| Abstract: | Aldicarb was applied to soil columns in the laboratory which were leached by artificial rainfall. Concentrations of aldicarb, its sulphoxide and its sulphone in the effluent were measured by gas-liquid chromatography. The measured results were analysed in some detail using a computation model. Aldicarb and its oxidation products were very mobile in soil, a fact which could be well described after introducing very low sorption coefficients in the computation model. Aldicarb itself was converted at a high rate following first order kinetics (half-life about 2 days). The best approximations obtained for the rate constant of sulphoxide conversion in two soils were about 0.03 and 0.06/day respectively (half-lives 23 and 12 days). Only a rather wide range of possible values could be obtained for the rate at which sulphone was decomposed. |
