[Meta Analysis of Stabilization Effect of Phosphorus on Soil Lead and Its Influencing Factors]

Phosphorus exerts a good stabilization effect on soil lead. In this study, the findings of 90 papers were summarized using the Meta-analysis method. These papers described the immobilization of soil lead using phosphorus from 1997 to 2022. The effects of phosphorus materials on the stabilization rate and speciation transformation of soil Pb and soil pH were quantitatively analyzed based on soil properties, stabilization process conditions, and types of phosphorus materials. The results revealed that the stronger the soil alkalinity (pH ≥ 7.5), the lower is the content of lead (≤ 500 mg·kg^-1), and the higher the content of soil organic matter (>0.5%), the more conducive it is to the phosphorus-based stabilization of soil lead; the stabilization rates are 75.21%, 34.97% and 93.12%, respectively. In terms of stabilization process conditions, the higher the addition amount of phosphorus (≥ 10%), the higher is the water content (>50%)and longer is the curing time (≥ 30 days), and the higher the curing temperature (≥ 40℃), the more conducive it is to the stabilization of soil lead, and the stabilization rates are 80.65%, 84.98%, 79.39%, and 41.44%, respectively. According to the types of phosphorus, soluble phosphorus had a high stabilization rate of soil lead (96.24%). The conversion rate of exchangeable lead and carbonate-bound lead to residual lead was 95.93%. Soluble phosphorus was majorly acidic, reducing the soil pH by 7.27%, whereas insoluble phosphorus was majorly alkaline, increasing the soil pH by 3.63%. In conclusion, when the soil pH ≥ 7.5, soil lead content ≤ 500 mg·kg^-1, soil organic matter content >0.5%, soluble phosphorus addition ≥ 10%, water content >50%, curing time ≥ 30 days, and curing temperature ≥ 40℃, phosphorus had a better effect on soil Pb stabilization. In the actual remediation process of lead-contaminated soil, to improve the lead stabilization rate, it is necessary to comprehensively consider the effects of soil properties, stabilization process conditions, phosphorus, and other factors.