Trace Metals and Safe Consumption of Edible Fungi from Upper-Katanga (DR Congo)

Abstract In Upper Katanga region (Democratic Republic of the Congo) Wild Edible Fungi (WEF) are an important source of food and income. This study is the first to present the trace metal content of six edible mushrooms collected from the mining region around Lubumbashi. Samples were taken in places where local people collect fruit bodies for consumption. Inductively Coupled Plasma Spectrometry (ICP-OES,) was used to determine concentrations of ten trace metals (Al, Cr, Cu, Co, Pb, Cd, Fe, Ni, Mn and Zn) in Amanita loosii, Amanita pudica, Cantharellus congolensis, Cantharellus densifolius, Cantharellus platyphyllus, and Cantharellus ruber. Concentrations of Cr, Ni, and Pb are under the EU norm in all six species, but values for Al, Co, Cu, Fe, Mn, and in some cases also for Zn or Cd are above. Significant differences between species were observed for Al, Cd, Co, Cr, Cu, Mn, and Zn. Large variations for Al and Fe concentrations are likely partly explained by soil dust contamination, as these two elements are very abundant in soils. Co, Cu, and Mn are abundant in soil samples of MMG-Kinsevere, Cr is abundant in soil samples of Mikembo. Cd concentrations are highest in Amanita while Al and Co reach the highest concentrations in Cantharellus species. Recommended tolerable, monthly, weekly or daily intake of metals and average metal concentrations in edible fungi were used to calculate the safe weekly consumption (SWC, in kg fresh weight/week) for a 60 kg person. Cd limits the consumption of A. loosii and A. pudica to 0.6 kg-1.2 kg FW/week, Fe limits Cantharellus congolensis and C. platyphyllus to 2.2 kg-2.5 kg FW/week and Al limits C. ruber and C. densifolius to 3.5 kg-3.8 kg FW/week. Recommendations are listed to further reduce the intake of metals through the consumption of wild edible fungi.