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Arty �/ Mr. Jim Barton RWQCB March 29, 2013 Page 13 . a) The desired sampling flow rate is 100 mL per minute. This low flow will be indicated by the amount of time needed for the vacuum to decrease from approximately 28 in Hg to 5 in Hg. b) When the gauge nearest the SUMMA canister shows 5 in Hg,.close inlet valve (the same one that was open),then close valve on SUMMA canister. C) Detach SUMMA canister from pump plumbing and attach sampling label to the sample container prior.to delivery to the laboratory. d) If there is a duplicate sample: i) Close all valves. ii) Attach a fresh SUMMA canister to the Sample T arm. iii) Open the two valves connecting the SUMMA and pump (not the valve on the SUMMA'canister itself). iv) Start the pump and build vacuum to approximately 21.5 in Hg to conduct a leak test. . V) Turn off the pump, and observe whether vacuum is maintained at the maximum reading for 1 minute. (1) If vacuum decreases, find and correct the leak. (a) The connection to the SUMMA canister often leaks. (i) It is unlikely that further tightening will fix . the problem (brass connectors are easily over-tightened), so replace the canister. (b) The criterion for passing the leak test is 10 percent of the SUMMA vacuum or 2.1 in Hg. (c) Sample the duplicate by following the procedure above, beginning with Step 2. 4) Once sampling is attempted or completed, the drill string is tripped out to remove all sample tubing, the sample tip, and all the inner rods prior to advancing to the next sampling depth. Soil Sampling Borings will be continuously cored with core containment in clear acetate liners. Soil samples will be retained and submitted for possible analysis at five-foot intervals beginning at five feet bgs and continuing until groundwater is encountered. Samples will also be retained from soils having petroleum staining or odors and where major (silt to clay or clay to sand) lithological changes occur. Soil samples will be screened using a photo-ionization detector(PID)and reading recorded on the boring logs.