| Action Date |
Action |
Description |
DEC Staff |
| 12/11/1997 |
Update or Other Action |
Under a grant from NOAA, the St. George Tanaq Corporation retained Polarconsult Alaska, Inc. during 1996 and 1997 to conduct a St. George Island environmental site investigation. As such, Polarconsult conducted the St. George School site assessment and UST removal activities during the summer of 1997. The date of the UST installation is unknown but presumably occurred some time between the initiation of school construction and the early 1960s. The UST was used until the late 1970s. It was unregulated and did not have an Alaska Department of Environmental Conservation (ADEC) UST facility identification number. Prior to the UST removal, the tank was replaced by an aboveground storage tank (AST).
Initial observations at the site indicated the presence of soil stains around the UST fill and vent pipes. During UST removal, a light fuel odor and elevated field instrumentation readings indicated a fuel release occurred. Observations and field measurements suggested that the release probably originated from the ground surface and was likely the result from overfilling the tank. One excavation and sampling was conducted in an effort to remove the contaminated soil. The final extent of the excavation was the result of removing contaminated soil until further excavation impracticable. Polarconsult noted that the fuel contamination appeared to continue under the school.
Additionally, an immediately adjacent sewer line impeded further horizontal and vertical excavation. A total approximately 10 cubic yards of soil was removed from this site. DRO was the only analyte looked at with sample SS052/145 contained 5,000 mg/kg DRO and sample SS053/146 had 1,360 mg/kg DRO. Polarconsult recommended further investigation to determine the horizontal and vertical extent of contamination and to determine a remediation approach. Polar consult also recommended removing or relocating the sewer line before attempting further excavation. |
Ray Dronenburg |
| 11/30/2002 |
Update or Other Action |
In 2002, NOAA retained St. George Chadux Corporation (Chadux) and its subcontractor, Polarconsult, to remove additional PCS in the area of the former UST. Excavation was in the area of sample locations SS052/145 and SS053/146 to remove visibly contaminated soil exhibiting strong diesel odor. During separate incidences, the water and sewer lines traversing the excavation were breached.
A total of 29 cubic yards of contaminated soil was removed, final excavation depth was at 9ft (refusal). According to Polarconsult observations, contamination exists at depth (551 mg/kg DRO) which cannot be excavated. |
Louis Howard |
| 4/22/2004 |
Site Added to Database |
DRO contamination. |
Sarah Cunningham |
| 11/30/2004 |
Long Term Monitoring Established |
Groundwater well TPA22.1-MW-1 sampled once in 2001, 2002, twice in 2003 and 2004. Diesel range organics have not exceeded the cleanup level of 1,500 ug/L. Several other monitoring wells exist (i.e. TPA24-MW-1 to MW-3) down gradient of the school. GRO and DRO were either not detected or detected below Table C Groundwater cleanup levels. Water table elevation at TPA22.1-MW-1 is 5.47 ft. above mean sea level. Based on ground elevation of 43.46 ft. above mean sea level, groundwater is estimated to occur at approximately 38 ft. below ground surface (bgs). |
Louis Howard |
| 1/31/2005 |
Update or Other Action |
Formal Request for Conditional Closure School UST TPA Site no. 22-1 NOAA Site no. 22. Location: St. George Island, Alaska is approximately 800 miles southwest of Anchorage in the Bering Sea. On the island, the site is located in the eastern section of the City of St. George, approximately 620 feet (ft) south of the Bering Sea (56° 36’ 8.87” N latitude, 169° 32’ 38.98” W longitude; Figures 1 and 2).
Legal Property Description: The St. George School UST site is located in Tract 41 of Township 41 south, Range 129 west, Section 29 of the Seward Meridian, Alaska, as shown on the plat of rectangular net survey, officially filed February 15, 1985 (Figure 2). The federal government currently owns the surface and subsurface estate of this site.
Type of Release: Potential release mechanisms include diesel fuel spills associated with the filling of the school’s UST and leaks associated with fuel storage in the UST.
Prior to excavation activities, the locations of buried utilities and previous samples were determined. Chadux initiated excavation on July 30, 2002, completing it on August 1, 2002. Other associated site activities continued through August 5, 2002. Chadux removed previously placed backfill and placed it on a liner. Excavation then continued in the vicinity of former sample locations SS 052/145 and SS 053/146 to remove visibly contaminated soil exhibiting a strong diesel odor. During separate incidences, the water and sewer lines traversing the excavation were breached. Both were cut and removed from the excavation and reinstalled following excavation activities. Removal of the former UST fuel lines was also performed. Previously, the two 1/2-inch diameter copper supply and return fuel lines had been disconnected at both ends, drained, and sealed by crimping and folding. When uncovered in 2002, both lines were intact and in good condition with minor surface patina. There was no visual or olfactory evidence of any release, and seven samples from along the approximately 65 ft fuel line length did not indicate any contamination when field screened using a PID.
Soil excavation was conducted downward and outward until soil exceeding site cleanup levels was no longer evident or until the building foundation or refusal (i.e., competent scoria) was encountered. A total volume of 29 CY of PCS was removed. Final excavation depth at refusal was 9 ft bgs. According to Polarconsult observations, contamination continued vertically downward into the competent scoria and horizontally under the building foundation where it could not be removed with the available equipment.
The analytical data for confirmation samples collected from the final extent of excavation indicated that DRO remained at one location. Sample SG-22.1-004-0.5, collected at refusal, in scoria at the bottom of the excavation (8.6 ft bgs), contained 551 mg/kg DRO. GRO and BTEX constituents were not detected in any excavation confirmation samples.
The analytical data for the samples collected from the soil stockpiled on-site were compared to the ADEC Method Two cleanup levels and found not to exceed cleanup levels. Subsequently, this soil was used as backfill material at another TPA site. Laboratory results for the two samples collected from soils transported to the ADEC-approved PCS stockpile indicated that GRO and BTEX were not detected in either sample. DRO was detected in one sample, with a concentration of 37.9 mg/kg. As a result of the commingling of various TPA sites’ soils at the PCS stockpile, it is uncertain whether the soil from TPA 22-1 was treated in the ETC system or if it remains stockpiled, awaiting final disposition.
The excavation was backfilled with ETC-treated soil followed by a scoria cover. Final site grading was completed in accordance with the corrective action plan. Site revegetation was not pursued due to school district plans to renovate the school in 2003.
In accordance with paragraph 59 of the Two Party Agreement (NOAA 1996), NOAA requests written confirmation that NOAA completed all appropriate corrective action, to the maximum extent practicable, at the St. George School UST site, TPA Site 22-1/Site 22 in accordance with the Agreement and that ADEC grant a conditional closure not requiring further remedial action from NOAA. NOAA understands ADEC will/may require additional containment, investigation, or cleanup if subsequent information indicates that the level of contamination that remains does not protect human health, safety, or welfare, or the environment. |
Louis Howard |
| 2/11/2005 |
Cleanup Complete Determination Issued |
No further remedial action required since residual diesel contamination is underneath the school building foundation.
The following policy applies for soil regulated under 18 AAC 75 and 18 AAC 78 that is proposed for disposal off site from where it was generated. If the following criteria is met, ADEC approval and/or an institutional control(s) are not required: 1. The soil meets the most stringent Method Two, Migration to Groundwater, Table B2 cleanup level, and the most stringent standards for those chemicals under Table B1; 2. The soil may only be disposed of at any non-environmentally sensitive location in the Under 40" or Over 40" annual precipitation zone;
3. The soil is not placed within 100 feet of water wells, surface waters, and drainage ditches; and 4.The written approval from the landowner of the off-site location is required.
The off site disposal of all other soil subject to the site cleanup rules that does not meet the criteria above shall be reviewed by the ADEC project manager in order to determine if the off-site disposal action poses a current or future risk to human health or the environment. The final approval to dispose of soil off site that does not meet the criteria shall be made by the ADEC Section Manager.
Terms used in this document have the meaning given in 18 AAC 75.990 including: “environmentally sensitive area” means a geographic area that, in the department's determination, is especially sensitive to change or alteration, including:
(A) an area of unique, scarce, fragile, or vulnerable natural habitat;
(B) an area of high natural productivity or essential habitat for living organisms;
(C) an area of unique geologic or topographic significance that is susceptible to a discharge;
(D) an area needed to protect, maintain, or replenish land or resources, including floodplains, aquifer recharge areas, beaches, and offshore sand deposits;
(E) a state or federal critical habitat, refuge, park, wilderness area, or other designated park, refuge, or preserve; and
(F) an area that merits special attention as defined at 6 AAC 80.170 (Repealed see AS 46.40.210(1))
“area which merits special attention” means a delineated geographic area within the coastal area which is sensitive to change or alteration and which, because of plans or commitments or because a claim on the resources within the area delineated would preclude subsequent use of the resources to a conflicting or incompatible use, warrants special management attention, or which, because of its value to the general public, should be identified for current or future planning, protection, or acquisition; these areas, subject to council definition of criteria for their identification, include:
(A) areas of unique, scarce, fragile or vulnerable natural habitat, cultural value, historical significance, or scenic importance;
(B) areas of high natural productivity or essential habitat for living resources;
(C) areas of substantial recreational value or opportunity;
(D) areas where development of facilities is dependent upon the utilization of, or access to, coastal water;
(E) areas of unique geologic or topographic significance which are susceptible to industrial or commercial development;
(F) areas of significant hazard due to storms, slides, floods, erosion, or settlement; and
(G) areas needed to protect, maintain, or replenish coastal land or resources, including coastal flood plains, aquifer recharge areas, beaches, and offshore sand deposits. |
Louis Howard |
| 2/11/2005 |
Institutional Control Record Established |
In the event that the remaining contaminated soil becomes accessible by the removal of the soil located in the vicinity of the School Underground Storage Tank Site TPA 22-1, the land owner and/or operator will be required under 18 AAC 75.300 to notify the Department. Also, any transport or disposal of contaminated soil excavated from the site requires approval from the Department in accordance with 18 AAC 75.325(i). |
Louis Howard |
| 6/20/2005 |
Update or Other Action |
Request for Conditional Closure School AST, NOAA Site 33. On the island, the site is located in the eastern section of the City of St. George, approximately 620 feet (ft) south of the Bering Sea (56° 36’ 8.87” N latitude, 169° 32’ 38.98” W longitude. Legal Property Description: The area of excavation is located at Lot 2 of Tract 41, East Landing Subdivision, Seward Meridian, Alaska, Latitude 56º 36’ 8.87” N, Longitude 169º 32’ 38.98” W, WGS 84, as shown on the plat
of rectangular net survey, officially filed February 15, 1985 (Black-Smith & Richards). The federal government currently owns the surface and subsurface estate of this site. At its discretion, NOAA established a boundary for this TPA site based on site characterization data and historic information.
Type of Release: Potential release mechanisms include: 1) leaks associated with the filling, storage and dispensation of heating oil in an aboveground fuel storage tank (AST) and its appurtenances; and 2) heating oil leaks from the tank. The site is approximately 75 feet (ft) east of the School UST site. NOAA subsequently determined that PCS may be present below and near the current AST, based on known fuel storage tank overfueling practices on St. George Island and the poor physical condition of the AST. The AST was in service prior to March 15, 2001, and any contamination due to releases at the site prior to that date are the responsibility of the U.S. Government pursuant to Public Law 106-562. The Pribilof Islands
School District decided to decommission the AST as part of a large renovation project in 2003. NOAA, in consultation with the District, decided to remediate PCS associated with the AST subsequent to the AST decommissioning.
NOAA removed an estimated 21 cubic yards of PCS from the site, backfilling the site with clean soil. This PCS is stockpiled at NOAA’s long-term PCS stockpile and awaits final disposal. No site-specific contaminants above ADEC Method Two at the site.
In accordance with paragraph 59 of the Two Party Agreement (NOAA 1996), NOAA requests written confirmation that NOAA completed all appropriate corrective action, to the maximum extent practicable, at the School AST, NOAA Site 33 in accordance with the Agreement and that ADEC grant a conditional closure not requiring further remedial action from NOAA. NOAA understands ADEC will/may require additional containment, investigation, or cleanup if subsequent information indicates that the level of contamination that remains does not protect human health, safety, or welfare, or the environment. |
Louis Howard |
| 3/25/2008 |
Document, Report, or Work plan Review - other |
Staff reviewed and commented on the Final Groundwater Monitoring Technical Memorandum-St. George Island, Alaska Dated February 20, 2008. The report documents the sampling of eleven (11) groundwater monitoring wells in November 2007 on St. George Island. The main contaminants of concern in the groundwater are: diesel range organics, gasoline range organics, benzene, and perchloroethylene (PCE). The contamination is associated with Two-Party Agreement (TPA) Sites: no. 1 Former Diesel Tank Area, no. 2 Drum Storage Area, no. 8 Active Power Plant, no. 22-1 School underground storage tank (UST) and the village monitoring wells.
General Comments-In the future, ADEC requests NOAA include as part of the laboratory data reports: the CS Lab Approval Number (e.g. UST-030), lab approval expiration date, and the name of the person authorizing release of laboratory data (normally a cover page containing this information).
Note: The “raw” analytical data (Appendix C-Data Deliverables Package starting on page 88 of 490 pages), e.g. bench sheets, chromatograms, calibration data, etc., are not required submittals to ADEC, however, must be retained on file by the laboratory for at least ten (10) years after the analysis date (i.e. 2017). The hard copy report/technical memorandum sent to ADEC need not include the “raw” analytical data, but NOAA may choose to include it on CD-ROM.
Finally, ADEC requests NOAA provide some qualitative statements in subsequent reports/technical memorandum regarding groundwater contamination at each site stating if the groundwater monitoring indicates a contamination trend and if the concentration trend
(1) is increasing or
(2) is stable or decreasing, and that hazardous substance migration is not occurring.
2.1 Groundwater Sampling Page 8-The text states several hinges were broken and rusted, unbroken hinges made access to the PVC inner casings difficult. Several steel monument caps could not be closed and locked, thus access no longer is restricted. ADEC requests NOAA to replace all broken and rusted hinges to allow the monument caps to be closed and locked, preventing unauthorized access to the monitoring wells.
2.3 Analytical Procedures Page 9- Attached you will find an updated Table 1 part A and part B, from the UST Procedures Manual. Please use this as a desk reference until the UST Procedures Manual is revised, sometime in the future. SW846 was revised in 2007 and many of the corresponding changes have been captured on the new table. ADEC has added new information for pesticides, herbicides, and mercury and ADEC has updated the determinative methods and preservation requirements.
|
Louis Howard |
| 9/20/2008 |
Update or Other Action |
The U.S. Department of Commerce, National Oceanic and Atmospheric Administration (NOAA) Pribilof Project Office is responsible for site characterization and restoration on St. George Island, Alaska. Although NOAA has attempted to meet State of Alaska soil cleanup levels and has removed contaminated soil to the maximum extent practicable, residual contamination remains at some St. George Island sites. This report documents the nature of known or potential residual soil and groundwater contamination at NOAA-remediated sites and presents the rationale for leaving the contamination in place.
A 1,000-gallon UST was located at Site 22. The UST was installed on the south side of the St. George School in the early 1960s, and subsequently removed in 1997 along with approximately ten (10) yd3 of DRO contaminated soil. In 2002, an additional twenty-nine (29) yd3 of contaminated soil was removed from site. Contaminated soil removal was constrained by the building’s foundation, by nearby buried utilities, and by equipment refusal reached at approximately nine feet bgs. Contaminated soil was removed to the extent practicable; however, confirmation samples indicated DRO concentrations of 5,000 mg/kg at equipment refusal depth, and 1,360 mg/kg near a water line. GRO and BTEX were not detected in confirmation sample analyses.
Groundwater monitoring well TPA22.1-MW-1 was installed at Site 22 in 2001 to determine if contaminants had migrated from the site to the water table. Groundwater samples were collected from this well from 2001 through 2004 and analyzed for DRO, GRO, VOC, SVOC, and metals. Sample analytical results indicated all contaminants were either non-detect or detected at concentrations below ADEC cleanup criteria. Monitoring well TPA22.1-MW-1 has been retained to monitor for contaminant migration from Site 8, Active Power Plant in accordance with an ADEC approved long-term groundwater monitoring plan.
AND
A 500-gallon diesel fuel UST was located at Site 23. The UST, likely installed in the early 1960s, was removed in 1997 along with approximately 341 yd3 of DRO contaminated soil. Contaminated soil was removed to the extent practicable; however, excavation efforts were constrained by the building’s foundation and limited by the reach of the equipment on-island. Confirmation samples indicated DRO concentrations of up to 4,360 mg/kg remain next to the building’s foundation at ten feet bgs and up to 7,330 mg/kg at a depth of eighteen feet bgs.
AND
A 1,000-gallon diesel fuel UST was located at Site 24. The UST, likely installed in the early 1960s, was removed in 1997 along with approximately 402 yd3 of DRO contaminated soil. The 1997 contaminated soil excavation started at the UST location and expanded horizontally until further excavation was not practicable due to the risk of undermining the building’s foundation, interference from nearby septic tanks, and concerns about placing equipment too close to the cliff on the north side of the site. The excavation continued vertically until equipment refusal was encountered at depths ranging from 6.7 to 14.4 feet bgs. Confirmation samples indicated DRO concentrations of up to 730 mg/kg next to the building’s foundation at 8 feet bgs and up to 20,500 mg/kg at a refusal depth of 9.4 feet bgs. Analytical results indicated BTEX constituents either non-detect or well below Method Two criteria.
Monitoring well TPA22.3-MW-1 was installed at the site in 2001 to determine if contaminants had migrated to the groundwater. Groundwater samples were collected from this well from 2001 through 2004 and analyzed for DRO, GRO, VOC, SVOC, and metals. Sample analytical results indicated all contaminants were either non-detect or detected at concentrations below ADEC cleanup criteria. Based on a determination that groundwater in the vicinity of Site 24 had not been adversely impacted, this monitoring well was decommissioned in 2005 and removed in 2006 in accordance with an ADEC approved long-term groundwater monitoring plan.
AND
A 4,000-gallon gasoline UST was located at Site 25. The UST, likely installed in the 1960s, was removed in 1996 by the City of St. George. In 1997, test pits were excavated at the former location of the UST and associated appurtenances; no soil stains, odors or other indications of a fuel release were observed in the test pits or on the ground surface. Soil samples were collected from the test pits and analyzed for GRO. Analytical results were all non-detect with one exception at thirteen (13) mg/kg GRO. The Method Two criterion for GRO is 300 mg/kg. No further action was deemed necessary at this site. |
Louis Howard |
| 9/26/2008 |
Update or Other Action |
Summary of Residual Soil Contamination and Buried Solid Wastes at NOAA Cleanup Sites on St. George Island. NOAA Site No. 22/TPA Site No. 22-1, School UST: contaminated soil, UST/AST pipeline. Diesel range organics (DRO) contaminated soil remains adjacent to the southwest corner of the school at a refusal depth of approximately 9 feet bgs, and potentially beneath the school building. Deed restriction to future landowner (State of Alaska).
Site status as of September 26, 2008: NFRAP 04/08/2004; NFRAP 02/11/2005 Property Owners: NOAA.
ALSO includes
NOAA Site 23 TPA Site 22-2 Current Carpenter Shop USTs: contaminated soil, UST/AST/Pipeline. DRO contaminated soil remains adjacent the east end of the Carpenter Shop building where further excavation could jeopardize foundation stability, and at depth exceeding 15 feet bgs. Deed Notice. Site status as of September 26, 2008-NFRAP 08/19/2003. Property owners: Tanaq/TAC.
NOAA Site 24 TPA Site no. 22-3 Shop/Store UST. Contaminated soil; UST/AST/Pipeline. Site conditions as of August 6, 2008: DRO Contaminated soil remains near northwest corner of the building's foundation, near a cliff edge and at refusal depths of 7 to 14 feet bgs. Deed notice. Site status as of September 26, 2008: NFRAP 10/08/2004. Property owner: Tanaq/TAC.
NOAA Site 25 TPA Site No. 22-4 Old Airport Hangar UST. Surface debris, contaminated soil, UST/AST/Pipeline. Clean closure. Site Status as of September 26, 2008: NFRAP 03/10/2003. Propery owner: City of St. George. |
Louis Howard |
| 4/29/2010 |
Update or Other Action |
Annual groundwater monitoring report received. TPA Site 22-1 is proximal to the St. George Public School. A former 1,000-gallon diesel fuel UST, installed in the 1960s, once supplied fuel for the school. In 1997, NOAA contracted St. George Tanaq Corp. to remove the tank and approximately 10 cubic yards of DRO contaminated soil (NOAA, 2005). During tank removal, inspections discovered petroleum contaminated soils, likely resulting from overfilling of the UST.
Monitoring well TPA22.1-MW-1 was installed to monitor the potential migration of fuel in the
groundwater at a former UST location at the St. George Public School, designated TPA Site
22.1. During the December 2009 sampling event, the groundwater at TPA22.1-MW-1 was
sampled for GRO, DRO, benzene, PCE, and RRO. No analyte concentrations exceeded ADEC cleanup levels. No analytes at TPA Site 22.1 met the requirements to perform a statistical trend analysis.
From 2001 to 2003, additional wells were installed as part of a monitoring well network. These
wells are not associated with specific TPA sites (NOAA, 2005). The wells were sampled for
GRO, DRO, VOCs, SVOCs, and metals and results indicated that there were no detectable
concentrations of GRO, DRO, and VOCs. Detected SVOCs and metal concentrations were
below ADEC cleanup criteria.
Monitoring well VIL-MW-3 was installed as part of an expanded groundwater monitoring well
network. During the December 2009 sampling event, the groundwater at monitoring well VILMW-
3 was sampled for GRO, DRO, benzene, PCE, and RRO. No analytes were reported to exceed ADEC cleanup levels. Only one analyte at the Village Monitoring Wells met the requirements necessary for a statistical trend analyses. DRO concentrations at VIL-MW-3 were analyzed for a monotonic trend. DRO concentrations at VIL-MW-3 were shown to be increasing. No trends at the Village Monitoring Wells are significant at a < 0.05 and therefore do not meet the data quality requirements to be considered statistically valid for the purposes of this report.
Additional sampling and analysis will further verify the contaminant trends presented in this
report. Factors influencing groundwater contaminant concentrations such as water table
variations as related to seasonal changes and sampling location relative to the water table were
neglected in the statistical analysis owing to data availability. |
Louis Howard |
| 2/10/2011 |
Update or Other Action |
Staff received the Groundwater Monitoring Mid-Year Report dated January 2011. This report presents the results of the June 2010 St. George monitoring well sampling event and statistical analysis of trends in COC concentrations. Groundwater sampling procedures and protocols used for this project follow the NOAA Master Quality Assurance Plan, the Final Long-Term Groundwater Monitoring Plan, St. George Island, Alaska, and the Groundwater Monitoring Work Plan, St. George Island, Pribilof Islands, Alaska prepared by BSI. Trend analysis was performed using Mann-Kendall statistical methods which are described by Boyaciogly and Boyaciogly.
The purpose of continued groundwater monitoring on St. George is to monitor DRO, GRO, RRO, benzene, and PCE concentrations in groundwater at 11 monitoring wells, which are part of a monitoring well network. Hydrocarbon and PCE concentrations were detected in groundwater at wells installed in two locations in the village: the Former Diesel Tank Farm Two-Party Agreement (TPA) Site 1 and Active Power Plant TPA Site 8. At the Former Drum Storage Area TPA Site 2 and the School underground storage tank (UST) TPA Site 22-1 only hydrocarbon analytes were detected.
TPA Site 22-1 is proximal to the St. George Public School. A former 1,000-gallon diesel fuel
UST, installed in the 1960s, once supplied fuel for the school. In 1997, NOAA contracted St.
George Tanaq Corp. to remove the tank and approximately 10 cubic yards of DRO contaminated
soil. During tank removal, inspections discovered petroleum contaminated soils, likely resulting from overfilling of the UST.
Monitoring well TPA22.1-MW-1 was installed to monitor the potential migration of fuel in the
groundwater at a former UST location at the St. George Public School, designated TPA Site
22.1. During the June 2010 sampling event, the groundwater at TPA22.1-MW-1 was sampled for
GRO, DRO, benzene, PCE, and RRO. No analyte concentrations exceeded ADEC cleanup levels. No analytes at TPA Site 22.1 met the minimum requirements to perform a statistical trend analysis. |
Louis Howard |
| 3/24/2011 |
Update or Other Action |
NOAA submits proposed changes to groundwater monitoring for St. George and St. Paul Island.
3) Continue semi-annual monitoring of DRO/RRO and GRO concentrations at the ten wells remaining after decommissioning TPA22.1-MW-1.
Reason: Seven wells will remain to monitor for plume movement (wells TPA1-MW-5, TPA2-MW-2, TPA8-MW-4, TPA8-MW-9, TPA8-MW-13, TPA8-MW-14, and VIL-MW-3); three wells will remain to establish DRO/RRO and GRO concentrations trends (TPA1-MW-2, TPA1-MW-3, TPA2-MW-1). Even though GRO is strongly trending downward at TPA1-MW-3, it will continue to be monitored at this well for contract simplicity.
|
Louis Howard |
| 4/4/2011 |
Update or Other Action |
Annual Groundwater monitoring report received. The purpose of continued groundwater monitoring on St. George is to monitor DRO, GRO, RRO, benzene, and PCE concentrations in groundwater at 11 monitoring wells, which are part of a monitoring well network. Hydrocarbon and PCE concentrations were detected in groundwater at wells installed in two locations in the village: the Former Diesel Tank Farm Two-Party Agreement (TPA) Site 1 and Active Power Plant TPA Site
8. Only hydrocarbon analytes were detected at the Former Drum Storage Area TPA Site 2 and
the School underground storage tank (UST) TPA Site 22-1.
Monitoring well TPA22.1-MW-1 was installed to monitor the potential migration of fuel in the
groundwater at a former UST location at the St. George Public School, designated TPA Site 22.1. During the November 2010 sampling event, the groundwater at TPA22.1-MW-1 was sampled for GRO, DRO, benzene, PCE, and RRO. No analyte concentrations exceeded ADEC cleanup levels. No analytes at TPA Site 22.1 met the minimum requirements to perform a statistical trend analysis.
Village Monitoring Wells
Monitoring well VIL-MW-3 was installed as part of an expanded groundwater monitoring well network. During the November 2010 sampling event, the groundwater at monitoring well VIL-
21MW-3 was sampled for GRO, DRO, benzene, PCE, and RRO.
No analytes were reported to exceed ADEC cleanup levels. Only one analyte at the Village Monitoring Wells met the requirements necessary for a statistical trend analysis. DRO concentrations at VIL-MW-3 were analyzed for a monotonic trend, the results of which are presented in Table 4-2. The DRO concentration trend at VIL-MW-3 was shown to be increasing. No trends at the Village Monitoring Wells are significant at a < 0.05 and therefore do not meet the data quality requirements to be considered statistically valid for the purposes of this report.
DRO
Though sufficient data was available to calculate these trends, due to the small number of data points and other factors no DRO trends on St. George meet the data quality requirements for this project to be considered statistically valid. These DRO trends should not be used to draw conclusions or make decisions.
GRO
Five of the eleven subject monitoring wells on St. George Island, TPA1-MW-2, TPA1-MW-3,
TPA2-MW-1, TPA2-MW-2, and TPA8-MW-4 had GRO concentrations statistically analyzed
for monotonic trends. Three of the wells had downward trending GRO concentrations; one well
had an upward trending GRO concentration; and one well had a GRO concentration trend of zero. The GRO trend at TPA1-MW-3 was the first GRO trend to be calculated with a significance of 95% or greater in St. George. The GRO concentration is trending downward, and at 95% or greater significance, meets the data quality requirements to be considered statistically valid for this project.
Benzene and PCE
Two wells were statistically analyzed for monotonic trends in the concentrations of benzene and
PCE; TPA1-MW-3 for benzene, and TPA8-MW-4 for PCE. Analyses showed that the concentrations of benzene and PCE are trending downward and that the benzene trend is significant at 95% or greater, meeting the data quality requirements to be considered statistically valid for this project.
RRO
Though sufficient data was available to calculate these trends, due to the small number of data points and other factors no RRO trends from the St. George wells meet the data quality requirements for this project to be considered statistically valid. These RRO trends should not be used to draw conclusions or make decisions. Additional sampling and analysis will further verify the contaminant trends presented in this report. Factors influencing groundwater contaminant concentrations such as water table variations as related to seasonal changes and sampling location. |
Louis Howard |
| 8/11/2011 |
Update or Other Action |
Staff received the draft LTM plan for review and comment. This long-term groundwater monitoring plan completely replaces and combines National Oceanic and Atmospheric Administration (NOAA) Long-Term Groundwater Monitoring Plan, St. Paul Island, Alaska dated August 29, 2005 and NOAA Long-Term Groundwater Monitoring Plan, St. George Island, Alaska also dated August 29, 2005.
This plan specifies the monitoring requirements for the remaining 28 wells on St. Paul Island and 10 wells on St. George Island. Some wells are utilized as sentinels to monitor for contaminant plume migration while the rest are used to monitor contaminant concentration trends to evaluate the effectiveness of past remedial actions and natural attenuation of contaminants. The requirements specified in this plan will remain in effect until evaluation of contaminant concentration trends indicate a revision is warranted. All revisions to this plan shall be reviewed and concurred with by ADEC prior to becoming final.
Based on the results of groundwater monitoring from June 2006 to November 2010, the following 10 wells will be retained for further monitoring: TPA1-MW-2, TPA1-MW-3, TPA1-MW-5, TPA2-MW-1, TPA2-MW-2, TPA8-MW-4, TPA8-MW-9, TPA8-MW-13; TPA8-MW-14, and VIL-MW-3 (Figure 2-5). Sampling and subsequent reports to ADEC will be accomplished in accordance with Section 3.0 and as follows:
-Semiannual sampling at all wells for DRO, GRO, and RRO.
-Benzene will be sampled/analyzed for every five years to verify continued decreasing concentration levels at TPA1-MW-3. The next sampling round will occur no later than November 2015.
-PCE will be dropped as an analyte.
|
Louis Howard |
| 9/29/2011 |
Update or Other Action |
Staff received the draft Long Term Groundwater Monitoring Plan St. Paul and St. George Islands, Alaska, September 2011. This plan specifies the monitoring requirements for the remaining 28 wells on St. Paul Island.
In 2001, NOAA installed monitoring well TPA22.1-MW-1 to check for groundwater impact due to the
spills associated with the St. George School UST; the groundwater was found to be uncontaminated.
From June 2006 to November 2010 this well was utilized as a sentinel for plume movement out of TPA Site 8. Sample analytes were DRO, GRO, benzene, PCE, and RRO. All sample analysis results have been non-detect or detected at very low concentrations (NOAA 2011b). Contaminant trend analysis cannot be performed due to the lack of sample results above MRL. Therefore, monitoring at this well will be discontinued and the well decommissioned.
Sampling and subsequent reports to ADEC will be accomplished in accordance with Section 3.0 and as follows:
• Semiannual sampling at all wells for DRO, GRO, and RRO.
• Benzene will be sampled/analyzed for every five years to verify continued decreasing
concentration levels at TPA1-MW-3. The next sampling round will occur no later than November 2015.
• PCE will be dropped as an analyte. |
Louis Howard |
| 9/14/2012 |
Update or Other Action |
Draft GW Monitoring Annual Report received.
Monitoring well TPA22.1-MW-1 was installed to monitor the potential migration of fuel in the
groundwater at a former UST location at the St. George Public School, designated TPA Site 22.1. During the June 2012 sampling event, the well was decommissioned according to ADEC guidelines. A well decommissioning report was submitted to ADEC in July 2012. |
Louis Howard |
| 6/14/2013 |
Exposure Tracking Model Ranking |
Initial ranking with ETM completed for source area id: 73792 name: auto-generated pm edit TPA 22-1 STG School UST Site |
Louis Howard |
| 9/30/2013 |
Document, Report, or Work plan Review - other |
Staff reviewed the proposal by NOAA to continue groundwater sampling under the existing approved monitoring plans. ADEC has reviewed the information provided and approves the work as a continuation of the three existing work plans for groundwater monitoring on the Pribilof Islands. |
Louis Howard |
