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Mr. Truong Mai - 2 - 22 March 1999 Detection limits for metals reported by the laboratory are another concern. These detection limits commonly exceed applicable water quality objectives. In this situation, meaningful comparisons between lab results and the criteria are not possible. For example, the MCL value for barium is 1.0 mg/1, but the detection limit for the WET tests was 5.0 mg/1. Other constituents may have applicable water- - quality objectives that are lower than their MCL values. The need for appropriate detection limits was emphasized in my 12 November 1998 comments on the work plan. The drilling mud samples were also analyzed for a variety of organic compounds. Diesel was commonly found in concentrations above 100 mg/kg with a few samples over 1,000 mg/kg. The potential for diesel from these wastes to degrade water quality should also be discussed. Lab reports for the groundwater samples showed exceedingly high concentrations of metals. The report notes that the water samples collected by the direct-push technique were not filtered before analysis. Future groundwater samples need to be filtered prior to analysis for inorganic constituents. The drilling mud wastes and any contaminated soils need to be classified under the applicable regulations. Waste classification may not be possible with the type and amount of data currently available. Additional waste and background groundwater analyses are needed to classify the waste. The nature and extent of groundwater contamination also needs to be examined. The condition of existing monitoring wells should be documented. If the existing wells are useable, they should be sampled. If the wells cannot be used, they should be abandoned in compliance with local standards. Many significant tasks need to be completed at this site before a remediation or closure plan can be prepared. Please submit a schedule showing tasks and due dates for field work, waste characterization, waste classification, and an evaluation of closure and remediation alternatives for the site. Field tasks should include all activities necessary to characterize the drilling mud, contaminated soils, and groundwater. The schedule is due 1 May 1999. Please note that Ms. Wendy Arano has been assigned as the Boards's new project manager for this site. If you have any questions, please call her at (916) 255-3140. STEVE E. ROSENBAUM Associate Engineering Geologist SER cc: Mr. Ron Rowe, Environmental Health, San Joaquin County Public Health Services, Stockton Mr. Gregory Brown, Bright and Brown, Glendale SER:ERM Report 3.19.99