Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Guangdong Institute of Eco-environmental Science & Technology, Guangzhou 510650, PR China.
Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Guangdong Institute of Eco-environmental Science & Technology, Guangzhou 510650, PR China.
Sci Total Environ. 2019 Feb 10;650(Pt 1):313-320. doi: 10.1016/j.scitotenv.2018.08.327. Epub 2018 Aug 25.
Soil particles exert a significant influence on the migration of heavy metals in soil and water environments. In this study, a simulated rainfall experiment was conducted to investigate the loss characteristics of cadmium (Cd) from a red soil surface. Two rainfall intensities (50 and 100 mm h) were considered and the distribution of Cd in different fractions (>1, 1-0.25, 0.25-0.05 and <0.05 mm) of aggregates lost from the soil was examined. The result showed that in the artificially polluted soil, the Cd content in different aggregates decreased with particle size, with the lowest Cd content in the <0.05 mm fraction aggregates. In the rainfall experiment, the runoff rate generally increased with the rainfall duration, while the sediment yield rate first increased and then remained stable. The loss rates of various fractions of aggregates in the sediment generally followed the order of (<0.05) mm > 1-0.25 mm > 0.25-0.05 mm > (>1) mm. The proportions of the <0.05 mm-fraction aggregates were the highest in the loss sediment throughout the entire rainfall process. The lost Cd was transported mainly in the sediment-bound form, while only a very small portion of Cd was lost in the water phase of runoff. High rainfall intensity led to greater Cd loss in runoff. In the lost sediment, the concentration of Cd was higher in the macroaggregates. The phenomenon of Cd enrichment in the fine particles was not observed. Although the concentration of Cd in the <0.05 mm fraction was the lowest, the contribution of this fraction to the total Cd content in the sediments was the highest.
土壤颗粒对重金属在土壤和水环境中的迁移有重要影响。本研究通过模拟降雨实验，研究了镉（Cd）从红壤表面的流失特征。考虑了两种降雨强度（50 和 100mm/h），并考察了Cd 在从土壤中损失的不同团聚体（>1、1-0.25、0.25-0.05 和<0.05mm）分数中的分布。结果表明，在人为污染土壤中，不同团聚体中的 Cd 含量随粒径减小而降低，<0.05mm 分数的团聚体中 Cd 含量最低。在降雨实验中，径流量通常随降雨持续时间的增加而增加，而泥沙产率先增加后保持稳定。泥沙中各团聚体分数的损失率通常遵循（<0.05）mm>1-0.25mm>0.25-0.05mm>(>1)mm 的顺序。在整个降雨过程中，<0.05mm 分数的团聚体在损失的泥沙中比例最高。流失的 Cd 主要以与泥沙结合的形式输送，而只有很少一部分 Cd 流失在径流水相。高降雨强度导致径流中 Cd 流失量更大。在损失的泥沙中，Cd 在大团聚体中的浓度较高。未观察到 Cd 在细颗粒中富集的现象。尽管<0.05mm 分数中的 Cd 浓度最低，但该分数对泥沙中总 Cd 含量的贡献最高。
