Aldicarb Contamination of Groundwater

Aldicarb, [2-methyl-2-(methylthio)propionaldehyde O-(methylcarbamoy1)-oxime], the active ingredient in TEMIK® insecticide/nematicide, was discovered in 1962 (Weiden et al. 1965) and is currently registered in over 60 countries for a large number of crops. It is applied to the soil for nematode control and for insect or mite control as a result of its efficient translocation (systemic activity) by the plant. Toxic metabolites, primarily a result of soil microbial action, are the sulfoxide, [2-methyl-2-(methylsulfinyl)propionaldehyde O-(methylcarbamoyl)oxime], and the sulfone, [2-methyl-2-(methylsulfonyl)-propionaldehyde O-(methylcarbamoyl)oxime]. Aldicarb, aldicarb sulfoxide, and aldicarb sulfone are all white crystalline materials at room temperature with water solubilities of 6, 330, and 8 mg/mL, respectively (Hornsby et al. 1983).