Idakwoji Precious Adejoh
The study was conducted to determine the heavy metal concentration in the soils and cassava (Manihot esculentus) leaves within the vicinity of a cement factory in North Central, Nigeria. The concentrations of Cd, Cu, Ni, Pb and Zn were determined using Atomic Absorption Spectroscopy (AAS) technique. Samples of soil and cassava leaves were collected from sites located at a maximum 0.5- 1 km from the factory while control samples were collected on sites located 3 km from the factory. Mean Cd contents in the soil and control soil samples were 1.22 ± 0.34 and 0.78 ± 0.16 μg/ g respectively. Mean values for Cu, Ni, Pb and Zn concentrations in the soil samples were 3.42 ± 0.70, 0.07 ± 0.02, 8.40 ± 2.48 and 0.04 ± 0.01μg/ g respectively while for the control sites, the mean values were 0.72 ± 0.09, 0.02 ± 0.07, 0.91 ± 0.04 and 0.02 ± 0.01respectively. Mean values for Cd, Cu, Ni, Pb and Zn concentrations in the cassava leaves were 0.02± 0.01, 0.93 ± 0.02, 0.39 ± 0.10, 0.30 ± 0.36 and 0.05 ± 0.02 μg/ g respectively while for the cassava leaves from the control site, the mean values were 0.01 ± 0.01, 0.02 ± 0.01, 0.36± 0.10, 0.02 ± 0.01 and 0.02 ± 0.01 μg/ g for Cd, Cu, Ni, Pb and Zn concentration respectively. With the exception of Ni and Pb, there were positive correlations between the soil and plant samples for all the metals in the investigated area. These relations were only significant for Ni which showed a negative correlation (r = - 0.78) (p< 0.05). Metal levels in both soil and cassava leaf samples were below the WHO/ FAO recommended limits.
