Central California studies on the degradation and movement of aldicarb residues

Studies to measure the degradation and movement of aldicarb residues in the unsaturated and saturated zone were conducted during 1984 at three central California locations. These test sites, which consist of a tomato field near Manteca and vineyards near Livingston and Fresno are representative of conditions in central California under which aldicarb residues are most likely to reach drinking-water supplies.Results indicate that aldicarb residues degrade in the unsaturated zone with a half-life of 1.5–2.0 months. In areas with shallow water tables (less than three meters deep), traces of aldicarb residues may occasionally enter the upper one to five meters of the saturated zone where they degrade before reaching deeper, potable water supplies.