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WELL INSTALLATION AND CPT INVESTIGATION REPORT 540�and SG06 Pacific Avenue, Stockton._Cahforn�a(CAO N[1 5-00707) ,., EA[ Prosect No 1232 . 20 FIELD WORK 21 Drilling and Sampling ' Between September 19 and 21, 2001, ground water monitoring wells MW-81), MW-9, AS-26, and MW-27 were installed (see Figure 2) Appendix A contains a copy of the San Joaquin County Public Health Services (County Health) well permits (SR40027363, and SR#0027454) ' Issued to install the four wells One well permit was issued for each assessors parcel number associated with the wells ' The wells were drilled by West Hazmat Drilling of Rancho Cordova, California (License No 554979, C-57 Water Well Drilling), under the supervision of an EAI California registered geologist The wells were drilled using 8-inch outside diameter continuous flight hollow stem augers to depths ranging between approximately 65 and 107 feet bgs All borings were logged in accordance with the Unified Soil Classification System (see Appendix B) ' Soil samples were collected at approximately 5 feet bgs and at 5-foot Intervals thereafter until termination with the exception of borings MW-81) This well was drilled to a total depth of approximately 107 feet bgs To the extent practical, this boring was sampled continuously ' between 90 and 105 feet bgs The purpose of the continuous sampling was to attempt to identify a 5-foot thick aquitard layer between the 90 foot and 105 foot depths (see Appendix B) Marty Hartzell with the RWQCB reviewed the lithology for boring MW-8D and determined there is Insufficient aquitard between 90 and 105 feet bgs to warrant installing a second well between 85 and 90 feet bgs Therefore, the proposed shallow well (MW-8S) was not installed Soil samples were collected using three 2-Inch diameter b six-inch long biass tubes mount Y � ed within a 2-inch inside diameter split-spoon drive sampler employed in advance of the augers After sample recovery, the ends of the lowermost six-inch long tube were covered with Teflon tape and plastic caps taped over the ends Prior to use all tubes were washed in a solution of Alconox detergent and tap water, and rinsed with tap water The samples were labeled with the 1 sample point identification, depth interval, time and date, and EAI project number Each sample was individually sealed in a "Ziploc" plastic bag, and immediately placed into an ice chest chilled using Ice The samples were kept chilled until delivered to the laboratory for analytical testing All samples were logged on chain-of-custody record forms (see Appendix C) A Mini Rae Photo-Ionization Detector (PID) calibrated against an Isohntylene gac (A lard teas used on the soil contained in the second tube from the bottom of the shoe, at each sampling interval within the borings to determine If volatile hydrocarbon vapors were emanating directly from the soil Each sample was placed in an airtight "Ziploc" plastic bag The soil samples were allowed to sit in the bags for a minimum of five minutes and then the headspace in the bags t,Nas analyzed using the PID The results of this field-testing are Iecoided on the boring logs (sec Appendix B) • BHM WORD 1232RO191 3 ENVIRONMENTALAUDIT, INC