In an alarming, newly published study, the U.S. Centers for Disease Control and Prevention says that even low-level exposure to perchlorate can interfere with normal thyroid function in women, specifically by reducing the production of essential thyroid hormones. Women with low levels of iodine in their urine have shown to be most susceptible to thyroid aliments. While the risks associated with high levels of perchlorate exposure have been long established, the new report has found lower levels of exposure to be more dangerous than previously thought.

The CDC survey was conducted on approximately 2,300 subjects–both male and female–in 2001 and 2002. The delayed release of the survey’s findings has caused considerable consternation among health officials and environmentalists. Some have accused the Bush Administration of pressuring the CDC to withhold the information from the public in order to protect the Pentagon and its contractors from increased regulation.

“The Pentagon and defense contractors, who are responsible for much of the perchlorate in drinking water supplies, have lobbied hard against federal standards, arguing that perchlorate posed no threat to healthy adults,” said Renee Sharp, an analyst at the Environmental Working Group, a Washington, D.C.-based research and public-policy organization. “This new study shows that even very small levels of perchlorate in water or food can have a marked effect on thyroid levels in women. We can’t ignore this serious public health issue any longer.”

Perchlorate is a soluble anion associated with the solid salts of ammonium, potassium, and sodium perchlorate. It is commonly found in rocket propellant. The perchlorate problem is most acute in California because of that state’s high concentration of military bases and the prevalence of the aerospace industry, although reports of contamination have come from as many as 35 states. Perchlorate has been found to be a contaminant in surface and ground water, and varying levels of perchlorate have been found in drinking water, fruits, vegetables, grains, and even milk.

According to the Environmental Protection Agency, “Perchlorate interferes with iodide uptake into the thyroid gland. Because iodide is an essential component of thyroid hormones, perchlorate disrupts how the thyroid functions…. Impairment of thyroid function in pregnant mothers may impact the fetus and result in such effects as changes in behavior, delayed development, and decreased learning capability.” They’ve established an “official reference dose” for perchlorate (a daily exposure level that is not expected to cause adverse health effects in humans) at 0.0007 mg/kg/day. In light of the recent findings, the EPA will be asked to re-evaluate its standards for perchlorate in drinking water

“These salts are highly soluble in water,” notes the EPA, “and because perchlorate adheres poorly to mineral surfaces and organic material, it can be very mobile in surface and subsurface aqueous systems. Also, since it is relatively inert in typical groundwater and surface water conditions, perchlorate contamination may persist for extended periods of time.”

This entry was posted on Friday, October 6th, 2006 at 6:42 pm and is filed under Health Concerns, Toxic Substances.