Stable chlorine and carbon isotopic compositions of selected semi-volatile organochlorine compounds

To assess whether the isotopic composition of semi-volatile organochlorine compounds (SVOCs) may be a useful tool, we measured the bulk δ37Cl and δ13C values of several pesticides and Aroclor mixtures from different suppliers. Overall, the δ37Cl and δ13C values ranged from −5.10 to +1.22‰ and −31.63 to −22.39‰, respectively. These values are narrower than the ranges observed previously for volatile organic contaminants (VOCs). In particular, the isotopic compositions of the Aroclor mixtures were very tightly constrained for both chlorine and carbon. We also observed that SVOCs synthesized from hexachlorocyclopentadiene had the most enriched δ37Cl values. These data provide a baseline for future work employing isotope ratios to study the environmental fate of SVOCs.