PFAS compounds have exceptional interfacial properties and, as such, they have been widely used since the 1960s for a range of applications, including in aqueous film forming foam (AFFF). These foams are designed to be naturally resistant to degradation meaning that they have a very high environmental persistence. Their unique properties mean that each individual PFAS compound may impact insitu microbial communities to differing extents or may be degraded by insitu microbial communities to differing extents, if at all. Furthermore, PFAS may have unexpected impacts on specific microbial functional groups (aerobic heterotrophic bacteria, nitrate reducing bacteria, sulphate reducing bacteria, iron reducing bacteria, organohalide respiring bacteria, methanogenic archaea) and that these effects may prove diagnostic for PFAS impacted areas. Given their unique chemical structures PFAS are highly surface active further complicating an assessment of their environmental fate and impact to insitu microbial communities. In this study we collected over 80 water samples from a PFAS impacted site in Canada. Using these samples we conducted an in depth assessment of the impact of PFAS to insitu microbial communities. Specifically, insitu microbial communities were characterized using next generation sequencing to obtain the entire microbiological profile of microbes in sampled aquifers. Data is analysed in conjunction with available site data (e.g., subsurface stratigraphy), monitoring well data (e.g., pH, ORP, inorganic species) and soil data (e.g., soil type, organic carbon). This data provides important insights into these interactions. Although PFAS constituents did not impact community structure the relative abundance of a number of individual genera were significantly associated with PFAS chemistry. For example lineages within the Oxalobacteraceae family (some classified within the Janthinobacterium genus) have the strongest correlations with PFAS chemicals. Out of all the significant correlations between microbial lineages and firefighting foam chemistry, Oxalobacteraceae have the strongest correlation with total PFAS and components PFBS, PFHpA, PFHxS and PFOA. Additional correlations, their possible causes and implications will be discussed.

Interrelationships between PFAS and in situ microbial communities at an AFFF field site

2019 Spring National Meeting

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