| 微生物对汞矿区农田土壤汞甲基化的影响 |
| 摘要点击 1884 全文点击 689 投稿时间：2016-11-24 修订日期：2017-02-10 |
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| 中文关键词 土壤 甲基汞 汞矿区 硫酸盐还原菌 稻田土壤 |
| 英文关键词 soil methylmercury mercury mining area sulfate reducing bacteria paddy soils |
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| 中文摘要 |
| 为研究典型汞矿区农田土壤中汞的甲基化作用，实验以受汞污染的旱田土壤和稻田土壤为对象，分别进行灭菌，促进硫酸盐还原菌（SRB）活性处理，抑制SRB活性处理以及促进铁还原菌（FeRB）活性处理，分析非微生物作用和微生物作用对土壤甲基汞（MeHg）生成的影响.结果表明，促进SRB活性处理的土壤MeHg生成量最高，其中旱田土MeHg增量为0.15~0.38 μg·kg-1，稻田土壤MeHg增量为1~2 μg·kg-1；抑制SRB活性处理和促进FeRB活性处理的MeHg增量较小，最高值仅为0.025 μg·kg-1.相比于旱田土壤，稻田土壤具有更高的汞甲基化能力，其MeHg生成量是旱田土壤的4~9倍.土壤SRB数量与MeHg生成量具有相同的变化趋势，二者具有显著的正相关性（R2=0.57，P<0.01）.因此，该研究区土壤汞甲基化作用主要是微生物汞甲基化作用，且主要的汞甲基化细菌是SRB.此外，稻田是农田中MeHg生成的活跃地区，在评估和控制MeHg对人体健康危害时需要重点关注. |
| 英文摘要 |
| In order to study the main effect of microbial activities on mercury(Hg) methylation in farmland, mercury contaminated upland soils and paddy soils near Hg mining area were sampled as experimental soils. Four treatments were designed including only sterilization as the control, accelerating the activities of sulfate reducing bacteria(SRB), inhibiting the SRB's activities, and accelerating the activities of iron-reducing bacteria(FeRB), to know the effects of microbial and non-microbial factors on mercury methylation in soils. The results were as follows:the highest concentration of methylmercury(MeHg) was observed in soils with SRB accelerated treatment, and the increments of MeHg concentrations in upland soils and paddy soils ranged from 0.15 μg·kg-1 to 0.38 μg·kg-1 and 1 μg·kg-1 to 2 μg·kg-1, respectively. Comparatively, little increments of MeHg concentration were seen in soils with SRB inhibited treatment and FeRB accelerated treatment, which were lower than 0.025 μg·kg-1. Compared with upland soils, more MeHg was formed in Paddy soils and the concentrations of MeHg in paddy soils were 4-9 times of that in upland soils. Variation in the number of SRB in soils was similar to that in the concentration of MeHg in soils, and the number of SRB was positively correlated with the concentration of MeHg concentrations in soils(R2=0.57,P<0.01). The above results indicated that activities of reducing bacteria, especially SRB, played key role in the methylation in soils. In addition, more attention should be paid to paddy soils due to the high potential of methylation when conducting any assessment and taking any measure to manage the health risk caused by the exposure to mercury. |
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