Exposure to human female hormones endangers male fish, species

Tue May 22, 11:17 AM ET

MONTREAL (AFP) - Tiny amounts of human female hormones in fresh water have a "feminizing" effect on male fish, and could endanger fish in the wild, a US-Canadian study released Tuesday found.

Researchers from Fisheries and Oceans Canada and the US
Environmental Protection Agency' name=c1> SEARCHNews News Photos Images Web' name=c3> Environmental Protection Agency over seven years added a small amount of synthetic estrogen to a man-made lake in northern Ontario, Canada, at a level similar to what is found in the waste water of major Canadian cities.

Synthetic estrogen in such waste water comes almost entirely from birth control pills.

The young male fish observed -- fathead minnow or Pimephales promelas -- produced less fertile sperm, egg proteins and in some cases eggs were found in their testicles, researchers said.

The same effects were seen in larger fish that feed on the minnow.
Earlier research had noted that male fish in contact with estrogen could suffer "feminizing" effects, but did not address the effect the changes would have on the survival of species.

The study, led by Canadian Karen Kidd and published in the Proceedings of the National Academy of Science, concluded that "the concentrations of estrogens and their mimics observed in fresh waters can impact the sustainability of wild fish populations."
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