With the implementation of European Water Frame Work Directive (EU-WFD), the pollution sources in
the River Elbe were assessed by the River Basin Community Elbe (RBC Elbe). Contaminated old sediments
played the most significant role for inorganic and organic pollution. In terms of further improvement of
the water quality in the river system, a prioritization of the known pollution sources is necessary, with
respect to the expected effect in the case of their remediation. This requires information on mobility of
contaminated sediments. To create a tool that allows the assessment of pollution trends in the catchment
area, event based flood investigations were carried out at a sampling site in the Middle Elbe. The investigations
were based on a comparable, discharge related sampling strategy. Four campaigns were performed
between 1995 and 2006. The majority of the investigated 16 elements (>80%) studied more
intensively in 2006 reached its maximum concentration during the first five days of the event. Only
the concentrations of B, Cl, and U declined with increasing discharge during the flood. The aim of the
study was to verify that each flood event is characterized by an internal structure of the water quality.
This structure is formed by the appearance of maximum values of water quality parameters at different
times during the event. It could be detected by descriptive and multivariate statistical methods. As a
result, internal structure of the water quality during the flood was influenced primarily by the source
of the metals in the catchment area and its distance from the sampling point. The transport of metals
in dissolved, colloidal or particulate form and changes of their ratios during the flood were however,
not decisive for the formation of the structure. Our results show that the comparison of the structures
obtained from events in different years is indicative of the pollution trend in the catchment area.
Exemplarily the trend of the metal pollution in the River Elbe will be discussed.