Sulfonamides and tetracyclines in livestock wastewater

Antibiotics (sulfonamides and tetracyclines) have attractive increasing attention due to their persistence for a long time, which lead to concern of widespread antibiotic resistant bacteria and resistance genes in the aquatic environment. Investigation of the occurrence and elimination of antibiotics in the wastewater treatment plant (WWTP) effluent is thus imperative. This paper presents the method development of the liquid chromatography-ion-trap mass spectrometer (IT-MS)-time-of-flight mass spectrometer in series (LC-IT-ToF/MS) hybrid technique to determine concentrations of sulfonamides and tetracyclines in the effluent of animal WWTP. Detection limits of the developed method were 22.8, 23.0, 25.8, 23.6, and 9.8ngL^-1 for sulfathiazole, sulfamethazine, sulfamethoxazole, oxytetracycline, and chlortetracycline, respectively. Average recovery efficiencies of the method for sulfonamides fortified in effluent samples of ananimal WWTP at 1.0, and 4.0μgL^-1 were 73-95%, and 89-104%, respectively, while that of the method for tetracyclines fortified at 0.4 and 4.0μgL^-1 was 76-104%, and 101-107%, respectively. The analysis of effluent of the WWTP showed that more than 90% of analyzed antibiotics were removed by the treatment consisted of biological, a UF membrane, and a coagulation process. The maximum concentrations of sulfonamide and tetracycline in the WWTP were 49.5 and 4.1μgL^-1, respectively.