The gender benders: are environmental 'hormones' emasculating wildlife? - includes related articles

Science News, Jan 8, 1994 by Janet Raloff

Other researchers have begun linking reproductive problems in salmon to relatively high concentrations of hormone-like contaminants. And at a conference sponsored by the U.S. and Canadian governments three years ago, PCBs in such fish were linked to dramatic declines in the reproduction of minks and otters around the Great Lakes.

Finally, University of Wisconsin scientists demonstrated two years ago that low prenatal exposures to dioxin femanized the behavior of male rats during adulthood-- and sharply reduced their production of sperm. Indeed, the researchers concluded, the developing male reproductive system appears to be more sensitive to the effects of this hormone-like toxicant that any other organ or organ-system studied (SN: 5/30/92, p.359).

Because we're only just getting to the basics in this field," Palmer says, even simple questions about the reproductive effects of environmental hormones for most species must go unanswered. But he suspects that biologists are going to have to move fast in finding those answers if some contaminated populations are to survive.

Toxic-pollutant concentrations in the environment have dropped to where they can seldom kill most adult animals outright, he says. However, in some species, he fears, "We may have gotten to a point where the adults look healthy but are so reproductively impaired that that population may already be extinct--and we're just waiting for the last remaining adults to die [of old age]."