Birth control pills being flushed down toilets are creating a "toxic stew" that turns male fish in the Potomac River into an intersex species who carry eggs in their testes. 90% of DC's drinking water comes from the river.
The toxic stew was discovered by scientists from the US Geological Survey, and it comes not just from birth control pills, but a cocktail of household items that you are flushing down your toilet. Scientist Vicki Blazer explained the mixture. From The Guardian:
The chemicals could include birth control pills and other drugs, toiletries especially those with fragrances, products such as tissues treated with antibacterial agents, or goods treated with flame retardants that find their way into waste water. However, Blazer also pointed to runoff from fertilisers and pesticides from agricultural areas.
And according to studies, it's not just the Potomac that is creating mutant fish, they're everywhere:
A report last year by the US geological survey found intersex fish in a third of 111 sites tested around the country. Of the 16 fish species studied, the condition was most common in smallmouth and largemouth bass and among males, although researchers also discovered the occasional female fish with male characteristics. The researchers studied sites along some of America's greatest rivers from the Mississippi to the Rio Grande.
This should be comforting news to anyone who drinks tap water.