Pacific Swell

Southern California environment news and trends

Four fast facts about chromium's slow soak into our waters

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Julia Roberts may have put the story of Hinckley and hexavalent chromium on the map, but the chemical's doing its own work to stay there. The Environmental Working Group found chromium 6 in 89 percent of water samples they commissioned across the country. EWG is, essentially, the NRDC's client in the case filed Tuesday, on which I reported. They've made a point of highlighting this problem as a national one. It's not just the Inland Empire anymore. 

In some ways that just means more people having more trouble understanding the complexities of the chemical's hazard. About 8 months after California's Office of Environmental Health and Hazard Assessment identified a public health goal of two hundredths of a part per billion, EWG released a report emphasizing that twenty-five cities nationally exceed California's proposed "standard." That'a a little misleading; to put it in context, here's four key ways people get confused around drinking water contaminants in general and chromium in particular. 

A public health goal is very different from a maximum contaminant level.

OEHHA sets a public health goal; the Department of Public Health sets the maximum contamination limit. The goal is not enforceable. It's also a part of the analysis for the MCL. In literature where EWG refers to California's standard, it's clear they're intending to mean the public health goal, because they're referring to OEHHA's number, .02 ppb. This matters because, just as with many other drinking water contaminants, the goal differs from the maximum contamination limit, the MCL. The MCL takes into account the best available treatment technology and cost too. The federal government does the same thing for water contaminants, they just use a slightly different alphabet soup.

Current state and federal rules limit total chromium, which includes more than one kind. 

California does have a limit for chromium 6, but indirectly. The state's limit for total chromium is 50 parts per billion. The federal limit is twice that, 100 parts per billion. Environmental activists who want to see a limit for chromium 6 in water say "that's thousands of times what California says is safe!" But that's an exaggeration, and a distortion. Total chromium includes chromium 3: EPA's explanation for why there's one total chromium limit is that chromium 6 and chromium 3 can convert back and forth in water, and back and forth in people.(More on that in a sec.) 

And then with yesterday's story: Glendale's Peter Kavounas told me that the city's water is treated and blended to a level 10 times smaller than the state's standard. He's talking about total chromium, not chromium 6 directly. He also made a good point. He said when people ask him whether the water is safe, he has trouble answering. He knows he can say that water is treated to a standard set by a regulator for public safety. He drinks the same water. But safe is something he'd prefer to leave to medically-trained scientists. 

Chromium 6 acts very differently from chromium 3. Both chromiums are natural. On top of that, some chromium 6 dumped into groundwater came from human activity. 

You can find chromium 3 in vegetables, fruits, and grains. You can find natural chromium 6 in the Coachella Valley Water District, where natural deposits of the chemical erode and reveal themselves. You can find human-activity-deposited chromium 6 in places like Hinkley, the San Fernando Valley, the San Gabriel Valley, and the inland empire. 

The cancer risk for breathing chromium 6 was established longer ago than that for ingesting chromium (like through drinking water). 

More than two decades ago scientists figured out that chromium 6 is a carcinogen when you breathe it. It's only recently that studies have accelerated about how much water you have to drink to get cancer from chromium 6 in it. The National Toxicology Program established that water-borne chromium 6 is a carcinogen in 2009…and after California's legislators and health regulators nominated it for testing. The wrinkle is that the link to cancer was established by testing on lab rats. Extrapolating the data to people "remains controversial." Marla Cone, a former LA Times reporter who runs Environmental HealthNews now, tells you why: 

When setting a standard, scientists use high animal doses to extrapolate to a lower dose designed to protect people from a 70-year lifetime of exposure. Water standards are usually designed to keep the cancer risk to one case in every million or 100,000 people.

The stakes are high; everyone I talk to in government and water management says they want to do it right this time, because there's been so much uncertainty in the past. 

We don't exactly know what the impact of lobbying is on this process. 

We do know that large companies like Lockheed Martin regularly lobby against chromium legislation. And a study about corporate influence on public health that takes California and chromium 6 as an example suggests that a failure to investigate conflicts of interest compromised California's process on at least one big occasion. But going slow isn't necessarily evidence that someone's trying to bury tougher chromium 6 rules.

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