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Rhapsody said:
If our water recycling system cannot eliminate the toxins from the medicine that is flushed down the toilet every day.... then how are we to feel safe about drinking the water after flushing our waste down there and having it recycled?

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I was part of the team that helped do some of the groundwork (errrr, sewage work, more like) on this subject. The problem arises when man invents a chemical that mother nature hasn't encountered before. Sewage treatment is really nothing more than bacterial treatment. Little critters have a go at what we flush, and they generally have a hell of a time, extracting all sorts of nutrients/energy from the waste. Occasionally, though, there just doesn't happen to be a critter capable of breaking down a particular chemical......and it comes out the effluent end of a sewage treatment plant (STP) unchanged.

One such chemical is the synthetic estrogen in birth control pills. Natural estrogen has a half-life in a woman's body of around 20 seconds. The only way you'd manage natural estrogen in a pill form would be to take some twice a minute.....hardly practical. So, the chemists figured out that they could create an almost-estrogen molecule, that the body couldn't readily destroy, and the once-a-day birth control pill was created. The problem is that bacteria can't break down this form of estrogen, either, and it flows out into whatever body of water the sewage is released into. There are many such chemicals, which cannot be broken down in STPs. Caffeine is one.

Once this problem was recognized, we also developed ways of managing the risks. For drinking water, activated carbon filters take care of anything on the intake side of the system. Unfortunately, few sewage treatment plants are equipped with similar filters, to treat the effluent we produce.

In Canada, all expired meds can be returned to any pharmacy for disposal. Now, you might come across the odd pharmacist ignorant of that policy, but all pharmacies are supposed to properly dispose of any expired meds submitted to them.

If you're worried about your own drinking water, use a Brita filter system, or similar product. Yes, they really do work.

Lar
Environmental Toxicologist, and random geek.