重金属元素在互花米草盐沼湿地的富集、迁移及循环规律

发布时间：2018-06-12 21:38

本文选题：互花米草 + 重金属元素　；参考：《南京大学》2015年硕士论文

【摘要】：湿地是自然界中最具生产力的生态系统,其内部的元素循环过程异常活跃、复杂。为了研究互花米草盐沼湿地中重金属元素的循环过程,本文选择苏北王港盐沼湿地作为研究区域,以湿地内部的植物—互花米草以及其生长的周围土壤为研究对象。本文采集的样品有:2012年8月至2013年6月(每两月一次,共6次)表层沉积物(光滩沉积物和互花米草滩沉积物)、2012.8柱状沉积物(WG1、WG2和WG3位于互花米草滩,WG4位于光滩)、2012.8采集3个植物样方(WG1、WG2和WG3),然后对样品进行粒度、生物量、重金属元素Cr、Pb、Cu、Zn和Mn的含量等参数的测定,结合数据的分析、统计以及文献综合,试图计算出互花米草对重金属元素Cr、Pb、Cu、Zn和Mn的年吸收量、年归还量、年存留量及富集系数、迁移系数、吸收系数、循环系数与周转期。通过分析本文得出的主要结论如下:(1)土壤是重金属元素最主要的贮存库,其储量远远大于互花米草体内重金属元素的储存量,互花米草根系中重金属元素的储存量最高,其次为叶,茎中重金属元素的储存量最低。土壤中5种重金属元素储量的先后顺序为MnZnCrPbCu。(2)在王港互花米草盐沼湿地中,单位面积的互花米草地上部分固定Cr、Pb、Cu、Zn 和 Mn 的数量分别为 5.96 mg·m-2·a-1、16.31 mg·m2·a-1、6.78 mg·m-2·a-1、32.43 mg·m-2·a-1 和 319.59 mg·m-2·a-1。(3)互花米草体内元素的储量决定于生物量和重金属元素的含量两个因素,互花米草茎、叶和枯枝落叶中元素Cr、Pb、Cu和Zn的储量与元素的含量呈极显著相关性,茎中元素Cr的储量与生物量也呈极显著相关关系,叶中元素Pb的储量与生物量呈显著相关关系,叶和枯枝落叶中元素Mn的储量与元素含量呈极显著相关关系,与生物量相关性较差,茎中元素Mn的储量与元素含量相关性比较差,与生物量呈极显著相关关系。(4)互花米草根系对重金属的富集能力强于地上部分;地上部分对5种重金属富集能力的强弱顺序为PbMnZnCuCr,根系对5种重金属富集能力的强弱顺序表现为CuZnPbMnCr。(5)互花米草对重金属元素的迁移能力的大小排序为MnCrPbZnCu,迁移能力不仅由植物本身的特性决定,而且与重金属在土壤中的活性或形态有关。(6)互花米草根系对重金属元素Cr、Pb、Cu、Zn和Mn年吸收量、年归还量与年存留量均为最大,其次为叶,茎最小;互花米草一年内所吸收的重金属元素中约有45.7%归还到周围环境中,剩余的54.2%存留在互花米草体内。(7)互花米草对5种重金属元素吸收系数大小排序为ZnCuPbMnCr。互花米草对元素Zn的吸收系数最大,其次为元素Cu,说明土壤中的Zn和Cu相对其它元素更容易进入互花米草体内,可能是这两种元素在土壤中多以水溶态或者离子态存在,也可能是由植物本身的特性决定。(8)互花米草对5种重金属元素的循环系数的大小排序为Cu≈ZnPbMnCr,说明互花米草体内元素Cu和Zn的归还比例最高,为46.8%,元素Cr的归还比例最低,为44.8%,相对于其它元素,互花米草将吸收的元素Cr较多地储存在体内。因此互花米草可以修复Cr污染比较严重的土壤。(9)互花米草体内元素Cr、Pb、Cu、Zn和Mn的周转期分别是2.3年、2.8年、1.7年、2.5年和2.7年,周转期长短顺序为PbMnZnCrCu,元素Pb的周转期最长,流动性最差。
[Abstract]:Wetland is the most productive ecosystem in nature, its internal elements cycle process is very active and complex. In order to study the cycle process of heavy metal elements in the salingrass marsh wetland, this paper chooses the salt marsh wetland in North Jiangsu as the research area, with the plants in the wetland and its growing surrounding soil. The samples were collected from August 2012 to June 2013 (6 times per month, 6 times), 2012.8 columnar sediments (WG1, WG2 and WG3 in interflower rice beach, WG4 in the shoal), and 2012.8 samples of plants (WG1, WG2 and WG3), followed by grain size. The content of heavy metals, Cr, Pb, Cu, Zn and Mn were measured, combined with data analysis, statistics and literature synthesis, trying to calculate the annual absorption, annual return, annual retention, accumulation coefficient, migration coefficient, absorption coefficient, cycle coefficient and turnover period of the heavy metal elements Cr, Pb, Cu, Zn and Mn. The main conclusions are as follows: (1) the soil is the most important storage reservoir of heavy metals, its reserves are far greater than the storage of heavy metals in the plants of M. alterniflora. The storage of heavy metals in the root system of interflower rice is the highest, followed by the leaves and the storage of heavy metals in the stems is the lowest. The reserves of the 5 heavy metal elements in the soil are successively. The order of MnZnCrPbCu. (2) was in the wetland of M. alterniflora salt marsh in Wang Hong Kong. The amount of Cr, Pb, Cu, Zn and Mn in the upper part of the ground part of the plant was 5.96 mg. M-2. A-1,16.31 mg. M2. The content of the elements Cr, Pb, Cu and Zn in the stem, leaf and litter of the leaves of alterniflora was significantly correlated with the content of elements. The reserves of Cr in the stem were also significantly related to the biomass, and the reserve of the element Pb in the leaves was significantly related to the biomass of the leaves and the storage of the element Mn in the leaves and litter leaves. There was a very significant correlation between the content and the content of the elements, and the correlation of the biomass of the element Mn in the stem was poor, and the correlation of the element content was very poor. (4) the enrichment ability of the root system of interflower rice was stronger than the upper part of the earth, and the order of the enrichment of the 5 kinds of heavy metals in the upper part of the earth's upper part was PbMnZnCuC. R, the sequence of strong and weak roots to the enrichment ability of 5 kinds of heavy metals is CuZnPbMnCr. (5) the order of the migration ability of the heavy metal elements is MnCrPbZnCu. The migration ability is determined not only by the characteristics of the plant itself, but also with the activity and morphology of heavy metals in the soil. (6) the interflower rice root system is Cr, Pb, Cu. In Zn and Mn years, the annual return and the annual retention were the largest, followed by leaves and the smallest stems; about 45.7% of the heavy metals absorbed within one year of alterniflora returned to the surrounding environment, and the remaining 54.2% remained in the body of alterniflora. (7) the size of the absorption coefficient of 5 heavy metal elements was ZnCuPbMnCr. interflower rice. The absorption coefficient of the element Zn is the largest, followed by the element Cu, indicating that the Zn and Cu in the soil are more easily entered in the body of the rice grass than the other elements. It may be that these two elements are mostly in the water soluble or ionic state in the soil, and may be determined by the characteristics of the plant itself. (8) the cycle coefficient of 5 heavy metal elements of the rice grass. The order of the size is Cu ZnPbMnCr, indicating that the proportion of the elements Cu and Zn is the highest, and the proportion of the element Cr is the lowest, and the proportion of the element Cr is the lowest, which is 44.8%. The M. alterniflora will absorb more elements Cr in the body. Therefore, the rice grass can repair the serious soil contaminated by Cr. (9) the body of alterniflora. The turnover period of elements Cr, Pb, Cu, Zn and Mn is 2.3 years, 2.8 years, 1.7 years, 2.5 years and 2.7 years. The sequence of turnover period is PbMnZnCrCu, and the turnover period of element Pb is the longest and the fluidity is the worst.
【学位授予单位】：南京大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X142

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