Meylan Sébastien, Behra Renata, Sigg Laura
Swiss Federal Institute of Environmental Science and Technology (EAWAG), P.O. Box 611, CH-8600 Dübendorf, Switzerland.
Environ Sci Technol. 2003 Nov 15;37(22):5204-12. doi: 10.1021/es034566+.
Although the free ion activity model (FIAM) has been well-established in laboratory studies, there remains the need for field data in order to validate the applicability of this model in natural systems. The objective of this study was to investigate the response of copper and zinc accumulation in periphyton to short-term variations in metal concentration and speciation in freshwater. During heavy rain events, dissolved Cu in the Furtbach stream increased from 40 to 118 nM, while dissolved Zn increased from 45 to 147 nM due to the release of metals from contaminated sediments. Increases in free copper and free zinc ions in the water (from 10(-14) to 10(-11.5) M for Cu2+; from 1 to 15 nM for Zn2+) were observed during the onset of heavy rain events. Periphytic algae collected from artificial substrates had an intracellular copper content (0.2-2.8 micromol/g dry weight (dw)) that varied as a function of the exchangeable copper in the water (labile form) rather than the free Cu2+. Intracellular zinc content (1.5-8.0 micromol/g dw) was found to follow the same trend as the free zinc ion concentration. Adsorbed Cu and Zn on periphyton showed a very dynamic response to variations in dissolved metal concentration. Different concentrations of dissolved manganese during the two time periods may affect the accumulation of zinc and copper by competition for metal uptake.
尽管自由离子活性模型（FIAM）在实验室研究中已得到充分确立，但仍需要实地数据来验证该模型在自然系统中的适用性。本研究的目的是调查淡水周丛生物中铜和锌积累对金属浓度和形态短期变化的响应。在暴雨期间，富特巴赫溪中的溶解铜从40 nM增加到118 nM，而溶解锌从45 nM增加到147 nM，这是由于受污染沉积物中金属的释放所致。在暴雨开始时，观察到水中的游离铜离子和游离锌离子增加（Cu2+从10^(-14) M增加到10^(-11.5) M；Zn2+从1 nM增加到15 nM）。从人工基质收集的周丛藻类细胞内铜含量（0.2 - 2.8微摩尔/克干重）随水中可交换铜（不稳定形态）而非游离Cu2+的变化而变化。细胞内锌含量（1.5 - 8.0微摩尔/克干重）与游离锌离子浓度呈现相同趋势。周丛生物上吸附的铜和锌对溶解金属浓度的变化表现出非常动态的响应。两个时间段内不同浓度的溶解锰可能通过竞争金属吸收来影响锌和铜的积累。
