天津近岸海域表层沉积物中PAHs污染特征及风险

为掌握渤海湾天津段多条河流入海区和海滨旅游度假区的近岸海域表层(0~5 cm)沉积物中PAHs(多环芳烃)的污染状况,对该区域表层沉积物中16种US EPA(美国国家环境保护局)优先控制PAHs的分布特征及其来源进行了调查和分析,并评估了其潜在生态风险和概率致癌风险. 结果表明:渤海湾天津近岸海域表层沉积物中w(PAHs)(16种PAHs质量分数之和,以干质量计)为23.9~672.8 ng/g,平均值为228.1 ng/g. 表层沉积物中PAHs的污染程度与历史调查结果相比有所加剧,并且呈复合型污染,在天津港港区外海域主要为石油制品污染,在研究区域南部则主要源于燃煤和生物质的不完全燃烧. 风险评估结果表明,海河入海口附近和研究区域北部存在潜在生态风险；研究区域内概率致癌风险处于较低水平,∑₇TEQ_BaP(7种强致癌PAHs的苯并芘毒性当量浓度之和)占∑₁₆TEQ_BaP〔16种PAHs的苯并芘毒性当量浓度之和〕的96.8%,其中二苯并蒽的致癌风险最大,其次为苯并芘. 

Pollution Characteristics and Risk Assessment of Polycyclic Aromatic Hydrocarbons in the Surface Sediments of Tianjin Coastal Area, China

Bohai Bay is the second largest bay of Bohai Sea, and is semi-enclosed. The ecosystem has been adversely affected by the economic boom in the surrounding area. In order to understand the pollution status of polycyclic aromatic hydrocarbons (PAHs) in the Tianjin coastal area of multiple inflow rivers and the seaside tourist resorts in Bohai Bay, the distribution characteristics and resources of 16 US EPA priority control PAHs in the surface sediment (0-5 cm) of this region were analyzed, and their potential ecological risk and probabilistic carcinogenic risk were assessed. The results showed that the total concentrations of PAHs ranged from 23.9 to 672.8 ng/g dry weight, with an average of 228.1 ng/g. Compared with the pollution levels in the past years in the area, the pollution degree has an increasing trend. The resources of PAHs pollution varied in the different sections:the resources in the coastal area in Tianjin Port mainly originated from petroleum products, while the southern section was mainly affected by the incomplete combustion of coal and biomass products. There have been potential ecological risks near the estuary of Haihe River and the northern section. The probalistic carcinogenic risk for the studied area was on a lower level. Based on PAHs toxic equivalent concentration (TEQ_BaP), seven higher carcinogenic PAHs accounted for 96.8% of the total TEQ_BaP. Among them, dibenzoanthracene (DBA) had the maximum potential carcinogenic risk, followed by benzopyrene (BaP). The polluted levels of PAHs in Bohai Bay should be monitored routinely, since they are persistent organic pollutants and difficult to degrade in the environment.