New study links low levels of exposure to thyroid problems in
women
Morgan Hill – California Sens. Barbara Boxer and Dianne Feinstein on Wednesday sharply criticized the U.S. Environmental Protection Agency’s cleanup “guidance” for perchlorate in drinking water, writing in a letter to EPA Administrator Stephen Johnson that the guidance does not protect vulnerable pregnant women and children.
Even minute traces of the rocket-fuel chemical lowers essential thyroid hormones in women, the senators wrote, citing a study published this month by the Centers for Disease Control and Prevention.
“Given the serious health threat posed by widespread perchlorate exposure, we request that you take immediate steps to incorporate the information from the CDC study in a health advisory and new perchlorate standards and goals,” wrote the senators, requesting a response from the agency by next Monday.
Perchlorate contamination is found nationwide, with federal tests showing 160 public water systems in 22 states are contaminated with the chemical. Hundreds of South County wells were contaminated with perchlorate that leached into the soil at Olin’s now-defunct road-flare plant in Morgan Hill. The plume stretches south through San Martin and northeast of Gilroy. Throughout California, perchlorate has been found in 450 wells and other water sources.
In July, Massachusetts set the nation’s first drinking water standard for perchlorate of 2 parts per billion. The California Department of Health Services is considering a standard in drinking water of 6 ppb for perchlorate. A hearing on the proposal is scheduled for Oct. 30 in Sacramento. There is currently no federal drinking water standard for perchlorate, though the EPA has issued a cleanup “guidance” level of 24.5 ppb.
Boxer and Feinstein cited in their letter a study published Oct. 4 by the U.S. Centers for Disease Control and Prevention that shows even minute traces of perchlorate lowers essential thyroid hormones in women – particularly those with lower iodine intake. Thirty-six percent of U.S. women have iodine intake that falls into this category, according to the report. The toxic rocket-fuel chemical is commonly found in milk, fruit, vegetables and drinking water supplies nationwide. The senators also cited the concerns of the EPA’s Children’s Health Protection Advisory Committee, which in March stated the EPA’s guidance was “not supported by the underlying science and can result in exposures that pose neurodevelopment risks in early life.”
The EPA is currently reviewing Feinstein and Boxer’s letter, and will respond in detail, said EPA spokeswoman Jennifer Wood.
“The EPA is committed to continually examining perchlorate science to ensure that our policies best protect public health,” Wood wrote in an e-mail. “The EPA is interested in the CDC’s findings, although CDC scientists recommend that their study be confirmed with additional research. The EPA will review and analyze these new studies in conjunction with the body of available research that contributes to our understanding of perchlorate toxicity and exposure.”
Perchlorate is primarily used by the U.S. Department of Defense to make rocket and missile fuel. The inorganic chemical is also used in explosives, fireworks, road flares and airbag inflation systems. Most contamination comes from military bases. It is also widely found in produce, including oranges, grapes, melons, lettuce, tomatoes and spinach. Santa Clara County Agricultural Commission Greg Van Wassenhove said there’s a growing need for a risk assessment for perchlorate in irrigation systems.
The CDC team analyzed urine samples from more than 1,100 women for perchlorate, and then looked to see if perchlorate exposure could predict thyroid hormone levels. They found a significant link between perchlorate levels as low as 3 ppb. The federal “safe dose” level is more than 10 times this dose.
Tony Burchyns covers Morgan Hill for The Times. Reach him at (408) 779-4106 ext. 201 or tb*******@*************es.com.
