Evaluation of Heavy Metal Concentrations and Associated Human Health Risks in Wild Oyster Mushroom (Pleurotusostreatus) from Southeastern Nigeria

Abstract

The detrimental effects of heavy metals on food substances are concerning because they pose a threat to human health and food security in general. This study evaluated heavy metal concentrations and assessed the associated human health risks in wild oyster mushroom (Pleurotusostreatus) from southeastern Nigeria. Using stratified random sampling method, representative mushroom samples were collected from the five states of southeastern Nigeria (Abia, Anambra, Ebonyi, Enugu and Imo). Heavy metals were measured with a Varian Spectra AA 200 Atomic Absorption Spectrophotometer. Duncan's Multiple Range Test (DMRT) was used to differentiate significant means at a 5% probability level after the data was analyzed using analysis of variance (ANOVA). HMs (Pb, Ni, Cr, Fe, Cd, As, Zn, Cu, and Hg) in the mushrooms varied significantly across the locations with their distribution decreasing in the order of Zn > Cu > Fe > Pb > Ni > Cr > Hg > Cd > As. Greater concentrations of most of the heavy metals including Cd(0.03±0.01-1.41±0.02 mgkg-1), As (0.02±0.07-0.43±0.001 mgkg-1), Cu(9.63±0.07-23.07±0.18 mgkg-1) and Hg(0.04±0.06-1.95±0.07 mgkg-1) were obtained in Ebonyi, Anambra had more concentrations of Fe(1.82±0.07-3.86±0.06 mgkg-1) and Zn(18.56±0.5-50.64±0.04 mgkg-1), Enugu state had more concentrations of Pb(1.01±0.02-3.30±0.06) and Ni(0.29±0.05-1.49±0.013 mgkg-1) whereas Cr(0.34±0.001-1.73±0.03 mgkg-1) was greater in Abia state. Additionally, most of the heavy metals' carcinogenic health risk had values below 10-4, which generally suggested an acceptable carcinogenic risk for both adults and children. Although most risk assessment findings showed uncontaminated to low contamination, indicating that the sampled mushrooms are safe, it is nevertheless vital to maintain a careful eye on the heavy metal profiles because heavy metals can bioaccumulate in living tissue over time.