Comments Dated: March 12, 2009

Transcription

1 Response to Comments from NJDEP s Radiation Protection and Release Prevention Programs Bureau of Environmental Radiation Sampling Summary Report, Former Dog Pound Area, Picatinny Arsenal Draft Final Document January 2008 Comments Dated: March 12, 2009 Bureau of Environmental Regulation (BER) staff reviewed the Army Corps of Engineer s (Corps) Draft Final Sampling Summary Report dated January 2008 for the Picatinny Arsenal former dog pound site. The site is located in Morris County, New Jersey. The report was prepared by Shaw Environmental, Inc. for the Corps. The purpose of this review is to confirm that the draft final sampling report provides the proper information to characterize the site and the support the conclusion to restrict access to the former dog pound area. The review also sought to verify that the June 1, 2006 NJ DEP comments were addressed regarding the Picatinny Arsenal, former dog pound site, April 2006 Characterization Survey and Sampling Plan. The report stated that the concentrations of radionuclides did not exceed the restricted use soil criteria listed in N.J.A.C. 7: or 15 pci/g of Th-232 which was taken from Table 3A. However, since there is no uncontaminated surface soil present, the correct table to use is Table 2A, Limited Restricted Use. If two feet of vertical extent are assumed, the soil criterion for Th- 232 is 3 pci/g. Therefore, there are concentrations of Th-232 that exceed the limited restricted soil criterion for Th-232 at this site. The report states that the thorium-232 levels are believed to be related to pulverized spent coal used as fill in this area or coal clinkers. Response: Exceedances of the limited restricted use standard for Thorium-232 will necessitate the use of appropriate engineering or institutional controls pursuant to N.J.A.C. 7: (a). Currently, engineering controls (i.e., a rope extending across the entrance road and a warning sign posted at the site entrance) are being used effectively to prevent site access. A feasibility study is being prepared for this site. The current practice of land use controls will be considered as an alternative in the feasibility study. Section states that the 2005 maximum gross alpha concentration of 5 pci/l in water did not exceed the Level of Concern (LOC) of 15 pci/l. However, because it exceeded the screening level of 5 pci/l, Ra-226 and Ra-228 radiochemical analyses should have been performed in sample DPMW-1. The report provided the results for Ra-228 (sampled in 2001), but not Ra-226. Please provide the results for Ra-226 in sample DPMW-1. Please note that this is the second time this information was requested. This was requested by NJ DEP in a June 1, 2006 letter. Response: The attached table includes the Ra-226 and Ra-228 results for sample DPMW- 1. Ra-226 was not detected in the sample. The report states several times that there is no LOC for surface water for radionuclides. This is not the case since there are surface water standards for radionuclides in N.J.A.C. 7:9B and are 1

2 the same as the Environmental Protection Agency s Safe Drinking Water standards. The Ra-226 result reported in a 2006 sampling event was for surface water and did not specify the analytical method that was used. Surface water samples should also be analyzed by a radiochemical method (e.g. Georgia Tech method). Response: The analytical method used for the surface water samples are noted in the attached analytical report. The surface water samples were analyzed by several radiochemical methods by a laboratory certified to perform the method, Severn Trent Laboratories (STL) in Earth City, Missouri. A summary of the various radiochemical analytical methods used for this investigation are presented on page 3 of 36 in the attached Analytical Report. Table 2-2 lists the MDCs for each radionuclide for a 3 X 3 NaI detector. The MDC of Uranium is listed as 81 pci/g when MARSSIM lists the MDC for Uranium as 80 for a 2 X 2 NaI detector. Please address how the gamma scan was able to detect Uranium at the desired level (the limited restricted use standard from Table 2A of 41 pci/g). Response: The uranium MDC value in Table 2-2 is stated incorrectly for a 3 x 3 NaI detector. The actual uranium 3x3 MDC is approximately 48 pci/g based on NUREG 1507 methodology. While it is acknowledged that the MDC is above the limited restricted use standard of 41 pci/g and that the gamma survey would have been unable to measure uranium levels with the 3X3 NaI detector, the gamma survey was only intended to provide screening level data. Follow-up soil sampling was conducted throughout this small narrow strip of land to provide definitive data to characterize the uranium concentrations. Considering soil sample locations were biased to the highest gross gamma results and additional samples were collected in non-elevated areas as another measure to assure the complete characterization of the site, the highest uranium sample result was only 5.32 pci/g. Therefore, additional sampling for uranium does not seem warranted. Additionally, the Army is not proposing unrestricted or limited restricted use for this site. Currently, engineering controls (i.e., a rope extending across the entrance road and a warning sign posted at the site entrance) are being used effectively to prevent site access. A feasibility study is being prepared for this site. It is expected that the current practice of land use controls will be maintained to restrict access to this site as the feasibility study is completed. The results reported in section 3.0 did not include the associated errors. Also, the text states that the samples were analyzed by Severn Trent (now called Test America), but the table indicates that Quantera Labs analyzed the samples. Please provide the laboratory data sheets for the radiological samples. Response: The analytical data report for the results reported in Section 3.0 is attached to this document including the associated uncertainties. 2

3 Conclusion The report concludes that the thorium concentrations do not exceed the restricted use standards. However, since there is no clean cover present, the limited restricted use standard is exceeded. Therefore, a remedial action workplan for this portion of the site will need to be submitted. Also, as stated above, radiochemical analysis of Ra-226 and Ra-228 shall be performed on well DPMW-1 and the laboratory data sheets shall be provided for all the results of the 2006 investigations. In addition, the MDC listed for Uranium should be rechecked to verify that the scan could detect Uranium above the limited restricted use standard. Response: Currently, a feasibility study is being prepared for this site, which will evaluate remedial alternatives for the radionuclides detected at the site. Radiochemical analyses for well sample DPMW-1 including Ra-226 and Ra-228 are attached. The MDC for Uranium was re-checked and found to be in error (see explanation above). The correct MDC for Uranium with a 3 x 3 NaI detector is 48 pci/g. 3

4 Table 1 Summary of Radiochemicals Analyzed for in Grounwater Sample DPMW 1 ProjectCode dsamplenumsampledate MediaCode AnalysisMethodCode AnalysisTypeCode CompoundCAS CompoundName UOM Concentration FinalQualifier EQL_RL SQL_MDL TotalUncertaintyRadiological PTA PHASE III 2A/3A RI DPMW-1 01/03/01 GW RAD U Total Uranium ug/l U PTA PHASE III 2A/3A RI DPMW-1 01/03/01 GW RAD Radium-226 pci/l UJ PTA PHASE III 2A/3A RI DPMW-1 01/03/01 GW 904 MO RAD Radium-228 pci/l 0.74 J PTA PHASE III 2A/3A RI DPMW-1 01/03/01 GW 9310 M RAD Gross alpha pci/l PTA PHASE III 2A/3A RI DPMW-1 01/03/01 GW 9310 M RAD Gross beta pci/l PTA PHASE III 2A/3A RI DPMW-1 01/03/01 GW AM-02 RAD Cesium-137 pci/l -0.2 U PTA PHASE III 2A/3A RI DPMW-1 01/03/01 GW AM-02 RAD Cobalt-60 pci/l -4.4 U PTA PHASE III 2A/3A RI DPMW-1 01/03/01 GW AM-02 RAD Americium-241 pci/l -4.1 U PTA PHASE III 2A/3A RI DPMW-1 01/03/01 GW NS-305 RAD Uranium-234 pci/l 0.44 J PTA PHASE III 2A/3A RI DPMW-1 01/03/01 GW NS-305 RAD Uranium-235 pci/l 0.06 U PTA PHASE III 2A/3A RI DPMW-1 01/03/01 GW NS-305 RAD U-238 Uranium-238 pci/l 0.23 (U)

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