Adsorption and mobility of veterinary compounds on Moroccan soil; Case of Ivermectin

Ivermectin (IVR) is an antihelmitic and anti-parasitic substance used mainly in veterinary medicine worldwide. Its release in the environment could have a negative effect on living organisms and generate soil and groundwater pollution. The main objective of this work aimed at the study of the adsorption of IVR on soil from Gharb region in Morocco. Sorption tests were carried out according to conventional guideline by varying the mass of the adsorbate and the pH of the solution. Analysis was made by UV-visible spectrophotometer. Adsorption kinetics of IVR was rapid and equilibrium was reached within 20 minutes. The Freundlich and Langmuir isotherms models were compared and adsorption constants were calculated. Comparison between the two models showed that Freundlich model fitted best data while kinetic data fitted pseudo-second order. Thermodynamically, sorption process of IVR on the examined soils would be exothermic and controlled by physisorption Tests of mobility have shown strong adsorption of IVR in the soils tested After 7 batches of water percolated, less than 2% of the applied quantity has been detected.