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• , KI KLEINFELDER 4 PUSH PROBE ASSESSMENT 4.1 PERMITTING AND PREFIELD ACTIVITIES Kleinfelder submitted a workplan as referenced in Section 3 to SJC/EHD for review and comment. SJC/EHD prepared an approval letter titled "Workplan — Limited Soil and i� Groundwater Assessment, Petroleum Pipeline Spill, 23577 Mountain House Parkway, Mountain �1 House, California," dated April 6, 2004 (See Attachment D). l Approved (push probe) boring permits were obtained prior to initiating the field activities. �I Underground Services Alert (USA) was contacted prior to field activities. A site meeting was scheduled prior to field activities on Tuesday May 18, 2004, including Kleinfelder, PG&E and Chevron representatives. The meeting was conducted to survey potential boring locations and to locate the working area limits of the Chevron and PG&E pipelines (proposed work area where visual soil contamination was noted). A backhoe and operator (Steve Serpa of Tracy) were subcontracted for exploratory excavation near the pipelines under the direction of the PG&E representative. The Chevron representative was able to locate the fiulhest portions of their pipeline 1 within the proposed working limits, without utilizing the backhoe since much of the pipeline was still exposed from previous repair activities. Caution tape was used between verified pipeline locations for reference during Kleinfelder's field activities at the request of the pipeline companies. For a copy of the well/boring pen-nits and SJC/EHD's workplan approval letter, please refer to Appendix D. 4.2 FIELD ACTIVITIES On May 19 and 20, 2004, a pushprobe assessment was conducted by Enprobe of Oroville, California. The assessment was generally conducted as per the SJC/EHD approved workplan written by Kleinfelder. The workplan included agreed upon changes suggested by both Chevron's representatives (Cambria Environmental) and Kagehiro Ranch, Inc. (Curtis and Arata Attorney's and Geocon Environmental). These comments were mostly regarding the number and spacing of probes and groundwater sampling and analyses. Based on field observations, additional sampling and analyses was also conducted. A total of twenty nine (29) push probes were advanced during the field activities. For r} approximate probe locations please refer to Plate 2. Twenty six (26) of the soil probes were �I advanced within the initially estimated footprint area of petroleum impacted soil and three pushprobes were advanced near the perimeter of the footprint area. Four of the deeper pushprobes (Gl through G4), including the three perimeter probes were advanced to assess groundwater conditions. Dual wall pushprobes methodology was used while advancing prope Gl within the footprint area to assist in reducing potential cross contamination from overlying petroleum constituent into groundwater samples. The three perimeter probes • were located to assess expected downgradient and upgradient groundwater conditions at location 44843.T03/ST04R1025 Page 6 of 16 Copyright 2004 Kleinfelder,Inc. August 6,2004