南淝河水—沉积物重金属分布特征及环境评价

发布时间：2018-11-16 20:29

【摘要】：本文为系统研究南淝河的重金属污染状况,分别于丰水期、平水期和枯水期对南淝河水和沉积物进行采样,分析了南淝河水和沉积物重金属的时空分布特征。主要对水和沉积物等环境介质的重金属总量和赋存形态特征进行了讨论,并依据单因子水质标识指数评价法和改进后的模糊综合污染指数评价法对南淝河水中重金属进行了污染评价,依据地累积指数法和潜在生态风险指数法对南淝河沉积物重金属总量进行了污染评价,结合P值风险评价法和风险评估指数法对南淝河沉积物重金属赋存形态进行了风险评估,依据数学方法结合SPSS软件,对南淝河重金属进行了污染溯源。研究结果表明:(1)水中各元素在不同水文时期含量变化情况基本一致,重金属污染程度表现为丰水期平水期枯水期。(2)南淝河沉积物中各重金属含量差异较大,同一元素在不同水文时期的含量差异较小。五种元素均存在超标情况,Cd超标情况最严重。各元素均以残渣态为主要赋存形态,从残渣态所占比例上看,As元素的活性最小,Cd元素活性最大。(3)单因子水质标识指数评价法和改进后的模糊综合评价法评价结果显示Cd污染程度最高,Pb的污染程度仅次于Cd。地累积指数评价结果显示各采样点污染程度在清洁到轻度污染之间,五种元素中Cd元素污染程度最高。潜在生态风险指数评价结果显示各采样点均属于中度生态危害水平,五种元素中仅Cd元素风险较大。P值风险评价和风险评估指数法评价结果均显示仅Cd元素风险水平较高。因此Cd是五种重金属元素中的主要污染因子。(4)结合水和沉积物的重金属主成分分析结果可知,南淝河的主要重金属污染来源是流域内的农药化肥、机械制造和电镀行业的废水以及河道的行船。
[Abstract]:In order to study the pollution of heavy metals in Nanfeihe River, the heavy metals in Nanfeihe River and sediment were sampled in the periods of high water, normal water and dry water, and the temporal and spatial distribution characteristics of heavy metals in Nanfeihe river and sediment were analyzed. The contents and speciation characteristics of heavy metals in environmental media such as water and sediment are discussed. The pollution of heavy metals in Nanfeihe River was evaluated according to the single factor water quality index evaluation method and the improved fuzzy comprehensive pollution index evaluation method. Based on the soil accumulation index method and the potential ecological risk index method, the pollution assessment of heavy metals in the sediments of Nanfeihe River was carried out, and the occurrence forms of heavy metals in the sediments of the Nanfeihe River were evaluated by combining the P value risk assessment method and the risk assessment index method. Based on the mathematical method and SPSS software, the pollution source of heavy metals in Nanfeihe River was traced. The results show that: (1) the variation of the contents of elements in water is basically the same in different hydrological periods, and the pollution degree of heavy metals is the dry season in the high water period. (2) the content of heavy metals in the sediments of Nanfeihe River is different greatly. The content of the same element in different hydrological periods is less different. All of the five elements are in excess of the standard, and Cd is the most serious. The residual state was the main occurrence form of each element, and the activity of As element was the lowest in the proportion of residual state. (3) single factor water quality index evaluation method and improved fuzzy comprehensive evaluation method showed that Cd pollution degree was the highest, and Pb pollution degree was second only to Cd.. The result of ground accumulation index evaluation showed that the pollution degree of each sampling point was between clean and light pollution, and the pollution degree of Cd element was the highest among the five elements. The results of potential ecological risk index evaluation showed that all the sampling points belonged to moderate ecological hazard level, and only Cd elements of the five elements were at greater risk. P value risk assessment and risk assessment index method showed that only Cd element risk level was higher. Therefore, Cd is the main pollution factor of five heavy metal elements. (4) combined with the analysis of heavy metals in water and sediment, the main heavy metal pollution source of Nanfeihe River is pesticide and chemical fertilizer in the basin. Machinery manufacturing and electroplating industry waste water and river boat.
【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X522;X824

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