Evaluation of essential elements and heavy metal levels in fruiting bodies of wild mushrooms and their substrate by EDXRF spectrometry and FAA spectrometry.

Abstract

The essential elements (Zn, Cu, Fe, K, Mn, Mg, Se) and heavy metals (Cd, Cr, Ni, Pb, Ti, Sr, Co, Bi) contents of eight wild mushrooms (Amanita vaginata, Amanita rubescens, Amanita phalloides, Armillariella mellea, Armillariella tabescens, Agaricus campestris, Hypholoma fasciculare, Hypholoma pudorinus) and soil samples of ten forest sites from Dambovita County, Romania, were determined. The elements were determined by Flame Atomic Absorption Spectrometry (FAAS) and Energy Dispersive X-ray spectrometry (EDXRF) in 48 samples of eight fungal species and 32 underlying soil samples. The elements in soil, especially heavy metals, are specific to the acidic soils of the Romanian forest lands and are influenced by industrial pollution. In fruiting body of these mushrooms, the highest mean concentration of macroelements (dry mass basis) was found for K, Zn and Fe. Some metals were substantially concentrated at higher levels in the fruiting bodies than in the soil. The mean concentration of heavy metals (Cd, Cr, Ni, Pb, Sr, Co, Bi) was higher in mushrooms which have been collected on forest sites near urban settlements. For example, the highest cadmium content was observed in Hypholoma fasciculare, the important chromium level was obtained in Armillariella mellea and nickel was founded in high concentration in Hypholoma pudorinus. Lead at highest concentration was determined in soil of Amanita vaginata, Amanita phalloides and Amanita rubescens. The amount of zinc in the Amanita vaginata, Amanita phalloides, Amanita rubescens, Armillariella mellea, Armillariella tabescens and Agricus campestris was variable from 108.7 - 135.7 mg/kg d.w., being higher comparative with the content of zinc from Hypholoma fasciculare, and Hypholoma pudorinus( 86.4 mg/kg d.w. and 55.8 mg/kg d.w., respectively). The studied mushrooms are very good bioaccumulators of zinc, calcium, magnesium, selenium and copper; the smaller affinity for titanium, strontium and bismuth were observed at all studied wild mushrooms. Analytical possibilities of EDXRF and FAAS analytical methods were compared and the heavy metal transfer from substrate to mushrooms was studied. The coefficient of accumulation of essential elements and heavy metals was calculated as well. Heavy metal contents of all analysed mushrooms were generally higher than previously reported in literature.