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Stantec PHASE 11 ENVIRONMENTAL SITE ASSESSMENT REPORT Field Activities March 31,2011 samples. The purge volume test was conducted at a flow rate between 100 to 200 milliliters per minute(ml/min). Disposable gas tight syringes were used to purge the soil vapor wells. Prior to using a syringe, a stopcock was placed on the syringe and the plunger on the syringe was drawn back to verify the syringe did not have a leak. To create the vacuum on the sample tubing for the purging of probe, the syringe is drawn back creating the vacuum on the sample point. 2.2.2.3 Leak Test Leak tests were conducted to evaluate if a good seal was established in the sampling train, ground surface, and probe interface. Leak tests were conducted at every vapor sampling point. Isopropyl alcohol was used as the leak check compound. Isopropyl alcohol was applied to clean rags and placed around all connections in the sampling train in order to evaluate potential leaks of ambient air into the sampling train. A shroud was placed over the sampling equipment during the sample collection. 2.2.2.4 Soil Vapor Purging and Sample Collection The soil vapor purge/sample flow rates were between 100 to 200 ml/min. This flow rate was used because it does not enhance compound partitioning during the soil vapor sampling and limits stripping, prevents ambient air from diluting the sample, and reduces the variability in purge rates, and is consistent with the DTSC Guidance for soil vapor collection. The soil vapor samples from boreholes SV-1 through SV-4 and SV-6 were collected in SUMMA® canisters. Nylaflow tubing was used to attach the soil vapor well to the flow regulator and vacuum gauge that were attached to the SUMMA® canister. The soil vapor samples were collected at a low flow rate consistent with Cal-EPA DTSC protocols. The SUMMA® canisters (the primary and duplicate sample) that were to be used on borehole SV-5 were defective and would not fill completely. As part of the trouble shooting in the field, the flow regulator and vacuum gauge were replaced however; the SUMMA®canisters still would not fill. The SUMMA® canisters were only '% full and would require significant dilution from the analytical laboratory to perform the analyses thereby raising the detection limits on the sample. In order to keep the detection limits as low as possible, the soil vapor samples from SV-5 were collected in 1-liter tedlar bags. A new disposable gas tight syringe was used to draw the sample from the soil vapor probe into the tedlar bag for analyses. The SUMMA®canisters and tedlar bags were placed in a cooler and transported via a courier to BC Labs under COC procedures. The soil vapor samples were analyzed for VOCs including both the halogenated and petroleum based VOCs using EPA Method TO-15. The soil vapor samples were not chilled and condensation was not observed within the sample containers. The soil vapor samples were run on a 10-day turnaround time. is\projects\c 1pine\lodi\report\lodi.svrpt.do" 2.4