Phytoremediation of Mixed Contaminated Soils: Enhancement with Biochar and Compost Amendments

Abstract

Pot experiments were conducted to study the effects of biochar and compost amendment on phytoremediation of mixed contaminated soil using sunflower plant, oat plant and rye grass. Mixed contaminated soil was prepared by mixing the soil with 50 mg/kg naphthalene, 100 mg/kg phenanthrene, 500 mg/kg Pb, 50 mg/kg Cd, and 200 mg/kg Cr. One set of experiments with the soil amended with 50 g/kg biochar and another set of experiments with soil amended with 200 g/kg compost were conducted. The amended soils were filled in pots and plants were grown in them for 61 days. Plants grown in uncontaminated-unamended soil and contaminated-unamended soil were taken as controls. The change in growth characteristics of oat plant and rye grass by amendments was not significant. Sunflower had better germination and growth characteristics in amended soil compared to unamended soil. The germination and growth characteristic and biomass of the plants were better in compost-amended soil compared to biochar-amended soils in sunflower plants. Cd and Pb removal from the soil was better for all the plants in the presence of amendments, but Cr removal was unaffected by addition of amendments. In planted soils, PAH concentrations were reduced by the presence of amendments. The results suggest that biochar and compost amendments can improve the plant growth characteristics and enhance phytoremediation of mixed contaminated soils.