September 2011 

HRS DOCUMENTATION RECORD—REVIEW COVER SHEET

Name of Site: SEAM MASTER INDUSTRIES

Contact Person: Karen Jurist, EPA Region 9 (415) 972-3219 

Site Investigation: Karen Jurist, EPA Region 9 (415) 972-3219 

Documentation Record: Amanda K.C. Reilly, Weston Solutions, Inc. (541) 593-3800 

Pathways, Components, or Threats Not Scored

Surface Water Pathway 

The surface water pathway was not scored because there are no surface water intakes, fisheries, 

or sensitive environments associated with the Los Angeles River downstream of the site. The 

Los Angeles River is located approximately 650 feet east of the site and empties into San Pedro 

Bay approximately 13 miles downstream of the site (Ref. 21, Plate 1; Ref. 23). The Los Angeles 

River is highly modified, having been lined with concrete along a majority of its length by the 

U.S. Army Corps of Engineers in the 1950s. Flows are dominated by urban runoff and tertiarytreated effluent from several municipal wastewater treatment plants (Ref. 15, p. 1, 3). 

Soil Exposure Pathway

The soil exposure pathway was not scored because there are currently no known resident 

individuals, sensitive environments, or resources on or within 200 feet of sources at the site. In 

addition, the majority of the properties are covered in pavement and/or buildings. The Seam 

Master business is currently operating and workers are present onsite (Ref. 24). However, 

scoring the soil exposure pathway does not affect the listing decision. 

Air Migration Pathway

The air pathway was not scored because there is no documented observed release to the 

atmosphere, and scoring the potential to release to air would not likely contribute significantly to 

the overall site score. 
September 2011 

1

HRS DOCUMENTATION RECORD

Name of Site: SEAM MASTER INDUSTRIES

EPA ID#: CAN000905902 

EPA Region: 9 

Date Prepared: September 2011 

Street Address of Site*: 5211 Southern Avenue 

City, County and State: South Gate, Los Angeles County, California 90280 

Topographic Map: South Gate, California USGS 7.5-Minute Quadrangle (Ref. 3) 

Latitude: 33o

 56’ 46.24” North Longitude: 118o 10’ 36.92” West (Ref. 23) 

Latitude/Longitude Reference Point: The latitude and longitude were measured from 

sampling location SM-7, a contaminated soil location (Figure A-3; Ref. 3; Ref. 23). 

SCORES

Air Pathway = Not scored 

Ground Water Pathway = 100.00 

Soil Exposure Pathway = Not scored 

Surface Water Pathway = Not scored 

HRS SITE SCORE = 50.00

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

the general area where 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 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. 
September 2011 

2

HAZARD RANKING SYSTEM

SUMMARY SCORESHEETS 

SITE NAME: SEAM MASTER INDUSTRIES 

CITY/COUNTY/STATE: South Gate, Los Angeles County, California 

EPA ID #: CAN000905902 

EVALUATOR: Amanda K. C. Reilly DATE: September 2011

 S S2

Ground Water Migration Pathway Score (Sgw) 100.00 10,000 

Surface Water Migration Pathway Score (Ssw) Not scored Not scored 

Soil Exposure Pathway Score (Ss) Not scored Not scored 

Air Migration Pathway Score (Sa) Not scored Not scored 

Sgw

2

 +Ssw2 + Ss

2

 + Sa

2

 XXXXXXX 10,000 

(Sgw

2

 +Ssw2 + Ss

2

 + Sa

2

) / 4 XXXXXXX 2,500 

SQRT ((Sgw

2

 +Ssw2 + Ss

2

 + Sa

2

) / 4) XXXXXXX 50.00 

SQRT = square root 
September 2011 

3

TABLE 3-1: GROUND WATER MIGRATION PATHWAY SCORESHEET

Likelihood of Release to an Aquifer Maximum Value Value Assigned

 1. Observed Release 550 550

 2. Potential to Release 

 2a. Containment 10 

 2b. Net Precipitation 10 

 2c. Depth to Aquifer 5 

 2d. Travel Time 35 

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

 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 10

 6. Waste Characteristics 100 18

Targets

 7. Nearest Well 50 18

 8. Population 

 8a. Level I Concentrations b 0

 8b. Level II Concentrations b 0

 8c. Potential Contamination b 1,504

 8d. Population (lines 8a + 8b + 8c) b 1,504

 9. Resources 5 0

10. Wellhead Protection Area 20 0

11. Targets (lines 7 + 8d + 9 + 10) b 1,522

GROUND WATER MIGRATION SCORE FOR AN AQUIFER 

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

GROUND WATER MIGRATION PATHWAY SCORE 

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

all aquifers evaluated)c 100 100 a

Maximum value applies to waste characteristics category. 

b

Maximum value not applicable. 

c

Do not round to nearest integer.
September 2011 

4

Reference 

Number Description of the Reference 

1 

Hazard Ranking System (HRS); Final Rule, 14 December 1990, Vol. 55, No. 

241. 3 p (excerpts) (A complete copy of the HRS Final Rule is also available 

at http://www.epa.gov/superfund/sites/npl/hrsres/index.htm). 

2 

U.S. Environmental Protection Agency (EPA), Superfund Chemical Data 

Matrix (SCDM) Methodology, January 2004. 49 p. (excerpts) (A complete 

copy of the SCDM is available at available at 

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

3 

U.S. Department of the Interior, U.S. Geological Survey, South Gate 

Quadrangle, California-Los Angeles County 7.5 Minute series Topographical 

Map, Photorevised 1981. 1 p. 

4 Weston Solutions, Inc., Preliminary Assessment/Site Inspection Report, 

Seam Master Industries, South Gate, California, May 8, 2003. 787 p. 

5 

U.S. Environmental Protection Agency, Envirofacts Warehouse CERCLIS 

query results for the Seam Master Industries site (CAN000905902), 

http://www.epa.gov/enviro/html/cerclis/cerclis_query.html, accessed 

November 2, 2010. 2 p. 

6 

Los Angeles County Assessor, Detailed Parcel Information, Assessor ID No.: 

6222-003-010, http://maps.assessor.lacounty.gov, accessed November 2, 

2010. 2 p. 

7 Los Angeles County Assessor, Parcel Map, Assessor ID No.: 6222-003-010, 

http://maps.assessor.lacounty.gov, 2003, accessed November 2, 2010. 1 p. 

8 County of Los Angeles, Department of Health Services, Hazardous Waste 

Control Program, Inspection, Seam Master Industries, January 18, 1985. 2 p. 

9 County of Los Angeles, Department of Health Services, Hazardous Waste 

Control Program, Inspection, Seam Master Industries, April 18, 1986. 1 p. 

10 County of Los Angeles, Department of Health Services, Order to Company, 

Seam Master Industries, April 18, 1986. 1 p. 

11 Weston Solutions, Inc., Sampling and Analysis Plan, Seam Master Industries, 

September 2002. 68 p. 

12 

U.S. Environmental Protection Agency (EPA), Superfund Chemical Data 

Matrix (SCDM) Interim Revised Values, October 23, 2006. 1 p. (A 

complete copy of the SCDM is available at 

http://www.epa.gov/superfund/sites/npl/hrsres/tools/scdm.htm) 
September 2011 

5

13 

Rice, Anitra B. and Reilly, Amanda K.C., Weston Solutions, Inc., Telephone 

conversation with Ron Hernandez, City of South Gate, recorded on contact 

report, January 4, June 22, 2011 and August 22, 2011. 2 p. 

14 

Jurist, Karen, U.S. Environmental Protection Agency Region 9, Photographic 

Documentation and Observations Report, Seam Master Industries, February 

22, 2011. 6 p. 

15 

Mullin, Mike, “Splash” Stormwater Program Newsletter, City of Los 

Angeles, Los Angeles River Characterization Study Underway, Fall 2000. 4 

p. 

16 

U.S. Environmental Protection Agency, Envirofacts Warehouse CERCLIS 

query results for the Cooper Drum Co. site (CAD055753370), 

http://www.epa.gov/enviro/html/cerclis/cerclis_query.html, accessed March 

28, 2011. 3 p. 

17 

Innovative Technical Solutions, Inc., Cooper Drum Company Superfund Site 

Remedial Design Technical Memorandum for Field Sampling Results, 

Addendum No. 4, February 26, 2010. 451 pages. 

18 

Rice, Anitra B. and Reilly, Amanda K.C., Weston Solutions, Inc., Telephone 

conversation with Martin Gonzalez, Walnut Park Mutual Water Company, 

recorded on contact, October 29, 2010 June 30, 2011, and August 18, 2011. 1 

p. 

19 

Rice, Anitra B. and Reilly, Amanda K.C., Weston Solutions, Inc., Telephone 

conversation with Bob Rohlf, Maywood Mutual Water Company #3, 

recorded on contact report, December 2, 2010, and August 24, 2011. 1 p. 

20 

California Department of Water Resources, California’s Groundwater 

Bulletin 118, Coastal Plain of Los Angeles Groundwater Basin, Central 

Subbasin, February 27, 2004. 6 p. (excerpts) 

21 

State of California, Department of Water Resources, Southern District, 

excerpts of Bulletin No. 104, Planned Utilization of the Ground Water Basins 

of the Coastal Plain of Los Angeles County, Appendix A, Ground Water 

Geology, June 1961. 207 p. (including Plates 1, 2, 3A, 3B, 4, 5, 6A, 6B, 6E 

and Table 1). (excerpts). 

22 URS Group, Inc., Copper Drum Company Remedial Investigation Feasibility 

Study Report Volume 1, May 15, 2002. 1,087 p. 

23 Google Earth, 33o

 56’ 46.24” N, 118o 10’ 36.92” W, California, 

http://earth.google.com/, July 6, 2011. 1 p. 

24 Seam Master, www.seammaster.com, accessed June 30, 2011. 2 p. 
September 2011 

6

25 Jurist, Karen, U.S. EPA Region IX, Telephone Conversation with Jose 

Molina, City of Lynwood Public Works, , May 25, 2011. 1 p. 

26 KAP Technologies, Inc., SDG Narrative, Case No: 38516, SDG No: Y4W26, 

June 4, 2009. 1,546 p. 

27 KAP Technologies, Inc., SDG Narrative, Case No: 38516, SDG No: Y4W42, 

June 2, 2009. 1,536 p. 

28 Reilly, Amanda K.C., Weston Solutions, Inc., Memorandum Re: Sample 

Quantitation Limits, June 29, 2011. 5 p. 

29 Geology Dictionary, http://geology.com/dictionary/glossary-a.shtml, 

accessed June 30, 2011. 2 p. 

30 

U.S. Environmental Protection Agency, Envirofacts Warehouse CERCLIS 

query results for the Jervis B. Webb Co. site (CAD008339467), 

http://www.epa.gov/enviro/html/cerclis/cerclis_query.html, accessed June 30, 

2011. 1 p. 

31 

National Institute of Environmental Health Sciences, In Situ Bioremediation 

of TCE, Superfund Research Program, Enhancing and Monitoring the Rates 

of Microbial Transformation of Chlorinated Solvents in Anaerobic 

Groundwater,

http://www.niehs.nih.gov/research/supported/srp/products/products2_s1_s2.c

fm, accessed June 30, 2011. 3 p. 

32 Reilly, Amanda K.C., Weston Solutions, Inc., Memorandum Re: Reference 

21 supplemental maps, August 23, 2011. 5 p. 
September 2011 

7

ACRONYM LIST 

AST Aboveground Storage Tank 

bgs below ground surface 

CERCLIS Comprehensive Environmental Response, Compensation, and Liability 

Information System 

CPT Cone Penetrometer Test 

DCA Dichloroethane 

DCE Dichloroethylene 

DHS County of Los Angeles, Department of Health Services 

DWR State of California Department of Water Resources, Southern District 

EPA United States Environmental Protection Agency 

HRS Hazard Ranking System 

ug/kg micrograms per kilogram 

ug/l micrograms per liter 

NOV Notice of Violation 

PA/SI Preliminary Assessment/Site Inspection 

PCE Tetrachloroethylene or Tetrachloroethene 

RWQCB Regional Water Quality Control Board 

Seam Master Seam Master Industries 

TCA Trichloroethane 

TCE Trichloroethylene or Trichloroethene 

USACE United States Army Corps of Engineers 

UST Underground Storage Tank 

VOC Volatile Organic Compound 
September 2011 

8

NOTES TO THE READER

1. Attachment A contains the following maps: 

 — Figure A-1: Seam Master Industries Property Location Map 

 — Figure A-2: Seam Master Industries Facility Layout Map 

 — Figure A-3: Historic Sample Location Map 

 — Figure A-4: Drinking Water Well and Radius Map 
September 2011 

9

SITE DESCRIPTION

The Seam Master Industries (Seam Master) property is located at 5211 Southern Avenue, South 

Gate, Los Angeles County, California (Ref. 3; Ref. 4, p. 8; Ref. 5, p. 1). The property occupies 

approximately 3.85 acres (Ref. 6, p. 1; Ref. 7, p. 1). The Seam Master property location is 

presented in Figure A-1. The source evaluated for this HRS documentation record includes 

VOC-contaminated soil located in the southeastern portion of the property (Ref. 4, p. 12; Figure 

A-3 of the HRS documentation record). The site includes the contaminated soil source and 

releases of volatile organic compounds (VOCs) and associated ground water contamination, 

which pose a hazard to people (see Section 3.1.1). 

Since 1972, the Seam Master facility has been operating as a hot-melt adhesive manufacturing 

company (Ref. 4, p. 38). Inspections conducted by the County of Los Angeles Department of 

Health Services (DHS) in 1985 and 1986 indicate that chlorinated hydrocarbons were used on 

the property (Ref. 8, p. 1, Ref. 9, p. 1). During the 1986 inspection, DHS observed one drum of 

retrograde trichloroethylene (TCE). A notice of violation (NOV) was issued at this time due to 

the illegal storage of retrograde TCE and ordered to properly dispose of the waste (Ref. 9, p. 1; 

Ref. 10, p. 1). 

In 2002, a Preliminary Assessment/Site Inspection (PA/SI) was conducted on the Seam Master 

property. Ground water beneath the property and soils on the property were sampled as part of 

the investigation. Soil samples indicated that TCE and cis-1,2-DCE were detected at 

concentrations above background concentrations (Ref. 4, p. 12). TCE was detected at a 

maximum concentration of 17 ug/kg and cis-1,2-DCE was detected at a maximum concentration 

of 7,100 ug/kg (Ref. 4, p. 434, 452). Ground water samples collected beneath the property 

indicated that TCE and cis-1,2-DCE were present in ground water at concentrations significantly 

above background concentrations. Maximum concentrations of TCE and cis-1,2-DCE detected 

were 17,000 micrograms per liter (ug/l) and 8,000 ug/l, respectively (Ref. 4, p. 13). 

The Cooper Drum Company Superfund Site (EPA ID: CAD055753370) is located at 9316 

Atlantic Avenue in South Gate, California (Ref. 16, p. 1-2). The 3.8 acre facility is located 

approximately 300 feet northwest, and hydraulically upgradient, of the Seam Master property 

(Ref. 17, p. 7, 8, 67, 70-72; Ref. 23). The Cooper Drum facility activities included drum 

reconditioning since the 1940s. Contaminants of concern associated with the Cooper Drum 

facility include TCE and cis-1,2-DCE (Ref. 17, p. 7, 8). The Cooper Drum site was proposed to 

NPL on January 11, 2001 and received its final listing on NPL on June 14, 2001 (Ref. 16, p. 2). 

This HRS documentation record is a listing of releases from the Seam Master site, not from 

Cooper Drum, that are contributing to a TCE- and cis-1,2-DCE-contaminated ground water 

plume (see Sections 2.2 and 3.0 of this HRS documentation record). 

Investigations conducted on the Cooper Drum site involved sampling ground water beneath and 

downgradient of the Seam Master property. Between September 1998 and March 2001, ground 

water sampling was conducted as part of a Phase 2 remedial investigation of the Cooper Drum 

site and depth-discrete ground water samples were collected and analyzed on the Seam Master 
September 2011 

10

property (Ref. 14, p. 4; Ref. 22, p. 20). Analytical results indicated that ground water beneath 

the Seam Master property exhibited maximum concentrations of TCE at 16,000 ug/l and cis-1,2-

DCE at 4,900 ug/l (Ref. 22, p. 122). In addition, in May 2009, all new and existing ground water 

monitoring wells were sampled as part of the continued investigation of the Cooper Drum site. 

Three of the monitoring wells samples were located on or directly down gradient of the Seam 

Master property (Ref. 17, p. 15, 68). Analytical results indicated that ground water directly 

down gradient of the Seam Master property exhibited maximum concentrations of TCE at 46 

ug/l and cis-1,2-DCE at 420 ug/l (Ref. 17, p. 61, 310). 

The Seam Master Industries property is located in an urban area, in which numerous drinking 

water wells are located (Ref. 13; Ref. 18; Ref. 19; Ref. 25; Ref. 32, p. 2; Figures A-1 and A-4 of 

the HRS documentation record). Ground water contamination within the Gaspur aquifer has 

been identified beneath the Seam Master property (Ref. 4, p. 13, 14; Ref. 17, p. 43, 44, 51, 52; 

Ref. 22, p. 70). Eight drinking water wells screened within the Gage and Exposition aquifers are 

located within 4 miles of the source at the site (Ref. 13, p. 2; Ref. 18; Ref. 19; Ref. 21, Plate 3A; 

Ref. 25). These wells were evaluated for potential contamination. Interconnection between the 

Semi-perched, Gaspur, Exposition, and Gage aquifers is established within 2 miles of the source 

at the site and therefore are eligible to be scored as one interconnected aquifer (Ref. 1, Section 

3.0.1.2.1; Ref. 21, Plates 3A, 6A, and 6E; Ref. 32, p. 2; Figures A-1 and A-2 of the HRS 

documentation record). 
September 2011 

11

2.2 SOURCE CHARACTERIZATION

2.2.1 SOURCE IDENTIFICATION

Name of source: Contaminated soil at Seam Master Industries Number of source: 1 

Source Type: Contaminated Soil 

Description and Location of Source (see Figure A-2): 

Source 1 consists of contaminated soils located on the Seam Master property located at 5211 

Southern Avenue in South Gate, Los Angeles County, California (Ref. 4, p. 8, 17; Ref. 5, p. 1; 

Figures A-1 and A-3 of the HRS documentation record). 

Soils contaminated with VOCs associated with the Seam Master operations have been detected 

at concentrations above background in soil samples collected on the property. Samples were 

collected during the October and November 2002 PA/SI sampling event (Ref. 4, p. 12). EPA 

collected soil samples at various depths from seven borings (Ref. 4, p. 12, 13, 34). 

The Seam Master property lies on Los Angeles County Assessor Parcel Number 6222-003-010 

and is approximately 3.85 acres (Ref. 6, p. 1; Ref. 7, p. 1). The property consists of two enclosed 

buildings, one partially enclosed building or shed, a pallet manufacturing area, and a paved 

parking lot. In the northwest portion of the property are three concrete liners that are 

approximately seven feet deep and covered with chicken wire for safety purposes. Reportedly, 

aboveground storage tanks occupied the liners prior to 1972. In the southeastern portion of the 

property is an underground storage tank that has, reportedly, not been utilized by Seam Master. 

In the southeastern portion section of the large enclosed building is a sump (Ref. 4, p. 34, 38). A 

facility layout is presented in Figure A-2. 

During the 2002 PA/SI conducted on the Seam Master property, seven borings were drilled in 

order to collect soil samples. Of the seven borings, one boring was located offsite in order to 

obtain a background sample and six borings were located on the Seam Master property. Boring 

SM-1 was the background sample, and located offsite and north of the Seam Master property, 

borings SM-3 and SM-4 were located adjacent to the concrete liners in the northwest portion of 

the property, boring SM-5 was located south of the concrete liners, and borings SM-7, SM-8 and 

SM-9 were located in the southeastern portion of the property, adjacent to the sump (Ref. 4, p. 

34). Soil samples SM-7-S2 and SM-7-S5 exhibited concentrations of TCE and cis-1,2-DCE 

significantly exceeding background concentrations (Ref. 4, p. 29). Sample locations are 

presented in Figure A-3. 
September 2011 

12

Source Containment

Release to ground water: 

Photographs taken in February 2011 showed that although the Seam Master property is paved, 

the pavement is in poor condition and contains multiple cracks (Ref. 14, p. 2, 3, 5). In addition, 

during the 2002 sampling event, there was no evidence that a liner or engineered cover were 

present at or beneath the ground surface (Ref. 4, p. 48). Precipitation could infiltrate the 

contaminated soil beneath the pavement. Therefore, a containment factor value of 10 is assigned 

(Ref. 1 Sections 2.2.3 and 3.1.2.1 and Table 3-2). 

2.2.2 HAZARDOUS SUBSTANCES ASSOCIATED WITH THE SOURCE

Between October 9 and November 5, 2002, a PA/SI was conducted on the Seam Master 

Industries facility, under the direction of the EPA (Ref. 4, p. 12). Soil sample were collected at 

various depths from seven borings. All samples were analyzed for VOCs using EPA Method 

OLC03.2 (Ref. 4, p. 13). The data were validated by the United States Army Corps of Engineers 

(USACE) Quality Assurance Office (Ref. 4, p. 12, 632-638). 

Soil samples were collected using a 5 gram disposable volumetric sampling device, and were 

collected in triplicate. All samples were sealed using the disposable volumetric sampler and a 

sealable plastic bag. Sample containers were closed as soon as they were filled, immediately 

custody sealed, labeled, and placed on ice for shipment to the laboratory (Ref. 11, p. 27). 

Summarized below is analytical evidence of contamination in soil samples associated with the 

contaminated soil at the Seam Master Industries site. 

Background Concentrations

Source samples were compared to the background sample collected during the respective 

sampling event. During the PA/SI sampling event conducted in 2002, two background samples 

were collected from one location and two sampling depths, 2 feet and 5 feet bgs. Samples SM-1-

S2 and SM-1-S5 were collected from the adjacent west property (Ref. 4, p. 34). 

Sample ID Sampling Date Hazardous 

Substance 

Concentration 

(ug/kg) 

CRQL 

(ug/kg) References 

TCE 5.4 U 5.4 SM-1-S2 10/29/2002 cis-1,2-DCE 5.4 U 5.4 

Ref. 4, p. 633, 

641, 653 

TCE 5.4 U 5.4 SM-1-S5 10/29/2002 cis-1,2-DCE 5.4 U 5.4 

Ref. 4, p. 633, 

641, 657 

Notes:

CRQL: Contract Required Quantitation Limit 

ug/kg: micrograms per kilogram 

U: The analyte was analyzed for but was not detected above the level of the reported contract required quantitation limit (Ref. 4, p. 634) 
September 2011 

13

TCE: Trichloroethylene 

DCE: Dichloroethene 

Source Samples

Between October 9 and November 5, 2002, a PA/SI was conducted on the Seam Master 

Industries facility, under the direction of the EPA (Ref. 4, p. 12). A total of 14 soil samples were 

collected from 7 locations at various depths ranging from 2 feet to 10 feet bgs (Ref. 4, p. 34, 48). 

Samples SM-7-S2 and SM-7-S5 were collected from one location at two sampling depths, 2 feet 

and 5 feet bgs, and TCE and 1,2-cis-DCE were detected above background concentrations (Ref. 

4, p. 29). 

Sample ID Sampling Date Hazardous 

Substance 

Concentration 

(ug/kg) 

CRQL 

(ug/kg) References 

TCE 7.5 6.5 SM-7-S2 10/30/2002 cis-1,2-DCE 6,100 300 

Ref. 4, p. 373, 

410, 424, 633 

TCE 17 5.5 SM-7-S5 10/30/2002 cis-1,2-DCE 7,100 260 

Ref. 4, p. 373, 

434, 452, 633 

Notes:

CRQL: Contract Required Quantitation Limit 

ug/kg: micrograms per kilogram 

TCE: Trichloroethylene 

DCE: Dichloroethene 
September 2011 

14

2.4.2 HAZARDOUS WASTE QUANTITY

Tier A: Hazardous Constituent Quantity - Not Evaluated (NE)

The information available is not sufficient to meaningfully evaluate Tier A, hazardous 

constituent quantity; therefore it is not possible to adequately determine a hazardous constituent 

quantity for Source 1 (Ref. 1, Section 2.4.2.1.1). Scoring proceeds to the evaluation of Tier B, 

Hazardous Wastestream Quantity (Ref. 1, Sections 2.4.2.1.1 and 2.4.2.1.2). 

Hazardous Constituent Quantity Value: NE

Tier B: Hazardous Wastestream Quantity- Not Evaluated (NE)

The information available is not sufficient to meaningfully evaluate Tier B, hazardous 

wastestream quantity; therefore it is not possible to adequately determine a hazardous 

wastestream quantity for Source 1 (Ref. 1, Section 2.4.2.1.2). Scoring proceeds to the evaluation 

of Tier C, Volume (Ref. 1, Sections 2.4.2.1.2 and 2.4.2.1.3). 

Hazardous Wastestream Quantity Value: NE

Tier C: Volume

The information available is not sufficient to meaningfully evaluate Tier C, volume; therefore it 

is not possible to adequately determine a volume for Source 1 (Ref. 1, Section 2.4.2.1.3). 

Scoring proceeds to the evaluation of Tier D, Area (Ref. 1, Sections and 2.4.2.1.3 and 2.4.2.1.4). 

Volume Assigned Value: 0

Tier D: Area

The area of contaminated soil is unknown, but greater than 0. Analytical results of the 2002 soil 

sampling effort indicate the presence of contaminated soil in the southeastern portion of the 

property (boring SM-7) (Ref. 1, Section 2.4.2.1.4; Ref. 4, p. 17; Figure A-3 of the HRS 

documentation record). 

Area Assigned Value: >0
September 2011 

15

Source Hazardous Waste Quantity Value

According to the Hazard Ranking System (HRS), the highest of the values assigned to the source 

for hazardous constituent quantity (Tier A), hazardous wastestream quantity (Tier B), Volume 

(Tier C), and Area (Tier D) should be assigned as the source hazardous waste quantity value 

(Ref. 1, Section 2.4.2.1.5). 

Tier Evaluated Source 1 Values

A NE 

B NE 

C 0 

D >0* 

Note:

* Value selected for the source hazardous waste quantity value, according to the HRS. 

NE Not Evaluated. 

Source Hazardous Waste Quantity Value: >0
September 2011 

16

SITE SUMMARY OF SOURCE DESCRIPTIONS

Containment Source 

No.

Source Hazardous 

Waste Quantity 

Value

Ground 

Water

Surface 

Water Gas Air Particulate

1 >0 10 NE NE NE 

TOTAL >0 

Notes: 

NE = Not Evaluated. 
September 2011 

17

POSSIBLE SOURCES NOT SCORED 

• Three concrete liners/former aboveground storage tanks (ASTs). The concrete liners are 

located in the northwest corner of the Seam Master property (Ref. 4, p. 9, 38). The liners 

are approximately 7 feet deep and covered with chicken wire for safety purposes. During 

the 2002 PA/SI conducted on the Seam Master property, nothing was observed inside the 

concrete liners. However, the business manager stated that ASTs were inside the liners 

prior to 1972, when a screw manufacturer operated on the property (Ref. 4, p. 38, 46, 47). 

• White holding tanks. During the 2002 PA/SI conducted on the Seam Master property, 

three aboveground white holding tanks were observed along the eastern portion of the 

property. They were currently not in use (Ref. 4, p. 44). However, previous businesses 

may have utilized the tanks for hazardous substances. 

• Underground storage tank. The underground storage tank (UST) is located in the 

southeastern portion of the property (Ref. 4, p. 9, 38). As of 2002, the UST was not used 

for Seam Master operations and the business manager suspected that it was utilized by 

prior tenants for gasoline products (Ref. 4, p. 9, 38). 
September 2011 

18

3.0 GROUND WATER MIGRATION PATHWAY

3.0.1 GENERAL CONSIDERATIONS

The Seam Master facility is located in the Central Basin Pressure Area of the Central Basin of 

the Los Angeles Coastal Plain (Ref. 20, p. 1; Ref. 21, pp. 130, 166, Plate 2; Ref. 22, p. 32, 33; 

Ref. 32, p. 2; Figure A-1 of the HRS documentation record). Ground water is found in the 

Recent Alluvium, Lakewood Formation, and San Pedro Formation (Ref. 21, p. 188; Ref. 22, p. 

33). Geologic materials in the unsaturated zone of the Recent Alluvium, between ground surface 

and the top of the Lakewood Formation are primarily composed of sandy silts to silty clays and 

have been described as correlating with the Bellflower Aquiclude (Ref. 17, p. 8, 101 - 103; Ref. 

21, p. 168, 169). An aquiclude is defined as a subsurface rock, soil, or sediment unit that does 

not yield useful quantities of water (Ref. 29, p. 1). Interbedded within the Bellflower Aquiclude 

are discontinuous lenses of silty-sands that may allow for the presence of one or more perched 

aquifers. The groundwater flow direction within these perched aquifers is sensitive to lithologic 

variations, groundwater extraction, and/or surface water recharge (Ref. 17, p. 8, 10; Ref. 20, p. 1-

3; Ref. 21, p.168) 

In the South Gate area, shallow ground water occurs at a depth of approximately 45 feet bgs, 

with a ground water flow direction to the south or southeast. Shallow ground water beneath the 

Seam Master property is expected to be similar to the nearby Cooper Drum Company property, 

where it occurs within or is controlled by the near surface Bellflower Aquiclude, which 

incorporates the Semi-perched Aquifer (Ref. 17, p. 8, 9; Ref. 22, p. 18, 19). In the vicinity of the 

facility, the Lakewood Formation, which immediately underlies the Recent Alluvium, consists of 

the Gaspur Aquifer, Exposition Aquifer, an unnamed aquiclude, and the Gage Aquifer. Ground 

water flow within the Gaspur Aquifer is generally to the south beneath the Seam Master facility 

(Ref. 17, p. 70 – 72). Although data are not adequate to document ground water flow within the 

Exposition and Gage aquifers, it is assumed that the flow direction would be generally towards 

the south, in the direction of the Pacific Ocean (Ref. 20, p. 2). The San Pedro Formation, which 

underlies the Lakewood Formation, consists of the Hollydale, Jefferson, Lynwood, Silverado, 

and Sunnyside Aquifers with intervening aquitards [Ref. 21, p. 182, 183, 184, Plate 6A 

(Geologic Section B-B’); Figures A-1 and A-2 of the HRS documentation record]. The main 

hydrogeologic features identified beneath the Seam Master facility include the Bellflower 

Aquiclude, the Semi-perched Aquifer, and the Gaspur, Exposition, and Gage Aquifers. These 

latter units constitute a shallow aquifer and two deeper aquifers, respectively. (Ref. 17, p. 8; Ref. 

21, p. 182; Ref. 22, p. 19; Ref. 32, p. 2; Figures A-1 and A-2 of the HRS documentation record). 

It appears that the Lakewood and San Pedro formations may not be in hydraulic continuity 

within 2 miles of the Seam Master facility [Ref. 21, p. 166, Plates 3A, 6A (Geologic Section BB’), 6E (Geologic Section L-L’); Ref. 32, p. 1-2]. In the late 1950s, the State of California 

Department of Water Resources, Southern District (DWR), compiled 50 geologic sections for the 

Los Angeles Coastal Plain (Ref. 21, p. 2, 3, 20). The geologic sections were compiled in order to 

complete a geologic picture of the Coastal Plain of Los Angeles County. These sections are 
September 2011 

19

based on electric logs and drillers’ logs from approximately 200 oil wells and 3,500 water wells 

(Ref. 21, p. 20). Examination of DWR geologic sections B-B’ and L-L’ suggests that the 

lowermost aquifer in the Lakewood Formation (i.e., the Gage aquifer) is separated from the 

uppermost aquifer in the San Pedro Formation (i.e., the Hollydale aquifer) by a laterally 

continuous lower permeability layer in the vicinity of the property [Ref. 21, p. 166, Plates 3A, 

6A (Geologic Section B-B’), 6B (Geologic Section C-C’)]. Interconnections between the Semiperched, Gaspur, Exposition, and Gage aquifers is established within 2 miles of the source at the 

site and therefore are eligible to be scored as one interconnected aquifer (Ref. 1, Section 

3.0.1.2.1; Ref. 21, Plates 3A, 6A, and 6E; Ref. 32, p. 2; Figures A-1 and A-2 of the HRS 

documentation record). Since data are not adequate to establish aquifer interconnection between 

the Lakewood and San Pedro formations within 2 miles of the Seam Master facility (see 

preceding paragraph) and an observed release is documented to the Semi-perched, Gaspur, 

Exposition, and Gage aquifers [see Section 3.1.1 (Observed Release) of this HRS documentation 

record], the following hydrogeologic discussion is limited to those strata that have been 

identified in the Recent Alluvium and Lakewood Formation. 

- Stratum 1: Bellflower Aquiclude and Semi-Perched Aquifer

The Bellflower Aquiclude extends from the surface to a depth of approximately 55 to 70 feet bgs 

and consists of sandy silts, clayey silts, and lesser amounts of silty clay. The semi-perched 

aquifer is present within the Bellflower Aquiclude. Water levels are generally found in a 

laterally continuous 5-foot-thick silty/sandy unit at approximately 35 to 40 feet bgs, which is 

underlain by finer materials of the Bellflower Aquiclude (Ref. 17, p. 8; Ref. 22, p. 34, 35). The 

Bellflower Aquiclude does not restrict ground water movement between the strata composing the 

aquifer (Ref. 17, p. 52, 61,101 - 103, 165, 166; Ref. 21, pp. 62, 63, 72, 73, 77, 168, 169, 184, 

185). 

- Stratum 2: Gaspur Aquifer 

The shallow aquifer is represented by the Gaspur Aquifer which underlies the Bellflower 

Aquiclude and extends to a depth of approximately 110 to 120 feet bgs. The Gaspur Aquifer is 

of fluvial origin and occurs within an ancestral Los Angeles River channel. The Gaspur Aquifer 

consists of sandy units varying from very fine to medium and coarse and to a lesser extent finer 

units comprising silty sand and sandy silt. Water level in the Gaspur Aquifer is generally at a 

depth that corresponds to the Lower Bellflower Aquiclude, suggesting the Gaspur Aquifer is a 

semi-confined aquifer (Ref. 17, p. 8, 101 - 103; Ref. 22, p. 34). The horizontal flow direction in 

the Gaspur Aquifer is toward the south (Ref. 17, p. 9). 

- Stratum 3: Exposition Aquifer 

The Exposition Aquifer, which underlies the Gaspur Aquifer, begins at a depth of approximately 

110 to 120 feet bgs (Ref. 17, p. 8). The maximum thickness of the Exposition Aquifer is 100 

feet and is reportedly related to the ancestral Los Angeles River drainage system. Materials 
September 2011 

20

range in size from coarse gravels to clay, with the fine deposits separating the lenticular sandy 

and gravelly beds. The upper coarse members of the Exposition appear to have been either 

eroded and backfilled by the overlying Gaspur Aquifer deposits, or some of the upper members 

were deposited contemporaneously with the formation of the younger Gaspur Aquifer (Ref. 22, 

p. 34). 

- Stratum 4: Unnamed Aquiclude 

Based on DWR Geologic Section B-B’, a lower permeability layer underlies the Exposition 

aquifer beneath the Seam Master facility. It extends from approximately 160 feet bgs to 200 feet 

bgs [Ref. 21, Plates 3A, 6A (Geologic Section B-B’); Figures A-1 and A-2 of the HRS 

documentation record]. 

- Stratum 5: Gage Aquifer 

The Gage aquifer generally consists of fine-grained sand and silty sand in the Central Basin 

Pressure Area (Ref. 21, p. 183, 184). This aquifer underlies the unnamed aquiclude and extends 

from 200 feet bgs to 275 feet bgs beneath the Seam Master facility [Ref. 21, Plates 3A, 6A 

(Geologic Section B-B’)]. 

- Aquifer Interconnection

Interconnection between the Semi-Perched, Gaspur, Exposition, and Gage Aquifers is 

established within 2 miles of Source 1 at the property as follows (Ref. 1, Section 3.0.1.2.1): 

• Contamination has been documented in two monitoring wells (MW-34 and MW-35) 

located directly downgradient of the Seam Master facility (Ref. 17, p. 15, 38, 61, 68, 310, 

311). Monitoring wells MW-34 and MW-35 are screened within the Gaspur Aquifer 

(Ref. 17, p. 8, 38, 51). This supports that the Bellflower Aquiclude and Semi-perched 

Aquifer are interconnected to the underlying formations (i.e., Lakewood Formation) since 

contaminants have passed through to the lower aquifers. 

• An examination of DWR Geologic Sections B-B’ and L-L’ indicates that the Gaspur 

Aquifer is in direct contact with the Exposition Aquifer in the property vicinity (Ref. 21, 

Plates 3A, 6A, and 6E; Ref. 32, p. 2; Figures A-1 and A-2 of the HRS documentation 

record). 

• An examination of DWR Geologic Section B-B’ indicates that the unnamed aquiclude 

between the Exposition and Gage Aquifers is not continuous within 2 miles of the Seam 

Master facility. This aquiclude is shown as pinching out approximately 1,500 feet to the 

west of the property, resulting in a merging of the two aquifers [Ref. 1, Section 3.0.1.2.1; 

Ref. 21, Plates 3A and 6A (Geologic Section B-B’); Ref. 32, p. 2; Figures A-1 and A-2 of 

the HRS documentation record]. 
September 2011 

21

- Aquifer Discontinuities 

An examination of DWR Plate 3A indicate that the Seam Master facility is located between 

Geologic Sections B-B’ and C-C’ that run generally southwest-northeast, and between Geologic 

Sections K-K’ and L-L’ that run generally northwest-southeast (Ref. 21, Plate 3A). An 

examination of Geologic Sections B-B’, C-C’, K-K’ and L-L’ show that there are no aquifer 

discontinuities between the Semi-Perched and Gage aquifers within 4 miles of Source 1 at the 

Seam Master site (Ref. 1, Section 3.0.1.2.2; Ref. 21, Plate 6A, Plate 6B, Plate 6E; Ref. 32, p. 2; 

Figures A-1 and A-2 of the HRS documentation record). 

SUMMARY OF AQUIFER BEING EVALUATED

Aquifer 

No. Aquifer Name

Is Aquifer 

Interconnected with 

Upper Aquifer within 2 

miles? (Y/N/NA)

Is Aquifer 

Continuous 

within 4-mile 

TDL? (Y/N)

Is Aquifer 

Karst? 

(Y/N)

1 

SemiPerched/Gaspur/ 

Exposition/Gage 

Y Y N 

Notes:

Y: Yes 

N: No 

NA: Not applicable 
September 2011 

22

3.1 LIKELIHOOD OF RELEASE

3.1.1 OBSERVED RELEASE

Aquifer Being Evaluated: Semi-Perched/Gaspur/Exposition/Gage 

Chemical Analysis

2000 Investigation Sampling

Between September 1998 and March 2001, ground water sampling was conducted on the Seam 

Master property as part of a Phase 2 remedial investigation of the Cooper Drum site. As part of 

the investigation, cone penetrometer test (CPT) borings were drilled on the Seam Master 

property and depth-discrete ground water samples were collected and analyzed (Ref. 14, p. 4; 

Ref. 22, p. 20). All samples were analyzed for VOCs by gas chromatography/mass spectrometry 

(GC/MS) Regional Analytical Program/non-Contract Laboratory Program low-level volatile 

organics analysis with 25 mL purge (Ref. 22, p. 55, 63, 849, 855). 

Ground water sample locations are shown in Figure A-3 and Reference 22, page 68. 

- Background Concentrations: 

Background levels for site-related VOC hazardous substances are established below based on the 

analytical results from ground water collected from borings CPT-16 and CPT-20. Boring CPT16 was located northwest of the Seam Master property adjacent south to the ELG Metals 

building, upgradient of the Seam Master property production warehouse and raw material 

storage and downgradient of the Copper Drum and Jervis properties. Boring CPT-20 was 

located in the northeast portion of the Seam Master property, upgradient of the Seam Master 

production warehouse and raw material storage and downgradient of ELG Metals (Ref. 22, p. 51, 

68, 83). 

Ground water collected from borings CPT-16 and CPT-20 are used to establish background 

levels for the contaminated ground water sample collected from boring CPT-21 listed below. 

Data are compared to background samples collected during the same sampling event using the 

same methodology. All ground water samples were collected using a drive sampler. The drive 

sampler is driven into undisturbed soil beneath the bottom of a borehole. When at the desired 

depth, the sampler is pulled back approximately one foot to expose the screen on the sampler. 

Depth-discrete ground water samples are collected by lowering a bailer down the sampling 

device, retrieving the bailer and transferring the ground water sample to the sample container 

(Ref. 22, p. 55). The ground water samples presented below were collected at depths between 60 

and 65 feet bgs (Ref. 22, p. 122). 
September 2011 

23

Sample ID 

Sample 

Depth 

(ft bgs) 

Sampling 

Date 

Hazardous 

Substance 

Concentration 

(ug/l) 

CRQL 

(ug/l) References 

TCE 0.5 U 0.5 

CPT-16 60 10/10/2000 

cis-1,2-DCE 0.5 U 0.5 

Ref. 22, p. 

122, 415, 651, 

843, 844, 855, 

849 

TCE 24 0.5 

CPT-20 64 10/9/2000 

cis-1,2-DCE 9 0.5 

Ref. 22, p. 

122, 417, 649, 

847, 848, 849, 

855 

Notes:

CRQL: Contract Required Quantitation Limit 

ft bgs: feet below ground surface 

ug/l: micrograms per liter 

U: The analyte was analyzed for but was not detected above the level of the reported sample quantitation limit 

- Contaminated Samples:

The boring listed below is located downgradient of the source at the Seam Master facility. For 

conservative purposes, the higher concentration background levels from the October 2000 

sampling event (CPT-20) are compared to the October 2000 contaminated sample in order to 

establish a release. Sample locations are presented in Figure A-3 and Reference 22, page 68. 

Sample ID 

Sample 

Depth 

(ft bgs) 

Sampling 

Date 

Hazardous 

Substance 

Concentration 

(ug/l) 

CRQL 

(ug/l) References 

TCE 8,000 0.5 

CPT-21 63 10/9/2000 

cis-1,2-DCE 4,900 0.5 

Ref. 22, p. 

122, 418, 649, 

849, 851, 852, 

855 

Notes:

CRQL: Contract Required Quantitation Limit 

ft bgs: feet below ground surface 

ug/l: micrograms per liter 

2002 Seam Master PA/SI Ground Water Sampling

In 2002, ground water sampling was conducted as part of the PA/SI investigation on the Seam 

Master property. Ground water samples were collected from one monitoring well and five 

borings. All samples were analyzed for VOCs using EPA Method OLM04.2 (Ref. 4, p. 12, 13, 

14). 

Ground water sample locations are shown in Figure A-3 and Reference 4, page 33. 

- Background Concentrations: 

Background levels for site-related VOC hazardous substances are established below based on the 

analytical results from ground water collected from boring SM-1 and monitoring well MW-14. 

Boring SM-1 was located northwest of the Seam Master property on the CEE Sportsware 
September 2011 

24

property, upgradient of the Seam Master property and downgradient of the Cooper Drum and 

Jervis properties. Monitoring well MW-14 is located north of the Seam Master property on the 

ELG Metals property, upgradient of the Seam Master property and downgradient of the Jervis 

property (Ref. 4, p. 8, 33; Ref. 17, p. 68, 70). 

Ground water samples collected from boring SM-1 and monitoring well MW-14 are used to 

establish background levels for the contaminated ground water samples collected from borings 

SM-6-GW and SM-7-GW listed below. Data are compared to background samples collected 

during the same sampling event using similar sampling methodology. Monitoring well MW-14 

was purged at an average rate of approximately 0.3 gallons per minute for 97 minutes using a 

submersible pump. After purging was complete, ground water was sampled using a disposable 

bailer (Ref. 4, p. 13, 14, 50, 51). Boring SM-1 was drilled and when ground water was 

encountered, an in-situ ground water sample was collected using a water sampling device. The 

water sampling device is inserted into undisturbed sediments at the base of the borehole. The 

outer portion of the water sampling device is then retracted to expose a stainless steel screen in 

the water-bearing zone. A stainless steel mini-bailer is lowered into the screen for collection of 

an in-situ ground water sample. All samples were collected into pre-preserved 40-mL vials 

which were immediate capped and inverted to check for air bubbles to ensure zero headspace 

(Ref. 11, p. 27). 

Sample 

ID 

Well 

Screened 

Interval 

(ft bgs) 

Sampling 

Date 

Hazardous 

Substance 

Concentration 

(ug/l) 

CRQL 

(ug/l) References 

TCE 7 0.5 

SM-1-GW 45 – 65 10/29/2002 

cis-1,2-DCE 1 0.5 

Ref. 4, p. 345-

351, 355; Ref. 

11, p. 22 

TCE 58 0.5 

MW-14 30 – 60 11/5/2002 cis-1,2-DCE 330 0.5 

Ref. 4, p. 333-

339; Ref. 17, 

p. 37 

Notes:

CRQL: Contract Required Quantitation Limit 

ft bgs: feet below ground surface 

ug/l: micrograms per liter 

- Contaminated Samples:

The borings listed below are located downgradient of the source at the Seam Master facility. For 

conservative purposes, the higher concentration background levels from the November 2002 

sampling event (MW-14) are compared to the October 2002 contaminated sample in order to 

establish a release. Sample locations are presented in Figure A-3 and Reference 4, page 33. 

Sample 

ID 

Well 

Screened 

Interval 

(ft bgs) 

Sampling 

Date 

Hazardous 

Substance 

Concentration 

(ug/l) 

CRQL 

(ug/l) References 

SM-6-GW 45 – 65 10/29/2002 TCE 1,700 0.5 

Ref. 4, p. 345-

350; 353, 355; 

Ref. 11, p. 22 
September 2011 

25

Sample 

ID 

Well 

Screened 

Interval 

(ft bgs) 

Sampling 

Date 

Hazardous 

Substance 

Concentration 

(ug/l) 

CRQL 

(ug/l) References 

SM-7-GW 45 – 65 10/30/2002 TCE 4,100 0.5 

Ref. 4, p. 345-

350; 353, 355; 

Ref. 11, p. 22 

SM-8-GW 45 – 65 10/29/2002 TCE 4,000 0.5 

Ref. 4, p. 345-

350; 353, 355; 

Ref. 11, p. 22 

TCE 17,000 0.5 

SM-9-GW 45 – 65 10/30/2002 

cis-1,2-DCE 8,000 0.5 

Ref. 4, p. 345-

350; 353, 355; 

Ref. 11, p. 22 

Notes:

CRQL: Contract Required Quantitation Limit 

ft bgs: feet below ground surface 

ug/l: micrograms per liter 

2009 Investigation Sampling

Between May 12 and 19, 2009, all new and existing ground water monitoring wells were 

sampled as part of the continued investigation of the Cooper Drum site. Two of the monitoring 

wells sampled were located directly down gradient of the Seam Master property (Ref. 17, p. 15, 

68). All samples were analyzed for VOCs using EPA Method SOM01.2 (Ref.17, p. 15; Ref. 26, 

p. 1; Ref. 27, p. 1). 

Ground water sample locations are shown in Figure A-3 and Reference 17, page 68. 

- Background Concentrations: 

Background levels for site-related VOC hazardous substances are established below based on the 

analytical results from ground water collected from monitoring wells MW-10 and MW-14. 

MW-10 is located in the southwest portion of the ELG Metals property, upgradient of the Seam 

Master property and downgradient of the Cooper Drum and Jervis properties. Monitoring well 

MW-14 is located north of the Seam Master property on the ELG Metals property, upgradient of 

the Seam Master property and downgradient of the Jervis property (Ref. 17, p. 68, 70). 

Monitoring wells MW-10 and MW-14 are used to establish background levels for the 

contaminated monitoring wells listed below. Background and downgradient monitoring wells 

are screened within the Gaspur aquifer (Ref. 17, p. 43, 44, 51, 52). Data are compared to 

background samples collected during the same sampling event using the same methodology. 

The sampling protocol employed standard low-flow ground water sampling techniques with a 

flow-through cell. The monitoring wells were sampled using 2-inch pumps with disposable 

discharge tubing. All samples were transported in a cooler packed with ice, under chain-ofcustody protocol (Ref. 17, p. 15). 
September 2011 

26

Sample ID 

Well 

Screened 

Interval 

(ft bgs) 

Sampling 

Date 

Hazardous 

Substance 

Concentration 

(ug/l) 

SQL 

(ug/l) References 

TCE 15 0.5 

MW-10 45 – 74.5 5/14/2009 

cis-1,2-DCE 32 2.5 

Ref. 17, p. 37, 

56, 280; Ref. 

26, p. 13, 135, 

158; Ref. 28, 

p. 2 

TCE 0.63 0.5 

MW-14 30 - 60 5/14/2009 

cis-1,2-DCE 3.2 0.5 

Ref. 17, p. 37, 

57, 282; Ref. 

26, p. 13, 198, 

199; Ref. 28, 

p. 2 

Notes:

ft bgs: feet below ground surface 

ug/l: micrograms per liter 

U: The analyte was analyzed for but was not detected above the level of the reported sample quantitation limit 

SQL: Sample Quantitation Limit. The SQLs provided in this table are CLP contract-required quantitation limits (CRQLs) for that analyte 

with any dilution factors, volume adjustments, or percent solids for that analysis taken into account. SQLs were calculated as

follows: 

( ) DF x 

initial (mL) volume

final (mL) volume x L

μg CRQL / SQL ⎟

⎠

⎞ ⎜

⎝

⎛ Lμg =

 Where: 

Final volume (mL) is the final extract volume following sample preparation 

 Initial volume (mL) is the volume of sample used 

 DF is the dilution factor 

- Contaminated Samples:

The wells listed below are located downgradient of the sources at the Seam Master facility. For 

conservative purposes, the higher concentration background levels from the May 2009 sampling 

event (MW-10) are compared to the May 2009 contaminated sample in order to establish a 

release. Well locations are presented in Figure A-3, Reference 17, page 68 and Reference 22, 

page 68. 

Sample ID 

Well 

Screened 

Interval 

(ft bgs) 

Sampling 

Date 

Hazardous 

Substance 

Concentration 

(ug/l) 

SQL 

(ug/l) References 

TCE 46 E 0.5 

MW-34 58 - 68 5/16/2009 

cis-1,2-DCE 420 E 0.5 

Ref. 17, p. 38, 

61, 310; Ref. 

27, p. 12, 306, 

307; Ref. 28, 

p. 2 

MW-35 95 - 105 5/16/2009 TCE 120 5.0 

Ref. 17, p. 38, 

61, 311; Ref. 

26, p. 14, 257; 

Ref. 28, p. 2 

Notes:

E: Concentration exceeds upper level of instrument calibration range (Ref. 17, p. 63) 
September 2011 

27

ft bgs: feet below ground surface 

ug/l: micrograms per liter 

SQL: Sample Quantitation Limit. The SQLs provided in this table are CLP contract-required quantitation limits (CRQLs) for that analyte 

with any dilution factors, volume adjustments, or percent solids for that analysis taken into account. SQLs were calculated as

follows: 

( ) DF x 

initial (mL) volume

final (mL) volume x L

μg CRQL / SQL ⎟

⎠

⎞ ⎜

⎝

⎛ Lμg =

 Where: 

Final volume (mL) is the final extract volume following sample preparation 

 Initial volume (mL) is the volume of sample used 

 DF is the dilution factor 
September 2011 

28

Attribution

The Seam Master property is located at 5211 Southern Avenue, South Gate, Los Angeles 

County, California (Ref. 3; Ref. 4, p. 8; Ref. 5, p. 1). The property occupies approximately 3.85 

acres (Ref. 6, p. 1; Ref. 7, p. 1). The Seam Master property location is presented in Figure A-1. 

Since 1972, the Seam Master property has been operating as a hot-melt adhesive manufacturing 

company (Ref. 4, p. 38). Inspections conducted by the DHS in 1985 and 1986 indicate that 

chlorinated hydrocarbons were used on the property (Ref. 8, p. 1, Ref. 9, p. 1). During the 1986 

inspection, DHS observed one drum of retrograde TCE. A NOV was issued at this time due to 

the illegal storage of retrograde TCE and Seam Master was ordered to properly dispose of the 

waste (Ref. 9, p. 1; Ref. 10, p. 1). 

In the South Gate area, shallow ground water occurs at a depth of approximately 45 feet bgs, 

with a ground water flow direction to the south or southeast. Shallow ground water beneath the 

Seam Master property is expected to be similar to the nearby Cooper Drum Company property, 

where it occurs within or is controlled by the near surface Bellflower Aquiclude, which 

incorporates the semi-perched aquifer (Ref. 17, p. 8, 9; Ref. 22, p. 18, 19). In the vicinity of the 

Seam Master facility, the Lakewood Formation, which immediately underlies the Bellflower 

Aquiclude, consists of the Gaspur aquifer, Exposition aquifer, an unnamed aquitard, and the 

Gage aquifer. Ground water flow within the Gaspur aquifer is generally to the south beneath the 

Seam Master facility (Ref. 17, p. 70 – 72). Although data are not adequate to document ground 

water flow within the Exposition and Gage aquifers, it is assumed that the flow direction would 

be generally towards the south, in the direction of the Pacific Ocean (Ref. 20, p. 2; Ref. 21, p. 

182, 183, 184, Plate 6A (Geologic Section B-B’); Ref. 23; Ref. 32; Figures A-1 and A-2 of the 

HRS documentation record). 

The Cooper Drum site (EPA ID: CAD055753370) is located at 9316 Atlantic Avenue in South 

Gate, California (Ref. 16, p. 1-2). The 3.8 acre facility is located approximately 300 feet 

northwest, and hydraulically upgradient, of the Seam Master property (Ref. 17, p. 7, 67, 70-72; 

Ref. 23). The Cooper Drum facility activities included drum reconditioning since the 1940s. 

Contaminants of concern associated with the Cooper Drum facility include TCE and cis-1,2-

DCE (Ref. 17, p. 7, 8). The Cooper Drum site was proposed to NPL on January 11, 2001 and 

received its final listing on NPL on June 14, 2001 (Ref. 16, p. 2). This HRS documentation 

record is a listing of releases from the Seam Master site, not from Cooper Drum, that are 

contributing to a TCE- and cis-1,2-DCE-contaminated ground water plume (see Sections 2.2 and 

3.0 of this HRS documentation record). 

The Jervis B. Webb Co. site (EPA ID: CAD008339467) is located at 9301 Rayo Avenue in 

South Gate, California (Ref. 30, p. 1). The 3.82 acre facility is located approximately 750 feet 

north, and hydraulically upgradient, of the Seam Master property (Ref. 17, p. 67, 70 – 72; Ref. 

23). Investigations of the Jervis B. Webb Co. site have been conducted by EPA due to TCE and 

PCE ground water contamination. (Ref. 17, p. 21) 

In 2002, a PA/SI was conducted on the Seam Master property. Ground water beneath the 

property and soils on the property were sampled as part of the investigation. Soil samples 

indicated that TCE and cis-1,2-DCE were detected at concentrations above background 
September 2011 

29

concentrations (Ref. 4, p. 12). TCE was detected at a maximum concentration of 7.5 ug/kg and 

cis-1,2-DCE was detected at a maximum concentration of 6,100 ug/kg (Ref. 4, p. 410, 424). 

Photographs taken in February 2011 showed that although a majority of the Seam Master 

property is paved, the pavement is in poor condition and contains multiple cracks (Ref. 14, p. 2, 

3, 5). In addition, during the 2002 sampling event, there was no evidence that a liner or 

engineered cover were present at or beneath the ground surface (Ref. 4, p. 48). Precipitation 

could infiltrate the contaminated soil beneath the pavement. 

Ground water samples collected beneath the property during the 2002 PA/SI indicated that TCE 

and cis-1,2-DCE were present in ground water at concentrations significantly above background 

concentrations. Maximum concentrations of TCE and cis-1,2-DCE detected were 17,000 ug/l 

and 8,000 ug/l, respectively (Ref. 4, p. 13). The maximum contaminant level (MCL) is 5 ug/l for 

TCE and 70 ug/l for cis-1,2-DCE (Ref. 2). Background levels for Seam Master-related VOC 

hazardous substances were established based on the analytical results from ground water 

collected from boring SM-1 and monitoring well MW-14. Boring SM-1 was located northwest 

of the Seam Master property on the CEE Sportsware property, upgradient of the Seam Master 

property and downgradient of the Cooper Drum and Jervis properties. Monitoring well MW-14 

is located north of the Seam Master property on the ELG Metals property, upgradient of the 

Seam Master property and downgradient of the Jervis property (Ref. 4, p. 8, 34; Ref. 17, p. 68, 

70). 

Investigations conducted on the Cooper Drum site involved sampling ground water beneath and 

downgradient of the Seam Master property. In October 2000 a remedial investigation of the 

Cooper Drum site was conducted and depth-discrete ground water samples were collected and 

analyzed on the Seam Master property (Ref. 14, p. 4; Ref. 22, p. 20). Analytical results indicated 

that ground water beneath the Seam Master property exhibited maximum concentrations of TCE 

at 8,000 ug/l and cis-1,2-DCE at 4,900 ug/l (Ref. 22, p. 122). Background levels for Seam 

Master-related VOC hazardous substances were established based on the analytical results from 

ground water collected from borings CPT-16 and CPT-20. Boring CPT-16 was located 

northwest of the Seam Master property adjacent south to the ELG Metals building, upgradient of 

the Seam Master property production warehouse and raw material storage and downgradient of 

the Copper Drum and Jervis properties. Boring CPT-20 was located in the northeast portion of 

the Seam Master property, upgradient of the Seam Master production warehouse and raw 

material storage and downgradient of ELG Metals (Ref. 22, p. 51, 68, 83). 

In May 2009, all new and existing ground water monitoring wells were sampled as part of the 

continued investigation of the Cooper Drum site. Two of the monitoring wells samples were 

located directly down gradient of the Seam Master property (Ref. 17, p. 15, 68). Analytical 

results indicated that ground water directly down gradient of the Seam Master property exhibited 

maximum concentrations of TCE at 46 ug/l and cis-1,2-DCE at 420 ug/l (Ref. 17, p. 61, 310). 

Background levels for Seam Master-related VOC hazardous substances were established based 

on the analytical results from ground water collected from monitoring wells MW-10 and MW14. MW-10 is located in the southwest portion of the ELG Metals property, upgradient of the 

Seam Master property and downgradient of the Cooper Drum and Jervis properties. Monitoring 

well MW-14 located north of the Seam Master property on the ELG Metals property, upgradient 

of the Seam Master property and downgradient of the Jervis property (Ref. 17, p. 68, 70). 
September 2011 

30

The increased concentrations of cis-1,2-DCE in correlation with the decreased concentrations of 

TCE between the 2000/2002 release data and the 2009 release data is due to cis-1,2-DCE being a 

degradation product of TCE (Ref. 31, p. 1). An NOV was issued in 1986 due to the illegal 

storage of TCE. TCE and cis-1,2-DCE are hazardous substances associated with the onsite 

source (Ref. 9, p. 1; Ref. 10, p. 1). 

Ground water samples collected on and downgradient of the Seam Master property establish a 

release to the Gaspur aquifer (Ref. 4, p. 13; Ref. 17, p. 43, 44, 51, 52, 61, 101 – 103, 310; Ref. 

22, p. 70, 122). 

Interconnection between the Semi-Perched, Gaspur, Exposition, and Gage Aquifers is 

established within 2 miles of Source 1 at the property as follows (Ref. 1, Section 3.0.1.2.1): 

• Contamination has been documented in two monitoring wells (MW-34 and MW-35) 

located directly downgradient of the Seam Master facility (Ref. 17, p. 15, 38, 61, 68, 310, 

311). Monitoring wells MW-34 and MW-35 are screened within the Gaspur Aquifer 

(Ref. 17, p. 38, 51; Ref. 21, p. Plate 3A and 6A; Ref. 32). This supports the evidence 

that the Bellflower Aquiclude and Semi-perched Aquifer are interconnected with the 

underlying formations (i.e., Lakewood Formation) since contaminants have passed 

through to the lower aquifers. 

• An examination of DWR Geologic Sections B-B’ and L-L’ indicates that the Gaspur 

Aquifer is in direct contact with the Exposition Aquifer in the property vicinity (Ref. 21, 

Plates 3A, 6A, and 6E; Ref. 32, p. 2; Figures A-1 and A-2 of the HRS documentation 

record). 

• An examination of DWR Geologic Section B-B’ indicates that the unnamed aquiclude 

between the Exposition and Gage Aquifers is not continuous within 2 miles of the Seam 

Master facility. This aquitard is shown as pinching out approximately 1,500 feet to the 

west of the property, resulting in a merging of the two aquifers [Ref. 1, Section 3.0.1.2.1; 

Ref. 21, Plates 3A and 6A (Geologic Section B-B’); Ref. 32, p. 2; Figures A-1 and A-2 of 

the HRS documentation record]. 

The Seam Master property is located in an urban area, in which numerous drinking water wells 

are located (Ref. 3; Ref. 14; Ref. 18; Ref. 19; Ref. 25; Ref. 32, p. 2; Figure A-1 of the HRS 

documentation record). Eight drinking water wells screened within the Gage and Exposition 

Aquifers are located within 4 miles of Source 1 (Ref. 13, p. 2; Ref. 18; Ref. 19; Ref. 21, Plate 

3A; Ref. 23; Ref. 25; Ref. 32, p. 2; Section 3.3.2.4 and Figure A-4 of the HRS documentation 

record). 

An observed release to the aquifer has been documented in ground water samples collected at the 

Seam Master Industries site. Hazardous substances that meet the criteria for an observed release 

by chemical analysis were detected in Source 1 (see Section 2.2.2 of this documentation record). 

Background samples used to evaluate an observed release by chemical analysis is located 

upgradient of the source at the Jervis B. Webb site. An observed release of TCE and cis-1,2-DCE 

is documented from the Seam Master property based on chemical analysis (see above tables in 

Section 3.1.1 of the HRS documentation record). 

The evidence provided in this section of the HRS documentation record for the Seam Master site 

documents that an observed release has occurred by chemical analysis of ground water samples 
September 2011 

31

to the Semi-Perched/Gaspur/Exposition/Gage interconnected aquifer of the hazardous substances 

listed below (Ref. 1, Sections 2.3 and 3.1.1). 

Hazardous Substances Released

TCE and cis-1,2-DCE 

Ground Water Observed Release Factor Value: 550
September 2011 

32

3.1.2 POTENTIAL TO RELEASE

Potential to Release was not scored, because an Observed Release was established. 
September 2011 

33

3.2 WASTE CHARACTERISTICS

3.2.1 TOXICITY/MOBILITY

Hazardous 

Substance

Source 

No.

Toxicity 

Factor 

Value 

(Ref. 1, 

Section 

3.2.1.1)

Mobility 

Factor 

Value*

Does 

Hazardous 

Substance 

Meet 

Observed 

Release? (Y/N)

Toxicity/ 

Mobility Factor 

Values (Ref. 1, 

Section 3.2.1.3, 

Table 3-9)

Reference

TCE 1 10,000 1 Y 10,000 Ref. 12, p. 1 

cis-1,2-DCE 1 100 1 Y 100 Ref. 2, p. 5 

* Hazardous substances meeting the criteria for an observed release by chemical analysis receive a mobility factor 

value of 1 (Ref. 1, Section 3.2.1.2). 

Toxicity/Mobility Factor Value: 10,000 

(Ref. 1, Section 3.2.1.3, Table 3-9) 

Notes: 

Y: Yes 

N: No 
September 2011 

34

3.2.2 HAZARDOUS WASTE QUANTITY

Source No. Source Type Source Hazardous Waste Quantity

1 Contaminated Soil >0 

sum: >0 

The hazardous waste quantity assigned from Section 2.4.2 of the HRS documentation record for 

Source 1 is unknown, but greater than 0. The hazardous waste quantity factor value assigned for 

the ground water pathway is 10 (Ref. 1, Sections 2.4.2.2 and 3.2.2, Table 2-6). 

Hazardous Waste Quantity Factor Value: 10

3.2.3 WASTE CHARACTERISTICS FACTOR CATEGORY VALUE

Toxicity/Mobility Factor Value: 10,000 

Hazardous Waste Quantity Factor Value: 10 

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

Waste Characteristics Factor Category Value (subject to a maximum of 100): 18

(Ref. 1, Sections 2.4.3.1 and 3.2.3, Table 2-7) 
September 2011 

35

3.3 TARGETS

The Seam Master Industries property is located in an urban area, in which numerous drinking 

water wells are located (Ref. 13; Ref. 18; Ref. 19; Ref. 25; Figures A-1 and A-4 of the HRS 

documentation record). Ground water contamination within the Gaspur aquifer has been 

identified beneath the Seam Master property (Ref. 4, p. 13, 14; Ref. 17, p. 43, 44, 51, 52; Ref. 

22, p. 70). Eight drinking water wells screened within the Gage and Exposition aquifers are 

located within 4 miles of the source at the site (Ref. 13, p. 2; Ref. 18; Ref. 19; Ref. 21, Plate 3A; 

Ref. 25; Ref. 23; Sections 3.3.2.4 and Figure A-4 of the HRS documentation record). These 

wells were evaluated for potential contamination. Interconnections between the Semi-perched, 

Gaspur, Exposition, and Gage aquifers is established within 2 miles of the source at the site and 

therefore are eligible to be scored as one interconnected aquifer (Ref. 1, Section 3.0.1.2.1; Ref. 

21, Plates 3A, 6A, and 6E; Section 3.0.1, Figures A-1 and A-2 of the HRS documentation 

record). 

3.3.1 NEAREST WELL

Well ID: City of South Gate Well 24. This well is located 0.32 mile northeast of Source 1 at the 

site (Ref. 13, p. 1, 2; Figure A-4 of the HRS documentation record). Examination of DWR Plate 

3A indicated that City of South Gate Well 24 is located nearest to transect line L-L’-L”, 

approximately 0.15 mile from Well A5 and 0.25 mile from Well B3 (Ref. 21, Plate 3A; Ref. 13; 

Ref. 32, p. 2). Examination of DWR geological section L-L’-L” indicates that the tip of the 

Gage Aquifer occurs at approximately 300 feet bgs and the bottom occurs at approximately 350 

feet bgs in the vicinity of Wells 3S/12W-6A5 and 3S/12W-6B3 (Ref. 21, Plate 6E). The first 

perforation for City of South Gate Well 24 occurs at 310 feet bgs (Ref. 13). City of South Gate 

Well 24 is screened in the Gage Aquifer. 

Level of Contamination (I, II, or potential): Potential. Sampling data are not available for this 

well so Level I or II actual contamination cannot be documented. 

Nearest Well Factor Value: 18 

(Ref. 1, Table 3-11) 

3.3.2 POPULATION

Within a 4-mile radius of the site source, there are at least eight drinking water wells that serve a 

total population of approximately 62,256 people. The wells located within the 4-mile radius 

encompass municipal drinking water wells (Ref. 1, Sections 3.0.1.1 and 3.3.2; Ref. 13; Ref. 18; 

Ref. 19; Ref. 25; Figure A-4 of the HRS documentation record). 
September 2011 

36

3.3.2.1 Level of Contamination

3.3.2.2 Level I Concentrations

Level I Concentrations are not assigned. 

Level I Concentrations Factor Value: 0

3.3.2.3 Level II Concentrations

Level II Concentrations are not assigned. 

Level II Concentrations Factor Value: 0 
September 2011 

37

3.3.2.4 Potential Contamination

Four municipalities that have public water systems located within 4 miles of the sources at the 

site were evaluated (Figure A-4 of the HRS documentation record; Ref. 1, Section 3.3.2). The 

four municipalities are the City of South Gate, Walnut Park Mutual Water Company, Maywood 

Mutual Water Company #3, and City of Lynwood. Each municipality’s water supply system is 

described below. 

City of South Gate

The City of South Gate operates a drinking water system that serves approximately 96,375 

people. Currently, the City of South Gate obtains all of its drinking water from ground water. 

The blended system consists of seven active drinking water wells (Wells 14, 19, 24, 25, 26, 27 

and 28), four stand-by wells (Wells 14, 19, 22B, 23), and most recently one destroyed (Well 7). 

No single well provides more than 40 percent of the total demand at any given time. Wells 14 

and 19 provide 30 percent of the demand, Wells 24 and 25 provide 20 percent of the demand, 

Well 26 provides 20 percent of the demand, Well 27 provides 10 percent of the demand, and 

Well 28 provides 20 percent of the demand. The City of South Gate does not sell or purchase 

water to other water systems and/or water users. In 2002, water quality sampling detected TCE 

in standby Well 7 at a concentration of 10.5 parts per million (Ref. 13). 

Examination of DWR Plate 3A indicated that City of South Gate Well 24 is located nearest to 

transect line L-L’-L”, approximately 0.15 mile from Well A5 and 0.25 mile from Well B3 (Ref. 

21, Plate 3A; Ref. 13; Ref. 32, p. 2). Examination of DWR geological section L-L’-L” indicates 

that the tip of the Gage Aquifer occurs at approximately 300 feet bgs and the bottom occurs at 

approximately 350 feet bgs in the vicinity of Wells 3S/12W-6A5 and 3S/12W-6B3 (Ref. 21, 

Plate 6E). The first perforation for City of South Gate Well 24 occurs at 310 feet bgs (Ref. 13). 

City of South Gate Well 24 is screened in the Gage Aquifer. 

Calculation: 96,375 people/7 wells = 13,767.85 people per well 

Walnut Park Mutual Water Company

The Walnut Park Mutual Water Company operates a drinking water system that serves 

approximately 17,000 people. The system consists of two active drinking water wells, Well 10 

and Well 11, and one standby well, Well 12. Currently, Well 12 is non-operational and not 

contributing any water to the system. Walnut Park Mutual Water Company does not sell or 

purchase water from any other water purveyors. All of the water distributed by Walnut Park 

Mutual Water Company is from ground water. Water from the two wells is blended evenly prior 

to distribution (Ref. 18). 

Examination of DWR Plate 3A indicated that Walnut Park Mutual Water Company Wells 10 and 

11 are located nearest to transect line K-K’-K”, approximately 0.25 mile from Wells P2 and B1 

(Ref. 3; Ref. 18; Ref. 21, Plate 3A; Ref. 32, p. 2; Figure A-1 of the HRS documentation record). 

Examination of DWR geologic section K-K’-K” indicates that the tip of the Exposition Aquifer 

occurs at approximately 150 feet bgs and the bottom occurs at approximately 250 feet bgs in the 

vicinity of Wells 2S/13W-22P2 and 2S/13W-27B11 (Ref. 21, Plate 6E). The first perforations 
September 2011 

38

for Walnut Park Mutual Water Company Wells 10 and 11 occur at 205 feet bgs and 203 feet bgs, 

respectively (Ref. 18). Wells 10 and 11 are screened in the Exposition aquifer. 

Calculation: 17,000 people/2 wells = 8,500 people per well 

Maywood Mutual Water Company #3

The Maywood Mutual Water Company #3 operates a drinking water supply system that contains 

three active drinking water wells (Prospect #1, District #4, and Warehouse #7) that serve 

approximately 9,500 people. The Maywood Mutual Water Company #3 obtains all of its 

drinking water from ground water. The Prospect #1 well contributes 22.7 percent to the system, 

the District #4 well contributes 34.9 percent to the system, and the Warehouse #7 well 

contributes 42.4 percent to the system. The Maywood Mutual Water Company #3 does not 

purchase or sell their water to any other water purveyors. All three wells are screened in the 

Exposition Aquifer (Ref. 19). 

Well Name Gallons Per 

Minute (gpm) 

Percentage of 

Supply Associated Population Reference 

Prospect #1 400 22.7 9,500 * 0.227 = 2,156.5 Ref. 19 

District #4 1,300 34.9 9,500 * 0.349 = 3,315.5 Ref. 19

Warehouse #7 1,000 42.4 9,500 * 0.424 = 4,028 Ref. 19

City of Lynwood

The City of Lynwood operates a drinking water supply system that contains five active drinking 

water wells (Wells 5, 8, 9, 11, and 19) that serve approximately 65,965 people. Currently, all of 

the water is obtained from ground water, however approximately one to two percent of the water 

distributed is purchased from the Municipal Water District, on an as needed basis. No one well 

supplies more than 40 percent to the entire system. Well 5 contributes 9.73 percent to the 

system, Well 8 contributes 19.47 percent to the system, Well 9 contributes 21.24 percent to the 

system, Well 11 contributes 14.16 percent to the system, and Well 19 contributes 35.4 percent to 

the system (Ref. 25). 

Examination of DWR Plate 3A indicated that City of Lynwood Well 8 is located nearest to 

transect line C-C’-C”, approximately 0.75 mile from Well Q1 (Ref. 21, Plate 3A; Ref. 25; Ref. 

32, p. 2). Examination of DWR geologic section C-C’-C” indicates that the tip of the Exposition 

Aquifer occurs at approximately 175 feet bgs and the bottom occurs at approximately 260 feet 

bgs in the vicinity of Well 3S/13W-12Q1 (Ref. 21, Plate 6B). Perforations for City of Lynwood 

Well 8 occur at 161 to 175 feet bgs, 207 to 216 feet bgs, and 241 to 247 feet bgs (Ref. 25). Well 

8 is screened in the Exposition Aquifer. 

Examination of DWR Plate 3A indicated that City of Lynwood Well 19 is located nearest to 

transect line K-K’-K”, approximately 1 mile from Well H1 and adjacent to the C-C’-C” transect 

line (Ref. 21, Plate 3A; Ref. 25; Ref. 32, p. 2). Examination of DWR geologic section K-K’-K” 

indicates that the tip of the Gage aquifer occurs at approximately 250 feet bgs and the bottom 

occurs at approximately 300 feet bgs in the vicinity of Well 3S/13W-15H1 (Ref. 21, Plate 6E). 
September 2011 

39

The City of Lynwood Well 19 is screened from 250 to 878 feet bgs (Ref. 25). Well 19 is 

screened in the Gage Aquifer. 

Calculation: 65,965 people/6= 10,994.16 people per well/water source 

Distance-Weighted Population Values 

Distance 

Category 

(miles)

Public and Private Wells 

(Figure A-4 of the HRS 

documentation record)

Population 

Served Reference

Distance-Weighted 

Population Value 

(Ref. 1, Section 

3.3.2.4, Table 3-12) 

0 to -1/4 Total 0 0 

> 1/4 to 1⁄2 Total 13,767.85 10,122 

City of South Gate Well 24 13,767.85 Ref. 13 

> 1⁄2 to 1 Total 0 0 

> 1 to 2 Total 10,994.16 2,939 

City of Lynwood Well 8 10,994.16 Ref. 25 

> 2 to 3 Total 9,500 678 

Maywood Mutual #3 Prospect #1 2,156.5 Ref. 19 

Maywood Mutual #3 District #4 3,315.5 Ref. 19

Maywood Mutual #3 Warehouse #7 4,028 Ref. 19

> 3 to 4 Total 27,994.16 1306 

Walnut Park Mutual Well 10 8,500 Ref. 18 

Walnut Park Mutual Well 11 8,500 Ref. 18 

City of Lynwood Well 19 10,994.16 Ref. 25 

TOTAL: 15,045 

Sum of Distance-Weighted Population Values: 15,045 

Sum of Distance-Weighted Population Values/10: 1,504.5 rounded to 1,504 

Potential Contamination Factor Value: 1,504

3.3.3 RESOURCES

There is no information indicating that ground water drawn from any target well within 4 miles 

of the source at the site is used for commercial food/forage crop irrigation, livestock watering, 

commercial food preparation, or commercial aquaculture. It is likely that there are municipal 

and/or community swimming pools within the target distance limit that may be utilizing ground 

water from the aquifers being evaluated. However, the evaluation of resources would not affect 

the final HRS score or the listing decision. 

Resources Factor Value: 0 
September 2011 

40

3.3.4 WELLHEAD PROTECTION AREA

The Wellhead Protection Area Factor Value was not evaluated for the Seam Master HRS 

documentation record since the evaluation would not affect the final HRS site score or the listing 

decision. 

Wellhead Protection Area Factor Value: 0
September 2011 

41

Attachment A 
Figure

0 0.5 A-1

Mile

Property Location Map

Seam Master Industries

5211 Southern Avenue

South Gate, California

ih

Property

Location

Base Map: South Gate Quadrangle

7.5 Minute Series (Topographical),

USGS 1981, National Geographic TOPO!
Former

Above Ground

Pallet Production Area Storage Tanks

Seam Master Industries

Production Warehouse

Southern Avenue

Adella

Avenue

Parking Lot

Former

Above Ground

Storage Tanks

Concrete Liners

for Former

Above Ground

Storage Tanks

Underground

Storage Tank

Drum Storage

Office

Base Map: USA Prime Imagery, Los Angeles, Aerials Express 2009.Facility Features from: Weston Solutions, Inc.,Preliminary Assessment/Site Inspection Report, Seam Master Industries,South Gate, California, May 8, 2003.
U+

U+

U+U+

+U

+U

+U

+U

&.

&.

L

Seam Master Industries

Production Warehouse

Southern Avenue

Adella

Avenue

G

r

o

u

n

d

w

a

t

e

r

F

o

l

w

D

i

r

e

c

t

o

i

n

CPT-20 Bkg

CPT-16 BkgMW-10 Bkg

MW-34MW-35

MW-14 Bkg

SM-1-GW Bkg

SM-6-GW

MW-34MW-35

Base Map: USA Prime Imagery, Los Angeles, Aerials Express 2009.CPT and Well Locations from: Innovative Technical Solutions, Inc.,Cooper Drum Company Superfund Site Remedial Design TechnicallMemorandum for Field Sampling Results, Addendum No. 4, February 26, 2010.Grab Groundwater Samples Locations from: Weston Solutions, Inc.,Preliminary Assessment/Site Inspection Report, Seam Master Industries,South Gate, California, May 8, 2003.
!5

&<

&<

&<&<

&< &<

&<

&<

Figure

A-4

Legend

&< Drinking Water Well

!5 Source Boundary

Facility Boundary

Well Search Radius

0.25 mile

0.5 mile

1 mile

2 miles

3 miles

4 miles

0

Mile

Walnut Park

Well 10

Well 11

Maywood Mutual #3

Warehouse #7

Maywood Mutual #3

District #4

Maywood Mutual #3

Prospect #1

City of South Gate

Well 24

Drinking Water Well Radius Map

Seam Master Industries

5211 Southern Avenue

South Gate, California

City of Lynwood

Well 8

City of Lynwood

Well 19

Base Map: World Street Map: 2009 ESRI, DeLorme, NAVTEQ, TomTom, USGS, Intermap,

AND, ESRI Japan, METI, ESRI Hong Kong, ESRI Thailand, Procalculo Prosis.

Well Locations from:

Hernandez, Ron, City of South Gate, Telephone Conversation recorded on Contact Report by Anitra B. Rice

and Amanda K.C. Reilly, Weston Solutions, Inc., January 4 and June 22, 2011. 

Gonzalez, Martin, Walnut Park Mutual Water Company, Telephone Conversation recorded on Contact Report by

Anitra B. Rice and Amanda K.C. Reilly, Weston Solutions, Inc., October 29, 2010 and June 30, 2011. 

Rohlf, Bob, Maywood Mutual Water Company #3, Telephone Conversation recorded on Contact Report by

Anitra B. Rice and Amanda K.C. Reilly, Weston Solutions, Inc., December 2, 2010 and August 24, 2011. 

Molina, Jose, City of Lynwood Public Works, Telephone Conversation recorded on Contact Report by

Karen Jurist, USEPA, May 25, 2011.

1