KMS XINJIANG INSTITUTE OF ECOLOGY AND GEOGRAPHY，CAS
| 元素地球化学记录的博斯腾湖地区环境演变及影响因素研究 | |
| 蒲佳 | |
| Subtype | 硕士 |
| Thesis Advisor | 吉力力·阿不都外力 |
| 2018-06-01 | |
| Degree Grantor | 中国科学院大学 |
| Place of Conferral | 新疆乌鲁木齐 |
| Degree Discipline | 理学硕士 |
| Keyword | 元素地球化学 湖泊沉积 环境演变 风险评价 博斯腾湖 Element Geochemistry Lake Sediment Environment Evolution Risk Assessment Bosten Lake |
| Abstract | 元素能在地球表层大气、水、土壤等各种环境介质中进行迁移转化，最终汇集于湖泊中，经过长年累月的沉积作用而形成湖泊沉积物。湖泊沉积物作为湖泊-流域物质的“汇”，作为一种良好信息载体，被广泛应用于重建气候以及湖泊环境特征等研究。湖泊沉积物中各元素来自于湖泊流域内岩石和土壤风化物、人类活动排放物以及大气沉降物等，其地球化学特征能反应不同时期流域环境演化（气候、水文）的特征和人类活动的强度，是研究人类活动和气候变化对区域环境变化的贡献的重要手段。本文选取干旱区博斯腾湖为对象，利用数理统计方法、经典地统计学方法、半方差函数模型、标准化方法等建立了博斯腾湖流域的重金属元素地球化学基线值；通过有序聚类分析、地球化学校正、 Nemerow 综合污染指数法分析了沉积物元素地球化学特征，揭示了近百年来博斯腾湖流域元素地球化学的演变历史，反映气候变化和人类活动的影响，丰富天山湖泊生态环境数据库，为湖泊生态环境保护提供科学参考。本文已经取得的研究结果如下：（1）将测定博斯腾湖流域表土元素的含量与新疆土壤背景值相比，结果表明重金属元素 Cr、 Cd、 Hg 平均含量略高于背景值，其余的平均含量均低于背景值。除了 Al为弱变异外，其他 13 种元素均为中等变异程度。大多数重金属元素集中分布在农田、交通干线、城镇附近以及河流沿岸等地方。（2）本文结合统计学方法和地统计学方法对表土元素空间分布的影响因素进行分析， Fe、 Mn、 V、 Cr、 Co、 Zn、 As 受结构性因素控制，并且其空间自相关性良好。 Cu、 Cd、 Pb 变程较小，仅在小范围内存在空间相关性，说明整体结构还在，受区域随机因素（农业灌溉、交通、工业生产）影响较大。（3） 地球化学基线作为区分自然环境和人为活动的重要参照，本文选取标准化方法并以 Fe 为标准元素， 建立 Mn、 V、 Zn、 Cr 等 11 种重金属元素地球化学基线值，除了 Cd、 Hg 之外，其余均小于新疆土壤背景值。建立的 11 种重金属元素的地球化学基线值作为该流域的背景值，以反映该区域的元素地球化学特征及重金属污染情况。（4）采用地球化学校正、 有序聚类分析方法， 结合粒度、有机碳等指标分析，博斯腾湖近 150 年来的环境演变过程以 1950 年为界限划分为两个主要阶段。I 阶段：对应岩芯 32～41 cm 段，时间为 1868 年～1950 年。 该阶段反映在经济发展比较落后的时期，人为来源的流域重金属汇入量少，气候变化（气温、降水）是影响流域环境演化的主导因素。 II 阶段：对应岩芯 1～37 cm段，时间为 1950～2014 年，随着焉耆盆地的大开发的进行，流域内工农业快速发展，导致 P、 Pb、Cd、 As 等元素明显富集，表明受人类活动影响为主。（5）采用 Nemerow 综合污染指数法和 Hankson 潜在生态风险评价法对重金属进行风险评价。 Nemerow 法的结果显示，湖泊岩芯沉积物仅 Cd 元素的 Pi值高达 2.67，综合 P 值为 1.99，存在轻微污染，其余元素在警戒线内。Hankson 法结果显示 Cd 的 Eir 值高达 81.0， 存在轻微风险； 综合 RI 值高达107.08，存在轻微风险。总体来看，博斯腾湖的重金属污染程度较低， 归因于该流域工农业生产等人类活动的影响程度小，经济欠发达。 |
| Other Abstract | Element exist and migrate in the atmosphere, water, soil and other environmentalMedium, eventually converge in lake sediment. As the "sink" of lake - basin, lakesediment is a kind of good information carrier, widely applied to the research ofreconstruction of the climate change and lake environment characteristics. Eachelement of Lake sediments originates from weathering rocks and soil in the lake basin,emissions from human activities, atmospheric fallout, and etc. Its geochemicalcharacteristics suggest the environmental evolution (climate, hydrological features) andthe intensity of human activities in different periods, which is the important means inthe study of the contribution of climate change and anthropogenic activities on regionalenvironment.This article will select Bosten Lake as the object, through methods of mathematicalstatistics and geostatistics, the semivariance model, the standardized methods, establishgeochemical baseline values of heavy metal element in Bosten Lake basin; Through anorderly clustering analysis, geochemical correction, and Nemerow method, analyze thegeochemical characteristics of element in the sediment, reveal the history of evolutioncharacters of heavy metals over past century, These will abound the data volume oflakes in Tianshan mountain and provide scientific reference for the lake ecologicalenvironment protection. This article has acquired the results as follows:(1) compared the content of element in topsoil with the background values inxinjiang, Cr, Cd, Hg is slightly higher than the background value on average, the otherkinds of elements are lower. In addition to Al in weak variation, the other 13 kinds ofelements are in medium degree of variation. Most elements of high content appeared inthe farmland, the traffic trunk lines, and river near the town.(2) Through methods of mathmatical statistics and geostatistics, this articleanalyze the influence factors of the spatial distribution of element in topsoil. Fe, Mn, V,Cr, Co, Zn, As are greatly influenced by structural factors with good spatialselfcorrelation and Cu, Cd, Pb ,Hg has the spatial correlation only in a small scale,which shows that the spatial structure is still there, affected by regional random factors( agricultural irrigation, transportation, industrial production ).(3) The geochemical baseline is regarded as an important reference to distinguishbetween the natural evolution and human activities. This article will selectstandardization method and establish geochemical baseline values of Mn, V, Zn, Cr, Co,Ni, Cu, As, Cd, Pb, Hg. Except that Cd, Hg, others are slightly larger than backgroundvalue in Xinjiang, determining the baseline values of heavy metals as background value,more truthly reflecting geochemical characteristics of region and the status of heavymetal pollution.(4) Through the methods of geochemistry correction and the orderly clusteranalysis, combining with the characteristics of grain size and organic carbon, this articledivided the evolution history of nearly 150 years into two stages at 1950 a as theboundary. Stage I: about 32 ~ 41 cm, to the time of 1868 ~ 1950 a, with economicdevelopment in low speed and a little anthropogenic heavy metals import, climatechange( air temperature, precipitation) is the dominant factor affecting theenvironmental evolution. Stage II: about 1 ~ 37 cm, period of 1950 ~ 2014, along withthe great development of Yanqi basin, agriculture and industry rapidly developing, ledto the input anthropogenic heavy metal increaseing gradually. Enrichment coefficientsof P, As, Pb, Cd, As significantly rising show its considerably affected by humanactivities.(6) Based on the methods of Nemerow and Hankson, this article evaluate thepotential ecological risk of heavy metal in Bosten Lake basin. The result of Nemerowsmethod suggested that the Pi value of Cd is up to 2.67, with a value of 1.99 of total Pin core sediment of lake, suggesting slightly polluted degree, the remaining within thered line. Hankson method results show that the Eir value of Cd is 81.0, as well as thecomprehensive RI value is 107.8, at the slight potential ecological risk in core sediment.In general, the pollution of heavy metal is at the low level, because of little impact ofhuman activities such as industrial and agricultural production, economicunderdevelopment. |
| Subject Area | 自然地理学 |
| Language | 中文 |
| Document Type | 学位论文 |
| Identifier | http://ir.xjlas.org/handle/365004/14981 |
| Collection | 研究系统_荒漠环境研究室 |
| Affiliation | 中国科学院新疆生态与地理研究所 |
| First Author Affilication | 中国科学院新疆生态与地理研究所 |
| Recommended Citation GB/T 7714 | 蒲佳. 元素地球化学记录的博斯腾湖地区环境演变及影响因素研究[D]. 新疆乌鲁木齐. 中国科学院大学,2018. |
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