Using lake sediment mercury flux ratios to evaluate the regional and continental dimensions of mercury deposition in arctic and boreal ecosystems
Using lake sediment mercury flux ratios to evaluate the regional and continental dimensions of mercury deposition in arctic and boreal ecosystems
复制标题
利用湖泊沉积物汞通量比来评估北极和北方生态系统中汞沉积的区域和大陆规模
DOI：
10.1016/s1352-2310(97)00116-7
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发表时间：
1998
影响因子：
5
通讯作者：
W. L. Lockhart
中科院分区：
文献类型：
--
作者：
D. Landers;C. Gubala;M. Verta;M. Lucotte;K. Johansson;T. Vlasova;W. L. Lockhart
北极和亚北极生态系统中人为升高的汞沉积是一个潜在的严重环境问题，特别是在北欧和北美。为了确定这一问题的严重程度，有必要在广泛的空间尺度上进行评估。在没有建立Hg沉降大气监测站网络的情况下，我们利用整个北极和亚北极湖泊沉积物剖面的沉积物通量比来评估流域汞通量的时空格局。本文分析了芬兰、瑞典、加拿大、美国和俄罗斯的210pb年代沉积物岩心层中总汞的质量累积，构建了通量比。通量比的计算方法是用最近（即最近~ 10-40年）或工业时代的平均汞通量除以工业前的平均汞通量值。结果在北半球的北极地区差别很大。通量比最高的是与大气汞排放强区域源相关的区域，如北美中部和东部以及中欧。美国北极地区和俄罗斯泰米尔半岛的湖泊在背景通量上只显示出轻微的（~ 30%）富集。根据流域地质性质的不同，背景汞通量存在很大差异，阿拉斯加的一些湖泊显示出相对高浓度的沉积物汞，但没有人为富集的证据。在北美，汞通量比有向东南方向朝着大陆排放源（燃煤电厂、氯碱厂、金属冶炼厂和废物焚烧厂）最集中的方向增加的趋势。在北欧（瑞典和芬兰），汞通量比在南北方向呈增加趋势。我们的研究结果表明，在一些北方地区，人为汞沉积是主要的区域汞沉积过程，但在远离城市/工业汞排放的景观中，其重要性较低。
Anthropogenically elevated Hg deposition in arctic and subarctic ecosystems is potentially a serious environmental problem, particularly in northern Europe and North America. To determine the magnitude of this concern, it is necessary to make an evaluation over a broad spatial scale. In the absence of an established network of atmospheric monitoring stations for Hg deposition, we have utilized sediment flux ratios derived from lake sediment profiles throughout the arctic and subarctic to evaluate spatial and temporal patterns of Hg flux to watersheds. Total Hg mass accumulations in layers of210Pb dated sediment cores collected from Finland, Sweden, Canada, U.S.A. and Russia were analyzed to construct flux ratios. Flux ratios are calculated by dividing the average recent (i.e. last ∼ 10–40 yr) or industrial era Hg flux by an average pre-industrial Hg flux value. Results differ widely across the arctic regions of the northern hemisphere. The highest flux ratios were found in regions associated with strong regional sources of atmospheric Hg emissions such as central and eastern North America and Central Europe. Lakes throughout the U.S. Arctic and the Taimyr Peninsula of Russia showed only slight (∼30%) enrichment over background fluxes. Large differences existed in background Hg flux depending on the nature of the watershed geology with some lakes in Alaska exhibiting relatively high concentrations of sediment Hg without evidence of anthropogenic enrichment. In North America, there is a tendency for Hg flux ratios to increase in an southeasterly direction toward the highest concentration of continental emission sources (coal fired power plants, Chlor-alkali plants, metal smelters and waste incinerators). In northern Europe (Sweden and Finland) there is a trend of increasing Hg flux ratios in the north to south direction. Our results suggest that anthropogenic Hg deposition is the dominant regional mercury deposition process in some northern regions but of lesser importance in landscapes highly remote from urban/industrial Hg emissions.