Acetamiprid retention in agricultural acid soils: Experimental data and prediction

The overuse of pesticides in agriculture has led to widespread pollution of soils and water resources, becoming a problem of great concern. Nowadays, special attention is given to neonicotinoids, particularly acetamiprid, the only neonicotinoid insecticide allowed for outdoor use in the European Union. Once acetamiprid reaches the soil, adsorption/desorption is the main process determining its bioavailability and environmental fate. Therefore, in this work, the adsorption/desorption behaviour of acetamiprid in 60 agricultural soils was studied. The results indicate that acetamiprid has a low affinity for soil constituents, with values ranging from 0.2 to 4.28 L kg^-1 for K_d(ads). At the same time, acetamiprid shows high desorption levels (up to 96.3%), indicating that it is poorly retained in soils, thus presenting high bioavailability and a potential risk for transport to other environmental compartments. Regarding the influence of soil properties on the adsorption/desorption process, soils with a high content of organic matter, clay, and exchangeable basic cations showed higher retention of acetamiprid, with greater adsorption and lower desorption. Finally, robust and universal models were successfully developed to predict the adsorption and desorption behaviour of acetamiprid in soil.