A long debate over how much hexavalent chromium is too much in drinking water resurfaced last week as state health leaders produced the nation’s first drinking water standard.
Although the carcinogen has shown up in water wells throughout Stanislaus, Merced and San Joaquin counties in higher concentrations than most other places throughout the United States, the new standard suggests Modesto has little to worry about. Some wells in Patterson, Newman and Los Banos, however, have produced samples that would not meet maximum contaminant levels.
Some environmental and clean-water advocates are disappointed with the new standard, saying it’s not strict enough and accusing the California Department of Public Health of caving to pressure from industrial polluters. Some water districts contend the standard of 10 parts per billion of hexavalent chromium will require more water treatment, costing taxpayers.
The average concentration in wells across the country has been estimated by the Environmental Working Group at 0.18 parts per billion, and the California Environmental Protection Agency had suggested the standard here be as low as 0.02 parts per billion.
State public health leaders weighed health factors against costs of removing the heavy metal, waded through more than 18,000 comments from people and interested parties, and settled Tuesday on 10 parts per billion. State public health director Ron Chapman said that “will protect public health” without bankrupting water agencies.
Also known as chromium 6, hexavalent chromium rocketed to public consciousness with the 2000 Julia Roberts film “Erin Brockovich.” Pacific Gas and Electric Co. paid $333 million in damages in a lawsuit, and California legislators in 2001 demanded a new state tap water standard by 2004, making Tuesday’s announcement 10 years late.
The average from 270 tests in Stanislaus County from 1997 through 2008 came to 4.42 parts per billion – far higher than suggested by CalEPA, but less than half the level cited in Tuesday’s new standard. Turlock produced several tests approaching that level, reading from 7 to 9 parts per billion. In San Joaquin County, 375 samples averaged 3.94 parts per billion.
But 161 tests in Merced County averaged 11.07 parts per billion – higher than the new standard – and one well near Los Banos reached an alarming 36 parts per billion. However, some scientists called the data outdated and unreliable.
Hexavalent chromium was a common industrial chemical in years past and also moves naturally from soil to groundwater, much as arsenic and uranium, which also are typical in San Joaquin Valley wells in trace amounts. Too much can cause cancer and organ damage, but no agency has mandated testing levels and, until now, state and federal directives have looked only for total chromium. That includes chromium 3, or trivalent chromium, which is beneficial to human health.
The new standard is expected to take effect July 1.
Acknowledging the 10-year wait for a state standard, Environmental Working Group’s Renee Sharp said, “I’m not sure that the wait was worth it.” She called the standard “better than nothing. But when you know that the standard is not truly protecting the public from cancer and other health impacts, it doesn’t feel like a victory.”
Critics note the standard of 10 parts per billion is 500 times higher than advised by CalEPA.
Clean Water Action program manager Andria Ventura called Tuesday’s announcement disappointing and said poor communities are particularly vulnerable.