Distribution And Risk Assessment Of Antibiotic Contamination In Chaobai River Basin,Beijing

Antibiotics have been widely used in the past few decades.Due to the increasingly serious problem of antimicrobial resistance,it has aroused global public health concerns.Suburban rivers receive large amounts of waste containing antibiotics,which are called reservoirs of antibiotics and antibiotic resistance genes in the environment.In this study,the watershed within the Chaobai River on the outskirts of Beijing was selected as the study area,including 22 sulfonamide antibiotics（SAs）,10 macrolide antibiotics（MLs）,16 quinolone antibiotics（QNs）,and 13 tetracyclines.（TCs）,15 beta-Lactam antibiotics（β-Ls）,5 polyether antibiotics,and 2 lincosamide antibiotics（LMs）,including 7categories and 83 antibiotics as target compounds for research The subject was detected by ultra-high performance liquid chromatography-mass spectrometry（LC-MS-MS）of83 antibiotics,combined with the characteristics of the hydrological characteristics of the Chaobai River Basin in Beijing,surrounding enterprises,and population patterns to study its water environment and sediments The pollution characteristics and distribution rules of antibiotics,and the risk entropy method is used to evaluate the risks to the environment and human health,and the following results are obtained:（1）44 and 21 antibiotics were detected in the water and sediments of Chaobai River Basin in Beijing,respectively,accounting for 53.01%and 25.30%of the target antibiotics respectively.The three main types of antibiotics detected in water and sediments are sulfonamides,macrolides and quinolones.Sulfonamides are the dominant species in water and macrolides are the dominant species in sediments.（2）There are seasonal differences in the concentration of antibiotics in water bodies and sediments,but the laws are completely different.Due to the erosion of non-point source pollution in the wet period,the concentration of antibiotics in the water body is mainly because the total concentration of antibiotics in the water body in the wet period is significantly higher than that in the dry period（p<0.05）.Macrolides are the dominant species in sediments and they are more likely to be adsorbed into the sediments,causing antibiotics to be more obvious in the dry season when the water level is lower（p<0.05）.（3）The spatial distribution of antibiotics in the waters of Chaobai River Basin in Beijing showed that the total concentration of antibiotics in the rivers entering the reservoir was significantly higher than that of the reservoir（p<0.01）.This may be because the river entering the reservoir is the main source of antibiotic pollution in the（4）reservoir.In sediments,except for sulfonamides and lincosamides,there is no significant difference in the overall spatial distribution of sediments during wet and dry periods.This is due to the complexity of sediment characteristics.（5）Different seasons,different residual media（water bodies,sediments）,different types of antibiotics,and physical and chemical indicators COD_Mn,TOC,TP and TN,NH₄-N and temperature are not the same,which is different from human and animal diseases.The occurrence rate and the nature of the sediment are related.（6）The results of the environmental risk assessment of antibiotics in the Chaobai River water body show that among all the antibiotics detected,AETM and SAL are antibiotics with higher potential risks.From the spatial distribution point of view,the cumulative ecological risks of reservoirs,tributaries of the Chaohe River and the tributaries of the Baihe River during the wet and dry periods are relatively low;the cumulative ecological risks of antibiotics in the Chaohe,Baihe and Chaobai Rivers and the tributaries of the Chaobai River are relatively high.The results of human health risk assessment show that antibiotics in the waters of the Chaobai River Basin have no potential health risks.