THE INTERACTIONS OF MN-54 WITH HUMIC SUBSTANCES OF FRESH-WATER SEDIMENT ORIGIN

The interactions of Mn-54 radionuclide with humic (HAB) and fulvic aci d (FAB) isolated from freshwater sediment of the Butoniga impoundment were studied in a freshwater system from Butoniga impoundment, and in a diluted seawater system from the Rasla Bay at elevated pH by high-vo ltage paper electrophoresis. rn this way, it was possible to detect ca tionic, anionic and immobile Mn-54 species, and to calculate their ele ctrophoretic mobilities. The interaction of Mn-54 with humic substance s (HS) in a freshwater system is demonstrated by the formation of an e lectrophoretically immobile zone and the formation of the cationic for ms of Mn-54 having smaller electrophoretic mobilities than cationic fo rms of Mn-54 in a freshwater system without HS added. The amount of ca tionic forms decreases in the presence of HS. This effect is enhanced with an increase in HS concentration in the range 5-100 mg l(-1) and i n an increase in pH from 9.5 to 10.5. The addition of HAB up to 100 mg l(-1) and the increase of pH from 7.9 to 9.0 in diluted seawater syst ems do not cause significant changes of cationic electrophoretic mobil ities of Mn-54, nor the formation of an electrophoretically immobile f orm of Mn-54. (C) 1997 Elsevier Science Limited.