Abstract: The remediation of agricultural and mountain soils contaminated by atmospheric deposition of heavy metals has emerged as a new research hotspot, following the remediation of typical industrially polluted sites. Such contaminated areas are usually extensive, involving large volumes of soil with generally lower contamination levels compared to factory zones in industrial areas. To evaluate the applicability and cost-effectiveness of the leaching remediation technology in the treatment of such pollution, the representative atmospheric-heavy metal-polluted agricultural and mountain soils were selected from the vicinity of an industrial area in Zhuzhou city, Hunan province. The particle-size fractionation leaching experiments were conducted, soils were separated into fine (<0.074 mm), medium (0.074-0.250 mm), and coarse (>0.250 mm) fractions. Results showed that fine particles accounted for more than 60% of agricultural soils, and heavy metal concentrations increased with the increase of particle size. The concentration of heavy metals in sandy mountain soils was also related to particle size. Particle-size-specific leaching could reduce polluted agricultural soils by 78%-82% and by more than 31% in mountain soils. These findings provided a technical reference for the large-scale remediation of soils contaminated by atmospheric deposition of heavy metals.

Key words: heavy metals, leaching, agricultural soil, mountain soil, remediation, particle-size, reduction