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S IAC ® R • APPENDIX E FIELD AND LABORATORY PROCEDURES Exploratory Drilling Borings AS-8 through AS-10, and MW-1 R through MW-3R, were advanced using a sonic or air casing hammer drill rig to protect against vertical migration of contaminants while allowing logging of soil stratigraphy Soil boring AS-11 was drilled using 8-inch hollow-stem auger drilling equipment The borings were logged by SECOR field staff using the Unified Soil Classification System and standard geologic techniques Soil samples were collected at h 5-foot depth intervals using a California-modified split-spoon sampler The sampler was f driven a maximum of 18 inches using a 140-pound hammer with a 30-inch drop All sod samples for chemical analysis were retained in brass sleeves, capped with Teflon® squares and plastic end caps, and sealed in Ziplock"m-style 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 prior to and following the completion of the soil borings Down-hole sampling equipment was washed in a trisodium phosphate or alconox solution between samples Organic Vapor Procedures Soil samples collected at 5-foot depth intervals during drilling were analyzed in the field for ionizable organic compounds using a photo-ionization detector (PID) with a 10 2 eV lamp Y The test procedure involves measuring approximately 30 grams of an undisturbed soil t • sample and placing this subsample in a ZiplockTM-type bag The container was warmed for approximately 20 minutes (in the sun), then the head-space within the container was tested for total organic vapor, measured in parts per million as benzene (ppm by volume) The instrument was calibrated prior to drilling The results of the field-testing was noted on boring logs PID readings are useful for indicating relative levels of contamination but cannot be used to evaluate petroleum hydrocarbon levels without the confidence of laboratory analyses Hydropunch Groundwater Sampling Each grab groundwater sample was collected using a modified HydroPunch®sampler Prior to sampling, a water level meter was used to confirm that the drive rods do not contain water The sampler was driven to approximately 3 feet below the desired sampling depth and retracted 3 feet to expose the disposable schedule 20 polyvinyl chloride (PVC) screen and allowed groundwater to enter the HydroPunch® sampler The water sample was collected by lowering a3/4"-diameter stainless steel bailer through the drive rods to groundwater The groundwater was bailed from the drive rods, decanted from the bailer into 40-m1 VOA vials, and capped Each VOA vial was checked to ensure no bubbles are present, labeled, placed on ice, and transported to the laboratory under chain-of-custody documentation The drive rods were retracted, leaving the disposable drive tip and 4 foot length of PVC well screen in the hole Groundwater Monitoring Well Installation and Development Each groundwater monitoring well was completed by installing a 2-inch diameter, flush- threaded, schedule 40 PVC casing with 0 020-inch factory-slotted screens Approximately 15 feet of screen was used to construct the monitoring wells A #3 sand pack was placed in the annular space across the screened interval, extending approximately 2-feet above the top of the screen A 2-foot bentonite transition seal was placed atop the sand pack, followed