Enforcing limits on chromium-6, a naturally occurring toxic chemical found in Oahu’s drinking water, is a priority on the environmental health agenda for the state Legislature this session.
Senate Health Committee Chairman Josh Green is pushing to establish a 0.06 parts per billion limit of the chemical in tap water. Chromium-6 was highlighted in the 2000 film "Erin Brockovich" that led to a $333 million legal settlement in Hinkley, Calif.
The latest Honolulu Board of Water Supply sampling between January and July 2011 found chromium-6, a known carcinogen in animals, ranging from 0.2 parts per billion in Mililani to 9.8 parts per billion in Kunia.
The U.S. Environmental Protection Agency has not yet set a legal limit for the toxic chemical, also known as hexavalent chromium, and water utilities aren’t required to test for it.
"The fact that we don’t have a standard on chromium-6 is a problem," Green said. "It can occur naturally, but also through filtration and just clean water processes, we can make sure we don’t reach a threshold that’s unsafe. Chromium-6 is a heavy metal toxin and it’s been shown to cause cancers in lab animal studies, so I think it’s something that merits regulation for the safety of our children."
Green’s proposal would require the water board to establish a reporting and public alert system on water quality.
The issue was in local headlines a year ago when a study by Washington, D.C.-based nonprofit Environmental Working Group found chromium-6 present in higher-than-recommended levels in a single sampling of the city’s water supply.
The sample at 2 parts per billion was the second-highest level found among 35 samples nationwide. The highest was 12.9 ppb in Norman, Okla. California has a revised public health goal of 0.02 ppb — from 0.06 — for chromium-6 in drinking water.
The state Health Department said at the time that Oahu’s drinking water was safe despite the presence of tiny amounts of the chemical. The department said it would not comment on the legislative proposal until the measure is formally introduced this session.
The EPA sets a standard of 100 parts per billion or less for all varieties combined of chromium in drinking water, including chromium-3, an essential nutrient. There are several different types of chromium, and the EPA has said chromium-6 is likely to be carcinogenic for humans when consumed in drinking water.
The WATER Board hasn’t tested for chromium-6 since July, said spokesman Kurt Tsue.
"We’ve also been waiting on guidance from the EPA on this topic," he said. "There is no set standard for chromium-6 specifically."
Costs of further filtration and testing hasn’t been determined, he said.
"I don’t think (the water is) unsafe, but I think it’s important that we take a look at all potential toxins that can affect our health," Green said. "This is a priority."
The contaminant commonly is emitted from steel and pulp mills as well as metal-plating and leather-tanning facilities. It also pollutes water through eroding soil and rock.
"There’s some areas that just have spotty problems … but in other areas you kind of see elevated chromium around the state consistently that is a particlar concern," said Renee Sharp, director of the California office and senior scientist at Environmental Working Group. "Hawaii is one of those states where you have quite a bit of the state having elevated chromium levels. It’s more widespread."
The source comes from Hawaii’s geology "so it’s not that you’ve got just a few areas with contamination from industrial sites, but naturally higher levels of chromium in the rocks and soil and geological formation that leach into the ground water," she said. "We think there should be a national standard. In the meantime, we do think it’s very wise for states to set their own standards."
