The particle-size sieving technique to remediate Pb- and Cu-contaminated agricultural soil

In order to find a cost-effective remediation to treat lead (Pb)- and copper (Cu)-contaminated agricultural soil, the particle-size sieving technique (PST) combined with the replacement of clean sands was employed in this study. The speciation and removal efficiency of lead and copper in the contaminated soil were investigated. The sieving separation was carried out by dry sieving (screening sizes ranging from 4.000 to 0.025 mm) and wet sieving (three different sizes of 2.000–0.053, 0.053–0.002 and <0.002 mm). The results indicate that the organic and exchangeable species concentration of heavy metals in the contaminated soil is proportional to the organic matter and water content of the soil. The concentration of heavy metals is unrelated to particle sizes greater than 0.053 mm soil under the dry-sieving PST. For soil particles of size 2.000–0.053 mm, the heavy-metal concentration of soil treated by the dry-sieving PST is higher than that of the wet-sieving PST because the dry-sieving PST cannot separate finer soil particles (<0.053 mm) completely. Both dry- and wet-sieving PSTs with replacement of clean sands can decrease the heavy-metal concentration of the contaminated soil dramatically, and the remediated soil has the potential to be restored to its cultivation function.