北京市北运河流域河水和地下水多环芳烃分布规律及风险评价

Distribution and risk assessment of PAHs in river water and groundwater in North Canal basin of Beijing

为研究北运河流域河水与不同含水层地下水体中多环芳烃(PAHs)的相互作用,收集北运河流域上游温榆河段及下游北运河段不同季节的河水与地下水水质数据,采用对比分析及显著性分析方法研究河水与地下水中多环芳烃的组成、含量及时空分布特征,并利用风险熵法进行风险评价。结果表明:16种优控多环芳烃中,除苯并[a]芘和二苯并[a,h]蒽检出率不足100%外,其余14中多环芳烃污染物在河水、潜水和承压水中均全部检出;多环芳烃总质量浓度的构成以萘为主,质量浓度为1587.42ng/L,约占总质量浓度的85.6%;潜水和承压水春季多环芳烃总质量浓度显著低于夏季,2~3环多环芳烃质量浓度高于4环以上多环芳烃质量浓度;潜水中多环芳烃总质量浓度高于承压水;北运河段潜水中多环芳烃总质量浓度高于温榆河段;温榆河段地下水主要污染物为萘、芴和菲,北运河段地下水主要污染物为萘、苊和菲;上游河水多环芳烃总质量浓度低于下游,主要污染物为萘和菲;萘、芴、菲、蒽、荧蒽、芘、苯并[a]蒽在不同位置条件下差异显著,除苯并[a]蒽、苯并[b]荧蒽、苯并[a]芘和二苯并[a,h]蒽之外,其余多环芳烃在不同季节条件下均差异显著;通过风险熵法计算得出不同季节和位置条件下研究区生态风险相对较低。

To study the interaction of polycyclic aromatic hydrocarbons(PAHs)in river water and different groundwater aquifer,the water quality data of river water and groundwater in different seasons in upstream and downstream of Wenyu River in the North Canal basin were collected.The contrast analysis and significance analysis methods were used to study the composition,content,and spatial and temporal distribution characteristics of PAHs in river water and groundwater.Besides,the risk entropy method was used for risk assessment.The results showed that:the detection rate of PAHs in all 16 kinds of PAHs was 100%,except for BAP and Daha,while the other 14 PAHs were detected in river water,phreatic water,and confined water;the composition of PAHs was mainly Nap(1 587.42 ng/L),accounting for 85.6% of the total mass concentration;the total mass concentration of PAHs in spring was significantly lower than that in summer in phreatic water and confined water,the mass concentration of 2~3-ring PAHs was higher than that of 4-ring PAHs;the mass concentration of PAHs in the phreatic water of the North Canal was higher than that in the confined water of the Wenyu river.Nap,Flu,and Phe were the main pollutants in the groundwater of Wenyu river.Nap,Acy,and Phe were the main pollutants in the groundwater of the North Canal;the total mass concentration of PAHs in the upper reaches of the river water was lower than that in the lower reaches,and the main pollutants were Nap and Phe;Nap,Flu,Phe,Ant,Fla,Pyr,and BaA,respectively,had significant differences in different situations,except for BaA,BbF,BaP,and Dib,while the other PAHs had significant differences in different seasonal conditions;according to the risk entropy method,the ecological risk in summer was relatively low compared to different seasons and situations.