Carbon isotope fractionation of chlorinated ethenes during oxidation by Fe2Â + activated persulfate

► The performance of in situ chemical oxidation (ISCO) is still difficult to assess. ► We investigated the potential of carbon isotope analysis as a new assessing tool. ► C isotope of PCE, TCE and DCE oxidized by persulfate activated by Fe2 + was measured. ► Enrichment factors of − 4.9‰ for PCE, − 3.6‰ for TCE and − 7.6‰ for cisDCE were obtained. ► Carbon isotope can potentially be used to estimate the ISCO treatment efficacy.