Toxic Chemical Shuts 18 Water Wells in State

A hazardous chemical long used in the production of solid rocket fuel is being detected for the first time in drinking water, at high enough levels to cause 18 municipal wells to be shut down in Los Angeles, San Bernardino and Sacramento counties.

The chemical, perchlorate, has not previously been found in drinking water anywhere in the country, according to officials of the U.S. Environmental Protection Agency.

At very high levels, perchlorate interferes with the function of the thyroid gland and the production of hormones necessary for normal human development. In the worst cases, it can cause brain damage in fetuses and a potentially fatal form of anemia in adults.

Scientists say the levels being detected are well below those known to cause serious problems, but they are worried about the potential effects of lower doses--and acknowledge that they have inadequate information about that danger.

“There is a data gap between known effects of very high levels and possible effects at the levels being detected,” said Gina Solomon, a scientist with the Natural Resources Defense Council, an environmental group, and a member of an EPA advisory committee.

The California Department of Health Services recently advised that water systems take remedial action if perchlorate levels are found to exceed 18 parts per billion, considered the safe level. In response, officials shut down wells in Santa Clarita, the San Gabriel Valley, San Bernardino and the Sacramento area, according to state and federal officials.

Taking wells out of service is unusual, a state health official said, noting that of “a couple of thousand” wells from San Luis Obispo to San Diego, only 15 to 20 have been closed because of pollution this year--12 of those as a result of perchlorate.

Meanwhile, the Metropolitan Water District has found the chemical--in amounts less than 18 parts per billion--in the Colorado River, which supplies water to millions of people in the Southwest and Mexico.

In that river, “it is not currently a health concern,” said MWD chief of operations Jay Malinowski, “but any time you find something in water you haven’t seen before, you want to know why it is there and how to get rid of it.”

All of the discoveries have been made this year since state health department scientists developed a new technique for detecting comparatively low levels of perchlorate.

“Until this year, we were not able to detect it below several hundred parts per billion,” said Don Stralka, an EPA toxicologist. “Thanks to the state’s new methodology, we can find it as low as four parts per billion.”

State officials are now looking for perchlorate in drinking water sources near industrial operations, including manufacturers of munitions and fireworks, which frequently use the chemical.

The first discovery in drinking water was in municipal wells in Rancho Cordova in Sacramento County, near the Aerojet General Corp. federal Superfund site. That well along with six others in the vicinity have been taken out of service because of the contamination, said Alex Macdonald, a senior engineer with the state’s Central Valley Water Quality Control Board.

A chemical manufacturing and rocket testing company, Aerojet has been using and disposing of perchlorate since the early 1950s, Macdonald said. Since the early 1980s, Aerojet has been engaged in an EPA-supervised $100-million cleanup of polluted ground water. The cleanup, however, focused on removing other chemicals, not perchlorate.

State and federal officials said they have been aware for several years that perchlorate was in some ground water at very high levels--8,000 to 10,000 parts per billion--near the Aerojet site. But it didn’t become a matter of concern, they said, until the chemical was discovered this year in drinking water wells, at up to 280 parts per billion.

Subsequently, the chemical was found at other Superfund sites in Pasadena and elsewhere in the San Gabriel Valley, where cleanup efforts directed at other pollutants had failed to remove the perchlorate.

In all, health officials have tested 232 wells statewide and detected perchlorate in 69, with 24 of those registering concentrations above the “action level” (18 parts per billion), according to David Spath, chief of environmental management of the drinking water division of the state health department. The state has close to 6,000 sources of drinking water, including wells, lakes, rivers and reservoirs.

In some cases, officials said, they have avoided closing wells by blending the polluted water with purer water from other sources.

But officials say they are frustrated by their inability to find a reliable method of removing the chemical from water.

“It doesn’t seem to respond to any of the methods devised so far for removing industrial pollutants from water sources,” said Spath.

Though rocket fuel uses are believed to be the source of the current contamination, perchlorate once was widely used in medicine. It was prescribed for the treatment of certain thyroid disorders--until its toxic effects were understood.

Perchlorate is still used in Europe to treat thyroid conditions.