贵州草海喀斯特高原湿地水环境中典型抗生素的分布特征

Occurrence and distribution of typical antibiotics in the aquatic environment of the wetland karst plateau in Guizhou

为了初步探讨喀斯特地貌草海湿地环境中抗生素的污染水平、空间分布特征和生态风险,采用固相萃取和高效液相色谱-串联质谱法研究了地表水和沉积物样品中34种典型抗生素的含量水平,并通过风险商值法(RQ)进行生态风险评估.结果表明,33种抗生素在地表水中均有不同程度的检出,磺胺类、喹诺酮类、大环内酯类、氯霉素类和其他类抗生素的平均浓度分别为50.5 ng·L-1、43.2 ng·L-1、22.6 ng·L-1、15.9 ng·L-1和1.66 ng·L-1.喹诺酮类在沉积物中检出浓度最高,平均浓度为282 ng·g-1且高于地表水.在空间分布上,地表水呈现上游入湖口平均浓度(379 ng·L-1)高于下游出湖口平均浓度(50.4 ng·L-1);草海近岸区南侧沉积物中抗生素浓度高于湖心区和近岸区北侧.风险评估结果表明,单一抗生素SD、NOR、SAR、CTM、ROX和LIN等物质的RQs大于1呈高风险,SMX、SG、CIP、OFL、ENR和ERY等6种抗生素RQs在0.1≤RQs<1之间,呈中度风险;SMZ、SPD、FF和CAP等抗生素的RQs小于0.1;抗生素联合风险显示湖心区、南岸区以及出湖口呈现中度风险,其他近城市排污口呈高风险,抗生素联合风险商值明显高于单一抗生素的风险商值.整体看来,人类活动强度与草海水环境中抗生素的污染程度密切相关.

34 antibiotics in the surface water and the sediment of the Caohai wetland were detected using solid-phase extraction and high performance liquid chromatography tandem mass spectrometry,and ecological risk was assessed by risk quotients,in order to investigate the contamination levels,spatial distribution characteristics and ecological risks of antibiotics in the aquatic environment of the Caohai wetland karst plateau in Guizhou.Results showed that 33 antibiotics were detected in different degrees on the surface.Sulfonamides presented the highest average concentration(50.5 ng·L-1)among all antibiotics,followed by quinolones(43.2 ng·L-1),macrolides(22.6 ng·L-1),chloramphenicols(40.8 ng·L-1)and Others(1.66 ng·L-1),respectively.Quinolones was the major detected antibiotics in the sediments,with the highest average concentration of 282 ng·g-1,which was higher than the average concentration of surface water.Spatial distribution of antibiotics detected in the surface water of Caohai wetland showed that the lake entrance(upstream)was higher than the lake exit(downstream),with average concentrations of 379 ng·L-1,50.4 ng·L-1,respectively.The concentration of antibiotics in the sediments on the south side of the coastal area was higher than that of the lake center and near North side of the shore area.Risk assessment showed that the RQs value of SD,NOR,SAR,CTM,ROX and LIN was higher than 1,and the RQs SMX,SG,CIP,OFL,ENR and ERY were between 0.1 and 1,which presented the high risk and medium risk,respectively.However,the RQs value of SMZ,SPD,FF and CAP were less than 0.1,which presented the low risk.The combined risk of antibiotics showed moderate risk in the lake heart area,the south bank area and the lake exit.The pollution discharges of other near cities presented high risk,and the combined risk value of antibiotics was significantly higher than the risk quotient of single antibiotics.Overall,the intensity of human activity was closely related to the degree of contamination of antibiotics in grassy seawater environments.