What is the source of estrogen in wastewater?

http://www.straightdope.com/columns/read/3277/what-happens-to-hospital-wastewater brings up an issue that has puzzled me about the secondary effects of estrogen in the waste stream. If 12,000,000 women in the US are taking the maximum daily dose pill of 50 micrograms of estrogen, that adds up to 219 kilograms of estrogen. There being just over 16,000 WWTPs, that works out to 13 grams a year per WWTP. Is estrogen that potent, or is there some other source that dwarfs the effects of The Pill in the environment.

Many thanks,
The Waz

Is that 12 million just the number of women taking BC pills? What’s the source of that number? I didn’t see it in the column cited. There are additional reasons to use estrogen.

Perhaps Cecil was talking about estrogenic chemicals, not just estrogen pills taken by humans. http://www.naturodoc.com/library/hormones/estrogen_pollution.htm

It wasn’t in the Straight Dope article, but Web MD’s on the birth control pill.

Additionally (actually subtractionally) not all of the estrogen containing waste is going to WWTPs, leading to a even, theoretically, lower concentration. Estrogen is used in animal feed and is even used as an implant in animals.