Use of dual carbon-chlorine isotope analysis to assess the degradation pathways of 1,1,1-trichloroethane in groundwater.

摘要: Abstract Compound-specific isotope analysis (CSIA) is a powerful tool to track contaminant fate in groundwater. However, the application of CSIA chlorinated ethanes has received little attention so far. These compounds are toxic and prevalent groundwater contaminants environmental concern. The high susceptibility like 1,1,1-trichloroethane (1,1,1-TCA) be transformed via different competing pathways (biotic abiotic) complicates assessment their subsurface. In this study, use dual C–Cl approach identify active degradation 1,1,1-TCA evaluated for first time an aerobic aquifer impacted by trichloroethylene (TCE) with concentrations up 20 mg/L 3.4 mg/L, respectively. reaction-specific carbon–chlorine (C–Cl) trends determined recent laboratory study illustrated potential 1,1,1-TCA. Compared slopes (Δδ13C/Δδ37Cl) previously dehydrohalogenation/hydrolysis (DH/HY, 0.33 ± 0.04) oxidation persulfate (∞), slope from field samples (0.6 ± 0.2, r2 = 0.75) closer one observed DH/HY, pointing DH/HY as predominant pathway aquifer. deviation could explained minor contribution additional processes. This result, along TCE measurements, confirmed that main source 1,1-dichlorethylene (1,1-DCE) detected 10 mg/L. demonstrates can strongly improve qualitative quantitative processes field.