Only Half of Drugs Are Removed from Sewage, Report Says
January 6, 2014- A new study reveals that treatment plants remove only about half of prescription drugs and other newly emerging contaminants in sewage.
The International Joint Commission, a consortium of officials from the U.S. and Canada who study the Great Lakes, found that six chemicals were detected frequently and had a low rate of removal in treated effluent: an herbicide, an anti-seizure drug, two antibiotic drugs, an antibacterial drug and an anti-inflammatory drug.
Caffeine, acetaminophen and estriol (a natural estrogen) were also frequently detected in sewage but had high removal rates, the study showed.
“The compounds show up in low levels – parts per billion or parts per trillion – but aquatic life and humans aren’t exposed to just one at a time, but a whole mix,” said Antonette Arvai, physical scientist at the International Joint Commission and the lead author of the study. “We need to find which of these chemicals might hurt us.”
Even when ingested at low levels, antibiotics can promote resistance, scientists said.
More than 1,400 wastewater treatment plants in the U.S. and Canada discharge 4.8 billion gallons of treated effluent into the Great Lakes basin every day. The scientists reviewed 10 years of data from wastewater treatment plants globally to see how well they removed 42 compounds that are increasingly showing up in the Great Lakes.
The wastewater plants had a low removal rate (less than 25 percent chance of removing 75 percent or more) for 11 of the 42 chemicals.
Triclosan, an antibacterial and antifungal compound found in soaps, toothpastes and other products, has proven toxic to algae and can act as a hormone disruptor in fish. Triclosan was found frequently, the report showed, and plants had “medium removal efficiency.”
The impact of most of these “chemicals of emerging concern” on the health of people and aquatic life remains unclear. But the commission report concludes that better water treatment is needed.
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