By Benjamin Spillman
The Desert Sun
January 11th, 2005
Perchlorate, a chemical used in rocket fuel, has been detected in drinking water throughout the United States.
The Environmental Protection Agency has suggested limiting the acceptable level of perchlorate in drinking water to 1 part-per-billion. California health officials have proposed a 6 parts-per-billion health goal.
However, studies have suggested that humans can tolerate more than 100 parts per billion without adverse health impacts.
The maximum concentration level in the United States is 200 parts per billion in Duval County, Fla. The chemical was detected at 67 parts-per-billion in San Bernardino County.
It has been detected in at least two wells in the Coachella Valley. One well in Palm Springs had a concentration of 6 parts-per-billion. A well in La Quinta tested at 5.5 parts-per-billion. The La Quinta well has been shut down.
Source: Desert Water Agency/Coachella Valley Water District/State of California/National Academy of Sciences.
The tolerable level of rocket fuel in drinking water could be higher than health officials once thought, according to a new study.
A much-anticipated report by the National Academy of Sciences indicates that safe levels of the chemical perchlorate could be 20 times higher than the Environmental Protection Agency has suggested in the past.
The study released Monday is expected to influence state and federal regulators as they craft the first-ever federal standard for acceptable levels of perchlorate in the drinking water supply.
A statement with the report said researchers, "disagree with the EPA’s conclusion," about how much perchlorate people can tolerate without adverse health impacts.
A White House spokesman said the study suggests the EPA could revise upward the acceptable amount of perchlorate.
"I think the EPA will reconsider," said Bob Hopkins, spokesman for the Office of Science and Technology Policy.
But environmental and public interest groups were quick to criticize the research they said was unduly influenced by perchlorate producers and the military, two groups on the hook for dealing with the chemical.
Much of the debate over the chemical has centered over how much exposure it takes to impair thyroid function in humans, something that can be especially important to pregnant women and infants.
Local water districts have detected perchlorate in at least two Coachella Valley wells but at levels below what the new study concluded would be safe.
Dave Luker, general manager of Desert Water Agency in Palm Springs, said the study affirmed his confidence in imported Colorado River water, the suspected source of local perchlorate contamination.
"I think the Colorado River has gotten, in many ways, a bad rap," Luker said. "We are very fortunate that our exposure to perchlorate is as little as it is."
Wells near defense industry manufacturing sites in Inland southern California have reported much higher levels of the chemical.
Concerns about perchlorate in a well on the Torres Martinez Indian reservation have prompted tribal officials to provide bottled water to about 30 homes.
The new study relies heavily on California research into the affect of perchlorate on healthy adults.
It contradicts data the EPA used to create a preliminary suggestion that the chemical should be limited to 1 part per billion in drinking water.
"I’ve always been a little concerned about the low numbers being the goal," Luker said. "We’ve probably been at the low levels for some time and just not known it."
Luker said perchlorate has been detected at 6 parts per billion in one Palm Springs well.
But even detecting the chemical at amounts lower than 4 parts per billion is costly. Removing it could cost 10 times the amount of money or more than current water treatment, he said.
The site of a defunct perchlorate factory near Henderson, Nev., is responsible for sending hundreds of pounds of the chemical per day into nearby Lake Mead, according to the EPA. The reservoir feeds the lower Colorado River and provides drinking water to Los Angeles and San Diego, among other places.
Local water districts use river water to recharge the underground supply.
In recent years environmental groups have urged the government to set low limits on how much perchlorate should be allowed in drinking water.
They cite studies that show the chemical can impair thyroid functions and pose a threat, particularly to infants.
They also point out tests that show the chemical can concentrate in produce irrigated with contaminated water.
Gina Solomon, a physician and senior scientist for the Natural Resources Defense Council, criticized the new study for relying too heavily on data from a small sample of healthy adults exposed to the chemical.
"They basically failed statistics 101," she said of the researchers.
She added that water quality regulators need to include perchlorate exposure through food when converting the new research into a drinking water standard.