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`..i O • Lateral extent of soil and groundwater impacts immediately east of the former gasoline UST excavation (i.e. Center Street). Drilling and sampling in this area is not possible due to the presence of underground utilities. Soil and groundwater analytical data from monitoring well MW-4 close this data gap further to the east; • Groundwater quality within the flowing sand at approximately 47 feet BGS. The scope of work presented in this document will address this data gap; • Sensitive receptors. A sensitive receptor survey will be conducted as part of future site activities; and • An estimate of mass of TPH-g in soil and groundwater. The written report presenting the results of the investigation outlined in this document will include an estimate of mass of TPH-g in soil and groundwater at the Site. 4.0 PROPOSED SCOPE OF SERVICES The objectives of the proposed scope of services are to further assess the lateral extent of impacts generally north and northwest of the former UST excavation and evaluate groundwater quality within the flowing sand at approximately 47 feet BGS at the Site. Three direct-push borings (C6, C7, and C8)will be drilled at the locations shown on Figure 12. The total depth of each boring will be approximately 55 feet. The locations of the three proposed borings were selected to address gaps in soil and groundwater data north and northwest of the former UST excavation. The proposed locations of the direct-push borings also were selected based on access constraints presented by overhead and underground utilities. After receiving and evaluating the analytical data for soil and groundwater samples collected from the direct-push borings, one groundwater monitoring well (MW-2A)will be installed near the former UST excavation, developed, and sampled to assess the vertical extent of impacts in groundwater, particularly within the saturated sand encountered at approximately 47 feet BGS. Another well (MW-5) will likely be installed north-northwest of the former UST excavation and situated to monitor the lateral extent of the plume, as indicated by the results of the direct- push borings. The two wells will be screened within the flowing sand, which is present below approximately 47 feet BGS. The scope of services will include the following activities: (1)field preparation; (2)direct-push drilling, sampling, and laboratory analysis; (3) drilling, well installation, development, sampling, and laboratory analysis; (4) disposal of investigative-derived waste; and (5) data evaluation and reporting. The details are presented in the following sections. SL-Cents-SCM and Rev.R1 WP 2007.09 13