National screening study on 10 perfluorinated compounds in raw and treated tap water in France.

The occurrence of seven perfluoroalkyl carboxylates (PFCAs) and three perfluoroalkyl sulfonates (PFASs) was studied in raw- and treated-water samples from public water systems. Two sampling campaigns were performed during the summer of 2009 and in June 2010. Sampling was equally distributed across the 100 French departments. In total, 331 raw-water samples and 110 treated-water samples were analyzed during this study, representing approximately 20% of the national water supply flow. Concentrations of perfluorinated compounds (PFCs) were determined using automated solid-phase extraction and liquid chromatography-tandem mass spectrometry. In raw-water samples, the highest individual PFC concentration was 139 ng/L for perfluorohexanoic acid (PFHxA). The sum of all of the determined components was >100 ng/L at three sampling points (199, 117, and 115 ng/L). Of the investigated PFCs, perfluorooctane sulfonate (PFOS), perfluorohexane sulfonate (PFHxS), perfluorooctanoic acid (PFOA), and PFHxA predominated (detected in 27%, 13%, 11%, and 7% of samples, respectively). Geographical variability was observed, with departments crossed by major rivers or with high population densities being more affected by PFC contamination. Compared with raw water, short-chain PFCAs, but not PFASs, were found in higher abundance in treated water. This difference suggests a relative effectiveness of certain water treatments for the elimination of PFASs but also a possible degradation of PFCA precursors by water-treatment processes. Our investigations did not show any heavily contaminated sites. In treated-water samples, the highest individual PFC concentration was 125 ng/L for PFHxA. The sum of all of the determined components was >100 ng/L at one sampling point (156 ng/L). The values observed for PFOS and PFOA in drinking water were not greater than the health-based drinking-water concentration protectives for lifetime exposure that have been defined for other countries.