Stable chlorine and carbon isotope measurements of selected chlorinated organic solvents

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‰ forδ37Cl and from −37.2 to −23.3%. forδ13C. The greatest37Cl difference between manufacturers is observed in the TCE samples which showδ37CI 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 different37Cl contents. The13C data show the most distinctδ13C 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 smallerδ13C range, but still distinct differences. These preliminary data suggest that each manufacturer and solvent type may have distinctiveδ637Cl andδ13C values. These results show that by using a combination of37Cl and13C, 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.