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ATTACHMENT A FIELD AND LABORATORY PROCEDURES Geoprobe®Boring Procedures The Geoprobe®bonngs were advanced using a direct-push, hydraulic and percussion drive-point sampling system This involved the driving of a one-inch outer-diameter screen point sampler to groundwater (approximately 14 feet bgs) Soil samples will be collected every 4 feet Once to groundwater, the sampler case was retracted a distance corresponding to the length of an enclosed 112-inch x 18-inch stainless steel screen This disengages an expendable point and allows the slotted screen to extend into the open borehole The water is then allowed to enter the sampler through the screen for collection Groundwater was collected from the boring using a mini-bailer, lowered to the screened interval through the hollow drive tube When water recovery was slow water was collected through a new piece of poly-tubing with a check valve at the bottom The boring was then be continued to approximately 30 feet bgs or until flowing sands were encountered A bentonite cement seal was emplaced by tremie pipe in one continuous operation from the bottom of the boring to the ground surface The samples were placed on ice for transport to the laboratory accompanied by chain-of-custody documentation The collected water samples were submitted to Sequoia Analytical, a California State-certified laboratory for analysis All down-hole drilling and sampling equipment was steam-cleaned following the completion of the soil boring Down-hole sampling equipment was washed in a tnsodium phosphate or alconox solution between samples Groundwater Monitoring Well Installation The monitoring wells were drilled using 8-inch hollow-stem auger drilling equipment The wells were logged by an IT geologist using the Unified Soil Classification System and standard geologic techniques Soil samples were collected at 5-foot depth intervals using a California- modified split-spoon sampler The sampler was driven a maximum of 18 inches using a 140-pound hammer with a 30-inch drop All soil samples for chemical analysis were retained in brass liners, capped with Teflon squares and plastic end caps, and sealed in Ziplocke-style bags The samples were placed on ice for transport to the laboratory accompanied by COC documentation All down-hole drilling and sampling equipment was steam-cleaned following the completion of the soil boring Down-hole sampling equipment was washed in a trisodium phosphate or alconox solution between samples S cDP-'WACRFpI1COMMOMCansalringWatalSharaAPmjwukm,sc1880-0401Aaado IT CORPORATION 12/4100