Compound-Specific Isotope Analysis (CSIA) is an advanced analytical technique that measures stable isotope ratios (e.g., ¹³C/¹²C, ²H/¹H) in individual organic compounds rather than bulk samples. CSIA is used to identify contaminant sources (fingerprinting), distinguish biodegradation from abiotic transformation processes, and differentiate true degradation from physical processes such as dilution or volatilization.
In environmental remediation, CSIA provides direct lines of evidence for contaminant transformation and is widely applied in performance monitoring, site assessment, and regulatory decision-making for complex subsurface systems.
