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Mov .24, 2008 4: 54PM Wright Environmental 832-5152 No . 6021 P . 3 1 <br /> way, it is our opinion that the issues may become resolved and an addendum may be submitted <br /> to continue with the NFAR. <br /> GeoProbe boring near MW-2 at depth interval of about 26- to 30-feet for a "deep" <br /> groundwater sample as discussed in the September 15, 2008 meeting; <br /> Groundwater monitoring wells sampling reduced suite of methods; <br /> a File and air photo search for potential up-gradient sources; <br /> a Soil sample collection and "deep" sampling of aquifer near MW-6 at depth interval of <br /> about 26-30. <br /> 2.0 Field Methods-Exploratory Boring <br /> Two exploratory borings will be drilled at a down-gradient location near MW-2 and up-gradient <br /> location near MW-6, within the sidewalk (public right of way) as shown on Figure 1. Drilling <br /> and well installation permits will be secured from EHD and if needed for the sidewalk drilling, <br /> and a utility clearance will be performed prior to doing the field work. The boreholes will be <br /> drilled with GeoProbe truck mounted drilling equipment. All drilling equipment and sampling <br /> tools will be cleaned prior to arriving, and before leaving the site. The probe will be advanced <br /> collecting continuous cores of soil in each borehole. The sampler will then be retrieved and <br /> dissembled, and if any soil filled acetate liner is retained for chemical analysis, it will be sealed <br /> with Teflon paper or foil and plastic endcaps, labeled, logged onto chain-of-custody forms and <br /> place in a chilled ice chest. Soil sample intervals retained for chemical analysis will be cut from <br /> the liners at depths of suspected contaminant presence. <br /> The boreholes will be logged using the Unified Soil Classification System under the supervision <br /> of a professional geologist. Additional lithologic information will be collected to describe the <br /> subsurface geology. The samples will be collected continuously, at intervals of obvious <br /> contamination and at stratigraphic features of interest. Upon completion of the borehole drilling <br /> and collection of water samples, the boreholes will be backfilled with grout, placed from the <br /> bottom to top of the borehole. <br /> 2.1 Field Methods- Groundwater Sampling Adjacent to MW-2 and MW-6 <br /> Each exploratory boring will be sampled. The sampling adjacent to MW-2 will sample the <br /> interval from about 26 to 30 feet. The sample depths adjacent to MW-6 are discussed in Section <br /> 2.3 below. The ground water samples collected from the boreholes using a HydroPunch tool for <br /> discrete sample collection. A brief summary of the sample procedure follows: The borehole will <br /> be advanced into the aquifer and to the desired depth. The HydroPunch tool is advanced to the <br /> depth and then opened by pulling the outer sleeve to expose a screened interval within the tool. <br /> Depth to'groundwater measurements will be made to the nearest one-one hundredth of one foot, <br /> and also checked for the presence of separate phase product. The water entering the HydroPunch <br /> screen will be sampled using a clean bailer, and carefully poured into the appropriate laboratory <br /> pre pared'containers with minimum cavitation. Each water sample will be labeled,logged onto a <br /> chain-of-custody form, and placed in a chilled ice chest on crushed ice for transport to the <br /> laboratory. <br /> Page 2 or 4 <br />