Pesticide Adsorptionon Soil: Assessment of Calculation Methods
It is important to get correct results of adsorption coefficients, as the adsorption is the major process in order to describe the fate of pesticides in soil. In this study, Batch equilibrium method was compared with centrifugation method for measurement of adsorption by using pesticide (captan) on six different types of soil. The results showed that the batch method overestimates both adsorption and desorption process when compared to centrifugation method. This result explained by the use of low soil/solution ratios and extreme shaking process in batch method. The centrifugation method was accepted as more realistic method for the measurement of adsorption as it uses the high soil/solution ratios and more realistic experimental conditions. It is concluded that the overestimation of sorption leads the misinterpretation of adsorption and it may increase the probability of pesticide leaching into groundwater.
Keywords- Adsorption; batch method; captan; centrifugation method, pesticide