Cs and [sup.210]Pb radionuclides in open and closed water ecosystems

The aim of this study was to determine the level of radionuclide concentration in sediment cores in two different water ecosystems; one closed and one open. Based on this data the changes in these ecosystems were interpreted. Two sediment cores from the Dobczyce reservoir and the Smreczynski Staw Lake were collected and divided into 1 cm thick sub-samples. The samples were air dried and homogenized. The [sup.137]Cs and [sup.210]Pb ([sup.210][Pb.sub.sup], [sup.210][Pb.sub.total], [sup.210][Pb.sub.uns]) concentrations were measured using gamma and alpha spectrometry. Results showed that the [sup.137]Cs concentration in the Dobczyce reservoir is lower than in the Smreczynski Staw Lake. Total [sup.210]Pb concentration in the Dobczyce reservoir was around 70 Bq [kg.sup.-1] and in the Smreczynski Staw Lake was about 500 or 1,200 Bq [kg.sup.-1] with the decreasing tendency in the sediment core. Sediments are very important constituents of water ecosystems. In spite of the young age of the Do bczyce reservoir, the [sup.137]Cs and [sup.210]Pb radionuclides were very useful in understanding of the processes which have taken place in these ecosystems. The estimated sedimentation rate indicated such processes as regular sedimentation, mixing of sediments or floods. In the Smreczynski Staw Lake the changes have reflected the changes which took place in the Tatra Mountains. Keywords Sediments core * Radionuclide [sup.210]Pb, [sup.137]Cs * Alpha and gamma spectrometry