硒对水稻甲基汞吸收和迁移转化的影响
发布时间：2018-07-13 21:38
【摘要】：汞是一种全球关注的高毒性金属元素,汞矿区一直是汞污染研究的热点区域之一。研究表明,位于贵州省东部的万山汞矿区的水稻可以富集甲基汞,食用大米是当地居民甲基汞暴露的主要途径。同时,硒作为万山汞矿的伴生元素可能会影响汞的生物地球化学循环。因此,非常有必要对稻田生态系统硒对甲基汞迁移转化的影响进行研究。本研究通过野外调查实验和室内模拟实验两方面开展。系统采集万山汞矿区的稻米样品,测定其总汞、甲基汞以及总硒含量,分析稻米汞、硒之间的相互关系,探讨硒对稻米中总汞和甲基汞生物富集的影响。此外,通过室内模拟实验,水培种植水稻幼苗,进行硒添加背景下的水稻幼苗对甲基汞的吸收动力学实验,以探究硒对水稻甲基汞吸收和迁移转化的影响,为汞污染地区的生物修复提供新的途径和启示。1)贵州万山汞矿区稻米总汞含量几何平均值为24.0 ng·g-1(2.40~401 ng·g-1),51%的样品超过我国食品汞限量标准(20 ng·g-1);甲基汞含量几何平均值为8.97ng·g-1(1.10~45.1 ng·g-1),占总汞平均比例的44.8±23.9%。稻米总汞含量分布表现为上游尾矿堆附近区域汞污染严重,随流域往下汞含量显著降低,这表明汞矿活动是当地稻米严重汞污染的原因。万山汞矿区稻米硒含量几何平均值为124.3 ng·g-1(21.45~1991 ng·g-1),显著高于我国粮食硒的平均含量(40~70ng·g-1),这与当地土壤高硒含量有关。2)万山汞矿区稻米硒含量与总汞含量无显著相关性。当稻米硒及甲基汞含量均较低时,硒与甲基汞之间无明显相关性;当硒或甲基汞含量较高时,两者呈现出明显的反相关关系,这表明硒可以显著抑制水稻对甲基汞的吸收和富集。3)室内模拟实验表明,水稻生长期间,硒对水稻幼苗甲基汞的含量有显著影响。一定浓度范围内Se(VI)能有效抑制水稻甲基汞的吸收,且不同浓度Se(VI)其抑制作用存在差异。而同一浓度的Se(IV)则能促进水稻对甲基汞的吸收。4)水稻根系对甲基汞富集能力较强,但向地上部分运转则相对困难。硒的添加对甲基汞在水稻根部和茎叶的分配具有显著影响(P0.05)。水稻根系对甲基汞的吸收系数随水稻生长而增大,变化范围为2.54~122;而水稻转运系数则随水稻生长呈下降趋势,变化范围为0.22~0.74。Se(VI)处理在某一阈值内能降低水稻根系对甲基汞的富集以及根部向茎叶转运甲基汞的能力,而Se(IV)处理则会促进水稻根部对MeHg的吸收。5)水稻至成熟时稻米甲基汞含量的估算表明,Se(VI)对稻米甲基汞的富集表现为抑制作用,而Se(IV)则可能会促进稻米中甲基汞的富集。
[Abstract]:Mercury is a highly toxic metal element of global concern. Mercury mining area has always been one of the hot areas of mercury pollution research. The study shows that rice can enrich methyl mercury in the Wanshan mercury mine area in the eastern part of Guizhou province. Therefore, it is very necessary to study the effect of selenium on the migration and transformation of methyl mercury in rice field ecosystem. This study is carried out through two aspects of field investigation and indoor simulation experiments. The rice samples of the Wanshan mercury mining area are collected systematically to determine the total mercury, methyl mercury and total selenium content, and the analysis of rice rice The relationship between mercury and selenium, and the effects of selenium on the bioaccumulation of total and methyl mercury in rice. In addition, the experiment on the absorption and transformation of methyl mercury from rice seedlings in Rice Seedlings under the background of selenium supplementation was carried out to explore the effects of selenium on the absorption and transfer of methyl mercury in rice. The bioremediation of the area provides a new way and inspiration.1) the geometric mean value of the total mercury content in the Guizhou Wanshan mercury mining area is 24 ng. G-1 (2.40~401 ng. G-1), and 51% of the samples exceed our national food mercury limit standard (20 ng. G-1); the geometric mean of the methyl mercury content is 8.97ng g-1 (1.10~45.1 ng.), accounting for the average percentage of total mercury 44.8 +. The distribution of the total mercury content of the rice was serious in the vicinity of the upstream tailings heap, and the mercury content decreased significantly with the lower mercury content in the basin. This indicates that the mercury mine activity is the cause of serious mercury pollution in the local rice. The geometric mean value of the rice selenium content in the Wanshan mercury mine is 124.3 ng. G-1 (21.45~1991 ng. G-1), which is significantly higher than the average content of the grain selenium in China (40~ 70ng. G-1) there was no significant correlation between the content of rice selenium and total mercury content in the Wanshan mercury mining area. There was no significant correlation between the content of selenium and the total mercury content in the Wanshan mercury mining area. There was no significant correlation between selenium and methyl mercury when the content of rice selenium and methyl mercury was low. When the content of selenium or methyl mercury was high, the two showed a clear anti correlation relationship, which indicated that selenium could be significantly inhibited. Indoor simulation experiments on the absorption and enrichment of methyl mercury in rice showed that the content of methyl mercury in rice seedlings was significantly affected by selenium during the growth period of rice. Se (VI) could effectively inhibit the absorption of methyl mercury in rice, and the different concentrations of Se (VI) were different in a certain concentration range, while the same concentration of Se (IV) could promote rice treatment. The absorption of methyl mercury by.4) the ability of rice roots to enrich methyl mercury is stronger, but it is relatively difficult to run to the upper part of the earth. The addition of selenium to the distribution of methyl mercury in the roots and stems of rice has significant influence (P0.05). The absorption coefficient of methyl mercury in rice root increases with the growth of rice, and the range of variation is 2.54~122. As the growth of rice decreased, the range of variation was 0.22~0.74.Se (VI) treatment in a certain threshold to reduce the enrichment of rice roots to methyl mercury and the ability to transport methyl mercury to the stems and leaves, while Se (IV) treatment would promote the absorption of MeHg by the rice root to MeHg. The estimation of the content of methyl mercury in rice from rice to maturity showed that Se (VI) was to rice. The enrichment of M methyl mercury is inhibited, while Se (IV) may promote the enrichment of methylmercury in rice.
【学位授予单位】：贵州大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S511;X56
本文编号：2120815
[Abstract]:Mercury is a highly toxic metal element of global concern. Mercury mining area has always been one of the hot areas of mercury pollution research. The study shows that rice can enrich methyl mercury in the Wanshan mercury mine area in the eastern part of Guizhou province. Therefore, it is very necessary to study the effect of selenium on the migration and transformation of methyl mercury in rice field ecosystem. This study is carried out through two aspects of field investigation and indoor simulation experiments. The rice samples of the Wanshan mercury mining area are collected systematically to determine the total mercury, methyl mercury and total selenium content, and the analysis of rice rice The relationship between mercury and selenium, and the effects of selenium on the bioaccumulation of total and methyl mercury in rice. In addition, the experiment on the absorption and transformation of methyl mercury from rice seedlings in Rice Seedlings under the background of selenium supplementation was carried out to explore the effects of selenium on the absorption and transfer of methyl mercury in rice. The bioremediation of the area provides a new way and inspiration.1) the geometric mean value of the total mercury content in the Guizhou Wanshan mercury mining area is 24 ng. G-1 (2.40~401 ng. G-1), and 51% of the samples exceed our national food mercury limit standard (20 ng. G-1); the geometric mean of the methyl mercury content is 8.97ng g-1 (1.10~45.1 ng.), accounting for the average percentage of total mercury 44.8 +. The distribution of the total mercury content of the rice was serious in the vicinity of the upstream tailings heap, and the mercury content decreased significantly with the lower mercury content in the basin. This indicates that the mercury mine activity is the cause of serious mercury pollution in the local rice. The geometric mean value of the rice selenium content in the Wanshan mercury mine is 124.3 ng. G-1 (21.45~1991 ng. G-1), which is significantly higher than the average content of the grain selenium in China (40~ 70ng. G-1) there was no significant correlation between the content of rice selenium and total mercury content in the Wanshan mercury mining area. There was no significant correlation between the content of selenium and the total mercury content in the Wanshan mercury mining area. There was no significant correlation between selenium and methyl mercury when the content of rice selenium and methyl mercury was low. When the content of selenium or methyl mercury was high, the two showed a clear anti correlation relationship, which indicated that selenium could be significantly inhibited. Indoor simulation experiments on the absorption and enrichment of methyl mercury in rice showed that the content of methyl mercury in rice seedlings was significantly affected by selenium during the growth period of rice. Se (VI) could effectively inhibit the absorption of methyl mercury in rice, and the different concentrations of Se (VI) were different in a certain concentration range, while the same concentration of Se (IV) could promote rice treatment. The absorption of methyl mercury by.4) the ability of rice roots to enrich methyl mercury is stronger, but it is relatively difficult to run to the upper part of the earth. The addition of selenium to the distribution of methyl mercury in the roots and stems of rice has significant influence (P0.05). The absorption coefficient of methyl mercury in rice root increases with the growth of rice, and the range of variation is 2.54~122. As the growth of rice decreased, the range of variation was 0.22~0.74.Se (VI) treatment in a certain threshold to reduce the enrichment of rice roots to methyl mercury and the ability to transport methyl mercury to the stems and leaves, while Se (IV) treatment would promote the absorption of MeHg by the rice root to MeHg. The estimation of the content of methyl mercury in rice from rice to maturity showed that Se (VI) was to rice. The enrichment of M methyl mercury is inhibited, while Se (IV) may promote the enrichment of methylmercury in rice.
【学位授予单位】：贵州大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S511;X56
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