杭州湾及其邻近海域表层沉积物重金属分布特征与污染评价研究

发布时间：2017-12-28 17:02

本文关键词：杭州湾及其邻近海域表层沉积物重金属分布特征与污染评价研究　出处：《浙江大学》2015年硕士论文　论文类型：学位论文

【摘要】：为掌握杭州湾及其邻近海域重金属迁移转化规律,客观评价重金属污染状况及有效控制杭州湾重金属生态风险,本文对1996～2012年春季杭州湾及其邻近海域表层沉积物中Cu、Pb、Zn、Cd、Hg、As 6种重金属含量的时空分布特征及其影响因素进行了研究,并采用主成分分析法判别了重金属的可能来源,采用地累积指数法、沉积物质量基准法和潜在生态风险指数法评价了污染状况和生态风险。主要结论如下：(1)2012年杭州湾及其邻近海域表层沉积物中Cu、Pb、Zn、Cd、Hg、As 6种重金属均值大小分别为23.2±8.48 mg/kg,26.3±6.05 mg/kg,78.4±17.8 mg/kg, 0.112±0.043 mg/kg,0.080±0.031 mg/kg,8.27±3.99 mg/kg(2)空间分布趋势表明,杭州湾及其邻近海域表层沉积物中Cu、Pb、Zn、 Cd、As 5种重金属总体表现一致,局部存在差异,主体上呈现出以南汇嘴附近海域为高值区,东部和北部的砂质沉积海域为低值区。Hg在长江口南支入海口和杭州湾口北岸未呈现明显的高值区,在舟山东南海域出现了明显的高值区。(3)历史变化趋势表明,自1996年以来,杭州湾及其邻近海域表层沉积物中Pb含量呈上升趋势；Cu、Zn、As含量在2001～2009年期间均表现出了上升趋势,2009年以后则呈下降趋势；Cd、Hg含量有一定波动但总体保持稳定。(4)基于历史数据采用数理统计法确定了Cu、Pb、Zn、Cd、Hg、As的环境背景值,分别为20.6、21.0、80.5、0.102、0.039、9.99mg/kg。(5)各金属元素之间基本呈显著或极显著正相关,来源具有相似性。其中陆源碎屑颗粒的输送对研究区域表层沉积物中重金属的组成和分布具有决定性的意义,同时重金属在不同介质间转换及硫化物富集作用对沉积物重金属来源也有一定贡献。(6)杭州湾及其邻近海域表层沉积物重金属总体潜在风险水平为中等,Hg和Cd是主要生态风险贡献因子。6种重金属中Cu、Pb、Zn、As潜在生态风险水平为低,Cd为中等,Hg为强。潜在生态风险指数(RI)相对高值区主要分布舟山群岛东南部、长江南支入海口及杭州湾口北岸。
[Abstract]:In order to grasp the Hangzhou Bay and its adjacent sea migration and transformation of heavy metals, heavy metal pollution evaluation and effective control of Hangzhou Bay ecological risk of the heavy metals, the paper studied 1996 spatial distribution characteristics and its influence to the spring of 2012 in Hangzhou Bay and adjacent waters in the surface sediments of Cu, Pb, Zn, Cd, Hg, As 6 kinds of heavy metal content factor and discriminant analysis method of possible sources of heavy metals by using principal components, the index of geoaccumulation, sediment quality criteria and the potential ecological risk index to evaluate the pollution and ecological risk. The main conclusions are as follows: (1) 2012 in Hangzhou Bay and adjacent waters in the surface sediments of Cu, Pb, Zn, Cd, Hg, As 6 kinds of heavy metals in the mean sizes were 23.2 + 8.48 mg/kg 26.3 + 6.05 mg/kg 78.4 + 17.8 mg/kg 0.112 + 0.043 mg/kg 0.080 + 0.031 mg/kg 8.27 + 3.99 mg /kg (2) the spatial distribution trends indicate that Hangzhou Bay and adjacent waters in the surface sediments of Cu, Pb, Zn, Cd, As 5 kinds of heavy metals in the overall performance, local differences, the main show to the waters near the Nanhui mouth high value area in eastern and northern waters for the low value area of sandy sediments. There is no obvious high value area of Hg in the southern branch of the Yangtze Estuary and the North Bank of the Hangzhou bay mouth, and there is an obvious high value area in the southeast of Zhoushan. (3) shows that the historical trend, since 1996, increased the content of Pb in Hangzhou Bay and its adjacent sea sediments; Cu, Zn, As content in the period from 2001 to 2009 showed a rising trend, after 2009 decreased; Cd and Hg contents have certain fluctuation but remained stable overall. (4) based on historical data, the environmental background values of Cu, Pb, Zn, Cd, Hg and As were determined by mathematical statistics, which were 20.6, 21, 80.5, 0.102, 0.039 and 9.99mg/kg, respectively. (5) there is a significant or extremely significant positive correlation between the metal elements, and the origin is similar. The transport of terrigenous clastic particles is decisive for the composition and distribution of heavy metals in the surface sediments of the study area. Meanwhile, the conversion of heavy metals in different media and the enrichment of sulfide also contribute to the source of heavy metals in sediments. (6) the overall potential risk level of heavy metals in the surface sediments of the Hangzhou Bay and its adjacent waters is moderate, and Hg and Cd are the main contributors to the ecological risk. The potential ecological risk levels of Cu, Pb, Zn and As of the 6 heavy metals were low, Cd was medium, and Hg was strong. The relative high value area of the potential ecological risk index (RI) mainly distributes in the southeast of the Zhoushan archipelago, the South Branch of the Yangtze River and the North Bank of the Hangzhou bay mouth.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X55

【参考文献】