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• ATTACHMENT A FIELD AND LABORATORY PROCEDURES 1 ' Exploratory Drilling and Soil Sampling The soil borings were advanced using either 8-inch or 10-inch hollow-stem auger drilling equip- ment. Borings were logged by a SECOR representative using the Unified Soil Classification t System and standard geologic techniques. Soil samples for logging were collected continuously using either a California-modified split-spoon sampler (above groundwater), or a Simul-Probe® or Enviro-Core® sampler. All soil samples for chemical analysis were retained in brass, stainless steel, or plastic liners, capped with Teflon squares and plastic end caps, and sealed in zip-lock bags. The samples were placed on ice for transport to the laboratory accompanied by chain-of- custody documentation. All down-hole drilling and sampling equipment was steam-cleaned following the completion of the soil boring. Down-hole sampling equipment was washed in a tri-sodium phosphate or alconox solution between samples. Well Installation The borings were converted to groundwater monitoring wells by installing either 2-inch or 4-inch diameter, flush-threaded, Schedule 40PVC casing with 0.020-inch factory-slotted screen. The screen intervals were installed in each well as described in the approved work plan. An RMC2/12 sand pack, or equivalent, was placed in the annular space across the entire screened interval, and extends approximately 1 to 2 feet above the top of the screen for the well. A ' bentonite and Portland cement sea] extends from the sand pack to the ground surface. The boring logs show well construction details. The wells developed and sampled after completion. The development procedure for each well consists of pumping or bailing water from the well until the water is visibly clear, the well goes dry, or until a maximum of ten casing volumes have been removed. After development, water levels are allowed to partially recover. Groundwater samples are then collected using a disposable teflon bailer, placed into appropriate EPA-approved containers, labeled, placed on ice, and transported to the laboratory accompanied by chain-of-custody documentation. ' Ozone Sparge Point Installation ' The borings were converted to dual completion ozone spargepoints by installing two (2) 2-inch diameter spargepoints with a 3/a-inch PVC riser extending to the surface. The spargepoints are approximately 2-112 feet in length. A grade of sand appropriate to the screen size was placed in the annular space of the lower spargepoint, across the entire screened interval, and extends approximately 2 feet above the top of the screen for the spargepoint. A bentonite seal extends two feet above the sand pack. Neat cement extends from the bentonite seal to the bottom of the upper spargepoint. A grade of sand appropriate to the screen size was placed in the annular space • A-1