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Home My WebLink AboutDSHW-2025-000539 Northrop Grumman Systems Corporation Propulsion Systems 5000 South 8400 West Magna, UT 84044 January 13, 2024 8200-CY24-11 Mr. Doug Hansen, Director Utah Department of Environmental Quality Division of Waste Management and Radiation Control 195 North 1950 West P.O. Box 144880 Salt Lake City, Utah 84114-4880 Re: Northrop Grumman Systems Corporation, UTD001705029 (Bacchus) Response to Annual Groundwater Report Comments Dear Mr. Hansen: June 11, 2024, Northrop Grumman Systems Corporation (NGSC) received a letter from the Division of Waste Management and Radiation Control (the Division) with comments from the NGSC Bacchus Facility Annual Groundwater Report (DSHW-2024-006619). This letter in response to the Divisions comments. Please note that due to unforeseen circumstances and consistent with conversations between the Division and NGSC, most of the changes to the Annual GW Report will be addresses in reformatting future reports. The Division wrote: 1.General. The Report does not include a comparison of the sampling results to a screening level. Sampling results should be discussed in context of whether constituents have or have not exceeded the screening levels. It is noted that Module V.G.4 of the ATK Bacchus Permit refers to Corrective Measure(s) Completion Criteria, although it is unclear how these criteria are defined. Comparison of data to maximum contaminant levels (MCLs) and/or Environmental Protection Agency (EPA) Tapwater Regional Screening Levels (RSLs) should be conducted. As MCLs and RSLs are regularly updated, please use the current screening levels for comparison. Please revise the Report to include a comparison of sampling results to the screening levels. NGSC Response: Appendices of future reports will be updated to include the RSLs and/or MCLs. Northrop Grumman Systems Corporation Propulsion Systems 5000 South 8400 West Magna, UT 84044 The Division wrote: 2. Water Levels. The Report states that water levels or samples were not collected from the following wells due to the wells being dry or having too little water depth: GW-01, GW-02, GW-04, GW-16, GW-17, GW-19, GW-23, GW-25, GW-30, GW-31, GW-32, GW-33, GW-34, GW-35, GW-36, GW-54, GW-56, GW-66, and GW-68. Also, a sample was not collected at GW-69 due to an obstruction in the well. a. With wells GW-30 through GW-36 and GW-66 being dry or having too little water to collect samples in 2022 and 2023, the ATK Naval Industrial Reserve Ordnance Plant (NIROP) source area for the perchlorate plume may not be adequately monitored. Please discuss the uncertainties associated with understanding the plume dynamics due to lack of data and discuss what additional actions may be warranted to address this data gap. b. Wells GW-17 and GW-23 are sentinel wells located on the southern edge of the perchlorate plume. As GW-17 and GW-23 were dry during the 2022 and 2023 sampling events, the southern edge of the plume may not be adequately monitored. However, it is noted that GW-17 and GW-23 are located in an upgradient location. Additionally, a number of the dry wells are located in the southern portion of the plume. This southern portion of the plume also may not be adequately monitored. Please monitor the wells and constituent concentrations in these locations. If additional wells run dry or concentrations increase, additional actions may be required to address the data gaps. c. The obstruction in well GW-69 was reported in both the 2022 and 2023 reports. Please discuss whether the obstruction in well GW-69 was remedied. If the well obstruction was not remedied, please propose corrective action at this well to remedy the situation and allow for continued sampling at this location. NGSC Response: a. GW-66, and GW-20 and GW-68, are currently in the procurement process for a contactor to drill. It is anticipated that these wells will be abandoned and re-installed winter of 2024-2025 or spring of 2025. GW-30 and GW-36 will be abandoned and replaced…. As GW-66 is near GW-30 and 36 and within the same plume, GW-66 can help represent groundwater in that portion of the Facility until GW-30 and 36 are abandoned and replaced. Northrop Grumman Systems Corporation Propulsion Systems 5000 South 8400 West Magna, UT 84044 b. See the well restoration schedule in the section below. Anticipated groundwater well restoration (abandonment and replacement) schedule: 2025 – GW-020, GW-066, and GW-068 2026 – GW-030, GW-036, and GW-060 2027 – GW-017, GW-056, and GW-067 2028 – GW-022, GW-031, and GW-033 2029 – GW-023, GW-032, and GW-036 2030 – GW-019A, GW-025, and GW-035 2031 – GW-004, GW-016, and GW-034 2032 – GW-001 and GW-002. This schedule will restore wells along the northeast corner including the property line and the plume source along the south side at an even pace. When a majority of the wells in these two critical areas are restored wells from the northwest corner near Coon Creek will start getting worked into the schedule. These wells are adjacent to many other wells. Therefore, even with some dry wells in this area, there is a better understanding of the plume in this area compared to the two areas addressed earlier in the schedule. This schedule may be adjusted based on work in adjacent buildings and annual budgets. c. Attempts will be made to have GW-069 ready for sampling in 2025. The Division wrote: 3. Analytical Results. The analytical results for annual sampling are provided in Appendix A and Appendix B. However, the analytical reports detailing the sample analysis results and the laboratory quality control report are not included in the Report for either the Chemtech Ford Analytical Laboratory or the internal M-53 Analytical Chemistry Laboratory at Promontory. This information is necessary to verify the information contained in the analytical results tables. Please revise the Report to include the laboratory analytical reports and quality control reports. NGSC Response: M-53 Laboratory Quality Control Report is attached. The Division wrote: 4. QA/QC Results. The Report states that field blank (FB) 003 had a detection of “2-butiene” of 3.3 parts per billion (ppb). Appendix A indicates a sample result of 3.3 micrograms per liter (µg/L) for methyl ethyl ketone (MEK) associated with sample FB-003. However, MEK is also known as 2- Northrop Grumman Systems Corporation Propulsion Systems 5000 South 8400 West Magna, UT 84044 butanone. Please clarify what is meant by “2-butiene” was meant to be “2-butanone”, please reference this chemical as MEK to maintain consistency throughout the Report. NGSC Response: Future reports will be clearer and include discussions in the QA/QC Results Section. The Division wrote: 5. QA/QC Results. Four FB’s (FB-003, FB-007, FB-008, and FB-009) and three trip blanks (TB)(TB-004, TB-006, and TB-010) had volatile organic compound (VOC) detections. Detections in the FB and TB samples include acetone, “2-buteine” (see Comment #4), chloroform, 1,1-dichloroethene, trichloroethene, 2-nitropropane, ethyl acetate, and toluene. Detections in FB and TB indicate there may be a problem with sample handling or laboratory contamination. The Report states that there is a lack of correlation to the detections in the FB and the VOCs associated with the groundwater monitoring wells in the vicinity of the where the Fs were collected. Please discuss the likely source of the contamination detected in the blanks. NGSC Response: Field Blank (FB) 003 had detections of acetone at 23.6 ppb and Methyl Ethyl Ketone at 3.3 ppb. However, GW-87 was collected at the same location and had detections of chloroform at 5.0 ppb and trichloroethene at 11.4 ppb. Therefore, it is unlikely that VOCs in the environment near GW-87 influenced the detections. FB-007 had a detection of acetone of 13.1 ppb. FB-007 was collected at the GW-01 location. GW-001 was not sampled due to low water levels in the well. FB-008 had two J-flagged detections, chloroform at 0.4 ppb and chloromethane at 0.8 ppb. FB- 008 was collected adjacent to GW-28, which had detections of 10 compounds. Chloroform was detected at 6.5 ppb. However, due to the lack of correlation detections between FB-008 and GW-28, it is unlikely that any contaminants in the area influenced the samples. FB-009 had a detection of acetone at 15.0 ppb. However, GW-70, where FB-009 was collected had detections of 1,1-dichloroethene, chloroform, and trichloroethene. Therefore, it is unlikely that contamination in the area around GW-70 influenced the analytical results. TB-004 had a J-flagged detection acetone at 8.2 ppb. TB-006 had J-flagged detections of both 2-nitropropane at 1.5 ppb and ethyl acetate at 0.7 ppb. TB-010 had J-flagged detections of acetone at 9.0 ppb, 2-butiene at 2.8 ppb, and toluene at 0.7 ppb. Northrop Grumman Systems Corporation Propulsion Systems 5000 South 8400 West Magna, UT 84044 As these Filed Blanks have no correlation with groundwater samples collected at the same locations, and trip blanks which remain sealed during transport, it is likely the contamination is due to lab error. The Division wrote: 6. QA/QC Results. The third paragraph states that all duplicate sample results were within range of the associated well. Please include the relative percent difference (RPD) between the original and duplicate sample results. The RPD should be compared to project specific requirements found in the ATK Quality Assurance Project Plan (QAPP) to determine whether the duplicate sample results were within range or require qualification. NGSC Response: Duplicate samples were collected from wells GW-12, GW-15, GW-42, GW-43, GW-49, GW-54A, GW-58, GW-65, and GW-71. All duplicate sample results were within range of the associated well. The table below shows the relative percent difference (RPD) between the sample of record and the blind duplicate. The acceptable RPD, according to the Division approved NGSC Bacchus Quality Assurance Project Plan is 30%. Well Chloroform Perchlorate GW-012 0.5 19 GW-697 0.4 19 RPD 22.2% 0.0% GW-043 2.2 74 GW-698 2 70 RPD 9.5% 5.6% GW-054A 2.3 13 GW-699 2.6 13 RPD 12.2% 0.0% GW-065 0.7 11 GW-700 0.7 9 RPD 0.0% 20.0% GW-049 1.1 51 GW-701 1.1 49 RPD 0.0% 4.0% GW-015 9.4 8 GW-702 8.8 9 RPD 6.6% 11.8% GW-058 0.4 ND GW-704 0.4 ND RPD 0.0% -- Northrop Grumman Systems Corporation Propulsion Systems 5000 South 8400 West Magna, UT 84044 The Division wrote: 7. QA/QC Results. The fourth paragraph states that conductivity was the only analysis that was outside of the holding time. However, based on the AQS Data Validation Report for Sample Delivery Group (SDG) 2308011, the holding time exceeded method limits for perchlorate in samples GW-086 and GW-077. Additionally, the Report and the AQS Data Validation Report state that, “analysis in this SDG appear to have been conducted according to project and method requirements. With the data validation qualifiers applied, all data are acceptable for use.” Based on the holding time exceedance, the perchlorate results for GW-086 and GW-077 should be flagged as estimated. However, the results for GW-086 and GW-077 are not shown as flagged in Appendix B. Please flag all qualified data and revise the report to include narrative regarding the holding time exceedance for perchlorate. NGSC Response: Future reports will have clearly labeled flags such as those mentioned above. The Division wrote: 8. Table 1 – Annual Water Levels. Wells GW-14, GW-42, GW-43, and GW-46 have had a net change in groundwater elevation of 7.05 to 7.96 feet. Please discuss how this will affect groundwater sample collection in context of the well screen lengths in these wells. NGSC Response: GW-14 has a screen depth of 23 to 38 feet below surface. During the 2023 groundwater sampling the depth to water was 23.06. This means the water elevation is at the top of the 15-foot screen. GW-42 has a screen depth of 30 to 40 feet below surface. During the 2023 groundwater sampling the depth to water was 31.74. This means the water elevation is in the top 2 feet of the 10-foot screen. GW-43 has a screen depth of 36 to 51 feet below surface. During the 2023 groundwater sampling the depth to water was 32.26. This means the water elevation is approximately 4 feet above the 15-foot screen. Northrop Grumman Systems Corporation Propulsion Systems 5000 South 8400 West Magna, UT 84044 GW-46 has a screen depth of 55 to 70 feet below surface. During the 2023 groundwater sampling the depth to water was 51.45. This means the water elevation is approximately 3 feet above the 15-foot screen. The Division wrote: 9. Flow Areas. West Bacchus Area: The first paragraph states that contaminant concentrations have stabilized or decreased over the past several years and that groundwater concentrations can be found in an Excel spreadsheet provided with the Report Unless Appendices A and B are considered to be the referenced Excel spreadsheet, the Excel spreadsheet does not appear to have been provided with the report. Please include this information in a revised Report and/or clarify the statement. NGSC Response: A narrative discussing the concentrations and movement of constituents of concern will become a part of future reports. The Division wrote: 10. Flow Areas. Central and East Bacchus Area: The Report states that “it is reasonable to assume that GW-72 is near the maximum eastward portion of the VOC plume.” Based on the isoconcentration information presented in Plate 3 (trichloroethene), Plate 4 (1,1-dichloroethene), and Plate 5 (1,1,1-trichloroethene), GW-72 appears to be located north of the VOC plume. Although, according to information presented on Plate 7, GW-72 is within the area of the VOC plume. GW-72 is, however, near the eastward portion of the Freon 113 plume, as shown on Plate 6. Please revise the Report to clarify these discrepancies between the text and the Plates. NGSC Response: This narrative is not correct, and more clarity will be added in future reports. The Division wrote: 11. Corrective Measures Implementation Annual Update. a. Item number 5: The Report states that calculation of the perchlorate mass in the aquifer was not completed for 2022 due to issues with your modeler. The Report also states that a new Northrop Grumman Systems Corporation Propulsion Systems 5000 South 8400 West Magna, UT 84044 groundwater modeler will be brought up to speed on your model and calculations will be made in the future. It is noted that the perchlorate mass calculation was also not completed for 2023. Please discuss when the perchlorate containment mass is anticipated to be calculated. b. Table 3 includes information about the recommended remedy of “establishing an on-facility land use restriction for future groundwater potable uses” as groundwater use restriction is part of ATK’s future land management plan. The status of this remedy is listed as “in works.” Please provide additional information about this remedy, how it will be implemented and enforced, and the anticipated timeframe for completion. NGSC Response: NGSC will contract with Geosyntec or another contractor in 2025 to create a perchlorate mass calculation. Additionally, NGSC’s legal team will start work on land use restrictions for groundwater. The Division wrote: 12. Pilot Scale Injection – Monitoring Results. The Report states that 2023 perchlorate concentrations at GW-25A and GW-25B were 230 ppb and 2,230 ppb, respectively. However, according to the figures illustrating the concentrations for gW-25A and GW-25 are 2,230 ppb and 230 ppb, respectively – the concentrations associated with the wells were switched. Please revise the information in the narrative to reflect this information. NGSC Response: GW-25A and GW-25B had a perchlorate concentrations of 2,230 ug/L and 230 ug/L, respectively. The Division wrote: 13.Appendix A and Appendix B. Volatiles and Perchlorate Analytical Results Tables: The table reporting analytical results for the sampled wells is formatted in a manner that does not allow for efficient comparison of data within a single well, among wells, or across yearly reports for trending analysis. The data are sorted by analyte rather than by well. This table should be reformatted in a manner that allows the reader to quickly compare the data. The data Northrop Grumman Systems Corporation Propulsion Systems 5000 South 8400 West Magna, UT 84044 should instead be sorted by well, then analytes, then date. A possible format is provided below – however, you may develop your own: Analyte Screening Level MDL MRL 1,1,1-ABC MCL 5ug/L 0.6 ug/L 1.0 ug/L 1,1,2-ABD MCL 5 ug/L 4.4 ug/L 10 ug/L 1,2-CD MCL 2.5 ug/L 0.3 ug/L 1.0 ug/L TCE ETC X ug/L X ug/L Perchlorate ETC X ug/L X ug/L Well Sample Date Groundwater Concentration A-1 xx/xx/2023 2.3 15.7 4.1 Etc. Etc. A-2 xx/xx/2024 ND 5.2 ND Etc. Etc. A-3 xx/xx/2023 1.1 2.5 (CF) 0.6J Etc. Etc. A-4 xx/xx/2024 2.3 15.7 4.1 Etc. Etc. B-1 xx/xx/2023 ND 5.2 ND Etc. Etc. (CF)-Samples analyzed by Chemtech Ford ND-non-detect U-samples…. J-samples flagged as estimated Bold-Result exceeding Screening Level Please reformat the analytical results table to facilitate efficient comparison of data. Please include applicable screening levels for the constituents monitored for data comparison. Please see Comment #1. NGSC Response: Future reports will adopt a format as described above. The Division wrote: 14. Appendix D – Plates and Report Narrative. The isoconcentration maps provide a useful visualization of the plume size and concentration. However, the isoconcentration maps should be accompanied with Report narrative that discusses the status of the plumes and whether they are increasing, decreasing, stable, or migrating. Northrop Grumman Systems Corporation Propulsion Systems 5000 South 8400 West Magna, UT 84044 Please include a discussion of the status of the plumes related to the information presented in the isoconcentration maps. NGSC Response: Future reports will include a narrative of the information found on the plates. The Division wrote: 15. Appendix D – Plates. The isoconcentration maps should include concentration contour lines representing the screening levels of the constituents to aid in the visualization of the locations of screening level concentration exceedances in the plumes. To further aid in this visualization, a contrasting color for the contour line representing the screening level concentrations should be used, or each plate should list the groundwater standard in the key/legend. NGSC Response: Plates included in future reports will include screening level contour lines. The Division wrote: 16. Appendix D – Plate 2. Plate 2 lists the perchlorate concentrations for wells GW-074 and GW-075 as 16 and 24 µg/L respectively. However, Appendix B lists the respective concentrations as 6 and 22 µg/L. The concentrations listed on Plate 2 are 2022 sampling results. Please ensure that constituents concentrations listed on the isoconcentration maps are current concentrations and/or include the year that the concentration is associated with if current data is not available. NGSC Response: Plates on future reports will reflect accurate data. The Division wrote: 17. Appendix D – Plates 3-6 Plates 3-6 list the constituent concentrations in well GW-69 as non-detect (ND). However, an obstruction was reported in GW-69 and the well was not sampled. The information associated with GW-69 should be listed as not sampled (NS) rather than (ND). NORTHROP1 GRUMMAN I Northrop Grumman Systems Corporation Propulsion Sstcrns S000 South 8400 Wost Magna, UT 84044 Additionally Plates 2 and 3 list GW-27 as ND. Neither Appendix A nor Appendix B list sample results for this well. If this well was not samples, GW-27 should be listed on the plates as NS. Please revise the information on the isoconcentration maps for wells that were not sampled to reflect the current information as "NS". NGSC Response: Plates on future reports will reflect accurate data. The Division wrote: 18. Appendix D - Plate 7. Plate 7 lists a perchlorate concentration of 36 ppbfor well GW-02. However, GW-02 was reported as dry during the 2023 sampling event. This information included on Plate 7 should list GW-02 as dry and/or include the year that the 36 ppb is associated with since current data is not available. Please revise the isoconcentration maps to include the current data and include the associated date for historical data when current data is not available. Please include a discussion of the status of the plumes related to the information presented in the isoconcentration maps. NGSC Response: Plates on future reports will reflect accurate data. If you have questions, please contact me at (801) 251-2142. Sincerely, Blair G. Palmer Manager, Environmental Services Northrop Grumman Systems Corporation Cc: Karen Wallner Ethan Upton