Highly porous ceramic media can be effective to remove contaminants from agricultural waters. In this study, these sorbent media were tested for their efficiency to remove three representative pharmaceuticals (i.e., lincomycin, sulfamethazine and tetracycline) from water. Results reveal that the tested media demonstrated relatively effective sorption for the selected pharmaceuticals from water. Tetracycline manifested the greatest sorption, followed by lincomycin and sulfamethazine. A granular medium was identified to have great removal efficiency for the selected pharmaceuticals, and could be potentially employed to remove pharmaceuticals from agricultural drainage water.The widespread tetracyclines in the environment have been considered to be responsible for the development of antibiotic resistance in microorganisms. At contaminated sites multiple tetracyclines are commonly found, and could collectively impact microbial populations. The uptake of different types of tetracyclines by Escherichia coli exerted varying levels of selective pressure on the bacteria to express antibiotic resistance, following the order of tetracycline > chlortetracycline > oxytetracycline. Linear relations between promoter activity and intracellular tetracycline concentration were observed except for anhydrotetracycline. The mixture of tetracyclines generally demonstrated additive effects on the E.coli bioreporter for expression of antibiotic resistance. These results suggest that the risk levels of antibiotic resistance invoked by exposure to tetracycline mixtures could be additive.
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