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Wendy L. Cohen -2- 26 July 1995 Methods 8015, for semi-volatile organic compounds (VOCs) by EPA Method 8270, and for total metals according to Title 22 of the California Code of Regulations (CCR). The results showed TPH up to 330 mg/kg, and two semi-VOCs, 2-methyl-naphthalene and phenanthrene, at 2.4 ppm and 1.0 ppm, respectively. Several metals were also detected. A soil sample from Area 7 analyzed for polynuclear aromatic hydrocarbons (PNAs) by EPA Method 8310 and aromatic VOCs by EPA Method 8020 and showed nondetectable levels of these compounds. However, the sample had low concentrations of TPH and may not be representative of PNA and aromatic VOC concentrations where there are higher TPH concentrations at the site (Le., Area 4). WORK PLAN PROPOSAL Soil According to the work plan, soil samples will be collected at the locations shown in Attachment 2 (Figure 5 of the work plan) using Geoprobe sampling rods driven with a truck-mounted rig. Geoprobe cores will be collected at four foot intervals and at the capillary fringe estimated at 20 to 25 feet bgs. Boring logs will be based on field observations and flame ionization detector(FID) readings of the samples. A sample with the highest FID reading from each boring and a sample from the capillary fringe will be selected for laboratory analysis. Additional samples may be analyzed where there are indications of significant petroleum impacts. The work plan also states that a sample will be taken from the bottom of the boring in Area 4 to assess the vertical extent of petroleum impacted soil. The results from the Geoprobe investigation will be used in the placement of three soil borings to be completed as monitoring wells. The approximate locations of these wells are shown in Attachment 2. The borings will be installed to approximately 20 feet below the water table and one of the borings will be continuously cored from a depth of five feet bgs. The borings will be logged as in the Geoprobe work. Geoprobe soil samples will be analyzed for total extractable petroleum hydrocarbons (TEPH) by modified EPA Method 8015, for aromatic VOCs by EPA Method 8020, and for PNAs by EPA Method 8310. Ground Water After collection of soil samples, the geoprobe rods will be advanced below the water table at approximately 25 feet bgs and a water sample will be drawn for analysis. Free product may also be detected at this stage. The three borings will be completed as monitoring wells with a 20-foot screened interval extending a few feet above the water table. Following gradient measurement and development, the wells will be sampled, and if no free product is present, analyzed for TEPH and aromatic VOCs as above.