Hexavalent chromium, also known as Chrome-6, is a form of the element chromium that is suspected to pose a human health risk if ingested. Chrome-6 is often present at very low levels in groundwater due to its occurrence in certain geological formations. Human caused contamination can also occur due to releases from various industrial processes. Chrome-6 has always been regulated as part of the drinking water standard for Total Chromium, but it is now being regulated on its own.
In July 2014 California established a Maximum Contaminant Level (MCL) of 10 ppb for Chrome-6. According to the State, the new MCL will reduce statewide cancer cases by 12 each year and would cost about $155 million annually in water treatment costs.
Anaheim has been monitoring its water supplies for many years for Total Chromium and has rarely detected it. When Chrome-6 first became an issue following the Erin Brokovich movie, all of Anaheim’s wells were tested. Since monitoring first began in 2001, Chrome-6 has been found in most of our active production wells at levels ranging from the laboratory detection level of 0.2 parts per billion to a high of 3.3 ppb. Anaheim's groundwater has average Chrome-6 levels of approximately 0.7 ppb. Data from Orange County suggests that low levels of Chrome-6 are common in this area due to the natural geology and Anaheim’s Chrome-6 levels are similar to those found throughout the County.
Going forward, Anaheim will continue to monitor its water for Chrome-6 and will ensure that all of its sources meet all drinking water standards.