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s • measuring approximately 30 grams from an undisturbed soil sample, placing this subsample in a sealed container (either a zip-lock bag or a mason jar). The container will be warmed for approximately 20 minutes (in the sun), then the head-space within will be tested for total organic vapor, measured in parts per million as benzene (ppm; volume/volume). The instrument will be calibrated prior to drilling using a 100-ppm isobutylene standard (in air) and a sensitivity factor of 55 which relates the photo-ionization potential of benzene to that of isobutylene at 100 ppm. The results of the field testing will be noted on the boring logs. PID and FID readings are useful for indicating relative levels of contamination, but cannot be used to evaluate hydrocarbon levels with the confidence of laboratory analyses. Groundwater Monitoring Well Installation Three borings will be converted into groundwater monitoring wells by installing 2-inch diameter, flush-threaded, Schedule 40 PVC casing with 0.010-inch factory-slotted screen. An RMC 2/12 sand pack, or equivalent, will be placed in the annular space across the entire screened interval, and will extend approximately 2 feet above the top of the screen for the well. A 2 to 3 foot bentonite transition seal will be placed atop the sand pack, and a Portland cement seal will extend from the bentonite transition seal to the ground surface. The Portland cement seal will be emplaced by pressure grouting through a tremie pipe from the bottom of the interval to be filled to the top. The boring . log will show well construction details. The groundwater monitoring wells will be developed after completion. The development procedure will consist of pumping or bailing water from the well until the water is visibly clear, or until a minimum of ten casing volumes have been removed. Laboratory Procedures Selected soil samples and groundwater samples collected will be analyzed for the presence of total petroleum hydrocarbons calculated as gasoline, total petroleum hydrocarbons calculated as diesel, benzene, toluene, ethylbenzene, and xylenes, and oxygenates (including MtBE) using modified EPA Methods 8015, 8020, and 8260. Soil Cuttings and Purge Water Soil cuttings generated during drilling operations will be temporarily stored onsite on and covered with plastic sheeting pending characterization and disposal. Soil cuttings will be removed by Chevron's disposal contractor to an appropriate disposal facility. Water generated during steam cleaning, and sampling of the HydropuncO borings will be temporarily stored in DOT-approved 55-gallon drums pending transport by Chevron's disposal contractor to an appropriate disposal or treatment facility. 9200781A/SOLGWRPT E -2 November 24, 1997