Dioxin, dioxin-like PCBs and organotin compounds in the river Elbe and the Hamburg harbour: Identification of sources

Using neural networks (in this case the Kohonen network) and a multivariate statistical method - the hierarchical cluster analysis -, a classification of dioxin data has been carried out. A principal conclusion, which can be drawn, is that a significant source of dioxin in the river Elbe, Hamburg harbour, the soils of the flood plains of the river Elbe and in soils originating from dredging materials, has been shown to originate from the dioxin contaminated region of Bitterfeld. The results indicate that the dioxin contamination in the Bitterfeld region was caused partly by metallurgy processes, not just by chemical production. Furthermore, the results show that a main dioxin source responsible for the contamination of Hamburg surface waters, not influenced by the river Elbe, is of “thermal origin”. The river Elbe shows a characteristic butyltin pattern. The cause is probably a plant in Bitterfeld. The precise sources of the dioxin-like PCB are still unknown.