New Findings Spur EPA to Rethink Perchlorate Regulation

Perchlorate seems to be everywhere these days. It is in a lot of water supplies, in fruits and vegetables, in Chile's Atacama Desert, and even on Mars.

That is good and bad news for the Defense Department and military contractors battling accusations that they have polluted groundwater with perchlorate, a primary component of rocket fuel.

The debate over perchlorate began after EPA began noticing it in groundwater at certain California Superfund sites in the 1980s, said Kevin Mayer, the Superfund project manager at the EPA Region 9 office in San Francisco.

There were huge gaps then in what was known about the chemical's toxicology and detection.

But in 1997, scientists developed a way of detecting concentrations of the chemical at 4 parts per billion, a level far lower than levels detectable previously. Almost overnight, it seemed, perchlorate was turning up everywhere, including the Colorado River, which provides water for 20 million people.

"It was pretty clear by the middle of 1997 that Region 9 had a big issue on its hands, bigger than the Superfund program was set up to deal with on a site-by-site basis," Mayer said. "We needed some really good science."

Science was critical because DOD and other parties that were being accused of polluting water and soil with perchlorate were arguing that they were not responsible for contamination nor for the extremely expensive cleanups.

"A lot of people like to know whose perchlorate it is when they find perchlorate where it isn't supposed to be," said Andrew Jackson, an engineering professor and perchlorate researcher at Texas Tech University.

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