Health risks of exposure to organotin compounds via seafood consumption after their legal ban.

Organotin compounds (OTs), persistent environmental toxicants, were historically used in antifouling paints and have been banned on vessel hulls in Hong Kong since 2017. This study tested the hypothesis that OTs in seafood from Hong Kong waters, along with their associated dietary human health risks, declined six years post the legislation and enforcement. Analysis of 23 marine species collected in 2023, including molluscs, crustaceans, and fishes revealed total OTs concentrations of 11.8-747 ng/g ww, with the highest in benthic feeding fish Gerres septemfasciatus (747 ± 133 ng/g ww) and the croaker Johnius taiwanensis (696 ± 158 ng/g ww). Following the implementation of legislation, OTs in four commercially important fish species decreased significantly (p < 0.05) by 73.2-95.7%, supporting the effectiveness of regulatory measures. Triphenyltin (TPT), accounting for 32.7-96.4% of total residues across species, dominated the OTs composition in more than 80% marine organisms in this study, and exhibited significant trophic magnification in the marine food web with a trophic magnification factor of 8.61. Dietary exposure to total OTs through seafood consumption was estimated at 1.07 to 525 ng/kg bw/day, yielding a hazard index of 0.001-0.93, which is below the safety threshold of 1 for general adults. However, high consumption of fish species with high TPT concentration (e.g., G. septemfasciatus and J. taiwanensis) could increase health risk. These findings demonstrate the effectiveness of regulatory intervention, confirm the persistent ecological risk posed by TPT due to biomagnification, and highlight the need for continued monitoring to safeguard ecosystem and public health.