Toxic Stew and Intersex Fish

Keeping with the Earth Day theme is this story from The Guardian about an unfolding environmental catastrophe right in the nation’s capital. A study by the Potomac Conservancy found that nearly 80% of the male smallmouth bass in the river that flows through Washington DC are also exhibiting female characteristics (i.e. carrying immature eggs within their testes), a condition known as “intersexing”. Scientists studying the fish can’t pinpoint a single cause for the gender confusion, and believe the condition may be the result of exposure to what they call a “stew” of chemicals – everything from hormones to fertilizers to chemicals used to make fabrics fire retardant. These chemicals make their way into the ecosystem as run-off from farms and suburban lawns and via municipal sewage systems. Once in the ecosystem, the chemicals can interfere with an animal’s endocrine system, causing them develop both male and female characteristics or to exhibit other deformities.

And the problem may not be limited to fish – nearly four million people in the Washington DC area get their drinking water from the Potomac, meaning they too are being exposed on some level to this “toxic stew”. To make matters worse, scientists from the US Geological Survey found intersexed fish in a third of 111 rivers sampled across the country, a survey that included some of the nation’s largest waterways, including the Mississippi and Rio Grande rivers.

The President of the Potomac Conservancy is calling for a study on how chemicals affect the endocrine systems of fish as well as for tougher regulations on the dumping of pharmaceutical products.