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Abstract Questions concerning the transport and fate of contaminants in the environment have typically been limited to single compounds. However, the greatest danger to water resources is most often posed by sites releasing complex mixtures containing many, even hundreds, of hazardous chemicals. Hazardous waste disposal facilities, chemical plants, oil refineries, etc., typically produce complex waste streams which may contact ground water or surface waters. This progress report presents results of a study on movement through ground and surface water of a complex mixture of organic compounds emanating from a wood-treatment facility located adjacent to the Laramie River in Laramie, Wyoming. This study, initiated in FY 1983, is continuing with USDI funding for a second year, through summer 1985.
The objectives of the study are to (1) initiate a literature review on contaminant transport models and develop a conceptual model of contaminant transport at the Laramie River site; (2) conduct laboratory (soil column) and field experiments to investigate oil/water emulsion migration through porous media; and (3) begin a field study analyzing contaminant fate in sediments downstream from the wood-treating facility. A fourth objective, to supply the Wyoming Department of Environmental Quality (DEQ) with a summarization of contaminant transport models, was deferred to FY 84 based on requests from DEQ officials to incorporate the Year 2 study and submit a single, final report.
Currently, mathematical models are not readily available to simulate the transport and fate of complex mixtures of organic compounds. This is especially true when these contaminants are in high concentrations producing a multi-phase solution. But a conceptual model summarizing laboratory and site observations shows: (1) subsurface transport of contaminants in oil, oil/water emulsions, and groundwater; and (2) riverine transport of contaminants in water, sorbed to sediments, and as oil globules.
Experiments with glass columns packed with a uniform material (1 mm glass beads, sand, or gravel) indicates that in even the most homogenous, isotropic matrix, oil/water mixtures cannot be expected to flow in a uniform manner. Creosote sludges and oils break up into globules and stringers with no uniform front of contamination. Data from a field study using mini-piezometers in the Laramie River adjacent to the site confirm this observation.
Chemical analyses of sediments and fish, as well as field observations indicating oily droplets moving along the river bed, clearly establish contamination of the Laramie River resulting from offsite migration of creosote from the wood-treating facility.
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