黄、东海陆架沉积物中重金属污染的长期记录与评价

发布时间：2018-02-02 11:41

本文关键词： 重金属污染背景值沉积物黄东海陆架　出处：《青岛科技大学》2014年硕士论文　论文类型：学位论文

【摘要】：重金属因生物毒性较大，能够在动植物体内长期累积，所以具有重要的环境学意义。而沉积物对水体重金属污染具有很好的指示作用，进入水体的重金属大部分经过悬浮物吸附并最终转移到沉积物中，所以可以通过沉积物表现出明显的时空分布规律。黄、东海陆架同时受到大洋和人类活动的影响，考虑到自19世纪中叶工业革命以来人类活动的影响明显增加，本文着眼于黄、东海陆架，将柱状沉积物分为断面A和断面B，去除粒度对沉积物重金属含量的影响，从时间和空间的角度分析重金属在该海域的分布情况。本次调查的站位分布于东海及黄海海域，所有样品分别由北斗号和东方红2号调查船采集，共设38个站位，包括表层样品30个，短采样柱7个，长采样柱1个。本文对采集的沉积柱芯进行了210Pb测定，并绘制出柱样中210Pb活度的垂直分布图，得到了沉积速率，利用沉积速率完成了210Pb测年；利用原子吸收法对所有样品进行了Cu、Pb、Zn、Cd四种重金属含量的检测；利用激光衍射法测得了经重金属检测的沉积物样品的比表面积。通过比较计算得出了沉积物重金属含量与比表面积的关系，进而修正了去除粒径影响的柱状样和表层样的重金属含量。通过210Pb测年得到了重金属含量随历史的变化进而推算了其重金属背景值，，进而修正了柱状样和表层样的重金属污染情况。通过本文的研究表明： 1、通过对沉积物重金属含量与其比表面积的比对和线性回归发现，沉积物重金属的含量与其比表面积有显著的正相关关系，并通过线性回归方程确定了相关系数，进而得到了比表面积与重金属含量的方程。通过该方程将不同比表面积的沉积物重金属浓度转化为单一比表面积的校正值。 2、通过对校正值的分析并与历史文献做参考可以发现近些年来沉积物中重金属含量有显著增加的趋势。而工业革命之前的含量未有较大变化。说明工业革命之后黄东海所调查区域有一定程度的污染。故也可将工业革命之前未较大变化的重金属含量值标定为理想未受污染的背景值。 3、通过对众多沿海站点的表层样的检测，并与求得的背景值进行比较，得出了黄东海沿岸重金属的污染情况。可以看出从离岸到近岸总体重金属含量的升高，并随海域水文等环境因素的影响呈局部变化的态势。间接反应出重金属污染的人为影响。
[Abstract]:Heavy metals have important environmental significance because of their high biotoxicity and can accumulate in animals and plants for a long time, while sediments have a good indication of heavy metal pollution in water bodies. Most of the heavy metals entering the water body are adsorbed by suspended solids and eventually transferred to the sediment, so they can show obvious temporal and spatial distribution law through the sediment. The East China Sea shelf is influenced by both ocean and human activities. Considering the obvious increase of human activities since the industrial revolution in the middle of 19th century, this paper focuses on the Yellow and East China Sea shelf. The columnar sediment was divided into section A and section B, and the influence of grain size on the heavy metal content in the sediment was analyzed. The distribution of heavy metals in the sea area was analyzed from the point of view of time and space. All the samples were collected by the Beidou and Dongfanghong 2 survey vessels, with 38 stations, including 30 surface samples and 7 short sampling columns. In this paper, 210Pb was measured and the vertical distribution of 210Pb activity in the sample was plotted, and the deposition rate was obtained. 210Pb dating was completed by using deposition rate. The contents of four kinds of heavy metals, CuPbPbZN and CD, in all samples were determined by atomic absorption spectrometry (AAS). The specific surface area of sediment samples detected by heavy metals was measured by laser diffraction method, and the relationship between heavy metal content and specific surface area of sediments was obtained by comparison and calculation. The contents of heavy metals in columnar and surface samples were corrected, and the background values of heavy metals were calculated by 210Pb dating. Furthermore, the pollution of heavy metals in columnar and surface samples was corrected. The results show that: 1. By comparing the heavy metal content with its specific surface area and linear regression, it was found that there was a significant positive correlation between the heavy metal content and its specific surface area. The correlation coefficient is determined by linear regression equation. Then the equation of specific surface area and heavy metal content is obtained, by which the concentration of heavy metal in sediment with different specific surface area is transformed into the correction value of single specific surface area. 2. By analyzing the corrected values and referring to the historical documents, we can find that the heavy metal contents in sediments have a significant increasing trend in recent years, but the contents before the industrial revolution have not changed much. It shows that the content of heavy metals in sediments after the industrial revolution has not changed greatly. There is a certain degree of pollution in the areas investigated in the East China Sea, so the heavy metal contents which have not changed greatly before the industrial revolution can be classified as the ideal background value without pollution. 3, through the detection of surface samples of many coastal stations, and compared with the obtained background value. The pollution of heavy metals along the coast of the East China Sea and the Yellow Sea is obtained. It can be seen that the total heavy metal content increases from offshore to inshore. With the influence of hydrology and other environmental factors in the sea area, the effect of heavy metal pollution is shown to be local, and indirectly reflects the anthropogenic effect of heavy metal pollution.
【学位授予单位】：青岛科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：X55

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