Nuclear Metals, Inc. Superfund Site FS Presentation · 2020. 4. 4. · FS Presentation February 12,...
Transcript of Nuclear Metals, Inc. Superfund Site FS Presentation · 2020. 4. 4. · FS Presentation February 12,...
Nuclear Metals, Inc. Superfund Site
FS Presentation
February 12, 2013
Presentation Outline
• Schedule • RI / Risk Assessment Results • FS Outline • Soil / Sediment Remedial Alternatives
• Groundwater Remedial Alternatives • Vapor Intrusion Remedial Alternatives
• Appendices
Schedule
• Provide RI Report (and EPA comments) and Risk Assessments for public review
• Provide FS Report for public review
• Prepare revised FS Report.
• EPA submits prospective remedy to NRRB (April 2013)
• EPA prepares “Proposed Plan” that identifies overall remedy
• EPA issues Proposed Plan for comment (~June 2013)
• Public Meeting on Proposed Plan (~July 2013)
• EPA issues “Record of Decision” that sets forth required remedy for Site. (September 2013)
Legend
Site Boundary
AOI Outlines
Soil Boring
Surface Soil
Sediment
de maximis, inc.
6 MACTEC N
GEOSYNTEC CONSULTANTS
•
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•
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•
A01 14 SURFACE SOILS
• •
• •
• ~ •
• •
•
Sphagnum •og,,,..
:a:
•• ••
•
•
Rl Sampling Locations Phase 1A, 18, and 1C
Nuclear Metals, Inc. Concord, Massachusetts
Remedial Investigation / Risk Assessments Results
• Extent of contamination in soil, sediment, surface water and groundwater delineated sufficiently to proceed with risk assessments.
• Surface soil and subsurface soil exceeding acceptable risk levels constrained to certain areas within Site boundary.
• Sediment exceeding acceptable risk levels constrained to portion of bog and cooling water pond.
• Groundwater contamination exceeding acceptable risk levels exists on-site and in defined area off-site.
Areas of Soil or Sediment with Unacceptable Risk
Unacceptable Risk Area
(where remediation will be evaluated in
Feasibility Study)
Distribution of MCL Exceedences for VOCs and MADEP (GW-1) Exceedances for 1,4-Dioxane in
Overburden and Bedrock Groundwater Most Recent Data through November 2009
Nuclear Metals Superfund Site Concord, Massachusetts
Areas of Groundwater with Unacceptable Risk (VOCs)
FS Outline
Section 1 –
Section 2 –
Section 3 –
Section 4 –
Introduction, background, nature and extent of contamination, risk assessment results
ARARs, RAOs, GRAs, PRGs, areas and volumes of media, ID and screening of technology types
ID and screening of technologies and process options
Detailed and comparative analysis of soil and sediment remedial alternatives
FS Outline (continued)
Section 5 – Groundwater technologies summary
Section 6 - Detailed and comparative analysis of groundwater remedial alternatives
Section 7 - Detailed and comparative analysis of vapor intrusion remedial alternatives
Excavanon Depth (ft) Fonner Acid Drain .. 1.00 Natural Gas dl 1.01-2.00 Cooling Water [] 2.01-3.00
Diverter Potable Water SupplyJFire [] 3.01-4.00 Drain Manhole Former Fire .. 4.01-6.00 Electric Manhole Sanitary .. 6.01-8.00 Floor Drain Parking Drain .. 8.01-1 0.00 Hydrant Unes Drain to Cooling Water Pond If] TB.D. by remedy selection Manhole Former storm Drain .:::1 Remove all metal &soil to Outfall Unknown AreaName Valve Site Boundary (Approx.)
~ Cooling Water Recharge Pond
CJ USTs lndustnal COurtyard Area CJ Septic Sys1em Sw'eepingsArea
Northern Pavement Drain
t:2l Trailer
Soil and Sediments Exceeding PRGs
COoling Pon d 1
/ p' (
I
"""/ Q MW-SOB
l AST-1 i
'~ • • Q MW-S23
~ -~ . :--) ---
( -----0 • _..-
---------- HA-10 . ---------______ __... 0 HA-10A ~-----_ __.v----·
.---
; t PZ-RI-002
PZ-RI-802
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sphagnum Bog
Legend 9 l.t:<'i'bilg'II'SI
+ PiexMdP;r
f:' Stm'GI;a~Q!:
() 03r>:U>,..,.,.F'Ioi,~loo::ll.,.,
o~Rel<t &, 'M1;1nao CJ~:a~rto:~VIIIt::r
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..... 13o:UI(J,o!Qef1CNIQ~edon
To1al Uranium. Most Recent 09t:acta
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. l.Ol·lO~L
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0 ~0.01-ZO!Jg'L
• ~zo.Ol!-VLI.CLEu:.....mn<einO.Oeltudon
11.Q9 10.0
,.,,
Total Uranium Concentrations_ in . Overburden Groundwater Near Holding Basm
Historical Data through May 2011 Nu::lear P.,tetaE Super1un:l SiB
Gon::ord, tv'Bl:isa.cflusetll:i
-~~~--~==~~---:~~ 25 so 100 150 200
Geosyntect> consultants
---¥-de maximJ.'s, inc.
1.4.2
Depleted Uranium in Overburden Groundwater
legerd
0 AotM:CM:Oibuld<tnCtf'Pif-1
0 B<!:dotOOkf-.. d~,..,.
Choubuden f-•Gi-~::::; t,t- OCEabo""" ~CliriOwlburJ•n !::::; 1,,..0io~neab-~AOI!P"Otlrlkr, V.•rGuldlh lnO....!Ourd•n
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~Wiil02 0\erburden~onit>ri-o.il"""ll
VOC and 1,4 .. Dioxane Plume Areas in Overbu rden a nd Bed roc k Groundwater
MOst Recent Data through 2011
Nu:lear Nletals Su~rfund Site rvb.ssachusetts
Figure
1.4.3
VOCs and 1,4-dioxane in Overburden and Bedrock Groundwater
0 50 100 200
Uranium Conoentretlon!lln Bedrock Groundwoter
Historiool Dolo thr<XJgh May 2011 Nuclear Metals Superfund S~e
Concord, Massachusetts
Uranium in Bedrock Groundwater
+ Piezometer
• StaffGaupe
• ActiVe Overburden Suppty Wen
• Former Overburden Supply Well
• Former Bedrock Suppty WeH
PublicWatM ~ 'lllell
'Netlands
SurlaceV'IAiter
RivO<
SepticAetds
Si~ Boundaty
D .,.,"" ~s Exceeding Vapor Intrusion Screening Levels
Chloroform· 0.71 ~
VC · 0.14 1J~
VOC. detected in overburden 101 at concentrations geatef than anatytical reporting limits
"" "" ...,
Areas Exceeding Vapor Intrusion Screening Levels
Nuclear Metals Superfund Site Concord, Massachusetts
Figure
1.4.5
Potential Vapor Intrusion Areas
FS “nuances”
• Extensive use of tables – review needs to incorporate tables in concert with text
• Rather than go through detailed analysis for each media, then comparative analysis, this FS presents detailed and comparative analysis for soils / sediment, then groundwater, then vapor intrusion.
• Alternatives for soil remediation limited to excavation and containment (either on-site or off-site). Saturated soils acting as source material evaluated in soils alternatives.
• Groundwater alternatives address overburden DU plume, overburden / bedrock VOCs and 1,4-dioxane, and bedrock U plumes separately.
FS “nuances” (continued) • “Green” remediation considered in detailed and
comparative analysis.
• Costs for RD Work Plan and POP, which will detail predesign investigations and design process for all media, are carried in only the soil and sediment alternative costs,
• Costs associated with ICs are carried in only the Groundwater – VOC and 1,4-dioxane alternatives. Costs incorporate the potential ICs applicable to all media. Higher costs expected to obtain off-property easements that would be needed to implement hydraulic containment and treatment are carried in that alternative,
• Costs associated with performing five-year reviews are carried in the Groundwater – Depleted Uranium alternatives.
Soil and Sediment Remedial Alternatives
• SS-1
• SS-2
• SS-3
• SS-4
No Action
Excavation, Stabilization of Saturated Soils within Holding Basin, On-Site Containment, and Site Restoration
Excavation, Containment of Holding Basin, Some On-Site/Most Off-Site Disposal, and Site Restoration
Excavation, Containment of Holding Basin, All Off-Site Disposal, and Site Restoration
Note on Soils / Sediments Remedial Alternatives with Respect to Holding Basin
Excavation of all impacted soils below and immediately downgradient of the Holding Basin (down to bedrock) was considered in the development and screening of technologies (Section 3.1.4) portion of the FS.
Conceptually, this would be a 90’ deep hole, removing ~95,000 cy, requiring extensive shoring, dewatering, and water treatment. This aspect of the remedy alone would be > $110,000,000.
The expected technical difficulties and costs associated with this approach are grossly disproportionate to the effectiveness, so it was screened out of further evaluation.
650 600
LEGEND
D·.-. .J9~:" Gc«ompo-..iiC
60 tnl HO~ET~'( !Ml11 (l<gt~!•b 1''" Geosyf\tttl< Ci) .f'IE((J(2-t•clt~
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6"' G.:.s 'h'l:irqA~.)tt
550 500 450
Zone 1 -Uranium> 30 mg/kg in Vadnose Zone Soils Zone 2 - Uranium >30 mg/kg in Saturated Zone Soils Building to be demolished
Distance units depicted are feet (ft)
Stratified Drift
400 350 300 250
12~ S.nd Sed~ Prim.ll)' C~K'OO C~O«;MOOS1!~
(rtK("COII8ilb'l~tli· ~rtcrA:I'd._.Df>Fin5 .. 01'o6•F-~IIg~!l')
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- 20
- 0.0
--20
- -40
- -60
200 150 100 80 0
SS2 -Containment Facility Elevation View Feasibility Study
Nuclear Metals Superfund Site
Name: Fig4.3.2_CF _profile Date 1113012012 Author. HGaedy Project No.: 3215 Reviewed by: VR
SS – 2 Excavation, Stabilization of Saturated Soils within Holding Basin, On-Site Containment, and Site Restoration
SS – 2 Excavation, Stabilization of Saturated Soils within Holding Basin, On-Site Containment, and Site Restoration
• Excavate and place approximately 77,000 cy of site soils and sediments into an on-site containment facility;
• Holding Basin – Excavate and place unsaturated zone within
containment facility
– Stabilize in-situ saturated soils within the Holding Basin footprint;
• Construct on-site containment facility; and • Restore site Costs: Capital: $35,880,000 O&M (NPV, 200 years, 7%): $ 7,465,000 Total: $43,345,000
• --m
SS3. Vertical Barrier Walland Cap Feasibility Study
Nud(tiY Mc.-tt1.s SUporfl.l'ld S.to
Zone 1 • Uranium > 30 mglkg in Vadnose Zone Soils Zone 2 - Uranium > 30 mgl kg in Saturated Zone Soils Zone 3 - Uranium > 30 ug/1 in Groundwater Building to be demolished
125" Asphtt.th Su1¥.e 1\ ~ Ao;ph.lu!l [l._o;p
S"A<J9"'1•"''-'>.,
30.75." (0\ler Fill {StatiC 8a'T!er)
~>'•Hid'~~ G::u.UH!I.IO\dC
60 m l HOP::l<!xturcc &~'T!br.:M
(";1"'\")'(.}'f'l!hNi<(l.ly l !fiC'te'l'}.i"("L'Y
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- 20
-00
- -20
- -60
-00
-100
SS3 - Vertical Barrier Wall Elevation View Feasibil ity Study
Nuclear Metals Superfund Site
Name: F ig4.3.4_HB_proflle Date: 11130/2012 Author. HGaedy PrOJect No: 3215 Rev~dby: VR
SS – 3 Excavation, Containment of Holding Basin, Some On-Site/Most Off-Site Disposal, and Site Restoration
SS – 3 Excavation, Containment of Holding Basin, Some On-Site/Most Off-Site Disposal, and Site Restoration
• Excavate approximately 77,000 cy of site soils and sediments;
• Dispose off-site most soils and sediments; • Holding Basin
– Placement of ~8,500 cy of least impacted site soils to bring the Holding Basin up to grade
– Install containment wall – Install impermeable cap over walled area; and
• Restore site. Costs: Capital: $56,927,000 O&M (NPV, 200 years, 7%): $ 4,506,000 Total: $61,433,000
Bldg· C r .. ···········-······: ~--------·- .
Stratified Drift
Zone 1 • Uranium > 30 mglkg in Vadnose Zone Soils Zone 2 - Uranium > 30 mgl kg in Saturated Zone Soils Zone 3 - Uranium > 30 ug/1 in Groundwater Building to be demolished
125" Asphtt.th Su1¥.e 1\ ~ Ao;ph.lu!l [l._o;p
S"A<J9"'1•"''-'>.,
30.75." (0\ler Fill {StatiC 8a'T!er)
~>'•Hid'~~ G::u.UH!I.IO\dC
60 m l HOP::l<!xturcc &~'T!br.:M
(";1"'\")'(.}'f'l!hNi<(l.ly l !fiC'te'l'}.i"("L'Y
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6"G.'t\~111'1)1\!j1Jr(l(l.ltC'
SS3 - Vertical Barrier Wall Elevation View
Name: F ig4.3.4_HB_proflle Date: 11130/2012
SS – 4 Excavation, Containment of Holding Basin, All Off-Site Disposal, and Site Restoration
SS – 4 Excavation, Containment of Holding Basin, All Off-Site Disposal, and Site Restoration
• Excavate approximately 77,000 cy of site soils and sediments;
• Dispose off-site all soils and sediments; • Holding Basin
– Use clean off-site soils to bring to grade – Install containment wall – Install impermeable cap over walled area; and
• Restore site. Costs: Capital: $62,413,000 O&M (NPV, 200 years, 7%): $ 4,506,000 Total: $66,919,000
Groundwater Remedial Alternatives DU in overburden: • DU-1 No Action • DU-2 Source Isolation (SS-2, -3, or -4) with Hydraulic
Containment and Ex-situ Treatment
• DU-3 Source Isolation (SS-2, -3 or -4) with In-Situ Treatment
VOCs and 1,4-dioxane in overburden and bedrock: • VOC-1 No Action • VOC-2 Hydraulic Containment with Ex-situ Treatment
• VOC-3 Monitored Natural Attenuation / Long-term monitoring
Uranium in bedrock: • UROCK-1 No Action • UROCK-2 Hydraulic Containment with Ex-situ Treatment
• UROCK-3 Long-term Monitoring
Source Area Vertical Containment Barrier
Holding Basin Cap
Legend
~ Proposed Pumping Well .., Proposed Mon~oring Well
~ Monitoring Well
... Piezometer
• Former Bedrock Supply Well
---· Uranium MCL Exeeec!anee (>30 ~giL)
0 sae Boundary
N
~ A
1m Source Area Vertical Containment Barrier and Cap
- Estimated Hydraui c Capture Zone (Note 1)
___.. Groundwater Hydraulic Gradient
Notn I Thttlt.lwMedU~P 110ne M~'!.ane•ncaonQ::t"ol apptllliiNtety 18 gpm, b~ed on a hydtalulc: orNtnl 010 011.;) "rd'~C CDt\OJdMt'f ot 31 Wdav • .a~""""**" of 115 t anct a p1....,.. rf'Kble$6. ot 42ft 7 ftr k:Jcdflons ol COtM'ya"'Ct ptpng. lnl~ftl bu4dlng itftd lhthargt llnr co be dtctm'Wied Oumo tf"f'NOI~ d~')n 3 SoutH 1D.It10n ~nc._.drtt t-lo.,•ng 8-H•n Cap and Vetlltal8.arntr
DU-2: Source Isolation with Hydraulic Containment
for Depleted Uranium in Overburden
DU-2 Source Isolation (SS-3/4 shown) with Hydraulic Containment and Ex-situ Treatment
DU-2 Source Isolation with Hydraulic Containment and Ex-situ Treatment
Institutional Controls to prohibit future use of impacted groundwater.
Hydraulic Containment and Ex-situ Treatment - groundwater extraction and treatment to hydraulically capture groundwater containing DU (>MCL) and ex-situ treatment of the extracted groundwater to remove metals and organic compounds, and discharge of the treated effluent to the Assabet River.
Long-term monitoring of groundwater elevations to confirm hydraulic capture, monitoring of groundwater quality to assess concentration decreases and monitoring of system influent and effluent to meet permit requirements.
DU-2 Source Isolation with Hydraulic Containment and Ex-situ Treatment
Pore Space Area / Volume = 0.92 acres / 253,000 ft3
DU Mass addressed = 6.0 kg
Costs:
Capital: $ 923,000 O&M (NPV, 200 years, 7%): $ 9,086,000 Total: $10,009,000
Source Area Vertical Containment Barrier
MW·S18
Holding Basin Cap
Legend
Proposed Reactive Zone Monitoring Well
e Proposed Media Injection Point (Apatite)
~ Monitoring Well
+ Piezometer
e Former Bedrock Supply Well
Uranium MCL Exceedance (>30 ~giL)
c::J Site Boundary
~Source Area Vertical Containment Barrier and Cap
___. Groundwater Hydraulic Gradient
Notes Source Isolation Includes Holding Basin Cap ana Vertical Barrier
Reactive Zone 1 (RZ-1) 3D Apatite Based Media Inj ection Points at 25 n: radii spacing to minimize occlusion due to proximity to source zone
Reactive zone 2 (RZ-2) 30 Apatite Based Media Inj ection Points at 14 tt radii spacing to capture remaining mass nux from RZ-1
Reactive Zone 3 (RZ-3) 30Apatlte Based Media Injection Points at 7 rt radii spacing to act as secondary containment for residual uranium not capbJred in RZ-1 and RZ-2.
DU-3A: Source Isolation and In-Situ Treatment with Apatite
for Depleted Uranium in Overburden Nuclear Metals Superfund Site
Concord Massachusetts
10 11o--•sll[o===-----~1 0~881
------¥-de maximis, inc.
DU-3aSource Isolation (SS-3/4 shown) with In-Situ Treatment
rtf P.W-7A
HA<l
Source Area Vertical Containment Barrier
MW-518
Holding Basin Cap
Legend
<9 Proposed Reactive Zone Monitoring Well
e Proposed Media Injection Point (Apatite)
0 Proposed Media Injection Point (Zero Valent Iron (ZVI))
~ Monitoring Well
-+ Piezometer
• Former Bedrock Supply Well
---· Uranium MCL Exceedance (>30 ~giL)
c:J Site Boundary
1m Source Area Vertical Containment Barrier and Cap
____.. Groundwater Hydraulic Gradient
Notes· Source Isolation includes H aiding Basin Cap and Vertical Barri er
Reactive Zone 1 (RZ- 1): 30 Apatite Based Media InJeCtion Points at 25 n radii spacing to minimize occlusion due to proximity to source zone
Reactive Zone 2 (RZ-2): 30 A patite Based Media Injection Points at 14 n radii spacing to capture remaining mass nux from RZ-1
Reactive Z one 3 (RZ-3) 30 ZVl lnjection Points at 7ft radii spacing to act as secondary containment fa· residual uranium not captured in RZ-1 and RZ-2. ZVI occlusion not anticipated at
I due to i I in RZ-1 and RZ-2
Treatment with Apatite and ZVI for Depleted Uranium in Overburden
Nuclear Metals Superfund Site Concord, Massachusetts
1 0."o--•sll[o===~-----~10~eet
----¥-de maximis, inc.
DU-3b - Source Isolation (SS-3/4 shown) with In-Situ Treatment
DU-3 - Source Isolation with In-Situ Treatment
Institutional Controls to prohibit future use of impacted groundwater.
In-Situ Treatment via apatite and/or zero valent iron permeable reactive barriers (PRBs). This remedy component results in sequestering uranium both in sorbed and mineral precipitate forms. Pilot testing would be conducted during remedial design to select reagent.
Long-term monitoring of groundwater quality to assess concentration decreases due to dispersion, dilution and volatilization (MNA).
DU-3 - Source Isolation with In-Situ Treatment
Costs Capital: $1,263,000 O&M (NPV, 200 years, 7%): $2,933,000 Total: $4,196,000
Costs are for DU-3a – the slightly more expensive of the two approaches
Pl'l)0(1!::>8d f!xllacbOn W&U in 8eCSrock
Pr(lpOstd Eli:lrAetiOI\ Wttlln 0Ytl'bUrd4fl
8 Mon•1onn9 Wtll
P18lOM919r
- ErotJmat9d Hvdr;tuhcCaPtuf'9 Zono lor Extroctton Woll•n 8Gdrock
Eshmeted H~dl'\\uhe Captu,. Zont tor F.lCtr•chOn weu 10 Overburden
~~~~ ' . .. !"'
" ""m ~~ .. ~r:.t •
\ \
\
., -.
L :I 1. 1- OCE &bove MCI. 1n Ove!'bufden
L : l 1,4·0toxan• ebov~ MAOEP Onnking Wattr GUidehnt in O~trburdtn
0 t.4~Diorani' above MAOEP Dnnk•na Wat•r Gutef&hl"'t •n 8tdrork
L_ :I PCE above MCL '" Overt>u~d&n L. :I TCE obovo MCLin Ovorb<irdon
0 TCE above MClin Sidi'O¢k
~ WiH8nds
Smftlct Water
D Stft 80Uf'ldiry
"*~ to~ Ovortturnen MonJonno weu
t~W.U$01 U&drock Mon1tonno Well MW· IO Non 1\JtiG!Iontll Monttonng Well
~tly<1r'.lUIIC graGtntorO OU • .)I'IyQfAfiC (Of'IOXWCVOI' • 3nl01f. apunewlcttnot200 rtal'lltaplumt D"III:Wis ct50 n OflatfjarauiJC Qf~l!f'l(of0004.~ cooouctMcyot 02)ft/OJy. aptl.lmt W!OO'!Of4JOR•no 1 pUnt u.:t<tten(f(z.51t.
N
i VOC-2: Hydraulic Containment for
VOCs and 1,4-Dioxane in Overburden and Bedrock
Nuclear Metals Superfund Site Concord, Massachusetts
20~0 .... ~,0;0====~ ......... 2~~·~
2-dt ma.ximlr, 111c.
VOC-2 Hydraulic Containment with Ex-situ Treatment
VOC-2 Hydraulic Containment and Ex-situ Treatment
Institutional Controls to prohibit future use of impacted groundwater.
Hydraulic Containment and Ex-situ Treatment - one groundwater extraction well in deep overburden and two groundwater extraction wells in bedrock in the area between Main Street and the Assabet River and ex-situ groundwater treatment building to treat 1,4-dioxane (e.g. advanced oxidation), then discharge the treated water to surface water.
Long Term Monitoring of groundwater elevations to confirm hydraulic capture, monitoring of groundwater quality to assess concentration decreases due to dispersion, dilution and volatilization (MNA) and monitoring of system influent and effluent to meet permit requirements.
VOC-2 Hydraulic Containment and Ex-situ Treatment
Pore Space Area / Volume = 12.39 acres / 10,034,000 ft3
(area is for 1,4-dioxane overburden, volume includes bedrock)
VOC mass addressed = 2.11 kg 1,4-dioxane mass addressed = 3.41 kg
Assumed time to clean up (off-property) = 30 years
Costs: Capital: $4,386,000 O&M (NPV, 30 years, 7%): $4,291,000 Total: $8,677,000
VOC-3 MNA/Long-term Monitoring
Institutional Controls to prohibit future use of impacted groundwater.
Long Term Monitoring for VOCs and 1,4-dioxane to evaluate concentration decreases due to biodegradation, dispersion, dilution and volatilization (MNA).
Assumed time to clean up (off-property) = 30 years
Costs: Capital: $ 904,000 O&M (NPV, 30 years, 7%): $ 811,000 Total: $1,715,000
Legend Wellin Roc~ osod Exvocuon "'I Prw
~ Mot11tonng W~l emratlons (IJg/L) 2011 Uranium Cone May
• 003 I 00
• 1 01· 10 00
0 1001 -3000
• 30 01-100000
• 100001 600000 tZono(Note1) Hy
orauhc Gapcur (~ NGVD) - Esameteo Eltvlllon Contour NGVD)
2008 Grounclwtttr atlon Contour (h 123- Apnl Grounclwot•r Eltv I 2008 Esamotoo rt<lotnt
123- • Apn .,...,., hydr•M g CL o1 ~0 ~ ----+ A~>t" 2008 Groun .,~m tx(tfeb •n• M
ADPtoxwn•• •n Yw1liti tlf
c:J RM>r
D S!IoBounelaly • .-"'""'""'""'=~•• CW.4llUli'I.IM ot ~~ ~a;..., ..... '":"'"'~ .,....,.~~ • .;..»at ~~•-go 1n0 lObe 15 •·:!:!..':ne~17&"-:_:t:.erct1Ut,;ng NI:Jay,ap. GICOfMYW'Ce • -----:-:-;::::;~t 2r ........................ _ _ • ent ....,_ .... "~~ . Contamm
UROCK-2: Hydrau:~c Bedrock for Uranium s perfund Site
Nuclear M~ta~as~achusetts Concor_. ____ _
UROCK-2 Hydraulic Containment and Ex-situ Treatment
UROCK-2 Hydraulic Containment and Ex-situ Treatment
Institutional Controls to prohibit future use of impacted groundwater.
Hydraulic Containment and Ex-situ Treatment - includes installation of one groundwater extraction well in shallow bedrock at the downgradient end of the isotopically natural uranium plume (near MW-BS28), construction of a treatment system to remove uranium from extracted groundwater, and discharge of the treated water to surface water.
Long-term Monitoring of groundwater elevations to confirm hydraulic capture of the uranium plume in bedrock groundwater, monitoring of groundwater quality to assess uranium concentration trends, and monitoring of system influent and effluent to meet permit requirements.
UROCK-2 Hydraulic Containment and Ex-situ Treatment
Pore Space Area / Volume = 7.99 acres / 233,600 ft3
Uranium mass addressed: 0.57 kg
Costs: Capital: $1,163,000 O&M (NPV, 200 years, 7%): $6,387,000 Total: $7,550,000
UROCK-3 Monitoring
Institutional Controls to prohibit future use of impacted groundwater.
Long Term Monitoring for uranium to evaluate concentration decreases due to dispersion, dilution, and precipitation.
Costs: Capital: $ 904,000 O&M (NPV, 200 years, 7%): $ 811,000 Total: $1,715,000
Vapor Intrusion Remedial Alternatives
VI-1 No Action
VI-2 Institutional Controls and Development Restrictions
VI-3 Institutional Controls and Vapor Mitigation
VI-2 Institutional Controls and Development Restrictions
Institutional Controls would be implemented to limit construction of new buildings to areas where significant VI is not expected.
Costs: Capital: $ O&M (NPV, 30 years, 7%): $136,000 Total: $136,000
VI-3 Institutional Controls, Future Investigation and Vapor Mitigation (if needed)
Institutional Controls would be implemented to require that new buildings include vapor mitigation measures in areas where unacceptable VI is possible.
Future Investigation includes new monitoring wells and soil sampling.
Vapor Mitigation would include vapor barrier plus sub-slab venting system – costs assume 10 future residential buildings, each with a 1,600 ft2 footprint
Costs: Capital: $ 459,000 O&M (NPV, 30 years, 7%): $ 918,000 Total: $1,377,000
Note on Costs
FS costs calculated pursuant to EPA’s guidance, which requires use of 7% discount rate for net present worth analysis of longterm O&M costs.
Using current Whitehouse OMB discount rate1 of 1.1% increases O&M costs by factor of ~5.9 (i.e., an O&M cost estimated in the FS using 7% discount of $10 million would actually cost $59 million to fund using today’s interest rates)
1 http://www.whitehouse.gov/omb/circulars_a094/a94_appx-c.
Noteworthy FS Appendices Appendix B – PRG calculations
Appendices C, D & E – Soil, Groundwater and VI Cost Estimates
Appendix H – TEDE Evaluations (ResRad & Dose Compliance Calculator)
Appendix I – Institutional Controls Analysis