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` KLEINFELDER ` contacted and said the EHD had concerns over potential chromium VI concentrations associated with the road base. 6. Groundwater at the site is approximately 20 feet below the ground surface (bgs) according to the San Joaquin County Flood Control District (SJCFCD). On February 2, 2005, three soil samples were collected from each of six locations (Ll through L5 and BGl) on the approximately 115,000 square foot lot used for truck trailer parking. The locations (L1 through L5) were randomly located throughout the lot in order to obtain representative samples of the site. The lot is covered with a base containing a mixture of gravels, cobbles, and pieces of crushed concrete roof tile. The pieces of concrete roof tile were estimated at approximately 25% of the base material in the locations from which samples were collected. The thickness of the base ranged from approximately six to nine inches, beneath which was a transition zone including soil with intermittent cobbles and concrete tile pieces estimated at a L thickness of six inches. The shallowest soil samples were collected at the interface between the two zones (Samples Ll-0" through L5-0"). A background sample was collected from a location (BGI) along the southwest perimeter of the site, where a trace amount of base material was noted scattered on the surface. In each sample location a cleaned shovel was used to dig to approximately two inches above the desired sampling depth. A stainless steel hand auger was then used to remove approximately two inches of soil to insure the samples collected represented ` the desired depths. Three samples were collected from each location(Ll through L5 and BGl) at approximate depths of 0 to 6, 12 to 18, and 30 to 36-inches below the parking lot base. One ` parent material sample Ll-PM (concrete tile) was collected from location Ll. The parent material was collected directly from the parking lot area. A sample (Ll-PM) of the ` parking lot material was collected at location Ll using a cleaned shovel. A s t he p arking 1 of material contained abundant cobbles and gravels, pieces of concrete tile were manually selected and placed in a plastic bag for the crushed/rinseate analysis of the concrete tile. The six shallow soil samples and rinseate of the parent material were analyzed for the following: �. • Hexavalent Chromium by EPA Method 7196 • Total Petroleum Hydrocarbons as referenced to diesel(TPH-D) by EPA Method 8015B V Hexavalent Chromium (Chromium VI) was not detected by the analytical laboratory from the five shallow soil samples collected from immediately beneath the parking lot base, the perimeter background sample, or from the rinseate of the parent material. TPH-D was detected in one of the five shallow soil samples (L2-0") collected from the truck trailer parking area with a reported concentration of 0.36 mg/1. TPH-D was also detected in the rinseate of the parent material collected from location Ll with a reported concentration of 0.91 L mg/1. TPH-D was not detected in the shallow perimeter soil background sample (BGl-0"). 52495.E01/ST05R540/FB:Iv Page 2 of 5 C 2005 Kleinfelder,Inc. May 27,2005