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Taking on Tens of Thousand Chemicals

Air Date: Week of

Under a congressional mandate, the EPA (Environmental Protection Agency) Endocrine Disrupter Screening and Testing Advisory Committee is developing criteria to determine which chemicals are harmful. The committee just met in Washington, D.C. and managed to compromise on how to go about testing some ten thousand chemicals. Living on Earth's Daniel Grossman was there and reports.


CURWOOD: This is Living on Earth. I'm Steve Curwood. Researchers have shown that some synthetic chemicals can cause animals to develop abnormalities. Like male alligators with female characteristics. Other studies show that women who eat fish laced with so-called endocrine disrupting chemicals tend to bear children who are more aggressive and have lower IQs. Right now, these problems are not a trigger for regulatory action. But under a Congressional mandate, the EPA Endocrine Disruptor Screening and Testing Advisory Committee is developing criteria to determine exactly which chemicals are harmful. The committee just completed a framework for the process in Washington, DC. Living on Earth's Daniel Grossman was there.

GROSSMAN: In mid-1996, with public concern about endocrine disrupting chemicals mounting, the EPA brought together a high-level advisory committee to figure out which chemicals were the bad actors. The assignment was a tall order, according to Sheldon Krimsky, a professor of environmental policy at Tufts University.

KRIMSKY: Potentially, there are 75,000 chemicals, and that's a substantial number. So this process of EPA is to decide how we're going to set priorities on these tens of thousands of chemicals. It's a big job. And it's never been done.

GROSSMAN: After a year of deliberations, the group has come up with a scheme for giving priority to substances most likely to be harmful. And they've crafted a 2-tier testing process. Tier 1 includes a battery of 7 tests designed to winnow out those chemicals that don't pose a risk, before going on to much more time-consuming and expensive Tier 2 tests on mammals and other animals.

(Ambient voices in a crowded room; a man says, "...we'll get started."

GROSSMAN: As the Washington session got underway, a number of critical issues divided committee members. First, how to define the term "endocrine disruption."

MAN: And I'll direct your attention to the eleventh line down, "Chemicals that irreversibly disrupt normal endocrine functioning and thus organogenesis due to..."

GROSSMAN: Some members, principally from industry, said endocrine disruption should mean an adverse effect, like a reproductive problem or a birth defect. Other members argued this definition would exclude subtle effects like increased hormone levels or unusual organ growth, which might initially appear insignificant but turn out to be important as scientific evidence mounts. Another sticking point was whether to test chemicals just at high doses or at low doses as well. For years regulators have subjected test animals to high doses, assuming that smaller exposures have less pronounced effects. But Professor Frederick vom Saal says with endocrine disruptors, sometimes just the opposite occurs.

VOM SAAL: We took hormones and synthetic chemicals and tested them over a very wide dose range, and demonstrated that instead of getting a bigger and bigger response as we put in more and more of the chemical, we at first got a very big response and then as the dose got higher and higher, we got a lower and lower response.

GROSSMAN: By the end of the 3-day meeting, a consensus emerged on the most important issues. A compromise was struck over how to define endocrine disruption. Meanwhile, industry accepted the idea of low-dose testing. And environmentalists agreed manufacturers could skip some tests under carefully defined conditions. Committee member Dr. Ted Schettler says he's pleased by the session's progress, but he warns that the problem of identifying chemicals of concern is far from solved.

SCHETTLER: We decided early on that we were only going to deal with estrogens, androgens, and thyroid hormones, and chemicals that interfered with those three hormone functions. There are many other hormones, many other growth factors, that we haven't even begun to talk about.

GROSSMAN: Over the next month committee members will hone the language debated in Washington. They meet again in March to hammer out a report to be reviewed by the EPA's Scientific Advisory Board. The Agency is scheduled to complete its plan for screening endocrine disrupting chemicals by August. For Living on Earth, I'm Daniel Grossman.



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