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92-47.08 <br />• Individuals live within 33 feet of the road their entire <br />life <br />• Individuals consume their daily liquid consumptions only of <br />the study area (within 33 feet from Demonstration Project) <br />• Individual consume food products grown and raised within <br />33 feet of the Demonstration Project. <br />• Leachates entering the groundwater are not what rainwater or <br />stormwater would leach from the road materials, but rather <br />leachates produced by the TCLP extraction procedure. It is <br />well documented that the TCLP extraction procedure, which <br />uses acetic acid, is much more aggressive than rain or <br />stormwater. <br />Food Chain Modeling of Contaminants <br />'ffi: <br />W: <br />ifct' <br />y- •' <br />I- <br />■ <br />;|k- <br />r <br />s.. <br />€'k <br />1^I: <br />.pi- <br />• <br />1^' ■ <br />The Terrestrial Food Chain Model (TFCM) requires various <br />input data to estimate the accumulation of contaminants in plant <br />animal and fish tissues, and calculate a human daily exposure <br />based on consumption. If site specific or regional Minnesota <br />data were not available, model input values were chosen which <br />tended to overestimate accumulation and exposure. Some of these <br />conservative assumptions include: <br />• All environmental matrices (plant, animal, fish, human <br />tissues) considered by the model were assumed to be located <br />at the point of highest air concentration and deposition of <br />contaminants from the source (10 meters). This means that <br />all crops, animal feed, animals, the pond containing fish, <br />and human receptors were simultaneously located at the same <br />maximum contaminant concentration point. <br />• Contaminant air concentrations and deposition rates used <br />were based on total suspended particulate (TSP) <br />concentrations rather than the lower concentrations for the <br />respirable PM-IO particle sizes. <br />• A total deposition time period of 20 years was considered. <br />Food chain trophic levels are exposed to environmental <br />matrices containing constituent concentrations equivalent to <br />20 years of accumulation (deposition, uptake, retention). <br />• Input parameters affecting the final concentrations of <br />contaminants in environmental matrices were consistent for <br />the three scenarios considered in the modeling of each <br />constituent.