STM Article Repository

Soil contamination by heavy metals is of great concern with respect to human health risks, groundwater contamination, phytotoxicity to plants, adverse effects on microbial activity and diversity, long-term effects on soil fertility and depreciation of land. Soil samples were obtained with the aid of soil Augar within a depth of 0 – 20 cm from the vicinity of the two selected dumpsites in Benin City, Edo State Nigeria. The soil samples were assessed for some physico-chemical properties using standard methods. Maize plants found growing in the dumpsite and control areas were also sampled, partitioned into leaves, stems, and roots prior to analysis in the laboratory for heavy metals determination using atomic absorption spectrophotometer (AAS). The soil sample showed Zn, Cu, Cd, Pb and Cr levels ranging from 42.66-243.81, 2.16-21.41, 0.35-2.59, 1.11-7.76 and 2.99-10.99 mg/kg respectively. Pollution indices such as contamination factor, contamination degree and pollution load index of the heavy metals analyzed were calculated and their values varied among the heavy metals and between the dumpsites. Concentrations of the metals in the dumpsite soil and plant were found to be higher compared to those of the control sites. Significant differences of heavy metals accumulations were observed per plant parts, roots having the highest concentrations. The translocation factor, biological concentration factor and biological accumulation coefficient values of the plant species varied for all the metals. These results imply that the dumpsites have associated human health and ecological risks.