Barium is a metal found in rocks and soil. It enters water through mining and industrial processes. High levels can cause cardiovascular problems and high blood pressure.

Barium naturally occurs in many minerals but can concentrate in water due to mining, oil drilling, and industrial discharge. The EPA limits barium in drinking water to 2 mg/L, measured using atomic absorption spectroscopy. While essential in small amounts, excessive barium intake may lead to health issues. Water treatment plants can remove barium through ion exchange or reverse osmosis. Home water softeners may also reduce barium levels in well water.