SEPA
United States
Environmental Protection
Agency
National Priorities List (NPL)
* * *Proposed Site * * *
HORMIGAS GROUND WATER PLUME
OSWER/OSRTI
Washington, DC 20460
October 2010
Caguas, Puerto Rico
(?) Site Location:
The Hormigas Ground Water Plume site, which consists of a ground water plume with no identified source(s) of
contamination, is located in the municipality of Caguas, in interior east-central Puerto Rico.
xl Site History:	
The former Hormigas public water system (PWSID 5426) consisted of two wells (Eufracia and Hormigas) and served a
population of 5,488 people. In August 2006, the system's operator, Puerto Rico Aqueduct and Sewer Authority (PRASA),
detected tetrachloroethene (PCE) above EPA's Safe Drinking Water Act Maximum Contaminant Levels (MCLs) in the
Eufracia well. In response, the Commonwealth issued Notices of Violation in November 2007 and an Administrative
Order in February 2008. PRASA closed the Hormigas water system and disconnected the wells in February 2009. EPA
collected two ground water samples from the Eufracia well in August 2009, and the results confirmed the presence of PCE.
Trichloroethene (TCE) and cis-l,2-dichloroethene (cis-l,2-DCE) were also detected in the Eufracia well.
I Site Contamination/Contaminants:
Chlorinated solvents (i.e., PCE, TCE, and cis-l,2-DCE) are present in ground water. The PCE and TCE concentrations
significantly exceed the MCLs.
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