Perchlorate
From Wikipedia, the free encyclopedia.
http://en.wikipedia.org/wiki/Perchlorate
Perchlorates are the salts of perchloric acid (HClO4). They occur both naturally and through manufacturing. They are commonly found in rocket fuel and explosives, often those used by the military. Ammonium perchlorate is a major ingredient of rocket fuel. They have also been used in airbags, fireworks, and Chilean fertilizers. Both potassium perchlorate (KClO4) and ammonium perchlorate (NH4ClO4) are used extensively within the pyrotechnics industry. Most perchlorate salts are soluble in water, giving strongly oxidizing solutions.
Perchlorates are a neurotoxin. They have been found to affect the thyroid gland in particular. When perchlorates enter the body, they block iodine uptake to the thyroid gland, which is needed to create thyroid hormones used by the body for metabolism as well as for growth and development in children. This can result in tumor growth on the thyroid gland. The chemical is particularly dangerous to women of childbearing age and developing fetuses, since it is known to cause mental retardation in unborn children as well as infants. Children up to 12 years old and people with hypothyroidism are also at serious risk. It is also believed that there may be a connection between perchlorates and the increase in learning disabilities over the past few decades.
Perchlorate pollution
Perchlorates have been found in both drinking water and groundwater in 35 states in the US according to the Environmental Protection Agency. In California, perchlorates were found in the water supply above the state's 2 microgram per liter (µg/L) (parts per billion, weight over volume (ppb w/v)) allowable level. In 2004, the chemical was also found in cow's milk in the area with an average level of 1.3 µg/L, which may have entered the cows through feeding on crops that had exposure to water containing perchlorates. These crops, which have been contaminated through soil and fertilizers containing perchlorates, included ones to be eaten by humans. In Massachusetts, perchlorates were found in groundwater in the area of Massachusetts Military Reservation on Cape Cod and other Department of Defense facilities. According to the Impact Area Groundwater Study Program [1] (http://www.groundwaterprogram.org/), the chemical has been detected as high as 5 µg/L in Massachusetts, well over the state regulation of 1 µg/L. As of 2004, towns that have been contaminated in Massachusetts include Bourne, Westford, Hadley, and Methuen.
As of 2004, the EPA has not yet made a nationwide regulation on the allowable level of perchlorates in water. They have suggested the level to be 1 µg/L, but this has been opposed by the Pentagon. The Pentagon has claimed that up to 200 µg/L should be allowed. The Pentagon has also asked the United States Congress to allow them to be exempted from environmental laws that cover the cleanup of explosive residues which cause perchlorate contamination.
On January 10, 2005, the National Academy of Sciences released a report prepared by the National Research Council that found, contrary to the EPA's preliminary findings, 20 ppb was safe for consumption by adults. The findings have met with controversy as the Natural Resources Defense Council released a series of documents obtained under FOIA that indicate a possible bias on the part of the committee designated to research the issue. Another organization, Environment California, released its own report, emphasizing the harmful effects of perchlorates on "expecting mothers, their developing fetuses and their infant children". It is too early to determine what, if any, regulatory impact the NAS study will have.
Ground Water & Drinking Water - Perchlorate
U.S. Environmental Protection Agency
http://www.epa.gov/safewater/ccl/perchlorate/perchlorate.html
There have been confirmed perchlorate releases in at least 25 states throughout the United States. EPA, other federal agencies, states, water suppliers and industry are working to address perchlorate contamination through monitoring for perchlorate in drinking water and source water and developing treatment technologies that can remove perchlorate from drinking water.
Safe Drinking Water Now
Perchlorate and Children's Health:
The Case for a Strong Cleanup Standard for Rocket Fuel in Drinking Water
Environment California Research & Policy Center
January 2005
http://environmentcalifornia.org/envirocalif.asp?id2=15344&id3=CE&
Executive Summary
In order to protect expecting mothers, their developing fetuses and their infant children, the California Department of Health Services (DHS) should set a final health standard for perchlorate in drinking water at one part per billion or less.
Perchlorate, the primary ingredient in solid rocket fuel, is emerging as a major contaminant of California’s food and water supplies. The U.S. Food and Drug administration recently documented widespread contamination in milk and lettuce from grocery stores in California and across the country. Many water suppliers in California have detected perchlorate in their wells at levels suggested by the U.S. Environmental Protection Agency (EPA) as unsafe.
Perchlorate contaminates the drinking water supply of 16 million Californians.
- State agencies have discovered perchlorate pollution in more than 350 water sources, including the Colorado River and hundreds of municipal wells.
- The bulk of the contamination was caused by the military, aerospace contractors and other users and manufacturers of explosive chemicals.
- Communities with contaminated water supplies include Riverside, Loma Linda, San Bernardino, San Fernando, Pasadena, Rancho Cordova, West Orange County, and Otay.
Perchlorate exposure threatens expecting mothers, developing fetuses and infant children.
- Perchlorate affects the thyroid hormone system at very low levels of exposure. It acts by preventing uptake of iodine into the thyroid gland, reducing the gland’s ability to produce enough hormone.
- Thyroid hormone and iodine are critical for normal brain development in fetuses and young infants. Children born to mothers with thyroid problems or iodine deficiency can have lower IQ, impaired learning, hyperactive behavior, delayed growth, or can suffer a range of serious neurodevelopmental problems, including mental retardation.
- Exposure to perchlorate during specific and important windows of time during the growth and development of a child increases the risk of neurodevelopmental disability.
Neurodevelopmental disabilities, like attention deficit and hyperactivity disorder (ADHD), are a serious and growing problem in California.
- Learning-disabled students increased 65 percent faster than the general school population from 1985 to 1999.
- Perchlorate exposure could be contributing to this trend in combination with exposure to a variety of other chemicals polluting the environment, such as toxic flame retardants, lead, mercury, and polychlorinated biphenyls (PCBs).
The evidence of perchlorate’s toxicity warrants a strong drinking water standard of one part per billion or less.
- Exposure to low levels of perchlorate in utero leads to changes in brain structure and behavior in infant rats.
- Humans are as sensitive as rats to iodine uptake inhibition by perchlorate.
After evaluating the full spectrum of available science on perchlorate, the U.S. Environmental Protection Agency and the states of Massachusetts, Maryland and New Mexico have recommended preliminary drinking water health guidelines of one part per billion or less to provide a margin of safety for developing fetuses and infants. Accounting for widespread exposure to perchlorate in the food supply and for the combined effects of other thyroid toxicants in addition to perchlorate would justify an even lower standard.
However, the state of California is unofficially moving forward with a final drinking water standard equivalent to the public health goal of six parts per billion issued in March 2004. The process used to arrive at the public health goal did not live up to the criteria established by California law, and a standard set at this level would be inadequate for several reasons:
• California EPA chose a single scientific study as the main basis for calculating a safe level. The study examined the effect of perchlorate on healthy adults exposed for a short period of time, as opposed to including other research involving fetal and newborn rats with long-term perchlorate exposure.
• California EPA applied an atypically small margin of safety to ensure protection of especially vulnerable people. Almost all established public health goals in California use a larger margin of safety.
• California EPA failed to consider how perchlorate may be interacting with other thyroid toxicants (like toxic flame retardants, nitrates, PCBs and other common environmental contaminants) to contribute to neurodevelopmental problems in children.
• A final standard of six parts per billion could leave the contamination of the Colorado River and nearly one-third of the polluted wells in California unaddressed.
In setting a final perchlorate standard, the state should use the weight of scientific evidence, including experiments showing neurobehavioral damage to infant rats exposed to small amounts of perchlorate in the womb, as well as considering the possible interaction of perchlorate with other toxicants. In addition, the state should set larger margins of safety to account for uncertainties in the vulnerability of fetuses and infants to long-term exposure to low levels of perchlorate. After taking these steps, the state should arrive at a drinking water standard for perchlorate of one part per billion or less, ensuring a comprehensive cleanup and providing a margin of safety for pregnant women, their developing babies and their infant children.
POLICY RECOMMENDATIONS
• The California Department of Health Services should set the drinking water standard for perchlorate at one part per billion or less.
• In addition, the State of California, local governments, and water suppliers should hold responsible parties fully liable for cleanup and for supplying replacement drinking water to affected communities. Congress should not exempt the Department of Defense.
• Congress should reinstate Superfund fees for polluting industries to ensure that contamination caused by now-bankrupt companies will be cleaned up.
• Federal and state agencies should require American Pacific, Kerr-McGee Chemical and other responsible parties to accelerate clean up of perchlorate contamination currently leaking into the Colorado River and local aquifers.
WHITE HOUSE AND PENTAGON BIAS
NATIONAL ACADEMY PERCHLORATE REPORT
January 10, 2005
Press contact: Erik Olson, Jennifer Sass, or Elliott Negin 202-289-2360
http://www.nrdc.org/media/pressreleases/050110.asp
On January 10, a National Academy of Sciences (NAS) panel released a report evaluating the potential health threats posed by perchlorate, a toxic rocket fuel ingredient. Documents obtained from a series of Freedom of Information Act requests and lawsuits against the White House, Department of Defense and the Environmental Protection Agency indicate that the panel was subjected to massive pressure to downplay the hazards of the chemical. This behind-the-scenes campaign included extraordinary involvement by White House and DOD staff to limit the scope of the NAS panel's inquiry and select the panelists, and collaboration among the White House, Pentagon and defense contractors to influence the panel.
There is still much that we do not know about this clandestine effort, because the White House, DOD and EPA have attempted to cover up their campaign to pressure NAS and to undermine efforts to address perchlorate pollution by unlawfully withholding or redacting an unprecedented number of documents that number in the thousands. What we do know is the White House, Pentagon, senior EPA officials and government contractors are working together to avoid cleaning up a toxic chemical that jeopardizes the health of millions of Americans.
For decades, the DOD and its contractors have used millions of pounds of perchlorate, often carelessly, contaminating water and food supplies across the country. It has been detected in drinking water supplies used by more than 20 million Americans, for example, and has recently been found in much of the milk and lettuce and other crops that the Food and Drug Administration and others have tested.1 Major lawsuits have been filed in California and other states against DOD contractors that contaminated drinking water supplies with perchlorate, triggering a protracted battle over how much they will have to clean up and whether low-level perchlorate exposure is associated with disease. Perchlorate is now known to hamper the thyroid gland's normal functioning, which can disrupt normal brain development in fetuses and infants.
The DOD has been blocking government efforts to address perchlorate for more than a decade, but in the last few years it has intensified its campaign in the face of new revelations about its toxicity. In January 2002, EPA issued for peer review its third public draft assessment of perchlorate's toxicity since 1992, recommending that 1 part per billion (ppb) was the safe level in drinking water.2 In response, the DOD and its contractors lobbied to stop the assessment process and, with the help of the White House, ultimately wrested the assessment from EPA and handed it to NAS in 2003, a move that many observers viewed as a stalling tactic. When the news media reported that the Bush administration had asked NAS to review the EPA risk assessment, it surprised the lead EPA scientists and staff who had been working on perchlorate for many years, according to documents NRDC obtained (read the email). (Pressure from the DOD and its contractors has been so successful that the EPA recently deleted from its Web site the statement that 1 ppb is the draft perchlorate safe level, although the highly technical document the agency used to reach that conclusion is still available. The previous version of EPA's website stating that 1 ppb is the draft safe level is available here; the "cleansed" version is currently posted on EPA's site.)
In 2003 and 2004, NRDC sent more than a dozen Freedom of Information Act (FOIA) requests to EPA, DOD and the White House requesting information on the decision to refer the perchlorate issue to NAS, as well as the extent of perchlorate contamination nationally, its toxic effects, and the agencies' activities regarding the chemical. After the agencies stonewalled -- for more than a year in some cases -- NRDC was forced to sue, and we recently obtained about 30 boxes of documents. But the White House and relevant agencies continue to withhold or to "redact" (black out) thousands more documents or sections of documents. (A single-spaced list of the withheld documents, the so-called "Vaughn Index" the government submitted to the court, is more than 1,500 pages long, an unparalleled volume of record-withholding in our decades of experience with FOIA). NRDC now will seek to obtain the rest of the documents from the agencies by court order.
Although NRDC is still organizing, reviewing and evaluating the thousands of documents we have obtained, we made the startling discovery that the DOD, its contractors, and senior White House officials have been involved in an extraordinary effort to manipulate the NAS perchlorate panel.
White House and Pentagon Manipulation of NAS 'Charge' on Perchlorate
Whenever the government asks NAS to address a scientific issue, it provides NAS a "charge" that outlines the scientific issues to be reviewed. This is essentially the NAS panel's roadmap for its evaluation, and is the central organizing document for the NAS review. Documents show that:
- Senior White House political officials actively participated
in reviewing the scientific charge sent to the NAS on perchlorate. While
the existence of these documents and their authors are known from the
Vaughn Index, the text of every White House record relating to this review
was either redacted in its entirety, or the entire document was withheld.
[See OMB Vaughn index, January-February 2003, document number 2003-1-134;
February-March 2003, document numbers 2003-1-306 and 2003-1-307; February-March
2003, document numbers 2003-3-355; 2003-3-358; 2003-3-359.] For example,
John Graham, the head of the White House Office of Management and Budget's (OMB) regulatory
review office, personally commented on the highly technical charge to
the NAS. According to the Vaughn Index (See, for example, OMB Vaughn
index, January-February 2003, document number 2003-1-135; March 2003,
document number 2003-1-403; April 2003, document number 2003-1-591; January-February
2003, document number 2003-2-167; May 2003, document number 2003-2-1112;
November-January, document numbers 2003-3-61; 2003-3-64; January-March
2003 document number P-549), other White House officials also were
involved at varying levels in the review and debate on the NAS panel
and charge, including:
- Mitch Daniels, director, White House OMB
- Nancy Dorn, deputy director, White House OMB
- Philip Perry, general counsel, White House OMB
- James Connaughton, chair, White House Council on Environmental Quality (CEQ)
- Elizabeth Stolpe, associate director, White House CEQ
- Paul Noe, White House OMB, Office of Information & Regulatory Affairs
- Nancy Beck, White House OMB, Office of Information & Regulatory Affairs
- Daryl L. Joseffer, White House OMB
- James Laity, White House OMB, Office of Information & Regulatory Affairs
- Margo Schwab, White House OMB, Office of Information & Regulatory Affairs
- Paul Anastas, assistant director, White House Office of Science & Technology Policy
- Edna Curtin, White House OMB
- Dennis Deziel, White House CEQ
- Claudia Abendroth, White House OMB
- Dana Perino, communications director, White House CEQ
- Kathie Olson, associate director, White House OSTP
- Stanley Kaufman, deputy associate administrator, OMB
NRDC finds it startling and disturbing that senior White House officials reviewed and apparently edited a highly technical document charging NAS with evaluating detailed scientific questions. While the existence of these edits and their authors are known from the Vaughn Index, the text of every White House document relating to this review was redacted in its entirety, or the entire document was withheld.
- Perchlorate manufacturers and users (defense contractors) who
were facing enormous potential liability for perchlorate contamination
heavily lobbied the White House. The White House withheld information
on a meeting with Lockheed-Martin regarding perchlorate, and the Pentagon
withheld "talking points" for the White House developed by
Kerr-McGee, another perchlorate industry giant. [See OMB Vaughn Index,
February 2001-June 2002, document number 2001-36; DOD Vaughn Index, DOD
15, document number 15-3.]
- DOD officials also actively participated in developing
the NAS charge questions and apparently objected to portions of the NAS
Statement of Work (SOW), the document describing NAS's detailed
plans for conducting its scientific inquiry. Again, while the existence
of the Pentagon edits and objections is noted in the Vaughn Index, those
documents were withheld or entirely redacted. The Pentagon even refused
to divulge the authors or recipients of the documents, a clear violation
of longstanding FOIA law. For example, the Pentagon withheld documents
titled "Questions to the NAS in reference to perchlorate health-based
research data" [See DOD Vaughn Index, DOD 38] and "Email with
six attached emails discussing the EPA-NAS contract, inconsistencies
with the SOW and NAS charge questions that had been prepared…" [See
DOD Vaughn Index, DOD 19].
- The Pentagon withheld documents showing that it worked
with perchlorate polluters to lobby the White House. For example, as
noted above, it withheld "Talking points for OIRA [the White House
OMB's Office of Information and Regulatory Affairs] on Perchlorate Process
Issues as relayed by Kerr-McGee personnel." These "talking
points" were provided by Kerr-McGee, formerly the largest manufacturer
of perchlorate and owner of a perchlorate plant in Nevada that has contaminated
drinking water supplies used by millions of people. [See DOD Vaughn Index,
DOD 15, document number 15-3.]
- The final charge questions EPA sent to NAS closely track Pentagon and DOD contractors' allegations about the deficiencies in EPA's risk assessment, such as allegations that the human body "adapts" to perchlorate, that the perchlorate animal studies done for DOD and the perchlorate industry that EPA relied upon are flawed, and that perchlorate poisoning should not be a problem because iodine deficiency allegedly is rare in the United States. None of the issues raised by public health, environmental, or other experts who expressed concerns that EPA has underestimated perchlorate's risks were specifically included in the charge to NAS.
White House, DOD and Contractor Manipulation of NAS Panel Membership
An NAS panel is only as objective, independent and reliable as its members, but NRDC has uncovered evidence that the White House, Pentagon and DOD contractors sought to manipulate the panel's membership to place "friendly" scientists on it. Generally when EPA requests a review from NAS, EPA scientific staff may suggest a few experts in the field as potential panelists, but we are not aware of any examples of previous White House political involvement in such issues.
In this case, we have uncovered evidence that White House officials were involved in discussions about who should be appointed to the NAS panel. (See OMB Vaughn Index, June 2003, document number 2003-1-1041; May-August 2003, document number P-316) The White House has withheld or redacted the text of every document in which White House staff discussed who should be appointed to the panel or the makeup of the panel.
Pentagon officials also apparently were involved in naming members of the NAS panel. For example, DOD withheld documents titled "Discussion of meeting in order to develop list of candidates to the NAS panel," [See DOD Vaughn Index, DOD 13 "Discussion of Nominations to NAS Board on Perchlorate," [DOD 31] and "Attached documents titled 'NAS/NRC Perchlorate Panel Selection Dynamics' [DOD 17.] Again the Pentagon refused to release the documents, or even the authors and recipients of them, in clear violation of FOIA law.
When the 15-member NAS perchlorate panel was named, [click here for committee list] not surprisingly it included several close allies of the DOD and industry. The panel, first announced in July 2003, included:
- Richard Bull was named a panelist despite his ongoing
work as a paid expert witness for Lockheed-Martin in litigation involving
perchlorate and other contamination of drinking water in California.
[December 18 Letter Perchlorate Ingestion etc.; NRDC Letter to Muir February
2004; NRDC Letter to Alberts October 2003] After repeated objections
from NRDC and many others, and after he publicly took the position at
an industry-funded meeting that low-level perchlorate exposure was innocuous
- while the NAS review was ongoing - Bull finally resigned in June 2004,
late in the NAS deliberation process.
- Charles Capen remains on the NAS panel. He was a paid
consultant on perchlorate issues to the aerospace industry-funded organization
Toxicology Excellence in Risk Assessment (TERA). [December 18
Letter Perchlorate Ingestion etc.; NRDC Letter to Muir February 2004;
NRDC Letter to Alberts October 2003],
- James Lamb, a private consultant at the Weinberg Group,
remains on the NAS panel. The Weinberg Group describes itself as follows: "For
twenty years, leading companies have depended on the Weinberg Group when
their products are at risk. Our technical, scientific and regulatory
experts deliver the crucial results that get products to market and keep
products on the market. The Weinberg Group has successfully partnered
with leading companies from around the world in the pharmaceutical, biotechnology,
medical device, chemical, consumer product, food and cosmetic industries."[Click here for
the Group's website.]
- Michael McClain worked for pharmaceutical giant Hoffmann-LaRoche for many years, and has since done extensive industry consulting. McClain's NAS biography was revised after questions were raised about the lack of disclosure of panelists' conflicts of interest. The final version states: "He reviewed scientific studies on perchlorate for private clients and provided comments to the EPA Peer Review Panel on Perchlorate in February 1999."[See biography here.]
Industry & Pentagon Lobbying of NAS
Since the NAS panel convened, defense contractors and their allies at the Pentagon and NASA have been heavily lobbying NAS. They have been in regular contact with NAS, and have submitted dozens of documents, letters and emails, and hundreds of pages of new, generally unpublished data, studies and reviews to the NAS panel, right up to October 2004, when the panel was concluding its deliberations. [See Public Access Materials.] For example, the DOD contractors' Perchlorate Study Group funded, and DOD sponsored, a one-sided "Perchlorate State of the Science" review conference in Nebraska, and submitted to NAS the extensive summary of the conference that claims to represent the "consensus" view of "independent" scientists. [See University of Nebraska PSG review.]
EPA Sets Perchlorate Guideline
By Amit Asaravala
02:00 AM Feb. 19, 2005 PT
http://www.wired.com/news/technology/0,1282,66661,00.html
Adults can tolerate nearly 25 times more of the potentially toxic chemical perchlorate in their drinking water than previously thought, the U.S. Environmental Protection Agency said on Friday.
The announcement marks the first time the EPA has issued an official guideline on how much perchlorate humans can safely ingest.
Environmental groups have been pushing for such guidelines since 1997, when the chemical -- commonly used in rocket fuels and explosives -- was found to contaminate water sources nationwide. More recently, perchlorate has been detected in the majority of the nation's milk and lettuce supply. High concentrations of the chemical are thought to disrupt the thyroid gland, which regulates metabolism and is linked to the development of motor skills in children.
According to the new guideline, humans can consume up to 0.7 micrograms of perchlorate per day for each kilogram of body weight without experiencing "adverse health effects." Based on the assumption that a 70-kilogram (154-pound) adult drinks 2 liters of water each day, the EPA estimates that 24.5 parts of perchlorate to 1 billion parts of water is a safe limit for water quality.
The figures are based on a report by the National Academy of Sciences, which examined several studies on the effects of perchlorate in humans and rats.
The EPA said it will use the first figure -- 0.7 micrograms per kilogram per day -- to help determine the level of cleanup necessary at contaminated Superfund sites.
The second figure -- 24.5 parts per billion -- will be used to guide further discussions about an official standard for water quality. This worries many environmental groups that have been pushing for a standard as low as 1 ppb, which they say would protect those who are most likely to be affected by perchlorate.
Setting the water-quality limit at the lowest possible level is not so easy, however. The aerospace and defense industries argue that an unnecessarily low limit could cost them billions of dollars in excess cleanup costs. Most of the perchlorate contamination in the United States has come from leaks or dumps at aerospace and defense sites, according to the National Academy of Sciences.
"The question now is whether the agency will protect all Americans, including children, from rocket fuel in drinking water, or cave to pressure from defense contractors who have polluted our drinking water," said Renee Sharp, senior analyst for the Environmental Working Group, in a statement released Friday.
In a phone interview Friday, EPA spokeswoman Cynthia Bergman stressed that 24.5 ppb is just a preliminary figure and added that it was based on the findings of the National Academy of Sciences.
"We had asked NAS to weigh in on this issue and they have," she said. "We're going with what they recommended."
Rocket Fuel in Milk, Lettuce
By Amit Asaravala
03:04 PM Nov. 30, 2004 PT
http://www.wired.com/news/technology/0,1282,65884,00.html
A large portion of the United States' milk and lettuce supply may be contaminated with potentially unsafe levels of a toxic chemical used in rocket fuel, according to data released by the Food and Drug Administration on Monday.
The "data" [broken link, was: http://www.cfsan.fda.gov/~dms/clo4data.html], part of a preliminary survey of milk and lettuce in 15 states, revealed perchlorate contamination in nearly 94 percent of reviewed samples. The results echo earlier findings by the Environmental Working Group, a nonprofit watchdog that issued a warning about perchlorate contamination in California-produced milk in June.
"The study confirms what we and some other people have been saying for a while -- that perchlorate is not only a problem in areas with known water contamination but for anyone who eats food grown in the U.S.," said Bill Walker, vice president of the Environmental Working Group's West Coast operations.
Perchlorate is both a naturally occurring and man-made chemical. It is used by the aerospace and defense industries to help rocket fuel burn. In humans, high concentrations can disrupt the thyroid gland, which regulates metabolism and is linked to the development of motor skills in children.
Because the long-term effects of small concentrations of perchlorate on humans are still unknown, both the FDA and the Environmental Working Group cautioned consumers not to draw the conclusion that they should stop drinking milk or eating lettuce.
"At this point we don't know if there is any risk," said an FDA spokeswoman. "Therefore, we're telling consumers to continue to eat a well-balanced diet. We don't want people to alter their diet in ways that make them think they're removing perchlorate, when they're really removing the healthy benefits of those foods."
In its survey, the FDA found an average concentration of 5.76 parts per billion of perchlorate in the 104 milk samples it studied. In 128 samples of green leaf, red leaf, iceberg and romaine lettuce, the agency found an average concentration of 10.49 parts per billion.
Federal and state agencies are still debating just how much perchlorate is acceptable in human diets. California health officials recommend that drinking water not exceed more than 6 parts per billion of perchlorate. The U.S. Environmental Protection Agency, meanwhile, recommends a stricter 1 part per billion.
"It's subtle," said Walker. "It's not like you're fine today if you get 6 parts per billion (of perchlorate in milk) and then tomorrow you drink a glass with 7 parts per billion and suddenly you're sick."
He added, however, that people with existing thyroid problems and pregnant women should monitor the total amount of perchlorate they ingest each day.
"We found that there are some people out there -- like the 1.6 million people of child-bearing age -- who are eating a diet very heavy in lettuce," he said. "This could be exceeding the EPA's recommended safe dose."
Though the FDA study didn't explore how perchlorate gets into lettuce or milk, scientists believe it enters the water stream through industrial leaks. It is then thought to be taken up by, and concentrated in, plants and animals.
The National Academy of Sciences is currently reviewing the EPA's assessment of the risks of perchlorate. A report is expected in Jan 2005. The FDA said it would wait until then to decide whether or not to enforce limits on the amount of the chemical that can appear in food products.
Rocket Fuel Found in Moo Juice
Associated Press
02:19 PM Jun. 22, 2004 PT
http://www.wired.com/news/medtech/0,1286,63948,00.html
SAN FRANCISCO -- Young children and pregnant women who drink milk from California cows may be exposed to unsafe levels of a toxic chemical used in rocket fuel, according to a new study by an environmental group.
The study released Tuesday by the Environmental Working Group comes as state and federal regulators consider setting new standards to regulate perchlorate -- the explosive ingredient in missile fuel that has been linked to thyroid damage.
"Perchlorate exposure is more widespread than we have been led to believe," said Bill Walker, vice president for the West Coast office of the EWG, a research and advocacy organization based in Washington, D.C.
The EWG did not call for Californians to stop drinking milk or giving it to their children, but said it does advocate tougher standards for perchlorate.
Perchlorate has been found in drinking water in more than 20 states, including California, which has extensive ties to the military, defense industry and the space program. The chemical has been detected in the Colorado River, the major source of drinking water and irrigation in Southern California and Arizona.
Researchers are divided about the effects of perchlorate on mental development and what exposure levels are safe.
In March, California health officials concluded that perchlorate could be dangerous at levels above 6 parts per billion in drinking water -- a level that could be used later this year to set the nation's first state standard.
But U.S. Environmental Protection Agency officials, and some environmental groups, say that standard would be too weak. The EPA advocates a standard of just 1 part per billion.
The new study on milk was based on laboratory tests the EWG commissioned as well as unreleased tests by the California Department of Food and Agriculture.
The EWG tests, conducted by researchers at Texas Tech University, found the chemical in 31 of 32 samples from milk purchased at grocery stores in Los Angeles and Orange counties. The average level of the chemical was 1.3 parts per billion.
The EWG said the Food and Agriculture Department tests found an average level of 5.8 parts per billion of perchlorate in 34 samples it tested from milk silos in Alameda, Sacramento and San Joaquin counties.
Department officials confirmed those results, but spokesman Steve Lyle said the findings didn't show any need for consumers to drink less milk.
"At this point, there is not enough information to suggest that eating foods with low levels of perchlorate poses a significant health concern," Lyle said.
The EWG study didn't determine how the chemical ended up in cows' milk, but perchlorate has been found in many of the state's water sources, which are used to irrigate farmland and grow crops fed to cows.
California's dairy industry will work with state and federal officials to find out how perchlorate is getting into milk and how to remove the chemical, said Michael Marsh, CEO of the Western United Dairymen, which represents the state's $4.5 billion dairy industry. But Marsh said there is a "paucity of science" showing perchlorate's harmful effects on human health.
A recent study by the University of California at Irvine found that healthy adults were not harmed by levels as high as 100 parts per billion of perchlorate. But the study did not draw conclusions about perchlorate's impact on pregnant women, children and infants.
GRISTMILL
Perchlorate
Posted by Dave Roberts at 8:48 AM on 20 Jan 2005
http://gristmill.grist.org/story/2005/1/20/84850/0192
