Natural background levels of trifluoroacetate in rain and snow

It has been shown that some of the fluorinated ethane derivatives being int roduced as CFC-replacements can be transformed to TFA (trifluoroacetate) in the atmosphere. Moreover, TFA is extremely stable in the environment, and this has raised questions regarding how widespread TFA is in the environmen t. We found that TFA is ubiquitous in precipitation: samples of rain from I reland and Poland and snow from Canada, Sweden, New Zealand, and East Antar ctica contained 1-1100 ng/L, and, studying a firn core drilled in Antarctic a, concentrations of 3-56 ng/L were measured in layers formed during the 19 th century. We have confirmed the preindustrial presence of significant bac kground concentrations of trifluoroacetate in historic precipitation sample s from the analysis of firn. Extensive procedures were enforced to prevent sample contamination.