title: Can arsenic occurrence rates in bedrock aquifers be predicted?
abstract: A high percentage (31%) of groundwater samples from bedrock aquifers in the greater Augusta area, Maine was found to contain greater than 10 μg L(-1) of arsenic. Elevated arsenic concentrations are associated with bedrock geology, and more frequently observed in samples with high pH, low dissolved oxygen, and low nitrate. These associations were quantitatively compared by statistical analysis. Stepwise logistic regression models using bedrock geology and/or water chemistry parameters are developed and tested with external data sets to explore the feasibility of predicting groundwater arsenic occurrence rates (the percentages of arsenic concentrations higher than 10 μg L(-1)) in bedrock aquifers. Despite the under-prediction of high arsenic occurrence rates, models including groundwater geochemistry parameters predict arsenic occurrence rates better than those with bedrock geology only. Such simple models with very few parameters can be applied to obtain a preliminary arsenic risk assessment in bedrock aquifers at local to intermediate scales at other localities with similar geology.
authors.affiliation: Queens College and Graduate Center, City University of New York, 6530 Kissena Blvd., Flushing, New York 11367, United States.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Yang
authors.forename: Hun Bok
authors.initials: HB
authors.lastname: Jung
authors.forename: Robert G
authors.initials: RG
authors.lastname: Marvinney
authors.forename: Charles W
authors.initials: CW
authors.lastname: Culbertson
authors.forename: Yan
authors.initials: Y
authors.lastname: Zheng
mesh_terms: D001151:Arsenic / Q000032:analysis*; D004784:Environmental Monitoring; D005544:Forecasting; D060587:Groundwater / Q000032:analysis*; D006863:Hydrogen-Ion Concentration; D016015:Logistic Models; D008281:Maine; D009566:Nitrates / Q000032:analysis; D010100:Oxygen / Q000032:analysis; D013431:Sulfates / Q000032:analysis; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D009566:Nitrates; D013431:Sulfates; D014874:Water Pollutants, Chemical; D001151:Arsenic; D010100:Oxygen