Source and Distribution of The Heavy Metals: Pb, Cd, Cu, Zn, Fe, Cr, and Mn in Soils of Bauchi Metropolis, Nigeria

摘要

In this research work the level and distribution pattern of the metals: Pb, Cu, Cd, Cr, Zn, Mn, and Fe were determined in soil of Bauchi Metropolis. Samples were collected from places of high anthropogenic activity such as automobile maintenance workshop (AMW), to places of low activity; the Residential areas (RA). Collection was done from surface to subsurface portion of the soil at the depth of 0 to 15cm at the beginning of raining season in the month of May/June 2017 to late September/October of the same year. Samples were analyzed using Atomic Absorption Spectroscopy (AAS) model AA240FS following digestion with aqua-regia. The results shows that, concentration of Pb ranged from 0.005±0.003 to 0.051±0.002 with highest level from the AMW whereas the lowest comes from the RA and it was not detected in BMP. Level of Cd ranges from 0.002±0.001 to 0.004±0.011, the highest level comes from the AMW, the lowest from the HW, it was not detected in RA and BMP. For Fe, the concentration ranged from 9.559±0.211 to 10.630±0.0231, the highest level was observed along the HW followed by the BMP, the lowest level however comes from the AMW. Cu was only observed in AMW with the level 0.007±0.021. The level of Cr ranged from 0.009±0.005 in the BMP to 0.026±0.003 along the HW. The concentration of Mn ranges from 0.477±0.0121 in the BMP to 0.980±0.121 in the RA. The concentration of Zn ranges from 0.053±0.021 in BMP and RA to 0.252±0.101 in the AMW. All measurements were in ppm. The metals were found randomly distributed within the Metropolis. Flooding coupled with gravity of the rain and the physiochemical property of the soil might have contributed to the level and distribution pattern of the metals within the Metropolis. The resea rch also indicates that, anthropogenic activity is not the main source of the heavy metals but it is additive.