Substances not yet added to list of contaminants the city must report
The annual water quality report Chicago recently mailed to residents did not address the pharmaceutical drugs and sex hormones that were discovered in drinking water.
The city is required to alert Chicagoans if the drinking water contains regulated contaminants such as lead, pesticides and harmful bacteria, but pharmaceutical chemicals have not been added to the list.
Tests on treated Lake Michigan water in 2008 revealed small amounts of testosterone and progesterone, a prescription cholesterol-fighting drug (gemfibrozil), ibuprofen, and DEET.
Regulators and researchers are concerned about the effects of long-term exposure to such substances.
"We're just scratching the surface with what's been detected to date," Dana Kolpin, a researcher at the U.S. Geological Survey, told the Chicago Tribune. "And we don't have a clue about what these mixtures can do."