SITE INFORMATION AND CORRESPONDENCE

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Chevron Pipeline Easement Environmental Assessment Report November 21,2001 Page 3 brought to the surface in the backhoe bucket. Soil samples were collected from soil in the backhoe bucket by pushing a two-inch diameter brass tube by hand into the soil in the bucket. The tube was sealed at the ends with "Teflon® sheeting, capped, and labeled. The samples were stored in a cooler chilled with Blue Ice and delivered, under chain-of-custody procedures, to Zymax Envirotechnology, San Luis Obispo, California, for analysis. Additional soil from the immediate area where the sample was collected from the bucket was collected by hand and placed in a plastic bag for testing with a photoionization detector (PID) for the presence of organic vapors. The location of the trenches and soil sample locations are shown on Figures 4, 8, and 9, located in Appendix A. Geological logs of the trenches are located in Appendix B. 3.4 DIRECT PUSH SOIL BORING PROCEDURES A Condor geologist was on site to supervise the soil borings. Prior to commencement of fieldwork, a tailgate safety meeting was held and a site-specific Health and Safety Plan was discussed with, and presented to, all .field personnel for their signatures. The investigation included the advancement of 185 soil borings with direct push technology(Geoprobe). The borings were installed at 100-foot intervals on the south shoulder of Byron Road between the Alameda County line and Mountain House Creek and between approximately 200 feet east of Mountain House Parkway and Wicklund Road. The borings were installed at 50-foot intervals on the south shoulder of Byron Road between Mountain House Creek and approximately 200 feet east of Mountain House Parkway. Borings were installed at 25-foot intervals adjacent to four previous borings (GP9, GP53, GP64, and GP 108) that encountered contaminated soil on the south shoulder of Byron Road west of Mountain House Creek. The borings were installed approximately two to six feet from the pavement edge of Byron Road due to the presence of several underground Pacific Bell telephone lines south of the road. Five of the borings were advanced in an alfalfa field southeast of the intersection of Mountain House Parkway and Byron Road to investigate the possibility of soil and groundwater contamination in the vicinity of a storm drain line that is to be installed at that location. Four of the borings were installed north of the railroad right-of-way across from each of four previous borings (GP9, GP53, GP64, and GP108) to investigate the possibility of downgradient contamination. Three of the borings were installed in an alfalfa field north of the railroad right-of-way and east of Mountain House Creek near the location of trenches two through five (Figure 8, Appendix A) for the purpose of further investigating the possibility of soil contamination at depth. One boring was advanced on the north shoulder of Byron Road about 250 feet east of Mountain House Parkway across from the adjacent borings GP96, GP97, and GP 117, all of which had encountered contaminated soil. The soil borings were hydraulically advanced using a 1.75-inch diameter bit. The bit and associated push rods were thoroughly cleaned before each boring was advanced using laboratory-grade, non- phosphate detergent and tap water and double rinsed with tap water. Upon completion of the drilling and sampling, the borings were grouted with neat cement to within 18 inches of the ground surface. The remainder of the boring was filled to the surface with soil from the borings. This method of backfilling the borings was directed by Mr. Michael Infurna, Jr., of the SJCEHD, to reduce the impact of the backfill on future roadwork on the shoulder of Byron Road. The locations of the borings are shown on Figures 3 through 14, located in Appendix A. 3.4.1 Soil Sampling The direct push borings were advanced to a depth of 16 feet bgs from the Alameda County line to approximately 3,000 feet east of Kelso Road, to a depth of 20 feet bgs from approximately 3,000 feet n CONDOR