Arsenic species in arsenic-accumulating mushrooms (Sarcosphaera coronaria, Laccaria amethystina, Sarcodon imbricatum, Entoloma lividum, Agaricus haemorrhoidarius, Agaricus placomyces, Lycoperdon perlaturn) were determined. HPLC/ICP MS and ion-exchange chromatography-instrumental neutron activation analysis (NAA) combinations were used. The remarkable accumulator Sarcosphaera coronaria (up to 2000 mg As kg-' dry wt) contained only methylarsonic acid, Entoloma lividum only arsenite and arsenate. In Laccaria amethystina dimethylarsinic acid was the major arsenic compound. Sarcodon imbricatum and the two Agaricus sp. were found to contain arsenobetaine as the major arsenic species, a form which had previously been found only in marine biota. Its identification was confirmed by electron impact MS.

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The selenium contents of 83 species of wild mushrooms were determined by oxygen combustion of the sample, followed by conversion of selenite to bromopiazselenol and final estimation by electron capture gas-liquid chromatography. Selenium concentration were found to range from 0.012-20.0 mg/kg dry weight. Selenium content was species-dependent. High concentrations were found in Agaricaceae and in certain Boletaceae of the genus Tubiporus, whereas in Russulaceae, Amanitaceae and Cantharellaceae selenium-rich species were absent or rare. Ascomycetes and all mushrooms growing on wood had a very low selenium content. The highest selenium concentrations (up to 20 ppm) were found in Boletus (Tubiporus) edulis, a most popular edible mushroom. Analyses of various parts of carpophores of B. edulis, Suillus luteus and Amanita muscaria indicate that in all three species the stalk contains less selenium than the fleshy part of the cap. In Boletus and Suillus the highest selenium content was found in the tubes.

In 50 mushroom species (56 samples) from Slovenia, Switzerland, Brazil, Sweden, The Netherlands and USA, total arsenic was determined by radiochemical neutron activation analysis (RNAA). Arsenic concentrations ranged from 0.1 to 30 μg g−1 (dry mass). Arsenic compounds were determined in methanol extracts from the mushrooms by HPLC–ICP–MS. The aim of the study was not only to quantify arsenic compounds in mushrooms but also to uncover trends relating the methylating ability of a mushroom to its taxonomic or evolutionary status. The main arsenic compound found in many mushrooms (various puffballs, Agaricales and Aphyllophorales) was arsenobetaine. Arsenate [As(V)] was the main arsenic species in Laccaria fraterna and Entoloma rhodopolium and arsenite [As(III)] in Tricholoma sulphureum. A mixture of arsenite and arsenate was present in Amanita caesarea. Dimethylarsinic acid (DMA) and methylarsonic acid were present in many mushrooms, but generally as minor components. In Laccaria laccata, Leucocoprinus badhamii and Volvariella volvacea, DMA was the major metabolite. Arsenocholine (AC) and the tetramethylarsonium ion were present in a few species, generally at low concentrations, except for Sparassis crispa, in which AC was the main compound. Tri‐ methylarsine oxide was not found in any of the mushrooms. In some species small amounts of unknown compounds were also present. The possible taxonomic significance of the metabolite patterns and the predominance of arsenobetaine in more advanced fungal types are discussed. © 1997 John Wiley & Sons, Ltd.

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