| 大兴安岭南瓮河湿地类型对土壤中甲基汞分布的影响 |
| 摘要点击 1444 全文点击 657 投稿时间：2018-05-24 修订日期：2018-06-20 |
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| 中文关键词 南瓮河 湿地 甲基汞 总汞 土壤性质 |
| 英文关键词 Nanweng River wetland methylmercury total mercury soil properties |
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| 中文摘要 |
| 甲基汞（methylmercury，MeHg）是所有汞（Hg）的化合物中毒性最强的有机物，其毒性远远大于无机Hg.MeHg可能通过食物链的传递进入人体，威胁人类健康.本研究以大兴安岭南瓮河国家自然保护区为研究对象，分析了中位沼泽、低位沼泽、岛状林、森林土4种湿地类型土壤样品MeHg含量分布差异以及土壤性质对MeHg含量的影响.结果表明：①总汞（THg）与MeHg含量变化趋势不一致，THg含量的高低顺序为：岛状林[（138.76±101.97）mg·kg-1] > 森林土[（117.57±32.44）mg·kg-1] > 低位沼泽[（71.8±1.42）mg·kg-1] > 中位沼泽[（65.11±26.69）mg·kg-1]，而MeHg含量高低顺序为：岛状林[（1.14±1.15）μg·kg-1] > 中位沼泽[（0.87±1.06）μg·kg-1] > 低位沼泽[（0.28±0.06）μg·kg-1] > 森林土[（0.1±0.05）μg·kg-1]；②岛状林和中位沼泽中MeHg的含量较高且随采样位点波动较大，低位沼泽和森林土中MeHg的含量较低，每个取样点之间变化较小；③沼泽湿地形成的时间越长，MeHg的含量越多，即中位沼泽[（0.87±1.06）μg·kg-1] > 低位沼泽[（0.28±0.06）μg·kg-1]；土壤pH与MeHg的含量呈显著正相关（P<0.05）；含水率（WC）、有机质（OM%）、总碳（C%）、总汞（THg）含量在中位沼泽地区与MeHg含量呈显著的线性关系（P<0.05）；土壤pH、铵态氮（NH4+-N）含量在岛状林地区与MeHg含量呈显著的线性关系（P<0.05）.本研究阐明了不同湿地生态系统MeHg的分布特点及其影响因素，为全面评价湿地生态系统中MeHg积累及其环境风险提供了数据支撑. |
| 英文摘要 |
| Methylmercury (MeHg) is the most toxic organic matter of all mercury (Hg) compounds. Its toxicity is far higher than that of inorganic Hg. Methylmercury can enter the human body through food, threatening human health. Based on the Nanweng River National Nature Reserve in the Greater Xing'an Mountains, the differences in the distribution of MeHg in soil samples collected from four types of wetlands, including medium swamp, low swamp, island forest, and forest soil, and the effect of the soil properties on the MeHg content were investigated in this study. The results show that:① the trends of the total Hg and MeHg levels are inconsistent. The order of the mean total Hg content is island forest (138.76 mg·kg-1±101.97 mg·kg-1) > forest soil (117.57 mg·kg-1±32.44 mg·kg-1) > low swamp (71.8 mg·kg-1±1.42 mg·kg-1) > median swamp (65.11 mg·kg-1±26.69 mg·kg-1), while the mean MeHg content is in the order of island forest (1.14 μg·kg-1±1.15 μg·kg-1) > medium swamp (0.87 μg·kg-1±1.06 μg·kg-1) > low swamp (0.28 μg·kg-1±0.06 μg·kg-1) > forest soil (0.1 μg·kg-1±0.05 μg·kg-1); ② the contents of MeHg in the island forest and medium swamp were relatively high and fluctuated dramatically, whereas the contents of MeHg in the low swamp and forest soil were lower and showed little change between each sampling point; ③ the longer the marsh wetland formation was, the higher was the MeHg content, that is, median swamp (0.87 μg·kg-1±1.06 μg·kg-1) > low swamp (0.28 μg·kg-1±0.06 μg·kg-1); the soil pH was positively correlated with MeHg (P<0.05); in the medium swamp area, the content of MeHg was positively related to the water content (WC), organic matter (OM%), carbon (C%), and total mercury (THg; P<0.05); in the island forest areas, the MeHg content showed a linear relationship with the soil pH and NH4+-N (P<0.05). This study reveals the distribution characteristics of MeHg and its influencing factors for different wetland ecosystems, providing data supporting the comprehensive evaluation of MeHg accumulation in wetland ecosystems. |
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