Study of the remediation effects of passivation materials on Pb-contaminated soil

The passivation effects of blast furnace slag, fly ash, corncob biochar, and phosphate fertilizer in Pb-contaminated soil was evaluated against the soil pH, available Pb content, Pb fractions, and bioactivity coefficient. Blast furnace slag and fly ash could increase soil pH, while corncob biochar and phosphate fertilizers lowered soil pH. The available Pb content in the blast furnace slag and phosphate fertilizer treatment groups was significantly lower than in other treatments. Also, blast furnace slag and phosphate fertilizer could significantly convert nonresidual Pb into residual Pb. Combined with the environmental impact after application and cost of the material, it is recommended that blast furnace slag can be used as a passivation agent for low-concentration Pb-contaminated soil.