04/23/91

CONTACT: Stanford University News Service (650) 723-2558

SLAC reports PCBs in ditch, plans cleanup

STANFORD -- Stanford Linear Accelerator Center (SLAC) officials have notified five public agencies that traces of hazardous PCBs have been found in a ditch at the Center.

Matthew Allen, associate director of the center, said that SLAC and the Department of Energy, which operates the center under contract with Stanford University, are moving "expeditiously" to conduct additional sampling and to undertake remedial steps.

"A firm of environmental specialists is being hired to verify and characterize the extent of the contamination and to recommend options for remediation and decontamination of the soil in accordance with Environmental Protection Agency guidelines," Allen said.

PCBs - polychlorinated byphenyls - are hazardous materials that biodegrade very slowly. They were first found in soil samples taken last year, Allen said. Retesting in January confirmed roughly the same level of contaminants, and no migration of the chemicals along the ditch.

"We were negligent in not reporting the presence of PCBs earlier, but we simply failed to do so," Allen said. "We will now move as fast as we can to remedy the situation."

Allen said that the center has notified the Department of Energy, San Mateo County, the Environmental Protection Agency's National Response Center, the Fish and Game Department, the Regional Water Quality Control Board, the town of Portola Valley, the city of Menlo Park, the Ladera Neighborhood Association and the horse training center.

EPA regulations require some remedial action for traces above the level of 50 parts per million. Center health and safety employees have measured from 47 to 370 parts per million of the chemical in a ditch that crosses beneath the center's southern boundary, Allen said.

The ditch extends into a brush-filled, non-residential area of Stanford land leased to Portola Valley Thoroughbred Training Center. The contaminants extend about 300 feet into the property, but are not near any structures, he said. The center is continuing to conduct soil sampling and monitoring activities, Allen said.

The source of the PCBs is not known, Allen said, although the center does have electrical transformers, a common source of the chemical.

"In the mid-1970s, new federal regulations controlled the use of PCBs, so the contamination probably occurred before that time," Allen said. "There is no evidence of a present source of contamination."

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