EDF, R&D Division, Département Laboratoire National d'Hydraulique et Environnement, 6 Quai Watier, Chatou, France.
Chemosphere. 2011 Nov;85(9):1496-504. doi: 10.1016/j.chemosphere.2011.08.045. Epub 2011 Oct 10.
The diffusive gradients technique in thin films (DGT) was used to investigate the kinetic resupply of Cd and Cu to pore water from the solid phase. For the sake of simplification, experiments were performed using formulated sediments that differed in the presence or absence of humic acids (HA) and/or of iron hydroxides (i.e., goethite and ferrihydrite). The effects of the time after the contamination of the solid phase (aging effect) on formulated sediments that were coated with goethite and HA and spiked with Cd were also evaluated. Kinetic DGT results were interpreted using the newly developed, multi-compartmental model DGT-PROFS. Due to Cu humate formation, the addition of HA slightly increased the Cu concentration in the pore water independent of the effect of the iron hydroxide coating on the formulated sediments and slightly decreased that of Cd. The impact of 8-190d of aging resulted in a significant decrease in the Cd concentration of the pore water over an increasing incubation time. Modeling our results with DGT-PROFS led to the following conclusions concerning the impact of HA and iron hydroxides on Cd and Cu availability. First, in the presence of HA and absence of iron hydroxides, Cd is associated mainly with weak sites, while Cu is bound to strong sites. Similarly, in the presence of both iron hydroxides and HA, Cu appeared to be more heavily associated with the strong sites than did Cd. When the incubation time increased from 8 to 190d, a proportion of Cd initially adsorbed onto weak sites transferred to the strong sites, suggesting that the adsorption of Cd on sediments is controlled partially by slow kinetic processes.
薄膜中的扩散梯度技术（DGT）用于研究从固相到孔隙水中 Cd 和 Cu 的动力学补给。为了简化实验，使用了含有或不含有腐殖酸（HA）和/或铁氢氧化物（即针铁矿和水铁矿）的配方沉积物进行实验。还评估了固相污染后时间（老化效应）对涂覆有针铁矿和 HA 并添加 Cd 的配方沉积物的影响。使用新开发的多隔室模型 DGT-PROFS 对动力学 DGT 结果进行了解释。由于 Cu 腐殖酸盐的形成，添加 HA 会略微增加孔隙水中的 Cu 浓度，而与铁氢氧化物涂层对配方沉积物的影响无关，并略微降低 Cd 的浓度。8-190d 的老化影响导致孔隙水中 Cd 浓度随着孵育时间的增加而显著降低。使用 DGT-PROFS 对我们的结果进行建模，得出了以下关于 HA 和铁氢氧化物对 Cd 和 Cu 有效性的影响的结论。首先，在存在 HA 且不存在铁氢氧化物的情况下，Cd 主要与弱结合位点结合，而 Cu 与强结合位点结合。同样，在同时存在铁氢氧化物和 HA 的情况下，Cu 似乎比 Cd 更强烈地与强结合位点结合。当孵育时间从 8 天增加到 190 天时，最初吸附在弱结合位点上的一部分 Cd 转移到强结合位点，表明 Cd 在沉积物上的吸附部分受慢速动力学过程的控制。
