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A joint remediation investigation and feasibility study by the U.S. Environmental Protection Agency (EPA) and the Orange County Water District will address an area of groundwater contamination in an area, known as the “North Basin” which is several miles long and over a mile wide.
The North Basin is located in a northern portion of Orange County and includes parts of Fullerton, Anaheim, and Placentia. The Orange County groundwater basin is a source for drinking water for the region, providing the majority of the water used in 22 cities. However, in spite of the investigation and study, all drinking water provided to the public meets federal and state drinking water standards per local water officials.
Contamination in the North Basin is presumed to be the result of industrial solvent spills and leaks from manufacturing, metals processing businesses and dry cleaning facilities over the last several decades. The remediation investigation will include the installation of 14 groundwater monitoring wells along with the sampling and data collection to determine the extent of contamination in the North Basin and provide EPA with information needed to develop an initial cleanup plan.
Historical industrial activity has contaminated the soil and groundwater with chemicals, including tetrachloroethene (PCE), trichloroethene (TCE), 1,1-dichloroethene (1,1-DCE), and 1,4-dioxane. Federal standards for drinking water for both TCE and PCE are 5 parts per billion. Initial investigation of the groundwater in the North Basin has detected PCE concentrations up to 3,300 parts per billion and TCE concentrations up to 23,000 parts per billion, and four contaminated drinking water wells have been shut down.
“The Orange County groundwater basin is a vital source of drinking water for the 2.4 million people it serves,” said Alexis Strauss, EPA’s Acting Regional Administrator for the Pacific Southwest. “Protecting this resource is critical for our long-term water sustainability.”
In spite of the assurances that the drinking water in the North Basin is safe, potential health issues may exist. Exposure to PCE can have health impacts including liver damage and increased risk of cancer. TCE has been linked to various health conditions, including impacts to the central nervous system, immune and endocrine systems, fetal heart development, kidney and liver cancer, and non-Hodgkin’s lymphoma. The extent and nature of potential health effects depends on many factors, including the contaminant levels and the length of exposure to the pollution.
The Orange County Water District will reimburse the EPA for overseeing the work, as per agreement between the two agencies. The district has volunteered to complete this study, under EPA oversight, so cleanup can begin as soon as possible.
Meanwhile, the EPA will be working to identify potentially responsible parties to carry out the cleanup work after the plan is finalized. In addition, the EPA is working with the Santa Ana Regional Water Quality Control Board and the California Department of Toxic Substances Control to clean up soil and groundwater at a number of facilities believed to have contributed to the regional contamination.
The North Basin remedial investigation and feasibility study are expected to take up to two years to complete and is estimated to cost up to $4 million.
