Quantification of Heavy Metal Accumulation in Edible Wild-Mushrooms in Copperbelt and Western Provinces of Zambia

Abstract

The mushrooms are highly regarded as one of the most nutritious foods across the globe but also recognized bio-accumulators of heavy metals. The nature and level of industrial activities are continually changing and affecting the environment adversely. The mushrooms are not an exception and may inevitably have heavy metal contaminations. In this vein, this study aimed to determine heavy metal (Cu, Ni, Co, Zn, Pb, and Cd) uptake levels in wild edible mushrooms from the sites with different economic activities. The wild mushrooms considered for this study included Tente (Amanita Zambiana), Ichikolowa (Termitomyces Titaniscus), and Kabansa (Lactarius Tataniscus). The analysis of heavy metal concentration was carried out using atomic absorption spectrometry (AAS). For the selected mushrooms, concentration ranges (mg·kg-1 total dry weight (dw)) of 46.90 - 141.80 for Cu, 0.10 - 6.60 for Cd, 1.10 - 2.00 for Pb, 19.00 - 38.90 for Zn, 1.00 - 3.40 for Ni, and 44.80 - 79.70 for Co were obtained. However, for the respective soil samples, concentration ranges (mg·kg-1·dw) of 51.00 - 279.40 for Cu, 1.00 - 99.50 for Cd, 8.00 - 10.00 for Pb, 22.80 - 209.10 for Zn, 9.00 - 33.70 for Ni, and 60.00 - 111.90 for Co were obtained. To a certain degree, the concentrations reflected the impact of diversity in the surrounding activities. This study discovered that for the selected mushrooms, the contamination level of cadmium, cobalt, nickel, and copper exceeded the World Health Organization (WHO)/FAO (Food and Agriculture Organization) recommended limits. Although some minor aberrations from the prescribed limits were also observed in the case of copper and nickel. Further, the data established that the heavy metal concentrations in respective soils are not the sole determinant of concentrations in mushrooms. Thus, these findings merit attention as, in some cases, the extent of contamination has exceeded the WHO permissible limit, and it may pose a health risk to consumers.