Trace Metals Characterization in Environmental Media: A Case Study of Cement Production Area Ewekoro, Southwest, Nigeria

Abstract

Environmental quality deterioration resulting from increase in the level of potentially toxic metals is becoming more pronounced, thus raising the question on safety status of our environment. Impact assessment and characterization of trace metals in the environmental media including groundwater, top soils, and tree barks in the vicinities of West African Portland Cement Company factory mill, Ewekoro, Ogun State, Nigeria was undertaken. The environmental samples were analysed for trace metals employing flame atomic absorption spectrometry (FAAS). The concentration of Cu, Cd and Fe detected in the groundwater ranged between 0.026 -0.082, 0.0038 -0.004 and 0.003-0.035 (mg/L) respectively. A decrease order in the level of metals level observed in the top soil is Fe > Pb >Ni > Cr > Cu > Cd, while that of tree barks samples is Fe > Cu > Cr > Pb > Ni > Cd. The saturated index (SI) obtained (through phreqC model) of the groundwater samples showed saturated to undersaturated with respect to CdSO 4 and FeSO 4 :7H 2 O, while SI was saturated to supersaturate with respect to CdCO 3 and FeCO 3 . Quality indices employed in analyzing soil data include enrichment factor, contamination factor and pollution load index. There is a buildup of trace metals in the environment (soil) particularly Pb. The levels of metals investigated are within the threshold limit set by the WHO health-based guideline for drinking water. Significant correlations were found to exist between Cd and Ni, Cr and Fe both in the tree bark and top soil samples, suggesting common source.