杭州湾表层沉积物中重金属空间分布特征与污染状况评价

本文对杭州湾海域2018年8－9月25个沉积物样品中的7种重金属含量进行了研究，结果表明，该海域表层沉积物中Cu、Pb、Zn、Cd、Cr、Hg和As含量平均值分别为22.50×10?6、21.93×10?6、63.39×10?6、0.10×10?6、48.32×10?6、0.05×10?6、5.45×10?6，所有评价因子的含量平均值均低于全国海岸带重金属的背景值。单因子污染指数法的评价结果显示，Cu、Pb、Zn、Cd、Cr、Hg和As的平均含量均符合第一类海洋沉积物质量标准，7种重金属的污染程度依次为:Cu>Cr>Zn>Pb>As>Hg>Cd。重金属富集程度分析结果显示，Cd、Hg和As的富集程度较低，Pb和Zn的富集程度相对较高。潜在生态风险指数法评价结果显示，杭州湾海域潜在生态风险等级为“较低”，海洋生态环境状况较好。表层沉积物中重金属和TOC相关性分析结果显示，该海域表层沉积物TOC含量与重金属Cu、Pb、Zn、Cd和Cr含量具有一定的正相关性。主成分分析法结果表明，前两个主成分的贡献率分别为64.42%和16.59 %；结合相关性分析表明，Cu、Pb、Zn、Cd和Cr主要的来源为工业生产与生活污水。

Concentration distribution and pollution assessment of heavy metals in surface sediments in Hangzhou bay

From August to September 2018, the distribution of 7 kinds of heavy metals in the sediment samples collected at 25 stations in Hangzhou bay was studied. The results showed that the average concentrations of Cu, Pb, Zn, Cd, Cr, Hg and As in the surface sediment were 22.50, 21.93, 63.39, 0.10, 48.32, 0.05 and 5.45×10?6, respectively. The average concentrations of all the evaluation factors were lower than the background values of heavy metals in the national coastal zone. According to the evaluated result by the single factor pollution index method of marine sediment quality, all the average contents of Cu, Pb, Zn, Cd, Cr, Hg and As were in the line with the class I standard of marine sediment quality. The pollution degree of the average contents of 7 kinds of heavy metals was Cu > Cr > Zn > Pb > As > Hg > Cd. According to the analysis result of heavy metal enrichment degree, the enrichment degree of Cd, Hg and As was relatively lower, and the enrichment degree of Pb and Zn was relatively higher. According to the evaluation result of potential ecological hazard index, the potential ecological risk index of Hangzhou bay was "low" and the marine ecological environment was in the good condition. The correlation analysis of heavy metals and TOC in the surface sediments showed that the TOC content in the surface sediments of the bay was positively correlated with the contents of heavy metals Cu, Pb, Zn, Cd and Cr. Based on the principal component analysis, the sources of heavy metal pollution in the sediments were further studied, and the contribution rates of the first two principal components were 64.42% and 16.59%, respectively. Combined with the correlation analysis, it was found that the main sources of heavy metal Cu, Pb, Zn, Cd and Cr were the pollution of industrial production and domestic sewage to marine sediments.