Mercury and selenium in whole blood and serum in relation to fish consumption and amalgam fillings in adolescents

Mercury and selenium in whole blood and serum of 245 17-year old Swedish adolescents were analysed. The relationships between these elementsʹ concentrations and the consumption of fish as well as the number of dental amalgam fillings were studied. The geometric means (GM) of the mercury concentrations were 1.1 μg/L in blood and 0.43 μg/L in serum. The mean selenium concentration in blood was 110 μg/L and the GM of the serum selenium concentration 110 μg/L. Fish species with dietary restrictions due to elevated mercury levels (i.e. pike, perch, pikeperch, burbot, eel and halibut) were consumed on average 0.7 times/month and fish species without such restrictions 4.1 times/month. Despite this comparatively low fish consumption, the adolescentsʹ blood mercury concentrations were positively correlated with fish consumption. Of the adolescents, 39% had amalgam fillings (mean 2 ± 1.5). Serum mercury was influenced by the number of amalgam fillings, by fish consumption, blood and serum levels of selenium and the residential area. Blood and serum selenium concentrations were not influenced by fish consumption, but were positively associated with the serum mercury concentration.