Monday, March 26, 2012

Endocrine Disrupting Chemicals Affective at Low Doses


Scientists Warn of Low-Dose Risks of Chemical ExposureBy Elizabeth Grossman, Yale Environment 360 26 March 12

[paraphrasing] Chemicals studied include BPA; commonly used pesticides, including atrazine and chlorpyrifos; methyl paraben, a preservative used in cosmetics and personal care products; triclosan, antibacterial agent used in soaps and toothpaste; nonylphenol, a detergent ingredient; the flame retardant PBDE-99; perchlorate, a fuel compound; and dioxin, an industrial and incineration by-product; DDT, and PCBs.
 
[excerpted] "the ...research, based on a review of 800 scientific studies, concludes that it is "remarkably common" for very small amounts of hormone-disrupting chemicals to have profound, adverse effects on human health. Hormone- disrupting chemicals, the paper explains, challenge a fundamental tenet of toxicology - "the dose makes the poison" - which contends that the greater the dose, the greater the effect. Hormone-disrupting chemicals don't necessarily behave like this. Significant health effects, the researchers say, sometimes occur at low rather than high doses.

"Whether low doses of endocrine-disrupting compounds influence human disorders is no longer conjecture, as epidemiological studies show that environmental exposures are associated with human diseases and disabilities," the paper's authors write. The study, published in the journal Endocrine Reviews, maintains that the low-dose and special dose-response effects of hormone-disrupting chemicals means that "fundamental changes in chemical testing and safety determination are needed to protect human health..."

"...A key concept of the paper is that endocrine-disrupting chemicals are non-monotonic, meaning that the responses of animals or people to the chemicals do not necessarily intensify or diminish based on the dose..."

This important  study Hormones and Endocrine-Disrupting Chemicals: Low-Dose Effects and Nonmonotonic Dose Responses, by Vandenberg et al  can be found here at at the journal, Endocrine Reviews:


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