The Occurrence And Transformation Of Sulfonamide Antibiotics In Municipal Wastewater Treatment Plant

Pharmaceuticals and personal care products (PPCPs) in water environment have attracted wide attention at home and abroad. The drugs in their original structure or metabolites after human beings and animals used enter the municipal sewage treatment system through the urine and feces or toilet drainage. These micro-pollutants could be bound into the water environment with the sewage plant effluent and could occur and render adverse effects on ecosystem and human health, as the removal efficiencies of them in wastewater treatment plants are unsatisfactory nowadays. The reseach of distribution and migration of the antibiotics in sewage treatment plants is urgent and necessary. The migration and transformation of nine sulfonamide antibiotics in the municipal sewage plant were studied.On the basis of the literature and text, a method to simultaneously determine the nine sulfonamide antibiotics in the environmental samples using solid phase extraction and high performance liquid chromatography was developed. The Oasis HLB solid phase extraction column was used in this stuty and the factors of the pH of the aqueous solution, elution solvent, elution volume and elution speed were optimized. The mobile phase consisted of acetonitrile (A) and0.1%formic acid (B). The gradient elution program was as follows:0-14min,5%-60%A;14-15min,60%-5%A;15-18min,5%A. The column temperature was set to25℃and the flow rate was0.9ml/min. The injection volume was20u L and the separation was monitored at absorbance wave-length of268nm. Qualitative analysis of the method is accuracy, high sensitivity and good reproducibility for detection the sulfonamide antibiotics. The recovery of standard addition and the detection limits of the target compounds could meet the testing requirements of the antibiotics in the water environment.The method was applied to investigate the occurrences, distributions and the migration and transformation of the sulfonamide antibiotics in two local WWTPs. The results showed that all the eight sulfonamide antibiotics were determined in the influent, sedimentation tank and effluent water samples, with the level of0.36μ g/L-7.59μg/L and0.19μg/L-4.98μg/L. The detection rate of the sulfonamide antibiotics was high except sulfathiazole and sulfapyridine. Moreover, not less than five sulfonamide antibiotics were detected in the sludge samples, with the level of0.34μg/L-4.98μg/L. It is indicated that the sewage treatment plant has some effect on the removel of the sulfonamide antibiotics, but the removal efficiencies were unsatisfactory. The average removal efficiencies of sulfonamide antibiotics in two WWTP were56%-100%and47%-79%. Moreover the removal efficiencies of sulfadiazine, sulfadimidine and sulfadimethoxine were better, with the average removal efficiencies all above60%Additionally, studies on the hydrolysis, biodegradation, photolysis and adsorption of sulfonamide antibiotics in the aquatic environment were carried out. Base on the results, the migration and transformation of five sulfonamide antibiotics in municipal sewage treatment plants were studied. It was found that the hydrolysis behavior of sulfonamide antibiotics was not obvious, and there were a small amount of photolysis and biodegradation. The main degradation pathway of sulfonamide antibiotics in WWTP was sludge adsorption. The order of degradation rate of sulfonamide antibiotics were sludge adsorption> biodegradable> photolysis> hydrolysis.