Runoff and Intersex Fish in the Potomac

Source: Washington Post

The Potomac Conservancy reports that runoff is causing the intersex fish problem.

The report says it appears that chemicals -- it's still not certain which ones -- in the water are interfering with the hormones that guide development in the fish. It said that potential causes include animal hormones from manure washing off farm fields in the rain and human hormones and pharmaceuticals that are flushed out with treated sewage.

It seems likely, the report said, that the cause is not a single chemical but a mixture whose components might be different around the river. Pesticides might dominate in rural areas, for instance, and human hormones downstream of a sewage plant.

Hedrick Belin, the conservancy's president, said that the best solution to the problem was to try to keep these chemicals out of the water in the first place. That, he said, could entail increased testing to figure out which chemicals have hormone-mimicking properties or installing measures to keep animal waste from washing downstream.

You can read the full report for 2009 at the Potomac Conservancy's website.

Sources of Endocrine Disruptors / Source: Potomac Conservancy

The Potomac Conservancy says that they do not know what effect of these pollutants have on human health. I am not sure how closely the effects on humans have been studied; if anyone knows, I would be happy to find out. In the meantime, I think it is better to err on the safe side and reduce the flow of chemicals that disrupt hormones into runoff. Working to reduce those may have the happy side effect of reducing the introduction of other harmful pollutants into the Chesapeake watershed as well.