Ordnance - Sites
Multiple investigations and actions have been completed on Adak to address potential ordnance. A brief summary of these efforts is provided herein. LUCs associated with ordnance sites are also identified.
The Explosive Ordnance Disposal Mobile Unit 11 Detachment Whidbey Island stationed at Naval Air Station Whidbey, Washington, conducted an ordnance survey in the known range areas of Adak as part of the OU A RI/FS (U.S. Navy 1996). The areas surveyed included SWMU 1 (Range Complex at Andrew Lake), SWMU 2 Minefield Area at Clam Lagoon (suspected Minefield), SWMU 8 (Andrew Bay Seawall), SA 93 (suspected Mortar Impact Area), and inhabited areas (downtown Adak area). The first four areas on this list were either physically investigated or visually inspected to determine the potential for ordnance contamination. In most areas, a hand-held magnetometer was used to identify subsurface metallic anomalies. The anomalies were then excavated in order to determine their nature. The inhabited areas of Adak were evaluated using existing EOD incident reports to determine the types and potential sources of ordnance items found in this area.
The 1996 Munitions survey indicated that the proposed minefield at the north end of Clam Lagoon (SWMU 2) may have contained mines placed during World War II. In 1996, following the Munitions survey, Supervisor of Shipbuilding, Conversion, and Repair, Portsmouth, Virginia (SSPORTS) performed an investigation of SWMU 2 using electromagnetic detectors in combination with wooden probes (SSPORTS 1999). An M2A1 anti-personnel mine was located, confirming that mines were actually present in this area. SSPORTS began clearance operations in mid-1998. The minefield clearance was completed in the fall of 1998.
A statistical investigation of the Downtown Area of Adak was performed by Foster Wheeler Environmental to provide information adequate for property transfer decisions. The Downtown Area was segregated into three areas designated as Priority I, II, and III Areas. These areas were given priority designation based on their likelihood of reuse. The Priority I Area consisted of the core reuse area. The Priority II Area consisted of the land south and east between the runway and core area. The Priority III Area consisted of the land north and west outside of the runway. The investigation of the Priority I and II Areas was accomplished in six phases: historical records/archive search, physical survey, surface clearance, geophysical investigation, grid/anomaly selection, and intrusive investigation. The historical records/archive search began January 10, 1997. The purpose of this effort was to locate and identify historical ordnance-related activities within the Priority I and II Areas. A physical survey was completed in January and February 1997 to establish a grid system for the subsequent surface, geophysical, and intrusive investigations. Surface clearance was performed using magnetic detectors to locate surface MEC items beginning in March of 1997. A geophysical investigation survey was performed in March through July of 1997 to collect subsurface anomaly data on each grid within the project area using a time-domain electromagnetic instrument and process the data to develop geophysical anomaly maps and target anomaly lists. Based on the geophysics data, areas for intrusive sampling were selected. During the intrusive investigation, a percentage of anomalies from each selected grid were excavated to identify each anomaly. All anomalies selected for identification were excavated and pertinent information was recorded for each anomaly excavated (to a maximum depth of 4 feet). During the investigation, 390 acres in Priority I Areas and 683 acres in the Priority II Areas, totaling 1,073 total acres, were surveyed and surface cleared. A total of 7,811 anomalies were identified, of which 4,481 anomalies were excavated. No Munitions items were found in the subsurface to a 4-foot depth. However, three ordnance items were found on the ground surface in the Priority II Area.
A statistical investigation of the Priority III Areas was performed to provide information adequate for property transfer decisions. As discussed for the Priority I and II Areas above, the investigation of the Priority III Areas was accomplished in six phases: historical records/archive search, physical survey, surface clearance, geophysical investigation, grid/anomaly selection, and intrusive investigation. The physical survey of the Priority III area was performed in October and November 1997 to establish a reference grid system for the subsequent MEC surface sweep, geophysical survey, and intrusive investigation. Surface clearance was conducted in two stages from October 15, 1997 to November 20, 1997 and from April 7, 1998 to May 16, 1998. Geophysical survey data were acquired from April 2, 1998 to May 9, 1998. The intrusive investigation was performed from May 21, 1998 to July 18, 1998. Additional investigations were performed in a potential minefield location in the Kuluk Bay beach area and in six suspected gun emplacements. During the investigation, 1,334 acres were surveyed. No MEC items were found on the surface. A total of 2,546 anomalies were excavated to a 4-foot depth, and 89 anomalies were excavated in the beach area. MEC items were found in three excavations.
In April 1998, the Navy expanded the scope of the MEC RI being conducted on Adak to include evaluation of newly discovered proposed minefield locations. Potential minefield locations on Adak were either investigated intrusively, investigated using geophysical and surface clearance data from previous MEC investigations, or by visual inspection. The investigation performed by Foster Wheeler Environmental, both archival and physical, revealed no evidence that defensive minefields were installed on Adak.
This investigation was intended to provide information adequate for property transfer decisions for areas north of the military reservation boundary, excluding the Downtown Area which was previously investigated. A statistical methodology was used to determine the 26 project sectors for evaluation based on geographic homogeneity, past use, and anticipated ordnance density. Historical archive records and documents were reviewed by MEC personnel and aided in identifying the sectors that were investigated during the 1999 field season. Each sector was analyzed to identify the hazardous terrain. Areas steeper than 27.5 degrees were excluded from the investigation area. Each sector was then evaluated statistically to determine the sampling area required to representatively sample the sector. Subsurface anomaly data were collected over the selected areas using a time-domain electromagnetic instrument (Geonics EM-61) and processed to develop geophysical anomaly maps and target anomaly lists. Target anomalies were chosen for intrusive investigation and the selected target anomalies were excavated in order to identify and record findings of geophysical targets within 4 feet of the ground surface. Mobilization to Adak began March 29, 1999. Geophysical data collection began April 15, 1999 and was completed on October 2, 1999. MEC intrusive operations began April 17, 1999 and continued until October 28, 1999. During the investigation, 26 sectors were surveyed including approximately 216 acres. A total of 7,243 anomalies were identified by interpretation of geophysical data, and4,991 anomalies were intrusively investigated. A total of 790 intrusively investigated anomalies (targets) were made up of one or more OE scrap items,48 intrusively investigated anomalies were abandoned MEC items,66 intrusively investigated anomalies were Munitions, and 20 Munitions or abandoned MEC items were visually discovered on the surface.
In July 1999, under the provisions of the existing FFA for the cleanup of the former Navy base at Adak Island, the Navy, EPA, and the State of Alaska formed an OU B Project Team. The OU B Project Team also includes USFWS, TAC, A/PIA and Adak community members. Because CERCLA does not include specific provisions associated with explosive hazards related to ordnance, the OU B Project Team was created to develop an investigation and cleanup approach for OU B consistent with the CERCLA process and acceptable to Adak stakeholders. The OU B Project Team developed a plan for investigating sites with potential MEC contamination that addressed the concerns of regulatory agencies as well as community members and TAC, the future landowner. This plan is formally referred to as the RI/FS Work Plan for OU B.
The Project Team developed a two-part evaluation of risk, based on an evaluation of hazard assessment approaches. Part 1 was considered the preliminary assessment, an initial screening to determine if potential sites should be retained for evaluation through the RI/FS process or designated as sites requiring NOFA and elimination from the RI/FS process. NOFA includes the continuation of the Adak Munitions awareness program and the inclusion of a deed notice pursuant to CERCLA 120(h)(3)(A)(i) or other suitable information on MEC in the BLM’s permanent file concerning the conveyance. Under Part 1, 183 ordnance sites were initially evaluated, and 78 of the sites were given a NOFA designation, as reported in the preliminary assessment report (U.S. Navy 2001b). During the preliminary assessment process, four new sites were added to the overall list.
Part 2 was the development of a site-specific explosives safety hazard assessment (ESHA) methodology to evaluate data provided by the RI process. The ESHA methodology is qualitative in nature, but makes use of both qualitative and quantitative inputs in a framework that results in a relative-risk ranking ranging from low risk (A) to extreme risk (E). Sites scored as an “A” or “B” were recommended for NOFA. Those scored with a “C” or “D” were recommended for further investigation or remediation. No sites received a score of “E.” In addition to potential explosive safety hazards, an evaluation of risk-based screening criteria for ordnance-related chemicals in soils was developed for sites on Adak where limited releases of ordnance-related chemicals may have occurred.
In 2001, OU B was subdivided into OU B-1 and OU B-2 to expedite transfer of real estate by placing a higher priority on completing the investigation and remediation of OU B-1 sites located within real estate planned for transfer to TAC. A total of 155 sites are addressed under OU B-1, 6 sites will be addressed under the formerly used defense site program, and the remainder are being evaluated as part of OU B-2.
OU B-2 addresses ordnance explosive safety hazards and human health and ecological risks associated with ordnance-related chemicals in areas identified for retention by the Navy. Of the 183 sites identified in the preliminary assessment, 59 were originally designated as OU B-2 sites. In addition, two new sites JM-01 and MM-23 were added after completion of the preliminary assessment. Therefore, a total of 61 sites were originally designated as OU B-2 sites. Twenty-three of these 61 sites were later transferred to OU B-1. Therefore, 38 sites are currently designated as OU B-2. Of the 38 sites, 16 sites were identified as NOFA sites in the preliminary assessment and thus did not require further evaluation in the RI. The remaining 22 OU B-2 sites are in the RI/FS stage of the CERCLA process (U.S. Navy 2004b). The 22 OU B-2 sites that are undergoing the RI/FS process are shown on Figure 8-2 and are within land transfer Parcel 4.