Mineral composition and heavy metal accumulation capacity of Bay Bolete (Xerocomus badius) fruiting bodies collected near a former gold and copper mining area

Concentrations of Ag, Al, Ba, Ca, Cd, Co, Cr, Cu, Fe, Hg, K, Mg, Mn, Na, Ni, P, Pb, Rb, Sr and Zn were determined in edible Bay Boletes and beneath top soils from a forested mine dump at the site of a medieval gold and copper mine near the town of Złotoryja in southern Poland and in mushrooms from a reference site in Tucholskie Forest in the north of Poland. Bay Bolete mushrooms collected from Złotoryja site accumulated in their flesh more Ag, and Pb and also Ba and Mn but less P and Rb (p < 0.01–p < 0.05; Mann–Whitney U test) compared to mushrooms from a reference site in Tucholskie Forest. Elevated content of Ag and Pb in mushrooms from the Złotoryja site was clearly a result of topsoil contamination with the metals there. At both sites the most abundant in mushrooms were P, K and Mg (> 700 μg g− 1 dw), followed by Na, Rb and Zn (around 200 to 400 μg g− 1 dw) and next by Al, Ca, Cu, Fe, Mn and Ag (> 1 μg g− 1 dw at Z site and < 1 μg g− 1 dw at TF site) and by Ba, Cr, Cd, Ni, Pb, Sr and Co (< 1 μg g− 1 dw). Bay Bolete mushrooms from both sites if eaten in a typical volume (300 g) daily for a week (300 g × 7) during a mushrooming season are safe in terms of Hg, Cd and Pb content and doses taken. Silver was highly elevated in caps of Bay Boletes at Złotoryja but no tolerance limit is established for this metal in foods.

► Mineral compounds in Bay Bolete from ancient Au and Cu mine and reference site
► A mine dump site showed more Ag, Cu, Hg and Pb than at reference area.
► Cd, Cu, Mg, P and Zn are more abundant in caps than stipes of Bay Bolete.
► Ag at elevated concentration was in mushrooms from mine dump site.
► Cd, Pb and Hg content of mushrooms was similar for both sites.