Prescription drugs and other chemicals are contaminating Lake Michigan as far as two miles from the Milwaukee sewage discharges, according to researchers. That’s an unpleasant surprise for those who had theorized that water was diluting the pollutants to non-threatening levels.
With 14 chemicals found at levels of “medium or high ecological risk,” scientists don’t know what effect they are having on fish and other aquatic life. But they are concerned.
“You’re not going to see fish die-offs but subtle changes in how the fish eat and socialize that can have a big impact down the road,” said Dana Kolpin, a research hydrologist for the U.S. Geological Survey. “With behavior changes and endocrine disruption, reproduction and survival problems may not rear their ugly head for generations.”
The chemicals’ ability to travel and remain at relatively high concentrations means that aquatic life is exposed, so there could be “some serious near-shore impacts,” added Rebecca Klaper, an associate professor at the University of Wisconsin-Milwaukee and senior author of the study published in the journal Chemosphere.
Of the 27 chemicals found, the most prevalent were caffeine, metformin (an antidiabetic drug), sulfamethoxazole (antibiotic), and triclosan, an antibacterial and antifungal compound found in soaps and other consumer products. The latter is known to be toxic to algae and can act as a hormone disruptor in fish.
The real problem, though, is the witch’s brew created by the contaminants blending together in the fishery. “It’s going to be hard to ease out which of these compounds may do harm,” Kolpin said.
Klaper added that the Milwaukee Metropolitan Sewerage District does a better job than other plants at removing many compounds. But its facilities are just not equipped to handle the volume.
“For example, we found quite a bit of caffeine in the lake, and they’re removing about 90 percent of the caffeine that comes in for treatment. They can’t remove everything.”
Capturing these pollutants is a challenge not just for Milwaukee’s treatment plants but for those across the country, according to Kevin Shafer, executive director of the Milwaukee Metropolitan Sewerage District.
“At the time wastewater treatment plants were developed, these compounds were just not an issue,” he said.
(This article appeared originally in B.A.S.S. Times.)