Blog

What is the title of your presentation?

Using ECOSAR and E-FAST Platforms to Predict Ecological Risks of PFAS.

What was the scope of your research?

Per- and polyfluoroalkyl substances (PFAS) are ubiquitous in the environment. PFAS do not readily degrade in the environment, may bioaccumulate through the food web, and have the potential to cause adverse health effects to humans and wildlife. Unlike other persistent chemicals, these chemicals are highly soluble in water and tend to partition to surface and groundwater rather than soil and sediment. Numerous scientific studies from the last 10 years have shown that PFAS exposure can lead to adverse ecological impacts. Consequently, the current study used a modeling approach to evaluate the aquatic toxicity of PFAS, using perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) as examples. The predictive Ecological Structural Activity Relationships (ECOSAR) Class Program was used to estimate PFOA and PFOS aquatic toxicity.. Subsequently, the Exposure and Fate Assessment Screening Tool (E-FAST) was used to obtain estimated environmental concentrations (EECs) in surface water. Risk quotients were derived for PFOA and PFOS based on the gathered information. The results were compared to toxicity thresholds and water concentrations reported in the literature.

What did you find?

We found that PFOA had lower predicted toxicity thresholds than PFOS; however, based on the reported values, PFOA was less toxic than PFOS for some species. Further, aquatic organisms differed in sensitivity to PFOA and PFOS based on predicted and reported data. Moreover, higher EECs were predicted for WWTPs discharging into marine environment compared to freshwater environment; however, the reported EECs were similar. We concluded that some overlap existed between the predicted and reported toxicity thresholds and EECs, providing support that the outlined approach could be a useful tool for estimating the potential release of PFAS (and potentially other chemicals) from WWTPs, and for predicting the potential ecotoxicological implications of such release.   

What are the next steps/what other research is needed?

The next step is to submit for publication the manuscript describing this framework. We think that this framework would benefit industry, since PFAS release via WWTP effluent is an increasing concern. This research is especially relevant for California, since the California State Water Resources Control Board (State Water Board) recently released an investigative order (WQ 2020-00150-DWQ) requiring PFAS sampling and analysis at publicly owned treatment works (POTWs) in California that have a design capacity at or exceeding one million gallons of wastewater per day. The State Water Board determined that 259 POTWs throughout California were subject to this order (for more details please see https://www.cardnochemrisk.com/blogs/blog/california-seeks-action-to-better-understand-pfas-discharge-in-publicly-owned-treatment-works/. Additionally, although the study focused on PFAS, the outlined framework could also be applied to other chemical classes.