Saturday, September 24, 2011

Gender-bent fish found downstream of pharmaceutical plants

High levels of intersex fish are found in wild populations that live downstream to a pharmaceutical production plant, showing for the first time that the two are linked.

A French study finds that more than three-quarters of wild gudgeon fish examined had a mix of male and female traits in their sex organs if they lived directly downstream to a plant that manufactures pharmaceutical drugs.

Exposure to the chemical mix discharged from the nearby drug plant may contribute to the abnormalities, the researchers report in the journal Environment International. The study is important because it is the first to link discharge from a drug manufacturing plant – rather than a sewage treatment plant – with physical and chemical changes in fish living downstream.

The researchers found that up to 80 percent of the fish they tested were intersex – that is, the fish had both male and female characteristics in their ovaries or testis. Intersex indicates endocrine disruption in fish that can foreshadow larger effects on fish populations because of reductions in breeding abilities.

Pharmaceuticals can enter the environment through sewage treatment plants after people excrete them or flush unwanted drugs down the toilet. They can also directly enter waterways via discharge into rivers and streams by drug manufacturing plants. Which source contributes more is not known. more