Intake rates of methylmercury in the Belgian population: Evolution over 40 years

Methylmercury (MeHg) is one of the most toxic compounds, it bioaccumulates and biomagnifies along the food chain and finally damages human's nervous system. Knowing that the main intake route for MeHg in humans is through fish consumption, intake rates were studied in various countries, but not in Belgium. Based on Hg and MeHg measurements in various fishes, mainly from North Sea catches, in combination with the national food consumption surveys, we could calculate daily Hg and MeHg intake rates for the Belgian population in 1975, 1997 and 2014-2021. These values are then compared with daily intake values reported by other countries and with the acceptable daily intake (ADI) values recommended by international organizations. Daily Hg and MeHg intake rates decreased strongly between 1975 and the 2 later periods: while average intake rates are all below the ADI norms, this is not the case for the 95th percentile rates because they exceed or are very close to the ADI values. Since daily MeHg intake rates correlate well with hair and blood concentrations, these were used as a good proxy of MeHg intoxication and were related to health effects observed in children, adolescents, adults and elderly persons living in Belgium via biomonitoring.