艾比湖流域沉积物元素地球化学特征及其揭示的环境信息
文献类型：学位论文
| 作者 | 丁之勇 |
| 答辩日期 | 2017-05-01 |
| 文献子类 | 硕士 |
| 授予单位 | 中国科学院大学 |
| 授予地点 | 新疆乌鲁木齐 |
| 导师 | 吉力力·阿不都外力 |
| 关键词 | 艾比湖流域 沉积物 元素地球化学 环境演化历史 潜在生态风险 Ebinur Lake Basin Sediments Element Geochemical Environment Evolution History Potential Ecological Risk |
| 学位专业 | 理学硕士 |
| 英文摘要 | Soil is an important basis material for the survival of plants and animals on the earth. It is also an important resource for the development of human production. Element as an important component of soil, its natural content depends on the natural factors such as parent material, soil formation, topography, regional climate, biology and other natural factors. Lake sediments are faithful records of the natural environment evolution (climate, hydrology) and information of human activities in different periods. The elements in the soil of the river basin are imported into the lake under the action of erosion and transportation, and are deposited on the bottom of the lake. The changes in the records of its material sources, the degree of geochemical weathering and erosion, the intensity of human activities, regional climate change and the history of lake geochemical evolution are important indicators of regional environmental change. Therefore, in this study, physicochemical proxies (focus on elements) of sediment core in Ebinur Lake are studied, statistical analysis, the semi-variance function model, IDW method and potential ecological risk index method are using to analyze the elements spatial heterogeneity and influence factors of elements in topsoil are also analyzed; using enrichment factor correction method, sequential clustering analysis method to analyze the geochemical characteristics and the environment evolution history, heavy metal pollution history of watershed are also analyzed. This study, in order to give basic scientific guides for the coordinated development of the regional ecological environment and human society, a basic information of the regional environmental change and its response to human activities in Ebinur Lake basin. The main conclusions are listed as follows:（1） Descriptive statistics of element concentrations in topsoil showed: The average contents of Ba, Mn, V, Pb, Cr, Co, Ni, Cu in the topsoil of Ebinur Lake were lower than those of Xinjiang soil background value, while other elements of the average value are higher. The spatial distribution of the contents of elements Ca, Mg, Na, Sr, Ni and Cd shows the most obvious difference from medium to strong variability, while the other elements shows weak variability. The high value area of most elements is mainly located in the fields of farmland, traffic trunk, river and urban residential areas, which indicates that the distribution of surface elements in the study area is affected by human activities and local environment.（2） The environmental proxies of particle size, total organic carbon and elements in Ebinur Lake shows that there are two obvious differences at the deep of 23cm (1960 AD):the content of each environmental proxy was lower and changed small before 1960; after 1960, the content suddenly increased and fluctuated significantly, especially heavy metals Co, Cr, Cu, Ni, Pb, V, Zn and so on.（3） The influence factors of elements in topsoil were analyzed by classical statistical and geostatistics analysis, which shows that elements Al, Fe, K, Ti, Ba, Be, Mn, V,Ti, Ba and so on have a medium to strong spatial autocorrelation and the spatial structure of the element P and the heavy metal elements Zn, Pb, Ni and Cu are more complicated due to random factors such as tillage fertilization, transportation, industrial and agricultural production. Elements Ca、 Sr、 Mg have a strong active geochemical characteristic, in addition to under the influence of regional soil parent material, and easily influenced by local factors lead to complicated spatial structure. Cd is a heavy metal element, however, it is divided into the same class with Ca, Sr and other activity chemical elements, which may be affected by the man-made industrial and agricultural activities, traffic and other anthropogenic resulting in large differences of the distribution and strong spatial variability in the study area, then there is no spatial autocorrelation at the sampling scale. Element Na shows a poor spatial structure due to the regional natural environment changes and the impact of man-made farming.（4） Elements in sediment core are divided into three assemblage: Fe, Mn, V, Ni, Li,Cr, K, Al, Co, P, Ti, Be, Pb, Cu, Ba and Zn are mainly derived from watershed terrestrial debris, and the content of those elements are mainly affected by the watershed erosion intensity. Among them, the changes of heavy metals Co, Cr, Cu, Ni, Pb, V, Zn and nutrient P were nearly different in the past 150 years. The ordered specimen cluster analysis method was applied to study the lake environmental changes base on the enrichment factors of heavy metals and P. The results show that the environmental evolution history nearly 150 years can divide into two distinct stages taking 23 cm (1960) as the boundary in the Ebinur Lake basin:Stage I. From 1875 to 1960 AD, at this stage the level of social development of the basin is low, human activities lead to less input of heavy metals, the basin environment is mainly affected by regional natural changes;Stage II. From 1960 ~ Present, with the increase of population, economic development,industrial and agricultural activities increased, especially agricultural water consumption increased, most of the heavy metal elements and P relative to the early have a more obvious increase. The second type of elements includes Mg and Na, mainly from the evaporation of salt crystals in lake water. Due to the development of oasis agriculture and the increase of irrigation water, the lake water level fluctuates violently under the influence of climate change and human activities which lead to the fluctuations Mg, Na and other elements. The third class elements include Ca and Sr, which are controlled by the weathering leaching of readily soluble elements in the watershed （5） The enrichment coefficient and the potential ecological risk assessment show that most of the heavy metal elements in the topsoil of the basin have been affected by human activities, and the enrichment of Cd is most obvious, its Eri value is up to 287.6 which means a highly potential ecological risk; followed by Ni and Cu, Ni Eri value of up to 25.7; Overall, 8 kinds of heavy metal elements in the topsoil comprehensive potential ecological risk (RI) average is 85.5 showing a slight ecological risk. And most of the high RI value areas are located in the main road, farmland and urban areas where human activities are relatively intensive. The accumulation of heavy metals in lake sediments core is lower than that in topsoil, although the accumulation of heavy metals has increased since 1960, but the total cumulative index and potential ecological risk are lower. The results showed the potential ecological risk of elements in sediment core followed the order: Ni(4.7)＞Pb(4.6)＞Cu(4.2) ＞Co(2.6)＞Cr(1.7)＝V(1.7)＞Zn(1.1), and the potential ecological risk of those heavy metals were slight. |
| 学科主题 | 自然地理学 |
| 语种 | 中文 |
| 源URL | [http://ir.xjlas.org/handle/365004/14868]  |
| 专题 | 新疆生态与地理研究所_研究系统_荒漠环境研究室 |
| 作者单位 | 中国科学院新疆生态与地理研究所 |
| 推荐引用方式 GB/T 7714 | 丁之勇. 艾比湖流域沉积物元素地球化学特征及其揭示的环境信息[D]. 新疆乌鲁木齐. 中国科学院大学. 2017. |
入库方式： OAI收割
来源：新疆生态与地理研究所
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