浦阳江流域土壤和底泥重金属污染研究

发布时间：2019-06-12 19:17

【摘要】：随着我国城市化和工业化的快速发展,河流受人类活动的影响越来越频繁,河流重金属污染现象也日趋严重。浦江县作为我国最大的水晶玻璃产业集聚区,由于不合理的发展,对浦阳江流域造成了巨大的污染,2014年浦江县对浦阳江流域(浦江县城区段)开展了底泥清淤,以期恢复河道的正常功能和生态环境。本文为了反映浦阳江流域(浦江县城区段)清淤前后底泥和河岸带土壤的重金属含量情况,采集了50份浦阳江流域六条河流的河岸带土壤和底泥样本,生态清淤站的64份样本,选取了As、Cr、Ni、Cu、Zn、Pb等六种元素作为评价元素,统计其含量特征,进行空间分布和相关性分析,进而从内梅罗指数法,地累积指数法、潜在生态危害指数法三种评价方法对研究区各条河流土壤和底泥清淤前后污染情况进行全面评价;同时通过对浦江县的水晶废渣的重金属研究,判断其是否存在重金属危害,以及是否与浦阳江流域的土壤和底泥中的重金属含量具有相关性,来解析污染源,最后针对浦阳江流域土壤和底泥中存在的重金属污染,提出防治对策。研究结果表明:(1)As和Cr为水晶废渣中的两种主要重金属,其中As具有极强生态危害,为主要污染物,需要对水晶废渣进行统一回收再利用。(2)浦阳江流域底泥未清淤前,各个断面的底泥重金属含量较一致,且重金属含量都较高,As为富集程度最高的金属。清淤后,浦阳江流域土壤和底泥重金属依然有一定程度的重金属富集,但明显低于清淤前的底泥重金属含量,清淤取得了一定的效果,但清淤效果不一致;土壤和底泥重金属富集程度较一致,As为底泥和土壤中富集程度最高的重金属,受人为影响较大。(3)黄龙溪和西溪分别为为河岸带土壤重金属和底泥重金属程度富集最高的河流,西溪底泥清淤效果不佳,需要增加疏浚深度,尤其是工业园区和各河河口处;可以对黄龙溪的河岸带土壤种植富砷植物,降低As的含量。浦阳江和里坞溪为整个流域中重金属富集程度最低的河流,整体上清淤效果较好。(4)除Ni以外,浦阳江流域的土壤和底泥重金属普遍高于金衢盆地的背景值,As和Pb含量高的区域主要集中在两个工业园区,Cr和Zn含量较高的区域主要集中在河口处;清淤前浦阳江流域底泥重金属元素来源具有多样性的特点,表现出一定的综合性复合污染;底泥和土壤中的As与Pb都具有相关性,可能来自同一污染源。(5)清淤后浦阳江流域的底泥污染程度降低,生态危害降低,浦阳江流域底泥和河岸带土壤污染最严重的河流分别为西溪和黄龙溪,As为浦阳江流域土壤和底泥最主要的污染元素。
[Abstract]:With the rapid development of urbanization and industrialization in China, rivers are more and more frequently affected by human activities, and the phenomenon of heavy metal pollution in rivers is becoming more and more serious. Pujiang County, as the largest crystal glass industry agglomeration area in China, has caused great pollution to Puyang River Basin due to unreasonable development. In 2014, Pujiang County carried out sediment desilting in Puyang River Basin (urban section of Pujiang County) in order to restore the normal function and ecological environment of the river. In order to reflect the content of heavy metals in sediment and riparian soil before and after silting in Puyang River Basin (urban section of Pujiang County), 50 samples of soil and sediment from six rivers in Puyang River Basin and 64 samples from ecological siltation station were collected. Six elements, such as As,Cr,Ni,Cu,Zn,Pb, were selected as evaluation elements, their content characteristics were counted, and spatial distribution and correlation analysis were carried out. Then the pollution of soil and sediment of each river in the study area was comprehensively evaluated from three evaluation methods: Neimero index method, land accumulation index method and potential ecological hazard index method. At the same time, through the study of heavy metals in crystal waste residue in Pujiang County, whether there is heavy metal harm or not, and whether it is related to the content of heavy metals in soil and sediment of Puyang River Basin, the pollution sources are analyzed. Finally, the prevention and control countermeasures are put forward in view of the heavy metal pollution existing in soil and sediment of Puyang River Basin. The results show that: (1) As and Cr are two main heavy metals in crystal waste residue, among which As has strong ecological harm and is the main pollutant. (2) before the sediment of Puyang River Basin is cleared, the content of heavy metals in sediment of each section is the same, and the content of heavy metals is high, and As is the metal with the highest enrichment degree. After silting, the heavy metals in soil and sediment of Puyang River Basin are still enriched to a certain extent, but it is obviously lower than the content of heavy metals in sediment before desilting, and some results have been obtained, but the effect of desilting is not consistent. The enrichment degree of heavy metals in soil and sediment is the same. As is the most enriched heavy metal in sediment and soil, which is greatly affected by artificial. (3) Huanglong River and Xixi River are the rivers with the highest concentration of heavy metals in soil and sediment in riparian zone, respectively. The effect of sediment removal in Xixi River is not good, so it is necessary to increase the dredging depth, especially at the industrial park and the estuary of each river. Arsenic-rich plants can be planted in the riparian soil of Huanglong River to reduce the content of As. Puyang River and Liwu River are the rivers with the lowest concentration of heavy metals in the whole basin, and the effect of desilting is better. (4) except Ni, the heavy metals in soil and sediment of Puyang River Basin are generally higher than the background value of Jinqu Basin, the areas with high As and Pb contents are mainly concentrated in two industrial parks, and the areas with high Cr and Zn contents are mainly concentrated in the estuary. Before silting, the source of heavy metal elements in sediment of Puyang River Basin has the characteristics of diversity, showing a certain degree of comprehensive compound pollution. There is a correlation between As and Pb in sediment and soil, which may come from the same pollution source. (5) after silting, the degree of sediment pollution and ecological harm in Puyang River Basin are decreased. The rivers with the most serious soil pollution in Puyang River Basin and riparian zone are Xixi and Huanglong River, respectively. As is the most important pollution element in soil and sediment in Puyang River Basin.
【学位授予单位】：浙江农林大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X53;X52

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