Contamination Characteristics And Ecological Risk Assessment Of Typical Antibiotics In The Water Of The Hongze Lake

During recent years, great concideration has been given to the issue of antibiotic residues in environment and its ecological risk. Studies on contamination characteristics of antibioticss have been carried out nationwide, including waters in Beijing, Liaoning, Jiangsu, Guangzhou and Sichuan Province. Hongze Lake one of the main fish farming base in China, is inevitable exposed to antibiotics pollution, but the contamination characteristics and ecological risk of antibiotics pollution is unclear in the area. Therefore, the contamination characteristics and ecological risk of 5 antibiotics, including Norfloxacin(NOR), Enrofloxacin(ENR), Ofloxacin(OFL), Ciprofloxacin(CIP) and Oxytetracycline(OTC), in wet-season and dry-season was studied. The results obtained were summarized as fo1lows:(1) Throμgh the optimization of cone voltage, collision energy, mass spectrometric parameters and liquid chromatographic separation conditions, A method was established for the simulta neous analysis of Norfloxacin,Oxytetracycline, Enrofloxacin, Ofloxacin and Ciprofloxacin with high performance liquid chromatography tandem mass spectrometry( HPLC-MS/MS). Using ORB-AX C18 liquid chromatography column(4.6mm * 150 mm * 5 0um). Under the optimized conditions of the instrument,to get the liner equation of 5 antibiotics,correlation coefficients higher than 0.99.(2) Only two kinds of antibiotic( Norfloxacin and Enrofloxacin) were detected in the study area on the Huai River Estuary of Hongze Lake, In wet-season Norfloxacin(NOR) detectable concentration was 14~579ng/L, the concentration of fish farms was 136~579ng/L.In dry-season Norfloxacin(NOR) detectable concentration was 4.9ng/L~60ng/L, the concentration of fish farm was 8.5~60 ng/L.Enrofloxacin(ENR) was only detected in the wet-season and the concentration was in a low level 1~10ng/L,NOR is the main antibiotic pollution in this area. Meanwhile the influent and the effluent of the Laozishan town sewage treatment plant were detected.4 kinds of antibiotics were detectable including Norfloxacin(NOR), Enrofloxacin(ENR), Ofloxacin(OFL) and Ciprofloxacin(CIP). The traditional sewage treatment process of high concentration>280 ng/L.NOR removal effect is very low<4%, at a low concentration NOR(<41ng/L) and other three(ENR,OFL,CIP) antibiotic removal rate were more than 77%.To detect the sediment in dry season,sediment antibiotic distribution trend is consistent with the water.(3) The European medicine ecological risk assessment technology was used to predict the ecological risk of Norfloxacin(NOR), Enrofloxacin(ENR),Ofloxacin(OFL), Ciprofloxacin(CIP) and Oxytetracycline(OTC) in the water. Ecological risk assessment revealed that in the wet-season, NOR in the fish farms may present high ecological risk to the environment.During the dry-season NOR in the fish farms may present medium ecological risk to the environment. The EMEA model is used to predict the antibiotics concentration in sediment, Predicted results is as 1000 times as in water,but far less than the measured values.