SITE INFORMATION AND CORRESPONDENCE

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Stantec Interim Remedial Action Plan Former ARCO Service Station No. 443 July 10, 2008 2.0 Proposed Scope of Work The proposed scope of work for this work plan includes the installation of four monitoring wells and perform monthly vacuum truck interim response activities. Details for the activities associated with the completion of the scope of work are provided below. 2.1 Site Health and Safety Plan As required by the Occupational Health and Safety Administration (OSHA) "Hazardous Waste Operations and Emergency Response' guidelines (29 CFR 1910.120) and by California Occupational Health and Safety Administration (Cal-OSHA) "Hazardous Waste Operations and Emergency Response" guidelines (CCR Title 8, Section 5192), the contractor will prepare a site specific Health and Safety Plan (HASP). At a minimum, the HASP will define the proposed subsurface investigation activities, describe physical and chemical hazards that may be associated with the work, provide a map to the nearest emergency medical facility, and include material safety data sheets for any hazardous chemicals that will be used or produced during the work. A copy of the HASP will be available onsite at all times during field work. The field staff and contractors performing field activities will review the HASP prior to beginning field operations, as described in this work plan, at the site. 2.2 Permitting Prior to beginning field work, all necessary permits will be obtained. 2.3 Soil Boring Advancement, Soil Sampling, and Monitoring Well Installation To get a more accurate depiction of conditions beneath the site, the installation of four monitoring wells (MW-5 through MW-8) are proposed at the approximate locations shown on Figure 2. The locations of the proposed wells may require field modification due to unforeseen conditions such as obstructions or space constraints to accommodate drilling equipment placement, etc. However, final proposed locations of all wells, if different than shown herein, will be approved by the SJC/EHD prior to initiating field activities. Stratus staff will supervise the drilling and installation of MW-5 through MW-8 at the locations shown on Figure 2. Soil borings will be advanced to approximately 65 ft bgs for MW-5 through MW-7 and 120 ft bgs for MW-8 using a drill-rig equipped with eight-inch diameter, continuous flight, hollow-stem augers. In an effort to minimize vertical migration, MW- 8 will be cased to 95 ft. During advancement, soil samples will be collected at five-foot intervals using a steel split-spoon sampler driven approximately 24 inches using a 140-pound hammer that is dropped 30 inches. The sampler will be lined with six-inch long by two-inch diameter brass or steel tubes. An attending Stratus geologist will log cuttings and sample in accordance with American Society for Testing and Materials D-2488—Standard Practice for Description and Identification of Soils (Visual-Manual Procedure) under the direction of a State of California Professional Geologist or Professional Engineer. Soil cores will be screened in the field for the presence of volatile organic compounds using a photo ionization detector (PID). All down-hole 3 443 IRAP.doc