Manganese Contamination (IMAGE) University of California - Riverside Caption UCR researchers have shown that the highest concentrations of manganese (Mn), which can be harmful to human health, are found at shallower depths than Arsenic (As) in underground drinking water wells. The study suggests that these contaminants should be evaluated separately to ensure the water is fit for consumption. Credit UC Riverside Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.