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February 13,_1998 - Page 4 time. The highest concentrations of hydrocarbons in groundwater were recently reported in Well MW-7, southeast(downgradient) of the site, in which TPH-g and benzene were reported at 6,300 and 260 ppb, respectively. Nondetect concentrations of hydrocarbons in Well MW-8 suggest that the hydrocarbon plume has been laterally defined downgradient of the former USTs. The below proposed scope of work will confirm whether hydrocarbons are defined in the deeper impacted zones. During the most recent(fourth quarter 1997) sampling, MtBE and other oxygenates by EPA Method 8260 and methanol by EPA 8015 were reported to be nondetectable (Blaine, January 29, 1998). PROPOSED SCOPE OF WORK The scope of work proposed for this investigation will include the drilling and sampling of three offsite borings and one onsite boring (Figure 2). Discrete soil and groundwater samples will be collected from each of the borings to further characterize the hydrogeology in the site area and to further evaluate the lateral and vertical extent of hydrocarbons in soil and groundwater. Prior to performing field work at the site, SECOR will prepare a Site-Specific Health and Safety Plan required by the Occupational Health and Safety Administration (OSHA) Standard"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 Site-Specific Health and Safety Plan will be reviewed by the project manager, field staff and contractors before beginning field operations at the site. Applicable permits for soil borings will be obtained from the PHS/EHD prior to drilling. Additionally, prior to drilling soil borings within the City right-of-way, appropriate encroachment permits will need to be secured. The specific scope of work is discussed below: • Borings. Four proposed borings (one onsite and three offsite) will be drilled at the general locations shown on Figure 2. It should be noted that the area beneath the Highway 4 overpass is inaccessible to auger drill rigs able to perform the proposed scope of work, and therefore, as we discussed in our January 29, 1998 meeting,none of the borings will be located in that area. The borings will be continuously sampled to total depth. In addition, three to four depth discrete soil and groundwater samples-will be collected from the borings within saturated c6 rser-grained units in an effort to evaluate the presence of hydrocarbons in soil and '' groundwater at depth. Based on existing site information,primarily r 7G007-013-01/workplan V-