Arsenic species in terrestrial fungi and lichens from Yellowknife, NWT, Canada

Levels of total arsenic and arsenic species were determined in fungi collected from Yellowknife, NWT, Canada, an area that has been affected by past mining activities and elevated arsenic levels, Lichens (belonging to Cladonia and Cladina genera), as well as the mushrooms Coprinus comatus, Paxillus involutus, Psathyrella candolleana and Leccinum scabrum, were studied for the first time, Most of the fungi contained elevated arsenic levels with respect to data found in the literature for background levels. Minor amounts of arsenobetaine were found in all lichen samples. The major water-soluble arsenic species in the fungi mere inorganic arsenic for lichens and Psathyrella candolleana, arsenobetaine for Lycoperdon pyriforme and Coprinus comatus, and dimethylarsenate for Paxillus involutus and Leccinum scabrum. A large proportion of water-soluble arsenic in Paxillus involutus occurred as an unknown compound, which did not co-chromatograph with any of the available standard arsenic compounds. Low proportions of water-soluble arsenic species (made evident by low extraction efficiencies) were observed in the majority of fungi studied. Arsenic that is not extracted may be bound to lipids, cell components or proteins, or might exist on the surface of the fungus as minerals. Copyright (C) 2000 John Wiley & Sons, Ltd.