Eawag, Swiss Federal Institute of Aquatic Science and Technology, P.O. Box 611, CH-8600 Duebendorf, Switzerland.
Environ Pollut. 2010 Mar;158(3):641-8. doi: 10.1016/j.envpol.2009.10.031. Epub 2009 Nov 12.
Accumulation of cadmium in periphyton was investigated under field conditions while Cd concentration and speciation were dynamically varying in a small stream during rain events. Speciation in water was determined in situ by diffusion gradient in thin-films (DGT) and by modeling of complexation with fulvic acids. During the rain events, dissolved Cd concentrations increased from 0.17 nM to 0.27-0.36 nM, and 70-97% were DGT-labile. Cd content in periphyton closely followed Cd concentrations in water, despite higher concentrations of Zn and Mn, and may be controlled by either free or DGT-labile Cd concentrations. Decrease of Cd content in periphyton after the rain events was slower than the decrease of Cd concentration in water. Concentrations of Zn, Mn, Cu, Pb and Fe in periphyton also followed the dynamic variations of metal concentrations in water. Repeated exposure of periphyton to elevated dissolved Cd may lead to Cd accumulation.
在野外条件下研究了在降雨事件中小溪中 Cd 浓度和形态不断变化时底栖藻类中镉的积累情况。通过扩散梯度薄膜（DGT）原位测定水中的形态，并通过与腐殖酸络合的建模来确定形态。在降雨事件期间，溶解态 Cd 浓度从 0.17 nM 增加到 0.27-0.36 nM，其中 70-97%是 DGT 不稳定的。尽管 Zn 和 Mn 的浓度较高，但底栖藻类中的 Cd 含量仍与水中的 Cd 浓度密切相关，这可能受游离态或 DGT 不稳定态 Cd 浓度的控制。降雨事件后底栖藻类中 Cd 含量的下降速度比水中 Cd 浓度的下降速度慢。底栖藻类中 Zn、Mn、Cu、Pb 和 Fe 的浓度也随水中金属浓度的动态变化而变化。底栖藻类反复暴露于升高的溶解态 Cd 中可能会导致 Cd 积累。
