Superfund Information Systems: Site Profile

Superfund Site:

SAN GERMAN GROUND WATER CONTAMINATION
SAN GERMAN, PR

Cleanup Activities

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Background

The San German Well Field Contamination site is located in the municipality of San German, southwest of Puerto Rico. The site consists of a groundwater plume with no identified source of contamination. The main contaminants of concern are tetrachloroethylene (PCE) and trichloroethylene (TCE), which are solvents used in degreasing, industrial cleaning and dry cleaning.

VOCs were detected above federal drinking water standards, called Maximum Contaminant Levels (MCLs), in three public water supply wells, identified as Retiro, Lola Rodriguez de Tio I (Lola I), and Lola Rodriguez de Tio II (Lola II).  These wells are all located south of the Guanajibo River, between Routes 139 and 360.  These wells were associated with the Puerto Rico Aqueduct and Sewer Authority (PRASA) San German Urbano Water system, which includes a total of seven wells and two surface water intakes.

PRASA closed the Retiro well on January 19, 2006.  The Lola I and Lola II wells were taken out of service in about the same time period because of exceedances in levels in those wells, too.

The Retiro, Lola I, and Lola II wells acted as an independent interconnected supply system with approximately 800 service connections serving approximately 2,280 users as of 2005.  The Site includes the Retiro Industrial Park, located approximately one‐half mile to the southeast of the affected supply wells.  The Industrial Park has been shown to be the source of the VOCs.  Several of the buildings in the industrial park are occupied by active businesses that were investigated during the RI.

 

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What Has Been Done to Clean Up the Site?

PRASA closed the Retiro well on January 19, 2006.  The Lola I and Lola II wells were taken out of service in about the same time period because of exceedances in levels in those wells, too. . On December 2015 EPA issued the OU-1 ROD to address contaminated soils and shallow, highly contaminated groundwater that acts as ongoing sources of groundwater contamination.

After investigations, EPA placed the site on the Superfund program’s National Priorities List in March 2008. On December 2015 EPA issued a ROD  addressing the soil and portion of the groundwater contamination detected at the Site.  After investigations, EPA placed the site on the Superfund program’s National Priorities List in March 2008.

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What Is the Current Site Status?

 

EPA is addressing the cleanup of this Site in two phases, OU-1 and OU-2.  On December 2015 EPA signed the OU-1 ROD. This is the first planned of two remedial action for the Site, addressing contaminated soils and shallow, highly contaminated groundwater that acts as ongoing sources of groundwater contamination.  The OU-1 source areas also act as a source of vapors that can enter into buildings in the vicinity of the Retiro Industrial Park.  By addressing the source areas first, EPA expects to begin to reduce the mass of contamination in the ground, thereby accelerating the overall groundwater cleanup.  further investigations of the diffuse groundwater plume (OU-2) are still needed and is currently ongoing before a remedy for that part of the Site can be selected.  By selecting and implementing the OU-1 remedy, EPA will be able to begin to address the Site contamination while completing the latter, OU-2 studies.

 

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Sampling and Monitoring

 

The nature and extent of contamination in Site media was assessed during the RI by collecting and analyzing samples and then comparing analytical results to federal, Commonwealth, and Site-specific screening criteria.  Five chemicals were identified as Site-related contaminants: PCE, TCE, cis-1,2-DCE, 1,1-dichloroethene (1,1-DCE) and vinyl chloride.  These five VOCs were detected the most frequently, and at the highest levels, in source area soil samples and other affected media including groundwater, surface water, and sediment.  These chemicals include chlorinated solvents and degradation products of those solvents.  The RI also investigated the Site for the presence of Site contaminants in the form of nonaqueous phase liquids.  Because Site contaminants are chlorinated VOCs that are denser than water, they are also referred to as dense, nonaqueous phase liquids (DNAPLs).

As part of the RI, soil, groundwater, surface water, sediment, and/or soil vapor were sampled at numerous locations at the Site.  Sampling was conducted at four facilities within the Retiro Industrial Park (Wallace, Pitusa, Former Baytex, and CCL) and a fifth facility, Acorn Dry Cleaner, located to the west of the Industrial Park.  In addition, soil vapor samples were collected in some residences within the area.  

Two rounds of sub-slab soil vapor sampling were performed.

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