In 2018, the Department of Environment and Science (DES) undertook a number of investigations relating to per- and poly-fluoroalkyl substance (PFAS) contamination. As part of these investigations, quality control samples were collected. Results from duplicate samples sent to different laboratories identified significant variability between laboratories. To investigate this variability, and to determine whether it might be due to laboratory processes or sampling processes, a blind inter-laboratory testing program was undertaken on spiked water samples and homogenous environmental samples of water, soil and biosolids.
Results from the analysis of spiked solutions of water showed that there was under-estimation of PFAS concentrations, with all the laboratories reporting PFAS compounds at less than the spiked concentrations. Also, all laboratories reported reduced concentrations as the chain length of the PFAS increased. The results from this study indicate that Australian laboratories are routinely underestimating PFAS concentrations in environmental water samples. Results from homogenous environmental samples indicated a large variation between laboratories.
The results from this study reveal limitations in the analysis of PFAS in waters, soils, and biosolids that could impact the assessment and management of PFAS. PFAS analysis is complicated and is evolving. The study highlights the need for a clear and concise way forward for assessing data with respect to analytical uncertainty calculations, and the need for national guidance on taking uncertainty into account where assessment against guidelines forms part of a risk assessment. In addition, transparent communication around improvements in the PFAS analytical methods is needed in order for any changes in PFAS concentrations over time to be assessed – i.e. are changes over time real or due to improvements in analytical methods?