Small but Everywhere: TFA Found Widespread in German Soils
Source: BAM
Per- and polyfluorinated alkyl substances (PFAS) are among the greatest environmental chemical challenges of our time because of their exceptional persistence. Trifluoroacetic acid (TFA) is an emerging pollutant among them. It is the smallest perfluorinated carboxylic acid and is highly persistent and extremely mobile. It is also expected to increase in the environment due to ongoing industrial release and atmospheric formation. Despite this, reliable data on TFA contamination in soil, a critical interface between ecosystems, agriculture, and human exposure, remain scarce, largely because standardized analytical methods are lacking.
Our study helps to close this gap. We systematically compared six methods described in the literature for determining TFA in soils and revealed their weaknesses. Based on these findings, we developed and validated a new, robust sample preparation method. This method combines isotope dilution with hydrophilic interaction chromatography and tandem mass spectrometry (HILIC-MS/MS), achieving high recovery rates (104%), a detection limit of 0.015 ng/g, and a quantification limit of 0.045 ng/g.
The validated method was applied to 100 soil samples collected from grassland and farmland across Germany, representing the first large-scale assessment of TFA in soils. TFA was detected in all samples, confirming its ubiquitous presence. Concentrations ranged from 0.2 to 14 ng/g, with localized hotspots indicating elevated contamination. Statistical analysis revealed no clear dependence on land use or sampling region. Instead, a weak to moderate correlation with dry bulk density suggests that soil structure and organic matter content influence TFA retention. These results support the hypothesis that soils act as long-term reservoirs for TFA, with precipitation likely serving as a major input pathway.
Overall, this work demonstrates that soils contain some of the highest environmental TFA burdens reported to date and that its behavior is more complex than previously assumed. The results highlight the need for harmonized monitoring strategies and further research into the factors controlling TFA accumulation and mobility. Given the expected rise of TFA emissions, understanding its fate in soils is essential for future risk assessment and environmental regulation.
Approaches towards sensitive and reliable determination of trifluoroacetic acid (TFA) from German grass- and farmland soils
Juliane Scholl, Emelie Meiers, Tatjana Mauch, Jan Lisec, Thomas Sommerfeld, Karlheinz Weinfurtner, Hajo Haase, Matthias Koch
Chemosphere, Volume 382, August 2025