Polycyclic Aromatic Hydrocarbons (PAHs) in Freshwater Media: Factorial Effects and Human Dietary Exposure Risk Assessment

Polycyclic aromatic hydrocarbons (PAHs) present in water column and preponderant fish species of Anambra River were conducted. Eight PAHs (naphthalene, acenaphthene, fluorine, phenanthrene, anthracene, pyrene, fluoranthene and benzo (a) pyrene) classified as priority pollutants by the United States Environmental Protection Agency and World Health Organisation were measured in the media following solid-phase extraction and gas chromatographic procedures on three factorial experimental model designs. Season was tested at two levels: rainy and dry; fish species at two levels: Synodontisclarias and Tilapia nilotica; and location factor at five levels: Enugu Otu, Ezi-Aguleri, Otuocha, Otu-Nsugbe, and Onono. The human PAH exposure risk was assessed and daily intake through fish consumption determined. Polycyclic aromatic hydrocarbons were found preponderant in the water and fish species for both rainy and dry seasons at the five distinct locations. Concentrations detected in these principal media were generally low compared to earlier studies and unaffected by the season, location and fish species, including all the factorial level interaction effects. However, the dietary intakes of the contaminant through fish consumption were a subject of public health concern on continuous daily exposure as the PAH concentrations in the examined fish sourced from some of the locations in different seasons were higher than stipulated values by Environment Canada for edible tissues of fish and/or shellfish for human consumptions. Effective and continued monitoring of the quality conditions of the river needs to be sustained and compared with baseline catchment data for quality deviation as crude oil production is expected to commence at this delicate site. Further quantifications of these organic substances in other fauna and investigation in entire flora of the river, and modelling of its trophodynamics would practically underpin sound management strategies and sustainability of the aquatic resources.