2026 MN Ground Water Association Fall Conference
Tuesday, November 17th
American Swedish Institute
Speakers listed in alphabetical order:
Madeline Gotkowitz, PhD – Wisconsin DNR
Bio: Madeline Gotkowitz, PhD, is a hydrogeologist in the Wisconsin Department of Natural Resources’ Water Use Section. She recently returned to Wisconsin following four years serving as Research Division Chief at the Montana Bureau of Mines and Geology, where she led the Bureau’s scientific staff in investigations of Montana’s geologic, mineral, and water resources. Madeline is no stranger to the Upper Midwest, with over 25 years’ experience in environmental consulting and at the Wisconsin Geological and Natural History Survey/University of Wisconsin-Extension. Her professional interests span physical and chemical hydrogeology, with publications addressing groundwater flooding, flow across aquitards, regional groundwater flow models, and subsurface fate and transport of arsenic, radium, nitrate, and pathogens.
Abstract: Almost everything, everywhere, over time: pumping and other factors affecting fate and transport of radium in groundwater systems
Radium (Ra) is a naturally occurring radioactive contaminant present at levels of concern for human health in many groundwater systems. In the Midwestern Cambrian-Ordovician aquifer system, geologic sources of Ra include Ra-bearing aquifer solids, such as oxide rinds on silicate minerals; shales or other fine-grained strata enriched in parent elements uranium (U) and thorium (Th); and deep saline brines. Once in groundwater, Ra mobility is affected by sorption and precipitation reactions, which depend in part on local geochemical conditions (e.g. pH, redox, total dissolved solids). Because that’s just too few variables, local and regional groundwater flow fields affect the advective transport of Ra to individual wells. In southeastern Wisconsin, radium concentrations in many municipal wells have increased rapidly in the past decade, while other communities have seen decreases in recent years. Our modeling studies suggest that diffusive transport leads to elevated background levels, while advection of Ra-enriched groundwater through confining units may lead to a rapid Ra increase in some well-fields. This talk will share these research results and assess potential strategies for controlling Ra in wells.
You must be logged in to post a comment.