Vancouver Water Station #4 is a public drinking water wellfield inside Waterworks Park in Vancouver, Washington. It supplies drinking water to roughly 230,000 people in the region. The City of Vancouver operates production wells at the site and treats the pumped water before sending it to customers. EPA added the site to the National Priorities List (NPL), the federal roster of priority Superfund sites, in October 1992.
The contaminant of concern is tetrachloroethylene, also called PCE or perchloroethylene. PCE is a solvent that can harm the nervous system, liver, kidneys, and reproductive system, and may increase cancer risk. It was first detected in groundwater at the site in 1988, and levels climbed above EPA's drinking water limit of 5 parts per billion in 1991 and 1992. EPA confirmed PCE in the groundwater at the site's remedial operable unit. The source of the contamination was never confirmed by EPA, though the City of Vancouver pursued responsible parties through legal settlements.
The City responded by installing air stripping towers. Air stripping forces air through the water, causing PCE to evaporate out of the water. Testing confirmed the treatment system effectively removed PCE from the drinking water supply. EPA selected the formal cleanup remedy in a Record of Decision issued September 1, 1999. That remedy called for continued operation of the City's treatment system along with monitoring. Construction of the remedy was completed on September 8, 1999. EPA conducted five-year reviews in 2003, 2008, and 2013 to verify the cleanup stayed protective of human health and the environment.
By June 2017, EPA completed a Final Close Out Report confirming all cleanup actions were finished. PCE in untreated groundwater dropped below federal and state drinking water standards, and the treated drinking water supply contains undetectable levels of PCE. No waste remains at levels that would prevent unrestricted use or unlimited exposure, so no further five-year reviews are required. EPA deleted the site from the NPL on February 6, 2018. The City continues to operate the wells as part of its drinking water supply system, and all water must still meet Safe Drinking Water Act standards. Ongoing monitoring tracks contaminated groundwater to make sure it stays within the original area.
Community members can find key documents, including the Record of Decision, Final Close Out Report, and Third Five-Year Review, through EPA's Superfund database. Physical copies are available at the City of Vancouver Water Resources Education Center and the EPA Region 10 Superfund Record Center in Seattle. For questions, contact the EPA Remedial Project Manager or the Community Involvement Coordinator.
