Université de Neuchâtel

Does the Rayleigh equation apply to evaluate field isotope data in contaminant hydrogeology?

Abe, Yumiko ; Hunkeler, Daniel

In: Environmental science & technology, 2006, vol. 40, no. 5, p. 1588-1596

Stable isotope data have been increasingly used to assess in situ biodegradation of organic contaminants in groundwater. The data are usually evaluated using the Rayleigh equation to evaluate whether isotope data follow a Rayleigh trend, to calculate the extent of contaminant biodegradation, or to estimate first-order rate constants. However, the Rayleigh equation was developed for homogeneous...

Université de Neuchâtel

Evaluating the fate of chlorinated ethenes in streambed sediments by combining stable isotope, geochemical and microbial methods

Abe, Yumiko ; Aravena, Ramon ; Zopfi, Jakob ; Parker, Beth ; Hunkeler, Daniel

In: Journal of Contaminant Hydrology, 2009, vol. 107, no. 1-2, p. 10-21

The occurrence of chlorinated ethene transformation in a streambed was investigated using concentration and carbon isotope data from water samples taken at different locations and depths within a 15×25 ms tudy area across which a tetrachloroethene (PCE) plume discharges. Furthermore, it was evaluated how the degree of transformation is related to groundwater discharge rates, redox conditions,...

Université de Neuchâtel

Carbon and chlorine isotope fractionation during aerobic oxidation and reductive dechlorination of vinyl chloride and cis-1,2-dichloroethene

Abe, Yumiko ; Aravena, Ramon ; Zopfi, Jakob ; Shouakar-Stash, O ; Cox, E ; Roberts, J.D ; Hunkeler, Daniel

In: Environmental science & technology, 2009, vol. 43, no. 1, p. 101-107

The study investigated carbon and chlorine isotope fractionation during aerobic oxidation and reductive dechlorination of vinyl chloride (VC) and cis-1,2-dichloroethene (cDCE). The experimental data followed a Rayleigh trend. For aerobic oxidation, the average carbon isotope enrichment factors were -7.2‰ and-8.5‰ for VC and cDCE, respectively, while average chlorine isotope enrichment...

Université de Neuchâtel

Use of stable isotopoe analyses to assess natural attenuation of chlorinated ethenes in groundwater

Abe, Yumiko ; Hunkeler, Daniel (Dir.)

Thèse de doctorat : Université de Neuchâtel, 2007 ; Th.1970.

Chlorinated ethenes are among the most frequently detected groundwater contaminants in industrially developed countries. Although their degradation pathways have been understood, assessing the progress of natural attenuation of chlorinated ethenes still remains a challenge. This thesis explored the possibilities and limits of the use of compound-specific stable isotope analysis as a field...