Isotope applications in environmental investigations: Theory and use in chlorinated solvent and petroleum hydrocarbon studies

Abstract

Abstract Isotope applications are gaining acceptance for use in surface water and groundwater investigations, complementing traditional geochemistry and physical hydrology techniques. Recent developments in analytical methodologies and in the understanding of isotope dynamics now allow the use of isotopes to investigate sources and fate of common groundwater contaminants such as chlorinated solvents and petroleum hydrocarbons. Contaminants with unique isotopic signatures may facilitate the determination of contaminant sources in complex plumes. Degradation of chlorinated solvents and some petroleum hydrocarbons impart unique isotopic signatures on both the original contaminant and the degradation product or products that provide verification of degradation. Use of a Rayleigh‐type model may allow determination of degradation extent. Coupled with models of contaminant fate and transport, degradation extent may be useful for determining degradation rates. © 2001 John Wiley & Sons, Inc.