Prof. Michał Kowal (National Centre for Nuclear Research, NCBJ) talks about the complexities of theoretical work, long-lived and excited nuclear states, and the frontier of our knowledge about superheavy atomic nuclei.

Laboratory and field experiments have been conducted to study mobility of chromium and lead in

floodplain sediments. The main goal of the research was to verify a hypothesis whether changes of chromium

and lead concentration could be used to estimate the relative age of floodplain deposits. The basis for undertaking such research was the presence of weaving industry centers in the Obra River valley between the 16th and

the 19th century and using Cr and Pb compounds in paint recipes. The Cr and Pb contents were also analyzed in

three vertical profiles unaffected by the field experiments. The age of organic sediments in each of the profiles

was determined using the radiocarbon analysis. The results of the laboratory experiments have shown that the

highest contents of the elements were noted in the surface layer of the sediments placed in the column. However,

the contents decreased during the last phase of the experiments and both vertical and horizontal migration of

both elements was observed. A more intensive mobility was observed in the field test. Its cause could be the

changes of the groundwater level, floodplain inundation and pH conditions in alluvial deposits. Such processes

may have influenced migration of the compounds originating from the weaving industry production; Cr and Pb

contents detected in the profiles unaffected by the field experiment were too small to be used for relative dating of alluvial deposits. Moreover, the alluvial deposits with increased contents of the studied elements may be

older than the period of the weaving industry development. Cr and Pb mobility was especially intensive in the

profiles situated within the near bed zone of the floodplain due to regular inundation, and the activity of erosion

and accumulation processes entraining the studied elements back to transport in the river bed.

Research concerning changes or chosen chemical elements concentration in alluvial sediments was conducted in the lower course or the Obra river valley. The analyses of Fe, Mn, Cu, Zn, Ca, Mg and K concentration were done in a fragment or vertical profile, which was characterized by variable lithology. On the basis of statistical analysis (cluster analysis) an attempt was made to distinguish geochemical groups of alluvial sediments of the Obra river valley. Six geochemical groups, which represent reductive conditions within peat deposits, the environment ofllood sediments (inserts of fine sands within peats and sandy silts in the top of the profile) and the environment or river bed sediments (fine sands in the bottom part ofthe profile), were singled out. Results of the study show that it is possible to distinguish the above mentioned depositional environments on the basis of variations of sediments' chemical constitution.