| Summary: | Major, minor and toxic elements were determined by flame atomic absorption spectrometry and flame photometry in edible canned, wild and cultivated oyster mushrooms grown in cotton waste, wheat straw and wood waste substrates in Mekelle, Tigray, Ethiopia. Dry ashing using mixtures of HNO3:H2SO4:H2O2 (1:1:1 ratio) was used for digestion. The mean concentrations (mg/kg) of the studied elements in the mushroom samples were ranged from 964.66 to 4180.33, 2652.66 to 19918.66, 22.00 to 34.64, 16.00 to 30.38, 34.13 to 621.06, 40.25 to 120.91, 8.40 to 34.33, 4.22 to 30.63, 1.94 to 2.52 and 1.53 to 2.17 for Na, K, Ca, Mg, Fe, Zn, Cu, Mn, Cd and Pb, respectively. There were significant differences (p < 0.05) in the K, Fe, Zn and Mn levels of the mushroom samples which may be attributed to substrate variations. Moreover, significantly high correlations were observed between Na-K, Ca-Cd, Fe-Mn, Zn-Cu, Zn-Pb, Cu-Pb and Cd-Pb. Most of the results of this study were in good agreement with WHO recommended limits. However, the concentrations of Na and Cd in canned mushroom and all elements grown in wood substrate were recorded above the WHO recommended limits. The results of this study showed that, with the exception of canned and wood waste grown, the mushrooms can be used for human diets because of their acceptable content of many essential and minor elements and low content of toxic metals.
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