Carbon isotope fractionation during degradation of benzene, trichloroethene, and tetrachloroethene under ultraviolet light

Stable carbon isotope fractionation factors associated with the degradation of benzene, trichloroethene (TCE), and tetrachloroethene (PCE) under ultraviolet light (254 nm) have been measured experimentally using simple and inexpensive quartz reaction vessels equipped with a syringe valve and septum. Carbon isotope enrichment factors of ε_benzene = -6.2 ±0.3‰, ε_TCE = -6.8 ± 0.2‰, and ε_PCE =-4.1 ± 0.2‰ were obtained. The results demonstrate that the simple and inexpensive experimental design used in this study has potential application to determine isotope enrichment factors associated with degradation under conditions more representative of important atmospheric processes, and hence has future application to the study of the behavior of important trace gases such as non-methane hydrocarbons and other volatile organic compounds in the atmosphere.