Stable Carbon Isotope Fractionation During 1,4-Dioxane Biodegradation

Compound Specific Isotope Analysis (CSIA) has been successfully used as a monitoring tool to assess the biodegradation of various organic contaminants. In this study, we report the development of CSIA method for 1,4-dioxane, a probable carcinogen and an important emerging contaminant in water supplies. This method was applied to determine kinetic carbon isotopic fractionation factor (ε) during the aerobic biodegradation of dioxane by Pseudonocardia dioxanivorans CB1190, which can grow using dioxane as its only source of carbon and energy. The fraction of 13C increased as biodegradation progressed, resulting in an ε value of −1.73 ± 0.14. Our study will provide a foundation for stable isotope-based monitoring tools for establishing natural attenuation and biodegradation of 1,4-dioxane in contaminated environments.