Research Articles Distribution of PCDDs and PCDFs in Soils Collected from the Denver Front Range Principal Components Analysis of Diffuse Dioxin Sources

source of these contaminants on-site. Indeed, the relatively dif-fuse nature of the sample clusters would argue strongly against the presence of a single large source. Instead, the predominance of the PCDF congeners probably indicates the mixed industrial activities that took place on and near the site. Conclusion. PCA results indicate that PCDD/PCDF profiles in soils collected from the RMA differed from those collected from the outlying Denver areas but that a major source of these con-taminants was not present. Rather, the diffuse nature of sample clusters from the PCA indicated that the congener profile of RMA samples was most likely a result of the mixed industrial activities that historically have taken place on and near the site. PCA also indicated that many of the 'open area ' (peripheral site-wide) RMA soils samples did not differ from Denver are reference congener profiles. This finding was also true for sam