Ecological risk assessment of the impact of trace metal contamination on the benthic fauna and sediment of River Siluko, Edo State, Nigeria

This study evaluated the potential ecological and human health risk of trace metal pollution in sediment and benthic fauna (Pila ampullacea) of River Siluko. Result showed trace metal contamination of both sediment and P. ampullacea, with concentration profile of Fe > Zn > Cu > Cr > Mn > Co > Ni > Pb in sediments, and Fe > Zn > Cu > Mn > Ni > Co > Cr > Pb in P. ampullacea. Contamination factor values for Zn, Cu, Mn, Cr, Co, Ni and Pb were of low degree contamination (CF < 1) and Fe was of very high degree of contamination (CF > 6). The contamination degree (CD) values of the study Stations indicate a very high degree of sediment contamination from trace metals (CD ≥ 24). Potential ecological risk index (PERI) values classified the study stations 1, 2, 3 and 4 as of low ecological risk (PERI ≤ 150). Toxic Response Index Values (TRI) indicate no risk to aquatic organisms (TRI ≤ 5). Human health risk assessment associated with the consumption of contaminated P. ampullacea indicated non – carcinogenic risk (HI > 1) and carcinogenic risks to consumers, as the integrated carcinogenic risk (ICR) value classified the consumption of the edible part of P. ampullacea as extremely high risk (Grade VII) to consumers. The need for exigent actions to be taken in the abatement and regulation of identified anthropogenic activities responsible for the release of these metals into River Siluko is recommended.