Large scale mercury and trace element measurements in the Amazon basin
Large scale mercury and trace element measurements in the Amazon basin
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DOI：
10.1016/s1352-2310(00)00106-0
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发表时间：
2000-01-01
影响因子：
5
通讯作者：
Maenhaut, W
中科院分区：
文献类型：
--
作者：
Artaxo, P;de Campos, RC;Maenhaut, W
由于金矿开采活动，亚马逊流域出现大量汞排放。1995年8月和9月，作为“烟雾、云层和辐射 - 巴西（SCAR - B - Smoke Clouds and Radiation - Brazil）”实验的一部分，在亚马逊流域收集了汞和气溶胶粒子。使用三架飞机收集总汞和气溶胶粒子。采样是使用华盛顿大学的洛克希德C131A飞机以及两架巴西的EMB - 120“班德兰特”飞机进行的。大气汞的采样是在每条采样线上使用两个串联的金阱，并使用原子荧光光谱仪（AFS）进行测量。气溶胶收集在特氟龙和聚碳酸酯过滤器上，通过粒子诱导X射线发射（PIXE）分析多达20种元素，并通过仪器中子活化分析（INAA）分析多达39种元素。还测定了以黑碳（BC）表示的吸收性气溶胶以及气溶胶重量质量。采样时间为2 - 4小时。采样期处于生物质燃烧季节的高峰期，此时大部分汞被排放。本研究中总汞浓度高达14.8纳克/立方米。对合并的（气溶胶和汞）数据集进行了因子分析，观察到六个因子：一个土壤沙尘成分；一个生物质燃烧因子（具有细模态质量浓度、BC、钾、氯、锌等）；一个天然生物源成分（磷、钾、硫、钙、锰、锌）；第二个土壤沙尘因子（富含硅）；一个海盐气溶胶成分，含氯化钠；以及一个与金矿开采活动相关的因子，含汞、铅和其他元素。除了与金矿开采活动成分相关外，汞还明显与生物质燃烧成分相关。平均63%的汞浓度与金矿开采活动有关。约31%的汞浓度与生物质燃烧成分相关，土壤沙尘占空气中汞浓度的4%，氯化钠成分占2.1%。汞与生物质燃烧之间的高度关联可能是由至少三种机制引起的：（1）气态汞在现有的生物质燃烧颗粒上的吸附；（2）森林燃烧期间汞从植被直接释放到大气中；（3）森林燃烧期间汞从土壤中蒸发。三维远程气团轨迹分析表明，汞通过两条主要路线离开亚马逊流域的可能性：一条是通往南大西洋，另一条是越过安第斯山脉通往热带太平洋。（C）2000爱思唯尔科学有限公司。保留所有权利。
Large emissions of mercury (Hg) occur in the Amazon Basin as a result of gold mining activities. Mercury and aerosol particles were collected in the Amazon basin, as part of the SCAR-B-Smoke Clouds and Radiation - Brazil experiment in August and September 1995. Three airplanes were used to collect total mercury and aerosol particles. Sampling was performed with the University of Washington Lockheed C131A airplane, as well as in two Brazilian Bandeirante EMB 120 planes. Atmospheric mercury was sampled using two gold traps in series for each sampling line and measured with atomic fluorescence spectrometer (AFS). Aerosols were collected on Teflon and polycarbonate filters and analyzed by particle-induced X-ray emission (PIXE) for up to 20 elements, and by instrumental neutron activation analysis (INAA) for up to 39 elements. Absorbing aerosols expressed as black carbon (BC), and aerosol gravimetric mass were also determined. Sampling time was 2-4 h. The sampling period was at the peak of the biomass burning season, when most of the Hg is emitted. Concentrations for total Hg in this study were as high as 14.8 ng m(-3). Factor analysis was performed for the combined (aerosol and Hg) data set and six factors were observed: A soil dust component; a biomass-burning factor (with fine mode mass concentration, BC, K, Cl, Zn and others); a natural biogenic component (P, K, S, Ca, Mn, Zn); a second soil dust factor (enriched in Si); a sea-salt aerosol component, with NaCl; and a factor related to gold mining activities, with Hg, Pb and other elements. Hg was also clearly associated with the biomass-burning component, in addition to the gold mining activities component. An average of 63% of the Hg concentrations was associated with the gold mining activities. About 31% of the Hg concentration was associated with the biomass-burning component, the soil dust accounted for 4% and the NaCl component for 2.1% of the airborne Hg concentrations. The high association between Hg and biomass burning can be caused by at least three mechanisms: (1) adsorption of gaseous Hg on existing biomass burning particles; (2) direct release of Hg from the vegetation to the atmosphere during forest burning; (3) evaporation of Hg from soil during the forest burning. Three-dimensional long-range air mass trajectory analyses show the possibility that Hg exits the Amazon Basin over two main routes: to the South Atlantic, and to the Tropical Pacific, over the Andes. (C) 2000 Elsevier Science Ltd. All rights reserved.