典型地球化学景观区硒地球化学特征及生态效应

发布时间：2018-02-14 12:52

  本文关键词： 典型景观区 Se 地球化学特征 富集系数 生态效应　出处：《中国地质大学(北京)》2017年硕士论文　论文类型：学位论文

【摘要】：硒是人体和动物必需的微量元素,当人和动物硒摄入量不足或过低时,会引发缺硒病症并降低免疫力。我国是一个贫硒国家,72%地区缺硒或低硒,2/3的人口硒摄入不足。近十几年来土壤硒地球化学特征、及生态效应研究已经成为我国乃至全世界应用地球化学领域的研究热点。多目标区域地球化学调查已经圈出不少土壤硒富集区,虽然一些地区的土壤硒总量虽然较高,但真正能被植物吸收利用的硒却占土壤总硒比例一般不到5%。大量研究表明,植物中硒主要来源于土壤,硒元素以土壤-农作物-农畜产品的迁移途径影响到人体健康,因此研究土壤硒来源、活化迁移及其在土壤—作物系统中的吸收富集规律具有重要意义。本文以典型富硒景观区1:5万土地质量地球化学调查资料开展硒地球化学特征分析和研究。结果表明:(1)焦作博爱县研究区土壤中CaO、MgO等主要受北部岩石风化影响,SiO2等主要受南部黄河冲洪积物控制,Se元素呈现北高南低的特征,主要受到北部基岩风化、成土次生富集和人类活动污染影响;(2)仙桃张沟镇研究区土壤元素主要受东荆河控制,SiO2、Na2O在离河近的区域含量高,Al2O3、TFe2O3等在远离河道的区域含量较高,Se元素高背景区位于研究区中部及东南角,源自于上游恩施紫阳等地经由长江、汉水搬运沉积;(3)绵竹齐天镇研究区元素分布主要受西北部高背景以及秀水河、绵远河、石亭江及其支流冲洪积物的影响,Se元素呈西北高、东南低的分布态势。研究区小麦及水稻富硒率高,Se含量高于0.04mg/kg的样品占99.4%;土壤理化条件对作物Se的富集系数有显著影响,小麦和水稻中Se含量与根系土Se含量无显著相关性,三个研究区作物富集系数与根系土Na2O、SiO2、pH呈正相关性,而与根系土S、P、有机碳呈负相关性。说明偏碱性、砂质含量高的土壤有利于水稻对硒的吸收累积。
[Abstract]:Selenium is a necessary trace element in human body and animal. When the intake of selenium is insufficient or too low in human and animal, It can lead to selenium deficiency and reduce immunity. China is a selenium poor country. In 72% of China, the selenium deficiency or the deficiency of selenium intake in 2 / 3 of the population is insufficient. In recent years, the geochemical characteristics of selenium in soil have been observed. The study of ecological effects has become a hot spot in the applied geochemistry field in China and the whole world. Multi-objective regional geochemical surveys have delineated a number of soil selenium rich areas, although the total amount of soil selenium in some areas is relatively high. However, the amount of selenium that can be absorbed and utilized by plants is generally less than 5% of the total selenium in soil. A large number of studies show that selenium in plants mainly comes from the soil, and the selenium element affects human health through the migration of soil, crops and farm and livestock products. Therefore, the study of soil selenium sources, Activation migration and its absorption and enrichment in soil-crop system are of great significance. In this paper, the geochemical characteristics of selenium were analyzed and studied based on the geochemical survey data of 1: 50 000 land quality in typical selenium-rich landscape area. The results show that CaOG MgO in the soil of Boai County, Jiaozuo County is mainly affected by rock weathering in the north, and SiO2 is mainly controlled by the alluvial sediment in the south of the Yellow River. Mainly weathered by bedrock in the north, Effect of secondary enrichment of soil and pollution of human activities in Xiantao Zhanggou Town) soil elements are mainly controlled by Dongjing River and the content of SiO2Na2O is high in the area near the river. Al2O3, TFe2O3 and so on are located in the area far away from the river, where the content of se is high. Central and southeast corner of the study area, The element distribution in Qitian Town, Mianzhu, is mainly influenced by the high background in the northwest and the influence of alluvium in Xiushui River, Mianyuan River, Shiting River and its tributaries. In the study area, the content of se in wheat and rice was higher than 0.04 mg / kg, the soil physical and chemical conditions had a significant effect on the enrichment coefficient of se in crops, and there was no significant correlation between se content in wheat and rice and se content in root soil. There was a positive correlation between the crop enrichment coefficient and the pH of Na _ 2O _ 2O _ 2 Sio _ 2, but a negative correlation with the root soil, which indicated that the soil with relatively alkaline and high sandy content was beneficial to the absorption and accumulation of selenium in rice.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S153
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本文编号：1510747