Probabilistic assessment of cumulative heavy metal exposure from staple foods in a selenium-endemic area: Implications for dietary risk management

While selenium (Se) exposure in endemic poisoning areas has been extensively investigated, its co-occurrence with other heavy metals and the implications for integrated environmental health management remain insufficiently addressed. This study developed a risk-based dietary optimization framework by assessing the concentrations, spatial distribution, and probabilistic health risks of 24 elements in four staple crops (rice, maize, potato, and sweet potato) collected from Shuang’an Township, a recognized human Se poisoning area in China. Results revealed widespread exceedances of maximum limits (ML) for Cd, Se, Cr, Zn, and Cu, with Cd (65.8% of samples exceeded ML; maximum exceedance factor = 145.7) and Se (52.1% exceeded ML; maximum exceedance factor = 56.3) posing the most significant risks. Potatoes exhibited the highest contamination levels among all crops. Monte Carlo simulations demonstrated that dietary composition substantially influenced cumulative health risks, with total target hazard quotient (TTHQ) values ranging from 9 to 24 under different consumption scenarios. Potato intake showed a significant positive correlation with TTHQ (r = 0.67, p < 0.05), whereas sweet potato intake showed a significant negative correlation (r = –0.71, p < 0.05), indicating sweet potato as a comparatively lower-risk alternative. The proposed probabilistic framework provides useful information for dietary risk management in Se-endemic areas. These findings highlight the necessity of shifting from a Se-centered management perspective toward integrated multi-metal risk control strategies in Se-endemic areas.