A panel of scientists convened by the National Research Council found no persuasive evidence that chemicals in the environment are disrupting hormonal processes in humans or wildlife.
But the panel, funded in part by the U.S. Environmental Protection Agency, recommended research continue into so-called "hormonally active agents," including pesticides, PCBs and chemicals in plastics.
Acknowledging that high doses of some of the chemicals may pose a risk to humans and wildlife, the panel said the evidence was inadequate to suggest that low doses typically found in the environment pose any risk.
"The panel could not confirm the horror stories that have been spread about these chemicals over the last few years," said Bonner R. Cohen, senior fellow and environment specialist at the Lexington Institute in Arlington, Va.
Sandra Tirey, leader of the Chemical Manufacturers Association's Public Health Team, said, "The report is a significant step forward on an important public health issue."
But not everyone is satisfied with the report. "It's a little schizophrenic. It's so heavily balanced that it borders on not saying anything," said Peter de Fur, an environmental activist at Virginia Commonwealth University.
Since the early 1990s, some researchers and environmental activists have theorized that low levels of certain chemicals disrupt normal hormonal processes, and cause a wide variety of health problems in wildlife and humans, ranging from cancer to disorders in reproductive, developmental, neurologic and immunological systems.
Many of the chemicals have been released into the environment through industrial emissions or chemical and pesticide use. Some manufactured products such as plastic intravenous (IV) bags and plastic food wrap have also been cited as potential sources of certain chemicals.
Deerfield-based Baxter International came under fire earlier in the year for its use of polyvinyl chloride in some of its medical products, including plastic tubing and IV bags.
Scientific support for the theory, though, has been difficult to come by. After four years of scientific review and debate, the panel concluded that available data does not support associations between the chemicals in question and hormonally sensitive cancers, such as those of the breast, testicles, prostate and endometrium. Evidence of harm to humans from low-level exposure to the chemicals was also not persuasive for reproductive, neurologic or immunologic effects.
Claims of declining sperm counts have been hotly debated for years, but the panel concluded there was no evidence of a global decline in sperm counts, although some evidence points to declines in certain regions, particularly Europe. Whether those declines are linked to pollution is unknown, the report said.
The panel was also unable to explain biological processes through which chemicals would cause the effects alleged.
About claims that hormonally active chemicals have contributed to declines in some wildlife populations, including fish and birds of the Great Lakes and alligators in Florida, the panel concluded "It is difficult to determine a clear causal relationship between these changes and exposure to (chemicals) given all of the other environmental factors involved."
The panel, however, refused to dispose of the hormone-disrupter theory without more research.
But the call for more research has been questioned. "The endocrine-disrupter hypothesis has never been grounded in any reality," said Dr. Elizabeth Whelan, president of the American Council on Science and Health. "It is easy to call for more research in the absence of danger. I am now convinced that one of the major problems is that scientists are unwilling to use the four-letter word, 'safe.' "
"The call for more research was simply a sop thrown to committee activists in exchange for their consent to release the report," says Dr. Michael Gough, a former government scientist and adjunct scholar at the Cato Institute in Washington, D.C.
"Advocates of the hormone disruption theory blocked release of the report when they realized it wasn't going to reach the conclusions they wanted. This type of deal-making is unfortunate, but it's a reality of science-by-committee," Gough said.
Comments on this posting?
Click here to post a public comment on the Trash Talk Bulletin Board.
Click here to send a private comment to the Junkman.