Combined effects of earthworms and biochar on PAHs-contaminated soil remediation: A review

Abstract

• Earthworm remove PAHs from soil by bioaccumulation and stimulating microbial degradation. • Biochar can adsorb PAHs and promote microbial degradation in soil. • Earthworm improve the adsorption process of biochar by bioturbation. • Biochar reduce the vermiaccumulation and improve the decomposition of PAHs by earthworm. Polycyclic aromatic hydrocarbons (PAHs) in soil pose a threat to the health of humans and other organisms due to their persistence. The remediation method of combined application of biochar and earthworms has received growing attention owing to its effectiveness in PAHs removal. However, the earthworm-biochar interaction and its influence on PAHs in soil has not been systematically reviewed. This review focuses on the effectiveness of combined application of earthworms and biochar in the remediation of PAHs-contaminated soils and the underlying mechanisms, including adsorption, bioaccumulation, and biodegradation. Earthworm-biochar interaction activates the functional microorganisms in soil and the PAHs-degrading microorganisms in earthworm guts, promoting PAHs biodegradation. This review provides a theoretical support for the combined application of biochar and earthworms in the remediation of PAHs-contaminated soils, points out the limitations of this remediation method, and finally shows the prospects for future research. [Figure not available: see fulltext.]