The monitoring programme designed by the TZW focused on the atmospheric deposition of the drinking water relevant contaminant trifluoroacetate (TFA). Precipitation samples were collected at eight different locations of the German National Meteorological Service’s (DWD) network and analysed for TFA. As a result, the contribution of atmospheric deposition to the TFA emission into drinking water resources can be reliably estimated and statements made about the probability of the potential involvement of additional, local TFA sources.
The anthropogenic sources of trifluoroacetate (TFA) are manifold: industrial discharge, wastewater treatment plants, agriculture and, last but not least, the photochemical degradation of selected propellants and refrigerants and the subsequent input of atmospherically formed TFA via precipitation. Without knowledge of the individual contributions of the above-mentioned sources, it is not possible to derive effective mitigation measures, and diffuse input via precipitation has sometimes been put forward as a major unknown in previous investigations. The main objective of the TZW was, therefore, to close this knowledge gap towards a more effective protection of drinking water resources.
Over a period of 24 months, daily precipitation samples were collected at eight DWD stations and sent to TZW. From these individual samples, precipitation-equivalent monthly composites were prepared for each site and the concentration of TFA was determined in these samples. For Germany, a precipitation-weighted mean value of 0.37 µg/L was derived for the investigated period. TFA concentrations in drinking water and drinking water resources above 1 µg/L are, thus, a sure indication of the involvement of additional sources of TFA. The results of this study, which is also unique on the international level, can be used for source apportionment to elucidate elevated TFA contaminations in water bodies and as a reference for subsequent precipitation monitoring programmes.
Publications:
Freeling, F., Behringer, D., Heydel, F., Scheurer, M., Ternes, T.A., Nödler, K., 2020. Trifluoroacetate in Precipitation: Deriving a Benchmark Data Set. Environ. Sci. Technol. 54 (18), 11210–11219.
Behringer, D., Heydel, F., Gschrey, B., Osterheld, S., Schwarz, W., Warncke, K., Freeling, F., Nödler, K., Henne, S., Reimann, S., Blepp, M., Jörß, W., Liu, R., Ludig, S., Rüdenauer, I., Gartiser, S., 2021. Persistent degradation products of halogenated refrigerants and blowing agents in the environment: type, environmental concentrations, and fate with particular regard to new halogenated substitutes with low global warming potential (Link to the final report)
