Stable chlorine and carbon isotope measurements of selected chlorinated organic solvents

Abstract Stable Cl and C isotope ratio results for 3 selected chlorinated solvents, perchloroethylene (PCE), trichloroethylene (TCE) and 1,1,1-trichloroethane (TCA) provided by 4 different manufacturers are presented. The isotope ratio for all compounds range between −3.5 and +6.0‰ for δ 37 Cl and from −37.2 to −23.3%. for δ 13 C . The greatest 37 Cl difference between manufacturers is observed in the TCE samples which show δ 37 CI values of −2.5%o for PPG, +2.43‰ for ICI and +4.4‰ for DOW. TCAs show a smaller range (−2.4 to +2.0‰), while the TCEs have slightly different 37 Cl contents. The 13 C data show the most distinct δ 13 C values for PCEs (−23.3 for DOW, −24.1 for Vulcan, −33.8 for PPG and −37.2‰ for ICI) while both TCEs and TCAs show a smaller δ 13 C range, but still distinct differences. These preliminary data suggest that each manufacturer and solvent type may have distinctive δ 637 Cl and δ 13 C values. These results show that by using a combination of 37 Cl and 13 C, there is a potential to indicate a specific source of chlorinated solvents, as well as an ability to delineate contamination episodes caused by these compounds in groundwaters.