Evaluation of the topsoil quality for polycyclic aromatic hydrocarbons near automobile repair facilities in Eleme, Rivers State, Nigeria

Abstract

The activities of automobile repair workshops may have a negative impact on the immediate environment due to the kind of waste that is constantly generated and disposed of around these areas. With a view to ascertaining their possible impact on the surrounding soils, top soil samples were therefore collected from selected automobile repair shops in Eleme. The processed composite soil samples were analysed for their polycyclic aromatic hydrocarbon (PAH) content following standard analytical procedures. Results from the impacted sites as well as the control site revealed that PAHs were detected at these stations at varying concentrations in all of the topsoil sampled, following the order: Station 3 > Station 1 > Station 2. There was a considerable difference between the concentration of PAHs in the soil from the automobile repair shops and the control site. The total concentration (mg/kg) of the 16 US EPA PAHs in the soil samples ranged from 34.729 to 35.647, with a mean value of 35.305±1.561, which was markedly higher than the 2.116±0.185 concentration found in the control sample. Source identification and diagnostic ratios of polycyclic aromatic hydrocarbons in the soils revealed that the increased ratio of pyrogenic or combustion-based PAHs found in soil samples from different automobile repair stations is an indication that anthropogenic sources, especially combustion and spills of petroleum products, were the main sources of PAH component input. Therefore, the control of oil spills and automobile use of spent oils should be checked by providing central storage tanks that could be recycled for other purposes.