; NDO.12-0.6 5/22 0.17Semivolatiles (ug/L)Bis(2-ethylhexyl)phthalate ND10-5 1/20 6.93d

Di-n-butylphthalate - - - v-------ND10-3- : -4/20 6.14d

Diethylphthalate - ND10-5 2/20 6.86dMetals (mg/L)Aluminum " NDO.2-0.051 14/20 0.0655d

Arsenic - - "' NDO.01-0.a02 1/20 0.0067d

Barium " 0.0046-0.0596 20/20 0.0268Beryllium - - - - - ---—-—-- NDO.005-0.0022 1/2.0 0.00344d

Cadmium NDO.005-0.0034 1/20 0.00352d

Chromium ND0.01-0.0072 10/20 0.00754d

Cobalt NDO.05-0.0154 4/20 0.0296d

Copper NDO.025-0.255 19/20 0.0875Iron NDQ.1-6.075 11/20 0.801d

Lead • NDO,003-0.0518 13/20 0.00684

e footnotes at end of table. *

A R 3 l \12k

Table 2(Page 2 of 2)

95% UpperRange of Frequency of Bound

Constituent Concentrations Occurrence ConcentrationMagnesium Q.412-6,12 20/20 4.26Manganese NDO.015-3.015 18/20 0.313

See footnotes at end of table.

A R 3 I 1725

Table 2(Page 2 of 2)

ConstituentNickelSilver

VanadiumZinc ,

Range ofConcentrationsNDO.04-0.0124

NDO.01-0.0032

-~'* NDO.05-0.0154NDO.02-0.0613

Frequency ofOccurrence

2/20

- 2/20

17/2016/20

95% UpperBound

Concentration

0.0263d

0.00668d

0.009760.0270

Off-site residential ground water monitoring wells include those on parcels 309, 487, 151,530-17, 380, 233, 509, 506, 252, 530-23, 516, and 501.

ND = Not detected at the concentration shown. In some instances constituents weredetected at trace concentrations below the detection limit. As a result, some of the maximumrange values are below the detection limit.

The concentration of the 95 percentile upper bound of the mean calculated using one-half ofnondetect values. In instance where the upper bound value was greater than the maximumconcentration, the maximum concentration was used in the Risk Assessment.

Maximum observed concentration was used in the Risk Assessment for potential exposure tothis compound. - - ..— ..- -._— ——— ___..-—

ND = Not detected at the concentration shown. In some instances constituents weredetected at trace concentrations below the detection limit. As a result, some of the maximumrange values are below the detection limit.

The concentration of the 95 percentile upper bound of the mean calculated using one-half ofnondetect values. In instance where the upper bound value was greater than the maximumconcentration, the maximum concentration was used in the Risk Assessment.

flR3l (726

Table 3Predicted Leachate Concentration of Constituents in Site Ground

Water From Subsurface SoilsWoodlawn Landfill, Cecil County, Maryland

(Page 1 of 2)

Constituents

Volatiles (pg!L)2-Butanone1,1-Dichioroethane1,2-DichIoroethane1 ,2-DichIoroethene2-Hexanone4-Methyl-2-pentanoneAcetoneChlorobenzeneChloroethaneEthylbenzeneTolueneXylenes (total)TrichloroetheneVinyl chlorideSemivolatiles (jig/L)1 ,3-Dichiorobenzene1 ,4-DichIorobenzeneBenzoic acidBis(2-ethyihexyi) phthalate

Cell B/CArea

-0.590.110.13'0.120.22

9.01.37

6.660.0280.012

0.120.0103,242

--

42.55.54

Areas of theLandfill

Excluding CellB/C

5.12----2.0

16.5

0.077- . .

0.0280.044

0.054--

1.10.899.330.21

S R 3 l I727

Table 3(Page 2 of 2)

Constituents.

ButylbenzylphthalateDi-n-butylphthalateDi-ri-octyfphthalateN-NitrosodiphenylaminePentachlorophenolPhenanthrene2-Methylnaphthalene

Cell B/CArea

0.013 ,"- •"

: 0.000260.460.0066 -0.0140.62

Areas of theLandfill

- Excluding CellB/C

0.0200.0067

0.0000054-

."

-

Ground water concentrations were modeled for the leaching of subsurfacesoil constituents Info the underlying aquifer. (See Tables 6-9 and 6-10 ofthe Ri Report for soil borings associated with each area).

Dash indicates this compound not detected within the designated area.

AR3!(728

Table 4Toxicity Values for Chemicals of Potential Concern

(Page 1 of 5)

Refer to notes at end of table.

Compound

1.1-Dichioroethane

1 ,2-Dichlorobenzene

1 ,2-Dich!oroethane

1,2-DtchIoroetnene

1 ,2-Dlchloropropane

1 ,3-DichIorobenzene

1 ,4-Dichlorobenzene

2-Butanone

2-Methylnaphthalene

4-Methyl-2-pentanone(MIBK)

4-Methylphenol(p-CreSOt)

Acenaphtnene

AcenaphUiylene

Acetone

Aldrin

Alpha-BHC

Anthracene

Cancer Inhalation Oral CSF Inhalation Rfd Oral RfdGroup CSF (mg/kg/d)'1'8 (mg/kg/d)a (mg/kg/d)a

(mg/kg/d)"1-

C - 1x10'1 1 x10'1

< 4X10"2 9x10'2

B2 9.1 x10'2 9.1 X1CT2

- . - ix10'2

B2 . - 6.8 x10'2 1.1X1CT3

- - — 4.2 x 1C'2 9x10"2'

C - - 1.4 x 1C'1 9x10'2lb

9x10'2 5x10"2

_ - _.._. 4X10"3'

- 2.X10"2 5x10'2

- - - --- 1x10*1' . 5x10'2

_ - _ . . . . _ 6x10-2

. „ , _ , . 3x10'2'

- - - 3x100|d 1X1CT1

B2 1.7X101 1.7x101 - •• - 3X1CT5

B2 6.3x10° 6.3x10° - - -

- - —— ... ... 3Xio"1 .

A R 3 I I 7 2 9

Table 4(Page 2 of 5)

Cancer Inhalation* Oral CSF Inhalation RfdCompound " Group CSF (mg/kg/d)-1 >a (mg/kg/d)a

(mg/kg/d)-1'

Arsenic " " A" "~™l".~5~xlb1 . 1.75 . -

Barium - - - - --_ - -- - ixlO"4

Benzene -—""""A 2.9x10"^ ~2.9x10"2

Benzo(a)anthracene " 62 """""" . . - . - . 1 .67 " - -

Benzo(a)pyrene B2 6,1 ...... 11.5

Benzo(b)fluoranthene B2 - — - ; "--:-"1.61 " -

Benzo(ghi)perylene , . ,. — -- -.— <*—.-— -=-ao.253f -

Benzo(k)fluorantliene B2 . - " ••"b".7~59f" ~

BenzoicAcid '".. . .= .. ' __..,..._ . . . ..,. -_--.-.-.--.-.. .--.- ..-- -.. ••-- v._^ --.

Beryllium ". V"B2 "8.4.xio0, 4.3 -

Bfs(2--r- -.-•- —— . ---82"."." -"": --1.4X10'2. v"= >..ethy I hexy I) phthalate . •..-". ." -"- -- - - - - - .: . ...---- -

Bromodichloromethane B2.. - - . — " 1.3 x10"1 ~

Butylbenzylphthalate C _..... .. . ..' .^ , . - '. '_ .

Cadmium ...... .--..-B1 6.3x10° _ --- - . - r -,

Carbon Disulfide . - . . . - _ - - = . • . _ - .- " "-— - : --:":v~"'"-r2.9x 10"8

Chlorobenzene — ....... - • - - - -- - — - -- 5x10'3

Chloroform - - "B2 --8.1x10'2 "6.1x10^3

Chromium (Total) " ~ -. - •-• - -^ - - - - . - - QjxIQ'7

Chrysene . , - - B2 - " • • " " 0.0506f " -

Oral Rfd(mg/kg/d)a

3X10"4

7x10-2

3x10"2'e

3x10'2'e

3x10'2'e

3x10'2'e

3x10'2'e

4x10°

5 x 1CT3

2x10"2

2x10'2

2x10"1

5x10^

1 x 10'1

2x10'2

1 x 10'2

1 x10°

3x10'2'e

Refer to notes at end of table. . .,,-•- . ------- - - .

/ 3 R 3 I I730

Table 4(Page 3 of 5)

Cancer Inhalation Oral CSFCompound Group CSF (mg/kg/d)"1'"

(mg/kg/d)'1'

Copper - - — -

Di-n-butylphthalate — - — 7

Di-n-octylphtha!ate - - -

Diethytphthalate - - —

Dimethylpnthalate - - - - — - -

Endosulfan - — _

Endrin ketone — - - -

Ethylbenzene — - — -

Fluoranthene — — —

Fiuorene _ __ „

Gamma BHC (Lindane) C -

Gamma Chlordane B2 1.3x10° 1.3x10°

Heptachlor B2 4.5 4.5x10°

Indeno (1,2,3-cd)pyrene B2 - 2.668f

Lead B2 - . -

Manganese - - -

Mercury - - -

Methytene Chloride B2 1 .65 x 1 0"3 • 7.5 x 1 0"3

N-Nitrosodiphenyiam!ne B2 • - 4,9 x to~3

Naphthalene - _ . __._

Inhalation Rfd Oral Rfd(mg/kg/d)a (mg/kg/d)a

- 3.7 x

- - 1 x

- 2x

- - - - - - - e x

_...-. . 1 x

- - - - 5x

- - - - - - 3 x

- 2.9 X10"1 1 x

- - - - - 4 x

4x

3x

-• 6x

5x

10'2'a

1C'1

io-2

1C'1

10°

10-5

io-4

10'1

io-2 -10"2

io-4

io-5

10"4

- - 3x10'2-e

— - - '

1.1X10"4 5x

8.6 X10"5 3x

8.6 x10'1 6x

"-".'•

4x

io-3

ID"4

io-2

-

10*3

iRefer to notes at end of table.

AR3! I73

Table 4(Page 4 of 5)

Cancer Inhalation Oral CSF 'Inhalation RfdCompound Group CSF (mg/kg/d)"1*8 (mg/kg/d)8

. (mg/kg/d)-1 •

Nickel - — - -

Pentachlorophenol B2 - 1.2 x10"1 -

Phenanthrene .- . .-. ... ._ ..—..-...,.. ' : ---- ' . -

Phenol' . _ - . - . - . _ - — - - - - - * . = - : . - - / _

PwranA .._ — -._-_:— -------- — — .-- - . . . - _ - " " _ -a ,- . , """"' .ryiciic . . — .- -- - =--•-- : — : - • - . ' ' •. -•- - ' * —

Silver - " - - ": ' - - - : -'--"'- " - - -.--.-•'"" = -_ . •

Tetrachloroethene " ~ ~ B2 - -"- i.82x 10"3 "5?1 x 10J2

Thallium ' ' " • — •' - ;-.-~--~-:''-— ----- - -~~ ~-.: :T" T-- r :-^

Toluene ... . .. '.". " - - - ~~^ -^~~— ..,..'._, ...... .^ -5jxto"1

Tffcrilorbethene ""."B2 1.7x10"2 " 1.1x10"2 ~

Vanadium . . " . " _ - = . • - - . , - . . , ~ .,-.. .-

Vinyl Chloride _A 2.9x10'1 __ 1.9x10°

Xylenes (Total) - - - - , _ - - - - - - .--—.._—-- — -g-;6-x- 1 Q-2

Zinc ' " ' - ~'~- r" ~"L -" -.;——_;--- .. ..- ,:..-- .. -^. --;;—— _..

. Oral Rfd(mg/kg/d)3

'2x10"2

3x10'2

3x,10-2'e

6x-10'1

3x10'2

5x10'3

1x10'2

' "7X-10"5

2 x '1 0'1

7x10"3

2x10°

2x10'1

Cancer Slope Factors (CSFs) and Reference"Dc ei" QRfflsJ obtained from U.S. EPA, 1991, Health EffectsAssessment Summary TaHes/ ualYY-l iTlJ.S1992);:. .::-".;_•. V ;:;::.___::,.:-:.;/'..;:_. .= ....;:--::,--.-:--.. ,-, .

Value for 1,2-Dichiorobenzene used as a surfcigate based on.analogy.

Value for Naphthalene used as a surrogate" based on analogy.

US. EPA, 1986, Superfurid Public Health Evaluation Manual (SPHEM), U.s! EPA 540/1-86/060.

Refer to notes at end of table. .. - _.—.. .-——.=-... ._.-__- ., .-..-__, . - . . . - .

AR3M732

Table 4(Page 5 of 5)

Value for Pyrcne used as a surrogate based on analogy.t

Calculated at Benza(a)pyrene relative potency equivalent level (Clements, 1988).

Value for Endrin used as a surrogate based on analogy.

Potential health effects associated with exposure to lead evaluated using "Users Guide for Lead: A PC SoftwareApplication of the Uptake/Biokbetic Model-Version 0.50," prepared by Environmental Criteria and AssessmentOffice, Office of Health and Environmental Assessment, U.S. EPA, Cincinnati, Ohio, January 1991.

A R 3 I 1733

Table 5

EPA Categories for Potential Carcinogens

EPA CategoryGroup A

Group B1

Group B2 .

Group C "

Group DGroup E . ".-.," iTi:

Group DescriptionHuman Carcinogen

Probable HumanCarcinogenPossible HumanCarcinogenPossible HumanCarcinogen

Not ClassifiedNo evidence

EvidenceSufficient evidence fromepidemioiogic studies to support acausal association betweenexposure and cancer in humansLimited evidence in humans fromepidemioiogic studiesSufficient evidence in animals,inadequate evidence in humansLimited evidence in animals and/orcarcinogenic properties in short-termstudiesInadequate evidence in animalsNo evidence in at least two adequateanimal tests or in both epidemioiogicand animal studies

A R 3 I I73U

Table 6Summary Health Risks and Hazards

From Exposure to Off-site Residential Ground WaterWoodlawn Landfill, Cecil County, Maryland

INCREASED LIFETIME CANCER RISKRoutes of Exposure

Receptor Ingestion Dermal Contact Inhalation Total

Adult 1.6 x 10"4 6.1 x 1CT8 2.6 x 10"7 1.6 x 1CT4Child 1.0 X10"4 4,4 x 10"8 4.6 x10'7 1.0 x 1CT4

NONCARCINOGENIC HAZARD INDEX

Routes of Exposure

Adult 2.3 0.000017 0.00012 2.3Child 2.6 0.000021 0.00036 2.6

Compound-specific cancer risks and hazard indices are presented in Appendix N of theRI Report, See Table 2 notes for wells included in off-site residential riskcharacterization.

Derma! contact with organic constituents in ground water while showering.

inhalation of volatilized constituents in ground water while showering.

A R 3 I !735

Table 7Summary Risk Estimates (Current Conditions) for Selected Child

and Adult Receptors Across Multiple Exposure PathwaysWoodlawn Landfill, Cecil County, Maryland

INCREASED LIFETIMECANCER RISK

Routes of ExposureExposure Scenario Ingestion/Derma! Contact Inhalation Total

Off-site Adult ' 1.6x10"* 4.9x10~7 1.6X10"4

Off-site Child 10 x 10"4 7.5 x 10'7 1.0 x 10"4

On-site Child 3,0 x 10* 2.4x 10'10 3.0 x 10"6

Child On-and Off-site / • " l.Ox IO*4 7.5 x 10"7 1 .Ox'10"4

1 NONCARCINOGENICHAZARD INDEX

Routes of ExposureExposure Scenario Ingestion/Derrhal Contact Inhalation Total

Off-site Adult3 2.3 0.25 2.6

Off-site Childb 2.6 0.56 3.2

On-site Child0 ' 0.12 """ " 0.00088 0.12

Child On-and Off-sited 2.7 "\ ' 0.56 3.3

Includes exposure to off-site residential ground water and surface soil particulates fromareas of tjie landfill excluding Cell B/C. -

Includes exposure to downstream surface water and sediments, off-site residentialground water, and inhalation of surface soil particulates from areas of the landfillexcluding Cell B/C. .=- —-,-,Includes Ingestion/derrnal contact with on-site surface soil, seeps (sediment and liquid),settling basin sediment, and inhalation of surface soil particuiates while trespassing onSite,." = - - .. : - : - . -^-:- ==-""- : - - ----- .---—- --,---=..

Assumes child living in nearby residential area also trespasses on Site,

736

Table 8(Page 1 of 2)

Summary Ground Water Risk Estimates (Future Conditions) forSelected Child and Adult Receptors

Woodlawn Landfill, Cecil County, Maryland

INCREASED LIFETIMECANCER RISK

Routes of ExposureExposure Scenario Ingestion/Dermal Contact Inhalation Total

On-site Adult-Leachate 7.3 x 10"2 5.0 x 10"3 7.8 x 10"2

On-site Child-Leachatea 4.9 x 10'2 8.6 x 10'3 5.8 x 10'2

On-site Adult-Existing 5.6 x10"3 2.3x10"* 5.8x10"3

On-site Adult-Modelled 1.4 x10"2 7.8 x 10"4 1.5x 10"2

Off-site Adult-Modelled 1.7x10"3 9.4 x 10"5 1.8x10"3

NONCARCINOGENICHAZARD INDEX :.

Routes of ExposureExposure Scenario Ingestion/Dermai Contact Inhalation Total

On-site Adult-Leachate* 0.46 0.0028 0.46

On-site Child-Leachate3 0.53 0.0084 0.53

On-site Adu!t-Existingb 50 0.021 50

On-stte Child-Existing5 59 0.064 59

Exposure to leachate-contaminated ground water using the Summers leachate model,assuming a well is placed on the Site. The mean vinyl chloride concentration in the Cell B/Csludge, based on the results for the 27 samples collected during the RI/FS, is 290 j g/kg.However, the predicted leachate concentrations for this exposure scenario are based on the95% upper bound concentrations for constituents in just 5 Cell B/C sludge samples. The 95%upper bound concentration for vinyl chloride in those 5 samples was 4.98 mg/kg. Therefore,the risks from exposure to leachate-contaminated ground water are overestimated.

Exposure to constituents currently present in the aquifer immediately below the landfill,assuming a well is placed in the center of the plume.

f l R S I I 7 3 7

Table 8(Page 2 of 2)

Exposure to modeled on-site vinyl chloride concentrations; 70 years in the future at the.higheston-site well (633 ug/L at well. F-6).

Exposure to modeled off-site vinyl chloride concentrations; 70 years in the future at the pointalong the site boundary predicted to have the highest concentration of vinyl chloride (75 ug/Lalong Waibe! Road east of Cell B/C). .

A R 3 I 1738

Table 9

Ground Water Cleanup Levels for Contaminantswith Carcinogenic Health Effects

Contaminant

1,2-DichIoroethane

Tetrachloroethene

Trichloroethene

Vinyl Chloride

Benzo(a)anthracene

Benzo(a)pyrene

Benzo(b)fluoranthene

Benzo(k)fhioranthene

Bis(2-ethylhexyl)phthal8ie

Chrysene

Peniachlorophenol

Aldrin

Alpha BHC

Heptachlor

Arsenic

MCL1OW5

5

5

2

-

(U

-

-

6

-

r--0.4

50

MCLG3(Hg/l)0

0

0

0

-0

--0

-0

--0

•

Cleanup Level(ng/0

1 (PQL)S

1.5 (Risk-based)6

5

1(PQL)

0.13 (PQL)

0.023 (MDL)7

O.I 8 (PQL)

0.17 (PQL)

6

1.5 (PQL)

1

0.01 (PQL)

0.013 (Risk-based)

0.0 16 (Risk-based)

1 (IDL)B or background9,whichever is greater

Carcinogenic4 Risk

1.4X10-6

1.0 X10-*

i.oxio-*2.4X10"S

2.6 XIO"6

9.2 X' 10"*

8.3 X lO"6

3.7 X ID"6

l.OX ID"6

2.2 X JO"6

2.7X-1CT6 -

2.0 X IO*

l.OX 10*

l.OX 10-*

2.1 X IO-5 10

1 MCL: Maximum Contaminant Level1 jAgfl: micrograms per liter3 MCLG: Maximum Contaminant Level Goal* Excess lifetime carcinogenic risk associated with the cleanup level.- PQL: Practical Quantitation Limit* Risk-based: cleanup level based on carcinogenic health effects'MDL: Method Detection Limit* IDL; Instrument Detection Limit* EPA will determine the background level of arsenic in the area of the Site based on predesign studies.10 Excess lifetime carcinogenic risk from residential exposure to 1 ug/L of arsenic.

f l R S I 1739

Table 10(Page 1 of 2)

Ground Water Cleanup Levels for Contaminantswith Noncarcinogenic Adverse Health Effects

Contaminant

Endosulfan I

Arsenic

Cadmium

Manganese ; , . " "T .-"".;

MercuryVanadium """ " ---------

"MCL' ""(ug/l)2

-

50 . ...

5

.

2

'-

MCLG3fog/I)

-

__ . .

5

'-

2

-

Cleanup Levelfog/1)

_4

_4

_1

_4

_4

_4

1 MCL: Maximum Cont'ahiinanfLever _______ ._._._,._ ..___T_ _ ..... ..._.. . . . . _ . -2 (ig/1: micrograms per liter • ____ ___-_.._._, -__..r._.. .......... ..--w;.- ,.., ._...- -.-.-. . •-3 MCLG: Maximum Con taminant'te vet Goal

4 Ground water cleanup levels for contaminants with noncarcinogenic adverse health effects, will be based on the RiskAssessment and developed in accordance with the following approach. EPA, in consultation with MDE, willdetermine background levels of arsenic and manganese in ground water in the area of the Site based on predesignstudies.. The background .levels of these two chemicals will determine which of equations (la) through (2b) beloware utilized to develop cleanup levels corresponding to an aggregate hazard index less than or equal to 1.0. Eachequation represents a'different possible" Site condition with regard to the background levels for arsenic andmanganese. . . . r". .— ". "Y:"^~ " -/!"--• - ~7~.~-- '--. -=-.J-!-=^ .,.-..\. -- - ..--.-.--- .,•--.-,- - - - - - ••-•---. - - ;

In each equation,

[Endosulfan I] = the cleanuup level for Endosulfan I in p,g/L .[As] , = the cleanup level for arsenic in. gg/L[Cd] ._. , .= the cleanup .level for cadmium. in. |ig/L

[Mn] . = the cleanup level for manganese in jag/L[Hgl ......_ =.. the cleanup level for mercury in ug/L[V] = the cleanup level for vanadium in u.g/L

The number in each denominator in equations (la) through (2b) below represents the concentration in jig/L of thechemical b the respective numerator which is associated . with _a _ha?ard_ quotient (HQ) of 1 .0 (i.e., a concentration of1 .6 ug/L of.Endosulfan T is associated" with a HQ of 1 .0). the HQs for 'these chemicals .are. presented in the baselineRisk Assessment ". , .-. -. '...'•'-"•'•*-- _....----...-— -•- . . . . .

The cleanup levels for all six contaminants will be set such that:

(la) [Endosulfan I]/1.6,t.[As]/9.3 + [Cd]/16 "+ [Mn]/I60 + [Hg]/9.4 + [Vj/220 < LO.

where [As] = 1 ig/L (the cleanup level for arsenic, pursuant to Table 9)[Cd3<5(ig/L - . , ,- V-,.,.:: :.,.., ,,_7,,t-. --. ,-;-

or,

flR3! 17140

Table 10(Page 2 of 2)

(Ib) [Endosulfan fl/i.6 + [Cd3/16 + [Mn]/160 + [Hg]/9.4 + [V]/220 < 1.0

where [Cd] < 5 jig/L[Hg]<2jig/L

and the cleanup level for arsenic shall be the background arsenic concentration, pursuant to Table 9

unless EPA, in consultation with MDE, determines that such cleanup levels are infeasible due to the naturaloccurrence of manganese in local ground water. If EPA determines that the ground water cleanup levels that wouldsatisfy equations (1 a) or (1 b), above, cannot be achieved because the background level for manganese approaches orexceeds 160 ug/L, the cleanup levels will be set such that:

(2a) [Endosulfan I]/K6-f [As]/9.3+ [Cd]/16 [Hgj/9.4 + [V]/220 < 1.0

where [As] - 1 \igfL (the cleanup level for arsenic, pursuant to Table 9)[Cd]<5[!g/L[Hg]<2ug/L '

and the cleanup level for'manganese shall be the background manganese concentration

or,

<2b) [EndosulfanI]/1.6-!-[Cd]/16 + [Hg3/9.4 + [V]/220<LO . . ._

where [Cd] < 5 jig/L[Hg]<2iig/L

and the cleanup levels for arsenic and manganese shall be the background concentrations of arsenic andmanganese, respectively.

EPA, in consultation with MDE, will determine which of conditions (la) through (2b) shall be used tocalculate the ground water cleanup levels for contaminants with noncarcinogenic adverse health effects based onthe background levels of arsenic and manganese..

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DescriptionUSGS, Element Concentrations in soils and Other SuriicialMaterials of the Conterminous United States

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Element Concentrations inOther Surficial Materials of theConterminous United StatesBy HANSFORD T. SHACKLETTE and JOSEPHINE G. BOERNGEN

U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 1270

An account of the concentrations of50 chemical elements in samples ofsoils and other regoliths

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON ; 1984

1R3I !750

UNITED STATES DEPARTMENT OF THE INTERIOR

WILLIAM P. CLARK, Secretary

GEOLOGICAL SURVEY

Dallas L. Peck, Director

Library of Congress Cataloging in Publication DataShsckiette, HanafordT.Element concentration* in sofls and other surfidal materials of the conterminous United State*.(Geological Survey professional paper; 1270)Bibliography: 105 p.Stipt.afDocs.No.: 119.161. SoO_—United States—Composition.L Boerngen, Josephine G. II. Title. III. Seriec

S68..A1S5 681.4T73 82-600084AACR2

For sale by the Distribution Branch, U.S. Geological Survey,604 South Pickett Street. Alexandria, VA 22304

A R 3 I 1 7 5 1

ELEMENT CONCENTRATIONS IN SOILS AND OTHERSURFICIAL MATERIALS OF THECONTERMINOUS UNITED STATES

By HANSFORDT. SHACKLETTE and JOSEPHINE G. BOERNGEN

ABSTRACT

Sample* of soils or other regoJIths, taken it a depth of approxi-mately 20 on from locations about 80 km apart throughout the conter-minous United States, were analyzed for their content of elements.In this manner, 1,318 o Tripling site* were chosen, and the resultsof the sample analyse* for SO elements were plotted on maps. Thearithmetic and geometric mean, the geometric deviation, and a histog-ram showing: frequencies of analytical values are given for 47 ele-ments.The lower concentration* of some elements (notably, aluminum,

barium, calcium, magnesium, potassium, sodium, and strontium) inmost samples of turfidal miteritl* from the Eastern United States,and the greater abundance of heavy metals in the same materialsof the Western United States, Indicate* a regional geochemical pat-tern of the largoct scale. The low concentrations of many elementsIn soils characterize the Atlantic Coastal Plain. SoOs of the PacificNorthwest generally have high concentrations of aluminum, cobalt,iron, scandium, and vanadium, but are low in boron. Soils of the

char»c±«ristfc of ChilfCtowt sampling sites and the Atlantic coast sitesof Connecticut, MaasadboetU, and Uaiae. At the State level, Floridahas the most striking geochemical pattern by having soils that arelow in th« concentrations of most elements considered in this study.Some smaller patterns of element abundance can be noted, but thedegree of confidence In the validity of these patterns decreases asthe patterns become less extensive.

INTRODUCTIONThe abundance of certain elements in soils and other

surficial materials is determined not only by the ele-ment content of the bedrock or other deposits fromwhich the materials originated, but also by the effectsof climatic and biological factors as well as by influencesof agricultural and industrial operations that have actedon the materials for various periods of time. The diver-sity of these factors in a large area is expected to resultin a corresponding diversity in the element contentsof the surficial materials.At liar begiiiuSiCTsetSSisdy (1961). few data were

available on the abundance of elements in surficial ma-terials of the United States as a whole. Most of theearly reports discussed only the elements that were ofeconomic importance to mining or agriculture in a

metallogenic area or State; and the data, for the mostpart, cannot be evaluated with reference to average,or normal, amounts in undisturbed materials becausethey were based on samples of deposits expected tohave anomalous amounts of certain elements, or werebased only on samples from cultivated f elds.We began a sampling program in 1961 that was de-

signed to give estimates of the range of element abun-dance in surficial materials that were unaltered or verylittle altered from their natural condition, and in plantsthat grew on these deposits, throughout the contermin-ous United States. We believed that analyses of thesurficial materials would provide a measure of the totalconcentrations of the elements that were present at thesampling sites, and that analysis of the plants wouldgive an estimate of the relative concentrations amongRocky Mountain region tend to have high concentrations of copper, ., . ,, , . ,, . . . , . , . . .

i. and rinc. Hia?mercury ccwentntk™ in surfidal materiaLi Sltes of &* elements that existed in a chemical formthat was available to plants. Because of the greatamount of travel necessary to complete this sampling,we asked geologists and others of the U.S. GeologicalSurvey to assist by collecting samples when travelingto and from their project areas and to contribute appro-priate data they may have collected for other purposes.The reponse to this request, together with the samplesand data that we had collected, resulted in our obtain-ing samples of surficial materials and plants from 863sites. The analyses of surficial materials sampled in thisphase of the study were published for 35 elements byplotting element concentrations, in two to five fre-quency classes, on maps (Shacklette, Hamilton, andothers. 1971).Soon after the publication of the results of this study,

interest in environmental matters, particularly in theeffects of contamination and industrial pollution, in-creased greatly. At the same time, technological ad-vances in analytical methods and data processing facili-tated measurements of geochemical and other parame-ters of the environment. In response to the need forbackground data for concentrations of certain elementsof particular environmental concern, the samples of sur-ficial materials that were collected for the first study(Shacklette, Hamilton, and others, 1971) (with some ad-

AR3!1752

ELEMENT CONCENTRATIONS IN SOILS, CONTERMINOUS UNITED STATES

ditional samples) were analyzed for other elements, andthe results were published in U.S. Geological, SurveyCirculars: for mercury, Shacklette, Boemgen, andTurner (1971); for lithium and cadmium, fay ShacklettSjand others (1973); and for selenium, fluorine, and arse-nic, Shacklette and others (1974).The collection of samples for this study continued,

as opportunities arose, until autumn 1975, resulting inthe sampling of an additional 355 sites that wereselected to give a more uniform geographical coverageof the conterminous United States. This sampling con-tinuation is referred to as phase two. These sampleswere analyzed, and the data were merged with thoseof the original samples to produce the results given inthe present report. In addition, the availability ofanalytical methods for elements not included in the ear-lier reports permitted data to be given on these ele-ments in the more recently collected samples.The collection localities and dates, sample descrip-

tions, and analytical values for each sample in the pre-sent report were published by Boemgen and Shacklette(1981). The elemental compositions of only the surficialmaterials are given in this report; the data on analysesof the plant samples are held in files of the U.S. Geplog-

Survey.

ACKNOWLEDGMENTSThis study was made possible by the cooperation of

many persons in the U.S. Geological Survey. We thankD. F. Davidson, A. T. Miesch, J. J. Connor, R. J.Ebens, and A. T. Myers for their interest in, and con-tinued support of, this study. The sampling plan wassuggested by H. L. Cannon, who also contributedanalytical data from her project areas and samples fromher travel routes. Others of the Geological Survey whocollected samples, and to whom we express gratitude,are: J. M. Bowles, F. A. Branson, R. A. Cadigan, F.C. Canney, F. W. Cater, Jr., M. A. Chaffey. ToddChurch, J. J. Connor, Dwight Crowder, R. J. Ebens,J. A. Erdman, G. L. Feder, G. B. Gott, W. R. Griffitts,T. P. Hill, E. K. Jeririe, M. I. Kaufinan, J. R; Keith,Frank Kleinhampl, A. T. Miesch, R. F, Miller, R. C.Pearson, E. V. Post, Douglas Richman, R. C. Sever-son, James Scott, D. A. Seeland, M. H. Staat?, T. A.Steyen, M. H. Strobel!, V. E. Swangon, R, R.H. (A. Tourtelot, J. D. Vine, and R. W. White. Wethank the following members of the U.S. Departmentof A&&"" * tuae gil Conservation Service for providingsoil samples rom areas in Minnesota: D. D. Barron,C. R. Carlson, D. E. DeMartelaire, R. R. Lewis,Charles Button, and Paul Nyberg.We acknowledge the analytical support provided by

the following U.S. Geological Survey chemists: Lowell

Artis, Philip Aruscavage, A. J, Bartel, S. D. Botts,L. A. Bradley, J. W. Budinsky, Alice Caemmerer, J.P. Cahill, E. Y. Campbell, G. W. Chloe, Don Cole,E. F. Cooley, N. M. Conklin, W. B. Crandell. MauriceDevalliere, P. L. D. Elmore, E. J. Finlay, JohnnieGardner, J. L. Glenn, T. F. Harms, R. G. Havens,R. H. Heidel, M. B. Hinkle, Claude Huf&nan, Jr., L.B. Jenkins, R. J. Knight, B. W. Lanthorn, L. M. Lee,K. W. Leong, J. B. McHugh, J. D..Mensik, V. M. Mer-ritt, H. T. Millard, Jr., Wayne Mountjoy, H. M.Nakagawa, H. G. Neiman, Uteana Oda, C. S. E. Papp,R. L. Rahill, V. E. Shaw, G. D. Shipley. HezekiahSmith, A. J. Sutton, Jr., J*. A. Thomas, Barbara Tobin,J. E. Troxel, J. H. Turner, and G. H. VanSickle.We were assisted in computer programming for the

data by the following persons of the U.S. GeologicalSurvey: W. A. Buehrer, G. I. Evenden, J. B. Fife,Alien Popiel, M. R. Roberts, W. C. Schomburg, G. I.Seiner, R. C. Terrazas, George VanTrump, Jr., andR. R. Wahl.

REVIEW OF LITERATUREliterature on the chemical analysis of soils and

other surficial materials in the United States is exten-sive and deals largely with specific agricultural prob-lems of regional interest. Many of the papers were writ-ten by soil scientists and chemists associated with Stateagricultural experiment stations and colleges of agricul-ture, and most reports considered only elements thatwere Ijnown to be nutritive or toxic to plants or ani-mals.Chemists with the U.S. Department of Agriculture

prepared most early reports of element abundance insoils for large areas of the United States. (See Robin-son, 1914; Robinson and others, 1917). The 1938 year-book of agriculture was devoted to reports on soils ofthe United States; in this book, McMurtrey and Robin-son (1938) discussed the importance and abundance oftrace elements in soils. Amounts of the major elementsin soil samples from a few soil profiles distributedthroughout the United States were compiled by the soilscientist C. F. Marbut (1935) to illustrate characteris-tics of soil units.- The use of soil analysis in geochemical prospectingbegan in this country in the 1940's, and many reportswere published on the element amounts in soils fromareas where mineral deposits were known or suspectedto occur. Most of these reports included only a few ele-ments in soils from small areas. This early geochemicalwork was discussed by Webb (1953) and by Hawkes(1957). In succeeding years, as soil analyses became anaccepted method of prospecting and as analytical

AR3! 1753

COLLECTION AND ANALYSIS OP GEOCHEMICAL DATA

methods were improved, many elements in soils wereanalyzed; still, the areas studied were commonly small.An estimate of the amounts of elements in average,

or normal, soils is useful in appraising the amounts ofelements in a soil sample as related to agricultural, min-eral prospecting, environmental quality, and health anddisease investigations. Swaine (1955) gave an extensivebibliography of trace-element reports on soils of theworld, and he also summarized reports of the averageamounts of elements as given by several investigators.The most comprehensive list of average amounts of rareand dispersed elements in soils is that of Vinogradov(1959), who reported the analytical results of extensivestudies of soils in the Union of Soviet Socialist Repub-lics, as weH as analyses of soils from other countries.He did not state the basis upon which he establishedthe average values; however, these values are presuma-bly the arithmetic means of element amounts in samplesfrom throughout the world. In their discussions of theprinciples of geochemistry, Goldschmidt (1954) andRankama and Sahama (1955) reported the amounts ofvarious elements present in soils and in other surficialmaterials, Hawks and Webb (1962) and, more recently.Brooks (1972), Siegal (1974), Levinson (1974), and Roseand others (1979) gave average amounts of certain ele-ments in soils as useful guides in mineral exploration.A report on the chemical characteristics of soils was

edited by Bear (1964). In this book, the chapter onchemical composition of soHs by Jackson (1964) and thechapter on trace elements in soils by Mitchell (1964)gave the ranges in values or the average amounts ofsome soil elements.Regional geochemical studies conducted by scientists

of the U.S. Geological Survey within the past two de-cades have been largely directed to the establishmentof baseline abundances of elements in surficial mate-rials, including soSs. Most of the earlier work investi-gated these materials that occurred in their natural con-dition, having little or no alterations that related tohuman activities, with the objective of establishing nor-mal element concentrations in the materials by whichanomalous concentrations, both natural or man induced,.could be judged. Some of these studies were conductedin cooperation with medical investigators who weresearching for possible relationships of epidemiologicalpatterns to characteristics of the environment. In onestudy, the geochemical characteristics of both naturaland cultivated soils were determined in two areas ofGeorgia that had contrasting rates of cardiovascular dis-eases (Shacklette and others, 1970). In an extensivegeochemical study of Missouri, also conducted coopera-tively with medical researchers, both cultivated andnatural soils were sampled. The results were presentedfor the State as a whole, and for physiographic regions

or other subdivisions and smaller areas, as follows:Erdman and others (1976a, 1976b); Tidball (1976, 1983a,1983b); and Ebens and others (1973). The results ofthese studies, and of other regional geochemical investi-gations, were summarized and tabulated by Connor andShacklette (1975).Recent regional studies of soil geochemistry by the

U.S. Geological Survey related to the development ofenergy resources in the western part of the UnitedStates, including North Dakota, South Dakota, Mon-tana, Wyoming, Colorado, Utah, and New Mexico.These studies established regional geochemicalbaselines for soils, both in undisturbed areas and inareas that had been altered by mining and related ac-tivities. Some of these studies considered the elementsin soils both as total concentrations and as concentra-tions that were available to plants of the region. Theresults of these studies were published in annual prog-ress reports (U.S. Geological Survey, 1974, 1975, 1976,1977, and 1978). The data on soils, as well as on othernatural materials, in these reports were summarizedand tabulated by Ebens and Shacklette (1981). In astudy of the elements in fruits and vegetables from 11areas of commercial production in the United States,and in the soils on which this produce grew, soils wereanalyzed for 39 elements, as reported by Boemgen andShacklette (1980) and Shacklette (1980).The average amounts of elements in soils and other

surficial materials of the United States, as determinedin the present study, are given in table 1, with theaverage values or ranges in values that were reportedby Vinogradov (1959), Rose and others (1979), Jackson(1964), Mitchell (1964), and Brooks (1972). The averagesfrom the present study given in table 1 are the arithme-tic means. Although the averages were computed bythe methods described by Miesch (1967), the values ob-tained are directly comparable with the arithmeticmeans derived by common computational procedures.

COLLECTION AND ANALYSIS OFGEOCHEMICAL DATA

SAMPLING PLAN

The sampling plan was designed with the emphasison practicality, in keeping with the expenditures of timeand funds available, and its variance from an ideal planhas been recognized from the beginning. Because thecollection of most samples was, by necessity, incidentalto other duties of the samplers, the instructions forsampling were simplified as much as possible, so thatsampling methods would be consistent within the widerange of kinds of sites to be sampled. The samples were

754

ELEMENT CONCENTRATIONS IN SOILS, CONTERMINOUS UNITED STATES

TABLE 1,—Average or -median contents', and range in contents, reported for elements in soih and other surficial materials[Data are in parts per million; each average represent* arithmetic maan; leaden (—jin figure columns indicate DO data available. A, avenge; M, median. <, leu '**•";

7* greater tfaaaj... „„,,_.,.„, .... .u- jsa———— -——— -- - ———— J—— . - , • •-,.; -.- - .'- .„ •• ;*•(•• ."- - '• !-.~ -*-•-•"' , ' • / - -

_. . • Rose, and others Vinogradov .This report (1979) (elements -C1959) Jackaon (1964) Mitchell (1964) Brooks (1972)

Element geoeheiaical averages from "Typical",' Range inprospecting) ' worldwide average, contents in

Average Range sampling) . or range Scottish sor- Average or,„....„,.-. ___ ..... _ ••-,. -—- — —- --- ;.. . - • - . . . - i -\ in values face soils range

Al ———— -——72,000 .700 - < 10,0" dO. —— •. ——— .**•*.*-*.;- *"«~— ' • •••-/• -71,300 . :. 10,000 - 60,000 — ———————————————————————————

fla ———— - -—380 10 - 5,000 ' " .300 ., (M) _ .. . . — T ——~ — ,—. —————— ™ — = ———————— .... 400 - 3,000 5006 ————— ; ————————— <5 r 5 6

C, total 25,000 """.. -600V .370,000 " —— »V- ™-*— ————————— •r'.A r '2,0,0-00 , - - ,.-Wt=— : ————————— - ———— •• ———— - —————————— • ——————— .Ca ———— - -24,000 100-320,000' " ————— --— ———— ——> -T' • -13,700 . . .7,000 ————————————— '• — '• ————————————Ce —— : —— ••-- —--—75 - ~~ " <l~5(f -JS>Q — - - — —— -=—« ————— ' ——— — — : —— — — —— '• ————— --•—— - —— ~ —— • —————————————— : ———————————————————Co ———— :._.-.... -'9.i <3 - 70 10 (M)

CE ————— - -•— -54 - 1 - 2,000 ' ' "' !"6-j"~~(HJ.~Cu ———— -- 25. .: <1 - 700 " ' , "IS" («)F ————— ..-===*_. -430 -<1D - 3,700' * Jbj3 (M) Ayu. —— -.- ———— : ——————————————————————————————————————

- 20-, ... -T -20. <10 - 100 20

Fe ————— -- 26,000 . . 100 ->100,bOO '-, . 21,000." (K)~ " ' 38,000 7,,000 - 42,000 . . 10,000 - 50,000

Hg ———— -- -••• - -'-:09. XO.0'1"- 4.6 ~ ' " "" 6.056 <«) - - ——— - - ' - ——— - - ———— - - »iJ I

,K ————— -15,000 .. 50 - 63,'Obo ' 11,000 (K) _..„ 13,600 400 -.28,000 ———————— > —————————————————— — -

j_g ——— 9,000 so - >ibd,ooo ——— ^ ™ ——— : — , --'--6-300 - . <6",ooo .. - ~*^ ——————————————————

Na ———— 12,000. <50Q.-.- 1.00,000 ———— ~ —— •- —— -*. ..—*.-•"".- • --6;300 ——— - ———————— i. —————— : ———————————————— : —————————

Sb ———— - 11 <10 - 100 15 <A) ._..__- ——— ' ' - '-" ----- -- ——— ——— ——N(j ———— 46 <7/0 -.-JOO .. .-r---, --....,-- -- — -----~- - -HI ———— - --19 <._; - 700 17 (H)P ————— -----430. . <20-^- 6,800 300 CH) -. , ' .Pb ————— -- -=; ---'19 <10 - 700 ' 17 tM) ————

Rb ———— -•- 67 ' <20 - 210 " --35 "00 .. -~-- .-.--S, tocal 1,600 <_00 '48,000 .. 100 - 2,000

>o ———————— : —————— - - 10 - 800 . " 40

—— -. ——— U —— — - -- - ————— - <20 - 80 10

S1 ———— .. sio.OOO 16,000 "--~<15~0,000" ————— r —— -—**—- —— - --— -3.30,000 ' . —————————————————————————————————————————————— •

Si ———— 240 <5 - 3,000 . 67 C.H) . . . ' 300 ———— ~ ———————— 60 - 700 300

U ————— - - -"--=-2,7 • 0.-29 - 11 " " " "~ I (A) ————,V ————— -- -80 <7 - 500 " 57 "(H)Y ————— - - - •- 25 . --<IO"-200 - - - ———————————————— _- . — -----

Zo ———— - 60 <5 2,900 : . . - 36 (H)Zl ———— ..._ 230 <20 - 2,000 , .270 (H)

1 Author1* u*age; generally uaed to indicate the scat co«aoal_r occur

collected by U.S. Geological Survey personnel alongtheir routes of travel to areas of other types of fieldstudies or within their project areas.The locations . of the routes that were sampled de-

pended on both the network of roads that existed andthe destinations of the samplers. Sampling intensitywas kept at a minimum by selecting only one samplingsite every 80 km (about 50 miles; selected for conveni-ence because vehicle odometers were calibrated inmiles) along the routes. The specific sampling sites

—————————————————————— : ———— . ——————————— = —— - 1100 —————————————— 20-250 100

--..=50... ————————————— — -- - 25-100 ————————————

300 " '"•— '" •' —— — ———— 200 - > 1,000 ————————————

ring value.

were selected, insofar as possible, that had surficial ma-terials that were very little altered from their naturalcondition and that supported native plants suitable forsampling. In practice, this site selection necessitatedsampling away from roadcuts and fills. In some areas,only cultivated fields and plants were available for sam-pling.Contamination of the sampling sites by vehicular

emissions was seemingly insignificant, even thoughmany sites were within 100 m or less of the roads. Col-

A R 3 i 1755

DATA PRESENTATION

lecting samples at about 20 cm depth, rather than atthe upper soil horizons, may have avoided the effectsof surface contamination on the samples. However, wehad no adequate way of measuring any contaminationthat may have occurred. fSee Cannon and Bowles,1962.) Many of the sampled routes had only light veh-icular traffic, and some were new interstate highways.Routes through congested areas generally were notsampled; therefore, no gross contamination of the sam-ples was expected.The study areas that were sampled follow: Wisconsin

and parts of contiguous States, southeastern Missouri,Georgia, and Kentucky, sampled by Shacklette; Ken-tucky, sampled by J. J. Connor and R. R. Tidball;Nevada, New Mexico, and Maryland, sampled by H.L. Cannon; various locations in Arizona, Colorado, Mon-tana, New Mexico, Utah, and Wyoming, sampled byF. A. Branson and R. F. Miller; Missouri, sampled byShacklette, J. A. Erdman, J. R. Keith, and R. R. Tid-ball; and various locations in Colorado, Idaho, Montana,South Dakota, Utah, and Wyoming, sampled by A. T.Miesch and J. J. Connor. Sampling techniques used inthese areas varied according to the primary objectivesof the studies being conducted, but generally thesetechniques were closely similar to the methods used insampling along the roads.In general, the sampling within study areas was more

intensive than that along the travel routes. To makethe sampling intensity of the two sampling programsmore nearly equal, only the samples from selected sitesin the study areas were used for this report. Theselected sites were approximately 80 km apart. Wheretwo or more samples were collected from one site, theywere assigned numbers, and one of these samples wasrandomly chosen for evaluation in this study.

SAMPLING MEDIA

The material sampled at most sites could be termed"soil" because it was a mixture of comminuted rock andorganic matter, it supported ordinary land plants, andit doubtless contained a rich microbiota. Some of thesampled deposits, however, were not soils as definedabove, but were other kinds of regoliths. The regolithsincluded desert sands, sand dimes, some loess deposits,and beach and alluvial deposits that contained little orno visible, organic matter. In some places the distinc-tions between soils and other regoliths are vague be-cause the materials of the deposits are transitional be-tween the two. Samples were collected from a few de-posits consisting mostly of organic materials that wouldordinarily be classified as peat, rather than soil.To unify sampling techniques, the samplers were

asked to collect die samples at a depth of approximately20 cm below the surface of the deposits. This depth

was chosen as our estimate of a depth below the plowzone that would include parts of the zone of illuviationin most well-developed zonal soils, and as a convenientdepth for sampling other surficial materials. Where thethickness of the material was less than 20 cm, as inshallow soils over bedrock or in lithosols over large rockfragments, samples were taken of the material that layiust above the rock deposits. About 0.25 liter of thismaterial was collected, put in a kraft paper envelope,and shipped to the U.S. Geological Survey laboratoriesin Denver, Colo.

CHEMICAL-ANALYSIS PROCEDURES

The soil samples, were oven dried in the laboratoryand then sifted through a 2-mm sieve. If the soil mate-rial would not pass this sieve, the sample was pul-verized in a ceramic mill before seiving. Finally, thesifted, minus 2-mm fraction of the sample was used foranalysis.The methods of analysis used for some elements were

changed during the course of this study, as new tech-niques and instruments became available. For most "ele-ments, the results published in the first report(Shacklette, Hamilton, and others, 1971) were obtainedby use of a semiquantitative six-step emission spec-trographic method (Meyers and others, 1961). Themethods used for other elements were: EDTA titrationfor calcium; colorimetric (Ward and others, 1963) forphosphorus and zinc; and flame photometry for potassi-um. Many of the elements analyzed in the 355 samplescollected in phase two of the study were also analyzedby the emission spectrographic method (Neiman, t!976).Other methods were used for the following elements:flame atomic absorption (Huffman and Dinnin, 1976) formercury, lithium, magnesium, sodium, rubidium, andzinc; flameless atomic absorption (Vaughn, 1967) formercury; X-ray fluorescence spectrometry (Wahlberg,1976) for calcium, germanium, iron, potassium, seleni-um, silver, sulfur, and titanium; combustion (Huf&nanand Dinnin, 1976) for total carbon; and neutron activa-tion (Millard, 1975, 1976) for thorium and uranium.

DATA PRESENTATIONSummary data for 46 elements are reported in tables

1 and 2. In table 1, the element concentrations foundin samples of soil and other surficial materials of thisstudy are compared with those in soils reported in otherstudies. Arithmetic means are used for the data of thisstudy to. make them more readily compared with thedata generally reported in the literature. These arith-metic means were derived from the estimated geomet-ric means by using a technique described by Miesch(1967), which is based on methods devised by Cohen(1959) and Sichel (1952). The arithmetic means in table

.VR3! !756

ELEMENT CONCENTRATIONS IN SOILS, CONTERMINOUS UNITED STATES

1, unlike the geometric means shown in table 2, areestimates of geochemical abundance (Miesch, 1967).Arithmetic means are always larger than correspondinggeometric means (Miesch, 1967, p. Bl) and are esti-mates of the fractional part of a single specimen thatconsists of the element of concern rather than of thetypical concentration of the element in a suite of sam-ples.

Concentrations of 46 elements hi samples of thisstudy are presented in table 2, which gives the determi-nation ratios, geometric-mean concentrations and devia-tions, and observed ranges in concentrations. Theanalytical data for most elements as received from thelaboratories were transformed into logarithms becauseof the tendency for elements in natural materials, par-ticularly the trace elements, to have positively skewed

TABLE 2. — Mean concentrations, deviations, and ranges of elements in samples of soils and other aurficial materials in the conterminousUwtedStates

and range* «re reported in part* per million (d**. )f ' and means and deviation* ire geometric except u indicated. Ratio, number of utnples in which the element was foundin njea*arabieeonceirt™tki» to number of sample* ajwly»d. <, leu than; >, greater than)

' ————— ._ - . .- .. ... .- --.-r- - -------- , - - - , , . . _

Element

Al, percent

C*, percent

F ————————Fe, percent

K, percent

Hg, percent

Ha, percent

S, percent-

Si, percent1

Ti, percent

ConterminousUnited State*

EstimatedDttvia- -rlttaiatlc

Hean tion nean

4.7- 5.2---26440-= -.63

-- .561.6.92

63-6.7 '

• 37"-172101.8

13

•-•"1.2• -.058— -;75

1.5--30 .

'-20- .44• 330 ._

~59

--9.3-40• 13 .260

-.12- -.48•-..-7. 5.--- -.-26

31

• 120.24

-- -- 3.6

•••-2*3.

•—2,6• • 4"8"130

2.482.23' .1.972.142.38

2.502-574.00

"2,19

-2.372.443.342.382.03

1.372.522.63.791.92

1.853.28-2,77 ----2.72 -3.27

1.751.682.31.2.671 .86

1.722.042.27-1.822.46

6.482.363.301.391.53

1.732.251.78I'. 791.951..91 '

7.2. . 7:233;. -". ,S80

.92

- ,85•.?-s_ ,-:-

7V'9.1

"5425.4302.6

.17

, .0891.-2

Hone3"7

24.90

550 '- .971.2-

11«

43019

67'.16,67

- 8.9.39

None1.3 .

240.29

2.78025'3.160

. 230

.Ratio

661:770' 728:_730_

778: 77B310:778

.- 11.3:220-250:2,50.

" 777=777.81:683

"698:778

7 73:7 78'778:778

. 598:6107 7-6: "7 7 7767:776

124': ill729:733169:246777:777.462:777

731:731777:7787.77:777

'•- -57V774744:744

. 418:771120:538747^778524:52~4'

221': 22434:22435:223"685:778

" 590:733"

250:250. 218:224" "778:778"

777:777195:195

'224: 22T778:778

754:764766:7667Y7i773

Western tfnl(vest of 96

- Hean

5.8. 5.5-. 23580

.68

.._.£L_

" " "" ~f.l'~

' 4 f '". 21.230

2.1— 16 "

'1.2.046.791.8

30

22 '..74

380 ' .~ .85'•-97

- 8.7361532017

69" '".13.478.2.23

30 ....90

200 '-- .229.1

. ' 70. •.. 22.-..

2.655

'160

Devia-tion

"2.QO1.93_1.991.722*30. ..

2.V74-2J7 .3". 05 .

., 1.711.97 '

2.192.072.1521.931.68

1.32" '2.332.55

- .71"1.89'

•"[.58-2.-21

- 1.98i. 171.95

1.821.762.102.331.80.

2.372.151.74

. 2.43

r. 5-70

2,11"2.16"1.731.49

"\"k 5.-si;95i.661.63-1.79

"""1-77

ted Statesith meridian) t

EstimatedObserved arithmeticranjte ae*n

'."xoTTo '<20--;• 7o

..... . <I<0.5.0,1.-

.. oVb'e.." <3

32'

- 0.1<5

<30

50.0330<3

0.05

<IO<70

7"40~". . ... <10

~ "~-<20<0.-08

<!<5

<D.l

- 15' ' CO. 1"""To"' 0.05

2.4

~~0.~68--","" 7

- <10. "-.<J- - V i.°"~ <20

- 97- 300-, 5,000- 15

- 11- 1.0. "...- "32- 300- 50

-" 2.GOO- 300-' 1,900- >10- 70

.-..4-.-6. 'r.

"- 3- 200

-.130- >10- 5,000,.- 7 • ..- 10 .

- 100- 3,00

- 4', 500 "''- ZOO.. —

- 210- 4.8- 2.6- 50-4.3 ,

-.44 '- 7.4 ,- 3,000- 2.0-31

.-"7-9 """"""- 00 .- 150 ,- 20- .2,100' - 1 , 500

-""7.0".29. .....670._... .97.

.86- 2.5"3.3"759.6 "'-

.56 ...274402.619

!._..Q65 ,- 1.2None37

25 """. '.1.0

48Q '. ' .. 1.11.2

104319

'46020

'74.19.629.6.34

Hone1.2- .

270'.26

9.8-----

"88 " "".253.6.-..65 '. ,

' 190 " ' ' "

Ratio .

450:'477521:527425:541541 : 541169:525

162:16?!'.514:514. 70:489'403:533

541:541523: 533,390:433.539:540431:540

130:131534:53490:153537: 537294:516

47?: 527.528:52853~7s 540'32:524363".- 4 49

'322:498-109:332-443.L540380:382422:541

107:13120:13131 : 131

.389:526'449:534

.'156:156

' "50 1 : 540540:540102:102

7130:330'-.516:541477:541!"452:486473:482'53:9:541

Eastern{east of.

United States96ch aerldlan)

Devia-Kean tioo

.. 3.34.B31290

.55

.621.5.34

63 .' 5.9

3313

.1.30 ,

9.3 -

1.1.031

- .681.2

29

17.21

260.32.25

10. 4611200 '14

43.10.52

6.5 ..30

34.86

53.28

7.7

2.143202.640220

2.872.561.882.35.2.53

2.18. 2.383.08 .,1.352.57

2.602.804.192.872.38

1.452.522.81.751.98

2.163.553.823.934.55

1.651.582.642.951.95

1.941.342.381.902.44

6.642.313.612.001.58

. 2.122.511.972.062.112.01

EsCiaatedObserved arithaetlcrange nean

' 0.7 - >10<0.1 - 73<20 - 15010 - 1,500-<! - 7

<0.5 -- 5.30.06 - 370 .01 - 28

. <150 - 300 '<0.3 - 70

, 1 - .1,000.<! - 700<10 - 3,7000.01 - >IO• <5 - 70

<0. 1 - 2.0. 0.01 - 3.4

<0.5 - 7.00.005-- 3.7<30 - 200

<5 - 140 .0.005 -.5

<2 - 7,000<!.- 15

<0.05 - 5

<10 - 50<70 - 300<5 - 700<20 - 6,800

. <IO - 300

<20 - 160<0.08 - 0.31a - e.8<5 - 3Q

<0.1 - 3.9

1.7 - 45<0.1 - 10<S - 700

0.007. - 1.5 .2.2-23

0.29 - 11<7 - 300

"<10 --200.<: - so<5 - 2.900

<20 - 2,000

5.'77.438420

,85

.852.6.63

76,9.2

. 52. 22360' 2.5J4

1.2'.121.2

37

22.46

640.79.78

.125118360.17

53.11.76

. 8.0.45

1.5.120

.35_ 8.6'

2.7.6.6253.3 -

_ 52. '290

Mean* are arithaetlc, deviation! are standard.

AR3! 1757

DISCUSSION OF RESULTS

frequency distributions. For this reason, the geometricmean is the more proper measure of central tendencyfor these elements. The frequency distributions for po-tassium and silicon, on the other hand, are more nearlynormal if the data are not transformed to logarithmsand the mean is expressed as the arithmetic average.

were able to divide the ranges of reported values for

as the mean. In lognormal distributions, the geometric

In geochemical background studies, the magnitude of „ . _ , . , ,- . ,,. , ,»««**«« +„ K« «__..Ij -_ j -T. _ - • ^ 4. many elements into five classes so that approximatelyscatter to be expected around the mean is as important on "1 , •-., . , „ - , , , ^w v -. jr * 20 percent of the values fell into each class. The limited«, «f{«« ««»„,_ *u: ** j *u- j - _- range in values for some elements, however, prohibiteddeviation measures this scatter, and this deviation may .,„ „ f „ ,, , ., _ ^' J the use of more than two or three classes to representbe used to estimate the range of variation expected foran element in the material being studied. About 68 per-_,„«. nf,, . „ , , , . i . j .. , Tj were drawn on the maps by an automatic plotter thatcent of the samples in a randomly selected suite should ••, , , * i •« *• * j *.ft.n ,™tuu, *v. «—•* jy,rT jiv n L _x was guided by computer classification of the data, m-fail within the limits M D and M-D, where M repre- r 'sents the geometric mean and D the geometric devia-tion. About 95 percent should fall between Mil? andAM)2, and about 99.7 percent between MIL? and M-EP.The analytical data for some elements include values

for 355 les rf of for rf ^ rf .

that are below or above, the limits of numerical deter- We were Me ofatain rf n moremination, and these values are expressed as less than(<> or greater than (>) a stated value. These data aresaid to be censored, and for these the meanwas.com- tta tjad metnods ^ ^ dements m „..puted by using a technique desmbed by Cohen 59) bromin ^ ^^ iodinej .^and apphed to geochemical studies by Miesch (1967). „. *' .. A.orh]_' *m»» i i r i i- (• . i oijiumi. outiui. uiiuiluiii.Inis technique requires an acyustment of the summarystatistics computed for the noncensored part of thedata. The censoring may be so severe in certain setsof data that a reliable a4justment cannot be made; withthe data sets used in the present study, however, nosuch circumstances were encountered. The use of theseprocedures in censored data to quantify the central ten-

of samples—permit the number of censored values, ifany, to be found that were used in calculating the mean.This number is found by subtracting the left value inthe ratio from the right,The distribution of the sampling sites and the concen-

trations of elements determined for samples from thesites are presented on maps of the conterminous UnitedStates (figs. 1-47). Figure 1 shows the locations of siteswhere four elements, bismuth, cadmium, praseodymi-um, and silver, were found in the samples. These ele-ments were determined too uncommonly for reliable

mean concentrations to be calculated. Each of the re-maining maps (figs. 2-47) gives the locations where anelement was found in a sample from a site and the con-centration of the element, shown by a symbol that rep-resents a class of values. By examining the tables offrequency for concentration values o

the total distribution. Symbols representing the classes

eluding the latitude and longitude of the sampling sites.A histogram on each map gives the frequency distribu-tion of the analytical values, and the assignment ofanalytical values to each class as represented by sym-bols.

gtraints of resources time prohibited

* j * *u * i* vi j- . ^ * t. j -,LI_ ments. Results of analysis of the plant samples thatof data that a reliable adjustment cannot be made; with were _ollected ^ soil ^ Fsites m *notthe data sets used in the present study, however, no ^ ^ .-rfiimu •in

Some elements were looked for in all samples butwere not found. These elements, analyzed by the

dency may result in estimates of the mean that are semiquantitative spectrograPhic method, and their ap-ower thin the limit of deterrnination. For example, m ^ lower d ectiogn £nitS) parts pertable 2 the geometnc-mean molybdenum concentrationin soils from the Eastern United States is estimatedto be 0,32 ppm. although the lower limit of determina-tion of the analytical method that was used is 3 ppm.Use of this procedure permits inclusion of the censoredvalues in the calculation of expected mean concentra-tions.

are as follows: gold, 20; hafnium, 10CF; indium, 10; plati-num, 30; palladium, 1; rhenium, 30; tantalum, 200; tellu-rium, 2,000; and thallium, 50. If lanthanum or ceriumwere found in a sample, the following elements, withtheir stated lower detection limits, were looked for inthe same sample but were not found: dysprosium, 50;

m. j , .... , . . . , , „ - , . . - ,. erbium, 50; gadolinium, 50; holmium, 20; lutetium, 30;The determination ratios m table 2—that is, the ratio tjM... ' qAn;^w^ n,,,i;,™f ., , . . . ,,,.,, , , terbium, aw; and thulium,of the number of samples in which the element wasfound in measurable concentrations to the total number

DISCUSSION OF RESULTSThe data presented in this report may reveal evi-

dence of regional variations in abundances of elementsin soils or other regoliths; single values or small clustersof values on the maps may have little significance ifconsidered alone. Apparent differences in values shownbetween certain sampling routes, such as some of thoseacross the Great Plains and the North Central Stateswhere high values for cerium, cobalt, gallium, and leadpredominate, suggest the possibility of systematic er-

1758

8 ELEMENT CONCENTRATIONS IN SOILS, CONTERMINOUS UNITED STATES

rors in sampling or in laboratory analysis. Some grosspatterns and some of lesser scale, nevertheless, are evi-dent in the compositional variation bf-rejjaliths, asshown in figures 2-47.The lower abundances of some elements (notably alu-

minum, barium, calcium, magnesium, potassium, sodi-um, and strontium) in regoliths of the Eastern UnitedStates, and the greater abundances of the heavy metalsin the same materials of the Western United Statesindicate a regional pattern of the largest scale. Thisvisual observation of the maps can be substantiated byexamining the mean concentrations for these two re-gions given in table 2. The abundances of these ele-ments differ markedly on either side of a. line extendingfrom western Minnesota southward through east-cen-tral Texas. This line is generally from the 96th to 97thmeridian, and corresponds to the boundary proposedby Marbut (1935, p. 14), which_jdivides soils.of the_United States into two major groups—the pedalfersthat lie to the east, and the pedoeals to the west. Mar-but (1928) attributed the major differences in chemicaland physical qualities of these two major groups to theeffects of climate on soils. A line approximating the 96thmeridian also separates the Orders, _ Suborders, andGreat Groups of mbist-to-wet soils in the EasternUnited States from the same categories of dry soils thatlie to the west, as mapped by the [U.S.] Soil Conserva-tion Service (1969). As shown in table 2, soils of theWestern United States have the highest mean valuesfor all elements considered in this report except for an-timony, boron, bromine, mercury, neodymium, seleni-um, titanium, and zirconium. The differences, however,probably are not significant for these latter elements,except for zirconium.Superimposed upon this large-scale compositional

variation pattern are several features of intermediatescale. Perhaps the most notable of these are the lowconcentrations of many elements in soils of the AtlanticCoastal Plain. Soils of the Pacific Northwest are high'in concentrations of aluminum, cobalt, iron, scandium,and vanadium, but low in boron, and soils of the RockyMountain region tend to be high in copper, lead, andzinc.Several small-scale patterns of compositional varia-

tion can be noted, among them the high mercury con-centrations in surficial materials from the Gulf Coastof eastern Texas, Louisiana, Mississippi, Alabama, andnorthwest Florida, and a similar pattern on the AtlanticCoast in Connecticut, Massachusetts, and Maine. Highphosphorus values occur in soils along a tine extendingwest across Utah and Nevada to the coast of California,then south-east in California and Arizona. At the Statelevel, Florida shows the most striking pattern by hav-

ing low soil concentrations of most of the elements con-sidered in this study.The concentrations of certain elements do not show

well-defined patterns of distribution, and the regionalconcentrations of some other elements cannot beevaluated because they were not present in detectableamounts in most of the samples, or because the sam-pling density was insufficient. The degree of confidencein regional patterns of element abundance is expectedto be in direct proportion to the number of samplesanalyzed from the region. As the observed patterns be-come smaller, the probability increases that the charac-teristics that form the patterns are the results ofchance.Some features of element-abundance patterns proba-

bly reflect geologic characteristics of the areas that thesoils overlie. Samples from most of the regoliths overly-ing basic volcanic rocks of Washington and Oregon con-tained higher than average concentrations of iron andother elements, as mentioned earlier. A few soil sam-ples with high phosphorus content are associated withphosphate deposits in Florida, and a single sample inMichigan with high copper content is known to be ofsoil that occurs over a copper deposit.These data do not provide obvious evidences of north-

south trends in elemental compositions that might beexpected to relate to differences in temperature re-gimes under which the surficial materials developed.There is, moreover, no consistent evidence of signifi-cant differences in element abundances betweenglaciated and nonglaciated areas (the general area ofcontinental glaciation includes the northern tier ofStates from Montana to Maine and south in places toabout lat 40°N.; see fig. 1).The world averages of abundance for some elements

in soils, as given by Vinogradov (1959) and by others(table 1), do not correspond to the averages of abun-dance for these elements in the soils of the UnitedStates, according to.the data presented in this report.The world averages are too low for the concentrationsof boron, calcium, cerium, lead, magnesium, potassium,and sodium in United States soils and other surficialmaterials, and too high for beryllium, chromium, galli-um, manganese, nickel, phosphorus, titanium, vanadi-um, and yttrium.The stability of values for concentrations of most ele-

ments seems to be satisfactory because the addition ofanalytical values for 355 samples of phase two of thestudy to values for 963 samples of the first phase didnot significantly change the geometric means and devia-tions of element abundance that were reported earlier(Shacklette, Boerngen, and Turner, 1971; Shacklette,Hamilton, and others, 1971; Shacklette and others,

R 3 i 1759

REFERENCES CITED

1973, 1974). Although additional sampling of the sametype as reported here might give a clearer picture ofsmall-to-intermediate element-abundance patterns,mean values reported herein most likely would notchange significantly.

REFERENCES CITEDBear, F. E,, ed,, 1964, Chemistry of the soil [2d ed.]: New York,

Reinhold Publishing Corp., 515 p.Boerngen, J. G,, and ShaddetU, H. T., I960, Chemical analyses of

fruits, vegetables, and their associated soils from areas of com-mercial production In the conterminous United States: U.S.Geological Survey Open-File Report 80-S4, 184 p. Government Printing Office, p. 807-329.-1981, Chemical analysis of soils tnd other surficiai materials

of the contenninous United States: U.S. Geological Survey Open-

and bkjgeochemistry in mineral ex-ploration: New York. Harper and Row, 290 p.

Cannon, H. L., and Bowles, J. M., 1962, Contamination of vegetationby tetraathyl lead: Science, v. 137, no. S5S2, p. 765-766.

Cohen, A, C,, Jr., 1859, Simplified estimators for the normal distribu- O n-FUe Report 7&- p. 79-81. .-.-„;, -tion when sample, are singly censor*! or truncated: T_chnomet- ———1976' termination of uramum and thonum m U.S.G.S. stan-rics, v. l, no, 3, p. 217-S37,

Connor, J, J,, ind Shacklette, H. T., 1975, Background geochemistryof some rocks, soils, plants, and vegetables in the conterminousUnited States, with section* on Field studies by RJ- J. Ebens,J. A, Erdman, A. T. Miesch, R. R. Tldball, and H. A. Tourtelot:U.S. Geological Survey Professional Paper 574-F, 168 p.

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and R. R. Tldbalh U.S. Geological1237, 173 p,

Erdmin, J, A., Shacklette, H. T.. and Keith, J. R., 1976a, Elementalcomposition of selected native plants and associated soils frommijor vegetation-type areas in Missouri: U.S. Geological SurveyProfessional Paper 954-C, p. Cl-CST.

———1976b, Elemental composition of corn grains, soybean seeds,pasture grasses, and associated soils from selected areas in Mis-souri: U.S. Geological Survey Professional Paper 954-D, p. DI-MS.

Goldschmidt, V. M., 1964, Geochemistry: Oxford, Clarendon Press,730 p,

Hmwkes, H. E., 1957, Principles of geochemical prospecting: U.S.Geological Survey Bulletin 1000-F, p, 225-355.

Hawkes, H, E,, and Webb. J. S,, 1962, Geochemistry in mineralexploration: New York, N. Y., and Evanston. DI., Harper andRow, 415 p.

Huffman, Claude. Jr., uxiE Dinnin, J. I., 1976, Analysis of rocks andsoil by atomic absorption spectrometry and other methods, inMiesch, A. T., Geochemical survey of Missouri—Methods of sam-pling, laboratory analysis, and statistical reduction of data: U.S.Geological Survey Professional Paper 954-A, p, 12-14,

Jackson, M. L., 1964, Chemical composition of soils, in Bear, F. E.,ed.. Chemistry of the soil f2d ed.]: New York, Reinhold Publish-ing Corp., p. 71-141.

Levinson, A. A., 1974, Introduction to exploration geochemistry: Cal-gary, Applied Publishing, Ltd., 612 p.

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———1935, Soils of the United States, pt. 3 of Atlas of Americanagriculture: Washington, D.C., U.S. Government Printing Office,98 p.

McMurtrey, J. E., Jr., and Robinson, W, 0., 1938, Neglected soilconstituents that affect plant and animal development, in Soilsand men—Yearbook of Agriculture 1938: Washington, D.C., U.S.

Miesch, A. T., 1967, Methods of computation for estimating geochemi-cal abundance: U.S. Geological Survey Professional Paper 574-B,15 p.

Millard, H. T., Jr., 1975, Determination of uranium and thorium inrocks and soils by the delayed neutron technique, in U.S. Geolog-ical Survey, Geochemical survey of the western coal region, sec-ond annual progress report, July 1975: U.S. Geological Survey

dard 'rocks by the delayed neutron technique, in Flanagan, F.J., ed. and compiler, Description and analyses of eight newU.S.G.S. rock standards: U.S. Geological Survey ProfessionalPaper 840, p. 61-65.

Mitchell, R. L., 1964, Trace elements in soils, in Bear, F. E., ed.,Chemistry of the soil [2d ed.]: New York, Reinhold Publishing

Ebens, R. J.f Erdman, J. A.. Feder, G. L., Case, A. A., and Selby, M CorP-. p. 320-368.T A ,X™ n L r t M / i - r> n Myers, A. T., Havens, R. G., and Dunton, P. J., 1961, A spec-L. A,, 1978, Geochemical anomalies of a daypit area, Callaway _ . . , ... 1 , ^ • „-. _• , • * itrochemical method for the aemiquantttative analysis of rocks,

minerals, and ores: U.S. Geological Survey Bulletin 1084-1, p.U.S. Geological Survey Professional Paper 807,24 p. 207-229Ebens, R. J,, and Shacklette, H. T.T 1961. Geochemistry of some . „ „ 1D-~ * , • f , -, j i * u i.. , ,, _ ,, ,. ,-, T .. mj „„„,.„„ Neiman, H. G., 1976, Analysis of rocks, soils, and plant ashes byrocks, mine spoils, stream sediments, soils, plants, and waters .' . ' f ' ' *. ', , r r _ , , . , , _- TT -^j «*„*„„ emission spectroscopy. in Miesch, A. T., GeochemicsI survey ofin tht western energy region of the contenmnous United States, . l *y • ' f... _. ±: ..* „ ,, , _ ,, , . __ T r Missouri—Methods of sampling, laboratory analysis, and statisti-untk sections on Field studies by B. M, Anderson, J. G. * *' ^ «_ , • in„ . T _ OT - ~ - . w_jma^ r T cal reduction of data: U.S. Geological Survey Professional PaperBoerngen, J. J. Connor, W. E. Dean, J. _A- Erdman, G. L, S94_A

Feder. L. P. Gough, J. R. Herring, T. K. Hinkley. J. R. Keith, . 'J1' .B «f T-I T « « xi—i r- n »•___ or- Q*™«™ Rankama, K. K., and Sahama, T. G., 1955, Geochemistry: Chicago,R. W. Klusman, J, K IfcNwl, C, D. Rmgrose. R. C. Severson, ^ Univergity p , 912 pic composition of some important

American soils: U.S. Department of Agriculture Bulletin 122,27 p.

Robinson, W. 0., Steinkoenig, L. A., and Fry, W. H., 1917, Variationcomposition of soils: U.S. Department of Agricul-

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in mineral exploration £2d ed.]: London, Academic Press,658 p.

Shacklette, H. T., 1980, Elements in fruits and vegetables from areasof commercial production in the conterminous United States:U.S. Geological Survey Professional Paper 1178,149 p.

Shacfciette, H. T., Boerngen, J. G., CahiU, J. P., and Rahill, R. L.,1973, Lithium in surficial materials of the conterminous UnitedStates and partial data on cadmium: U,S. Geological Survey Cir-cular 673, 8 p.

Shacklette, H. T., Boerngen, J. G., and Keith, J. R., 1974, Selenium,fluorine, and arsenic in surficial materials of the conterminousUnited States: U.S. Geological Survey Circular 692, 14 p.

Shacklette, H. T., Boerngen, J. G., and Turner, R. L., 1971, Mercuryin the environment—Surficial materials, of the conterminous

A R 3 I 1760

10 ---"- ELEMENT CONCENTRATIONS IN SOILS, CONTERMINOUS UNITED STATES

United States: U.S. Geological Survey Circular 644, 5 p.Shacklette, H. T., Hamilton, J. C., Boerngen, J. G., and Bowies,

J. M., 1971, Elemental composition of surficial materials in theconterminous United States: U.S. Geological Survey ProfessionalPaper 574-0,71 p.

Shacklette, H= T., Sauer, H. I., andMiesch A, T., 1970, Geochemicalenvironments and cardiovascular mortality rates in Georgia: U.S.Geological Survey Professional Paper 574-C, 39~p.

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Siegel, F. R., 1974, Applied geochemistry: New York, John Wileyand Sons, 353 p. ... _ ...

Swain, D. J., 1955, The trace-element content of soils: England Com-monwealth Agricultural Bureau, Commonwealth Bureau of SoilScience Technical Communication 4S, 157 p.

•Tidball, R. R., 1976, Chemical variation of soils in Missouri associatedwith selected levels of the Soil. .Classification System: U.S.Geological Survey Professions! Paper 954-B, 16 p.

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annual progress reporC4S5>- 3tg5'. ~.-.j.}0.tfologicai"Survey Open-File Report 78-1105. 194 p.

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i\ R 31 i 7 6 !

12 ELEMENT CONCENTRATIONS IN SOILS, CONTERMINOUS UNITED STATES

'ZB° US' 12-" 122° ' 120° 118° 1]6° . 114' 112° Up". . 108°.. 106° 1Q4" 102C

.49(0.7)

40s.

50s

\

- ——— s PPR0"" DAKOTAx

C

SOUTH*

~ NEBRASKA

*4fff5) .,

\

'"D^ ' S -Cd(2)5 K^

c/) OKLAMEXICO

TEXAS

118° 116° 114" 112° , llff ... !08°..." I06f,._ 1M° ,i023 ~ 1ST

FiGUHE L—Location of sampling sites in the conterminous United States where elements not commonly detected in surficialdeposits were found, and the amounts of the elements present, in parts per million, in parentheses.

A R 3 1 1762

ILLUSTRATIONS - ^ . - _ . - . - - 13

92' ' 30° ' 88° 86° . ...84* '. _ .82°

ILLINOIS .INDIANA /

f

dU-5) .

TENNESSEE . _ .1

SOUTHARKANSAS'" - - - - - - - - —-——

0\J

I

46°

J44°

:" • . .1WISCONSIN . .. ........... _... .--. --- ------_. --—"-"." "^

MICHIGAN .. . -- . jXN S&ici* J40c

IOWA

-,3er

MISSISSIPPIpr(lOO)"

ATLANTIC^- -j 23°LOUISIANA . . ..... ._-

24°

J22°_ - - - . , - , . .-^_^—.,—r-- -• -,- •••-:. -*>->•*- • • t>"*lr-*S«!rt:JA "->*' "' .l:t.

...- -:---;j Junifeiffsr—-!jg4 rr!!! - J'!'.:'' ;j~-'±::.J:: = '':.-:. -'-'-':";-.g5J. -..-_i' _ jEnsb" J-K * •'.'.'._:. ''" '! ."32° 90°"" . 88°"."-'-- - 86° - "-W"' :" 82°. - .-,-'BD*..'" .'."_ "TB6 - - --76°"" " 74°

A R 3 I 1 7 6 3

18 ELEMENT CONCENTRATIONS IN SOILS, CONTERMINOUS UNITED STATES

128° 126° 1249 122* 120° 113° 116° 114° 112° 110° . 108°. 106° 104° I®» lOO

i8*

44"

42*

«• _ _ I- n ua _ a ' a Ba«

u nB

j *" n _""• t ~ B es N 1I~ U P! O ~ ~ ~ ' U! LI ° «o a _„ a a &QB "~ ~ .. H u _a B B a^h .«.fa-u *.a • a B BQOBS %Bd

a D u • a a H_y a M u

' - -u\ .; U°0/..S'U"3-W.736°L * • B "' a ua an . ' n a u n ..J " a a S a

H U _ \B • n .' sB B u •*•

34'

32*

__ —— 9" - Q- - UHg

V: >Y 7 HVu u u u e % ^ u B nav s _ " Ba= • a a fl——= ° - e a a = ^ a 0 ' -

ou .a • aaa ,, „ ° a' P- *- BS- •' .- ao BUB e'D= na .. au a a a _ 'a

'-—— B-_B u. a B /D u y -n _ u" u a a'~~ a i t _ n/ a "-1a - aa "u " = B/

BSYMBOLS AND PERCfcNTflSE v a ° J D O U'

OF TOTAL SAMPLES ,, ^ u 330* B 2Q*m 9 H „ a y a" £°"." "a °. S E =?

U DBB B L_ZnS .- - orH-l- - -",, B 3 °•g .. - u a"•% ° B°B J."

s sa a

•a B tL-H—,'%w a' x-aGeometnc mwrr 5.2 '-./ _l = H

G«onwric.svi»lion. 2.23 . . . . nNumber of samples and analyses U57 \ U

\ a">

•a• t

22*k____________._._.__________ i_______I ——L——————I———————L_118* 116° 114° lir HO6 108° .108° 104° 102s

FIGURE 4.—Arsenic content of surficial materials.

76U

ILLUSTRATIONS 19

94° . 92° """ so° -"88° :. w.'J84c'"..8r''Z.,'jJLJaT':"75t:'"' J JaL'v r -- "-si°: „". .e&'.. .,54°

J tj; u u >• = u u -a -n u u a a

.D... * ••*:•-*a u a- "ijH-s B _a • a."a u" . u -- u -". c:...__....._.•*—.. . u_... u . _. . u-..u .-, =

_ U B L J u . a U D -'B a • _ B ;• .- g H u d--°- u a "LJ u. -u. .u,=..a a«./~a. - a_--*-"-c^u° 'u u ,»———- - - v • au u

.. a . _-.u»—- •» ii*J ^ - .—-. - • — -— ———— -.,"-.D -~——^^- "'• " -""..u-1 "^B .u UjBi: --——- - ....--- -.w . - j y-

l- aSrT-- " ">-/- •" " -"--" -"---."---—- ------ -"-,g—— i- "" ' " •'" ' C

" ti\u, u .U' ^'-* U U U

• U . D

46°

44°

42°

40°

38g

36°

34°

32°

30°

28°

26°

22°

34° 92° "90° ". "88° "~"86° .". 84° 82" 80° . 78° 76° . 74*

K3I S765

20 ELEMENT CONCENTRATIONS IN SOILS, CONTERMINOUS UNITED STATES

12ff '25° 124' 122° 120° -118° .116° 114' .112°

Geomeirc meanGeometric deviation 1Nutnbflf ot samtfes and anaiysas 1.319

IN PASTS PER MILLION

118* 116° 114° 112° 110° 108°

FIGURE 5.—Barium content of stirficial materials.

-TR3I 1766

ILLUSTRATIONS O1£j.

767

34 ELEMENT CONCENTRATIONS IN SOILS, CONTERMINOUS UNITED STATES

128* 126° -124* 122° 12CT U8° HS° 114° 112* 110* 10B° 106° 104° 102° iQO°' • • - -

an a a -_ 9

irk. .. .—^-^-o-—e P _, ..

n TD a — , ,B H B U U a u

I —*_D upn. .?).:* :B -•" * °n •••[_! ^: - ,D a - • u «- - - - - c

wi. " u-. " ' a su u a u u o B B ^30"»- - - - - - - - • - a u . -d_3rr-=--f-Sir Ij u..-.u u ° u = u .

SYMBOLS AND PERCENTAGE OF TOTAL SAMPLES L*-~~-iJ— ..,_ ——~-U, 8 a 'U"T u-= a *_* — _ U ciH " u s o =25 222119 13 - \U U 's a H C

9BB , « __ . _ .. „ ... „ '-.B. .__U °"? .. a 0-

1 I ! » D ,,U B.u ° ~- n • a ...a . u " " *i • B H *

uGeooietnc moan- 37 \ U n uG«omeinccl«viMlon- 2,37 \ uNumber of sampw and analysw 1.319 ' U

*u au

U ._ --

--M«u»'-rSSgSSS8S|gi

AMOUNT. IN PARTS PEP. MILLION

: ——— —— w —— Tw' Tap- -. : i?F w us-.:. .«"• '*

FIGURE 12.— Chromium content of aurficial materials.

A R 3 I 1768

ILLUSTRATIONS . 35

" 66=.- • ^ ••"~ " •""" ' " * " ~ " - ' '

94° 92° 90°.;- 88° v. W''/-'&>:'-.-'('&':.•'-.:&-'--•-'w*' - fw

46°

•s

44°

42°

30°

28°

22°

74°

M R 3 - I 1769

52 ELEMENT CONCENTRATIONS IN'SOILS, CONTERMINOUS UNITED STATES

'28* 126° 124" 122° 120° 118° 1163 ]1.4; 112° 110° JQg" W "JTCl* 102"~——j—-——n————T^^——j--'—-- - , - - - . f 5——-f —--pr- ---j - [ j- - i

a . . . . _ . . .-__ _ _ . ...ua

«•: ° B U* - S H U

a a u S BB ** - u .. a

I* O U o" p_ U ° B "" " ,,3n

B a B a "" a U « • • - • " _a H a u°n a a a0" a ae Q B c „,_. n

«Y QaE? B B a- - u- -a- - •-«-" B a = a.-. ..-au • s B a a B =? BSauQ aa oa e u %

„ s u3 B u . a ' a a a o D_Q. __. _r"H_

«. u °° V"-** -B u . ; - Ona -Jo ^ - - „•r- ° s -a • u , ° a =: ^_ Bf, a a „

S = H _ _• UO n • • • _ U" a 0 - " . - B n

= " a a" "=-s' i-*- « C o= S B —— B e "a « ff.HB - DBBaB= "-^ H -•- ea s S B • B S = ' H e

- - C_S0 „• aaa.« ". -a. u o a u tf; :a ,° B ,Q QJi. -D ° ' =% =;° .Ga •.' u -..I- a e 9 9, » H _ a a " u B a a o s™- fS 3 " BQ S B B » BU a =• s "«• g B S . a B ° s

» s Q B " • • Ifca". ° —; - - a .SoGea«se-_3 «""B-BB ~\ H " - B ^ a a aa S" a-a. ..J " = • a S* - = • „ • • B s B .. ua % Ba ==•eBa •°aaBSt Q D u°-a- u---J.aa "aaa u« aa „, •:-.•-•-.-/. - B.V" r>. :\s:;.--

^- --" . SB BB ^Bg a BB a B l ? a as

- - ' °= BB = aV.'B* '. ,..u-'a u -• -aa . - a

'Z-~ "" " a S S 3 as a - - _B - B a . a a ° B ° u 0 B

' " = • a = u u ua _ s • u

s a « = H B a B - . nlO-V. SYMBOLS AND PERCENTAGE OF TOTAL SAMPLES a " s a ^ p ^ U ^ , C'* '6 3i »_^ga • ^ u - - ~ g a

,uui- a "y28V i , si • i - - u _

a o" u o.c- » °a B a a o

Geocnetrc mean 16 O_. . .... E -l Gwjmaltic OBv«tion 1 86 ° B p| Numoef ol sampiss and analyse* V319 g

a . '?%.•

a au a ,

AMOUNT IN PARTS PER MILLION

_____ ____ ., .. _. . .-.,n6e U4° 112° 110° IDS9": "KB*"' "" 104° . "102"9 '/ iOO°

FIGURE 21 . — Lead content of surficial materials.

AR3!1770

ILLUSTRATIONS 53

92° 90°. sa°." -"86°~ -i " "" "' " "~~ ••••-

46°

44°

42°

y D " - ——--——— ' --- —— --T- .__._ -T=TT- - - " Q

a - - . . . . : - -:-- :-. - - - ——- ~ 'B -• H. _ . . . _ . . , . - - - -—.-.—-- - -~ - i,-ga . -s Q- ". ,. .... __ .„ .,.-;.. -/ -,— ,:-..; -. . ----;_•• ,-a a -

~' D-D a a P1'*--"•-- --jj.-.U : !-:-,- -• - ..-.._:£_-•—--99 <fl a - . * - * - '".a a. . . u a " - g -• - • u " " . ._._ .,-., ..."•;..,...---.- :.s...

'a u u u __ _ LJ -_.a...._..; - .-.-"i_ .- v :^1--S"a a u

u

- ._ -3 aus u -. .B LPg / B u. .a.B B B B B a a ..._....._. ..._...

SB « o •-• ° ^B = - s e _ „•• •.... a .BBs "3 a" a -.-._ .-o_ n a A o - ' -

'= la •" . g=uB1 • B - a . . . . . "*.. a ai

=C^ °s

LJ

a, °. »= a • a1- K L,___a . = . u •-B

- a - L ' n « a a c ' S • = ,

— — B fl ^-n - .6rn B

32°

y LJ - " ~ . . _ . _ . _ . .L , ,, a LJ

- a-B- "u ^u ."

...Uu u

J u•-U.

U u - _ -

5 0 0 MILES' - - - - - - -

28°

26°

22°

94° 92° "90° " " W~~ - - 86° ""'W." -" 82* ' -- 80° . 78° . 76° _ 74°

AR3! i77

60 ELEMENT CONCENTRATIONS IN SOILS, CONTERMINOUS UNITED STATES

jna 128? 128° 124° 12T 120°. 118° 116° 114" ' 112° ifff " 108° IDS* J"D4a JQ2°•FCT—-r-j—•-—j——7——TJ———r ——r——T—— i—— "T~""' i '——i——'~i———f-

B r-t

a 'a " a a " "a" " a an " B O

-D n ;D - - a a ' - • • a. '"' 'S a a . -P a_ " . a a a . B D= = a Ba -*" a ° a B a, " a a= a a a Ba

B - - , _ B _ B u a na a a u « u a n a u a a

^LB uee • ° ' " a n B -' a u BO a u u a s aB S_"u " QaQ „ --a"-Uu " D "- a -. „ - - u ° :. -"*>r;u a u a

-a

oa • u sLt a

aca £3 " a ^ t-J LJ n

= a u s - u u.B u '.. __ . , : ao .. a _a - u a =u u a • a a B B " u BI n " B o. UB --g-P.. a a B a _.

' a u B . .a D B" BB f, a ° a "u 'nI • a a o B u u a _ a " ' " ~_—M, - B U B °a B B ua " a ~ *! au B . a o a _ a . u e o s u n

T?*, H a a Q nJt K, . _ . . .___. _. . _ •—Vi. - H

D-^D ... ^ a o a aB

a— - ' . - . - . nSYMBOLS AND PfiRCINTAGE B M° - U . ,, : - S*

OF TOTAL SAMPLES "u B a B D--a u _ _ _ Q • ' -UQ

n- rr D O^- - _ - n - - -

g a aa « = a"U- * aGeometric mean 0 MS LJ

SI

a a a •Georneinc davixion 1.52Number ol samples and analyses 1,267

BT^O LI - .

- D e

1 AMOUNT IN PARTS P£R MHXfON

2TL' ______ : ______ t ______ t

118- 115° 114° 112° 110s 108° 106° . 104° 102° 100°

FIGURE 25. — Mercury content of surficial materials.

A R 3 I 1772

78 • ELEMENT CONCENTRATIONS IN SOILS, CONTERMINOUS UNITED STATES

128°... I2g—-124° :,..1,2V.. Hfc.' "UF"".'l16r""nA? \]Z*. 110° ]Q8» 106° 102° 100* 3R

_..._"_..-____ \_U

SYMBOLS AND .PERCENTAGEOF TOTAL SAMPLES

Geornetnc mean: 0 26Geometric deviation: 2.46

lMf of samples ana analyses i .267

H8° ' 116° • 114° 112? ~ 110" 10ab 106''

FIGURE 34.—Selenium content of surficial materials.

A R 3 I 1773

ILLUSTRATIONS . 79

9T 90* 83* 86" S<" 82* 80* 78* 76° 74' 72" 70° 68° 66s 64°48°

46°

44"

42°

40°

38°

36°

34°

32°

30°

28*

26"

24*

22°

9r 90* 88" 86° 84° 82° .. 80° 78s 76° 74°

A R 3

ILLUSTRATIONS . 61

92° -90° . 88°; '"B£. . - ^ - 7 . -. , £ • - SS° . - 64°7 i \ \ I————i I r \ \ \ \ — — — ^ — — — — — -

•" '" " e:: fsT""" •

>' S

'.-V B " °. <r

5| fl W-Q ^ ^^ """ " Vi ^ _ - - •' i-V n *- f+t'f ' LJ _ . ,ta • E3 -H. i

B

' B/ Ba a

B^B n a __. ...So q-a---V- a" B a B a

n a a B n a a a

Ba 'B " ~ 8 - --=

._,,, , , ' i * m _ 5 H

8 ^Q a*

a a.

,. B « -*<'*. " ' "'>-.-•'' LJ a o

44°

42°

40°

36°

u L " "" '

34°

32°

30°

28°

26°

24°500MILES-..:—-. - " " " . --- -- -

22°' - > - t______' --' - - '

94° 92° ' 90° . * ..88° fig°'"= " 84s" '.""" 82s" ' ' 80° ' 78* '76° 74°

flR3l 1775