Plant and algal toxicity of persistent free radicals and reactive oxygen species generated by heating anthracene-contaminated soils from 100 to 600 °C

Persistent free radicals (PFRs) are emerging contaminants of increasing concern, yet their formation, fate, toxicity and health risk poorly known. Thermal treatment, a common remediation technique to clean industrial soils, induces the formation PFRs, which could paradoxically increase soil toxicity, contrary original objective remediation. Actually, there is little knowledge on PFRs in soils contaminated by polycyclic aromatic hydrocarbons (PAHs). Here we studied generation spiked with anthracene heated 1 h from 100 600 °C, using electron paramagnetic resonance. We also investigated reactive oxygen species (ROS), e.g. superoxide radical (O2·?), hydrogen peroxide (H2O2) hydroxyl (·OH), aqueous phase thermal-treated soil, impact heating oxidative potential, wheat growth green algae activity. Results showed that ROS, plant algal show similar trend an 300 followed decrease °C. Scavenger trapping tests reveal mainly due O2·?, ·OH H2O2 induced anthracene-PFRs have negligible direct toxicity. Overall, our findings unintended toxic compounds peaking at °C during thermal PAH-contaminated soils. These results should help assess environmental thermally treated