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Upon reaching TD,drilling fluid is circulated to remove cuttings. Vapor samples are subject to very limited holding times,typically 48 Selected casing is then run into the borehole and set to the desired hours. Thus,care must taken to avoid delays in submittal of vapor depth. Monitoring wells are cased with clean,threaded,factory- samples to the laboratory. In the event the vapor samples cannot be perforated and blank casing. The perforated interval consists of slotted submitted to the analytical laboratory on the same day they are casing,generally with 0.020-inch-wide by 1.5-inch-long slots,with 42 collected,they are to be temporarily stored in the dry,non-refrigerated, slots per foot. Centering devices may be fastened to the casing the packed cooler until the very first opportunity for submittal well within the ensure even distribution of fitter material and grout within the borehole required holding time,taking into account the time needed for shipment annulus. The well casing is thoroughly washed and/or steam cleaned, to and receipt by the laboratory. or may be purchased as pre-cleaned,prior to installation. All recoverable drilling fluid and/or cuttings are collected for temporary SOP-10 storage and disposed of properly pending analytical results. VAPOR SAMPLING:SYRINGE SAMPLING TECHNIQUE After setting the casing,sand or gravel filter material is poured into the Prior to vapor sampling,the vacuum system must reach a stabilized air annular space to fill from boring bottom to generally 1 foot above the flow(cubic feet per minute)for approximately 15 minutes. Prior to the perforated interval. A 1-to 2-foot-thick bentonite plug is set above this actual collection of the vapor sample,the following data is recorded:air filter material to prevent grout from infiltrating the filter pack. Either flow,temperature,and pressure at collection ports and gauges. neat cement,containing about 5 percent bentonite,or sand-cement grout is then tremmied into the annular space from the top of the The sampling equipment consists of a clean, 10occ,gas-tight syringe bentonite plug to near surface. A traffic-rated vault is installed around and silicone septa. each wellhead for wells located in parking lots or driveways,while steel "stovepipes"are usually set over wellheads in landscaped areas. The sampling ports are brass connections,fitted with silicone septa, and threaded into a tapped hole in the system piping. Samples are After installation,the wells are thoroughly developed to remove residual collected by inserting a clean syringe into the septum and the plunger drilling materials from the wellbore,and to improve well performance by actuated several times. Each syringe should be purged of three removing fine material from the fitter pack that may pass into the well. syringe volumes before collecting the sample. On the fourth purge,the Well development techniques used may include pumping,surging, plunger is extracted slowly until the syringe is filled with a gas sample, bailing,swabbing,letting,flushing,and air-lifting. All development then the syringe is withdrawn and the needle immediately plugged with water is collected either in drums or tanks for temporary storage,and a silicone stopper. The sample should be placed in a non-refrigerated, properly disposed of pending laboratory analytical results. To minimize dry cooler with sufficient packing to eliminate breakage during the potential for cross-contamination between wells,all development transport. Cooling samples will cause condensation of moisture, equipment is either steam cleaned or properly washed prior to use. thereby distorting laboratory analysis. Following development,the well is allowed to stand undisturbed for a minimum of 24 hours before its first sampling. For quality control purposes,a duplicate air sample should be collected from each port. This sample is put on hold at the laboratory pending Initial analysis. SOPS VAPOR SAMPLING:"TEDLAR"BAG SAMPLING TECHNIQUE Vapor samples are subject to very limited holding times,typically 48 hours. Thus,care must taken to avoid delays in submittal of vapor Prior to vapor sampling,the vacuum system must reach a stabilized air samples to the laboratory. In the event the vapor samples cannot be flow(cubic feet per minute)for approximately 15 minutes. Prior to the submitted to the analytical laboratory on the same day they are actual collection of the vapor sample,the following data is recorded:air collected,they are to be temporarily stored in the dry,non-refrigerated, flow,temperature,and pressure at collection ports and gauges. packed cooler until the very first opportunity for submittal well within the required holding time,taking into account the time needed for shipment The sampling equipment consists of a"Tedlar'bag(available in 1,3,5, to and receipt by the laboratory. and 10 liter sizes),a diaphragm pump,and 1/4-inch-diameter polyethylene tubing(approximately 1 foot long). SOP-11 VAPOR SAMPLING:CANISTER SAMPLING TECHNIQUE The sampling ports are brass connections,fitted with a silicone septa, and threaded into a tapped hole in the system piping. The sampling Prior to vapor sampling,the vacuum system must reach a stabilized air procedure requires one end of the tubing be slipped over the sampling flow(cubic feet per minute)for approximately 15 minutes. Prior to the port and the other end over the diaphragm pump to acquire an air-tight actual collection of the vapor sample,the following data is recorded:air connection. The sampling pump is purged for 1 minute with the flow,temperature,and pressure at collection ports and gauges. extracted vapor to be sampled. Following purging,the discharge of the pump Is then diverted through a two-way valve into the"Tedlar'bag, The sampling equipment consists of a sterilized,gas-tight,"Vacu- which should be filled to 3/4 of volume capacity. Caution should be Sampler'stainless steel canister,and 1/4-inch-diameter polyethylene taken not to overfill the sampling bag. The sample is placed in a non- tubing approximately 2 feet in length. refrigerated dry cooler with sufficient packing to eliminated damage during transport. Cooling samples will cause condensation of moisture The sampling ports are brass connections fitted with silicone septa and within the sample,thereby distorting laboratory analysis. threaded into a tapped hole in the system piping. The sampling procedure requires one end of the tubing to be slipped over the For quality control purposes,a duplicate vapor sample should be sampling port and the other end over the canister nozzle to acquire an collected from each sampling port. This sample is then put on hold at air-tight connection. The actuator on top of the canister Is depressed the laboratory pending initial analysis. To ensure quality control and for 10 seconds. At the end of the 10 seconds,the canister is minimize the potential for cross-contamination prior to and during disconnected from the tubing and the tubing is disconnected from the sampling,the diaphragm pump is thoroughly purged for approximately sampling port. Immediately following the sample collection,complete 5 minutes with nitrogen or clean air(i.e.,compressed clean air). A sampling information is recorded on the label on the air sampling "blank"sample of the discharged air is captured in a"Tedlar"bag at the canister(e.g.,sample ID,date,time,location,and temperature). The end of the purging procedure and may be analyzed to ensure the sample is placed in a non-refrigerated,dry cooler with sufficient purging was effective. packing to ensure against damage during transport. Cooling samples will cause condensation of any moisture within the air sample,thereby To minimize the potential for cross-contamination between air samples, distorting laboratory analysis, the polyethylene tubing,if not sample dedicated,is thoroughly cleaned and rinsed.