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20 August 2003 <br /> AGE-NC Project No 95-0173 <br /> Page 2 of 8 <br /> at regular purge-volume Intervals using an Oakton water analyzer Field data and logs are included <br /> in Appendix A Purged ground water was containerized in 55-gallon drums and was stored on-site <br /> In an area lacking general public access <br /> iMulti-level monitoring well MW-13 (A-C) and the deep (screen interval B) air sparge wells were <br /> purged by lowering and raising a3/8-inch outer diameter,length-discrete polyethylene hose equipped <br /> with a ball-valve water tip through the top chambers into the specific water-charged screened <br /> section, a Watera-Hydro-Lift II pump equipped with a mechanical arm was utilized to surge the <br /> polyethylene hose Approximately 3%2 to 5% gallons of ground water (a minimum of three casing- <br /> water volumes per well)were purged from each multi-level well chamber and between 14 and 24 <br /> gallons purged from air sparge wells AW-1B and AW-2B Temperature,pH and conductivity were <br /> measured for stabilization at regular purge-volume intervals from each well using the Oakton water <br />' analyzer Field data and logs are in Appendix A Purged ground water from the above wells was <br /> transferred to 55-gallon drums and stored on-site in an area lacking general public access <br /> 2 2 GROUND WATER SAMPLING <br /> rFollowing well purging,ground water levels in the wells achieved a minimum of 80 percent recharge <br /> prior to sample collection, except for well MW-11 which was purged `dry' Subsequently, ground <br /> water samples were collected from the single-level monitoring wells and shallow air sparge wells <br /> utilizing new,disposable polyethylene bailers and transferred into 40-m1 EPA-approved VOA vials <br /> containing 0 5 ml 18%hydrochloric acid as a sample preservative, ground water samples from the <br />' multi-level well and deep air sparge wells were collected directly into the 40-m1 volatile organic <br /> analysis (VOA) vials utilizing the Watera hose bailer Care was taken to ensure that visible air <br /> bubbles were not present in the vials after filling and capping Ground water sample containers were <br />' labeled with the well designation, date, time, and sampler's initials <br />' 23 LABORATORY ANALYSIS OF GROUND WATER SAMPLES <br /> After labeling,each ground water sample was logged on a chain-ot-custody form,placed in a chilled <br /> container and transported to Castle Analytical Laboratory, a California Department of Health <br /> Services (DHS)-certified laboratory to be analyzed for <br /> e Total petroleum hydrocarbons quantified as gasoline(TPH-g)by EPA Method 5030/8015M, <br /> • Benzene,toluene,ethylbenzene and xylene(BTEX)and methyl tertiary-butyl ether(MTBE) <br /> by EPA Method 8020, and <br /> i <br />' Advanced GeoEnviron mental,Inc <br />