Group Says Chemicals in Water Supply Exceed Limits

Calling for tougher regulations of pesticides, a public interest group says government data show the levels of some chemicals found in California drinking water sources exceed health guidelines.

“The detections are not an indication that people are at a serious health risk,” said Brad Heavner, author of a report on pesticides for the California Public Interest Research Group (CALPIRG). “But there are enough question marks that the state of California needs to be a lot more protective and cautious than it has been.”

Examining state and federal test results from the last decade, the organization said it found that pesticides have been detected in drinking water sources serving 16.5 million people in 46 of California’s 58 counties.

The report urges that a few pesticides now in use be phased out and that the state adopt stricter standards limiting the levels of pesticides permitted in water supplies.

The legal limits set by the state “are not stringent enough to adequately protect human health,” CALPIRG contended in a statement.

Some pesticides detected in drinking water are not subject to health standards. And 15 pesticides represent health risks at concentrations below the state’s legally permitted levels, according to the report, which cites more conservative--though not enforceable--guidelines from the federal Environmental Protection Agency and Cal/EPA.

Dave Spath, division chief for the Drinking Water Program in the state Department of Health Services, said Tuesday that many of the federal EPA guidelines are unrealistically low. As for the Cal/EPA goals, he said that would be good in an ideal situation, but that state law requires his department to take into account feasibility, cost and benefits when devising regulations.

“I believe our drinking water standards are safe,” Spath said, calling them the strictest in the nation.

The test results examined by CALPIRG are conducted at the water source and are not necessarily indicative of what is flowing through a homeowner’s tap. If a pesticide exceeds the state limit, water suppliers customarily dilute the water with additional supplies to lower the contaminant level, shut down the source or treat it.

Spath also noted that some of the data may have been taken from monitoring wells not used by the public.

Lowering pesticide levels through treatment is a difficult task. Of the 600 suppliers that have detected pesticides, CALPIRG says only 40 have effective systems to reduce the concentrations.

A spokeswoman for the state Department of Pesticide Regulation conceded some of the report’s points.

“I think where we could agree with CALPIRG is that the program to prevent ground-water contamination has not been preventive enough. . . . We realized that some time ago,” said Veda Federighi. “We were always playing catch-up.”

Her agency is trying to address that, she said, by developing regulations that would greatly expand the acreage on which certain pesticides are restricted.