Adsorption of diuron, imidacloprid, procymidone and pyrimethanil on Mediterranean soils

The investigations here presented focus on the adsorption processes of proc ymidone, imidacloprid, diuron and pyrimethanil on soils from some Mediterra nean areas of Southern Europe with a range of climatic conditions regions. The assessment of the environmental fate of pesticides requires the study o f pesticide behaviour in soil. Taking into account that leaching of a pesti cide depends, among other factors, on its mobility, which is commonly descr ibed by the soil-water partition coefficient (Kd), it is necessary to make an accurate description of the distribution of chemicals between adsorbed a nd solution phases. In this sense, adsorption measurements provide data set s of important additional information to be used to assess the validity of existing models and to get realistic data on leaching. The results obtained will enable us to determine the adsorption capacities of the soils and est ablish a correlation with the organic carbon content of the samples. From t hat correlation, the K-OC values have been also calculated. According to al l data, diuron and procymidone are less mobile than imidacloprid (364, 533 and 128 L kg(-1), respectively), having pyrimethanil an intermediate behavi our (294 L kg(-1)).