Forensic source attribution for toluene in environmental samples

The formation of toluene by microbiological processes can confound environmental investigations relating to petroleum releases. This is because toluene is a constituent of petroleum and can move readily within wetland environments, and analysis for toluene in relation to a petroleum release can lead to incorrect assignment of detected biogenic toluene as related to the release. No legally defensible method of distinguishing biogenic and petrogenic origins of detectible concentrations of toluene have been demonstrated to date. Using example petrogenic samples and samples of peat from 2 wetland environments, a poor bog and a poor fen, the present study demonstrates the use of an established ASTM International analytical methodology that was originally designed for arson analysis for the determination of the origin of toluene. Environmental forensic data-interpretation methods such as chromatogram inspection and diagnostic ratios are shown to be capable of readily distinguishing biogenic and petrogenic origins of toluene. Environ Toxicol Chem 2018;37:729-737. © 2017 SETAC.