In the past few years, Hexavalent Chromium Cr(VI), a genotoxic carcinogen, has come under increased scrutiny as it is the most toxic form of chromium found in the environment, and requires regulatory monitoring as a primary drinking water contaminant in the U.S. As per regulations, it needs to be monitored in drinking water, groundwater, industrial wastewater, and solid waste extracts.
After review of the U.S. EPA Toxicological Review of Hexavalent Chromium, some states and localities in the United States have begun to lower the actionable level of chromate in drinking water. For example, the Office of Environmental Health Hazard Assessment (OEHHA) at the California EPA has issued a new public health goal (PHG) of chromate in drinking water of 0.02 µg/L (ppb) and plans to make it enforceable. (According to recent information, the OEHHA might be now reconsidering lowering the 0.02 ppb PHG. There have been two public comment periods since 2009, these comments are published on the OEHHA web site at Public Comments.)
By the way, if you haven’t had a chance to check them out, you should look at the EPA’s enhanced monitoring guidance because they provide recommendations on where the systems should collect samples and how often they should be collected, along with analytical methods for laboratory testing. You can read the EPA Guidance for Monitoring Hexavalent Chromium in Drinking Water or listen to this podcast on the subject.
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During this time, we have been at the forefront of method development for new limits, and are really pleased that our participation in the secondary validation of U.S. EPA 218.7 has been completed now for a few months. Our recently published Application Update 179,Sensitive Determination of Hexavalent Chromium in Drinking Water, demonstrates 1 part per trillion (ppt) detection of chromate using Thermo Scientific Dionex Reagent Free Ion Chromatography (RFIC) systems with 2 mm columns. This level of sensitivity is more than sufficient for analysis at newly proposed levels of chromate in drinking water to 0.02 µg/L (ppb) by OEHHA at the California EPA.
Also, in June 2011, The Column featured an article titled, Sensitive Testing of Toxic Hexavalent Chromium in Drinking Water, written by Lipika Basumallick (Staff Chemist), Jeffrey S. Rohrer (Director of Applications Development), and Richard Jack (Market Development Manager). The article describes the method which allows a minimum quantification limit of 0.003 μg/L, which is more than sufficient for the proposed California standard.
Do share with us your hexavalent chromium testing challenges in our comments section below.