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r 19 October 2012 AGE-NC Project No. 97-0312 Page 9 of 22 Chemical properties and health risk data for 26 chemicals of possible concern are supplied in the program including benzene, toluene, ethylbenzene and xylenes. Total petroleum hydrocarbons (TPH) is not an individual chemical with definite properties, and therefore is not included on the list of chemical choices. Output can be displayed in several ways, too including annual reports, tables and graphs. WW 3.1.2 Site Specific Conditions Based on data collected from the site and cross sections generated, two areas of greatest concern were identified and examined; the former UST cluster location and the area near monitoring well MW-5. Cross sections of the impacted soil plume were depicted in the AGE prepared Quarterly Report-September 1999, dated 29 December 1999. Both areas were divided into four layers based on hydrocarbon concentrations. The soil profile beneath the site is reasonably vertically homogeneous, consisting primarily of silt. `r Mass calculations for the first area were based on data from samples collected in the UST cluster excavation, soil stockpile samples and boring B14. The top layer consists of the stockpiled soil returned to the excavation and non-impacted fill dirt from surface grade to 4.6 meters (15 feet); the second layer is impacted soil from 4.6 to 6.7 meters (15 to 22 feet); the third layer is slightly-impacted soil from 6.7 to 10.4 meters(22 to 34 feet); and the fourth layer is the non-impacted soil from 10.4 to 15.0 meters (34 to 49 feet). The area of impacted soil was arbitrarily defined as 5 meters by 5 meters with all mass calculations based on this area. w The mass of contaminants in the upper-most section was based upon the average concentrations of soil stockpile samples for the soil placed back into the excavation. Mass tow calculations for the second layer were based on the highest concentrations detected in the UST excavation and boring B14 samples. BTEX compounds were not detected in boring B14 below a depth of 20 feet. Therefore, the detection limit of 0.005 mg/kg was used to r.., calculate a maximum mass of contaminants in the third and fourth layers. Calculations for the second area were based on data from boring MW-5. The area was divided into four layers; from surface grade to 7.0 meters(23 feet), from 7.0 to 11.3 meters (23 to 37 feet), from 11.3 to 14.3 meters (37 to 47 feet), and from 14.3 to 15.3 meters (47 to 50 feet). The area of impacted soil was arbitrarily defined as 5 meters by 5 meters with .. all mass calculations based on this area. For each layer, the maximum concentration detected in soil samples within that layer was assumed for the entire layer. • General site stratigraphy was defined from numerous soil borings advanced at the site. Permeability values were estimated from general soil characteristics. Climatic parameters were estimated from historical local weather conditions.An average hydraulic gradientwas r Advanced GeoEnvironmental,Inc.