Monday, June 23, 2008 : 9:10 a.m.

Arsenic Distribution and Occurrence In Ground Water from Coastal Plain Aquifers In Maryland

David D. Drummond, Maryland Geological Survey

            Arsenic concentrations exceed the US EPA maximum contaminant level (10 ug/L) in ground water from two coastal plain aquifers in some areas of eastern Maryland. A study is being conducted to determine the distribution of dissolved arsenic in the Aquia and Piney Point/Nanjemoy aquifers, and to estimate the reasons for spatial and depth distribution of ground water with elevated arsenic concentrations. About 250 wells were sampled for arsenic and other constituents to establish geochemical factors associated with the occurrence of elevated arsenic concentrations. About 3000 additional arsenic analyses were obtained from county health departments to supplement data collected as part of this study. These additional analyses helped refine the distribution patterns of dissolved arsenic.

            The distribution of dissolved arsenic and the age of water in the Aquia and Piney Point/Nanjemoy aquifers suggest that arsenic is derived from a natural source within the aquifers, rather than anthropomorphic contamination. Furthermore, no arsenic-bearing minerals are present in these aquifers in sufficient quantities to provide a likely source of dissolved arsenic in elevated concentrations. Possible geologic and geochemical factors affecting dissolved arsenic concentrations in ground water are discussed.

David D. Drummond, Maryland Geological Survey David D. Drummond received his Bachelor of Arts Degree in Geochemistry from the University of Colorado at Boulder in 1977, and his Master of Science Degree in Geology from the George Washington University in 1987. He has worked at the Maryland Geological Survey since 1978 in the Hydrogeology Program. His research includes hydrostratigraphy, ground-water flow and contamination, and water-supply evaluation of the Coastal Plain aquifers in Maryland. Mr. Drummond has developed digital computer models to simulate ground-water flow, solute transport, and particle tracking, and has used a GIS extensively to analyze hydrogeologic data.


[ Manuscript ] Manuscript

2008 NGWA Conference on Eastern Regional Ground Water Issues