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In January 1991, Associated Sods Analysis (ASA) supervised the drilling of three soil borings and the installation of three monitoring wells (MW-1, MW-2 and MW-3) each to a depth of 25 feet below grade Detectable concentrations of petroleum hydrocarbons were present in soil and ground water samples collected from all monitoring wells. Detailed results are presented in the report by ASA titled "Site Assessment Study for Petroleum Constituents in the Soil and Ground Water at HMC Location No 100878," dated April 1, 1991 In June 1992, Tank Protect Engineering (TPE) supervised the drilling of three soil borings and the installation of three monitoring wells (MW-4, MW-5 and MW-6) each to a depth of 31.5 feet below grade Detectable concentrations of petroleum hydrocarbons were present only in soil and ground water samples collected from monitoring well MW-5 Depth to ground water beneath the site is approximately 20 feet below grade, and flows towards the north with a gradient of approximately 0 002 feet/feet Detailed results are presented in the Preliminary Site Assessment Report by TPE, dated August 24, 1992 WORK ACTIVITIES: Permit and drill two additional soil borings, and install monitoring wells MW-7 and MW-8) in locations shown on the attached site plan (Figure 2) The purpose of these borings and well installations is to determine the lateral extent of the fuel constituents detected during the preliminary site assessment. This effort is necessary to satisfy criteria established in the LUFT manual for the determination of concentrations of hydrocarbons that are acceptable to leave in place without remediation The soil borings will be drilled to approximately 30 feet below ground surface Soil samples from each boring will be collected at five foot intervals Soil samples will be analyzed for concentrations of contaminants detected during preliminary site assessment (gasoline constituents) A two-inch diameter monitoring wells will be installed in each soil boring The new monitoring wells will be surveyed relative to an existing benchmark and developed through a combination of surging and bailing of at least ten well volumes Ground water samples will be collected from each of the new and existing monitoring wells during this phase of investigation I IL KEY SAFETY PERSONNEL AND RESPONSIBILITIES All personnel working for HETI at the lob site are responsible for project safety Specific individual responsibilities are listed below: Project Manager' 1 1 I 1 i 1 ' I , The Project Manager is, responsible for preparation of this SSP .He/she,has the authority, to' provide for the,auditing of compliance with the p'rovision's of this 1 � SSP,,suspend or (modify w ; a orks practices.' to'report to 'the ,Regional Manager I t 1 1 V 7-237 2 11/22/93 i t 1 � I