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2.3 Monitoring Well Installation In 1987, LSD contracted with Groundwater Technology, Inc. {GTI} and initiated an assessment of the impacted soil and groundwater. Between 1987 and 1992, 10 groundwater monitoring wells were installed at the site. No petroleum hydrocarbons were detected in soil samples collected during the installation of the monitoring wells; only very low organic vapor readings were detected in samples from MW-6 and MW-7. However, no investigation of soil in the vicinity of the tank pit or west of MW-2 has been undertaken. 2.4 Groundwater Monitoring i..- Groundwater samples have been collected at the site on seven occasions since June 1987. Petroleum hydrocarbons were detected in the groundwater in the_vicinity of the former dispensers. GTI has delineated the groundwater plunae as having a roughly elliptical shape, ` extending from MW-2 at the south to near MW-5 at the north. The center of the plume has apparently remained near MW-6 (GTI report dated March 3, 1992). The depth to groundwater at the site was approximately 8 feet below surface grade during the last sampling event (January 1992). Groundwater flow direction at the site has. historically been to the north at a gradient of appro 'mately 0.01 ft/ft. �-; Since 1992, representatives of LSD have been collecting and reporting groundwater depths t in all wells intermittently. The most recent report was dated March 29, 1994; groundwater depths ranged from approximately 7.9 feet to 8.5 feet. 4.0 DRILLING AND SAMPLING r, In a letter dated July 1991, the PHS/EHD states that 'current data shows the contaminated groundwater has moved and more site investigation is needed to establish the extent of contamination". No monitoring well data is available northwest of MW-2 and southwest of ' MW-9. GeoAudit proposes to install one additional monitoring well in this area to provide groundwater plume data west of the plume estimated by GTI. The proposed location of the monitoring well is depicted on Figure 2. Hydrocarbon-impacted soil at the site appears to be inimal. No petroleum hydrocarbons were detected in soil samples collected during the installation of any of the monitoring wells; only very low organic vapor readings were detected in samples from MW-6 and MW-7. However, no investigation of soil in the vicinity of the gasoline UST or southwest of MW-2 has been undertaken. GeoAudit proposes to drill one oring near the former UST area; the proposed location of the soil boring is illustrated on Figure 2. Section 5.0 lists the procedures to be performed to complete the drilling and sampling. G-1.3"I A."Be,�,I.. IODWsaA"UFRSV1 A WO 2 I�