Heavy Metal Concentrations in Soil and Green Vegetables (Vigna unguiculata) around Volcanic Mountain of Oldoinyo Lengai, Arusha, Tanzania

The aim of this work was to assess heavy metal concentrations of samples collected from areas around a volcanic mountain in Tanzania. Fifty five soil samples and 10 samples of bean leaves were analysed using Energy Dispersive X- ray Fluorescence spectrometry (EDXRF). The concentrations of heavy metals in the samples are presented, statistical analysed and compared with control. The concentration in bean leaves are also compared with the maximum tolerable limits set by FAO/WHO to assess their safety for consumption. The results from this study show that high concentration of elements in both soils and bean leaves samples from Oldoinyo Lengai areas might be associated with frequently eruptions of the volcanic mountain of Oldoinyo Lengai. Hence, farming in Oldoinyo Lengai areas is introducing heavy metals in the food chain.