The Wonewoc and Tunnel City: A Potential Natural Source of Groundwater Contamination in Western & Central Wisconsin

Preliminary data suggests that the rocks of the Wonewoc Formation and the overlying Tunnel City Group are a natural source for groundwater contamination across west and central Wisconsin, contributing high levels of aluminum, arsenic, cadmium, chromium, cobalt, copper, iron, lead, manganese, nickel, vanadium, and zinc that are above the advised levels for consumption, and additionally, lowering groundwater pH. In the proposed research, we will compile geochemical and mineralogical data for the Wonewoc-Tunnel City contact interval that will provide a baseline for future research and regulations focused on mitigating this potential regional health hazard. In regions where elements that are potential health risks are identified, we will use geophysical logs from wells to reconstruct relationships between the Wonewoc-Tunnel City contact interval and the water table, groundwater electrical conductivity, and groundwater flow to determine locations of possible groundwater contamination for sampling in subsequent studies.