Simulation and evaluation of potential physical and mass transfer phenomena governing congener group profiles in soils near combustion sources

Trace quantities of PCDDs are emitted on particulates from many combustion processes. The composition of the complex mixture is frequently expressed as congener group ratios. Although congener group ratios may vary for different sources, environmental samples appear to have a characteristic composition different than those associated with known sources. In lieu of identifying an unknown dominant source, having a congener group profile like the background profile, it is necessary to postulate the existence of an unknown physical/chemical process(es) to explain the differences. Several possible explanations are plausible. In this study, these phenomena are reviewed and evaluated, using simulation techniques, for comparison with present day observations on PCDD profiles in environmental samples.