US Centers for Disease Control and Prevention (CDC) recently reported that scientists found measureable levels of mercury in most of the participants taking part in a nationally representative health and nutrition survey. This finding comes from the CDC's "Fourth National Report on Human Exposure to Environmental Chemicals", which, according to the federal agency, is "the most comprehensive assessment to date of the exposure of the US population to chemicals in our environment".
The Fourth Report includes results from surveys covering 1999 - 2000, 2001 - 2002, and 2003 - 2004 in which scientists measured total mercury in the blood of over 8,500 participants aged one year and over taking part in NHANES during 2003 - 2004, and mercury in the urine of over 2,500 participants aged 6 years and over, in the NHANES 2003 - 2004.
Total blood mercury mainly assesses methylmercury exposure, while urine mercury is a measure of inorganic mercury exposure. You need to measure both blood and urine levels of mercury to assess how much is in the body.
The CDC scientists found or concluded that:
An international team of researchers detected low concentrations of PCBs in snow samples taken at an altitude of 6200 metres in the Aconcagua Mountain in the Andes; they are among the highest traces found anywhere in the world of these substances, which have been banned since 2001.
Polychlorinated biphenyls (PCBs) are among the 'dirty dozen' persistent organic pollutants banned worldwide under the Stockholm Convention. Until the 1980s, PCBs were used primarily in transformers and capacitors and as hydraulic fluids and diluents. As well as causing chronic effects like acne, hair loss and liver damage, PCBs are also a suspected cause of male infertility. The toxin also represents a danger to a large number of animals because it accumulates in fatty tissue and is passed on via the food chain.
Of the 84,000 chemicals in commercial use in the United States – from flame retardants in furniture to household cleaners – nearly 20% are secret, according to the Environmental Protection Agency, their names and physical properties guarded from consumers and virtually all public officials under a little-known federal provision.
The policy was designed 33 years ago to protect trade secrets in a highly competitive industry. But critics -- including the Obama administration -- say the secrecy has grown out of control, making it impossible for regulators to control potential dangers or for consumers to know which toxic substances they might be exposed to.
Under the 1976 Toxic Substances Control Act, manufacturers must report to the federal government new chemicals they intend to market. But the law exempts from public disclosure any information that could harm their bottom line.
Government officials, scientists and environmental groups say that manufacturers have exploited weaknesses in the law to claim secrecy for an ever-increasing number of chemicals. In the past several years, 95% of the notices for new chemicals sent to the government requested some secrecy, according to the Government Accountability Office. About 700 chemicals are introduced annually.
Some companies have successfully argued that the federal government should not only keep the names of their chemicals secret but also hide from public view the identities and addresses of the manufacturers.
"Even acknowledging what chemical is used or what is made at what facility could convey important information to competitors, and they can start to put the pieces together," said Mike Walls, vice president of the American Chemistry Council.
Although a number of the roughly 17,000 secret chemicals may be harmless, manufacturers have reported in mandatory notices to the government that many pose a "substantial risk" to public health or the environment. In March, for example, more than half of the 65 "substantial risk" reports filed with the Environmental Protection Agency involved secret chemicals.
First Published in December 2009
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