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ATTACHMENT B FIELD AND LABORATORY PROCEDURES Chevron Service Station 9-3232, 8660 Lower Sacramento Road, Stockton, California Health and Safety As required by the Occupational Health and Safety Administration (OSHA) Standard "Hazardous Waste Operations and Emergency Response" guidelines (29 CFR 1910 120), and by California Occupational Health and Safety Administration (Cal-OSHA) "Hazardous Waste Operations and Emergency Response" guidelines (CCR Title 8, Section 5192), SECOR prepared a Site-Specific Health and Safety Plan for use during fieldwork The field staff and contractors reviewed the Site-Specific Health and Safety Plan before beginning field operations at the site Exploratory Drilling The soil borings were advanced using 8-inch hollow-stem auger drilling equipment to approximately 46 feet bgs in the shallow borings and approximately 67 feet bgs in the deep borings A SECOR representative using the Unified Soil Classification System and standard geologic techniques logged continuous soil samples using a California-modified split-spoon sampler from the deep borings and in five foot intervals from the solo shallow well (MW-7) Soil samples were retained in brass liners, capped with Teflon squares and plastic end caps, and sealed in zip-lock bags The samples were then placed on ice for transport to the laboratory accompanied by chain-of-custody documentation Down-hole drilling and sampling equipment was steam cleaned prior to and following the completion of each soil boring Down hole sampling equipment was washed in a tri-sodium phosphate or alconox solution between samples Groundwater Monitoring Well Installation The borings were converted to groundwater monitoring wells by installing 2-inch diameter, flush-threaded, Schedule 40 PVC casing with 0 020-inch factory-slotted screen Approxi- mately 15 feet of screen was placed in the bottom of each shallow boring and approximately five to ten feet of screen was placed in the bottom of each deep boring A grade of sand appropriate to the screen size was placed in the annular space across the entire screened interval, and extends approximately 2 feet above the top of the screen for each well A bentonite seal extends two feet above the sand pack The monitoring wells were completed with neat cement from the bentonite seal to ground surface The well casings were topped with a locking cap The well heads are contained in watertight well boxes, traffic rated and flush mounted The boring logs show well construction details The wells were developed after completion by pumping or bailing water from each well until the water was visibly clear, the wells went dry, or until a maximum of ten casing volumes had been removed Slug Testing The slug test consists of quickly raising (slug insertion) or lowering (slug removal) the water level in a well from equilibrium and measuring the subsequent rate of rise or fall, respectively Slug insertion and slug removal tests were performed on each well using a slug