上海郊区典型河道卤代烃类消毒副产物污染特征与生态风险研究

Pollution Characteristics and Ecological Risks of Halogenated Hydrocarbon Disinfection Byproducts in Typical River Channels in Shanghai Suburbs

消毒副产物(DBPs)随着消毒剂的大量使用而不断产生,DBPs持续输入水环境中,会对水生态系统产生潜在风险。以上海郊区典型河道太浦河及其周边河道为研究对象,采用顶空-气相色谱-质谱法对9个点位水体中7种典型DBPs的浓度水平进行了测定,并基于典型DBPs对淡水水生生物的急性和慢性毒性数据,采用物种敏感分布法(SSD)和风险评价因子法(RAF)推导出预测无效应浓度(PNEC),结合风险商值法(RQ)开展水生态风险评估。结果表明,冬季7种DBPs在所有点位中均有检出,总浓度范围为198.42~1201.86 ng·L^(-1);夏季,除三溴甲烷(TBM)外,其余DBPs检出率均有不同程度下降,二氯甲烷(DCM)和四氯化碳(CTC)在9个采样点均未检出,7种卤代烃类DBPs总浓度范围为5.81~40.62 ng·L^(-1),即表明冬季典型河道水体中DBPs的检出率和浓度均普遍高于夏季。生态风险评估结果表明,夏季太浦河及周边河道中7种DBPs的水生态急性和慢性风险均较小(lg(RQ)<-1),但冬季,太浦河干流点位TCM的慢性lg(RQ)在-1~0之间,对水生态系统存在潜在中等风险,需进一步加强监测与评估。

Disinfection by-products(DBPs)are continuously produced with the use of disinfectants and imported into the water environment,bringing potential risks to the water ecosystem.In this paper,the research object is the Taipu River and its surrounding watercourses in the suburbs of Shanghai.In that regard,the concentration levels of seven typical DBPs in water bodies across the nine sites were determined by headspace gas chromatography-mass spectrometry.Based on the acute and chronic toxicity data of typical DBPs to freshwater aquatic organisms,the predicted non-effect concentration(PNEC)was deduced through the species sensitivity distribution method(SSD)and risk assessment factor method(RAF).Then,the risk quotient method(RQ)was combined to execute the water ecological risk assessment,yielding results that detected seven types of DBPs in all sites in winter,and the total concentration ranged from 198.42 to 1201.86 ng·L^(-1).During summer,the detection rates of DBPs,apart from bromomethyl tribromide(TBM),were reduced to varying degrees.Meanwhile,methylene chloride(DCM)and carbon tetrachloride(CTC)were not detected in the nine sampling points.Furthermore,the total concentration of the DBPs of seven halogenated hydrocarbons ranged from 5.81 ng·L^(-1)to 40.62 ng·L^(-1).Generally,it highlights that the detection rate and concentration of DBPs in typical river water in winter are higher than those in summer.The findings of the ecological risk assessment exhibited that the acute and chronic risks of seven DBPs in Taipu River and its surrounding channels were small(lg(RQ)<-1)in summer.In contrast,the chronic lg(RQ)of TCM in the main stream of Taipu River during winter ranged between-1 and 0,indicating a potential moderate risk to the aquatic ecosystem,which necessitates further monitoring and assessment.