Influence of different emission sources on atmospheric organochlorine patterns in Germany

The concentrations of organochlorine parent substances such as p,p′-DDT (2,2-bis(chlorophenyl)-1,1,1-trichloroethane) and lindane (γ-hexachlorocyclohexane (HCH)) as well as of their metabolites and conversion products, chlorobenzenes (CBz) and polychlorinated biphenyl congeners (PCBs), were determined both in the gas phase and in the particle bound fraction at 10 locations in Germany. The ratios between parent substances and possible degradation products were influenced by different gaseous point-source emissions. Factors of site-related degradation products are dependent on the emission source. Surprisingly, the highest degradation ratios of p,p′-DDT to DDE and DDD were not calculated at +20 °C, but at −19 °C. This indicates that heavy metals, black carbon and other organic substances such as PAHs may catalyse degradation reactions on particles because of higher condensation of all these substances at lower temperatures. To detect hidden characteristic of pollutant patterns that are dependent on the specific emission source and on typical degradation processes, the principal component analysis (PCA) results suggested that the organochlorines appear to be associated. Comparatively higher concentrations of DDX and HCH isomers mean at some sites also higher concentrations of CBz and PCBs, without an additional source being recognizable.