John Stults
PhD Candidate
Colorado School of Mines
I am a current PhD candidate at the Colorado School of Mines working with the Strategic Environmental Research and Development Program. This is a joint venture by the Department of Defense, the Department of Energy, and the Environmental Protection Agency to study the factors which affect the fate and transport of PFASs in saturated and unsaturated groundwater systems.
PRESENTATION TITLE
Development of a Quasi-Saturated Column Method for Measuring the Multi Phase Partitioning of PFASs Absent Non-Fickian Transport Effects
Per- and polyfluoroalkyl substances (PFASs) are highly mobile, persistent, and toxic chemicals which are known to adsorb to air water interfaces, non aqueous phase liquid (NAPL) interfaces, and solid grains in unsaturated soil systems in the subsurface. The estimation of parameters that characterize the partitioning behavior is important in model predictions of the fate and transport. Currently, there is debate over the appropriate isotherm for modelling the air-water interfacial partitioning of PFASs. Different methodologies have been developed to measure air-water interfacial partitioning which either support a Freundlich type (non-linear) isotherm below a critical reference concentration (CRC), or Langmuir type (linear) isotherm below a CRC. The methodologies which support a Langmuir type isotherm suffer from significant methodological flaws. Specifically, traditional column transport methods which support a Langmuir isotherm suffer from understudied non-Fickian transport effects. A quasi-saturated column method is developed to measure multi-phase PFAS partitioning absent non-Fickian transport effects