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3. Scope of Work <br /> Roux will be conducting groundwater, soil vapor and indoor air sampling to address previously identified data <br /> gaps for environmental conditions at the Site. <br /> To assess the concerns regarding the uncertainty of MW-2s downgradient location to MW-1, Roux will install <br /> two temporary nested, monitoring wells at two depth intervals. Borings will be advanced to approximately <br /> seven feet below the observed groundwater table and a temporary polyvinyl chloride (PVC)well screen will <br /> be placed in the boreholes to facilitate groundwater sampling. The monitoring wells will be constructed using <br /> a hollow-stem auger rig with 6-inch diameter augers. The shallow prepack well will be constructed with a 10- <br /> foot screen interval placed between approximately 6 and 16 feet bgs and an associated riser pipe between <br /> approximately 0.5 and 6 feet bgs. The deeper prepack well will be constructed using similar methods upon <br /> encountering the water bearing zone below the shallow groundwater at approximately 10 ft bgs. <br /> Seven (7)groundwater samples will be collected from existing monitoring wells MW-1 through MW-5 as well <br /> as two temporary well locations. The monitoring wells will be developed by mechanical pumping until the <br /> turbidity of the purged water is reduced. During purging activities, water quality parameters including <br /> temperature, pH, specific conductance, turbidity, dissolved oxygen, and oxygen reduction potential (ORP) <br /> will be recorded using a YSI Multi System Probe, or equivalent. Purging will continue until water quality <br /> parameters stabilize. Purging and groundwater sample collection activities will be completed at flow rates of <br /> less than 200 milliliters per minute. <br /> A soil vapor assessment to determine data gaps in previous results. Samples will be collected from 21 <br /> existing soil gas probes (SG-14, SG-15, SG-16, SG-17, SG-18A, SG-19A, SG-14, SG-24, SG-25, SG-26, <br /> SG-27, SG-28, SG-29, SG-30, SG-31, SG-34, SG-35, SG-36, SG-37, SG-40, and SG-41) as well as the two <br /> temporary soil gas probes. <br /> Roux will advance two borings for the construction of permanent soil gas wells (SG-42 through SG-43)along <br /> the western property. Two additional soil gas probes(SG44-SG45)will be installed adjacent to the residential <br /> homes located south of the Site. Soil gas probes will be installed at a depth of 5ft bgs along boundary using <br /> a downhole rod to support the well tubing and probe in the borehole. Samples will be collected at least 48 <br /> hours after the installation of the new soil vapor probes. Roux will retain a California licensed drilling <br /> contractor to perform all subsurface drilling activities. <br /> Additionally, indoor air samples will be collected from the former Quality Cleaners Suite. Two indoor, one <br /> duplicate, and two outdoor samples will be collected over an eight-hour sampling period. <br /> If there are any changes with the scope, a revision of the HASP will be required to address any new hazards. <br /> 3989.0001 S.104/HSP Site-Specific Health and Safety Plan I ROUX 19 <br />