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r Work Plan-Soil and Groundwater Investigation New Jernsaletn School October 2G,1998 Page-3- The soil cuttings from the borings and steam cleaning effluent will be placed in 55-gallon druJns, sealed, labeled, and left on site pending laboratory analyses. Disposal of hazardous materials, if any, will be the responsibility of the property owner. V One groundwater sample will be collected from each borehole using a Hydropunch groundwater sampler. The Hydropunch groundwater sampler is designed to be hydraulically pushed into the aquifer at the bottom of a borehole to collect a groundwater sample from a discrete zone. The sampler utilizes a sealed, watertight, stainless steel sample chamber and PVC screen that is isolated from the surrounding environment as the sampler is advanced. When the desired depth for collection of a groundwater sample r is reached, the sample chamber is opened by pulling back on the body of the sampler, exposing the screen. When the screen is full, a small diameter stainless steel bailer is lowered into the push rod and a groundwater sample is retrieved from the sample chamber. The bailer sample will be inspected for free �.. product, odor, and sheen. The sample will subsequently be poured into laboratory-supplied containers. The soil and groundwater samples will be stored in a cooler chilled with Blue Ice and delivered within 24 hours of collection, under chair-of-custody procedures, to GeoAnalytical Laboratories, in Modesto, California (a California State Certified laboratory). The soil samples will be analyzed using U.S. EPA 4 Methods and California-approved methods following quality assurance measures. Laboratory analyses are discussed in Section 3.7. Upon completion of the drilling and sampling, the boreholes will be grouted to the ground surface with cement slurry containing approximately three to five percent bentonite. The slurry will be tremied into the borehole to avoid bridging. All decontamination rinsate produced during the fieldwork will be `r placed in a 55-gallon drum, sealed, labeled, and left on site pending laboratory analyses. 3.4 MONITOR WELL INSTALLATION V The monitor wells (MW1, MW2, and MW3) will be drilled by Spectrum Exploration. Tine proposed monitor well locations are shown on Figure 2, Appendix A. The monitor well boreholes will be drilled and sampled using the same procedures as for the soil borings. The boreholes will be drilled to a depth of approximately 23 feet bgs. 3.5 MONITOR WELL CONSTRUCTION The monitor wells will be constructed with 2-inch O.D., Schedule 40, flush-threaded, machine-slotted PVC screen (slot size 0.020) extending from a depth of approximately 8 feet to 23 feet bgs. A flush- threaded PVC bottom cap will be placed at the bottom of the screen. Blank PVC casing will be installed above the screen to the ground surface. The well casing will be stearin-cleaned on site prior to use. No glue or solvents will be used in the construction of the wells. y A sand pact: of 43 Monterey sand will be placed in the annular space to approximately one foot above the screen- Approximately two feet of bentonite pellets will be placed above the sand to form a protective seal. The bentonite will be hydrated using potable water. A seal of neat cement will be ' poured in the annulus from the bentonite seal to the ground surface and a locking, traffic box will be installed at the ground surface. The proposed well design is shown in Figure 3,Appendix A r h L� CONDOR it