Natural and Human Influences on Water Quality in a Shallow Regional Unconsolidated Aquifer, Northern Atlantic Coastal Plain

摘要: Data collected from more than 400 wells in the surficial unconfined aquifer Northern Atlantic Coastal Plain (New York through North Carolina) were compiled and analyzed to improve understanding of multiple natural human influences on water quality such shallow regional aquifers. The includes a variety land uses (including forest, agriculture, densely populated urban areas) hydrogeologic conditions. Unconfined ground commonly occurs within 20 30 feet surface, typically moves along relatively short flow paths local streams few decades. provides drinking many parts majority streams. Unconsolidated sediments composing are generally permeable areas, however, these areas is vulnerable influences. Water was evaluated at scale settings, flowpaths agricultural four selected settings. Insights gained studies useful for interpreting broader patterns variability observed scale. Geochemical identified described principal components analysis major ions, correlation logistic regression used relate concentrations nitrate pesticide compounds (atrazine, metolachlor, simazine, deethylatrazine, an atrazine degradate) volatile organic (VOCs) (chloroform, 1,1,1trichloroethane, tetrachlorethene, methyl tert-butyl ether) likely influences, as geochemical patterns, use, hydrogeology, soils. Variability ions related primarily ionic strength redox condition. Concentrations nitrate, pesticides, VOCs conditions, well distribution sources reflected use. Nitrate most common aerobic well-drained example; greater 0.4 milligrams per liter may result activities, although 3 areas. Atrazine, metolachlor also because ground-water geochemistry reflects soil conditions affecting transport table. Results demonstrate value information with other occurrence water. Such not unique Plain, observations interpretations relevant