COVER SHEET

Name of Site: Milford Contaminated Aquifer

EPA ID No.: OHSFN0507973 

United States Environmental Protection Agency (EPA), Region V: 

Contact Person

Patrick Hamblin

77 West Jackson Boulevard, Mail Code: SR-6J 

Chicago, Illinois 60604 

312-886-6312 

Site Investigation: Jon R. Watterworth

Ohio Environmental Protection Agency 

Division of Emergency and Remedial Response 

401 East Fifth Street 

Dayton, Ohio 45402-2911 

(937) 285-6062 (direct) 

The surface water, soil exposure and air migration pathways are not scored as part of this Hazard Ranking 

System (HRS) evaluation. The surface water migration, soil exposure, and air migration pathways were 

not included because a release or potential release to these media does not significantly affect the overall 

site score and because the ground water migration pathway produces an overall site score above the 

minimum required for the site to qualify for inclusion on the National Priorities List (NPL). 

Pathways, Components or Threat Not Scored
1

HRS DOCUMENTATION RECORD

Name of Site: Milford Contaminated Aquifer 

Date Prepared: October 2010 

EPA Region: V 

Street Address*: 101 Race Street

City, County, State, Zip Code: Milford, Clermont, Ohio, 45150 (Figure 1) (Ref. 3, p. 1) 

General Location in State: Southwestern corner of Ohio in the City of Milford along the eastern 

bank of the Little Miami River (Ref. 3, p. 1) 

Topographic Map: U.S. Geological Survey 7.5-Minute Series Topographic Map of Madeira, 

Ohio, Quadrangle, 1996 (Ref. 3, p. 1) 

Latitude: 39○

 10’ 40.13” North (Ref. 3, p. 1; Ref. 4, p. 1) 

Longitude: 84○

 17’ 37.63” West (Ref. 3, p. 1; Ref. 4, p. 1) 

The latitude and longitude listed above mark the approximate location of the Milford Contaminated 

Aquifer site, specifically the City of Milford well field (Ref. 4, pp. 1, 2). 

* The street address, coordinates, and contaminant locations presented in this HRS documentation record 

identify the general area the site is located. They represent one or more locations EPA considers to be 

part of the site based on the screening information EPA used to evaluate the site for NPL listing. EPA 

lists national priorities among the known “releases or threatened releases” of hazardous substances; thus, 

the focus is on the release, not precisely delineated boundaries. A site is defined as where a hazardous 

substance has been “deposited, stored, placed, or otherwise come to be located.” Generally, HRS scoring 

and the subsequent listing of a release merely represent the initial determination that a certain area may 

need to be addressed under the Comprehensive Environmental Response, Compensation, and Liability 

Act (CERCLA). Accordingly, EPA contemplates that the preliminary description of facility boundaries 

at the time of scoring will be refined as more information is developed as to where the contamination has 

come to be located. 

Scores

Ground Water Migration Pathway - 100.00 

Surface Water Migration Pathway - Not Scored

Soil Exposure Pathway - Not Scored

Air Pathway - Not Scored

HRS SITE SCORE 50.00 
2

WORKSHEET FOR COMPUTING HRS SITE SCORE

 S S2

1. Ground Water Migration Pathway Score (Sgw) 

 (from Table 3-1, line 13) 100 10,000

2a. Surface Water Overland/Flood Migration Component 

 (from Table 4-1, line 30) NS ---

2b Ground Water to Surface Water Migration Component 

 (from Table 4-25, line 28) NS ---

2c. Surface Water Migration Pathway Score (Ssw) 

(enter the larger of lines 2a and 2b as the pathway score) NS ---

3. Soil Exposure Pathway Score (Ss) 

 (from Table 5-1, line 22) NS ---

4. Air Migration Pathway Score (Sa) 

 (from Table 6-1, line 12) NS ---

5. Total of Sgw

2

 + Ssw 2

+ Ss

2 + Sa2 10,000

6. HRS Site Score 

NS – Not Scored

50.00

Divide the value on line 5 by 4 and take the square root.

Note:
3

HRS TABLE 3-1 – GROUND WATER MIGRATION PATHWAY SCORESHEET

MILFORD CONTAMINATED AQUIFER 

Factor Categories and Factors Maximum Value Value Assigned

Likelihood of Release to an Aquifer:

1. Observed Release 550 550

2. Potential to Release:

 2a. Containment 10 NS

 2b. Net Precipitation 10 NS

 2c. Depth to Aquifer 5 NS

 2d. Travel Time 35 NS

 2e. Potential to Release (lines 2a x (2b+ 2c+2d)) 500 NS

3. Likelihood of Release (higher of lines 1 and 2e) 550 550

Waste Characteristics:

4. Toxicity/Mobility (a) 10,000

5. Hazardous Waste Quantity (a) 100

6. Waste Characteristics 100 32

Targets:

7. Nearest Well 50 50

8. Population:

 8a. Level I Concentrations (b) 8,870

 8b. Level II Concentrations (b) 4,404

 8c. Potential Contamination (b) NS

 8d. Population (lines 8a+8b+8c) (b) 13,274

9. Resources 5 0

10. Wellhead Protection Area 20 0

11. Targets (lines 7+8d+9+10) (b) 13,324

Ground Water Migration Score for an Aquifer

12. Aquifer Score [(lines 3X6X11)/82,500] 100 c 100

Ground Water Migration Pathway Score:

13. Pathway Score (Sgw) (highest value from line 12 for 

all aquifers evaluated)

100 c100

Notes:

a. Maximum value applies to waste characteristics category

b. Maximum value not applicable 

c. Do not round to nearest integer

NS - Not Scored 

> 

" 

Notes' 

Concentrations In ugll 

Chlorinated sowents were not 

detected in locations without re5ults 

LEGEND 

TCE TRICHLOROETHENE 

PCE - TETRACHLOROETHENE 

TCA - TRICHLOROETHANE 

t. Phase 1 oca~on5 

... Phase II location, o 25 50 150 200 

--- -- - - Meters 

SOURCE: REFERENCE B, PAGE 1B. Figure 

DCE - DICHLOROETHENE 

EPA. REGION V 

EP-S5-06-1l4 WWj;IJ """""'by. WESTON SOLUTIONS, INC. 

750 E. Bunker Ct. 

SoD Boring Locations 

Milford Contaminated Aquifer 

5 

2 
m 

n 

0' 

u 

o 

'" 

:;;: 

o 

/' 

o 

o 

o 

/'

n 

m 

o 

« 

u 

/.

-0 

LEGEND 


TCE - TRICHLO 


TCA - TRICHLO 


ND - NOT 


NA - NOT ANA 


MTBE - METHY 


BUTYL 


UNITS; ug/L 


SOURCE: REFERENCE 7. PAGE 

NOT TO SCALE 

OETHENE 

OETHANE 

DET CTED 

ZED 

TERTIARY 

ETHER 

GP56 

O ~TCA=3~ 

GP54 

TCA = 4J ®

aPO 

GP44 ® 

NA 

GP53 

TCA:? 

® 

® GP42 

TCA=8 

GP43 

PCE =14 

GP49 

GP50 

TCA '" 3J 

GP51 

TCA = 3J 

® 

® NO 

10; REFERENCE 9B. PAGE 10. 

6 

~~Prepared by: 

WESTON SOLUTIONS, INC. 

750 E. Bunker Ct. 

Vernon Hills IL 60061 

Figure 

Additional Soil Boring Locations 

Milford Contaminated Aquifer 

Milford, Clermont Coun ,Ohio 

3 
Concen trations in ugll 

.., 

.~ .:~ 

, ., , ,," ..~ 

O -= 50 .. 1~OO ==='g ....oj200 • Meters 

.'• 

• Monitori ng well 

SOURCE: REFERENCE 8, PAGE 19. Figure 

LEGEND ....'.......:. Prepared for: Moaitor:la.g Well Locations TeE TRICHLOROETHENE l.iz) u.S. EPA. REGION V peE - TETRACHLOROETHENE WWj;IJ """"'by: TCA - TRICHLOROETHANE t>._~ ContractNo: EP-S5-06-04 WESTON SOLUTIONS, INC. Milfonl Contaminated Aquifer 

DeE - DICHLOROETHENE IDD: S05-1>008-OOO8-021 7S0 E. Bunkec Ct. 

DCN: 762-2A-AIDL VemonHills IL 60061 Milfonl, Clennont Co ,Ohio

7 

4 
....

• 

04 

• 

• 

50' 

o , gend Environmental _ .. ,... . ..... voc Protection Agency G"'und_.. C..........."" 

. . ...... W... 

.....'"".'I""',..""y ,. ""'M_"~••,"",,, ~ -".,"'; ...... M Twl>'l..,.V'._ . .. , ___.......... ",00', 1 ...-.. ... _
 ay 17, 2010 ...._ ,... .""'"_'Io>n .. I_ ........ ....
 JRW C""' ..... , .,.. ..... .-.. uoIng .""...""........... __..lgIooj. 


SOURCE: REFERENCE 10, PAGE 24. Figure

PubHe Supply Well Location. 

EPA. REGION V 

EP-S5-06-1l4 Milford Contaminated Aquifer 

7~O E. BIlIIkcr Ct. 

Ohio 

WESTON SOLUTIONS, INC. 

B 
> 

" N 

" rn 

0 

Sou"", lI.p: USCS 1.5 IUnute Quadranr'. -.. ­.-­..­....­ v 

~w~~ Field 

h 

~ 

.. ,

0 

, 

0 

,

,

• 

N 

rn

, 

" a 

" 0

-:: 

0 

8 

-:: 

" 

e l, ",o,IL.c\lol1 0, 1 ""-1 0 " - 16 0 _ _ (n'IIj W, I 1OCd'" 

SI-ll $ Sol 8or'""i LocGIOn (;q,,* 1.0:011001 ~p'tled "'" of tQUOI <00<",1'01100 £ SOURCE: REFERENCE B, PAGE 47. Figure 

• h~I"'9 moAA"'''''l . .. t.J CIOSS·\ECTnI lot<!01 

,:.""''''1:. Prepared for: Ground Water Plume Map - TetraehJ.oroethene T i.izl u.s. EPA. REGION V q.~ .,..,""""'" _~ Contract No: EP-S5-06-04 I --,l, WESTON SOLUTIONS, Milford Contaminated Aquifer INC. 

rnD: SOS-0008-0908-021 150 E. BunkcI' Ct 

DCN: 762-2A-AHJL VemonHilla IT. 60061 Milfi Clermont Ohio rn 

" 

0 9 u 

-:: 

" 

6 
10

REFERENCES

1. U.S. Environmental Protection Agency (EPA). Hazard Ranking System, Final Rule, Title 40 Code of 

Federal Regulations (CFR), Part 300, 55 Federal Register (FR) 51532. December 14, 1990. 138 pages. A 

complete copy of the Hazard Ranking System can be obtained at the Regional docket upon request.

2. EPA. Superfund Chemical Data Matrix (SCDM), SCDM Data Versions: January 28, 2004 and October 23, 

2006. Excerpt. 8 pages. A complete copy of SCDM is available at 

http://www.epa.gov/superfund/sites/npl/hrsres/tools/scdm.htm. 

3. U.S. Geological Survey (USGS). 7.5-Minute Series Topographic Map: Madeira, Ohio. Scale 1:24,000. 

1996. 1 page.

4. Weston Solutions Inc. (WESTON). Latitude and Longitude Calculations for Milford Contaminated 

Aquifer Site by Brian Coninx, October 19, 2009, 2 pages. 

5. Ohio Environmental Protection Agency (OEPA). Integrated Assessment, Milford Contaminated Aquifer. 

November 14, 2000. 40 pages. 

6. OEPA. Combined Preliminary Assessment/Site Investigation Report, Milford Contaminated Aquifer. 

September 15, 2001. 144 pages. 

7. Tetra Tech EM Inc. Final Report Hydrogeologic Investigation—Milford Wellfield. June 30, 2003. 95 

pages.

8. OEPA. Expanded Site Inspection Report, Milford Contaminated Aquifer, September 19, 2002. 240 

pages.

8A. OEPA. Report On Investigations, Milford Well Field, Clermont County, Ohio, April 26, 1999. 170 

pages.

9. OEPA. Laboratory Data and Field Log Sheets, 2001 PA/SI, Milford Wellfield. July 26, 2010. 167 pages.

9A. OEPA. Expanded Site Inspection Report, Milford Contaminated Aquifer. September 19, 2002. 61 pages.

9B. Reference reserved. 

10. OEPA. Supplemental Expanded Site Inspection Report. March 30, 2010. 450 pages.

10A. OEPA. Soil Gas Survey Information. March 27, 2007. 13 pages.

10B. Ohio Department of Natural Resources and Center for Ground Water Management, Wright State 

University. Ground Water Pollution Potential of Clermont County, Ohio, Report Number 18. October 1994. 

44 pages. 

11. OEPA. Geographic Initiative Report, Milford Wellfield. June 16, 2000. 125 pages. 

11A. Tetra Tech EM, Inc. Hydrogeologic Investigation, Milford Wellfield Site, Milford, Ohio. June 29, 2006. 

263 pages. 

11B. OEPA. Milford Well Field, Sub-Slab Sample Investigation Information. September 28, 2006. 374 pages. 

12. Groundwater Management, Incorporated. City of Milford, Ohio, Hydrogeologic Investigation, November 

4, 1987. 114 pages. 
11

12A. WESTON, Ground Water Contour Maps based on July 10 and July 25, 2002 Ground Water Elevation 

Measurements Performed by M.S. Belfin and Associates, August 2002. 4 pages.

12B. OEPA, Soil Gas Sampling Information. March 27, 2007. 179 pages. 

13. OEPA. Milford Contaminated Aquifer – Public Well Information. February 8, 2010. 9 pages.

13A. Vadose Research Inc. Preliminary Report: Volume I, Soil Gas Contaminant Determination and 

Associated Monitoring Well Sampling, Milford Well Field Area. October 6, 1993. Excerpt. 62 pages.

13B. OEPA. Report on Investigations, Milford Well Field. April 26, 1999. 24 pages. 

13C. University of Idaho. Principles of Environmental Toxicology, Perchloroethylene (PCE) in Dry Cleaning 

Establishments. December 2000. 17 pages. 

14. WESTON. Telephone Conversation Record. Between Lauren Cook, WESTON, and Matthew Newman, 

City of Milford Water Department. November 30, 2009. 3 pages. 

14A. U.S. EPA, Superfund Analytical Services/Contract Laboratory Program (CLP). SOM01.2 Volatile 

Target Compound List and Corresponding CRQLS. Accessed June 29, 2010. 2 pages. Accessed Online at 

http://www.epa.gov/oerrpage/superfund/programs/clp/som-vtarget.htm.

14B. WESTON. Telephone Conversation Record. Between Omprakash Patel, WESTON, and Matthew 

Newman, City of Milford Water Department. July 2, 2010. 1 page. 

15. WESTON. Telephone Conversation Record. Between Lauren Cook, WESTON, and Mark Day, Clermont 

County Water Works Division. December 7, 2009. 2 pages. 

16. WESTON. Telephone Conversation Record. Between Lauren Cook, WESTON, and Customer Service of 

Greater Cincinnati Water Works, Cincinnati, Ohio. December 30, 2009. 2 pages. 

17. U.S. Census Bureau. 2006 through 2008 American Community Survey 3-Year Estimates for Clermont 

County, Ohio, Data Profile Highlights. Accessed February 12, 2010. 2 pages.

http://factfinder.census.gov/servlet/ACSSAFFFacts?_event=Search&geo_id=&_geoContext=&_s

treet=&_county=clermont+county&_cityTown=clermont+county&_state=04000US39&_zip=&_l

ang=en&_sse=on&pctxt=fph&pgsl=010

18. OEPA. Southwest District Office, Milford Well Field. Updated March 2008. Accessed on October 26, 

2009. 1 page. Accessed On-line at

http://www.epa.state.oh.us/swdo/To_be_Deleted/derr_sites/milford_well_field.aspx. 

19. OEPA. Drinking Water State Revolving Fund Wellhead Protection Set-Aside Annual Report, Program 

Year 2008, August 2008. 10 pages. 

20. WESTON. Map Depicting 4-Mile Radius Target Distance Limit. Source of Map: USGS 7.5-Minute 

Series Topographic Quadrangles, Ohio: Madeira, 1996; Withamsville, 1996; Goshen, 1965, Photorevised 

1986. October 16, 2009. 1 page.
12

1.0 SITE DESCRIPTION

The City of Milford is located in western Clermont County, Ohio, approximately 15 miles northeast of 

Cincinnati, Ohio (Refs. 5, p. 3; 6, p. 7). The city obtains its drinking water from a well field consisting of four 

wells drilled in alluvium in the Little Miami River valley (Refs. 10, p. 6;18, p. 1). The well field contains three

wells contaminated with volatile organic compounds (VOCs) (Refs. 7, p. 6; 10, p. 15, 16).

The Milford Contaminated Aquifer site is a ground water plume of chlorinated solvents in the vicinity of Main 

Street and Lila Avenue in the City of Milford, Clermont County, Ohio (Figure 6) (Ref. 8, p. 12). Chlorinated 

solvents detected in ground water at the site include tetrachloroethene (PCE); trichloroethene (TCE); cis-1,2-

dichloroethene (DCE); and 1,1,1-trichloroethane (TCA) (Ref. 8, pp. 9, 10). The area of the ground water 

plume was defined based on ground water samples collected from public wells, monitoring wells, and directpush sampling devices from the unconfined aquifer (Ref. 8, pp. 9, 10, 11, 13, 44, 47). The precise extent of the 

ground water plume and source(s) of ground water contamination have not yet been identified. 

The Ohio Environmental Protection Agency (OEPA) has been the primary agency involved in the 

investigation of this ground water plume. Halogenated solvents were first detected in City of Milford public 

wells (PW)-1 and PW-3 in 1986 (Ref. 8, p. 6). Since then, 1,1,1-TCA and TCE have been detected in PW-3 at 

levels exceeding the maximum contaminant levels (MCL) established under the Safe Drinking Water Act (Ref. 

8, p. 6). TCE concentrations in PW-1 also have exceeded the MCL (Ref. 8, p. 6). In 1987, 1990, and 1991, 

1,1,1-TCA and TCE were detected in PW-2 but at concentrations less than the MCLs (Ref. 8, p. 6). 

OEPA began searching for a source of the VOC contamination in 1991 (Refs. 8, p. 6). OEPA’s contractor, 

Vadose Research, conducted a soil gas survey of the well field area in 1992 (Ref. 8, p. 6). VOCs including 

1,1,1-TCA, 1,1-dichloroethane (1,1-DCA), 1,2-DCE, and 1,1,2-TCA were detected at nine locations (Ref. 8A, 

p. 15). The soil gas survey revealed three potential contaminant source areas, but the results were judged to be 

unreliable because of poor quality assurance (QA)/quality control (QC) results (Refs. 8, p. 6; 8A, p. 23). 

OEPA collected soil samples in 1994 from the potential source areas revealed by the soil gas survey, but no 

VOCs were detected (Refs. 8, p. 6; 8A, p. 18). 

OEPA collected 21 ground water samples in the vicinity of the well field using a direct-push sampling device 

on April 23 through 25 and June 18 and 19, 1996 (Refs. 8, p. 6; 8A, pp. 14, 30). The ground water samples 

were collected from approximately 25 to 50 feet below ground surface (bgs) using plastic tubing with a ball 

check valve (Refs. 8, p. 6; 8A, p.14). Ground water samples could not be collected at many locations because 

of the inability of the direct-push equipment to penetrate the subsurface (Ref. 8A, p.14). Although VOCs were 

detected in samples collected from several areas, a source area was not identified (Refs. 8, p. 7; 8A, p. 23).
13

In April and May, 2000, OEPA conducted a geographic initiative of the Milford well field and OEPA’s 

contractor, PSARA Technology Inc., installed nine wells at five locations in the well field in a semicircle 

starting east and continuing around the south side of the well field (Ref. 11, pp. 7, 13, 22). The new wells were 

installed in pairs, with one well screened at the water table and the other at the bottom of the aquifer (Ref. 8, p. 

7). OEPA collected ground water samples from both the new and existing wells, and results confirmed that the 

aquifer and the well field were contaminated with VOCs (Ref. 8, p. 7). The samples were analyzed for VOCs 

using SW 846 Method 8260B (Ref. 11, p.13). In general, VOC concentrations were higher in the deep wells 

than in the shallow wells (Refs. 8, p. 7; 11, pp. 14, 16). The pattern of detections suggested a possible source 

of 1,1,1-TCA (one of the VOCs detected in the wells) east of the well field (Refs. 8, p. 7; 11, p.18).

OEPA conducted a combined preliminary assessment (PA)/site inspection (SI) in 2001 consisting of the 

installation of three wells east of the well field and the collection of ground water samples from both new and 

existing wells (Refs. 6, pp. 6, 7, 14; 8, p. 7). The samples collected in May 2001 were sent to a CLP laboratory 

for Target Compound List (TCL) VOC analysis (Ref. 6, p.12). The samples collected in August 2001 were 

analyzed for VOCs by mobile laboratory using Method 8260 (Ref. 6, p. 12). The PA/SI confirmed that the 

aquifer and well field were contaminated with VOCs originating from sources east of the well field (Refs. 8, 

p.7; 6, p.21). The pattern of detections suggested that the 1,1,1-TCA source was north of the PCE and TCE 

source (Ref. 8, p. 7; 6, p. 21).

OEPA prepared an expanded site inspection (ESI) work plan dated December 12, 2001 (Ref. 8, p. 5). ESI field 

work was conducted in four phases on March 18 through 22, May 13 through 17, June 6, and July 9, 2002 

(Refs. 8, p. 5; 9A, p. 7). OEPA advanced 36 soil borings, collected 27 ground water samples from the directpush boreholes, and installed and sampled 3 monitoring wells (Refs. 8, p. 5; 9A, pp. 7, 20, 21). The ground 

water samples were submitted to DataChem Laboratories in Cincinnati, Ohio, for rush analysis using U.S. 

Environmental Protection Agency (EPA) Method 8260 (Refs. 8, p.5; 9A, p. 7). PCE was detected in ground 

water samples at concentrations up to 730 μg/L; 1,1,1-TCA was detected at concentrations up to 19 μg/L; 

TCE was detected at concentrations up to 40 μg/L; and cis-1,2-DCE was detected at concentrations up to 40

μg/L (Ref. 9A, pp. 11, 12; Figure 2 of this HRS documentation record). The monitoring well samples were 

analyzed for target compound list VOCs by an EPA contract laboratory (Refs. 8, p. 5; 9A, p. 7). The ESI 

confirmed that the aquifer is contaminated with VOCs from sources east of the well field. The pattern of 

detections suggests that a release of PCE has occurred in the vicinity of a shopping center located 

approximately 3,300 feet east of the well field (Ref. 8, p. 13). 

Ohio EPA conducted a second direct push investigation in 2003 to determine whether VOC contamination 

exists in the vicinity of a Kroger Store located in the area of Service Road, Main Street, and Lila Avenue (Ref. 

7, pp. 8, 9). The Ohio EPA contractor, Tetra Tech EM Inc. completed 18 borings east of Baker Drive between 

Main Street and Lila Avenue (Refs. 7, pp. 9, 10, 16; 10, p. 9). A photoionization detector (PID) was used to 
14

evaluate potential presence of VOCs in soil samples (Ref. 7, p.11). Soil samples were not collected for VOC 

analysis because no elevated PID readings were observed (Ref. 7, p. 11). Ground water samples collected 

were submitted to DataChem Laboratory for VOC analysis by EPA Method 8260b (Ref. 7, p. 12). Low 

concentrations of 1,1,1-TCA and/or PCE were detected in six samples collected from the borings located near 

Lila Avenue and northward to the approximate center of the study area (Ref. 7, p. 16). Results suggested that a 

source of PCE was near Baker Drive (Ref. 10, p. 9). Ground water samples east of Baker Feeds property were 

clean while those on Baker Feed property contained VOCs (Ref. 10, p. 9). 

In April and May 2006, Tetra Tech EM Inc. completed ten soil borings and installed four monitoring wells in 

the Baker Feeds/Baker Party Supply area to further define the suspected source area (Refs. 10, p. 10; 11A, pp. 

10, 11). Monitoring wells MW-17, MW-18, MW-19 and MW-20 were installed during this mobilization 

(Refs. 10, p. 10; 11A, pp. 10, 12). Nine ground water samples and one soil sample were collected from 

borings installed in the study area (Ref. 11A, p. 17). The samples were analyzed for VOCs by Kemron 

Environmental Services using Method 8260A and 8260B (Ref. 11A, p. 17). The direct-push ground water 

sampling revealed levels of PCE in the vicinity of the Baker Feeds store (Ref. 11A, p. 23, Figure 5-1). 

Ohio EPA conducted a State Site Assessment Investigation in 2006 collecting sub-slab soil gas sampling in 

buildings surrounding the suspected source property (Refs. 10, p. 10; 11B, pp. 2-98, 104-109). PCE was 

detected in the sub-slab sample at the Baker Party Store at a concentration of 350 parts per billion volume 

(ppbv) (Refs. 10, p. 10;11B, p. 102). 

An exterior soil gas investigation was conducted by Ohio EPA between the suspected source area and the well 

field in March 2007 (Refs. 10, p. 10; 12B, pp. 2, 12). The soil gas samples were analyzed for VOCs by 

DataChem using Method 8260B (Ref. 12B, pp. 2, 11). PCE was detected at low levels in 4 of 13 soil gas 

samples (Ref. 10A, pp. 2, 3, 5, 9). Additionally, ground water samples were collected from the monitoring 

wells (Ref. 12B, pp. 24-83, 165, 166). 

OEPA prepared a supplemental expanded site inspection (SESI) work plan that was approved by U.S. EPA on 

July 9, 2009 (Ref. 10, p. 6). SESI field work included sampling of 15 monitoring wells; public supply wells; 

and 5 soil samples (including 1 duplicate) for a potential source area identification (Ref. 10, pp. 6, 12, 13, 14, 

15; 23-25). The samples were analyzed for target compound list VOCs by an EPA contract laboratory (Ref. 

10, p. 6). The soil and ground water samples were submitted to Mitkem Laboratories Inc. in Warwick, Rhode 

Island for analysis using CLP SOW SOM01.2 (Ref. 10, pp. 27, 28). The SESI confirmed that the aquifer is 

contaminated with VOCs (Ref.10, p. 6). The soil sampling was not able to identify the source (Ref. 10, p. 18). 

2.2 SOURCE CHARACTERIZATION

2.2.1 Source Identification
15

Source Number: 1

Source Type: Other – Ground water plume with no identified source 

Description and Location of Source (with reference to a map of the site):

Source 1 is a contaminated ground water plume containing the chlorinated solvents PCE; TCE; 1,1,1-TCA; 

and cis-1,2-DCE with no identified source. In accordance with the HRS, the plume itself is considered the 

source (Ref. 1, Sec. 1.1, p. 51587). As currently delineated, the Source 1 ground water plume continues east 

from the City of Milford municipal well field (Figure 6). Despite all the investigations performed to date, the 

ground water contamination cannot be attributed to any source with confidence (Ref. 10, p. 6). The extent of 

this plume has not yet been completely delineated but it has been characterized based on data from soil borings 

(Figures 2 and 3), monitoring wells (Figure 4), and public supply wells and SESI sampling locations (Figure 

5) gathered during various investigations. 

During the 2002 ESI, in order to identify the ground water contamination source(s), OEPA advanced 36 soil 

borings, collected 27 ground water samples from the direct-push boreholes, installed 3 monitoring wells, and 

collected 3 ground water samples from 3 monitoring wells (Refs. 8, p. 5; 9A, pp. 20, 21). 

A possible source of PCE and its degradation products (TCE and cis-1,2-DCE) is located east of the City of 

Milford well field in the commercial business area between Lila Avenue and Main Street (Ref. 8, p. 12). Land 

use in the area primarily consists of mixed residential and commercial uses, with some industrial activity 

interspersed throughout the area (Ref. 7, p. 5). 

During the 2002 ESI, OEPA contractor PSARA Technologies collected ground water samples from directpush borings from March 18 through 22, May 13 through 17, and June 6, 2002 (Refs. 8, p.5, 9; 9A, p.7). 

Results indicated the presence of chlorinated solvents including PCE (maximum concentration of 730 

micrograms per liter [μg/L]); TCE (maximum concentration of 40 μg/L); cis-1,2-DCE (maximum 

concentration of 40 μg/L); and 1,1,1-TCA (maximum concentration of 19 μg/L) (Ref. 8, pp. 9, 10). Ground 

water samples collected by the OEPA contractor from monitoring well MW-14 contained PCE (120 μg/L); 

TCE (7 μg/L); and cis-1,2-DCE (4 μg/L) (Refs, 8, p. 11; 9A, p. 13). 

EnviroCore advanced soil borings MGP40 through MGP57 between June 16 and 23, 2003 (Refs. 7, p. 9, 10, 

16; 10, p. 9). Tetra Tech EM Inc. collected ground water samples from each boring location using dedicated 

polyvinyl chloride (PVC) tubing (Refs. 7, p. 11, 12). The ground water samples were analyzed for VOCs by 

DataChem Laboratories using EPA Method 8260B (Refs. 7, p. 12). Ten of the ground water samples near 

Baker Drive contained low levels of TCA and/or PCE (Ref. 7, pp. 10, 15). 
16

Ground water samples also were collected on May 23, 2001, from PW-1, PW-2, and PW-3 (Ref. 9, p. 41). The 

ground water samples were analyzed for VOCs by American Analytical and Technical Services Inc. using the 

CLP Statement of Work (SOW) OLM04.2 (Ref. 9, pp. 61, 62). PW-3 was found to contain 1,1,1-TCA, DCE, 

and PCE (Ref. 9, pp. 94-98).

OEPA conducted a State Site Assessment Investigation in September 2006 collecting sub-slab soil gas samples

in buildings surrounding the suspected source property (Refs. 10, p. 10; 11B, pp. 2-21, 94-109). PCE was 

detected in the sub-slab sample at the Baker Party Store at a concentration of 350 parts per billion volume 

(ppbv) (Ref. 10, p. 10; 11B, p.102). An exterior soil gas investigation was conducted by Ohio EPA between 

the suspected source area and the well field in March 2007 (Ref. 10, p.10; 12B, pp. 1, 2). The figure in Ref. 

10A on page 3 illustrates the sample locations with respect to the plume axis. PCE was detected at low levels 

in 4 soil gas samples (Ref. 10 A, pp. 2, 3, 5, 9). The investigations completed to date have not been able to 

determine the full extent of the ground water plume or sources contributing to the ground water contamination.

2.2.2 Hazardous Substances Associated with the Source

The following ground water data are presented to illustrate the hazardous substances associated with Source 1. 

As part of the SESI conducted by OEPA, ground water samples were collected from 15 monitoring wells on 

August 4 and 5, 2009 (Ref. 10, pp. 6, 13). Three of four Milford public wells (PW-1, PW-2 and PW-4) were 

sampled on August 5, 2009, and again on September 14, 2009 (Ref. 10, p. 6). All four public wells (PW-1 

through PW-4) were re-sampled on February 2, 2010 (Ref. 10, p. 6). The ground water samples were analyzed 

for VOCs by Mitkem Laboratories Inc. and DataChem Laboratories using the CLP SOW SOM01.2 (6/2007) 

(Ref. 10, pp. 5, 26, 27).

The hazardous substances associated with Source 1 are PCE; TCE; cis-1,2-DCE; and 1,1,1-TCA. Figure 6 

shows the location of Source 1. 

Background Levels

- Background Level at Source 1 – Other -- Contaminant Plume

: 

The water elevations recorded in the Baker Drive wells were compared to the water elevations measured in 

wells installed during the geographic initiative and the combined PA/SI (Ref. 8, p. 12). The water table is 

approximately 20 feet shallower at Baker Drive than near the well field, which indicates that ground water 

flows west from Baker Drive to the well field (Ref. 8, p. 12). Based on this ground water flow direction, 

monitoring well locations MW-3 and MW-16 are considered upgradient or sidegradient (or background) 

locations (Refs.10, p. 13, 24; 12A, pp. 1-4). Municipal well PW-4 is also considered to be a background well 

because concentrations of chlorinated solvents detected in this well are either non-detect or at estimated 
17

concentrations below Contract-Required Quantitation Limits (CRQLs) (Ref. 10, pp. 14, 15). The background 

well sample locations are shown in Figure 5 of this HRS documentation record.

Table 1 below summarizes background monitoring well and public well location information and the 

concentrations of contaminants of concern for the site detected in ground water samples collected from each 

location. The contaminants of concern for the Milford Contaminated Aquifer site (PCE; TCE; cis-1,2-DCE; 

and 1,1,1-TCA) were not detected in ground water samples collected from the background locations, 

demonstrating that the background locations have not been impacted by the site-related hazardous substances. 

(See Table 1 of this HRS documentation record).

Furthermore, ground water samples were collected from direct-push locations GP7, GP11, GP12, GP13, GP21, 

and GP32. Based on the ground water flow direction described above, these locations are also considered to 

be upgradient or sidegradient (or background) locations. The ground water samples from direct push locations 

were collected from a depth of 39 to 64 feet below ground surface (bgs) (Refs. 8, pp. 18, 36, 37, 44). The 

contaminants of concern for the Milford Contaminated Aquifer site (PCE; TCE; cis-1,2-DCE and 1,1,1-TCA) 

were not detected in ground water samples collected from the direct-push background locations (Ref. 8, pp. 36, 

37, 103, 110, 112, 113, 119, 121, 122, 128, 136, 137, 143, 169, 170, 176). Absence of contaminants of 

concern in the direct-push ground water samples suggests that the background locations to the depth of 

approximately 64 feet bgs lie outside the area of contamination. Based on the description provided in the 

PSARA Technology Inc. June 2002 Report the direct-push samples appear to have been collected from the 

unconfined aquifer (Ref. 8, pp. 28, 44, 58, 59, 66, 67). Figure 4 of the ESI report shows these direct-push 

background locations (Ref. 8, p. 18).

TABLE 1

BACKGROUND LOCATION INFORMATION

Location 

No. Aquifer

Well or 

Sampling

Depth

(feet bgs)

Well

Screen 

Interval

(feet)

Sample 

No.

Sampling 

Date

Hazardous 

Substance

Concentration 

Detected (μg/L)

CRQL

(μg/L) References

PW-4 UC 25-51 36-51 E2467 2/2/2010 PCE 0.5 U 0.5 Refs. 10, pp. 15, 

16, 338-343, 

346,347, 350, 

372, 373, 381-

386;13, p.8; 

14A, pp.1, 2

TCE 0.5 U 0.5

Cis-1,2-DCE 0.5 U 0.5

1,1,1-TCA 0.5 U 0.5

MW-3 UC 28.45-38.45 30-40 E2341 8/6/09 PCE 5.0 U 5.0 Refs. 10, pp. 13, 

14, 22, 23, 24, 

27-33, 43, 44, 

47, 48, 51, 125, 

126, 127, 128- 

142, 408; 14 A, 

pp. 1, 2;.12, p. 

60

TCE 5.0 U 5.0

Cis-1,2-DCE 5.0 U 5.0

1,1,1-TCA 5.0 U 5.0
18

Location 

No. Aquifer

Well or 

Sampling

Depth

(feet bgs)

Well

Screen 

Interval

(feet)

Sample 

No.

Sampling 

Date

Hazardous 

Substance

Concentration 

Detected (μg/L)

CRQL

(μg/L) References

MW-16 UC 30.4-40.4 30-40 E2332 8/5/09 PCE 5.0 U 5.0 Refs. 10, pp. 13, 

14, 22, 23, 24, 

27-33, 37, 38, 

47, 48, 50, 88, 

89, 90, 128-142, 

418; 14 A, pp. 1, 

2 

TCE 5.0 U 5.0

Cis-1,2-DCE 5.0 U 5.0

1,1,1-TCA 5.0 U 5.0

Notes:

μg/L – Microgram per liter 

bgs – Below ground surface 

DCE - Dichloroethene

PCE – Tetrachloroethene

CRQL – Contract-Required Quantitation Limit (Ref. 14A, pp. 1, 2) 

TCA - Trichloroethane

TCE - Trichloroethene

UC – Unconfined aquifer

U – Analyte was analyzed for, but was not detected above the reported sample quantitation limit (Ref. 10, pp. 33, 343).

Contaminated Samples

- Contaminated Samples at Source 1 – Contaminated Plume 

: 

The results for contaminated ground water samples collected from monitoring wells and public wells at the 

Milford Contaminated Aquifer site are summarized in Table 2 below. The sample locations are shown in 

Figure 5 of this HRS documentation record package.

TABLE 2

CONTAMINATED SAMPLE INFORMATION

Location 

No. Aquifer

Well or 

Sampling

Depth

(feet bgs)

Well

Screen 

Interval

(feet)

Sample 

No.

Sampling 

Date

Hazardous 

Substance

Concentration

Detected (μg/L)

CRQL

(μg/L) References

MW-10D UC 50.41 40-50 E2325 8/4/09 PCE 9.6 5 Ref. 10, pp. 13, 

14, 24- 33, 36, 

47, 48, 49, 68, 

128-142, 412; 

14A, p. 2

MW-15 UC 55 45-55 E2331 8/5/09 16 5 Ref. 10, pp. 13, 

14, 24- 33, 38, 

47, 48, 50, 86, 

128-142, 417; 

14A, p. 2

MW-18 UC 54.4 44-54 E2334 8/5/09 40 5 Ref. 10, pp. 13, 

14 , 24- 33, 38, 

47, 48, 50, 95, 

128-142, 420; 

14A, p. 2
19

Location 

No. Aquifer

Well or 

Sampling

Depth

(feet bgs)

Well

Screen 

Interval

(feet)

Sample 

No.

Sampling 

Date

Hazardous 

Substance

Concentration

Detected (μg/L)

CRQL

(μg/L) References

MW-19 UC 49.91 40-50 E2335 8/5/09 31 5 Ref. 10, pp. 13, 

14 , 24- 33, 40, 

47, 48, 50, 98, 

128-142, 421; 

14A, p. 2

MW-14 UC 57.9 47-57 E2330 8/4/09 1100 5 Ref. 10, pp. 13, 

14 , 24- 33, 38, 

47, 48, 50, 83, 

128-142, 416; 

14A, p. 2

MW-17 UC 54.45 45-55 E2333 8/5/09 530 5 Ref. 10, pp. 13, 

14, 24- 33, 38, 

47, 48, 50, 92, 

128-142, 419; 

14A, p. 2

MW-20 UC 54.35 45-55 E2336DL 8/5/09 1100 D 50* Ref. 10, pp. 13, 

14, 24- 33, 40, 

47, 48, 50, 108, 

128-142, 422; 

14A, p. 2

PW-1 UC 59.83 39.83-

59.83

E2464 12/2/10 1.2 0.5 Ref. 10, pp. 15, 

16, 338-343, 

345, 348-350, 

360, 381-386; 

13, pp. 2, 9; 

14A, p. 2

PW-3 UC 63 43-63 E2466 1 2/2/10 9.9 0.5 Ref. 10, pp. 15, 

16, 338-343, 

345, 348-350, 

370, 381-386; 

13, pp. 7, 9; 

14A, p. 2; 14B

MW-14 UC 57.9 47-57 E2330 8/4/09 TCE 78 5 Ref. 10, pp. 13, 

14 , 24- 33, 37, 

47, 48, 50, 83, 

128-142, 416; 

14A, p. 1

MW-17 UC 54.45 45-55 E2333 8/5/09 39 5 Ref. 10, pp. 13, 

14 , 24- 33, 37, 

47, 48, 50, 92, 

128-142, 419; 

14A, p. 1

MW-20 UC 54.35 45-55 E2336 8/5/09 57 5 Ref. 10, pp. 13, 

14, 24- 33, 39, 

47, 48, 50, 105, 

128-142, 422; 

14A, p. 1

MW-20 UC 54.35 45-55 E2336 8/5/09 Cis-1,2-DCE 9.5 5 Ref. 10, pp. 13, 

14, 24- 33, 39, 

47, 48, 50, 104, 

128-142, 422; 

14A, p. 1
20

Location 

No. Aquifer

Well or 

Sampling

Depth

(feet bgs)

Well

Screen 

Interval

(feet)

Sample 

No.

Sampling 

Date

Hazardous 

Substance

Concentration

Detected (μg/L)

CRQL

(μg/L) References

PW-1 UC 59.83 39.83-

59.83

E2464 12/2/10 1,1,1-TCA 9.6 0.5 Ref. 10, pp. 15, 

16, 24-33, 338-

343, 344, 348-

350, 359, 381-

386; 13, pp. 2, 

9; 14A, p. 1

PW-2 UC 61 41-61 E2320 1 8/5/09 3.6 0.5 Ref. 10, pp. 15, 

16, 24-33, 153-

157, 159, 163-

165, 181, 193-

195; 13, pp. 3, 5, 

9; 14A, p. 1

MW-5S UC 34.65 25-35 E2340 8/4/09 17 5 Ref. 10, pp. 13, 

14, 24- 33, 41, 

47, 48, 51, 122, 

128-142, 409; 

14A, p. 1

MW-5D UC 64.41 55-65 E2339 8/4/09 45 5 Ref. 10, pp. 13, 

14, 24- 33, 41, 

47, 48, 51, 119, 

128-142, 410; 

14A, p. 1

MW-10S UC 29.28 19-29 E2326 8/4/09 13 5 Ref. 10, pp. 13, 

14, 24- 33, 35, 

47, 48, 49, 70, 

128-142, 411; 

14A, p. 1

MW-11 UC 69.2 60-70 E2327 8/6/09 10 5 Ref. 10, pp. 13, 

14, 24- 33, 35, 

47, 48, 49, 73, 

128-142, 413; 

14A, p. 1

Notes:

1 

The monitoring well samples were collected within the same time frame (between August 4 and 6, 2009) (Ref. 

10, pp. 49-51). The samples were collected using bladder pump using low-flow sampling technique (Ref. 10, 

pp. 13, 408-422). The ground water samples were collected after the field parameters (pH, conductivity, 

dissolved oxygen (DO), temperature, oxidation reduction potential and turbidity) had stabilized (Ref. 10, pp. 

-- The screen interval was estimated based on the well depth and screen length provided in Reference 13, page 9.

μg/L – Microgram per liter 

bgs – Below ground surface

DCE – Dichloroethene

D - Analysis was performed at a secondary dilution factor

NA – Not available

PCE – Tetrachloroethene

CRQL – Contract-Required Quantitation Limit (Ref. 14A, pp. 1, 2)

TCA –Trichloroethane

TCE – Trichloroethene

UC – Unconfined aquifer

* - Dilution of 10 was performed on this sample (Ref. 10, pp. 39, 108).
21

13, 408-422). The samples were analyzed by the U.S. EPA (CLP) for VOCs (Ref. 10, pp. 49-51; Tables 1 and 

2). 

The background and downgradient ground water samples were collected using bladder pump and the low-flow 

sampling procedures (Ref. 10, pp. 408-422); were collected within the same time frame (between 4th August 

2009 and 6th August 2009) and therefore, the same weather conditions (Ref. 10, pp. 408-422); were collected 

within the same aquifer (glacial deposits, Little Miami River Aquifer) (Ref. 8, pp. 44, 47, 80, 81; 10, pp. 408-

422; 11A, pp. 37-40); and were analyzed using the same methods (Ref. 10, pp. 49-51; Tables 1 and 2). 

The ground water samples from drinking water wells (public supply wells) were collected three times between 

August 2009 and February 2010 (Ref. 10, pp. 404-407, 447-450). The samples collected in August 2009 were 

collected on the same day by the same sampler (Ref. 10, pp. 404-407); and samples collected in February 2010 

were collected on the same day by the same sampler (Ref. 10, pp. 447-450). The samples were analyzed by 

the U.S. EPA CLP for VOCs (Ref. 10, pp. 49-51, 217, 350; Tables 1 and 2).

• TCE 

List of Hazardous Substances Associated with Source: 

The following hazardous substances are associated with the source:

• Cis-1,2-DCE 

• 1,1,1-TCA 

• PCE

2.2.3 Hazardous Substances Available to a Pathway

The soil boring investigations at the site have shown that the site has no liner, maintained engineered cover, 

functioning and maintained run-on control system, runoff management system, or functioning leachate 

collection and removal system (Refs. 6, pp. 42-57; 7, pp. 20-37; 8, pp. 49-77; 10, pp. 427-446). Furthermore, 

a ground water release of hazardous constituents from unknown sources is documented based on analytical 

results for ground water samples collected from the site. Therefore, the Containment Factor Value (CFV) for 

the ground water migration pathway was assigned a maximum value of 10 (Ref. 1, Section 3.1.2.1, Table 3-2, 

p. 51596). The maximum CFV reflects the minimum level of containment. A source is assigned the 

maximum CFV if there is evidence that hazardous substances have migrated from the source area or that there 

is no liner, maintained engineered cover, functioning leachate collection and removal system, or functioning 

and maintained run-on control system and runoff management system (Ref. 1, Section 3.1.2.1, Table 3-2, p. 

51596). 
22

Because the CFV for Source 1 is greater than zero, the following substances are identified as having been 

released to the ground water migration pathway: TCE; PCE; cis-1,2-DCE; and 1,1,1-TCA. Table 3 below 

summarizes the CFVs for each pathway.

TABLE 3

CONTAINMENT FACTOR VALUE SUMMARY

Release Description CFV Reference

Gas Release to Air Not Scored NA

Particulate Release to Air Not Scored NA

Release to Ground Water: Because there is an observed release 

of hazardous substances to ground water, a CFV of 10 was 

assigned (see Sections 2.2.2 and 3.1.1 of this HRS 

documentation record package).

10 Ref. 1, Section 3.1.2.1, 

Table 3-2, p. 51596

Release through Overland Migration and/or Flood Not Scored NA

Notes:

CFV - Containment Factor Value

HRS - Hazard Ranking System

NA - Not applicable

2.4.2 HAZARDOUS WASTE QUANTITY

2.4.2.1 Source Hazardous Waste Quantity

2.4.2.1.1 Hazardous Constituent Quantity (Tier A)

The available information is not sufficient to adequately evaluate Tier A as required in Section 2.4.2.1.1 of the 

HRS. As a result, the evaluation of Hazardous Waste Quantity proceeds to the evaluation of Tier B, hazardous 

wastestream quantity (Ref. 1, Section 2.4.2.1.1, pp. 51590-51591). 

2.4.2.1.2 Hazardous Wastestream Quantity (Tier B)

The available information is not sufficient to adequately evaluate Tier B as required in Section 2.4.2.1.2 of the 

HRS. As a result, the evaluation of Hazardous Waste Quantity proceeds to the evaluation of Tier C, volume 

(Ref. 1, Section 2.4.2.1.2, p. 51591). 

2.4.2.1.3 Volume (Tier C)

Because the lateral and vertical extent of the ground water plume have not been adequately characterized, the 

volume for the ground water plume is designated as unknown but greater than zero (Tier C) (Ref. 1, Section 

2.4.2.1.3, Table 2-6, p. 51591). 

2.4.2.1.4 Area (Tier D)

The area (Tier D) is not evaluated for source type “other” (Ref. 1, Table 2-5, p. 51591). 
23

2.4.2.2 Calculation of Hazardous Waste Quantity Factor Value

As described in the HRS, the highest value assigned to a source from among the four tiers of hazardous 

constituent quantity (Tier A), hazardous wastestream quantity (Tier B), volume (Tier C), or area (Tier D) shall 

be selected as the source hazardous waste quantity value (Ref. 1, Section 2.4.2.1.5, p. 51591). Table 4 below 

summarizes the hazardous waste quantity values.

TABLE 4

HAZARDOUS WASTE QUANTITY VALUES

Tier Measure Source Value

Tier A, Hazardous Constituent Quantity Not Evaluated

Tier B, Hazardous Wastestream Quantity Not Evaluated

Tier C, Volume >0

Tier D, Area Not Applicable

Table 5 below summarizes the source description.

TABLE 5

SOURCE DESCRIPTION SUMMARY

Source 

No.

Source

Hazardous

Waste

Quantity

Value

Source

Hazardous

Constituent

Quantity

Complete?

CFV by Pathway

Ground 

Water Surface Water Air

(Ref. 1, 

Table 3-2)

Overland/

Flood

(Ref. 1, Table 4-2)

Ground Water to 

Surface Water

(Ref. 1, Table 3-2)

Gas

(Ref. 1, 

Table 6-3)

Particulate

(Table 6-9)

1 Unknown, 

but >0 No 10 Not scored Not scored Not scored Not scored

Note:

CFV - Containment Factor Value

Description of Other Possible Sources: 

Historical Releases of Chlorinated Solvents from Other Possible Operations

Baker Feed Property and Nearby Area: Based on previous ground water investigations, the area at or near 

Baker Feeds, 527 Baker Drive is believed to be one possible historic contributor to the ground water 

contamination (Ref. 10, p. 7). Baker Feeds consists of several buildings including the feed store (the oldest 

structure), the Baker Party Store and two storage buildings (Figure 5, Source Area Investigation Map) (Ref. 10, 

p. 7). The party store is divided into three sections (Ref. 10, p. 7). Currently the southern two sections closest 

to the feed store are used as the Baker Party Store (Ref. 10, p. 7). The northern-most section is currently 

unoccupied but was used for dry cleaning in the past according to the current owner (Ref. 10, p. 7). Historical 

research conducted by Ohio EPA using Polk Directories indicates that Bernges 1-Hour Martinizing operated at 
24

527 Baker Drive at least between 1957 and 1967 (Ref. 10, pp. 7, 8). Additional evidence includes a large 

circular fan housing in the north wall of the building (Ref. 10, p. 8). This is believed to be the vent for the dry 

cleaning operation (Ref. 10, p. 8). The former dry cleaning operation in the party store building is the only 

link to PCE use that Ohio EPA was able to find. In September, 2002, Ohio EPA conducted an Expanded Site 

Inspection (ESI). ESI field work was conducted in four phases on March 18 through 22, May 13 through 17, 

June 6, and July 9, 2002 (Refs. 8, p. 5; 9A, p. 7). OEPA collected ground water samples from both Direct 

Push and rotosonic boreholes (Ref. 10, p. 9). Monitoring wells were installed and sampled to look for 

contaminant source areas and to delineate the pathways by which VOCs were entering the well field (Ref. 10, 

p. 9). OEPA advanced 36 soil borings, collected 27 ground water samples from the direct-push boreholes, and 

installed and sampled 3 monitoring wells (Refs. 8, p. 5; 9A, pp. 7, 20, 21). The ground water samples were 

submitted to DataChem Laboratories in Cincinnati, Ohio, for rush analysis using U.S. Environmental 

Protection Agency (EPA) Method 8260 (Refs. 8, p.5; 9A, p. 7). PCE was detected in direct-push ground water 

samples at concentrations of up to 730J μg/L; 1,1,1-TCA was detected at concentrations of up to 19 μg/L; 

TCE was detected at concentrations of up to 40 μg/L; and cis-1,2-DCE was detected at concentrations of up to 

40 μg/L (Ref. 9A, pp. 11, 12). Based on screening results from borehole sampling, monitoring wells MW-14, 

MW-15 and MW-16 were installed and sampled during the ESI (Ref. 10, p. 9). MW-14 and MW-15 were 

installed along Baker Drive; MW-16 was installed at the COMCO facility (Ref. 8, p. 8). The analytical results 

indicated that the aquifer was contaminated with VOCs which could be emanating from more than one source 

(Ref. 10, p. 9). The pattern of detections indicated that a release of PCE occurred in the vicinity of the Milford 

Shopping Center located approximately 3300 feet east of the well field (Refs. 8, p. 13; 10, p. 9). ESI sampling 

also documented low concentrations of residual VOCs in ground water at the COMCO facility (Ref. 10, p. 9). 

Ohio EPA conducted a Direct-Push investigation in 2003 to further define a source of PCE found in MW-14 

along Baker Drive (Ref. 10, p. 9). The Ohio EPA contractor, Tetra Tech EM Inc. completed 18 borings in the 

Milford Shopping Center parking lot, east of Baker Drive and in the Big Lots parking lot, on the north side of 

Main Street (Refs. 7, pp. 9, 10, 11, 16; 10, p. 9). Figure 3 of this HRS documentation record illustrates the 

results of the direct-push ground water samples collected from these borings. In April and May 2006, Tetra 

Tech EM Inc. completed ten soil borings and installed four monitoring wells in the Baker Feeds area to further 

define the suspected source area (Ref. 10, p. 10; 11A, pp. 5, 6, 7). Nine ground water samples and one soil 

sample were collected from borings installed in the study area (Ref. 11A, p. 12). The samples were analyzed 

for VOCs by Kemron Environmental Services using Method 8260A (Ref. 11A, p. 17). The direct-push ground 

water samples revealed levels of PCE in the vicinity of the Baker Feed Store (Ref. 11A, p. 18, Fig. 5-1).

Ohio EPA conducted a State Site Assessment Investigation in September 2006 collecting sub-slab soil gas 

sampling in buildings surrounding a suspected source property (Refs. 10, p. 10; 11B, pp. 2-21, 94-109). PCE 

was detected in the sub-slab sample at the Baker Party Store at a concentration of 350 parts per billion volume 

(ppbv) (Ref. 10, pp. 10; 11B, p. 102 ). An exterior soil gas investigation was conducted by Ohio EPA between 
25

a suspected source area and the well field in March 2007 (Ref. 10, p. 10; 12B, pp. 1, 2). The soil gas samples 

were analyzed for VOCs by DataChem using Method TO-14 (Ref. 12B, pp. 2, 11-22). PCE was detected at 

low levels in 4 of 13 soil gas samples (Ref. 10A, pp. 2, 3, 5, 9). Additionally, ground water samples were 

collected from the monitoring wells (Ref. 12B, pp. 24-76, 165). Based on ground water data, OEPA 

concluded that a source of contamination still appeared to be at or near the Baker Feeds property (Ref. 10, p. 

18). 

OEPA prepared a SESI work plan that was approved by U.S. EPA on July 9, 2009 (Ref. 10, p. 6). SESI field 

work included sampling of 15 monitoring wells; public supply wells; and 5 soil samples (including 1 

duplicate) for a potential source area identification (Ref. 10, pp. 6, 12, 13, 23-25). The samples were analyzed 

for target compound list VOCs by an EPA contract laboratory (Ref. 10, p. 6). The soil and ground water 

samples were submitted to Mitkem Laboratories Inc. in Warwick, Rhode Island, and DataChem Laboratories 

in Salt Lake City, Utah for analysis using CLP SOW SOM01.2 (Ref. 10, pp. 27, 28, 202). The SESI ground 

water samples confirmed that the aquifer is contaminated with VOCs (Ref.10, p. 6). Of the 5 soil samples 

collected, one sample contained concentrations of site-related contaminants: estimated concentrations of PCE 

and DCE at levels below the CRQL. Thus, the soil sampling was not able to identify a source (Ref. 10, pp. 13, 

16, 18). 

Mosler Inc: On June 9, 1986, the former Mosler Inc. (Mosler) facility located approximately 1 mile east of 

the well field filed a Notification of Hazardous Waste Activity form (Ref. 8, p. 7). The form indicates that the 

facility handled F001 listed wastes (Ref. 8, p. 7). F001 listed wastes are defined as spent halogenated solvents 

used for degreasing, including PCE, TCE, and 1,1,1-TCA, all of which have been detected in ground water 

samples collected from the City of Milford well field (Ref. 8, p. 7). Mosler operated a solvent vapor degreaser 

that used 1,1,1-TCA for parts cleaning (Ref. 8, p. 7). The Mosler facility ceased operations in 1991 (Ref. 8, p. 

7). Site investigations conducted in the early 1990s revealed that 1,1,1-TCA and other solvents had been 

released to soil and ground water at the Mosler facility (Ref. 8, p. 7). Contaminated soils were removed from 

the Mosler facility in 1992 and 1993, and a soil vapor extraction system was installed in 1995 (Ref. 8, p. 7). 

Soil and ground water sampling performed in 1996 indicated that most of the contamination had been removed 

(Ref. 8, p. 7). The Mosler facility is currently occupied by COMCO Machinery (COMCO), a division of 

MARKANDY (Ref. 8, p. 7). The figure on Reference 8, page 19 illustrates that MW-16 is located on the 

former Mosler (now COMCO) property, and during the 2002 ESI was found to contain levels of PCE and 

1,1,1-TCA. At present, it is not known if the ground water contamination at the former Mosler property is or 

was commingled with the Milford Contaminated Aquifer plume.

 
26

3.0 GROUND WATER MIGRATION PATHWAY

Analysis of the several field investigations near the Milford Treatment Plant and installed wells indicate the 

bedrock surface is generally encountered at a depth from ground surface ranging from 38 feet in the southern 

part of the Indian Hill wellfield to greater than 60 feet around the production wells in Milford's wellfield (Ref. 

10, pp. 10, 11). The Little Miami River Aquifer is unconfined and thus it receives direct recharge from 

precipitation (Ref. 10, p. 11). 

Geology and Hydrogeology:

The Milford well field is located in the north-south trending valley of the Little Miami River (Ref. 8, p. 12). 

The East Fork of the Little Miami River flows into the Little Miami River just south of Milford (Ref. 8, p. 12). 

Below the junction, the Little Miami River valley is broader (approximately 11⁄2 miles wide) than at Milford, 

where the valley is approximately 1⁄2 mile wide (Ref. 8, p. 12). The broad valley continues upstream along the 

East Fork. The narrowness of the valley at Milford suggests a recent origin (Ref. 8, p. 12). The valley 

between Milford and Foster was formed when a glacier blocked the westward flow of Todd’s Fork, forming a 

lake that overflowed the divide at Foster and carved the present valley (Ref. 8, p. 12). A pumping test of PW-3 

conducted in 1987 revealed that the hydraulic conductivity of the sand and gravel aquifer was 7,900 gallons 

per day (gpd) per square foot (Ref. 8, p. 12).

During the 2002 ESI, the depth to the water table was shallower at the COMCO property well (MW16) than in 

the Baker Drive wells (MW14 and MW15) (Ref. 8, p. 12), suggesting that ground water flows north from the 

COMCO property toward Baker Drive (Ref. 8, p. 12). The water elevations recorded in the Baker Drive wells 

were compared to the water elevations measured in wells installed during the geographic initiative and the 

combined PA/SI (Ref. 8, p. 12). The water table is approximately 20 feet shallower at Baker Drive than near 

the well field, which indicates that ground water flows west from Baker Drive toward the well field and the 

Little Miami River (Refs. 8, p. 12; 12A, pp. 1-3).

Clermont County is within the Till Plains section of the Central Lowland physiographic province. Uppermost 

subsurface materials in the area typically consist of Pleistocene glacial deposits which are predominately clayrich glacial till, with sand or gravel in places (Ref. 10, p. 10). The glacial cover ranges in thickness from 20 to 

more than 50 feet in areas near the Little Miami River and overlies interbedded shale and thin, hard, blue-gray 

limestone of Ordovician age (Ref. 10, p. 10). 

The Milford Well Field is located in the flood plain of the Little Miami River, which consists of permeable 

sand and gravel deposits “comprised of both pre- and post-glacial alluvium" (Ref. 10, p. 10). The Little 

Miami River Aquifer near Milford is typified by layers of coarse, unconsolidated, permeable sand and gravel 

with minimal occurrences of clay sediments (Ref. 10, p. 10). 
27

With respect to water production, the area along the Little Miami River is particularly favorable because of 

induced stream infiltration (Ref. 10, p. 11). Much of a well's yield is likely derived from the induced 

infiltration from the Little Miami River (Ref. 10, p. 11). The annual average of precipitation in the Milford 

area is 37.7 inches of which approximately one-third infiltrates and recharges the ground water (Ref. 10, p. 

11). Additional recharge to the aquifer occurs through the fractures in the bedrock and the valley walls (Ref. 

10, p. 11). However, this amount of recharge is negligible compared to the areal recharge component (Ref. 10, 

p. 11).

The City of Milford lies on the northeastern edge of a very large buried valley system (Ref. 12, p. 22). The 

aquifer in the vicinity of the Milford water treatment plant is a buried channel containing sand and gravel 

deposits (Ref. 12, p. 46). The composition of the surficial deposits is highly variable (Ref. 12, p. 22). 

Geologic samples collected in Milford indicate that the soil is a mixture of ancient buried channel deposits and 

recent alluvial deposits (Ref. 12, p. 22). In general, approximately 50 feet of unconsolidated materials were 

present in borings drilled during the geological investigations and the upper 10 feet was composed of silt, 

loam, clay, and fill, while the remainder was composed of sand and gravel (Ref. 11, pp. 14, 38-57). Although 

the sand and gravel contained silt and clay, no clay or other low-permeability material layers were encountered 

in the geological investigation borings that could impede the movement of water (Ref. 11, p. 14). The absence 

of thick laterally extensive clay layers indicates that the aquifer in the vicinity of the Milford water treatment 

plant is unconfined (Ref. 12, pp. 24, 25, 46). 

Based on the investigations conducted at the site and a geologic cross section developed for the site, the 

contaminated ground water plume is located in the Pleistocene glacial deposits overlying the interbedded shale 

and thin, hard, blue-gray limestone of Ordovician age (Refs. 8, pp. 44, 47; 10, p. 10; 12, p. 60). The public 

supply wells are located in the Pleistocene glacial deposits (also known as the Little Miami River Aquifer) 

(Ref. 14, p. 1). 

Aquifer Interconnection/Discontinuity

The hydrogeologic setting across the study area is characterized as a buried valley, with one smaller area of 

glacial till directly overlying bedrock (Ref. 10 B, pp. 34, 44; 12, pp. 22, 46). The geology of this buried valley 

consists of thick deposits of sand and gravel deposited by glacial meltwaters in former river valleys (Ref. 10 B, 

p. 40). The cross section developed for the site indicates that abundant sand and gravel deposits are present 

throughout the study area and shows that no discontinuities between the eastern and western portions of the 

study area are likely (Ref. 8, pp. 44, 46, 47). The glacial till identified in this cross section appears to be

localized and is not likely to hinder ground water flow from east to west (Ref. 8, pp. 44, 46; 10 B, 44). Based 

on the similar hydrogeologic conditions across the study area, it is expected that the sand and gravel deposits 

are continuous throughout the study area. 

: 
28

The sand and gravel aquifer at the Milford Contaminated Aquifer site is an unconfined water table aquifer. 

The absence of thick laterally extensive clay layers in the sediment indicates that the aquifer in the vicinity of 

the Milford water treatment plant is unconfined (Ref. 5, p. 42; Ref. 10, pp. 24, 25). Because the aquifer is 

unconfined and contains no continuous layer of low hydraulic conductivity material, there is no need to 

demonstrate aquifer interconnection. Table 6 below summarizes the aquifer characteristics. 

TABLE 6

AQUIFER CHARACTERISTICS SUMMARY

Source No. Aquifer Type

Is Aquifer Continuous 

Within-4-Mile Target 

Distance Limit? Is Aquifer Karst?

1 Unconsolidated Yes No

3.1 LIKELIHOOD OF RELEASE

3.1.1 Observed Release

Aquifer Being Evaluated: Little Miami River Aquifer (Unconfined Aquifer).

Direct Observation: An observed release by direct observation to the ground water migration pathway from the 

unconsolidated aquifer has not been established at the Milford Contaminated Aquifer site. 

Chemical Analysis: 

Establishing an observed release through chemical analysis requires analytical evidence of a hazardous 

substance in a medium at a concentration significantly exceeding the background concentration. If the 

background concentration of a chemical is not detected (or is less than the detection limit), an observed release 

is established when a sample measurement equals or exceeds its own sample quantitation limit (SQL) and the 

background sample concentration. If the SQL cannot be established, the EPA contract-required quantitation 

limit (CRQL) should be used instead of the SQL (Ref. 1, Section 2.3, p. 51589). 

The water elevations recorded in the Baker Drive wells were compared to the water elevations measured in 

wells installed during the geographic initiative and the combined PA/SI (Ref. 8, p. 12). The water table is 

approximately 20 feet shallower at Baker Drive than near the well field, which indicates that ground water 

flows west from Baker Drive to the well field (Ref. 8, p. 12). Based on this ground water flow direction, 

monitoring well locations MW-3 and MW-16 are considered upgradient or sidegradient (or background) 

locations (Refs.10, pp. 13, 24; 12A, pp. 1-4). Municipal well PW-4 is also considered to be a background well 

because concentrations of chlorinated solvents detected in this well are either non-detect or at estimated 

Background Level:
29

concentrations below Contract Required Quantitation Limits (CRQLs) (Ref. 10, pp. 14, 15). The background 

well sample locations are shown in Figure 5 of this HRS documentation record.

Table 7 below summarizes background monitoring well and public well location information and the 

concentrations of contaminants of concern for the site detected in ground water samples collected from each 

location. The contaminants of concern for the Milford Contaminated Aquifer site (PCE; TCE; cis-1,2-DCE; 

and 1,1,1-TCA) were not detected in ground water samples collected from the background locations, 

demonstrating that the background locations have not been impacted by the site-related hazardous substances.

(See Table 7 of this HRS documentation record). 

Furthermore, ground water samples were collected from direct-push locations GP7, GP11, GP12, GP13, GP21, 

and GP32. Based on the ground water flow direction described above, these locations are also considered to 

be upgradient (or background) locations. The ground water samples from direct push locations were collected 

from a depth of 39 to 64 feet below ground surface (bgs) (Refs. 8, pp. 18, 36, 37, 44). The contaminants of 

concern for the Milford Contaminated Aquifer site (PCE; TCE; cis-1,2-DCE and 1,1,1-TCA) were not detected 

in ground water samples collected from the direct-push background locations (Ref. 8, pp. 36, 37, 103, 110, 

112, 113, 119, 121, 122, 128, 136, 137, 143, 169, 170, 176). Absence of contaminants of concern in the directpush ground water samples suggests that the background locations to the depth of approximately 64 feet bgs 

lie outside the area of contamination. Based on the description provided in the PSARA Technology Inc. June 

2002 Report, the direct-push samples appear to have been collected from the unconfined aquifer (Ref. 8, pp. 

28, 44, 58, 59, 66, 67). Figure 4 of the ESI report shows these direct-push background locations (Ref. 8, p. 

18).

TABLE 7

BACKGROUND WELL INFORMATION

Location 

No. Aquifer

Well or 

Sampling

Depth

(feet bgs)

Well

Screen 

Interval

(feet)

Sample 

No.

Sampling 

Date

Hazardous 

Substance

Concentration 

Detected (μg/L)

CRQL

(μg/L) References

PW-4 UC 25-51 36-51 E2467 2/2/2010 PCE 0.5 U 0.5 Refs. 10, pp. 15, 

16, 338-343, 

346, 347, 350, 

372, 373, 381-

386; 13, p.8; 

14A, pp.1, 2 

TCE 0.5 U 0.5

Cis-1,2-DCE 0.5 U 0.5

1,1,1-TCA 0.5 U 0.5

MW-3 UC 28.45-38.45 30-40 E2341 8/6/09 PCE 5.0 U 5.0 Refs. 10, pp. 13, 

14, 22, 23, 24, 

27-33, 43, 44, 

TCE 5.0 U 5.0

Cis-1,2-DCE 5.0 U 5.0
30

Location 

No. Aquifer

Well or 

Sampling

Depth

(feet bgs)

Well

Screen 

Interval

(feet)

Sample 

No.

Sampling 

Date

Hazardous 

Substance

Concentration 

Detected (μg/L)

CRQL

(μg/L) References

1,1,1-TCA 5.0 U 5.0 47, 48, 51, 125, 

126, 127, 128- 

142, 408; 14 A, 

pp. 1, 2;. 12, p. 

60

MW-16 UC 30.4-40.4 30-40 E2332 8/5/09 PCE 5.0 U 5.0 Refs. 10, pp. 13, 

14, 22, 23, 24, 

27-33, 37, 38, 

47, 48, 50, 88, 

89, 90, 128-142, 

418; 14 A, pp. 1, 

2

TCE 5.0 U 5.0

Cis-1,2-DCE 5.0 U 5.0

1,1,1-TCA 5.0 U 5.0

Notes:

μg/L – Microgram per liter 

bgs – Below ground surface 

DCE - Dichloroethene

PCE – Tetrachloroethene

CRQL – Contract-Required Quantitation Limit (Ref. 14A, pp. 1, 2)

TCA - Trichloroethane

TCE – Trichloroethene

UC – Unconfined aquifer

U – Analyte was analyzed for, but was not detected above the reported sample quantitation limit (Ref. 10, pp. 33, 343).

- Contaminated Samples 

The results for contaminated ground water samples collected from monitoring wells and public wells at the 

Milford Contaminated Aquifer site are summarized in Table 8 below. The sample locations are shown in 

Figure 5 of this HRS documentation record.

TABLE 8

CONTAMINATED WELL INFORMATION

Location 

No. Aquifer

Well or 

Sampling

Depth

(feet bgs)

Well

Screen 

Interval

(feet)

Sample 

No.

Sampling 

Date

Hazardous 

Substance

Concentration 

Detected (μg/L)

CRQL

(μg/L) References

MW-10D UC 50.41 40-50 E2325 8/4/09 PCE 9.6 5 Ref. 10, pp. 13, 

14, 24- 33, 36, 

47, 48, 49, 68, 

128-142, 412; 

14A, p. 2

MW-15 UC 55 45-55 E2331 8/5/09 16 5 Ref. 10, pp. 13, 

14, 24- 33, 38, 

47, 48, 50, 86, 

128-142, 417; 

14A, p. 2
31

Location 

No. Aquifer

Well or 

Sampling

Depth

(feet bgs)

Well

Screen 

Interval

(feet)

Sample 

No.

Sampling 

Date

Hazardous 

Substance

Concentration 

Detected (μg/L)

CRQL

(μg/L) References

MW-18 UC 54.4 44-54 E2334 8/5/09 40 5 Ref. 10, pp. 13, 

14 , 24- 33, 38, 

47, 48, 50, 95, 

128-142, 420; 

14A, p. 2

MW-19 UC 49.91 40-50 E2335 8/5/09 31 5 Ref. 10, pp. 13, 

14 , 24- 33, 40, 

47, 48, 50, 98, 

128-142, 421; 

14A, p. 2

MW-14 UC 57.9 47-57 E2330 8/4/09 1100 5 Ref. 10, pp. 13, 

14 , 24- 33, 38, 

47, 48, 50, 83, 

128-142, 416; 

14A, p. 2

MW-17 UC 54.45 45-55 E2333 8/5/09 530 5 Ref. 10, pp. 13, 

14, 24- 33, 38, 

47, 48, 50, 92, 

128-142, 419; 

14A, p. 2

MW-20 UC 54.35 45-55 E2336DL 8/5/09 1100 D 50* Ref. 10, pp. 13, 

14, 24- 33, 40, 

47, 48, 50, 108, 

128-142, 422; 

14A, p. 2

PW-1 UC 59.83 39.83-

59.83

E2464 12/2/10 1.2 0.5 Ref. 10, pp. 15, 

16, 338-343, 

345, 348-350, 

360, 381-386; 

13, pp. 2, 9; 

14A, p. 2

PW-3 UC 63 43-63 E2466 1 2/2/10 9.9 0.5 Ref. 10, pp. 15, 

16, 338-343, 

345, 348-350, 

370, 381-386; 

13, pp. 7, 9; 

14A, p. 2; 14B

MW-14 UC 57.9 47-57 E2330 8/4/09 TCE 78 5 Ref. 10, pp. 13, 

14 , 24- 33, 37, 

47, 48, 50, 83, 

128-142, 416; 

14A, p. 1

MW-17 UC 54.45 45-55 E2333 8/5/09 39 5 Ref. 10, pp. 13, 

14 , 24- 33, 37,

47, 48, 50, 92, 

128-142, 419; 

14A, p. 1

MW-20 UC 54.35 45-55 E2336 8/5/09 57 5 Ref. 10, pp. 13, 

14, 24- 33, 39, 

47, 48, 50, 105, 

128-142, 422; 

14A, p. 1

MW-20 UC 54.35 45-55 E2336 8/5/09 Cis-1,2-DCE 9.5 5 Ref. 10, pp. 13, 
32

Location 

No. Aquifer

Well or 

Sampling

Depth

(feet bgs)

Well

Screen 

Interval

(feet)

Sample 

No.

Sampling 

Date

Hazardous 

Substance

Concentration 

Detected (μg/L)

CRQL

(μg/L) References

14, 24- 33, 39, 

47, 48, 50, 104, 

128-142, 422; 

14A, p. 1

PW-1 UC 59.83 39.83-

59.83

E2464 12/2/10 1,1,1-TCA 9.6 0.5 Ref. 10, pp. 15, 

16, 24-33, 338-

343, 344, 348-

350, 359, 381-

386; 13, pp. 2, 

9; 14A, p. 1

PW-2 UC 61 41-61 E2320 1 8/5/09 3.6 0.5 Ref. 10, pp. 15, 

16, 24-33, 153-

157, 159, 163-

165, 181, 193-

195; 13, p. 3, 5, 

9; 14A, p. 1

MW-5S UC 34.65 25-35 E2340 8/4/09 17 5 Ref. 10, pp. 13, 

14, 24- 33, 41, 

47, 48, 51, 122, 

128-142, 409; 

14A, p. 1

MW-5D UC 64.41 55-65 E2339 8/4/09 45 5 Ref. 10, pp. 13, 

14, 24- 33, 41, 

47, 48, 51, 119, 

128-142, 410; 

14A, p. 1

MW-10S UC 29.28 19-29 E2326 8/4/09 13 5 Ref. 10, pp. 13, 

14, 24- 33, 35, 

47, 48, 49, 70, 

128-142, 411; 

14A, p. 1

MW-11 UC 69.2 60-70 E2327 8/6/09 10 5 Ref. 10, pp. 13, 

14, 24- 33, 35, 

47, 48, 49, 73, 

128-142, 413; 

14A, p. 1

Notes:

1 -- The screen interval was estimated based on the well depth and screen length provided in Reference 13, page 9.

μg/L – Microgram per liter 

bgs – Below ground surface

DCE – Dichloroethene

D - Analysis was performed at a secondary dilution factor

PCE – Tetrachloroethene

CRQL – Contract-Required Quantitation Limit (Ref. 14A, pp. 1, 2)

TCA –Trichloroethane

TCE – Trichloroethene

UC – Unconfined aquifer

* - Dilution of 10 was performed on this sample (Ref. 10, pp. 39, 108).
33

The monitoring well samples were collected within the same time frame (between August 4 and 6, 2009) (Ref. 

10, pp. 49-51). The samples were collected using bladder pump using low-flow sampling technique (Ref. 10, 

pp. 13, 408-422). The ground water samples were collected after the field parameters (pH, conductivity, 

dissolved oxygen (DO), temperature, oxidation-reduction potential and turbidity) had stabilized (Ref. 10, pp. 

13, 408-422). The samples were analyzed by the U.S. EPA (CLP) for VOCs (Ref. 10, pp. 49-51; Tables 1 and 

2). 

The background and downgradient ground water samples were collected using bladder pump and the low-flow 

sampling procedures (Ref. 10, pp. 408-422); were collected within the same time frame (between 4th August 

2009 and 6th August 2009) and therefore, the same weather conditions (Ref. 10, pp. 408-422); were collected 

within the same aquifer (glacial deposits, Little Miami River Aquifer) (Ref. 8, pp, 44, 47, 80, 81; 10, pp. 408-

422; 11A, pp. 37-40); and were analyzed using the same methods (Ref. 10 pp. 49-51; Tables 1 and 2). 

The ground water samples from drinking water wells (public supply wells) were collected three times between 

August 2009 and February 2010 (Ref. 10, pp. 404-407, 447-450). The samples collected in August 2009 were 

collected on the same day by the same sampler (Ref. 10, pp. 404-407); and samples collected in February 2010 

were collected on the same day by the same sampler (Ref. 10, pp. 447-450). The samples were analyzed by 

the U.S. EPA CLP for VOCs (Ref. 10, pp. 49-51, 217, 350; Tables 1 and 2). 

Milford Contaminated Aquifer Plume Releases (Contaminated Plume): 

The Milford Contaminated Aquifer plume has received releases from unidentified source(s). Releases 

associated with the plume area were detected through chemical analysis of ground water samples collected 

from numerous direct-push soil borings, monitoring wells, and municipal wells. Analytical results for ground 

water samples collected from the plume area document observed releases to ground water, primarily of PCE; 

TCE; cis-1,2-DCE; and 1,1,1-TCA (see Table 8 above, Contaminated Sample Information). As discussed in 

Section 3.1.1 above, if the background concentration of a chemical is not detected (or is less than the detection 

limit), an observed release is established when a sample measurement equals or exceeds its own SQL and the 

background sample concentration. If the SQL cannot be established, the EPA CRQL should be used instead of 

the SQL (Ref. 1, Section 2.3, p. 51589). VOCs were not detected in background wells, so all detected VOC 

concentrations exceeding the detection limit qualify as observed release. 

Attribution

The Milford Contaminated Aquifer site plume has received releases of PCE and 1,1,1-TCA from unidentified 

source(s). The plume also contains TCE and cis-1,2-DCE, which are biodegradation products of PCE and 

TCE. PCE; cis-1,2-DCE; 1,1,1-TCA; and TCE do not exist naturally and are manmade chemicals (Ref. 13 C, 

pp. 2, 5). Significant ground water sampling has been performed to identify sources of the PCE and 1,1,1-

: 
34

TCA contamination, but no sources have yet been identified. Vadose Research, Inc. (VRI), conducted soil gas 

survey and monitoring well sampling to identify the potential source(s) of ground water contamination in the 

vicinity of the City of Milford Well Field (Ref. 13 A, p. 5). The potential sources identified for investigation 

in the vicinity of the City of Milford Well field include a U-Haul dealer on a site formerly occupied by a Ford 

automobile dealership; Victor Tire dealer, on a site formerly occupied by a retail gasoline station and fuels 

distributorship; Clermont Savings, on a site formerly occupied by a historical gasoline station; Milford City 

Garage, near city well # 3; Milford City shop/storage buildings, near city well # 3; a site formerly occupied by 

a dry cleaner, now a vacant lot; and dry wells, integral with the city storm water system, located immediately 

east of the new garage and behind the U-Haul dealer at the north end of their back lot (Ref. 13 A, p.10). As 

part of this investigation soil gas samples were collected from 115 locations and ground water samples were 

collected from 7 locations (Ref. 13 A, pp. 5, 18). Based on the VRI investigation 3 primary source areas were 

identified (Refs. 13A, pp. 42, 43; 13B, p. 19). The 3 primary source areas that were identified during VRI 

investigations include the U-Haul dealer on a site formerly occupied by a Ford automobile dealership; the 

Victor Tire dealer, and a site formerly occupied by a dry cleaner, now a vacant lot (Ref. 13A, pp. 42, 43, 48). 

Ohio EPA collected approximately 12 soil samples to confirm contamination in areas indicated to be 

contaminated by the soil-gas survey (Ref. 13B, pp.12, 17, 18, 21). The only VOCs detected by the laboratory 

were methylene chloride and acetone (Ref. 13B, p. 17). These are common laboratory contaminants and are 

not believed to occur at the site (Ref. 13B, p. 17). Neither chemical has been listed as a contaminant in the 

well field (Ref. 13B, p. 17). No semivolatile organic compounds were detected (Ref. 13B, p. 17). Even 

though the soil gas sampling identified 3 potential sources, the follow-up soil confirmatory sampling by OEPA 

was not able to confirm these sources. Based on this information it appears that the above listed locations have 

not been identified as potential sources for the plume. 

Based on the investigations performed on several potential source areas, the ground water contamination 

source cannot be identified or reasonably attributed with confidence. Because the source is a contaminated 

ground water plume with no positively identified source of contamination, no separate attribution is required

(Ref. 1, Section 3.1.1, p. 51595). 

• TCE 

Hazardous Substances Released: 

The following hazardous substances have been released from the source:

• Cis-1,2-DCE 

• 1,1,1-TCA 

• PCE

Ground Water Observed Release Factor Value: 550 
35

3.1.2 Potential to Release 

As specified in the HRS, because an observed release has been established for the aquifer, the potential to 

release was not scored (Ref. 1, Section 3.1.2, p. 51595). 

3.2 WASTE CHARACTERISTICS 

The ground water plume at Milford primarily is composed of PCE; TCE; cis-1,2-DCE; and 1,1,1-TCA. The 

contamination is described as a ground water plume with no identified source. PCE; TCE; cis-1,2-DCE; and 

1,1,1-TCA were detected in several wells at concentrations exceeding the background levels. Ground water 

samples collected from municipal wells PW-1 and PW-3 have been shown to be impacted by 1,1,1-TCA and 

PCE (Ref. 10, pp. 15, 16). TCE and cis-1,2-DCE were detected in estimated quantity in the ground water 

sample obtained from the municipal well PW-1 (Ref. 10, pp. 15, 16). 1,1,1-TCA was detected in the ground 

water sample obtained from the municipal well PW-2 (Ref. 10, pp. 15, 16). PCE was in estimated quantity in 

the ground water sample obtained from the municipal well PW-2 (Ref. 10, pp. 15, 16). PCE, TCE , 1,1,1 

TCA and cis-1,2-DCE were detected in the ground water sample obtained from the municipal well PW-3 (Ref. 

10, p. 16). 1,1,1 TCA was detected in estimated quantity in the ground water sample obtained from the 

municipal well PW-4 (Ref. 10, p. 15). The released substances are believed to be from an unknown source 

or sources east of the municipal wells. 

3.2.1 Toxicity/Mobility 

All hazardous substances listed in Table 9 below are documented in ground water samples collected from the 

Milford Contaminated Aquifer plume. These hazardous substances were detected at concentrations 

significantly exceeding background levels. 
36

TABLE 9

OBSERVED RELEASE AND TOXICITY/MOBILITY SUMMARY

Hazardous

Substance

Toxicity 

Factor 

Value

Mobility 

Factor 

Value

Does Hazardous 

Substance Meet 

Observed Release 

Criteria?

Toxicity/ 

Mobility Reference

PCE 100 1 Yes 100 Ref. 1, Sections 3.2.1.1, 

3.2.1.2, and 3.2.1.3, pp. 

51601, 51602; Ref. 2, p. A336

TCE 10,000 1 Yes 10,000 Ref. 1, Sections 3.2.1.1, 

3.2.1.2, and 3.2.1.3, pp. 

51601, 51602; Ref. 2, p. A-2

Cis-1,2-DCE 100 1 Yes 100 Ref. 1, Sections 3.2.1.1, 

3.2.1.2, and 3.2.1.3, pp. 

51601, 51602; Ref. 2, p. A134

1,1,1-TCA 1 1 Yes 1 Ref. 1, Sections 3.2.1.1, 

3.2.1.2, and 3.2.1.3, pp. 

51601, 51602; Ref. 2, p. A362

Notes:

DCE - Dichloroethene

PCE – Tetrachloroethene

TCA - Trichloroethane

TCE – Trichloroethene

Because an observed release to the ground water migration pathway has been established, a mobility factor of 

1 was applied to the hazardous substances released (Ref. 1, Section 3.2.1.2, p. 51601). As shown in Table 9 

above, the toxicity/mobility factor value for TCE is 10,000. The Toxicity/Mobility Factor Value of 10,000 

was assigned based on Table 3-9 of the HRS (Ref. 1, Section 3.2.1.3, p. 51602). 

Toxicity/Mobility Factor Value: 10,000

3.2.2 Hazardous Waste Quantity

Table 10 below summarizes the hazardous waste quantity information for the Milford Contaminated Aquifer. 

TABLE 10

HAZARDOUS WASTE QUANTITY SUMMARY

Source No. Source Name Source Type Source Hazardous Waste 

Quantity

1 Other Ground Water Plume Unknown but > 0

The Milford Contaminated Aquifer site has been scored as a contaminated ground water plume with no 

identified source. According to Section 2.4.2.2 in the HRS (Ref. 1, p. 51592), if any target for the migration 
37

pathway is subject to Level I or Level II concentrations, and the hazardous constituent quantity is not 

adequately determined, the Hazardous Waste Quantity Factor Value for that pathway should either be assigned 

the value from Table 2-6 (Ref. 1, p. 51591) or a value of 100, whichever is greater. Because Level I 

concentrations were detected in samples from a drinking water well (see Section 3.3.2.2 of this HRS 

documentation record package), a Hazardous Waste Quantity Factor Value of 100 was assigned to the ground 

water pathway. 

Hazardous Waste Quantity Factor Value: 100 

(Ref. 1, Section 2.4.2.2, p. 51592) 

3.2.3 Calculation of Waste Characteristics Factor Category Value

As specified in the HRS (Ref. 1, Section 3.2.3, p. 51602), the Hazardous Waste Quantity Factor Value of 100 

was multiplied by the highest Toxicity/Mobility Factor Value of 10,000, resulting in a product of 1,000,000 

(1.0E+06). Based on this product, a Waste Characteristics Factor Category Value of 32 was assigned from 

Table 2-7 of the HRS (Ref. 1, Section 2.4.3.1, p. 51592). The highest Toxicity/Mobility Factor Value of the 

substances listed in Section 3.2.1 of this HRS documentation record package was for TCE. 

Toxicity/Mobility Factor Value: 10,000

Hazardous Waste Quantity Factor Value: 100 

Toxicity/Mobility Factor Value (10,000) X Hazardous Waste Quantity Factor Value (100): 

1,000,000 = 1X106

 

Waste Characteristics Factor Category Value: 32

(Ref. 1, Table 2-7, p. 51592) 

3.3 TARGETS

A total of 18 municipal wells are located within the 4- mile radius Target Distance Limit (TDL) from the site 

(Ref. 14, p. 1; Ref. 15, p. 1; Ref. 16, p. 1). The 4-mile target distance limit (TDL) is shown in Reference 20. 

The primary municipal wells of concern are operated by the City of Milford municipal water system (Ref. 6, p. 

10). Three municipal wells (PW-1, PW-2 and PW-3) operated by the City of Milford are within the ground 

water contamination plume and are impacted by the chemicals of concern (Tables 11 and 12). Approximately 

24 private wells within the TDL could potentially be exposed to contaminated drinking water. An estimated 

63 people are served by private wells within the TDL (Ref. 17, pp. 2-5). The targets evaluated for the ground 

water migration pathway are summarized below. 

Level I Concentrations
38

Level I concentrations have been documented in one City of Milford public supply well (PW-3) that draws 

from the Little Miami River Aquifer as shown in Table 11 below. 

TABLE 11 

LEVEL I CONCENTRATIONS 

Sample ID

Hazardous 

Substance

Hazardous

Substance 

Concentration 

(μg/L)

Benchmark 

Concentration 

(μg/L) Benchmark

References 

for 

Benchmark

E2466 

(PW-3) 

PCE 9.9 1.6 Cancer Risk 

Screening 

Concentration 

2, p. A-336

Notes: 

See Table 8 for the concentrations detected in the drinking water well samples. 

μg/L Micrograms per liter

ID Identification

Level II Concentrations

Level II concentrations have been documented in two of the City of Milford public water supply wells (PW-1 

and PW-2) that draw from the Little Miami River Aquifer and are summarized in Table 12 below. 

TABLE 12 

LEVEL II CONCENTRATIONS 

Hazardous 

Substance

Hazardous

Substance

Concentration 

(μg/L)

Benchmark 

Concentration 

(μg/L) Benchmark

References 

for 

Benchmark

E2

Sample ID

464 

(PW-1) 

PCE 1.2 1.6 Cancer Risk 

Screening 

Concentration 

2, p. A-336

E2464 

(PW-1) 

1,1,1-TCA 9.6 200 MCL 2, p. A-362

E2320 

(PW-2) 

1,1,1-TCA 3.6 200 MCL 2, p. A-362

Notes: 

See Table 8 for the concentrations detected in the drinking water well samples. 

μg/L Micrograms per liter

ID Identification

MCL Maximum contaminant level
39

3.3.1 Nearest Well

Because actual contamination at Level I concentrations has been documented, a nearest well factor value of 50 

is assigned (Ref. 1, Section 3.3.1, Table 3-11, p. 51603). 

Well ID: PW-3 

Level of Contamination (I, II, or potential): I 

Nearest Well Factor Value: 50 

(Ref. 1, Table 3-11, p. 51603) 

3.3.2 Population 

3.3.2.1 Level of Contamination 

The City of Milford municipal system has approximately 2,077 service connections (Ref. 14, p. 2). According 

to the U.S. Census Bureau, there are approximately 2.67 persons per household in Clermont County (Ref. 17, 

p. 1). Therefore, the total estimated population served by the City of Milford water system is 5,546 (2,077 

total service connections x 2.67 persons per household for Clermont county). The City of Milford water 

system has four municipal wells (PW-1 through PW-4) (Ref. 14, p. 1). The water pumped from these wells is 

blended (Ref. 14, pp. 1, 2). Water from PW-1 and PW-3 is treated by an air stripper prior to distribution due to 

chlorinated solvents contamination (Ref. 14, p. 1, 2). 

The annual pumping rate for each municipal well was provided by the City of Milford Water Department for 

2006, 2007, and 2008 (Ref. 14, pp. 2, 3). For population allocation, the data from 2007 were used because in 

2006 municipal well PW-4 was being designed and because in 2008, municipal wells PW-1 and PW-3 were 

not used because the air stripper was being repaired (Ref. 14, pp. 2, 3). According to 2007 data, the annual 

pumping rates were as follows: for PW-1, 0 gallons (0 percent); for PW-2, 219.07 million gallons (79.4 

percent of total pumping volume); for PW-3, 44.02 million gallons (16 percent of the total pumping volume); 

and for PW-4, 12.74 million gallons (4.6 percent of total pumping volume) (Ref. 14, p. 2). Based on the 

annual pumping rates for 2007, municipal well PW-2 supplied more than 40 percent of the system’s total 

water. Therefore, the population was apportioned to each municipal well in accordance with the annual 

pumping rates (Ref. 1, Section 3.3.2, p. 51603; Ref. 14, pp. 1-2). 
40

3.3.2.2 Level I Concentrations

Level I Well

Level I Population Targets

For municipal well PW-3, the population allocated was 887 individuals (16 percent of 5,546 individuals). The 

Level I well is documented in Tables 8 and 11. Table 13 summarizes the Level I population affected by PW-3, 

which is completed in the Little Miami River aquifer. 

TABLE 13

LEVEL I POPULATION

Aquifer Population Reference

PW-3 Unconfined or 

Little Miami 

River Aquifer

887 14

Sum of Population Served by Level I Wells: 887

Sum of Population Served by Level I Wells x 10: 8,870 (Ref. 1, Section 3.3.2.2, p. 51603). 

Level I Concentrations Factor Value: 8,870 

3.3.2.3 Level II Concentrations

Level II Well

Level II Population Targets

For municipal well PW-1, the population allocated was 0 individuals (PW-1 provided 0 gallons in 2007). For 

municipal well PW-2, the population allocated was 4,404 individuals (79.4 percent of 5,546 individuals). The 

Level II wells are documented in Tables 8 and 12. Table 14 summarizes the Level II population affected by 

PW-1 and PW-2, which are completed in the Little Miami River aquifer. 

TABLE 14

LEVEL II POPULATION

Aquifer Population Reference

PW-1 Unconfined or 

Little Miami 

River Aquifer

0 14

PW-2 Unconfined or 

Little Miami 

River Aquifer

4,404 14
41

Sum of Population Served by Level II Wells: 4,404 (Ref. 1, Section 3.3.2.3, p. 51603). 

Level II Concentrations Factor Value: 4,404 

3.3.2.4 Potential Contamination

Because Level I and II concentrations provide the maximum score for the ground water migration pathway, the 

potential contamination factor was not scored for this HRS documentation record package. Although potential 

contamination was not scored, there is a concern about populations that could be exposed to contaminated 

drinking water. 

Potential Contamination Factor Value: Not Scored

3.3.3 RESOURCES

Ground water within the 4-mile radius TDL is not used as a resource (Ref. 14, p. 3; Ref. 15, p. 2). Therefore, 

the Resources Factor was assigned a value of 0 (Ref. 1, Section 3.3.3, p. 51604). 

Resources Factor Value: 0

3.3.4 WELLHEAD PROTECTION AREA

There is no Wellhead Protection Area in the area of contaminated ground water (Ref. 1, Section 3.3.4, page 

51604; Ref. 14, p. 1; and Ref. 19, p. 10). The Milford Water Department is currently working under the 

direction of OEPA to formulate a Wellhead Protection Program (Ref. 14, p. 1; Ref. 19, p. 10). Therefore, the 

Wellhead Protection Area Factor was assigned a value of 0 (Ref. 1, Section 3.3.4, p. 51604). 

Wellhead Protection Area Factor Value: 0

3.3.5 CALCULATION OF TARGETS FACTOR CATEGORY VALUE 

The total target factor category value is the sum of the nearest well, population, resources, and wellhead 

protection area values (Ref. 1, Section 3.3.5, p. 51604). The total target factor category value for the site is 50

(nearest well) + 13,274 (population) + 0 (resources) + 0 (wellhead protection area) = 13,324.