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Protecting Our Groundwater

DTSC protects groundwater with statewide cleanups of dry-cleaning solvent. California orders phase-out of PCE within 12 years

Total Wells Exceeding the MCL (5.0 Micrograms per Liter) for PCE (428 Wells) and MDL (0.5 Micrograms per Liter) (907 Wells) MCL - Maximum Contaminant Level |MDL - Method Detection LimitCalifornia’s dependence on water that lies beneath the ground is enormous. Nearly half our drinking water comes from below-ground aquifers. Many farms that produce the vegetables and fruits we eat every day rely on water pumped from below.

Yet this precious resource is under siege, in part from a chemical that many of us have indirectly used for years. Dry cleaning solvent, or perchloroethylene (PCE), has seeped through soil and into underground aquifers to contaminate our water.

“Dry cleaners exist in almost every shopping complex. PCE was, and is, the most common chemical used to clean clothes,” says Barbara Cook, the Department of Toxic Substances Control’s Acting Assistant Deputy Director for the Brownfields and Environmental Restoration Program. “This chemical has been found in our soil and groundwater and threatens our drinking water in places where communities rely on underlying groundwater. More importantly, the vapors for this chemical in the groundwater or soil can and have migrated up into the soil, and ultimately, into the indoor air of our homes and businesses.”

The Department of Toxic Substances Control (DTSC) investigates and oversees dozens of projects where PCE has leaked into groundwater. These cleanups affect every part of the state and cost millions of dollars and many years to clean up.

DTSC is doing much to oversee cleanup of this chemical in groundwater and soil at former dry cleaners in the Bay Area, Los Angeles and the Central Valley.

People once believed that underground water sources renewed themselves and were naturally protected from contamination. By the 1960s and 1970s they discovered this was not the case. PCE seeps into the groundwater through sewer pipes and moves through soil after being dumped. Once in the water, it is very hard to remove PCE. Aquifers can remain contaminated for thousands of years, and can contaminate other water.

DTSC’s cleanup program works with communities, local officials, water companies and those responsible for the contamination to identify PCE sources and limit its spread. The cleanup program removes PCE through “pump and treat” systems to protect one of our most vital resources: our underground drinking water supply.

California, recognizing the need for change, has ordered dry cleaners to phase out use of PCE by 2023. The California Cleaners Association says about 85 percent of the state’s approximately 6,000 small-business dry cleaners still use PCE as their primary cleaning solvent. But some cleaners now use safer alternatives because of PCE’s potential health risk to their workers and the damage PCE causes to the environment.

DTSC is encouraged that these businesses are making the change.

DTSC protects groundwater with statewide cleanups of dry-cleaning solvent. California orders phase-out of PCE within 12 years
04/21/2011 01:23:33 PM
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