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S Ms. Mary Meays Page 2 May 16, 1994 H will be collected to verify the results of the confirmation samples. These activities will be addressed in the additional investigation workplan, which will be submitted to PHS/EHD by May 25, 1994. SPECIFIC COMMENTS 1. Table I in the report incorrectly represented results of laboratory analysis of sample, E72N1, the lab reported 0.0380 xylene instaed of 0.380 xylene as the table indicated. The correct concentration value for xylene detected in sample E72N1 is 0.038 mg/kg. The value of 0.380 mg/kg reported in Table 1 is incorrect. The revised Table 1, which reflects the correct value for sample E72N1, is attached. 2. Tank #1 area a. Sample, W9S7, collected on October 7, 1993 at 6 feet, evidenced soil contamination; however, its location was not indicated on Figure 4. Soil sample location W9S7 was not a confirmation soil sample and was collected within the boundaries of the final excavation (note the reference point on Figure 4 from which all sample location distances were measured). This soil sample was collected during excavation activities to determine whether or not the extent of affected soils had been defined. After the sample result indicated the presence of chemicals above cleanup goals, excavation of soils continued in that area. The soils defined by sample W9S7 were excavated and treated; therefore, its location was not depicted on Figure 4. b. Sample, 1BN11 W16, collected on October 15, 1993 at 9.5 feet, evidenced soil contamination; however, its location was not indicated on Figure 4. Soil sample location 1BN11W16 was collected from the bottom of the excavation below the depth of the water table (this location should have been depicted on Figure 4). A revised Figure 4, which includes the location for sample 1BN11W16, is attached. Seepage of ground water was encountered at excavation depths below seven feet. Attempts to excavate soils from depths greater than 9.5 feet were unsuccessful (note that the approved Final Remediation Plan stated that soils near the clay/silt layer and sand layer interface (i.e., below the water table) would most likely be much too wet to excavate). Nonetheless, the analytical results for sample 1BN11W16 were 20 mg/kg TPH-gasoline, 0.043 mg/kg toluene, 1.077 mg/kg ethylbenzene, and 0.104 mg/kg xylenes. These results are below the cleanup goals of 100 mg/kg TPH-gasoline and very near the cleanup goal of 1 mg/kg total BTEX compounds established in the Final Remediation Plan.