Spatio-temporal distribution, source apportionment, ecological and human health risks assessment of polycyclic aromatic hydrocarbons in Sombreiro River Estuary, Niger Delta, Nigeria.

Abstract

The spatio-temporal distribution, source apportionment, and risks of polycyclic aromatic hydrocarbon (PAHs) were investigated in the Sombreiro River Estuary, Niger Delta, Nigeria. Water, sediment and oysters were obtained from the estuary and analyzed for 16 priority PAHs using gas chromatograph coupled with mass selective detector after extraction. The levels of the ∑16-PAHs in the water, sediment and oyster ranged from 25-10079 µg/L, 495-12811 µg/kg and 489-10823 µg/kg respectively for all locations and seasons. The results showed significant spatio-temporal variations in PAHs concentrations in all the matrices. The ecological risk assessment revealed high risk posed by the PAHs level to the estuarine ecosystem. The health risk indicated unacceptable carcinogenic risk to human via ingestion of oysters. Besides, for water and sediments, both ingestion and dermal pathways indicated unacceptable cancer risk. Source apportionment suggested that the PAHs in the estuary were from both pyrogenic and petrogenic sources.   .