PhD Candidate · Hydrology · University of Freiburg

Tracing TFA — from the atmosphere to the human body

Trifluoroacetic acid is accumulating silently in our environment — in rainfall, rivers, groundwater, forests, and increasingly in ourselves. I study where it comes from, how it moves, and what it means for the health of our planet.

Chair of Hydrology, University of Freiburg immanuel.frenzel@hydrology.uni-freiburg.de

About

I am a PhD candidate at the Chair of Hydrology, University of Freiburg, working in the group of Prof. Jens Lange. My research centres on trifluoroacetic acid (TFA) — the smallest member of the PFAS family and one of the most mobile and persistent contaminants on Earth.

TFA enters the environment through the atmospheric degradation of fluorinated refrigerant gases, through agricultural pesticides, pharmaceuticals, and everyday household products. Once in the water cycle, it does not degrade. Concentrations in rainfall, groundwater, rivers, and plants are rising globally — and the public debate has barely begun.

My work spans the full cycle: from catchment-scale hydrology in the Black Forest, to mass balances in urban sewer systems, to the question of how much TFA humans are actually exposed to — and how much ends up in our bodies. I combine field sampling, isotope tracing, and hydrological modelling to understand TFA's sources, transport, and fate. Beyond the science, I feel a responsibility to communicate these findings and move the conversation beyond drinking water thresholds towards a fuller reckoning with PFAS exposure.

Publications

2026Published

Diffuse sources of TFA: atmospheric and terrestrial inputs, retention and pathways at the catchment scale

Frenzel, I., Nöltge, D., Freeling, F., Müller, M., and Lange, J.

Hydrology and Earth System Sciences, 30, 1969–1997

2025Under review

A wastewater balance reveals unexpectedly high human TFA exposure

Frenzel, I., Hilgert, P., Herbstritt, B., Nöltge, D., Müller, M., and Lange, J.

Scientific Reports — under review

Projects

TFA in Forest Ecosystems

An incubator project funded by the Future Forests cluster investigating TFA occurrence in organic soil, litter, leaves, and needles across seasons. As environmental TFA concentrations continue to rise, this study provides a first dedicated dataset on TFA's role in forest ecosystems — a critical gap in current knowledge.

Active · 2026

TFA in the Dreisam Catchment

A two-year weekly monitoring campaign in the mountainous Dreisam catchment (Black Forest), tracking TFA alongside isotope and ion tracers across nested sub-catchments, precipitation, and hillslope springs — revealing how subsurface stormflow controls TFA mobilisation from soils under wet conditions.

Completed

Human TFA Exposure — Urine Sampling Campaign

A planned direct measurement campaign to quantify TFA in human urine samples. Moving beyond indirect estimates, this study will establish actual human body burden and help determine the contribution of food, pharmaceuticals, personal care products, and household activities to internal TFA loads.

Planned