Removal of soil polycyclic aromatic hydrocarbons derived from biomass fly ash by plants and organic amendments

Phytoremediation using maize (Zea mays L.) assisted by the compost or vermicompost amendments was the most appropriate strategy for bioremediation of soil contaminated by polycyclic aromatic hydrocarbons (PAHs) derived from biomass fly ash. Higher removal of low molecular weight PAHs than medium and high molecular weight PAHs within the same treatment were observed. The total PAH content in planted soil with compost or vermicompost was decreased in a range between 62.9-64.9%. There were no significant differences (P < 0.05) between the compost and vermicompost amendments on the total removal of ash-PAHs. The content of PAH derived by ash did not have adverse effect on maize cultivation and biomass yield. The contribution of PAH reduction by maize roots on the soil total PAH removal was negligible. Therefore, maize significantly boosted the PAH removal in soil. The harvested maize shoots did not represent any environmental risk.