太湖及周边河流表层沉积物中PAHs的分布、来源与风险评价

Distribution, source and risk assessment of PAHs in surface sediments from Taihu Lake and its surrounding rivers

对太湖及周边河流表层沉积物中16种美国环保署优先控制的PAHs含量进行了检测和分析.结果表明,太湖沉积物中PAHs总量介于0.77~4.20μg/g之间,平均值为1.63μg/g,太湖周边河流沉积物中PAHs总量介于0.58~6.13μg/g之间,平均值为2.92μg/g.不同湖区沉积物中PAHs的空间分布差异显著,其中梅梁湾、贡湖湾以及东太湖沉积物中PAHs含量分别为(2.48±1.14)μg/g、(1.89±0.52)μg/g和(2.13±0.50)μg/g,周边河流中梁溪河、吴淞江及长兴港含量分别为7.34,6.13,5.54μg/g.利用低环/高环比值法、同分异构体比值法和主成分分析-多元线性回归(PCA-MLR)模型分析了污染源类型及贡献率,结果表明,太湖及其周边河流表层沉积物中PAHs主要来源为燃烧来源,太湖沉积物PAHs石油源贡献率为24%,燃烧源贡献率为76%,太湖周边河流石油源贡献率为41%,燃烧源贡献率为59%.使用沉积物质量标准法(SQSs)和Ba PE(Ba P当量浓度)对PAHs毒性进行评估,得出太湖及周边河流具有一定的潜在毒性,尤其是太湖周边河流.

The concentrations of 16 US EPA priority PAHs in surface sediments from Taihu Lake and its surrounding rivers were detected and analyzed. It was found that the total concentrations of PAHs in surface sediments from Taihu Lake ranged from 0.77 to 4.20μg/g, with a mean of 1.63μg/g, and the total concentrations in surrounding rivers ranged from 0.58 to 6.13μg/g, with a mean of 2.92μg/g. A significant difference of PAHs was found in spatial distribution from different lake sediments. The mean concentrations of Meiliang Bay, Gonghu Bay and the East Taihu Lake were 2.48±1.14μg/g, 1.89±0.52μg/g and 2.13±0.50μg/g, respectively, and the mean concentrations of its surrounding rivers Liangxi River, Suzhou River and Changxing Harbor were 7.34μg/g, 6.13μg/g and 5.54μg/g, respectively. Using the ratio method, the isomer ratio method, and Principal Component Analysis and Multiple Linear Regression（PCA-MLR）, this study analyzed the pollution sources and contribution rates, suggesting that the main source of PAHs in surface sediments from Taihu Lake and its surrounding rivers was the combustion source. The oil source contribution rate of Taihu Lake was 24%, and the combustion source contribution rate was 76%, while the oil source contribution rate of its surrounding rivers was 41%, and the combustion source contribution rate was 59%. Sediment quality criteria（SQSs） and Ba PE（Ba P equivalent concentrations） were employed to assess the toxicity of PAHs. It was concluded that Taihu Lake and it surrounding rivers had a certain potential toxicity, especially in its surrounding rivers.