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k Chevron Products Company 2 Fortner Chevron Service Station 99-8632 Tracy, CA November 3, 1998 - In May 1995, wells MW- 1 through MW-4 were installed at the site (Figure 2). Maximum concentrations of TPH-g and benzene in wet soil were reported in the area of the former pump islands in boring MW-3 at 7,600 mg/kg (@ 6. 5 ') and 24 mg/kg (@ 6. 5 '), respectively. Groundwater monitoring has been performed quarterly since September 1995 . Third quarter 1998 results indicated concentrations of TPH-g, benzene, TPH-d, and MtBE up to 6,300 parts per billion (ppb), 680 ppb, 2,000 ppb, and 1 ,400 ppb, respectively. Analytical results from downgradient well MW- 1 indicated concentrations of 160 ppb TPH-g, 4 ppb benzene, 88 ppb TPH-d, and 59 ppb MtBE (Blaine, 1998) . Groundwater flow has been reported consistently to the northwest at gradients ranging from 0. 04 to 0.02 feet/feet, PROPOSED SCOPE OF WORK The scope of work for this site assessment will include the drilling and installation of one offsite groundwater monitoring well. Based on existing site monitoring data, groundwater is expected to be encountered at a depth of approximately 7 feet bgs. As 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), SECOR will prepare a Site-Specific Health and Safety Plan prior to the commencement of fieldwork. The Site-Specific Health and Safety Plan will be reviewed by the field staff and contractors before beginning field operations at the site. An plicable permits for well installation and encroachment will be obtained from SJCPHS and the City of Tracy prior to drilling. The specific scope of work is discussed below: • Drilling and Groundwater Monitoring Well Installation. One boring will be drilled northwest of the site at the location shown on Figure 2. Upon completion of drilling, a 2-inch diameter groundwater monitoring well will be installed in the boring. The well will be located northwest (downgradient) of the former site facilities and northwest of the current most-downgradient well MWA . Based on previous investigation at the site, groundwater is anticipated to be encountered at approximately 7 feet bgs. • Soil Selection and Analysis. Soil samples will be collected at 5-foot intervals and will be sent under chain-of-custody procedures to a California State-certified laboratory. Selected soil samples will be analyzed for total petroleum hydrocarbons calculated as gasoline (TPH-g) and total petroleum hydrocarbons calculated as diesel (TPH-d) using modified EPA Method 8015, and benzene, toluene, 76007-044-01 M'P LAN.DOC