贵州万山汞矿区石生苔藓植物总汞和甲基汞分布特征及生物指示意义

发布时间：2018-06-25 23:11

本文选题：汞矿区 + 苔藓　；参考：《贵州师范大学》2017年硕士论文

【摘要】：汞是全球性的重金属污染物,在大气中大部分以稳定态Hg0长期存在。苔藓由于其特殊的生理结构和代谢特征被公认为指示大气污染物的优良物种。本实验选择贵州省万山区我国西南地区一废弃汞矿区为研究区域,采集样品281份苔藓样品,分属5科7种,进行总汞和甲基汞含量的分析,结果显示,总汞含量范围0.21-126μg g-1,平均值4.9±11μg g-1,甲基汞含量范围0.64-262 ng g-1,平均值33±36 ng g-1。总汞和甲基汞含量最高的苔藓均采自于涉汞化工厂附近,暗示了在汞矿冶炼活动停止后,化工厂的生产活动是该区域最重要的污染源。不同苔藓种类之间对总汞的吸附能力没有明显的差异,证实综合使用多种苔藓作为大气汞的指示植物是可行的。在工业园及万山镇等地,选择7种优势种类苔藓84个样品,同时现场监测部分苔藓采样点近地表大气汞,定量分析苔藓汞和大气汞浓度之间的关系,结果显示,研究区苔藓汞浓度范围为0.96—126μgg-1,平均值80±46μgg-1,受触媒生产、废触媒回收等涉汞化工厂生产活动影响显著;苔藓汞与大气汞呈正相关关系,表现为线性拟合相关性系数r=0.93(n=12,P=0.01030),多项式拟合相关性系数r=0.96(n=12,P=0.01169),对数拟合相关性系数r=0.96(n=12,P=0.00469);选择对数拟合方程估算苔藓采样点大气汞浓度,发现拟合得到的大气汞空间分布特征和实测苔藓汞空间分布特征基本一致,从而通过定量/半定量方法证明了可以利用苔藓汞指示大气汞污染,研究成果为汞污染场地修复过程中的大气汞污染评价提供了新思路。采用主动监测的方法,以大灰藓为监测材料,在张妹家、工业园、四坑、五坑、梅子溪、敖寨乡、深冲口村7个监测点放置苔藓,于2016年5月至11月期间,回收样品6次,并进行总汞和甲基汞的测定。结果发现,监测点的苔藓中总汞和甲基汞含量基本呈现逐月升高的趋势,都不同程度的受到汞的污染,苔藓总汞主要来自大气,说明除了工业园是最主要的汞污染源以外,汞矿渣堆、交通和居民人为活动以及大气汞的迁移都有可能对局部大气造成汞污染。苔藓对大气中总汞的吸附未达到吸附饱和之前,含量随着曝露时间的增加而增加,大气中汞含量越高,苔藓的吸附速率越快,环境介质不同,吸附速率也不同,苔藓甲基汞的来源与大气有关。通过XNAES对苔藓样品分析发现,苔藓中汞的形态主要以辰砂(α-HgS)、黑辰砂(β-HgS)、半胱氨酸汞(Hg-Cys)形态存在。
[Abstract]:Mercury is a global heavy metal pollutant, most of which exist in the atmosphere as stable Hg _ 0 for a long time. Moss is recognized as an excellent species indicating atmospheric pollutants due to its special physiological structure and metabolic characteristics. In this study, 281 samples of lichen, belonging to 7 species belonging to 5 families, were collected from an abandoned mercury mine in southwest China in Wanshan District, Guizhou Province. The contents of total mercury and methylmercury were analyzed. The total mercury content ranged from 0.21-126 渭 g -1 with an average of 4.9 卤11 渭 g -1, and methylmercury from 0.64-262 ng g -1 with an average value of 33 卤36 ng g g -1. The moss with the highest content of total mercury and methylmercury is collected from the vicinity of the mercury-related chemical plant, implying that the production of the chemical plant is the most important source of pollution in the region after the mercury ore smelting activity is stopped. There is no significant difference in the adsorption capacity of total mercury among different species of moss, which proves that it is feasible to use multiple moss as indicator of atmospheric mercury. In the industrial park and Wanshan Town, 84 samples of lichen of 7 dominant species were selected. At the same time, the near surface atmospheric mercury of some moss sampling sites was monitored, and the relationship between moss mercury and atmospheric mercury concentration was quantitatively analyzed. The concentration of mercury in moss ranged from 0.96 to 126 渭 gg-1 with an average value of 80 卤46 渭 gg-1, which was significantly affected by the production activities of mercury-related chemical plants such as catalyst production and waste catalyst recovery, and there was a positive correlation between moss mercury and atmospheric mercury. The linear fitting correlation coefficient r = 0.93 (n = 12), polynomial fitting correlation coefficient r ~ (0.96), logarithmic fitting correlation coefficient r = 0.96 (n ~ (12) P ~ (1) = 0.00469), the logarithmic fitting equation was used to estimate the atmospheric mercury concentration in moss sampling sites, and a logarithmic fitting equation was used to estimate the atmospheric mercury concentration in moss sampling sites. It was found that the fitted spatial distribution of mercury in the atmosphere was basically consistent with the measured spatial distribution of mercury in moss, and it was proved by quantitative / semi-quantitative methods that mercury in the atmosphere could be used to indicate mercury pollution in the atmosphere. The results provide a new idea for the assessment of atmospheric mercury pollution during the remediation of mercury contaminated sites. Using the active monitoring method, the moss was placed in 7 monitoring sites in Zhangmei's house, industrial park, Sikeng, Wukeng, plum stream, Aozhai village and Shenchongkou village. Samples were recovered 6 times between May and November 2016. The total mercury and methylmercury were determined. The results showed that the content of total mercury and methylmercury in moss at the monitoring sites showed a trend of increasing month by month, and they were polluted by mercury to varying degrees, and the total mercury of moss mainly came from the atmosphere, indicating that, in addition to industrial parks, it was the most important source of mercury pollution. Mercury slag stacks, traffic, human activities and atmospheric mercury transport are likely to cause mercury pollution in the local atmosphere. Before the adsorption of total mercury in the atmosphere reached saturation, the content of total mercury increased with the increase of exposure time. The higher the mercury content in the atmosphere, the faster the adsorption rate of moss, the different environmental media, and the different adsorption rate. The origin of methylmercury in moss is related to the atmosphere. By XNAES analysis of moss samples, it was found that the main forms of mercury in bryophytes were 伪 -HgS, 尾 -HgS and Hg-Cys.
【学位授予单位】：贵州师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X173

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