Hydrogeology and ground-water-quality conditions at the Geary County landfill, northeast Kansas, 1988

Chemical analysis of water from monitoring wells upgradient and downgradient of the Geary County Landfill in Kansas near Junction City indicate the presence of several chemically distinct water types. For the dominant calcium bicarbonate water type, concentrations of inorganic and organic constituents indicate the presence of reducing conditions within the landfill and increased concentrations of calcium, magnesium, sodium, bicarbonate, sulfate, chloride, ammonia, iron, manganese, and other trace elements downgradient within a leachate plume that extends northeasterly away from the landfill. The orientation of the long axis of the leachate plume does not coincide with the August or September directions of groundwater flow, possibly due to the effect of abundant rainfall and high river stages at other times of the year or preferential flow in very transmissive zones, and thus may indicate the dominant direction of groundwater flow. None of the organic-constituent or inorganic-constituent concentrations exceeded secondary drinking-water standards. Concentrations of benzene, vinyl chloride, and 1,2-trans-dichloroethene exceeded Kansas notification levels. (USGS)