Perchloroethene source delineation using carbon-chlorine isotopic analysis: field investigations of isotopic signature variability / Perchlorethen-Quellendifferenzierung mittels Kohlenstoff-Chlor-

When dealing with contaminated sites, identifying the source of contamination is critical for regulatory purposes. For chlorinated ethenes, previous studies have shown that dual carbon-chlorine (C-Cl) stable isotope analysis could be a key to address this issue as isotopic signatures vary between manufacturers and therefore, supposedly between sources. A successful application of this method relies on the assumption that different sources in the field will also show different signatures. Since the solvents used in the past are no longer available, this study aimed at investigating the extent of applicability of C-Cl stable isotope measurements for source identification based on field investigations. Ten sites which covered all of Switzerland and various sectors employing perchloroethene (PCE) were chosen. Differences were observed between some sites, suggesting that this method could be successfully applied. Other sites showed very similar isotopic signatures, indicating that this method applicability is site-specific. Additionally, the isotopic signature variability between sites was less significant than between the values previously reported for solvents from various manufacturers from North America. It was also confirmed that PCE reductive dechlorination should be considered when applying C-Cl isotope analysis for source identification. © 2015, Springer-Verlag Berlin Heidelberg.