Mercury and its bioconcentration factors in Brown Birch Scaber Stalk (Leccinum scabrum) from various sites in Poland

The total mercury contents were determined in the carpophores of Brown Birch Scaber Stalk (Leccinum scabrum) and topsoil (0–10 cm) collected from 12 spatially distant sites across Poland. Mercury was measured by cold-vapour atomic absorption spectroscopy (CV-AAS) after nitric acid (mushrooms) or aqua regia (soil) digestion of the samples. The caps, depending on the site, had total mercury concentrations from 0.38 ± 0.23 to 1.2 ± 0.4 μg/g dm (median 0.36–1.2 μg/g dm), and stalks from 0.17 ± 0.08 to 0.72 ± 0.20 μg/g dm (median 0.17–0.72 μg/g dm). Overall-mean mercury contents for 240 caps and stalks were 0.63 ± 0.38 (0.072–2.0 μg/g dm) and 0.32 ± 0.20 (0.028–1.2 μg/g dm), respectively. The total mercury content in top soil layer (0–10 cm) at 12 sites, after hot aqua regia extraction, averaged 0.026 ± 0.010–0.066 ± 0.018 μg/g dm. The BCF values of total mercury in caps of Brown Birch Scaber Stalk from the particular sites ranged from 14 ± 5 to 20 ± 4 (total mean was 16 ± 5, and median 18), in stalks from 6.0 ± 4.0 to 11 ± 1 (total mean was 8.3 ± 3.1, and median 8.1). In human feeding, wild mushrooms are usually only a small part of the total diet, so consumption of Brown Birch Scaber Stalk collected from the background sites in Poland, or elsewhere in Europe, as regards mercury content, could be considered safe.