Assessment of Polycyclic Aromatic Hydrocarbon Contamination of Fruits, Leaves, and Soil within Automobile Repair Workshops in Nsukka Metropolis

Abstract

The level and distribution of Polycyclic Aromatic Hydrocarbon (PAHs) in soil, fruit, and leaf from within automobile repair workshops in Nsukka metropolis was assessed. The PAHs concentrations were evaluated using Gas Chromatography-Mass Spectrophotometer (GC-MS). The health risk was assessed using incremental life cancer risk (ILCR) and mutagenic effect and the possible sources of the PAHs were estimated by the diagnostic ratio. The results showed that the concentrations of the PAHs in soil, fruit, and leaf ranged from 0.003 to 0.564, 0.011 to 0.070, and 0.020 to 0.120 µg/kg, respectively. The mean PAHs concentration for soil, fruit, and leaf are 0.229842, 0.034059, and 0.043091 µg/kg, respectively. The TEQs were generally within the acceptable limit stipulated by Agency for Toxic Substances Disease Registry–ATSDR (100 µg/kg) for non-pollution and low toxicity. The incremental lifetime cancer risk (ILCR) for the seven prominent carcinogenic PAHS indicated that Benzo(a)pyrene and Dibenz(a,h)anthrance, being the most toxic were above the acceptable limit of 1 × 10−4 showing possible carcinogenic effects to humans with children being the most vulnerable. Although the concentration of PAHs in this study is lower than many similar cases, they have a high risk of carcinogenesis. In contrast, the Mutagenic Equivalent Quotient (MEQ) values were generally within the acceptable value. Benzo(a)pyrene and Dibenz(a,h)anthrance were the most contributors signifying possible alternation/modification of DNA in humans. The Diagnostic ratio showed that pyrogenic combustions could be the main sources of PAHs in the studied area. Therefore, it is evident that Nsukka automobile repair area is gradually being contaminated with PAHs.