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6.5.4 Purge Volume <br /> The sub-slab soil gas probes and the shallow soil gas probes will be purged of three purge volumes <br /> prior to sample collection using a gas tight glass syringe. Specifically, the mobile laboratory <br /> technician will use a gas-tight glass syringe to purge and sample the probes. The sample tubing <br /> will be connected to the syringe via a three-way valve. It is anticipated that one purge volume will <br /> be approximately 500 ml. <br /> 6.5.5 Soil Gas Sample Analysis <br /> The cumulative soil gas samples will be analyzed by an on-site mobile laboratory operated by TEG <br /> of Rancho Cordova, California, a laboratory certified by the State of California for analysis of soil <br /> gas samples. Samples will be provided to the laboratory under a sample chain of custody. <br /> 6.6 Proposed Groundwater Assessment for the Quality Cleaners <br /> Five proposed groundwater monitoring wells will be installed to assess groundwater quality and <br /> gradient pertaining to the impacts related to the Quality Cleaners. Initially, three groundwater <br /> monitoring wells (MW-2, MW- 4, and MW-5) will be installed in a triangular array so that an <br /> expedited survey of the three monitoring wells can be conducted. The results of the survey, <br /> available within approximately 48 hours, will be used to assess the flow direction of groundwater <br /> at the time the wells are installed. Based on the survey, the remaining two monitoring wells will <br /> be installed as proposed. If, however, the groundwater flow direction is other than to the north- <br /> northeast,the DTSC will be contacted so that alternative locations of the remaining two monitoring <br /> wells to be installed can be discussed. <br /> It is anticipated the bottom of the wells screens will be 20 to 25 feet bgs. The five monitoring wells <br /> as currently proposed are shown on Figure 10 and will be installed as follows: <br /> MW-1 will be installed approximately 40 feet southwest of the Quality Cleaners in the general <br /> area of Partner's 2015 groundwater samples from borings B3 and B4. This well is intended to be <br /> the upgradient groundwater monitoring well. <br /> MW-2 will be installed within the sidewalk immediately to the northeast of the Quality Cleaners <br /> in the general area of Partner's May 2015 groundwater sample from boring B5-GW. This well is <br /> intended to be a proximate downgradient groundwater monitoring well related to the anticipated <br /> source areas of the dry cleaning machine and boiler room. <br /> Sampling and Analysis Workplan <br /> Tracy Corners Shopping Center <br /> 3225 North Tracy Boulevard <br /> Tracy,California 95376 <br /> Partner Project Number SM14-129814 <br /> Docket Number HAS-VCA 14/15-108 <br /> August 15,2016 <br /> Page 26 <br />