Bioaccumulation factors for PFAS in Australian environments

Full text: Introduction - The bioaccumulation potential of per- and poly- fluoroalkyl substances (PFAS), particularly PFOS, is a key environmental behaviour to consider when assessing the environmental impacts of these compounds. Given the unique physico-chemical characteristics of these substances, bioaccumulation factors (BAFs) cannot be reliably calculated using theoretical methods applied to other compounds. Rather, empirical data is required to quantify bioaccumulation through the calculation of BAFs such as bioconcentration factors (BCFs), biomagnification factors (BMFs), and biota-sediment/soil accumulation factors (BSAFs). Methods - Using publicly available environmental sampling data a range of BAFs have been calculated for PFAS in Australian environments, for both terrestrial and aquatic settings. Results and discussion - A comparison of calculated values to those published in international studies indicates consistency between the rates of bioaccumulation of PFAS in Australian environments and those reported in the literature. BCFs of approximately 1,000 to 3,000 were calculated for PFOS migrating from surface water into fish from freshwater surface water bodies, which were comparable with the PFOS BCF of 2,800 adopted by several international agencies. Factors calculated for PFOS in marine environments were lower than the freshwater values, with surface water to prawn BCF's of approximately 10 to 60 and surface water to fish BCFs <300. BSAFs for terrestrial environments indicate much lower rates of accumulation of PFOS from soil to grass or plants, with BSAFs generally <1 calculated. Limited data has been published on poultry uptake, however a BSAF from soil to eggs of <1 was calculated from the available data. BAFs for other PFAS and additional scenarios have been calculated where published sampling data was available. Conclusions - The available Australian data indicates that significant variability in bioaccumulation can be observed under different environmental settings. Rates of bioaccumulation were higher in freshwater than marine environments, and were more significant in aquatic than terrestrial environments. These findings were consistent with the available international literature which has reported a similar range of values for the bioaccumulation of PFAS. (author)