Estimated concentrations of atrazine in shallow groundwater

This map shows estimated concentrations of atrazine in shallow groundwater beneath agricultural land. Atrazine use is one of the most important factors used to predict atrazine and deethylatrazine concentrations in groundwater (right). Within areas of high atrazine use, groundwater residence time, soil permeability, and other factors explain some of the differences in predicted concentrations. From USGS Circular 1360.