Model-Based Assessment of Groundwater Contamination with PFOS due to Fire-Training Activities

Aqueous film-forming foams (AFFFs) containing perfluoro-octane sulfonate (PFOS) were commonly used in fire trainings until the awareness of their toxicity started to increase in the 2000s. Our objective was to build a modeling framework for estimating groundwater pollution with PFOS, utilizing dual-permeability modeling still novel for groundwater studies. The framework was applied to an existing contamination site. According to the results, only 27% of PFOS released from the fire-training area reached the aquifer. Adsorption to unburnt fuels and removal via oil separation wells before discharging to the aquifer can substantially reduce the PFOS contamination of groundwater. Despite this, the PFOS concentration in a groundwater intake area 1.9 km from the pollutant source was predicted to exceed the limits set for drinking water, in contrast to earlier predictions based solely on monitoring. The study demonstrates the importance of modeling for groundwater management as the data on AFFF usage and composition, and on soil and groundwater contamination with perfluorinated compounds and co-pollutants typically are limited in terms of the spatial and temporal scale of contamination. (C) 2021 American Society of Civil Engineers.