Mercury content of wild edible mushrooms collected near the town of Augustow

Mercury content has been determined separately in the caps, stalks and whole fruiting bodies of thirteen species of popular wild edible mushrooms of the genus Boletus, Xerocomus, Leccinum, Suillus, Tricholoma, Rozites, Sarcodon and Cantharellus collected from Augustowska Forest, which is located in an unpolluted region in the northeastern part of Poland. The mushroom samples were collected in the summer and autumn of 1997 and 1998. Mercury measurements were by cold-vapour atomic absorption spectroscopy (CV-AAS) after wet digestion of the samples with concentrated nitric acid in closed PTFE vessels in a microwave oven. For each species 16 pooled samples were examined. Pinewood King Bolete Boletus pinophilus, King Bolete Boletus edulis, Scaly Tooth Sarcodon imbricatus,Gypsy Rozites caperatus. and Orange Birch Bolete Leccinum versipelle were the most contaminated with mean concentrations of 2,100 +/- 800; 2,300 +/- 1,100; 2,300 +/- 500; 1,200 +/- 300 and 720 +/- 380 in the caps and of 850 +/- 390; 1,000 +/- 500; 1,100 +/- 400; 470 +/- 150 and 420 +/- 170 ng/g dry matter in the stalks, respectively. For the other mushroom species examined the mean mercury concentration were less than or equal to 260 +/- 80 ng/g in the caps and less than or equal to 170 +/- 40 ng/g in the stalks, while the fruiting bodies of Common Cantharelle Cantharellus cibarius were the least contaminated, i.e. the range was between 8.0 and 24 ng/g and the mean 14 +/- 4. These findings suggest that mushrooms from Augustowska Forest indicate background contamination by mercury. Nevertheless, some of the mushroom species may posses a specific health risk when frequently consumed due to elevated mercury concentrations.