Naval Weapons Station Seal Beach Remedial Investigation at MRP Sites UXO1, UXO6, and AOC2. Restoration Advisory Board Meeting January 10, 2018

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1 Naval Weapons Station Seal Beach Remedial Investigation at MRP Sites UXO1, UXO6, and AOC2 Restoration Advisory Board Meeting January 10,

2 Presentation Topics MRP Sites at NWS Seal Beach Munitions safety MRP Site History Remedial Investigation Activities and Results to Date Project Status and Schedule 2

3 Munitions Response Program Sites UXO1 -Primer/Salvage Yard and 7 th Street Pond, one of the POLB Mitigation Ponds UXO6 -Westminster POLB Fill Area AOC2 -Explosives Drop Test Tower 3

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5 Seal Beach National Wildlife Refuge 5

6 RI Planning Documents Final Remedial Investigation Work Plan approved by DTSCand RWQCBon August 1, 2017 Sampling and Analysis Plan Quality Assurance Project Plan for munitions-related activities Geophysical Investigation Plan Environmental Protection Plan/Waste Management plan Biological Avoidance and Minimization Plan The Explosive Safety Submission (ESS) was approved December ESS Correction 1* approved July 2017 ESS Correction 2* approved November 2017 *Corrections are clarifications to the original submission. 6

7 Munitions Safety All site work is being conducted by UXO-trained technicians, and personnel escorted by UXO-trained technicians. Safety distance zones are established around each MRPsite during work activities that involve possible contact with munitions items. The safety distance zones for work along the northern and eastern portion of MRPSite UXO6 may encumber Bolsa Chica Road and nearby dwellings, and Westminster Blvd. However, the large munition that would create these zones was not found at UXO6 during the recent investigation. 7

8 Munitions Response Terminology Material Potentially Presenting an Explosive Hazard (MPPEH) -Material that, prior to determination of its explosives safety status, potentially contains explosives or munitions or potentially contains a high enough concentration of explosives that the material presents an explosive hazard. Munitions and Explosives of Concern (MEC) Munitions that may pose unique explosives safety risks, means unexploded ordnance (UXO), discarded military munitions (DMM), or munitions constituents (MC) present in high enough concentrations to pose an explosive hazard. Material Documented as Safe (MDAS) -MPPEHthat has been assessed and documented as not presenting an explosive hazard and for which the chain of custody has been established and maintained. This material is no longer considered to be MPPEH. Munitions Debris -Remnants of munitions (e.g., fragments, penetrators, projectiles, shell casings, links, fins) remaining after munitions use, demilitarization, or disposal. Other Debris -Debris found at MRPsites, but not related to munitions or range operations. Such debris includes, but is not limited to, rebar, household items (refrigerators, washing machines, etc.), automobile parts and automobiles that were not associated with range targets, fence posts, and fence wire. 8

9 Remedial Investigation Study Goals Characterize the nature and extent of munitions and munitions-related material, evaluate potential explosive hazards, and suggest further actions to mitigate potential hazards at each MRP site. Characterize the nature and extent of munitions-related chemical contaminants, assess potential risks to human and ecological receptors, and suggest further action to mitigate potential risks at each MRP site. 9

10 MRPSite UXO1-Primer/Salvage Yard and 7 th Street Pond From 1944 through the 1990s, area was used for storage related to rocket and projectile segregation, inspection, and repackaging, as well as bomb and rocket overhaul. Area divided into: Primer Salvage Yard 48 acre area that included ordnance depriming, disposal, and EOD safety demonstrations. 7 th Street Pond 39-acre tidal pond constructed by the POLB in 1989 as part of mitigation for construction of 147-acre Pier J Landfill. Restored 116 acres of wetland habitat within the Seal Beach National Wildlife Refuge. 10

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14 MRPSite UXO6 Westminster POLBFill Area 180-acre area that received about 330,000 cubic yards of soil excavated and transferred from MRP Site UXO1 during pond construction Approximately 3-5 feet of soil spread across the site Suspected munitions from UXO1may have been transported to the Westminster POLB Fill Area

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16 MRP Site AOC2 Explosives Drop Test Tower Approximate 0.15 acre site with a central 50-foot tower and concrete pad Used from 1955 to 1977 to perform free-fall and guided safety drop testing on fuzes, cartridges, experimental propellants, and other low-level explosive items. Located in the Seal Beach NWR 16

17 MRPSite AOC2 Explosives Drop Test Tower 17

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19 RI at MRP Site UXO1 Terrestrial Site Activities Completed to Date: Utility Location Surveys, August-September 2017 Location surveys to establish site boundaries, August-September, 2017 Detector-aided visual surface clearance, including the portions of the 7 th Street Pond exposed during low tide (shoreline and islands in the pond), September-October, 2017 Biological monitoring prior to and during vegetation reduction Vegetation reduction to allow for access for follow on investigations, October Buried quality control (QC) seed items Digital geophysical mapping (DGM), including the portions of the 7 th Street Pond exposed during low tide, October-November Investigation of a percentage of randomly selected metallic anomalies from the DGM survey to statistically represent the entire area, November, Soil sampling, December

20 MRP Site UXO1 Clearance and DGM 20

21 RI at MRP Site UXO1 Results of Terrestrial Site Activities Completed to date: DGMsurvey identified saturated response areas (SRAs) (high density anomaly areas) and dispersed anomaly areas Metallic anomalies were randomly selected for intrusive investigation in both areas. Intrusive investigation results: No MECwas recovered MPPEHitems consisting of 40 mm cartridge cases, 20 mm projectiles, M-32 training submunitions, flash tubes, various type fuzes and small arms ammunition. Soil sample locations were selected where MPPEHwas found and at SRAs (biased sampling), at random locations within the Former Depriming Area. All samples submitted for explosives, metals and perchlorate analysis. Samples collected from SRAsand the Former Depriming Area also submitted for PAH and TPHanalysis. Laboratory analysis and data validation in progress. 21

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23 MRP Site UXO1 MPPEH Items 23

24 MPPEHStorage Near MRPSite UXO1 24

25 RI at MRP Site UXO1 Aquatic Site Activities Completed to Date: Pre-work eelgrass survey Surface clearance along shoreline and islands during low tide Side scanning sonar and bathymetry surveys to identify possible underwater obstructions that could affect the path of the DGM survey platform, December 1-2, 2017 Aquatic DGM survey December 11-21, 2017 Biological monitoring during aquatic surveys 25

26 RI at MRP Site UXO1 Aquatic Site Activities Results to Date: Widely separated individual patches of eelgrass, density reduced from that observed during 2013 survey Survey work was modified to accommodate the presence of sea turtles MPPEH found along shoreline during low tide: 40 mm cartridge cases Aquatic DGMsurvey indicated high anomaly density, in the northern part of the pond. Low density in remaining areas. 26

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28 Surface clearance at 7 th Street Pond Shoreline at UXO1 28

29 7 th Street Pond DGM Results 7 th Street Pond DGMresults (separate file presentation) 29

30 Completion of RI Field Activities at MRP Site UXO1 Aquatic Investigation Activities to be Completed in January to March 2018: Investigate a percentage of randomly selected metallic anomalies from the DGM survey to statistically represent the entire area Biological monitoring Sediment sampling for explosives, perchlorate, metals and total organic carbon Surface water sampling for explosives, perchlorate and total and dissolved concentrations of metals during high and low tide Post-work eel grass survey 30

31 RI at MRP Site UXO6 Work Completed to date at MRP Site UXO6: Utility locate surveys, August-September 2017 Location surveys to establish site boundaries, August-September 2017 Detector-aided visual surface sweep of 180 acres of MRPSite UXO6, September 2017 Vegetation reduction to facilitate DGM survey, October, 2017 DGM survey of 180-acre area, November-December

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33 RI at MRP Site UXO6 Results of Investigation Activities Completed to date: No MEC found based on surface clearance MPPEHitems recovered during surface clearance included cartridge case base to 5-inch projectile, Mk 3 3-inch projectile, and several flash tubes. DGMsurvey results indicated moderate to high density of anomalies throughout UXO6 33

34 MPPEHFound During Surface Clearance at MRP Site UXO6 34

35 MRPSite UXO6DGMResults UXO6 DGM Results Figure separate file presentation 35

36 RI at MRP Site UXO6 Activities to be Completed at Site UXO6: Using the results of the 180-acre DGMsurvey, develop an RI Work Plan addendum that describes the approach for the selection and investigation of subsurface anomalies and the collection of soil samples. 36

37 RI at MRP Site AOC2 Activities Completed to Date: Utility location surveys, August 2017 Location surveys to establish site boundaries, August 2017 Detector-aided visual surface sweep of the entire site, September 2017 Vegetation reduction as needed, September percent DGMsurvey of the site, October 2017 Investigated a percentage of randomly selected metallic anomalies from the DGMsurvey to statistically represent the entire area, November 2017 Soil sampling 37

38 RI at MRP Site AOC2 Results of Investigation Activities Results of DGMsurvey of the site indicated mostly saturated response areas surrounding the base of the tower, with decreasing density of items with increasing distance away from the tower. Interference from the metallic tower structure resulted in halo surrounding the base. Intrusive investigation of selected anomalies: No MEC MPPEHitems consisting of four indiscernible fuzesand a 40 mm projectile. Soil samples were collected at dispersed MPPEHlocations and saturated response areas. Laboratory analysis and data validation in progress. 38

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40 Management and Disposal of Munitions-Related Items Safe to move munitions-related items were transferred to and stored in an ATFapproved storage magazine near MRPSite UXO1. Stored items were consolidated and destroyed in one event using controlled detonation disposal procedures on December 7, The remaining items were inspected and determined to be either material documented as safe (MDAS), or non-munitions related metal debris. MDAS has been containerized (4 drums to date) and will be shipped offsite to licensed demilitarization facility at the end of the project. Munitions-related items found during the aquatic investigation at 7 th Street Pond will be managed the same way. 40

41 Management and Disposal of Non-munitions Related Debris Items inspected and confirmed to be non-munitions related debris were segregated from MPPEHand MDAS Approximately 5,800 lbsof non-munitions-related debris taken to local recycler. This debris represents most of what is being recovered from the site. 41

42 Remedial Investigation Report Remedial Investigation Report will include: Field investigation results Results of munitions hazard assessment Results of human health and ecological risk assessments for chemicals in soil, sediment and surface water Recommendations for performance of feasibility study for remedial alternatives 42

43 Questions? 43