| 不同年限露天煤矿排土场土壤剖面溶解性有机质荧光和吸光特征 |
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| 引用本文： | 张莉,刘涵,赵海超,孙清轩,曹志国.不同年限露天煤矿排土场土壤剖面溶解性有机质荧光和吸光特征[J].环境科学研究,2021,34(8):1941-1951. |
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| 作者姓名： | 张莉 刘涵 赵海超 孙清轩 曹志国 |
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| 作者单位： | 1.北京工业大学, 城镇污水深度处理与资源化利用技术国家工程实验室, 北京 100124 |
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| 基金项目： | 煤炭开采水资源保护与利用国家重点实验室开放基金项目GJNY-18-73.18北京市科技重大专项Z181100005318001 |
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| 摘 要： | 露天煤矿开采对土壤剖面各土层溶解性有机质（DOM）组分含量影响巨大.该研究采用三维荧光光谱（3D-EEM）和紫外-可见光谱（UV-vis）对锡林浩特露天煤矿1~7年排土场土壤剖面（0~100 cm）DOM荧光和吸光特征深入分析，解析排土场生态演替过程中土壤剖面DOM组分及来源时空变化.结果表明:①露天煤矿排土场土壤剖面各土层w（DOC）在102.70~475.80 mg/kg之间，荧光组分中蛋白质类组分占比（29.97%~60.39%）最高，类腐殖酸组分占比（16.09%~44.27%）次之.土壤剖面DOM主要来源于微生物代谢产物，芳香性、腐殖化程度较低，且随排土场年限增加，各土层DOM紫外吸光组分芳香环中羰基、羧基、羟基、酯类含量增加，类腐殖酸组分占比先降后增，蛋白质类组分占比先增后降，类富里酸组分占比呈下降趋势.②随土壤深度增加，DOM含量呈上升趋势，DOM自生源特征及土壤微生物活性减弱，次表层（20~40 cm）出现明显波峰.随排土场年限增加，深层土壤DOM荧光组分中蛋白质类组分占比呈下降趋势，类富里酸组合占比垂向变化较小，类腐殖酸组分占比呈增加趋势.随着地表植被由无到有，DOM自生源特征降低，腐殖化程度增强.③排土场土壤剖面pH可作为评估DOM腐殖化程度的良好指标，总氮（TN）含量可作为指示DOM分子量重要指标.研究显示，不同年限露天煤矿排土场土壤剖面DOM荧光和吸光特征能够作为露天煤矿环境治理与生态恢复的评价指标.
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| 关 键 词： | 溶解性有机质(DOM) 土壤 露天煤矿排土场 三维荧光光谱(3D-EEM) 紫外-可见光谱(UV-vis) |
| 收稿时间： | 2020-12-22 |
Fluorescence and Absorption Characteristics of Dissolved Organic Matter in Soil Profile of Open-Pit Coal Mine Dump in Different Years |
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| Affiliation: | 1.National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Beijing University of Technology, Beijing 100124, China2.Key Laboratory of Water Resource Protection and Utilization in Coal Mining, China Energy Investment Corporation State, Beijing 102211, China3.Hebei Key Laboratory of Quality & Safety Analysis-Testing for Agro-Products and Food, Hebei North University, Zhangjiakou 075000, China |
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| Abstract: | Open-pit coal mining has a significant impact on the content and composition of dissolved organic matter (DOM) in each layer of soil profile. In this study, three-dimensional excitation-emission matrix fluorescence spectroscopy (3D-EEM) and ultraviolet-visible spectroscopy (UV-vis) were used to analyze the DOM in the soil profile (0-100 cm) of Xilinhot open-pit coal mine dump from 1-7 years, and to determine the spatiotemporal variation of DOM composition and source in the soil profile during the ecological succession of the open-pit coal mine dump. The results showed that: (1) The DOC content in the soil profile of the open-pit coal mine dump ranged from 102.70 mg/kg to 475.80 mg/kg. The proportion of protein-like compounds (29.97%-60.39%) was the highest, followed by the humic content (16.09%-44.27%). The DOM in the open-pit coal mine dump was mainly derived from microbial metabolites and had low aromaticity and humification characteristics. UV-vis analysis showed that with the increase of the number of years, the content of carbonyl, carboxyl, hydroxyl and ester in the aromatic ring of DOM increased. The proportion of humic substances first decreased and then increased, and the proportion of protein-like compounds first increased and then decreased. The proportion of fulvic acids showed a downward trend. (2) With the increase of soil depth, DOM content showed an upward trend, with its lower autogenous characteristics and lower microbial activity in soil, and obvious peaks appeared in the subsurface layer (20-40 cm). The proportion of protein-like materials in DOM fluorescence components of deep soils decreased with the increase of years. The vertical change of fulvic acids was less in open-pit coal mine dump of different years, and the proportion of humic acids increased in open-pit coal mine dump with the increase of years. As the surface vegetation grew out of nothing, the autogenous characteristics of DOM decreased and its degree of humification increased. (3) The results showed that the pH of soil profile could be used as a good indicator to evaluate the humification degree of DOM, and the total nitrogen (TN) could indicate the molecular weight of DOM. The research shows that DOM fluorescence and absorption characteristics in soil profile of open-pit coal mine dump in different years can be used to evaluate the environmental management and ecological restoration of open-pit coal mine dump. |
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