Assessment of PAHS and the N-PAH Analogues in River Sediment Cores From Niger Delta
Chemical surveys of sediment core samples are major sources of historical pollution trends in aquatic environment. Vertical profiles of PAHs and N-PAHs for the 2 cm, from sediment cores samples (0–10 cm) obtained from Bonny Estuary, in the Niger Delta region of Nigeria, were assessed. The PAHs and N-PAHsfound in the core samples appeared to be from both petrogenic and pyrogenic sources.Petrogenic-PAHs/N-PAHs resulting from oil spills were predominated by 2-, 3-ring and alkylated-substituents, while pyrogenic-PAHs/N-PAHs from industrial activities were dominated by 4-, 5-, 6-rings. Further, ƩPAHs ranged from 66943.95 µg/kg - 84623.81 µg/kg, while ƩN-PAHs ranged from 2841.53 µg/kg - 7156.49 µg/kg. Surface sediment contamination was dominated by petrogenic-PAHs/N-PAHs, while deeper sediments were heavily contaminated with pyrogenic-PAHs/N-PAHs. Assessment with the sediment quality guidelines (SQGs) suggeststhat the core segments are ‘heavily contaminated’ and ‘toxic’. Surveys, such as this, may be helpful in the future sediment-management-decisions for contaminated systems and long-term-monitoring of surface sediments to assess recovery.
Keywords- PAHs, N-PAHs, petrogenic, pyrogenic, sediment.