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首页> 外文期刊>Environmental Science & Technology >Response of a Macrotidal Estuary to Changes in Anthropogenic Mercury Loading between 1850 and 2000
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Response of a Macrotidal Estuary to Changes in Anthropogenic Mercury Loading between 1850 and 2000

机译：潮汐河口对1850至2000年间人为汞负荷变化的响应

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Methylmercury (MeHg) bioaccumulation in marine food webs poses risks to fish-consuming populations and wildlife. Here we develop and test an estuarine mercury cycling model for a coastal embayment of the Bay of Fundy, Canada. Mass budget calculations reveal that MeHg fluxes into sediments from settling solids exceed losses from sediment-to-water diffusion and resuspension. Although measured methylation rates in berrthic sediments are high, rapid demethyiaton results in negligible net in situ production of MeHg. These results suggest that inflowing fluvial and tidal waters, rather than coastal sediments, are the dominant MeHg sources for pelagic marine food webs in this region. Model simulations show water column MeHg concentrations peaked in the 1960s and declined by almost 40% by the year 2000. Water column MeHg concentrations respond rapidly to changes in mercury inputs, reaching 95% of steady state in approximately 2 months. Thus, MeHg concentrations in pelagic organisms can be expected to respond rapidly to mercury loading reductions achieved through regulatory controls. In contrast, MeHg concentrations in sediments have steadily increased since the onset of industrialization despite recent decreases in total mercury loading. Bentfiic food web MeHg concentrations are likely to continue to increase over the next several decades at present-day mercury emissions levels because the deep active sediment layer in this system contains a large amount of legacy mercury and requires hundreds of years to reach steady state with inputs.
机译：海洋食物网中甲基汞（MeHg）的生物蓄积给鱼类消费人口和野生生物带来了风险。在这里，我们开发并测试了加拿大芬迪湾沿海沿岸河口汞循环模型。大量预算计算表明，沉淀下来的固体中的MeHg通量超过了沉积物向水的扩散和再悬浮所造成的损失。尽管在残生沉积物中测得的甲基化率很高，但快速的脱甲基作用导致MeHg的净原位净生成量可忽略不计。这些结果表明，流入河流和潮汐水而不是沿海沉积物是该地区中上层海洋食物网的主要MeHg来源。模型模拟显示，水柱中的MeHg浓度在1960年代达到峰值，到2000年下降了近40％。水柱中的MeHg浓度对汞输入的变化迅速做出反应，在大约2个月内达到稳态的95％。因此，可以预期中上层生物体中的MeHg浓度对通过监管控制措施实现的汞负荷减少迅速做出反应。相反，自从工业化开始以来，尽管总汞负荷最近有所减少，但沉积物中的MeHg浓度却稳定增加。在当前的汞排放水平下，Bentfiic食物网的MeHg浓度在未来几十年内可能会继续增加，因为该系统中的深层活动沉积物层含有大量的遗留汞，需要数百年才能达到稳定状态。

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  • 来源
    《Environmental Science & Technology》 |2010年第5期|p.1698-1704|共7页
  • 作者

    ELSIE M. SUNDERLAND; JOHN DALZIEL; ANDREW HEYES; BRIAN A. BRANFIREUN; DAVID P. KRABBENHOFT; FRANK A.P.C. GOBAS;

  • 作者单位

    School of Engineering and Applied Sciences, Harvard University, Cambridge Massachusetts 02138, Meteorological Service of Canada;

    rnEnvironment Canada, 45 Alderney Drive, Dartmouth, Nova Scotia, B2Y 2N6, Canada;

    Chesapeake Biological Laboratory, University of Maryland Center for Environmental Science, University System of Maryland, Solomons, Maryland 20688;

    rnDepartment of Geography, University of Toronto at Mississauga, 3359 Mississauga Road North, Mississauga, Ontario, L5L 1C6, Canada;

    rnU.S. Geological Survey, 8505 Research Way, Middleton, Wisconsin 53562;

    rnSchool of Resource and Environmental Management, Simon Fraser University, Bumaby, British Columbia, V5A 1S6, Canada;

  • 收录信息 美国《科学引文索引》(SCI);美国《工程索引》(EI);美国《生物学医学文摘》(MEDLINE);美国《化学文摘》(CA);
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