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Ms. Victoria McCartney S E C O R June 11, 2004 Page 2 CONE PENETROMETER TEST AND SAMPLE COLLECTION Between March 29 and April 8, 2004, SECOR supervised Gregg In Situ Incorporated (Gregg) of Martinez, California, as they advanced two CPT borings (CPT-5 and CPT-6) to assess soil lithology and stratigraphy at each loc ion. Borings CPT-5 and CPT-6 were advanced to depths of approximately 175 feet and 11f�feet below ground surface (bgs), respectively. Lithology and pore pressure were continuously recorded and used to develop a hydrogeologic profile in the vicinity of the borings. During completion of boring for CPT-5, steel rods were advanced to 90 feet bgs and retracted after failing to encounter a shallow sand layer. The rods were re-advanced to approximately 175 feet bgs in the same borehole. Lithology and pore pressure was recorded and duplicated for CPT-5 (CPT-5A) between 0 and 90 feet bgs. Immediately adjacent to each CPT borehole a second direct-push borehole was advanced to collect depth-discrete groundwater samples. CPT logs are presented in Attachment 3. The findings of the CPT activities are summarized below. Subsurface Conditions Soil lithologies encountered during advancement of the CPT borings consisted predominantly of silt to clayey silt with minor amounts of silty clay, sandy silt, and clay. Sand lenses were encountered from approximately 105 feet to 106 feet bgs, 113 feet to 117 feet bgs, and 127 feet to 130 feet bgs at CPT-5N, nd from approximately 32 feet to 34 feet bgs at CPT-6. Hydropunch Groundwater Sampling An additional direct-push boring was advanced near each CPT boring and a total of five groundwater samples were collected from water-bearing zones identified during the advancement of the CPT borings. The groundwater samples were collected using a Hydropunch at depths of 81 feet bgs and 116 feet bgs next to CPT-5, and at depths of 35 feet bgs, 67 feet bgs, and 110 feet bgs near CPT-6. The findings of CPT activities are summarized below. ' �... Hydropunch groundwater samples were submitted to Lancaster Laboratories Incorporated (Lancaster) of Lancaster Pennsylvania for chemical analysis. The samples were analyzed for total petroleum hydrocarbons as gasoline (TPHg), total petroleum hydrocarbons as diesel (TPHd), total petroleum hydrocarbons as motor oil (TPHmo), benzene, toluene, ethylbenzene, total xylenes (BTEX), methyl tertiary butyl ether (MtBE), tertiary butyl alcohol (TBA), tertiary amyl methyl ether (TAME), ethyl tertiary butyl ether (EtBE), di-isopropyl ether (DIPE), ethylene dibromide (EDB), and 1,2-dichloroethane (1,2-DCA). Hydropunch groundwater analytical data and chain-of-custody documentation is presented in the laboratory analytical report in Attachment 4 and summarized below and in Table 1. I:1Chevron1905571REPORTS1200412004 Site Assessment. RevS.doc