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Ms. Margaret Lagorio, SJCEHD October 21, 2003 Joe's Truck Plaza Project No. 2033-15600-01 Work Plan for Additional Site Assessment Page 8 sampler ahead of the augers. After retrieving the sampler, the ends of the bottom-most, intact tube from each sample interval will be lined with Teflon T11 sheets, capped, and sealed. Each sample will then be labeled, placed in a resealable plastic bag, and stored in an ice-chilled cooler. The samples will remain chilled until relinquished to a state- certified analytical laboratory. Strict chain-of-custody procedures will be followed from the time the samples are collected until the time the samples are relinquished to the laboratory. Soil contained in the remaining brass tubes will be screened for volatile organic compounds using field instrumentation equipped with a photoionization detector (PID). Stratus will record PID readings, soil types, and other pertinent geologic data on the borehole log. A minimum of three soil samples from each boring will be submitted for chemical analyses: the sample exhibiting the highest PID response, the sample from just above first-encountered groundwater, and the sample from the bottom of the boring. Additional samples may be collected, at the discretion of the Registered Geologist or Engineer overseeing the project, for possible chemical analysis or physical testing. Shallow-Screened Monitoring Well Construction Shallow-screened monitoring wells MW-7 through MW-18 will be completed to a depth of approximately 15 feet bgs. The well screen will consist of 10 feet of 2-inch diameter, 0.02-inch factory slotted PVC, installed from approximately 5 to 15 feet bgs. A filter pack of LonestarTM #3 sand will be placed in the annular space around the well screen, from the bottom of the boring to a approximately 1 foot above the top of the screen. One foot of bentonite will be placed on top of the filter pack and hydrated with clean water, to provide a transitional seal for the well. The wells will be surged prior to placement of the bentonite seal to ensure the filter pack has properly seated. The remaining annular space will be backfilled with neat cement. A traffic rated vault box will be placed over the wells and a watertight locking cap will be placed on the top of the casing. The actual well construction may be modified in the field based on conditions encountered at the time of the investigation. Deeper-Screened Monitoring Well Construction Deeper-screened monitoring wells DW-1 through DW-7 will be completed to a depth of approximately 28 feet bgs. Because wells DW-1, DW-2, and DW-3 will be installed in areas where groundwater in the upper sandy zone is impacted, the borings used to install these wells will be advanced to a depth of approximately 18 feet bgs using 15-inch diameter hollow-stem augers. Steel conductor casing (9-inch diameter) will be installed in each boring, and neat cement will be placed in the annular space around the conductor casing. A minimum of 24 hours will be allotted for the cement to cure, then the borings for the well will be extended inside the conductor casing using 8-inch diameter hollow P:\Joe's Truck Plaza\Work Plans\Does workplan 102103.doc