Atmospheric flux, transport and mass balance of 210Pb and 137Cs radiotracers in different regions of Romania

• A total of 12 cores from seven different areas of Romania (Bihor County area, Ighiel area, Red Lake area, Mluha Peatbog, Mohos Peatbog, Semenic Peatbog and Danube Delta area) were chosen for soil and peat 210Pb and 137Cs flux and inventory measurements.
• Eleven sediment cores from the Red Lake, Romania were analyzed for catchment/lake transfer factor of 210Pb.
• Measurements were carried out using gamma spectrometry (HPGe detectors) for the determination of 210Pbtotal, 210Pb (226Ra) and 137Cs in case of soil cores and alpha spectrometry (PIPS detectors) for 210Pbtotal (210Po).

This study focuses on the determination of 210Pb and 137Cs fluxes from different areas in Transylvania, Romania and on the determination of transport and mass balance within the lacustrine system of Red Lake. In order to achieve this, samples were taken from six different locations (Bihor County area, Ighiel area, Red Lake area, Mluha Peatbog, Mohos Peatbog and Zanoaga Rosie Peat bog in the Semenic Mountains) throughout Romania, these being compared to the values of the Danube Delta area. The activity concentrations of the soil samples were measured by gamma spectrometry (HPGe detector) for both 210Pbtotal, 210Pbsup (226Ra) and 137Cs, while peat samples were measured by both alpha (210Po) spectrometry (PIPS detectors) as well. The mean value for the 210Pb flux was measured in the Danube Delta region (42±8 Bq m−2 yr−1), while the highest was measured in the Semenic Peatbog (227±54 Bq m−2 yr−1); the average being 132±8 Bq m−2 yr−1. In case of 137Cs the mean was 298±3 Bq m−2 yr−1, maximum being 1683±15 Bq m−2 yr−1 in case of Ighiel area and minimum being 32±1 Bq m−2 yr−1 in the Danube Delta region. In case of the Red Lake, from the total inventory of 410±23 Bq m−2 yr−1 in the sediments, the loss by outflows is 100±12 Bq m−2 yr−1, the catchment to lake transfer factor being 0.84%.