Source identification of PCBs in Antarctic air by compound-specific isotope analysis of chlorine (CSIA-Cl) using HRGC/HRMS

Occurrence of persistent organic pollutants (POPs) in the Polar Regions has received great concern in the past several decades due to their long-term adverse effect on biological health in such a fragile environment. How-ever, there is still argument over their source and fate in these pristine areas. Here we attempted to use a novel approach (compound-specific isotope analysis of chlorine, CSIA-Cl) to identify the source of POPs in Antarctic air by comparison with the source area. The results showed that the relative isotope-ratio variation of Cl (837Cl ') values showed a large variation from -137 to 9.04 %o in the gas-phase samples, and a significantly negative correlation (p < 0.01) was obtained against the logKoa values of PCBs. There were no significant correlations (p > 0.05) observed between the 837Cl ' values and meteorological parameters except for PCB-28 which showed temperature dependence. By contrast, the 837Cl ' values in the urban (Beijing) air ranged from -12.8 to 2.03 %o. The larger variation of delta 37Cl ' in Antarctic air indicated evidently influence of long-range atmospheric transport (LRAT) on isotopologue fractionation of PCBs. This study may shed light on the application of CSIA-Cl for source identification of chlorinated POPs on a large scale.

Automated summary

The occurrence of persistent organic pollutants (POPs) in the Polar Regions has caused concerns due to their long-term adverse effects on the fragile environment. However, the source and fate of these pollutants in pristine areas are still being debated. In this study, a novel approach called compound-specific isotope analysis of chlorine (CSIA-Cl) was used to identify the source of POPs in Antarctic air by comparing it with the source area. The results showed that the isotope-ratio variation of Cl values in the gas-phase samples exhibited a large variation and was correlated with the logKoa values of PCBs. The study highlights the potential application of CSIA-Cl for source identification of chlorinated POPs on a large scale.