Per- and poly-fluoroalkyl substances (PFAS) represent a complex mixture of thousands of individual compounds with documented wide-spread legacy impact in the environment. The webinar explored challenges and learnings in assessing human health and ecological risk of PFAS in an urban marine environment with multiple industrial areas as potential PFAS sources. This session presented the results of extensive investigation of PFAS within the Brisbane River system (surface water, sediment and biota). The results highlighted the prevalence of PFAS across all media within the entire spatial extent of the investigation. The results presented include the changes in distribution of PFAS across all media, measured bioaccumulation factors for PFOS in fish, and results of TOPA analysis conducted in all media.
Key lessons learned from the study presented were:
- PFOS was the predominant PFAS compound bioaccumulating in aquatic food chains, likely due to inputs from historical/current urban environments.
- The presence of PFOS from a variety of potential historical/legacy sources in environment presents challenge associated with quantifying site-specific contribution to risk from PFAS measured in the food chain.
- PFOS impact in the environment was widespread
- PFOS clear driver for risk for all receptors and locations
- Toxicity for compounds other than PFOS is a key sensitivity/uncertainty. In this assessment PFOS was still the key risk driver even when using PFOS / PFOA as surrogates.
- Understanding of the site-source and consideration of overall mass was a key for the site-specific assessment.
- Indicated that the percent of “unknown” PFAS reduced as the investigation moved away from sources areas through surface water pathways and into biota.
- Provided a line of evidence for identifying areas of PFAS impact with different sources.
- Limitations in using TOPA include cost, longer turnaround times that caused project delays, and challenges in the quality control review of TOPA results across multiple matrices.
- Conducting TOPA on every sample was not necessary for the study and if conducting TOPA it is worthwhile to focus on key focus areas for risk assessment or remediation deceision-making.
- Biota Sampling
- Very challenging (time and costs) to get data from target species.
- Results from the adjacent marine environment with multiple PFAS sources does not provide clear understanding of site-related risks.
The results of this investigation represent a single data set for marine environment, however this data adds to the growing data set and reduces the uncertainty associated with using BAFs to estimate PFAS concentrations in aquatic biota.
Ken Kiefer is a Technical Director and the Global Risk Assessment Technical Community leader at ERM. Ken has over 20 years of experience in the human health and ecological risk assessments for complex sites with multiple regulatory stakeholders in the U.S. and Australia.
Ken has conducted PFAS risk assessments for a variety of Defence, Oil and Gas, and Aviation sites over the last 6 years in Australia. He can be contacted here.