The trace metal chemistry of atmospheric dry deposition samples collected at Cap Ferrat: a coastal site in the Western Mediterranean
The trace metal chemistry of atmospheric dry deposition samples collected at Cap Ferrat: a coastal site in the Western Mediterranean
复制标题
DOI：
10.1016/s0304-4203(99)00062-6
复制
发表时间：
1999-12-01
期刊：
影响因子：
3
通讯作者：
Preston, MR
中科院分区：
文献类型：
--
作者：
Chester, R;Nimmo, M;Preston, MR
在西地中海海岸的Cap Ferret，在一个替代板上收集了一系列10个干沉积样品，为期8个月，并分析了Al，Fe，Mn，Ni，Co，Cr，Cu，Zn和ph。文献中可获得的痕量金属干沉积数据相对较少，并且在使用替代板收集干沉积物时存在相当大的困难。然而，微量金属化学板收集干沉积在Cap Ferrat网站一般模仿的趋势，从理论上的金属沉积速度预测。干沉积主要由较大颗粒的沉降物组成，在母气溶胶->干沉积序列中，以地壳为主的非富集元素（NEE）与以陆源物质为主的非富集元素（AEE）之间存在强烈的、颗粒大小介导的分馏作用，后者在干沉积中被贫化。因此，尽管干沉降中的AEEs相对于平均地壳物质仍然富集，但干沉降和母体气溶胶具有不同的“化学特征”。此外，干沉积物比母体气溶胶具有更均匀的微量金属成分。相对于母体气溶胶，干沉积物中AEEs的消耗对海水溶解具有重要意义。为了评估这一点，概述了一种技术，它允许铜，锌和铅的溶解度估计的基础上，他们的EF，，在大气颗粒物中的值。该技术表明，铜，锌和铅的溶解度从干沉降小于那些将从母气溶胶的数据预测。干和湿微量金属沉积通量之间的比较在帽貂网站显示，颗粒部分占主导地位的所有金属的干沉积。而在湿沉降过程中，Cu和Pb的形态发生了转换，可溶态占主导地位. (C)1999 Elsevier Science B. V.保留所有权利。
A series of 10 dry deposition samples were collected on a surrogate plate over a period of 8 months at Cap Ferret, a site on the Western Mediterranean coast, and analysed for Al, Fe, Mn, Ni, Co, Cr, Cu, Zn and ph. Relatively few data sets for trace metal dry deposition are available in the literature, and considerable difficulties are inherent in the use of surrogate plates for the collection of dry deposition. However, the trace metal chemistry of the plate-collected dry deposition at the Cap Ferrat site generally mimics the trends predicted from theoretical metal deposition velocities. The dry deposition is dominated by the fall-out of larger-size particles and during the parent aerosol --> dry deposition sequence there is a strong, particle size-mediated, fractionation of the crust-dominated, non-enriched elements (NEEs) from the anthropogenic-dominated, anomalously enriched elements (AEEs), with the latter being depleted in the dry deposition. As a result, although the AEEs in the dry deposition are still enriched relative to average crustal material, the dry deposition and the parent aerosols have different 'chemical characters'. Further, the dry deposition has a more homogenous trace metal composition than the parent aerosol. The depletion of the AEEs in the dry deposition, relative to the parent aerosol, has important implications for sea water solubilisation. To assess this, a technique is outlined which allows the solubilities of Cu, Zn and Pb to be estimated on the basis of their EF,,, values in atmospheric particulates. The technique reveals that the solubilities of Cu, Zn and Pb from the dry deposition are less than those which would be predicted from data on the parent aerosol. A comparison between the dry and wet trace metal deposition fluxes at the Cap Ferret site shows that the particulate fraction dominates the dry deposition of all the metals. However, in wet deposition Cu and Pb switch character and the soluble fraction becomes dominant. (C) 1999 Elsevier Science B.V. All rights reserved.