Flushed away

Flushed away

June 3, 2009

You can tell a lot about a city’s health and habits by studying the water around it. Scientists are pinpointing in our waste water the toxic substances contained in household detergents and the drugs we excrete in our urine, then studying how the chemicals affect aquatic fauna — and perhaps even humans.

“There are many prescription and non-prescription drugs primarily coming out of municipal waste-water treatment plants, and those are distributed in streams, rivers and lakes,” says Chris Metcalfe, a biologist at the Worsfold Water Quality Centre at Trent University in Peterborough, Ont. “Some can be quite persistent.”

Advanced water-treatment technologies usually screen out harmful substances, but not every municipality can afford them. And trace amounts still elude even the best plants, says Metcalfe. So he and his colleagues are now looking at whether these chemicals are contaminating drinking-water supplies. For if they are, there is concern about the long-term impact on the developing systems of children from exposure to chemical combinations, such as heart medication, antidepressants and birth control pills.