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I ' 08 November 2005 . AGE-NC Project No. 98-0481 ' Page 6 of 8 4.1. EXTENT OF HYDROCARBON-IMPACTED SOIL ' Based on soil sample analytical results,relatively Iow levels of petroleum hydrocarbons were report directly beneath the former dispensers and associated product piping. Results from soil samples fcollected during the UST removal activities indicated detections of petroleum hydrocarbons at 4 and 8 feet bsg in the former dispenser area. Subsequently,results from soil boring B-I g,located between the two former dispenser locations, indicate that petroleum impacts from the dispensers did not ' extend to a depth of 9.5 feet bsg. No indications of hydrocarbon impact to soil were observed or reported for soils encountered in soil borings SB-1, SB-3, SB-4, or B-1, located around the former fuel dispenser island. However, the rupture of the active gasoline product line during the drilling of boring SB-2 resulted in reported detections of petroleum hydrocarbons extending to 7.5 feet bsg at the HA-1 location. The extent of petroleum hydrocarbon impact directly below the spill site was ' not assessed; however, soil samples subsequently collected from borings (SB-3 and SB-4), located within 8 and 12 feet of the spill site, had no reported detections of petroleum hydrocarbons, which indicates that impacts did not migrate significantly vertically or lateral from the spill site. As shown on Figures 6, 7, and 8, the extent of petroleum hydrocarbon-impacts to soil do not appear to extent beyond the immediate vicinity of the fuel dispenser island. . The amount of TPH-g in soil,based on the estimated lateral and vertical extent of the TPH-g plume (Figures 4 and 7), was calculated to be approximately 6.28 lbs, or approximately 1.0 gallon (Appendix Q. The amount of gasoline released from the line rupture was estimated to be between 3.7 and 6.9 gallons;however,a portion of that would have evaporated during the several days needed to repair the product line and re-pave the area. ' 4.2. EXTENT OF HYDROCARBON-IMPACTED GROUND WATER ' Ground water was encountered at approximately 59 feet bsg.Laboratory analysis of the grab ground water sample (SB4-H20) collected from boring SB-4, located approximately 12 feet northwest of the former dispenser island and spill site reported no detections of petroleum hydrocarbons. As shown on Figure 4, an apparently thick layer of fine-grained material exists below the initial 25 feet of interbedded silt and sands. Therefore, it appears that the relatively thick layer of fine-grained material is a sufficient barrier preventing the vertical migration of petroleum hydrocarbons to ground water beneath the dispenser location. ' According to the findings of an AGE sensitive receptor survey(Appendix A), conducted between October and November 2005, the closest potential receptor is a municipal well (Identified as municipal well#1) located at the end of Roosevelt Street, approximately 1,700 feet southeast from the site. Due to the significant distance between the site and the municipal well, the minor petroleum-hydrocarbon impacts to soil, and lack of impact to ground water, there does not appear • to be a significant concern regarding the location of the well.No other receptors noted in the survey Advanced GeoEnvironmental,Inc..