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APPENDIX H FIELD AND LABORATORY PROCEDURES Exploratory Drilling, and Soil Sampling The soil boring for MW-10 and MW-11 were drilled using an 8-inch hollow-stem auger drilling equipment to a depth of approximately 40 feet bgs The soil boring for DMW-2 and DMW-3 were drilled using an 8-inch hollow stem auger drilling equipment to a depth of approximately 80 feet bgs Borings were logged by a SECOR geologist under the direction of a California Registered Geologist using the Unified Soil Classification System and stan- dard geologic techniques Soil samples for logging were collected at 5-foot intervals using a California-modified split-spoon sampler to the total depth explored The sampler was driven a maximum of 18 inches using a 140-pound hammer with a 30-inch drop Organic Vapor Procedures Soil samples collected during drilling were analyzed in the field for ionizable organic compounds using 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 sealed container The container was warmed for approximately 20 minutes (Fn the sun), and the headspace within was tested for total organic vapor, measured in mg/kg as benzene (volume/volume) The instrument was calibrated prior to drilling using a 100-mg/kg isobutylene standard (in air) and a sensitivity factor of 55, which relates the photo-ionization potential of benzene to that of isobutylene at 100 mg/kg The results of field-testing are noted on the boring logs PID or FID readings are useful for indicating relative levels of contamination, but cannot be used to evaluate petroleum hydrocarbon levels without the confidence of laboratory analyses Soil Sampling Soil samples selected for chemical analysis were retained in brass liners, capped with Teflon squares and plastic end caps, and sealed to clean zip-lock bags The samples were placed on ice and transported to the laboratory with chain-of-custody documentation Down-hole drilling and sampling equipment was steam-cleaned following the completion of the soil borings Down-hole sampling equipment was washed in a tri-sodium phosphate or alconox solution between samples Extraction Well Installation One 6-mch diameter, schedule 40 PVC well casing with a 6 inch diameter, 0 02-inch stainless steel wire wrap well screen was installed in the 12-inch borehole for EW-2 A 2 x 12 sand filter pack was placed above 0 5-foot of sloughed soil from the base of the boring throughout the length of the screen interval to approximately 1 foot above the well screen, (approximately 18 feet bgs) A 2-foot thick bentonite layer was placed above the sand filter pack from approximately 18 feet bgs to 16 feet bgs The well was secured by a locking