Contraceptive pills and cleaning chemicals that get flushed down the toilet are turning male fish into females, a new study indicates.
Charles Tyler, a professor at the University of Exeter in the UK, said that male river fish are increasingly displaying more feminine characteristics, such as reduced sperm, and are also producing eggs now due to the chemicals entering their natural habitat.
We are showing that some of these chemicals can have much wider health effects on fish that we expected,
Tyler said. “Using specially created transgenic fish that allow us to see responses to these chemicals in the bodies of fish in real time, for example, we have shown that estrogens found in some plastics affect the valves in the heart.”
Research shows that 20% of freshwater fish at 50 different sites exhibited more feminine traits, and the offspring of these fish tended to be more vulnerable to chemical changes, UPI reports.
In addition, Tyler said that medications such as anti-depressants have turned some fish into more sociable creatures, which can be deadly. He said, “Other research has shown that many other chemicals that are discharged through sewage treatment works can affect fish, including antidepressant drugs that reduce the natural shyness of some fish species, including the way they react to predators.”
The effects of chemicals on fish and their gender has been a subject of interest among scientists for years. In 2010, The Potomac Conservancy in Washington, D.C. asked for more studies when over 80% of male bass fish in the Potomac River started showing female characteristics, like eggs in their testes.
Vicki Blazer, a fish biologist with the US geological survey, said they are working on identifying which chemicals are behind these changes. “We have not been able to identify one particular chemical or one particular source. We are still trying to get a handle on what chemicals are important.”
