Investigation of some Persistent Organic Pollutants in Soil around selected Auto-Mechanic Workshops in Osogbo

Public health is at risk due to pollution from activity in car workshops as the quality of the soil near auto businesses has received less attention. This study assessed soil quality in auto shops in Osogbo, Osun State, South-West Nigeria. Two car workshops were chosen and soil samples were collected from two different points each using a random survey method (i.e., picked two sites randomly). The soil samples were collected at irregular positions within the vicinity of the two auto repair shops at 0–20 cm and 20–40 cm depth. The samples were taken for examination of polychlorinated biphenyls (PCBs) and (Polycyclic aromatic hydrocarbons) PAHs. The samples were analysed in the lab according to regular technique, and 16 US EPA priority PAHs and PCBs were then examined using a gas chromatography-mass spectrometer (GC-MS). The potential toxicities were evaluated and values obtained were compared with United States permissible limits for soil quality. The total PAH values in the soil were between 0.17 μg/m3 to 4.97 μg/m3, with the soil samples near the truck maintenance shops having the greatest PAH concentrations between 0 – 20 cm below the surface. The most prevalent PAH species in soil samples was Fluoranthene, followed by Fluorene and Indeno [1,2,3-cd] pyrene. Also, PCBs were found in the location with 1,1′-Biphenyl, 2,2′,3,4,4′,5′-hexachloro- (PCB 138) having the highest concentration value followed by 1,1′-Biphenyl, 3,3′,4,4′-tetrachloro- (PCB 77). The findings of this study showed that both of these pollutants investigated are very prevalent in these areas. There is a grave environmental concern because the discovered levels of PCBs and PAHs exceed the permissible limits set by the USEPA standards.