摘要
为探究堆积煤矸石所产生的重金属的污染问题,本文以北京市门头沟5个典型矿区为研究对象,采集矸石山堆积表面风化煤矸石共45个样品,分析测试矸石样品中汞(Hg)的含量,对不同理化性质下各重金属的变化规律进行了初步探讨;利用改进BCR连续提取法,研究样品中Hg的赋存形态,分析其生物可利用性;采用富集因子法、地累积指数法、风险编码法和个体污染因子法对Hg进行有效性评价;再模拟酸雨条件下Hg的溶出特征及影响因素。结果表明,该研究区Hg的含量为0.085—0.519 mg·kg^(−1),均值为0.169 mg·kg^(−1),超过了北京市土壤背景值,超标倍数为4.225;Hg的平均富集系数与地累积指数分别为4.53和1.35,均表现为中度污染;风险编码法和次生相与原生相比值法结果显示为低风险和轻度污染,占比分别为86.67%和31.11%;Hg与Eh呈显著负相关,与含水率呈显著正相关;煤矸石中Hg的主要赋存形态为可氧化态Hg和残渣态Hg,其中可还原态Hg与可氧化态Hg存在显著负相关,TOC、pH与可还原态Hg呈显著正相关;静态淋溶试验表明,雨水酸度、粒径、固液比均会影响Hg的溶出量,在一定条件范围内,煤矸石浸泡液中Hg的溶出量随pH的增大而减小,随粒径的增大而增大,随固液比的增大而增大;在静态淋溶模拟试验中,Hg的最大溶出量严重超出国家标准,为Ⅳ类水质的6.4倍。该研究结果可为进一步了解Hg在煤矸石中的活性、迁移规律、赋存形态及永定河Hg的污染治理提供科学依据。
In order to explore the pollution of heavy metals caused by the accumulation of coal gangue,this paper takes 5 typical mining areas in Mentougou,Beijing as the research object.A total of 45 samples of weathered coal gangue on the surface of the gangue hill were collected to analyze and test the content of mercury(Hg)in the gangue samples,and a preliminary discussion on the changing laws of various heavy metals under different physical and chemical properties were investigated;using the improved BCR continuous extraction method to study the occurrence of Hg in the sample and analyze its bioavailability;and the enrichment factor method,the geoaccumulation index method,risk coding method and individual pollution factor method were used to evaluate the effectiveness of Hg;the dissolution characteristics and factors affecting Hg under acid rain conditions were then simulated.The results showed that the content of Hg in the study area was 0.085—0.519 mg·kg^(−1),with an average value of 0.169 mg·kg^(−1),which exceeded the Beijing soil background value with a multiple of 4.225;the average enrichment coefficient of Hg and land accumulation index are 4.53 and 1.35 respectively,both of which are moderate pollution;the results of risk coding method and secondary phase to primary phase ratio method show low risk and light pollution,accounting for 86.67%and 31.11%respectively;Hg are significantly negatively correlated with Eh,and positively correlated with moisture content;the main occurrence forms of Hg in coal gangue are oxidizable Hg and residual Hg,among which there is a significant negative correlation between reducible Hg and oxidizable Hg,there is a significant positive correlation between TOC,pH and the reducible Hg;the static leaching test shows that the acidity of rainwater,particle size,and solid-liquid ratio will all affect the dissolution of Hg.Within a certain range of conditions,the dissolution of Hg in the coal gangue soaking solution decreases with pH increases,and it increases with the increase of particle size and solid-liquid ratio;In the static leaching simulation test,the maximum dissolution of Hg seriously exceeded the national standard,and it was 6.4 times as much as the value of ClassⅣwater quality.The research results can provide a scientific basis for further understanding of the activity,migration law,occurrence form of Hg in coal gangue and the Hg pollution control of Yongding River.
作者
唐莹
武相林
孙敏
郝亚婷
晏晓筱
王敏
季宏兵
TANG Ying;WU Xianglin;SUN Min;HAO Yating;YAN Xiaoxiao;WANG Min;JI Hongbing(School of Resources,Environment and Tourism,Capital Normal University,Beijing,100048,China;Beijing North Energy Saving and Environmental Protection Co.,Ltd.,Beijing,100070,China;School of Civil and Environmental Engineering,University of Science and Technology Beijing,Beijing,100083,China)
出处
《环境化学》
CAS
CSCD
北大核心
2022年第3期962-976,共15页
Environmental Chemistry
基金
国家自然科学基金(41473122,41173113)资助.
关键词
汞
煤矸石
赋存形态
静态淋溶
mercury
coal gangue
occurrence states
static leaching.
