Lead and Manganese in Untreated Drinking Water from Aquifers in the Atlantic and Gulf Coastal Plain, Eastern USA

Monday, December 4, 2017: 11:30 a.m.
101 AB (Music City Center)
Jeannie Barlow, PhD , Lower Mississippi-Gulf Water Science Center, U.S. Geological Survey, Jackson, MS
Craig J. Brown, Ph.D. , U.S. Geologic Survey, East Hartford, CT
Bruce Lindsey , Pennsylvania Water Science Center, U.S. Geological Survey, New Cumberland, PA

Concentrations of lead and manganese in 258 untreated drinking-water samples collected in 2013 from aquifers in the Coastal Plain were compared to select factors related to hydrologic position, mineral saturation, and geochemical conditions. Statistical comparisons between the concentrations and the explanatory factors were used to identify the factors most important to the occurrence of lead and manganese in groundwater. Lead and manganese were selected because: 1.) both trace metals and neurotoxins; 2.) both were detected at elevated concentrations in greater than 2 percent of samples collected within the study area. The lead and manganese concentrations were evaluated in terms of hydrologic position, well depth, and geochemical indicators including pH, dissolved oxygen, specific conductance, and select trace metals. Sample results from 258 wells completed in three principal aquifers in the Coastal Plain aquifer systems were included in the analysis. Elevated concentrations of lead were associated with relatively younger, high-oxygen, low-pH waters which occurred closer to recharge zones (relatively shorter flow paths). Elevated concentrations of manganese were associated with relatively older, low-oxygen, low-pH waters which occurred further away from recharge zones (relatively longer flow paths). Based on these associations, dissolved oxygen and pH, both relatively easy to measure in groundwater, can be used to identify locations within aquifers in the Coastal Plain systems that may be more susceptible to elevated manganese and lead concentrations.
Jeannie Barlow, PhD, Lower Mississippi-Gulf Water Science Center, U.S. Geological Survey, Jackson, MS
Research Hydrologist


Craig J. Brown, Ph.D., U.S. Geologic Survey, East Hartford, CT
Craig Brown is a hydrologist with the U.S. Geological Survey. His research interests include aquifer geochemistry and processes associated with the mobilization and transport of trace elements in aquifer systems. He is currently working on studies of transport of anthropogenic and natural contaminants to public supply wells for the National Water-Quality Assessment Program, and the geochemical implications of Aquifer Storage and Recovery.


Bruce Lindsey, Pennsylvania Water Science Center, U.S. Geological Survey, New Cumberland, PA
Hydrologist


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