Characterization of a Suspected Hydrocarbon Contaminated Site Near Mamanguape (Paraiba, Brazil) Using Integrated Geophysical and Geochemical Methods

A dark stain was detected by chance on a bank of the B-101 highway from Natal to João de Pessoa near Mamanguape (Paraíba State, Brazil). A detailed visual examination suggested that the stain might be a hydrocarbon pollution plume resulting from an unintentional or furtive spill (Fig. 1). Some organic pollutants such as polycyclic aromatic hydrocarbons PAHs) are considered carcinogenic (Warshawsky, 1999) and therefore their occurrence on the soil surface and their migration to underlying aquifers constitutes a serious environmental concern and a risk to public health. Because of the gravity of this environmental problem it is crucial to identify the approximate boundaries of a contaminant plume, examine its constituents, identify its origin and evaluate the environmental hazard it represents in order to plan remedial actions (Menzie et al, 1992). The goal of this study was to assess the geometry and extension of the contaminated zone, as well as to characterize the composition and concentration levels of the pollutants. To this end, an integrated geophysical and geochemical study was conducted of the site. The toxicity, extension and characteristics of the pollutant must be considered when planning the most suitable remedial action, which may involve excavation and safe disposal in a specific landfill, “in situ” treatments using microbial or electrochemical degradation, or any other specific clean-up program.