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H. INVESTIGATION PLAN 2.01 Site Investigation Objective The objective of the work proposed here is to more-fully delineate the extent of petroleum hydrocarbon impact in the vadose zone. To accomplish the vadose zone investigation, we will collect soil and groundwater samples near the for-ner tank location and to the north of the former tank. In particular, the site investigation will address questions about the quality of backfill in the 10,000 gallon UST excavation. This can also resolve our concern about the possibility of recontamination of the lower portion of the backfill due to LNAPL smearing caused by fluctuating groundwater levels. The site investigation will also address EIID's concern that the northern extent of contamination has not been adequately delineated. 2.02 Field Activities This supplemental site investigation will use a truck-mounted, direct-push sampling rig for collection of soil samples. Because of the shallow nature of the contamination and the relatively small lateral extent, we envision a one-day sampling effort to collect soil samples f-orn the 10 locations shown on Figure 3. Conditions permitting, two borings within the footprint of the former tank excavation will be advanced to 35 feet to collect current data on the deep contamination near MW-2 (Figure 3). The remaining borings will be advanced to approximately 20 feet. Up to 30 soil samples will be submitted to a state-certified laboratory for analysis. Hydropunch groundwater samples will be collected from the two deep borings. All work, where applicable, will be conducted in accordance with EIID guidelines. Actual sample locations maybe adjusted in the field to accommodate drilling obstructions, accessibility problems or other constraints at the site. The following sections describe the field activities to take place during this investigation. Activities include: health and safety considerations; permitting, monitoring well installation, soil and groundwater sampling,laboratory analysis of soil and ground water samples, quality assurance/quality control (QA/Q(,); decontamination of field equipment; and management of' soil residuals. A. Health and Safety Considerations Health and safety considerations during field activities will be outlined in a site-specific Health and Safety Plan. All field personnel will be given time to review and sign the plan prior to commencement of any field activities. In addition, a health and safety meeting will be conducted at the start of each day during drilling activities to identify and address any concerns of the field personnel. B. Permitting ContiGroup will obtain the necessary permits from EHD for drilling soil borings prior to conducting any field work. In addition, ContiGroup will provide EHD with 48 hours notice prior to drilling. 3