Search for unidentified PCB sources in Swedish stream using semi permeable membrane devices *Per-Anders Bergqvist,, Ilona Jegorova, *Lijana Augulyte, Audrone Zaliauskiene Environmental Engineering, Kaunas University of Technology, Kaunas, Lithuania *Environmental Chemistry, Umeå University, SE-901 87 Umeå, Sweden Umeå Kaunas Introduction In 2003 several places polluted by PCB was identified in the stream Tvärån, Umeå city. Present study aims to identify the sources of PCB pollution to the stream. Sampling was performed in the area between the beginning of industrial site and intake to the river Umeå. Pollutant concentrations in the stream water fluctuate very rapidly depending on occasional releases and rain events. In order to obtain time average concentration of PCBs congeneres during few weeks integrative passive sampling method was chosen. Results and discussion TetraCB concentrations in sampling places TriCB concentrations in sampling places Materials and methods To investigate the bioavailable time weight average concentrations of PCBs in the stream of the ??? different sites (map), passive sampling was performed in summer 2003 using semipermeable membranes devices. To provide controls for the exposure during deployment in the field, two single SPMDs were exposed to air during deployment and retrieval in the same manner as the SPMD samples. The SPMDs were then dialyzed in cyclopentane: dichlormethane. 40 µl of labeled C13 and deutered compounds were used as internal standards were added to the extract and then remaining lipids were separated from the POPs by using high-resolution gel permeation chromatography (HR-GPC). To the sample 40 l of recovery standard dibenzofurane (RS) was added. The analysis of organic compounds was done using high-resolution gas chromatography/low-resolution mass spectrometry (HRGC/LRMS) - system operating in selected ion recording (SIR) mode. PentaCB concentrations in sampling places HexaCB concentrations in sampling places HeptaCB concentrations in sampling places OctaCB concentrations in sampling places Conclusions: Integrated sampling method and PCB-congener analysis have allowed to identify PCB pollution sources Sum PCB concentrations in sampling places Total PCB concentrations in sampling places Acknowledgements – We wish to acknowledge Umea University, Socrates program and Kaunas University of Technology for financial support.