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California Regional Water Quality Control Board Central Valley Region Steven T.Butler,Chair Winston H.Hickox Gray Davis Secretaryfor Sacramento Main Office Governor Environmental Internet Address: http://www.swrcb.ca.gov/—rwgcb5 Protection 3443 Routier Road,Suite A,Sacramento,Califomi Phone(916)255-3000•FAX ) Mr. Carl Lang � � 18 November 1999 U.S. Army Corp of Engineers NQv 2 41999. A��N Sacramento District, CESPK-PM-H atPL'c�t 1325 J Street, 12th Floor v,RUw\J\t`SFRV1GtS Sacramento, CA 95814-2922 FIELD SAMPLING PLAN, REMOVAL OF CONTAMINATED SOIL, NAVAL COMPUTER AND TELECOMMUNICATIONS STATION(NCTS), SANDIEGO DETACHMENT, STOCKTON We have reviewed the Field Sampling Plan, Removal of Contaminated Soil for the Defense Reutilization and Marketing Organization(DRMO) site at NCTS, Stockton(Rough and Ready Island), dated 1 November 1999. The Plan was prepared by Geofon, Inc. of Stockton, CA. The Plan includes a Field Sampling Plan, Site Safety and Health Plan, and Quality Assurance Project Plan. The spill is described as a area where a surplus milling machine was stored, dismantled, and torch cut in the DRMO storage area. This resulted in hydraulic fluid stained soil,burned wood, melted steel, and debris in the area. The storage area is unpaved. Ground water in the area is at approximately 5 feet below ground surface (bgs). The spill left two oval shaped stained areas within a rectangular area about 15 feet wide and 20 feet long. Historical sampling has shown TPH-diesel detected at 16,000 mg/kg at the surface and 2,500 mg/kg at 1-foot bgs. Aroclor 1254 was detected at 2.3 mg/kg at the surface and 0.23 mg/kg at 1-foot bgs. Our review has discovered areas of concern that should be addressed prior to finalizing the Plan, as follows: 1. 2.4 Soil Stockpile Samples. One composite soil sample is proposed to be collected for each 100 cubic:yards of soil stockpiled. According to the dimensions of the excavation,which is 18 feet wide by 23 feet long and 2 feet deep, the total stockpiled soil is calculated to be only 31 cubic yards. Therefore, we recommend that two individual samples (not composited)be analyzed using EPA test methods specified by the landfill owner/operators accepting the waste. 2. 5.0 Sample Analyses. The Plan states that, "If any soil sample analyses show concentrations of metals exceeding 10 times the Soluble Threshold Limit Concentration (STLC) than a Waste Extraction Test(WET) will be performed using deionized water(DI)." The STLC for hazardous waste criteria should be used to determine the characteristics of the stockpiled soil for disposal. This analysis does not satisfy the needs of the Board with regards to water quality goals or the intent of the Plan which is to excavate soil until the area is determined to no longer be a threat to the waters of the State. In this respect, soil concentrations are no longer a threat to water quality when COCs are equal to or less than calculated naturally occurring background concentrations for metals. According to Table 1 of the Plan, the Army Corps of Engineers has the documentation in support of this analyses (see Target Levels), even though the Plan has not clarified how Target Levels were developed. The Army Corps of Engineers should refer to the Target Levels in Table 1 .California Environmental Protection Agency 0 Recycled Paper