Tracing anthropogenic Hg and Pb input using stable Hg and Pb isotope ratios in sediments of the cent
Tracing anthropogenic Hg and Pb input using stable Hg and Pb isotope ratios in sediments of the cent
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DOI：
10.1016/j.chemgeo.2012.02.018
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发表时间：
2013-01
期刊：
影响因子：
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通讯作者：
M. Mil-Homens;J. R. Blum;J. Canário;M. Caetano;A. M. Costa;S. Lebreiro;M. Trancoso;T. Richter
中科院分区：
文献类型：
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作者：
M. Mil-Homens;J. R. Blum;J. Canário;M. Caetano;A. M. Costa;S. Lebreiro;M. Trancoso;T. Richter
三个短的海洋沉积物岩心从卡斯凯海底峡谷（CSC;核心252-32和252-35）和葡萄牙中部边缘的埃斯特雷马杜拉支线（核心252-16）进行了分析，汞，铅，铝，锰浓度，铅和汞的稳定同位素组成，以重建的趋势，汞和铅的来源和积累。沉积物年龄的测定基于210 Pb测量。研究的核心揭示了增加汞和铅的浓度，独立的粒度变化，自19世纪中期世纪对本。与此同时，206 Pb/207 Pb的下降趋势，以更少的放射性成因的值向地面被发现，表明增加人为输入。δ 202 Hg的最低值通常出现在较老的沉积物中，其特征是Hg和Pb浓度较低，表明人为金属的输入量较低。252-16柱样中的奇数质量数（199 Hg和201 Hg）Hg同位素具有正质量独立分馏（MIF）特征，而252-32和252-35柱样中的近代沉积物没有显示出明显的MIF，这可能反映了该柱样靠近人为Hg污染源（塔霍河口）以及CSC作为颗粒载体的重要性。多示踪剂的方法，稳定的汞和铅同位素的基础上，确认人为的汞和铅富集在最近的海洋沉积物，也使我们能够区分为主的碎屑（如CSC）与半远洋（埃斯特雷马杜拉支线）沉积区。
Three short marine sediment cores from the Cascais Submarine Canyon (CSC; cores 252-32 and 252-35) and the Estremadura Spur (core 252-16) on the central Portuguese Margin were analysed for Hg, Pb, Al, and Mn concentrations, and both Pb and Hg stable isotope compositions, in order to reconstruct trends in Hg and Pb sources and accumulation. Sediment ages were determined based on210Pb measurements. The studied cores reveal increasing Hg and Pb concentration, independent of grain-size variations, since the middle of the 19th century towards the Present. Concomitantly, a decreasing trend of206Pb/207Pb to less radiogenic values towards the surface was found, indicating increasing anthropogenic inputs. The lowest values of δ202Hg were generally observed in the older sediments characterized by low Hg and Pb concentrations, suggesting a low input of anthropogenic metals. Odd mass number (199Hg and201Hg) Hg isotopes in sediment samples from core 252-16 were characterized by positive mass independent fractionation (MIF), while recent sediments from cores 252-32 and 252-35 did not reveal significant MIF, probably reflecting both the proximity to the source of anthropogenic Hg contamination (Tagus Estuary) and the importance of the CSC as a particle carrier. The multi-tracer approach, based on both stable Hg and Pb isotopic signatures, confirms anthropogenic Hg and Pb enrichment in recent marine sediments and also allows us to distinguish between areas dominated by detrital (e.g. CSC) versus hemipelagic (Estremadura Spur) sedimentation.