Multi-indicator assessment and probabilistic human health risks of heavy metals in rice and soils system in Eastern China

Contamination of agricultural soils by heavy metals presents a serious risk to food safety and public health, particularly in intensive farming regions of China. This study comprehensively evaluated heavy metal concentrations in soils and rice grains from major agricultural areas of Anhui province. Results revealed that cadmium (Cd) and mercury (Hg) were the predominant pollutants in both soil and rice grain samples, with geo-accumulation index (Igeo) and potential ecological risk index (RI) values indicating moderate to considerable contamination and ecological risk. Source apportionment, performed using positive matrix factorization (PMF) and principal component analysis (PCA), attributed the majority of heavy metal inputs to anthropogenic activities, particularly industrial emissions and intensive agricultural practices. Health risk assessment employing Monte Carlo simulation indicated that carcinogenic and non-carcinogenic risks for adults were generally within acceptable thresholds. However, children exhibited elevated vulnerability, with probabilities of 0.23% and 7.29% for exceeding non-carcinogenic and carcinogenic risk thresholds, respectively. These findings provide critical insights for developing targeted remediation strategies to mitigate heavy metal contamination in agricultural soils and safeguard food safety.