Distribution of chlorinated organic pollutants in a wide variety of soils from Europe and Asia: a multivariate statistical approach.

Principal component analysis was used to interpret the levels of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) previously determined in a wide variety of soils from Europe and Asia to (1) examine the interdependencies among them and chosen soil charaeteristics and (2) reveal PCB- and OCP-soil patterns throughout Europe and Asia. Loading values suggested correlations between the levels of certain compounds and soil characteristics, revealing the underlying structure of analyzed data; humus content, pH, and density correlated with the contents of p,p'-DDT, beta-hexachlorocyclohexane (HCH) and gamma-HCH, and clay content correlated with the concentrations of alpha-HCH and PCB 28. Component scores reflected relatively low concentrations of six "marker" PCBs in most of the soils, pointing out the outliers in the proximity of the local PCB sources. PCB loads in the 1990s and early 2000s were lower than the ones in 1980 and 1956, and they coincided with the soil levels in 1944. PCBs 138, 153, and 180 had the greatest influence of the six investigated congeners on soil-pattern differences. In relation to the OCP soil loads, the score plot revealed regions with recent and/or enhanced application of DDT and HCH.