黄海近岸表层沉积物中PAHs的分布特征与潜在风险

利用第二次全国海洋污染基线调查数据,考察了我国黄海近岸海域表层沉积物中多环芳烃(PAHs)的分布状况、组成比例,并开展了初步的来源分析和潜在生态风险评价.研究结果表明,PAHs的含量范围从未检出至8294 ng·g-1,高值站点主要位于辽东半岛的大连湾附近海区,以及山东半岛北部的威海沿岸.在辽东半岛、山东半岛的近岸海区,表层沉积物中的PAHs以中、高环(4～5环)组分占据明显优势;而在江苏近岸海区,低环组分(2～3环)的比例明显上升.低环与中高环组分的相对丰度以及成对同分异构体的比值结果显示,各海区表层沉积物中PAHs的主要来源是各类燃烧释放过程,如燃煤、生物质、天然气和交通尾气等,石油产品输入的影响居次要地位.依据效应低值区间ERL的警戒水平,计算ERL商的平均值,从而初步得到各海区潜在的PAHs生态风险水平.结果表明,大连湾PAHs污染较为严重,各PAHs组分的浓度均高于ERL警戒水平,而苯并(a)芘甚至超出效应中值区间的境界水平ERM,显示大连湾近岸海区具有较高的PAHs生态风险,而其它海区的潜在生态风险则较低.

Distribution and potential risk of polycyclic aromatic hydrocarbons in coastal surface sediments from the Yellow Sea, China

Based on the second survey on marine pollution baseline performed by the State Oceanic Administration, China, the distribution and composition of PAHs in coastal surface sediments in Yellow Sea were investigated, and the source apportionment and potential ecological risk were preliminarily conducted. The results indicated that the total concentration of PAHs ranged from undetected to 8294 ngg1. The sites with high concentrations of total PAHs were mainly located in the coast of Dalian Bay and in the offshore area of Weihai. In the coastal areas of Liaodong Peninsula and Shandong Peninsula, median and high molecular weight components of PAHs with 4~5 rings were dominant in the surface sediments, while in the coastal areas of Jiangsu Province, the contribution of low molecular weight compounds with 2~3 rings increased obviously. The relative abundance between the low ring components and the median and high rings components as well as the isomeric ratios of paired compounds showed that the main source of PAHs in the coastal surface sediments was various pyrolytic procedures, such as combustion of coal, biomass and natural gas, and tail gas. According to the guideline levels of the effect low range (ERL), the calculated averages of ERL quotients were used to preliminarily evaluate the potential ecological risk in the different sea areas. The results revealed that among the different sea areas studied, PAHs pollution in Dalian Bay was the most severe, where all the levels of the studied PAH components exceeded the ERL guidelines, and the concentration of BaP even above the guideline of the effect median range (ERM); as a result, the ecological risk in this sea area was high, whereas it was relatively low in the other sea areas.