Environmental Forensic Investigation in the Residential Neighborhood Volta Grande IV, Volta Redonda, RJ, Brazil, Using TPH and PAHs Analyses in Soil Samples

摘要

This article presents the results of a forensic investigation concerning the origin of hydrocarbons detected in the subsurface soil of the residential neighborhood Volta Grande IV, Volta Redonda, RJ, Brazil. Previous investigations identified several areas with concentrations of volatile organic compounds (VOCs) and polycyclic aromatic hydrocarbons (PAHs) above the Brazilian regulatory standards of CONAMA 420/2009 within the study area. Concern was raised that these hydrocarbons might be derived from local steel mill wastes. This forensic investigation determined that the VOCs in the residential soil are associated with gasoline and possibly diesel fuel oil releases into the subsurface soils that are not associated with the steel mill waste. The PAHs in residential subsurface soil generally fell below background concentrations and are likely associated with regional soot. The PAHs in the three samples with concentrations above background (out of a total of thirty-six samples) exhibit compositional features similar to coal byproducts, such as tar and coke, possibly attributable to the steel mill operation. This work discusses the geoforensic data and chemical signatures that support these findings.