| Action Date |
Action |
Description |
DEC Staff |
| 4/21/1992 |
Update or Other Action |
Air Force cuts use of benzene Jet Fuels (Anchorage Times B3)
The U.S. Air Force is switching jet fuels to eliminate hazardous benzene emissions and reduce fuel handling risks, officials said Monday. Starting May 4 [1992] fighter jets at Elmendorf will tank up on JP-5, a kerosene-based fuel that contains no benzene, and in October [1992] will switch to JP-8, another kerosene-based fuel without benzene, said Col. Dennis Beck, deputy chief of staff logistics with the 11th Air Force.
The entire Air Force should be converted to JP-8 within two years, he said. Up to now the Air Force fueled its aircraft with JP-4, a naphtha-based fuel that contains low molecular
weight hydrocarbons such as the cancer-causing benzene.
The switch in fuels should decrease benzene vapor emissions in the tank farms, which supply Elmendorfs fuel, by 10 to 12 percent, said Lt. Col. Robert Dreyer, commander of the Defense Fuel Office-
Alaska.
But Dreyer said it could take 12 to 18 months to eliminate the JP-4 stockpile. This year the Air Force signed fuel contracts totaling 52 million gallons, he said.
Although benzene vapor emissions are a consideration, "the prime reason for converting to JP-8 is, it's a much safer fuel with lower volatility," Beck said. "We're moving toward a common battlefield fuel that can be used by aircraft and diesel-powered main battle tanks, plus in the process we're solving environmental problems by doing away with emissions." But JP-8 has several drawbacks, including reduced aircraft mileage, Beck said.
"It normally takes more fuel, but not significantly more," he said. 'The offset, it's a much safer operation in peacetime and combat, because it does not ignite like JP-4." |
Louis Howard |
| 3/26/1993 |
Update or Other Action |
DOD, EPA and ADEC joint Technical Memorandum of understanding signed concerning the Base-wide Groundwater (GW) signed by: EPA Marcia Combes, ADEC Jennifer Roberts RPM and USAF Joseph Williamson Chief Environmental Programs & Restoration. Due to the base-wide GW study and the FY92 field work that occurred at Operable Units (OUs) 1, 2, and 5 it appears a large portion of the GW flows into OU5 (attach. 1-contour map). Based on this fact, Elmendorf (EAFB) will move all upgradient GW into the OU5 Feasibility Study, Proposed Plan and Record of Decision (ROD). This means addressing all GW from upgradient sources (CERCLA (ST20, OUs 3 and 4) and OUs 1 and portions of OU2) and SERA) at OU5 instead of at each individual source area (see attach. 2-Area Map). Sites with free phased product would be looked at to see if there is an available technology to clean them up in a cost effective way. Soil contamination would be addressed at the source areas. NOTE: addressed at the source areas is interpreted by ADEC as removal through excavation or active treatment systems (e.g. high vacuum extraction, bioventing, etc...). |
Jennifer Roberts |
| 1/19/1995 |
Update or Other Action |
OU5 Groundwater Modeling Report received. The objectives of the modeling task were to: Evaluate the movement of contaminants across Elmendorf AFB and within Operable Unit (OU) 5; Predict contaminant migration over the next 30 years; and Determine if selected receptor points along Ship Creek and an unnamed beaver pond will be impacted by contamination. A 3 dimensional finite element model (SALT) developed at the University of Waterloo was selected because of its versatility in handling complex geology and boundary conditions. Radian Corporation modified the model to improve the program's efficiency and to include contaminant decay and site specific boundary conditions along Ship Creek. This modified version called SALT 3, consists of groundwater flow and contaminant transport models. The hydrogeology of the modeled area was evaluated using lithologic data collected from all available boreholes within the modeled area and water level data collected from shallow water table monitoring wells in March and September 1993.
After a review of the groundwater quality data from September 1993 groundwater sampling and available OU 1, 2, and SERA site data, benzene and trichloroethene were selected as representative compounds for this modeling effort. Benzene and TCE were selected due to their potential health impacts. As metals and semivolatile compounds were only sporadically detected at concentrations near maximum contaminant levels (MCLs) they are not constituents of environmental concern in much of the aquifer beneath EAFB and were not modeled.
Concentrations in the recharge over the water table was set to zero except for at source areas. Since improvement in soil quality is expected over time, the sources were assumed to cease contributing benzene and TCE to groundwater afar five years. All concentrations in the recharge zone were therefore set to zero at the end of the first five years.
The conclusions of the base case simulations show that benzene and TCE will migrate toward the south. However, the concentrations of these contaminants will decline over time. Because of infiltration, there may be some localized areas that experience a temporary increase in concentration as a "pulse" migrates toward the south. Benzene will be detectable in groundwater for over 20 years, however, the concentrations in groundwater base wide should be below the MCL after 15 years (1993-2008). TCE concentrations will be detectable in groundwater after 30 years (2023) and should be less than the MCL base wide after 20 years (2013).
Benzene and TCE will spread and migrate toward the south from identified source areas. Concentrations in groundwater flowing toward Ship Creek and the unnamed beaver pond should not exceed 1 ug/L over the period modeled. The model predicts that the concentrations of these compounds in groundwater near surface water bodies will be approximately 1 ug/L after 5 years (1998) and will then steadily decline over time. The results of the groundwater modeling effort indicate that the groundwater can be remediated naturally (MNA) in all OUs without any predicted increase impact to sensitive receptors in OU5. The model predicted, that in five years, benzene and TCE concentrations in OU5 from upgradient sources will be above 1 ug/L but less than 10 ug/L. In 10 years (2003), the concentration of these compounds is predicted to be less than 1 ug/L in OU5, indicating a measurable improvement in water quality over time. |
Louis Howard |
| 10/17/1996 |
Update or Other Action |
Air Force memo: Restricted Use of the Shallow Aquifer on EAFB signed by William R. Hanson P.E. GM-14 Chief Environmental Flight dated October 17, 1996 Memorandum for 3 SPTG/CEC/CEO from 3 SPTG/CEV.
1) Due to the contamination and commitments to EPA/DEC the use of the shallow aquifer for any purpose on is not allowed. Attached Facilities Board minutes-03/29/1994 0930 Item 9 has Mr. William Hanson, briefing the Board on the policy to not use the shallow aquifer due to contamination. The Board approved this policy. Minutes approved by Thomas R. Case Brigadier General USAF Commander. The IRP has RODs for OUs 3 and 6 which require, the aquifer remain unused. 2) Personnel in the review process within CES must be aware of these policies and review them on a recurring basis. It is imperative this restriction be recognized & observed during engineer reviews & operations. |
Jennifer Roberts |
| 12/27/1996 |
Update or Other Action |
The 10 inch pipeline was extensively damaged in the 1964 earthquake, was abandoned shortly after the earthquake. Letter from the AF received on the addition of site PL81 (inactive 10-inch diameter pipeline) to the State Elmendorf Restoration Agreement (SERA) Program. Concurrence given same day. PL81 is a petroleum, oil, and lubricant pipeline that runs from the spaghetti works at the Port of Anchorage distribution system to Valve Pit #14 north of the east/west runway.
It was constructed in 1942 to transmit AVGAS and JP-4 from the Port of Anchorage to Elmendorf AFB. In 1944, JP-1 was introduced as the first jet fuel specification in the United States; this fuel was used by early military jets. The specification defined a kerosene type fuel with a maximum freezing point of -77°F. JP-3 was introduced in 1947. Fractions from the gasoline boiling range were introduced to increase availability and provide better starting characteristics. JP-3 did not have a flash point requirement. In 1951, the JP-4 fuel specification was adopted and became the primary jet fuel of the U.S. military for the next 30 years. JP-4 was called a wide-cut fuel rather than a kerosene, because the boiling range broadly overlapped both gasoline and kerosene. Again, there was no flash point requirement.
*Avgas has a lower volatility than mogas. The particular mixtures in use today are the same as when they were first developed in the 1950s and 1960s, and therefore the high-octane ratings are achieved by the addition of tetra-ethyl lead (TEL), a fairly toxic substance that was phased out for car use in most countries in the 1980s. Antiknock Additive-The most important avgas additive is TEL. It is added as part of a mixture that also contains ethylene dibromide (EDB) and dye. EDB acts as a scavenger for lead.
When avgas is burned in an engine, the lead in TEL is converted to lead oxide. Without a scavenger, lead oxide deposits would quickly collect on the valves and spark plugs. EDB reacts with the lead oxide as it forms and converts it to a mixture of lead bromide and lead oxybromides. Because these compounds are volatile, they are exhausted from the engine along with the rest of the combustion products. Just enough EDB is added to react with all of the lead.
Avgas is currently available in several grades with differing maximum lead concentrations. Since TEL is a rather expensive additive, a minimum amount of it is typically added to the fuel to bring it up to the required octane rating so actual concentrations are often lower than the maximum. Avgas 80/87 (dyed red) has the lowest lead content at a maximum of 0.5 gram lead per US gallon, and is only used in very low compression ratio engines. Avgas 100/130 (dyed green) is a higher octane grade aviation gasoline, containing a maximum of 4 gram of lead per US gallon, maximum 1.12 gram/liter. Grade 100 has a maximum 1.12 grams of lead per liter and is dyed green. 100LL "low lead" was designed to replace avgas 100/130. Avgas 100LL (dyed blue) contains a maximum of 2 gram of lead per US gallon, or maximum 0.56 gram/liter, and is the most commonly available and used aviation gasoline.
In 1996, the U.S. Environmental Protection Agency (EPA) banned lead in motor gasoline. Although avgas was not included in the ban, concerns that the use of lead in avgas would eventually be restricted led the industry to begin looking for unleaded replacement fuels in the early 1990s.
Naphthalene is a white solid or a liquid that occurs naturally in fossil fuels such as coal and crude oil and is best known as the primary ingredient of mothballs. It is extracted from these sources for other uses including jet fuel (as 1-3% of the fuel JP-4, JP-8, and commercial aviation gas or AvGas) |
Louis Howard |
| 3/21/1997 |
Update or Other Action |
Letter sent to Larry Underbakke in response to phone call on 3/19/1997 regarding the disposition of excavated contaminated soils encountered during upcoming summer's PL81 (inactive 10-inch) pipeline project in the vicinity of the Port of Anchorage but on the northern portion of PL81. All contaminated soils removed from the ground during the closure or decommissioning of the PL81 project must be done in accordance with 18 AAC 78.311 Soil Storage and Disposal.
The rationale for the need to excavate all excavated petroleum contaminated soil is based on previous experience with other Elmendorf Air Force Base (EAFB) sites where follow-up work was not conducted.
Specifically, Tank #805 at building 24-805 (new Bldg. # is 4913) UST failed a tightness test in 1994 and was removed from the ground. Tanks 96-104 associated with building 22-013 (new bldg.# is 4347) were also removed from the ground in 1994. Petroleum contaminated soil was excavated during removal of the tanks. The Air Force requested approval to place contaminated soil back in the ground for both of these sites and subsequently numerous others. DEC approval was granted on the condition corrective action would be started at each site soon thereafter. The Air Force had committed to doing this work under Phase IV of the SERA (dissolved as of 10/21/2002). However, DEC has been informed that work plans for risk assessment or corrective action at each site had not been developed. This is a violation of the corrective action requirements outlined in the UST regulations and our prior agreements with the Air Force.
Based on the above example and the fact that funding for DOD environmental cleanups is being reduced, DEC is no longer in a position to allow contaminated soil to be placed back in the ground with the hope it will be remediated in a timely manner. |
Louis Howard |
| 4/18/1997 |
Update or Other Action |
Letter to Roger Graves Port of Anchorage regarding phone call on April 17, 1997. Concurrence received by Port of Anchorage to let Elmendorf AFB for this single event, due to unique conditions of the project in the right of way, other ongoing investigations in the area and associated commercial traffic, allow the return of soils back into excavation where it occurs on Port of Anchorage property. |
Louis Howard |
| 6/25/1997 |
Update or Other Action |
Fax request for approval of remediation of 4 drums of POL contaminated soils generated during drilling operations (3 from OU4 bioventing study and 1 from PL81). ADEC granted approval for transport to Alaska Soil Recycling. |
Louis Howard |
| 8/7/1997 |
Update or Other Action |
60% Design submittal PL81 Pipeline Demolition project comment letter sent. ADEC comments requested free phase fuel encountered during excavation or demolition activities shall be recovered before work is allowed to continue. NOTE to File: “free product” means a concentration of a hazardous substance that is present as a nonaqueous phase liquid; for purposes of this paragraph, a “nonaqueous phase liquid” is a liquid that is not dissolved in water. Also include in the text for 1.2 Scope of work the possibility of the contractor to encounter free product at the former UST location and along the pipeline. Free product shall be removed in accordance with state regulations. |
Louis Howard |
| 8/22/1997 |
Update or Other Action |
SERA PL81 Inactive 10- inch pipeline
Review comments submitted for PL81 project. Clarification sought on what "contaminated" means beyond 2,000 ppm TPH. For example, GRO at 500 ppm or DRO at 1000 ppm. ADEC requests soil samples be taken for PID readings above 100 ppm and below 100 ppm to determine what exactly does 100 ppm equate to for DRO, GRO or RRO, or TPH. |
Louis Howard |
| 2/4/1998 |
Cleanup Level(s) Approved |
Comments on the Draft North Jet pipeline project. Cleanup level for the PL81 project for soil contamination encountered on the Air Force Property (north of the Port of Anchorage) will be 2,000 mg/kg DRO. Any contamination above that cleanup level will be dealt with at a later date when funding is available (e.g. year 2000, 2001). Any free product encountered will be recovered and disposed of properly. Excavation in the ROW on Port property will be limited to the removal of the pipeline and backfill with excavated soils. |
Louis Howard |
| 2/27/1998 |
Update or Other Action |
North Jet Pipelines Investigation Report received. During the spring of 1997, an investigation was conducted in the vicinity of the North Jet pipelines at the Elmendorf AFB/Port of Anchorage boundary. The investigation was designed to address data gaps identified in previous investigations. The findings of this investigation will be used to identify whether leakage has occurred from the North Jet Pipelines and to evaluate whether the contamination present has migrated beyond the EAFB/POA property boundary. Furthermore these findings will address whether contamination present in a tract of land adjacent to the Port of Anchorage on base which is being evaluated for potential lease to the Port. (Tract EE).
Based on the lmited soil collected, the predominent fuel contamination in soil is present at a depth immediately below where the fuel lines being investigated are believed to be buried. This strongly suggests the North Jet pipelines are the contaminant sources.
|
Louis Howard |
| 5/8/1998 |
Update or Other Action |
Fax received asking for concurrence to transport petroleum contaminated soils to ASR for treatment. Soil was generated during removal of the 10-inch pipeline. After review of the data, ADEC approved soils be sent to ASR for treatment on May 27, 1998. |
Louis Howard |
| 6/15/1998 |
Cleanup Level(s) Approved |
Letter to Larry Underbakke (AF) regarding the groundwater at Tract "A" and Tract "EE" (northern portion of PL81) being a non-potable source. 1994 ADEC (E. Olson) made the determination that at other facilities in the Port of Anchorage area, the shallow Port Area aquifer need not be considered an exposure pathway for human ingestion by drinking water. Therefore, the 5 ug/l benzene level does not apply for this project since the groundwater is not a drinking water source. 50 ug/L will be the final cleanup level.
The rationale for the determination for the shallow Port-Area aquifer is based on:
1) availability of the groundwater as a drinking water source, including depth to groundwater, and the probable yield of the aquifer;
2) actual or potential quality of the groundwater including organic and inorganic substances from background, saltwater intrusion (tidally influenced) and from the known or existing area-wide contamination in the Port of Anchorage Area;
3) the existence and enforceability of institutional controls by the landowner or comprehensive plans that prohibit or limit access to the groundwater for use as drinking water;
4) land use for the site and neighboring property (i.e. commercial or industrial);
5) an evaluation of the need for a drinking water source a the two properties and the availability of an alternative source (i.e. municipal water system at the Port);
6) whether the groundwater is exempt under 40 CFR 146.4.
Additionally, ADEC will require a point of compliance well (MW-POL-02) to be used to determine if POL migration occurs in the groundwater from MW-POL-01 to MW-POL-02.
Since the contaminated soils acting as a source near MW-POL-01 will be removed, residual contamination should decline over time. ADEC will require quarterly monitoring for one year and after reviewing the data may increase or decrease the monitoring frequency and locations. |
Louis Howard |
| 6/16/1998 |
Long Term Monitoring Established |
Long-term monitoring begun on a semi-annual basis with Fall 1998 sampling in conjunction with the Elmendorf Base-wide Groundwater monitoring program. |
Louis Howard |
| 6/17/1998 |
Update or Other Action |
10-inch pipeline removed, petroleum contaminated soil excavated. 196.4 tons taken from site to ASR for thermal remediation. Results from treatment show that levels are below Level "A" criteria. |
Louis Howard |
| 11/15/2000 |
Site Added to Database |
Former fuel pipelines fuel spills. |
Bruce Wanstall |
| 11/15/2000 |
Site Ranked Using the AHRM |
SERA PL81 Inactive 10-inch Pipeline
Preliminary ranking. |
Bruce Wanstall |
| 3/20/2001 |
Meeting or Teleconference Held |
Memo on PDBs being used as a "Beta Test" at Elmendorf AFB and Eielson AFB. The “Kick-off” meeting in Seattle, 20 March 2001, is intended to introduce the Remedial Process Optimization (RPO) process and the Passive Diffusion Bag Samplers (PDBS) guidance document “beta test” project at Elmendorf AFB and Eielson AFB, AK. The HQ Air Force Center for Environmental Excellence (AFCEE) is conducting an exhaustive “beta test” of the Guidance Document for Use of Polyethylene-Based Passive Diffusion Bag Samplers to Obtain Volatile Organic Compound Concentrations in Wells, described below, and provide feedback to the PDBS workgroup to update the Interagency PDBS Guidance Document for Installation Restoration Program (IRP) managers.
The RPO and PDBS guidance document “beta test” will incorporate remediation programs at Elmendorf AFB and Eielson AFB, AK. Passive diffusion bag (PDB) samplers are suitable for obtaining representative concentrations of volatile organic compounds in ground water in observation wells. A typical PDB sampler consists of a low-density polyethylene lay-flat tube closed at both ends and containing deionized water. The sampler is positioned at the target horizon by attachment to a weighted line. The PDB samplers equilibrate within approximately 48 hours for several tested volatile organic compounds, however vinyl chloride and some chloroethanes may require between 96 and 168 hours to equilibrate.
The samplers should be allowed to remain in the well a minimum of two weeks prior to recovery to allow the well water to restabilize following sampler deployment. Recovery consists of removing the samplers from the well and immediately transferring the enclosed water to 40-milliliter sampling vials for analysis. The method has both advantages and limitations. Advantages include the potential for PDB samplers to eliminate or substantially reduce the amount of purge water associated with sampling. The samplers are relatively inexpensive and easy to deploy and recover. Because PDB samplers are disposable, there is no downhole equipment to be decontaminated between wells and there is a minimum amount of field equipment required.
The samplers also have the potential to delineating contaminant stratification in the open or screened intervals of observation wells where vertical hydraulic gradients are not present. A possible disadvantage of the samplers is that they integrate concentrations over time. Depending on the compound of interest, this time may range between about 48 to 168 hours. The samplers are not applicable for all compounds. They are not effective for inorganic ions, for highly soluble organics such as methyl-tert¬-butyl ether, or poorly soluble organic compounds.
An additional disadvantage is water must be freely flowing through the well screen for the samplers to be effective. VOC concentrations in PDB samplers represent concentrations in the vicinity of the sampler within the well screen or open interval. This may be a limitation if the ground-water contamination is above or below the screen, or not in the interrogated sample intervals. If there are vertical hydraulic gradient in the well, then the concentrations in the sampler represent the concentrations in the water flowing vertically past the sampler rather than in the formation immediately adjacent to the sampler. Multiple PDB samplers may be needed in chemically stratified wells or where flow patterns through the screen change as a result of ground-water pumping or seasonal fluctuations. |
Louis Howard |
| 6/29/2001 |
Update or Other Action |
SERA PL81 Inactive 10-inch Pipeline
No further remedial action required status for the northern portion of PL81 since PL-MW-01 and PL-MW-02 are below the 50 ug/L level and actually PL-MW-02 is below the 5 ug/L drinking water level but PL-MW-01 is at 15 ug/L.
PL81 is located, in part, in the Port of Anchorage area as well as on Elmendorf Air Force Base. ADEC did require the Air Force monitor a point of compliance well (MW-POL-02) to determine if POL migration occurs in the groundwater from MW-POL-01 to MW-POL-02. Since the contaminated soils at the northern portion of PL81 were removed and properly remediated and are not acting as a continuing source, residual groundwater contamination has shown a marked decline over time (1998-2000). PL-MW-02 has actually shown to be below the drinking water criteria of 5 ug/L during the sampling in 2000. PL-MW-01 has never been above the 50 ug/L cleanup criteria for benzene. Therefore, based a review of the data ADEC will grant this site a “no further remedial action required” determination for that portion located in the northern Port area on Elmendorf property.
However, if in the future, additional contamination is discovered at this particular site, further investigation and/or remedial actions will be requested of the Air Force by ADEC. ADEC reserves its rights, under 18 AAC 75 Oil and Other Hazardous Substances Pollution Control regulations and AS 46.03 to require the Air Force to conduct additional assessment and/or corrective actions, if information indicates the site conditions pose an unacceptable risk to human health, safety, or welfare, or to the environment.
To achieve a “site closed” approval by ADEC, the Air Force must show that benzene levels in the groundwater are below 5 ug/L at both wells (PL-MW-01 and PL-MW-02) for two consecutive years. |
Louis Howard |
| 6/3/2002 |
Update or Other Action |
Basewide Environmental Monitoring Plan received.
Up to five new monitoring wells will be installed during the 2002 field season. The specific
location for these monitoring wells will be determined using both historical data and data results from the soil gas survey. One to two wells will likely be placed downgradient of the TCE plume associated with Well 403-MW-01. Two additional wells will likely be placed downgradient of the Dallas Housing Project, and a final well placed downgradient of WP14 as a replacement well for OU6MW-13 which is believed to be screened in the incorrect aquifer.
Groundwater samples will be collected biannually from 13 wells and annually from one well as
part of the OU 6 Basewide Program (Table 2-1). In addition, eight seep locations will be investigated and sampled during the 2002 Basewide Program.
Six wells will be dropped from OU 6 for 2002. Each well was dropped because it either provided
redundant information, or was screened or placed in an ineffective location and offered no relevant data. Wells dropped were 14-MW-133, K301, K302, OU6MW-06, OU6MW-13 and OU6MW-70. One well, OU6MW-91, was added to OU 6 in 2002 to aid in tracking the benzene plume associated with WP 14 and PL81.
Three analytical methods will be added to the sampling scheme for OU 6 in 2002. Anions
(chloride and sulfate), TOC, and dissolved gases will be added to help track natural attenuation in OU 6 and its associated source areas. DRO and GRO will remain in the analytical suite for wells on the bluff associated with LF04 and WP14.
In order to more accurately predict deviation of natural attenuation of solvents, groundwater
modeling should be performed for the WP 14/PL81 plume. |
Louis Howard |
| 10/21/2002 |
Update or Other Action |
J. Roberts sent a letter to Joe Williamson dissolving the State Elmendorf Environmental Restoration Agreement. The Alaska Department of Environmental Conservation (DEC) has reviewed the issue of abolishing the State Elmendorf Environmental Restoration Agreement (SERA) per your recommendation. Elmendorf Air Force Base and DEC entered into the SERA in 1992. The agreement was developed as a tool to bring the Base into compliance with Alaska's regulations addressing underground storage tanks, oil and other hazardous substance releases and solid waste.
Since that time, Elmendorf has made significant progress in investigating and cleaning up historic contamination problems. Many of the sites covered by the SERA have been successfully cleaned up and closed. Cleanup is underway at the remaining sites.
Additionally, Alaska has amended the regulations addressing fuel storage tanks, oil and other hazardous substance spills and solid waste. We concur with you that the SERA is no longer a necessary or beneficial. This letter serves as notice that DEC will end oversight on environmental work at Elmendorf by using the SERA. Instead, it is understood that the sites and programs formerly addressed by SERA: solid waste, underground storage tanks (UST), and oil and other hazardous substance discharges will be addressed in accordance with 18 AAC 60, 18 AAC 78 and 18 AAC 75. |
Jennifer Roberts |
| 3/28/2003 |
Update or Other Action |
2002 ANNUAL REPORT BASEWIDE ENVIRONMENTAL MONITORING PROGRAM received. This plume is located on the western portion of EAFB above the Knik Arm Bluff near the intersection of 26th Street & the Knik Bluff Trail. The PL81 North Plume trends northeast to southwest. The lateral extent of the plume has not been defined. The known extent is up to 800’ in length, with a width of approximately 400’.
Although several documented source areas exist in the vicinity of the PL81 North Plume, including WP14 & LF04, the source for the PL81 North Plume was determined to be Valve Pit 11. This valve pit is part of an abandoned pipeline designated PL81 under the SERA program. The dissolved contaminants released from this valve pit have been shown in previous investigations to have migrated westward to areas WP14 & LF04. At depth, the plume occupies a shallow unconfined aquifer on the southern margin of the Elmendorf Moraine physiographic unit. The following subsections describe the physical characteristics & GW quality in this region of OU 6.
Seep LF04-SP04 appears to be the point where the PL81 North Plume discharges. The origin of the seep is at an elevation of 145.61’ above msl, which correlates well with the westward end of the shallow aquifer. Contamination found in this seep is not unexpected based on upgradient GW conditions in this aquifer. However, Seep LF04-SP03, its origin found at an elevation of 106.66’ above msl, is likely the daylighting point of a deeper aquifer. This elevation appears to correlate with deep GW encountered during drilling of OU6MW-13 & OU6MW-77. Benzene was found at 9.1 ug/L in the sample from this seep. It is unclear whether the benzene detected in LF04-SP03 represents actual aquifer contamination or if the source is located on the bluff slope. It is possible that contaminants are migrating downward through slope deposits & impacting the downgradient portion of this aquifer. It is known that GW in OU6MW-13 is uncontaminated & has been so in all sampling events. GW results from OU6MW-77 cannot be correlated to Seep LF04-SP03 because the well was completed & screened in the shallowest aquifer.
Due to the highly fluctuating levels of fuel compounds & a limited data set for many wells in this plume, statistical analysis was not performed for all locations. However, a time-series plot & statistical analysis were performed for the downgradient Well OU6MW-77. The time-series plot, shown on Figure 3-11, displays large fluctuations in benzene levels.
An assessment of natural attenuation parameters for the PL81 North Plume shows excellent evidence for biodegradation of fuels. Microbes are rapidly utilizing all available electron acceptors throughout the plume, indicating the presence of several species of microorganism. In addition, alkalinity appears to be at elevated concentrations in some downgradient portions of the plume, which is also an indication of strong microbial activity.
Although microbial degradation of fuel compounds is highly active in this plume, a review of historical & current data suggests the presence of a residual source. Based on previous investigations, however, this is not unexpected. Both the 1994 RI/FS & the 2000 site evaluation found evidence of smear zone contamination in as many as 23 soil borings. Evidence for smear zone contamination was also reported during the 2001 & 2002 investigations. Data for wells throughout the plume display fluctuating levels, as would be expected in wells affected by seasonal rise & fall of GW elevations in the presence of smear zone contamination. The historical & current presence of free product in wells within this plume is likely a residual source for much of the smear zone contamination found. In addition, vadose zone soil contamination was reported during the 2000 investigation in SB 122, SB 132, SB 133, & SB 134 installed next to the valve pit & SB 121 installed in the weathering pad area in WP14. The recommendation after the investigation was to remove up to 400 cubic yards of contaminated soil from the vadose zone.
Evidence for natural attenuation within this plume is very strong. Vadose zone & smear zone soil contamination continue to impact GW. It is expected that this residual soil contamination will remain as a source for GW contamination for many years. It is therefore recommended that contaminated vadose zone soil be excavated from the subsurface. In addition, it is recommended that free product be removed using a passive system if feasible. The use of free product removal systems may be limited due to overcompacted soils & a generally low yielding aquifer. An addition of one to two more wells downgradient of OU6MW-91 & OU6MW-94 is recommended to characterize the westward extent of free product & the shape of the shallowest aquifer. |
Louis Howard |
| 10/1/2003 |
Update or Other Action |
The Basewide Groundwater Monitoring Plan received. The BW GW Monitoring Program (herein called "the Program") was established through the Elmendorf Air Force Base (herein "the Base") Installation Restoration Program to address the needs of multiple programs on the Base. These programs include the Federal Facilities Agreement (FFA) and the State-Elmendorf Environmental Restoration Agreement (formerly "SERA"; now known as "State Program Sites".)
In response to the findings of the Records of Decisions (RODs) for each program area, the United States Air Force began annual groundwater monitoring. This Basewide Groundwater Monitoring Plan ("the Plan") presents relevant historical direction and methodologies of the Program in addition to background information on individual program areas. A generalized approach to groundwater monitoring practices for the Program is also provided in this Plan. A yearly Program Activities Addenda, detailing specific activities to be performed, will be submitted annually.
PL81 North-This plume is a State Program Site located on the western portion of Elmendorf AFB above the Knik Arm Bluff near the intersection of 26 th Street and the Knik Bluff Trail. The PL81 North Plume is oriented northeast to southwest. The lateral extent of the plume has not been defined. The known extent is up to 800 feet in length, with a width of approximately 400 feet.
Although several documented program areas exist in the vicinity of the PL81 North Plume, including WP14 and LF04, the primary source for the PL81 North Plume was determined to be Valve Pit 11. This valve pit is part of an abandoned pipeline designated PL81. The dissolved contaminants released from this valve pit have been shown in previous investigations to have migrated westward to areas WP14 and LF04. At depth, the plume occupies a shallow unconfined aquifer on the southern margin of the Elmendorf Moraine physiographic unit. The PL81 North Plume received the highest score of the Elmendorf AFB groundwater plumes during rankings. Subsequently, this plume will receive the most detailed description. The following subsections describe the physical characteristics, groundwater quality and state of compliance for PL81 North.
Although microbial degradation of fuel compounds is highly active in this plume, a review of historical and current data suggests the presence of a residual source. Based on previous investigations, however, this is not unexpected. Both the 1994 Remedial Investigation/Feasibility Study (RI/FS) and the 2000 site evaluation found evidence of smear zone contamination in as many as 23 soil borings. Evidence for smear zone contamination was also reported during the 2001 and 2002 investigations. Data for wells throughout the plume display fluctuating concentrations, as would be expected in wells affected by seasonal rise and fall of groundwater elevations in the presence of smear zone contamination. The historical and current presence of free product in wells within this plume is likely a residual source for much of the smear zone contamination found.
Decision documents established a cleanup goal of 14 years (2011) for groundwater. Given that contaminated vadose zone and smear zone soils are present at the site, along with free product on the water table, it is unlikely that this goal will be met. Hence, future remedial activities at PL81 North should focus on further delineating this plume and enhancing the level of natural attenuation sampling to assess progress towards cleanup levels specified in the decision documents. Additional evaluation of the free product present should be performed to determine whether the product present would naturally attenuate over time by the specified cleanup date. However, free product recovery should continue to be performed by hand bailing wells during sampling events.
PL81 South is a State Program Site located in the northwest portion of the Elmendorf cantonment area on the bluff overlooking Knik Ann. Ground surface slopes slightly to the west and surface drainage occurs in the general direction of Knik Ann. The surface of the site has been altered by construction activities and is currently covered by low alder growth. As is the case at PL81 North, WP14 is the suspected source of contamination at this site. Conditions at this plume are similar to PL81 North due to their proximity. Future remedial activities at PL81 South should focus on plume delineation and monitoring natural attenuation as specified in the ROD. Free product recovery should be performed by hand bailing wells during sampling events. Seep sampling should continue on the bluff above Knik Arm. |
Louis Howard |
| 2/3/2005 |
Meeting or Teleconference Held |
Elmendorf FFA XIII. REPORTING 13.1 USAF shall submit to the other Parties quarterly written progress reports. The reports will include, but not be limited to, the following information:
(a) A detailed summary of all of the remedial, removal, and investigation activities during the previous quarter, including any analytical results, any community relations activities, and any community contacts or inquiries related to the hazardous substance contamination at the Site; (b) An outline of the planned activities for the upcoming quarter;(c) A detailed statement of the manner and the extent to which the timetables and deadlines are being met;(d) The status of efforts to obtain rights-of-entry necessary for monitoring and well installation off base; and(e) The status of any other activities proposed or underway that may affect any phase of the activities described in the Attachments.
13.2 The quarterly written progress reports shall be submitted on the tenth (10th) day of each calendar quarter following the effective date of this Agreement.
Meeting minutes from RPM meeting February 3, 2005, ADEC and EPA agreed to decrease the frequency of quarterly reports to semi-annual or twice a year. Quarterly Progress Reports (QPRs) (USAF). EPA and ADEC confirmed that the information they receive in the report, in its current format, is quite useful to them when they are briefing their higher headquarters. Both agreed that we could reduce submittals to semi-annual reports, which will be submitted in December and May of every year. ADEC requested that we continue to break sites out by Operable Unit since that is the way their database has been designed to track.
PL81, Status of Performance-Based Contract and Decision Document (Ms. Godden). The contractor produced the decision document within 2 months of contract award. It took 6 weeks to get the wing commander's signature. The HQ PACAF review took almost 5 weeks. We had allowed 6 months from receipt of draft final to signatures. Based on the rate of progress, we should have allowed more time. Additionally, the contract milestones did not provide for any payment to the contractor until the decision document is signed. In retrospect, we should have made some provision for payment upon receipt of the draft final.
The decision document has been at Air Staff for 3 weeks; they have 4 weeks to provide comments. Mr. Williamson stated that the contractor will probably take a loss on the contract and that contracts should be much larger (around $30 million) for them to be profitable to the contractor. EPA asked if there is still a push from Air Staff to have a minimum percentage of our contract designated as performance based. Mr. Williamson affirmed and stated that it appeared that some types of projects would not be good candidates. He suggested that the DP98 hot spot removal might have been a good choice; GW probably is not a good choice. |
Louis Howard |
| 3/4/2005 |
Update or Other Action |
Mar 05 4 Elmendorf Air Force Base PL81 Valve Pit Soil Cleanup Decision Document 04-WERC13SWF received. The document describes the selected remedial action for Site PL81-Valve Pit 11 (PL81) Soil Cleanup at Elmendorf Air Force Base (AFB), north of
Anchorage, Alaska (Figure 1). Site PL81 is located on the western edge of the Base as shown on Figure 2. Site PL81 is the site of a fuel spill related to operation of the former fuel pipelines.
The remedy targets petroleum-contaminated soil in the vadose zone at Valve Pit 11. Groundwater cleanup is underway pursuant to the Operable Unit (OU) 6 Record of Decision (ROD). The current land use designation is open space and no known historic buildings, archeological sites, wetlands, floodplains, or rare or endangered species are located at PL81. Anticipated future land use is also open space, as reflected in the Base General Plan.
Alternative PL81-3: Excavation and Disposal. This alternative was
selected as the preferred remedy because it would provide the greatest level of effectiveness that is technically and economically feasible. Additionally, this alternative will accelerate the cleanup of groundwater contamination.
Selected Remedy - Excavation of petroleum-contaminated soil in the vadose zone below Valve Pit 11 and disposal at a local treatment facility.
The selected remedial action approach will include the following tasks:
• Excavation of clean overburden soil and underlying petroleum-impacted soil with confirmed concentrations exceeding the OU-6 cleanup levels. Soil will be segregated on site on plastic to separate clean overburden soil from petroleum-impacted soil with concentrations exceeding cleanup levels. The remedial action approach will include provisions for transporting impacted soil as a covered load in compliance with Title 18 of the Alaska Administrative Code, Chapter 60.015. The soil will also be stored in compliance with Title 18 of the Alaska Administrative Code, Chapter 75.370.
• Confirmation of impacted soil removal will be verified vertically by
excavation to the water table, and horizontally by collection and analysis of sidewall confirmation soil samples.
• Disposal of impacted soil at a local treatment facility equipped and
certified to accept, treat, and dispose of the soil.
• Backfilling and compaction of the excavation with segregated clean overburden soil and imported clean soil.
• Decommissioning of monitoring well 14MW133 per the ADEC regulations, and protection of monitoring wells 14MW120 and OU6MW60 during remedial activities.
• Restoration of the site.
• Preparation of a final report of all remedial activities with
recommendations for a NFRAP determination by the ADEC.
Soil contaminants of concern-Gasoline range organics: 1,100 to 2,200 mg/kg (cleanup-500 mg/kg), diesel range organics: 2,100 to 4,900 mg/kg (cleanup 1,000 mg/kg), benzene: 1.8 to 3.9 mg/kg (cleanup 0.5 mg/kg) and total BTEX: 74.6 mg/kg (cleanup 50 mg/kg) taken from the OU6 Record of Decision. The remedial action objective for PL81 is cleanup of vadose zone soil to chemical-specific cleanup levels in Table 1 to prevent contamination migration to groundwater.
Remedial activities for PL81 do not include the restoration of groundwater beneath the site. The groundwater beneath PL81-Valve Pit 11 is being addressed under the Elmendorf OU6 Record of Decision. Therefore land use controls (LUCs) for groundwater are not applicable as a part of the selected remedy. |
Louis Howard |
| 3/31/2005 |
Update or Other Action |
2004 Phase I RPO (remedial process optimization) Annual Report received for GW performance optimization monitoring program. PL81 South Plume is located in the southern portion of site LF04 in the west-central part of EAFB approximately 600 feet southwest of the WP14/PL81 North & OU6MW-46 plumes. This plume is approximately 250 feet long, trending east-west, & discharges to the bluff at Seep LF04SP-02. The site is located on outwash plain soils, with GW found at approximately 45 feet below ground surface (bgs).
In addition to monitoring COC levels, floating product measurements were taken from various wells in the vicinity of the PL81 South Plume in 2004. Floating product measurements were to be collected from wells OU6MW-63, OU6MW-74, K303, & K304 in addition to seep LF04SP-02DG. During well inventory efforts, it was discovered that OU6MW-74 & K304 no longer exist. Instead, product thickness measurements were collected from OU6MW-63, OU6MW-61, OU6MW-13, OU6MW-46, OU6MW-94, K303, & seep LF04SP-02DG during Round 1 & Round 2 monitoring events.
The reason for collecting these product measurements was to determine whether floating product was present, & if so, to recommend the most efficient means of collecting it. However, no floating product was encountered during the Round 1 or Round 2 monitoring events at any of the wells or at the seep inspected. Although floating product has been historically encountered in the past, none was encountered in 2004.
A pump house west of well OU6MW-63 had been part of an abandoned pipeline & has been identified as the source of this plume. The pump house has been designated PL81. Previous investigations determined that dissolved contaminants were released from the source & migrated westward toward Knik Arm. Monitoring is performed at one GW well, OU6MW-63, & three seeps.
Remedial activities at the PL81 South Plume will continue. There is no predicted cleanup date for this plume. The three GW COCs (benzene, DRO, & GRO) remain above their respective cleanup levels of 5 µg/L, 1,500 µg/L, & 1,300 µg/L, respectively. Only levels of the 3 surface water COCs (benzene, total aromatic hydrocarbon [TAH], & total aqueous hydrocarbon [TAqH]) at seep LF04SP-02 remain above regulatory levels. Monitoring activities will continue at the PL81 South Plume & will be structured to monitor benzene, DRO, & GRO in GW & benzene, TAH, & TAqH in surface water.
To improve the current techniques used for performance monitoring at this plume, the following items are recommended:
COC monitoring for this plume is performed at one well & three seeps. It is recommended that monitoring network optimization & sampling frequencies continue to be determined by using the decision guides in Appendix H.
Free product measurements were collected from several wells & one seep in the vicinity of this plume during both sampling rounds in 2004. Although free product has been observed historically in this vicinity, none was encountered in 2004. The absence of free product could be attributed to natural attenuation or the low GW levels encountered during the dry year of 2004.
Regardless, it is recommended that no product collection devices be used in this area for the simple reason that no free product was encountered. It is also recommended that product levels in the six wells & one seep be measured during the 2005 Round 1 sampling event to determine whether free product returns with higher GW elevations. Free product recovery efforts should continue to be performed when product in excess of 0.1 foot is encountered during sampling events. Although this situation has not occurred for several years, the requirement to collect product when it is thicker than 0.1 foot should remain.
Contaminant mass calculations cannot be determined at this plume with any high degree of accuracy. The PL81 South Plume is a one-well plume. It is recommended that contaminant mass calculations not be performed at the PL81 South Plume.
It is recommended that MNA monitoring at the PL81 South Plume be discontinued. MNA assessments cannot be accurately performed at one-well plumes.
The PL81 South Plume is a State Program Site. However, the decision documents for these state programs do not set a date by which remedial cleanup levels are to be met. It is recommended that a cleanup date for the PL81 South Plume be calculated by using SourceDK Tier 1. Although Tier 1 does not establish milestones to be used as a performance check, these milestones may be established manually once a cleanup date has been predicted.
MNA & free product recovery is the selected remedy at the PL81 South Plume. This remedy should not be considered protective of human health & the environment. Although COC levels in well OU6MW-63 are decreasing, plume expansion seems to be occurring in that elevated benzene concentrations are daylighting at seep LF04SP-02. |
Louis Howard |
| 5/13/2005 |
Update or Other Action |
WORK PLAN PL81 VALVE PIT 11 SOIL CLEANUP received. PL81 is
the site of Valve Pit 11 and the location of a historic fuel release composed of Jet Fuel-Grade 4 (JP-4) and aviation gasoline (AVGAS) that contaminated vadose-zone soil to depths of
approximately 18 feet below ground surface (bgs). Groundwater beneath PL81 has also been impacted, however, remedial activities addressed by this work plan do not include the restoration of groundwater beneath the site.
The presence of contamination in the vadose zone soil creates
the potential for further degradation of groundwater. The project schedule for preparation, excavation, and closure extends for approximately one year, from final approval of the Decision Document and Work Plan planned for late Apr 05, through completion of remediation in Jun 05, to receipt of a No Further Remedial Action Planned (NFRAP) letter from the Alaska Department of Environmental Conservation (ADEC) anticipated in Sep 05. The PL81 remedy includes the excavation and off-site treatment and disposal of impacted soil and the backfilling of the excavation with clean over-burden and imported soil.
Following excavation, confirmation samples will be collected along the sidewalls of the excavation to confirm adequate removal of soil with concentrations exceeding cleanup levels. Sidewall samples will be collected using the decontaminated excavator bucket from the vertical midpoint of the excavation sidewall. A minimum of six inches of soil will be scraped from the sidewall immediately prior to sample collection.
Confirmation soil samples will be submitted to an off-site laboratory and analyzed for GRO by Alaska Method AK101, DRO by Alaska Method AK102, and benzene and total BTEX by EPA Method 8260B. The samples will be analyzed on a 24-hour turn-around time (TAT) basis. Confirmation samples will be validated and reported in the remedial action completion report and closure documentation of PL81.
Stockpile samples will be collected as soil is excavated for placement in the clean overburden stockpile to confirm that the soil does not contain COCs at concentrations exceeding cleanup
levels so that the soil can be used for backfilling the excavation. A total of five (5) stockpile samples are estimated based on a 10% laboratory confirmation of field screening samples. The total number of laboratory-analyzed samples equates to one sample per 100 cubic yards of stockpile and a total stockpile volume of 500 cubic yards.
Following completion of excavation activities, soil in the clean overburden stockpile will be used for excavation backfilling. Prior to use as backfill, confirmation sample results will be used to
confirm that the soil does not contain contaminants at concentrations exceeding cleanup levels. Soil in the contaminated stockpile will be loaded on trucks and will be transported to Alaska Soil Recycling for thermal treatment and off-site disposal. Waste characterization sampling is not required for treatment and disposal by the treatment facility. Historical soil data from the 2002
base-wide environmental monitoring program (USAF 2003a) will be provided to the treatment facility for waste characterization purposes. |
Louis Howard |
| 5/23/2005 |
Cleanup Plan Approved |
Decision document for PL81-Valve Pit 11 Soil cleanup approved. The remedy targets petroleum contaminated soil in the vadose zone at Valve Pit 11. The groundwater is beneath PL81 is addressed under CERCLA due to its connection with two other CERCLA sites *(WP14 and LF04 Operable Unit 6). Excavation and disposal at a local treatment facility was selected as the preferred remedy because it would provide the greatest level of effectiveness that is technically and economically feasible. Additionally, this alternative will accelerate the cleanup of groundwater contamination. |
Louis Howard |
| 5/23/2005 |
GIS Position Updated |
Report states the Global Positioning System (GPS) coordinates are 6793997.2 meters north and 345901.25 meters east. |
Louis Howard |
| 5/23/2005 |
Institutional Control Record Established |
Institutional Controls established and entered into the database. |
Louis Howard |
| 6/1/2005 |
Update or Other Action |
Staff received and reviewed a request for treatment of excavated soil from the PL81 Valve Pit 11 project. Staff concurred with the request to transport petroleum contaminated soil from the site to Alaska Soil Recycling. |
Louis Howard |
| 9/19/2005 |
Update or Other Action |
Remedial Action Report received. It included the excavation, transportation, and off-site treatment and disposal of impacted vadose zone soil, and the backfilling of the excavation with clean overburden and imported soil as approved in the Decision Document, PL81-Valve Pit 11 Soil Cleanup, Elmendorf Air Force Base, Alaska (USAF, 2004). All work was conducted in accordance with the Final PL81-Valve Pit 11 Soil Cleanup Work Plan (USAF, 2005).
Stockpiled contaminated soil was later transported for off-site treatment and disposal at the Alaska Soil Recycling facility in Anchorage, Alaska. The excavation extend vertically to the base of the vadose zone and horizontally until field screening indicated that petroleum-contaminated soil had been removed. A total of 883 cubic yards of
contaminated soil were excavated and transported for off-site treatment of disposal.
Post excavation soil samples were obtained from both the excavated clean overburden soil and the sidewalls of the excavation, in accordance with the Field Sampling Plan (FSP). Upon receipt of analytical results confirming that all contaminated soil had been removed and the clean overburden soil was appropriate to use as backfill material, the excavation was backfilled and the Site was restored.
The vadose zone soil removal activities defined in the PL81 Decision Document (USAF, 2004) have been completed. The results of the post excavation soil sampling and analysis indicate contaminated vadose zone soil exceeding PL81 soil cleanup levels were excavated. |
Louis Howard |
| 9/22/2005 |
Cleanup Complete Determination Issued |
Based on the data and information provided, ADEC agrees with the Air Force's request that vadose zone soil remedial actions are complete and that no further action is necessary for vadose zone soil at this site.
ADEC reserves all of its rights, under AS. 46.03, 18 AAC 75, and 18 AAC 78 to require the Air Force to conduct additional site assessment, monitoring, remediation, and/or other necessary actions at PL81-Valve Pit 11, if information becomes available that contamination is found at this site, which poses a threat to human health or safety, welfare, or the environment.
Although PL81 Valve Pit 11 was not formally identified as a site until after the OU6 ROD was
signed, the 2005 PL81 Decision Document states that all groundwater contamination attributable to PL81 will be managed by the OU6 ROD. Therefore, groundwater contamination associated with PL81 is monitored as part of the LF04 South and WP14 groundwater monitoring program.
Groundwater will be monitored as part of OU6 and the site known as PL81 will be administratively closed out and future groundwater monitoring will be associated with OU6 source areas LF04 and WP14. |
Louis Howard |
| 2/1/2006 |
Update or Other Action |
PL81 South Limited Field Investigation Report received. The report outlines the limited subsurface investigation and dye tracer study at the site. Dye was added to OU6 monitoring well 63 (OU6MW-63) and seeps were monitored. Six soil borings were continuously logged during advancement of the boreholes. BH-04, BH-05, BH-06 met refusal before encountering groundwater at depths of 20, 30, and 20 ft. bgs, respectively.
The limited soil investigation provided data to indicate that contamination from the former
pump house has percolated down to a low permeability layer at approximately 20 feet bgs.
In some areas, the low permeability layer acted as a barrier causing contamination to
accumulate on top. In these areas, soils above the barrier are currently contaminated and
moist. The soil below the barrier, in these areas, is uncontaminated. In other areas, fuel
could pass through the low permeability area though seemingly preferential pathways as
evident by fuel stained streaks.
Maximum concentrations in soil: Total BTEX-204 mg/kg, benzene 1.7 mg/kg, ethylbenzene 28 mg/kg, total xylenes 131 mg/kg, toluene 45 mg/kg. GRO BH-10 had the highest GRO levels at 22' bgs (2,300 mg/kg) and at 39' (2,100 mg/kg). BH03 had the highest DRO levels at 20.25' bgs (2,600 mg/kg) and 10' bgs (2,500 mg/kg).
Fluorometry readings started before the dye was added as a background reading on July 22, 2005. Last two readings on 11/18/05 (120 days after dye injection) at Seep 02-07 and on 12/6/05 (138 days after dye injection) at Seep 02-08 showed fluorescence measurable at 0.07 and 0.06 respectively.
The detectable dye measured with the fluorometer in the seep samples provides evidence that the groundwater beneath PL81 South is in hydraulic communication with the seep down gradient of the site. The portion of the aquifer beneath PL81 site flows towards the west (towards Knik Arm) and appears to discharge at the down gradient seep.
As mentioned previously, dye was visually apparent in the groundwater sample collected
from OU6MW-63 on 6 December 2006 and was present at a significantly higher
concentration in the monitoring well than in the seep sample collected on the same day.
Therefore, the highest dye concentrations are present between the well and the seep, and
concentrations in the seep will continue to rise over time. Further monitoring in the months of
January and February, may provide additional qualitative data on groundwater flow beneath
the site. Because only the leading edge of the dye plume was reaching the seep 120 days
after injection, actual seepage velocities at the site are slower than previously estimated.
Visual observations of surface water flowing from the seep indicate that flow rates are highly variable. During each seep sampling event, at least a minimal amount of water was discharging (base flow). However, during some sampling events, particularly following periods of high precipitation, flow rates were far greater. This bimodal distribution of flows indicates that base flow takes place in relatively low conductivity zones and that higher groundwater levels allow flow through higher conductivity zones. As groundwater levels rise, a steeper gradient toward the seep is created driving greater flow rates through zones of high conductivity. Thus, groundwater flow rate vary significantly with groundwater levels.
Biodegradation of fuel contaminants is apparent at the seep by significant iron staining and biogenic sheen. |
Louis Howard |
| 5/1/2006 |
Update or Other Action |
The 2005 Remedial Process Optimization Report received in May 2006. Sites LF04, PL81, and WP14 have plumes that appear to be commingling; therefore, the sections discussing these three sites have been kept together in this report. The groundwater plumes at these three sites are addressed under the requirements specified in the OU 6 ROD. According to the 2005 PL081 Decision Document, groundwater beneath Site PL81 is addressed under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) due to its hydraulic connection with sites LF04 and PL81, which are both addressed in the OU 6 ROD. Two plumes, OU6MW-46 and PL81 South, comprise Site PL81. Two groundwater monitoring wells and three seeps are associated with this site. Each well is configured to monitor one plume. In-source well OU6MW-46 monitors the OU6MW-46 Plume, and in-source well OU6MW-63 monitors the PL81 South Plume. The three seeps associated with the PL81 South Plume are LF04SP-01, LF04SP-02, LF04SP-02DG.
FYI: 2018 SI report for AFFF Sources on JBER-E/JBER-R detected exceedances of PFOS in LF04SP-02 above applicable cleanup levels. |
Louis Howard |
| 4/17/2007 |
Update or Other Action |
2006 Annual Phase I RPO report (Draft) received. GW is addressed under OU6 WP14 and LF04.
See site file for additional information. |
Louis Howard |
| 5/14/2007 |
Update or Other Action |
Draft 2006 Zone 1 Annual Remedial Process Optimization Report, April 2007 received on April 18, 2007. Based on the data presented in the report and any pending U.S. EPA comments, ADEC will approve the document as submitted. |
Louis Howard |
| 11/20/2007 |
Update or Other Action |
2007 Zone 1 Remedial Process Optimization (RPO) Report received for contaminated sites and associated underlying groundwater for the western portion of EAFB. This area, referred to as Zone 1, includes: DP98, ST36/66, ST41, ST61, ST69, LF04 North, PL81, WP14, and LF02. Site PL81 is located in the westcentral part of EAFB. PL81 is the former location of an abandoned 10-inch pipeline that extended from the Port of Anchorage to Valve Pit 14 on EAFB. The pipeline was abandoned in 1964 after the Good Friday earthquake and removed in 1997. Remedial investigation studies for OU6, which includes the PL81 area, revealed petroleum, oil, and lubricants (POL) contamination from this pipeline. Two plumes (OU6MW-46 and PL81 South) comprise Site PL81.
Although this site was not formally identified as a site until after the OU6 ROD was signed, the PL81 area is within the groundwater contamination area addressed by the OU6 ROD. In addition, the two plumes at Site PL81 have the potential to commingle with LF04 groundwater, which is addressed in the OU6 ROD; therefore, groundwater at Site PL81 is addressed under the OU6 ROD. Presently, performance-monitoring samples are collected from three groundwater monitoring wells and one seep, which emerges on the face of the bluff overlooking Knik Arm.
See site file for additional information. Monitoring of groundwater will be associated with OU6 Source areas WP014 and LF004. |
Louis Howard |
| 2/25/2010 |
Update or Other Action |
2009 Zone 1 Field Activities Report received. Zone 1 is one of three zones established on EAFB for management of environmental restoration. Sites managed under Zone 1: LF02, LF04, WP14, ST36/66, ST41, ST61, ST69, & DP98. GW contamination is monitored at 10 plumes in Zone 1, & exposed landfill debris is removed annually at LF04. Five sites (LF02, LF04, WP14, ST41, & DP98) are administered under CERCLA with U.S. Environmental Protection Agency (EPA) oversight & are governed by Records of Decision (ROD). The 3 remaining sites (ST36/66, ST61, & ST69) are regulated according to State of AK cleanup requirements.
LF04 South encompasses the southern portion of LF04, west of the WP14 source area. The OU6 ROD (USAF 1997) refers to GW in this area as bluff GW & seep GW. Fuel-related contaminants & VOCs present in the GW are attributed to past waste management practices such as the landfill, leaking petroleum, oil, & lubricants (POL) facilities such as the PL81 pipeline, & migration from WP14, an upgradient source.
WP14- Petroleum hydrocarbon contamination originated during 1964 to 1968, when the area was used for fuel-tank sludge disposal generated from POL tank cleanout operations & for weathering fuel filters & pads on the ground surface. Fuel contamination may also be associated with a former pipeline upgradient of WP14 (e.g. PL81).
PL81 is the former location of an abandoned 10-inch pipeline that extended from the Port of Anchorage to Valve Pit 14 on EAFB. The pipeline was abandoned in 1964 after the Good Friday earthquake & removed in 1997. Although PL81 was not formally identified as a site until after the OU6 ROD was signed, the PL81 DD states that all GW contamination attributable to PL81 will be managed by the OU6 ROD. Therefore, GW contamination associated with PL81 is monitored as part of the LF04 South & WP14 GW monitoring program.
See site file for additional information. GW monitoring will be associated with OU5 Source areas LF004 and WP014 for PL81. |
Louis Howard |
| 4/4/2016 |
Institutional Control Update |
Land Use Control Inspection Report At State-Regulated Sites With ‘Cleanup Complete - Institutional Control’ Status Joint Base Elmendorf-Richardson, Alaska received.
Site PL081 was inspected on 22 October 2015. No deficiencies were noted |
Louis Howard |
| 9/16/2016 |
Update or Other Action |
Supplemental WP received to address the groundwater sampling, institutional controls (IC) inspection, and landfill cap inspection activities associated with the 2016 Long Term Monitoring (LTM) at the Joint Base Elmendorf-Richardson (JBER), Sites PL081, CG551, ST408, CG530, SO510, SS522, SO507, SS418, TS003, CG543, CG529, TU107, ST048, CG509, SO508, SO549, AT035, AT029, SS019, and DP009.
As a requirement of the 2016 Environmental Long Term Monitoring contract, the following work shall be performed at JBER Site PL081:
- Perform IC inspection
- Complete site closure document
See site file for additional information. |
Louis Howard |
| 10/4/2016 |
Document, Report, or Work plan Review - other |
Staff provided comments on the draft supplemental work plan.
Main comment was to ensure that work was not proceeding without a DEC approved work plan. Schedules in the document stated that work was to be conducted in September 2016. Other comments were regarding the appropriateness of drafting a closure document for PL081 when there is demonstrated exceedances of TAH/TAqH and soil cleanup levels at the source area. Clarification was requested on whether or not EPA has formally accepted ADEC and the Air Force's decision to address soil, groundwater contamination into OU6 and accept cleanup levels in the OU6 Record of Decision as PL081's cleanup levels. Finally, comments were made regarding the sampling frequency for surface seeps on an annual basis when other seeps on JBER-E have exceedances and are sampled on a quarterly basis as agreed to by the Monitoring Frequency Guide for JBER-Elmendorf.
See site file for additional information. |
Louis Howard |
| 3/22/2017 |
Update or Other Action |
2016 Draft Report for Remedial Action Operation and Land Use/Institutional Control at JBER received for review and comment. The Cleanup Complete Determination (with ICs), issued by the ADEC on 22 September 2005, agrees with the USAF's request that vadose zone soil remedial actions are complete for Site PL081 and that no further action is necessary at this site. Although PL081 Valve Pit 11 was not formally identified as a site until after the Operable Unit (OU) 6 ROD was signed, the 2005 PL081 Decision Document states that all groundwater contamination attributable to PL081 will be managed by the OU6 ROD. Therefore, groundwater contamination associated with PL081 is monitored as part of the LF04 South and WP14 groundwater monitoring program. Future
groundwater monitoring will be conducted as part of OU6 (source areas LF04 and WP14) and
the site known as PL081 will be administratively closed out (ADEC 2017).
The inspection of Site PL081 revealed no evidence of ground disturbance at this site. Revegetation
appeared to be occurring at the site and the monitoring wells located at the site were observed to be in good condition. Warning signs alerting visitors to the active onsite pipeline appeared to be in good condition and no erosion was observed along the access roads. Photographs 1 through 5 in Photograph Log A1 present the general condition of Site PL081.
See site file for additional information. |
Louis Howard |
| 4/3/2017 |
Document, Report, or Work plan Review - other |
ADEC letter to AFCEC approving the Environmental LTM report as final. |
Louis Howard |
| 8/21/2017 |
Update or Other Action |
Draft Supplemental WP Remedial Action Operations, LU/ICs received for various JBER-E and JBER-R sites for review and comment: PL081, CG551, ST408, CG530, SO510, SS522, SO507, SS418, TS003, CG543, CG529, TU107, ST048, CG509, SO508, SO549, AT035, AT029, SS019, DP009, LF002, CG536, CG539, CG702, SO544, SO547, CG704, CG527, SO501, TU064, SS013, SS014, and SS041.
See site file for additional information. |
Louis Howard |
| 8/27/2021 |
Document, Report, or Work plan Review - other |
DEC reviewed and provided comments on Draft JBER SA110, OW118, and PL081 Soil Investigative Derived Waste Per- and Polyfluoroalkyl Substances Letter Work Plan. The work plan describes steps and processes to be conducted to perform per- and polyfluoroalkyl substances (PFAS) characterizations of soil IDW associated with the remedial investigations of site SA110 and the site characterizations performed at sites OW118 and PL081. |
William Schmaltz |
| 8/21/2023 |
Document, Report, or Work plan Review - other |
DEC reviewed PL081 Site Characterization Report. Report summarizes characterization activities that took place between June 1 2020 and October 2020. Horizontal extend of POL at the site has not been full delineated to the northwest, north, northeast, and east of the site. |
William Schmaltz |
