Using ECOSAR and E-FAST platforms to predict ecological risks of PFAS from semiconductor facilities
Andrey Massarsky, Jordan S. Kozal, and Andrew D. Monnot
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 effects to the health of 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 in the environment. The current study explores a modeling approach that could be used to evaluate ecotoxicity of the newer and less studied PFAS, thereby reducing the need for animal testing. This study focuses on perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS), since these are the two most commonly studied PFAS, facilitating validation of the proposed approach. In the first step, the Ecological Structural Activity Relationships (ECOSAR) was used to derive acute and chronic toxicity threshold values for PFOA and PFOS for several aquatic species, including fish, Daphnid, mysid, and green algae. In the second step, the Exposure and Fate Assessment Screening Tool (E-FAST) was used to derive the surface water concentrations for PFOA and PFOS following a discharge from facilities where semiconductor materials were produced and/or used (which discharged into rivers or ocean), using a wide range of hypothetical industrial release scenarios (0.001-10 kg PFOA or PFOS per site per day). In the third step, risk assessment was conducted by calculating the acute and chronic risk quotients (RQs). The acute and chronic RQs for PFOA and PFOS were determined for various aquatic organisms (e.g. fish, Daphnid, mysid, and green algae) for each facility and industrial release scenario. The results of these risk assessments can be used to inform on whether the discharge of or release of PFOA and PFOS from certain semiconductor facilities could pose an ecological risk. Further, the outlined approach will serve as a useful tool to predict the ecotoxicity of newer and less studied PFAS and potentially other chemicals with limited ecotoxicological information.