杭白菊不同产区中土壤重金属离子含量差异及污染评价

发布时间：2018-01-10 17:37

本文关键词：杭白菊不同产区中土壤重金属离子含量差异及污染评价　出处：《浙江农林大学》2016年硕士论文　论文类型：学位论文

【摘要】：随着我国工业化和城市化的快速发展,土壤受人类活动的影响越来越频繁,土壤重金属污染现在也日趋严重。在嘉兴市,杭白菊作为支柱性产业,也是我国最大的杭白菊产区,近年来,由于经济效益和环境的冲突,产区的土壤环境也遭到了不同程度的污染。本文为了反映嘉兴市杭白菊主产区内土壤重金属含量的情况,挑选了当地具有代表性的3个产区,共采集了60份产区内土壤样本,通过牛津手持式金属探测仪进行检测,并选取了Cr、Ni、Cu、Zn、Cd、Hg、Pb等7种元素作为评价元素,对其整体生产区的含量与背景值之间进行比较,统计各个采集点的含量特征,进而从内梅罗指数法,潜在生态危害指数法评价方法对研究区各采集点的污染情况进行全面评价,并判断其是否具有重金属危害。并试着去探究污染源及提出相关的防治对策。研究结果表明:(1)三个生产区的Cr、Cd、Hg、Pb整体元素含量普遍高于杭嘉湖平原背景值,Ni、Cu、Zn元素含量低于背景值。生产区中Hg的含量较背景值有明显偏高,为主要污染物,具有极强的生态危害性。(2)Hg的高含量主要集中在生产区内几个采集点,呈现出一定的点状污染,且变异系数多为强变异,即受到人类活动影响明显。在三个生产区整体种植方式差异不大的情况下,可能是由于农户个体间的种植方法差异(施用含甲基汞杀菌剂)及特殊地理环境的综合性污染所引起的。而Cd的高含量比较普遍,变异系数多为中等变异,可能是由于生产区的种植历史背景所导致的。(3)评价结果显示,Hg和Cd为主要污染物,都出现了明显的污染,其中在Cd方面,各点均为轻污染,而在Hg方面,各采集点表现出了不同程度的重污染和中污染。从单一重金属潜在生态危害指数看,Cd处于中等生态危害,Hg处于极强生态危害,其余重金属处于轻微生态危害,从多种重金属综合潜在生态危害指数来看,3个生产区都处于很强生态危害。根据结果提出建议:针对高污染点进行周边环境的检测,确定主要污染源,并对主要污染源进行分析。探究环境、施肥、施药可能对杭白菊品质的影响。为了改善当前土壤环境,建议采用杭白菊与不同作物轮作、套作和兼作的栽培模式。针对土壤中重金属污染严重的情况,可以通过植物修复如植物提取,植物稳定,植物挥发等方法调节土壤环境中的重金属含量。
[Abstract]:With the rapid development of industrialization and urbanization in China, soil is affected by human activities more and more frequently, and soil heavy metal pollution is becoming more and more serious. In Jiaxing City, Hangzhou Chrysanthemum is a pillar industry. It is also the largest chrysanthemum production area in China, in recent years, due to the conflict between economic benefits and the environment. In order to reflect the content of heavy metals in the soil of the main producing areas of Hangzhou, Jiaxing City, three representative production areas were selected. A total of 60 soil samples were collected and detected by the Oxford hand-held metal detector, and 7 elements, such as Cr-NiCU, ZnCU, CDGG, Pb and so on, were selected as evaluation elements. The content of the whole production area was compared with the background value, and the content characteristics of each collection point were counted, and then the method of Nemero index was used. The method of potential ecological hazard index was used to evaluate the pollution of each collection site in the study area. And to determine whether it is harmful to heavy metals, and try to explore the pollution sources and put forward the relevant control measures. The research results show that the three production areas of Cr-CdHG. The Pb content of the whole element is generally higher than that of the background value of Hangjia-Lake Plain. The content of Cu Cu Zn is lower than the background value. The Hg content in the production area is obviously higher than the background value and is the main pollutant. The high content of HG with extremely strong ecological hazard is mainly concentrated in several sampling sites in the production area, showing a certain point pollution, and the coefficient of variation is mostly strong variation. That is, affected by human activities obviously. In the three production areas, the overall planting patterns are not different. It may be caused by the difference of planting methods among individual farmers (using methylmercury fungicides) and the comprehensive pollution of special geographical environment, while the high content of CD is relatively common, and the coefficient of variation is mostly medium variation. The results of evaluation showed that Hg and CD were the main pollutants, and there were obvious pollution in CD, especially light pollution in CD. In terms of Hg, different levels of heavy pollution and moderate pollution were observed in the collection sites. According to the single index of potential ecological hazards of heavy metals, CD was in medium ecological hazards and Hg was in extremely strong ecological hazards. The other heavy metals were in slight ecological harm, from the comprehensive potential ecological hazard index of many heavy metals. According to the results, the following suggestions were put forward: to detect the surrounding environment, to determine the main pollution sources, to analyze the main pollution sources, to explore the environment, and to apply fertilizer to the three production areas. In order to improve the current soil environment, it is suggested to use the cultivation mode of rotation, intercropping and both cropping with different crops in order to improve the soil environment of Hangbai chrysanthemum. The heavy metal content in soil environment can be regulated by phytoremediation, such as plant extraction, plant stability and plant volatilization.
【学位授予单位】：浙江农林大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：X53;X825

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