Petroleum released into the environment is subjected to numerous biotic and abiotic processes. Monitoring the losses caused by these varying processes is important in order to reliably assess the effectiveness of natural attenuation versus remediation techniques. Traditional methods of characterising and monitoring oil from spills generate either a gross measurement or a very specific measurement of petroleum components. The latroscan thin layer chromatography (TLC) flame ionization detection (FID) system represents an analysis that performs quantitative gross compositional analysis of oil samples. The latroscan TLC/FID system measures the relative percentages of the four major fractions of petroleum; saturate, aromatic, resin, and asphaltene. Measurement of these petroleum fractions over time allows for the evaluation of compositional changes due to weathering and degradation processes. The objective of this study was to demonstrate the effectiveness of the TLC/FID system as a tool to monitor changes in petroleum composition from environmental processes. Results of the experiment showed an initial rapid decrease in the compositional saturate and aromatic fractions coinciding with an increase in the resin fraction. The asphaltene content remained relatively constant throughout the project.