Snow covers many parts of the earth's surface for a portion of the year; and in areas that experience seasonal snowmelt, the runoff plays an important role in recharging surface water and groundwater systems. Snowpacks, however, accumulate manmade and "natural" pollutants. This accumulated material will enter aquatic systems during spring melt. The chemical load does not enter the aquatic systems gradually; a substantial fraction of the chemical load is released from the base of the pack in the initial melt period. The result is some watersheds receive significant amounts of acids, trace metals, and other contaminants in a short period of time. It is expected that the results of this work will contribute to the understanding of snowpack processes, in particular the scavenging of gases and the formation of acidity in the snowpack. The purpose of the proposed work is to gain insight into the physical and chemical processes involved in the formation of acidity in snowpack. The experiments are designed to investigate the incorporation of sulfur dioxide and the oxidation/reduction reactions that can contribute to the acidity of snow. The amount of gas sorbed on the snow as a function of time and the oxidation products in the snow will be modeled to gain insight as to the chemical and physical mechanisms.
