Laserfiche WebLink
i <br /> 26 October 1998 <br /> AGE-NC Project No 97-0249 <br /> Page 4 of 5 <br /> 40 SUMMARY AND CONCLUSIONS <br /> Based upon data collected in August 1998, AGE concludes <br /> • Laboratory and field data collected from soil probe borings suggest laterally extensional <br /> petroleum-impacted soil at least 40 to 55 feet to the south, east and west of the existing UST <br /> area and vertical extension from 5 feet bsg to 20 feet bsg The approximate horizontal and <br /> vertical extent of petroleum-impacted soil is depicted in Figures 5 and 6 and is based on <br /> laboratory data and field evidence noted on boring logs (i e vapor detection, petroleum <br /> odor) <br /> • Laboratory and field data suggest extensive petroleum-impacted soil near the former <br /> southern dispenser island area (P5) at depths between 5 feet bsg and 10 feet bsg with less <br /> intensely petroleum-impacted soil detected at a depth of 15 feet bsg <br /> • Laboratory and field data (P9) suggest that less intensely petroleum-impacted soil extends <br /> at least 45 feet northwest of the existing northwest dispenser island area at a depth of 15 feet <br /> bsg <br /> • The horizontal extent of petroleum hydrocarbon-impacted soil has not been fully delineated <br /> toward the north, south, east and west <br /> • Based on intense petroleum hydrocarbon-impacted ground water preNiously detected near <br /> ithe existing UST and the northwest dispenser island areas (Pi elinunary Ing estigation & <br /> - Evaluation Report, dated 05 November 1997) at depth intervals between 20 feet bsg and 25 <br /> Ifeet bsg, it is possible that ground water has been impacted in the areas of P5 through P9 <br /> 50 RECOMMENDATIONS <br /> Based upon data collected from the site, AGE recommends <br /> • Installation of ground water monitoring wells to provide repeatable ground water sampling <br /> locations, determine site-specific ground water flow direction and gradient and to document <br /> petroleum hydrocarbon concentration trends <br /> • Installation of one ground water monitoring well in close proximity to the on-site domestic <br />' water well to detect any hydrocarbon migration towards the well <br /> • Annual sampling of the domestic water well for analysis of fuel hydrocarbons <br /> Advanced GeoEm troamental Inc <br />