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Project Number 2098RV45 November 30, 2017 <br /> 4.5.3 Leak Test Protocol <br /> The leak check compound (isopropyl) will be enclosed within a tent-type structure at <br /> each potential leak point to keep the potential leak areas at saturated concentrations <br /> throughout the test. <br /> 4.5.4 Leak Test Analytical <br /> The chemical analysis of the soil-gas sample will include an analysis for the leak <br /> check compound. If a leak check compound is detected in the sample, the cause of <br /> the leak will be evaluated, determined and corrected through confirmation sampling. <br /> If the leak check compound is suspected or detected as a site-specific contaminant, a <br /> new leak check compound will be used. <br /> 4.6 Purge/Sample Flow Rate <br /> The sampling and purging flow rate of 100 ml/min to 200 ml/min was selected to <br /> minimize compound partitioning during soil-gas sampling. Samples will not be <br /> collected if field conditions, such as rainfall, irrigation, fine grained sediments, or <br /> drilling conditions affect the ability to collect soil-gas samples. If no-flow or low-flow <br /> conditions are caused by wet soils, the soil gas sampling will cease. In addition, the <br /> soil-gas sampling will not be conducted during or immediately after a significant rain <br /> event (e.g., 1/2 inch or greater), or onsite watering. <br /> If low flow conditions are determined to be from a specific lithology, a new SGA well <br /> will be installed at a new lateral location selected after evaluation of the site lithologic <br /> logs and/or in consultation with the CRWQCB. If moisture or unknown material is <br /> observed, installation of the VP well will cease until the cause of the problem is <br /> identified and corrected. If refusal occurs during drilling, an alternate, nearby VP well <br /> location will be selected. <br /> 4.6.1 No-Flow/Low-Flow Rates <br /> The purging or sampling flow rate of 100 ml/min to 200 ml/min is expected to be <br /> attainable in the lithology adjacent to the VP well. To evaluate lithologic conditions <br /> adjacent to the VP well where no-flow or low-flow conditions are encountered, a <br /> vacuum gauge or similar device will be used between the soil-gas sample tubing and <br /> the soil-gas extraction devices. A gas tight syringe may also be used to qualitatively <br /> determine if a high vacuum soil condition exists, which is based on whether suction is <br /> felt while the plunger is being withdrawn. <br /> 4.6.2 Purging/Sampling Rates <br /> E2C or GSI will conduct purging/sampling at rates between 100 to 200 ml/min to <br /> limit stripping, prevent ambient air from diluting the soil-gas samples, and to reduce <br /> the variability of purging rates. The low flow purge rate increases the likelihood that <br /> representative samples may be collected. The purge/sample rate may be modified <br /> based on conditions encountered in individual VP wells. Modified rates will be <br /> documented in the report of findings. <br /> 4.7 Soil Gas Sampling Protocol <br /> After the VP well is adequately purged, a soil-gas sample will be collected. A 1-liter <br /> Summa canister equipped with a flow restrictor will be used at each location. A flow <br /> regulator will be placed between the probe and the Summa canister to ensure the <br /> canister is filled at the proper flow rate. Summa canisters will be stored in such a <br /> E2C Remediation 12 <br />