Context for Chemical in Ann Arbor Water
On Monday, Dec. 20, 2010, the Environmental Working Group (EWG) released results of a study it conducted, which sampled water in 35 American cities. The EWG tested the samples for hexavalent chromium, a toxic kind of chromium used in several industrial processes, but also occurring naturally in low levels.
In a phone interview with The Chronicle, Rebecca Sutton – the principal investigator for the EWG study – said the goal of the sampling was not to try to characterize the water supply of any community over any period of time – only one sample was taken in each city. In Ann Arbor, that sample came from a residence.
The group found hexavalent chromium in 31 of the 36 samples collected. In 25 of those samples, the levels of hexavalent chromium were higher than a public health goal that has been proposed by the Office of Environmental Health Hazard Assessment (OEHHA) in California: 0.06 parts per billion (ppb).
Ann Arbor is among the communities that had a sample with a hexavalent chromium level higher than 0.06 ppb. The level in Ann Arbor’s sample was 0.21 ppb – roughly three times the proposed public health goal in California. [For a complete list of cities tested and their levels of hexavalent chromium – also known as chromium-6 – see the EWG report.]
So what’s at risk here? How did Ann Arbor wind up on the EWG’s list to test? And once Ann Arbor was on the list, how did EWG get a water sample to test? [Full Story]