Optimizing dietary exposure and health risk assessment of polycyclic aromatic hydrocarbon based on bioaccessibility:...

Dietary intake is a major pathway of human exposure to polycyclic aromatic hydrocarbons (PAHs), linking environmental contamination to food-chain transfer and health risks. However, conventional dietary exposure assessments often neglect bioaccessibility and the complexity of real dietary patterns, potentially biasing risk estimation and source attribution. In this study, an in vitro gastrointestinal digestion model was applied to quantify contamination levels and bioaccessibility of 15 PAHs in 43 commonly consumed foods across five categories, representative of typical urban diets. Compared with historical data, intensified contamination by certain highly toxic H-PAHs resulted in 1.15-18.5-fold increases in BaP_eq levels in fruits, meats, and cereals, underscoring the importance of integrated dietary assessment. PAHs bioaccessibility varied substantially (7.87-89.6 %), with the highest levels in meat (73.5 ± 23.4 %), revealing distinct matrix effects characterized by lipid facilitation and dietary fiber inhibition. Incorporating bioaccessibility into exposure modeling shifted the dominant dietary exposure source from cereals to meat, revealing that neglecting bioaccessibility may distort source attribution in exposure assessments. The bioaccessible dietary exposure dose (70.0 ng kg^-1 day^-1) of PAHs accounted for only 43.9 % of the total external exposure (160 ng kg^-1 day^-1), reducing the estimated proportion of the population at potential carcinogenic risk from 99.8 % to 45.4 %. These findings highlight the mechanistic importance of bioaccessibility in accurately evaluating internal exposure and identifying true dietary exposure sources. The systematic PAHs bioaccessibility dataset and integrated exposure model developed here provide a scientific basis for optimizing exposure assessment frameworks and guiding precision-oriented food safety management and risk control strategies.