Environmental Risk Assessment of Heavy Metals in Sediment of Nun River around Gbarantoru and Tombia Towns, Bayelsa State, Nigeria

Abstract

This study evaluated the environmental risk assessment of sediment heavy metals of Nun River at Gbarantoru and Tombia town in Bayelsa state, Nigeria. Sediment samples were collected in triplicate from three locations (viz: Location A around oil and gas installations, B- Gbarantoru and C- Tombia town). The samples were dried, processed and heavy metals concentration was determined using atomic adsorption spectrometry. Heavy metals results in the sediment ranged from 0.005 – 0.012 mg/kg cadmium, 0.001 – 0.003 mg/kg chromium, 0.001 – 0.002 mg/kg cobalt, 0.001 – 0.032 mg/kg nickel, 0.007 – 0.017 mg/kg lead, 0.082 – 0.126 mg/kg zinc and 0.138 – 0.314 mg/kg iron. There was significant variation (P<0.05) among the different various locations. The heavy metals showed positive significant correlations (P<0.05). The results showed low to moderate risk for contamination factor, degree of contamination and pollution load index; low to moderate contamination for index of geo-accumulation. Over 50% of the heavy metals in the various locations had positive quantification of contamination, which suggest pollution due to anthropogenic activities. On the overall, the ecological risk was within low risk. Hence, there is the need for sustainable management of anthropogenic activities that could impact on water and sediment quality.