When women take birth control pills, some of the hormones in the pills ends up in sewage effluent and waterways where it may be harming trout populations. Researchers now say that even short-term, low-level exposures to one such hormone, ethynylestradiol (EE2), can reduce a male trout's fertility by half.
Toxicologist Irv Schultz and his colleagues at the Battelle Marine Sciences Laboratory in Sequim, Wash., exposed three groups of adult male trout in tanks to different concentrations of ethynylestradiol for 2 months. All the trout exposed to 1,000 parts per trillion (ppt) of EE2 died of liver and kidney hemorrhages before the experiment's end. The two groups that were exposed to lower concentrations of the estrogen–10 and 100 ppt–appeared to remain healthy. However, further work showed EE2's effect on reproduction.