Use of PIANO Data to Identify Source and Potential Age of Subsurface LNAPL at a Pipeline Terminal.Environmental Forensics
Oral Presentation
Presented by H. Lord
Prepared by H. Lord1, D. Thal2
1 - Environmental Standards Inc., 1140 Valley Forge Road, Pheonixville, Pennsylvania, 19482, United States
2 - Environmental Standards Inc., 8331 E Walker Springs Ln, Knoxville, Tennessee, 37923, United States
Contact Information: [email protected]; 484-460-2210
ABSTRACT
An LNAPL sample was collected from a monitoring well at a pipeline terminal at two timepoints one year apart from each other. A full suite of forensic characterization was performed at year 1. A whole oil analysis conducted on the sample at year 2 showed a high degree of similarity with the year 1 sample so no further investigation was pursued on the second sample.
The initial forensic investigation suggested that the LNAPL was most likely comprised of a combination of both a partially degraded gasoline range hydrocarbon product and an older more highly degraded middle distillate product containing hydrocarbons in the n-C16 to n-C28 range. As the gasoline range component was of primary concern for the investigation further efforts were focused on interpreting the PIANO data. The PIANO profile from the LNAPL best correlated to a reference low-octane gasoline profile, although significant biases were seen in the aromatics and Isoparaffins fractions. These could not be explained by the co-mingled degraded middle distillate product. A detailed investigation of the compositions of the paraffins, isoparaffins and aromatics fractions provided evidence that supported the conclusion that the gasoline range component of the LNAPL was comprised of either multiple discrete gasoline range product releases, or a slow release of a single gasoline range product over an extended period of time.
This presentation will describe the overall investigation processes undertaken and the approach used for the PIANO component investigation to support the conclusion of gasoline range product releases over time rather than a one-time release.
