Manganese exposure from spring and well waters in the Shenandoah Valley: interplay of aquifer lithology, soil composition, and redox conditions

• Published in: Environmental geochemistry and health 2024-06, Vol.46 (6), p.203, Article 203
• Main Authors: Hinkle, Margaret A. G., Ziegler, Brady, Culbertson, Haley, Goldmann, Christopher, Croy, Marina E., Willis, Noah, Ling, Erin, Reinhart, Benjamin, Lyon, Eva C.
• Format: Article
• Language: English
• Subjects: Aquifers; Chronic exposure; Contamination; Dolostone; Drinking water; Drinking Water - chemistry; Earth and Environmental Science; Engineering; Environment; Environmental Chemistry; Environmental Exposure; Environmental Health; Environmental Monitoring; Environmental Sciences & Ecology; Exposure; Fluorescence; Geochemistry; Groundwater; Groundwater - chemistry; Information systems; Karst; Limestone; Lithology; Manganese; Manganese - analysis; Natural Springs - chemistry; Original Paper; Oxidation-Reduction; Public Health; Public, Environmental & Occupational Health; Sandstone; Sedimentary rocks; Shale; Soil; Soil - chemistry; Soil analysis; Soil contamination; Soil Pollutants - analysis; Soil Pollutants - chemistry; Soil Science & Conservation; Soil types; Soil water; Spectrometry, X-Ray Emission; Spring water; Terrestrial Pollution; Valleys; Water Pollutants, Chemical - analysis; Water quality; Water Resources; Water springs; Water Wells; Well water; Well waters; X ray absorption; X rays; X-ray absorption spectroscopy; X-ray fluorescence
• ISSN: 0269-4042; 1573-2983; 1573-2983
• DOI: 10.1007/s10653-024-01987-4

Manganese (Mn) is of particular concern in groundwater, as low-level chronic exposure to aqueous Mn concentrations in drinking water can result in a variety of health and neurodevelopmental effects. Much of the global population relies on drinking water sourced from karst aquifers. Thus, we seek to assess the relative risk of Mn contamination in karst by investigating the Shenandoah Valley, VA region, as it is underlain by both karst and non-karst aquifers and much of the population relies on water wells and spring water. Water and soil samples were collected throughout the Shenandoah Valley, to supplement pre-existing well water and spring data from the National Water Information System and the Virginia Household Water Quality Program, totaling 1815 wells and 119 springs. Soils were analyzed using X-ray fluorescence and Mn K-Edge X-ray absorption near-edge structure spectroscopy. Factors such as soil type, soil geochemistry, and aquifer lithology were linked with each location to determine if correlations exist with aqueous Mn concentrations. Analyzing the distribution of Mn in drinking water sources suggests that water wells and springs within karst aquifers are preferable with respect to chronic Mn exposure, with  20% of wells exceeding 100 ppb Mn. The geochemistry of associated soils and spatial relationships to various hydrologic and geologic features indicates that water interactions with aquifer lithology and soils contribute to aqueous Mn concentrations. Relationships between aqueous Mn in spring waters and Mn in soils indicate that increasing aqueous Mn is correlated with decreasing soil Mn(IV). These results point to redox conditions exerting a dominant control on Mn in this region.