HRS DOCUMENTATION RECORD COVER SHEET

Name of Site: PCE Southeast Contamination 

EPA ID No.: NEN000706200 

Contact Persons 

EPA Contact : Michelle Quick, EPA Region 7 NPL Coordinator 

 Brian Mitchell, EPA Nebraska State Coordinator

 U.S. Environmental Protection Agency, Region 7 

Site Investigation: U.S. Environmental Protection Agency 

 Nebraska Department of Natural Resources

Documentation Record: Kumud Pyakuryal, Tetra Tech, Inc.

Pathways, Components, or Threats Not Scored 

No releases or impacts to surface water or air have been documented. The surface water and air migration 

pathways and the soil exposure pathway were not scored because these pathways would not affect the 

NPL decision. 
1 

HRS DOCUMENTATION RECORD

Name of Site: PCE Southeast Contamination 

EPA Region: 7 

Date Prepared: December 2013 

Street Address of Site*: Intersection of 5th Street and Lincoln Avenue. 

City, County, State, Zip: York, York County, Nebraska, 68467 

General Location in the State: The site is located in York, near the center of York County in southeast 

Nebraska (York South (USGS 1969b) (Figure 1; Ref. 3, pp. 1).

Topographic Map: The location of the site is shown on the York South Quadrangle, 

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

(Ref. 3, p. 1).

Latitude*: 40o 51’ 34.54” North (Ref. 3, p. 1) 

Longitude*: 97o 34’ 50.21” West (Ref. 3, p. 1) 

The latitude and longitude listed above specify the approximate location of the center of the ground water 

plume, located on the north side of the West Nobes Road (Road 12) between Blackburn Avenue and 

South Delaware Street. It is an area-wide ground water plume with no identified source. 

Scores

Ground Water Migration Pathway 86.67

Surface Water Migration Pathway 0

Soil Exposure Pathway 0

Air Migration Pathway 0

HRS SITE SCORE 43.33

Note:

*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, disposed or placed, or has 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. 
2 

WORKSHEET FOR COMPUTING HRS SITE SCORE

S S2

1. Ground Water Migration Pathway Score (Sgw) 

(from Table 3-1, line 13) 86.67 7,511.68 

2a. Surface Water Overland/Flood Migration Component 

(from Table 4-1, line 30) 0.00 

2b. Ground Water to Surface Water Migration Component

(from Table 4-25, line 28) 0.00 

2c. Surface Water Migration Pathway Score (Ssw) 

Enter the larger of lines 2a and 2b as the pathway score. 0.00 0.00 

3. Soil Exposure Pathway Score (Ss) 

(from Table 5-1, line 22) 0.00 0.00 

4. Air Migration Pathway Score (Sa) 

(from Table 6-1, line 12) 0.00 0.00 

5. Total of Sgw

2 + Ssw2 + Ss2 + Sa2 7,511.68 

6. HRS Site Score Divide the value on line 5 

by 4 and take the square root 43.33 
3 

TABLE 3-1.−GROUND WATER MIGRATION PATHWAY SCORESHEET 

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 Not Scored

2b. Net Precipitation 10 Not Scored

2c. Depth to Aquifer 5 Not Scored

2d. Travel Time 35 Not Scored

2e. Potential to Release [lines 2a x (2b + 2c + 2d)] 500 Not Scored

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

Waste Characteristics:

4. Toxicity/Mobility a 1,000

5. Hazardous Waste Quantity a 100

6. Waste Characteristics 100 18

Targets:

7. Nearest Well 50 50

8. Population:

8a. Level I Concentrations b 225.00

8b. Level II Concentrations b 427.25

8c. Potential Contamination b Not Scored

8d. Population (lines 8a + 8b + 8c) b 652.25

9. Resources 5 Not Scored

10. Wellhead Protection Area 20 20

11. Targets (lines 7 + 8d + 9 + 10) b 722.25

GROUND WATER MIGRATION SOURCE FOR AN AQUIFER

12. Aquifer Source [(lines 3 x 6 x 11)/82,500]c 100 86.67

GROUND WATER MIGRATION PATHWAY SCORE

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

aquifers evaluated)c 100 86.67 

Notes:

a Maximum value applies to waste characteristics category

b Maximum value not applicable c Do not round to nearest integer 
4 

FIGURE 1.–GROUND WATER SAMPLING RESULTS MAP
5 

FIGURE 2.–4-MILE RADIUS MAP
6

REFERENCES

Reference 

Number Description of the Reference

1 U.S. Environmental Protection Agency (EPA). Hazard Ranking System, Final Rule. 55 FR 

51533. December 14, 1990. 1 page. On-line address: 

http://www.epa.gov/superfund/sites/npl/hrsres/. A complete copy of the HRS can be 

obtained at the Regional docket upon request.

2 EPA. Superfund Chemical Data Matrix. January 2004 (March 2012 update). Excerpt. 

5 pages. [Note: A complete copy of SCDM is available at 

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

3 U.S. Department of Interior Geological Survey (USGS). 1969. York South, Nebraska

Quadrangle, Missouri, 7.5-Minute Series (topographic) (1969). 1 page.

4 Tetra Tech, Inc. (Tetra Tech). 2012. Removal Site Evaluation/Site Inspection Report for 

Southeast York Groundwater Site, York, York County, Nebraska. February 16. 397 pages.

5 Tetra Tech, Inc. (Tetra Tech). 2012. Integrated Site Assessment Report for York 

Tetrachloroethene (PCE) Site, York, York County, Nebraska. February 14. 199 pages. 

6 Seagull Environmental Technologies, Inc. (SETI). 2011. Removal Site Evaluation/Site 

Inspection Report for Southeast York Groundwater Site, York, York County, Nebraska. 

February 16. 397 pages. 

7 U.S. Geologic Survey (USGS). 2007. Hydrogeologic Setting and Ground-Water Flow 

Simulations of the Eastern High Plains Regional Study Area, Nebraska. 32 pages.

8 NDHHS. 2013. Ground water sample result for PWS Well # 77-3, from September 6, 

2005; September 8, 2009; and September 29, 2011. On-line address: http://sdwisdhhs.ne.gov. Accessed on May 10, 2013. 9 pages.

9 U.S. Geologic Survey (USGS). 2008. Hydrogeology, Chemical Characteristics, and 

Transport Processes in the Zone of Contribution of a Public-Supply Well in York, 

Nebraska. Scientific Investigations Report 2008-5050. 165 pages. 

10 U.S. Census Bureau. 2010. Quickfacts Website. Accessed on March 27, 2013. On-line 

address: http://quickfacts.census.gov/qfd/. 2 pages.

11 Tetra Tech. 2013. Figure 1: Ground Water Sampling Results Map. Revised on August 5. 

1 page. 

12 Tetra Tech. 2013. Figure 2: 4-Mile Target Distance Limit (TDL). Revised on August 5. 

1 page. 

13 EPA. 1992. EPA Method 8260B, Revision 4.0. August. 43 pages.

14 Tetra Tech EM, Inc. (Tetra Tech). 2011. The Quality Assurance Project Plan for Removal 

Site Evaluation/Site Inspection at the Southeast York Groundwater site, York, York 

County, Nebraska. Contract No. EP-S7-06-01, Task Order No. 0222. May 20. 31 pages.

15 USGS. 2008. Simulations of Ground-Water Flow, Transport, Age, and Particle Tracking 

near York, Nebraska, for a study of Transport of Anthropogenic and Natural Contaminants 

(TANC) to Public Water Wells. 58 pages. 

16 EPA. 2013. Envirofacts Database. On-line Address: https://oaspub.epa.gov/enviro/. 

Accessed on August 2. 4 pages.

17 NDHSS. 2013. Drinking Water Branch – Drinking Water Watch Database. On-line 

Address: http://sdwis-dhhs.ne.gov:8000/DWW/. Accessed on August 5. 3 pages. 

18 Nebraska Department of Environmental Quality (NDEQ). 1999. Ground Water Section. 

Wellhead Protection Program. Wellhead Protection Area Map. 2 pages. 
7 

SITE SUMMARY

The PCE Southeast Contamination site is a ground water plume with no identified source resulting from 

multiple possible sources associated with past and present commercial and industrial operations near the 

intersection of North Lincoln Avenue and 5th Street in York, Nebraska (see Figures 1 and 2; 16, pp. 1-4). 

North Lincoln Avenue is the east-west division for city streets; 5th Street is near the central portion of the 

City of York, Nebraska. The approximate geographic coordinates for the PCE Southeast Contamination 

plume site are 40o 51’ 34.54” North and 97o 34’ 50.21” West, which is north of the York Municipal Well 

# 77-4, located on the north side of West Nobes Road (Road 12) between Blackburn Avenue and South 

Delaware Street (Figures 1 and 2). 

The site is composed of documented releases of hazardous substances, consisting of the volatile organic 

compounds (VOCs) tetrachloroethene (PCE) and trichloroethylene (TCE) into ground water, and detected 

in wells associated with the local public drinking water supply and private residences (Ref. 5, pp. 5-6; 23, 

p. 165; Section 2.2.1 of this Hazard Ranking System [HRS] documentation record). The driving factor 

for the HRS site score is drinking water targets that are subject to actual contamination. Recent EPA site 

investigations have documented VOCs in private drinking water wells at concentrations that exceeded the 

Cancer Risk (CR) screening concentrations and Maximum Contaminant Levels (MCL) (Ref. 2, p. 5). In 

addition, a public water well (well 77-4) sample collected by the U.S. Geological Survey (USGS) for its 

published 2008 Scientific Investigation Report documented PCE in the well at a concentration of 

4.56 μg/L (Ref. 9, pp. 21, 133). 
8 

2.2 SOURCE CHARACTERIZATION

EPA has conducted several investigations at this site since January of 2010. To date, EPA conducted an 

Abbreviated Preliminary Assessment dated January 19, 2010, a Site Inspection/Removal Site Evaluation

dated February 16, 2012, and an Integrated Site Assessment dated February 14, 2012 in order to 

determine the concentrations and extent of contamination, and identify possible source areas. 

2.2.1 SOURCE IDENTIFICATION

Name of source: - Southeast York Area Ground Water Plume (with no identified source)

Number of sources: - 1 

Source Type: - Contaminated ground water plume 

Description and Location of Sources (with reference to a map of the site): Figure 1

Source 1 encompasses an area of VOC-contaminated ground water – with PCE as the primary 

contaminant of concern but also TCE – including a public supply well, numerous private domestic 

drinking water supply wells, monitoring wells, and temporary wells in the York area (Refs. 4, pp.67-68). 

It is not possible to identify and associate the ground water plume with any specific source(s) of the 

contamination at this time. Therefore, the source has been identified as a ground water plume with no 

identifiable source.

The site consists of a PCE and TCE contaminated ground water plume, which are contaminants 

commonly associated with local historical industrial and commercial use. Analytical results have 

identified elevated levels of these contaminants in ground water; however, the extent of contamination 

has not been fully characterized (Ref. 4, pp. 21-27, 46-47, 69; 6, p. 18). The estimated center location of 

operations that resulted in the contaminated plume is annotated on the York, Nebraska U.S. Geological 

Survey 7.5-minute quadrangle maps (Ref. 3; 1). 

In 2010, an Abbreviated Preliminary Assessment (APA) was conducted by EPA. Private wells at four 

residences had PCE levels exceeding health-based benchmarks (Ref. 6, pp. 11-12). The more recent EPA 

CERCLA assessments associated with the site are the 2012 RSE/SI and 2012 Integrated Site Assessment 

(ISA) Report. Combined investigations from EPA indicated an area-wide ground water plume and some 

soil contamination, which are associated with local industrial and commercial operations (Ref. 4, p. 6, 8, 

14 5, pp. 6, 7). During the RSE/SI, PCE (ranging from 6.1 to 46 μg/L) was identified in six private wells, 

all exceeding the MCL. TCE was also detected the same six wells, with concentrations ranging from 0.89 

to 8.0 μg/L. One well, which also contained a PCE concentration of 21μg/L, was across the street from 

the location where TCE had exceeded the MCL in 2010 (Ref. 4, pp. 26-27). During the ISA, PCE and its 
9 

degradation products TCE, cis-1,2-DCE, and vinyl chloride were detected in temporary well (TW) ground

water samples collected near and downgradient of former dry cleaners or laundries operating near W. 

5th Street and N. Lincoln Avenue. PCE was detected at a maximum concentration of 280 μg/L in the 

ground water sample collected at 31 to 35 feet bgs at TW-20, located near the southeast (downgradient) 

corner of the former dry cleaners property at 423 N. Lincoln Avenue. The sample from 46 to 50 feet bgs 

at TW-20 contained 16 μg/L of PCE. PCE was also detected at 5.3 μg/L in the 31- to 35-foot bgs sample 

from TW-21, and at 73 μg/L in the 31- to 35-foot bgs sample from TW-27. These sample locations were 

about 150 feet west-northwest and 160 feet northwest of TW-20, respectively (Ref. 5, pp. 15-20, 40). 

EPA has performed studies in attempt to characterize the extent of the ground water contamination and 

has identified multiple possible industrial and commercial sources. Elevated levels of PCE and TCE have 

been detected in drinking water wells on multiple occasions between 2010 and 2012 (Ref. 4, p. 6, 8, 14; 5, 

pp. 6, 7). 

HAZARDOUS SUBSTANCES ASSOCIATED WITH THE SOURCE

The ground water plume source hazardous substances are those hazardous substances for which an 

observed release has been established. The contaminants of concern associated with the site used for 

scoring purposes are PCE and TCE. The results presented below from historical ground water sampling 

events document elevated levels of PCE and TCE at the site. 

Background Levels 

Public Supply Well 

Nebraska Department of Health and Human Services (NDHHS) data for public water supply well 77-3, 

located upgradient and about 1.5 miles northwest of public water supply well 77-4, indicate no VOCs in 

77-3 when sampled on September 6, 2005, September 8, 2008, and August 29, 2011 (8, pp. 1-9; 13, 

p. 33). Well 77-3 is not downgradient of possible sources; therefore it was selected as an appropriate 

background sample for comparing release samples collected from the public water supply (Ref. 5, 

pp. 25-26; 7, p. 25). 
10 

Table 1: Source Background Samples for Municipal Well Samples

Laboratory 

Sample 

Number Well ID

Dates 

Collected Analyte

Concentration 

(μg/L)

MDL

(μg/L)

Well 

Depth

(ft bgs)

Screened 

Intervals

(ft bgs) References

P28022-169 York PWS 

77-3a

09/06/2005 PCE

TCE

0.5 U

0.5 U

0.14

0.19

292 150-205

272-292

Ref. 4, p. 48; 

8, pp. 1-9; 

P34394-167 09/08/2008 PCE 13, p. 33

TCE

0.5 U

0.5 U

0.14

0.19

117905 08/29/2011 PCE

TCE

0.5 U

0.5 U

0.14

0.19

Notes:

* Because these samples were analyzed using EPA Method 524.2, the MDLs are provided. As per the method, MDLs 

are sufficient to detect analytes at the required levels according to the Safe Drinking Water Act regulations (Ref. 13, 

pp. 15-16). a See Figures 1 and 2 for location of sample included in Table 1.

ID Identification

μg/L micrograms per liter

U The analyte was not detected (the value next to “U” in the concentration column represents the method detection limit) 

ft bgs feet below ground surface

Private Wells

A dedicated background sample (Sample Number 5432-10) was collected by EPA in August 2011 and 

analyzed for VOCs (Ref. 4, pp. 26, 69). The sample listed in Table 2 was collected from private well and 

serves as a background for comparison to other private wells at the site. The background residential well 

was selected from an area that is generally upgradient and away from the contaminated wells (Ref. 4, p. 

69). Although well construction information is not available, most of the residential wells that met the 

observed release criteria are expected to draw drinking water from the same aquifer interval (Ref. 4, p. 

47). The background sample was collected using the same sampling plan as release samples associated 

with Analytical Services Request (ASR) 5432 (Ref. 4, pp. 1, 23-27, 14, pp. 1, 8-9, ). 
11 

Table 2: Source Background Samples for Private Well Samples

Laboratory 

Sample 

ID1, 2

Sampling 

Date or 

Analyzed 

Date

Hazardous 

Substance

Hazardous 

Substance 

Concentration

(μg/L)

Method 

Detection 

Limit

Well 

Depth

(ft bgs) References

5432-10 08/10/11

PCE 0.5 U 0.14 Unknown Ref. 4, pp. 123, 

TCE 0.5 U 0.19 Unknown 175, 299, 308-309

Notes:

1 This sample was analyzed for VOCs using EPA Region 7 Method 3230.09, which meets the requirements of EPA 

Method 524.2 (Ref 14, p. 8). The MDLs are provided. As per the method, MDLs are sufficient to detect analytes at 

the required levels according to the Safe Drinking Water Act regulations (Ref. 13, pp. 15-16). 2 See Figures 1 and 2 for the location of sample included in the table.

ID Identification

μg/L micrograms per liter

U The analyte was not detected (the value next to “U” in the concentration column represents the method detection limit) 

ft bgs feet below ground surface

Contaminated Samples 

The ground water pathway source hazardous substances are those hazardous substances for which an 

observed release was established within the evaluated aquifer. PCE was detected in public water supply 

well 77-4 on two known occasions since 2004 (Ref. 9, pp. 23, 133). 

As noted earlier, of a total of seven residential ground water well samples collected by EPA in support of 

the York RSE/SI, 5 (71 percent) contained PCE above the MCL of 5 μg/L. In addition, one private well 

sample (5349-1) collected in April 2011 in support of the EPA ISA and four private well samples 

(5105-3, 5105-17, 5105-18, and 5105-19) collected near the intersection of Road N and Road 12 

(E. Nobes Road) in November 2010 in support the EPA APA contained PCE concentrations above MCL. 

Because the most immediate health threat is deemed to be contaminated ground water used for drinking, 

EPA has planned supply of alternative water to residents with private wells contaminated with VOCs at 

concentrations above regulatory action levels (Ref. 5, pp. 196-197). 
12 

Table 3: Contaminated Wells

Laboratory Sample 

NumberC

Sampling 

Date or 

Analyzed 

Date

Hazardous 

Substance

Hazardous 

Substance 

Concentration 

(μg/L)

Method 

Detection 

Limita 

(μg/L)

Well 

Depth

(ft bgs) Reference

Study PWS Well, 

Depth 48.8 meters

06/17/2004 PCE 2.38 See Notesa 141 –

200b 

Ref. 9, pp. 23, 

133

Study PWS Well, 

Depth 51.8 meters

06/17/2004 PCE 4.56 See Notesa Ref. 9, pp. 23, 

133

5349-1 04/26/2011 PCE

TCE

46

4.9

0.14

0.19

Unknown Ref. 5, pp. 39, 

67-68, 116, 

120, 

5432-1 08/09/2011 PCE

TCE

6.1

2.0

0.14

0.19

Unknown Ref. 4, pp. 26, 

69, 124, 166, 

299, 304-305

5432-2 08/09/2011 PCE

TCE

21

8.0

0.14

0.19

Unknown Ref. 4, pp. 26, 

69, 124, 167, 

299, 304-305

5432-3 08/09/2011 PCE

TCE

8.2

0.89

0.14

0.19

Unknown Ref. 4, pp. 26, 

69, 124, 168, 

299, 304-305

5432-4 08/09/2011 PCE

TCE

11

1.5

0.14

0.19

Unknown Ref. 4, pp. 26, 

69, 124, 169, 

299, 304-305

5432-9 08/10/2011 PCE

TCE

12

3.8

0.14

0.19

Unknown Ref. 4, pp. 26, 

69, 124, 174, 

299, 308-309

5105-1 10/11/2010 PCE

TCE

0.59

0.50 U

0.14

0.19

Unknown Ref. 6, pp. 9, 

42, 75-76

5105-3 10/11/2010 PCE

TCE

12

5.9

0.14

0.19

Unknown Ref. 6, pp. 9, 

44, 75-76

5105-17 10/13/2010 PCE

TCE

30

0.88

0.14

0.19

Unknown Ref. 6, pp. 10, 

58

5105-18 10/13/2010 PCE

TCE

22

1.4

0.14

0.19

Unknown Ref. 6, pp. 10, 

59

5105-19 10/13/2010 PCE

TCE

22

2.1

0.14

0.19

Unknown Ref. 6, pp. 10, 

60

Notes:

a This sample was analyzed for VOCs using EPA Region 7 Method 3230.09, which meets the requirements of EPA 

Method 524.2 (Ref 14, p. 8). The MDLs are provided. As per the method, MDLs are sufficient to detect analytes at 

the required levels according to the Safe Drinking Water Act regulations (Ref. 13, pp. 15-16). b In June 2004, USGS collected ground water samples for various intervals within the screened interval (140-200 feet

bgs) at the PWS Study Well (identified by its location as well 77-4). Samples were collected using a 1-inch-diameter 

bladder pump lowered through a 1.5-inch polyvinyl chloride (PVC) pipe that had been installed to 140 feet bgs. USGS 

samples were identified by the pump depth and assumed to represent water from that depth and below. This data was 

published as a Scientific Investigations Report (2008-5050) by the USGS (Ref. 9, pp. 133) c See Figures 1 and 2 for location of samples included in Table 3.

PWS Public Water Supply

μg/L micrograms per liter

ft bgs feet below ground surface

USGS Unites States Department of the Interior, U.S. Geological Survey
13 

3.0.1 HAZARDOUS SUBSTANCES AVAILABLE TO A PATHWAY

Table 4: Containment Factor Value

Containment Description

Containment 

Factor Value Reference

Gas release to air Not Scored NA

Particulate release to air Not Scored NA

The containment factor value for the ground water migration pathway was 

evaluated for “All Sources” for evidence of hazardous substance migration 

from source area (i.e, source area includes source and any associated 

containment structures). The source is a ground water plume. The plume is 

defined as an area of contamination released to ground water and detected in 

ground water samples. Applicable containment factor value was determined 

based on existing analytical evidence of hazardous substances in ground 

water samples from private and public wells. Therefore, the highest ground 

water migration pathway containment factor value of 10 was assigned to 

Source Number 1 as specified in Table 3-2 of the HRS (Ref. 1, 

Section 3.1.2.1).

10 Ref. 7, pp. 46-48, 

30-32; 5, 

pp. 30-32; 6, 

pp. 8-9, 20

Release via overland migration and/or flood. Not Scored NA
14 

2.2.3 HAZARDOUS WASTE QUANTITY

2.4.2.1.1 Hazardous Constituent Quantity

The hazardous constituent quantity for Source No. 1 could not be adequately determined according to the 

HRS requirements; that is, the total mass of all CERCLA hazardous substances in the source is not known 

and cannot be estimated with reasonable confidence [Ref. 1, Section 2.4.2.1.1]. There are insufficient 

historical and current data (Manifests, PRP records, State records, permits, waste concentration data, etc.) 

available to adequately calculate the total mass of all CERCLA hazardous substances in the source and 

the associated releases from the source. Therefore, there is insufficient information to evaluate the 

associated releases from the source to calculate the hazardous constituent quantity for Source No. 1 with 

reasonable confidence. Hazardous Constituent Quantity Value: Not Scored

2.4.2.1.2 Hazardous Wastestream Quantity

The hazardous wastestream quantity for Source No. 1 could not be adequately determined according to 

the HRS requirements; that is, the total mass of all hazardous wastestreams and CERCLA pollutants and 

contaminants in the source is not known and cannot be estimated with reasonable confidence [Ref. 1, 

Section 2.4.2.1.2]. There are insufficient historical and current data (Manifests, PRP records, State 

records, permits, etc.) available to adequately calculate the total mass of all hazardous wastestreams and 

CERCLA pollutants and contaminants in the source and the associated releases from the source. 

Therefore, there is insufficient information to evaluate the associated releases from the source to calculate 

the hazardous wastestream quantity for Source No. 1 with reasonable confidence. Hazardous 

Wastestream Quantity Value: Not Scored

2.4.2.1.3 Volume

For the migration pathways, the source is assigned a value for volume using the appropriate Tier C 

equation from Table 2-5 (Ref. 1, Section 2.4.2.1.3). Because the extent of the ground water plume is 

unknown, the volume for the ground water plume will be designated as unknown, but contaminated 

ground water samples are present, so the quantity is greater than zero.

Volume: >0 

2.4.2.1.4 Area

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

Area: 0
15 

2.4.2.1.5 Source Hazardous Waste Quantity Value

Highest assigned value assigned from Table 2-5: >0
16 

Table 5: Summary of Source Descriptions

Source 

No.

Source 

Hazardous

Waste Quantity

Value

Source 

Hazardous 

Constituent 

Quantity 

Complete? 

(Y/N)

Containment Factor Value by Pathway

Ground 

Water 

(GW)

(Table 

3-2)

Surface Water (SW) Air

Overland/flood

(Table 4-2)

GW to 

SW

(Table

3-2)

Gas

(Table

6-3)

Particulate 

(Table

6-9)

1 >0 No 10 Not Scored Not 

Scored

Not 

Scored

Not Scored

Other Possible Sources 

There are many possible sources resulting from various operations such as dry cleaners (who often use 

tetrachloroethene [PCE]) and metal degreasing operations (who often use PCE or TCE)(Ref. 4, pp. 6-7; 5, 

pp. 5-6; 16, pp. 1-4). Earliest documented dry cleaning operation in the site area dates back to 1948. A 

list of known operations and facilities are discussed further in subsequent paragraphs. 

A dry cleaner (Deluxe Cleaners) is located at 609 N. Lincoln Avenue in downtown York. Historical city 

directories indicate this dry cleaners has been at this address since at least 1948 (oldest City directory 

available at the York Public Library). This address was shown as a storefront on 1933 and 1946 Sanborn 

maps (Ref. 4, pp. 386-387). Review of historical Sanborn Fire Insurance Maps and York city directories 

indicated that laundries, steam laundries, or dry cleaners were formerly located at 107 E. 6th Street (Foster 

Cleaners/Valet Cleaners, c. 1948-1961), 116 W. 7th Street (York Laundry and Dry Cleaners, 

c. 1960-1970), and 827 N. Lincoln Avenue (H&H Cleaners and Shirt Launderers, c. 1984-1991) (Ref. 4, 

pp. 39-42, 383-397). PCE was identified in a soil sample collected from 1-3 feet bgs at SB 4, located 

north of (behind) a former dry cleaner building at 107 E. 6th Street in downtown York (Ref. 4, pp. 13-14). 

Sanborn Fire Insurance Maps for 1933 and 1946 (updated 1933 map) indicate that a dry cleaner was also 

located at the western part of the lot at 423 N. Lincoln Avenue; a storefront building faced Lincoln 

Avenue at the eastern portion of the lot (Ref. 4, pp. 384, 386-387). These Sanborn maps indicate that 

buried solvent tanks were located along the alley west of the property. A 1915 Sanborn map indicates the 

western building was for “clothes cleaning” and the eastern storefront was for a tailor. Review of the 

York telephone directories at the York Public Library indicated that Blair Cleaners (formerly Olson 

Cleaners) was located at that address in 1948 (Ref. 4, pp. 12-13). The next available directory (1963) 

indicated a jewelry store was located at the address. Various jewelry stores were listed at the address 

through 1990 (Ref. 4, pp. 13). The storefront building is currently a law office, and the area where the 

western building had been located is gravel covered. A movie theatre is to the north; private parking lots 

are located to the south and across the alley to the west. A gas station had been previously located at the 
17 

northwest parking lot (southeast corner of W. 6th Street and N. Platte Avenue). The 1963 York city 

directory indicated an Econowash Laundromat was located at 508 N. Platte Avenue (north of the former 

gas station). This former laundromat, currently part of Chances R restaurant, may have had coin-operated 

dry cleaning machines (Ref. 4, pp. 12-13). 

A list of EPA-regulated facilities in the Envirofacts database is presented as Reference 16. 
18 

3.0 GROUND WATER MIGRATION PATHWAY

3.0.1 GENERAL CONSIDERATIONS

The site is situated in the High Plains aquifer area of Nebraska where Quaternary and undivided Tertiary 

units are present. Quaternary alluvial deposits of the High Plains aquifer provide ground water to wells in 

the area. This aquifer consists of fluvial sands, gravels, silts, and clays. The uppermost layer consists of 

unsaturated loess having a maximum thickness of about 88 feet in the York area. Below that is a 

maximum of about 140 feet of sand and gravel, with some lenses of silt and clay. The following 

paragraphs present a summary of the stratigraphy described by USGS and information for two deep 

USGS monitoring wells in the southern York area. USGS investigations in this area are discussed below.

Ground Water Migration Pathway Description

The upper portion of the aquifer has an average thickness of 68 feet and a maximum thickness of 140 feet. 

It underlies loess and is composed of sand and gravel, with some lenses of silt and clay. The water table 

occurs near the top of these sands and gravels. Typically, silts and clays and finer sands and gravels 

increase with depth in this layer (Ref. 7 p 9). This portion of the aquifer has a hydraulic conductivity of 

approximately 136 feet/day (Ref 7, pp 11, 13).

Below the sand and gravel is a silt deposit which acts as a semi-confining layer. Below the silt deposit is 

a clayey glacial till that is water bearing and producible. Below the clayey glacial till is another silt layer 

which acts as a semi-confining layer. Below the silt layer is about 80 feet of fine- to medium-grained 

sand, with minor amounts of gravel. Nearly all PWS wells and many irrigation wells in the area are fully 

screened across this sand and the hydraulic conductivity of this sand is approximately 65 feet/day 

Underlying this sand aquifer is a layer consisting of about 105 feet of silts and clays with some 

interbedded sands (Ref. 7, pp. 9-14). While this aquifer consists of many layers, evidence of 

contamination migration (as discussed below via leaky boreholes (Ref. 15 p. 35)), and ground water 

sample results demonstrate that any semi-confining or confining layers present are not functioning 

competent or impermeable barriers to ground water/contaminant flow in the site vicinity; thus the aquifer 

beneath the site is, for HRS scoring purposes, considered equivalent to a single interconnected aquifer 

system (Ref. 1, Section 3.0.1.2.2). 

USGS installed monitoring wells in the various aquifer layers as part of its investigations into ground 

water flow and contamination in the York area (Ref. 15, pp1-58). These monitoring wells were sampled 

for VOCs several times between 2003 and 2005, and a number of wells contained PCE and TCE (Ref. 15, 

pp. 133-165). Monitoring well FP1-63, located adjacent to PWS well 77-4, contained PCE (0.42 μg/L), 
19 

TCE (0.27 μg/L), and cis-1,2-DCE (0.16 μg/L) in samples from 242-247 feet bgs—the lower portion of 

the aquifer (Ref. 9, p.133). 

USGS also collected ground water samples every 10 feet within the screened interval (140-200 feet bgs) 

at PWS well 77-4. Samples were collected using a 1-inch-diameter bladder pump lowered through a 

1.5-inch polyvinyl chloride (PVC) pipe placed to the top of the screen at 140 feet bgs (Ref. 9, p. 29). 

USGS detected PCE, TCE, and cis-1,2-DCE at all five depths; however, the highest concentrations of 

PCE (4.56 μg/L), TCE (3.2 μg/L), and cis-1,2-DCE (1.81 μg/L) were detected in the ground water sample 

from 170 feet bgs (Ref. 9, p. 133). 

Based on isotopes in the samples, USGS concluded that the ground water entering the deeper portion of 

PWS well 77-4 well screen derived from the upper portion of the aquifer. Because isotopes from samples 

collected from the upper portion of the screened interval did not match those in the lower, USGS 

concluded that the flow from the upper portion of the aquifer was not through the well bore for PWS well 

77-4, but was likely occurring from downward leakage through well bores or annular spaces of irrigation, 

commercial, or older supply wells that penetrated both these layers (Ref. 9, p. 16). USGS identified 

numerous wells and test holes in the York area that were leaking (Ref. 15 p. 35). Further, there are no 

known discontinuities that transect the entire 4 mile Target Distance Limit (TDL).
20 

3.1 LIKELIHOOD OF RELEASE

3.1.1 OBSERVED RELEASE

Aquifer Being Evaluated: Interconnected Aquifer 

Chemical Analysis

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

substance or substances in the media significantly above background level. If the background 

concentration is not detected (or is less than the detection limit), an observed release is established when 

the sample result equals or exceeds the detection limit (Ref. 1, p. 51589). None of the background 

samples exhibited any detectable concentration of PCE or TCE. Numerous ground water samples 

collected from public and private drinking water wells have been found to contain VOCs, particularly 

PCE and TCE. Tables 1 and 2, and Table 3 in the Source Identification Section 2.2.1 depict the 

background and release samples used to document an observed release by chemical analysis. Based on 

the background well and release well sample results presented in the Hazardous Substances Associated 

with the Source section tables, observed release criteria have been met.

Attribution

The PCE Southeast Contamination site area has had numerous commercial and industrial operations that 

currently and historically have handled PCE and TCE. Nine such locations were identified during the 

2010 APA conducted by EPA (Ref. 6, pp. 5-6). 

The PCE Southeast contamination was entered into the CERCLIS in May 2010, after an EPA 

Pre-CERCLIS Site Screening report had identified the potential for contamination from industries in the 

area (Ref. 4, pp 6-7). The Pre-CERCLIS sampling identified VOCs - including PCE and TCE - in five 

private wells. These wells were located within 0.25 mile north or south of E. Nobes Road, between 

S. Iowa Avenue in southeastern York and Road N, located about 0.75 mile east of the York city limits. 

The wells associated with another site, the York PCE site, are about 0.4-1.4 miles east of the 

contaminated wells associated with the Southeast York Groundwater site. The investigation areas for the 

two sites overlapped along E. Nobes Road (Road 12). Figure 2 in Appendix A of Reference 4 presents an 

overview of these approximate site areas (Ref. 4, p. 67). 

PCE is commonly used as a dry cleaning solvent or in metal degreasing, and contamination at both sites 

likely derived from the same general area—commercial or industrial areas of York, located about 0.5 to 

2 miles northwest (upgradient). TCE is also commonly used in metal degreasing but is also a common 
21 

daughter product of PCE degradation; cis-1,2-DCE and vinyl chloride are common daughter products 

from degradation of TCE. 

EPA requested START to conduct investigations at both sites. Because similar PCE concentrations were 

detected at both the sites, it was uncertain whether the ground water contamination was attributable to 

releases from multiple sources, multiple releases from a single source area, or a combination of the two. 

In April 2011, START collected ground water samples from additional private wells near the York PCE 

site, including one in the area where the two site investigations overlap. Because of the similarity of the 

York PCE site to the Southeast York Groundwater site, direct-push technology (DPT) investigations to 

identify the source areas for the ground water plumes were combined under the Southeast York 

Groundwater site. Comparison of results between the York PCE site and the PCE Southeast 

Contamination site indicate that the plume associated with the former site does not contain TCE, whereas 

the latter site contains pronounced TCE concentrations alongside PCE (Ref. 4, pp. 15, 21-23). On this 

basis, the two sites are considered separate and the PCE Southeast site is the subject of this HRS 

documentation record. 

Hazardous Substances Released: PCE, TCE

Ground Water Observed Release Factor Value: 550 

3.1.2 POTENTIAL TO RELEASE

Not Evaluated. 
22 

3.2 WASTE CHARACTERISTICS

3.2.1 TOXICITY/MOBILITY

Table 7: Toxicity/Mobility Factor Table

Hazardous 

Substance

Source 

No.

Toxicity 

Factor 

Value

Mobility 

Factor 

Value1

Does Haz. Substance 

Meet Observed Release? 

(Y/N)

Toxicity/

Mobility

(Table 3-9) Reference

PCE

TCE

1

1

100

1,000

1

1

Yes

Yes

100

1,000

2, pp. 2-3

2, pp. 4-5

Notes:

1. As per HRS Section 3.2.1.2 (Ref. 1, p. 51681), a mobility factor of 1 is assigned to each hazardous substance that meets the 

criteria for an observed release by chemical analysis. 

Toxicity/Mobility Factor Value: 1,000

(Ref. 1, Table 3-9)

3.2.2 HAZARDOUS WASTE QUANTITY

Table 8: Source Hazardous Waste Quantity

Source No. Source Type Source Hazardous Waste Quantity

1 Ground Water Plume with no 

identified Source

> 0, but unknown

The HRS states that if the hazardous constituent quantity is not adequately determined for one or more 

sources then assign a factor value of 100 if any target for that migration pathway is subject to Level I or 

Level II (Ref. 1, Section 2.4.2.2). As there are Level I targets for this pathway (see Section 3.3 of this 

document), 100 will be assigned as the hazardous waste quantity factor value.

Sum of Values: > 0 

Hazardous Waste Quantity Factor Value: 100

(Ref. 1, Table 2-6

3.2.3 WASTE CHARACTERISTICS FACTOR CATEGORY VALUE

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

multiplied by the highest toxicity/mobility value of 1,000 for TCE, resulting in a product of 100,000 

(1.0E+05). Based on this product, a waste characteristics factor value (WCFV) of 18 is assigned from 

Table 2-7 of the HRS (Ref., Section 2.4.3.1). 

Toxicity/Mobility Factor Value: 1,000

Hazardous Waste Quantity Factor Value: 100

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

Waste Characteristics Factor Category Value: 18

(Table 2-7)
23 

3.3 TARGETS

3.3.1 NEAREST WELL

The following well contains contamination that meets the observed release criteria, and the PCE 

concentration is above the health-based benchmark of 5 μg/L (MCL/MCLG) (See Section 3.1.1 of this 

document; Refs. 1, Table 2-3, 3-10; 2, p. 9). 

Well ID: 5105-17

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

Nearest Well Factor Value: 50

(Ref. 1, Table 3-11; Section 3.1.1 of this document) 

3.3.2 POPULATION

3.3.2.1 Level of Contamination

3.3.2.2 Level I Targets (concentrations associated with Level I targets are presented in Section 3.1.1

of this document)

A Level I sample is defined as a drinking water sample with concentration of a hazardous substance such 

as PCE and TCE that meets the criterion of an observed release at or above the hazardous substance’s 

drinking water benchmark (Ref. 1, Section 2.5.1). Health-based benchmarks for the ground water 

migration pathway include the maximum contaminant level (MCL), the cancer risk screening 

concentration (CRSC), and the Non Cancer Risk screening concentration (NCRSC) (Ref. 1, Table 3-10). 

The EPA has set the following health-based benchmarks for TCE and PCE: 

• For PCE, MCL is 5 μg/L, CRSC is 32 μg/L, and NCRSC is 94 μg/L (Ref. 2, pp, 2, 3).

• For TCE, MCL is 5 μg/L, CRSC is 1.0 μg/L, and NCRSC is 7.8 μg/L (Ref. 2, pp, 4, 5) 

The following targets obtain drinking water from wells that contained one or more analytes at 

concentrations that meet the observed release criteria and are above health-based benchmarks (Ref. 1, 

Table 2-3, Table 3-10, and Section 3.1.1). 
24 

Table 9: Level I Samples and Targets

Laboratory 

Sample Number2

Hazardous 

Substance

Hazardous Substance 

Concentration (μg/L)

Population 

Served1 Aquifer Reference

5349-1 PCE

TCE

46

4.9

2.25 1 Ref. 5, pp. 39, 67-68, 

116, 120; 10, pp. 1-2

5432-1 PCE

TCE

6.1

2.0

2.25 1 Ref. 4, pp. 26, 69, 

124, 166, 299, 

304-305; 10, pp. 1-2

5432-2 PCE

TCE

21

8.0

2.25 1 Ref. 4, pp. 26, 69, 

124, 167, 299, 

304-305; 10, pp. 1-2

5432-3 PCE

TCE

8.2

0.89

2.25 1 Ref. 4, pp. 26, 69, 

124, 168, 299, 

304-305; 10, pp. 1-2

5432-4 PCE

TCE

11

1.5

2.25 1 Ref. 4, pp. 26, 69, 

124, 169, 299, 

304-305; 10, pp. 1-2

5432-9 PCE

TCE

12

3.8

2.25 1 Ref. 4, pp. 26, 69, 

124, 174, 299, 

308-309; 10, pp. 1-2

5105-3 PCE

TCE

12

5.9

2.25 1 Ref. 6, pp. 9, 44, 

75-76; 10, pp. 1-2 

5105-17 PCE

TCE

30

0.88

2.25 1 Ref. 6, pp. 10, 5; 10, 

pp. 1-28

5105-18 PCE

TCE

22

1.4

2.25 1 Ref. 6, pp. 10, 59; 10, 

pp. 1-2

5105-19 PCE

TCE

22

2.1

2.25 1 Ref. 6, pp. 10, 60; 10, 

pp. 1-2

Notes:

1 The average persons per household for the City of York, Nebraska has been used (Ref. 10, pp. 1-2). 2 See Figures 1 and 2 for location of samples included in Table 9.

μg/L Micrograms per liter

Sum of Population Served by Level I Wells: 22.5 

Sum of Population Served by Level I Wells: 22.5

Sum of Population Served by Level I Wells x 10: 225.00

Level I Concentrations Factor Value: 225.00

3.3.2.3 Level II Targets (concentrations associated with Level II targets are presented in 

Section 3.1.1) 

The following targets obtain drinking water from wells that contained one or more analytes at 

concentrations that meet the observed release criteria and are not above an HRS health-based benchmark 

(Ref. 1, Table 2-3, Table 3-10, and Section 3.1.1). 
25 

Table 10: Level II Samples and Targets

Sample ID 

Number or 

Well Number

Hazardous 

Substance

Hazard

Substance 

Concentration 

(μg/L)

Population 

Served Aquifer Reference

77-4 PCE 4.56 425a 2 Ref. 9, pp. 23, 133; 17, pp. 1-2

5105-1 PCE

TCE

0.59

0.50 U

2.25b 1 Ref. 6, pp. 9, 42, 75-76; 10, pp. 1-2

Notes:

a Based on a population of 8,081 served by 19 active PWS wells (denoted as “A” in the referenced database), a 

population of 425 was assigned to each well. The two emergency use wells are included in the 19 active wells (Ref. 4, 

p. 50; 17, p. 2-3). 

b The average persons per household for the City of York, Nebraska has been used (Ref. 10, pp. 1-2). 

c See Figures 1 and 2 for location of samples included in Table 10.

ID Identification

Sum of Population Served by Level II Wells: 427.25 

Sum of Population Served by Level II Wells: 427.25

Sum of Population Served by Level II Wells x 1: 427.25

Level II Concentrations Factor Value: 427.25

3.3.2.4 Potential Contamination

Not Scored. 

3.3.3 RESOURCES

Not Scored. 

3.3.4 WELLHEAD PROTECTION AREA

A designated Wellhead Protection Area for the York public water supply system has been mapped within 

the 4-mile target distance limit (Ref. 18, pp. 1-2). The maps provided in Reference 18 are based on the 

Wellhead Protection Area Based on 20-year Time-of-Travel. In accordance with Section 3.3.4 of 

Reference 1, because a source with a ground water containment factor value greater than 0 lies within or 

above the designated Wellhead Protection Area, a value of 20 is assigned and entered below and on line 

10 of HRS Table 3-1. 

Wellhead Protection Area Factor Value: 20