DISSOLVED ORGANIC-MATTER IN CHASCOMUS POND (ARGENTINA) - INFLUENCE OFCALCIUM-CARBONATE ON HUMIC-ACID CONCENTRATION

Water chemistry of the Chascomus Pond (Province of Buenos Aires, Argen tina) was studied during a year characterized by low precipitation. Su persaturation of calcium carbonate up to a calcite saturation index of about 20 in spring and summer was observed, together with a diminutio n of the concentration of dissolved organic matter, in particular humi c substances (HS). These results suggested an adsorption between organ ic matter and calcium carbonate which should influence the growth of c alcium carbonate crystals. A preferential removal of higher molecular weight HS was observed by gel permeation chromatography experiments.