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重金属是海洋沉积物中一类主要的污染物,其累积和释放能对水生生物和人体健康产生较大的负面影响。本研究针对2007年在广西北海近岸海域获得表层沉积物的重金属数据首先分析了它们的含量和空间分布特征,然后采用地质累积指数法和潜在生态危害指数法对其污染程度和潜在生态危害进行评价,最后应用主成分分析法推断了各重金属的主要来源。结果表明,广西北海近岸海域沉积物的重金属含量与前人研究相比总体变化不大,仅有Cr和As两种元素在部分区域超过沉积物标准第二类和第一类指标值。Pb、Zn和Hg之间相关性显著。大部分重金属含量在研究区的西北部和东边中部偏高,明显受到了陆缘输入和北部河流入海效应的影响。研究区的重金属污染程度总体上较低,为低潜在生态危害等级。有机物贡献及沉积物对海水中重金属的吸附是Zn、Pb、Cd、As和Hg元素在研究区表层沉积物的主要来源,Cu和Cr可能更多来源于本地沉积物自身。
Heavy metals are one of the major pollutants in marine sediments. Their accumulation and release can have a significant negative impact on aquatic organisms and human health. In this study, we first analyzed the content and spatial distribution of heavy metals in surface sediment from the coastal waters off the Beihai coast of Guangxi in 2007, and then used the method of geo-accumulation index and potential ecological risk index to study the pollution degree and potential ecological risk Evaluation, the final application of principal component analysis deduced the main source of heavy metals. The results show that the contents of heavy metals in the sediments near the Beihai coast of Guangxi have not changed much compared with the previous studies. Only the Cr and As elements surpass the second and first indexes of sediment standard in some areas. The correlation between Pb, Zn and Hg was significant. Most of the heavy metal content is high in the northwestern part of the study area and the middle of the east part, which is obviously affected by the input of the continental margin and the inflow of sea into the northern rivers. The heavy metal pollution in the study area is generally low, which is a low level of potential ecological risk. Organic matter contribution and sediment adsorption of heavy metals in seawater are the main sources of Zn, Pb, Cd, As and Hg elements in the surface sediments of the study area. Cu and Cr may originate from the local sediment itself.