PAH concentrations in sediment from Jones Creek Delta State, Nigeria: distribution and lifetime cancer risks

Abstract

Concentrations of the sixteen USEPA and Water Framework Directive (2006/60/EC) priority pollutants - polycyclic aromatic hydrocarbons (PAHs) in sediment and shrimp samples in Jones Creek southern Nigeria was investigated from March 2015 to August 2016. The ΣPAHs ranged from 0.32±0.07 to 48.38± 2.47 mg/kg for sediment samples collected for the 18month duration of this study. The PAH concentrations obtained in the sediment suggest the dominance of the high molecular weight pollutants (benzo[a]anthracene) indicative of a pyrolytic source. Assessment of the cancer potential risk using the Increased Lifetime Cancer Risk (ILCR) indicated a high exposure potential for the sampling location. Several of them are known carcinogens including benzo[a]anthracene, chrysene, benzo[b]fluoranthene, benzo[a]pyrene and benzo[g,h.i]perylene. Diagnostic ratios such as phenanthrene/anthracene and fluoranthene/pyrene were employed to evaluate the emission sources of PAHs. These ratios indicated a pyrolytic source of PAHs for sediments obtained within the study area.

Keywords: PAHs, sediment, cancer risk, diagnostic ratio, ILCR