Mercury in wild mushrooms and underlying soil substrate from Koszalin, North-central Poland

Abstract

Concentrations of total mercury were determined by cold-vapour atomic absorption spectroscopy (CV-AAS) in 221 caps and 221 stalks of 15 species of wild growing higher fungi/mushrooms and 221 samples of corresponding soil substrate collected in 1997–98 in Manowo County, near the city of Koszalin in North-central Poland. Mean mercury concentrations in caps and stalks of the mushroom species examined and soils varied between 30 ± 31 and 920 ± 280, 17 ± 11 and 560 ± 220, and 10 ± 9 and 170 ± 110 ng/g dry matter, respectively. Cap to stalk mercury concentration quotients were from 1.0 ± 0.4 in poison pax ( Paxillus involutus) to 2.8 ± 0.7 in slippery jack ( Suillus luteus). Brown cort ( Cortinarius malicorius), fly agaric ( Amanita muscaria), orange–brown ringless amanita ( A. fulva), red-aspen bolete ( Leccinum rufum) and mutagen milk cap ( Lactarius necator) contained the highest concentrations of mercury both in caps and stalks, and mean concentrations varied between 600 ± 750 and 920 ± 280 and 370 ± 470 and 560 ± 220 ng/g dry matter, respectively. An estimate of daily intake of mercury from mushroom consumption indicated that the flesh of edible species of mushrooms may not pose hazards to human health even at a maximum consumption rate of 28 g/day. However, it should be noted that mercury intake from other foods will augment the daily intake rates. Species such as the sickener ( Russula emetica), Geranium-scented russula ( R. fellea) and poison pax ( P. involutus) did not concentrate mercury as evidenced from the bioconcentration factors (BCFs: concentrations in mushroom/concentration in soil substrate), which were less than 1. Similarly, red-hot milk cap ( L. rufus), rickstone funnel cap ( Clitocybe geotropa) and European cow bolete ( S. bovinus) were observed to be weak accumulators of mercury. Fly agaric ( A. muscaria) accumulated great concentrations of mercury with BCFs reaching 73 ± 42 and 38 ± 22 in caps and stalks, respectively. Mercury BCFs of between 4.0 ± 2.3 and 23 ± 25 (caps) and 2.6 ± 1.9 and 14 ± 12 (stalks) were noted for the other mushroom species. Relatively great concentrations of mercury in fly agaric ( A. muscaria) were due to preferential uptake of this element by this species.