Mineral constituents in Leccinum scabrum from lowland locations in the central Europe and their relation to concentration in forest topsoil
ABSTRACT Leccinum scabrum is an edible mushroom common in European regions in the northern hemisphere. Macro and trace mineral constituents such as Ag, Al, Ba, Ca, Cd, Co, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, P, Rb, Sr and Zn were studied in L. scabrum and in the top soil collected from the same location underneath soil substratum. The “pseudo-total” and labile (extractable fraction of minerals) were measured to get insight into the levels, distribution between the morphological parts of fruiting bodies, potential for their bioconcentration by mushroom and evaluated for human exposure via consumption of the mushroom. The sampling sites include the Darżlubska Wilderness, Trójmiejski Landscape Park, Sobieszewo Island, Wdzydze Landscape Park and outskirts of the Kętrzyn town in Mazury from the norther part of Poland. Median values of K, Rb and P concentrations in dehydrated L. scabrum were for caps in range 27,000–44,000 mg kg−1, 90–320 mg kg−1 and 6,200–9,100 mg kg−1, and followed by Mg at 880–1,000 mg kg−1, Ca at 48–210 mg kg−1 and Al at 15–120 mg kg−1. The median concentrations of Cu, Fe, Mn and Zn in caps were in range 15–27 mg kg−1 db 38–140 mg kg−1, 5.3–27 mg kg−1 and 130–270 mg kg−1. For Ba and Sr, concentrations on the average were at ∼1 mg kg−1, and almost equally distributed between the caps and stipes of the fruiting bodies. L. scabrum mushrooms were low in toxic Ag, Cd, Hg and Pb, for which the median values in dried caps from five locations were, respectively, in range 0.48–0.98 mg kg−1 (cap to stipe index, QC/S, was 2.5–4.1), 1.0–5.8 mg kg−1 (QC/S 2.9–3.8), 0.36–0.59 mg kg−1 (QC/S 1.6–2.7) and 0.20–0.91 mg kg−1 (QC/S 1.2–1.9). Substantial variations in the concentrations of the “pseudo-total” fraction (extracted by aqua regia) or labile fraction (extracted by 20% solution of nitric acid) of the elements determined in forest topsoils were noted between some of the locations examined. The elements K, P, Cd, Cu, Hg, Mn, Na, Rb and Zn can be considered as those which were bioconcentrated by L. scabrum in fruiting bodies, while the rates of accumulation varied with the sampling location.