Ministry of Education (MOE) Key Laboratory of Environmental Remediation and Ecosystem Health, College of Environmental and Resources Science, Zhejiang University, Hangzhou, 310058, People's Republic of China.
PEIE Research Chair for the Development of Industrial Estates and Free Zones, Center for Environmental Studies and Research, Sultan Qaboos University, Al-Khoud 123, Muscat, Oman.
Chemosphere. 2020 Dec;261:127763. doi: 10.1016/j.chemosphere.2020.127763. Epub 2020 Jul 23.
As arable land has become an important sink for cadmium (Cd), soil is being recognized as a major source of metals to the food chain. It becomes, therefore, essential to investigate metal mobility in contaminated soils and to identify suitable remediation strategies. For this, immobilization of Cd was evaluated in contaminated stagnic anthrosol: S1, gleysol: S2 and fluvisol: S3 under flow through conditions. Ten treatments including control were tested alone or in composite form firstly at natural Cd contents (0.58-0.69 mg kg). Here, T2 (lime), T5 (biochar) and T10 (composite amendment) were found better in reducing the Cd concentration in the soils' leachates, so, their efficacy was further investigated in the same soils of higher Cd contents (1 and 2 mg kg imposed by soil spiking). Amendments significantly reduced the leachate metal contents especially in 1 mg kg spiked soils. Characterization of T2, T5 and T10 revealed their structural transformations in all the studied soil types, while active functional groups e.g. C-O, CO, O-H, Si-O-Si, ester and alcoholic groups were notably involved in Cd precipitation or adsorption on amendments surface. Variations in Cd speciation in these soils exhibited the exchange of Cd to more stable fractions with tested amendments. These continuous-flow experiments confirmed the strong efficiency of T2, T5 and T10 in reducing the Cd concentration in the leachate of three soils. This study has strong implications in understanding the role of different amendments in controlling the fate, leaching behavior and immobilization of Cd in diverse soil types.
由于耕地已成为镉（Cd）的重要汇，因此土壤被认为是金属向食物链迁移的主要来源。因此，有必要研究污染土壤中金属的迁移性，并确定合适的修复策略。为此，在流动条件下评估了受污染的停滞性人为土（S1）、潜育土（S2）和冲积土（S3）中 Cd 的固定化。首先在天然 Cd 含量（0.58-0.69 mg kg）下测试了包括对照在内的 10 种单独或复合处理。在此，T2（石灰）、T5（生物炭）和 T10（复合改良剂）在降低土壤浸出液中 Cd 浓度方面表现更好，因此在 Cd 含量更高的相同土壤（通过土壤加标达到 1 和 2 mg kg）中进一步研究了它们的功效。改良剂显著降低了浸出液中金属含量，尤其是在加标 1 mg kg 的土壤中。对 T2、T5 和 T10 的特性研究表明，它们在所有研究的土壤类型中都发生了结构转化，而活性官能团，如 C-O、CO、O-H、Si-O-Si、酯和醇基，明显参与了 Cd 的沉淀或吸附在改良剂表面。这些土壤中 Cd 形态的变化表明，Cd 与测试的改良剂交换到更稳定的组分。这些连续流动实验证实了 T2、T5 和 T10 在降低三种土壤浸出液中 Cd 浓度方面的强大效率。这项研究对于理解不同改良剂在控制不同土壤类型中 Cd 的命运、淋滤行为和固定化方面的作用具有重要意义。
