Department of Ecological Science, Faculty of Earth and Life Sciences, VU University, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands.
Environ Pollut. 2013 Sep;180:122-30. doi: 10.1016/j.envpol.2013.05.024. Epub 2013 Jun 5.
The aim of this study was to improve our understanding of metal bioavailability in soil by linking the biotic ligand approach with toxicokinetics modelling. We determined cadmium bioaccumulation kinetics in Folsomia candida (Collembola) as a function of soil pH. Animals were exposed for 21 days to LUFA 2.2 soil at 5 or 20 μg Cd g(-1) dry soil followed by 21 days elimination in clean soil. Internal cadmium concentrations were modelled using a first-order one-compartment model, relating uptake rate constants (k1) to total soil, water or 0.01 M CaCl2 extractable and porewater concentrations. Based on total soil concentrations, k1 was independent of soil pH while it strongly increased with increasing pH based on porewater concentrations explaining the reduced competition of H(+) ions making cadmium more bioavailable in pore water at high pH. This shows that the principles of biotic ligand modelling are applicable to predict cadmium accumulation kinetics in soil-living invertebrates.
本研究旨在通过将生物配体方法与毒代动力学模型相结合，提高我们对土壤中金属生物可利用性的理解。我们测定了 Folsomia candida（弹尾目）体内镉的生物积累动力学，作为土壤 pH 的函数。动物在 5 或 20μg Cd g（-1）干土的 LUFA 2.2 土壤中暴露 21 天，然后在清洁土壤中消除 21 天。使用一阶单室模型对内部镉浓度进行建模，将摄取率常数（k1）与总土壤、水或 0.01 M CaCl2 可提取和孔隙水浓度相关联。基于总土壤浓度，k1与土壤 pH 无关，而基于孔隙水浓度则强烈增加，这解释了 H（+）离子竞争的减少，使镉在高 pH 值时在孔隙水中更具生物利用性。这表明生物配体模型的原理适用于预测土壤中生活的无脊椎动物体内镉的积累动力学。
