Evaluation of petroleum activities and pollution indices on heavy metals levels in the sediment of Epie Creek, Yenagoa, Bayelsa State

The levels of heavy metals (Pb, Cd, As, Cu, Fe, Zn, Cr, Ni, Co, and Mn) in the surface sediments from Epie Creek were studied to determine the impact of petroleum and anthropogenic activities on the pollution load of the Epie Creek, Yenagoa, Bayelsa State. The levels of the heavy metals were measured using Flame Atomic Absorption Spectrophotometer (FAAS). The mean levels (mg/kg) of the heavy metals in the four locations were found to be in hierarchical order of Cr > Cu > Fe > Pb > Zn > Ni > Mn > Co > As > Cd. The control sample (location 4) has the lowest value of metal concentrations while, location 3 recorded the highest, indicating the influence of the petroleum and other anthropogenic activities on the surface sediment of the Creek. The source connectivity of these metals was supported by Spearman’s Correlation Analysis where most of the metals exhibited strong positive relationship, pointing to the same anthropogenic sources. Pollution indices study revealed that all of the metals have low contamination status except Cd that was highly contaminated. The geoaccumulation index values revealed that all the metals are practically unpolluted except Fe which ranked from moderately to extremely polluted in location 2, 3 and 1 respectively. The potential ecological hazard factors were in the order of Cd > Cu > Fe >Pb > As > Co >Cr > Ni > Zn > Mn > Fe. Among the four studied locations, location 3 has the highest metal levels and poses the greatest hazard risk. Therefore, the government of Bayelsa state and Nigerian Midstream/Downstream Petroleum Regulatory Authority (NMDPRA) should monitor and regulate the siting of petrol stations at Creeks and river bank; and also enact laws to stop indiscriminate dumping of wastes in the Epie Creek.