U.S. EPA J. F. Kennedy Building Boston, MA 02203 · U.S. EPA J. F. Kennedy Building HSN-CAN 5...
60
LETTER OF TRAN DATE: May 3,1991 TO: Richard Goehlert U.S. EPA J. F. Kennedy Building HSN-CAN 5 Boston, MA 02203 RE: Savage Well Site SUBJECT: Final RI Revisions For Your Information Per Your Request FROM: Mark O. Heuberger HMM Associates, Inc. 196 Baker Avenue Concord, MA 01742 JOB NO.: 2176-150 For Your Review/Comments For Your Authorization REMARKS: Enclosed are the final RI revisions, completed in accordance with your letters of 3/12/91, 3/14/91, and 3/25/91. Per your request, we are submitting at this time only those pages which have been revised. The changes have been noted in the text and keyed to the numbered RI comments. Following your review and approval of this revisions, a final revised draft of the RI will be submitted. The changes made in this version of the Remedial Investigations Report have been made at EPA's specific direction which was, in EPA's words, "non-negotiable." As required, the EPA's directed changes have been made verbatim. As such these statements are not made by the PRP or their consultants, and should not be construed in any context as admissions of the PRP or their experts. Moreover, the PRP Group objects to many of the required revisions and, as EPA has recognized, as is appropriate in such cases, the Group will submit more specific objections to EPA's mandated revisions in a separate letter, which we understand will also be a part of the administrative record. d> Signature COMMENTS: / . /Date Signature Date 2176-150/HAZ/5178 - 5/3/91
Transcript of U.S. EPA J. F. Kennedy Building Boston, MA 02203 · U.S. EPA J. F. Kennedy Building HSN-CAN 5...
LETTER OF TRAN
DATE: May 3,1991
TO: Richard GoehlertU.S. EPAJ. F. Kennedy BuildingHSN-CAN 5Boston, MA 02203
RE: Savage Well Site
SUBJECT: Final RI Revisions
For Your InformationPer Your Request
FROM: Mark O. HeubergerHMM Associates, Inc.196 Baker AvenueConcord, MA 01742
JOB NO.: 2176-150
For Your Review/CommentsFor Your Authorization
REMARKS:
Enclosed are the final RI revisions, completed in accordance with your letters of 3/12/91,3/14/91, and 3/25/91. Per your request, we are submitting at this time only those pages whichhave been revised. The changes have been noted in the text and keyed to the numbered RIcomments. Following your review and approval of this revisions, a final revised draft of the RIwill be submitted.
The changes made in this version of the Remedial Investigations Report have been made atEPA's specific direction which was, in EPA's words, "non-negotiable." As required, the EPA'sdirected changes have been made verbatim. As such these statements are not made by the PRPor their consultants, and should not be construed in any context as admissions of the PRP or theirexperts. Moreover, the PRP Group objects to many of the required revisions and, as EPA hasrecognized, as is appropriate in such cases, the Group will submit more specific objections toEPA's mandated revisions in a separate letter, which we understand will also be a part of theadministrative record.
d>
Signature
COMMENTS:
/./Date
Signature Date
2176-150/HAZ/5178 - 5/3/91
Hampshire Division of Public Health Services initiated investigations into the potential sources
of the contaminants. Inspection of the four major industrial facilities, (OK Tool, Hitchiner,
Hendrix, and NESFAB) and of several of the smaller commercial establishments in the area was
conducted to assess the prevailing waste management practices and the potential impacts on
groundwater quajity (see following section). Subsequently, hydrogeologic investigations were
initiated at the OK Tool Company and the Hitchiner Manufacturing Company by privately
retained consultants. In the summer and fall of 1984, NHWSPCC implemented a
hydrogeological study of the area.
The Savage Well site was placed on the National Priority List (NPL) of hazardous waste
sites in September, 1984 under the provisions of CERCLA. The site was included on the NPL
primarily because of the detection of contamination in the Savage Well which had been used as
a public water supply prior to February, 1983. (^^
A group of local industries, consisting of OK Tool Company, Hitchiner Manufacturing
Company, Hendrix Wire and Cable, and New England Steel Fabricators, were identified by EPA
as Potentially Responsible Parties (PRPs). Under the provisions of CERCLA and SARA, the
PRP Group agreed to investigate the nature and extent of the contamination detected in the
Savage Well. In accordance with a consent decree signed by the PRP Group and EPA and
effective 8/10/87, the PRP Group agreed to conduct a remedial investigation/feasibility study
prepared by EPA Region I. HMM Associates, Inc. was retained by the PRP Group as a
consultant to aid them in completing the RI/FS. A Project Operations Plan (POP) was prepared
by HMM Associates, Inc., approved by the EPA, and serves as the guideline for site
characterization activities performed during the RI.
1.2.3 Previous Investigations
Previous investigations within the study area include work performed by Normandeau
Associates, Inc. to investigate the OK Tool Property, work performed by Roy F. Weston, Inc. to
investigate the Hitchiner Property, work performed by Normandeau Associates, Inc. to
investigate the New England Steel Fabricators property, and a hydrogeological investigation of
the study area performed by the New Hampshire Water Supply and Pollution Control
Commission. The following is a partial list of existing reports on previous investigations
relative to the study area:
2176-150/HAZ/5146 1-8
TABLE 1-2
CHEMICAL USAGE FOR HTTCHINER.
HENDRIX. O.K. TOOL AND NESFAB
HTTCHINER
Chemical/Name *
1,1,1 Trichloroe thaneChloroethene UG (trade name)
ApproximateDates Purchased
1972 (June thruDecember)
197319741975197619771978197919801981198219831984198519861987198819891990 (to about
September)
Tetrachloroethene* ,2
Isopropyl Alcohol
Acetone
Sodium Hydroxide
Acids
Oil
Deoxidine 670(acid/base steel brightener)
Methyl Isobutyl Ketone
12/18/81,04/23/82,07/08/83
1962 (estimate topresent)
1962 (estimate topresent)
1955 (estimate topresent)
1952 (estimate topresent)
1952 (estimate topresent)
1980-84 (estimate)
1982
AmountPurchased
84 (in 55-gallon drums)
21621018825621926020418317214821423659184110181111140
(in 55-(in 55-(in 55-(in 55-(in 55-(in 55-(in 55-(in 55-(in 55-(in 55-(in 55-(in 55-(in 55-(in 55-(in 55-(in55-(in 55-(in 55-
gallon drums)gallon drums)gallon drums)gallon drums)gallon drums)gallon drums)gallon drums)gallon drums)gallon drums)gallon drums)gallon drums)gallon drums)gallon drums)gallon drums)gallon drums)gallon drums)gallon drums)gallon drums)
1.3 (in 55-gallon drums)
12 55-gallondrums/month
5 Gallon cans onanas-neededbasis
45-50 55-gallonDrums/month
N/A
N/A
2-3 55-gallonDrums/year
1 55-gallonDrum
A small amount of product PCE was used in Hitchiner's research laboratory. PCE was not used in themanufacturing process.
2176-150/HAZ/5146 1-15
CHEMICAL USAGE FOR HTTCHINER.
HENDRDC. O.K. TOOL AND NESFAB
HENDRTX
acetepbenone^ Estimated usage dates N/Amethytene chloride2 1960 to present N/Axylene2 " small quantities2
methyl styrene^
Year Purchases of Gallons
1,1,1 trichloroethane4 1974 551975 2201976 2751977 551978 01979 551980 551981 2171982 2201983 1651984 4401985 2751986 4951987 6051988 3851989 4401990 165Total 4,122
O.K. TOOL
Year
Tetrachlorethylene8 1977 6601978 23811979 2,1501980 1,4591981 1,1551982 5051983 7291984 2161985 83
(returned)1986-1988 N/A
1983 330Anderson Oil Lusol 96 1984 495
1985 165
2176-150/HAZ-5146 l-15b
TABLE 1-2 (Cont'd^CHEMICAL USAGE FOR HTTCMNER.HENDRIX. O.K. TOOL AND NESFAB
OKTOOL(Cont'd)
Amount. Bttshiwl
Chemical/Name1 Year (gallona)
Freon TF Solvent 1985 20Rando AD46 1983 660
1984 7701985 8801986 4951987 110
Way lube 11 80 68 1983 1101985 551986 55
MobilnetS-122 1984 51985 5
WB Grinding Oil 2840 1983 5181984 10061985 5081986 522
Protection Oil 1983 55Formula L Coolant 1986 5 ^\No-Carb 1983 8 (JjJ
1984 8Habcool3l8 1983 4
1984 4Prime Cleaner 1985 5
tnchloroetbylene (TCE)2 early 1940's- 1984 N/A1,1,1 trichloroethane (TCA) " N/Amethylene chloride " not regularly used*chloroform " not regularly used2
cutting oils^ " N/Apaints" " N/Acaustic oxidizing agents-' " N/A
Cadillac Paint & Varnish Co., Inc. Estimated usage dates N/ATN-4 lacquer thinner6 - 1 960 to present
paint6 " N/A1,1,1-TricUoroethanelChesterton 1977 220 gallons'
No. 261 Safety "^ 1978 385 gallons1979 550 gallons1980 440 gallons1981 660 gallons1982 440 gallons1983 55 gallons.1984 110 gallons9
1985-1990 N/AMineral Spirits 1984 1,639 gallons
1985 1,232 gallons1986 671 gallons1987 N/A1988 1,287 gallons
1989-1990 N/A
2176-150/HAZ-5146 l-16a
TABLE 1-2 (Cont'd)
USAGE FOR HTTCHINER.
HENDRTX. O.K. TOOL AND NESFAB
Chemical/Name1
N-Butanol
N-Butyl Acetate
MIBK
Toluene
Isopropanol
Xylol
Ethyl Acetate
MEK
Zinc Chr ornate
Linseed Oil
Year
t£ESEAfi(Cont'd)
1984198519861987
1988-19901984198519861987
1988-19901984198519861987
1988-199019841985198619871988198919901984198519861987
1988-190198419851986
1987-1990198419851986
1987-19901984198519861987198819891990198419851986
1987-1990198419851986
1987-1990
AmountPurchased(gallons)
34 gallons23 gallons30 gallons31 gallons
N/A145 gallons101 gallons26 gallons12 gallons
N/A135 gallons103 gallons16 gallons10 gallons
N/A695 gallons483 gallons631 gallons648 gallons605 gallons715 gallons440 gallons110 gallons77 gallons99 gallons105 gallons
N/A7 gallons
N/A7 gallons
N/A4 gallons
N/A5 gallons
N/A15 gallons55 gallons282 gallons
N/A330 gallons715 gallons440 gallons594 gallons
N/A704 gallons
N/A396 gallons
N/A468 gallons
N/A
2176-150/HAZ-5146 l-16b
TABLE 1-2 (Coat'd)
USAGE FOR HTTCHINER.
HENDRDC. O.K. TOOL AND NESFAB
AmountPurchased
Chemical/Name L Year (gallons)
MESEAB(Cont'd)
QIHER
Lithum Silicate+ Maleic Anhydride+ Carbon Tetracfaloride+ l-Methoxy-2-Propanol Acetate+ Toluene Di-Isocyanate Polymer+ Free Isocyanate Monomer+ Titanium Dioxide+ n-Heptane+ Diethylamine+ 2-Ethoxyethyl Acetate+ Dipbenylmethane Diisocyanate Polymer+ Dipbenylmethane Diisocyanate Monomer+ Lead+ Cadmium
Zinc OxideZinc Dust
+ Ethanol+ < 10 gallons per year
N/A Information not available1 Letter from legal counsel for Hitchiner Manufacturing to HMM Associates, Inc., 1/28/912 Hydrogeological investigation of the Savage Well Site, Milford, NH, June, 1985
Hydrogeological Investigation Unit, NHWSPCC3 From 1983 RCRA Inspection Report4 Letter from legal counsel for Hendrix to HMM Associates, Inc., 11/26/905 General Safety Plan for OX.. Tool Company, Inc., Route 101, Milford, NH
Hydrogeologic study and contamination source evaluation program, Normandeau Associatesjnc.,August, 1983
6 3-16-85 Laboratory Analytical Sheet, Stevens Water Analysis, 1983, Montvale Ave., Stoneham, MA7 Letter from legal counsel for NESFAB to Ms. Sharon Y. Ergeau, NH DES Bureau of Hazardous Waste
Management, September 28, 19838 Letter from legal counsel for O.K. Tool to HMM Associates, 2/5/91.9 Letter from legal counsel for NESFAB to HMM Associates, 1/31/91
2176- 150/HAZ-5146 l-16c
TABLE 2-5
SUMMARY OF GROUNDWATER MONITORING WELLSSAVAGE WELL SITE
Well Number
MW-1AMW-1BMW-1C
MW-2AMW-2BMW-2R
MW-3
MW-4AMW-4BMW-4R
MW-5AMW-5B
MW-6AMW-6B
MW-7AMW-7B
MW-8AMW-8B
MW-9AMW-9BMW-9C
MW-10AMW-10BMW-10C
MW-11AMW-11BMW-11R
MW-12AMW-12B
MW-13AMW-13B
MW-14AMW-14BMW-14R
MeasuringPoint
Elevation-^
281.62281.62281.42
269.32269.19268.95
270.59
268.43268.73268.25
269.82269.69
269.04269.08
264.30264.26
263.87263.77
267.96267.84268.23
264.33264.51264.87
262.84262.88263.21
265.91266.06
259.78259.50
254.72255.00255.62
1 Top of Outer Steel Casing -2176-150/HAZ/5146
LandSurface
Elevation
±279.51±278.66±279.74
±266.49±266.25±266.75
±268.65
±266.46±266.94±266.94
(±267.69)(±267.56)
±266.96±267.02
±262.05±262.26
±261.87±261.65
±265.94±265.94±266.12
±261.93±260.79±262.06
±260.83±260.72±261.21
±263.56±264.25
±257.67±257.80
±253.26±253.40±253.62
Cap Removed.
ScreenedInternal
Elevation
274.51-262.51244.16-234.16228.74-218.74
237.49-227.49195.25-185.25132.75-102.75
257.15-247.15
246.96-236.96220.94-210.94204.25-170.25 '
228.87-218.87215.16-205.16
261.04-249.04210.52-200.52
259.05-249.05216.76-206.76
253.87-241.87204.65-194.65
235.44-225.44207.94-197.94186.12-176.12
242.93-232.93216.79-206.79180.56-170.56
240.33-230.33208.72-196.72191.21-160.71
238.56-228.56208.25-198.25
233.67-223.67209.3-199.30
234.26-224.26203.40-193.40180.62-143.62
(D2-26
ScreenedInterval/Depth
5-1735.5-45.5
51-61
29-3971-81
134-164
11.5-21.5
19.5-29.545-5664-98
28.0-38.050.5-60.5
8-2056.5-66.5
3-1345.5-55.5
8-2056.5-66.5
30.5-40.558-6880-90
19-2944-54
81.5-91.5
20.5-30.552-64
70-100.5
25-3556-66
24-3448.5-58.5
19-2950-60
73-110
ScreenedMaterial
Sand and gravelGravely sandF. sand
Sand and gravelSand and gravelBedrock
Sand and gravel
Sand and gravelWeathered bedrockBedrock
Sand and gravelSand and gravel
Sand and gravelSand and gravel
Gravelly sandSand
Gravel and sandGravelly, silty sand
Sand and gravelSandGravelly, silty sand
Sand and gravelSandSand
Gravelly sandSilty sandBedrock
SandSand
Gravelly sandSand
Gravelly sandGravelly sandBedrock
TABLE 2-5 (Cont'd)
SUMMARY OF GROUNDWATER MONITORING WELLSSAVAGE WELL SITE
Well Number
MW-15AMW-15B
MW-16AMW-16BMW-16C
MW-17AMW-17BMW-17C
MW-18A
MW-18B
MW-19AMW-19B
MW-20AMW-20B
MW-21AMW-21BMW-21C
MW-22AMW-22B
MW-23AMW-23BMW-23C
MW-24AMW-24B
MW-25MW-26MW-27MW-28MW-29
MW-32AMW-32B
MW-33MW-34
MeasuringPoint
Elevation^
259.04258.75
270.12269.87269.74
267.18267.28267.37
269.99
270.35
263.87263.54
263.23263.12
261.38261.96261.49
253.02252.75
267.51267.40267.34
256.01255.76
273.25271.04275.78277.76260.73
250.71251.43
254.39260.82
LandSurface
Elevation
±267.82±256.62
±267.97±268.05±267.86
±264.52±264.69±264.7
±267.84
±267.95
±261.13±260.52
±260.55±260.49
±259.08±259.19±259.34
±250.70±250.10
±265.38±265.32±265.08
±253.33±253.07
±270.55±268.49±273.76±275.65±260.70
±248.69±248.63
±251.59±258.11
r
ScreenedInternal
Elevation
255.82-240.32227.12-221.12
250.97-240.97228.55-218.55194.86-184.86
244-52-234.52212.19-202.19
179.7-169.7
222.84-212.84
195.95-185.95
237.13-227.13221.52-211.52
245.55-235.55225.49-215.49
255.08-245.08239.19-229.19215.34-205.34
236.9-226.9216.6-206.16
245.38-235.38217.32-207.32181.08-171.08
233.83-223.83222.07-212.07
266.55-258.55265.49-255.49268.76-258.76270.65-260.65
258.2-248.2
241.69-231.69216.83-206.83
210.09-200.09250.82-240.82
ScreenedInterval/Depth
12-27.529.5-36.5
17-2729.5-49.5
73-83
20-3052.5-62.5
85-95
45-55
72-82
24-3439-49
15-2535-45
4-1420-3044-54
13.8-23.833.5^3.5
20-3048-5884-94
19.5-29.531-41
4-123-135-155-15
2.5-12.5
7.0-17.031.8-41.8
41.5-51.510-20
ScreenedMaterial
Gravelly, silly sandFractured Bedrock
SandSandSilt and sand
Sand and gravelSandSilt and sand
Coarse sand andgravelCoarse sand andsilt
Silty sandBedrock
SandSand
Sand and siltSand and gravelSand and silt
Sand and gravelSand and silt
Sand and gravelSand and siltSand and gravel(till)
Sand and gravelTill
SandSandSand and gravelSand and gravelSand
SandSand and silt
Silty sandGravelly sand
rTop of Outer Steel Casing - Cap Removed.2176-150/HAZ/5146 2-27
TABLE 2-5 (Cont'd)
SUMMARY OF GROUNDWATER MONITORING WELLSSAVAGE WELL SITE
Well Number
MeasuringPoint
Elevation-^-
LandSurface
Elevation
ScreenedInternal
Elevation
ScreenedInterval/ Screened
Material
Pre-Exi$tiqg MQPJtoring Wells
MMMI-7MI-10MI-11
MI-12MI-19MI-20
MI-22MI-24
MI-25MI-26MI-27MI-28
MI-29MI-30MI-31MI-63
HM-1
256.14256.56255.17,254.612
253.48277.93277.93
272.34273.41
272.35272.35273.43271.76
270.68268.68267.14267.64
±254.36±254.96±252.67±252.11
±251.83±275.6±275.6
±270.0±270.6
±270.04±270.04±270.7±270.26
±269.18±265.45±265.64±264.64
215.36-205.36? -223.96
208.67-205.67212.11-209.11199.11-196.11208.83-202.83
210.6-195.6265.6-235.6
171.0-156.0265.6-185.6
169.04-159.04262.04-182.04
257.7-192.7236.76-216.76
±237.68-217.68233.46-193.46229.64-211.64241.64-201.64
39-49? -3144-4740-4353-5643-4965-8010-40
99-1145-85
101-1118-88
13-7835-55
31.5-51.532-7236-5423-63
269.19 ±267.19 ±264.19-189.19
SandSand and gravelSand and gravelSand and gravel
Sand and gravelBedrockSand, gravel andcobbleBedrockOverburden
BedrockOverburdenOverburdenSand, gravel andtillSand and siltOverburdenOverburdenOverburden
3-83 Overburden
* Top of Outer Steel Casing - Cap Removed.2TopofPVC.
2176-150/HAZ/5146 2-28
TABLE 2-5 (Cont'd)
SUMMARY OF GROUNDWATER MONITORING WELLSSAVAGE WELL SITE
Well Number
MeasuringPoint
Elevation^Total
ScreenedInternal
ElevationScreenedInterval
ScreenedMaterial
Milford Fisb Hatchery Wells
FH-9FH-10FH-11FH-12FH-13FH-14FH-15FH-16FH-17FH-18
FH-19FH-20FH-21FH-22 (MI-66)FH-23FH-24FH-25 (MI-67)FH-26FH-27 (MI-68)
269.76+268.0+266.0
262.46269.05
±269.0265.63
+259.0+270.0
255.01
256.17254.53255.19255.05254.33254.38254.84254.35253.32
52.063.062.075.056.042.038.057.0
28.0
38.028.029.028.032.028.031.025.043.0
±210-205.0? -±204.0
205.46-187.46? -213.05
±237.0-227.0? -227.63? -202.0
±234.01-229.01
±233.53±234.19±233.05±228.33±231.38±231.84±234.35±217.32
-228.53229.19230.05223.33226.38226.84229.35212.32
Overburden58-63 Sand and gravel
Overburden57-75 Sand and gravel
Overburden32-42 Overburden
OverburdenOverburdenOverburden
21-26 Silry sand andgravelOverburden
21 -26 Sand and gravel21-26 Overburden22-25 Overburden26-31 Overburden23-28 Sand23-28 Sand and gravel20-25 Sand and gravel36-41 Fine to coarse
sand
Residential Wells
RW-1RW-2RW-3RW-4RW-5RW-6RW-7RW-8RW-9
.
.
280.082..._
271.453
340.012.0420.0165.0.
20.0300.035.0
jTTop of outer steel casing - cap removed.* Top of Brick, SE Corner of Well.3 Top of Brick.
76-340
130-420
BedrockOverburdenBedrockBedrockOverburdenOverburdenBedrockOverburdenBedrock
2176-150/HAZ/5146 2-29
TABLE 2-5 (Cont'd)
t.Y OF GROUNDWATER MONITORING WELLSSAVAGE WELL SITE
PIEZOMETERS
Measuring PointPiezometer I.P.- Elevation Screened Interval/Depth
P-l 279.00 13.9-14.9P-2 271.32 17.0-18.0P-3 262.71 15.9-16.9P-3A 257.53 4.0-5.0P-5 266.79 11.5-12.5P-6 263.87 14.5-15.5P-7 265.28 14.5-15.5P-8 266.99 14.5-15.5
P-9A 254.88 7.0-8.0P-9B 254.57 9.2-10.2P-10 253.91 7.5-8.5P-ll 254.54 7.5-8.5P-12 253.40 9.0-10.0P-13 250.84 7.5-8.5P-14 2,8.68 7.0-8.0P-15 253.03 7.0-8.0P-16 260.30 12.0-13.0
P-17A 252.54 8.0-9.0P-17B 253.66 12.0-13.0
SP-1 3.5-8.5SP-2 1.0-6.0SP-3 4.5-9.5SP-4 2.5-7.5SP-5 2.5-7.5SP-6 3.0-8.0SP-7 4.5-9.5SP-8 2.0-7.0SP-9 1.5-6.5SP-10 1.0-6.0SP-11 8.5-9.5SP-18 4.5-7.5
HP-1 254.51 1.0-6.0HP-2 253.24 1.5-6.5HP-3 252.43 1.5-6.5HP-4 250.10 1.0-6.0
Top of Casing Caps Removed (Piezometers are constructed of a single casing, either PVC orSteel).
* SP-1 through SP-11 installed and surveyed by NHDES.
2176-150/HAZ/5146 2-30
6. Trailer park septic system leach field.
7. Location to the east of the trailer park access road where a paving companyreportedly parked and cleaned trucks.
8. Body Magic autobody shop - former location of Talarico Pontiac.
9. Gravel pit operations near Savage Well, as observed on historical aerialphotographs.
10. Medlyn Motors automobile dealership and garage.
11. New location of Talarico Pontiac - automobile dealership and garage.
12. George Brox, Inc., stump dump - located east of Perry Road, approximately 800feet south of Hitchiner Plant No. 3.
13. Private heavy equipment/garage operation on Perry Road, adjacent to HitchinerPlant No. 3.
14. Suburban Propane.
15. George Brox, Inc./Xorb, Inc., sand and gravel and asphalt facilities.
16. AMP Technology - manufacturers of keyboards, etc.
17. Abbott Woolen Mills, located upstream of the project area in Wilton, NewHampshire - reportedly disposed of used chemicals, including acid dyes, by directdumping into the Souhegan River.
18. G&T Construction Co. - construction equipment rental and lease business operatedin the late 1950's.
19. Hayward Farms Restaurant and Ice Cream Plant. O' 3.2 SURFACE WATER HYDROLOGY
Water level measurements, flow measurements, discharge calculations, and drainage
calculations have been used to gain an understanding of the hydrology of surface water systems
at the site and their relationship to groundwater flow. The location of all surface water gauging
stations are indicated on the Site Base Map (Plate I) and on Figure 2-2.
Eight sets of water level measurements have been performed at the staff gauge/piezometer
stations on the discharge stream and three sets have been performed at the stations on the
Souhegan River, allowing comparison of groundwater and surface water elevations. This data is
presented in Table 3-2.1. Piezometer construction data was provided in Table 2-5.
At each of six flow measurement stations (WLR-1, SG-2, SG-3, and WLR-5 on the
Souhegan River; WLR-3 and WLR-4 on the Discharge Stream), five to seven individual flow
2176-150/HAZ/5146 3-10
measurements and discharge calculations were performed in accordance with the methods
described in Section 2.4.2. Tables presenting the measurements and calculations are included in
Appendix 27B. A summary of the discharge measurements completed for these flow
measurement stations is included as Table 3-2.2, along with stage height measurements
completed at adjacent staff gauges at the time of the flow measurements. The total uncertainty
of error inherent in sfrearn flnw r»tta is g»noitdlji wry temple* ffld difficult to assess. Directly
measured values such as stream stage, channel width, or stream depth present some chance for
error and stream discharge calculations are more complex because the discharge determination
is made using a combination of scalar and vector quantities, each having inherent errors that are
additive. The measured total discharge values may deviate from the actual discharge values by
more than 10 percent and should be considered semi-quantitative.
Continuous records of water level fluctuations were provided by water level recorders at
stations WLR-1 and WLR-5 in the River and at stations WLR-3 and WLR-4 in the Discharge
Stream. The water level recorder strip charts are included as Appendix 29. The strip chart
records were translated to a digital stage height versus time record using a digitizing tablet,
resulting in the continuous stage height hydrographs included as Figures 3-4.1 through 3-4.4.
The strip chart records were not adjusted for differences between river stage and recorder chart
These charts present an essentially continuous record of stage height over time for the period of
measurement extending for approximately January, 1988, through October, 1989.
Table 3-2.3 presents a summary of the records as well as a comparison of chart stage data
with measured stage data from staff gauges. There are some gaps in the records due to freezing
conditions during which the recorder did not operate, mechanical problems which caused the
recorder to jam or to otherwise misfunction, or operator error which resulted in loss of record
due to failure to change the strip chart at the end of the 16 day recording cycle. Gaps in the
records are noted on Table 3-2.3 along with explanations for the missing records. Periods of flat
record also occur as a result of equipment malfunction, friction of the side wall, or water frozen
in the recorder station. Periods of flat record on charts include: WLR-1 (12/22/88-12/28/88 -
float frozen, 12/1/89-1/12/90 - float frozen), WLR-3 (8/30/88-9/11/88 - float caught on side of
wall), WLR-4 (11/6/88-11/19/88 - cause unknown), and WLR-5 (12/22-12/28/88 - float frozen,
12/1/89-1/9/90 - float frozen). Other periods of flat recorded include: WLR-3; 7/20-8/5/89,
10/3-10/14/89 and WLR-4; 1/3-1/12/89. The charts have been analyzed and the records for
these periods appear to be good. The flat record is a result of very little variation in stream flow
during these times.
2176-150/HAZ/5146 3-10.1
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In order to examine the relationship between precipitation and stream stage, daily
precipitation records for the period of interest were obtained from the National Oceanic and
Atmospheric Association's (NOAA) Milford weather station, Index No. 27-5412-2, located
approximately 1.5 miles northeast of the site. The air temperature and precipitation data are
included in Appejidix 28. Figure 3-4.5 presents air temperature and precipitation data at the
same time scale as the hydrographs to allow comparison of precipitation events with the
hydrograph records. The hydrographs for the record of interest are consistent with
meteorological effects and correspond well with precipitation events. Large fluctuations in stage
records (i.e. WLR-5 in June and July, 1989) can generally be correlated with precipitation. June
and July, 1989 were very wet months as they received 6.41 and 6.45 inches of rain, respectively.
A comparison of the hydrographs for the three Souhegan River stations show similar
fluctuations in response to precipitation. /. (u
Inspection of the records suggests that the discharge stream may be losing water to the
aquifer between station WLR-3 and WLR-4 (average discharge decreases), while the Souhegan
may be gaining water due to baseflow between stations WLR-1 and WLR-5. This suggests that
the discharge stream may be elevated above the ground water table while the Souhegan interacts
dkectly with the groundwater table. These characteristics are examined in greater detail in the
following sections, which discuss the results of gauging and flow measurements at various
points along the discharge stream and the river.
3.2.1 Discharge Stream
Based on surface water and groundwater level measurements, the uppermost portion of the
discharge stream, between SW-5 and SW-20, appears to discharge to groundwater. Comparison
of the August 24, 1989, surface water levels obtained at stations SW-5 and SW-20 with adjacent
groundwater levels indicate that the discharge stream is approximately 3 to 5 feet higher than the
water table. Previous measurements reported by Roy F. Weston, Inc., (1984) indicated that the
stream in this area was 3 to 7 feet higher than groundwater. It would appear that the stream is
higher than the water table under most typical conditions. Furthermore, estimates of the
groundwater drawdown created by pumping of the Hitchiner well indicate drawdowns of less
than one foot in the vicinity of the discharge stream (see Appendix 31). The drawdown is not
large enough to account for the observed difference between stream and groundwater
elevations. It appears that even in the absence of pumping at Hitchiner, the upper portion of the
stream would not intercept the groundwater and that this portion of the stream thus receives flow
only from industrial discharges, or from precipitation events and overland runoff, and serv<*<; as a
source of recharge to groundwater.
2176-150/HAZ/5146 3-10.10
It appears that the central portion of the discharge stream (in the vicinity of WLR-3) both
receives flow from and discharges to the groundwater, dependent on fluctuations in groundwater
and surface water levels. Comparison of staff gauge and piezometer measurements indicate that
at WLR-3 the discharge steam elevation was lower than the groundwater table on four of the
nine days when water measurements were made, but was higher than the water table on four
days, and was at the same level on one day (see Table 3-2.1). The difference in elevation
between the stream level and the groundwater level ranged from -0.75 feet to +0.52 feet.
Groundwater levels exhibit a more pronounced fluctuation than do stream levels. Over the
period of the measurements, from February 2 to September 28, 1989, the water level in the
stream fluctuated by .42 feet, while the groundwater level fluctuated by 1.06 feet.
The downstream portion of the stream (i.e., the vicinity of WLR-4) consistently discharges
to the groundwater. Water level data indicates that the stream was higher than the water table on
seven of the nine days, is lower than the water table on only one of the days, and is
approximately level with groundwater on the other day. The difference in elevation between the
discharge stream and groundwater ranged from +1.09 feet to -0.2 feet. Stream levels fluctuated
by 0.37 feet while groundwater levels fluctuated by 1.57 feet.
Despite the fluctuations in the relationship between stream levels and groundwater levels
along the central part of the discharge stream in the vicinity of WLR-3, the discharge stream as a
whole can be characterized as generally discharging to the groundwater.
Comparison of the semi-quantitative discharge rates, with greater than ten percent error, at
stations WLR-3 and WLR-4 suggests the above interpretation. Four of five sets of discharge
measurements indicate losses between WLR-3 and WLR-4 ranging from 0.09 to 0.69 cfs
(58,000 to 446,000 gallons per day (gpd)). The only measured gain between WLR-3 and WLR-4
was on May 12, 1989, when a gain of 1.50 cfs (469,000 gpd) was calculated. This gain was
coincident with a major storm event; as evidenced by the hydrographs and the precipitation
record. By comparison, previous investigations by NHWSPCC indicated that the stream was
losing between 97,000 (.15 cfs) and 116,000 gallons per day (.18 cfs). These measurements
were completed during a period of relatively low flow in June and August, 1988. An exclusion
of the anomalously high measurement obtained at WLR-4 on May 12, 1988 indicates that the
average net loss between the two gauging stations is 0.36 cfs (233,000 gpd).
2176-150/HAZ/5146 3-10.11
It should be noted that some of the measured discharges included in Appendix 27B were
not included in the analysis or on Table 3-2.2. On several occasions, two discharge
measurements were obtained for both WLR-3 and WLR-4, one upstream of the gauge and one
downstream, in an attempt to determine which location yielded the more accurate data. On these
occasions, the measurements with the most data points were used as it was felt it represented
more accurate conditions. On 6/16/89, two measurements were obtained for WLR-4. However,
both measurements were considered poor and were not subsequently used for analysis. On
6/29/89, two measurements were obtained for WLR-3 and the downstream measurement was
used (1.75 cfs) as it was based on more data points. Also on 6/29/89, two measurements were
obtained at WLR-4. However, neither measurement was used as they were judged to be poor.
On 7/14/89, two measurements were obtained for WLR-3 and the downstream measurement was
used (2.21 cfs) as it was based upon more data points.
The Discharge Stream receives process water discharges from several individual outfall
pipes at the Hitchiner facility, including three located at the ponded area (SW-5) at the upstream
end of the Discharge Stream, and one at the location of SW-6. Discharge from all the Hitchiner
outfalls leaves the Hitchiner facility via a weir located adjacent to SW-6, and the flow at this
weir is metered on a daily basis (Station WLR-2). These measurements are included in the
Appendices. Daily discharge measurements from January, 1989 through August, 1989, indicate
a daily range from (140,000 gpd) (.22 cfs) to (550,000 gpd) (.85 cfs), and monthly averages
ranging from 160,000 gpd (.25 cfs) in January to 347,000 gpd (.54 cfs) in May.
The Hendrix facility did not meter its discharges on a daily basis, but monthly
measurements at the two outfalls which formerly discharged to the Discharge Stream indicate
discharges of approximately 100,000 gpd (.15 cfs) and 50,000 gpd (.08 cfs), respectively, for a
combined approximate average total of 150,000 gpd (.23 cfs). Thus, the total contribution to the
discharge stream from the outfall at the Hitchiner weir and the Hendrix process water outfalls
averaged between 310,000 gpd (.48 cfs) and 497,000 gpd (.77 cfs). By comparison, discharges
measured at WLR-3 range from 1.46 cfs to 2.07 cfs or approximately 749,000 to 1.3 million gpd,
with an average of 1.86 cfs, or approximately 1.20 million gpd. The average discharge at
WLR-4 was 1.80 cfs, or approximately 1.16 million gpd.
Thus, semi-quantitative discharge estimates at stations WLR-3 and WLR-4 are higher than
would be expected based on the measured discharges from the Hitchiner and Hendrix facilities,
assuming that these discharges comprise the bulk of the flow in the discharge stream.
2176-150/HAZ/5146 3-10.12
It is possible that this discrepancy is, in part, the result of the contribution of flow to the
Discharge Stream from sources other than the Hitchiner and Hendrix outfalls.
First, existing data indicates that the stream level and groundwater level at WLR-3, in the
middle portion of the discharge stream, are very close and that this portion of the stream receives
flows from the groundwater during routinely fluctuating groundwater conditions.
Secondly, infiltration of precipitation and surface water runoff appears to have a
significant input to flows in the discharge stream. For example, discharge measurements at the
Hitchiner weir during a storm indicated a 332,200 gpd (.51 cfs) increase in discharge over a
24-hour period from February 2 to February 3. The records consistently show significant
increases in discharge associated with rainfall. The length of the discharge stream upstream
from the Hitchiner weir is approximately 600 feet, while the exposed length of the stream
between the weir and WLR-3 is approximately 1,200 feet and the length of the stream between
WLR-3 and WLR-4 is approximately 2,200 feet. Given the observed increase in discharge at the
Hitchiner weir due to precipitation, it is reasonable to assume that additional significant
increases in discharge resulting from precipitation and runoff occur between the weir and
WLR-3. The upper portion of the discharge streams receives surface water runoff from adjacent
paved areas as well as discharges from storm drains and roof drainage at the Hitchiner and
Hendrix facilities.
3.2.2 Souhegan River
Based on the groundwater contour map developed from August 24, 1989 data (Figure
3-14), and based on comparison of staff gauge levels in the Souhegan River with groundwater
levels in adjacent piezometers and monitoring wells, some general observations on the
relationship between flows can be made. In the western portion of the site (SG-1A to SG-2A),
the flow gradient along the Souhegan River and the hydraulic gradient of the aquifer are
relatively steep and groundwater appears to flow southeasterly away from the river. Through the
central portion of the site, as the flow gradient decreases, there is a transition zone where no
clear hydraulic gradient exists between the River and the groundwater, and finally, in the eastern
portion of the site (east of SG-3), groundwater appears to discharge to the river.
The results of stream gauging and discharge calculations provide additional data that
allows an approximation of gains and losses along the Souhegan River and suggests variations (^7
from the interpretations based solely on groundwater contour data and on comparative
groundwater and surface water levels.
2176-150/HAZ/5146 3-10.13
For the upper reach of the river, between WLR-1 and SG-2, two of four sets of
measurements suggested gains in discharge. Estimated discharges ranged from approximately
70 to 307 cfs at WLR-1 and from 124 to 306 cfs at SG-2. The average net gain based on all four
estimates was 11.55 cfs.
During the. round of water level measurements collected on August 24, 1989, the water
level in the river at SG-2A, located between WLR-1 and SG-2, was higher than groundwater
levels at piezometer P-2, on the south side of the river, and at MW-2, on the north side of the
river, apparently indicating that the river was losing to the groundwater. Discharge data for
WLR-1 and SG-2 is not available for this date. It is possible that the river is losing along the
upper reach under low flow conditions, but generally gaining under other flow conditions in part
due to pumping at the Milford Fish Hatchery (see Summary), but that it is a net losing reach only
at low flow conditions).
For the middle reach of the river, from SG-2 to SG-3, three of four measurements _suggest
losses, with an average net loss of 17.05 cfs based on all four measurements. Estimates/
discharges ranged from 65 to 303 cfs at SG-3.
Discharges along the lower reach of the river, between SG-3 and WLR-5, are the best
defined of the three reaches, as six sets of flow measurements were obtained at each of these
stations. All six measurements suggest gains, with an average gain of 22.01 cfs based on all six
measurements.
3.2.3 Summary
The Hitchiner-Hendrix Discharge Stream receives flow primarily from industrial
discharges along with precipitation and overland runoff, and is a net losing stream, discharging
flow to groundwater under nearly all conditions. However, the central portion of the stream also
receives flow from groundwater during high groundwater level conditions.
The interaction between the Souhegan River and the aquifer is variable depending on
fluctuating contributions from rainfall and surficial runoff, as well as the influences of various
groundwater pumping locations and surface water discharges. The complexity and limited
measurements, including accuracy variances, contribute to variations observed in the magnitude
of discharges. Some deviation from consistent net losses or gains in discharge along individual
reaches are possibly explained by the limited available data.
The main channels of rivers are usually gaining reaches, however, the upper reaches of the
Souhegan River (WLR-1 through SG-2; and SG-2 through SG-3) are at times losing reaches, in
part due to the effects of high yield pumping (>2 million gallons per day) at Milford Fish
Hatchery production wells to the north. It is likely that the WLR-1 to SG-2 and the SG-2 to
2176-150/HAZ/5146 3-10.14
SG-3 reaches as discharge some flow to groundwater under all conditions due to the Milford
Fish Hatchery pumping effects, but is a net losing reach only under certain flow conditions. The
WLR-1 to SG-2 reach has one tributary discharging to it which, along with overland water
runoff, contributes to the observed gains. The central reach between SG-2 and SG-3 is a
generally losing reach, suggesting that groundwater pumping at the Milford Fish Hatchery wells
is resulting in reduced groundwater discharge to the river on the north side of the river and
possibly inducing infiltration from the river to the aquifer in the vicinity of these wells. The
central reach of the river has two tributaries discharging to it. The first is an unnamed brook
flowing northwest to southeast and discharging to the north side of the Souhegan immediately
downstream of SG-2. The second is the Hitchiner-Hendrix Discharge Stream which discharges
to the Souhegan immediately upstream of SG-3. These tributaries along with surface runoff
contribute to the observed gains.
The downstream reach of the river between SG-3 and WLR-5 receives flow from
Purgatory Brook, which includes discharges from the Milford Fish Hatchery, and from surface
runoff. Having recovered from influences of pumping at the Milford Fish Hatchery, this reach is
a generally gaining reach. The nature of the discharge of groundwater to the river along this
reach is further discussed in Section 5.0, Fate and Transport.
In order to provide an estimate of the accuracy of the discharge calculations for the
discharge stream, an additional set of flow measurements was performed at a location
immediately downstream of the Hitchiner weir on October 16, 1989. The discharge value
obtained by this method was compared to discharge values calculated for this date by the ISCO
flow meter located at the weir and by using a standard V-notch weir equation. The discharge
value obtained by this method was compared to discharge values calculated for this date by the
ISCO flow meter located at the weir and by using a standard V-notch weir equation. The
discharge value obtained by the cross-sectional area and flow meter method was .73 cfs (472,000
gpd), approximately 30% higher than the .49 cfs (317,000 gpd) value obtained by the ISCO
meter and the .47 cfs (304,000 gpd) value obtained by the V-notch weir equation.
This results of these measurements indicate that the measured discharge value is 30%
higher than that indicated by the Hitchiner flow meter and weir, but does not necessarily indicate
that all measurements have an error of 30%. No determination of accuracy has been made for
the discharge measurements as a whole. However, as previously discussed, it appears that the
measured discharge values may deviate from actual discharge values by more than 10 percent
and should be considered semi-quantitative.
2176-150/HA^5146 3-10.15
No estimate of accuracy was made for the Souhegan River discharge calculations. An
effort was made to compare the Souhegan River flow data with long-term data from a USGS
gauging station. However, the closest long-term USGS gauging station is located on Stony
Brook, a tributary of the river located approximately 2 miles upstream from WLR-1, the most
upstream on-site gauge. Additionally, the available gauging data for this station only extended
through September, 1988, prior to the period of this study.
The total uncertainty of error inherent in stream flow data is generally very complex and
difficult to assess. Directly measured values such as stream stage, channel width, or stream
depth present some chance for error and stream discharge calculations are more complex
because the discharge determination is made using a combination of scalar and vector quantities,
each having inherent errors that are additive. The measured total discharge values may deviate
from the actual discharge values by more than 10 percent and should be considered
semi-quantitative.
2176- 150/HAZy5146 3-10.16
was collected when the well was pumping again within the normal rate, approximately 320,000
gallons per day. The well had been pumping at the rate of 228,000 gpd for at least two days
prior to the water level measurements on July 6, 1989. The exact time of reduction of pumping
rate is not known. On July 11, 1989, two days prior to the 2nd round of water levels, the rate
increased to approximately 360,000 gpd. The pumping rate, however, returned to near normal
on July 13, 1989.
The data, as interpreted on resulting groundwater contour maps, (Figures 3-15 and 3-16),
allow inference of a cone of depression when the well is pumping at 320,000 gpd, but indicate a
much less pronounced inferred depression caused by pumping at 200,000 gpd. The data also
indicate a more distinct inferred cone of depression at the Hendrix production well when the
Hitchiner well was at 2/3 rate.
3.4.5 Analysis of Fish Hatchery Pump Test Data
In addition to the effects on groundwater flow produced by the two industrial production
wells, groundwater flow at the site area is also influenced by production wells at the Fish
Hatchery located on the north side of the Souhegan River. See Figure 1-3 for Fish Hatchery
production well locations. Details of well construction and pumping rates were previously
provided in Table 1 -1.
HMM reviewed several hydrogeological reports prepared for the fish hatchery and
conducted a limited analysis of the pump test data that is contained within a report prepared in
1988 for one of the fish hatchery's new production wells (Well No. 5). This particular
production well is located approximately 800 feet to the north of the Souhegan River. During
the pump test, five observation wells were included for collection of time-drawdown data. The
radii from the production well to these observation wells ranged from 30' to 750'. The pump
test was run for four days with the production well pumping continuously at 1,000 gpm. HMM
constructed distance-drawdown plots at various time intervals from the time-drawdown data
contained in the pump test report. Pump test analyses are included in the Appendices.
The following discussion addresses the distance-drawdown plot for these five observation
wells at a period of two days after the beginning of the pump test. The distance-drawdown data
plots as a straight line on semi-logarithmic paper which is normal and expected for this type of
pump test. The important information observed from this distance-drawdown plot is that after
two days of continuous pumping, the cone of influence is measured in the observation well
located 750' from the pumping well. By extending the straight line plot to the zero drawdown
intercept, we would anticipate that the radius of the cone of influence after two days is
approximately 1,100'. Since the pumping well that is being tested is approximately 800' from
2176-150/HAZ/5146 3-42
TABLE 3-8
Groundwater Elevations at the Savage Well Sitec
Well *
HM 1
HM 1A
HU 1A
HW IB
HU 1C
MU 2A
HU 28
HU 2R
HU 3
HU 4A
HU 4B
HU 4R
MU SA(AH)
HU SB (AM)
HU 5ACPH)
HU 5BCPH)
HU 6A
HU 6B
HU 7A
HU 78
HU 8A
HU 8B
HU 9A
HU 9B
HU 9C
HU 10A
MU 106
MW IOC
MU 11A
HU 11B
HU 11R
HU 12A
HU 128
HU 13A
HU 13B
HU 14 A
HU KB
HU 14R
HU ISA
HU 1SB
HU 16A
HU 168
HU 16C
HU 17A
HU 17B
HU 17C
HU 18A
HU 18B
HU 19A
HU 198
Measuring
PointElevation
NS269.19281.62
281.62
281.42
269.32
269.19
268.95
270.59
268.43
268.73
268.25
269.82
269.69
269.82
269.69
269.04
269.08
264.30
264.26
263.87
263.77
267.96
267.84
268.23
264.33
264.51
264.87
262.84
262.88
263.21265.91
266.06
259.78259.50
254.72255.00255.62
259.04258.75270.12
269.87269.74
267.18
267.28267.37
269.99
270.35
263.87
263.54
2-Feb 1989
Depth
8.85
8.43
8.47
8.72
11.31
11.23
10.14
10.37
11.10
11.42
11.77
6.74
6.91
7.64
6.40
6.597.11
12.58
12.45
5.304.965.735.796.4316.3716.30
Ilevation
260.89
260.72
260.23
258.51
258.46
258.90
258.71
256.86
256.42
256.46
257.59
257.60
257.23
256.44
256.29
256.10
253.33
253.61
254.48254.54
248.99
249.21249.19
242.67242.45
3-Feb 1989
Depth
8.85
10.43
13.57
9.54
7.82
8.00
7.45
11.25
11.17
11.30
11.23
6.75
6.60
7.51
7.40
5.765.886.4916.5816.40
Elevation
272.77
271.19
267.85
261.05
260.61
260.73
260.80
258.57
258.52
258.52
258.46
257.55
257.66
256.36
256.37
248.96
249.12249.13
242.46242.35
6-Jul 1989
Depth
6.70
6.89
6.34
9.75
9.71
9.34
9.46
6.14
5.94
7.46
8.30
10.74
10.96
11.48
6.42
6.61
7.40
10.97
10.64
10.41
8.93
9.02
9.53
11.04
11.39
ilevation
261.73
261.84
261.91
260.07
259.98
259.70
259.62
258.16
258.32
256.41
255.47
257.22
256.88
256.75
257.91257.90257.47
259.15
259.23259.33258.25258.26257.84258.95258.96
13-Jul 1989
Depth
7.24
7.41
6.86
10.76
10.69
9.75
9.96
6.42
6.24
7.61
7.30
10.95
11.24
11.63
6.63
6.827.58
11.21
10.89
10.67
9.20
9.289.7411.67
12.04
Elevation
261.19
261.32
261.39
259.06
259.00
259.29
259.12
257.88
258.02
256.26
256.47
257.01
256.60
256.60
257.70
257.69
257.29
258.91
258.98259.07257.98258.00257.63258.32258.31
24-Aug 1989
Depth
7.94
9.95
13.00
8.90
8.92
9.06
8.85
7.23
7.42
6.86
11.01
11.00
9.92
10.10
6.35
6.14
7.62
7.14
11.00
11.30
11.53
6.73
6.92
7.67
7.23
7.44
7.96
12.56
12.44
5.49
5.14
5.78
5.896.4716.7716.61
11.35
11.0010.789.30
9.379.6511.8012.17
8.48
8.12
ilevation
273.68
271.67
268.42
260.42
260.27
259.89
261.74
261.20
261.31
261.39
258.81
258.69
259.12
258.98
257.95
258.12
256.25
256.63
256.96
256.54
256.70
257.60257.59257.20
255.61
255.44
255.25253.35253.62254.29254.36248.94249.11249.15
242.27242.14258.77
258.87258.96257.88
257.91257.72258.19258.18
255.39255.42
25-Aug 1989
Depth
9.00
9.04
10.88
Ilevation
260.15
258.86
Note: Land surface elevations and measuring points are specified in Table 2-5
TABLE 3-8 CONTINUEDGroundwater Elevations at the Savage Well Site
Well «
MW 20AHU 20B
HW 21A
HW 218
HW 21C
HU 23A
HW 238
HW 23C
HW 24A
HW 24 B
HW 25
HW 26
HW 27
HW 28
HW 29
HI 4
HI 7HI 10HI 11
HI 12HI 19
HI 20
HI 21
HI 22
HI 23
HI 24
HI 26
HI 27
H! 28
HI 29
HI 30
HI 31
HI 32
HI 34
HI 63
FH 22(HI66)
FH 25(HI67)
FH 27(HI68)
MeasuringPoint
Elevation263.23263.12261.38261.96
261.49
267.51
267.40
LJ67.34
258.69
258.35273.25271.04
275.78277.76
260.73
257.14
256.56
255.17
254.61
253.48
277.93
277.93
275.34
272.34
272.34
273.41
272.35
273.43
271.76
270.68
268.69267.14
273.47279.59267.64
255.05
254.83253.30
2-feb 1989
Depth
.
12.68
12.6210.16
10.8612.4611.50
12.6110.31
8.89
13.15
8.95
Elevation
265.25
265.31
265.18
261.48
260.95
260.85
260.82
261.45
258.25260.32
258.69
3-Feb 1989
Depth
5.71
6.17
12.67
12.65
11.39
10.98
11.54
9.92
10.83
15.77
Elevation
251.43
250.39
265.26
265.28
260.95
261.36
260.81
260.76
257.86
263.82
6-Jul 1989
Depth
9.29
8.5910.098.28
.levation
262.47262.09258.60258.86
13-Jul 1989
Depth
9.60
9.2910.528.60
levation
262.16261.39258.17258.54
24-Auo 1989
Depth8.608.509.50
10.11
9.62
10.30
10.58
10.789.11
8.77
6.37
6.31
10.86
10.75
5.12
5.73
6.146.24
6.40
6.10
12.42
12.5810.39
11.00
12.3011.29
12.33
9.90
9.44
10.628.7213.0713.89
8.14
6.15
ilevatlon254.63254.62251.88251.85251.87257.21256.82256.56249.58249.58266.88
264.73264.92267.01
255.61
251.41
250.42
248.93
248.21
247.38
265.51
265.35264.95
261.34
261.11
261.06
261.10261.86261.24258.07258.42260.40265.70
246.91
247.15
25-Aug 1989
Depth
9.04
leva t ion
258.60
Note: l and surface elevations and measuring points nrc specified in Table 2-5
TABLE 3-8 CONTINUED
Piezometer and S ta f f Gauge Water levels
Piezometer
Staff Gauge
P 1
SG 1*
P 2
SG 2A
P 3A
P 38
ULR 3
P 4
ULR 4
P 5
P 6
P 7
P 8
Measuring
Point
E I eva t i on
279.00
271.32
261.14
262.71
257.53
255.16
253.72
250.78
266.79
263.87
265.28
266.99
2-feb 1989
Depth
'
2.03
0.86
Elevation
255.50
256.02
3-Feb 1989
Depth
0.85
3.49
0.54
Elevation
256.01
250.23
251.32
14-Apr 1989
Depth
1.52
0.53
2.94
0.47
Elevation
256.01
255.69
250.78
251.25
21 -Apr 1989
Depth
1.39
0.54
2.76
0.54
Elevation
256.14
255.70
250.96
251.32
28 -Apr 1989
Depth
1.66
0.52
3.23
0.42
Elevation
255.87
255.68
250.49
251.20
12-May 1989
Depth
1.89
0.58
2.11
0.63
Elevation
255.64
255.74
251.61
251.41
Piezometer
Staff Gauge
P 1
SG 1A
P 2
SG 2A
P 3A
P 38
ULR 3
P 4
ULR 4
P 5
P 6
P 7
P 8
Measuring
Point
•levat ion
279.00
271.32
261.14
262.71
257.53
255.16
253.72
250.78
266.79
263.87
265.28
266.99
16-Jun 1989
Depth
1.10
0.54
2.48
0.45
Elevation
256.43
255.70
251.24
251.23
24-Aug 1989
Depth
11.15
9.94
0.80
7.26
0.50
3.64
0.40
11.17
8.48
10.09
11.43
Elevation
267.85
NA
261.38
261.94
255.45
255.66
250.08
251.18
255.62
255.39
255.19
255.56
25-Aug 1989
Depth
7.32
Elevation
255.39
28-Sep 1989
Depth
11.24
9.30
1.32
7.34
0.44
3.68
0.26
11.56
9.32
10.93
12.06
Elevation
267.76
NA
262.02
262.46
255.37
255.60
250.04
251.04
255.23
254.55
254.35
254.93
16-Oct 1989
Depth
11.33
9.69
1.10
7.05
0.50
3.65
0.32
Elevation
267.67
261.63
262.24
255.66
255.66
250.07
251.10
Note: Land surface elevations and measuring points are specified in Table 2 5
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6. Nutrient Removal/Transformation
7. Production Export
8. Wildlife Diversity/Abundance
9. Aquatic Diversity/Abundance
10. Recreation
11. Uniqueness/Heritage
Probability ratings for each of these 11 functions were evaluated for each of the areas.
These results are summarized for each wetland function on Table 3-11. The wetland evaluation
data sheets are included as Appendix 37. The glossary of the Wetland Evaluation Technique
(Adamus et. al., 1987) defines the probability rating as follows:
Probability Rating - A measure of how well a wetland function or value is performed by a
wetland. A probability rating is not a direct estimate of magnitude of a function or value,
rather it is an estimate of probability that a function or value will exist or occur in a
wetland to an unspecified degree or magnitude.
Two wetland systems may function at very different levels for a given parameter and yet
receive the same probability rating. Value ratings, in terms of "high", "moderate", or "low" were
assigned to each of the 10 functions for each assessment area.
Based on field observations and input from EPA, the wetlands on the site were divided
into three Assessment Areas for the purposes of this evaluation. The Souhegan River
Assessment Area No. 1 (AA1) is located on the northern portion of the site. The Tributary
Stream Assessment Area No. 2 (AA2) consists of the water course which extends through the
central portion of the site originating west of the trailer park and eventually discharging into the
Souhegan River. The Elm Street Stream Channel located on the southern portion of the site
constitutes the third Assessment Area No. 3 (AA3).
As seen in Table 3-11, most of the overall ratings were similar for the Tributary Stream
Assessment Area and Elm Street Stream Channel Assessment Area. This would be expected
due to their close proximity to each other and similarities in hydrology, soils, and plant species
composition. The results for the Souhegan River were slightly different, generally receiving
higher ratings for the various functions. This may be attributed to the overall size of the
watershed associated with this wetland system along with the size and configuration of the river
itself. All three Assessment Areas received "moderate" to "high" ratings for social significance.
This is due primarily to their location and close proximity to a highly urbanized and agricultural
environment, which increases the expected value of a wetland.
2176-150/HAZ/5146 3-56
Summary
The highest VOC levels detected in soils at the site were at the OK Tool property.
Elevated levels of PCE (up to 2400 ug/kg) were identified in soils beneath the O.K. Tool floor
slab, but these -levels are significantly lower than levels of PCE detected in groundwater
immediately downgradient of O.K. Tool. The highest concentration detected in soils outside the
building was 440 ug/kg.
The only other areas where tetrachloroethylene was detected in soils during this
investigation are Area 13, the State lot, and Area 7, the Hendrix paved storage area. The
concentrations detected at both areas (less than 100 ppb) are too low to suggest that these areas
are present sources of groundwater contamination.
Analyses of soil samples for acid and base/neutral extractable compounds (ABNs) and for
pesticides detected no contaminants above trace levels.
Metal debris is present in soils at depths of one to five feet below the ground surface
throughout an area measuring approximately 100 feet by 50 feet, located between the northwest
comer of the OK Tool building and the Souhegan River. A second area of metal debris exists
along the north side of the nearby state-owned lot, adjacent to the Souhegan River. Laboratory
analyses of soils from test pits and borings in the areas of metal debris indicate comparatively
elevated levels of a number of metals, including arsenic, barium, chromium, copper, iron, lead,
manganese, nickel, and vanadium.
PCBs were detected in soils in the vicinity of the O.K. Tool Building at levels of 0.633 to
3.48 mg/kg, and at a level of 24.0 mg/kg in a soil sample collected adjacent to the
Hitchiner-Hendrix discharge stream. /-^\(o)
4.2 GROUNDWATER
Groundwater sampling for volatile organic compound analysis was performed on January
20-27, 1989; July 24-August 2, 1989; December 11-December, 21, 1989; January 25, 1990 and
April 9-April 13, 1990. The January, 1989 sampling round also included analysis for
acid/base/neutral extractable compounds and metals. The analytical results from the
groundwater sampling program are summarized in Tables 4-5 through 4-7, included at the end of
Section 4.0, and are discussed in the following sections.
2176-150/HAZ/5148 4-8
The observed distribution of volatile organic compounds extends from the immediate
vicinity of the OK Tool facility approximately 6,200 feet eastward along the long axis of the
aquifer and, at its widest point, extends approximately 2,500 from the vicinity of Hitchiner ,( ('-f
Manufacturing and Hendrix Wire and Cable on the south side to the Souhegan River on the north
side (see Figure 4-1).
VOC contamination has also been detected in three wells at the Milford Fish Hatchery on
the north side of the Souhegan River. These wells are 1.5 to 2 inch diameter wells installed in
1985 by D.L. Maher for the purposes of siting production wells for the fish hatchery. Total
VOC concentrations of 582 ug/1 were detected at FH-27 (MI-68), located approximately 50 feet
from the River. Analysis of split samples by NHDES detected total VOC concentrations of 762
ug/1. A much lower concentration of 17 ug/1 was detected at FH-25 (MI-67) located
approximately 250 feet from the River. Analysis of split samples performed by NHDES also
detected VOCs at approximately 68 ug/1 at FH-22 (MI-66), located adjacent to FH-25 (MI-67).
Additionally, November, 1989 results from NHDES sampling of pumping wells at the private
fish hatchery (Souhegan Valley Aquaculture) indicated PCE in 3 of 5 sampled wells, FH-28, 29,
and 30 at concentrations of approximately 1, 4, and 2 ug/1 respectively. Sampling performed by
HMM in April, 1990 confirmed these results. Based on these results, as shown on Figure 4-1,
the contaminant plume appears to extend up to 300 feet north of the River along a stretch
approximately 2,000 feet in length.
The highest concentration of VOCs was detected as 22,100 ppb in MI-24 which is
screened from 5 to 85 feet in the overburden immediately to the east of OK Tool. It should be
noted when examining the analytical data and interpretive figures that several wells adjacent to
OK Tool and Hitchiner have long screened intervals (i.e., 30 to 80 feet) as compared to the
typical 10 foot well screens at the MW wells and the 5 to 15 foot well screens at most MI wells
(see Table 2-5). Concentrations of greater than 1000 ppb of total volatile organics were detected
in overburden wells MW-9, MW-10, MW-14, MW-16, MW-17, MW-20, MI-7, MI-24, MI-26,
MI-30, and MI-32. The maximum concentrations of total VOCs detected over depth in the
unconsolidated aquifer are listed in order of decreasing concentration as follows:
2176-150/HAZ/5148 4-28
Trichloroethylene
The overall extent of trichloroethylene (TCE) contamination is essentially similar to that
of PCE, with TCE being slightly more limited in extent. The highest concentration of TCE and
the likely primary source for TCE, like PCE, is in the vicinity of the OK Tool facility. TCE is a
degredation product of PCE and the principal source of TCE in the aquifer may be the
degredation of PCE, however, the occurrence of TCE and PCE in the aquifer have several(yS
differences.
1/89
3,200350..
92
7/89
1,200380380100
4/89
1,300
—43094
TCE was detected at concentrations greater than 1000 ppb only in well MI-24. It was
detected at concentrations greater than 100 ppb in the following wells.
Concentration (ppb)
Well
MI-24MW-10MW-16MW-14
- Not Sampled
The concentrations given are the maximum concentrations measured over depth in the
unconsolidated deposits. The distribution of TCE with depth of individual wells is depicted on
Figures 4-9 through 4-13.
The high concentrations (>100 ug/1) of TCE extend eastward from the vicinity of OK
Tool, consistent with the observed distribution of high concentration (>1000 ug/1) of PCE,
however, the highest TCE concentrations are an order of magnitude lower than the detected
concentrations of PCE and, outside of the elevated TCE concentration areas described above,
TCE concentrations throughout the aquifer are generally at trace levels.
The southern limit of the TCE contamination roughly coincides with Elm Street. No TCE
was detected in groundwater south of Elm Street with the single exception of 25 ug/1 at well
MW-19A. It appears unlikely that any significant secondary source of TCE exists to the south
of Elm Street.
2176-150/HAZy5148 4-31
Concentration (ppb)
WeU 1/89 7/89 12/89 4/90
MI-24MI-30MW-9MW-8MW-18MI-7MW-29MW-19
30025015041
—120ND30
ND1,300
14015015089
100
—
ND1,300
..ND
_.
—..71
39310
—33_._.__
81
- Not SampledND - No Detection
The area of the greatest concentration of TCA is north-northeast of the Hitchiner and
Hendrix Facilities.
The sampling results indicate a primary source for the TCA contamination in the vicinity
of the Hitchiner facility. TCA is not a degradation product of PCE, and thus is more likely than
other VOCs detected at the site to have originated from a separate source area (see subsequent
section, Sources of VOC Groundwater Contamination). TCA also does not appear to display a
vertical zonation within the aquifer.
Production Wells
The Savage Well was pumped at a rate of 180,000 to 240,000 gallons per day or
approximately 500 gallons per minute from 1960 to 1983. In February of 1983, the New
Hampshire Water Supply and Pollution Control Commission detected the following volatile
organic compounds in the Savage Well:
Concentration
1,1-Dichloroethane 53.1Tetrachloroethylene >862.81,2-Trans-dichloroethylene 75.91,1,1-Trichloroethane 343.9Trichloroethylene 468.0
Total VOC's 1804ug/l
There has been no recent sampling of the Savage Well, however, MI-4, a monitoring well
approximately 188 feet downgradient of the Savage Well, had concentrations of 330 ppb and 108
ppb on January and December of 1989, respectively.
2176-150/HAZ/5148 4-33
In July, 1989, PCE was detected at 2700 ug/1 at MI-22, 74 ug/1 at MI-25, and at 41 ug/1 at
MW-19B, located immediately downgradient of the Hendrix facility. TCE was detected at 16
ug/1 at MI-25 and at 7 ug/1 at MI-19, located immediately upgradient of the O.K. Tool Facility.
Also detected at MW-19B were 1,1-DCA at 14 ug/1 and 1,1-DCE at trace levels.
Wells MW-2R, 4R, 11R, and 14R are open bedrock wells which are cased off from the
uppermost weathered bedrock zone. The results of Phase I and Phase EL groundwater sampling
indicated the presence of VOCs in samples collected from deep bedrock wells MW-2R,
MW-11R, and MW-14R, but no detection at MW-4R. However, observations of bedrock core
samples indicate that the rock at MW-11 and MW-14 is not fractured and bedrock permeability
testing performed at all three wells indicates that the bedrock is not transmissive. Moreover,
field measurement of pH in groundwater samples from these wells indicate anomalously high
pH values of between 9.75 and 12.48, potentially indicative of water leaking past the
cement-bentonite grout seal from the unconsolidated aquifer (i.e., water that has been in contact
with the grout will contain some dissolved grout and will thus tend to have a high pH). MW-11
and MW-14 are located in areas where VOC contamination exists in the unconsolidated aquifer,
such that leakage of water could result in detection of contaminants in the bedrock wells.
However, VOC contaminants have not been detected in the unconsolidated aquifer at MW-2.
Thus, bedrock contamintion found at MW-2 cannot be attributed to leakage from the
unconsolidated aquifer and further monitoring of bedrock wells, including household wells, is
warranted.Three additional bedrock wells (MW-16, MW-30, and MW-31) were installed and
sampled using discrete interval packer sampling techniques in order to more clearly define
whether transmissive zones exist in the bedrock and whether contaminants could be migrating
off-site via transmissive bedrock zones. MW-16 is located within the bedrock channel directly
east of OK Tool and underlying the most-highly contaminated portion of the overburden
aquifer. MW-30 is located approximately 200 feet northeast of MW-2. MW-31 is located on
the north side of the Souhegan River near Milford Fish Hatchery wells FH-22, 25 and 27. A
detailed discussion of this program is included in Appendix 21.
The results of this bedrock well sampling program indicate that VOC contamination exists
in the bedrock at MW-16R (up to 3500 ug/1). The concentrations of VOCs in the bedrock are
significantly lower than those detected in the overlying overburden aquifer. For example, VOC
concentrations greater than 6400 ug/1 have been detected at MW-16C, the deep overburden well
which is located immediately adjacent to MW-16R. As an additional example, VOC
concentrations of 220 ug/1 were detected in the shallow bedrock well at MI-25 in comparison to
1800 ug/1 in the adjacent overburden well MI-26.
2176-150/HAZ/5148 4-35
Sampling of bedrock wells at MW-30 and MW-31 provided additional information on the
potential for migration of contaminants off-site through transmissive bedrock fracture zones.
The results of the program indicate that at MW-31, located at the downgradient leading edge of
the overburden aquifer contaminant plume, a highly transmissive fracture zone exists at depth in
the bedrock. Analytical results for six groundwater samples, two each from three test intervals,
indicate no detectable VOCs in five of the samples and 13 ug/I of TCE in the sixth.
Drilling results and yield testing at MW-30, located northeast of MW-2, indicated yields
of less than 1 gallon per minute within 300 feet of the ground surface. Sampling of the entire
open bedrock interval (160 to 304 feet below the ground surface) was performed and analytical
results indicated the presence of PCE at concentrations ranging from 80 ug/1 to 26 ug/1. Because
PCE has not been detected in the overburden aquifer in this area, the results are interpreted to
indicate the migration of PCE contamination to be bedrock in this area via low yield fractures,
located at undefined depths within the open bedrock interval.
Residences located on North River Road within the study area identified in Figure 2-1 use
bedrock wells for drinking water. Two have been identified as having shallow wells, the
remaining residences used bedrock wells for drinking water supply. Bedrock elevations in the
vicinity of the residential wells range from 170 to 210 feet. These residential wells are thus
located topographically upgradient from MW-30 in terms of both ground surface and bedrock
surface and are likely to be hydraulically upgradient. Sampling of eight residential wells (RW-1
through RW-8), including six bedrock wells, has identified no detectable concentrations of VOC
contaminants, however, as stated earlier, continued monitoring of bedrock wells is warranted.
The location of bedrock wells sampled during the RI are indicated on Figure 3-12.
Sources of VOC Groundwater Contamination
Based on the distribution of PCE contamination in groundwater at the site the occurrence
of significantly higher levels (>15,000 ug/1) of PCE in groundwater immediately downgradient
of the OK Tool Facility, and the historical occurrence of high levels in soils adjacent to the OK
Tool building (up to 1,150,000 ug/kg) and in a floor drain inside the building (up to 300,000
ug/1), it is apparent that the principal source of PCE contamination in groundwater at the site was
associated with the OK Tool facility. Specific sources and potential sources include a floor
drain, an underground tank, and a vapor degreasing tank formerly located inside the building, an
2176-150/HAZ/5148 4-36
above ground PCE tank located outside the building, and areas outside the building which were
apparently used for the disposal of oily wastes and metallic wastes. Given the highly permeable
nature of the aquifer underlying the site area and the large pumping of groundwater from the
aquifer which has redistributed the contaminated groundwater. it may not be possible to
delineate specific additional sources of PCE even though PCE was historically present at several
industries and the distribution of PCE in groundwater indicates that there may be additional
.sources at the Site.
TCE, 1,2-DCE, and 1,1 -DCE exhibit distributions throughout the site that are generally
similar to that of PCE, although these compounds are somewhat less widespread in occurrence,
are less continuously detected throughout the aquifer, and occur at concentrations which are
generally at least an order of magnitude lower than those of PCE. TCE readily forms as a
degradation product of PCE, while 1,2-DCE and 1,1-DCE form as degradation products of both
PCE and TCE. The results of the RI do not indicate any separate primary source areas for TCE,
1,2-DCE, or 1,1-DCE contamination in groundwater, and it appears that TCE, 1,2-DCE, and
1,1-DCE contaminants in groundwater at the site are derived primarily from degradation of PCE
or are impurities in the raw PCE source material, and thus are derived from a common principal
source(s).
Given the known and potential use of PCE-based solvents at other industries and
commercial operations within the site area and the results of the RI, it is possible that additional
sources within the site area contributed to the PCE and related groundwater contamination.
Other potential sources are discussed in more detail at the end of this section.
The sampling results for the soils beneath OK Tool, as previously discussed in the soils
section, do not suggest a contaminant source area which warrants source control remedial action
specific to the soils. There are, however, high levels of PCE contamination in groundwater
downgradient from the OK Tool facility, which imply the existence of contamination at depths
within the aquifer, beneath the OK Tool building, thereforejgleanup of the groundwater may be
appropriate.
Because PCE is a denser-than-water contaminant (1.63 g/cmr) and is only partially
soluble in water (150 mg/1), it tends to sink within the aquifer. Given the levels of PCE detected
downgradient of OK Tool (>20,000 ug/l), it is likely that PCE exists in the aquifer below OK
Tool as a dense non-aqueous phase liquid (DNAPL). It is also possible that DNAPL sources
exist elsewhere within the area where high VOC concentrations have been defined, i.e.. in the
aquifer below the Hitchiner facility and in the vicinity of MW-20. Potential additional source
areas are further discussed below. Current research and experience at other sites indicates
2176-150/HAZ/5148 4-37
that DNAPLs typically exist as discontinuous accumulations both within the unconsolidated
aquifer and within fractured bedrock below. It is difficult to prove directly the existence of
DNAPLs, and impractical to delineate the location and extent of individual DNAPL
accumulations due to the difficulty in intercepting and sampling these accumulations.
Regardless of the existence of DNAPLs, the high levels of groundwater contamination indicate
that continued long-term migration of contaminants into downgradient portions of the aquifer ,,- 7" ~ ~ ——-i i i i.i. i n . i — — . . . i - ..,.,,.11.i , ,_ ,, „„_.,„.,.,.,„„ „ , , „ m ._.._ „ , ,—. \^
will occur. Cleanup and control of the groundwater in this area will be evaluated as an integral
component of the remedial alternatives for the site. >-^
TCA contamination exhibits some significantly different characteristics of occurrence and C£^ /
distribution from PCE and the related compounds discussed above. The highest detected
concentration of TCA was 1,300 ug/1 at monitoring well MI-30, located downgradient from the
Hitchiner Facility. TCA was detected most frequently in wells on the south side of Elm Street,
adjacent to and downgradient from the Hitchiner Facility. TCA was detected less frequently, but
in concentrations up to 300 ug/1, in wells immediately downgradient from the OK Tool Facility.
It is apparent that the principal source of TCA contamination in groundwater at the site was
associated with the Hitchiner facility.
TCA has been historically used at Hitchiner and is still currently being used. TCA is also
used by Hendrix Wire and Cable and was formerly used by New England Steel Fabricators, as
documented in the 1985 NHWSPCC report, and low levels of TCA have been detected in
groundwater samples collected at NESFAB prior to the RI. It should be noted, however, that
TCA was detected in two wells at NESFAB in a 1983 sampling round but was not detected in a
1984 sampling round of the same wells. Furthermore, the results of groundwater sampling
completed during the RI does not indicate sources of TCA contamination in the vicinity of the
Hendrix or NESFAB facilities. TCA has been detected consistently in water and sediment
samples from permitted process water outfalls at the Hitchiner facility and in the
Hitchiner-Hendrix discharge stream immediately downgradient from the Hitchiner facility.
Specific potential sources within the Hitchiner Facility include the process water dischargeA.
system and the dry well formerly located in a photographic lab within the building. Historical
and current sampling data also-^uggest a TCA source at OK Tool, possibly related to the PCE
source(s) previously discusseor-The data shows this source to be an order of magnitude smaller**
than the source associated with the Hitchiner facility.
2176-150/HAZ/5148 4-38
Given the varied industrial and commercial history of the site area (see Section 1.0) and
the highly permeable nature of the aquifer underlying the site area, it is likely that additional
source -jjKias contribute or have previously contributed to the VOC groundwater contamination at
the sire^rA number of potential additional source areas exist in the site area and it is possible that
other DNAPL sources exist in these areas. The distribution of PCE in groundwater indicates an
apparent anomaly of relatively elevated levels within the plume in the vicinity of the Drive-In
access road (i.e., between wells MW-17 and MW-20), which potentially indicates an additional
source(s) located between OK Tool and the Drive-In road. Past and present operations in this
area include the Hendrix facility, Body Magic Autobody (formerly Talarico Pontiac), the trailer
park and leach field, and a former paving company operation. Additionally, the
Hitchiner-Hendrix discharge stream exits from a culverted section just west of the Drive-In road
prior to crossing under the road and flowing eastward.
As a secondary issue, the data indicates a separate source for methyl-t-butylether (MTBE),
which has been detected in wells MW-6, MW-8, MW-17, MW-18, and MW-19 (see Figure 4-1)
at concentrations ranging from 13 to 60 ug/1.
The distribution of MTBE detected in groundwater at the site suggests that it is derived
from a source located upgradient of the Hitchiner facility (i.e., further west along Elm Street).
MTBE is a common additive in unleaded gasoline and is typically found as a contaminant in
groundwater as the result of gasoline spills or leaking underground storage tanks.
Volatile Organic Compounds - Mass Calculations
The mass of total volatile organic compounds in the plume was calculated by estimating
the volume of groundwater within the 1000 ppb total VOC contour and multiplying that by the
average concentration within that contour. The same procedure was taken for the area between
the 1000 ppb and the 100 ppb contour and the area between the 100 ppb and the 10 ppb contour.
Using an average saturated thickness of 84 feet, an area of 2.38 x 10+6 square feet and an
effective porosity of 0.35, the volume of contaminated groundwater within the 1000 ppb contour
is calculated to be 5.23 x 10+8 gallons (1.98 x 10+9 liters). The average concentration of total
VOCs in the groundwater within the 1000 ppb contour is calculated to be 8.82 x 10+6 grams or
19,448 pounds. Using an average density for trichloroethylene (TCE), tetrachloroethylene
(PCE), and 1,1,1-trichloroethane (TCA) of 1480 grams/liter, this mass corresponds to 5959 liters
or 29, 55 gallon drums of equivalent DNAPL.
2176-150/HAZ/5148 4-39
on Figure 5-3 and the three flow diagrams are included as Figures 5-4 through 5-6. Also
included on Figure 5-3 is groundwater elevation data collected by NHDES on May 3, 1990, at 20
piezometer and well locations along the north side of the river to the west of the plume discharge
area. Specifications for piezometers and wells are provided in Table 2-5.
As illustrated by Figure 5-3, groundwater flows in a generally northeasterly direction from
the site toward the Souhegan River and in a southerly direction from the area of the Milford Fish
Hatchery toward the river. Groundwater flow lines constructed from the data also indicate flow
across the river from the area of the plume (i.e., in from MW-24 to MW-14), eastward flow
along an area bounded by the river and Purgatory Brook, and in the easternmost portion of the
site, flow in a soudieasterly direction along the course of the river. Vertical gradients along the
river are predominantly upward, indicating an up welling and recharge of groundwater to the
river, or more accurately, to a recharge zone broader than but parallel to the river, encompassing
both the river and Purgatory Brook. The direction of vertical gradients observed during this
round of measurements were generally consistent with these observed during previous
measurements in February, 1990, (see Table 3-8). Vertical gradients are anomalously downward
at MW-22, which is located directly across the river from production wells at the private fish
hatchery. The vertical components of groundwater flow in the vicinity of the river and the
nature of the discharge zone are further illustrated by Figures 5-4 through 5-6. As illustrated by
Figure 5-6, the downward gradient at MW-22 appears to be the result of the influence of
production wells to the north of the river which are inducing the flow of groundwater beneath
the river. Based on this hydraulic gradient data, the production wells may be drawing low levels
of contaminants from the south side of the river in the area of MW-22.
The detection of VOC contaminants in die groundwater at the State Fish Hatchery
observation wells FH-22, FH-25 and FH-27, located on the north side of the river between the
river and Purgatory Brook, is consistent with the expected route of plume migration based on the
hydraulic data discussed above. The detection of VOCs in wells FH-28, 29 and 30 at the private
fish hatchery, may also be the result of migration along this pathway.
The December. 1990 sampling of MW-34 detected 9 ug/1 of PCE. thus the conclusion may
be mat both directions of groundwater flow are contributing to the contaminants at the private
fish hatchery wells.
As illustrated by the groundwater contour map (Figure 5-3) and the cross-sections (Figures
5-4 through 5-6), the hydraulic gradients and bedrock topography immediately north of the fish
hatchery wells are relatively steeply sloping to the south, such that groundwater flow is to the
south from North River Road toward die fish hatchery wells. Therefore, it appears that further
migration of contaminants to the north of die current extent is unlikely.
2176-150/HAZ-5149 5-13
The bedrock surface also slopes upward to the east of the Souhegan River (see also Plate
V, Bedrock Contour Map), outcropping near P-13 and intercepted by MW-15 at approximately
15 feet below the ground surface. Groundwater is thus constrained to flow in a southeasterly
direction along and discharging to the Souhegan River, such that migration of VOC
contaminants to the east beyond the river appears unlikely. The continued migration of
contamination will likely be underneath and in the same direction of the River further down the
valley.
As previously discussed, sampling of surface water and sediments in the Souhegan River
along the discharge zone has not indicated that the contaminant plume has impacted the river
and it appears that the low levels of VOCs in groundwater discharging to the River are further
diluted upon discharge to levels below detection limits. There is no assurance that the discharge
of contaminants will remain below detection limits.
Groundwater/Contaminant Flux to the Souhegan River
Hydraulic gradient data, as previously discussed, indicate that groundwater from the site
flows toward and discharges to the Souhegan River along the river reach extending from
somewhere between SG-2 and SG-3 to WLR-5.
Estimations of groundwater and contaminant flux to the river were performed based on:
1) contaminant mass calculations; 2) flow net analysis; 3) groundwater flux calculations using
average saturated aquifer thicknesses, widths, and hydraulic gradients for individual slreamrubes
and the hydraulic conductivity as estimated from pump tests; and 4) average total VOC
concentrations along the streamtubes.
The mass of total volatile organic compounds in the plume was calculated by estimating
the volume of groundwater within the 1000 ppb total VOC contour and multiplying that by the
average concentration within that contour. The same procedure was taken for the area between
the 1000 ppb and the 100 ppb contour and the area between the 100 ppb and the 10 ppb contour.
Using an average saturated thickness of 84 feet, an area of 2.38 x 10+6 square feet and an
effective porosity of 0.35, the volume of contaminated groundwater within the 1000 ppb contour
is calculated to be 5.23 x 10+8 gallons (1.98 x 10+9 liters). The average concentration of total
VOC's within this contour is 4453 x 10-6 grams/liter. The mass of VOC's in the groundwater
within the 1000 ppb contour is calculated to be 8.82 x 10+6 grams or 19.448 pounds. Using an
average density for trichloroethylene (TCE), tetrachloroethylene (PCE), and 1,1,1
trichloroethane (TCA) of 1480 grams/liter, this mass corresponds to 5959 liters or 29 55-gallon
drums of equivalent DNAPL.
2176-150/HAZ-5149 5-18
Hydraulic gradient data indicated that the ground water from the site flows toward and
discharges to the Souhegan River along the reach extending from somewhere between SG-2 and ^_
SG-3 to WLR-5. Based on hydraulic gradient data, it appears that there is also limited flow ofC ?/
groundwater from the site to the north side of the river in the vicinity of the private fish hatchery,
which may be uxpart due to induced flow from production wells at the private fish hatchery.
Thus, the results of the RI indicate that the principal potential receptors at the site are the
Souhegan River and the private fish hatchery wells. However, the results of the RI have not
indicated the presence of VOCs in the Souhegan River and PCE has been detected in the fish
hatchery wells only at the 1 to 4 ug/1 level, below the MCI and the ambient water quality criteria.
Table 5-2 gives a summary of the extent of the volatile groundwater contamination by
volatile, organic compounds at the site and of water balance and groundwater/contaminant flux
datsfc-^Fne natural flux of contaminated groundwater has been estimated to be 432 gallons per
minute or 227 million gallons per year, and the flux of equivalent DNAPL is 147 gallons per
year. Assuming that all of the contaminated groundwater discharges to the Souhegan River, 147
gallons per year of equivalent DNAPL would be diluted by an average of 171 cfs or 40 billion
gallons per year of river water.
The aquifer is currently producing groundwater from production wells used by industry
and by fish hatcheries to the north of the river. Significant current pumping within the
contaminated portion of the aquifer is limited to the Hitchiner production well, pumping at a rate
of 250 to 270 gpm. Historic pumping within the contaminated aquifer included the Savage Well
(430 to 570 gpm) and the Hendrix Production Well (104 to 156 gpm).
Existing and past pumping at the Hitchiner, Hendrix, and Savage Wells removed from 784
to 996 gallons per minute or an average of 468 million gallons per year of contaminated
groundwater. The estimated amount of equivalent DNAPL removed as a result of this pumping
is 111 gallons per year. (3 3
2176-150/HAZ-5149 5-23
excavation at the easternmost edge of the building, had PCE at a level of 900 ug/kg.
Trichloroethylene (TCE) was detected at 19 ug/kg in soil sample SL-8. The presence of
methylene chloride, identified in five of the samples, has been determined to be the result of
laboratory contamination.
Two of the soil samples collected from the stockpiles located north of the O.K. Tool
building were found to contain PCE at levels below the detection limit while the third contained
PCE at 44 ug/kg. The sample collected from the storm drain contained PCE at 840 ug/kg, TCE
at 160 ug/kg, and 1,2-DCE at 320 ug/kg.
The four samples collected beneath the Hitchiner facility contained no detectable VOC's
with the exception of Acetone, detected at 22 ug/kg in SL-9.
Sampling of soils beneath the Hendrix building indicated detectable levels of PCE in three
of four samples. PCE was detected at 100 ug/kg in SL-16, collected from a floor drain, at 110
ug/kg in SL-13, and at 5 ug/kg in SL-14.
One sample from each sub-floor area was also analyzed for the complete Hazardous
Substance List (HSL) parameters including acid and base/neutral extractable organic compounds
(ABNs), polychlorinated biphenyls (PCBs), and metals. The results do not appear to indicate a
source for these contaminant parameters at any of the locations.
The results of the additional soils investigation do not appear to indicate the presence of
VOCs in vadose zone soils at levels high enough to serve as a long-term source for groundwater
contamination. CO^.
Metal debris is present in soils at depths of one to five feet below the ground surface
throughout an area measuring approximately 100 feet by 50 feet, located between the northwest
comer of the O.K. Tool building and the Souhegan River. A second area of metal debris exists
along the north side of the nearby state-owned lot, adjacent to the Souhegan River. Laboratory
analyses of soils from test pits and borings in the areas of metal debris indicate comparatively
elevated levels of a number of metals, including arsenic, barium, chromium, copper, iron, lead,
manganese, nickel, and vanadium.
PCBs were detected in soils in the vicinity of the O.K. Tool Building at levels of 0.633 to
3.48 mg/kg, and at a level of 24.0 mg/kg in a soil sample collected adjacent to the
Hitchiner- Hendrix discharge stream.
Surface Water
The detection of VOCs in surface water within the study area was limited to samples
collected from the NPDES-permitted Hitchiner-Hendrix discharge stream. The single exception
2176-150/HAZ-5149 7-2
to this was the detection of low levels of PCE, TCE and 1,2-DCE in the surface water body
directly southwest of the Savage Municipal Well, referred to herein as Savage Pond. The VOCs
detected in Savage Pond are likely derived from the groundwater contaminant plume.
The highest total VOC concentrations, in excess of 400 ug/1, occur in samples collected
from permitted outfalls at the Hitchiner facility (SW-5, which discharges to the ponded area at
the upstream end of the stream) and Hendrix facility (SW-19). VOC concentrations decrease
rapidly downstream from the outfalls. The most prevalent contaminants detected in surface
water along the Hitchiner-Hendrix discharge stream are acetone, TCA and PCE; detected at
maximum concentrations of 300 ug/1, 260 ug/1, and 29 ug/1, respectively.
As summarized in the 1985 NHWSPCC Hydrogeological Investigation, data from
sampling performed at Hitchiner outfalls (including the ponded area) in 1983 and 1984, prior to
the RI, indicated the presence of acetone at concentrations up to 2010 ug/1, TCA at
concentrations up to 1800 ug/1, and PCE at concentrations up to 56 ug/1. Other VOC's
previously detected include 1,1-DCA, 1,1-DCE, 1,2-DCE, TCE, methylethyl ketone, methyl
isobutyl ketone, toluene, and benzene.
Concentrations of individual VOC's were in some instances higher in discharge stream
samples than in the Hitchiner production well, and in some instances lower than in the well.
During the RI, Acetone and TCA have been detected in the upper portion of the discharge
stream (south of Elm Street) and in the lower portion of the discharge stream (stations SW-8 and
SW-9). The source of acetone and TCA detected in surface water appears to be permitted
process water discharges from the Hitchiner facility.
PCE has been detected downstream of the Hendrix outfalls and throughout the length of
the lower discharge stream, but at concentrations less than 20 ug/1. Other VOCs detected in the
Hendrix outfalls included TCA, toluene, benzene, acetone, styrene, acrolein, and MTBE. These
permitted discharges from the Hendrix facility were ceased in March, 1990, when Hendrix
installed a process water recycling system. PCE concentrations detected during the RI in the
Hendrix production well and in MW-8, located immediately upgradient of the Hendrix well,
were comparable and in some cases higher than the concentrations in the Hendrix outfalls prior
to the cessation of discharges. Data compiled by NHWSPCC prior to the RI also indicates
higher PCE concentrations in the production well than in the Hendrix outfall or in the discharge
stream downstream of Hendrix. Therefore, the PCE which was discharged from the Hendrix
facility prior to March, 1990, appears to have been derived from the interception of
2176-150/HAZ-5149 7-3
PCE-contaminated groundwater south of Elm Street by the Hendrix production well. Other
VOCs were in some instances higher in the outfall and the discharge stream and in some
instances lower.
VOCs were detected in stream sediments primarily at locations adjacent to or immediately
downstream of NPDES-permitted process water outfalls from the Hitchiner facility. The
principal VOC contaminants detected in sediments were acetone, TCA and 1,1 -DC A. All are
likely derived from process water discharges from the Hitchiner facility as discussed above in
regard to surface water contaminants. Also detected in sediments near the Hitchiner outfalls
were toluene and chloroethane. Levels of VOCs in sediments drop off rapidly further
downstream from the Hitchiner outfalls. Acetone, PCE and 1,2-DCE were also detected in low
levels in sediments at the Savage Pond, located approximately 100 feet southwest of the Savage
well. TCE and 1,2-DCE detected at this location are likely derived from groundwater recharge
to the pond.Several ABNs were detected in sediments along the upper portion of the discharge stream,
with elevated levels limited to sediments immediately downstream from the Hitchiner outfalls.
Fluoranthene and bis(2-ethylhexyl)phthalate were the most commonly detected compounds and
appear to be derived from discharges from the Hitchiner facility.
A number of ABNs were also detected in sediment samples collected in the Souhegan
River at locations greater than 800 feet upstream of the O.K. Tool property. The source of these
contaminants has not been determined, but is clearly located upstream from the study area.
During the sampling of surface water systems, polychlorinated biphenyls (PCBs) were
detected only in sediments immediately adjacent to the Hitchiner outfalls, at concentrations up
to 6.5 mg./kg.Lastly, a number of metals, including cadmium, chromium, copper, iron, lead, mercury,
nickel, and zinc, were detected at somewhat elevated levels further downstream.
Groundwater
Volatile Organic Compounds
The four principal VOC contaminants detected in groundwater at the site are:
2176-150/HAZ-5149 7-4
• tetrachloroethylene (PCE)
1,1,1 -trichloroethane (TCA)
trichloroethylene (TCE)
1,2-dichlorocthylene (1,2-DCE)
The observed distribution of volatile organic compounds is approximately 6,200 feet long
and approximately 2,500 feet wide, extending from the vicinity of O.K. Tool and Hitchiner
(MI-20, MI-24, MI-26, MI-27 and MI-30) Manufacturing in the west to the Souhegan River in
the east and from Old Wilton Road in the south to the Souhegan River in the north. The highest
concentration of VOCs (22,100 ug/1) was detected in MI-24, immediately to the east of O.K.
Tool, which is screened from 5 to 85 feet in the overburden. Concentrations greater than 1000
ug/1 of total volatile organics were detected at all depths sampled in overburden wells MW-9,
MW-10, MI-7, MI-26, MI-30, MI-32, MW-14, and MW-20. Concentrations of greater than
1000 ug/1 were detected in MW-16 from 40 to 83 feet below ground and in MW-17 from 50 to
95 feet below ground.
Tetrachloroethylene (PCE) is the most widespread and most highly concentrated VOC
contaminant detected in groundwater and mimics the distribution and extent of total volatile
organic compounds (see Figure 1-5). The highest detected concentration of PCE was 18,000
ug/1 at MI-24. Concentrations greater than 1,000 ug/1 occur as far downgradient as MW-14,
approximately 4,000 feet east of O.K. Tool.
The data indicates that the VOC contamination in the overburden is limited to the area
south of the Souhegan River with the exception of MI-67 and MI-68, located on the Milford Fish
Hatchery property, and the private fish hatchery pumping wells (FH-28,29, and 30). Total VOC
concentrations of 582 ug/1 were detected at MI-68, located approximately 50 feet north of the
river and at 17 ug/1 at MI-67, located approximately 250 feet norm of the River. Additionally,
November, 1989, results from NHDES sampling of pumping wells at the private fish hatchery
indicated 1 to 2 ug/1 of PCE in 3 of 5 sampled wells (FH-28, 29, and 30). Sampling performed
by HMM in April, 1990, confirmed these results.
Acid/Base/Neutral Compounds in Groundwater
Only one ABN compound, di-n-butylphthalate, was detected in the monitoring wells
sampled during the Phase n program. This compound was detected in 10 of the 20 wells
sampled, at concentrations ranging from trace to 72 micrograms per liter (ug/1). It is assumed
2176-150/HAZ-5149 7-5
300,000 ug/1), it is apparent that the principal source of PCE contamination in groundwater at the
site was associated with the O.K. Tool facility. Specific sources and potential sources include a
floor drain, an underground tank, and a vapor degreasing tank formerly located inside the
building, an above ground PCE tank located outside the building, and areas outside the building
which were apparently used for the disposal of oily wastes and metallic wastes. Given the
highly permeable nature of the aquifer underlying the site area and the large pumping of /<2>
groundwater from the aquifer which has redistributed the contaminated groundwater, it may not
be possible to delineate specific additional sources of PCE and other VOC sources even though
PCE and other VOCs were historically present at several industries and the distribution of PCE
in groundwater indicates that there may be additional sources at the site.
TCE, 1,2-DCE, and 1,1-DCE exhibit distributions throughout the site that are generally
similar to that of PCE, although these compounds are somewhat less widespread in occurrence,
are less continuously detected throughout the aquifer, and occur at concentrations which are
generally at least an order of magnitude lower than those of PCE. TCE readily forms as a
degradation product of PCE, while 1,2-DCE and 1,1-DCE form as degradation products of both
PCE and TCE. The results of the RI do not indicate any separate primary source areas for TCE,
1,2-DCE, or 1,1-DCE contamination in groundwatefr^These compounds have been detected in
the surface waters of the Hitchiner-Hendrix discharge stream.
Given the known and potential use of PCE-based solvents at other industries and
commercial operations within the site area and the results of the RI, it is possible that additional
sources within the site area contributed to the PCE and related groundwater contamination.
Other potential sources are discussed in more detail at the end of this section.
The sampling results for the soils beneath O.K. Tool, as previously discussed in the soils
section, do not suggest a contaminant source area which warrants source control remedial action
specific to the soils. There are, however, high levels of PCE contamination in groundwater
downgradient from the O.K. Tool facility, which imply the existence of contamination at depths
within the aquifer, beneath die O.K. Tool building, therefore cleanup of the groundwater may be
appropriate.
Because PCE is a denser-than-water contaminant (1.63 g/cnr*) and is only partially
soluble in water (150 mg/1), it tends to sink within the aquifer. Given the levels of PCE detected
downgradient of O.K. Tool (>20,000 ug/1), it is likely that PCE exists in the aquifer below O.K.
2176-150/HAZ-5149 7-7
Tool as a dense non-aqueous phase liquid (DNAPL). It is also possible that DNAPL sources
exist elsewhere within the area where high VOC concentrations have been defined in the aquifer
below the Hitchiner facility and in the vicinity of MW-20. Potential additional source areas are
further discussed below. Current research and experience at other sites indicates that DNAPLs
typically exist as discontinuous accumulations both within the unconsolidated aquifer and within
fractured bedrock below. It is difficult to prove directly the existence of DNAPLs, and
impractical to delineate the location and extent of individual DNAPL accumulations due to the
difficulty in intercepting and sampling these accumulations. Regardless of the existence of
DNAPLs, the high levels of groundwater contamination indicate that continued long-term
migration of contaminants into downgradient portions of the aquifer will occur. '^z^
TCA contamination exhibits some significantly different characteristics of occurrence and
distribution from PCE and the related compounds discussed above. The highest detected
concentration of TCA was 1,300 ug/1 at monitoring well Nfl-30, located downgradient from the
Hitchiner Facility. TCA was detected most frequently in wells on the south side of Elm Street,
adjacent to and downgradient from the Hitchiner Facility. TCA was detected less frequently, but
in concentrations up to 300 ug/1, in wells immediately downgradient from the O.K. Tool
Facility. It is apparent that the principal source of TCA contamination in groundwater at the site
was associated with the_Hitchiner Facility.
TCA has been historically used at Hitchiner and is still currently being used. TCA is also
used by Hendrix Wire and Cable and was formerly used by New England Steel Fabricators, as
documented in the 1985 NHWSPCC report, and lew levels of TCA have been detected in
groundwater samples collected at NESFAB prior to the RI. It should be noted, however, that
TCA was detected in two wells at NESFAB in a 1983 sampling round but was not detected in a
1984 sampling round of the same wells. While the results of groundwater sampling completed
during the RI does not indicate a source of TCA contamination either at the Hendrix or NESFAB
facilities, both companies have used TCA in the past. In the case of NESFAB, historical
sampling indicates a source of TCA as well as other chemicals. In addition, given the highly,
permeable nature of the aquifer underlying the site area and the large volume and long-term
pumping (which is equivalent to induced flushing) of groundwater, it may not be possible to
delineate specific sources of chemicals at these facilities. TCA has been detected consistently in
water and sediment samples from permitted process water outfalls at the Hitchiner facility and in
the Hitchiner-Hendrix discharge stream immediately downgradient from the Hitchiner facility.
For these reasons, it appears that a principal source of TCA contamination in groundwater was
2176-150/HAZ-5149 7-8
located at the Hitchiner Facility. Specific potential sources within the Hitchiner Facility include
the process water discharge system and the dry well, formerly used in a photographic lab within
the building, which was removed in 1985 during the excavation for the east building addition.
Historical and current sampling data also suggest a TCA source at O.K. Tool, possibly related to
the PCE source(s) previously discussed. Both 1,1-DCE and 1,1-DCA, also detected at the site,
may form as degradation products of 1,1,1 TCA and are likely derived from a common source.
Given the varied industrial and commercial history of the site area (see Section 1.0) and
the highly permeable nature of the aquifer underlying the site area, it is likely that additional
source areas contribute or have previously contributed to the VOC groundwater contamination at
the site. The RI data have not delineated specific additional sources for the VOCs of concern,
and it may be impossible to do so given the nature of the aquifer and the contaminant plume.
However, a number of potential additional source areas exist in the site area and it is possible
that other DNAPL sources exist in these areas. The distribution of PCE in groundwater
indicates an apparent anomaly of relatively elevated levels within the plume in the vicinity of the
Drive-In access road (i.e., between wells MW-17 and MW-20), which potentially indicates an
additional source(s) located between O.K. Tool and the Drive-In road. Past and present
operations in this area include the Hendrix facility, Body Magic Autobody (formerly Talarico
Pontiac), the trailer park and leach field, and a former paving company operation. Additionally,
the Hitchiner-Hendrix discharge stream exits from a culverted section just west of the Drive-In
road prior to crossing under the road and flowing eastward.
As a secondary issue, several source areas have been indicated for contaminants other than
the principal VOCs of concern.
First, the distribution of MTBE detected in groundwater at the site suggests that it is
derived from a source located upgradient of the Hitchiner facility (i.e., further west along Elm
Street). MTBE is a common additive in unleaded gasoline and is typically found as a
contaminant in groundwater as the result of gasoline spills or leaking underground storage tanks.
Secondly, a number of ABNs were also detected in sediments at the upstream end of the
Souhegan River. The source of these contaminants has not been determined, but is clearly
located upstream from the study area.
Lastly, at wells MW-21A, 21B and 21C, located adjacent to the Medlyn Motors
automobile dealership and garage, emulsions of what appeared to be waste oil or weathered fuel
oil were observed in drilling fluids. An oil sheen was observed in water during development of
2176-150/HAZr5149 7-9
the wells and during purging of the wells prior to the July, 1989, sampling round; however, the
amount of product in the wells appeared to be negligible. During the April, 1990, sampling
round, the wells were gauged for the presence of free product and the amount of product in the
wells was again observed to be negligible.
7.1.2 Fa^ and Transport
The Savage Well Site is located within an extensive sand and gravel aquifer, a portion of
which is contaminated with volatile organic compounds (VOCs) consisting primarily of PCE,
TCE,TCA,andl,2-DCE.VOC contaminants are the principal concern at the Savage Well Site in terms of potential
for migration and potential for exposures which could impact human health, as well as in the
terms of development, evaluation, and design of remedial alternatives. Groundwater and surface
water are considered the primary pathways for migration offsite. The ABN, PCB, and metal
contaminants detected at the site have limited mobility in the environment and limited potential
for migration to exposure points.The observed distribution of VOC contaminants in groundwater is generally consistent
with the observed patterns of regional groundwater flow as modified by historic pumping
patterns. VOC contaminants appear to have migrated in an easterly direction, from source areas
in the vicinity of the OK Tool building and the Hitchiner and Hendrix facilities along the south
side of Elm Street, through the area of wells MW-9, MW-10 and MW-17, which is also the
location of a bedrock trough feature, and subsequently in a northeasterly dkection towards the
Savage Well and the Souhegan River.Rates of groundwater flow across the site were determined using calculated hydraulic
conductivity values from falling head tests, sieve analysis, the pump test of the Savage Well, and
the pump test of the Hitchiner Production Well, an assumed effective porosity of .2 to .35 and
observed hydraulic gradients (see Section 3.4.1). The calculated flow rates were used to
estimate travel times for groundwater flow between the OK Tool facility, the Savage Well, and
the Souhegan River, along a pathway coincident with the center of the contaminant plume.
Based on an average hydraulic conductivity of 49 feet/day obtained from falling head tests
and sieve analyses, the estimated time of travel from OK Tool to the Savage Well ranged from
approximately 15 to 25 years, and the estimated time of travel from OK Tool to the Souhegan
River ranged from 20 to 33 years. Based on the hydraulic conductivity of 235 feet per day
obtained from the pump test of the Hitchiner production well, the estimated travel times ranged
from approximately 3 to 5 years and 4 to 7 years, respectively.
2176-150/HAZ-5149 7-10
The overall trend of eastward migration of contaminants and eventual discharge to the
Souhegan River are consistent with the currently mapped regional groundwater flow pattern.
Historic pumping from industrial and fish hatchery wells has broadened the plume substantially
as the plume follows the regional groundwater flow to the east. In addition, bedrock topography
and surface water discharge and recharge, and contributions from various source areas have
further affected the pattern of contaminant distribution in groundwater.
Hydraulic gradient data indicated that the groundwater from the site flows toward and
discharges to the Souhegan River long the reach extending from somewhere between SG-2 and
SG-3 to WCR-5. Groundwater also continues to flow downgradient along the river valley. Thus
contamination that reaches the eastern portion of the existing site area will eventually move
offsite further to the east. Based on hydraulic gradient data, it appears that there is also limited
flow of groundwater from the site to the north side of the river in the vicinity of the private fish
hatchery, which may be in part due to induced flow from production wells at the private fish
hatchery.
Thus, the results of the RI indicate that the principal potential receptors at the site are the
Souhegan River and the private fish hatchery wells. However, The results of the RI have not
indicated the presence of VOCs in the Souhegan River and PCE has been detected in the fish
hatchery wells only at the 1 to 4 ug/1 level, below the MO and the ambient water quality criteria.
Table 5-2 gives a summary of the extent of the volatile groundwater contamination by
volatile organic compounds at the site and of water balance and groundwater/contaminant flux
data>~Fne natural flux of contaminated groundwater has been estimated to be 432 gallons per
minute or 227 million gallons per year, and the flux of equivalent DNAPL is 147 gallons per
year. Assuming that all of the contaminated groundwater discharges to the Souhegan River, 147
gallons per year of equivalent DNAPL would be diluted by an average of 171 cfs or 40 billion
gallons per year of river water.
The aquifer is currently producing groundwater from production wells used by industry
and by fish hatcheries to the north of the river. Significant current pumping within the
contaminated portion of the aquifer is limited to the Hitchiner production well, pumping at a rate
of 250 to 270 gpm. Historic pumping within the contaminated aquifer included the Savage Well
(430 to 570 gptn) and the Hendrix Production Well (104 to 156 gpm).
Existing and past pumping at the Hitchiner, Hendrix, and Savage Wells removed from 784
to 9% gallons per minute or an average of 468 million gallons per year of contaminated
groundwater. The estimated amount of equivalent DNAPL removed as a result of this pumping
2176-150/HAZ-5149 7-11
is 111 gallons per year. The estimated amount cannot be considered reliable due to the
variability of assumptions that can be made as to the concentrations of the contamination in the
groundwater that was pumped.
Contamination has been found in the bedrock aquifer at several locations. Continued
migration of contamination in bedrock may impact households that obtain drinking water from
the bedrock aquifer. All but two of the houses north of the river within the study area obtain
their drinking water from bedrock wells. The sampling data to date indicates that none of the
household wells have VOC contaminants at present.
7.1.3 Risk Assessment
The Baseline Health Risk Assessment portion of the RI was prepared by
Buonicore-Cashman Associates and submitted to EPA as a separate document on October 31,
1989. The objective of the Risk Assessment was to determine the extent to which the site
conditions, as delineated by the Remedial Investigation, may impact human health, welfare, or
the environment. The Risk Assessment consisted of the following general components.
• Hazard identification and selection of constituents of concern
• Toxic ity (dose-response) assessment
• Exposure assessment
• Risk characterization
Constituents of concern were selected for the various media (groundwater, surface water,
soil and sediment, and air) based on toxic ity, mobility, persistence in the environment,
concentration, and frequency of detection. For groundwater, the following constituents were
selected.
• Tetrachloroethylene
• Trichloroethylene
• 1,2-Dichloroethylene
• 1,1,1 -Trichloroethane
• 1,1-Dichloroethylene
• 1,1-Dichloroethane
2176-150/HAZ-5149 7-12
• Arsenic
• Beryllium• Chromium
' Uad
Nickel
For surface water, the selected constituents of concern were:
• Acetone• 1,1,1-Trichloroethane
• Tetrachloroethylene
• Benzene
• Styrene• 1 , 1 -Dichloroethane
Arsenic /-<3\. \J~ -*j• Chromium
• Lead
Nickel
For soils and sediments, the following compounds were selected:
• Acetone• Carbon tetrachloride
1,1 -DichloroethaneMethylene chlorideTetrachloroethylene1,1,1 -Trichloroethane (z '-OToluene
• Arsenic
• Cadmium• Chromium• Lead• Mercury
Nickel• Beryllium
PCBs
2176-150/HAZ-5149 7-13
For air, the following compounds were selected:
• Acetone
• Methylene Chloride
• Tetrachloroethylene
1,1,1-Trichloroethane
Five exposure scenarios were analyzed that apply to the present use of the property^
(contact with water and sediment in the trailer park stream north of Elm Street, worker contact
with soils or sediment at the Hitchiner and Hendrix area south of Elm Street, contact with
surface materials at the OK Tool Facility, inhalation of volatiles in ambient air). Of these
potential exposures, exposure to surface water and sediment appears to pose moderate risk (6 x
10" risk and hazard index below 1 for maximum exposure), as does the worker contact scenario
at the Hitchiner and Hendrix facilities (4 x 10*^ risk and hazard index below 1; and 2 x 10~5 and
hazard index below one for maximum exposure to sediment or soil, respectively) as it is at the
lower end of the risk range specified by EPA in establishing cleanup goals. A very low to
moderate risk, and the widest range in estimated risks is associated with chronic exposure to
VOC in ambient air (7 x 10~6, hazard index below 1). This exposure is associated with perhaps
the greatest uncertainty. A moderate risk (3 x 10"5, hazard quotient of 2.9 for lead) is associated
with soil contact at the OK Tool facility.It should also be remembered that an initial analysis of chemicals detected in production
wells at the commercial fish hatchery indicated low impact at this time, but continued
monitoring was suggested.Five exposure scenarios apply to potential future uses at the site (ingestion of
groundwater, irrigation with groundwater, residential-type use of the Hitchiner and Hendrix
(sediment and soil) and OK Tool properties). High risk is associated with chronic ingestion of
water-it is clear that the groundwater at much of the site is not suitable for continual
consumption in its present condition. A municipal system currently supplies drinking water to
the area south of the Souhegan River. Residences north of the river obtain their drinking water
from bedrock wells (with the exception of two homes that have shallow wells). No residences
north of the river that were tested had VOC contamination but continued monitoring is
recommended. Low risk was associated with the irrigation exposure scenario (risk of 2 x 10" ,
hazard index below 1).Moderate to high risk relative to target risks was estimated for potential future use of the
Hitchiner and Hendrix and OK Tool facilities for residential-type frequent contact scenarios
2176-150/HAZ-5149 7-14
(risk levels of 1 x 10" and 1 x 10"4 for maximum exposures to sediment and soil, respectively
at Hitchiner and Hendrix and maximum risk of 2 x KT4 at OK Tool), although the probability ofsuch exposures occurring may be low. A hazard index of 21 is associated with soil contact at
OK Tool.
7.2 CONCLUSIONS
7.2.1 Data Limitations and Recommendations for Future Work
In order to provide additional data on site characterization and contaminant
characterization relevant to the development and evaluation of remedial alternatives at theSavage Well site, the following additional field investigation activities are recommended and/or
were completed subsequent to the RI:
• Due to the detection of acetophenone in surface water, a subsequent groundwatersampling round completed in December, 1990 included analysis for acetophenone.The results did not indicate the presence of acetophenone in groundwater, however,limited sampling for acetophenone was done during the RI and the data may be t inconclusive as to its presence in groundwater. The complete results will be
included as an appendix to the RI.
The RI data suggest that residual VOC contamination may exist as free phaseDNAPL (dense non-aqueous phase liquid) at depth in the overburden aquifer in thevicinity of MW-17, MW-18 and MW-20. During remedial design, additionalmonitoring should be undertaken to determine whether free phase DNAPL exists,
and the overall dimensions of this area.
• The monitoring of household bedrock wells north of the river should be undertakenon a periodic (minimum yearly) basis to insure the protection of human healthfrom the migration of VOC contamination in the bedrock aquifer.
/"~i==N• The monitoring of selected overburden wells should be done on a periodic basis to w •] i
insure the protection of environmental receptors at the fish hatcheries.
2176-150/HAZ-5149 7-15
7.2.2 Recommended Remedial Action Objectives
Contaminants have been detected at the Savage Well Site in groundwater, surface water,
sediments, and soils. The overall purpose of remediating the site is to reduce the risks to the
public health and welfare and to the environment.
Standards for site remediation are provided by CERCLA as amended by the Superfuhd
Amendments and Reauthorization Act (SARA). The preamble to the National Contingency Plan
(NCP) includes a summary of federal and state statutes, regulations, advisories, etc. that are
potentially applicable or relevant and appropriate requirements (ARARs) for remedial
alternatives. ^^,
Described below are the specific objectives that the remedial alternatives currently being
developed in the Feasibility Study should satisfy. The discussion is organized into objectives for
source control and for management of migration alternatives.
Source Control Objectives
The remedial response objectives for source control measures include:
1. Reduce risks to human health from direct contact with contaminants in soils and
sediments;
2. Contain the hazardous substances, pollutants, and contaminants thereby reducing
migration to surface water bodies and groundwater aquifers; and
3. Employ treatment/destruction to reduce or eliminate mobility, toxicity and volume
of hazardous substances, pollutants or contaminants.
Source areas under evaluation include the soils in the vicinity of the O.K. Tool building,
the state-owned land, the Hitchiner facility, and the Hendrix facility, and sediments in the
Hitchiner-Hendrix discharge stream.
Management of Migration Objectives
The remedial response objectives for management of migration measures are to reduce the
risks associated with present and future uses of groundwater. They include:
2176-150/HAZ-5149 7-16
1. Restore the groundwater to MCLs or to contaminant levels which are protective of
the public health and the environment;
2. Prevent or mitigate the migration of contaminants above levels protective of public
health and the environment; and
3. Comply with Federal and State ARARs.
2176-150/HAZ-5149 7-17
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Adamus. P. R., Clairin, E. J., Jr. Smith, R. D. and Young, R. E. 1987. Wetland EvaluationTechnique; Vol H: Methodology, Operational Draft Technical Report Y-87-_, US ArmyEng. Waterways Experiment Station, Vicksburg, Miss.
AJeinikoff, John-N., 1978. Structure, Petrology, and U-Th-86 Geochronology in the Milford(15') Quadrangle, New Hampshire. Masters Thesis .Dartmouth College.
American Society for Testing and Materials (ASTM), 1987.C 150, Specifications for Portland CementC 778, Specifications for Standard SandD 1452, Practice Method for Soil Investigation and Sampling by Auger Borings.D 1586, Method for Penetration Test and Split Barrel Sampling of Soils.D 1587, Practice for Thin-Walled Tube Sampling of Soils.D 1785 Specifications for Poly Vinyl Chloride (PVC) Plastic Pipe, Schedules 40, 80,
and 120.D 21 13, Practice for Diamond Core Drilling for Site Investigation.D 2487, Test Method for Classification of Soils for Engineering Purposes.D 421, Practice for Dry Preparation of Soil Samples for Particle - Size Analysis and
Determination of Soil Constants.D 653, Terms and Symbols Relating to Soil and Rock.D 2488, Practice for Description and Identification of Soils (Visual-Manual Procedure).D 4448, Guide for Sampling Groundwater Monitoring Wells.
Anderson-Nichols & Company, Inc., 1981. Water Well Report, Town of Milford, May 1981.
Billings, M. P., 1952. The Geology of New Hampshire, Part n Bedrock Geology. NewHampshire Department of Resources and Economic Development.
D.L. Maher Co., 1985. Groundwater Exploration Investigation at the Milford Fish Hatchery,Milford, NH.
D.L. Maher Co., 1988. Construction Report for Well No. 5, Milford Fish Hatchery, Milford, NH.
Environmental Science & Engineering, Inc., July, 1990. Baseline Health Risk Assessment,Savage Well MPL Site, Milford, New Hampshire.
Greene, R. C., 1970. Geology of Peterborough Quadrangle Bulletin 4, New HampshireDepartment of Resources and Economic Development.
HMM Corporate Health and Safety Manual, April 1987.
Hussey, A. M. and Newbury, D. W., 1978. Major Faulting in Merrimack Synclororium betweenHollis, New Hampshire and Biddeford, Maine, Geological Society of America Abstract,V. 10, p. 48.
Koteff, C., 1970. Surficial Geologic Map of the Milford Quadrangle, Hillsborough County, NewHampshire. United States Geological Survey, Department of Interior.
Lyons, J. B., 1982. Avalonian and Gander Zones in Central Eastern New England, GeologicalAssociation of Canada, Special Paper 24.
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