彭佳屿岛春季TSP中痕量金属组成及其来源解析

摘要

Trace metal compositions of marine aerosol were modified significantly by the addition of anthropogenic and terrestrial materials during transport via the atmospheric circulation from land to the ocean. To explore the metal effect of atmospheric deposition on marine ecosystem,field observations of trace metals in marine aerosol are necessary. However, due to logistic difficulties, rare studies were carried out on islands in the open ocean. In this study,60 total suspended particulates(TSP) samples were collected from March to May in 2010 at the Pengjia Islet to the north of Taiwan,China. Concentrations of trace metals(Al,Fe,Ti,Y,Mn,Ba,Sr,Co,Cr,V,Ni, Tl,Zn,Sn,Pb,As,Cd,Sb and Se) were analyzed by ICP-MS.Together with the concentration of Al,the air mass backward trajectories and the Lidar browse images by CALIPSO from the National Aeronautics and Space Administration (NASA), were allowed to divide samples into non-dust TSP and dust TSP. Trace metals in dust TSP were higher in concentration than those in non-dust TSP, suggesting that dust was a good carrier to bring trace metals to the open ocean. Using the enrichment factor, correlation analysis and the model of positive matrix factorization,we found that Al,Fe,Ti and Y in non-dust TSP were mainly sourced from the crust,while Mn,Ba,Sr,Co and Cr originated from both the crust and anthropogenic sources. As for the dust TSP, Al, Fe, Ti, Y, Mn, Ba, Sr, Co and Cr were dominantly from the crust.Fossil fuel combustion contributed to V and Ni in non-dust TSP,but for the dust TSP,the crust involved.There were similar sources for Tl,Zn,As,Sn,Pb,Cd,Sb and Se both in non-dust TSP and dust TSP. Tl were dominantly sourced from the vehicle and coal combustion,and Zn, As, Sn, Pb, Cd and Sb originated from vehicle, coal and oil combustion, and Se was from the fossil fuel combustion. Trace metals,such as Tl,Zn,As,Sn,Pb,Cd,Sb and Se,associated with anthropogenic activities can be long-range transported to the open ocean.%通过大气环流向海洋大气边界层传输的人为源和陆源物质,明显改变了海洋气溶胶中痕量金属的组成.但基于开阔海域岛屿连续观测研究海洋气溶胶中痕量金属元素组成及其来源的研究较少.2010年3—5月在我国台湾北部东海海域彭佳屿岛采集了60个TSP(总悬浮颗粒物)样品,采用电感耦合等离子体质谱仪(ICP-MS)分析了19种痕量金属(Al、Fe、Ti、Y、Mn、Ba、Sr、Co、Cr、V、Ni、Tl、Zn、Sn、Pb、As、Cd、Sb、Se)的质量浓度.基于TSP中Al浓度、气团后向轨迹分析和美国国家宇航局CALIPSO卫星星载激光雷达扫描图像,将采集的TSP分为非沙尘TSP(不受沙尘影响的TSP)和沙尘TSP(受沙尘影响的TSP).沙尘TSP中所有痕量金属的浓度都高于非沙尘TSP,表明沙尘对彭佳屿岛TSP中痕量金属有贡献.结合富集因子、相关性分析和PMF模型研究结果表明,彭佳屿岛春季非沙尘TSP中Al、Fe、Ti和Y主要来源于地壳矿物,Mn、Ba、Sr、Co和Cr同时受地壳矿物和人为源的影响;沙尘TSP中Al、Fe、Ti、Y、Mn、Ba、Sr、Co和Cr主要来源于地壳矿物.V和Ni在彭佳屿岛春季非沙尘TSP中主要来源于燃料油燃烧,而在沙尘TSP中同时受燃料油燃烧和地壳矿物的影响.非沙尘TSP和沙尘TSP中,Tl、Zn、As、Sn、Pb、Cd、Sb和Se的来源相似.Tl主要源于交通和煤燃烧,Zn、Sn、Pb、Cd和Sb同时来源于交通、煤和燃料油燃烧,As主要来源于煤燃烧,Se则主要来源于煤和燃料油燃烧.研究显示,人为源释放到大气中的Tl、Zn、As、Sn、Pb、Cd、Sb和Se可以通过大气环流长距离传输至开阔海域.