Couto J A, Fernández J A, Aboal J R, Carballeira A
Ecología, Facultad de Biología, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain.
Sci Total Environ. 2004 May 25;324(1-3):211-22. doi: 10.1016/j.scitotenv.2003.10.024.
Moss (Scleropodium purum) transplants were used to study bioconcentration originating from dry and bulk deposition, by measuring the tissue contents of Al, As, Ca, Cu, Fe, Hg, Mn, Ni, Pb, Se and Zn. Furthermore, a laboratory experiment was carried out to determine the sequence of maximum concentration and affinity of Al, Cu, Fe, Hg, Ni, Pb and Zn, in S. purum. We found that in many of the transplants, for the same period of exposure, higher levels of metals were accumulated via dry deposition than via bulk deposition. This result may be explained by the simple washing action of the rain on the surface of the moss, and by the existence of processes that provoke the loss of some of the accumulated elements: intercationic displacement and leaching caused by acid precipitation. Modelling of the final bioconcentration observed, as a balance of inputs and outputs of elements, revealed that this terrestrial moss does not integrate, but rather concentrates atmospheric deposition, and there exists a state of unstable equilibrium between inputs and outputs of elements, a state that is determined by the characteristics of the surrounding environment. On the basis of the results obtained in this study, we can conclude that at present, it is not possible to extrapolate the calibrations between the concentrations of elements accumulated in a certain species of moss to values of atmospheric deposition (bulk deposition) from one place to another with different environmental conditions.
通过测量铝、砷、钙、铜、铁、汞、锰、镍、铅、硒和锌的组织含量，利用苔藓（硬叶藓）移植来研究源于干沉降和湿沉降的生物富集。此外，还进行了一项实验室实验，以确定硬叶藓中铝、铜、铁、汞、镍、铅和锌的最大富集浓度顺序和亲和力。我们发现，在许多移植实验中，在相同的暴露时间段内，通过干沉降积累的金属水平高于通过湿沉降积累的金属水平。这一结果可以通过雨水对苔藓表面的简单冲洗作用，以及存在导致一些积累元素损失的过程来解释：酸沉降引起的阳离子置换和淋溶。对最终观察到的生物富集进行建模，将其作为元素输入和输出的平衡，结果表明这种陆生苔藓并非整合大气沉降，而是富集大气沉降，并且在元素的输入和输出之间存在一种不稳定的平衡状态，这种状态由周围环境的特征决定。基于本研究获得的结果，我们可以得出结论，目前，不可能将某一苔藓物种中积累的元素浓度之间的校准值外推到不同环境条件下另一个地方的大气沉降（湿沉降）值。
