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Updated: Mar 24, 2026
Integrated Field Lysimetry and Porewater Sampling for Evaluation of Chemical Mobility in Soils and Established Vegetation
Published on: July 4, 2014
Comparative study of promising CaAl-LDH and conventional immobilizing agents in mitigating ecological and health
Jianying Yu1, Nan Wei2, Haochen Fang3
1The Second Geological Exploration Institute, China Metallurgical Geology Bureau, Fuzhou, 350108, China.
Abstract:
Soil lead (Pb) contamination poses a significant global threat to both ecological safety and human health. While conventional immobilizing agents effectively reduce Pb mobility, they exhibit inherent limitations, necessitating the development of novel remediation materials. Furthermore, the remediation efficacy of these agents remains inadequately characterized, as comprehensive evaluations-particularly those assessing the reduction of human health risks via oral ingestion-are frequently omitted. In this comparative study, three types of immobilizing agents, namely, the conventional KH2PO4 and Ca(OH)2, and the promising CaAl-Layered double hydroxide (LDH), were applied to remediate five typical Pb-contaminated soil types in China: red, cinnamon, black, brown, and yellow soils. The remediation efficacy was comprehensively evaluated in terms of the migration factor, ecological risk, and human health risk of soil Pb. The results indicated that at their respective optimal application rates, KH2PO4, Ca(OH)2, and CaAl-LDH significantly reduced the migration factor of soil Pb by averages of 66.7%, 16.1%, and 56.0%, respectively. Furthermore, the leachability and relevant ecological risk associated with soil Pb were reduced by 93.2%, 93.7%, and 56.3%, respectively. Notably, CaAl-LDH exhibited superior performance in mitigating Pb bioaccessibility and relevant human health risk, with average reductions of 42.1% and 48.6% in the gastric and small intestinal phases, respectively. The reduction efficacy of CaAl-LDH in the gastric and small intestinal phases was 4.21 and 3.90 times and 2.17 and 1.17 times that of KH2PO4 and Ca(OH)2, respectively. These results demonstrate the effectiveness of CaAl-LDH for Pb immobilization and its potential for field-scale application. This study provides a scientific foundation for the research and development of highly efficient immobilization agents for Pb-contaminated soils and the improvement of eco-environmental quality and human health.
