If you are a human or any other animal with a backbone, your body makes estrogen. And every day, you send some portion down the toilet to your local sewage treatment plant or septic system. Treated or not, these waste streams ultimately flow into nearby groundwater, rivers, lakes, and coastal waters that often supply the water we drink and the fish we eat.
Estrogens are a family of hormones that are essential for growth and development, and, notably, for determining whether you are a female or a male. Exposure to even small amounts of “extra” estrogen can have profoundly negative health effects, giving rise to male fish with female sex organs, for example.
In 2001, to test just how potent estrogens could be, researchers at Fisheries and Oceans Canada and the United States Environmental Protection Agency began an experiment. They added a synthetic estrogen commonly found in birth control pills to a pristine lake in Ontario at levels typical of those detected in treated sewage. They found that within two years, the lake’s entire population of fathead minnows had collapsed because they were unable to reproduce.
My own research aims to characterize the amounts, variety, and ultimate fate of estrogens discharged with sewage into Massachusetts Bay. Until now, scientists have primarily focused on a single form of estrogen. However, we are looking for a wide array, including chemical forms that have escaped notice in the past, and we are looking for them at very low concentrations. Fortunately, recent advances in detector technology have given us the ability to pick out estrogens from the muddle of millions of other compounds in seawater.