SOT Spotlight: Q&A with Melinda Donnell

Posted on Behalf of  Melinda Donnell

What is the title of your presentation?

Using E-FAST Platform to Predict Human Exposure to 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 in 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. The current study explored a modeling approach that could be used to evaluate human exposure to newer and less studied PFAS. This study focused on perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS), since these are the two most commonly studied PFAS, facilitating validation of the approach. Specifically, the Exposure and Fate Assessment Screening Tool (E-FAST) was used to estimate exposure to PFOA and PFOS via ingesting drinking water and consuming fish following a discharge from several wastewater treatment facilities (WWTPs). The predicted potential lifetime average daily dose (LADDPOT) values for consuming PFOA/PFOS-containing fish/drinking water were compared to LADDPOT values calculated based on reported data.

What did you find?

We found that PFOA had lower predicted and calculated LADDPOT values than PFOS, indicating lower exposure. Further, higher predicted and calculated LADDPOT values for fish and drinking water were noted for WWTPs discharging into the marine environment. Moreover, the calculated LADDPOT values for drinking water and fish were within the range of predicted LADDPOT values for PFOA and PFOS; however, there was limited information regarding PFOA and PFOS concentrations in fish associated with the sites of interest. We concluded that the outlined approach could be a useful tool for estimating the potential human exposure associated with PFAS release with limited toxicological information from WWTPs.    

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 and subsequent contamination of drinking water and bioaccumulation in fish are of 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.