The History of Hydrocarbon Analyses: Whence Has Forensic Geochemical Hydrocarbon Fingerprinting Come

The current techniques used in forensic geochemical hydrocarbon fingerprinting have their genesis along with the evolution of gas chromatography as it applies to hydrocarbon research. In the United States, a small group of government and academic chemists and marine scientists pioneered the use of gas chromatography in the identification of both natural and petroleum-derived hydrocarbons. Natural products were a primary focus until the research direction was altered somewhat by marine oil spills, accidents releasing crude oil and refined petroleum products to the world’s coastal marine environment, giving rise to concerns regarding biogeochemical impacts. Application of oil spill research continued from that point so that the geochemical research begun in the late 1960s and early 1970s now forms a major component of investigations of petroleum releases both in the aquatic and terrestrial environments. As the capabilities for the identification of individual hydrocarbons in a variety of petroleum products improved with basic advances in chromatographic technology, new applied sciences in forensic geochemical hydrocarbon fingerprinting have emerged. While in the beginning the identification of bulk petroleum products received primary emphasis, current techniques are now capable of distinguishing among a variety of potential sources including those derived from natural processes, undetected individual releases, chronic releases and obvious catastrophic releases. However, a review of the techniques employed in the late 1960s and early 1970s will show that the basic approaches pioneered at that time are still in use today, albeit with a higher level, with concomitant advances in chromatographic technology as the questions grow in complexity.

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

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.