Influence of metal speciation in natural freshwater on bioaccumulation of copper and zinc in periphyton: a microcosm study.
Influence of metal speciation in natural freshwater on bioaccumulation of copper and zinc in periphyton: a microcosm study.
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天然淡水中金属形态对附生生物中铜和锌生物富集的影响：微观研究。
DOI：
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发表时间：
2004
影响因子：
11.4
通讯作者：
L. Sigg
中科院分区：
文献类型：
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作者：
S. Meylan;R. Behra;L. Sigg
许多痕量金属的自由离子活度模型(FIAM)已经在实验室条件下得到了证实，但在天然有机配体的存在影响金属形态和生物有效性的自然条件下仍有待验证。这项研究的目的是通过测量铜和锌的形态以及围生植物中的金属积累来测试在自然条件下是否遵循FIAM。微观世界中的附生植物暴露在天然河水中，添加不同浓度的铜(25-258 NM)或锌(18-501 NM)以及添加合成配体(NTA)。用竞争配体交换结合阴/阳极溶出伏安法测定，游离Cu2+在10(-16.5)-10(-14.5)M范围内，锌(2+)在0.7-8.7 nm范围内。对其他金属络合物进行了测量或计算。附生植物中锌的生物积累似乎受游离锌离子浓度的控制，证实了FIAM。相反，铜的生物积累受弱络合铜(包括Cu2++无机络合物和弱有机络合物)的控制，这与FIAM不一致，似乎是由于自然环境中存在很低的游离Cu2+而限制了铜的扩散。
The free ion activity model (FIAM) has already been confirmed under laboratory conditions for many trace metals but has still to be validated under natural conditions where the presence of natural organic ligands influences metal speciation and bioavailability. The goal of this study was to test if the FIAM is followed under natural conditions by measuring copper and zinc speciation as well as metal accumulation in periphyton. Periphyton was exposed in microcosms to natural river water with different added concentrations of copper (25-258 nM) or zinc (18-501 nM) and additions of a synthetic ligand (NTA). Free Cu2+ was in the range of 10(-16.5)-10(-14.5) M and Zn(2+) was in the range of 0.7-8.7 nM, as measured by competitive ligand exchange coupled with cathodic/anodic stripping voltammetry. Other metal complexes were either measured or computed. Bioaccumulation of zinc in periphyton appeared to be controlled by the free zinc ion concentration, confirming the FIAM. In contrast, bioaccumulation of copper was controlled by weakly complexed copper (including Cu2+ plus inorganic and weak organic complexes), which is in disagreement with the FIAM, and appears to be caused by limitation of copper diffusion due to very low free Cu2+ occurring in natural environments.