IDIQ PWS Attch 5 Galena Background Info Key Docs BECOS vf3.docx

FA4890-06-R-9999

Attachment 1

APRIL XX, 2009

- final –

FA8903-20-R-0012

ATTACHMENT 5

Galena AK region - gALENA 5 December 2019

BACKGROUND INFORMATION AND KEY DOCUMENTS

The former Galena FOL is located in a remote area in the western portion of interior Alaska. Galena is only accessible by barge or plane. During the 2010 census, there were 470 residents in the Galena zip code. A federally recognized tribe, the Louden Tribal Council, is located in the community. The Galena area experiences a cold, continental climate with extreme temperature differences. The average daily high temperature during July is in the low 70s degrees Fahrenheit (°F); the average daily low temperature during January ranges from 10°F to below 0°F. Sustained temperatures of ‐40°F are common during winter. Extreme temperatures have been measured from ‐64°F to 92°F.

Conducting environmental cleanup activities at the former Galena FOL presents challenges due to the remote location and extreme climate. Lodging and vehicles are limited to rentals from local residents. There are also limited flights into and out of Galena. All equipment and materials need to be barged or flown in/out of Galena and barges only run in the summer. While some local labor is available to support cleanup work, the number is limited due to the overall size of the community. The work season at Galena is typically June through September; however, most remediation systems operate in the winter (September/October through April) when the groundwater level is lower. Timing is critical to ensure that plans are completed, and equipment/materials are scheduled for delivery in time to complete summer work.

Several sites are being addressed following the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) process. The remaining sites are being addressed under the Alaska Department of Environmental Conservation (ADEC) Contaminated Sites Program. The former Galena FOL is not listed on the National Priorities List (NPL). ADEC is the lead regulatory support agency. US EPA is consulted as needed particularly with regard to hazardous waste and underground injection control (UIC) wells, but does not participate in the Technical Project Team meetings and document reviews. Closure of sites follows ADEC regulations. ADEC Method 3 has been used to demonstrate the migration to groundwater pathway was not complete for most of the Galena sites that have achieved cleanup complete and site closeout (SC).

A thorough review of historic site data was completed in 2010 and investigation activities initiated to complete the evaluation of nature and extent at all sites at the former Galena FOL. The Preliminary Assessment was finalized in September 2011. Delineation of nature and extent of contamination was completed in 2010 and 2011 at some sites; however, supplemental data collection was recommended at many sites. The Air Force completed the supplemental site characterization and supplemental remedial investigation during the 2013 field season. Vapor intrusion (VI) evaluations have been completed for Building 1573 located within ST009, Building 1499 located within TU001, Buildings 1858/1859 located within CST014, and the airport terminal located within CB001. VI mitigation is a component of several remedies and documented in the Cleanup Plans and Remedial Action Work Plans (collectively referred to as remediation plans for this PWS).

A comprehensive groundwater sampling program was performed 2010 through 2014. Selective interim annual groundwater monitoring was conducted in 2018 by sampling a subset of the monitoring well network until remediation plans were finalized for all sites. Well inspection is required annually due to the potential for frost-heave. A hydrogeologic study including groundwater elevation monitoring and aquifer testing was completed in 2011. Groundwater elevation and flow direction is influenced by the Yukon River. The general flow direction is to the south, but reverses during river breakup and occasionally throughout the summer. The change in elevation can be up to 25 feet which has created a large “smear zone.” Silt layers in the vadose and smear zone add complexity to remedial actions. Non-aqueous phase liquid (NAPL) has been detected at some sites, but to-date has not been shown to be recoverable. Further evaluation is being conducted in 2020.

The Air Force also completed construction of a landfarm treatment facility in 2012 for the remediation of petroleum contaminated soil generated during remedial actions. A second treatment cell of equal capacity to the first cell was constructed at the landfarm facility in 2013. A Brown Bear tiller (owned by Ahtna) is currently used to till soil into windrows at the landfarm which was expanded again in 2018. The landfarm is located at the former runway at Campion Air Station, approximately 7 miles northeast of Galena, and operates from June/July through the end of August. Winterization typically occurs in September when temperatures drop and tilling is no longer effective. Successfully treated soil from the landfarm (to below ADEC Method 2 Cleanup Levels) has been transported to the nearby City of Galena landfill and stockpiled for use by the City of Galena as landfill cover. Soil with lower concentrations of chlorinated volatile organic compounds has been treated separately (tilling or SVE) and then transported to the landfarm to complete the remediation of petroleum.

The following is a list of key documents.

Records of Decision

Cleanup Plans

Comments

Remedial Action Work Plans/ Remedial Designs

Comments