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- Title
Modelling the fate of non-polar organic chemicals during the meltingof an Arctic snowpack
- Authors
Mackay, Donald; Hoff, John T.; Wania, Frank; Semkin, Ray
- Abstract
Recent advances in the understanding of the interactions between non-polar organic chemicals and frozen water have revealed the immense importance of the ice-air interface and the possibility of quantitatively treating the adsorption process on the ice surface in terms of chemical-specific interfacial partition coefficients and the snow specific surface area. A simple fugacity-based chemical fate model is usedto describe quantitatively the behaviour of selected non-polar organic contaminants during snowpack melting, namely atmosphere-snow exchange, redistribution within the snowpack and draining with meltwater. The simulations are evaluated using field data on snowpack and meltwater concentrations of these chemicals measured in a small watershed in the Canadian Arctic during the melting period of 1993. The model reproduced the observed preferential elution of hexachlorocyclohexanes in the first meltwater fractions, and the relative retention of polychlorinated biphenyls within the snowpack. The model calculations indicate that the specific surface area of the ice crystals and the air-ice and air-water partition coefficients of the chemical are key parameters controlling the extent and timing of chemical loss with the meltwater. For particle-sorptive substances, the fate of particles during snowmelt must also be considered. Uncertainty in describing interfacial partitioning and the behaviour of particles during melting presently limits the capabilities of models to simulate and ultimately predict meltwater concentrations of non-polar organic contaminants.
- Subjects
HYDROLOGY; MATHEMATICAL models; PESTICIDES
- Publication
Hydrological Processes, 1999, Vol 13, Issue 14/15, p2245
- ISSN
0885-6087
- Publication type
Article