Pascoag Water District Fact Sheet
In September of 2001, the gasoline additive methyl tertiary-butyl ether (MTBE) was discovered in the public drinking water well PW-3A in Pascoag, RI. The source of the contamination was determined to be the property located at 24 North Main Street in Pascoag (North Main Street Mobil). The extent of the release was exacerbated as public well PW-3A drew contaminants approximately 1,500 feet in a northerly direction from the source across an area covering approximately 20 acres. Other contaminants of concern are all gasoline related constituents and include benzene, ethylbenzene, toluene, xylenes, naphthalene and various oxygenates.
On January 11, 2002, PW-3A was decommissioned and Pascoag's water distribution system was connected to the nearby Village of Harrisville's water supply to provide the residents of Pascoag with clean potable water.
Soon after the discovery of the contamination, the owner of North Main Street Mobil went bankrupt. RIDEM took over investigation and remediation of the release. From 2001 through 2006, a total of ninety one (91) groundwater monitoring wells were installed in the area to facilitate mapping the vertical and lateral extent of the contamination. Many aquifer tests were performed to determine the severity and extent of contamination.
From 2001 through 2014, RIDEM operated and maintained a number of groundwater remediation systems. Over 12.5 million gallons of groundwater have been pumped and treated through activated carbon filters. It is estimated that over 3,100 equivalent gallons of gasoline have been removed as a result of these remediation actions.
A summary of the remediation activities can be found in the July, 2013 Groundwater Remediation Project Summary Report by Beta Group. A digital copy of this report is available here.