Assessment of Some Heavy Metals Concentration in Soil and Moringa Oleifera Samples from Gwarzo Town, Kano State, Nigeria

Abstract

The presence of heavy metals in plants is of significant concern owing to their toxicity to humans and ability to accumulate in food chains.  This study was conducted to assess the levels of heavy metals in Moringa oleifera plant and soil within Gwarzo Town, Kano State,  Nigeria via X-ray Fluorescence Technique. Leaf extracts from the plant, Moringa oleifera, and samples of the soil supporting the plant were collected from different parts of Gwarzo town. Six heavy metals namely: Fe, Cu, Ni, Cd, Mn, and Cr were determined. The results  showed that the mean concentration of Fe, Cu, Ni, Cd, Mn, and Cr were 669.95 mg/kg and 4998.4 mg/kg, 4.63 mg/kg and 1.37 mg/kg,  194.0 mg/kg and 19.26 mg/kg, 50.85 mg/kg and 1.25 mg/kg, 1.42 mg/kg and 5.56 mg/kg, and 44.24 mg/kg and 129.7 mg/kg, for plant and soil samples respectively. The Fe and Cr concentration values for both plant and soil samples were above the acceptable values of 27  mg/kg and 100 mg/kg set by World Health Organisation. Considering the results obtained from this study, plants need proper treatment  before consumption. Also, farms should not be sited near the highway and factories to avoid the accumulation of heavy metals.