Mercury bioaccumulation in fish from French Polynesia: influence of trophic groups and risk assessment for consumers

Although fish is an important source of nutrients, including some of the healthiest proteins, long-chain fatty acids, and essential selenium, species at the top of the food chain often contain high levels of mercury (Hg). The provisional tolerable weekly intake (PTWI) of Hg from fish consumption is calculated based on the total concentration of Hg, assuming that all Hg is in the form of organic methylmercury (MeHg). However, recent findings indicate that some fish species, even top predators, may have high total Hg concentrations but very low proportions of MeHg. In this context, a study was conducted to monitor the concentrations of total Hg and MeHg in the edible flesh of various fish species from French Polynesia. These results, complemented by trophic level data, provide a clearer understanding of the MeHg/Total Hg ratio in fish a region where fish consumption is high. Detailed discussions will also address the potential risk assessment aspects.