Chicago to test drinking water for chromium 6

City officials say Chicago will begin routine testing of its tap water for a form of the heavy metal chromium linked in recent studies to stomach cancer.

Officials announced the additional testing Tuesday, shortly after the U.S. Environmental Protection Agency released a memo to the nation's public water systems urging them to take a closer look at the presence of hexavalent chromium in public water supplies.

Hexavalent chromium is also known as chromium-6.

The Chicago Tribune reports that an independent laboratory hired by a nonprofit research and advocacy organization, recently found chromium-6 in tap water from 31 cities. The amount in Lake Michigan water pumped to Chicago and dozens of suburbs was 0.18 parts per billion, nine times higher than a California safety limit adopted this month.