Pollution Levels and Associated Health Risks of Heavy Metals in Agricultural Soils in Zhenjiang and Yangzhou, China

This study investigates heavy metal pollution in agricultural soils and its associated health risks in Zhenjiang and Yangzhou in the core of the Yangtze River Delta, China, based on high-density sampling at 449 sites. Although the total concentrations of As and Cd remain below national Risk Intervention Values (GB 15618-2018), the Cd level significantly exceeds the national background, and the potential ecological risk index (PERI) indicates very high ecological risk (>320) at 88.2% of sites, driven primarily by Hg and Cd. The results show acceptable non-carcinogenic risks (HI < 1) for adults and children, but carcinogenic risks are elevated: arsenic alone exceeds the 1 × 10−6 threshold in 71.7% of adult and 92.1% of child scenarios, with the total carcinogenic risk averaging 1.89 × 10−6 (adults) and 3.05 × 10−6 (children). These probabilistic findings justify stricter local action thresholds for As and Cd in this densely populated rice-producing region and demonstrate the value of Monte Carlo simulation for delivering transparent, population-specific risk exceedance probabilities to support evidence-based regional soil management and food-safety policies.