Investigation Of Water Quality And Contamination Characteristics Of Sulfonamides Tetracyclines Antibiotics In The Surface Sediments Of Dishui Lake And Its Flowing Rivers

The fuzzy synthetic evaluation of water quality of Dishui Lake water system was carried out in this study. Developed and optimized the analytical methods to determinate sulfonamides and tetracyclines antibiotics in the surface sediments. At the same time, the potential ecological risk of 10 kinds of antibiotics in the surface sediments of Dishui Lake and its inflowing rivers was assessment. Hope for to provide help to the rational development, utilization and management of Dishui Lake in future.Evaluated the water quality of fuzzy synthetic evaluation method. The results indicated that the fuzzy synthetic evaluation values of grade Ⅴ were 0.435- 0.795, which meant the water pollution were serious in the area from Dazhi river, the diversion channel before and after the sluice to the wharf No.1 in Dishui Lake. The fuzzy synthetic evaluation values of grade Ⅳ and Ⅴ were 0.327 and 0.390 around the south island, which meant the water quality in this area belonged to grade Ⅴ also. Water quality in most areas of the lake belonged to grade Ⅳ. Agricultural pollution and the development of tourism were the two most important factors affecting water quality of the studies area. On the basis of established water quality index system, compared the fuzzy comprehensive evaluation method and the single factor evaluation method and the water pollution index method. The results indicated that the fuzzy comprehensive evaluation method can comprehensively consider the roles of each water quality factor in the overall evaluation, the contribution of different water quality factors to the comprehensive evaluation result is assigned according to the weight, and combination of fuzzy relation matrix of each water quality standard with the water quality factors. It can comprehensively judge the water quality category, reflect the fuzzy relation of water quality factor and water quality standard. It uses the precise mathematical method to deal with the fuzzy evaluation object, so that the evaluation result can be reliable.A ultrasonically extracted – solid-phase extraction – reversed phase high performance liquid chromatographic method was developed to determinate sulfonamides and tetracyclines antibiotics in the surface sediments by optimizing condition of pretreatment. The samples were freeze dried and milled with 100 mesh sieve, then accurately weighing 2g sample in 15 mL centrifuge tube. The mixture of methanol and EDTA-McIlvaine buffer(1:1) was divided for three times. Adding 10 mL of mixture, whirlpool mixing 1min, ultrasonic 20 min under 40 k Hz, centrifugal 10 min under 4℃ with 4000r/min, then transfer supernatant to brown bottle. Repeat the above steps again with added 8mL, 6mL mixture. All the supernatant were collected, then blow out the organic solvent with nitrogen under 40 ℃ until half of volume, then added 3mL water. Purification the concentrated liquid with Poly-sery HLB solid phase extraction column and collected the elution liquid. Then blowing the liquid after 0.5mL with nitrogen, used methanol determine the content of 1mL and then transferred to the brown bottle through the 0.45μm filter for RP-HPLC. The experimental results showed that the calibration curves of 7 sulfonamides were linear in the concentration range of 0.025-0.5mg/L(R2> 0.999), the recoveries at three added levels were from 71.4% to 107.6%, with relative standard deviations of 1.4%-5.2%, and the method detection limits(MDL) were from 0.07ng/g to 0.29 ng/g. The calibration curves of 3 tetracyclines were linear in the concentration range of 0.05-1 mg/L(R2> 0.999), the recoveries at three added levels were from 62.2% to 87.9%, with relative standard deviations of 1.1%-4.6%, and the method detection limits(MDL) were from 0.45ng/g to 0.58 ng/g. The results showed that the method was simple, rapid, accurate, reliable and was suitable to determine the sulfonamides and tetracyclines antibiotics in the sediments.The total concentrations of 10 antibiotics(dry weight) in the surface sediments of inflowing rivers changed obviously among different months, and the concentrations in autumn and winter was much more than that in spring and summer. While the fluctuation range of total concentration of antibiotics in the surface sediments of Dishui Lake was not obvious among seasons. The spatial distribution showed that antibiotics outside the gate of diversion channel [(23.13±29.95) ng/g] was higher than that inside the gate of diversion channel [(8.94±7.30) ng/g], and both were much higher than that in the Dishui Lake [(1.18±0.72) ng/g]. Sulfadiazine was the mostly detected element in the research area of antibiotics, followed by Sulfamethazine. Compared with other studies, the pollution of sulfonamides outside the gate of diversion channel was more serious. On the contrary, the antibiotics in the surface sediments inside the gate of diversion channel and Dishui Lake was at mild or no pollution levels. Preliminary ecological risk assessment indicated low or no ecological risk inside the gate of diversion channel and Dishui Lake except that serious risk was found in the Sansan highway station outside the gate of diversion channel.