Ecological responses and reduced estimated dietary cancer risk in PAH-contaminated soil following dual-oxidant remediation

Although conventional single-oxidant remediation can effectively degrade polycyclic aromatic hydrocarbons (PAHs), these approaches may destabilize soil properties and disrupt microbial community functions, potentially compromising ecosystem stability and agricultural productivity. This study optimized and evaluated a dual-oxidant system of sodium persulfate (PS)/calcium peroxide (CP) from a food-chain perspective, focusing on PAH accumulation in vegetables and associated human health risks. The optimized system removed 76.21% of ΣPAHs, with degradation rates exceeding 90% for high-molecular-weight PAHs (HMW-PAHs), attributed to the synergistic generation of SO·- 4 and ·OH. Notably, CP addition can improve soil environmental conditions and reduce the impacts of remediation on soil bacterial community structure. Meanwhile, PAH accumulation in vegetables decreased by 53.5-78.9%, lowering lifetime cancer risk by up to 72.3%. These results demonstrate that dual-oxidant remediation effectively controls pollutant migration from soil to crops, highlighting its potential to reduce dietary exposure and improve food safety in contaminated agricultural systems.