Feasibility study of PAHs contaminated soil remediation by Buchloe dactyloides (Nutt.) Engelm combined with biochar

Although the combined plant-biochar remediation in improving soil contaminated by polycyclic aromatic hydrocarbons (PAHs) is considered efficient (Singha and Pandey in Crit Rev Biotechnol 41:749–766, 2021), the potential for application remains poorly known. This study used clones of Buchloe dactyloides to evaluate the effects of biochar on the capability of phytoremediation and rhizosphere soil contaminated with PAH.

Pot experiments were conducted to assess the effects of biochar on growth physiological parameters of B. dactyloides growth, accumulation of PAHs in B. dactyloides, and soil environment.

The results showed that the application of biochar increased the levels of antioxidants (free proline, glutathione, and ascorbic acid), antioxidant enzymes (catalase and laccase), and phytohormones (abscisic acid, indole acetic acid, jasmonic acid, salicylic acid, and gibberellin), decreased the accumulation of reactive oxygen species and lipid peroxidation in the roots, thereby enhancing the antioxidant defense ability and improving PAHs tolerance in roots of B. dactyloides. Moreover, the activities of enzymes (catalase, dehydrogenases, urease and protease) and soil nutrients in the rhizosphere soil were significantly increased, the content of PAHs decreased, and the health of the rhizosphere soil was improved.

Biochar treatment promoted the accumulation of PAHs, improved soil environment and significantly enhanced the effects of phytoremediation. Therefore, the combined application of B. dactyloides and biochar can be considered as a feasible approach for the phytoremediation of PAH-contaminated soil.