Lock K, Janssen C R
Laboratory of Environmental Toxicology and Aquatic Ecology, Ghent University, J. Plateaustraat 22, 9000 Gent, Belgium.
Environ Pollut. 2003;126(3):371-4. doi: 10.1016/s0269-7491(03)00232-x.
Currently, soil quality criteria or soil risk assessments of metals are based on laboratory toxicity tests which are carried out in soils freshly spiked with metal salts. With these data, species sensitivity distributions are fitted, from which hazardous concentrations and predicted no effect concentrations are derived. However, due to long-term processes, called ageing, soil metal availability decreases with time. Here we show that pH is the most important parameter determining the effect of ageing on zinc partitioning in soils, with the effect of ageing becoming more important with increasing pH. Furthermore, zinc bioavailability, expressed as the internal zinc concentrations in red clover (Trifolium pratense) is closely related to pore water zinc concentration. In addition, there is a clear dose-response relationship between the survival of the earthworm Eisenia fetida and the calcium chloride-extracted zinc fraction. These results indicate that zinc partitioning can be used to predict zinc bioavailability to terrestrial organisms. However, the use of spiked soils in toxicity assays can result in an over-estimation of the effects of zinc, especially at a high pH.
目前，金属的土壤质量标准或土壤风险评估是基于实验室毒性测试，这些测试在新添加金属盐的土壤中进行。利用这些数据，拟合物种敏感性分布，从中得出有害浓度和预测无效应浓度。然而，由于称为老化的长期过程，土壤中金属的有效性会随时间降低。在这里，我们表明pH是决定老化对土壤中锌分配影响的最重要参数，随着pH的升高，老化的影响变得更加重要。此外，以红三叶草（Trifolium pratense）体内锌浓度表示的锌生物有效性与孔隙水锌浓度密切相关。此外，蚯蚓 Eisenia fetida 的存活率与氯化钙提取的锌组分之间存在明显的剂量反应关系。这些结果表明，锌的分配可用于预测锌对陆地生物的生物有效性。然而，在毒性试验中使用添加土壤可能会导致对锌效应的高估，尤其是在高pH值下。
