本文選題：高砷地下水 + 有機(jī)質(zhì)��； 參考：《中國地質(zhì)大學(xué)(北京)》2015年碩士論文

【摘要】：本文以內(nèi)蒙古河套平原高砷地下水地區(qū)為研究區(qū),鉆取兩個鉆孔,并采集沉積物樣品。通過資料整理、實(shí)地考察、野外取樣及室內(nèi)分析測試等過程,對研究區(qū)沉積物有機(jī)質(zhì)類型、起源及生物地球化學(xué)意義進(jìn)行研究。得到以下認(rèn)識:1、通過對樣品的無機(jī)組分測試分析,揭示了沉積物砷含量及影響因素。沉積物中砷的含量為4.44-28.89μg/g,均值為12.07μg/g;Fe2O3的含量在1.43-6.86%之間,均值為3.56%;Mn O的含量在0.03-0.135%之間,均值為0.06%。沉積物中砷的含量與鐵和錳的關(guān)系密切,存在明顯的正相關(guān)關(guān)系,相關(guān)系數(shù)分別為0.88、0.83。推測鐵和錳的氧化物吸附砷是沉積物富砷的主要原因。2、通過對樣品的總有機(jī)碳及有機(jī)碳同位素的測試分析,初步了解沉積物有機(jī)質(zhì)總體特征。研究區(qū)沉積物總有機(jī)碳含量較低,TOC含量在0.03-1.65%之間。砷與TOC含量也呈正相關(guān)關(guān)系,相關(guān)系數(shù)為0.56。樣品的δ13C取值在-24.24‰到-32.3‰之間,更接近于陸地植物的δ13C值,說明研究區(qū)沉積物中的有機(jī)質(zhì)主要來源于陸源植物。TOC與δ13C的分布與巖性關(guān)系密切,粘性樣品有機(jī)質(zhì)含量比砂質(zhì)樣品豐富。3、通過對沉積物標(biāo)志性有機(jī)質(zhì)的測試分析,揭示了有機(jī)質(zhì)起源特征及生物地球化學(xué)意義。沉積物有機(jī)質(zhì)中長鏈正構(gòu)烷烴含量豐富,且奇偶優(yōu)勢明顯。有機(jī)物主要來源于草本高等植物,少量來源于木本植物。部分樣品奇偶優(yōu)勢不明顯,且存在UCM,說明有成熟石油有機(jī)質(zhì)的侵入。藿烷類化合物和甾烷類化合物的構(gòu)型特征也說明有些樣品已達(dá)到成熟。研究表明,微生物首先利用石油起源的正構(gòu)烷烴,促進(jìn)吸附砷的鐵錳氧化物還原,從而導(dǎo)致砷的釋放。砂質(zhì)沉積物的有機(jī)質(zhì)含量較低,但含有石油起源的有機(jī)質(zhì),便于微生物的選擇性利用,使砷發(fā)生活化。
[Abstract]:In this paper, two boreholes were drilled from the high arsenic groundwater area of Hetao Plain, Inner Mongolia, and sediment samples were collected. The types, origins and biogeochemical significance of sediment organic matter in the study area were studied by means of data collation, field investigation, field sampling and laboratory analysis. The content of arsenic in sediment and its influencing factors were revealed by analyzing the inorganic components of the samples. The content of arsenic in sediment is 4.44-28.89 渭 g / g, the mean value is 12.07 渭 g / g, the content of Fe _ 2O _ 3 is between 1.43-6.86%, the mean value is between 0.03-0.135% and the average is 0.06%. The content of arsenic in sediment is closely related to iron and manganese, and there is a significant positive correlation between arsenic and manganese. The correlation coefficient is 0.888 ~ 0.83, respectively. It is inferred that the adsorption of arsenic by oxides of iron and manganese is the main cause of arsenic enrichment in sediments. The total organic carbon and organic carbon isotopes of the samples are measured and analyzed to preliminarily understand the overall characteristics of organic matter in sediments. The total organic carbon content of sediments in the study area is lower than that of TOC in the range of 0.03-1.65%. There was also a positive correlation between arsenic and TOC content, the correlation coefficient was 0.56. The 未 ~ (13) C values of the samples range from -24.24 鈥，

本文編號：2111371