A fascinating story from PBS, entitled “The Complicated Question of Drugs in the Water“, examines current and potential problems that occur from pharmaceuticals that cannot be completely filtered by our current water treatment plants. You really should read the whole thing, but here is an excerpt:
Scientists think that the main way that the vast majority of pharmaceuticals get into the wastewater is through disposal. The vernacular for many years was to flush unwanted medications down the toilet, and many people still do that despite updated federal guidelines that now advise people to either take unused drugs to a collection site or mix them with kitty litter or coffee grounds and put them in the trash. (The only exception to this are narcotic pain relievers and other hazardous substances.) But even with these guidelines, plenty of medications still end up in sewers, wastewater treatment plants, and, to some degree, back our water supplies.
It’s completely unknown how much of their medications people are still dumping down the drain. And what’s more says Daughton, this disposal can be irregular. You can have very large spike in the concentration of one drug going through wastewater treatment plant followed by a spike in another. As a result, the aquatic community has to deal with an ever-changing pharmaceutical profile.
The good news is that pharmaceuticals are actually really well removed by water treatment plants, Wilson says. For her group’s research on how medications in the water affect zebrafish, they took samples from water both going into and coming out of wastewater treatment plants. Both their research and others’ show that they remove about 95 to 98% of pharmaceuticals.
Despite the efficacy of treatment plants, we also need to account for the fact that people drink water all the time, Wilson says, and that there might be sensitive stages of life when it’s best to minimize exposure, such as the elderly, the very young, and pregnant women.
The real problem is trying to find out what the risk really is, Wilson says.