黄河三角洲潮间带沉积物重金属赋存形态的研究

发布时间：2018-07-26 10:08

【摘要】：随着黄河三角洲经济的快速发展,黄河三角洲潮间带地区的重金属污染情况日益严重。沉积物作为重金属污染的源与汇,是水体中重金属的主要聚集地。本文选择了一年内三个时段对具有代表性的黄河三角洲潮间带地点的沉积物进行采样,对沉积物中包括As、Cd、Cr、Cu、Ni、Pb与Zn七种重金属的赋存形态进行了提取分析,利用Hakanson潜在生态风险评价、SQGs法(沉积物质量基准风险评价法)与RAC值法(risk assessment code)、P值法(次生相与原生相分布比值法)对沉积物重金属风险进行评价,旨在为合理开发利用黄河三角洲资源,制定污染防治措施以及流域治理规划等提供科学依据。研究结果表明,黄河三角洲潮间带地区重金属总量及赋存形态随着时间的变化而变化。其中重金属总量变化趋势为重金属As与重金属Cr整体上呈现下降趋势,重金属Cd与重金属Zn整体上呈现上升趋势,重金属Cu与重金属Ni在总趋势上呈现先减小后增大的趋势,重金属Pb显示为先增大后减小的趋势。赋存形态变化趋势中重金属Cd与Pb四种赋存形态比例变化剧烈,重金属As、Cr、Cu、Ni与Zn四种赋存形态比例相对变化平稳。本文根据四种不同的重金属风险评价方法比较了七种重金属的风险程度,并指出各评价方法的优劣性。根据Hakanson潜在生态风险评价分析三个时期的各金属元素中Cd潜在风险较大,其余次之。根据沉积物质量基准法分析三个时期As、Cr、Cu、Ni、Pb均有不同程度的中度污染,而重金属Cd与Zn没有呈现污染的情况。三个时间段RAC风险评价结果为重金属Cd与Zn风险较大,Cu、As、Ni、Pb与Cr具有不同程度的轻度风险。P值方法结果显示Cd与Pb风险较大。综合分析可以得出,重金属污染现状不容乐观,尤其是重金属Cd的污染最为严重,重金属Pb、Zn的污染也不容忽视。本文对探寻黄河三角洲潮间带重金属的来源、评价污染现状、预测对生态系统的影响及河流环境保护具有重要的现实意义。
[Abstract]:With the rapid development of economy in the Yellow River Delta, heavy metal pollution in the intertidal zone of the Yellow River Delta is becoming more and more serious. As a source and sink of heavy metal pollution, sediment is the main accumulation of heavy metals in water. In this paper, three periods of the year were selected to sample the sediments in the typical intertidal zone of the Yellow River Delta, and the occurrence forms of seven heavy metals in the sediments, including Aspergillus crassifolia, NiNiPb and Zn, were extracted and analyzed. The risk of heavy metals in sediments was evaluated by using Hakanson potential ecological risk assessment and RAC value (risk assessment code) P method (ratio of secondary phase to primary phase distribution). The aim is to provide scientific basis for the rational exploitation and utilization of resources in the Yellow River Delta, the formulation of pollution prevention and control measures and the planning of river basin management. The results show that the total amount and occurrence of heavy metals in the intertidal zone of the Yellow River Delta change with time. The variation trend of heavy metal amount is as and Cr, CD and Zn as a whole, and Cu and Ni decrease first and then increase, in the total trend, the heavy metal as and Cr show a downward trend, CD and Zn as a whole show an upward trend, and the heavy metal Cu and Ni decrease first and then increase in the general trend. Heavy metal Pb showed a tendency of first increasing and then decreasing. The proportion of CD and Pb forms changed sharply in the trend of occurrence forms, and the ratio of the four forms of heavy metal AsCrCrCU / Ni and Zn changed steadily. According to four different methods of heavy metal risk assessment, this paper compares the risk degree of seven heavy metals, and points out the merits and demerits of each evaluation method. According to the Hakanson potential ecological risk assessment, CD potential risk was higher in each metal element in three periods, followed by the rest. According to the sediment quality standard method, there was moderate pollution in all three periods, but the heavy metals CD and Zn were not polluted. The results of RAC risk assessment showed that the heavy metal CD and Zn had a higher risk. The results of the method showed that the risk of CD and Pb was higher. The comprehensive analysis shows that the status of heavy metal pollution is not optimistic, especially the pollution of heavy metal CD is the most serious, and the pollution of heavy metal Pb, Zn can not be ignored. This paper is of great practical significance in exploring the sources of heavy metals in the intertidal zone of the Yellow River Delta, evaluating the present pollution situation, predicting the impact on the ecosystem and protecting the river environment.
【学位授予单位】：首都经济贸易大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X52

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