ARCHIVED REPORTS XR0004311 - Laserfiche WebLink

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Work Plan for Aftlonal Subsurface Investigation 7-Eleven Store#19976, 1399 North Main Street Manteca CA August 1,2000 Selected soil samples will be analyzed for BTEX, MTBE, and TPH-G by EPA methods 8020/8015 modified, and for oxygenates MTBE, TBA, DIPE, ETBE, TAME, ethanol, methanol, and 1,2-DCA using EPA method 8260 The groundwater monitoring well will be constructed of 10-foot long 2-Inch-diameter, Schedule 40 polyvinyl chloride casing with flush threads, and 0 020-inch-slot well screen Sand will occupy the annular space from the bottom to about two feet above the top of the well screen The sand pack will be sealed with about 2 feet of bentonite pellets saturated in place with neat-cement grout to about 10 inches below grade The wellhead is protected at grade by a locking,water-tight well cap and a traffic-rated street box (with watertight bolted lid)set in concrete The top of casing and rim of the new well box will be surveyed by a professional surveyor for horizontal position and elevation relative to mean sea level datum The groundwater monitoring well will be gauged and sampled in accordance with normal protocol during the next quarterly monitoring event following installation, unless otherwise directed by the San Joaquin County Public Health Services department Groundwater samples will be analyzed for BTEX and TPH-G using EPA Methods 8020/modified 8015, and for TBA, MTBE, DIPE, ETBE, TAME, ethanol, methanol, and 1-2 DCA by EPA Method 8260 Simulprobe Soil Sampling In order to determine if soil and/or groundwater are Impacted In the source area at depths of 30 to 45 feet, a Simulprobe soil boring will be advanced near existing monitoring well MW-1/MW1-A A Simulprobe utilizes a two-barrel soil sampling system which prevents soil-sample cross-contamination Continuous soil samples will be collected from 30 to 45 feet BGS The soil samples will be field-screened using an FID Based on FID readings, a minimum of three soil samples will be submitted to a state-certified laboratory for analysis for the same constituents as the soil samples collected from the monitoring well borings If groundwater is encountered in this depth interval, a groundwater grab sample will be collected and also submitted for analysis All sod cuttings and purge water generated during the monitoring and sampling event will be stored in Department of Transportation (DOT)-approved 55-gallon drums pending characterization and proper disposal