Structural Aspects of Aquatic Humic Substances in a Patagonic River

SCAPINI, M.C.; CONZONNO, V.; BALZARETTI, V.; FERNÁNDEZ CIRELLI, A.

San Pedro

Congreso; XII International Meeting of International Humic Substances Society; 2004

International Humic Substances Society

Chubut River flows across the semiarid patagonic region. Florentino Ameghino Reservoir was built in this river for hydroelectric generation, water public supply (Dolavon, Gaiman, Trelew, Rawson and Madryn cities) and agricultural purposes in its valley. The River finally reaches the Atlantic Ocean in a way of estuarine environment. Some structural aspects of present Aquatic Humic Substances (HS) in the Chubut River were investigated, as a first step of a more comprehensive project being carried out for evaluating their structural characteristics and role in this system. A preliminary study on the HS of the estuary was conducted (1) earlier, but no systematic work in this river has been carried out up to date. HS are polymeric organic compounds of aromatic nature, having a great content of carboxylic acid groups and high molecular weight (2). They are the major constituents of dissolved organic matter and cause serious environmental effects concerning with the river utilization. HS interfere with water treatment for public supply, bringing about the formation of trihalomethanes compounds, stability on colloids and the affectation of bacteria and algae growth. These properties have to be with the main problem detected in public water treatment plants, consisting of filters plugging by alluviums and diatoms blooms. It has been reported cases of paralytic shellfish poisoning in the estuary. Also this fact promotes the study of HS in view of their relation with the growth of dinoflagellates.            The HS properties are dependent on their structures, origin and participation in physicochemical and biological processes.