SITE INFORMATION AND CORRESPONDENCE_CASE 1

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Page 2 �,.. NOO, The hand auger sample HAI was placed five feet from the east wall, and therefore approximately five feet from the SBI boring termination. HAI through HA3 were advanced to a depth of 15 to 16 feet. This places the bone hole termination for hand augering one to two feet below the peals levels of contamination observed by the split spoon sampler used for SBI, (see Drawing I "Vertical Representation of SBI and HAI through HA3"). [It must also be noted that the water saturation, plasticity, and slumping movement of the soils encountered during the HA series made it difficult to isolate the bottom hole samples from cross contamination with the soils from the sidewalls above the terminus], We believe that SBI establishes the vertical extent of contamination. The indication from SBI is that hydrocarbon contamination peaks attin the water saturation zone interface,(between nine to fifteen feet), and diminishes below the groundwater level. The HA series of samples were taken within the depth where the peak hydrocarbon levels were observed by SBI, and HAI is approximately a five foot interval from SB1. We respectively submit that vertical extent was established by SBI and that the HAI through HA3 borings were advanced to an appropriate depth, consistent with the findings by SBI. We submit that no further sampling within the forklift shop is warranted. Regarding Selection of Proposed Boning Depth The RAH Environmental SB series of borings found only one location where measurable levels of hydrocarbons were detected in the soils, SBI. The data from SB1 suggests that the vertical extent of the contamination is eighteen to nineteen feet. The location of SBI is in the immediate vicinity of the plumbing from the historical tanks. Indeed the plumbing made a right angle directional change at/near SBI and a joint or connection would have been required at that location. If the SBI contamination was the result of a spill from the plumbing during tank removal cannot be confirmed or refuted. The spill during removal postulate is however a reasonable theory based on the available information. The goal of the sampling between SBI and SB7 is to evaluate soil and groundwater (for contaminant mass calculations)and soil physical characteristics(for treatability and groundwater risk analysis). A depth of 20 feet should adequately extend into native soils beneath the historical excavation. The SB 1 observation shows that, if contamination exists, it is found between nine to fifteen feet. I respectively submit that a hole termination of twenty feet is appropriate based on present data. A licensed geologist will employ field screening techniques during sampling,and if information warrants, a greater depth could be elected at the time of sampling. Bu= tyl Bob Bennett Tri Palley Growers En vironnvan l Services EXcws&!WA7 ACYDkGUVTs