HRS DOCUMENTATION RECORD--REVIEW COVER SHEET

Name of Site: Hormigas Ground Water Plume

CERCLIS ID No.: PRN000206359

Date Prepared: October 2010

Contact Persons

Site Investigations: Denise Zeno (212) 637-4319

U.S. Environmental Protection Agency

New York, NY

Documentation Record: Ildefonso Acosta (212) 637-4344 

U.S. Environmental Protection Agency

New York, NY

Pathways, Components, or Threats Not Scored

The surface water, soil exposure, and air pathways were not scored because the listing decision is not significantly

affected by those pathways. The site score is sufficient to list the site on the ground water pathway score.
This page has been left blank intentionally.
1 

HRS DOCUMENTATION RECORD

Name of Site: Hormigas Ground Water Plume

CERCLIS ID No.: PRN000206359 [Ref. 3, p. 1]

EPA Region: 2 Date Prepared: October 2010

Street Address of Site: * Carretera 785 Km 4.9 [Ref. 3, p. 1]

County, State, and ZIP Code: Caguas, Puerto Rico 00725 [Ref. 3, p. 1]

General Location in the State: interior, east-central Puerto Rico [Figure 1]

Topographic Map: Caguas, PR [Ref. 5, p. 1]

Latitude: * 18° 13' 14.16" (18.2206°) North Longitude: * 66° 06' 3.6" (66.1010°) West

[Figure 1; Ref. 4, pp. 1-2; 5, p. 1]

The site consists of a ground water plume with no identified source(s) of contamination [Figure 1; Ref. 3, p. 1]. The area 

of observed ground water contamination consists of the Eufracia well, a former public supply well that was closed after 

contaminants were detected, and the area around the well [Figure 1]. The reference point for the street address and site 

latitude/longitude coordinates is the Eufracia well [Figure 1; Ref. 1, p. 51595; 4, pp. 1-2]. The Eufracia well does not 

have a specific street address (i.e., no number), but it is accessible from Carretera (i.e., Route) 785 and is located 

approximately 1,000 feet west of the road; the street address listed here identifies the nearest kilometer marker to the well 

[Figure 1; Ref. 11, pp. 3, 14-15, 48].

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

general area the site is located. They represent one or more locations EPA considers to be part of the site based on the 

screening information EPA used to evaluate the site for NPL listing. EPA lists national priorities among the known 

“releases or threatened releases” of hazardous substances; thus, the focus is on the release, not precisely delineated 

boundaries. A site is defined as where a hazardous substance has been “deposited, stored, placed, or otherwise come to 

be located.” Generally, HRS scoring and the subsequent listing of a release merely represent the initial determination that 

a certain area may need to be addressed under CERCLA. Accordingly, EPA contemplates that the preliminary 

description of facility boundaries at the time of scoring will be refined as more information is developed as to where the 

contamination has come to be located.

 Scores

Ground Water Pathway 100.00

Surface Water Pathway Not Scored

Soil Exposure Pathway Not Scored

Air Pathway Not Scored

HRS SITE SCORE 50.00
2 

WORKSHEET FOR COMPUTING HRS SITE SCORE

Hormigas Ground Water Plume

S S2

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

(from Table 3-1, line 13)

2a. Surface Water Overland/Flood Migration Component Not Scored

(from Table 4-1, line 30)

2b. Ground Water to Surface Water Migration Component Not Scored

(from Table 4-25, line 28)

2c. Surface Water Migration Pathway Score (Ssw) Not Scored

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

3. Soil Exposure Pathway Score (Ss) Not Scored

(from Table 5-1, line 22)

4. Air Migration Pathway Score (Sa) Not Scored

(from Table 6-1, line 12)

5. Total of Sgw2 + Ssw2 + Ss

2 + Sa2 10,000

6. HRS Site Score Divide the value on line 5

 by 4 and take the square root 50.00
3 

GROUND WATER MIGRATION PATHWAY SCORESHEET

Hormigas Ground Water Plume

GROUND WATER MIGRATION PATHWAY

Factor Categories & Factors

MAXIMUM VALUE VALUE ASSIGNED

Likelihood of Release

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(2b+2c+2d)]

500 not scored

3. Likelihood of Release 550 550

Waste Characteristics

4. Toxicity/Mobility * 10,000

5. Hazardous Waste Quantity * 100

6. Waste Characteristics 100 32

Targets

7. Nearest Well 50 50

8. Population

8a. Level I Concentrations ** 32,930

8b. Level II Concentrations ** 0

8c. Potential Contamination ** not scored

8d. Population (lines 8a+8b+8c) ** 32,930

9. Resources 5 5

10. Wellhead Protection Area 20 20

11. Targets (lines 7+8d+9+10) ** 33,005

12. Aquifer Score (lines 3x6x11 divided by 82,500) 100 100

13. Ground Water Migration Pathway Score (Sgw) 100 100.00

* Maximum value applies to waste characteristics category.

** Maximum value not applicable.
4 

REFERENCES

Reference

Number Description of the Reference

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

Volume 55, No. 241, pp. 51532-51667. http://www.epa.gov/superfund/sites/npl/hrsres/index.htm#HRS 

Rule. December 14, 1990. [138 pages]

2. EPA. Superfund Chemical Data Matrix, SCDM Data Versions: 1/27/2004 and 6/23/2006, 

(Trichloroethylene update), Appendices B-I (Hazardous Substance Factor Values) and B-II (Hazardous 

Substance Benchmarks); excerpts downloaded on April 1, 2010. A complete copy of SCDM is available at 

http://www.epa.gov/superfund/sites/npl/hrsres/tools/scdm.htm. [10 pages]

3. EPA. Superfund Site Information, Hormigas Groundwater Plume, Caguas, Puerto Rico: Site Information

and Actions. Downloaded from http://cfpub.epa.gov/supercpad/cursites/csitinfo.cfm?id=0206359 on 

March 26, 2010. [2 pages] 

4. Morales, Julissa, Region 2 Site Assessment Team 2 (SAT 2). Project Note to Hormigas Groundwater 

Plume HRS Site File, Subject: Latitude and Longitude Determination. March 25, 2010. [2 pages]

5. U.S. Department of the Interior Geological Survey (USGS). Caguas Quadrangle, Puerto Rico, 7.5-Minute 

Series (Topographic). 1982. [1 page]

6. Gilliland, Gerry, Weston Solutions, Inc. Project Note to Hormigas Ground Water Plume site file, Subject: 

Water Quality Reports – Hormigas Water System. April 2, 2010. [32 pages]

7. EPA. Envirofacts Warehouse, Safe Drinking Water Information System (SDWIS), Query Results, Caguas, 

Puerto Rico. Downloaded from

http://oaspub.epa.gov/enviro/sdw_query_v2.get_list?wsys_name=&fac_search=fac_beginning&fac_county

=CAGUAS&pop_serv=500&pop_serv=3300&pop_serv=10000&pop_serv=100000&pop_serv=100001&s

ys_status=&pop_serv=&wsys_id=&fac_state=PR&last_fac_name=&page=1&query_results=&total_rows_

found= on March 29, 2010. [3 pages]

8. Gilliland, Gerry, Weston Solutions, Inc. Project Note to Hormigas Ground Water Plume site file, Subject: 

Existing PRASA Analytical Data – Pozo Eufracia. March 31, 2010. [15 pages]

9. EPA. Envirofacts Warehouse, SDWIS Violation Report, Hormigas I. Downloaded from 

http://oaspub.epa.gov/enviro/sdw_report_v2.first_table?pws_id=PR0005426&state=PR&source=Groundw

ater&population=5488&sys_num=0 on April 2, 2010. [3 pages]

10. Blanco, Emma M., Puerto Rico Aqueduct and Sewer Authority (PRASA). Letter to Javier O. Torres, 

Puerto Rico Department of Health (PRDOH), RE: Closing Hormigas System, PWSID PR0005426. 

February 17, 2009. [5 pages]

11. Weston Solutions, Inc. Field Logbook with Photo Documentation, Hormigas Site Discovery, 

20113.111.002.0123.00, DCN: SAT2.123.001. August-December 2009. [91 pages]

12. Morales, Julissa, Weston Solutions, Inc. Sampling Trip Report, Work Assignment No. 0123, Hormigas 

Site Discovery, Document Control No. SAT2.20113.123.876. September 11, 2009. [23 pages]
5 

REFERENCES (continued)

Reference

Number Description of the Reference

13. EPA Region 2 Laboratory. Approval Form/Project Checklist and Associated File Documents/VOC Data,

Project Number: 09090001, Project/Survey Name: Hormigas Site Discovery. September 14-18, 2009. 

[659 pages]

14. Weston Solutions, Inc. Field Logbook with Photo Documentation, 20405.012.013.0930.00, Hormigas 

Groundwater Plume HRS Sampling, DCN: 930-4E-AGGO. February-March 2010. [49 pages]

15. Morales, Julissa, Weston Solutions, Inc. Revised Sampling Trip Report, Work Assignment No. 

20405.012.013.0930.00, Hormigas HRS, Document Control No. 930-2A-AGMH. April 1, 2010. [31 

pages]

16. EPA Region 2 Hazardous Waste Support Section (HWSS)/Regional Sample Control Center (RSCC). 

Record of Communication (ROC) #1 and Data Transfer Log with attached Organic Data Package, Subject: 

CLP Data Package for Quality Assurance Review, Site: Hormigas Groundwater Plume, Case #: 39528, 

SDG #: B5QH0, B5QB9. March 4-18, 2010. [66 pages]

17. EPA Region 2 HWSS/RSCC. ROC #2 and Data Transfer Log with attached Organic Data Package, 

Subject: CLP Data Package for Quality Assurance Review, Site: Hormigas Groundwater Plume, Case #: 

39528, SDG #: B5QB1, B5QA3. March 5-18, 2010. [106 pages]

18. Munch, J.W., ed., EPA National Exposure Research Laboratory. Method 524.2, Measurement of 

Purgeable Organic Compounds in Water by Capillary Column Gas Chromatography/Mass Spectrometry, 

Revision 4.1. EPA Office of Research and Development. 1995. [48 pages]

19. EPA. SOM01.2 Volatile Target Compound List and Corresponding CRQLs. Downloaded from

http://www.epa.gov/superfund/programs/clp/som-vtarget.htm on April 6, 2010. [2 pages]

20. Veve, Thalia D. and Bruce E. Taggart (editors), USGS. Atlas of Ground-Water Resources in Puerto Rico 

and the U.S. Virgin Islands, Section 2.5.1: Aguas Buenas-Juncos Region by Juan C. Puig (pp. 106-112). 

Water Resources Investigations Report 94-4198. Prepared in cooperation with EPA. 1996. [20 pages]

21. Rodríguez, José M., USGS. Assessment of Ground-Water Withdrawals at Municipal Industrial Parks in 

Puerto Rico, 2000; excerpts. Scientific Investigation Report 2004-5029. Prepared in cooperation with 

Puerto Rico Industrial Development Company (PRIDCO). 2004. [18 pages]

22. Renken, Robert A. et al, USGS. Geology and Hydrogeology of the Caribbean Islands Aquifer System of 

the Commonwealth of Puerto Rico and the U.S. Virgin Islands. USGS Professional Paper 1419. 2002. 

Excerpt. [20 pages]

23. Gilliland, Gerry, Weston Solutions, Inc. Project Note to Hormigas Ground Water Plume site file, Subject: 

Wells in the Project Study Area – Hormigas Ground Water Plume. July 22, 2010. [5 pages]

24. Molina-Rivera, Wanda L., USGS. Estimated Water Use in Puerto Rico, 2000. Open-File Report 2005-

1201. Prepared in cooperation with PRASA, Puerto Rico Department of Natural and Environmental 

Resources (PRDNER), and Puerto Rico Environmental Quality Board (PREQB). 2005. [35 pages]

25. Puerto Rico Environmental Quality Board (PREQB). Final Wellhead Protection Program. April 1991. 

[158 pages]
6 

REFERENCES (continued)

Reference

Number Description of the Reference

26. EPA. Region 2 Water, Wellhead Protection Program. From http://www.epa.gov/region02/water/whp.htm. 

Web Page last updated on August 28, 2009; Accessed and printed on April 6, 2010. [1 page]

27. Agency for Toxic Substances & Disease Registry (ATSDR). ATSDR ToxFAQs, Tetrachloroethylene, 

CAS # 127-18-4. U.S. Department of Health and Human Services. September 1997. [2 pages]

28. ATSDR. ATSDR ToxFAQs, Trichloroethylene, CAS # 79-01-6. U.S. Department of Health and Human 

Services. July 2003. [2 pages]

29. ATSDR. ATSDR ToxFAQs, 1,2-Dichloroethene, CAS # 540-59-0, 156-59-2, and 156-60-5. U.S. 

Department of Health and Human Services. September 1997. [2 pages]

30. Interstate Technology & Regulatory Cooperation (ITRC) Work Group In Situ Bioremediation Work Team 

and Industrial Members of the Remediation Technologies Development Forum (RTDF). 

Technical/Regulatory Guidelines, Natural Attenuation of Chlorinated Solvents in Groundwater: Principles 

and Practices; appendices not included. September 1999. [32 pages]

31. Casta Velez, Alfredo, Puerto Rico Department of Health (PRDOH). Letter to Rafael L. Lama, PRASA, 

Re: Notice of Violation 004-06, Well Eufracia – Hormigas System (PR0005426), Violation for PCE; with 

attached translation by Weston Solutions, Inc. October 31, 2006. [5 pages]

32. EPA Region 2 Laboratory. SOP# DW-1, Revision# 2.1, Analysis of Volatile Organic Compounds in

Drinking Water by Purge and Trap GC/MS. February 13, 2009. [28 pages]

33. EPA Contract Laboratory Program (CLP). Modifications Updating SOM01.1 to SOM01.2; with attached 

excerpts from SOM01.1. April 11, 2007. [117 pages]

34. Morales, Julissa, Weston Solutions, Inc, Region 2 SAT 2. Pre-CERCLIS Screening Report, Hormigas Site 

Discovery, Caguas, Puerto Rico. Prepared for EPA. February 2010. [97 pages]

35. Albatross. Material Safety Data Sheet, Albatross Superkleen S.P.I.F. April 1, 2004. [6 pages]

36. Gomez-Gomez, Fernando et al, USGS. Surface-Water, Water-Quality, and Ground-Water Assessment of 

the Municipio of Caguas, Puerto Rico, 1997-99; excerpts. Water-Resources Investigations Report 00-

4280. Prepared in cooperation with the Municipio Autonomo de Caguas. 2001. [17 pages]

37. Environmental Data Resources, Inc. (EDR). The EDR Radius MapTM Report with GeoCheck®, Hormigas 

Site Discovery, State Road 785 Km 4.9 Interior, Caguas, PR 00703, Inquiry Number: 2600220.2s. 

September 28, 2009. [47 pages]
SS – Site Summary

7 

SITE SUMMARY

The Hormigas Ground Water Plume site (CERCLIS ID No. PRN000206359) consists of a ground water plume with no 

identified source(s) of contamination, located in the municipality of Caguas, Puerto Rico [Figure 1; Ref. 3, p. 1]. The 

geographic coordinates of the site are 18 ̊ 13' 14.16" north latitude and 66 ̊ 06' 03.60" west longitude, based on the 

location of former public supply well Eufracia [Figure 1; Ref. 4, pp. 1-2; 5, p. 1].

The former Hormigas public water system (PWSID 5426) consisted of two wells (Eufracia and Hormigas) and served a 

population of 5,488 people; according to the system’s operator, Puerto Rico Aqueduct and Sewer Authority (PRASA), 

there were no other wells or surface water intakes contributing to the Hormigas system [Ref. 6, pp. 1, 3-4, 9, 15, 22, 31; 

7, p. 2]. The results for a sample collected from the Eufracia well in August 2006 by PRASA indicated the presence of 

tetrachloroethylene (PCE) at a concentration of 29 micrograms per liter (μg/L; PRASA reported results in milligrams per 

liter [mg/L], which EPA has converted to μg/L for consistency with the EPA data) [Ref. 8, pp. 1, 4]. Puerto Rico 

Department of Health (PRDOH) responded to this analytical result by issuing PRASA a Notice of Violation (NOV) for 

noncompliance in October 2006, explaining that the annual average PCE concentration of 7 μg/L exceeded the Maximum 

Contaminant Level (MCL) of 5 μg/L [Ref. 31, pp. 1-5]. EPA’s Safe Drinking Water Information System (SDWIS) 

reported that the Hormigas water system had a health-based violation for PCE during the reporting period July-September

2006 and that NOVs were issued, as well as an Administrative Order in February 2008 [Ref. 9, p. 1]. PRASA closed the 

Hormigas water system and disconnected the Eufracia and Hormigas wells as of February 2009, but the pumps remain in 

place [Ref. 7, p. 2; 10, p. 1; 11, pp. 15, 48, 54-56; 12, pp. 3-4]. 

U.S. Environmental Protection Agency (EPA) collected two ground water samples from the Eufracia well in September

2009, and the results confirmed the presence of PCE, this time at concentrations of 260-280 μg/L [Ref. 11, p. 15; 12, pp. 

5, 9, 17; 13, pp. 16-18, 20-22]. Trichloroethylene (TCE) and cis-1,2-dichloroethylene (cis-1,2-DCE) were also detected 

in the samples, at concentrations of 59-60 μg/L and 49-50 μg/L, respectively [Ref. 13, pp. 16-18, 20-22]. The PCE and 

TCE concentrations detected in the Eufracia well significantly exceed the shared MCL of 5 μg/L [Ref. 2, pp. 7, 10]. 

Samples collected from background wells showed non-detects for PCE, TCE, and cis-1,2-DCE [Ref. 11, pp. 10-12, 16-

17; 12, pp. 5, 9, 11, 17; 13, pp. 5, 8-9, 12, 25, 28, 31-32].

In December 2009, EPA conducted a reconnaissance effort in the vicinity of the Hormigas and Eufracia wells as part of a 

Site Discovery Initiative to identify possible sources of contamination [Ref. 11, pp. 24-39, 60-91]. In February 2010, 

EPA collected soil samples from seven facilities identified as possible sources[Ref. 14, pp. 3-49; 15, pp. 3-27]. PCE was

detected at just one location (Narvaez Cleaners) [Ref. 15, pp. 3, 5, 16, 21; 16, pp. 17, 20]. PCE was not detected in soil 

samples collected at other possible source locations, including facilities that are located between the contaminated sample 

and the Eufracia well [Ref. 15-17, all pages]. In addition, the Narvaez facility is located closer to six community supply 

wells where PCE was not detected (400-3,000 feet) than it is to the Eufracia well (4,400 feet) [Figure 1; Ref. 11, pp. 10-

12, 16-17; 12, pp. 5, 9, 11, 17; 13, pp. 5, 8-9, 12, 25, 28, 31-32]. Two of the uncontaminated community supply wells are 

located north of the Narvaez facility, as is the Eufracia well [Figure 1]. It should be noted that the general direction of 

ground water flow from the site vicinity is east-northeast [Ref. 20, p. 19]. During the site discovery efforts, EPA did not 

observe or identify any possible source facilities located hydraulically upgradient (i.e., west-southwest) of the Eufracia 

well [Ref. 11, pp. 3-39; 34, pp. 5-6, 11-16, 21]. Based on these considerations, there is not sufficient evidence (i.e., data 

for intervening areas) to attribute the ground water contamination in the Eufracia well specifically to sources at the 

Narvaez facility or any of the other facilities investigated during EPA’s Site Discovery Initiative and sampling event; 

therefore, there is no identified source(s) of contamination.
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JR Auto Body Collision & Paint

Lat: 18.2034 / Long: -66.1075

Taller Gonzalez

Lat: 18.2142 / Long: -66.0998

Mariel T-Shirts

Lat: 18.2088 / Long: -66.1137

Narvaez Cleaners

Lat: 18.2085 / Long: -66.1005

Country Professional Dry Cleaners

Lat: 18.2036 / Long: -66.1074

San Lorenzo Bu

Lat: 18.2129 / Long: 

Villas De Or

HM2-GW01/HM2-GW

Lat: 18.2154 / Long: 

Pozo Hormigas

*Inaccessible, no sample taken

Lat: 18.2177 / Long: -66.1000

El Paraiso

HM-GW05

Lat: 18.2079 / Long: -66.1025

Villa Vigia

HM-GW0

Lat: 18.2083 / Long

La Sierra Pozo #2

HM-GW08

Lat: 18.2065 / Long: -66.1078

La Sierra Pozo #1

HM-GW07

Lat: 18.2050 / Long: -66.1084

La Sierra Pozo #3

HM-GW09

Lat: 18.2131 / Long: -66.1025

Pozo Eufracia

HM-GW01 / HM-GW02 (Dup)

Lat: 18.2206 / Long: -66.1010

CLIENT NAME: PROJECT:

TITLE: 

Hormigas Ground Water Plume 

Environmental Protection Agen

Hormigas Ground Water Plume 

Hormigas Ward

Caguas PR

Figure 1 - Site Location 

Puerto Rico "

Site Location

P:\SAT2\Hormigas_SDI\MXD\07755_HGPO_HRS_SiteLocationMap.mxd 

NOTE: 1. Sampling, well, and possible source locations were recorded electronically using Global Positioning System (GPS) technology in the field. SOURCE: 1. USGS. 7.5 Minute Series Topographic Quadrangles: CAGUAS, PR. 1982. 2. Weston Solutions, Inc., Region 2 Site Assessment Team 2. Site Logbook, DCN # SAT2.123.001. August - December, 2009. 3. Weston Solutions, Inc. Site Logbook, Hormigas Ground Water Plume HRS Sampling, DCN # 930-4E-AGGO. Feburary 2010. 
9 

SD-Characterization and Containment

Source No.: 1

SOURCE DESCRIPTION

2.2 SOURCE CHARACTERIZATION

Number of the source: 1 

Source Type of the source: Other

Name and description of the source: Hormigas Ground Water Plume 

Source 1 is considered a contaminated ground water plume of unknown volume without an identified source. PRASA’s 

former Hormigas public water system (PWSID 5426) consisted of two wells (Eufracia and Hormigas) and served a 

population of 5,488 people [Ref. 6, pp. 1, 3-4, 9, 15, 22, 31; 7, p. 2]. The results for a sample collected from the Eufracia 

well in August 2006 by PRASA indicated the presence of PCE at a concentration of 29 μg/L [Ref. 8, pp. 1, 4; 31, p. 1]. 

PRDOH responded to this analytical result by issuing PRASA an NOV for noncompliance in October 2006, explaining 

that the annual average PCE concentration of 7 μg/L exceeded the MCL of 5 μg/L [Ref. 31, pp. 1-5]. EPA’s SDWIS 

reported that the Hormigas water system had a health-based violation for PCE during the reporting period July-September

2006 and that NOVs were issued, as well as an Administrative Order in February 2008 [Ref. 9, p. 1]. PRASA closed the 

Hormigas water system and disconnected the Eufracia and Hormigas wells as of February 2009, but the pumps remain in 

place [Ref. 7, p. 2; 10, p. 1; 11, pp. 15, 48, 54-56; 12, pp. 3-4].

EPA collected two ground water samples from the Eufracia well in September 2009, and the results confirmed the 

presence of PCE, this time at concentrations of 260-280 μg/L [Ref. 11, p. 15; 12, pp. 5, 9, 17; 13, pp. 16-18, 20-22]. 

TCE and cis-1,2- DCE were also detected in the samples, at concentrations of 59-60 μg/L and 49-50 μg/L, respectively 

[Ref. 13, pp. 16-18, 20-22]. The PCE and TCE concentrations detected in the Eufracia well significantly exceed the 

shared MCL of 5 μg/L [Ref. 2, pp. 7, 10]. Samples collected from several background wells showed non-detects for 

PCE, TCE, and cis-1,2-DCE [Ref. 11, pp. 10-12, 16-17; 12, pp. 5, 9, 11, 17; 13, pp. 5, 8-9, 12, 25, 28, 31-32].

Location of the source, with reference to a map of the site:

The ground water plume is identified by contamination found in the former Eufracia public supply well. For the purpose 

of this report, this well represents a minimum of the plume extent. The well is located in interior, east-central Puerto 

Rico and is shown in Figure 1. 

Containment

Release to ground water:

Based on evidence of hazardous substance migration (contamination detected in ground water samples collected from the 

Eufracia well) and due to the fact that there is nothing to prevent the plume from migrating further, a containment factor 

of 10 is assigned [Ref. 1, p. 51596; 11, p. 15; 12, pp. 5, 9, 17; 13, pp. 16-18, 20-22]. 
10

SD- Hazardous Substances

Source No.: 1

2.4.1 Hazardous Substances

Ground water samples collected by PRASA in 2006 and by EPA in 2009 showed the presence of chlorinated solvents in 

the former Eufracia public supply well, as described below. Background sample locations and contaminant levels for

comparison to the contaminated samples are discussed in Section 3.1.1.

PRASA Sampling – Ground Water Sample: August 2006 

PRASA collected quarterly samples from the Eufracia well for compliance with safe drinking water regulations [Ref. 31, 

pp. 1-5]. The results for a sample collected from the Eufracia well in August 2006 by PRASA indicated PCE at a 

concentration of 29 μg/L, as presented in the table below (Note: PRASA reported its results and method detection limits 

[MDL] in mg/L, which EPA has converted to μg/L for consistency with the EPA data presented in this report) [Ref. 8, pp.

1, 4; 31, p. 1]. The PRASA sample was collected and analyzed according to EPA Method 524.2 [Ref. 8, pp. 3-4]. The 

applicable concentration range of Method 524.2 can be 0.02–200 μg/L or 0.02–20 μg/L [Ref. 18, p. 4]. The method 

requires a number of quality controls, including demonstrations of capability, accuracy, and precision; analysis of blanks 

and surrogates; and determinations of MDLs for each analyte [Ref. 18, pp. 16-19]. EPA defines MDL as the “lowest 

concentration of analyte that a method can detect reliably in either a sample or blank” [Ref. 1, p. 51586]. The PRASA 

analytical results include MDLs for all parameters, but do not establish sample quantitation limits (SQL; “quantity of a 

substance that can be reasonably quantified given the limits of detection for the methods of analysis and sample 

characteristics”) [Ref. 1, p. 51586; 8, pp. 3-4].

Hazardous Substance Sample Number Date Sampled Result (μg/L) MDL (μg/L) Reference

PCE 06 H 2548 8/14/2006 29 0.50 8, pp. 1, 4

EPA Sampling Event – Ground Water Samples: August 2009 

EPA collected ground water samples HM-GW01 and HM-GW02 from the Eufracia well and background ground water 

samples HM-GW04, HM-GW05, HM-GW06, HM-GW07, HM-GW08, and HM-GW09 from several nearby wells in 

August-September 2009 [Ref. 11, pp. 10-17; 12, pp. 5, 9, 11, 17]. The EPA Region 2 Laboratory analyzed the samples 

for Target Compound List (TCL) trace concentration VOCs according to its Standard Operating Procedure (SOP) # DW1, “Analysis of VOCs in Drinking Water by Purge & Trap GC/MS”, dated February 13, 2009 [Ref. 13, pp. 3, 54-58; 32, 

p. 1]. The SOP is based on EPA Method 524.2, as is the analytical method used by EPA’s Contract Laboratory Program 

(CLP) for trace concentration VOC analyses [Ref. 32, p. 3; 33, p. 68]. Although the analyses were not performed under 

the CLP, the EPA laboratory was able to achieve SQLs equal to the CLP Contract-Required Quantitation Limits (CRQL)

of 0.50 μg/L for PCE, TCE, and cis-1,2-DCE [Ref. 1, p. 51585-51586, 51589; 13, p. 3; 19, pp. 1-2]. The Eufracia well 

samples (HM-GW01 and HM-GW02) required a 50x dilution for quantitation of PCE and TCE, so the SQLs are adjusted 

accordingly to 25 μg/L (0.50 μg/L x 50) [Ref. 13, pp. 481-544; 32, p. 18]. Chain-of-custody was maintained for the 

samples throughout collection, shipping, and analysis [Ref. 13, pp. 39-58, 432-433].

PCE, TCE, and cis-1,2-DCE were detected in the Eufracia well samples at individual concentrations ranging from 49 

μg/L to 280 μg/L, but were not detected (ND) in the background samples, as presented in the table below [Ref. 12, p. 5; 

13, pp. 5, 8-9, 12, 16-18, 20-22, 25, 28, 31-32, 445-471, 481-571]. Additional information regarding background 

conditions is presented in Section 3.1.1.
11

SD- Hazardous Substances

Source No.: 1

Hazardous 

Substance

Sample Number Date 

Sampled

Result 

(μg/L)

SQL (μg/L) Reference

PCE HM-GW01 09/01/2009 280 25 12, p. 5; 13, pp. 17, 

504

HM-GW02 09/01/2009 260 25 12, p. 5; 13, pp. 21, 

536

Background samples* 08/31/2009–

09/01/2009

ND 0.50 12, p. 5; 13, pp. 5, 

9, 12, 25, 28, 32, 

445-471, 545-571

TCE HM-GW01 09/01/2009 60 25 12, p. 5; 13, pp. 17, 

504

HM-GW02 09/01/2009 59 25 12, p. 5; 13, pp. 21, 

536

Background samples* 08/31/2009–

09/01/2009

ND 0.50 12, p. 5; 13, pp. 5, 

9, 12, 25, 28, 32, 

445-471, 545-571

cis-1,2-DCE HM-GW01 09/01/2009 49 0.50 12, p. 5; 13, pp. 17, 

481, 483

HM-GW02 09/01/2009 50 0.50 12, p. 5; 13, pp. 21, 

512, 514

Background samples* 08/31/2009–

09/01/2009

ND 0.50 12, p. 5; 13, pp. 5, 

8, 12, 25, 28, 31, 

445-471, 545-571

*Background samples include HM-GW04, HM-GW05, HM-GW06, HM-GW07, HM-GW08, and HM-GW09 [Ref. 

11, pp. 10-17; 12, pp. 5, 9, 11, 17].
12

SD-Hazardous Waste Quantity

Source No.: 1

2.4.2 Hazardous Waste Quantity

2.4.2.1.1 Hazardous Constituent Quantity

The information available is not sufficient to evaluate Tier A source hazardous waste quantity; therefore, hazardous 

constituent quantity is not scored (NS) [Ref. 1, pp. 51590-51591].

Hazardous Constituent Quantity (C) Value: NS

2.4.2.1.2 Hazardous Wastestream Quantity

The information available is not sufficient to evaluate Tier B source hazardous waste quantity; therefore, hazardous 

wastestream quantity is not scored [Ref. 1, p. 51591].

Hazardous Wastestream Quantity (W) Value: NS

2.4.2.1.3 Volume

Because there is a well with samples showing contamination in the ground water but the volume of the contaminated area 

has not been determined, the volume of the ground water contamination is considered to be greater than 0 (>0) cubic 

yards but unknown [Figure 1; Ref. 13, pp. 16-18, 20-22]. The source type is ‘Other,’ so the volume value is divided by 

2.5 to obtain the assigned value, as shown below [Ref. 1, p. 51591, Section 2.4.2.1.3, Table 2-5].

Dimension of source (yd3): >0 yd3

Volume (V) Assigned Value: (>0)/2.5 = >0

2.4.2.1.4 Area

Tier D is not evaluated for source type “other” [Ref. 1, p. 51591, Table 2-5, Section 2.4.2.1.3].

Area of source (ft2

): N/A

Area (A) Assigned Value: 0

2.4.2.1.5 Source Hazardous Waste Quantity Value

The source hazardous waste quantity value for Source 1 is >0 for Tier C - Volume [Ref. 1, p. 51591].

Source Hazardous Waste Quantity Value: >0
13

SD-Summary

SITE SUMMARY OF SOURCE DESCRIPTIONS

Source Number Source Hazardous 

Waste Quantity 

Value

Containment

Ground Water Surface 

Water 

Air (Gas) Air 

(Particulate)

1 >0 10 NS NS NS

NS = Not Scored
14

GW-General

3.0 GROUND WATER MIGRATION PATHWAY

3.0.1 General Considerations

The site is located in an area underlain by volcanic and volcaniclastic basement rocks (i.e., bedrock) [Figure 1; 20, p. 16; 

22, pp. 11, 14]. The unit is considered to be a stratum of limited and local ground water resources in Caguas, but it 

functions as a local source of water through fractures, joints, faults and the weathered-bedrock mantle [Figure 1; Ref. 5, 

p. 1; 20, p. 16; 21, pp. 12-18; 22, p. 14]. The well records for the Hormigas supply well show that it is 400 feet deep, 

with an open-hole screened interval in bedrock from 250 to 400 feet below ground surface (bgs) and a principal fracture 

from 300 to 305 feet bgs [Ref. 23, pp. 1-2, 4-5]. The depth of the Eufracia well is 360 feet, and the depths of the nearby 

community supply wells range from 350 to 485 feet [Ref. 23, pp. 1-2]. The wells are all located in the same topographic 

and geologic setting as the Hormigas well (i.e., volcanic and volcaniclastic rocks within the mountainous, interior region 

of Puerto Rico) [Figure 1; Ref. 5, p. 1; 20, pp. 13-14, 16; 23, p. 1]. The wells are also located within a single 

hydrogeologic terrane (CaHT2) that extends throughout the western portion of Caguas [Ref. 23, p. 1; 36, pp. 10-12, 17]. 

The extent of this terrane beyond Caguas is unknown [Ref. 36, p. 17]. Based on these considerations, hydrogeologic 

terrane CaHT2 is evaluated as the aquifer under consideration, and only targets within the immediate site area are 

included for HRS scoring purposes [Ref. 1, p. 51595; 23, pp. 1-2; 36, pp. 10-12, 17]. The general direction of ground 

water flow in the site vicinity is east-northeast [Ref. 20, p. 19].

The blended water supply system consisting of the Eufracia and Hormigas wells served an estimated population of 5,488

people during its operation; according to PRASA, there were no other wells or surface water intakes contributing to the 

Hormigas system [Ref. 6, pp. 1, 3-4, 9, 15, 22, 31; 7, p. 2]. The capacities of the Eufracia and Hormigas wells are 150 

and 100 gallons per minute (gpm), respectively [Ref. 23, pp. 1-3]. Based on these capacities, the relative contribution of 

the Eufracia well to the total blended system was 60% (i.e., 150 gpm/250 gpm), and the population apportioned to the 

well is 3,293 people [Ref. 1, p. 51603; 23, pp. 1-3]. Ground water in Caguas is the primary resource used for commercial 

irrigation [Ref. 24, p. 17]. Wellhead Protection Areas were delineated for all potable water wells in Puerto Rico, so the 

plume lies within a designated Wellhead Protection Area [Ref. 25, pp. 29-45; 26, p. 1].

The volcanic bedrock is described below:

Stratum 1/Aquifer

Stratum/Aquifer Name: Hydrogeologic Terrane CaHT2

Description: The volcanic and volcaniclastic rocks that underlie the eastern half of Puerto Rico’s interior ground-water 

province are mostly Early and Late Cretaceous in age [Ref. 22, p. 14]. Puerto Rico’s volcanic rocks include lava, tuff, 

breccias, and tuffaceous breccias [Ref. 20, p. 13]. Primary porosity of the rocks of the Interior province was destroyed by 

processes of compaction, diagenesis, and tectonic movement [Ref. 22, p. 14]. Hydrogeologic terrane CaHT2 consists 

mainly of volcaniclastics, breccias, sandstone, siltstone with minor limestone lenses, and subordinate amounts of ash to 

lapilli tuff [Ref. 36, p. 11]. The slope of the unit is variable and the soil cover varies from less than two to about five feet 

[Ref. 36, p. 12]. Fracturing is not pervasive but is important locally, and well yields range mostly from 20-40 gpm [Ref. 

36, p. 12]. The average specific capacity in CaHT2 is 1 gpm per foot of drawdown, and depth to water ranges from 18-

60 feet bgs [Ref. 36, p. 12]. Reported well depths in CaHT2 range from 135-500 feet bgs [Ref. 23, p. 2; 36, p. 17].
15

GW-Observed Release

3.1 LIKELIHOOD OF RELEASE

3.1.1 Observed Release

Aquifer Being Evaluated: Hydrogeologic Terrane CaHT2

An observed release is documented for the Hormigas Ground Water Plume site. Chemical analyses for ground water 

samples collected from the Eufracia well in 2009 show the presence of chlorinated solvents [Ref. 11, pp. 14-15; 12, pp. 5, 

9, 17; 13, pp. 16-18, 20-22, 481-544].

Direct Observation

The aquifer is not evaluated for observed release by direct observation.

Chemical Analysis

EPA collected ground water samples HM-GW01 and HM-GW02 from the Eufracia well and background ground water 

samples HM-GW04, HM-GW05, HM-GW06, HM-GW07, HM-GW08, and HM-GW09 from several nearby wells in 

August-September 2009 [Ref. 11, pp. 10-17; 12, pp. 5, 9, 11, 17]. The EPA Region 2 Laboratory analyzed the samples 

for TCL trace concentration VOCs according to its SOP # DW-1, “Analysis of VOCs in Drinking Water by Purge & 

Trap GC/MS”, dated February 13, 2009 [Ref. 13, pp. 3, 54-58; 32, p. 1]. The SOP is based on EPA Method 524.2, as is 

the analytical method used by EPA’s CLP for trace concentration VOC analyses [Ref. 32, p. 3; 33, p. 68]. Although the 

analyses were not performed under the CLP, the EPA laboratory was able to achieve SQLs equal to the CLP CRQLs of 

0.50 μg/L for PCE, TCE, and cis-1,2-DCE [Ref. 1, p. 51585-51586, 51589; 13, p. 3; 19, pp. 1-2]. The Eufracia well 

samples (HM-GW01 and HM-GW02) required a 50x dilution for quantitation of PCE and TCE, so the SQLs are adjusted 

accordingly to 25 μg/L (0.50 μg/L x 50) [Ref. 13, pp. 481-544; 32, p. 18]. Chain-of-custody was maintained for the 

samples throughout collection, shipping, and analysis [Ref. 13, pp. 39-58, 432-433].

PCE, TCE, and cis-1,2-DCE were detected in the Eufracia well samples at individual concentrations ranging from 49 

μg/L to 280 μg/L, but were not detected (ND) in the background samples, as presented below [Ref. 12, p. 5; 13, pp. 5, 8-

9, 12, 16-18, 20-22, 25, 28, 31-32, 445-471, 481-571].

Notes on sample similarity and background conditions:

All background and contaminated samples documenting the observed release were collected from the aquifer under 

consideration [Figure 1; Ref. 23, pp. 1-2; 36, pp. 10-12, 17]. Samples from the La Sierra wells are evaluated as 

representative background samples because the hydrogeologic terrane, geologic setting, topographic setting, and 

elevation intervals are the same asthe Eufracia well [Figure 1; Ref. 23, pp. 1-2; 36, pp. 10-12, 17]. The background and 

release samples were collected on the same day using the same sampling personnel and procedures [Ref. 11, pp. 14-17; 

12, pp. 2-5, 17]. The samples all were shipped to and arrived at the laboratory together, and they were all analyzed 

within the same laboratory batch under identical, acceptable QA/QC conditions [Ref. 13, pp. 41, 52, 62-64, 481-571]. 

The compounds found in the Eufracia well are not naturally occurring, and the non-detect concentrations in all the 

community supply wells show that the compounds are not ubiquitous in the area [Ref. 11, pp. 10-12, 16-17; 12, pp. 5, 9, 

11, 17; 13, pp. 5, 8-9, 12, 25, 28, 31-32; 27, p. 1; 28, p. 1; 29, p. 1; 30, p. 16].

Background Concentrations

During the August-September sampling event, EPA collected ground water samples from the following community 

supply wells in the Hormigasstudy area: Villa Vigia, El Paraiso, Los Velazquez, La Sierra 1, La Sierra 2, and La Sierra 3 

[Ref. 11, pp. 10-12, 16-17; 12, pp. 5, 9, 11, 17;]. Chlorinated solvents were not detected in any of the community supply 

well samples [Ref. 13, pp. 5-6, 8-9, 11-13, 24-26, 28-29, 31-32]. The La Sierra wells samples are considered most apt 

for comparison because the samples were collected on the same day as the Eufracia well samples, and the wells have 

similar geologic and topographic settings, as well as overlapping elevation intervals [Figure 1; Ref. 5, p. 1; 12, pp. 5, 9, 

17; 23, pp. 1-2]. The La Sierra wells are located 2,800-6,200 feet south-southwest of the Eufracia well, in a hydraulically 
16

GW-Observed Release

sidegradient direction [Figure 1; Ref. 20, p. 17].

Background Concentrations (continued)

Well 

Location

Elevation

(ft AMSL)

Well Depth

(ft bgs)

Bottom Elev.

(ft AMSL)

Sample

Station ID

Sample

Date 

Reference(s)

La Sierra #1 1408 485 923 HM-GW07 09/01/2009 12, pp. 5, 17; 23, pp. 1-2

La Sierra #2 1456 400 1056 HM-GW08 09/01/2009 12, pp. 5, 17; 23, pp. 1-2

La Sierra #3 1465 485 980 HM-GW09 09/01/2009 12, pp. 5, 17; 23, pp. 1-2

ft AMSL = feet above mean sea level

ft bgs = feet below ground surface

Sample ID Hazardous Substance Conc. (μg/L) SQL (μg/L) Reference(s)

HM-GW07 cis-1,2-DCE ND 0.50 12, p. 17; 13, pp. 24-

PCE ND 0.50 26, 41, 545-553

TCE ND 0.50

HM-GW08 cis-1,2-DCE ND 0.50 12, p. 17; 13, pp. 28-

PCE ND 0.50 29, 41, 554-562

TCE ND 0.50

HM-GW09 cis-1,2-DCE ND 0.50 12, p. 17; 13, pp. 31-

PCE ND 0.50 32, 41, 563-571

TCE ND 0.50

Contaminated Samples

EPA collected two ground water samples from the Eufracia well in September 2009, and the results confirmed the 

presence of PCE, this time at concentrations of 260-280 μg/L [Ref. 11, p. 15; 12, pp. 5, 9, 17; 13, pp. 16-18, 20-22]. 

TCE and cis-1,2- DCE were also detected in the samples, at concentrations of 59-60 μg/L and 49-50 μg/L, respectively 

[Ref. 13, pp. 16-18, 20-22]. The PCE and TCE concentrations detected in the Eufracia well significantly exceed the 

shared MCL of 5 μg/L [Ref. 2, pp. 7, 10].

Well 

Location

Elevation

(ft AMSL)

Well Depth

(ft bgs)

Bottom Elev.

(ft AMSL)

Sample

Station ID

Sample

Date 

Reference(s)

Eufracia 1494 360 1134 HM-GW01 09/01/2009 12, pp. 5, 17; 23, pp. 1-2

HM-GW02 09/01/2009 12, pp. 5, 17; 23, pp. 1-2

Sample ID Hazardous Substance Conc. (μg/L) SQL (μg/L) Reference(s)

HM-GW01 cis-1,2-DCE 49 25 12, p. 17; 13, pp. 16-

PCE 280 25 18, 41, 481-511

TCE 60 25

HM-GW02 cis-1,2-DCE 50 25 12, p. 17; 13, p. 20-

PCE 260 25 22, 41, 512-544

TCE 59 25
17

GW-Observed Release

Attribution:

EPA has not yet identified a surface source of the ground water contaminants in the Eufracia well. The compounds found 

in the well are not naturally occurring, and non-detect concentrations in all the community supply wells show that the 

compounds are not ubiquitous in the area [Ref. 11, pp. 10-12, 16-17; 12, pp. 5, 9, 11, 17; 13, pp. 5, 8-9, 12, 25, 28, 31-

32; 27, p. 1; 28, p. 1; 29, p. 1; 30, p. 16]. PCE and TCE are man-made chlorinated solvents that are commonly used in 

commercial/industrial operations such as dry cleaning and metal degreasing, while cis-1,2-DCE is used to make solvents 

and is a common breakdown product of PCE and TCE [Ref. 27, p. 1; 28, p. 1; 29, p. 1; 30, p. 16]. 

EPA has attempted to identify the source(s) of observed ground water contamination. In August and December 2009, 

EPA conducted reconnaissance efforts in the vicinity of the Eufracia well as part of a Site Discovery Initiative to identify 

possible sources of ground water contamination [Ref. 11, pp. 3-8, 24-39, 42-46, 60-91]. EPA inspected 17 facilities in 

the area as possible sources of contamination [Ref. 11, pp. 3-8, 24-39]. EPA also performed an environmental database 

search, and conducted records searches and interviews to document site histories and regulatory status of possible source 

facilities [Ref. 11, pp. 3-9, 18-20, 24-39; 34, pp. 5-7, 11-16; 37, pp. 1-47]. As a result of the site discovery efforts, EPA 

identified direct evidence of PCE use at one facility (Mariel T-Shirts), PCE storage at another facility (Narvaez 

Cleaners), and PCE emissions at a third facility (former Country Professional Dry Cleaners) [Ref. 11, pp. 6, 24-26, 42-

43, 66, 74; 34, pp. 29, 41, 47; 35, p. 1]. EPA identified four other facilities as possible sources based on operational 

histories and observations made during facility inspections [Ref. 11, pp. 27-28, 31, 33-34, 37, 77-83, 88; 34, pp. 11-16]. 

The locations of the seven facilities identified by EPA as possible sources are shown in Figure 1.

In February 2010, EPA collected soil samples from the seven facilities identified as possible sources[Ref. 14, pp. 3-49; 

15, pp. 3-27; 34, p. 16]. PCE was detected at just one location (Narvaez Cleaners, as described below) [Ref. 15, pp. 3, 5, 

16, 21; 16, pp. 17, 20]. PCE was not detected in soil samples collected at other possible source locations, including 

facilities that are located between the contaminated sample and the Eufracia well [Ref. 15-17, all pages]. In addition, the 

Narvaez facility is located closer to six community supply wells where PCE was not detected (400-3,000 feet) than it is to 

the Eufracia well (4,400 feet) [Figure 1; Ref. 11, pp. 10-12, 16-17; 12, pp. 5, 9, 11, 17; 13, pp. 5, 8-9, 12, 25, 28, 31-32]. 

Two of the uncontaminated community supply wells are located north of the Narvaez facility, as is the Eufracia well 

[Figure 1].

It should be noted that the general direction of ground water flow from the site vicinity is east-northeast [Ref. 20, p. 19]. 

During the site discovery efforts, EPA did not observe or identify any possible source facilities located hydraulically 

upgradient (i.e., west-southwest) of the Eufracia well [Ref. 11, pp. 3-39; 34, pp. 5-6, 11-16, 21]. The environmental 

database search also did not identify any known possible source facilities within 1 mile of the site in that direction [Ref. 

37, pp. 11-12].

Based on the above considerations, there is not sufficient evidence (i.e., data for intervening areas) to attribute the ground 

water contamination in the Eufracia well specifically to sources at the Narvaez facility or any of the other facilities 

identified during EPA’s Site Discovery Initiative and sampling event; therefore, there is no identified source(s) of 

contamination.

The seven facilities sampled by EPA in February 2010 are described below: 

1. Taller Pototo

Taller Pototo is an auto body repair and painting shop that has been in operation since 2000 [Ref. 11, p. 30]. The 

owner/operator ceased commercial operations in approximately 2007 and has only worked on personal cars at this 

location since then [Ref. 11, p. 31]. Paint, paint thinner, and solvents are used in this process, including MX2 Binder 

Additive, GP 60 Lacquer Thinners, Metalux 2 2K MS Hardener Medium, MX2 VOC 4.2 Clear Light Speed; Metaluz 2 

HS 2K Grey filler Primer, MX2 VOC 2.1 Clear, and DTM Primer Activator Medium [Ref. 11, pp. 30-31, 79; 34, p. 66]. 

The filings from auto repairs are washed into a septic tank located beneath the floor of the garage [Ref. 11, p. 30; 34, p. 

66]. During the facility inspection, EPA observed good housekeeping and did not see any spills or discharges [Ref. 11, 

pp. 30-31; 34, p. 66]. The garage is located at the edge of a vegetated cliff, adjacent to the owner’s residence [Ref. 11, 
18

GW-Observed Release

pp. 30-31]. On February 25, 2010, EPA collected surface soil and subsurface soil samples for TCL VOC analysis 

through the EPA Contract Laboratory Program (CLP) at the Taller Pototo facility [Ref. 14, pp. 17-19, 21; 15, pp. 3, 7-8, 

19, 26-27]. PCE, TCE, and cis-1,2-DCE were not detected in the soil samples [Ref. 17, pp. 65-85, 101-103]. With the 

exception of methylene chloride and acetone at estimated concentrations in some samples, VOCs were not detected in 

soil samples collected at the facility [Ref. 17, pp. 65-85, 101-103].

2. Mariel T-Shirts

The Mariel T-Shirts screen printing shop has been operated out of a private home in a residential area since 1999 [Ref. 

11, pp. 25-26, 71; 34, p. 41]. T-shirts are printed using an Octopus printing machine [Ref. 11, pp. 26, 71]. The screens 

are cleaned with mineral spirits and Ulano No. 60 Screen Filler, which contains no hazardous constituents [Ref. 11, pp. 

26, 72; 34, p. 41]. Non-toxic paint is used for the T-shirts [Ref. 11, p. 26]. Superkleen stain remover, which contains 

10% to 30% PCE, is used on T-shirts [Ref. 11, pp. 26, 74; 34, p. 41; 35, p. 1]. The Superkleen is poured into a sprayer 

and sprayed directly onto the stain; water is not used in the stain-removal process [Ref. 11, pp. 26, 74]. A wash sink, 

where equipment is cleaned, discharges directly to the ground surface behind the building, and there is a septic system 

located on the property [Ref. 11, pp. 25-26, 73, 75]. On February 22, 2010, EPA collected surface soil and subsurface 

soil samples for TCL VOC analysis through the EPA CLP at the Mariel T-Shirts facility [Ref. 14, pp. 5-9; 15, pp. 3, 5-6, 

15, 22-23]. PCE, TCE, and cis-1,2-DCE were not detected in the soil samples [Ref. 16, pp. 28-51, 64-66]. With the 

exception of methylene chloride at estimated concentrations in some samples, VOCs were not detected in soil samples 

collected at the facility [Ref. 16, pp. 28-51, 64-66].

3. Narvaez Cleaners

Narvaez Cleaners is a retail/commercial dry cleaning business that has been operating at the current location since 

approximately 2004 [Ref. 11, p. 24; 34, p. 47]. Prior to Narvaez Cleaners, the building housed a pizzeria for fifteen years 

and it was a residential home prior to that [Ref. 11, pp. 25, 63]. The facility operator indicated that it is a drop-off 

location only and that the dry-cleaning operations are conducted at another facility in Caguas [Ref. 11, pp. 24-25; 34, p. 

47]. Hazardous waste transport documents indicate that waste PCE and TCE have been removed from both properties

[Ref. 34, p. 47]. EPA observed poor housekeeping in the rear of the Hormigas facility, including two empty drums and 

two full, partially-rusted drums of PCE [Ref. 11, pp. 25, 64, 66; 34, p. 47]. A dry cleaning machine located at the facility

was reportedly purchased in approximately 2006 but was never used [Ref. 11, pp. 25, 63]. Bottles of household 

detergents and fabric softeners were scattered on the ground surface outside the laundry room on the west side of the 

building [Ref. 11, p. 67; 34, p. 47]. A septic system located in the rear of the property receives wastewaters from both 

the laundry and the residence [Ref. 34, p. 47]. There were multiple broken dry cleaning and washing machines observed 

at the lower back portion of the site [Ref. 11, pp. 65, 67; 34, p. 47]. On February 22, 2010, EPA collected surface soil 

and subsurface soil samples for TCL VOC analysis through the EPA CLP at the Narvaez Cleaners facility [Ref. 14, pp. 3-

5; 15, pp. 3, 5, 16, 21]. PCE was detected at a concentration of 19 micrograms per kilogram (μg/kg) in one surface soil 

sample and at an estimated concentration in the associated subsurface sample, but it was not detected in other soil 

samples collected at the facility [Ref. 15, pp. 3, 5, 16, 21; 16, pp. 10-27]. TCE, cis-1,2-DCE, and other VOCs were not 

detected in any of the soil samples [Ref. 16, pp. 10-27].

4. San Lorenzo Busline

The San Lorenzo Busline facility has been operating since 1989 repairing buses and trucks [Ref. 11, p. 33; 34, p. 54]. 

During the facility inspection, EPA observed poor housekeeping practices, including oil stains in the garage area [Ref. 

11, pp. 33-34; 34, p. 54]. Rusted paint cans, lacquer thinner (ChemSpec), and 5-gallon buckets of diesel oil were 

observed inside and around the garage [Ref. 11, p. 33; 34, p. 54]. According to the operator, the facility does not 

currently use chlorinated solvents for degreasing [Ref. 11, p. 33; 34, p. 54]. On February 24, 2010, EPA collected 

surface soil and subsurface soil samples for TCL VOC analysis through the EPA CLP at the San Lorenzo Busline facility 

[Ref. 14, pp. 14-15; 15, pp. 3, 6-7, 17, 24-25]. PCE, TCE, and cis-1,2-DCE were not detected in the soil samples [Ref. 

17, pp. 38-64]. With the exception of methylene chloride and acetone at estimated concentrations in some samples, 

VOCs were not detected in soil samples collected at the facility [Ref. 17, pp. 38-64].
19

GW-Observed Release

5. Country Professional Dry Cleaners.

On August 24-25, 2009, WESTON observed the vacant storefront with a faded sign, Country Professional Dry Cleaners

[Ref. 11, pp. 6, 8, 42-43; 34, p. 29]. At that time, the site had been closed for approximately one year [Ref. 11, p. 6]. As 

of February 2010, the facility was still vacant [Ref. 14, p. 10]. A Multi-system query on EPA’s website using Country 

Dry Cleaners indicated the address PR 172 Km 6.6, Bo. Cañaboncito Caguas, PR 00725, with minor violations related to 

PCE under Air Facility System ID 7202500126 [Ref. 34, p. 29]. On February 25, 2010, EPA collected surface soil and 

subsurface soil samples for TCL VOC analysis through the EPA CLP at the Country Professional Dry Cleaners facility 

[Ref. 14, pp. 19-20; 15, pp.3, 7-8, 13, 26-27]. PCE, TCE, and cis-1,2-DCE were not detected in the soil samples [Ref. 

17, pp. 86-100, 104-106]. With the exception of methylene chloride at estimated concentrations in some samples, VOCs 

were not detected in soil samples collected at the facility [Ref. 17, pp. 86-100, 104-106].

6. JR Auto Body Collision & Paint

The JR Auto Body Collision & Paint facility is an auto body repair and paint shop that has been in operation since 

approximately 1989 [Ref. 11, p. 37]. During the facility inspection, EPA observed average housekeeping with no spills 

or discharges [Ref. 11, pp. 37, 88; 34, p. 35]. Chemicals currently used at the facility include metal glaze polyester 

finishing and blending putty, OMNI base paint, and Nason 481-16 acrylic lacquer thinner [Ref. 11, p. 37]. Wastewater is 

discharged to a septic tank behind the building [Ref. 11, p. 37; 34, p. 35]. On February 24, 2010, EPA collected one 

surface soil sample for TCL VOC analysis through the EPA CLP at the JR Auto Body Collision & Paint facility, and 

attempted unsuccessfully to collect additional surface and subsurface soil samples [Ref. 14, pp. 15-16; 15, pp. 3, 6, 14, 

24]. PCE, TCE, and cis-1,2-DCE were not detected in the soil sample [Ref. 17, pp. 35-37]. With the exception of 

methylene chloride at an estimated concentration, VOCs were not detected in the soil sample collected at the facility 

[Ref. 17, pp. 35-37].

7. Taller Gonzalez

The Taller Gonzalez facility has performed auto body repair and paint services since 1997, when the garage was 

constructed [Ref. 11, pp. 27-28; 34, p. 60]. EPA observed good housekeeping in the auto body repair and paint area and 

the remainder of the facility [Ref. 11, pp. 27-28]. The chemical products observed included a petroleum-based solvent, 

an alcohol-based paint thinner, ChemSpec paints, and Dupont ChromaSystemTM Basemaker paint [Ref. 11, pp. 27-28]. 

On February 24, 2010, EPA collected surface soil and subsurface soil samples for TCL VOC analysis through the EPA 

CLP at the Taller Gonzalez facility [Ref. 14, pp. 12-14; 15, pp. 3, 6, 18, 24]. PCE, TCE, and cis-1,2-DCE were not 

detected in the soil samples [Ref. 17, pp. 11-34]. With the exception of methylene chloride at estimated concentrations, 

VOCs were not detected in soil samples collected at the facility [Ref. 17, pp. 11-34].

Hazardous Substances Released:

Cis-1,2-Dichloroethylene (cis-1,2-DCE) CAS No. 000156-59-2 

Tetrachloroethylene (PCE) CAS No. 000127-18-4 

Trichloroethylene (TCE) CAS No. 000079-01-6 

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 Ground Water Observed Release Factor Value: 550
20

GW-Waste Characteristics

3.2 WASTE CHARACTERISTICS

3.2.1 Toxicity/Mobility

Hazardous Substance Source 

Numbers

Toxicity 

Factor Value

Mobility 

Factor Value

Toxicity/ 

Mobility

Reference

cis-1,2-Dichloroethylene 1, OR 100 1.0 100 2, p. 4

Tetrachloroethylene 1, OR 100 1.0 100 2, p. 5

Trichloroethylene 1, OR 10,000 1.0 10,000 2, p. 10

OR = Observed Release

3.2.2 Hazardous Waste Quantity

Source Number Source Hazardous Waste Quantity 

(HWQ) Value (Section 2.4.2.1.5)

Is source hazardous constituent 

quantity data complete? (yes/no)

1 >0 No

Sum of Values: 1 (rounded to 1 as specified in HRS Section 2.4.2.2)

The sum corresponds to a hazardous waste quantity factor value of 1 in Table 2-6 of the HRS [Ref. 1, p. 51591]. 

However, based on the fact that targets are subject to Level I concentrations (see Section 3.3.2.3), a hazardous waste 

quantity factor value of 100 is assigned if it is greater than the hazardous waste quantity value from Table 2-6 (i.e., 1) 

[Ref. 1, pp 51591-51592]. Therefore, a hazardous waste quantity factor value of 100 is assigned for the ground water 

pathway [Ref. 1, pp 51591-51592]. 

3.2.3 Waste Characteristics Factor Category Value

TCE corresponds to the toxicity/mobility factor value of 10,000, as shown previously (see Section 3.2.1).

Toxicity/Mobility Factor Value (10,000) x Hazardous

Waste Quantity Factor Value (100): 1 x 106

The product (1 x 106

) corresponds to a Waste Characteristics Factor Category Value of 32 in Table 2-7 of the HRS [Ref. 

1, p. 51592].

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Hazardous Waste Quantity Factor Value: 100

Waste Characteristics Factor Category Value: 32
21

GW-Targets

3.3 TARGETS

The Hormigas well water system served an estimated population of 5,488 people and withdrew all of its water from the 

Eufracia and Hormigas public supply wells; according to available information, there were no other wells or surface 

water intakes contributing to the Hormigas system [Ref. 6, pp. 1, 3-4, 9, 15, 22, 31; 7, p. 2]. The capacities of the 

Eufracia and Hormigas wells are 150 and 100 gallons per minute (gpm), respectively [Ref. 23, pp. 1-3]. Based on these 

capacities, the relative contribution of the Eufracia well to the total blended system was 60 % (i.e., 150 gpm/250 gpm), 

and the population apportioned to the well is 3,293 people [Ref. 1, p. 51603; 23, pp. 1-3]. In response to a health-based 

violation (average PCE concentration exceeding the MCL) in 2006, the State issued Notices of Violation in November 

2007 and an Administrative Order in February 2008 [Ref. 8, pp. 1, 4; 9, p. 1]. PRASA closed the Hormigas water system 

and disconnected the Eufracia and Hormigas wells as of February 2009, but the pumps remain in place [Ref. 7, p. 2; 10, 

p. 1; 11, pp. 15, 48, 54-56; 12, pp. 3-4]. The level of contamination in the Hormigas well is unknown, so only the 

apportioned population for the Eufracia well (based on the population served by the well at the time of closure) is 

considered, as presented below:

Well Distance from 

Source (mi.)*

Population Level I Conc. 

(Y/N)**

Level II Conc. 

(Y/N)**

Potential 

Contam. (Y/N)

Reference(s)

Eufracia 0.0 3,293 Y N N Fig. 1; Ref. 6, 

pp. 1, 3-4, 9, 15, 

22, 31; 7, p. 2; 

8, pp. 1-8; 23, 

pp. 1-3

* Distance is measured from the center of the area of observed ground water contamination [Figure 1].

** Maximum Contaminant Level/Maximum Contaminant Level Goal (MCL/MCLG), Reference Dose Screen 

Concentration (RfD), and Cancer Risk Screen Concentration (CRSC) were used as benchmarks to evaluate the level of 

contamination [Ref. 1, p. 51593]. Applicable benchmarks for the contaminants detected in the observed release, 

presented here in μg/L for consistency with reported data, are as follows:

Substance MCL/MCLG RfD CRSC Reference(s)

cis-1,2-DCE 70 360 --- 2, p. 6

PCE 5 360 1.6 2, p. 7

TCE 5 11 0.21 2, p. 10

Level I Concentrations

Well Sample Substance Conc. (μg/L) Benchmark (μg/L) Reference(s)

Eufracia HM-GW01 PCE 280 1.6 (CRSC)

5 (MCL)

2, p. 7; 13, p. 17

TCE 60 0.21 (CRSC)

5 (MCL)

11 (RfD)

2, p. 10; 13, p. 17

HM-GW02 PCE 260 1.6 (CRSC) 

5 (MCL)

2, p. 7; 13, p. 21

TCE 59 0.21 (CRSC) 

5 (MCL)

11 (RfD)

2, p. 10; 13, p. 21
22

GW-Nearest Well/Population

3.3.1 Nearest Well

As identified in Section 3.3, the former Eufracia drinking water well is subject to Level I concentrations. Therefore, a 

nearest well factor value of 50 is assigned [Ref. 1, pp. 51602-51603].

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Nearest Well Factor Value: 50

3.3.2 Population

3.3.2.2 Level I Concentrations

As identified in Section 3.3, the former Eufracia drinking water well is subject to Level I concentrations. The population 

assigned to the well is also explained in Section 3.3.

Level I Well Population Reference(s)

Eufracia* 3,293 6, pp. 1, 3-4, 9, 15, 22, 31; 7, p. 2; 8, pp. 1-

8; 23, pp. 1-3 

==================================================================================

Population Served by Level I Wells: 3,293 Level I Concentrations Factor Value: 32,930 

* PRASA disconnected the Eufracia well as of February 2009, but the pump remains in place [Ref. 7, p. 2; 10, p. 1; 11, 

pp. 15, 48, 54-56; 12, pp. 3-4]. 

3.3.2.3 Level II Concentrations

The people formerly served by the contaminated drinking water well (Eufracia) are already counted under the Level I 

concentrations factor. The Level II concentrations factor value is 0 because there are no other points of withdrawal 

subject to Level II concentrations [Ref. 1, p. 51603].

Level II Well Population Reference(s)

N/A N/A N/A

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Population Served by Level II Wells: 0 Level II Concentrations Factor Value: 0

3.3.2.4 Potential Contamination

Due to the fact that the maximum score of 100.00 for the ground water pathway is achieved, potential contamination was 

not evaluated.

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Potential Contamination Factor Value: 0
23

GW-Resources/Wellhead Protection Area

3.3.3 Resources

Available information indicates that ground water is the primary resource used for commercial irrigation in Caguas [Ref. 

24, p. 17]. Therefore, a resources factor value of 5 is assigned [Ref. 1, p. 51604].

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Resources Factor Value: 5

3.3.4 Wellhead Protection Area

The Wellhead Protection Program for Puerto Rico was developed in accordance with Section 1428 of the Safe Drinking 

Water Act and approved by EPA in 1991 [Ref. 25, pp. 3-4; 26, p. 1]. Every potable water well in Puerto Rico is within a 

wellhead protection area [Ref. 25, pp. 29-45]. Based on this information, observed ground water contamination 

associated with the site lies within a designated wellhead protection area (i.e., at the contaminated Eufracia public supply 

well), and a wellhead protection area factor value of 20 is assigned [Ref. 1, p. 51604].

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Wellhead Protection Area Factor Value: 20