More than two million women risk developing thyroid prob-lems and, their babies, a variety of birth defects, due to a rocket-fuel agent that has leached into America's drinking water and food supply, according to a report from the research and public watchdog Environ-mental Working Group (EWG), based in Washington, DC.
The chemical agent, known as perchlorate, has been leaking from 12,000 military bases across the US for years, contaminating the water in at least 22 states. Not only is drinking water affected, but also the food supply, as agricultural and dairy farms located near the bases are shipping contam-inated produce across the nation. Indeed, a Food and Drug Administra-tion (FDA) survey found that 93 per cent of all lettuce and milk sold in the US is contaminated with perchlorate (www.cfsan.fda.gov/~dms/clo4data.html).
The main target of this toxic chemical is the thyroid. The EWG's study, which analyzed new data from the US Centers for Disease Control (CDC), found that, among women who are deficient in iodine, exposure to perchlorate at even low levels could lower thyroid hormone to the extent of requiring medical treatment during pregnancy to avoid developmental damage to their babies.
Low thyroid-hormone levels, or sub-clinical hypothyroidism, can result in IQ deficit, developmental delay and, in severe cases, cretinism in the unborn infant. Since, according to the CDC data, 36 per cent of all American women are iodine-deficient, this means that more than one-third of women are at a heightened risk of perchlorate-related health effects.
The not-for-profit watchdog group translated the amount of perchlorate identified in the CDC study as poten-tially harmful as 5 ppb (parts per billion)-almost five times lower than the 24.5 ppb standard for cleanup of perchlorate-contaminated waste sites adopted by the US Environmental Protection Agency (EPA).
This means that the safety standards under consideration in California and New Jersey-6 ppb and 5 ppb, respectively-would also fail to protect women of childbearing age who don't get enough iodine in their diet. Even the more stringent drinking-water standard already adopted by Massachu-setts-2 ppb-cannot be considered safe as it would push some borderline hypothyroid women into the range of mild hypothyroidism, says the EWG. The bottom line is that millions of women across the country will be at an increased health risk from the toxic effects of the chemical. Yet, to date, there is still no national, enforceable standard for perchloratein drinking water.
And it's not just pregnant women and fetuses who are likely to be affect-ed. In a separate CDC study, research-ers tested more than 2800 urine samples around the country: perchlor-ate was present in every single case.
What's more, they discovered that children aged six to 11 had an average of 1.6 times more perchlorate in their urine than adults (J Expo Sci Environ Epidemiol, 2006 Oct 18; epub ahead of print). According to the EWG, although the study did not look at children under six, it raises concerns that infants and younger children may also be exposed to greatly elevated levels of per-chlorate. "This is especially true," it points out, "since infants and young children have much higher intakes of drinking water in proportion to their body weight-and the fact that the perchlorate has been detected in human breast milk at moderate to high levels (see box, page 21)."
As infants and children have higher iodine requirements than either adults or even pregnant women, it follows that they will be more likely to suffer from perchlorate-related changes in thyroid-hormone levels. Even more worrying, recent research shows that infants can suffer permanent neuro-logical damage from just short-term thyroid-hormone insufficiency (Ann NY Acad Sci, 2006; 1076: 168-90).
Other population groups-those who already have an underfunctioning thyroid, or are smokers (smoking can interfere with the thyroid's ability to utilize iodine) and/or are elderly-may also be more prone to the adverse effects of perchlorate. Indeed, a report from the National Academy of Sciences noted that for "pregnant women, infants, and children, and people who have low iodine intake or pre-existing thyroid dysfunction, the dose [of perchlorate] required to cause a de-crease in thyroid hormone production may be lower [than for non-pregnant adults]" (Committee to Assess the Health Implications of Perchlorate Ingestion, National Research Council. Health Implications of Perchlorate Ingestion. Washington, DC: The National Academies Press, 2005).
Safety in numbers?
Is there such a thing as a safe level of this chemical? So far, this question remains under debate-and reveals an enormous amount of political back-room manoeuvring. The EWG proposes that drinking-water standards for perchlorate should be set as low as possible-no more than 1 ppb. This amounts to roughly one drop of the chemical in an Olympic-size swimming pool. This is the same level proposed by the EPA back in 2002, in a draft assessment of perchlorate toxicity (EPA. Perchlorate Environmental Contamination: Toxicological Review and Risk Characterization. 2002; available at http://cfpub2.epa.gov/ncea/ cfm/recordisplay.cfm?deid=24002).
However, the US Department of Defense (DOD) and its contractors-with the help of the Bush administra-tion-wrestled the assessment away from the EPA, much to the Agency's surprise, and handed it over to the National Academy of Sciences (NAS)in 2003. Subsequently, the EPA deleted from its website the statement that 1 ppb is the draft safe level for perchlorate and, in 2005, adopted the NAS recommendations instead-a level more than 20-fold greater-with no public comment or review.
In 2003 and 2004, The Natural Resources Defense Council (NRDC), a US environmental action group, sent more than a dozen Freedom of Infor-mation Act requests to the EPA, DOD and the White House, asking for information on the extent of the national perchlorate contamination, its toxic effects and the agencies' activities regarding the chemical.
Eventually, after a number of lawsuits, the NRDC finally gained access to a number of important documents that they say "indicate that the NAS panel's recommendation was likely shaped by a covert campaign by the White House, the Pentagon and defense contractors to twist the science and strong-arm the academy."
Nevertheless, the government is still withholding thousands of records, including virtually all of the key papers documenting White House and Penta-gon efforts to influence the NAS. In fact, the government was required by the court to submit a Vaughn Index, a list describing each of the withheld documents. The NRDC says that this single-spaced list is more that 1500 pages long, an unparalleled volume of record-withholding in the organiza-tion's decades of experience with the Freedom of Information Act.
Another environmental group-Environment California-also alleges that the defence industry manipulated the NAS panel as it prepared to set risk levels for perchlorate. In a report released in December 2006 called The Politics of Rocket Fuel Pollution, Environment California investigated the activities of the Perchlorate Study Group (PSG), an industry-backed group responsible for much of the research into the health effects of perchlorate exposure. They reported that the PSG "worked to pressure" the NAS "to downplay the risks of rocket fuel pollution". The PSG includes manufacturers and users of perchlor-ate such as Aerojet, Lockheed Martin and Trontox (www.environmentcalifornia.org/ reports/clean-water/clean-water-program-reports/the-politics-of-rocket-fuel-pollution)
Moreover, Environment California alleges that the group also worked to influence professional organizations of physicians and researchers specializing in thyroid diseases such as the American Thyroid Association (ATA). PSG consultants issued statements through the ATA that were favourable to the defence industry, and presented industry research at ATA events, according to Environment California.
Indeed, in a statement on the ATA's website responding to the latest findings of the CDC, which show that even low levels of perchlorate can be harmful to millions of women and their babies, the association appeared to significantly downplay the implications for public health, noting that "several features of the study may limit the immediate application to guidelines for perchlorate exposure standards" (www.thyroid.org/professionals/publications/statements/06_12_13_perchlorate.html).
While the American government's agencies continue their campaign of damage limitation, millions of people across the country and, in fact, the world (through food that is imported from the US) could be at risk of poison-ing themselves-and the following generations-with every meal or sip of water that is consumed.
Rocket fuel in breast milk
Not only has perchlorate contaminated the water and food supply in America, it has also been found in breast milk. In a study published in 2005, researchers from Texas Tech University found perchlorate in the breast milk of every single woman tested. They also found the chemical in all but one of the dairy milk samples tested-but the average concentration of perchlorate in breast milk was five times higher than in the dairy milk.
The researchers measured 47 dairy samples from 11 states and 36 human breast-milk samples from 18 states. The average level in breast milk was 10.5 mcg/L (or parts per billion), with some samples having a concentration of perchlorate as high as 92 mcg/L (Environ Sci Technol, 2005; 39: 2011-7).
What to do
- UK residents
Although perchlorate contamination doesn't appear to be a problem in the UK, one area of concern is citrus fruits imported from America. Citrus fruits are often leaf-fertilized with Chilean saltpeter spray, known to contain 0.1-0.4 per cent perchlorate. Such products, grown from California to Florida, supply the entire US-and also the UK. So, it would be wise to be wary of your orange juice. Also, look out for other imported foodstuffs from the US.
- US residents
To find out if the water supply in your state is affected, visit the EPA website (www.epa.gov/fedfac/documents/perchlorate_map/nationalmap.htm).
- Bottled water may also be contaminated, so install a water filtration unit in your home that uses 'reverse osmosis'. See WDDTY vol 17 no 8 for more advice on water filtration.
- Go organic wherever possible when buying fresh produce.