本文關(guān)鍵詞： 典型景觀區(qū) Se 地球化學(xué)特征 富集系數(shù) 生態(tài)效應(yīng)　出處：《中國(guó)地質(zhì)大學(xué)(北京)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：硒是人體和動(dòng)物必需的微量元素,當(dāng)人和動(dòng)物硒攝入量不足或過(guò)低時(shí),會(huì)引發(fā)缺硒病癥并降低免疫力。我國(guó)是一個(gè)貧硒國(guó)家,72%地區(qū)缺硒或低硒,2/3的人口硒攝入不足。近十幾年來(lái)土壤硒地球化學(xué)特征、及生態(tài)效應(yīng)研究已經(jīng)成為我國(guó)乃至全世界應(yīng)用地球化學(xué)領(lǐng)域的研究熱點(diǎn)。多目標(biāo)區(qū)域地球化學(xué)調(diào)查已經(jīng)圈出不少土壤硒富集區(qū),雖然一些地區(qū)的土壤硒總量雖然較高,但真正能被植物吸收利用的硒卻占土壤總硒比例一般不到5%。大量研究表明,植物中硒主要來(lái)源于土壤,硒元素以土壤-農(nóng)作物-農(nóng)畜產(chǎn)品的遷移途徑影響到人體健康,因此研究土壤硒來(lái)源、活化遷移及其在土壤—作物系統(tǒng)中的吸收富集規(guī)律具有重要意義。本文以典型富硒景觀區(qū)1:5萬(wàn)土地質(zhì)量地球化學(xué)調(diào)查資料開(kāi)展硒地球化學(xué)特征分析和研究。結(jié)果表明:(1)焦作博愛(ài)縣研究區(qū)土壤中CaO、MgO等主要受北部巖石風(fēng)化影響,SiO2等主要受南部黃河沖洪積物控制,Se元素呈現(xiàn)北高南低的特征,主要受到北部基巖風(fēng)化、成土次生富集和人類活動(dòng)污染影響;(2)仙桃張溝鎮(zhèn)研究區(qū)土壤元素主要受東荊河控制,SiO2、Na2O在離河近的區(qū)域含量高,Al2O3、TFe2O3等在遠(yuǎn)離河道的區(qū)域含量較高,Se元素高背景區(qū)位于研究區(qū)中部及東南角,源自于上游恩施紫陽(yáng)等地經(jīng)由長(zhǎng)江、漢水搬運(yùn)沉積;(3)綿竹齊天鎮(zhèn)研究區(qū)元素分布主要受西北部高背景以及秀水河、綿遠(yuǎn)河、石亭江及其支流沖洪積物的影響,Se元素呈西北高、東南低的分布態(tài)勢(shì)。研究區(qū)小麥及水稻富硒率高,Se含量高于0.04mg/kg的樣品占99.4%;土壤理化條件對(duì)作物Se的富集系數(shù)有顯著影響,小麥和水稻中Se含量與根系土Se含量無(wú)顯著相關(guān)性,三個(gè)研究區(qū)作物富集系數(shù)與根系土Na2O、SiO2、pH呈正相關(guān)性,而與根系土S、P、有機(jī)碳呈負(fù)相關(guān)性。說(shuō)明偏堿性、砂質(zhì)含量高的土壤有利于水稻對(duì)硒的吸收累積。
[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.
【學(xué)位授予單位】：中國(guó)地質(zhì)大學(xué)(北京)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：S153
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本文編號(hào)：1510747