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首页> 外文期刊>Environmental Science & Technology >Forest Fire Effects On Mercury Deposition In The Boreal Forest
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Forest Fire Effects On Mercury Deposition In The Boreal Forest

机译：森林火灾对北方森林汞沉积的影响

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Paniculate Hg (pHg) is a component of smoke from biomass burning and has the potential for local redeposition. Throughfall (precipitation collected beneath a conifer or deciduous canopy) and open precipitation samples were collected pre-and postfire in 2005 and 2006 using passive precipitation collectors across the Superior National Forest, located in northern Minnesota, USA. Samples were collected approximately every two weeks and analyzed for total Hg (THg) and methyl Hg (MeHg). THg concentrations increased significantly postfire in conifer throughfall (>4× increase), open precipitation (2.5×), and when all canopy types were considered (2.9×). MeHg concentrations also increased after fire regardless of the covertype(coniferthroughfall:10x increase; open precipitation: 3.5× increase; deciduous throughfall: 1.7× increase; all canopy types analyzed together: 8× increase). Total Hg deposition increased significantly under conifer cover (3.8×). Methyl Hg deposition increased significantly after fire when all canopy types were analyzed together (4.6×) and in conifer throughfall (5.9×). Canopy type influenced the magnitude of postfire THg and MeHg increase and the duration of elevated MeHg levels. Particulate Hg present in forest fire smoke represents a short-term source of increased Hg in the atmosphere that is available for local redeposition during and following fire.
机译：颗粒状汞（pHg）是生物质燃烧产生的烟雾的一部分，具有潜在的再沉积潜力。在美国明尼苏达州北部的上等国家森林中，使用被动降水收集器在2005年和2006年大火前后收集了贯穿全天（针叶树或落叶树冠下的降水）和露天降水样本。大约每两周收集一次样品，并分析总Hg（THg）和甲基Hg（MeHg）。针叶林穿透后（> 4倍增加），开放降水（2.5倍）以及考虑所有树冠类型（2.9倍）后，THg浓度显着增加。不论覆盖类型如何，火灾后MeHg浓度也都会增加（针叶树穿透力：增加10倍；开放降水：增加3.5倍；落叶穿透力：增加1.7倍；一起分析的所有冠层类型：增加8倍）。在针叶覆盖下，总汞沉积显着增加（3.8倍）。一起分析所有树冠类型（4.6倍）和针叶树穿透（5.9倍）时，火灾后甲基汞的沉积显着增加。冠层类型影响着火后THg和MeHg增加的幅度以及MeHg水平升高的持续时间。森林火灾烟雾中存在的微粒汞是大气中汞增加的短期来源，可在火灾期间和之后进行局部再沉积。

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