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APPENDIX A FIELD PROCEDURES Monitoring Well -Construction The wells were drilled with a truck-mounted Mobile B-61 drill rig equipped with hollow-stem augers provided by B & F Drilling Company Soil samples were collected from the borings at five-foot maximum intervals with a modified California sampler equipped with clean, two-inch diameter, six-inch long brass tubes, samples and drill cuttings were described in the field using the Unified Soil Classification System (USCS) Sample tubes were sealed with polytetrafluoroethylene (PTFE)-coated sheets, plastic end caps and duct tape to reduce volatile hydrocarbon loss Selected samples were placed in an ice chest containing ice, and submitted under chain-of-custody to a California-certified laboratory I for analysis of Total Petroleum Hydrocarbons (TPH)using Modified EPA method 8015/Purge-and-Trap and for Benzene, Toluene, Ethylbenzene, and Total Xylenes (BTEX), using EPA method 8020/Purge- and-Trap The soil borings were converted to monitoring wells Each well was constructed using four-inch diarrcter, flush-jointed, Schedule 40 PVC casing, 0 02-inch slotted casing was used for the screened Iinterval Number 3 Monterey sand was placed in the well annulus as a filter pack using the tremie method The filter pack extends from the bottom of the screened interval to approximately two feet above the top of the screened interval A two-foot thick bentonite seal was placed in the well annulus above the, filter pack A grout seal consisting of a Portland Cement and bentonite slurry was tremied into the well annulus above the bentonite seal Each well was completed with a locking well cap and a flush-mounted, traffic-rated well cover As-built well diagrams are shown on Plates 3 and 4 The wells were constructed under the supervision of a California Registered Geologist M nitorin Well Development, Purging and Sampling After well construction was completed, the water level in each well was measured with an electronic well sounder and the wells were checked for free product using a clear bailer The wells were subsequently developed using a vented surge block Approximately three well volumes of water were then removed with a suction pump until temperature, pH and conductivity readings stabilized and/or the water cleared of sediment After a minimum of 24 hours from the time of development, the water level in the wells was measured, and the water checked for visual signs of free product using a clear bailer Approximately three to five additional well volumes of water were purged using a clean, submersible I pump until temperature, pH, and conductivity readings stabilized and/or the water cleared of sediment The water samples were then collected using a new polyethylene disposable bailer Water from the bailer was decanted into appropriate sample containers provided by the laboratory The samples were immediately placed in an ice-chest with ice, along with a travel blank, and submitted under chain-of- 6 custody to a California-certified laboratory for analysis of Total Petroleum Hydrocarbons (TPH) using EPA method 80151Purge and Trap, and Benzene, Toluene, Ethylbenzene and Total Xylenes (BTEX) WALLACE KUHL Recwied papa &ASS C AYES INC