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1 Well Installation Report X506 Pacific Avenue, Stockton California{CAo No 5-Oo7o71 _. EAl Project No 1232 ' A Mini Rae Photo-Ionization Detector PID calibrated against an isobut le . (PID) g y ne gas standard was 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 was analyzed using the PID The results of this field-testing are recorded on the boring logs (see Appendix B) ' 22 Monitoring Well Construction The wells were constructed of two-inch inside diameter flush threaded Schedule 40 polyvinyl chloride well casing All casing materials were steam cleaned prior to installation The ground water monitoring wells were designed with a slotted section (0 010-inch x 1-inch slots) The annular space between the borehole wall and well casing was backfilled with grade 92 Monterey sand to about two feet above the slotted section An approximate three-foot thick layer of hydrated bentonite chips was placed on top of the sand pack and the borings grouted to the surface using a cement slurry Flush mounted traffic grates were placed on all wells Appendix D contains the specific well construction details for each well Although minor layers of silt and clay exist between 85 and 105 feet bgs, neither well MW-23 SID nor MW-24 SID contained a good 5-foot aquitard within this interval (see Appendix B) After discussing the ltthology in well MW-23 S/D with Marty Hartzell it was his opinion that two well casings should still be installed to attempt to determine if the ground water at 85 and 105 feet is in the same aquifer and if contamination is present at both levels Similar lithologic conditions were observed in well MW-24 S/D Therefore, using the same logic, two well casings were also installed in this well 23 Equipment Cleaning Protocol All augers were steam cleaned prior to drilling each boring/well The sampler was disassembled and decontaminated prior to each sampling using the following procedure • All excess soil was scraped off the sampler parts • The sampler was washed in a solution ofAlconox detergent and tap water ' • The sampler was rinsed with tap water 2.4 Effluent Management All effluent generated during drilling and equipment decontamination activities was sealed in labeled 55-gallon drums The drums remained on the Site pending the results of the analytical testing, at which time the effluent was transported to an approved disposal or recycling facility by Belshire Environmental Copies of the manifests documenting proper handling of the effluent are available upon request B{IAh 1212RU121 3 ,ENVIRONMENTAL AUDIT, INC