Mercury and trace elements in cloud water and precipitation collected on Mt. Mansfield, Vermont.
Mercury and trace elements in cloud water and precipitation collected on Mt. Mansfield, Vermont.
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DOI：
10.1039/b210124f
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发表时间：
2003-07
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影响因子：
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通讯作者：
Elizabeth G. Malcolm;G. Keeler;S. Lawson;Timothy D Sherbatskoy
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文献类型：
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作者：
Elizabeth G. Malcolm;G. Keeler;S. Lawson;Timothy D Sherbatskoy
由于缺乏对云雾水中汞和微量元素的高质量测量，因此设计了一种新的收集器，用于对云雾水进行清洁连续采样。 1998年8月1日至10月31日期间，在美国东北部佛蒙特州曼斯菲尔德山发生的九次非降水云事件中收集了云水。在其中六次事件中收集了连续样本。汞云水浓度范围为7.5至71.8 ng l(-1)，平均值为24.8 ng l(-1)。液态水含量解释了大约 60% 的汞云浓度变化。研究发现汞云水浓度最高与来自大西洋中部和俄亥俄河谷的运输有关，最低浓度与来自加拿大曼斯菲尔德山北部的运输有关。作为长期沉积研究的一部分，在曼斯菲尔德山脚下为期十周的云采样期间收集了 29 个事件降水样本。云水中的汞浓度与降水汞浓度（中位数10.5 ng l(-1)）相似，但平均较高（中位数为12.5 ng l(-1)）。通过 ICP-MS 分析了云和降水样品中的 15 种微量元素，包括 Mg、Cu、Zn、As、Cd 和 Pb。对于来自同一来源区域的样品，主要来自人为而非地壳的元素在云水中的平均浓度高于降水。一种可能的解释是，降水云中地壳元素的云内清除量大于非降水云，而云下地壳元素的清除量大于人为气溶胶。
The lack of high quality measurements of Hg and trace elements in cloud and fog water led to the design of a new collector for clean sequential sampling of cloud and fog water. Cloud water was collected during nine non-precipitating cloud events on Mt. Mansfield, VT in the northeastern USA between August 1 and October 31, 1998. Sequential samples were collected during six of these events. Mercury cloud water concentrations ranged from 7.5 to 71.8 ng l(-1), with a mean of 24.8 ng l(-1). Liquid water content explained about 60% of the variability in Hg cloud concentrations. Highest Hg cloud water concentrations were found to be associated with transport from the Mid-Atlantic and Ohio River Valley, and lowest concentrations with transport from the north of Mt. Mansfield out of Canada. Twenty-nine event precipitation samples were collected during the ten-week cloud sampling period near the base of Mt. Mansfield as part of a long-term deposition study. The Hg concentrations of cloud water were similar to, but higher on average (median of 12.5 ng l(-1)) than Hg precipitation concentrations (median of 10.5 ng l(-1)). Cloud and precipitation samples were analyzed for fifteen trace elements including Mg, Cu, Zn, As, Cd and Pb by ICP-MS. Mean concentrations were higher in cloud water than precipitation for elements with predominately anthropogenic, but not crustal origin in samples from the same source region. One possible explanation is greater in-cloud scavenging of crustal elements in precipitating than non-precipitating clouds, and greater below-cloud scavenging of crustal than anthropogenic aerosols.