Spatio-temporal distribution of polycyclic aromatic hydrocarbons (PAHs) in soils in the vicinity of a petrochemical plant in Cape Town

Abstract

Polycyclic aromatic hydrocarbons (PAHs) are an alarming group of organic substances for humans and environmental organisms due to their ubiquitous presence, toxicity, and carcinogenicity. They are semi-volatile substances which result from the fusion of carbon and hydrogen atoms and constitute a large group of compounds containing two to several aromatic rings in their molecule. Natural processes and several anthropogenic activities involving complete or incomplete combustion of organic substances such as coal, fossil fuel, tobacco and other thermal processes, generally result in the release of the PAHs into the environment. However, the fate of the PAHs is of great environmental concern due to their tendency to accumulate and their persistence in different environmental matrices and their toxicity. Animal studies have revealed that an excessive exposure to PAHs can be harmful. Evidence of their carcinogenic, mutagenic, and immune-suppressive effects has been reported in the literature. In the soil environment, they have the tendency to be absorbed by plants grown on soil being contaminated by the PAHs. It is, therefore, important to evaluate their occurrence levels in different environmental matrices such as soil concentrations.