Investigation of Aldicarb in Ground Water in Selected Areas of the Central Sand Plain of Wisconsin

Abstract
The goal of this study was to provide a preliminary assessment of the occurrence and movement of the pesticide aldicarb in ground water in the Central Sand Plain of Wisconsin. Aldicarb concentrations in ground water beneath three main study fields and two subsidiary fields were monitored during the period December 1980–August 1981. A total of 67 well points, some nested, and one multilevel sampler were installed for this study. In addition, 25 private wells and seven irrigation wells were sampled.The data collected to date are limited both in space and time. However, several trends are evident: (1) highest concentrations of aldicarb were detected in shallow monitoring wells (those located immediately below the water table); (2) no aldicarb was detected in any of the deep monitoring wells (those located roughly 60 feet below the water table), although aldicarb was found in some of the irrigation wells finished at approximately the same depth; (3) aldicarb seems to be concentrated in roughly a 5‐foot layer near the water table, and (4) marked seasonal fluctuations in aldicarb concentrations occurred in several wells.