Assessment and fate of PFASs in soils

Associate Professor Christopher Higgins, an environmental chemist from Colorado School of Mines, gave a thought provoking seminar entitled ‘Poly- and Perfluoroalkyl Substances (PFASs) in Soils - Assessment and Fate’ at UNSW Sydney on 5 March.

 A/Prof Higgins is a world-leading expert on grappling with the challenges posed by the widespread PFAS contamination of soils and groundwater.  In Australia, PFAS has received considerable media attention (including numerous front page news articles and an ABC Four Corners episode which aired in October 2017) due to subsurface contamination emanating from a number of military installations including Williamtown, Oakey, Tindal and fire training areas such as Fiskville.

A/Prof Higgins’ research group is current focusing on PFAS contaminants derived from aqueous film-forming foams (AFFFs), which to date have garnered little attention.  He is using high resolution mass spectrometry (HRMS) to detect dozens, if not hundreds, of additional PFASs that may be associated with AFFF-impacted sites. While these other PFASs are likely present in AFFF-impacted drinking water, their presence and role in soils remains poorly understood.

Importantly, many of these newly discovered PFASs have diverse chemical structures, including anionic, cationic, and zwitterionic moieties. A/Prof Higgins' talk provided an excellent detailed discussion of the complexity of the challenges posed by the composition as well as the unique behaviors of PFASs.

Collectively, these data point to a need for a more comprehensive characterisation of PFASs present in AFFF-impacted soils that may serve as long-term sources of PFAAs to groundwater. A/Prof Higgins’ seminar is part of UNSW’s ongoing strategic area of interest in emerging water contaminants.