Evaluation of the contamination of the subsurface and groundwater by monoaromatic hydrocarbons in an eastern Amazonian town in northern Brazil

Abstract The present study evaluated the contamination by monoaromatic hydrocarbons (BTEX: benzene, toluene, ethylbenzene, and xylene) of subsurface gas stations adjacent residences in Amazonian town Bragança, northern Brazil. We combined ground penetrating radar (GPR) geophysical tool, to detect possible plumes BTEX, with chromatography (GC) mass spectrometry (MS), which were used diagnose presence BTEX water samples obtained from boreholes located within area. GPR identified low-amplitude reflections vadose zone two stations, whose attenuation near surface was due low permittivity recorded radargrams, may have been caused reduced (gas vapor) comparison water. GC–MS ethylbenzene and/or xylene 13 (19.7% collected). Only three contained contaminants, invariably toluene xylene, whereas all others only a single BTEX. Toluene compounds found most frequently samples. However, none collected exceeded threshold established Brazilian legislation for BTEXs drinking integrated application CG-MS produced satisfactory results diagnosis surveyed study.