Climate Change Institute, University of Maine, Orono, Maine 04469-5790, USA.
Environ Sci Technol. 2012 Nov 6;46(21):11710-7. doi: 10.1021/es302138n. Epub 2012 Oct 19.
Between 45,000 cal years BP and the beginning of the Holocene, the accumulation rate for Hg in sediments of Lake Tulane, Florida ranged from ≈2 to 10 μg m(-2) yr(-1), compared with 53 μg Hg m(-2) yr(-1) in the 1985-1990 period of anthropogenic input. The locality experienced regional draw-down of the water table during the Wisconsinan glaciation, which lowered global sea level by nearly 130 m. Natural atmospheric deposition of Hg to the surrounding area resulted in long-term (ca. 100,000 years) sequestration of this atmospheric flux of Hg, primarily by adsorption in the oxic Al- and Fe-hydroxide-rich sandy subsoil. Global sea level rise during deglaciation led to a rising regional water table, flooding the oxidized soils surrounding Tulane. Iron and adsorbed Hg were mobilized by reductive dissolution and transported by groundwater flow to Lake Tulane and ultimately to the accumulating sediment. The accumulation rate of Hg (and Fe) increased rapidly about 16,000 cal years BP, peaked at nearly 60 μg Hg m(-2) yr(-1) ca. 13,000-14,000 cal years BP, declined sharply during the Younger Dryas, and then increased sharply to a second 60 μg Hg m(-2) yr(-1) peak about 5000 cal years BP. Thereafter, it declined nearly to background by 900 cal years BP. In similar geologic situations, rapid modern sea level rise will initiate this process globally, and may mobilize large accumulations of Hg and lesser amounts of As, and other redox sensitive metals to groundwater and surface water.
在 45000 年前的全新世开始之前，佛罗里达州图兰湖沉积物中汞的积累速率约为 2 至 10μg m(-2) yr(-1)，而在 1985 年至 1990 年人为汞输入期间为 53μg Hg m(-2) yr(-1)。该地点在威斯康星冰期经历了区域性地下水位下降，导致全球海平面下降近 130 米。汞通过大气自然沉积到周围地区，导致这种大气汞通量的长期（约 10 万年）封存，主要通过氧化带中富含 Al 和 Fe 的氢氧化物的吸附来实现。冰消期的全球海平面上升导致区域性地下水位上升，淹没了图兰周围的氧化土壤。铁和吸附的汞通过还原溶解而被迁移，并随地下水流动被运移到图兰湖，最终进入积累的沉积物中。汞（和铁）的积累速率在大约 16000 年前迅速增加，在大约 13000 至 14000 年前达到近 60μg Hg m(-2) yr(-1)的峰值，在新仙女木期急剧下降，然后在大约 5000 年前再次急剧增加到第二个 60μg Hg m(-2) yr(-1)的峰值。此后，它在 900 年前的 BP 左右几乎降至背景水平。在类似的地质情况下，快速的现代海平面上升将在全球范围内启动这一过程，并可能使大量汞和少量砷以及其他氧化还原敏感金属迁移到地下水和地表水。
