Department of Renewable Resources, University of Alberta , 348B South Academic Building, Edmonton, Alberta T6G 2H1, Canada.
Department of Mathematical Sciences, University of Liverpool , Liverpool L69 3BX, United Kingdom.
Environ Sci Technol. 2017 Jun 6;51(11):6237-6249. doi: 10.1021/acs.est.6b04909. Epub 2017 May 25.
Peat cores were collected from five bogs in the vicinity of open pit mines and upgraders of the Athabasca Bituminous Sands, the largest reservoir of bitumen in the world. Frozen cores were sectioned into 1 cm slices, and trace metals determined in the ultraclean SWAMP lab using ICP-QMS. The uppermost sections of the cores were age-dated with Pb using ultralow background gamma spectrometry, and selected plant macrofossils dated using C. At each site, trace metal concentrations as well as enrichment factors (calculated relative to the corresponding element/Th ratio of the Upper Continental Crust) reveal maximum values 10 to 40 cm below the surface which shows that the zenith of atmospheric contamination occurred in the past. The age-depth relationships show that atmospheric contamination by trace metals (Ag, Cd, Sb, Tl, but also V, Ni, and Mo which are enriched in bitumen) has been declining in northern Alberta for decades. In fact, the greatest contemporary enrichments of Ag, Cd, Sb, and Tl (in the top layers of the peat cores) are found at the control site (Utikuma) which is 264 km SW, suggesting that long-range atmospheric transport from other sources must be duly considered in any source assessment.
从世界上最大的沥青储量阿萨巴斯卡沥青砂附近的五个沼泽地中采集了泥炭芯。将冷冻的岩芯切成 1 厘米的薄片，并在超净 SWAMP 实验室中使用 ICP-QMS 测定痕量金属。使用超低背景伽马能谱法对岩芯的最上层进行铅定年，并使用 C 对选定的植物大化石进行定年。在每个地点，痕量金属浓度以及富集因子（相对于上地壳相应元素/Th 比值计算）均显示出地表以下 10 至 40 厘米处的最大值，这表明大气污染的高峰期发生在过去。年龄-深度关系表明，在过去几十年中，阿尔伯塔省北部的大气中痕量金属（银、镉、锑、铊，以及在沥青中富集的钒、镍和钼）的污染一直在减少。事实上，在距离 264 公里的西南部的对照点（Utikuma）发现了泥炭芯顶部中银、镉、锑和铊的最大当代富集，这表明必须充分考虑来自其他来源的长距离大气传输，才能进行任何来源评估。
