Discovery News (Silver Spring, Md.: 11.3 million  monthly unique users)
"The Pill Off The Hook For River  Estrogen"
February 17

Until recently, humans took the blame for unusually high levels of  estrogen-like chemicals in rivers, lakes and streams. Some thought it was birth  control pills but other evidence pointed to agricultural wastes. But, new  research suggests a form of algae may be contributing to the problem, which can  cause males of some fish, amphibians, and reptiles change behaviors and even  develop female physical characteristics. Blue-green algae, or cyanobacteria,  caused responses in zebrafish similar to those caused by estrogen-like  chemicals, the results of the study were published in the journal  Environmental Science and Technology. The researchers found  that young fish exposed to blue-green algae showed a chemical marker known to  result from estrogen exposure. The marker didn't show up when the fish were only  exposed to the known toxin that the blue-green algae produce. So the scientists  think there must be a previously-unknown chemical released by the algae that  caused the estrogen-like effects. That means that algae blooms, or sudden large  bursts of algae growth, could have even greater health consequences for  animals