Soil characteristics and agrichemicals in groundwater of the Midwestern United States

A comprehensive set of soil characteristics were examined to determine the effect of soil on the transport of agrichemicals to groundwater. This paper examines the relation of soil characteristics to concentrations and occurr ence nitrate, atrazine, and atrazine residue from 99 wells completed in unc onsolidated aquifers across the Midwestern United States. Soil characterist ics that determine the rate of water movement were directly related to the occurrence and concentrations of nitrate and atrazine in groundwater. The s ubstantial differences in the relations found among soil characteristics an d nitrate and atrazine in groundwater suggest that different processes affe ct the transformation, adsorption, and transport of these contaminants. A m ulti-variable analysis determined that the soil characteristics examined ex plained the amount of variability in concentrations for nitrate (19%), atra zine (33%), and atrazine residue (29%). These results document that, althou gh soils do affect the transport of agrichemicals to groundwater, other fac tors such as hydrology, land use, and climate must also be considered to un derstand the occurrence of agrichemicals in groundwater.