Hexavalent Chromium (Cr(VI)) in WI Groundwater: Identifying Factors Controlling the Natural Concentration and Geochemical Cycling in a Diverse Set of Aquifers

Background/Need: The level of concern about hexavalent chromium (Cr (VI)) contamination in groundwater was heightened due, in-part, to a highly publicized report by the Environmental Working Group (www.ewg.org/chromium6-in-tap-water) in 2010, which documented the widespread occurrence of Cr (VI), a known carcinogen, in drinking water across the nation and in WI. Since there are almost one million private wells in WI and many public drinking water utilities have groundwater sources, it is critical to more fully understand naturally occurring Cr (VI) concentrations and sources. We hypothesized that the Cr (VI) present in groundwater is naturally occurring and proposed to identify factors controlling natural concentrations and geochemical cycling in WI aquifers than contain high levels of mineralization.
Objectives: The goal of this project is to characterize aquifers material of WI as to their natural background concentrations and identify factors associated with release rates of total chromium (Cr) and hexavalent (Cr(VI)) chromium into groundwater.