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r Earth Systems Consultants 47853 Warm Springs Blvd. 1 Northern California Fremont, CA 94539-7400 (510) 353-0320 Fax(510) 353-0344 File No. NFE-4533-01 Doc, No. 9908-086 August 24, 1999 Pombo Real Estate 1755 West 11`h Street Tracy, California 95378-0805 Attention: Mr. Ernie Pombo, Jr. Subject: 1755 West 11`h Street rTracy, California �+ CHEVRON RIGHT-OF-WAY RELOCATION PRELIMINARY ASSESSMENT SOIL SAMPLING Dear Mr. Pombo: Earth Systems Consultants Northern California (ESCNC) is submitting the methods and results of the soil sampling conducted along the former right-of-way for Byron Road on the northern portion of the property associated with 1755 West I I`h Street in Tracy, California. (Figure l) The investigation was directed by Chevron Pipe Line Company (CPL) to relocate the CPL right-of-way located on the south side of the former Byron Road. Field Work r On July 29, 1999, an ESCNC geologlist supervised the advancement of four soil borings (EB7 L• through EB10) using a drill rig operated by Exploration Geoservices, Inc. (C57 484288). The borings were drilled to depths ranging from 13.5 to 21.5 feet below ground surface (bgs) at the locations shown on Figure 2. The boring locations were determined by CPL, and the field work was overseen by Mr. Lange Jorstad of Geomatrix Consultants (Geomatrix), the consultant for CPL. Soil from each of the borings was observed and described. Soils encountered in borings EB8 and, EB10 did not contain visual evidence or odors indicating hydrocarbon contamination. As directed by Ms. Elizabeth Lu of Geomatrix, soil samples were not collected from these borings. However, soils encountered in borings EB7 and EB9 contained visual evidence and odors indicating hydrocarbon contamination. Therefore, samples were collected from boring E137 at a depth of 9 feet bgs and from,boring E139 at a depth of 14.5 feet bgs. Samples From similar depths were collected and submitted to Geomatrix Soils encountered consisted predominantly of clay. Borings EB7 and EB9 contained hydrocarbon- bearing soils beginning at a depth of approximately 6 feet bgs and extending to a depth ranging from 10 to 13 feet bgs in boring EB7 and a depth ranging from 17.5 to 20 feet bgs in boring EB9. The depth to groundwater was 12 feet bgs in boring EB7 and 12.9 feet bgs in boring EB9. Groundwater was not encountered in borings E138 and EB 10. As directed by CPL, no groundwater samples were collected. Boring logs are included in Attachment A. Analytical Methods The soil samples collected from borings EB7 and E139 were delivered to Chromalab in Pleasanton, California (FLAP #1094) and analyzed for total extractable petroleum hydrocarbons (TEPH) as