Trifluoroacetic Acid (TFA) in Groundwater and Surface Water: Mapping, Trends and Regulatory Perspectives

Sammanfattning

Trifluoroacetic acid (TFA), an ultra-short chain PFAS, is highly persistent, mobile in water, and currently not explicitly regulated in Swedish- or other European water legislation apart from in Denmark. This thesis investigates the occurrence, trends, and potential pesticide-derived formation of TFA in Swedish ground- and surface waters along with regulatory implications on a national and international level. A dataset of 437 Swedish TFA measurements from 2023-2026 was analysed, covering 19 of 21 counties and 111 of 290 municipalities in Sweden. Results show that TFA is widespread across Sweden, with a national mean concentration of approximately 360 ng/l with indications of a southward concentration gradient. Skåne County had both the highest mean and highest maximum concentration measuring 600 ng/l and 2700 ng/l respectively. Trend analyses from 29 monitoring stations and 128 observations indicated increasing concentrations, with Linear Mixed Model and Robust Linear Model estimates showing annual increases in Sweden of 19.65% and 16.86%, respectively. Swedish pesticide sales data from 2000-2024 showed increasing input of TFA-precursor substances, with 2024 reaching the highest studied level. Mass-balance modelling suggests potential pesticide-derived TFA accumulation in Swedish waters of 130-150 tonnes by 2025 since year 2000. The conclusion is that expanded monitoring, improved knowledge of pesticide degradation pathways, and precautionary regulation are needed due to TFA’s persistence and uncertain long-term effects on human health and the ecosystem.