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Working To Restore Nature Addendum One to Remedial Action Plan March 1, 1993 Coca.-Cola Former Distribution Facility, Stockton, California 54006.01 hydrocarbons. Soil gas TPHg concentrations ranged from nondetectable to 90 ppm, weight to volume. The majority of vapors appeared to be located immediately south of the former gasoline UST. ' Initial Subsurface Investigation In August and September 1990, a subsurface environmental investigation was conducted by USTEC(USTEC, November 1990). A total of thirteen soil borings (B-1 through B-13)were -� drilled and five groundwater monitoring wells (MW-1 through MW-5)were installed in five of the borings. The locations of the soil borings and groundwater monitoring wells are shown in Plate 3. The bongs and wells were drilled to depths ranging from 70 to 95 feet below ground surface. Groundwater was encountered at a depth of about 70 feet. Soil Boring Samples Fifty-two soil samples were collected and submitted for laboratory analysis. The results of laboratory analyses are summarized in Table A-1 and Table A-2 and are listed under the August/September 1990 data. TPHg concentrations in soil ranged from nondetectable to 8,900 ppm (in B-5 immediately north of the former gasoline UST and at a depth of 20 feet). TPHd ranged from nondetectable to 20,000 ppm (again in B-5 at 20 feet). BTEX ranged from nondetectable to 920 ppm (total xylenes in B-5 at 20 feet). Organic lead, a constituent of leaded gasolines, was nondetectable in all samples except one where it was detected at 0.059 ppm in boring B-5 at a depth of 20 feet (refer to Table A-2). The majority of ' petroleum hydrocarbons were present from 0 to about 25 feet below grade, and within about 25 feet of the former tank pit. TPHg soil concentration contours summarizing this and all other subsurface investigations at the site are shown in Plate 4, TPHg Concentrations in Soil at Depths of 0 to 30 Feet. ' Polynuclear aromatic hydrocarbons (PNAs)were also analyzed, and results are summarized in Table A-2. PNAs were nondetectable in all samples, with the exception of naphthalene in B-1 at 10 feet and 15 feet (30 ppm and 32 ppm respectively); in B-3/MW-2 at five feet (33 ppm), and in B-5 at 20 feet (54 ppm). PNAs are not currently regulated in soil or water, but are regulated in air. Soil Stockpile Two samples were collected from the soil stockpile, and analyzed for: heavy metals; industrial solvents (by EPA Method 3810/8015); hazardous waste characteristics of reactivity, pH, flashpoint, and hazardous waste bioassays using flathead minnows. A2