| Action Date |
Action |
Description |
DEC Staff |
| 12/31/1964 |
Update or Other Action |
The Eklutna Army Site was used by the United States Army as a supply and storage area from 1957 to 1971. The Eklutna Army Site consisted of 48 Quonset huts, 2 Bureau of Indian Affairs buildings, 2 distinct storage lots, a helicopter landing pad, and numerous small support structures. As part of a historic archive search USACE-AK obtained a 1964 aerial photograph of the site (Figure 4). A detailed review of the aerial photograph revealed the following site features that may have resulted in a release of contaminants to the environment:
• 50 above ground storage tanks (ASTs)
• 5 drum piles
• 2 transformers
• 2 dump sites
• 2 potential underground storage tank (UST) locations
A power generation facility was not identified on the 1964 aerial photograph. It appears that
electricity was supplied from Fort Richardson via power lines along the rail road tracks. Most of
the structures were not supplied with running water. Multiple “outhouse” style latrines were
identified on the aerial photograph and during prior site visits. With exception to the 1964 aerial photograph, the archive search revealed no additional information that could be used to identify potential sources of contamination or release mechanisms. |
Debra Caillouet |
| 9/30/2005 |
Update or Other Action |
The Native Village of Eklutna (NVE) has had multiple Cooperative Agreements (CAs) under NALEMP. Since fall of 2005, NVE has hauled over 860,000 lbs. of military debris to the Anchorage landfill and metal recyclers. This included building rubble, remains of Quonset hut frames and other structural debris, thousands of feet of 16 strand barbed wire fencing, barrels, metal track “marsh mats”, over 10,000 lbs. of “mineral wool” layered with wire mesh, and a range of other debris.
NVE has filled in entrapment hazards, such as old latrine pits, and leveled berms, some as large as 1,000 feet long by 50 feet tall. Debris was also removed from the military landfill to a depth of around 4 feet. (*See Eklutna NALEMP Drum Removal CS DB HazID 4310 File# 2108.38.003 reckey# 200621X926901). |
Debra Caillouet |
| 9/29/2006 |
Update or Other Action |
In 2006, NVE removed 55 buried drums from the Drum Dump Area that contained paint, solvent
and tar (Figure 2). In 2009, another 62 drums of similar contents were removed from the site and
three soil samples were collected to characterize the contaminated soil that surrounded the
drums. Samples were analyzed for metals and volatile organic compounds (VOCs). The
disturbed area featured chunks of dried paint and tar and the location of a former leaking drum
presented a volatile odor. A sample collected from the spill area identified elevated lead and
benzene. (*See Eklutna NALEMP Drum Removal CS DB HazID 4310 File# 2108.38.003 reckey# 200621X926901). |
Debra Caillouet |
| 6/25/2008 |
Update or Other Action |
On or about June 25, 2008, during normal gravel extraction operations within the current gravel
pit, personnel from Alaska Aggregate Products (AAP), a subsidiary of AIC, uncovered a pocket
of material which exhibited a noticeable “volatile” petroleum, oil, and/or lubricant (POL) odor.
Mr. Russell Vogel of AAP contacted Environmental Management, Inc. (EMI) to investigate the
size and type of contamination. EMI performed soil screening and sampling on behalf of AAP
on June 26, 2008.
Photo Ionization Detector (PID) headspace readings were gathered from 5 different locations within an approximately 15-foot by 15-foot area where contamination seemed most prevalent. The highest PID readings ranged near 500 parts per million (ppm). The soil sample with the highest PID reading was sent for laboratory analysis of gasoline-range organics (GRO), diesel-range organics (DRO), residual-range organics (RRO), volatile organic compounds (VOCs), semi-volatile organics (SVOCs), pesticides, polychlorinated biphenyls (PCBs), pH, and metals (arsenic, barium, cadmium, chromium, lead, selenium, silver, and mercury).
Notable results were 1,680 milligrams per kilogram (mg/kg) DRO and 15.4 mg/kg GRO. Based on these results, AAP suspended gravel extraction operations in this area. |
Debra Caillouet |
| 7/25/2008 |
Update or Other Action |
Complaint/Report Received. Young Ha. Spill report received via phone. Completed spill reporting form received electronically from Todd Maw with AAG. Cleanup plan requested by Young Ha - sent email requesting for a cleanup plan. |
Debra Caillouet |
| 7/29/2008 |
Update or Other Action |
Young Ha. Received soil sampling report. This report describes work sample activities that were conducted to delineate the contaminated area.
EMI performed the screening and soil sampling on June 26, 2008. Upon arrival at the site, EMI
personnel used PID equipment and hand tools to delineate an approximately 15' x 15' (225 sq. ft.) area where the contamination seemed most prevalent. headspace samples were analyzed from 5 (nine are required) different locations around the contaminated area (north quadrant, south quadrant, east quadrant, west quadrant, and center.)
Of the 5 in-situ locations field screened via PID, the highest result was from the center location; soil from this location was collected (two are required in addition to any QA/QC samples) into laboratory-provided containers, and transported to the lab along with a chain of custody.
PID headspace readings from this area ranged from several ppm to almost 500 ppm. A lab sample was collected from the center of this area (the location showing the highest PIO reading), and submitted to SGS labs in Anchorage for a variety of analyses.
NOTE: 2010 May Draft Field Sampling Guidance states: 1 field sample per 25 sq. ft. = 9 field screening samples. 2 laboratory samples (independent of any required QA/QC samples) are required for areas 125 to 250 sq. ft. in size.
EMI recommends the removal, proper treatment and disposal of this material in order to achieve a
clean closure for this spill site with no further action required. |
Debra Caillouet |
| 7/30/2008 |
Update or Other Action |
Initial WP received by Young Ha.
The primary purpose of this action is to remove all contaminated soils found at the contaminated site. The contaminated soils will be placed in a lined cell for storage. We expect the excavation to only be required to go down a few feet. If the contamination is still present four feet down, ADEC will be notified. However, the plan will be to continue excavating until all contaminated soils are removed.
Cleanup Level: Method two from 18 AAC 75 was used to determine the cleanup levels for this project. For this project the soil will be considered clean if concentrations are Less than the threshold levels listed in Table Bl&B2, 18 AAC 75.340 in the "Under 40 inch zone", and "Migration to Groundwater" column of the control document. Specific identified compounds of concern are diesel range organic (DRO) compounds which have a clean up level of 250 mg/kg.
Schedule: These excavation activities are planned to be conducted Friday, August 1, 2008.
The soil samples will be analyzed for the following compounds: DRO by AK Method 102. NOTE: May 2010 Draft Field Sampling Guidance requires for releases from diesel #1 or arctic diesel, #2 diesel: GRO, DRO, BTEX, PAHs.
Confirmation Sampling- excavation of suspect area: Field screening of the soils left after the
excavation will be conducted with a PID to determine sample locations for laboratory analysis
of the insitu soils. The field screening frequency of the insitu soils will be one every 100
sq.ft. (basically one every 10 linear feet).
The laboratory samples will be collected from the locations with the highest PID results. The laboratory sampling frequency for the in-situ soils, once excavation is complete, will be a minimum of two samples from each area, one from the sides and one from the floor with one additional sample for each additional 250 square feet of excavation area above an initial 250 square feet.
NOTE: Draft May 2010 Field Sampling Guidance states for more than 250 sq. ft. surface area: 10 field screening samples PLUS 1 per additional 100 sq. ft. or as the ADEC determines necessary.
Characterization Sampling - stockpiled soils: The stockpile will be screened by collecting a
heads pace sample every 10 CY. If the stockpiled soil data are consistent with the previously
collected data no laboratory samples will be collected. If significantly different soils are
encountered, two laboratory samples will be collected to characterize the pile. The samples
will be collected from the two locations with the highest PID results. |
Debra Caillouet |
| 8/18/2008 |
Document, Report, or Work plan Review - other |
Phase II Site Remediation Work Plan for Eklutna Army Site, August 2008
Waste handling and disposal. The regulations at 18 AAC 75.325(i) require DEC approval
before shipping waste off-site. Please provide the information on the proposed waste
disposal to DEC for approval prior to off-site shipment.
DEC provides cleanup levels for various hazardous substances in our regulation at 18 AAC
75.341 for soil and 75.345 for groundwater. These cleanup levels are based on the pathways
by which receptors could be exposed to the contaminants. These are risk based cleanup
levels. DEC does not provide health standards.
See site file for additional information. |
Debra Caillouet |
| 7/2/2009 |
Update or Other Action |
Young Ha. Email requesting status of the case sent to Larry Helgeson with EMI. |
Debra Caillouet |
| 7/22/2009 |
Meeting or Teleconference Held |
Young Ha. Received a call from Larry Helgeson with EMI. Work to explore the extent of the contamination was never conducted last year. Due to flooding in the area, all the site markers were washed away. They are unable to relocated the site. A work plan will be submitted to propose method they will use to relocated the site |
Debra Caillouet |
| 9/4/2009 |
Document, Report, or Work plan Review - other |
The Alaska Department of Environmental Conservation (DEC) received the above referenced
work plan via e-mail on September I , 2009. The work plan contains the minimum
requirements for a site characterization plan and does not propose to determine if any
contamination has migrated further than six inches below the bottom of the excavation. This
may not be adequate to characterize the extent of any contamination at the site. If there are
contaminants detected in the proposed samples, additional sampling and analysis will be
required.
The plan also does not contain any provision for back filling the excavation. If the excavation
will be left open, a safety professional should be consulted to determine the best way to
mitigate any risk from the excavation.
DEC has no objection to the implementation of the plan. While DEC may provide comment on
regulations other than 18 AAC 75, this does not relieve the Native Village of Eklutna from
compliance with all applicable state and federal regulations applicable to the work. Please
provide the results as soon as practicable. |
Debra Caillouet |
| 9/30/2009 |
Update or Other Action |
In 2009, NVE removed 90 tons of contaminated soil but funds were insufficient to complete the
contaminated soil excavation at that time. Five soil samples were collected from areas that
presented the highest photo-ionization detector (PID) readings. Three soil samples were
collected to characterize the portion of excavation considered complete based on screening. Two
samples were collected from the area of known contaminated soil that remained. Results from the samples collected from areas suspected to be clean were below clean-up levels for the target
analytes. Results from soil samples collected from the soil remaining to be excavated featured
exceedences of clean-up levels for 1,2,4 Trimethylbenzene and lead. Significant amounts of dried potentially lead based paint were visible in the excavation. (*See Eklutna NALEMP Drum Removal CS DB HazID 4310 File# 2108.38.003 Reckey# 200621X926901). |
Debra Caillouet |
| 9/30/2009 |
Update or Other Action |
Between August and September, 2009, AIC contracted TERRASAT, Inc. (TERRASAT) to evaluate baseline ground water conditions as part of the permitting process for the expansion of the gravel pit. TERRASAT installed four groundwater monitoring wells around the perimeter of the future gravel extraction area (Figure 2).
Groundwater sample results from two of the wells (MW-3 and MW-4) contained DRO concentrations of 0.14 milligrams per liter (mg/L) and 0.47 mg/L, respectively. |
Debra Caillouet |
| 10/9/2009 |
Update or Other Action |
Evaluation of Groundwater Quality Aug-Sept 2009 (TERRASAT) received.
TERRASAT, Inc (TERRASAT) compared results from the August-September, 2009 sampling of five monitoring wells and one public water supply well to Alaska Quality Standards listed in 18 AAC 80 and 18 AAC 75. Refer to Table 1 for analytical results and Alaska Water Quality Standards.
Results for Gasoline Range Organics (GRO) and Benzene, Ethylbenzene, Toluene, and total Xylenes (BTEX) are below detection limits for all wells tested during this sampling effort.
Analytes that exceed the 1B AAC 80, Fe, Al, and Mn, are likely at natural levels in the aquifer system. Glacial-fluvial deposits, which make up the strata of the Anchorage bowl area, often have high concentrations of these analytes. The likely source of the diesel range organics found in MW-3 and MW-4 is from a previous military installation in the area, referred to as Camp Mohawk. MW-4
and MW-3 are northeast of a previous military vehicle parking area and are directly on a previous helicopter landing strip. Figure 2 shows the Camp Mohawk facilities in relation to the current monitoring well locations.
Diesel range organic hydrocarbons are typically not very mobile in aquifers. Studies in California of more than 200 plumes of fuel releases showed that less than 2% of the plumes reached 1,000 feet in length. Since gasoline range organics and other volatile organic compounds are below laboratory detection levels, TERRASAT concludes that the diesel range organic hydrocarbons are weathered and relatively old. TERRASAT concludes that the source of diesel
range contamination is likely within 200 feet of monitoring wells MW-3 and MW-4. TERRASAT cautions that a public water supply well is approximately 1,000 feet east of monitoring wells MW-3 and MW-4.
The water quality of the deeper local drinking water aquifer is different than the upper unconfined aquifer. This is shown by the relative concentration of some analytes between the two aquifers. The deeper aquifer is higher in zinc, arsenic, and pH and is lower in mercury, nickel, and aluminum than the shallow water table aquifer.
The water table aquifer is separated from the deeper, confined aquifer by approximately 123 feet of impermeable silt and clay. The deeper local drinking water aquifer showed static water at 29 feet below the ground surface. During drilling, water was encountered at approximately 158 feet below the ground surface, meaning that the ground water moves upward approximately 129 feet
from the deeper aquifer.
Because of these findings TERRASAT believes that there is no interaction between the upper aquifer and the deeper local drinking water aquifer. Therefore, the drinking water is safe and will remain safe from past, present, and future activity in the area.
TERRSAT recommends quarterly detection monitoring of these five monitoring wells with the reduced suite of analytes of: Phosphorous, Chloride, Zinc, conductivity, and pH. Due to the presence of DRO in MW-3 and MW-4, we recommend that these wells continue to be monitored for DRO. We also
recommend that MW-2, the cross gradient and closest monitoring well to the Eklutna Gate Well, be monitored for DRO. Additional sampling is needed for higher confidence in statistical results, as well as a better understanding of seasonal trends in ground water analyte concentrations.
TERRASAT recommends notifying the ADEC regarding the detection of diesel range organics in the ground water at MW-3 and MW-4.
We further recommend developing a release investigation strategy to identify the source of contamination so that the source can be mitigated. ADEC should be allowed to review and approve the release investigation plan before the plan is implemented. |
Debra Caillouet |
| 5/7/2010 |
Update or Other Action |
Young Ha. Request for final report sent via email to Todd Maw. |
Debra Caillouet |
| 5/12/2010 |
Update or Other Action |
Spill Summary Report # 08239917602 Young Ha. Final report received.
During groundwater monitoring at the site in May 2010, contamination was discovered. This case is being picked up by CS as a FUDS site. Contaminated soil was discovered during excavation of the area for aggregate. Characterization sample was collected by EMI. The contaminant of concern was determined to be ORO. The site is an old military site. Transferred to CS Program Deb Caillouet. |
Debra Caillouet |
| 6/3/2010 |
Update or Other Action |
USACE-AK conducted a site visit on June 3, 2010 to determine if the reported DRO contaminated
soil was a result of activities at the Eklutna Army Sites FUDS. USACE-AK visually inspected the area of contaminated soil and met with AAP, TERRASAT, Eklutna Inc., and Native Village of Eklutna personnel. |
Debra Caillouet |
| 9/30/2010 |
Update or Other Action |
In 2010, NVE excavated another 116 tons of soil as detailed in the 2010 Site Activity Report.
Excavation reached a maximum depth of 13 feet below ground surface (bgs) where screening results indicated significant contamination had not extended past that point. Sampling at the extent of final excavation included 6 samples analyzed for residual range organics (RRO), diesel range organics (DRO), gasoline range organics (GRO), VOCs, semi-volatile organic compounds (SVOCs), and metals. Two samples exceeded the Alaska Department of Environmental Conservation (ADEC) Method 2 Migration to Groundwater Cleanup Level (0.031 milligrams per kilogram [mg/kg] and 0.059 mg/kg) for Trichloroethylene (TCE). All remaining analytes were significantly below soil clean-up levels.
In response to the 2010 Site Activity Report, the ADEC requested additional characterization of
TCE at the Drum Dump Area. The NVE prepared a draft work plan in August 2012 under a new NALEMP Cooperative Agreement. The work plan is still in the draft stage with field work scheduled for the 2013 field season. This work plan assumes that any additional characterization of the Drum Dump Area will be completed by the NVE under the NALEMP CA. Additional contaminated soil removal will be performed by the FUDS program. (*See Eklutna NALEMP Drum Removal CS DB HazID 4310 File# 2108.38.003 Reckey# 200621X926901). |
Debra Caillouet |
| 1/31/2011 |
Update or Other Action |
Results of the June 3, 2010 site visit lead USACE-AK to complete a revised January 2011 Inventory Project Report (INPR) which authorized a Hazardous, Toxic, and Radioactive Waste (HTRW) project for the site. |
Debra Caillouet |
| 3/10/2011 |
Spill Transferred from Prevention Preparedness and Response Program |
Spill transferred by PERP staff Young Ha. Spill no. 08239917602; spill date = 6/24/08; substance = diesel; quantity = unknown. |
Mitzi Read |
| 4/12/2011 |
Document, Report, or Work plan Review - other |
UVOST Site Investigation Work Plan, Eklutna Army Sites, April 2011.
POL contamination is impacting the current gravel mining operations. The 2011 UVOST SI is
intended to be limited in scope and will focus on characterizing the cleared future gravel
extraction location. A Preliminary Assessment (PA) will be completed during 2012 to identify
all potential areas of concern. Results from the 2011 UVOST SI and the PA will be used to
develop a Work Plan for a Remedial Investigation (RI). A full RI is tentatively scheduled for
fiscal year (FY) 2013.
The objectives of the 2011 UVOST SI are summarized below:
• Identify the vertical and horizontal extent of POL-impacted surface and subsurface soil
contamination at the cleared future gravel extraction location using the UVOST
• Verify the contaminants of concern (COCs) impacting soil through sampling and
laboratory analysis
• Develop a correlation between petroleum contaminants and UVOST results
|
Debra Caillouet |
| 4/14/2011 |
Site Added to Database |
A new site has been added to the database |
Mitzi Read |
| 5/9/2011 |
CERCLA SI |
UVOST Site Investigation Work Plan, Eklutna Army Sites, Final April 2011.
The 2011 UVOST SI is intended to be limited in scope and will focus on characterizing the cleared future gravel extraction location. A Preliminary Assessment (PA) will be completed during 2012 to identify all potential areas of concern. Results from the 2011 UVOST SI and the PA will be used to
develop a Work Plan for a Remedial Investigation (RI). A full RI is tentatively scheduled for
fiscal year (FY) 2013.
The objectives of the 2011 UVOST SI are summarized below:
• Identify the vertical and horizontal extent of POL-impacted surface and subsurface soil contamination at the cleared future gravel extraction location using the UVOST
• Verify the contaminants of concern (COCs) impacting soil through sampling and laboratory analysis
• Develop a correlation between petroleum contaminants and UVOST results
The objectives of the site characterization sampling are to identify COCs that are impacting the
soil and to determine if the COCs are present at concentrations in excess of default ADEC
cleanup levels. Four site characterization soil samples (in addition to the 12 correlation samples) will be collected after completion of the UVOST investigation. If only a single fuel type is identified during the UVOST investigation the site characterization samples will be collected from the 4 locations that displayed the highest fluorescence. If multiple fuel types (gasoline, diesel fuel, motor oil, etc) are identified at least one site characterization sample will be collected from the soil displaying the highest fluorescence for each fuel type.
The sample analyses will include GRO, DRO, RRO, benzene, toluene, ethylbenzene, and xylene (BTEX),
PAHs, PCBs, and metals. The site characterization soil samples will be obtained with the Geoprobe Macrocore sampling system. Detailed sampling procedures are provided in the SAP. Sample holes will be immediately sealed with dry bentonite granules and marked with a labeled pin flag. |
Debra Caillouet |
| 5/31/2011 |
Update or Other Action |
USACE-AK attempted to perform a UVOST SI in May 2011. The UVOST investigation was
not completed. Site geology resulted in an elevated UVOST detection limit and substantial
damage to the UVOST tooling. Eight UVOST probes were completed at the site. All eight
probes were terminated due to refusal prior to reaching the water table.
The surface soil at one of the probe locations had a fuel odor. All probes displayed only background fluorescence. Two analytical samples were collected from the surface soil with a fuel odor and analyzed for GRO, DRO, RRO, VOCs, and SVOCs. DRO was the only detected analyte at 50 and 80 mg/kg. |
Debra Caillouet |
| 6/15/2011 |
Update or Other Action |
SI work plan received for review and comment.
2011 Site Investigation Objectives
POL contamination is impacting the current gravel mining operations. The 2011 SI is intended to be limited in scope and will focus on characterizing the cleared future gravel extraction location. A Preliminary Assessment (PA) will be completed during 2012 to identify all potential
areas of concern. Results from the 2011 SI and the PA will be used to develop a Work Plan for a
Remedial Investigation (RI). A full RI is tentatively scheduled for fiscal year (FY) 2013.
The objectives of the 2011 SI are summarized below:
• Identify the horizontal extent of POL-impacted surface and subsurface soil contamination at the cleared future gravel extraction location up to 18 feet below ground surface (bgs).
• Develop a correlation between petroleum contaminants and headspace field screening results.
The 2011 SI will
include approximately 30 test pits positioned within the cleared future gravel pit. The test pits
will be excavated in three phases and samples will be analyzed on an expedited schedule. The
phased approach will allow for the evaluation of the analytical results and identification of future
test pit locations. The approximate locations of the planned test pits are identified in Figure 4.
The actual test pit locations will be adjusted based on analytical data trends and the investigation objectives. Depth to groundwater is anticipated to be 35 feet bgs. It is anticipated that test pit depth will be 18 feet below ground surface due to the limits of the excavation equipment and site geology (i.e., sloughing soil).
The test pits will be excavated with a Caterpillar 320 excavator equipped with a 1.5 cubic yard
bucket, or equivalent. The excavator operator will attempt to remove a two foot lift of soil with
each excavator bucket. The project chemist will collect the samples from the center of the
excavator bucket in an attempt to collect soil that is representative of the target depth. The depth of each sample will be estimated based on the reach of the excavator. Gradations will be marked on the side of the excavator arm to aid in depth estimation. One headspace field screening
sample and collocated analytical sample will be collected to represent each two foot lift of soil.
It is anticipated that 9 soil samples will be collected from each test pit (0-2 feet bgs, 2-4 feet bgs, etc.) The analytical samples will be analyzed for DRO |
Debra Caillouet |
| 7/18/2011 |
Update or Other Action |
Draft WP Site Investigation received for review and comment.
The objectives of the 2011 SI will be achieved through the excavation of test pits, collection of
headspace field screening samples, and collection of analytical samples. The 2011 SI will include approximately 30 test pits positioned within the cleared future gravel pit. The test pits will be excavated in three phases and samples will be analyzed on an expedited schedule.
The phased approach will allow for the evaluation of the analytical results and identification of future test pit locations. The approximate locations of the planned test pits are identified in Figure 4. The actual test pit locations will be adjusted based on analytical data trends and the investigation objectives. Depth to groundwater is anticipated to be 35 feet bgs. It is anticipated that test pit depth will be 18 feet below ground surface due to the limits of the excavation equipment and site geology (i.e., sloughing soil).
The test pits will be excavated with a Caterpillar 320 excavator equipped with a 1.5 cubic yard
bucket, or equivalent. The excavator operator will attempt to remove a two foot lift of soil with
each excavator bucket. The project chemist will collect the samples from the center of the
excavator bucket in an attempt to collect soil that is representative of the target depth. The depth of each sample will be estimated based on the reach of the excavator. Gradations will be marked on the side of the excavator arm to aid in depth estimation. One headspace field screening
sample and collocated analytical sample will be collected to represent each two foot lift of soil.
It is anticipated that 9 soil samples will be collected from each test pit (0-2 feet bgs, 2-4 feet bgs, etc.) The analytical samples will be analyzed for DRO.
Soil that is suspected of being grossly contaminated, has an odor other than that of a weathered
fuel, is severely stained, and/or has visible product will be placed directly onto a 10 millimeter polyethylene liner. The sample from this highly contaminated soil will be analyzed for GRO, RRO, VOCs, polycyclic aromatic hydrocarbons (PAHs), and metals (arsenic, barium, cadmium,
chromium, lead, nickel, and vanadium) in addition to DRO. The additional analysis will be
performed only once per test pit and at a maximum of three test pit locations.
All excavated soil will be systematically stacked on the side of the excavation. After completion of the test pit and to the extent possible the excavated soil will be returned to its original location. No compaction of the excavated soil will be performed. The surface of the backfilled test pit will be graded to match the surrounding ground surface. |
Debra Caillouet |
| 7/28/2011 |
Document, Report, or Work plan Review - other |
Site Investigation Work Plan, Eklutna Army Sites, Draft June 2011
The work plan proposes investigation using test pits to characterize an area proposed for future gravel extraction. ADEC has no objection to the implementation of the described work. |
Debra Caillouet |
| 6/13/2012 |
Document, Report, or Work plan Review - other |
2011 Site Investigation Report, Eklutna Army Sites, Draft June 2012. Please provide an explanation of how the samples for SDG 1114876 were managed from collection on October 4, 2011 until they were received above temperature at the laboratory on the afternoon of October 5, 2011. |
Debra Caillouet |
| 10/5/2012 |
CERCLA SI |
2011 Site Investigation Report, Eklutna Army Sites, Final July 2012, received on October 3, 2012. The soil samples were analyzed for GRO, DRO, RRO, VOCs, and SVOCs. DRO was the only detected analyte at 50 and 80 mg/kg.
Test pits were excavated in four phases and samples were analyzed on an expedited schedule. DRO was detected in twelve of the samples. Detected concentrations ranged between 7 and 317 mg/kg.
Conclusions/Recommendations
The objectives of the 2011 Eklutna Army FUDS SI were to delineate the vertical and horizontal extent of petroleum contaminated soil at the future gravel extraction area and to develop a correlation between field screening results and petroleum contaminants. The lack of POL contamination prevented the development of a field screening/analytical result correlation and the extremely difficult direct push drilling conditions prevented the characterization of soil below 18 feet bgs.
The upper 18 feet of soil at the future gravel extraction area was evaluated through the excavation of forty-two test pits and collection of 352 soil samples (317 primary and 35 duplicates). Only one soil sample exceeded the ADEC Method 2 Migration to Groundwater Cleanup Level for DRO (test pit 17, 0-2 feet bgs) with 317 mg/kg. Widespread vadose zone contamination is not present within the future gravel extraction area. Given the extremely course and highly permeable nature of the vadose zone soil it is likely that very little if any vadose zone contamination exists at the site. Any impacted soil identified during future gravel extraction will likely be easily identified due a noticeable fuel odor.
the dissolved phase DRO plume will help identify the location of a former sources and any associated vadose zone contamination. The RI should also include the evaluation of smear zone soil within the DRO dissolved phase plume A PA will be completed during 2012 to identify all potential areas of concern at the Eklutna Army FUDS. Results from the PA will be used to develop a work plan for a RI.
A full RI is tentatively scheduled for FY 2013. During the RI, the evaluation of groundwater at the future gravel extraction area is recommended. Knowing the groundwater flow direction and extent of the dissolved phase DRO plume will help identify the location of a former sources and any associated vadose zone contamination. The RI should also include the evaluation of smear zone soil within the DRO dissolved phase plume. |
Debra Caillouet |
| 12/3/2012 |
Update or Other Action |
While not listed on the NPL, the Army Corps of Engineers must follow CERCLA process per E.O. 12580 [e.g. CERCLA Sections 104(a), (b), and (c)(4), 113(k), 117(a), and (c), 119, and 121) with respect to releases or threatened releases where either the release is on or the sole source of the release is from any facility or vessel under the jurisdiction, custody, or control of their departments. These functions must be exercised consistent with CERCLA Section 120 Federal Facilities.
State laws. -- State laws concerning removal and remedial action, including State laws regarding enforcement, shall apply to removal and remedial action at facilities owned or operated by a department, agency, or instrumentality of the United States when such facilities are not included on the National Priorities List. The preceding sentence shall not apply to the extent a State law would apply any standard or requirement to such facilities which is more stringent than the standards and requirements applicable to facilities which are not owned or operated by any such department, agency, or instrumentality].
|
Louis Howard |
| 4/5/2013 |
Document, Report, or Work plan Review - other |
Draft, March 2013, Remedial Investigation Work Plan, Eklutna Army Sites, Eklutna AK.
There are just a few comments on the document listed below.
1. Page 10, Dump Sites. Please add an explanation of what is planned to occur if
the dump sites do contain buried metallic debris.
2. Appendix A, 2.2. This work is being done under the contaminated sites rules so
the reference for the “qualified person” should be 18 AAC 75.990. Chapter 78 is for regulated underground storage tanks.
3. Appendix A, Table A-1. The preservation temperature for AK101 should be
4 ºC, not 25 ºC.
|
Debra Caillouet |
| 7/1/2013 |
Update or Other Action |
The objectives of the 2013 Eklutna Army Site Remedial Investigation are summarized below:
• Determine if the site features identified in the 1964 aerial photograph resulted in impacts
to the soil and groundwater
• Identify the contaminants of concern (COCs) that have impacted soil and groundwater
• Delineate the vertical and horizontal extent of contaminated soil
• Identify the horizontal extent of the contaminated groundwater
USACE-AK proposes utilizing a phased investigation approach for the 2013 RI.
Phase I will include evaluating the surface and subsurface soil in the vicinity of the site features identified on the 1964 aerial photograph. The former locations of the ASTs, potential USTs, drum piles, and transformers will be addressed through the excavation of test pits and collection of field screening/analytical samples. The 2 dump sites will first be evaluated via nonintrusive methods (geophysics). Conventional characterization methods (drill rig and split spoon sampling) are not being utilized due to the extremely coarse soil present at the site and the likelihood for poor sample recovery.
Phase II will include the installation of monitoring wells and the evaluation of groundwater and
smear zone soil at the site. Monitoring well locations will be based partially on the sample
results from the Phase I investigation. Delineation of the vertical and horizontal extent of contaminated soil may not be completed during the 2013 RI. Given the extremely coarse and highly permeable nature of the soil at the site it is likely that very little vadose zone contamination exists. This limited vadose zone contamination will likely be difficult to identify. The deep groundwater (35 feet bgs) and coarse soil also make it difficult to evaluate soil located within the smear zone.
The 2013 Phase II groundwater and smear zone soil data can be utilized to focus future investigations to identify the source of the groundwater contamination and extent of impacted soil. USACE-AK has programmed funding to perform additional investigation work at the Eklutna Army Site in 2014. |
Debra Caillouet |
| 7/26/2013 |
CERCLA RI Plan Approved |
Final April 2013, Remedial Investigation Work Plan, Eklutna Army Sites received.
|
Debra Caillouet |
| 4/4/2014 |
Update or Other Action |
RI WP Addendum received.
This work plan (WP) addendum is being prepared on behalf of the United States Army Corps of
Engineers, Alaska District (USACE-AK) and provides updates to the previously approved remedial
investigation (RI) WP for the Eklutna Army Site, a Formerly Used Defense Site (FUDS) located in
Eklutna, Alaska. Updates to the WP have become necessary due to delayed funding and elimination
of the USACE-AK drilling program, preventing “in-house” execution of the field work by the USACEAK.
As such, AECOM Technical Services, Inc. (AECOM) and its selected subcontractors will perform
all field activities and prepare the RI report. This project is being performed under AECOM’s
hazardous, toxic, or radioactive waste (HTRW) indefinite delivery/indefinite quantity (IDIQ) contract number W911KB-11-D-0001, Task Order 0011.
Although substantive changes to the intrusive sampling plan (e.g., soil and groundwater
investigation) are not foreseen, changes to the project schedule and personnel have necessitated
this addendum. In addition, a change in methodology for the geophysical survey of the former dump
sites is being proposed. With field execution of the WP no longer with USACE-AK, the originally
presented site safety and health plan has been incorporated into AECOM’s accident prevention plan.
This WP addendum is intended as a notification of updates and is presented as streamlined
“replacement text” to the previously approved WP dated April 2013.
Execution of RI field activities is now planned across the 2013 and 2014 field seasons. The
geophysical component of Phase I will be performed during the back-end of the 2013 season. All
remaining RI activities will be completed during the 2014 field season.
The geophysical survey will generally be performed as described in the previously approved WP;
however, use of EM-31 along orthogonal transacts on 25-foot centers is preferred over the use of
EM-61 along parallel transects on 10-foot centers. Although both techniques are capable of
identifying the presence of buried metallic debris, EM-31 is better suited for the intended purpose of this project to verify completion of previously reported removal efforts within each former dump site.
EM-31 has greater penetration, and used in conjunction with orthogonally placed transects, will
provide greater aerial coverage within each dump site. The transmitter/receiver coil separation for the EM-31 yields a field of view across each transect of 12.5 feet, compared to only about 3.3 feet for the EM-61. Using EM-31 along orthogonally oriented transects on 25-foot centers yields an area of 625 square feet between four adjacent transects.
The field of view not reached across this area is 156 square feet, or roughly 25% of the area not sampled. Similarly, parallel oriented transects using the EM-61 on 10-foot centers yields an area of 100 square feet between two adjacently squared transects. The field of view not reached across this area is 66 square feet, or 66% of the area not sampled.
Current DoD ELAP and ADEC certifications for Test America have been included as Attachment A. It
is noted that the current ADEC certification expires before fieldwork begins in July 2014, and as
such, an email from the laboratory attesting their intention to maintain certification or obtain
recertification prior to performance of work under this task order has also been included. The
renewed certification will be provided/ incorporated upon receipt from the lab.
|
Debra Caillouet |
| 4/15/2014 |
Document, Report, or Work plan Review - other |
Final RI work plan addendum approved. |
Debra Caillouet |
| 5/28/2014 |
Exposure Tracking Model Ranking |
Initial ranking with ETM completed for source area id: 79074 name: Eklutna Army Sites |
Debra Caillouet |
| 6/15/2015 |
Update or Other Action |
Draft RI Phase I report received. Deviations from the WP: During the April 2014 Stakeholder Meeting to present the results of the geophysical survey & inform the community of the upcoming RI schedule, ADEC had requested that the Resource Conservation & Recovery Act (RCRA)-8 replace the metals suite as presented in the RI WP & its Addendum. It was agreed that mercury would only be required for the dump site locations.
Location STR-72 was not sampled due to a large gravel overburden stockpile (12 to 15 ft high) placed on top of the location from current mining activities. Excavating the gravel to previous grade was impractical & the nearest sampling location representing historical grade would have been too far removed (> 30 ft) to assess the feature of interest. This location was discussed during the above-mentioned Stakeholder Meeting as it was known at that time (features surveyed) that this area would likely be inaccessible unless site conditions changed in time for the sampling event. All other locations were sampled according to the WP.
The sample submitted to the laboratory from the DP-NE-3 location was not analyzed for volatile compounds; GRO & VOC were erroneously left unchecked on the COC form. The capillary fringe could not be sampled at all well locations due to insufficient recovery for analytical analysis (e.g., longitudinal split cobble in the sample shoe) or no recovery at all. Soil samples were not collected during well installation activities from MW-4, MW-5, MW-9, MW-10, & MW-14.
The following recommendations for the site have been developed following evaluation of both the Phase 1 RI & previous data collected at the site to date.
Soils : Collect step-out soil samples around the former NW drum pile (& as applicable at TP-06, TP-12, TP-17, TP-48) to delineate the horizontal & vertical extent of POL contamination. Collect soil samples from across the site to evaluate the horizontal & vertical extent of chlorinated solvents contamination in soil. Collect soil samples for total organic carbon to evaluate fate & transport of the VOCs in subsurface soils. Collect soil samples around UST-02 to delineate the vertical & horizontal extent of lead contamination.
Groundwater: Evaluate the horizontal extent of chlorinated solvents in GW to the north & east of the site. Resample monitoring wells MW-08, MW-14, & MW-15 & analyze the samples for both total & dissolved metals to evaluate the source of the metals observed during the RI.
Air: Install multi-depth probes at & around identified exceedances & collect active soil gas samples for analysis of VOCs & evaluate whether or not volatilization of chlorinated solvents from subsurface soils & groundwater is a risk for impacting outdoor or future indoor air at the site.
The proposed scope & sampling locations for follow-on work considerations will be presented for regulatory review & approval in a forthcoming work plan for a Phase II RI. |
Debra Caillouet |
| 7/6/2015 |
Document, Report, or Work plan Review - other |
The Draft Phase 1 Remedial Investigation, Eklutna Army Sites, Eklutna Alaska, June 2105 was reviewed. Minor comment was provided to the Corps. The report documents widespread chlorinated VOC contamination in the aquifer. Additional investigation is needed to determine the complete extent. The groundwater is not used as a drinking water source currently.
The report also does not contain the laboratory data reports. Staff requested USACE to provide these with the final so that the validity of the check lists may be verified.
While not listed on the NPL, Eklutna Army Sites must follow CERCLA process per E.O. 12580 [e.g. CERCLA Sections 104(a), (b), and (c)(4), 113(k), 117(a), and (c), 119, and 121) with respect to releases or threatened releases where either the release is on or the sole source of the release is from any facility or vessel under the jurisdiction, custody, or control of their departments. These functions must be exercised consistent with CERCLA Section 120 Federal Facilities.
State laws. -- State laws concerning removal and remedial action, including State laws regarding enforcement, shall apply to removal and remedial action at facilities owned or operated by a department, agency, or instrumentality of the United States when such facilities are not included on the National Priorities List. The preceding sentence shall not apply to the extent a State law would apply any standard or requirement to such facilities which is more stringent than the standards and requirements applicable to facilities which are not owned or operated by any such department, agency, or instrumentality.].
|
Debra Caillouet |
| 8/3/2015 |
Update or Other Action |
Phase II RI WP draft received. Temporary Project Manager is Dennis Shepard due to D. Caillouet's retirement from ADEC in July 2015.
Phase II RI field activities will be performed using an iterative approach across three separate
mobilizations during the 2015 and 2016 field seasons.
Mobilization 1 will include a PSG survey and soil collection for VOCs. A limited number of groundwater monitoring wells will also be installed during this mobilization to begin filling data gaps in addressing the lateral and vertical extent of the dissolved-phase plume identified during Phase I. Ideally, this initial effort can be conducted during the fall of 2015 to avoid a later start during 2016 while waiting for subsurface thawing of the soils in order to optimize the PSG sampling.
Mobilization 2 will address the data gaps determined from Mobilization 1 to complete the delineation of the extent of VOC contaminated soil through soil sample collection and analytical analyses. Limited soil sampling for lead at a small point source identified during Phase I will also be collected at this time along with total organic carbon (TOC) for modelling purposes. During this mobilization, USACE will also self-perform a limited UVOST soil screening effort with the objective to fully delineate four isolated occurrences of DRO contamination identified during Phase 1 of the RI Additional groundwater monitoring wells will be installed as needed to complete horizontal and vertical delineation of the dissolved-phase plume.
Mobilization 3 will collect active soil vapor samples to help evaluate risk posed to human receptors, and to fill any remaining data gaps noted from previous mobilizations. Mobilization 3 may include installing and sampling additional deeper groundwater monitoring well; and installing soil-vapor monitoring points and collecting active soil gas samples. Mobilization 2 and 3 are proposed to be conducted during the 2016 field season. Mobilization 2 is scheduled in the spring and Mobilization 3 in the fall with sufficient time between the two events to allow evaluation of
the earlier data to optimize the sampling design of the final mobilization. |
Dennis Shepard |
| 9/16/2015 |
Document, Report, or Work plan Review - other |
DEC provided preliminary review comments for the Draft Work Plan Phase II Remedial Investigation (Work Plan), Eklutna Army Sites, Eklutna, Alaska, August 2015. The Work Plan is divided into three separately scheduled mobilization efforts. Due to the iterative mobilization approach that is proposed, the Department will provide approval of the Work Plan Mobilization 1, DEC will review and provide comments on Mobilization 1 results and remaining data gaps prior to the approval/startup of Mobilization 2. The Department will review results and provide comments in this way prior to each Mobilization proposed under the Work Plan. |
Dennis Shepard |
| 10/15/2015 |
Update or Other Action |
Staff received the Draft Screening Level Human Health Risk Assessment Work Plan Phase II Remedial Investigation Eklutna Army Sites (F10AK009701) Formerly Used Defense Site Eklutna, Alaska for review and comment. New Project manager assigned to site is Louis Howard for ADEC taking over from Dennis Shepard (temporary project manager).
The risk assessment work plan (RAWP) contained herein describes the activities that will be completed to assess human health risk for the current use scenario only (limited recreation and subsistence) for the portion of the site outside of the active quarry areas.
The overall objectives of this RAWP are 1) to evaluate the adequacy of the data collection proposed in the Phase II RI Work Plan (WP) for completing a human health screening level risk evaluation (SLRE); 2) identify the potential human receptors and complete exposure pathways at the Site; and 3) to identify the methods to be used to assess the potential for unacceptable adverse effects to human health based on comparison of site concentrations to generic screening concentrations using a screening approach. This SLRE approach is intended to provide information necessary to evaluate the need for more a detailed risk evaluation and/or to provide information necessary to support risk management decisions. |
Louis Howard |
| 11/12/2015 |
Update or Other Action |
Final work plan for Phase II RI received.
Phase II RI field activities will be performed using an iterative approach across three separate mobilizations during the 2015 & 2016 field seasons. Contamination at the site is associated with activities at the former military supply & storage area. The site formerly contained two dump sites, five drum piles, & two distinct material storage yards. Potential release mechanisms for COPCs include surface &/or secondary subsurface releases & associated leaching.
Surface (0-2 ft) & subsurface (>2 ft) soil & GW are the primary affected media. Generally, soils at the site consist of fine to coarse gravel & sands with highly variable amounts of silts & clays. Cobbles up to 8 inches in diameter were regularly observed during excavation of test pits & trenches. Contamination in soil is poorly distributed within the observed soil profile, adsorbing strongly to the finer grained materials. The distribution of fines in the formation is also very heterogeneous which produces an uneven mechanism for secondary releases to the GW.
Mobilization 1 will include a PSG survey & soil collection for VOCs. A limited number of GW monitoring wells will also be installed during this mobilization to begin filling data gaps in addressing the lateral & vertical extent of the dissolved-phase plume identified during Phase I. Ideally, this initial effort can be conducted during the fall of 2015 to avoid a later start during 2016 while waiting for subsurface thawing of the soils in order to optimize the PSG sampling.
Mobilization 2 will address the data gaps determined from Mobilization 1 to complete the delineation of the extent of VOC contaminated soil through soil sample collection & analytical analyses. Limited soil sampling for lead at a small point source identified during Phase I will also be collected at this time along with total organic carbon (TOC) for modelling purposes. During this mobilization, USACE will also self-perform a limited UVOST soil screening effort with the objective to fully delineate four isolated occurrences of DRO contamination identified during Phase 1 of the RI Additional GW monitoring wells will be installed as needed to complete horizontal & vertical delineation of the dissolved-phase plume. The main purpose of Mobilization 3 is to collect active soil vapor samples to help evaluate risk posed to human receptors, & to fill any remaining data gaps noted from previous mobilizations.
Mobilization 3 may include installing & sampling additional deeper GW monitoring well; & installing soil-vapor monitoring points & collecting active soil gas samples. Mobilization 2 & 3 are proposed to be conducted during the 2016 field season. Mobilization 2 is scheduled in the spring & Mobilization 3 in the fall with sufficient time between the two events to allow evaluation of the earlier data to optimize the sampling design of the final mobilization.
See site file for additional information. |
Louis Howard |
| 11/30/2015 |
Document, Report, or Work plan Review - other |
Staff provided comments on the Draft Screening Level Human Health Risk Assessment Work Plan Phase II Remedial Investigation Eklutna Army Sites.
Staff requested that the work plan follow the CERCLA process for risk assessment as required by DoD E.O. 12580 and the NCP. Additional investigation of the area under the quarried tailings pile should be conducted once the pile is removed. Currently, the area is being excluded from investigation to the presence of the pile. Additional comments were made regarding chemicals of potential concern (COPCs) which should be based off one-tenth (1/10th) of the cleanup values since multiple pathways and chemicals are present on site. Finally, staff pointed out that groundwater contamination extent has not been characterized adequately to support any evaluation or assessment of risk in the vicinity of wells: MW-21, MW-10, MW-19, MW-20, and MW-12.
See site file for additional information. |
Louis Howard |
| 12/28/2015 |
Update or Other Action |
Draft Final Phase I Remedial Investigation (RI) received for review & comment.
The RI incorporated a phased approach in which site reconnaissance, vegetation clearing, & geophysical survey activities were performed to optimize the sampling design for the soil & GW investigations. Follow-on soil & GW sampling was also conducted to initiate vertical characterization of the aquifer in response to ADEC comments on the Draft RI report (Appendix G).
This report presents the procedures, results, & findings of the RI conducted from 2013 to 2015. Continuing investigation of the project is being performed under an alternate contract & task order (see Final WP Phase II RI [AECOM 2015]). Monitoring wells were installed at 21 locations across the site to determine the nature & extent of GW contamination, one of which was installed as a cluster well with three separate screened intervals to initiate vertical characterization of TCE contamination.
GW samples from the initial 18 monitoring wells were collected & submitted for DRO, RRO, PAHs, VOCs, & target metals; GW samples from the subsequent follow-on investigation were collected & submitted for VOCs only. Additionally, samples collected from monitoring wells within the two dump sites (MW06 & MW07) were also analyzed for mercury. The following is a summary of COPCs by chemical class.
POLs. No analytes were detected at concentrations above the PALs.
PAHs. No analytes were detected at concentrations above the PALs.
VOCs. TCE was detected above the 5 microgram per liter (µg/L) PAL in wells MW-02, MW-04 through MW-10, MW-12, & MW-19 through MW-21 ranging from 13 µg/L at MW-20 to 380 µg/L at MW-19 & MW-21. Additionally, both deeper screened intervals from the MW-19 cluster (MW-19A & MW-19B) had TCE exceedances of 390 µg/L & 340 µg/L, respectively. 1,1,2,2-Tetrachloroethane was detected above the 4.3 µg/L PAL in wells MW-04, MW-06 through MW-10, MW-12, MW-19, & MW-21 at concentrations ranging from 7.3 µg/L in MW-08 to 19 µg/L in MW-10.
Additionally, one deeper screened interval from the MW-19 cluster (MW-19A), had a 1,1,2,2- Tetrachloroethane exceedance of 7.1 µg/L. No other VOCs exceeded PALs. Metals. Total chromium was detected above the 100 µg/L PAL in wells MW-08, MW-14, & MW-15. Concentrations ranged from 130 µg/L in MW-08 to 480 µg/L in MW-15. Nickel was detected above the 100 µg/L PAL in wells MW-14 & MW-15 at 150 µg/L & 280 µg/L, respectively. It is noted that turbidity at these locations may have contributed to the above, but filtered samples are not available to further evaluate this. No other metal analyte exceeded PALs. |
Louis Howard |
| 1/11/2016 |
Document, Report, or Work plan Review - other |
Staff provided review comments on the draft final Phase I RI report.
Main comments were regarding requesting that 1,4-Dioxane be sampled for at the site, use of the Field Sampling Guidance for soil sampling test pits' sidewalls, public domain modeling of fate and transport of VOCs in soils, use of most current EPA RSLs when screening COPCS, use of 1/10th of the most stringent applicable pathway instead of cleanup levels when screening COPCs and finally, rejection of ND data when holding times are exceeded. This last comment is based on the EPA's National Functional Guidelines for Superfund Organic Methods Data Review (August 2014).
See site file for additional information. |
Louis Howard |
| 4/28/2016 |
Document, Report, or Work plan Review - other |
The Alaska Department of Environmental Conservation (ADEC) has received the WP Addendum for mobilization #2 for expedited review and comment. ADEC is providing the expedited review as a favor and the CORPS and its contractor should not expect such reviews as standard operating procedure. The addendum satisfactorily incorporated the items discussed during the April 4, 2016 scoping meeting held with you and your contractor prior to this document submittal. The work plan addendum meets the applicable requirements of 18 AAC 75.335, Site Characterization and is approved for implementation. |
Louis Howard |
| 9/23/2016 |
Document, Report, or Work plan Review - other |
Staff reviewed and approved the draft work plan addendum for mobilization #3. The document formalizes and outlines the approach discussed during an August 30, 2016 meeting. ADEC has reviewed the document and concurs it accurately reflects what was discussed and the approach to be taken at the site. The work plan addendum is approved by ADEC and it may be finalized for implementation as written. |
Louis Howard |
| 12/1/2016 |
Meeting or Teleconference Held |
CS managers participate in the annual FUDS site management action plan meeting. The purpose of the is to collaborate with FUDS management on site progress and prioritization for all of the formerly used defense sites. FUDS prioritization is based on risk, congressional interest, state input and proximity to other sites on the prioritization list. FUDS has increased environmental restoration funding in Alaska for the 2017 and 2018 field seasons to meet National goals for site progress. |
Darren Mulkey |
| 3/16/2017 |
Document, Report, or Work plan Review - other |
Staff provided comments on the draft work plan for metal magnetometer screening for drums at the site. Staff requested a map be provided with grid line overlays where the survey work will be conducted on the 32 acres of the site. ADEC will require that the qualified environmental professional be on-site at all times to directly supervise the tribal crew during any training and all field work at the site which is conducted by anyone else but the qualified environmental professional.
See site file for additional information. |
Louis Howard |
| 8/8/2017 |
Document, Report, or Work plan Review - other |
Staff commented on the site activity report for metal detection work to locate buried drums. ADEC agrees that there are no buried drums within the limitations of the magnetometer’s ability to detect them below the ground surface (magnetometer is limited to eight feet below ground surface-maximum depth of detection). Staff had no objections to screening for drums on the other areas of the site. |
Louis Howard |
| 9/18/2017 |
Update or Other Action |
Phase II RI received for review & comment. The lateral extent of DRO at the former NW drum pile has been delineated. Vertical delineation within the vadose zone is incomplete at the center location. Multiple PAHs were detected at concentrations exceeding the applicable PAL in surface sample RAS06, collected to support the human health SLRE. For benzo(a)anthracene, benzo(a)pyrene, benzo(a)fluoranthene, dibenz(a,h)anthracene, & indeno[g,h,i-cd)pyrene, this was the only location with exceedances for these compounds. This sample is located in an area with significant post-military use (vehicular traffic, & reasonably close to the railroad corridor). These exceedances have not been delineated laterally or vertically.
Chlorinated solvent impacts are widespread in soil & soil gas across the Site. The primary list of solvent compounds with exceedances in soil include TCE & associated chlorinated solvents that are either breakdown products or impurities in the production of TCE or PCA (e.g., PCE, 1,1,2-TCA, cis-1,2-DCE, & 1,2-DCA, & possibly hexachlorobutadiene). The assumed source of the TCE plume is well defined in soil except to the east, although a topographic incline associated with a gravel pad shelf will complicate further delineation in that direction.
Additional soil borings & a monitoring well may be considered to further evaluate the suspected northwest source area in the vicinity of the north dump site. This should include evaluation of the area immediately north of wells MW09 & MW20 based on observed PSG response & the current understanding of the surface topography; GW flow at the site; & advection processes. The investigation should also include the area located south of PSG 112 in the vicinity of MW06 & the historical north dump site for additional source area refinement. Additional PSG surveys outside the existing survey area should be considered for screening purposes prior to drill program implementation, in addition to field reconnaissance for the presence of historical disturbances. A sample grid of shallow soil samples should also be considered as an alternative near PSG112. Soil samples should be evaluated for VOCs. Based on existing shallow soil sample trends, samples should be collected at depths of two feet or greater to acquire residual source (e.g., recoverable) material representativeness.
To the extent practicable, a deep & shallow well monitoring well should be installed northnorthwest of MW36 to evaluate the presence of VOCs in soil & GW, & subsurface soil characterization (e.g., confining layers). It is recommended that the well cluster be installed within a localized area of contrasting vegetation located immediately adjacent to Knik Arm. It is uncertain whether the area of heavier (contrasting) vegetation is attributed to variation in topographic relief or contributing presence of freshwater from surface or shallow GW sources. Furthermore, the well cluster would represent a northernmost point of compliance for shallow & deep GW impairments (if any). Mud rotary drilling methods should be considered for deep well installation.
See site file for additional information. |
Louis Howard |
| 9/19/2017 |
Update or Other Action |
UVOST investigation report received for review and comment. The objective of the 2016 UVOST investigation was to delineate the DRO contamination identified during previous investigations at seven DRO exceedance locations (TP-48, DP-NW-1/DP-NW-2/DP-NW-3, TP-12, TP-06, TP-17, TP-01, and DP-SC-2). Generally the RI objective was achieved through the completion of 34 UVOST probes and collection of 15 primary site characterization soil samples. Additional investigation is warranted to delineate the impacted soil at the DP-NW-1/DP-NW-2/ DP-NW-3 area.
See site file for additional information. |
Louis Howard |
| 9/28/2017 |
Document, Report, or Work plan Review - other |
Staff provided comments on the UVOST report. Main comments were regarding chlorinated solvent contamination requiring additional delineation for nature and extent at several sampling points and to conduct sampling for field duplicates 1/10 samples per method, per matrix and per day in the field.
See site file for additional information. |
Louis Howard |
| 10/16/2017 |
Document, Report, or Work plan Review - other |
Staff provided comments on the draft Phase II Remedial Investigation Report. Main comment was that all characterization efforts at all the drum sites did not include PCBs. Groundwater is stated as not being used for potable purposes, however, an 18 AAC 75.350 determination has not been requested and approved for this site by ADEC. Finally, consistent with other federal facilities where human health screening is conducted, for PSLs used for soil, the June 2017 EPA Region 10 RSLs (TR=1E-06 and THQ=0.1) for resident soil shall be used as the primary project screening level (PSL). In cases where there is not an EPA RSL, this investigation shall utilize one-tenth the ADEC Method Two Human Health cleanup level from Table B1 (2017) or ingestion/inhalation (Table B2) for the media under investigation.
It is important that the laboratory’s limits of detections (LODs) for investigated analytes be able to meet the ADEC clean-up level for migration to groundwater when it is technically possible. An additional column for migration to groundwater will be available for comparison of laboratory limits.
See site file for additional information. |
Louis Howard |
| 11/27/2018 |
Document, Report, or Work plan Review - other |
Staff commented on the draft phase III work plan. Main comments were to revise the hierarchy used for screening levels for soil & water. EPA Regional Screening Levels (RSLs) will be used for soil & groundwater first (total hazard quotient 0.1 & total risk 10-6) & where no RSL exists, 1/10th the human health level for soil & 1/10th table C for groundwater will be used.
Soil data will also compared to the ADEC migration to groundwater cleanup levels (ADEC October 27, 2018) for use in site delineation & to provide additional information regarding the potential migration of contaminants.
In the case of fuels, results will be compared to the soil ingestion criteria for the under 40-inch zone from Table B2 (ADEC October 27, 2018).
Groundwater sample results will also be compared to ADEC Table C groundwater human health cleanup levels (ADEC October 27, 2018) in order to determine plume extents under State of Alaska regulations as a basis for the feasibility study (FS).
See site file for additional information. |
Louis Howard |
| 8/31/2020 |
CERCLA RI Plan Approved |
Approved the Phase III Remedial Investigation Work Plan Addendum. Risk Assessment Work Plan to follow. |
Darren Mulkey |
| 6/13/2022 |
Document, Report, or Work plan Review - other |
6/7/2022 DEC approved the Final Phase III Remedial Investigation Work Plan Addendum dated September 2021. |
Daniela Fawcett |
| 4/6/2023 |
Document, Report, or Work plan Review - other |
DEC received a request from the U.S. Army Corp of Engineers for input on selecting applicable or relevant and appropriate requirements (ARARs) for the forthcoming draft feasibility study (FS) for the Eklutna Army Sites. Additional ARARs may be identified when USACE provides DEC with a draft FS for review and comment. Date for the FS to be provided is to be determined since the draft Phase III remedial investigation (RI)/risk assessment (RA) is in review. |
Erica Blake |
| 4/18/2023 |
Document, Report, or Work plan Review - other |
DEC submitted comments regarding the Phase III Remedial Investigation and Baseline Risk Assessment Report Eklutna Army Formerly Used Defense Sites Eklutna, Alaska, Draft, dated March 2023. The report presents a baseline risk assessment and describes the remedial investigation activities conducted during the 2019 and 2020 field seasons in Eklutna, Alaska. The results of the report indicate that solvents and fuel related compounds are present throughout the site above project screening levels. Lead contamination exceeding DEC’s most stringent promulgated cleanup level was also identified at the site. The report recommended an evaluation of remedial alternatives during a feasibility study to address the existing contamination in soil, groundwater, and ambient air. |
Ginna Quesada |
| 8/23/2023 |
Document, Report, or Work plan Review - other |
DEC submitted responses to comments for the Phase III Remedial Investigation and Baseline Risk Assessment Report Eklutna Army Formerly Used Defense Sites Eklutna, Alaska, Draft Final, dated July 2023. |
Ginna Quesada |
| 8/16/2024 |
Document, Report, or Work plan Review - other |
DEC received a document titled Draft High-Resolution Site Characterization Work Plan, Eklutna Army Formerly Used Defense Sites, Eklutna, AK on July 23rd, 2024. This work plan described the High-Resolution Site Characteristic (HRSC) activities to be conducted at the Eklutna Army Sites located near the Native Village of Eklutna. This plan outlines the further characterization of chemicals of concern that have been identified in previous investigations.
Comments were generated for the document and sent back to the PM, on August 16, 2024. |
Matthew Fleetwood |
| 10/3/2024 |
Document, Report, or Work plan Review - other |
DEC approved the High Resolution Site Characterization Work Plan, dated October 3, 2024. |
Matthew Fleetwood |
