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Public Water Supply Wells in Maunabo Proposed for Superfund Cleanup

Release Date: 04/18/2006
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(San Juan, PR) Four wells supplying the Maunabo Urbano public water system are part of a newly proposed Superfund site in Puerto Rico. Gound water samples collected by the system’s operator, the Puerto Rico Aqueduct and Sewer Authority (PRASA), show levels of chlorinated solvents in one or more of the wells since March 2002.

“So far, treatment at the wells has not been effective and we cannot allow contamination to continue to impact the local water supply,” said Regional Administrator Alan J. Steinberg. “By placing this site on the National Priorities List of the most contaminated waste sites, EPA will continue to make progress through the Superfund program and get this site cleaned up.”

The Maunabo Urbano Public Wells are located in the southeastern area of the island and serve a total population of approximately 14,000 people apportioned equally among the four public supply wells (i.e. 3,500 per well). The ground water from which the wells draw contains the industrial solvents tetrachloroethylene (PCE), trichloroethylene (TCE), and cis-1,2-dichloroethylene (DCE). It is not yet clear where the source of this contamination is and EPA is working to better identify its nature and extent.

The Maunabo Urbano public water system consists of four ground water wells: Maunabo-1, Maunabo-2 (Bordaleza), Maunabo-3 (Calzada), and Maunabo-4 (San Pedro). The Puerto Rico Department of Health ordered PRASA to close a well after the initial detection of contamination in March 2002 because the concentration of one of the solvents exceeded the federal Maximum Contaminant Level (MCL), the level established to be protective of people’s health. PRASA opted to treat the ground water with carbon filtration tanks at the wellhead rather than close the well in order to meet water supply needs. Since then, the detections of solvents in raw ground water samples from Maunabo-1 have exceeded health-based drinking water standards on numerous occasions. Samples taken after treatment, including tap water samples collected along the distribution system down-line from Maunabo-1, indicate that the treatment has not been effective and that contaminated drinking water is reaching the consumers in the system. As part of its cleanup, EPA will take steps to ensure that the 14,000 people receiving water from these wells get water that meets federal standards.

For more information about EPA's Superfund program, please visit: www.epa.gov/superfund.