Ontario trichloroethylene groundwater plume set for cleanup and abatement

The remediation of a trichloroethylene (TCE) groundwater plume in Ontario (California), that has affected the groundwater supplies of area residents, is now set for cleanup and abatement following the adoption of a settlement agreement by the Santa Ana Regional Water Quality Control Board.

The cleanup order was issued to the cities of Ontario and Upland as well as six other entities after working under the Santa Ana Water Board’s oversight.  In addition to the two cities, Inland Empire Utilities Agency (IEUA), Aerojet Rocketdyne Inc., The Boeing company, General Electric Company, Lockheed Martin and the United States Department of Defense worked to reach an agreement to address the TCE plume.  They will also continue to provide replacement drinking water to residents with private wells that have been impacted.

Per the cleanup order, the cities of Ontario and Upland will assume responsibility for providing affected residents with an alternate water supply.  The TCE plume is located west of Interstate 15 and south of State Route 60 (Pomona Freeway) in Ontario; IEUA is responsible for cleanup of the plume. The companies, working jointly at ABGL, LLC, had earlier completed the TCE plume investigation; they had also voluntarily commenced the replacement water supply program for impacted residents. The cleanup also includes a collaborative endeavor between the Chino Basin Desalter Authority (CDA) and the public parties to leverage CDA’s planned expansion project.

TCE is a halocarbon – a volatile organic compound — and was widely used as an industrial degreasing and cleaning solvent beginning in the mid-1940s. It is a clear non-flammable liquid with a sweet smell. Groundwater contamination by TCE has become an important environmental concern for human exposure.

TCE use declined in the 1970s after environmental and economic concerns surfaced regarding its use. The US Environmental Protection Agency announced in 2005 they had completed a Final Health Assessment for Trichloroethylene and released a list of new TCE toxicity values. The results of the study have formally characterized the chemical as a human carcinogen and a non-carcinogenic health hazard. A 2011 EPA toxicological review continues to list trichloroethylene as a known carcinogen.

The two cities and the public partners will continue working under the Santa Ana Water Board as well as the delivery of drinking water supplies in the affected area.