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Representative soil samples from SWMU No. 3 area were collected under the building
<br />floor at depths ranging between 12 and 35 inches below the concrete base (Samples
<br />#2-24, #2-36, #3-24, #4-24, #4-36, #5-24, #6-24, #7-24, and historical sample S-1-5
<br />and S-2-5). Results of the soil samples indicated that metals and VOCs were not
<br />detect above CHHSL values for commercial/industrial land use in this area. The
<br />boring locations from the August 2012 through November 2012 sampling activities are
<br />shown on Figures 2. Historical soil samples collected at the SWMU prior to use by
<br />OIT or AIT (S-1 and S-2) demonstrated no significant cyanide or metals.
<br />Soil samples were determined not necessary in the area of SWMU No. 4 because the
<br />SWMU was used as a temporary storage facility of dried sludge waste from the
<br />treatment operation were contained in 55 -gallon drums, and due to the six-inch thick
<br />epoxy coated foundation under the SWMU, impact to soils under the concrete was
<br />determined to be unlikely.
<br />Historical soil samples (Sample 131-5, B1-15, B1-20, S131-18, B1 -W, B2 -W, B3 -W, and
<br />MW -2), ranging in depth from 5 to 21 feet bsg, representative of SWMU No. 5 area
<br />were collected and reported in an October 1994 and August 1995 investigations by
<br />AIT. Results of the soil samples indicated that metals, SVOCs, VOCs, TO -G, PCBs,
<br />pesticides and/or cyanides were not detected above the reporting limits of the analysis
<br />or above the respective CHHSL values for commercial/industrial land use. Additional
<br />soil samples in the area of SWMU No. 5 were determined not necessary due to the
<br />six-inch thick epoxy coated walls and foundation, data results from historical soil
<br />sampling event, and the depth of the bottom of SWMU is approximately 20 feet bsg.
<br />Waste released would have directly migrated to groundwater (depth to groundwater is
<br />approximately 20 feet bsg) and have been detected down -gradient (north) in
<br />monitoring wells MW -1 or MW -2. Therefore, impact to soils under the concrete was
<br />determined to be unlikely.
<br />Representative soil samples from SWMU No. 6 area were collected under the building
<br />floor at depth of 12.5 inches below the concrete base (Samples #15-12 and #16-12). A
<br />soil sample (Sample MW1-20) was collected at a depth of 20 feet bsg, during a June
<br />20, 1995 investigations by AIT. Results of the soil samples indicated that metals,
<br />SVOCs, VOCs, TO -G, PCBs, pesticides and/or cyanides were not detected above the
<br />reporting limits of the analysis or above the respective CHHSL values for
<br />commercial/industrial land use. Additional soil samples in the area of SWMU No. 6
<br />were determined not necessary due to the six-inch thick epoxy coated walls and
<br />foundation, the data results from a historical soil sampling event, and based on the fact
<br />that the depth of the SWMU is approximately 20 feet bsg. Any waste released from
<br />SWMU No. 6 was designed to have directly migrated into SWMU No. 5 via floor drains.
<br />In the event that any waste may have been released through the bottom of SWMU No.
<br />5 or SWMU No. 6, waste would have directly migrated to the groundwater
<br />(approximately 20 feet bsg) and would have been detected in groundwater samples
<br />collected from wells MW -1 or MW -2 located down -gradient of SWMU No. 5 and SWMU
<br />No. 6. Therefore, impact to soils under the concrete was determined to be unlikely.
<br />Representative soil samples from SWMU No. 7 area, were collected from below the
<br />depth of the pipeline and in the area of the sump, ranging between 24 and 64 inches
<br />below the asphalt base (Samples #1-24, #7-24, #8-50, #9-64, #10-64, #6-24, and #7 -
<br />Statement of Basis for Former Advanced Interconnect Technologies, Inc. Facility Page 11 of 16
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