Hydrogeologic, water-quality, and land-use data for the reconnaissance of herbicides and nitrate in near-surface aquifers of the Midcontinental United States, 1991

Water samples were collected during the spring and summer of 1991 from 303 wells penetrating near-surface unconsolidated and bedrock aquifers of the midcontinental United States. Samples were analyzed for 11 herbicides, 2 dealkylated atrazine metabolites, and 4 nutrients. Specific conductance, pH, and dissolved-oxygen concentrations of the ground water were measured onsite. Ancillary data on well construction, hydrogeology, and land use also were obtained for each well.