Barros H, Abril J M
Department Física Aplicada I, EUITA, Universidad de Sevilla, Carretera de Utrera, Km 1, Sevilla DP 41013, Spain.
Water Res. 2004 Feb;38(3):749-55. doi: 10.1016/j.watres.2003.10.015.
Dispersion of pollutants in aquatic environments depends on their uptake by suspended solids. This work deals with the uptake kinetics of 133Ba (gamma-emitter and a good analogue of 226Ra) by suspended estuarine sediments (which can be resuspended into the water column under certain conditions). This study presents a wide set of tracing experiments, including second tracing, decantation and desorption processes. The purpose is to characterize 133Ba uptake by sediments and to investigate the use and limitations of box models in order to describe the uptake kinetics. Water and sediment samples were collected in the Huelva estuary (Spain), where environmental 226Ra concentrations have been increased by two phosphate fertilizer industries. Samples were characterized by granulometric, organic carbon content, cation exchange capacity and XRF-EP analyses. Results revealed three-step kinetics, with characteristic times of minutes, hours and days. These results enabled the selection and calibration of a suitable box model and facilitated the testing of its use as a fully predictive tool.
污染物在水生环境中的扩散取决于它们被悬浮固体的吸收情况。这项工作研究了河口悬浮沉积物对133Ba（γ射线发射体，是226Ra的良好类似物）的吸收动力学（在特定条件下，这些沉积物可重新悬浮到水柱中）。本研究展示了一系列广泛的示踪实验，包括二次示踪、倾析和脱附过程。目的是表征沉积物对133Ba的吸收情况，并研究箱式模型在描述吸收动力学方面的应用及局限性。在韦尔瓦河口（西班牙）采集了水和沉积物样本，那里两家磷肥厂使环境中226Ra的浓度有所增加。通过粒度分析、有机碳含量、阳离子交换容量和X射线荧光能谱分析对样本进行了表征。结果显示出三步动力学，其特征时间分别为分钟、小时和天。这些结果有助于选择和校准合适的箱式模型，并便于测试其作为完全预测工具的用途。
