PFOS bioaccumulation in aquatic biota & Emerging contaminants and emerging issues using cluster analysis

Title: Exploring the data – can we explain the variability in PFOS bioaccumulation in aquatic biota?

Authors: Janina Beyer & Karl Bowles

Abstract:

Perfluoroalkyl acids (PFAAs) are a group of chemicals that are known to bioaccumulate, but by a different mechanism to other persistent organic pollutants such as chlorinated pesticides. In particular, perfluorooctane sulfonate (PFOS) has been shown to bioaccumulate in biota, but apparently due to protein affinity, rather than lipophilicity. While PFOS bioaccumulates and biomagnifies in terrestrial organisms, PFOS bioaccumulates (to a significant extent) but does not appear to biomagnify in aquatic organisms, presumably due to the depuration of PFOS via the gills (Kelly et al, 2009). This is consistent with reported concentrations in invertebrates and fish, where no clear patterns in PFAS concentrations and trophic structure are apparent (e.g. Taylor et al, 2018). We have previously discussed the limitations of using bioaccumulation factors (BAF) for PFOS, questioning the use of BAFs in a predictive way (Bowles, 2018; WIOW presentation). The limitations of using BAFs for PFOS are also described in Franklin (2016).

This presentation seeks to identify and summarise the key factors which may be contributing to the large variation in BAFs in aquatic biota. We do this by reviewing data from a range of PFAS studies, as well as exploring PFAS measurements in aquatic biota from field studies related to PFAS contaminated site assessments. A focus in this presentation is how PFOS bioaccumulation differs between different environments (freshwater, estuarine and marine) and the potential key mechanisms which appear to contribute to the high variability in BAFs between species. This will touch on some of the key mechanisms expected to contribute to the bioaccumulation of PFOS in aquatic species, including direct exposure to sediment/water, food uptake/trophic transfer and insights into rates of depuration.

Overall, this work is based on exploring existing data to conceptualise the key mechanisms contributing to PFOS uptake in aquatic biota, and how this is important for the development of guidelines for assessing ecosystem harm.

Title: Thinking outside the box - exploring how to capture emerging contaminants and emerging issues using cluster analysis.

Authors: Janina Beyer¹, Mega Ng¹, Minna Saaristo² and ³Suzanne Vardy. NSW Department of Planning, Industry and Environment (DPIE), Science, Economics & Insights Division, Sydney, Australia, ²EPA Victoria, Water Sciences, Melbourne, Australia, ³QLD Department of Environment and Science, Water Quality and Investigations, Brisbane, Australia

Abstract: Emerging contaminants are chemicals that are characterised by a lack of published (eco)toxicity data and/or lack adequate analytical methods to quantify the chemicals in environmental samples for their potential harm. Prioritising chemicals of concern has been mainly done using existing hazard and exposure data and this process has been based on chemical and (eco)toxicity data gathered from literature or international databases (e.g. ECHA), as well as on exposure data (e.g. volume or monitoring data) to assess potential risks. Paradigms, such as the PBT (Persistent, Bioaccumulative, Toxic) paradigm have been widely used in identifying key chemical properties that contribute to emerging contaminants, particularly for organic contaminants. This paradigm works when we have enough information for a given chemical, and where persistence, bioaccumulation and toxicity are the key drivers for an emerging contaminant. Whilst PBT information is important, focusing just on these properties overlooks chemicals which have gaps in the data, and situations where multiple chemicals contribute to an emerging issue or chemical mixtures. 

This paper proposes a cluster analysis model for assessing contaminants, rather than ranking chemicals. Using subsets of organic and inorganic chemicals, we include different types of data beyond PBT that are not conventionally used in chemical prioritisation into our model. Specifically, this method will a) consider the data gaps that exist for many chemicals (e.g. consider incorporating non-traditional ecotoxicity methods such as behavioural data), b) incorporate how chemicals contribute to emerging chemical issues (e.g. antimicrobial resistance), and c) consider the pathway in which a contaminant enters the environment.  This enables us to identify and manage sensitive pathways which could contribute to emerging issues in the future. This model provides an important alternative way of considering emerging contaminants and contaminant issues beyond the PBT paradigm.

Janina Beyer is a Principal Project Officer in the NSW Department of Planning and Environment, Science Economic and Insights Division. Her background is in environmental monitoring and risk assessment of contaminants, having worked in research, consulting, and government. Janina’s key skills are investigating the potential human health and ecological risks from contaminants in the environment. Key contributions have been in assessing contaminants in waste, water quality monitoring, ecological monitoring, and using this science to inform policy and regulatory decisions in government. Since 2015, her work has been on per- and poly-fluoroalkyl substances (PFAS), with significant contributions on assessing PFAS contaminated sites in NSW and technical input for policy decisions. More recently, in her role in the NSW Government, Janina has been focusing on chemical prioritisation and assessing potential risks of emerging contaminants in a circular economy context.