Common pills, plastics making male fish lay eggs: Studies

Plastics, pesticides and even common prescription drugs are releasing synthetic and natural hormones into rivers and streams, which is leading to unintended consequences on wildlife, causing some male fish to become feminised and lay eggs.
 
In a recent report, it was found that one third of small mouth bass were feminised in nine major U.S. river basins, and almost all of the rivers and streams tested in the United States contained some hormonally active chemicals.

And now in a conference, the researchers are focussing on the long-term consequences of hormones and endocrine disruptors in the environment. "It is one of the hottest topics in environmental biology right now. The biological activity of these compounds both in terms of other species and, potentially, ourselves is something that scientists are becoming more and more aware of through research," said Dr. John McLachlan, director of the Tulane/Xavier Center for Bioenvironmental Research, which is hosting the conference.

Now scientists are looking at the proliferation of prescription drugs like antidepressants, contraceptives and other medications that are ending up in wastewater after being taken by people. Most municipal water treatment systems don't have the ability to neutralize pharmaceutical compounds in wastewater so they end up in rivers and streams, said McLachlan. "They all end up in different places in the environment. What do they do to the wildlife that absorb them and, more importantly, what do they do to our water sources?" he says.

A recent study found feminised male fish in almost a third of 111 sampling sites in nine major U.S. river basins and scientists are studying whether endocrine disruptors are responsible.

Tyron Hayes, a leading expert in intersexed amphibians, will be speaking at the conference about his research on the effects of endocrine disruptors on wildlife. The conference also discusses how hormones affect the body and endocrine system and how they may play a role in diseases like breast cancer.

The findings will be discussed in the Tenth International Symposium on Environment and Hormones (E.hormone 2009).