Polycyclic Aromatic Hydrocarbons in Ado-Ekiti Roadside Soil, Nigeria: Distribution, Source Identification, Composition Profiles, and Toxic Potential

Abstract

The study considered the level, origin with toxic potentials of PAHs in soil roadside of Ado-Ekiti, Nigeria. Gas chromatographic technique was employed for the identification of PAHs after extraction and silica gel cleanup. Average concentration of the PAHs ranged from ND – 51.6 ± 46.7µg/kg, while total polycyclic aromatic hydrocarbons (TPAHs) ranged of 61.8±32.3 - 204±28.0 µg/kg with contamination pattern of ADY ? AJI ? EKSU ? NNPC. The percentage distribution of LMW ranged from 17.3 – 54.2%, while the HMW-PAHs showed 46.0 - 82.7%. The PAHs pattern was dominated majorly by 5- and 6- ring with distribution range of 15.1 and 43.2%. The overall diagnostic ratios of the soils suggested pyrogenic, coal/wood/grass/vehicular combustion in most cases. To evaluate the toxicity of the PAHs in the samples, PAHs toxic equivalence factors (TEFs) revealed that carcinogenic PAHs contributed majorly (over 95%) to toxicity of the soil.