Laserfiche WebLink
WGIK <br /> Sounthwest, Inc. <br /> 12.0 CONCLUSIONS <br /> This Phase II investigation was undertaken to provide preliminary assessment of the most <br /> significant RECs identified at the Learner site in the Phase I ESA. The Phase II ESA has <br /> confirmed the presence of hazardous substances and petroleum products at the site under <br /> conditions that indicate impact from the historical and ongoing operations of The Learner <br /> Company. The level of diligence maintained during this investigation has generated data of <br /> sufficient quality to satisfy the objectives of the investigation and allow valid conclusions to <br /> be drawn. <br /> 12.1 Heavy Metals <br /> The Phase II investigation has determined that the shallow subsurface soils have been <br /> impacted with the CAM17 metals lead, zinc, copper, chromium and antimony at levels <br /> exceeding the TTLCs for classification as hazardous waste. Concentrations of cadmium, <br /> mercury and nickel in excess of reference levels were also detected in the shallow subsurface <br /> soils. Due to limitations of the groundwater sampling methodology and the data discrepancy <br /> resulting from testing some groundwater samples for dissolved metals and some for total <br /> metals, conclusions can not be made regarding potential impact to groundwater from metal <br /> • contamination. Further investigation regarding the impact of metals to soil and groundwater <br /> from site usage is recommended. <br /> 12.2 Storm Water Management Practices <br /> The results of this Phase II ESA investigation do not indicate that the practice of collecting <br /> storm water in former depressions and catch basins across the site has resulted in the <br /> concentration of contaminants in these areas. <br /> 12.3 Leakage from USTs and ASTs <br /> Documented TPH-d and TPH-g left in soil and TPH-d left in groundwater in the former UST <br /> location may be contributing to TPH-d and to a lesser extent TPH-g detections near the <br /> existing diesel ASTs and former diesel and gasoline USTs. Widespread detections of TPH-d <br /> in soils across the site cannot all be attributed to the UST/ASTs. However, TPG-d and TPH-g <br /> detections in the UST/AST area may be the result of releases from the former USTs or <br /> existing ASTs. TPH-d contamination was found in all but one of the groundwater grab <br /> samples collected during the Phase II. The fact that the highest concentration was found north <br /> of the former USTs where the highest TPH-d concentrations were detected during monitoring <br /> of the documented UST release indicates that contamination left in place continues to impact <br /> • the site. Further investigation of soil and groundwater conditions in this area and delineation <br /> 704. PRI.05 30 July 21, 2008 <br />