"Chicago's first round of testing for a toxic metal called hexavalent chromium found that levels in local drinking water are more than 11 times higher than a health standard California adopted last month.
But it could take years before anything is done about chromium contamination in Chicago and scores of other cities, in part because industrial polluters and municipal water utilities are lobbying to block or delay the Obama administration's move toward national regulations.
The discovery of hexavalent chromium in drinking water is renewing a debate about dozens of unregulated substances that are showing up in water supplies nationwide. Potential health threats from many of the industrial chemicals, pharmaceutical drugs and herbicides still are being studied, but researchers say there is strong evidence that years of exposure to chromium-contaminated water can cause stomach cancer.
Test results obtained by the Tribune show that treated Lake Michigan water pumped to 7 million people in Chicago and its suburbs contains up to 0.23 parts per billion of the toxic metal, well above an amount that researchers say could increase the long-term risk of cancer."