Ecological and human health hazards of soil heavy metals after wildfire: A case study of Liangshan Yi autonomous prefecture, China

Soilsamples were collected in at different depths from the conflagration area inLiangshan Yi Autonomous Region, China, to investigate the distributioncharacteristics and ecological and human health risks of heavy metals after awildfire. The samples collected comprise wildfire ash (WA) above the soilsurface, ash soil (AS) 0–5 cm, and plain soil (PS) 5–15 cm below the soilsurface. Additionally, reference soil (RS) was collected from a nearby unburnedarea at the same latitude as the conflagration area. The results showed thatthe concentrations of zinc (Zn), copper (Cu), lead (Pb), and cadmium (Cd) inthe WA and AS were significantly higher than in reference soil (RS) (p <0.05). Concentrations of Pb in the PS were 2.52 times higher than that in RS(17.9 mg kg⁻¹) (p < 0.05). The AS and WA had the highest Index ofpotential ecological risks (RI > 600). In addition, The Cd in AS and WAcontributed the most to the highest Improved nemerow index (INI) and RI with acontribution of more than 80%. The concentration of heavy metals was used toestablish non-carcinogenic effects and cancer risks in humans via threeexposure pathways: accident ingestion of soil, dermal contact with soil, andinhalation of soil particles. Hazard index (HI) values of each sample were allless than 1, indicating the non-carcinogenic risk was within the acceptablerange and would not adversely affect the local population's health. The Cancerrisk (CR) values of Cr, As, Cd, and Ni were all below 1 × 10⁻⁶,indicating that heavy metal pollution from this wildfire did not pose a cancerrisk to residents. Copyright © 2024 Elsevier Ltd. All rights reserved.