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Contaminant migration through the permafrost active layer, Mackenzie Delta area, Northwest Territories, Canada

Published online by Cambridge University Press:  27 October 2009

Larry D. Dyke
Larry D. Dyke
Affiliation:
Geological Survey of Canada, 601 Booth Street, Ottawa, Ontario K1A 0E8, Canada
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Abstract

Buried pits (sumps), used for the disposal of drilling muds in the Mackenzie Delta area of Arctic Canada, provide an opportunity for assessing the effectiveness of ice-bonded permafrost sediments as a containment for industrial wastes. Potassium chloride (KCI) added to drilling muds as a freezing-point depressant provides a suitable tracer, because it is easily identified and natural concentrations in sediment pore water are typically low (less than 0.02 g l−1; potassium). Muds with KCI concentrations of up to 10% by weight (100 g l−1) have been used. In the vicinity of sumps, potassium is found at elevated concentrations of up to several g l−1 in the seasonal thaw layer (active layer) at distances well beyond what would be expected from diffusive transport alone. Within the level alluvial silts of the modern Mackenzie Delta, KCI has moved up to 50 m laterally from sump edges. On surrounding tundra uplands, KCI has migrated several hundred metres downslope within the active layer.

Although ice-rich permafrost sediments appear to form an effective barrier against downward movement of solutes, thawing ice lenses and veins within the active layer greatly increase the lateral hydraulic conductivity in this zone during the thaw season. Compared with unfrozen silty sediments, the large pores left by thawed ice fabric in the same sediment after a freeze–thaw cycle have been shown to increase the hydraulic conductivity up to four orders of magnitude. This phenomenon is probably common in thawing, ice-rich sediments and presumably favours accelerated downhill movement of solutes. On level ground, it is anticipated that KCI movement is promoted by fluid densities approaching that of sea water. Laboratory experiments with thawed sand and both unfrozen and thawing Mackenzie Delta silt confirm the existence of density-driven solute movement and the importance of thawing ice fabric in promoting solute movement. The thawed ice fabric of active-layer sediments and the presence of a frost table promote lateral movement of fluids when a density or elevation gradient is present. These tendencies widen the area potentially affected by contaminant migration from abandoned waste sites and they may also promote the movement of contaminants that escape from future containments.

Type
Articles
Information
Polar Record , Volume 37 , Issue 202 , July 2001 , pp. 215 - 228
Copyright
Copyright © Cambridge University Press 2001

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References

Adams, B. 1998. Contaminant movement in frost-affected soils. Unpublished MSc thesis. Ottawa: Department of Geography, Carleton University.Google Scholar
Biggar, K. (editor). 1999. Assessment and remediation of contaminated sites in Arctic and cold climates. Edmonton: Department of Civil and Environmental Engineering, University of Alberta.Google Scholar
Burgess, M. M., and Smith, S.L. 2000. Shallow ground temperatures in the Mackenzie valley. In: Dyke, L. D., and Brooks, G. R. (editors). The physical environment of the Mackenzie valley: a baseline for the assessment of environmental change. Geological Survey of Canada Bulletin 547: 90–105.Google Scholar
Burt, T. P. 1974. A study of hydraulic conductivity of frozen soils. Unpublished MSc thesis. Ottawa: Department of Geography, Carleton University.Google Scholar
Chamberlain, E. J., Erickson, A. E., and Benson, C. H.. 1997. Frost resistance of cover and liner materials for landfills and hazardous waste sites. Hanover, NH: Cold Regions Research and Engineering Laboratory (CRREL Special Report 97–29).Google Scholar
Church, M. A. 1974. Hydrology and permafrost with reference to northern North America. In: Permafrost hydrology. Ottawa: Environment Canada: 7–20.Google Scholar
Domenico, P. A., and Swartz, F. W.. 1990. Physical and chemicalhydrogeology. Toronto: John Wiley and Sons.Google Scholar
Dyke, L. D., and Egginton, P. A.. 1988. Till behavior and its relationship to active layer hydrology, District of Keewatin, Northwest Territories. Canadian Geotechnical Journal 25: 167–172.CrossRefGoogle Scholar
Dyke, L. D., and Egginton, P. A.. 1990. Influence of ice lens fabric on the hydraulic conductivity of thawing soil. Collection Nordicana 54: 137–141.Google Scholar
Hill, P. R., Héquette, A., Ruz, M.-H., and Jenner, K. A.. 1991. Geological investigations of the Canadian Beaufort Sea coast. Ottawa: Geological Survey of Canada (Open File Report 2387).CrossRefGoogle Scholar
Jenner, K. A., and Hill, P. R.. 1991. Sediment transport at the Mackenzie Delta-Beaufort Sea interface. In: Marsh, P., and Ommanney, C. S. L (editors). Mackenzie Delta: environmental interactions and implications of development. Saskatoon: National Hydrology Research Institute: 39–52.Google Scholar
Jensen, J., Adare, K., and Shearer, R. (editors). 1997. Canadian Arctic contaminants assessment report. Ottawa: Indian and Northern Affairs Canada.Google Scholar
Kueper, B. H., and McWhorter, D. B.. 1996. Physics governing the migration of dense non-aqueous phase liquids (DNAPLs) in fractured media. In: Pankow, J. F., and Cherry, J. A. (editors). Dense chlorinated solvents and other DNAPLs in groundwater. Guelph, Ontario: Waterloo Press: 337–353.Google Scholar
Lewkowicz, A. G., and French, H. M.. 1982. The hydrology of small runoff plots in an area of continuous permafrost, Banks Island, NWT. In: French, H. M. (editor). Proceedings of the fourth Canadian permafrost conference. Ottawa: National Research Council of Canada: 163–172.Google Scholar
Li, Y.-H., and Gregory, S.. 1974. Diffusion of ions in sea water and deep-sea sediments. Geochimica et Cosmochimica Acta 38: 703–714Google Scholar
McNeill, J. D. 1980. Electromagnetic terrain conductivity measurement at low induction numbers. Mississauga, Ontario: Geonics Limited (Technical Note TN-6).Google Scholar
Mine Environment Neutral Drainage Program. 1996. Acid mine drainage in permafrost regions: issues, control strategies and research requirements. Ottawa: Mine Environment Neutral Drainage Program, Canada Centre for Mineral and Energy Technology, Natural Resources Canada (MEND Project 1. 61. 2).Google Scholar
Othman, M. A., and Benson, C.H.. 1993. Effect of freezethaw on the hydraulic conductivity and morphology of compacted clay. Canadian Geotechnical Journal 30: 236–246.CrossRefGoogle Scholar
Piteau Engineering. 1988. Groundwater resources protection from drilling waste, Northwest Territories and Yukon. Ottawa: Department of Indian and Northern Affairs, Northern Affairs Program (Environmental Studies 62).Google Scholar
Polar Record. 1999. Papers from the Conference on contaminants in freezing ground, Cambridge, 13–15 July 1997. Polar Record 35 (192): 3–72.CrossRefGoogle Scholar
Smith, D. W., and James, T. D. W.. 1985. Sump studies v: Ecological changes adjacent to sumps at exploratory wellsites in the Mackenzie Delta and northern Yukon. Ottawa: Indian and Northern Affairs Canada, Northern Affairs Program (Environmental Studies 35).Google Scholar
Veillette, J. J., and Thomas, R. D.. 1979. Icings and seepage in frozen glaciofluvial deposits, District of Keewatin, NWT. Canadian Geotechnical Journal 16: 789–797.CrossRefGoogle Scholar
White, T. L. 1999. Environmental conditions of abandoned oil and gas drilling pads and sumps situated in sporatic and continuous permafrost. Yellowknife: unpublished report to the Department of Indian and Northern Affairs.Google Scholar
White, T. L., and Williams, P.J.. 1994. Cryogenic alteration of frost-susceptable soils. In: Frémond, M. (editor). Ground freezing '94: proceedings of the seventh inter national symposium on freezing ground, Nancy, France. Rotterdam: A. A. Balkema: 17–24.Google Scholar
Woo, M.-K., and Steer, P.. 1983. Slope hydrology as influenced by thawing of the active layer, Resolute, NWT. Canadian Journal of Earth Sciences 20: 978–986.CrossRefGoogle Scholar