Site Report: FAA Unalakleet - AWOS_DF
| Site Name: | FAA Unalakleet - AWOS_DF |
|---|---|
| Address: | East of North-South Runway and West of Kouwegok Slough, Unalakleet, AK 99684 |
| File Number: | 630.38.004 |
| Hazard ID: | 4232 |
| Status: | Cleanup Complete |
| Staff: | No Longer Assigned, 9074655229 dec.icunit@alaska.gov |
| Latitude: | 63.884944 |
| Longitude: | -160.791684 |
| Horizontal Datum: | WGS84 |
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We make every effort to ensure the data presented here is accurate based on the best available information currently on file with DEC. It is therefore subject to change as new information becomes available. We recommend contacting the assigned project staff prior to making decisions based on this information.
Problems/Comments
An environmental compliance investigation in 1992 identified surface staining. Soil samples documented petroleum contamination (BTEX and PAHs). Local residents have testified to leaking containers of glycols on site that may have caused some of the surface stains. This facility consists of an Automatic Weather Observing Station and a Directional Finder, and is located between the runway and Kouwegok Slough. Old maps show more infrastructure around this area than was located in the 1992 investigation. An old, empty aboveground storage tank has been stored on site after being taken out of service from another FAA facility nearby. Investigation to characterize this contamination is planned for summer 2007. On July 2, 2015, DEC finalized a Summary of Determinations: FAA Unalakleet – Direction Finder (DF) West Spill, DF East Spill, Range (SBRAZ) Transformer, and VORTAC Transformer. DEC reviewed the environmental records for the referenced sites in response to a Federal Aviation Administration (FAA) closure request letter, dated May 1, 2013. No further remedial action is required at these areas of concern. This site will remain active in the DEC contaminated sites program database, as there are separate source areas which have not been given a “cleanup complete” determination. Decommissioning activities completed at the DF site in 2017.
Action Information
| Action Date | Action | Description | DEC Staff |
|---|---|---|---|
| 4/26/2006 | Site Added to Database | Site added to the database. | Mitzi Read |
| 3/5/2007 | Exposure Tracking Model Ranking | Initial ranking. | Lisa Maserjian |
| 3/21/2008 | Update or Other Action | Received the Draft 2007 RI Report. DRO and RRO were not detected above the MTG cleanup levels. Arsenic was the only analyte reported above the cleanup criteria in spills near building 409. While it is unlikely that arsenic is from a spill, the lack of background data for comparison purposes does not allow arsenic to be eliminated as a potential contaminant of concern at this location. A background study to determine the mean arsenic concentration in native soils from the Unalakleet area is recommended. | Kim DeRuyter |
| 3/21/2008 | Update or Other Action | ETM ranking updated based on the 2007 RI. | Kim DeRuyter |
| 12/15/2008 | Update or Other Action | Received the revised RI dated August 2008. | Kim DeRuyter |
| 12/2/2014 | Update or Other Action | Assigned site to new PM for FAA Unalakleet. | Fred Vreeman |
| 5/28/2015 | Exposure Tracking Model Ranking | Initial ranking with ETM completed for source area id: 79775 name: East and West Spill Areas | Monte Garroutte |
| 7/2/2015 | Update or Other Action | The Alaska Department of Environmental Conservation (DEC) finalized a Summary of Determinations: FAA Unalakleet – Direction Finder (DF) West Spill, DF East Spill, Range (SBRAZ) Transformer, and VORTAC Transformer. DEC reviewed the environmental records for the referenced sites in response to a Federal Aviation Administration (FAA) closure request letter, dated May 1, 2013. In September 2007, arsenic (15.4 mg/kg), chromium (36.6 mg/kg) and mercury (0.0299 J mg/kg) were the only COCs detected above method two cleanup levels at the DF West Spill site. DEC has determined that the mercury and chromium concentrations will be considered de minimis, and the arsenic may be attributed to naturally occurring background concentrations. Petroleum related contamination is below Method 2 Table B levels. At the DF East Spill site, samples were taken in 2007 and arsenic (14.4 mg/kg) and mercury (0.0410 J mg/kg) were the only COCs detected above method two cleanup levels. DEC has determined that the mercury concentrations will be considered de minimis, and the arsenic may be attributed to naturally occurring background concentrations. No further remedial action is required at these areas of concern. The site identified by the site number 630.38.004, with Hazard IDs 4232: FAA Unalakleet - AWOS_DF will remain active in the DEC contaminated sites program database, as there are separate source areas at each of these sites which have not been given a “cleanup complete” determination. | Monte Garroutte |
| 3/21/2016 | Site Characterization Workplan Approved | DEC approved the Work Plan Addendum, Decommissioning Infrastructure and Investigating/Remediating Contaminated Soil, FAA Unalakleet Station, Alaska. This work plan addendum reports findings of Phase 1 work that affect the execution of the second and third phases of work (Phase 2 and Phase 3) and describes the associated work. Phase 2 is scheduled to begin in late March 2016 and Phase 3 in June 2016. The purpose of the proposed work is to decommission and remove FAA infrastructure in the vicinity of Unalakleet that is no longer in use and to investigate/remediate contamination resulting from operations at the sites. Work was fully completed at the Direction Finder (DF), two ceilometers at the airport, and the Very High Frequency Omnidirectional Range Collocated Tactical Air Navigation (VORTAC) Drum Storage Area during Phase 1. Work remains to be conducted at four sites, including the Range Site (also referred to as the SBRAZ Site), Communication Transmitter (CT) Site, Visual Approach Slope Indicator (VASI), and Localizer (LOC). Phase 2 work includes 1) the removal of unused and associated debris from the Range Site and CT Site; 2) The excavation of petroleum-contaminated soil that exceeds DEC Method 2 Human Health cleanup levels from the Range Site; and 3) testing transformer oils for PCBs at the VASI and LOC locations. Phase 3 includes 1) Field screening and sampling for lead at the site of two fallen towers at the CT Site; 2) Sampling soil for presence of PCBs at the VASI and LOC locations if the transformer oil is positive for PCBs in Phase 2; 3) Excavation of PCB-contaminated soil at the CT site; 4) Monitoring of the tundra disturbance and surface water quality at the Range Site following the Phase 2 excavation and backfill. | Monte Garroutte |
| 11/6/2017 | Update or Other Action | Approved Decommissioning, Remediation, and Site Investigation Report 2017 addressing five areas of concern including the Range Site, Communication Transmitter (CT) Site, Very High Frequency Omnidirectional Range Collocated Tactical Air Navigation (VORTAC) Drum Storage Area, Visual Approach Slope Indicator (VASI), and Localizer. Site investigations led to remediation efforts at the Range Site and CT Site with 30 cubic yards and one cubic yard of soil removed, respectively. Petroleum contamination remains at the Range Site with concentrations of DRO ranging 263–151,000 mg/kg and RRO ranging 2,240–12,900 mg/kg, both results with silica gel cleanup. Lead contamination remains at the CT Site with the highest concentration at 56,900 mg/kg, in addition to minimal PCB contamination above cleanup levels (1.2 mg/kg). Contamination at the remaining AOCs is below cleanup levels. DEC concurs that additional work will be required at the Range Site and lead remaining at the CT will have to be addressed through remediation or ICs. | Gretchen Caudill |
| 2/21/2019 | Document, Report, or Work plan Review - other | DEC Approval of 2018 RA and RI for 2 sites - CT Towers and Radio Range Site. | Gretchen Caudill |
| 12/10/2020 | Cleanup Complete Determination Issued | The FAA Unalakleet AWOS_DF contaminated site has been issued a closure complete. The attached closure letter specifically applies to the remining open source area at this site, Building 409. No contamination has been documented at Building 409. | Kelly Walker |
| 12/10/2020 | Institutional Control Record Removed | Institutional Controls have been removed. | Kelly Walker |
Contaminant Information
| Name | Level Description | Media | Comments |
|---|---|---|---|
| Arsenic - Total | < Method 2 Most Stringent | Soil | Remaining Arsenic levels at DF West Spill are 15.4 mg/kg |
| Chromium - Total | < Method 2 Most Stringent | Soil | Remaining chromium levels at DF West Spill are 36.6 mg/kg |
| Mercury - Total | < Method 2 Most Stringent | Soil | Remaining mercury levels at DF East Spill are 0.0410 J mg/kg |
Control Type
| Type | Details |
|---|---|
| No ICs Required |
Requirements
| Description | Details |
|---|---|
| Advance approval required to transport soil or groundwater off-site. | |
| Movement or use of contaminated material (including on site) in a manner that results in a violation of the water quality standards is prohibited (18 AAC 70) |
No associated sites were found.