Thermo Fisher Scientific Collaborates with US EPA
Hexavalent Chromium, Cr(VI), is a toxic compound regulated by the EPA for certain wastewaters. Scientists from Thermo Fisher Scientific have been participating in a collaborative project with the EPA Office of Ground Water and Drinking Water in Cincinnati to improve the holding time and sensitivity of US EPA Method 218.6 per the company’s Application Update 144. The new method for processed drinking water is 218.7 as per Application Update 179, which demonstrates 1 part per trillion (ppt) detection of chromate using 2 mm anion-exchange columns (Thermo Scientific Dionex IonPac AS7) using one of the company’s Reagent-Free™ Ion Chromatography systems.
The need for a high-sensitivity method was triggered after review of the US EPA Toxicological Review of Hexavalent Chromium, when some states and localities began to lower the actionable level of chromate in drinking water. The sensitivity as shown in AU179 permits a method detection limit (MDL) for chromate of 0.001 μg/L, resulting in a quantitation limit of 0.003 μg/L. This sensitivity is more than sufficient for analysis at newly proposed levels, such as that proposed by the Office of Environmental Health Hazard Assessment (OEHHA) at the California EPA, which recently issued a new public health goal (PHG) lowering the actionable level of chromate in drinking water to 0.02 μg/L (ppb).