成渝经济区河流表层沉积物中多环芳烃的分布、来源及生态风险评价

Distribution,Source and Risk Assessment of Polycyclic Aromatic Hydrocarbons in River Sediment of Cheng-Yu Economic Zone

采用GC-MS分析了成渝经济区内六大水系(长江、岷江、沱江、涪江、渠江以及嘉陵江)中19个表层沉积物样品的16种美国EPA优先控制多环芳烃(ΣPAHs).结果表明,ΣPAHs的含量范围为48.2～723.1 ng/g(平均276.1 ng/g),最高值在长江流域石门子采样点,最低值在涪江流域百倾采样点.各流域表层沉积物中ΣPAH16含量总体趋势为:长江(358.6ng/g)>岷江(322.2 ng/g)>沱江(292.7 ng/g)>渠江(260.6 ng/g)>嘉陵江(240.2 ng/g)>涪江(82.4 ng/g).沉积物中PAHs组成为:2～3环占15.1%～52.3%、4环占24.4%～44.5%、5～6环占3.3%～56.9%.采用分子比值法cAn/c(An+Phe)、cFlA/c(FlA+Pyr)以及cInP/c(InP+BghiP)分析污染来源,表明各流域表层沉积物中PAHs主要源于草、木和煤的燃烧及石化产品的燃烧.采用表观效应阈值法进行生态风险评价,表明表层沉积物中的PAHs对生态环境的影响目前还处于较低风险水平.

The USEPA 16 priority pollutant dominated polycyclic aromatic hydrocarbons（PAHs） in the surface river sediments of Sichuan Province and Chongqing City in southwest China were determined using GC-MS.The result showed the content of PAHs in the sediment ranged from 48.2 ng/g to 723.1 ng/g,with an average value of 276.1 ng/g.Among which,the maximum content was found in Shimenzi of Yangtze River,the minimum content was found in Baiqing of Fujiang River.The content order of PAHs in the sediments followed Yangtze River（358.6 ng/g） Minjiang River（322.2 ng/g） Tuojiang River（292.7 ng/g） Qujiang River（260.6 ng/g） Jialing River（240.2 ng/g） Fujiang River（82.4 ng/g）.The vertical profiles of cAn/c（An＋ Phe）,cFlA/c（FlA ＋ Pyr） and cInP /c（InP ＋ BghiP） suggested the PAHs in this zone were mainly originated from pyrogenic source,the main sources of PAHs were petroleum combustion,biomass combustion,and coal burning.Risk assessment suggested that the PAHs in the sediment of this zone had no significantly biological impairment and low toxicological risk.