AN EXAMINATION OF MANGANESE CONTAMINATION IN VIRGINIA PRIVATE DRINKING WATER SYSTEMS

Manganese, a naturally occurring element, can leach into groundwater and pose significant health risks, particularly to neurological development and cognitive function. Although regulated as a secondary (nuisance) maximum contaminant limit (SMCL) of 0.05 mg/L (50 ppb) for public water supplies under the EPA's Contaminant Candidate List, private water systems (e.g., wells and springs) remain unregulated, leaving homeowners responsible for testing and maintenance. This study analyzed 24,117 private drinking water samples collected across all Virginia counties from 2008 to 2023 through the Virginia Household Water Quality Program (VAHWQP). The samples, representing diverse geological formations, were subjected to spatial and statistical analyses, revealing significant clusters of elevated manganese concentrations—greater than the SMCL of 0.05 mg/L (50 ppb) —in political units such as Wise, Alleghany, Loudoun, Virginia Beach, and Staunton. Our analysis revealed that elevated manganese levels are linked to manganese-rich mineral deposits, specific soil types, and wetlands. Rural communities and renters are particularly vulnerable to manganese and other contaminants due to a reliance on private water sources combined with information and policy gaps on private drinking water quality. In fact, despite 20% of Virginians depending on private sources, roughly 80% have never tested the water or only tested it once. This highlights the urgent need for enhanced monitoring, public education, and regulatory strategies to address manganese and other contaminants in private drinking water supplies.