WRF Report on State of the Science for Hexavalent Chromium

The Water Research Foundation has produced a report evaluating the state of the science for hexavalent chromium, a contaminant that is currently unregulated but has received significant attention in the media over the past year. Their review looked at chromium chemistry in water treatment and distribution, occurrence, health effects, analysis, and work needed. The two oxidation states of chromium (trivalent and hexavalent) behave differently in water in the environment and during water treatment and have much different health impacts. The hexavalent state is the one associated with possible negative health effects, including cancer. The report points out that the health effects from drinking water are based on studies with limited scope or other deficiencies. EPA is completing their evaluation of the health effects as they consider what regulatory action is needed for hexavalent chromium. The full extent of chromium occurrence is not known. Determining occurrence is complicated by the difficulties in measuring low levels of hexavalent chromium with analytical methods commonly used.

The report identifies a number of areas where additional work is needed to fully evaluate and address hexavalent chromium. These include the extent of low level occurrence, analytical method improvements for hexavalent and total chromium, the possible introduction of chromium from treatment chemicals, chromium treatment methods, oxidation of trivalent to hexavalent chromium in the distribution system, and communication strategies for keeping water system customers informed. The report is available at http://bit.ly/wr2Xy0. AWWA will discuss this report and other information on hexavalent chromium in a special complimentary webcast on Wednesday, February 29, 2012, from noon to 1:30 p.m. EST. To register for the free webcast visit the AWWA website.