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Additional Phase II Environmental Site Assessment Report Buena Vista Storm Drain,Stockton,CA August 15,2005 Page 2 At the request of KSN, Condor prepared the Phase II Environmental Site Assessment Work Plan, dated February 7, 2005, for submittal to the San Joaquin County Environmental Health Department(SJCEHD). Margaret Lagorio of the SJCEHD verbally approved the work plan on February 18, 2005. On March 15, 2005 Condor conducted a groundwater investigation utilizing direct push technology at the Site. Condor prepared the Phase II Environmental Site Assessment Report, dated March 30, 2005, describing the results of the work. Laboratory analytical results of the groundwater samples and field observations indicated that MTBE was detected in the groundwater sample collected from the boring (GP-5) installed in front of the property located at 1930 West Fremont Street. KSN requested Condor further investigate the lateral extent of MTBE contamination in groundwater in the vicinity of boring GP-5. Condor prepared the Addendum to Phase II Environmental Site Assessment Work Plan for the Buena Vista Storm Drain in Stockton, dated July 8, 2005. The addendum was submitted to the SJCEHD and incorporated into the original Phase II Environmental Site Assessment Work Plan that had been previously approved. 3.0 DIRECT PUSH BORING FIELD PROCEDURES This section includes a description of Site preparation activities and direct push boring procedures. 3.1 'SITE PREPARATION An addendum to the previously prepared Phase II ESA drilling permit was prepared by Condor and submitted to the SJCEHD for four proposed direct push borings.An encroachment permit application was prepared and submitted to the City of Stockton for the borings. Condor received the approved drilling permit addendum and the City of Stockton encroachment permit prior to initiating any fieldwork. The proposed boring locations were marked with white paint and Underground Service Alert (USA) was notified 48 hours in advance of the fieldwork to locate and identify underground utilities in and near the work area. 3.2 GROUNDWATER SAMPLING A Condor geologist was on Site to supervise the work. 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 four direct push borings (GP-13, GP-14, GP-15, and GP- 16) to collect groundwater samples on July 26, 2005. The boring locations are shown in Figure 2, Appendix A. The direct push borings were hydraulically advanced using a two-inch outside diameter conical bit. The bit and associated push rods were thoroughly cleaned before each borehole was advanced using laboratory-grade, non-phosphate detergent and deionized water and double-rinsed with deionized water. Borings GP-13 and GP-14 collapsed to 15 feet when trying to insert temporary PVC screen into the borings for the collection of groundwater samples. A decision was made to utilize a discrete-depth- sampling tool since the borings kept collapsing. The sampling tool has a sealed,retrievable stainless steel screen. The sampling tool was pushed in a closed position to groundwater. The sampling tool push rod was then retracted and the casing was raised approximately four feet to allow groundwater to pass through the screen and into the sample chamber. A groundwater sample was retrieved from within the screen with a length of clean, 3/8-inch diameter polytygon tubing equipped with a check valve at the bottom. The tubing was moved up and down by hand to draw groundwater up inside the tubing. The groundwater samples were discharged directly from the tubing into laboratory supplied sample containers. The sample a CONDOR