The EPA decided to act after scientific evidence suggested that low doses of hormone-mimicking chemicals are damaging to human health, more specifically human development and reproduction abilities. The agency will also look into whether the current testing methods and risk assessments should be reformed, depending on the results. According to the Scientific American, the report is expected to be ready by the end of next year and will be released by a national panel of academics.
The EPA website listed scientists from the FDA, the National Institute of Environmental Health Sciences' National Toxicology Program and the National Institute of Child and Human Development as taking part in the research. According to the website, the EPA is determined to base its decisions on sound scientific evidence and to develop the paper in an open and transparent process.
The question of whether chemicals that mimic estrogen, testosterone or other hormones are harmful has caused lengthy discussions among scientists. A report issued earlier this year concluded that even low doses did in fact have an impact. Over a period of three years, a team of researchers at Tufts University, led by Laura Vandenberg, reviewed hundreds of studies on the link between human health and endocrine-disrupting chemicals and found that small doses cannot be ignored.
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In their report the researchers claimed that the current tests on chemicals, which expose lab mice and rats to large doses of the chemicals and then extrapolate the effect of small doses in humans, is inadequate because there are effects that appear only when small doses are applied and are not present when bigger doses are used. Researchers call these "non-monotonic dose responses."
Professor Frederick vom Saal of the University of Missouri, a co-author of the study, said that it was about time the government took the problem of small doses extrapolation seriously. Vom Saal said that for too long federal agencies have been making assumptions about how safe hormone-like chemicals are without testing them at low levels. He noted that when using endocrine disruptors like bisphenol A (also known as BPA), there is no such thing as safe levels.
The report has finally caused enough concern among federal officials to start a new investigation on the matter. Vandenberg welcomed the news but pointed out that the government will need to look at two things separately – low dose and non-monotonic dose responses. Researchers believe that in order to get the full picture of the effects that those chemicals cause, the review needs to look at various doses, as low dose and non-monotonic dose responses are two very different concepts and they need to be addressed individually.
