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I <br />r <br />t- <br />[ <br />F- <br />tF ■ <br />W <br />'^Ar':. <br />i- ■ ■- <br />I* <br />•;;'■ ■■ <br />i_y - <br />:F^' <br />Ffr <br />it, ■ <br />>1^?I" <br />■V' . <br />I <br />; :: <br />¥■ '■ <br />I!'i‘’X< . <br />&If'1^'. <br />i' <br />rk:l> <br />h«^" <br />:h <br />■r <br />‘ '-■ ■ <br />,5. <br />, :•■■ . <br />,*:• <br />t.> <br />92-47.08 <br />The U.S. EPA does not use a single number as the criterion, <br />but rather a range. The U.S. E?A states that its general goal <br />ranges from 10“* to <br />in 10,000,000). <br />-7 (1 excess case of cancer in 10,000 to 1 <br />ECOLOGICAL ASSESSMENT METHODOLOGY <br />The potential ecological effects of the three roadway <br />materials were evaluated by comparing available wildlife <br />contaminant exposure data (Ambient Water Quality Criteria) to the <br />total roadway material contaminants in a theoretical pond located <br />10 meters from the Demonstration Project Site. AWQC are <br />nonenforceable regulatory guidelines that may be used for <br />identifying research-based minimum surface water concentration^ <br />which reflect acute and chronic effects in aquatic species. <br />The evaluation considered contaminant input from roadway <br />surface water runoff and deposition of airborne particulate <br />contaminants into a fixed volume of pond water. The following <br />factors contributed to this evaluation; <br />• Terrestrial food chain evaluation of pond water contaminant <br />concentrations due to deposition of airborne contaminants in <br />the pond watershed for 20 years. <br />• Surface water runoff from the roadway materials removing the <br />total mass of leachable contaminants from the entire roadway <br />material volume (2 in x 750 ft x 24 ft) and depositing it in <br />the pond. <br />• The pond water volume was considered static. In other <br />words, flow through the pond which would dilute contaminant <br />concentrations was no» considered. <br />CONSERVATIVE ASSUMPTIONS USED IN THE RISK ASSESSMENT <br />Air emissions and surface water and groundwater discharges <br />are assumed to concentrate in an area of 10 meters (32.8 feet) <br />surrounding the experimental stretch of road (24 feet x <br />750 feet), as shown in Figure 3. The ecological effects are also <br />assumed to be concentrated in this relatively small area <br />surrounding the experimental stretch of road. <br />Particulate Emissions and Dispersion Calculation <br />Standard methods provided by the U.S. EPA (1985) were <br />employed to estimate particulate emissions (dust) from the <br />roadway materials due to vehicular traffic and weather erosion. <br />1 3 <br />S’