Evidence for short-range transport of polychlorinated biphenyls in the Canadian Arctic using congener signatures of PCBs in soils

The Distant Early Warning (DEW) Line, a series of radar stations spanning the Canadian Arctic, is closing. In order to determine the environmental status of these installations, the Canadian Department of National Defence has sponsored an assessment of soil contamination, the partial results of which are presented here. A comparison of PCB concentrations in background samples taken from pristine areas near the radar sites and samples taken in remote locations (> 20 km distant) provides evidence for short-range redistribution of PCBs. Principal component analysis, which was used to highlight differences in congener composition, provided confirmation of this observation. The PCB congener signatures for background samples taken at the radar sites correlated well with PCB signatures from contaminated locations at the radar sites. In contrast, the congener signature attributed to long-range transport, contained a relatively higher proportion of more volatile congeners, which can be attributed to the increased atmospheric residence time.