Distribution Pattern and Potential Ecological Risks of PAHs in Soils in the Vicinities of Open Dumpsite in Yenagoa, Bayelsa, Nigeria

Abstract

The concentrations, distributions, and associated risks of polycyclic aromatic hydrocarbons (PAHs) in soils of dumpsite and its vicinities  were investigated. Composite samples were taken from the dumpsite and distances (15, 30, 60, 90, 120m) away from the foot of the  dumpsite; as well as from a control site (2000m away). The determinations of PAHs were done with gas chromatography couple to mass spectrometer (GC-MS) after extractions with dichloromethane (DCM) and a silica gel clean-up. Total PAHs (Σ16PAHs) concentrations in the  dumpsite soil and that of the control were 930.05, and 31.15 µg/kg respectively. Values of 238.57, 118.39, 75.56, 58.24, and 47.61µg/kg  were obtained for the distances of 15, 30, 60, 90, and 120m away from the foot of the dumpsite respectively. Ecological risk assessment, implicated the dumpsite’s soil to be of moderate pollution, while at distances of about 15m away from the dump, the effects  seem negligible. The human toxicities assessment reveals that the concentrations of PAHs in soils of the dumpsites and its vicinities were  still within safe limit. However, due to possible accumulations of PAHs in soils, it is recommended that appropriate measures be taken to  regulate the management of wastes in the city of Yenagoa.