Thyroid Toxin Taints Water Supplies for Millions in Calif. & Nationwide
OAKLAND, Calif., July 16, 2001 - Sources of drinking water for more than 7 million Californians and unknown millions of other Americans are contaminated with a chemical that disrupts child development and may cause thyroid cancer, but is unregulated by the state or federal government, according to an investigation by Environmental Working Group (EWG).
Today EWG released "Rocket Science: Perchlorate and the Toxic Legacy of the Cold War," available at www.ewg.org. Perchlorate, the explosive main ingredient of missile and rocket fuel, has been detected in 58 California public water systems and in water or soil in 17 other states.
Citing EWG's study, The Sacramento Bee reported in a front-page story July 14 that the U.S. Environmental Protection Agency estimates 20 million people in California, Arizona and Nevada have some level of perchlorate, often undetectable, in their drinking water supplies.
But only a fraction of the water supplies in California or elsewhere have been tested, and the EPA believes perchlorate contaminates water wherever rocket fuel or rockets were made or tested - 39 states in all. "Rocket Science" makes public for the first time maps and databases of all known and suspected perchlorate contamination nationwide.
"We know the water supplies of millions of Californians are contaminated with perchlorate at potentially harmful levels," said Bill Walker, EWG's California director. "But that's just the tip of the iceberg. There are hundreds of untested wells and water systems across the country, and many Americans may be consuming a toxin which is a health threat at very low doses, especially to infants and children."
Too much perchlorate can damage the thyroid gland, which controls growth, development and metabolism. Fetuses, infants and children with thyroid damage may suffer mental retardation, loss of hearing and speech, or deficits in motor skills. At higher levels of exposure, perchlorate is known to cause cancer.
Neither California nor the EPA has established any safety standards for perchlorate in drinking water. The EPA is scheduled to begin nationwide water sampling this year, but it will be years before there are enforceable state or federal drinking water standards.
But it's unlikely that those standards will protect the public, particularly children. EWG calculates that the EPA's latest proposed standard would leave formula-fed infants exposed to between 7.5 and 2,000 times the safe level of perchlorate in drinking water.
EWG's recommendations for a perchlorate standard that will protect children were reviewed by Dr. Thomas Zoeller of the University of Massachusetts, an external peer reviewer of the EPA's proposed perchlorate regulations. Zoeller told The Bee that EWG "makes a scientifically valid case." He agreed with EWG's main finding: The EPA's risk assessment does not consider the possibility that infants and fetuses may be more sensitive to reductions in thyroid hormones caused by perchlorate contamination.
"Small, subtle changes in thyroid hormone levels in pregnant woman can predispose their children to measureable and permanent reductions in IQ and to Attention Deficit Disorder," Zoeller said.
But concerted pressure to set a looser perchlorate standard is coming from a powerful alliance of chemical companies, aerospace contractors and the U.S. Air Force. In an unethical attempt to prove perchlorate is safe, the Air Force is co-sponsoring tests in which human subjects are paid to swallow daily doses of perchlorate much higher than the levels currently recommended by EPA or California.
"In the name of national security the military created a widespread public health threat. Now they're trying to block safety standards that would protect people from that threat," said Walker. "It's clearly not in the public interest for the Air Force to be lobbying against EPA's efforts to set safety standards."
If standards are kept lax, the defense contractors responsible for perchlorate contamination will save millions of dollars in cleanup costs. Some contractors have already cut deals with the Air Force that will stick taxpayers with almost 90 percent of the cleanup bill. With cleanup of heavily contaminated sites estimated to take more than 200 years, the cost to taxpayers may reach billions of dollars.