Lee Dae-Young, Fortin Claude, Campbell Peter G C
INRS-Eau, Terre et Environnement, Université du Québec, Institut National de la Recherche Scientifique, 490 de la Couronne, Quebec City, Que., Canada G1K 9A9.
Aquat Toxicol. 2005 Oct 15;75(2):127-35. doi: 10.1016/j.aquatox.2005.06.011.
Short-term silver toxicity was determined for two freshwater algae, Pseudokirchneriella subcapitata and Chlamydomonas reinhardtii, in the presence and absence of chloride. Silver speciation in the exposure media was controlled and algal growth was measured over 6 h. For P. subcapitata, an alga with low Ag uptake fluxes, silver toxicity could be predicted on the basis of the free Ag+ concentration, in the presence or absence of significant complexation by chloride ions, as predicted by the biotic ligand model (BLM). For C. reinhardtii, an alga with high Ag uptake fluxes, silver toxicity was better predicted by the concentration of all labile dissolved Ag species than by free silver, a result that is consistent with diffusion through the unstirred layer surrounding the cell surface being the rate-limiting step in silver uptake. For both species, growth inhibition could be predicted on the basis of the Ag intracellular quota in the presence or absence of chloride, indicating that silver toxicity is a direct result of intracellular accumulation rather than cell surface interactions.
在有氯离子和无氯离子存在的情况下，测定了两种淡水藻类——羊角月牙藻（Pseudokirchneriella subcapitata）和莱茵衣藻（Chlamydomonas reinhardtii）的短期银毒性。控制暴露介质中的银形态，并在6小时内测量藻类生长情况。对于银吸收通量较低的羊角月牙藻，正如生物配体模型（BLM）所预测的那样，无论是否存在氯离子的显著络合作用，银毒性都可以根据游离Ag⁺浓度来预测。对于银吸收通量较高的莱茵衣藻，所有不稳定溶解态银物种的浓度比游离银能更好地预测银毒性，这一结果与通过细胞表面周围未搅拌层的扩散是银吸收的限速步骤一致。对于这两个物种，无论有无氯离子，都可以根据细胞内银配额来预测生长抑制，这表明银毒性是细胞内积累的直接结果，而非细胞表面相互作用的结果。
