Dioxin and furan signatures in northern Canadian soils: Correlation to source signatures using multivariate unmixing techniques

PCB and PCDD/F analysis carried out during assessments of abandoned military sites in the Canadian North allowed an opportunity to test the utility of multivariate statistical techniques in the assignment of source signatures to contaminated soil samples. A combination of principal component analysis (PCA) and polytopic vector analysis (PVA) was used to assess the inputs of PCDD/Fs to soils along with source signatures obtained from the literature. The composition of background samples obtained at least 20 km from any local source contamination showed a clear correlation with combustion sources. Soil samples taken in the vicinity of the military sites showed evidence of PCDD/F contamination associated with the extensive use and spillage of PCBs in transformer fluids and the use of chlorophenols as wood preservatives. There was evidence that significant changes in signature occur with distance from the source. The results of the statistical analysis in assigning source signatures agreed well with field observations.