RELATION BETWEEN TOTAL MERCURY AND SOME V ARIABLES IN 3 SUBSYSTEMS OFTHE PARANA RIVER FLOODPLAIN

Total mercury concentrations were measured bimonthly between April 199 4 and February 1995. Samples were made in three subsystems of the Para na river's floodplain, between Parana and Mato Grosso do Sul States, B razil. The total mercury content was determined by H2SO4/KMnO4 digesti on, SnCl2 reduction, and vapour generation method analysis (CGCH 900), adapted to Atomic Absorption Spectrometer (CGAA 7000 ABC). Mean mercu ry concentration in composite water varied from .64 to .78 ng.ml(-1) i n these subsystems. Potassium explained 59% of the variability of wate r mercury in Parana/Cortado, while pH explained 20% and maximum depth explained 37% in Baia/Guarana and in Ivinhema/Patos, respectively. Som e mercury values in April and August exceed criteria for issuance of w ater consumption advisories (>.002 mu g. ml(-1)).