Chrome-6

Known by many names – Hexavalent Chromium, Chromium-6, Chromium-6+, Chrome-6, Cr-6, Chrome VI, and Hex Chrome this compound has been receiving some renewed press lately. The EPA has recently issued a new sampling and laboratory analysis guidance for public water agencies and water purveyors. There have also been a few new studies published suggesting that Cr-6 could pose health concerns if consumed over long periods of time. Nobody can forget the stir that Erin Brockovich generated in the 1990s and she’s back in the news and the public spotlight again.

The EPA guidance documents can be found here:

EPA on Cr-6

The California Department of Public Health (CDPH)
information on Cr-6 can be found here:

CDPH on Cr-6

Generally speaking, the new EPA Method 200.8 is capable of reporting total Cr concentrations as low as 0.2 µg/L and Cr-6 concentrations as low as 0.02 µg/L.

It should be noted that these concentrations are simply the lower limit of what the laboratory equipment and procedures can reliably report. These are not the limits at which the water purveyors would need to report to their customers (Known as “Notification Level”), or the concentrations at which remediation needs to be performed (Known as “Maximum Contaminant Levels”). There currently is no Notification Level in California for Cr-6 and the Maximum Contaminant Level (MCL) is currently set at 50 µg/L in California and 100 µg/L nationally.

The California Office of Environmental Health and Hazard Assessment (OEHHA) has published a draft Public Health Goal (PHG) for Cr-6 of 0.06 µg/L and the public comment period closed earlier this month (February 15, 2011). I would expect the PHG to be heavily contested because this concentration is arguably lower than naturally occurring or “Background” concentrations in many areas.

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