Global source-receptor relationships for mercury deposition under present-day and 2050 emissions scenarios.
Global source-receptor relationships for mercury deposition under present-day and 2050 emissions scenarios.
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DOI：
10.1021/es202496y
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发表时间：
2011-12-15
影响因子：
11.4
通讯作者：
Sunderland, Elsie M.
中科院分区：
文献类型：
--
作者：
Corbitt, Elizabeth S.;Jacob, Daniel J.;Holmes, Christopher D.;Streets, David G.;Sunderland, Elsie M.
要制定全球性的人为汞管制政策，就必须了解洲际范围内汞排放与汞沉积之间的关系。在这里，我们研究了源受体关系，目前的条件和四个2050年IPCC的情景，包括一系列的经济发展和环境监管的预测。我们使用GEOS-Chem全球模型来跟踪汞从其排放点到海洋和陆地表面水库中的快速循环，再到其在寿命较长的海洋和土壤池中的积累。沉积的汞有局部成分（排放的HgII，相对于沉积的寿命为3.7天）和全球成分（排放的Hg 0，相对于沉积的寿命为6个月）。通过HgII的光还原和Hg 0从表层储层（冰、陆地、表层海洋）的再排放，沉积汞的快速再循环可将人为汞的有效寿命延长至9个月，以防止遗留储层（土壤池和地下海洋）的损失。这个寿命仍然足够短，源-受体关系有一个强大的半球签名。亚洲的排放是所有海洋盆地人为沉积的最大来源，尽管逆风大陆也有区域来源的影响。目前，人类活动排放的汞仅占全球海洋汞沉积量的三分之一，其余部分来自自然和遗留来源。然而，对人为排放的控制将带来额外的好处，即减少重新排放到大气中的遗留汞。需要更好地了解汞从活性库向稳定的地球化学库转移的时间尺度。
Global policies regulating anthropogenic mercury require an understanding of the relationship between emitted and deposited mercury on intercontinental scales. Here we examine source-receptor relationships for present-day conditions and for four 2050 IPCC scenarios encompassing a range of economic development and environmental regulation projections. We use the GEOS-Chem global model to track mercury from its point of emission through rapid cycling in surface ocean and land reservoirs to its accumulation in longer-lived ocean and soil pools. Deposited mercury has a local component (emitted HgII, lifetime of 3.7 days against deposition) and a global component (emitted Hg0, lifetime of 6 months against deposition). Fast recycling of deposited mercury through photoreduction of HgII and re-emission of Hg0 from surface reservoirs (ice, land, surface ocean) increases the effective lifetime of anthropogenic mercury to 9 months against loss to legacy reservoirs (soil pools and the subsurface ocean). This lifetime is still sufficiently short that source-receptor relationships have a strong hemispheric signature. Asian emissions are the largest source of anthropogenic deposition to all ocean basins, though there is also regional source influence from upwind continents. Current anthropogenic emissions account for only about one-third of mercury deposition to the global ocean with the remainder from natural and legacy sources. However, controls on anthropogenic emissions would have the added benefit of reducing the legacy mercury re-emitted to the atmosphere. Better understanding is needed of the timescales for transfer of mercury from active pools to stable geochemical reservoirs.
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影响因子：
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作者：
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通讯作者：
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