Laserfiche WebLink
i <br /> 1 <br /> time sampled and analysis) , sealed in zip lock baggies, placed in <br /> a cooler with ice and cooled to 4-C. The samples were then chain <br /> of custody, hand delivered to the laboratory performing the <br /> analysis (Chemtech) . <br /> Soil samples were obtained from the borings of the vapor <br /> extraction wells using a California split spoon sampler that <br /> contains 3 2"x6" sterile brass sleeves. A 140 pound drop hammer <br /> powered by Hog'ates Drilling cathead was r3ed to drive the sampler <br /> and "blows count" required to drive 6 were recorded. The <br /> excavations were sampled by hand augering a 6" diameter hole six <br /> inches below the base of the excavation, then obtaining the sample <br /> by hand driving a 211x6" sterile brass sleeve that had been <br /> inserted into a. barrel sampler attached to rod extensions and a <br /> slam bar. Between sample intervals both samplers were cleaned <br /> with trisodium ;phosphate and clean water rinse. Upon obtaining <br /> oil samples, the s <br /> the sleeves were withdrawn from the sample <br /> barrel and the uncovered ends were screened with the IikrU-PID, then <br /> the sleeved sample exhibiting the highest response from the PID <br /> was sealed with aluminum foil, plastic end caps, then sealed with <br /> duct ta;je, labeled, put into a zip lock freezer bag, and placed <br /> upon dry ice in a cooler for preservation. The chain of custody <br /> was filled out prior to leaving the site and the samples were hand <br /> delivered to Che:mTech Laboratories (State of California Cert. # <br />` 359) for analysis;, see Appendix B. <br /> SLUG TEST <br /> On monitoring w <br /> nd water monNovember 27 1990, WEGE performed a slug test on all <br /> ofMW6)e <br /> grouiiells (MW1, MW2, MW3, MW4, , an <br /> Using the Bouvier and R''=ce method for predicting hydraulic <br /> conductivities (K) ground water velocities were calculated, see <br /> Figure 5 and Tables 3 MW1 thru MW6. The results of the slug test <br /> showed that the: formation near the wells is of a silty fine sand <br /> with the highest ground water velocity being near MWl and forms a <br /> velocity dome at this well which spreads southeast and northwest <br /> towards monitor wells xW6 and MW2, see Figure 5. Using the <br /> velocity fromHW 25 down feet gradient well, the contaminant plume would <br /> travel less than <br /> VAPOR EXTRACTION PILOT TEST <br /> ompletion of <br /> At cthe construction of the vapor extraction wells a <br /> - ----- -— ---- -- - request-was-made-to-son-Joaquin-County--.Air--Quality-Board_(SJC-AQD) <br /> re perform a. source-pilot test for vapor` extraction ox the - --- ------- - —-- <br /> gasoline range hydrocarbons still present near the over- <br /> excavations of the tank field and pump island areas. The <br /> recovered vapors were absorbed onto activated charcoal and Cameron-Yakama <br /> destroyed by regeneration of then <br /> ` ,.. charcoal by <br /> page 7 <br />