Human health risk assessment of trace metals contamination in a tropical river

Levels of trace metals (Cd, Cr, Cu, Pb and Zn) were quantified in water, sediment and winkles (Pachymelania bryonensis and Pachymelania fusca mutans) in Akani Obio Uruan River, Nigeria during wet and dry seasons using standard procedures. Results revealed that mean levels (mg/l) of the metals in water ranged from 0.016 for Cr to 0.087 for Cd in wet season and 0.010 for Cu to 0.082 for Zn in dry season. In sediment, the metals levels (mg/kg) ranged from 0.002 for Pb to 0.161 for Zn in wet season and 0.001 for Pb to 0.438 for Cu in dry season. In winkles, the metals levels (mg/kg) ranged from 0.002 for Pb to 0.069 for Cd and for Cu in the wet season, and 0.001 for Pb to 0.058 for Cd and for Cu in the dry season. Estimated human health risk from each metal contamination due to consumption of the water, dermal absorption through swimming and consumption of winkles gave each of hazard quotient (HQ) and hazard index (HI) values of less than one (< 1), indicating no risk since the levels of contamination in each case are not likely to cause any adverse health effects in humans.