Problems/Comments

In July 2013, the DEC received notification that contaminated soil had been encountered during the digging of a ditch by the City of Tanana along the roadway (spill #13309919502). Initial information collected indicated the area was previously used for storage of bunker-C fuel oil at a wood-stave tank farm and there was a historic spill when construction hit a fuel line that ran from the tanks to a header near the shore of the Yukon River. Contaminated material from the 2013 trenching was removed and transported to a liner near the landfill to undergo natural attenuation. The Tanana Tribal Council submitted a DEC Brownfield Assessment and Cleanup (DBAC) request in 2013 to assess contamination at the site. The applicants and the community are concerned there is possible contamination from past activities related to the former tank farm and old stave piping. In 2015 a Property Assessment and Cleanup Plan for the Tanana Community Hall was completed. Contamination at the site is believed to have originated from wood-stave fuel tanks that were on the property (possibly as part of Fort Gibbon)sometime prior to the early 1960s. Petroleum contamination, probably Bunker C, was observed in the surface soil on the south side of Lot 7 with diesel range organics (DRO)up to 122,000 mg/Kg, residual range organics (RRO) up to 139,000 mg/Kg, benzene up to 0.0591 mg/Kg, 1-methylnaphthalene, 2-methylnaphthalene, and benzo(a)anthracene were detected above cleanup levels. In 2017 a supplementary assessment on the Tanana Community Hall was completed under DEC's Brownfield Assessment and Cleanup Program. Consistent with the 2015 PACP report, apparent Bunker C fuel oil contamination was observed in the southern portion of the property boundary in a distinct 2 to 6 in thick layer at approximately 0.5 to 1.5 ft bgs. Analytical soil sampling within the visibly contaminated area identified concentrations of DRO, RRO, and six PAH analytes above ADEC SCLs. Analytical results showed no evidence of vertical migration of COPCs in the soil. Bunker C contamination appeared to be confined to the upper 2 ft bgs. Results from samples collected from the TWPs indicated no impacts to groundwater from historical releases of Bunker C contamination. The northwest and northeast corners of the visibly contaminated tar layer were delineated by S&W. PCBs were not detected in the soil samples collected from the visibly contaminated tar layer or from the location near First Avenue. Arsenic concentrations ranged from 4.67 gm/kg to 10.1 mg/kg. Data from five stream or pond sediment samples collected within a 9-mile radius of Tanana resulted in mean localized background concentrations for Arsenic of 9.2 mg/kg. The analytical data presented in this report, suggest that the site contains naturally occurring Arsenic concentrations above the ADEC Method Two SCLs. In 2019 a Supplementary Assessment on the Tanana Community Hall was finalized under DEC's Brownfield Assessment and Cleanup Program. The report described the field activities conducted on October 16-18, 2018 to characterize the nature of the Bunker C contaminated soil, and characterize the nature and extent of the hydraulic oil contaminated soil located on the parcel containing the Tanana Community Hall. These activities were used to inform remedial options in the Analysis of Brownfield Cleanup Alternatives (ABCA) report dated December 2018. In 2019 an Analysis of Brownfield Cleanup Alternatives was finalized under DEC's Brownfield Assessment and Cleanup Program. The possible actions included: No action; Disposal in Tanana City Landfill – Alternative #1; Offsite Thermal Remediation – Alternative #2; Landfarming – Alternative #3; and Bioremediation – Alternative #4.Both the no action and disposal in Tanana City Landfill have been ruled out due to lack of protecting human health, and contaminant concentration and leaching probability respectively. Offsite Thermal Remediation had the highest likely cost, and Landfarming and Bioremediation both recommend treatability studies. Ahtna Engineering incorporated comments from ADEC’s December 13, 2018 letter, and proceeded to discuss the options with the Community of Tanana. The remedial options were evaluated based on protection of public health, safety, environmental welfare and feasibility. All of the options were evaluated except no action and capping. A draft of the ABCA was posted on the ADEC website with a public notice on February 15, 2019. A 30 day public comment period was held from February 20, 2019 to March 22, 2019, with a public notice posted in the Daily News-Miner, and flyers posted in Tanana. A public meeting was held on February 26, 2019 at the Tanana Community Hall from 12-2 pm. Two comments were received and supported Alternative #2 Offsite Thermal Remediation. The final ABCA submitted on March 28, 2019 included the information pertaining to the public comment period, and public comments received.

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Contaminant Information

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Requirements

No associated sites were found.