UW Extension

Digging deep to find the source of radium in water supplies

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Madeline Gotkowitz is studying which rock layers are contributing radium to Dane County’s water supply wells.

“Radium has become a significant issue for municipalities,” said Madeline Gotkowitz, a hydrogeologist with UW-Extension’s Wisconsin’s Geological and Natural History Survey (WGNHS).

Radium was the issue that drove the city of Waukesha to spend years in their efforts to divert water from Lake Michigan under the Great Lakes Compact. Sandstone aquifers in eastern and southern Wisconsin typically have higher than normal levels of this naturally occurring contaminant that can increase the incidence of bone cancer.

Dr. Gotkowitz began a two-year study in August that will try to determine what geologic strata is contributing radium to Dane County water supply wells. Gotkowitz is working with Matt Ginder-Vogel, an assistant professor of civil and environmental engineering with the University of Wisconsin-Madison. Their work is being funded by the University of Wisconsin Water Resources Institute (WRI). They will be testing 22 monitoring wells in the area to assess just where the natural radium is coming from.

In the second year of their study Gotkowitz and Ginder-Vogel will test rock samples from the WGNHS core repository in Mt. Horeb to characterize which rocks, in which areas of the state, are more likely to have radium problems.

Ultimately, the team would like to be able to advise water utilities about what depth and locations they should case their wells to minimize their radium problems.

“If utilities only need to abandon the bottom 100 feet of a municipal well, the well may still provide enough volume of water to meet their needs,” said Gotkowitz.