Single and ternary competitive adsorption-desorption and degradation of amphenicol antibiotics in three agricultural soils.

Abstract

The widespread usage of veterinary antibiotics results in antibiotic contamination and increases environmental risks. This study was evaluated the single and ternary competitive adsorption-desorption and degradation of three amphenicol antibiotics (AMs): chloramphenicol (CAP), thiamphenicol (TAP), and florfenicol (FF) in three agricultural soils. The adsorption capacity of amphenicol antibiotics in the soil was weak, and the Kf value was in the range of 0.15-3.59\xa0μg1-1/nL1/n kg-1. In the single adsorption-desorption experiment, the ranked order of adsorption capacity was TAP\xa0>\xa0FF\xa0>\xa0CAP. However, in the ternary competitive adsorption experiment, the order was changed to be CAP\xa0>\xa0FF\xa0>\xa0TAP. The degradation of AMs in soils was performed at various conditions. All AMs were vulnerable to microbial degradation in soils. A higher initial concentration would reduce the degradation rate and enhance the persistence of AMs in soil. The degradation of AMs was positively influenced by changes in soil moisture content and culture temperatures up to 30\xa0°C and decreased at higher temperatures. An equation was used to predict the leachability of AMs in soils and assess their risk to the water environment. The weak adsorption capacity and poor persistence of FF indicated that it may have a strong effect on groundwater based on the equation. It is imperative to further assess the biological impacts of FF at environmentally relevant concentrations given its mobility and extensive use in the livestock industry.