Migration and interaction of tetracycline and heavy metals on goethite-coated sand under dynamic flow conditions

Abstract

Abstract The antibiotic tetracycline (TC) can easily form intricate complexes with metal ions in the environment because it contains electron donor groups, which affect its environmental behavior. Based on static adsorption and desorption with the aid of column experiments, the migration and interaction of TC and metals (i.e., Cu and Cd) on goethite-coated sand (GCS) were investigated. Furthermore, the interaction between both pollutants was analyzed. A comparison of the migration behavior of TC and heavy metals on the GCS column showed that with increasing pH, TC migration increased. However, the migration of heavy metals decreased, which was mainly related to their hydrolysis. Heavy metals inhibited the migration of TC in the GCS column (the inhibitory effect of Cu was stronger than that of Cd), which was related to the stronger complexation of Cu. Similarly, TC also inhibited Cu migration on the GCS column, and the inhibitory effect was enhanced with increasing pH. At pH 3.0, TC had little effect on the migration of Cd, while at pH 5.5 and pH 8.0, the complexation of TC and Cd and their migration characteristics in GCS column enhanced Cd migration. This study contributes to a better understanding and prediction of the fates of antibiotics and heavy metals in the soil environment under complex contamination conditions. A theoretical basis for environmental risk assessment is also provided.