Vertical migration behavior simulation and prediction of Pb and Cd in co-contaminated soil around Pb-Zn smelting slag site

• Published in: Journal of hazardous materials 2024-05, Vol.469, p.133990-133990, Article 133990
• Main Authors: Luo, Ying, Wang, Zhe, Zhang, Yong-De, Zhang, Jia-Qian, Zeng, Qiu-ping, Zhang, Zhen-Long, Tian, Duan, Li, Chao, Peng, Chao-liang, Ye, Kai, Chen, Yi-Ming, Huang, Feng-Yu, Wang, Yu-Ping, Ma, Xiao-ya, Chen, Li
• Format: Article
• Language: English
• Subjects: Anticipate; Convective dispersion equation; Heavy metals; Migrate; PHREEQC
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2024.133990

Heavy metal migration in soil poses a serious threat to the soil and groundwater. Understanding the migration pattern of heavy metals (HMs) under different factors could provide a more reasonable position for pollution evaluation and targetoriented treatment of soil heavy metal. In this study, the migration behavior of Pb and Cd in co-contaminated soil under different pH and ionic strength (NaCl concentration) was simulated using convective dispersion equation (CDE). We predicted the migration trends of Pb and Cd in soils after 5, 10, and 20 years via PHREEQC. The results showed that the migration time of Cd in the soil column experiment was about 60 days faster than that of Pb, and the migration trend was much steeper. The CDE was proved to describe the migration behavior of Pb and Cd (R2 > 0.75) in soil. The predicted results showed that Cd migrated to 15–20 cm of soil within 7 years and Pb stayed mainly in the top 0–6 cm of soil within 5 years as the duration of irrigation increased. Overall, our study is expected to provide new insight into the migration of heavy metal in soil ecosystems and guidance for reducing risk of heavy metal in the environment. [Display omitted] •The CDE model could be applied to actual composite contaminated soils via experiments and multi-parameter simulation.•Cd was a greater threat to groundwater and deep soil than Pb in co-contaminated soils.•The CDE model revealed the spatial evolution of pollutants at regional scale and could be extended at a large scale region.•The amount of soil contamination remediation materials could be quantified via the contamination cube of HMs.