The sequence of the heavy metals (Fe, Mn, Zn, Cu, Pb, Cd and Cr) and total hydrocarbons (THC) in the water and tissues (gills, intestine and muscle) of an abundant and economically significant fish (Clarias gariepinus) harvested from Osse River were investigated from April, 2014 to September, 2015. Water and fish samples were collected from 4(four) chosen stations and were analysed for the levels of heavy metals and total hydrocarbons. The ecological risk of the study area and health risk indices of the fishes were assessed. Generally, accumulation of heavy metals and total hydrocarbons in the fish was gills > intestine > muscles (anomalous sequence). The sequence may pose some threats to the health of the consumers. Iron, zinc, copper, cadmium and THC showed significant health risk indices in the fish despite their insignificant ecological risk indices. Further in-depth study on the actual levels of risks to consumers is recommended
