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J , Following these developmental procedures, groundwater in each well will be sampled using a clean bailer The groundwater will be transferred to laboratory-sterilized glass vials, placed in iced storage, and transported directly to the environmental laboratory for analysis A Chain of Custody record will be completed by the geologist and submitted with the samples to the laboratory Groundwater samples will be analyzed by Matrix Environmental Laboratories, Inc for TPHg using EPA method 8015 (modified) and for BTEX using EPA method 602 Purged groundwater will be stored onsite in DOT-approved, 17-E, 55-gal drums Disposal options for this water depends on the results of the laboratory analyses Responsibility for disposal belongs to the site owner, however upon request by the owner, Walsh can take appropriate measures to responsibly dispose of the water Groundwater Probe Survey A minimum 9-point groundwater survey may be conducted surrounding the area of known contamination to Initially define the contaminant plume and select locations for drilling soil borings, installing monitoring wells, and collecting soil and groundwater samples Proper selection of soil and groundwater sampling locations is critical to successfully delineating the plume, and evaluating the potential public health risk and remedial alternatives for the site Groundwater sampling probes will be pushed hydraulically into the ground using a truck- or skid- mounted ram system Each probe will consist of a hollow steel rod with a retractable tip allowing groundwater to be withdrawn through the steel casing The groundwater sample will be recovered with a hand-operated pump into a connecting hose and transferred directly into laboratory-sterilized glass vials Water will be collected from the center of the water column to minimize potential volatilization during sampling procedures Laboratory analytical data from groundwater samples collected in this manner are not accepted by state and local regulatory agencies This approach however, is very cost-effective in plume delineation because it reduces the number of soil borings and monitoring wells necessary to fully delineate the plume, and because drill-cuttings are not generated using a geoprobe, plume delineation using a geoprobe can significantly reduce costs associated with soil containment and disposal Groundwater contaminant screening data will be used to select additional soil boring and monitoring well locations necessary to delineate and monitor the plume during remedial operations Vapor Extraction Well Construction At least one vapor extraction well will be constructed onsite to conduct a feasibility pilot test The well will be constructed of threaded PVC casing to a depth of approximately 20 ft The screen interval will consist of factory-perforated 0 10-in-wide slots and will extend from the base of the soil boring to a depth of approximately 5 ft below grade The annular space will be backfilled with washed pea gravel A 1- to 2-ft thick bentonite plug will be placed above the 9/14193 6 ]685-030 sew &Associates, Inc Environmental scientists and Engineers