Influence of natural and human factors on pesticide concentrations in surface waters of the White River Basin, Indiana

Pesticide concentrations in surface waters of the White River Basin are affected by natural and human factors. For example, concentrations of atrazine, a herbicide widely used on corn in the White River Basin, tended to be higher in an agricultural basin with permeable, well-drained soils, than in an agricultural basin with less permeable, more poorly drained soils. Concentrations of butylate, another herbicide used on corn, were substantially higher in an agricultural basin in the southern part of the White River Basin than in an agricultural basin in the central part of the White River Basin, corresponding to the higher use of this compound in southern Indiana. Concentrations of diazinon were substantially higher in a predominantly urban basin than in two predominantly agricultural basins, corresponding to the common use of this insecticide on lawns and gardens in urban areas.