Following the release of a study that found hexavalent chromium (chromium-6) in tap water in 31 of 35 U.S. cities tested, the U.S. Environmental Protection Agency is recommending that all drinking water providers begin enhanced monitoring for chromium-6.
The Eugene Water & Electric Board has been monitoring for total chromium since the early 1980s, and has never detected the metal in the raw water drawn from the McKenzie River, nor has the utility detected chromium in its finished water or in the distribution system.
The utility's sampling threshold for chromium has been set to detect the metal at 10 parts per billion (0.01mg/L), while the EPA's maximum contaminant level for chromium has been set at 100 parts per billion (0.1 mg/L). EWEB will comply with the EPA recommendation and monitor for chromium at the enhanced level of 0.05 parts per billion (0.05 ug/L).
EWEB will begin the enhanced monitoring for chromium starting next week. After the initial samples are taken, EWEB will continue to take samples every quarter. The utility will collect samples of water at its Hayden Bridge intake, at the treatment plant, and from various locations in the distribution system. These samples will be sent a laboratory in California with specialized equipment capable of detecting minute levels of chromium.
Hexavalent chromium is not a regulated contaminant, but the EPA's recommendation are in response to emerging scientific evidence that chromium-6 can pose health concerns if consumed over a long period of time. Although chromium occurs naturally, it is used in manufacturing processes including stainless steel products, treated wood, pulp mills and leather products.
EWEB will continue to support research by the EPA and other government and scientific organizations to provide guidance to water utilities regarding contaminant monitoring. The EPA expects to complete its risk assessment on chromium-6 later this year.
