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Bacteria May Be Remaking Drugs in Sewage

Wastewater treatment plants not only struggle removing pharmaceuticals, it seems some drugs actually increase after treatment.

When researchers tested wastewater before and after treatment at a Milwaukee-area treatment plant, they found that two drugs—the anti-epileptic carbamazepine and antibiotic ofloxacin—came out at higher concentrations than they went in. The study suggests the microbes that clean our water may also piece some pharmaceuticals back together.

Carbamazepine and ofloxacin on average increased by 80 percent and 120 percent, respectively, during the treatment process. Such drugs, and their metabolites (formed as part of the natural biochemical process of degrading and eliminating the compounds), get into the wastewater by people taking them and excreting them. Flushing drugs accounts for some of the levels too.