Remediation of arsenic and polycyclic aromatic hydrocarbon contaminated soils using electro-microbial combined remediation: effects of soil physicochemical properties

Composite pollution poses a significant challenge for soil remediation. This study simulated arsenic and PAH-contaminated soil in karst regions to evaluate the effectiveness of electro-bioremediation under varying soil conditions. Results showed that Alcaligenes faecalis subsp. faecalis exhibited strong PAH degradation and moderate As(V) reduction capabilities. PAH removal efficiency was maximized (55.93%), while arsenic removal efficiency declined as pH increased. Higher soil organic carbon and available nitrogen reduced arsenic removal, whereas increased available phosphorus enhanced it. Under optimized conditions (35 g/kg organic carbon, 150 mg/kg nitrogen, 50 mg/kg phosphorus), residual arsenic was minimized (118.80 mg/kg), and PAH removal peaked at 45.47%. These findings underscore the pivotal role of soil parameters in remediation efficiency, offering practical insights for optimizing electro-bioremediation strategies for soil contaminated by arsenic and PAH.