Monday, December 20, 2010
Ann Arbor prides itself in the quality of its drinking water. I remember learning all about our state-of-the-art ozone purification system on a middle school trip to the water treatment plant. Unfortunately, today we are getting reports from the Environmental Working Group that show that Ann Arbor's tap water has 0.21 ppb chromium (VI). That's well over EWG's proposed safe exposure level of 0.06 ppb. Chromium (VI), chromium six, or hexavalent chromium, is the carcinogen Erin Brockovich was fighting against in that movie that won those awards. It is highly toxic in small concentrations and is the cousin of the more benign chromium (III). The EPA only regulates total chromium in drinking water and does not differentiate between these two oxidation states. The maximum allowable level of total chromium in drinking water is 100 ppb; this exposure level is set to prevent dermatitis.
It will be interesting to see how this all plays out. EWG tested tap water in 35 U.S. cities and found some chromium (VI) in all but 4 samples. Being able to drink tap water is something we really take for granted, and it is a luxury with which I do not wish to part. Then again, I really don't know enough about the long term impacts of chronic chromium (VI) exposure at a 0.21 ppb concentration to be able to judge my risk.
Image via Environmental Working Group
Posted by Ben Connor Barrie at 3:40 PM