Heavy metals in edible mushrooms in Italy
The distribution of arsenic, cadmium, lead, mercury, and selenium was investigated in 1194 samples of 60 species of common, edible mushrooms collected mainly in the province of Reggio Emilia, Italy. The quantitative determination of heavy metals (mg/kg dry weight) was carried out by spectrophotometry, with the exception of Hg, which was determined by atomic absorption spectroscopy. The amount of arsenic accumulated in the samples studied was in general modest. Sarcosphaera eximia, on the other hand, may contain arsenic concentrations reaching 1000 mg/kg dry weight. Within the Agaricus Subgenus Flavoagaricus, only Agaricus nivescens contains amounts of cadmium inferior to the allowed maximum level. The Cd levels in samples of Amanita caesarea, Boletus edulis and Boletus pinophilus exceeded the maximum amount allowed. The content of cadmium in Agaricus macrosporus is roughly 50 times the maximum weekly dose recommended by the WHO. The average amount of lead present in all samples, was in general, below the the maximum allowed concentration. Agaricus bitorquis, Agaricus arvensis, Agaricus essettei, Agaricus albertii, B. pinophilus, Clitocybe geotropa, and Macrolepiota rachodes had high contents of Hg that were within the range 5–10 mg/kg dry weight. Mushrooms in general, but species in the B. edulis group, in particular, were rich in selenium. Accumulation of specific heavy metals could be species-specific and thus assume a taxonomic role but it has proved in our study to be unreliable as an ecological indicator.