| Action Date |
Action |
Description |
DEC Staff |
| 7/4/1994 |
Underground Storage Tank Site Characterization or Assessment |
SA1R; Thomas reviewed site assessent report: Three USTs removed, contaminated soils encountered and 140 yrds of soils removed and stockpiled offsite. Groundwater suspected; one tank had an open severed pipe in the sidewall below ground water. Pipes and island still in place. ADEC gave guidance in NOR letter. Requests some action this fall (complete pipe removal), the rest defered until spring. |
Former Staff |
| 7/15/1994 |
Leaking Underground Storage Tank Release Confirmed - Petroleum |
LUST Site created in CSP for source area ID 77764 ADD; Nenana Truck Stop, Former. File# 110.26.004 by Thomas. |
Former Staff |
| 7/15/1994 |
Site Added to Database |
|
Former Staff |
| 10/3/1994 |
Leaking Underground Storage Tank Cleanup Initiated - Petroleum |
LCAU; Thomas reviewed site assessent report: 140 yrds of contaminated soils removed and stockpiled offsite. ADEC requested treatment plan in its NOR letter. |
Former Staff |
| 10/3/1994 |
Update or Other Action |
NOR; Thomas sent NOR letter to Yutana Barge Lines, summarizing site conditions and requesting corrective action. Requested that they address: soil stockpile, pump island & lines still in ground, evaluate ground water water impact, evaluate residual soil contam, research hostory of facility, and address ASTs as necessary. |
Former Staff |
| 1/31/1995 |
Update or Other Action |
UPD; SITE SUMMARY: Abandoned USTs removed in 94. Soil and ground water impact remain insitu. Pumps still need removal. PRP will do Release Investigation in 1995. Contact them in spring and request work plan. Review file. One of removed tanks had underground severed pipe. |
Former Staff |
| 1/20/1997 |
Update or Other Action |
Sherwood Clouse and said site is cleaned. Also as talking said there was gw monitoring wells on site. Told him that was why it was still open. He'll call Clint Adler; Sherwood Claus; 907-832-5505 |
Former Staff |
| 11/20/1997 |
Update or Other Action |
ADEC sends Notification of Intent to Cost Recover Letter to Current Owner: YUTANA BARGE LINE DBA YUKON FUEL |
Former Staff |
| 2/27/2006 |
Update or Other Action |
Sent letter to Steven Wilson with Crowley Marine Services (new owner of site) requesting a release investigation for the site. |
Deborah Williams |
| 6/16/2006 |
Update or Other Action |
ADEC received a 2006 Release Investigation Workplan for the Nenana Truck Stop. SLR proposes to install five soil borings around the former excavation, pipeline and dispenser area and complete the borings as monitoring wells. Soil samples and groundwater samples will be collected. They propose to complete this work in June/July of 2006. |
Deborah Williams |
| 12/21/2006 |
Update or Other Action |
ADEC received the SLR report entitled 2006 Former Nenana Truck Stop Site Characterization and Monitoring Report. According to the report, soil and groundwater petroleum impact has not been completely defined at the site. Benzene contamination has been found in the former fuel island area and based on the sample results, it has not yet been delineated. At boring B-1/MW-1 which was supposibly located upgradient had benzene concentrations in the groundwater detected at a depth of 5 feet bgs. MW-5 which is located near the former fuel island also had benzene contamination. The other monitoring wells which were located to the north of the former fuel island and near the former UST excavation did not contain any contaminants above ADEC cleanup levels. Based on these results, SLR concluded that seasonal fluctuations of the Tanana and Nenana rivers change the groundwater gradient significantely. |
Deborah Williams |
| 3/21/2007 |
Update or Other Action |
Updated the GIS location from the GIS aerial photo map. |
Deborah Williams |
| 3/21/2007 |
Exposure Tracking Model Ranking |
Initial ranking completed. |
Deborah Williams |
| 7/20/2007 |
Update or Other Action |
ADEC received and reviewed SLR's Former Nenana Truck Stop Monitoring Well Installation Work Plan dated July 2007. The plan inlcudes the installation of 4 soil borings from which samples will be collected and analyzed for BTEX, GRO, DRO and RRO. The soil borings will be completed as monitoring wells. Groundwater samples will be collected and analyzed for BTEX, GRO, DRO and RRO. DEC requested the addition of EDB analysis for groundwater samples., |
Tamara Cardona-Marek |
| 12/14/2007 |
Update or Other Action |
ADEC received the 2007 Former Nenana Truck Stop Monitoring Well Installation and Groundwater Monitoring Report. Report indicates groundwater samples continue to have DRO, GRO, and RRO above cleanup levels. One sample contained benzene above clenup levels. Groundwater gradient information was collected in August 2007 and revealed a flow to the North. SLR suspects groundwater gradient may change significantly during the year. Soil samples collected from stockpile reveled only one sample with DRO above cleanup levels. |
Tamara Cardona-Marek |
| 4/11/2008 |
Update or Other Action |
Received the Former Nenana Truck Stop Temporary Well Point Installation and Ground Water Monitoring Work Plan. ADEC requests that some temporary wells are moved from the far northeast end of property to north of area of concern. ADEC also requests that at least an additional two temporary well samples are analyzed fro DRO, GRO and RRO. |
Tamara Cardona-Marek |
| 4/22/2009 |
Exposure Tracking Model Ranking |
Initial ranking with ETM completed for source area id: 78768 name: Area Northeast of tanks |
Tamara Cardona-Marek |
| 5/11/2009 |
Document, Report, or Work plan Review - other |
ADEC received the Former Nenana Truck Stop 2008 Site Investigation and Groundwater Monitoring report. According to the report, SLR installed 17 well points and collected 4 soil cores in June 2008; and installed 6 groundwater monitoring wells and an additional 12 soil cores in October 2008. SLR also sampled all existing groundwater monitoring wells during the June 2008 sampling event. Results from the investigations revealed a release source near well point WP-11. Contamination with benzene, toluene, ethylbenzene, gasoline range organics (GRO), diesel range organics (DRO), and residual range organics (RRO) above cleanup levels was found in groundwater at WP-11 as well as in nearby soil borings B-13, B-14, B-16, B-17, and B-22. Contamination above cleanup levels was also found in groundwater near the dispenser island location and in nearby soil borings B-2, B-7, B-19, and B-11. DEC provided recommendations that included silica gel cleanup for RRO analysis, identification of the source near WP-11, a cleanup plan, and an updated conceptual site model. |
Tamara Cardona-Marek |
| 6/25/2009 |
Document, Report, or Work plan Review - other |
ADEC received the Former Nenana Truck Stop 2009 Groundwater Monitoring Work Plan submitted by SLR. |
Tamara Cardona-Marek |
| 6/26/2009 |
Site Characterization Workplan Approved |
2009 groundwater Monitoring Work plan has been approved. Work expected to begin week of June 29th. |
Tamara Cardona-Marek |
| 3/26/2010 |
Document, Report, or Work plan Review - other |
Received report in Feb 2010, and follow-up call from consultant; will discuss 2009 sampling results during mid-April. |
Jim Fish |
| 5/4/2010 |
Document, Report, or Work plan Review - other |
Reviewed and commented on 2009 Groundwater Monitoring Report; suggested collecting MNA geochemical parameters, additional soil contamination delineation near fue island dispenser, description of potential surface water interactions (and update to CSM), and performing building survey to assess vapor intrusion potential. |
Jim Fish |
| 5/28/2010 |
Update or Other Action |
Phone discussion with consultant addressing report review comments & pending workplan submittal for summer/fall data collection. |
Jim Fish |
| 7/7/2010 |
Document, Report, or Work plan Review - other |
Draft work plan for groundwater monitoring received from consultant (7/6/2010). Comments sent to consultant on 7/7/2010. |
Jim Fish |
| 7/14/2010 |
Site Characterization Workplan Approved |
Revised Workplan for groundwater monitoring approved 7/14/10; According to the workplan, consultants will:
Perform annual maintenance on frost jacked well casings and resurvey all existing monitoring wells at the Site; Monitor groundwater elevations at all existing groundwater monitoring wells on a monthly basis at the Site; Collect two rounds of groundwater samples from existing on-site wells for the purpose of measuring groundwater quality at the Site; and
Document site work and findings in a summary report. Findings will include an evaluation of groundwater assimilative capacity for benzene.
|
Jim Fish |
| 12/17/2010 |
Potentially Responsible Party/State Interest Letter |
PRP Letter sent to Crowley Maritime Corporation after discovery of PRP Letter lacking in site file. |
Jim Fish |
| 7/1/2011 |
Document, Report, or Work plan Review - other |
Received 2010 groundwater monitoring report from consultant. |
Jim Fish |
| 8/8/2011 |
Document, Report, or Work plan Review - other |
Reviewed and accepted 2010 Groundwater Monitoring Report -recommended cleanup plan be submitted for both groundwater (MNA) and soil (excavation) remedial actions, and sub-slab soil gas be collected for vapor intrusion evaluation. |
Jim Fish |
| 8/18/2011 |
Site Characterization Workplan Approved |
Work plan for groundwater sampling reviewed and approved. |
Jim Fish |
| 12/21/2011 |
Document, Report, or Work plan Review - other |
Received 2011 groundwater monitoring report |
Jim Fish |
| 5/29/2012 |
Document, Report, or Work plan Review - other |
2011 GW Monitoring Report approved; RRO & RRO with silica gel cleanup indicate that AK103 is not necessary in the future. |
Jim Fish |
| 7/3/2012 |
Meeting or Teleconference Held |
Met with RP (Crowley) and consultant (SLR) to discuss continued charcterization of groundwater, and soil and groundwater cleanup options. Cleanup plan and monitoring well replacement pending. |
Jim Fish |
| 8/9/2012 |
Site Characterization Workplan Approved |
Groundwater sampling, monitoring well installation, and monitroing well decommissioning work plan approved. |
Jim Fish |
| 10/5/2012 |
Document, Report, or Work plan Review - other |
Work plan for targeted soil excavation & stockpiling received. |
Jim Fish |
| 10/12/2012 |
Cleanup Plan Approved |
Soil excavation and temporary stockpile storage plan approved. Migration to groundwater cleanup levels are appropriate for this site, but may not be fully obtainable with this particular excavation near a building. Groundwater cleanup is also underway (as MNA), but may transition to enhanced bioremedaition. A Groundwater Cleanup Plan and Soil Management Plan was requested from consultant. |
Jim Fish |
| 10/19/2012 |
Update or Other Action |
Approval of liners & cover for temporary soil stockpile; sent consultant ADEC Landfarming Memorandum for landfarm work plan. |
Jim Fish |
| 2/11/2013 |
Update or Other Action |
Received 2012 Soil excavation and temproary stockpile report |
Jim Fish |
| 3/27/2013 |
Update or Other Action |
Received 2012 Groundwater Monitoring report |
Jim Fish |
| 5/3/2013 |
Document, Report, or Work plan Review - other |
Soil excavation and stockpiling report approved; work plan for addtional monitoring & remedial action requested. |
Jim Fish |
| 5/6/2013 |
Update or Other Action |
Received leter from consultant describing intent of fate and transport modeling to determine whether site conditions support the presence of a stable contaminant plume. EMD results (SRB and bssA) also included. |
Jim Fish |
| 6/25/2013 |
Offsite Soil or Groundwater Disposal Approved |
Approved soil transport to OIT for thermal remediation in lieu of land farming. |
Jim Fish |
| 7/9/2013 |
Update or Other Action |
Recieved Work Plan for soil transport & sulfate addition to trench. |
Jim Fish |
| 7/15/2013 |
Meeting or Teleconference Held |
Met with consultant to discuss use of Four-Phase calculator to modeling groundwater concentrations from silt-bound contamination and assess plume stability, as part of MNA evalaution. Final report, synthesis of proposed actions & work plan for additional sulfate addition forthcoming.
|
Jim Fish |
| 7/18/2013 |
Document, Report, or Work plan Review - other |
Received responses to DEC's comments/dsicussion on Four-phase calculator. Approved the 2012 Groundwater Monitoring Report with revisions, and approved the Work Plan for 2013 Fuel Island Soil Management and sulfate addition.
|
Jim Fish |
| 8/13/2013 |
Update or Other Action |
Received groundwater monitoring work plan. |
Jim Fish |
| 8/15/2013 |
Document, Report, or Work plan Review - other |
Groundwater monitoring workplan approved for Fall 2013. |
Jim Fish |
| 11/15/2013 |
Document, Report, or Work plan Review - other |
Reviewed and approved Fuel Island Soil Management (Transport & Thermal Remediation of 541.01 tons at OIT) and sulfate addition (950 lbs) report for 2013. |
Jim Fish |
| 1/15/2014 |
Document, Report, or Work plan Review - other |
Received 2013 Groundwater monitoring report |
Jim Fish |
| 4/11/2014 |
Site Characterization Report Approved |
Approved 2013 groudwater monitoring report |
Jim Fish |
| 5/15/2015 |
Document, Report, or Work plan Review - other |
Received 2015 groundwater monitoring work plan for review. |
Jim Fish |
| 5/19/2015 |
Document, Report, or Work plan Review - other |
Approved 2015 groundwater monitoring workplan; groundwater samples will be collected from the site monitoring wells and analyzed for BTEX, GRO, and DRO compounds, and water from select wells will be analyzed for geochemical parameters. In addition, a sample will be collected from monitoring well MW-18 for qPCR analysis and enumeration of bss and aps genes. Field work is to be conducted August 2015. |
Jim Fish |
| 2/3/2016 |
Update or Other Action |
Received 2015 Groundwater Monitoring Report February 1, 2016. |
Laura Jacobs |
| 4/5/2016 |
Update or Other Action |
Review comments of 2015 Groundwater Monitoring report sent to consultant for RP. |
Laura Jacobs |
| 7/29/2016 |
Update or Other Action |
DEC received a letter from the consultant for Crowley responding to our review of their 2015 Groundwater Monitoring Report. They have agreed to evaluate the vapor intrusion pathway at the Site, and based upon this fall's geochemistry results will decide whether to add nutrients to the groundwater to encourage biodegradation. |
Laura Jacobs |
| 8/8/2016 |
Update or Other Action |
Received a work plan for the 2016 Groundwater Monitoring from SLR Consulting, Inc. This year's work will include annual groundwater sampling, pilot study for addition of sulfate, a vapor intrusion building survey for the sandwich shop on site, and an update to the 2009 conceptual site model. Work is planned for early-mid September. |
Laura Jacobs |
| 12/14/2016 |
Update or Other Action |
Received "Former Nenana Truck Stop, 2016 Groundwater Monitoring Report, Nenana, Alaska, December 2016." |
Laura Jacobs |
| 1/23/2017 |
Document, Report, or Work plan Review - other |
DEC staff reviewed the "2016 Groundwater Monitoring Report, Nenana, Alaska, December 2016" prepared by SLR. Activities included well repairs, groundwater monitoring for natural attenuation parameters and contaminants of concern, a vapor intrusion building survey, an update of the 2009 Conceptual Site Model, and a pilot study for the addition of supplemental sulfate to the groundwater. In 2017, SLR will assess whether adding sulfate to specific wells in 2016 will have resulted in decreased levels of BTEX. DEC suggested SLR consider microbial assays to complement monitoring geochemistry and contaminants of concern. Results of the vapor intrusion building survey were similar to the survey taken in 2010. DEC recommends measuring sub-slab vapor concentrations because vapor intrusion has the potential to occur as discovered in the Conceptual Site Model. The general trend in contaminant levels in groundwater were to decline. SLR recommends continued monitoring at eleven monitoring wells, and dropping wells MW-14 and MW-15. DEC recommended SLR conduct trend analysis on the groundwater sample dataset to determine if the contaminant plume is stable or decreasing. |
Laura Jacobs |
| 3/15/2017 |
Document, Report, or Work plan Review - other |
DEC reviewed comments sent by Crowley's consultant in response to DEC's comment letter after reviewing the 2016 groundwater monitoring report. During the 2017 sample periods of spring and fall, SLR plans to conduct microbial assays at select wells, conduct vapor intrusion measurements of the building sub-slab, and will evaluate the historical groundwater monitoring data for trends for closure decisions. |
Laura Jacobs |
| 4/12/2017 |
Meeting or Teleconference Held |
DEC met with representatives from CPD Alaska, LLC and Weston Solutions, Inc. (their consultant)to discuss progress at sites in Nenana and Kotzebue. DEC will send review comments, historical information update for Nenana terminal, and make recommendations for work at the Kotzebue sites. |
Laura Jacobs |
| 4/20/2017 |
Update or Other Action |
Received work plan from SLR for 2017 season. Monitoring wells will be inspected, repaired if needed and then groundwater level measurements will be collected. Groundwater samples will be taken from all available wells. Sub-slab soil gas probes will be installed to collect soil gas samples in three locations. Water quality data will be collected to assess the effectiveness and distribution of the 2016 application of sulfate. |
Laura Jacobs |
| 4/26/2017 |
Document, Report, or Work plan Review - other |
DEC reviewed the 2017 work plan for the site and sent approval through an email (in e-file). |
Laura Jacobs |
| 5/30/2017 |
Update or Other Action |
Crowley staff P. Kodial called to discuss outstanding items Crowley needs before they can proceed with site progress. DEC will provide review comments from a 2012 report for Kotzebue Airport sites and Crowley will provide work plans for all sites. |
Laura Jacobs |
| 2/9/2018 |
Document, Report, or Work plan Review - other |
ADEC staff completed a review of the report "2017 Groundwater Monitoring and Sub-Slab Soil Gas Sampling Report, Nenana, Alaska, December 2017". Two groundwater monitoring events (July and September 2017), sub-slab vapor intrusion sampling, and a pilot study for addition of supplemental sulfate to increase natural attenuation of remaining petroleum compounds were accomplished. Results from groundwater monitoring indicate the plume is shrinking, but advised conducting statistical trend analysis to be sure. Vapor intrusion does not appear to be a concern based upon results from the sub-slab gas samples. Sulfate injection appears to be making a difference but ADEC requested results to be presented graphically. |
Laura Jacobs |
| 2/15/2018 |
Update or Other Action |
ADEC staff received a response to review comments sent regarding the 2017 groundwater monitoring report. RP's contractor is in agreement with trend analysis to determine plume changes, and removing sub-slab gas probes from inside the Truck Stop building. |
Laura Jacobs |
| 7/18/2018 |
Meeting or Teleconference Held |
ADEC staff met with the current owner of the Nenana Truck Stop, SLR and Crowley staff to discuss closure plan and make recommendations. |
Laura Jacobs |
| 7/20/2018 |
Document, Report, or Work plan Review - other |
ADEC staff drafted a letter with review comments for the "Site Assessment and Closure Plan, Former Nenana Truck Stop" received by the ADEC office June 5, 2018 and discussed at the July 18 meeting with ADEC staff, SLR and Crowley staff and the current property owner. Comments included a request for an investigation of remaining petroleum contamination beneath the lined area of the above ground tanks and in the area of the discovered drum dump; additional groundwater monitoring to establish trends of stable and decreasing contamination; an inventory of remaining monitoring wells and a plan to decommission wells that aren't being sampled; and, establish an alternative point of compliance prior to closure. |
Laura Jacobs |
| 8/14/2018 |
Update or Other Action |
ADEC staff received written responses to ADEC comments regarding SLR's "Draft Site Assessment and Closure Plan". Crowley agreed to evaluate the need for additional investigations into remaining contaminated soils in the area of the former Underground Storage Tanks and the fuel island. Groundwater monitoring will continue to be conducted until contaminant levels are clearly stable or decreasing. Crowley also agreed to conduct a second sub-slab soil gas sample event, sometime during the winter of 2018-2019 before removing the soil gas probes. |
Laura Jacobs |
| 9/11/2018 |
Document, Report, or Work plan Review - other |
ADEC staff reviewed the work plan "2018 Groundwater Monitoring and Sub-Slab Soil Gas Sampling Work Plan Former Nenana Truck Stop" and provided comments to SLR. The work plan was approved with the acknowledgement that further characterization activities around the above ground fuel storage tank farm area would occur in the future. |
Laura Jacobs |
| 5/23/2019 |
Document, Report, or Work plan Review - other |
ADEC staff reviewed the "Former Nenana Truck Stop, 2018 Groundwater Monitoring and Sub-Slab Soil Gas Sampling Report, Nenana, Alaska". SLR proposes to decommission the sub-slab soil gas probes after there weren't hydrocarbons detected above target levels during the summer and winter sample events. They would also like to decommission monitoring wells MW-4, MW-14, MW-15 as sample results have consistently not had contaminants detected in sample results. ADEC has agreed to these recommendations. SLR has satisfactorily demonstrated that DRO detections in MW-8 are due to naturally occurring organic material and are not from petroleum hydrocarbons. Sample results, in general, have remained above cleanup levels for wells MW-1, MW-5, MW-8, MW-11,and MW-19. |
Laura Jacobs |
| 8/30/2019 |
Document, Report, or Work plan Review - other |
ADEC staff reviewed the 2019 Groundwater Monitoring and Well Decommissioning Work Plan for the Former Nenana Truck Stop. Comments were sent suggesting some additional work. Plans include decommissioning four wells and replace MW-1 with MW-1R, advance additional borings adjacent to the former fuel island excavation, inspect all wells and repair as needed, collect groundwater samples, and abandon three sub-slab soil gas probes. |
Laura Jacobs |
| 9/11/2019 |
Document, Report, or Work plan Review - other |
The work plan is amended to include two additional soil borings in the NE containment area, and one surface sample outside of containment area. |
Laura Jacobs |
| 5/26/2020 |
Document, Report, or Work plan Review - other |
ADEC issued comments for the 2019 Groundwater Monitoring and Supplemental Soil Investigation Report. Soil contamination in the Former Fuel Island source area continues to have contamination in excess of Human Health cleanup levels. Preliminary sample results also indicate there is a uncharacterized plume in the northeast corner of the AST Containment Area. |
Laura Jacobs |
| 8/14/2020 |
Document, Report, or Work plan Review - other |
Work plan for additional site investigations was approved by ADEC staff. The RP plans to extend sampling to the northeastern area of the site near the above ground storage tank pad, where contaminants have continued to exceed migration to groundwater cleanup levels. Soil pits, borings, additional groundwater monitoring wells, as well as sampling existing groundwater monitoring wells will take place this fall. |
Laura Jacobs |
| 2/18/2021 |
Document, Report, or Work plan Review - other |
ADEC reviewed the annual monitoring report, "2020 Groundwater Monitoring and supplemental Soil Investigation Report" submitted on January 12, 2021, from SLR. Groundwater contamination was found in three source areas that were documented in past efforts. Preliminary efforts were conducted to understand where contamination was located in the NE containment area, and whether it was above the liner or below. |
Laura Jacobs |
| 6/16/2021 |
Meeting or Teleconference Held |
A Teams meeting was held with Crowley Fuels, and SLR Consulting, Inc., to discuss a proposed different approach to remediation and further site characterization of the NE source area that originated near the Above Ground Storage Tank lined facility. A Work Plan will be sent after agreement at this meeting has occurred. |
Laura Jacobs |
| 6/17/2021 |
Meeting or Teleconference Held |
ADEC staff met with Crowley and SLR staff electronically to discuss potential strategies for remediation on site in addition to the annual monitoring. Strategies that were proposed include clearing the northern part of the site, tilling in sulfate to surface soils in fall and injecting sulfate into strategic wells. One additional monitoring well will be installed to understand the plume edge in the area to the north of the lined tank facility. |
Laura Jacobs |
| 7/13/2021 |
Document, Report, or Work plan Review - other |
ADEC reviewed and commented on the Remediation Work Plan Former Nenana Truck Stop Nenana, Alaska received by our office July 9, 2021. The work plan proposes remediation and further site characterization. Specifically, a monitoring well will be newly installed downgradient of the known extent of the plume north of the former above ground storage tank containment liner and in the vicinity of the suspected drum burial area on Lot 2. Monitoring of groundwater quality will continue in existing and newly installed wells. This year, areas in source areas will be cleared for a surface application of sulfate. Sulfate injections will also continue in select monitoring wells after sample collection has occurred. There will be follow-up sample collection to document the effectiveness of monitored natural attenuation. |
Laura Jacobs |
| 9/23/2021 |
Site Visit |
ADEC staff made a site visit during the three day period when the RP's consultant was going to be preparing the site, sampling groundwater wells, and applying and injecting sulfate amendments. |
Laura Jacobs |
| 1/28/2022 |
Document, Report, or Work plan Review - other |
The 2021 Remediation Report was received by the DEC office December 6, 2022. A review of remedial and characterization work was completed. Groundwater was monitored at existing wells and one newly installed well downgradient of the known extent of hydrocarbon plume to assess impacts beneath the former above-ground storage tank containment liner. Three source areas were cleared of vegetation and sulfate was land applied as well as injected into select wells. Monitored Natural Attenuation was evaluated. |
Laura Jacobs |
| 6/22/2023 |
Document, Report, or Work plan Review - other |
A work plan for the 2023 Groundwater Monitoring event at the Former Nenana Truck Stop was reviewed and an approval with comments were sent. Proposed efforts include gauging water levels and collecting groundwater samples from existing monitoring wells. A sulfate solution will be injected into wells MW-1R, MW-19, MW-9, MW-20, and MW-11, and then sampled for microbial gene analysis to determine quality of anaerobic and aerobic biodegradation of petroleum hydrocarbons. |
Laura Jacobs |
| 2/9/2024 |
Document, Report, or Work plan Review - other |
DEC staff reviewed the annual monitoring report "2023 Performance Monitoring Report, Former Nenana Truck Stop, Nenana, Alaska" received December 14, 2023. The qualified environmental professional, SLR International, determined the groundwater flow direction was to the north-northeast. Groundwater samples from six monitoring wells were analyzed for petroleum hydrocarbons. Three of the six wells had benzene and ethylbenzene that exceeded the DEC Table C. Groundwater cleanup levels. Diesel range organics (DRO) were above the groundwater cleanup level in two wells. It was suggested that the continued elevated DRO levels in MW-8 are due to biogenic interference. Magnesium sulfate was spread over the three source areas in 2021 which resulted in sulfate percolating through the contaminant mass and into groundwater. Results indicated microbial concentrations in groundwater increased from 2021 to 2023, along with the magnesium and sulfate. Enzymes associated with microbial anaerobic biodegradation also increased. |
Laura Jacobs |
