Recent work at the Guadalupe Oil Field in Central California has resulted in the application of analytical techniques designed to separate “dissolved” organic matter found in aquatic environments into aliphatic, aromatic, and polar fractions. The significance of understanding the chemical nature of “contaminants” in surface and groundwater environments is critical to understanding and managing potential risks associated with impacted environments.

Initial findings from this ongoing study indicate that the polar fraction may account for a significant amount (up to 100%) of the operationally-defined Total Petroleum Hydrocarbons (TPH) measured in these environmental aquatic media using standard EPA analytical protocols. Of specific interest are the potential sources of compounds that define the polar fraction and the effect of environmental fate and transport processes on the aliphatic, aromatic, and polar fractions. Recent analyses of crude oil and refined products indicates that polar compounds are present at relatively low levels in these “fresh” sources. Other potential sources include in situ biogenically produced material associated with microbially-mediated processes. These findings will be discussed in the context of current risk management paradigms as well as in terms of the potential implications for a more realistic understanding of the complex interplay between the contaminants and the environment.