Lawson Sean T, Scherbatskoy Timothy D, Malcolm Elizabeth G, Keeler Gerald J
University of Vermont, Burlington, VT, USA.
J Environ Monit. 2003 Aug;5(4):578-83. doi: 10.1039/b210125d.
As part of the Lake Champlain Basin watershed study of mercury (Hg) and pollutant deposition, cloud water and cloud throughfall collections were conducted at the south summit (1204 m) of Mt. Mansfield, Vermont between August 1 and October 31, 1998, for multi-element chemical analysis. A passive Teflon string collector was deployed during non-precipitating events to sample cloud/fog water at timberline, while three sets of paired funnels collected cloud throughfall under the red spruce-balsam fir canopy. Samples were analyzed for concentrations of Hg, major ions, and 10 trace elements. Ultra-clean sampling and analysis techniques were utilized throughout the study. Six events were sampled for cloud water alone and four events were sampled for both cloud water and cloud throughfall. Cloud throughfall chemistry showed substantial modification from incident cloud water. Much higher concentrations of Hg (2.3 x), base cations (Ca2+, K-, Mg2+; 3-18 x) and certain trace elements (Ni, Cu, Mn, Rb, Sr; 2-34 x) were observed in throughfall than in cloud water. These results confirm that cloud water can leach a wide variety of elements from tree foliage and wash off dry deposited elements. Cloud water deposited an average of 0.42 +/- 0.12 mm of water per hour. Estimated cloud water deposition of Hg was 7.4 microg m(-2) for the period August 1-October 31, approximately twice that deposited by rain during this period at a nearby low elevation Hg monitoring site. Our results indicate that cloud water and Hg deposition at Mt. Mansfield are likely to have considerable ecological effects.
作为尚普兰湖流域汞（Hg）及污染物沉降研究的一部分，于1998年8月1日至10月31日期间，在佛蒙特州曼斯菲尔德山的南峰（海拔1204米）进行了云水和云穿透水的采集，用于多元素化学分析。在无降水事件期间，部署了一个被动式聚四氟乙烯绳状收集器，以在树线处采集云/雾水，同时在红云杉-香脂冷杉树冠下，用三组配对漏斗收集云穿透水。分析了样品中汞、主要离子和10种微量元素的浓度。在整个研究过程中采用了超洁净采样和分析技术。单独对6次事件的云水进行了采样，对4次事件的云水和云穿透水都进行了采样。云穿透水化学显示，与入射云水相比有显著变化。在穿透水中观测到的汞（2.3倍）、碱性阳离子（Ca2+、K+、Mg2+；3 - 18倍）和某些微量元素（Ni、Cu、Mn、Rb、Sr；2 - 34倍）的浓度比云水中高得多。这些结果证实，云水可以从树叶中淋溶出多种元素，并冲刷掉干沉降元素。云水每小时平均沉积0.42±0.12毫米的水。8月1日至10月31日期间，估计云水汞沉积量为7.4微克/平方米，约为附近低海拔汞监测点同期降雨汞沉积量的两倍。我们的结果表明，曼斯菲尔德山的云水和汞沉积可能具有相当大的生态影响。
