Major and trace elements in sclerotium of Pleurotus tuber-regium (Ósū) mushroom—Dietary intake and risk in southeastern Nigeria

This paper presents the results of the determination of Ag, Al, Ba, Ca, Cd, Co, Cr, Cu, Fe, Hg, K, Mg, Mn, Na, Ni, P, Pb, Rb, Sr and Zn in 30 specimens of the sclerotia of Pleurotus tuber-regium mushroom from two markets in southeastern Nigeria. The elements were determined by inductively coupled plasma atomic emission spectroscopy (ICP-AES). The K and Mg contents ranged from 500 to 10,000 μg/g (dry weight), followed by Ca and Na ranging from 19 to 1700 μg/g. The median concentrations of Fe, Zn, Al, and Mn were generally >10 μg/g, followed by Rb, Cu, Sr, Ba, and P with median between 1.1 and 11 μg/g, while Cr, Ni, Ag, Co, and Cd were <1 μg/g. The Hg concentrations were between 0.0033 and 0.15 μg/g. The Pb (0.05–2.2 μg/g) and Cd (0.0027–0.16 μg/g) contents were below EU limits for these metals in fungi, and thus safe for human consumption. Principal component analysis (PCA) showed that the concentrations of Ba, Ca, Mg, P, Rb and Sr in sclerotia did not vary considerably, depending on the sampling location, as did Cd, Cu, and Mn. PCA also revealed that the Hg and Pb in sclerotia could be related to anthropogenic sources.