With several multivariate statistical methods a classification of dioxin data has been tried. As a main result one significant source of dioxin in the river Elbe, in the harbour of Hamburg as well as in soils of the flooding areas of the river Elbe could be identified: the dioxin contaminated region Bitterfeld. Our statistical results indicate that the dioxin contamination in the Bitterfeld region was caused partly by metallurgy processes and not only by chemical production.