Concentrations, Origin, and Associated Exposure Risk of Polycyclic Aromatic Hydrocarbons in Soil Depths from Selected Petroleum Tank Farms in Western Delta, Nigeria

Abstract

This study determined the background occurrence, distribution, and exposure risks of the sixteen priority polycyclic aromatic hydrocarbons (16-PAHs) in soils from the vicinity of petroleum tank farms in Western Delta, Nigeria. The samples were collected in the fifteen petroleum tank farms at 0–15 cm, 15–30 cm, and 30–45 cm depths. After extraction by ultrasonication with n-hexane/dichloromethane and clean-up in silica gel/alumina packed column. The concentration of PAHs was determined using gas chromatography fitted with mass spectrometry (GC–MS). The Σ16-PAHs ranged from 4.49 to 447.86 mg kg-1 for all sites and depths. The concentration of the Σ16-PAHs in the samples exceeded the Department of Petroleum Resources (DPR) target values, and 38% depicts PAHs concentrations above the DPR intervention values, this suggests the presence of high molecular weight petroleum products such as diesel and heavy oil, and soils from the tank farms' are polluted with a considerable amount of soils within PAHs. The total cancer risk falls within the low to moderate category. The principal sources of PAHs are petrogenic and low-high-temperature combustion processes. This study provided empirical data on the pollution load, origin, and associated risks of PAHs in soils in some petroleum tank farms. Appropriate clean-up actions are needed to mitigate the accumulation of PAHs in soil and biota and the ecological and human exposure risks in the surrounding aquatic and terrestrial environments. Supplemental data for this article is available online at online