preventionisthecure.org

Dec. 13, 2012

"Spurred by mounting scientific evidence, the U.S. Environmental Protection Agency is initiating a new effort to examine whether low doses of hormone-mimicking chemicals are harming human health and whether chemical testing should be

Photo Credit: April G Hannan

overhauled. The EPA, responding to a report by a team of 12 scientists published in March, is collaborating with other federal agencies to assess whether traces of chemicals in food, cosmetics, pesticides and plastics affect human development and reproduction. As part of that review, they will evaluate whether current testing is capturing an array of effects linked to hormone mimics, and if the agency should alter its risk assessments. The federal scientists will complete a “state of the science” paper by the end of 2013. The scientists in the March report criticized the federal government’s decades-old strategy for testing chemicals – exposing lab rodents to high doses then extrapolating down for real-life human exposures. They said it is inadequate to protect people and urged reforms because hormone-like chemicals can have health effects at low doses that do not occur at high doses, a phenomenon called "non-monotonic dose response." “I’m thrilled they’re doing this and it’s desperately needed,” said Universty of Missouri scientist Frederick vom Saal. “Hopefully it won’t take long and we can stop asking whether there are low-dose effects and then deal with the fact that there are.”more.

(Environmental Helath News. 12/13/2012. http://www.environmentalhealthnews.org/ehs/news/2012/epa-low-dose)

A striking degree of abnormal cell growth Mammary tissue of control mice (left) and mice exposed as fetuses to

A striking degree of abnormal cell growth Mammary tissue of control mice (left) and mice exposed as fetuses to 1,000 mg per kg of mother’s body weight of MEHP, a common ingredient in plastics. (Black bar is 1 mm.) (Credit: Hixon Lab/Brown University)

1,000 mg per kg of mother’s body weight of MEHP, a common ingredient in plastics. (Black bar is 1 mm.) (Credit: Hixon Lab/Brown University)ScienceDaily (Mar. 16, 2012) — Many environmental and public health officials are concerned about the potential health effects of phthalates, which are common chemicals used to make plastics softer and more pliable. In the first study to examine what effect in utero doses of phthalates have on the reproductive system of mice, Brown University toxicologists found that extremely high doses were associated with significant changes, such as a shortened reproductive lifespan and abnormal cell growth in mammary glands.

Female mouse fetuses exposed to very high doses of a common industrial chemical that makes plastics more pliable develop significant reproductive alterations and precancerous lesions as they grow up, according to a new toxicology study conducted at Brown University.

The administered doses of MEHP, the chemical that results when animals metabolize the industrial phthalate DEHP, were much higher than any normal environmental exposure that people or animals would encounter, said Mary Hixon, assistant professor of pathology and laboratory medicine (research) in The Warren Alpert Medical School of Brown University and a study co-author.

"For these doses, you'd have to be eating the plastic or drinking the plastic," she said. "The real risk is probably minimal for most people."

But when toxicologists set out to determine the effect of a chemical on an organism, they often start with atypically high doses and work their way down to the levels where any adverse effects disappear. Until now, no one had done such a study on the effects of exposure to doses of MEHP in adult mice while they were still in utero.