The leakage of NO3 and pesticide residues from agricultural landscapes to groundwater has important implications for drinking water quality and aquatic ecosystem health.

Nitrates in surface waters of the Little Plover River, a cold, groundwater fed stream located in central Wisconsin, have increased from about 2 mg/L | NO3-N in the 1960s to over 8 mg/L NO3-N by 1997.

The occurrence of arsenic in groundwater in parts of Northeast Wisconsin was first identified in 1987 during a routine feasibility study for a proposed landfill location in the town of Vinland, Winnebago County, and has been an ongoing problem since that discovery.

This project was designed to investigate the extent and source of radium contamination in the Cambro-Ordovician aquifer system of eastern Wisconsin.

The Maquoketa Formation, a dolomitic shale, forms the most important aquitard in eastern Wisconsin, USA, isolating the water-table and Silurian aquifers from the underlying Cambrian-Ordovician aquifer.

Carbonate aquifers form important regional sources of drinking water in eastern and southern Wisconsin. Previous work in Door County suggests that vertical fractures as well as horizontal partings and dissolution zones provide the primary pathways for groundwater flow