长江口及毗邻海域沉积物中多环芳烃分布、来源及风险评价

PAHs in surface sediments from Yangtze River Estuary and its adjacent sea area:the distribution,sources and risk assessment

采用GC-MS联用技术分析了长江口及毗邻海域的表层沉积物样品中16种多环芳烃(Polycyclic Aromatic Hydrocarbon,PAHs)的质量比,对其组分、分布、来源及生态风险水平进行了探讨。结果表明,长江口及其毗邻海域PAHs的质量比为229.6～1 242 ng·g^(-1)(平均值为919.2 ng·g^(-1)),检出的16种PAHs均以4～6环为主,占PAHs总量的62.07%～89.28%;采用2～4环低相对分子质量与5～6环高相对分子质量的比值(Mr(LMW)/Mr(HMW)),荧蒽与芘的比值(Mr(FLUA)/Mr(PYR))分析PAHs的来源情况,结果显示研究区域中PAHs主要来源于石油源;采用国外沉积物质量评价方法的生物影响效应低值(Effects Range Low,ERL)和生物影响效应中值(Effects Range Median,ERM)对PAHs污染水平进行评价,研究区域PAHs的污染水平相对较低,对底栖生物产生危害风险的可能性较小。

Polycyclic aromatic hydrocarbon （PAHs） pollution in surface sediments of the Yangtze River Estuary and its adjacent sea area was investigated from 13 stations in June, 2006. Concentrations of 16 PAHs in the surface sediments were determined by GC-MS. All of the 16 PAHs have been detected in these samples. The sum of 16 PAHs concentrations identified were in the range of 229.6 - 1242 ng·g^- 1 , with mean value 919.2 ng·g^-1. The highest concentration of 1 242 ng· g^- 1 was observed in the surface sediments of Hl - 29a station and the lowest concentration of 229.6 ng· g^- 1 was found at XWH station. Among the 16 PAHs, higher residues of Benz[a] anthracene,Benzo [ ghi] pyrene, Dibenzo [ a, h ] anthracene, Pyrene and Phenanthrene were found in the sediments. The types of PAHs found in the surface sediments were mainly 4 6 tings PAHs by means of component analysis, accounting 62.07%- 89.28% of total PAHs. The component distributions, sources and pollution levels were investigated as well. Surface sediments at the station near to the sewage outlet contained highest amount of total PAHs. The ratios of LWM /HWM （low molecular weight PAH /high molecular weight PAH ） and fluoranthene/Benzopyrene （FLUA/PYR） were employed to diagnose the possible sources of PAHs. The results indicated that petroleum was the major source of PAHs in the surface sediments. Compared with other regions around the world, the degree of PAHs contamination for the investigated area was, in general, at low to moderate level. The ecological risk of surface sediment at Yangtze River Estuary and its adjacent sea area was assessed by comparing the effects range low （ERL） and effects range median （ERM） values of risk evaluation. The preliminary assessment showed that PAHs pose as a slightly high risk to the health of the marine inhabitants, while serious ecological risk has not presented in the surface sediments of the Yangtze River Estuary and its adjacent sea area.