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<br /> Stockton 99 Speedway
<br /> ' Preliminary Endangerment Assessment Workplan
<br /> April 12,2007
<br /> Following the Phase I ESA of the Stockton 99 Speedway, Kleinfelder conducted a limited
<br /> soil
<br /> assessment and test pit exploration that focused on the investigation of four areas of concern including
<br /> the Debris Area, Track Area, Dry Well Area, and Aboveground Storage Tanks (AST) Area. A total of 33
<br /> ` soil samples were collected from the four areas. Sampling was conducted using various methods
<br /> including hand angering and direct-push borings.
<br /> In addition, twelve test pits (TP1 through TP12) were excavated in the debris area located northwest of
<br /> the racetrack (Figure 3). The test pits were excavated to a depth ranging from approximately 6 to 15
<br /> feet.
<br /> Debris materials observed by Kleinfelder included I concrete asphalt, and wood,, p with. lesser
<br /> amounts of bricks, tires, hoses, sheet metal parts, wire, plastic, burnt wood, aggregate rock, concrete tile,.
<br /> and glass, etc. Review of Table 4 in Kleinfelder's Limited Soil Assessment and Test Pit Exploration
<br /> 4 Report, "Limited Soil Assessment and Test Pit Evaluation" indicates that for test pits TP1 through TP7,
<br /> the volume of debris ranged from 5 to 20 percent (Kleinfelder 2005). Based on the test pit findings,
<br /> Kleinfelder concluded that the vertical extent of the fill had not been defined beyond a depth of 15 feet in
<br /> the majority of the debris area assessed. Further, Kleinfelder concluded that the lateral extent of the till
<br /> had not been fully defined. Based on the test pit observations and topographical expression of the fill,
<br /> Kleinfelder estimated that the removal volume of fill is on the order of 61,000 to 91,000 cubic yards (yds3)
<br /> (Kleinfelder 2005b).
<br /> Kleinfelder collected a total of seven soil samples from the debris area including six, four-point
<br /> Q./ composites (from excavated material) and one discrete sample (TP2 at 15 foot depth). Five of the
<br /> composite samples and one discrete sample were analyzed for volatile organic compounds (VOCs),
<br /> semivolatile organic compounds (SVOCs), total petroleum hydrocarbons as gasoline (TPHg), as diesel
<br /> (TPHd), as motor oil (TPHmo), total recoverable petroleum hydrocarbons (TRPH), and leaking
<br /> underground fuel tank(LUFT) metals (cadmium, chromium, mercury, lead, nickel, and zinc).
<br /> With the exception of heavy metals (particularly lead), Kleinfelder noted that the results were
<br /> "unremarkable." The concentration of lead in the composite samples and the discrete sample ranged
<br /> from 273 to 1,610 milligrams per kilogram (mglkg). Kleinfelder concluded that based on these values,
<br /> some of the debris may be classified as a hazardous waste. Kleinfelder also noted that due to the
<br /> presence of building materials, the potential exists for asbestos to be present (Kleinfelder 2005b).
<br /> In November 2005, SGI conducted an investigation in the Debris Fill Area to further identify the lateral
<br /> and vertical extent of the fill material and to fill in data gaps identified in Kleinfelder's limited soil
<br /> assessment report noted above. Twelve test pits, SG1 through SG12, were excavated in the Debris Fill
<br /> C Area. During excavation, depth discrete soil samples were collected from each test pit from the fill
<br /> material and from the underlying native soil. Soil samples were analyzed for CAM 17 metals, and lead.
<br /> Selected samples were also analyzed for lead using waste extraction test (WET) and toxicity
<br /> characteristic leaching procedure (TCLP) methods to evalute waste disposal classification. In addition,
<br /> selected soil samples were also analyzed for organochlorine pesticides, petroleum hydrocarbons, and
<br /> VOCs. Results from this investigation were compared to the California Human Health Screening Levels
<br /> PEAWMOan.Finel.dw 2-3 The Source Group,Inc.
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