An evaluation of the distribution and sources of dissolved strontium in the groundwater of eastern Wisconsin, with a focus on Brown and Outagamie counties

Background/Need:
Groundwater in parts of eastern Wisconsin contains dissolved strontium (Sr) levels that exceed lifetime and short-term EPA Health Advisories of 4 mg/L and 25 mg/L, respectively. Hundreds of wells are impacted throughout this region, including an area of anomalously high dissolved Sr in parts of Brown, Outagamie, and Calumet counties, which could potentially lead to health effects such as tooth enamel mottling or strontium rickets. Prior to this project, limited information was known about spatial distribution of dissolved strontium and how this relates to the aquifer chemistry, and very little was known about the source of the dissolved strontium.

Objectives:
This study had two principal objectives. The first objective was to determine the regional and stratigraphic distribution of dissolved strontium (Sr) in the groundwater of eastern Wisconsin, with a focus on Brown and Outagamie counties. The second objective was to evaluate potential sources of Sr in bedrock aquifers present in the region using various petrographic, geochemical, and isotopic methods.