Kinetic study on triazophos adsorption in soil and its persistence behaviour in different environmental segments

The kinetics of triazophos adsorption on soil was studied using a batch adsorption technique. For assessing the fate of pesticide distributed in soil and in aqueous segments during the adsorption and desorption process, laboratory persistence studies were also conducted. Applicability of the pseudo-second order kinetic model suggests that the adsorption was a complex process and a chemisorption mechanism might be involved. Persistence results in distilled water indicate that 26.5 and 35.9% of the initial pesticide amount remained even after 45 days under transparent (half-life 7.8 days) and dark (half-life 17.8 days) conditions, respectively. In soil, 59.2% of the triazophos amount was dissipated after 50 days with a half-life of 31.9 days. Both the persistence studies in soil as well as in water could be described mathematically by the first order bi-phasic kinetic model. The study can be helpful in evaluating the dose of triazophos for agricultural applications.