SITE INFORMATION AND CORRESPONDENCE

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r Mr. Alfonso T. Jesena, Jr. - 2 - 9 March 2000 Draft Pistol Range Site Investigation Report NCTS, Stockton 4. The Navy speculates that various types of wood, including buildings and the wooden range walls/features, were treated with creosol or pentachlorophenol and lead. The report is not clear on which of these contaminants will be analyzed. Railroad ties and telephone poles may have also been treated with the elements hexavalent chromium, arsenic, and copper. Therefore, the Navy should sample all suspect wood and surrounding soil for all of the potential contaminants. The Navy should provide a table with all COCs and EPA test Methods with applicable detection limits. For purposes of comparing data to background, the Navy should also include the Background Screening Levels found in the Final Technical Memorandum Background Metal Concentrations and Ambient Pesticide Concentrations in Soil, October 1997. If a COC is above background, then WET analysis should be performed using deionized water. These values should then be compared to background soluble concentrations for WET metals. Please address these issues in the revised SAP. 5. Investigation derived waste (IDW) should not be placed back in the respective borehole. Material should be contained until results of soil analysis have been reviewed by all the responsible parties. Disposal options would then be determined based upon sampling results. The Navy should revise this section of the SAP to ensure proper analyses prior to evaluating disposal options. 6. Table 5 —Data Quality Objectives for Pistol Range Investigation, Parcel 151, Step 5 states that if the concentration of lead in soil samples collected from 42 to 78 inches bgs in the front berm is less than 1,000 ppm in soils, the volume of soil to be remediated will be calculated. Based on background screening levels, total lead should be screened to 20 ppm and WET at 31.7 µg/L. Therefore, if soil samples are equal to or greater than 20 ppm for total lead, then WET analysis should be followed and those results compared to 31.7 µg/L. Please revise the table and text in this regard. 7. Table 5 —Parcel 152 Survey, states that a site-wide bullet density action level,based on a conservative estimate of the bullet density that would cause no significant lead contamination of the habitat area soil. We assume that this level of significance is based on the 1,000 ppm level as above. The Navy should develop a decision rule, which is more conservative because of the screening level of 20 ppm for total lead. Please revise Table 5 to reflect a more conservative decision rule. 8. Table 5 —Parcel 152 Soil Sampling, Step 2. Why is the Navy not using the background screening level of 20 ppm for lead as the action level? Please clarify. 9. Appendix A, Field Sampling Summary Sheet appears to be left partially blank. Please revise Appendix A to include the missing information. 10. Please ensure that every figure has a scale.