The biological and physico-chemical uptake of radiocesium by particulate matter of natural origin (Baltic Sea)

Artificial radionuclides ⁹⁰Sr and ²⁴¹Am in the sediments of the Baltic Sea: total and spatial inventories and some temporal trends

The Baltic Sea was contaminated by radioactivity following global nuclear fallout and later by the Chernobyl accident. Despite the decrease of radioactivity caused by radioactive decay, radionuclides have a prolonged residence time in the water of the Baltic Sea due to slow water exchange and relatively rapid sedimentation. Very little is known about the amounts or spatial differences of ⁹⁰Sr and ²⁴¹Am in the Baltic Sea sediments. In this study, 20 sediment cores taken around the Baltic Sea were investigated to estimate inventories of these radionuclides. The rough results show that the Chernobyl fallout added the amount of ⁹⁰Sr in the same areas where the increase of ¹³⁷Cs can be detected, whereas this is not the case for ²⁴¹Am which is more evenly distributed in the sea bottom. In addition, local differences occur in the concentrations. These results are an important amendment to the radioactivity baseline of the Baltic Sea.

Activity concentration of caesium-137 in seawater and plankton of the Pomeranian Bay (the Southern Baltic Sea) before and after flood in 1997

Activity coefficients of 137Cs determined during culminating flood waters in August 1997 in the estuary of the Oder River, discharging to the Pomeranian Bay as well as in the coastal and open-seawaters of the Bay, did not show enhanced levels of the nuclide as compared to those measured before the flood. It is thus concluded that the flood did not contribute to releasing the nuclide from eroded soil particles. The bioconcentration factors of 137Cs in the riverine plankton has been found to be one to two orders of magnitude higher than those determined in the Pomeranian Bay plankton.