ARCHIVED REPORTS_PHASE II ENVIRONMENTAL SITE ASSESSMENT

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W GIlb • solathwesit, )[Inc. also in the vicinity of the maintenance shop, equipment wash pad and the welding shop, where the materials identified in the SPCCP have been commonly used. The one-foot sample from B-10, collected near the equipment wash pad, also contained elevated TPH-mo, O&G, zinc, TPH-d and TPH-g, consistent with the petroleum hydrocarbons that have been stored on site and that may be washed off the heavy equipment serviced in this area and potentially released to the surficial soils. Detections of TPH-d, TPH-mo, O&G and zinc in B-16 and B-17 may be attributable to maintenance and/or storage of old vehicles in this area as well as to shredded automotive debris,particularly in the area of B-16. Significantly higher levels of PCBs, petroleum hydrocarbons as well as many of the CAM17 metals were detected in the one-foot soil samples than in the five-foot samples, verifying that ongoing and historical site usage by Learner has adversely impacted soil quality on the property. The nature of the underlying soils and the characteristics of the contaminants have resulted in the observed concentration of contaminants in the near-surface soils of the site, as discussed further in Section 12.3. The chemical constituents identified in the soil by this Phase II ESA can be attributed to the documented historical and ongoing site practices of • Learner. 11.2 Groundwater Conditions Installation and sampling of permanent monitoring wells was not within the scope of this investigation. Due to the limits of the collection methodology, the grab groundwater samples were intended to be utilized as a preliminary screening tool and to assist in placement of any future monitoring wells. PCB concentrations in groundwater were detected only in borings that had detectable PCBs in one or both soil samples (see Figure 3). This may reflect a link between onsite activities and PCB contamination of the underlying groundwater. PCBs were found in the groundwater and one-foot soil sample taken in B-7 near the area of the August 2007 PCB release, but higher concentrations were found in soil and groundwater samples collected to the north in B-6 and to the east in B-13, suggesting multiple releases of PCBs. PCBs detected in groundwater from the east and northwest parts of the site also suggest multiple PCB releases have occurred on the Learner site. TPH-g was only detected in the groundwater sample from B-2 adjacent to the ST Services • Terminal site to the northwest, suggesting a potential offsite source of gasoline contamination; 704. PRI.05 26 July 21, 2008