SITE INFORMATION AND CORRESPONDENCE_CASE 2

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11 Mr. Verma -2- 3 October 1994 • For gasoline (TPH-g): representative composite samples prepared by USEPA Method 5030 and analyzed by GC/FID; • For diesel (TPH-d): representative composite samples prepared by USEPA Method 3550 and analyzed by GC/FID; • For Total Recoverable Petroleum Hydrocarbons (TRPH): analysis by USEPA Method 8020; • For BTXE: representative grab samples analyzed by USEPA Method 8020; • For Total Oil and Grease (TOG): USEPA Method 5520 E/F. In all cases, analytical detection limits shall be as close to the USEPA Method Detection Limit as possible. According to the Regional Board's Tri-Regional Board Staff Recommendations for Preliminary Investigation and Evaluation of Underground Tank Sites, these limits are: for TPH-g, 1.0 ppm; for TPH-d, 1.0 ppm; for BTXE, 0.005 ppm; and for TOG, 50.0 ppm. Most laboratories are able to meet these limits for most of these analyses. When the limits are not achievable by a laboratory, an explanation of the problem should be submitted with the laboratory data sheets. All peaks and trace-level detections should be reported, and laboratory scans should be presented with the other lab data. 2. Need for an Adequate Sampling Program. Satisfactory demonstration of hydrocarbon content of the soils depends on an adequate sampling program. For most of the soils at the land treatment facility, it is not sufficient to rely only results derived from the 1991 sampling. Additional samples are required from cells where there is reason to expect detectable levels of TOG, TRPH, or BTXE, or where no samples were taken earlier. It is not necessary to analyze for components that earlier samplings showed not to be present. It is necessary to analyze for all components that earlier samplings detected. The 23 August, 31 August, and 7 September submittals from your consultants all discussed by place of origin and cell location of storage (i.e., Schulte Road soils in cells 2 through 6, 10 through 18 and cell 20, and Schulte Road soils in cells 1,7, and 19; 11th Street and grant Line soils in cells 8 and 9). Different sampling programs were proposed for each category. Our comments follow the same format. Schulte Road Soils, cells 1,7 and 19: According to your consultant's submittals and information in our files, soils from the Schulte road site that appeared to contain higher levels of contamination were placed in cells 1,7, and 19. The 23 August submittal notes that these soils require additional sampling and analysis beyond that performed in 1991. We agree. The 7 September and 31 August submittals suggest that 5 samples be taken from the three cells before they are stockpiled. The 23 August submittal suggests seven samples. There are reportedly 3500 y3 of soil in the three cells. This computes to one sample per 700 y3 of soil. This amount of sampling is not sufficient for adequate characterization of the soils. In the 1991 sampling, which was done by a different consultant, no samples were taken from cells 1 or 7, and only one sample was taken from cell 19. Therefore we really know very little about the s oils in these three cells. Since cells 1, 7 and 19 supposedly