Historical Profiles of Chlorinated Paraffins and Polychlorinated Biphenyls in a Dated Sediment Core from Lake Thun (Switzerland)

A dated sediment core from Lake Thun covering the last 120 years was analysed to get an overview of the histor ical trend of the chlorinated paraffin (CP) and polychlorinated biphenyl (PCB) deposition. The application of CPs and PCBs are similar, e.g. as plasticisers, flame retardants and cutting oils. Total CP concentrations obtained by GC-EI-MS/MS show a steep increase in the 1980s and a more or less stable level of 50 ng/g from then. The analysis of higher chlorinated SCCPs by GC-ECNI-LRMS revealed an increase of this class in recent years, which indicates its enhanced use. Furthermore, PCBs were analysed in the sediment samples by GC-EI-HRMS. The PCB concentrations peaked around 1969 (17.7 ng/g) and decreased to 1.3 ng/g in the surface layer corresponding to 2004. CP concentrations exceeded those of PCB by ca. a factor of three suggesting a much more pronounced use.