TRIAD method to assess ecological risks of contaminated soils in abandoned mine sites

Site-specific soil ecological risk assessment is important for protecting soil ecosystems because it reflects the environmental factors at the site to detect ecological risks and develop risk management measures. This study assessed the ecological risks from chemical pollutants in abandoned mine sites using the TRIAD approach, evaluating its overall applicability, including the tiered system of assessment. A site-specific soil ecological risk assessment was conducted for five abandoned mine sites (Sites 1–4 and R, the reference site); integrated risks (IRs) for each site were calculated. Our results of the Tier 2 assessment showed that IRs at Sites 1–4 were 0.701, 0.758, 0.840, and 0.429, respectively. The IR classification was moderate, high, high, and low risk, in that order for Sites 1–4, the same as that for Tier 1. The IR had more varied analyses, emphasizing the significance of conducting higher tiered analyses under TRIAD while maintaining a balance between soil ecosystem protection and socioeconomic costs. Multiple analyses reduced the uncertainty of IR, thus enabling efficient risk management decision-making to protect soil ecosystems. Our study provides a basis for using the TRIAD for soil assessment and establishing policies for site-specific soil ecological risk assessments.