Title : Hydrocarbon Transport Type : Antarctic EAM NSF Org: OD / OPP Date : December 04, 1991 File : opp93039 DIVISION OF POLAR PROGRAMS OFFICE OF THE ENVIRONMENT 202/357-7766 MEMORANDUM Date: December 4, 1991 From: Environmental Officer, DPP Subject: Environmental Action Memorandum (Information Item - Study on Hydrocarbon Transport in Polar Soils) To: Files (Environment - S.7) (Hazardous Wastes - S.7.1) Petroleum products represent the most likely and most significant potential contaminants in antarctic environments. Spills of these products from ships have impacted antarctic marine environments. Storage, transport, and use of these products in line with antarctic operations have the potential to contaminate antarctic marine, freshwater, and terrestrial environments. Increasing understanding of the transport, fate, and effects of these potential contaminants is a goal of the U.S. Antarctic Program. Recent investigations by Dr. Mark A. Tumeo (University of Alaska, Fairbanks) are providing useful information on the nature of hydrocarbon contaminant transport in polar groundwater and soils. This Environmental Action Memorandum reports some of Dr. Tumeo's findings presented at the 12th Annual Hazardous Materials Control Research Conference. ================================================================= ABSTRACT Hydrocarbon Contaminant Transport in Systems At or Near Freezing Mark A. Tumeo, Ph.D., P.E. Environmental Technology Laboratory University of Alaska Fairbanks, AK 99775-0660 907/474-6090 [Presented at the 12th Annual Hazardous Materials Control Research Conference Washington Sheraton Hotel Washington, DC December 3-5, 1991] Pollution of groundwater by hydrocarbon contaminants has recently gained national attention as contamination is being discovered across the country. Many water supplies are contaminated with low concentrations that are not easily detected. However the presence -2- of hydrocarbons in groundwater, even in low concentrations, may present a possible health hazard. Little is known about the move- ment of hydrocarbons in groundwater at or near freezing. Wide variations in soil and groundwater temperatures are common in the Arctic and Antarctic and can be expected in artificial freezing situations. Under freezing or near--freezing conditions, tempera- ture induced changes in fluid viscosity and the exclusion and immobilization of hydrocarbon contaminants can have dramatic impacts on field-scale transport. This paper reports on research at the University of Alaska Fairbanks to explore the fate of hydrocarbon contaminants in groundwater at or near freezing. The project addresses some of the fundamental questions which surround the analysis and prediction of hydrocarbon contamination movement in cold regions. The informa- tion gained through this research is applicable in cold regions outside Alaska and the Arctic where groundwater systems may undergo periodic freezing, and may also be of extreme importance in artifi- cial freezing scenarios such as those currently being investigated by the EPA as a method of contaminant containment. Bench scale studies were conducted using a "constant-head groundwater flow chamber" and natural soil. Freezing fronts were induced from the soil surface downward using cooled Freon circulat- ed through 'freezer pads' placed on the surface of the soil. Slug inputs of various contaminants, including hydrocarbons, were intro- duced to the system using a syringe and contaminant movement with time monitored under freezing and non-freezing conditions. Results of the bench scale studies were used to further develop a computer model (GWFREEZE) that incorporates the processes of temperature induced changes in fluid viscosity, exclusion and immobilization into a two-dimensional transport equation for saturated porous media under steady flow conditions. Details of the model have been published previously in Groundwater (Zukowski and Tumeo, 1991, Vol. 29(1), pp 21-25). ================================================================= Sidney Draggan cc: Environmental Engineer, DPP Environmentalist, ASA