WASHINGTON — Following a published report that the Bush Administration is holding up a study that shows most Americans carry a toxic rocket fuel chemical in their bodies at levels close to federal safety limits, Environmental Working Group (EWG) is calling for the immediate release of the study so EPA and state agencies can take steps to protect the public.
Risk Policy Report, an independent newsletter, reported Feb. 28 that the White House Office of Science & Technology Policy is pressuring the Centers for Disease Control to delay the release of a study that tested for perchlorate in human blood samples from the National Health and Nutrition Examination Survey (NHANES). An EPA source told the newsletter that CDC has found levels of perchlorate that "leave no margin of safety" for the public, compared to EPA's current risk limit.
Perchlorate, the explosive ingredient in solid rocket fuel, has contaminated drinking water and soil in at least 35 states, with most of the known contamination coming from military bases and defense contractors. Tests by EWG, academic scientists in Texas and Arizona, state officials in California and the U.S. Food and Drug Administration have found perchlorate in milk, produce and many other foods and animal feed crops from coast to coast. Perchlorate is a thyroid toxin, and animal tests show that even small amounts can disrupt normal growth and development in fetuses, infants and children.
The NHANES study is a followup to a CDC study last year that found perchlorate in the urine of every one of 61 Atlanta residents tested, even though concentrations of perchlorate in the cityÕs drinking water are very low. Last year, scientists at Texas Tech University also found perchlorate in every sample of human milk from 36 mothers.
In a letter to Dr. Julie Gerberding, director of the CDC, EWG Senior Vice President Richard Wiles said the results of the study of Atlanta residents "indicate that food is likely a major source of perchlorate exposure, and that perchlorate exposure is likely to be widespread in the general population."
Although the EPA has no timetable for developing a national drinking water standard for perchlorate, both Massachusetts and California are moving forward with their own safety standards. The proposed standards — 1 part per billion in Massachusetts and 6 ppb in California — are far below EPA's recently adopted risk limit of 24.5 ppb, which is a level used as a guidance for cleaning up perchlorate- contaminated sites. When the EPA announced the risk limit, it acknowledged the need for "national guidance on relative source contribution" — exactly the information the NHANES data could provide.
"In the absence of national safety standards, the CDC should not be sitting on data so clearly needed to protect the public from a chemical that appears to be widespread in drinking water and food," wrote Wiles. "The NHANES perchlorate data should be released immediately."
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EWG sent the following letter to the CDC director on March 2.
March 2, 2006
Dr. Julie Gerberding, Director
Centers for Disease Control
1600 Clifton Road, NE
Atlanta, GA 30333
Dear Dr. Gerberding:
The Environmental Working Group (EWG) is a not-for-profit watchdog organization that works to protect environmental and public health as well as scientific integrity. Since 2000, we have extensively studied perchlorate contamination of the nation's food and drinking water. We have documented widespread water and soil contamination, conducted groundbreaking tests that found perchlorate in supermarket produce and milk, and have repeatedly called on the Environmental Protection Agency (EPA) to set a national drinking water standard that fully protects fetuses, children and other sensitive populations, and adequately considers all potential sources of exposure.
We were awaiting with great interest the results of CDC's project to analyze National Health and Nutrition Examination Survey (NHANES) samples for perchlorate. As the first phase of that work, CDC tested for perchlorate in the urine of 61 Atlanta residents. The results, published last year in Analytical Chemistry, found perchlorate in the urine of each person tested, even though concentrations of perchlorate in the city's drinking water are very low (about 0.2 parts per billion). These findings are important because they indicate that food is likely a major source of perchlorate exposure, and that perchlorate exposure is likely to be widespread in the general population.
The Atlanta tests were not the only recent signs that prompt action is called for to protect the public. Last year, scientists at Texas Tech University reported finding perchlorate in human milk from 36 mothers at levels up to 92 parts per billion. In January, the EPA issued a new perchlorate cleanup guidance instructing risk assessors to base exposure "contributions from non-water sources" on "site-specific data until further national guidance on relative source contribution is developed." The EPA, state environmental agencies and the public need more information on perchlorate exposure levels — exactly the data that CDC's NHANES study was designed to provide.
Consequently, we were alarmed and dismayed to read in Risk Policy Report (Feb. 28) the article "Stalled CDC Study Shows Human Perchlorate Levels Near EPA Safety Limits:"
White House officials are delaying the release of landmark biomonitoring research conducted by scientists at the Centers for Disease Control & Prevention (CDC) that shows most Americans carry perchlorate in their bodies at levels close to safety limits set by EPA, according to EPA and other government health officials.
The article reports that the White House Office of Science & Technology Policy has pressured the CDC to delaying its release of the NHANES perchlorate study. The study is said to have been completed last fall, and according to an unnamed Food and Drug Administration official, the exposure levels found in the study are close to EPA's current risk limit of 24.5 parts per billion perchlorate in drinking water. This EPA risk limit, which is not an enforceable safety standard, is of course well above the 1 ppb level that is being considered by Massachusetts and the 6 ppb Public Health Goal adopted by California. This is all the more troubling if, as an EPA source told Risk Policy Report, "EPA's current perchlorate policies leave no margin of safety" for the public.
This is unacceptable. In the absence of national safety standards, the CDC should not be sitting on data so clearly needed to protect the public from a chemical that appears to be widespread in drinking water and food. The NHANES perchlorate data should be released immediately.
Thank you for your attention to this important matter.
Sincerely,
Richard Wiles, Senior Vice President
Environmental Working Group
