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In order to avoid cross-contamination of wells during the To minimize the potential for cross-contamination between
<br /> liquid-level measurement process,wells are measured in the air samples,the polyethylene tubing,if not sample
<br /> order of"clean"to"dirty"(where such information is dedicated,is thoroughly cleaned and rinsed.
<br /> available). In addition,all measurement equipment is
<br /> cleaned with solution and thoroughly rinsed with deionized Vapor samples are subject to very limited holding times,
<br /> water before use,between measurements in respective typically 48 hours. Thus,care must taken to avoid delays in
<br /> wells,and at the completion of the day's use. submittal of vapor samples to the laboratory. In the event
<br /> the vapor samples cannot be submitted to the analytical
<br /> laboratory on the same day they are collected,they are to be
<br /> SOP-10 temporarily stored in the dry,non-refrigerated,packed cooler
<br /> SOIL VAPOR SAMPLING:"TEDLAR"BAG SAMPLING until the very first opportunity for submittal well within the
<br /> TECHNIQUE/REMEDIATION SYSTEM SAMPLING required holding time,taking into account the time needed
<br /> for shipment to and receipt by the laboratory.
<br /> Prior to vapor sampling,the vacuum system must reach a
<br /> stabilized air flow(cubic feet per minute)for approximately
<br /> 15 minutes. Prior to the actual collection of the vapor SOP-11
<br /> sample,the following data is recorded:air flow,temperature, VAPOR SAMPLING:SUMA CANISTER SAMPLING
<br /> and pressure at collection ports and gauges. TECHNIQUE
<br /> The sampling equipment consists of a TedlarTm bag Prior to vapor sampling,the vacuum system must reach a
<br /> (available in 1,3,5,and 10 liter sizes),a diaphragm pump, stabilized air flow(cubic feet per minute)for approximately
<br /> and 3/16-inch-diameter polyethylene tubing(approximately 1 15 minutes. Prior to the actual collection of the vapor
<br /> foot long).The TedlarTm bag should be fitted with an integral sample,the following data is recorded:air flow,temperature,
<br /> valve for filling and sealing the bag after sampling.The and pressure at collection ports and gauges.
<br /> diaphragm pump inlet and outlet are fitted with 3/16-inch
<br /> hose barbs for attaching the sample tubing.Prior to vapor The sampling equipment consists of a sterilized,gas-tight,
<br /> sampling,the soil vapor source(vapor screen,vapor "Suma"stainless steel canister(available in one and six liter
<br /> extraction well or manifold,etc.)must be isolated for volumes),flow meter(if required,obtained and calibrated by
<br /> sampling.A sample label with the sample number and date the laboratory)and 1/4-inch-diameter polyethylene tubing
<br /> and time of sample collection is prepared and placed on the approximately 2 feet in length.
<br /> TedlarTA°bag.
<br /> The sampling ports are brass connections fitted with silicone
<br /> If the sample is being collected from an operating vapor septa and threaded into a tapped hole in the system piping.
<br /> extraction system,the target vapor manifolds must be set up The sampling procedure requires one end of the tubing to be
<br /> with sample ports that can be isolated without interrupting slipped over the sampling port and the other end over the
<br /> system operation. Prior to the actual collection of the vapor canister nozzle or flow meter(if required)to acquire an air-
<br /> sample,source data is recorded:air flow,temperature,and tight connection.The valve should be opened at this time
<br /> pressure;or,well identification number and depth interval of and the initial pressure should then be recorded to verify that
<br /> screen. the Suma canister is under vacuum. The Suma canister is
<br /> allowed to collect the soil vapor sample at a predetermined
<br /> Typical sampling ports consist of a 1/4—inch ball valve fitted duration. After the sample has been collected record the
<br /> with a 3/16-inch hose barb to form a slip stream from the final vacuum reading(approximately five pounds per square
<br /> sample source. inch gauge(psig))to ensure that the flow meter was working
<br /> properly,if applicable. Immediately following the sample
<br /> The sampling procedure requires one end of the tubing be collection,complete sampling information is recorded on the
<br /> slipped over the sample port hose barb and the other end label on the air sampling canister(e.g.,sample ID,date,
<br /> over the diaphragm pump inlet hose barb to form an air-tight time, location,and temperature). The sample is placed in a
<br /> connection. The sampling pump is then started and the non-refrigerated,dry cooler with sufficient packing to ensure
<br /> pump is purged for one minute with the vapor to be sampled. against damage during transport. Cooling samples will
<br /> cause condensation of any moisture within the air sample,
<br /> Following purging,the discharge of the pump is then thereby distorting laboratory analysis.
<br /> connected to the'Tedlar"bag using a section of 3/16-inch
<br /> tubing.The pump is restarted and the bag is opened and Suma canister samples are subject to hold times of typically
<br /> allowed to fill to approximately 3/4 of its capacity. Caution 30 days and with some compounds a more rigid hold time of
<br /> should be taken not to overfill the sampling bag. The sample 14 days is required.
<br /> is placed in a non-refrigerated dry cooler with sufficient
<br /> packing to prevent damage during transport. Cooling
<br /> samples will cause condensation of moisture within the SOP-12
<br /> sample,thereby distorting the laboratory analysis. SOIL VAPOR SAMPLING:SYRINGE SAMPLING
<br /> TECHNIQUE
<br /> For quality control purposes,a duplicate vapor sample
<br /> should be collected from each sampling port. This sample is Prior to vapor sampling,the vacuum system must reach a
<br /> then put on hold at the laboratory pending initial analysis. To stabilized air flow(cubic feet per minute)for approximately
<br /> ensure quality control and minimize the potential for cross- 15 minutes. Prior to the actual collection of the vapor
<br /> contamination prior to and during sampling,the diaphragm sample,the following data is recorded:air flow,temperature,
<br /> pump is thoroughly purged for approximately five minutes and pressure at collection ports and gauges.
<br /> with nitrogen or clean air(i.e.,compressed clean air). A
<br /> "blank"sample of the discharged air is captured in a'Tedlar" The sampling equipment consists of a clean,100cc,gas-
<br /> bag at the end of the purging procedure and may be tight syringe and silicone septa.
<br /> analyzed to ensure the purging was effective.
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