ARCHIVED REPORTS XR0012749 - Laserfiche WebLink

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= s 1r:7 „i 10 vapor meter to detect hydrocarbon vapors, These data will be recorded on the log. Soil samples will be collected for laborr,ory analysis at 10-foot intervals. The sample analyzed will be that sample having the highest detected vapor reading in that 10-foot interval. Brass liners conmining soil samples selected for laboratory analysis will be covered with aluminum foil and plastic caps and sealed with plastic tape. Each sample will be labeled on site to show the date,project numb:.r, sample location,and depth interval. The sealed samples will be stored on ice in closed chests and protected from meltwater. Selected soil samples will be t:nalyzed for BTX and TPH by U.S. Environmental Protection Agency(EPA)Method 8015,modiftpd, Extraction Method 5030. The samples will be delivered to Brown and Caldwell Analytir:; Laboratories, Inc. (KCAL), in Emeryville. Construction of Monitoring Wells. The monitoring wells will be completed with 30 feet of nominal 2-inch-diameter, PVC, 0.020-inch slotted flush-threaded easing. The slotted casing will extend approximately 20 feet below the groundwater surface and 10 feet above. This design will accommodate any seasonal groundwater level fluctuations that might cr_eur at the site. Blank casing will extend from the top of the perforated section to ground surface. PVC caps will be installed at the top and bottom of the v;ell. Actual depth of the borehole and screened interval will depend on the conditions encountered during drilling. 'The wells will be packed with No. 1/20 sand from the bottom of the screen to approximately 2 feet above the top of the screen. A. 2-foot-thick layer of bentonite pellets will be placed on the tap of the sand puck. The remaining - annular space will be grouted with bentonite-cement siurry placed by tremie pipe. The well will be complete''at grads:using a water-right locking cover. Typical well construction is illustrated on Figure 4. Well Development. The well will i;e de ver fed by surging,bailing,or pumping until clean, sediment-free water is produced from the well. The length of development time will vary depending upon field conditions. Water produced during development and sampling will be contained in 55-gallon barrels. GLDM will be responsible for the disposal of water and ai=:y recovered petroleum product. Prior to and following development, the depth to wtit!r will be mcasured with ar oil/water interface probe. Groundwater Sampling. Prior to sample collection, at Ieast three well volumes groundwater will be removed. A well volumc is defined as the amount of groundwater in the well casing and the sand pack with an assumed porosity of 35 percent. The pH and electrical conductivity of the water will be measured periodically prior to sample collection. All water samples will be collected, labeled, Stored, and transported as described in the groundwater sampling section above. The water samples will be submitted to BCAL for analysis "� of BTX and TPH by EPA Method 8015, modified, Extraction Method 5030.