Mathematical Modelling of Heavy Metal and PAH Contamination in Seafood from Okoroba, Nembe, Bayelsa State, Nigeria: Implications for Public Health

Abstract

Seafood accumulate contaminants primarily by uptake through the skin and gills, surface contacts with sediments, industrial effluent, wastewater, and food consumed. Health risk assessment is a quantitative and qualitative evaluation of the risk posed to human health by the actual or potential presence of specific pollutants. This study is based on the health risk assessment of heavy metals and polycyclic aromatic hydrocarbons (PAHs) in selected seafood from Okoroba, Bayelsa State, Nigeria. Seafood was collected from Okoroba River. Heavy metals, PAHs, Daily Intake, Life Cancer Risk, Total Life Cancer Risk, Target Hazard Quotient, and Hazard Index of hazardous heavy metals were investigated based on standard methods of estimation. The Ni, Cr, Pb, and Cd level in Calcinuselegans were 29.79±0.01mg/kg, 2.49±0.01, 2.49±0.01mg/kg, 1.19±0.01mg/kg, and 2.19±0.01mg/kg respectively, were significantly higher than the reference values which were 5.5mg/kg, 0.05mg/kg, 0.2mg/kg, and 1.0mg/kg respectively and similar differences were observed in Catharanthus roseus, Oxudercinae, and Sesamumindicum. The estimated daily intake of Ni, Cd, and Pb in Calcinuselegans was 10.032mg/kg, 2.160mg/kg, and 0.301mg/kg respectively, were significantly higher than the reference values 0.5mg/kg, 0.00mg/kg respectively and similar trends occurred in Catharanthus roseus, Sesamum indicum, Gecarcinidae, and Atlantic silverside. The target hazard and hazard index of Ni, Pb, and Cd in Halichoeres bivittatus were 3.600mg/kg, 1.380mg/kg, 6.010mg/kg, and 2.050mg/kg respectively, which were significantly higher than the reference values 1mg/kg and similar trends occurred in Schilbemystus, Bagrus bajad, Atlantic silverside, Portunus armatus, and Catharanthus roseus. The estimated daily intake of Ni, Cd, and Pb in the studied seafood were higher than the Recommended Tolerable Daily Intake levels of heavy metals in sea food. The estimated daily intake, target hazard quotient and hazard index of Ni, and Pb evaluated are suggestive of possible health risks on the indigenous people of Okoroba community upon consumption for period of time.