Enzymaktivitäten in Poren- und Oberflächenwässern unterschiedlich belasteter Elbabschnitte

River sediments vary in their properties in space and time. These variations can be well demonstrated at reference areas. As part of investigations of microbial activities in sediments from the River Elbe, pore waters and river waters were studied. We aristed to differentiate between reference sites that were heavily polluted by point and non-point sources on the one hand and less polluted ones where only background pollution existed, on the other. For this purpose samples were taken once or twice per month in a field between two groynes immediately downstream of the waste-water input of the chemical plant Fahlberg List and in the oxbow lake Alte Elbe/Klieken. In-vivo enzymatic tests [1] were used to determine potential glucosidase, alanin-aminopeptidase and dehydrogenase activities, respectively. It was shown that the invivo enzymatic tests used are suitable to distinguish between the sediments from the different reference sites. In the pore water from the Fahlberg List site significantly higher biological activities could be measured than in that from the less polluted Alte Elbe/Klieken site. At the same time considerably higher fluctuations in the parameters were observed at the Fahlberg List site, caused by varying waste-water discharges. In contrast to the sediments, the enzymatic activities surface waters from both sites showed in similar intensity and seasonal behaviour, which were closely connected to the primary and secondary production in the respective reaches.