Superfund Record of Decision (EPA Region 2): Vega Alta Public Supply Wells, Puerto Rico (First Remedial Action), September 1987

摘要

The Vega Alta Public Supply Wells site is a public water supply well field located in the municipality of Vega Alta, Puerto Rico, approximately 32 km west of San Juan where ground water is the primary source of water. The well field consists of eight active wells. It currently supplies about 3.8 million gallons per day of water to Vega Alta and surrounding residential areas. The Puerto Rico Aqueduct and Sewer Authority (PRASA) is responsible for operation and maintenance of the public water supply system. The first indication of contamination was discovered in June 1983, when a survey of public water wells made by the U.S. Geological Survey detected 574 ug/1 of trichloroethylene (TCE) in the Ponderosa public supply well. Other VOCs were detected at lower concentrations in non-public wells in the well field system and ground water contamination was suspected. In June and August of 1983 Ponderosa and well GE 1 were shut down by PRASA because of contamination, respectively. This shut down caused a potential water supply shortage in Vega Alta. PRASA constructed well Bajura 3 to eliminate the shortage. In 1984 an air stripper was constructed at the Ponderosa well and operated until May 1985 when technical problems arose with the air stripper. Currently, ground water is contaminated with 1,1,1-trichloroethene, tetrachloroethene, 1,2-dichloroethene, 1,1-dichloroethene and other VOCs.