杭埠-丰乐河表层沉积物中多环芳烃的污染特征、来源分析及生态风险评价

Occurrence of polycyclic aromatic hydrocarbons(PAHs) in surface sediments from Hangbu-Fengle River:Pollution characteristics,potential source and risk assessment

对杭埠-丰乐河12个采样点的表层沉积物中16种优控多环芳烃(PAHs)的含量进行了测定.结果表明:16种PAHs均被普遍检出,总含量(∑PAHs)范围为71.3±15—3372±402 ng·g^(-1)干重(dw),平均值为938 ng·g^(-1)(dw),与国内主要河流相比其浓度处于中等水平.底泥中多环芳烃组成以4环和5环为主,共占∑PAHs的81%,其中,二苯并[a.h]蒽(DBA)浓度最高,平均浓度为254 ng·g^(-1).底泥总有机碳(TOC)与∑PAHs之间有良好线性关系.利用特征比值法和主成分分析探讨了PAHs的可能来源,结果显示,杭埠-丰乐河底泥中PAHs主要来自于流域周边居民生物质、煤燃烧及汽车燃油污染.利用沉积物质量基准法和苯并[a]芘毒性当量(TEQBa P)法分别评价了杭埠-丰乐河沉积物PAHs的生态风险和致癌风险,发现部分采样点某些多环芳烃含量超过了效应区间低值(ERL),具有潜在的生态风险;沉积物中TEQBa P均值高达343 ng·g^(-1),具有相当高的致癌风险.

In the present study,the concentrations of 16 priority PAHs in surface sediments from 12 sites of Hangbu-Fengle River were determined.The sixteen types PAHs were all detected in the sediment samples.The concentration of PAHs varied from 71.3±15 to 3372 ± 402 ng·g（-1）dry weight（dw） and the average was 938 ng·g（-1）（dw）,which suggested the pollution status was in the medium level compared with other major rivers and lakes in China.The composition of PAHs showed that 4and 5 ring PAHs were predominant,which accounted for 81% ∑PAHs.Dibenzo[a,h]anthrancene（DBA） was the most abundant PAH compound in the sediments,with an average concentration of254 ng·g（-1）（dw）.There was a linear correlation between ∑PAHs.concentrations and sediment TOC contents.Using characteristic ratio method and principal component analysis,the potential sources of PAHs were analyzed.Results suggested the PAHs in sediments from Hangbu-Fengle River were mainly from coal and wood combustions,gasoline and diesel emissions.The ecological risk and carcinogenic risk of PAHs in sediments from Hangbu-Fengle River were assessed by sediment quality guideline and the total toxic benzo[a]pyrene equivalent（TEQBa P）.Results demonstrated that some of PAHs exceeded ERL several sample sites,which has the potential ecological risk.The calculated TEQBa Pwas 343 ng·g（-1）,suggesting high potential risk from the sediments.