Limit urged for cancer-causing chromium in California drinking water State public health officials Thursday proposed the nation's first drinking-water standard for the carcinogen hexavalent chromium, at a level that elicited sighs of relief from municipal water managers and criticism from environmentalists. At 10 parts per billion, the standard is 500 times greater than the non-enforceable public health goal set two years ago by the state Environmental Protection Agency. The Department of Public Health described the proposed limit as a balance of public health, cost and treatment technology, but the agency acknowledged that economics were a key consideration. Mark Starr, deputy director of the Center for Environmental Health, said the state's aim was to determine the lowest possible limit for the toxic heavy metal "given the technology available and the cost in order to protect public health." Environmentalists said the 10 parts per billion standard - the equivalent of about 10 drops in an Olympic-sized pool - was far too high. "Five hundred times higher than safe levels is not protective of public health," said Avinash Kar, an attorney with the Natural Resources Defense Council, which sued the state to issue the long-delayed standard. Los Angeles, Burbank and Glendale already treat San Fernando Valley groundwater supplies contaminated by aerospace manufacturing to reduce hexavalent chromium levels to 5 parts per billion. That means the proposed new standard would not require them to adopt more intensive - and expensive - methods. "We're happy and pleasantly surprised," said Ramon Abueg, a chief assistant general manager for Glendale Water and Power, which is treating about 15% of its water supply for the pollutant, also known as chromium 6. "We took the most conservative approach until a standard could be set," he said. But Abueg added that the city, which has a sophisticated treatment system in place, would continue to adhere to its more stringent practice. Chromium 6 occurs naturally but is also an industrial contaminant that gained a high profile after the 2000 movie "Erin Brockovich" related how the desert town of Hinkley's water supply was fouled by mid-century releases from a nearby utility operation. The chemical has been found in 51 of California's 58 counties, including Los Angeles, Riverside and San Bernardino, according to the Department of Public Health. State officials said about 128 water systems would be required to treat their supplies under the new standard, at a total annual cost of $156 million. Current state and federal standards do not distinguish between hexavalent chromium and trivalent chromium, an essential nutrient found naturally in foods. Instead, they combine the harmful and benign forms into a limit on total chromium, which the state puts at 50 parts per billion and the federal government at 100 parts per billion. Although Los Angeles has been treating valley groundwater supplies and blending them with imported water to reduce chromium 6 levels to a lower level than the standard would require, Pankaj Parekh of the Department of Water and Power said the new standard was reasonable in light of scientific disagreement over what levels of the contaminant are harmful. "What they've come out with soon might be a little conservative," he said, adding that the city wants to expand treatment of polluted groundwater to increase local water supplies. Bill Mace, an assistant general manager at Burbank Water and Power, said his utility probably would consider adopting the less stringent standard proposed Thursday. "If we went to 10 [parts per billion], it would require us to blend less" with expensive treated water, cutting costs, he said.