Monitoring Toxins and Human Health Risk Assessment of Clarias Gariepinus from Nwangele River in Imo State, Nigeria

Abstract

Polycyclic aromatic hydrocarbons (PAHs) and heavy metals are ubiquitous environmental contaminants which have caused worldwide concerns as toxic pollutant. This study reports the concentrations of 8 PAHs and 4 heavy metals (Al, As, Pb, and Hg) in clarias gariepinus collected from Nwangele River in Imo State Nigeria. The mean concentration of heavy metals was between 0.06-2.67 mg/kg, with Arsenic having the highest concentration. Daily intake of heavy metals was estimated using daily fish consumption of 0.03643kg/person/day from literature. Referenced oral dose RfD for the four metals were: 0.043, 0.003, 0.004, 0.0001 respectively. Health Risk index (HRI) of heavy metals were < 1 for Al and Pb, but were very high for As and Hg. For PAHs, concentrations showed 13, 4.5, 36.6, 19.6, 80.9, 50.2, 5.1, and 22.4 mg/kg for fluorine, phenanthrene, anthracene, benzo(k) flouranthene, benzo(a) pyrene, benzo (b) flouranthene, pyrene, and dibenzyl (a-h) anthracene respectively. The study indicated that with reference to Al and Pb, fish from the river were safe for consumption. Conversely, the fish were unsafe with reference to concentrations of PAHs, As, and Hg. The study recommended prevention measures towards water pollution and consumer awareness of health hazard in consuming contaminated fish