Radium levels rise in Wisconsin tap water

In 2014, the village of Sussex in southeast Wisconsin made a dismaying discovery. The radioactive element radium, a contaminant that occurs naturally in bedrock throughout the region, had seeped into two of its seven water wells.

It was not exactly a surprise. Radium has long been a problem in drinking water for dozens of Wisconsin communities from Green Bay to the Illinois border.

The city of Waukesha has proposed replacing its radium-tainted groundwater with Lake Michigan water. If approved, the controversial plan would mark the first test of a provision in a 2008 international compact that allows Great Lakes water diversions only when a county — such as Waukesha County — straddles the basin that feeds water into the Great Lakes...