Degradation of abamectin and doramectin in sheep faeces under different experimental conditions

Abstract

Avermectins is the collective name given to a range of animal health products used in the prevention of parasitosis. Residues of these drugs retain their insecticidal properties after excretion in livestock faeces. We investigated the degradation of abamectin and doramectin in sheep faeces under the laboratory and field conditions. In the first two, out of three experiments, we exposed collective abamectin or doramectin contaminated and homogenised faeces samples to laboratory (UV light; l = 370 nm) and to field conditions on sheep pasture (exposed on the plate or put directly on the soil). The third experiment focused on degradation of both avermectins excreted via sheep faeces directly to the pasture. The degradation of both substances was evident in both cases, either under laboratory or under field conditions. The results show that degradation process is affected by physical properties of the faeces and weather conditions.