COMPOUND SPECIFIC STABLE ISOTOPE ANALYSIS: RESEARCH FRONTIERS IN ISOTOPE HYDROLOGY AND WATER RESOURCES MANAGEMENT

摘要

Compound Specific Isotope Analysis (CSIA) - the characterization of stableisotope compositions of individual contaminant compounds dissolved in groundwater,sparked a revolution in the interface between isotope geochemistry and contaminanthydrogeology. Stable isotope fingerprints can provide diagnostic tools to identifyand differentiate sources of contamination. Furthermore CSIA rapidly proved anovel method for investigation of both abiotic and biotic remediation potential atcontaminated sites. Several novel developments in CSIA are directly relevant to movingapplications of this field from point source contamination to larger regional watershedand ground water resource management applications. The limits of sensitivity anddetection limit are being pushed back to facilitate the application of CSIA to lowconcentrations of contaminants in more diffuse sources. Multi-isotope approachessuch as incorporation of both carbon and hydrogen isotope signatures, which to datehave been used primarily for non-chlorinated hydrocarbons, are now being extendedto investigation of chlorinated hydrocarbon compounds. Improved detection limits andchromatography are facilitating applications of CSIA to new classes of compoundsincluding pesticides, and chlorinated aromatics, where the presence of many isomerspresents both an analytical challenge and a challenge for identifying promising lines ofevidence for biodegradation.