ABSTRACT
The degradation of CFCs during riverbed infiltration have been studied by sampling of monitoring wells next to the infiltration zone (sites at teh river Ruhr and Oder). At both studied sites the groundwater exhibits anaerobic conditions. High degradation rates have been derived from the low CFC concentrations in the fast moving groundwater. It must be concluded that CFCs are not suitable to trace the water movement or to date the groundwater age under these conditions of riverbed infiltration. But in combination with a conservative tracer the CFC measurement can indicate location of anaerobic bioactivity.
