Mobility of pharmaceutical compounds in the terrestrial environment: Adsorption kinetics of the macrocyclic lactone eprinomectin in soils

Avermectins, such as eprinomectin (EPM), are antiparasitic drugs widely and globally used. There is undisputed evidence that they could be a threat for the terrestrial ecosystem. Despite their global use, data for avermectins behaviour and fate in soils are scarce. The objectives of this research were to conduct adsorption experiments in the soil to determine kinetics and isotherms as well as to explore the EPM adsorption mechanism. Accordingly, various models were employed to study the adsorption behaviour and kinetics as well as the adsorption mechanism of EPM in soils. The results showed that the degree of EPM adsorption to soils is determined by the soils' physicochemical properties and the EPM initial concentration. It is possible that dissolved EPM concentration will be higher in soils that contain low amounts of clay minerals and organic matter, resulting in higher toxicity risk for the soil biota and shallow ground-water aquifers contamination. The results of this study are crucial for impact assessment of EPM and in the design of environmental fate or ecotoxicological studies. (C) 2015 Elsevier Ltd. All rights reserved.