Microstructural Alteration of Hydrocarbon Contaminated Permafrost Affected Soils at the Caribou - Poker Creeks CREEL Research Watershed: Implications for Subsurface Transport

• Main Authors: White, Thomas L., Williams, P. J., Rees, W. G., Marchand, Yvette
• Other Authors: SCOTT POLAR RESEARCH INST CAMBRIDGE (UNITED KINGDOM)
• Format: Text
• Language: English
• Published: 2000
• Subjects: Snow; Ice and Permafrost; Solid Wastes Pollution and Control; *MICROSTRUCTURE; *HYDROCARBONS; *CONTAMINATION; *PERMAFROST; EXPERIMENTAL DATA; LAYERS; THERMODYNAMICS; ALASKA; POROSITY; CLAY MINERALS; SITE INVESTIGATIONS; REMOTE DETECTION; CONCENTRATION(CHEMISTRY); OIL SPILLS; SILT; SATELLITE IMAGERY; UNITED KINGDOM; FOREIGN REPORTS; Caribou-Poker Creeks Research Watershed; Ice; permafrost; Alaska
• Online Access: http://www.dtic.mil/docs/citations/ADA378625; http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA378625

The thermodynamic conditions within the seasonally frozen active layer overlying permafrost in the Caribou-Poker Creeks Research Watershed in Alaska are such that there is continuing translocation of water and ice, and the displacement of soil particles. The introduction of immiscible hydrocarbon compounds from two large scale winter and summer experimental crude oil spills into this dynamic porous medium results in microstructural changes that take place as a function of cryogenic process and contaminant concentration. Optical and scanning electron microscope observations reveal evidence of changes in soil morphology. Reorganisation of silt and clay size minerals and organic particles has resulted in changes in aggregation and interaggregate porosity in the histic pergelic cryaquest. The degree of interaggregate porosity increases as a function of hydrocarbon concentration, specifically volatiles and as a function of the soil profile. Hydrocarbon concentrations were observed to decrease as a function of depth in the O1, A1 and C1 horizons for all the sites, including the selected control site situated between the winter and summer experimental oil spills. The modifications of the microstructure change macroscopic properties (thermal, hydraulic, and mechanical), and this leads to modifications in terrain which become more marked over years. Remote sensing techniques will be important in the prediction and verification of contaminant movement.