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….

Via As wells go deeper, radium levels rise in state tap water @ WisconsinWatch.org