The content, bio-accessibility and in vitro bioavailability of lead species in various seafood samples collected from...

Seafood ingestion is one of main internal pathways for human lead exposure. Accurately assessing the health risks posed by seafood's lead remains challenging, owing to lack of bio-accessibility/bioavailability data for Pb species. Herein, the content and bio-accessibility of Pb species in 50 different seafood samples, and in vitro bioavailability of Pb species in various seafood matrices were investigated. Results revealed that the distribution of Pb species in seafood seems to exhibit types/species-specific variations and regional characteristics. All seaweed and shellfish samples contained only Pb²⁺, while fish from some regions contained both Pb²⁺ and trimethyl lead (TML), with other regions containing only Pb²⁺. Pb species did not undergo transformation during gastrointestinal digestion and Caco-2 cells ingestion. The mean Pb²⁺ bio-accessibility varied in the following order: seaweed > shellfish ≈ fish, while the mean bioavailability of Pb²⁺ and TML varied as order: fish > shellfish > seaweed. TML exhibited both higher bio-accessibility and bioavailability than Pb²⁺. Simulated calculation revealed it is crucial to detect Pb species and to consider the bioavailability of Pb species for accurately assessing Pb-related health risks from seafood ingestions. However, for seafood containing both Pb²⁺ and TML at similar levels, the Pb-related health risks may be preliminary screened/roughly assessed using total Pb, without need to consider Pb species and bioavailability. This offers a simple "screening-level" method to ensure the safety concerning seafood's lead. Results of this study offers valuable bio-accessibility/bioavailability data for Pb species across different types of seafood, and novel insights for accurate evaluation of Pb-related health risks from seafood.