Modeling Uptake and Accumulation of Trifluoroacetic Acid (TFA) in Agricultural Crops

Trifluoroacetic acid (TFA) is an ultrashort-chain PFAS increasingly detected in precipitation, surface water, and agricultural environments, yet its accumulation in crops remains poorly quantified. This study presents a process-based modeling framework to simulate crop TFA uptake, integrating a TFA mass-balance module with three crop models (AquaCrop, SWAP-WOFOST and LINGRA-N-Plus). A full-factorial scenario analysis was conducted for five crops, three soil types, 30 years of weather data across three European agro-climatic zones, and ranges of crop parameters, environmental TFA concentrations (0.1-2 μg L-1), and transpiration stream concentration factor (TSCF; 0.16-0.64). Simulated biomass-weighted TFA concentrations ranged from 10 to 300 μg kg-1 dry weight and scaled proportionally with environmental concentration (elasticity = 1), TSCF (0.88), and the ratio of cumulative transpiration to biomass (1.175), which varied substantially across crops and climates. Grass and sugar beet exhibited the highest TFA accumulation, and maize the lowest. Model structure contributed substantially to overall uncertainty, particularly for grass. Simulated concentrations aligned literature values, supporting model plausibility. The framework provides a robust basis for estimating TFA accumulation and highlights the need for improved TSCF data and environmental monitoring.