Mercury exports from a High-Arctic river basin in Northeast Greenland (74°N) largely controlled by glacial lake outburst floods
Mercury exports from a High-Arctic river basin in Northeast Greenland (74°N) largely controlled by glacial lake outburst floods
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DOI：
10.1016/j.scitotenv.2015.01.097
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发表时间：
2015-05-01
影响因子：
9.8
通讯作者：
Riget, Frank
中科院分区：
文献类型：
--
作者：
Sondergaard, Jens;Tamstorf, Mikkel;Riget, Frank
研究了2009-2013年期间格陵兰东北部Zackenberg河流域（ZRB）的河流汞（Hg）输出动态。溶解和沉积物结合的汞定期测量在Zackenberg河的整个时期与流水（6月至10月），并耦合到水排放测量。此外，还对一些雪、土壤和永久冻土样品进行了汞分析。河水中溶解汞和沉积物结合汞的平均浓度（+/- SD）分别为0.39 +/- 0.13和5.5 +/- 1.4 ng L-1，河流沉积物中汞的平均浓度为0.033 +/- 0.025 mg kg（-1）。河流汞的时间变化主要与融雪，突发侵蚀事件，并从冰川堰塞湖的ZRB的上部爆发洪水。514 km（2）ZRB的年汞出口量从0.71千克到>1.57千克不等，大部分（86-96%）与沉积物结合汞有关。ZRB的汞排放量为1.4-3.1克汞/公里/年，是北极河流流域报告的最高排放量之一。从ZRB河流出口的汞被认为是在很大程度上控制的频率，规模和时间的冰川湖溃决洪水，发生在四个五年的7月至8月。洪水占年水排放量的5%至>10%，占年汞输出量的31%以上。此外，冬季降雪量和夏季温度被认为是重要的间接控制每年的汞输出。冰湖溃决洪水的发生和时间在ZRB在夏末最大的土壤解冻深度，在上ZRB的冰川的位置，并在Zackenberg的永久冻土融化，近年来导致河岸不稳定的时间被认为是解释在这个地区的洪水控制的汞出口的高比例的核心因素。(C)2015 Elsevier B. V.版权所有。
Riverine mercury (Hg) export dynamics from the Zackenberg River Basin (ZRB) in Northeast Greenland were studied for the period 2009-2013. Dissolved and sediment-bound Hg was measured regularly in the Zackenberg River throughout the periods with running water (June-October) and coupled to water discharge measurements. Also, a few samples of snow, soil, and permafrost were analysed for Hg. Mean concentrations of dissolved and sediment-bound Hg in the river water (+/- SD) were 039 +/- 0.13 and 5.5 +/- 1.4 ng L-1, respectively, and mean concentrations of Hg in the river sediment were 0.033 +/- 0.025 mg kg(-1). Temporal variations in river Hg were mainly associated with snowmelt, sudden erosion events, and outburst floods from a glacier-dammed lake in the upper part of the ZRB. Annual Hg exports from the 514 km(2) ZRB varied from 0.71 to >1.57 kg and the majority (86-96%) was associated with sediment-bound Hg. Hg yields from the ZRB varied from 1.4-3.1 g Hg km(-2) yr(-1) and were among the highest yields reported from Arctic river basins. River exports of Hg from ZRB were found to be largely controlled by the frequency, magnitude and timing of the glacial lake outburst floods, which occurred in four of the five years in July-August. Floods accounted for 5 to >10% of the annual water discharge, and up to >31% of the annual Hg export. Also, the winter snowfall and the summer temperatures were found to be important indirect controls on the annual Hg export. The occurrence and timing of glacial lake outburst floods in the ZRB in late summer at the time of maximum soil thaw depth, the location of the glacier in the upper ZRB, and increased thawing of the permafrost in Zackenberg in recent years leading to destabilisation of river banks are considered central factors explaining the high fraction of flood-controlled Hg export in this area. (C) 2015 Elsevier B.V. All rights reserved.