ABSTRACT
Heavy metals occur naturally in soil and vary in content between regions. The study aimed at evaluating the status of heavy metals in soil and crops cultivated along Ikpoba river bank
The study was conducted on bulked soil samples collected from Ikpoba river bank and fallow land in the University of Benin. The particle size distribution, some soil chemical properties (pH, organic carbon, organic matter, exchangeable bases, total nitrogen, and available Phosphorus), were determined using standard methods. Fluted pumpkin and Amaranthus leaves were collected from the river bank and analyzed for some heavy (Fe, Cu, Mn, Zn, Pb and Cr) metals. The soil sample from the river bank and fallow land were analyzed of some heavy metals using double acid extraction method. Data collected were analyzed at P ≤ 0.05 using Genstat statistical package (12th Edition).
The results showed that the soils (River soil and fallow land) were slightly acidic, the river soil was higher in some important soil parameters (organic carbon, organic matter, total Nitrogen, Calcium and Magnesium) when compared to the fallow land. Lead (Pb) was not detected, but copper (Cu) and chromium (Cr) were high in the plant (fluted pumpkin and Amaranthus) leaves. The mean Cr content of the river soil was above critical value of 40 mg/kg reported by United States environmental protection agency (USEPA). The correlation study revealed the influence of soil properties on the availability of some heavy metals studied. Considering the high content of Cr in the soil, fluted pumpkin and Amaranthus leaf, it is recommended that, the river soil be checked for Cr to prevent excessive entry of Cr into the food chain through agriculture activity in and around the Ikpoba river bank.
