Carbon, Hydrogen and Chlorine Stable Isotope Fingerprinting for Forensic Investigations of Hexachlorocyclohexanes

Multielemental stable isotope analysis of persistent organic pollutants (POPs) has the potential to characterize sources, sinks, and degradation processes in the environment. To verify the applicability of this approach for source identification of hexachlorocyclohexane (HCHs), we provide a data set of carbon, hydrogen, and chlorine stable isotope ratios (δ¹³C, δ²H, δ³⁷Cl) of its main stereoisomers (α-, β-, δ- and γ-HCHs) from a sample collection based on worldwide manufacturing. This sample collection comprises production stocks, agricultural and pharmaceutical products, chemical waste dumps, and analytical-grade material, covering the production time period from the late 1960s until now. Stable isotope ratios of HCHs cover the ranges from -233‰ to +1‰, from -35.9‰ to -22.7‰, and from -6.69‰ to +0.54‰ for δ²H, δ¹³C, and δ³⁷Cl values, respectively. Four groups of samples with distinct multielemental stable isotope fingerprints were differentiated, most probably as a result of purification and isolation processes. No clear temporal trend in the isotope compositions of HCHs was found at the global scale. The multielemental stable isotope fingerprints facilitate the source identification of HCHs at the regional scale and can be used to assess transformation processes. The data set and methodology reported herein provide basic information for the assessment of environmental field sites contaminated with HCHs.