北京市城市河流中抗生素的污染特征及多层次生态风险评估

Pollution Characteristics and Multilevel Risk Assessments of Antibiotics in the Urban Rivers of Beijing,China

为评估北京市河流中抗生素的污染特征和生态风险,利用固相萃取结合高效液相色谱串联质谱检测了4类共35种常见抗生素的浓度水平,并利用风险商法(RQ)和联合概率曲线法(JPCs)评估了抗生素的生态风险.结果表明,北京市10条河流地表水中共检测出33种抗生素,总浓度范围是N.D.~1573.57 ng·L^(-1),磺胺甲唑的浓度最高(N.D.~160.04 ng·L^(-1)),其次为磺胺嘧啶(0.09~147.90 ng·L^(-1))和氧氟沙星(0.28~94.72 ng·L^(-1)),其中检出率>50.0%的抗生素有16种;RQ法显示有12种抗生素存在生态风险,四环素、克拉霉素和甲氧苄氨嘧啶的风险最高,其风险商分别为3.99、1.86和1.01,污水处理厂出口的风险高于其所在河流干流的风险.四环素、克拉霉素和甲氧苄氨嘧啶的预测无效应浓度超标率均为2.3%,基于JPCs发现,克拉霉素的最大风险乘积为1.66%,对0.3%~7.0%的物种具有低等风险,其余抗生素的风险可忽略.抗生素的检出率、浓度分布、最敏感物种和物种敏感性分布对生态风险评估具有重要影响,采用多层次生态风险评估法能有效避免保护不足和过保护现象,有助于在全区域范围内对抗生素进行分级和分区管理.

To comprehensively assess the pollution characteristics and ecological risks of antibiotics in the rivers in Beijing,the concentrations of 35 common antibiotics belonging to four categories were quantified by using solid phase extraction combined with high-performance liquid chromatography-tandem mass spectrometry.The ecological risks of antibiotics were evaluated using the methods of risk quotient(RQ)and joint probability curves(JPCs).The results showed that a total of 33 antibiotics were detected in the surface water of ten rivers in Beijing,and the total concentrations of antibiotics ranged from N.D.to 1573.57 ng·L^(-1).Sulfamethoxazole showed the highest concentration(N.D.-160.04 ng·L^(-1)),followed by sulfadiazine(0.09-147.90 ng·L^(-1))and ofloxacin(0.28-94.72 ng·L^(-1)).There were 16 antibiotics with a detection frequency greater than 50.0%.The RQ method showed that there were 12 antibiotics with potential ecological risks.Tetracycline,clarithromycin,and trimethoprim showed the highest risks,with RQs of 3.99,1.86,and 1.01,respectively.The risks of antibiotics at the outlets of wastewater treatment plants were higher than those in mainstream rivers.The PNEC exceedance rates of tetracycline,clarithromycin,and trimethoprim were above 2.3%.Based on JPCs,the maximum risk product of clarithromycin was 1.66%,and it showed low risks to 0.3%-7.0%of species.The risks of other antibiotics could be ignored.The detection frequency,distribution of concentrations,most sensitive species,and species sensitivity distribution of antibiotics had important impacts on the ecological risk assessment.Using the multilevel ecological risk assessment strategy can effectively avoid inadequate protection and overprotection and is also conducive to the hierarchical and zoning management of antibiotics throughout the region.