Modeling of Contaminant Biodegradation and Compound-Specific Isotope Fractionation in Chemostats at Low Dilution Rates

Amount-dependent isotopic fractionation during compound-specific isotope analysis.

The performance of a gas chromatography-combustion-isotope ratio mass spectrometry system (GC-C-IRMS) with respect to the dependence of delta(13)C values on the amount of sample is presented. Particular attention is paid to the localization of the amount-dependent isotopic fractionation within the system. Injection experiments with varying amounts of gases (CO(2), n-hexane, and toluene) reveale...

Stable carbon isotope fractionation during aerobic biodegradation of chlorinated ethenes.

Stable isotope analysis is recognized as a powerful tool for monitoring, assessing, and validating in-situ bioremediation processes. In this study, kinetic carbon isotope fractionation factors (epsilon) associated with the aerobic biodegradation of vinyl chloride (VC), cis-1,2-dichloroethylene (cDCE), and trichloroethylene (TCE) were examined. Of the three solvents, the largest fractionation ef...

Compound-specific isotope analysis

The isotopic composition, e.g. 14C/12C, 13C/12C, 2H/1H, 15N/14N and 18O/16O, of matter elements is heterogeneous. It is ruled by physical, chemical and biological mechanisms. Isotopes thus be enable to follow the fate of mineral and organic compounds during biogeochemical transformations. The determination of the isotopic composition of organic substances occurring at trace level into very comp...

Isotope Effects, Isotope Separation and Isotope Fractionation

Carbon isotope fractionation during aerobic biodegradation of n-alkanes and aromatic compounds in unsaturated sand

Microcosm experiments were conducted to quantify carbon isotope fractionation during aerobic biodegradation of n-alkanes (from C3 to C10) and monoaromatic hydrocarbons in unsaturated alluvial sand. In single compound experiments with n-alkanes, the largest enrichment factor was obtained for propane ( 10.8 ± 0.7‰). The magnitude of the enrichment factor decreased with increasing number of carbon...