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S E C O R ATTACHMENT D FIELD AND LABORATORY PROCEDURES Exploratory Drilling Geoprobe borings were advanced using 1 5" direct push drilling rods and the soil borings for wells MW-10 through MW-15 were drilled using 8-inch hollow-stem auger drilling equipment The boring was logged by a SECOR geologist using the Unified Soil Classification System and standard geologic techniques Soil samples were collected at 5-foot depth intervals using a California-modified split-spoon sampler or direct push sampler The sampler was driven a maximum of 18 inches using a 140-pound hammer with a 30-inch drop All soil samples for chemical analysis were retained in brass or plastic liners, capped with Teflon® squares and plastic end caps, and sealed in ZiplockT""-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 flame-ionization detector (FID) or a PID with a 10 2 eV lamp The test procedure involved measuring approximately 30 grams from an undisturbed soil sample, placing this subsample in a ZiplockTM-type bag or in a clean glass far, and sealing the far with aluminum foil secured under a ring-type threaded lid 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, volume/volume) The instrument was calibrated prior to drilling The results of the field- testing were noted on the boring logs (Attachment 4) FID/PID readings are useful for indicating relative levels of contamination, but cannot be used to evaluate petroleum hydrocarbon levels with the confidence of laboratory analyses Groundwater Monitoring Well Installation and Development The groundwater monitoring wells were completed in the soil boring by installing a 2-inch diameter, flush- threaded, Schedule 40 PVC casing with 0 020-inch factory-slotted screen Approximately 20 feet of screen was used to construct the monitoring wells An RMC 2112 sand pack, or equivalent, was placed in the annular space across the entire 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 by a cement seal, extending from the top of the bentonite transition seal (1 feet bgs) to the ground surface The boring log shows well construction details The groundwater monitoring wells were developed by SECOR The development procedure for the well consisted of pumping and bailing water from the well until the water was visibly clear, the well went dry, or until a maximum of ten casing volumes had been removed AssmtRpt doc