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f lie Work Plan for Soil Excavation 4 The Southland Corporation,Store#20304 455 Grant Line Road CA January 28 1998 I I plan and in the crass-sections to show the soil sample locations Proposed sampling locations are shown on Figure 2 A total of eight floor/wall samples are proposed based on the extent of excavation Sail Stockpile Soil generated during excavation will be stockpiled on and covered with 6 and plastic at a location to be determined by the manager of the 7-Eleven store,and based on vehicular traffic flow Stockpiled soil Welt be sampled at 18 inches below the surface of the stockpile The samples collected from the stockpile will be composed of four discrete sleeve samples that wnll later be combined into one composite sample in the laboratory for analysis of TPH-G, BTEX and total lead for charactenzation pnor to disposal Once stockpiled soil has been profiled, manifests will be prepared,and the soil loaded and transported off site by a state-certified waste hauler for disposal at an approved facility Excavation Backfill After sampling the walls and floor of the excavation,imported pea gravel will be backfilled from the base to one foot above the water table(approximately 4 feet BGS) If petroleum hydrocarbons are detected into the northern edge of the excavation, oxidation releasing compound (ORC) material will be applied to the soil while backfilling Crushed base rock will be imported and compacted to 95 percent above the pea gravel followed by 4 to 6 inches of asphalt Groundwater Monitoring Well Installation During backfilling activities,two new groundwater monitoring wells will be installed in the northern (downgradient) part of the excavation to document the condition of the groundwater after soil excavation The wells will be constructed of 2-4nch diameter Schedule 40 poly mnyl-chloride (PVC)casing with flush threads and 0 020-Inch-slot well screen Each well screen will be installed from approximately 3 to 10 feet BGS A sand filter pacts will be placed to a maximum height of 1 foot above the top of the well screen One foot of hydrated bentonite will be added as a seal,followed by a neat-cement grout to grade The wellheads will be protected at the surface by a locking,expandable caps and traffic-rated street boxes (with watertight bolted lid)set in concrete The newly Installed wells will be monitored and sampled along with the existing site-related wells during the first quarter 1998 TASK 3: REPORT PREPARATION Fluor Daniel GTI wnll prepare a report summarizing the remediation activities detailed above The report will document the methods and results of the work,summarize laboratory analytical results,and include appropriate maps and cross-sections Historical laboratory data of groundwater and soil will be submitted 04%VW,P LTR souniLAND FLUOR DANIEL GTI