Mapping the dietary exposure risk of per- and polyfluoroalkyl substances (PFASs) from seafood consumption in Yangtze River Delta Urban Agglomeration, China

Seafood consumption is not only deeply embedded in dietary structures but also serves as a key pathway for human dietary exposure to per- and polyfluoroalkyl substances (PFASs). However, probabilistic dietary risks in high seafood consumption regions remain unclear. This research presents PFASs occurrence, bioaccumulation, and trophodynamics in the East China Sea (ECS), and evaluates age-group specific dietary exposure in the Yangtze River Delta Urban Agglomeration (YRDUA). PFASs were ubiquitous in seawater and organisms, with cephalopods and shrimp showing the higher concentrations. The perfluorooctane sulfonate (PFOS) replacement, 6:2 chlorinated polyfluoroalkyl ether sulfonate (6:2Cl-PFESA), and its precursor perfluorooctane sulfonamide (PFOSA) exhibited biomagnification potentials comparable to those of legacy long-chain PFASs, challenging the assumption that PFASs alternatives are safer. Risk quotient analysis further indicated that 6:2Cl-PFESA and some long-chain PFASs, such as perfluorotridecanoic acid (PFTrDA), perfluorodecanoic acid (PFDA) posed higher ecological risks to invertebrates than to fish. Monte Carlo based risk mapping revealed substantial heterogeneity across age groups and a clear north–south geographic gradient within the YRDUA, with children aged 2 to 6 years in northern cities and adults in southern cities exhibiting the higher exposure levels. These findings offer a scientific basis for targeted exposure management and policy intervention.