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r 1 I�p . i II i Ilk ' 3 ATTACHMENT A I f t FIELD AND LABORATORY PROCEDURES II k 1 �� t Soil Borings and Groundwater Monitoring Well Installation ' The soil borings and groundwater monitoring wells were drilled using 8-inch hollow-stem ' auger drilling equipment 'and logged by a Pacific Environmental Group, Inc. geologist using the Unified Soil Classification System and standard geologic techniques. Soil samples for logging were either continuously cored or collected at 5-foot depth intervals using a Califor-. nia-modified split-spoon sampler. Continuous core was collected using a stainless steel 5-foot by 3-inch:'diameter core barrel. The California sampler was driven a maximum of 18 inches j using a 1.40-pound hammer,Mith a 30-inch drop. Soil samples for chemical; analysis were retained in brass Iiners; capped with TeflonO squares and plastic end caps, taped, and sealed ' in clean zip-lock 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 following the completion of the soil borings'. Down-hole sampling equipment was washed in a tri-sodium phosphate solution between samples. i The borings were be converted 11 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 to 20 feet of screen was placed in the bottom of the boring. An RMC 2 x 12 sand pack was placed in the annular space across the entire screened interval, and extends approxi- mately 2 feet above the top of the screen for the well. A bentonite and Portland cement seal extends from the sand pack to the ground surface. s Following well completion, ithe vault box elevation and the elevation of the top of the PVC well casing of the monitoring wells were surveyed to the nearest 0.01 foot, relative to mean sea level, by a licensed surveyor. The boring logs show well construction details. li Organic Vapor Procedures 13 r Soil samples collected at 5-foot depth intervals during drilling Were analyzed in the field for ionizable organic compounds using the HNU Model PI-101 (or equivalent) photo-ionization detector (PID) with a 10.2 eV lamp. The test procedure involves measuring�;approximately 3 20153 1 MkEPORT ;: A - 1 September 13, 1995 ` i