The synthetic hormones used in birth control pills and hormone replacement therapy ultimately end up in our sewage systems. Sewage goes to sewage treatment plants. Treated water then goes back into the environment.
But the water treatment doesn't filter out the estrogens.
Which begs the question, what about the fish?
According to the Canadian Freshwater Institute Fisheries and Oceans, it doesn't look good. Their report Effects of a Synthetic Estrogen on Aquatic Populations: a Whole Ecosystem Study suggests that this is an environmental concern worth watching.
This is from their executive summary:
Municipal wastewater treatment plants (MWTP) discharge numerous contaminants into aquatic systems, and some of these chemicals are known or believed to act like hormones and interfere with the growth, reproduction and development of aquatic organisms. It is becoming increasingly apparent that male fish exposed to these effluents are becoming feminized due to the presence of natural and synthetic estrogens in the water. The potent synthetic estrogens excreted by women taking hormone replacement therapy or birth control pills are not completely broken down in the sewage treatment process and are discharged into waterways. The male fish exposed to these estrogens produce egg proteins, have smaller gonads and, in the more severe cases, develop eggs...
During the summer of 2001, the synthetic estrogen used in birth control pills, ethynylestradiol, was added continuously to one lake to maintain low and environmentally-relevant concentrations in the water. Laboratory and field studies had previously demonstrated that this estrogen does not persist in the water, and can be degraded by bacteria naturally present in the sediments of the lake. The additions were done from the end of May until the end of October, and mean concentrations of the estrogen were 6.1 ng/L in the surface waters of the lake. We monitored the lake for responses of the individual fish (lake trout, sucker and minnows) and their populations, as well as changes in the tadpoles, bacteria, algae, leeches, zooplankton and benthic invertebrates as a result of the estrogen additions.
This study was successful at reproducing some of the impacts seen in fish downstream of MWTPs. Male fish from the estrogen-addition lake produced high concentrations of egg protein precursors, had developmental delays in their gonads and, in one species of minnow, produced eggs. Female fish exposed to the estrogen also showed delays in reproductive development and changes in the amount and timing of the egg protein production. The kidneys and livers were also impacted likely due to the atypical and high production of egg proteins in these fish. In the fall of 2001, we did not see any changes in the sizes of the fish populations, fish growth rates, the numbers of males versus females, and the survival of the offspring. It is likely that population- level responses of long-lived organisms will take longer to appear, and for this reason we are continuing to monitor the fish populations in this lake for 3 years following the estrogen additions.
The short version? We've got some freaky fish out there now.
Which means we need some solutions here. Obviously we will need to alter our water treatment methods. Who knows what else might be geting through. Of course, it will take time and more research to figure out how to do that, so what do we do in the meantime to minimize the environmental impact of our excess artificial estrogen?
There will always be a few people who need their medical hormone treatments for their health, and they should be able to recieve them, but the rest of us have some thinking to do.
Personally, I'm still a fan of Natural Family Planning. No excess hormones. No trash to throw away. (Don't forget the used condoms, sponges, diaphragms, cervical caps, patches, nuva-rings, injection needles, pill packages, etc. have to go somewhere) And, as I have pointed out before, emerging German research indicates that NFP has the same success rates as the pill, when used properly.
But what about people who just don't want to give up their birth control pills? What are they going to do?
Maybe Al Gore could start an estrogen offset program. :)
Hat tip: Alan
Update May 2, 2007: Wondering if I could be the first to use the term "estrogen footprint" I did a Google search and found out that one other person (a commenter on another blog) has thought up the term besides myself and used it online, a mere 3 weeks before I originally composed this post. :) The two of us should get together and write a Wikipedia entry. It's kind of fun to be one of the first ones to use a new term in writing. (Yes, I'm a language nerd.)