AMMONIUM, ALKALINE AND ALKALINE-EARTH ELEMENT DETERMINATION IN ANTARCTIC LAKE WATERS, FLOWING MELT WATERS AND SNOW

Concentrations of lithium, sodium, potassium, magnesium and calcium we re measured by ion-chromatography in samples collected in different si tes during the 1989/90 Italian expedition in Antarctica. Sea waters, l ake waters, flowing melt waters and snow were considered. In addition ammonium was determined in all the samples whenever the chromatographi c separation of adjacent sodium and ammonium peaks was feasible. For e ach element the observed intervals of concentrations (shown in bracket s) were: Snow (concentrations in muM units): Li(not detectable);Na(3-2 2);NH4(0.3-13); K(0.2-1); Mg(0.4-2); Ca(0.3-1). Lake and melt waters ( in mM units): ;Na(0.1-6);K(0.01-0.3);Mg(0.01-0.6);Ca(0.006-0.6). The l owest concentrations were found in melt waters. Sea waters (in mM unit s): Li([22-27]X10(-3)); Na(418-472); K(8.7-10); Mg(49-56); Ca(9.2-11). The above data represent the intervals of variability due to the non- homogeneity of composition among the sampling sites; for sea water, th ey include the water column depth effect. Correlations were searched f or between relative concentrations of the analytes for the different n atures of the samples in order to distinguish the origin of salt conte nt both in snow and meltwater from marine aerosols and other environme ntal sources.