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24 May 2021 <br />Project No. 14-3002 <br />Page 20 of 23 <br /> <br />The lateral extent of TPH-d contamination in AOC2 is defined to the north and partially <br />defined to the east, however, the western and southern extent is undefined. It is likely that <br />the lateral extent to the east does not extend beyond the property boundary due to the <br />development of the adjacent property at 17100 Murphy Parkway (Figures 16 through 21). <br /> <br />Based on limited data points, the extent of dissolved TPH-d is defined to the north (B23, <br />B28 and B35), partially defined to the south (B48 and B67) and undefined to the east and <br />west. TPH-d concentrations were low and only two samples exceeded the MCL Priority. <br />Again, it is likely that the extent to the east does not extend far beyond the property <br />boundary due to the development of the adjacent property and the low concentrations <br />detected (Table 3 and Figure 22) <br /> <br /> <br />5.6. CONCEPTUAL SITE MODEL DISCUSSION <br /> <br />Investigations performed to date have identified four distinct buried waste cells at the Site. <br />The cells are comprised of glass processing waste from the former LOF/PNA facility to <br />the north. The waste cells range in aerial extent from 1,200 square feet in AOC1 (Waste <br />Cell No. 1A) to 10,000 square feet in AOC 2 (Waste Cell No. 2A), and from 6.0 feet thick <br />in AOC1 (Waste Cell No. 1A) to 9.5 feet thick in AOC1 and AOC2 (Waste Cell No. 1 <br />and 2). Additional and what appear to be isolated areas of buried waste were located in <br />the western half of AOC2. It is likely that one or more of these isolated waste areas is part <br />of a larger or an existing waste cell. The data collected indicates that the waste cells are <br />the source of COC contamination at the Site. <br /> <br />Waste Cells No. 1 and 1A (AOC1) are the remnants/continuation of the NWC and SWC <br />removed in September 2015 from the adjacent property to the east (17100 Murphy <br />Parkway). The NWC and SWC were removed up to the property boundary and waste <br />was observed extending on to the subject property. The total depths and aerial extents of <br />Waste Cells No. 1 and 1A correspond with the NWC and SWC and the waste cells have <br />been defined. The glass waste buried in AOC1 released COCs, including PCBs, dioxins, <br />and Pb, into the subsurface environment. The COCs are laterally and vertically defined, <br />largely confined to the waste cell limits, and have not impacted groundwater. Except for <br />PCBs and lead detected in one waste sample, COCs were detected below RSLs in AOC1. <br />Limited sampling was performed in the location of Waste Cell No. 1A, but the data is <br />consistent with results from Waste Cell No. 1 and confirmation data collected following <br />the removal of the SWC. AOC1 has generally been characterized. <br /> <br />Waste Cells No. 2 and 2A (AOC2) are located in the central and southern areas of the <br />Facility and were discovered during site investigation activities. Additional pockets of <br />glass waste were encountered in the Facility area that may be associated with larger <br />waste cells or the existing waste cells. An evaluation of the data and waste cells indicate <br />the buried glass waste is the source of the COCs detected in AOC2. A very limited amount <br />of waste was encountered in the northern portion of the Facility and COCs were generally <br />not detected in samples collected from this area of the Facility. COCs in AOC2 included