乌鲁木齐市郊安宁渠区农田土壤重金属污染现状调查与分析

发布时间：2018-05-08 10:50

本文选题：蔬菜区土壤 + 重金属污染　；参考：《新疆大学》2017年硕士论文

【摘要】：土壤作为生态系统的基本组分,在社会环境中也占据着必不可少的地位,与人类的生产和生活息息相关。土壤系统也能够为日常的农业产业活动提供基本保障。对乌鲁木齐市北郊的安宁渠区农田土壤重金属含量进行分析,调查Cu、Zn、Cd、Cr、Ni、Pb、Hg、As 8种元素的含量,并对研究区土壤中的重金属浓度的空间分布给予分析,并采用土壤环境质量二级标准(pH7.5)以及新疆土壤元素背景值为评价标准,对安宁渠区土壤重金属的污染现状给予评估,研究结果:(1)与国家土壤的环境质量二级标准值相比,研究区农田土壤8种重金属中,只有As和Cd含量大于该限值,且超标率为6%和1%;与新疆土壤背景值相比,除As以外,其他七种元素的含量高于背景值1.5倍左右,8种重金属元素都有超标情况,超标率范围为60%-99%;累积趋势较显著,表明研究区内存在外界来源输入,且这8种重金属在土壤中已存在一定的富积。(2)对安宁渠区8种金属元素做主成分分析,8种重金属元素的来源可分为三类,Zn、Cu、Ni为一类,三种元素的距离较近,元素之间的同源性较强;Hg、As为一类;Pb和Cd为一类,两两元素之间距离较近,同源性较强。对研究区内四个乡镇做相关性分析,结论与上述相似。(3)研究区中As显示出了比较明显的空间范围内的自相关关系;Cu、Ni、Cr、Cd块基比的值大于75%,在空间尺度范围内属于弱相关关系,受人为影响较大。Zn、Pb和Hg元素在空间尺度范围内属于中等相关关系,主要受人为因素和土壤自然因素影响。(4)研究区土壤中,Cu、Zn、Ni和Cr元素的分布状态相似,含量高的点位均分布在工业商业混合区附近和村落集中区域,含量低的点位分布在远离村镇的蔬菜集中种植区。Pb和Cd分布状态相似,含量高的点位多分布在蔬菜集中种植的区域和工厂近旁。Hg和As在四十户乡和青格达湖乡含量分布较大或由污水灌溉导致。(5)安宁渠区农田土壤中8种重金属的单项污染指数顺序为HgCdZnNiCuCrPbAs,Hg的单项污染指数均值是4.68,已经是重度污染;As还处于清洁水平;其余6种元素均处于轻度污染。(6)研究区土壤重金属的综合污染指数平均值为3.70,整体属于重度污染。研究区四个乡镇,六十户乡处于轻微污染等级,青格达湖乡、四十户乡和安宁渠镇为重度污染等级;(7)安宁渠区农田土壤中8种重金属单项潜在生态风险指数均值由大到小排列为:HgCdAsNiCuPbCrZn,Cd处于中度生态危害,Hg处于很强生态危害,其余6种元素为轻微生态危害,Hg对研究区生态风险贡献率最高。研究区综合生态风险指数RI均值为301.66,研究区土壤整体属于强生态危害。
[Abstract]:As a basic component of ecosystem, soil also occupies an indispensable position in social environment, which is closely related to human production and life. Soil system can also provide basic guarantee for daily agricultural industrial activities. The contents of heavy metals in farmland soil of Anning canal area in the northern suburb of Urumqi were analyzed, and the contents of 8 elements in the soil of Cuznznzhupeng, NibPbHgAs were investigated, and the spatial distribution of heavy metal concentrations in the soil of the study area was analyzed. The soil environmental quality secondary standard (pH 7.5) and the background value of soil elements in Xinjiang were used as the evaluation criteria to evaluate the status of heavy metal pollution in the Anning canal area. The results of the study were compared with the national soil environmental quality secondary standard value. Of the 8 heavy metals in farmland soil of the study area, only the contents of as and CD are higher than the limit, and the rate of exceeding the standard is 6% and 1% respectively, compared with the soil background value of Xinjiang, the contents of as and CD are higher than that of the limit, except for as. The content of the other seven elements was 1.5 times higher than the background value. All of the eight heavy metal elements were in excess of the standard, and the excess rate was in the range of 60-99.The cumulative trend was significant, indicating the existence of external source input in the study area. Analysis of the principal component of 8 kinds of metal elements in Anning canal area. The source of the eight heavy metals can be divided into three types of zinc-Cu-ni-Ni, and the distance of the three elements is relatively close, and there is a certain accumulation of the eight heavy metals in the soil. There is a strong homology between the elements. HgAs belong to a class of Pb and CD, and the distance between the two elements is close and the homology is strong. The correlation analysis of four villages and towns in the study area shows that as in the study area shows obvious autocorrelation relation in spatial range. The value of the ratio of block to base is larger than 75, and it belongs to weak correlation in spatial scale. The distribution of Cu, Zn, Zn, Ni and Cr in the soil of the study area was similar, which was mainly affected by human factors and natural factors of soil, and the distribution of Cu, Zn, Zn, Pb and Hg was similar in the range of spatial scale, and the distribution of Cu, Zn, Zn, Ni and Cr in the soil of the study area was similar. The high content points were distributed near the industrial and commercial mixed areas and the village concentration areas, and the low content points were distributed in the vegetable concentrated planting areas far from the villages and towns. The distribution of Pb and CD in the vegetable concentrated planting areas far away from the villages and towns was similar, and the distribution of CD and Pb was similar. The high content points are mostly distributed in the vegetable planting area and near the factory side. Hg and as in Xihu Township and Qinggeda Lake Township, or the single item of 8 heavy metals in farmland soil of Anning canal area caused by sewage irrigation. The average value of single pollution index in the order of HgCdZnNiCuCrPbAsHG is 4.68, which is serious pollution and as is still in clean level. The average comprehensive pollution index of soil heavy metals in the study area is 3.70, which belongs to severe pollution as a whole. In the study area, four villages and towns, sixty townships were in a mild pollution grade, and Qinggeda Lake Township, The average value of the individual potential ecological risk index of 8 heavy metals in farmland soil in Anning canal area ranged from large to small, and the average value was: 1. HgCdAsNiCuPbCrZnOCD was a moderate ecological hazard and Hg was a very strong ecological hazard. The other six elements were slight ecological hazard and Hg had the highest contribution rate to ecological risk in the study area. The average value of comprehensive ecological risk index (RI) was 301.66, and the whole soil in the study area was a strong ecological hazard.
【学位授予单位】：新疆大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X53

【参考文献】