The Distribution,Transformation And Risk Assessment Of Typical Antibiotics In The Songhua River Basin Of Harbin Secion

In recent years,antibiotics have become important pollutants in the environment,and the resulting ecological risks,especially the potential threat to human health,has attracted increasing attention.Micro-antibiotics remaining in the environment can induce antibiotic-resistance bacteria(ARB),which can lead to bacterial resistance.Many researchers have found that sewage treatment plants are generally inefficient in removing antibiotic drugs.The result is that significant amounts of antibiotic drugs and metabolites directly enter environment.Therefore,antibiotics have become important pollutants in the aquatic environment.The Songhua River basin is one of 7 major river systems in China,with an international river with watershed area of 557,200 km2 and flows through the Chinese provinces Heilongjiang,Liaoning,Jilin and Inner Mongolia,with an annual runoff of 76.2 billionm3.The upstream region of the Harbin section of the Songhua River contains a developed livestock industry that accounts for over 40%of the total breeding stock in the whole Harbin region.The provincial capital,Harbin,is located upstream of the Harbin section,with a population of 5 million and a large antibiotics manufacturing facility.Downstream areas mainly depend on planting industries.Therefore,the Harbin section of the Songhua River basin presents a significant pollution and exposure risk for antibiotics.A method was established for coupled ultrasonic extraction,solid phase extraction-ultra performance liquid chromatography and mass spectrometry,to simultaneously detect 12 typical antibiotics belonging to 4 types(sulfonamides,macrolides,fluoroquinolones and cephalosporins)in surface water,waste water and sludge.The results show that the method was sensitive,accurate and stable,and can meet the testing requirements of antibiotics in water body and solid matrix.Studies had shown that there was antibiotic contamination in the basin,and sulfamethoxazole and cefazolin were the main pollutants in the basin.The detection of other antibiotics was low,but the detection rate was high,indicating that these antibiotics were widely used in this area.Antibiotics in article 11 primary tributary of the river basin showed that the distribution of the regional diversity of antibiotics released into environment,reveals the different areas of the economy,population,the development of animal husbandry,slaughtering and other imbalances,impact on the environment is not the same,should be targeted to control.The characteristic distribution and seasonal variation in antibiotic content was investigated in this basin,the results showed that the seasonal variation of antibiotics is obvious,with the highest levels in winter,lowest in summer,with no significant difference between levels in spring and autumn.The total concentrations of all 12 antibiotics in spring,summer,autumn and winter,were 39.7,9.6,27.5 and 136.2 ng/L,respectively.Seasonality was also observed in antibiotic distribution along the riverbank.The concentration of antibiotics during the ice cover is the highest,and the water body has the worst net effect,which should be taken seriously.The occurrence and distribution of typical antibiotics,from 18 of 23 sewage treatment plants in Harbin city,were studied.The results showed that these antibiotics were detected universally in the influents and effluents with concentration level differences.The research showed that in a large population,the total amount of antibiotics in hospitals in the dense urban sewage treatment plant is far lower than the less population,livestock and slaughtering developed surrounding area,revealing the livestock antibiotics than human emissions into the environment,should strengthen the regulation of this kind of industry.At the same time,the removal efficiency of antibiotics in wastewater treatment plants was not very high,indicating that the existing conventional wastewater treatment technology was not suitable for the removal of antibiotics.The potential for pollutants to create undesired environmental effects for aquatic organisms and the health risks to people of different ages caused by residual antibiotic contamination in the Songhua River were evaluated using the risk quotients(RQs)method.Results showed that all antibiotics were not high risk for biotoxicity,but some antibiotics were at medium risk and must be taken seriously.The health risk of antibiotics was far lower than 1,with no direct threat to human health established;however,the long-term risk deserves further evaluation.This study provides scientific information for domestic policy makers,helping them develop ecological protection strategies that may significantly support international cooperation in environmental protection.