| Action Date |
Action |
Description |
DEC Staff |
| 8/11/2006 |
Site Added to Database |
Site added to the database. |
Mitzi Read |
| 8/22/2007 |
Site Characterization Workplan Approved |
DEC has completed a review of a work plan which was prepared by BGES Inc., dated August 16, 2007 and received by DEC on August 17, 2007. BGES Inc. proposes within the work plan to do the following:
1. Advance one soil boring approximately 16 feet below ground surface and collect soil samples continuously to be field screened for volatile organic compounds with a photoionizing detector.
2. Collect one soil sample during soil boring advancement to be submitted to a DEC approved laboratory to be analyzed for GRO, DRO, BTEX, and total lead.
3. Complete the soil boring as a monitor well and after developing the well collect a groundwater sample to be analyzed for GRO, DRO, BTEX, and total lead by a DEC approved laboratory.
4. Construct a conceptual site model.
5. Issue a report summarizing site investigative findings.
|
Todd Blessing |
| 9/11/2007 |
Update or Other Action |
DEC reviewed a letter from Don Keefer, Private Development Manager, Municipality of Anchorage, which was dated August 13, 2007. Mr. Keefer notified DEC of their intent to proceed with Gambell Street Improvements. In addition, Mr. Keefer referenced a letter from Stonebridge Companies acknowleging Denali Lodging, LLC's acceptance of any costs associated with environmental cleanup. |
Todd Blessing |
| 10/9/2007 |
Potentially Responsible Party/State Interest Letter |
DEC issued a state interest letter to Navin C. Diamond requesting he identify when Denali Lodging LLC acquired the subject property, and summarize their activities on the land since they acquired it. If hazardous material has been or is being stored or used on the property, DEC requested that Mr. Diamond please describe the circumstances and time frame of storage and/or use. |
Todd Blessing |
| 11/28/2007 |
Exposure Tracking Model Ranking |
Initial ranking. |
Todd Blessing |
| 2/5/2008 |
Update or Other Action |
DEC issued a letter to the Municipality of Anchorage notifying MOA of their potential responsible party status and requesting that MOA hire a qualified third party to submit a site investigation work plan to DEC by May 30, 2008. |
Todd Blessing |
| 4/10/2008 |
Update or Other Action |
DEC recieved a letter from Sharon A. Walsh of Muniticipality of Anchorage (MOA, wich was dated February 5, 2008. Ms. Wash stated that MOA aquired the subject property on October 14, 1970. MOA was unaware of contamination at the subject property until 2005 when Denali Lodging LLC started construction of the Embassy Suites project. MOA requested that DEC recognize that the presence of hazardous or toxic substances is the results of acts or omissions of third parties not in privity with the MOA. |
Todd Blessing |
| 9/3/2008 |
Site Characterization Workplan Approved |
DEC has reviewed and approved Shannon and Wilson’s (S&W's) “Groundwater Monitoring Well Installation and Sampling Work Plan” dated August 27, 2008. S&W proposes to do the following:
1. Advance five soil borings that will be completed as monitor wells
2. Collect soil and groundwater samples to be analyzed for contaminants of concern (COCs).
3. Determine groundwater flow direction and distance to nearest drinking water well
4. Identify any occupied buildings within 100 feet of contaminated soil or groundwater.
5. Develop a conceptual site model according to CSP guidance.
|
Todd Blessing |
| 2/20/2009 |
Update or Other Action |
DEC staff reviewed Shannon and Wilson’s “Phase II Environmental Site Assessment, 600 East Benson Boulevard Anchorage, Alaska” dated December, 2008. Shannon and Wilson (S&W) documented the advancement of five soil borings that were eventually completed as groundwater monitoring wells. Benzene was detected at levels that exceed CSP established cleanup values in a soil sample collected from B6S4 from between 7.5 and 9.5 feet below ground surface (bgs). Groundwater samples were collected from the five recently installed monitoring wells (MW2 through MW6) as well as an existing monitoring well (MW1). In four of the wells (MW-1, MW-2, MW-4, and MW-5) the levels of contaminants (i.e. GRO, DRO, RRO, and BTEX) exceeded DEC’s cleanup levels established for groundwater ingestion. The primary contaminant source area appears to be located near MW1.
S&W personnel conducted a limited drinking water well survey around the project site by reviewing Anchorage Water and Wastewater Utility’s (AWWU’s) 2001 Mapbook within the city blocks bounded by East Northern Lights Boulevard, Seward Highway, East 42nd Avenue, and Denali Street. Water mains were identified along each major road. Businesses occupying each building within the reviewing area were telephoned and asked if they utilized water provided by AWWU. According to the people contacted, each building is connected to city water and does not utilize a drinking water well.
S&W personnel prepared a conceptual site model in accordance with DEC guidance. The following exposure pathways were determined to be complete:
• Incidental Soil Ingestion
• Ingestion of Groundwater
• Dermal Absorption of Contaminants in Groundwater
• Inhalation of Outdoor Air
• Inhalation of Indoor Air
DEC issued a letter on February 20, 2009 requesting that MOA issue a site investigation work plan to DEC by May 30, 2009.
|
Todd Blessing |
| 7/20/2009 |
Site Characterization Workplan Approved |
DEC staff reviewed and conditionally approved Shannon and Wilson’s “Site Characterization Work Plan, 600 East Benson Boulevard, Anchorage, Alaska” dated July 1, 2009. Shannon and Wilson (S&W) proposes to advance two soil borings that will be completed as groundwater monitoring wells. One soil sample from each boring will be selected based on field screening results and analyzed for GRO, DRO, RRO, and BTEX. Groundwater samples will be collected from six existing wells and the two newly installed wells and be analyzed for GRO, DRO, RRO, and BTEX. S&W also proposes to install two soil gas probes by utilizing a direct push drill rig. Soil gas will be extracted from each location and screened for VOC’s with a photoionizing detector. Analytical samples will be collected with sorbent tubes utilizing EPA’s TO-17 method.
DEC issued an approval letter on July 20th, approving of the subject work plan provided: • S&W will install nested soil gas probes at depths of 2 to 5 feet and 10 to 15 feet below ground surface;
• Soil gas samples will be collected from the shallow and deep nested implant pair of each soil gas probe to be analyzed for BTEX;
• S&W will conduct leak detection procedures for each soil gas probe in accordance with CSP’s July 2009 Vapor Intrusion Guidance Document; and
• S&W will notify CSP 48 hours prior to implementing approved work plan so CSP can inspect work activities
|
Todd Blessing |
| 5/11/2010 |
Update or Other Action |
DEC staff completed a review of Shannon and Wilson’s “Site Characterization Report, 600 East Benson Boulevard, Anchorage, Alaska” dated February 2010. Shannon and Wilson's (S&W) site characterization efforts included the advancement of one soil boring which was completed as a monitoring well (designated MW7), the installation of two soil gas probes (designated SGP1and SGP2), and the collection of soil, soil gas, and groundwater samples to be analyzed for contaminants of concern. In the one soil sample collected, no contaminants of concern were detected above CSP regulatory criteria. In groundwater samples, the levels of GRO, DRO, benzene, and toluene exceeded CSP cleanup criteria for samples collected from MW1. Benzene was also detected above CSP cleanup criteria in monitoring well MW4. Groundwater elevations suggest groundwater flow is to the northwest. Soil gas samples were collected from each soil gas probe and analyzed for oxygen and helium by ASTM method D-1946 and for volatile organic compounds by NIOSH method 1501 modified. Following review of this data, CSP has determined that the oxygen and helium data is rejected since the samples (i.e. tedlar bags) had released air prior to its receipt by the laboratory. The volatile organic compound soil gas data revealed elevated levels of BTEX in one sample probe (i.e. SCPI-1) and nondetect in the other (i.e. SCP2-1). |
Todd Blessing |
| 9/7/2012 |
Update or Other Action |
DEC staff issued a letter to the MOA to conduct a site investigation and do the following:
• Resample groundwater from monitoring wells MW-1, MW-2, MW-4, and MW-5 to be analyzed for GRO, DRO, and BTEX by DEC approved methods;
• Resample soil gas from probes SCP1 and SCP2 to be analyzed by EPA method TO-15 in accordance with CSP guidance;
• Construct a conceptual site model (CSM) in accordance with CSP Guidance
|
Todd Blessing |
| 11/5/2012 |
Update or Other Action |
Staff reviewed and approved of BGES' work plan for groundwater and soil gas sampling. BGES willl inspect existing monitoring wells, collect a groundwater sample from each of four existing groundwater monitoring wells, collect soil gas samples from existing soil gas vapor monitoring points, and and prepare a report of their findings. This work plan satisfies DEC's request for a site investigation that was discussed in our September 7, 2012 letter. |
Todd Blessing |
| 4/16/2013 |
Site Characterization Report Approved |
Reviewed February 2013 Groundwater Monitoring and Soil Gas Sampling report, prepared by BGES under contract to Dowl HKM submitted by Dowl on behalf of the MOA. Groundwater samples were collected from MW1, MW2, MW4, and MW5, and soil gas samples were collected from SGP1 and SGP2. The groundwater results exceed the 18 AAC 75.345 Table C levels in MW1 for GRO, DRO, benzene, and toluene, and in MW5 for benzene. The groundwater results in MW1 are less than the concentrations found in the December 2008 sampling by factors of approximately 1.5 to 6. In the soil gas sample and duplicate collected from SGP1, concentrations of five analytes (hexane, cyclohexane, benzene, ethylbenzene, total xylenes, and 1,3,5-trimethlybenzne) exceed the ADEC soil gas target level. Benzene concentration in the samples from SGP1 is 110,000 µg/m^3. In SGP2, dichlorodiflouromethane (Freon) concentration exceeds the ADEC soil gas target level. |
Jacob Gano |
| 6/6/2013 |
Update or Other Action |
Letter sent to MOA (Mike Krueger at Department of Public Works) requesting a work plan for additional soil gas sampling to verify previous results. |
Jacob Gano |
| 1/21/2014 |
Document, Report, or Work plan Review - other |
ADEC received a report for the collection of soil gas samples at the Gambell Street Right of Way. Freon 12, hexane, cyclohexane, benzene, toluene, ethylbenzene, and xylenes were detected in soil gas at concentrations exceeding the Vapor Intrusion Target Levels. |
Meghan Dooley |
| 2/3/2014 |
Document, Report, or Work plan Review - other |
ADEC received a "ADEC Database Review and Aerial Photograph Review" for the Gambell Street Right of Way. The report, completed in 2006 for the MOA, shows an aerial photo of the site and surrounding area in 1964. Quonset huts and surface debris are visible at or adjacent to the site. |
Meghan Dooley |
