Abstract：
The remoteness and low population in the Arctic allow us to study global environmental processes, where the analysis of indicators can provide useful information about local and distant pollution sources. Fresh snow represents a convenient indicator of regional and transboundary atmospheric contamination sources, entrapping aerosols, and particulates like a natural autosampler of the environment. Lead stable isotopes are widely used to trace and monitor local and distant pollution sources. However, the behavior of Pb within different snow components is still not thoroughly studied, and its significance could be underestimated if only larger particulates are accounted for. We collected snow and samples from potential sources (fuel, rocks, coal) in three Arctic localities: Nuuk (Greenland), Reykjavik (Iceland), and Longyearbyen (Svalbard). We separated the filtrate from the filter residue through 0.45 μm nitrocellulose membranes to isolate the low-diameter particles associated with long-range transport from larger particles of mostly local natural origin. Filtrates yielded higher EFs (enrichment factor as the Pb/Al ratio relative to the upper crust) than filtration residues (80 ± 104 and 2.1 ± 1.1, respectively), and Pb isotope signals similar to fuel and coal (206Pb/207Pb are 1.199 ± 0.028 in coal, 1.168 ± 0.029 in filtrates, 1.163 ± 0.013 in fuel, 1.137 ± 0.045 in residues, and 0.985 ± 0.020 in rocks). In contrast to filtrates, the filter residues present wider ranges of Pb isotope compositions and crustal contributions and lower EFs, so we suggest that filtrate contains Pb from fuel combustion more selectively, while the residue carries a more considerable contribution of local mineral dust that can mask the contribution of other anthropogenic or distant natural sources. These findings add weight to the notion that filtrates are a more selective measure of metal deposition from long-range anthropogenic emissions compared to analyzing bulk melted snow or only filter residues.
摘要：
北极的偏远和低人口使我们能够研究全球环境过程，指标分析可以提供有关本地和远处污染源的有用信息。新鲜的雪代表了区域和跨界大气污染源的方便指标，截留气溶胶，和像环境的天然自动进样器一样的微粒。铅稳定同位素广泛用于跟踪和监测当地和远处的污染源。然而,铅在不同积雪成分中的行为仍未得到深入研究，如果只考虑较大的颗粒物，其重要性可能会被低估。我们从潜在来源（燃料，岩石,煤炭)在三个北极地区：努克(格陵兰)，雷克雅未克(冰岛),和朗伊尔比（斯瓦尔巴群岛）。我们通过0.45μm硝化纤维素膜将滤液与滤渣分离，以将与远距离运输相关的小直径颗粒与大多数本地天然来源的较大颗粒分离。滤液比过滤残留物（分别为80±104和2.1±1.1）产生更高的EF（富集系数为相对于上地壳的Pb/Al比），与燃料和煤相似的Pb同位素信号（煤中206Pb/207Pb为1.199±0.028，1.168±0.029英寸滤液，1.163±0.013英寸燃油，1.137±0.045的残留物，和0.985±0.020的岩石）。与滤液相反，过滤残留物呈现更宽范围的Pb同位素组成和地壳贡献和更低的EF，所以我们建议滤液更有选择性地含有燃料燃烧中的铅，而残留物携带更多的当地矿物粉尘，可以掩盖其他人为或遥远的自然来源的贡献。这些发现增加了这样一种观念，即与分析大量融化的雪或仅过滤残留物相比，滤液是远距离人为排放的金属沉积的更有选择性的量度。
