Although a report by the National Academy of Sciences' suggests the problem is not grave, U.S. Sen. Dianne Feinstein (D-Calif.) wants the Environmental Protection Agency to "take immediate action to establish a drinking water standard for perchlorate," an oxidant that is used in rocket fuels.

Feinstein released a letter on Friday (Jan. 21) to EPA Administrator Michael Leavitt saying that the agency should act immediately now that the NAS study, "Health Implications of Perchlorate Ingestion" has been issued.

In a brief summary of its report, the NAS said perchlorate "has been detected in public drinking water supplies of over 11 million people at concentrations of at least 4 parts per billion (ppb). High doses of perchlorate can decrease thyroid hormone production by inhibiting the uptake of iodide by the thyroid. Thyroid hormones are critical for normal growth and development of the central nervous system of fetuses and infants... 

The summary went on to say that "the body can compensate for iodide deficiency, and that iodide uptake would likely have to be reduced by at least 75 percent for months or longer for adverse health effects, such as hypothryroidism, to occur.

" The report recommends using clinical studies of iodide uptake in humans as the basis for determining a reference dose rather than using studies of adverse health effects in rats that serve as EPA s basis," according to the official summary. "The report suggests that daily ingestion of 0.0007 milligrams of perchlorate per kilograms of body weight, an amount more than 20 times the reference dose proposed by EPA, should not threaten the health of even the most sensitive populations."

In her letter, Feinstein said she intends to introduce legislation "that would serve to address perchlorate contamination on a national level and require the EPA to promulgate a final federal drinking water standard by July 31, 2007 . I am aware of the customary timeline under the regulatory process. However, the EPA has been evaluating perchlorate as a contaminant for over 10 years and I am confident that it is prepared to move swiftly to establish a final standard by this date."

In a news release on the subject  issued in December 2004, the senator outlined the problem:

“In California, perchlorate has been found in more than 350 drinking water sources,” Senator Feinstein said then. “It has seeped into the Colorado River and last month, the FDA reported that perchlorate was detected at numerous locations around the country. This is not just a California problem. It is a national problem. 

"The FDA study, released in November, found perchlorate in 90 percent of lettuce samples taken in California, Arizona, Texas, Florida, and New Jersey and 101 of 104 milk samples taken at retail stores around the country. 

"A study by the Environmental Working Group, released in June, revealed the penetration of perchlorate into the food chain in 32 out of 32 milk samples found in California. The study also determined the average perchlorate concentration to be at 5.85 parts per billion, almost six times as high as the Environmental Protection Agency's provisional daily safe dose. 

“It is imperative that we reduce the perchlorate in our drinking water and protect Californians, especially pregnant women, the unborn, infants, and young children, from this threat to their health,” Senator Feinstein added. “There is much more work to do to determine the scope and the severity of the contamination across the country.” 

In that news release, the senator sketched the legislation she plans to introduce this year. It would:

• authorize $200 million to identify and clean up the sources of perchlorate, 
• provide grants for the research and development of better cleanup technologies, 
• create an Interagency Task Force to coordinate federal activities regarding water sources nationwide, 
• require EPA to set a national primary drinking water standard for perchlorate, and 
• make perchlorate polluting entities responsible for contamination cleanup efforts.