Validation of soil leaching protocols for determining PFAS mobility in soils

The use of poly- and perfluoroalkyl substances (PFASs) and their precursors in some firefighting foams has led to contamination of land in Australia and overseas. One concern is that the relatively high water solubility of PFAS results in their ability to be leached from soils and be transported long distances in groundwater. Measurement of leachability of PFASs from soils is therefore important for assessing contaminated sites, but validation information for PFAS leaching protocols is lacking. This study used three contaminated soils from fire training grounds with different concentrations of PFASs. The aim of the study was to assess: the experimental variability amongst PFAS concentrations in leachates using the Australian Standard Leaching Protocol (ASLP) with unbuffered reagent water; the difference between ASLP leachate results based on different soil preparation methods; the effect of leachate storage time, prior to filtering and analysis. Aims 1 and 2 were also investigated using Toxicity Characteristic Leaching Procedure (TCLP) at pH 5. (author)