Elevated manganese concentrations in United States groundwater, role of land surface–soil–aquifer connections

Environmental Science & Technology
By: , and 

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Abstract

Chemical data from 43 334 wells were used to examine the role of land surface–soil–aquifer connections in producing elevated manganese concentrations (>300 μg/L) in United States (U.S.) groundwater. Elevated concentrations of manganese and dissolved organic carbon (DOC) in groundwater are associated with shallow, anoxic water tables and soils enriched in organic carbon, suggesting soil-derived DOC supports manganese reduction and mobilization in shallow groundwater. Manganese and DOC concentrations are higher near rivers than farther from rivers, suggesting river-derived DOC also supports manganese mobilization. Anthropogenic nitrogen may also affect manganese concentrations in groundwater. In parts of the northeastern U.S. containing poorly buffered soils, ∼40% of the samples with elevated manganese concentrations have pH values < 6 and elevated concentrations of nitrate relative to samples with pH ≥ 6, suggesting acidic recharge produced by the oxidation of ammonium in fertilizer helps mobilize manganese. An estimated 2.6 million people potentially consume groundwater with elevated manganese concentrations, the highest densities of which occur near rivers and in areas with organic carbon rich soil. Results from this study indicate land surface–soil–aquifer connections play an important role in producing elevated manganese concentrations in groundwater used for human consumption.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Elevated manganese concentrations in United States groundwater, role of land surface–soil–aquifer connections
Series title Environmental Science & Technology
DOI 10.1021/acs.est.8b04055
Volume 53
Issue 1
Year Published 2019
Language English
Publisher ACS
Contributing office(s) WMA - Earth System Processes Division
Description 10 p.
First page 29
Last page 38