Mercury in bay bolete (Xerocomus badius): bioconcentration by fungus and assessment of element intake by humans eating fruiting bodies.

Concentrations of mercury (Hg) were determined in 221 specimens of bay bolete and in 221 samples of corresponding forest topsoil layer (0-10 cm) collected from 18 sites across geographically and industrially diverse regions of Poland in 2000-2008. Mercury concentrations in caps and stipes of bay bolete were strongly correlated (p < 0.0001), whereas the relationship between the Hg concentrations in soil and mushrooms varied depending on the sampling location. The bay bolete showed a lower bioconcentration potential of Hg at sites with elevated soil Hg concentrations and a higher bioconcentration at sites with lower Hg concentrations in soil. In view of Hg content, the consumption of bay boletes (caps or whole mushrooms) at the regions surveyed at least at a rate up to 2.5 kg per capita weekly in a mushrooming season is safe and will not result in exceeding of currently allowable Hg intake doses.