| Action Date |
Action |
Description |
DEC Staff |
| 12/23/2014 |
Site Added to Database |
A new site has been added to the database |
Mitzi Read |
| 12/23/2014 |
Exposure Tracking Model Ranking |
Initial ranking with ETM completed for source area id: 79715 name: Miscellaneous Fuel Releases |
Mitzi Read |
| 6/30/2015 |
Site Characterization Report Approved |
On this date, ADEC received the Revised 2015 Dietrich Camp Assessment Work Plan submitted by SLR and dated June 2015. |
Grant Lidren |
| 3/11/2016 |
Site Characterization Report Approved |
On this date ADEC received the Dietrich Camp Assessment Report Dalton Highway Milepost 210 submitted by SLR and dated February 2016. A total of 63 soil borings were advanced to characterize the pad for potential reuse of gravel for DOT Dalton highway improvements. The locations of the borings included: at eight historical fuel storage locations, at the two DOT contaminated test holes discovered in 2012, and at nodes of a 177’ by 177’ grid. Additional borings were stepped out to characterize newly discovered contamination encountered at the southern edge to the pad. Based off field screening and groundwater interface, at least one analytical soil sample was collected from 22 of the 63 borings for a total of 34 soil samples. Contamination above cleanup levels was found at the southern portion of the pad in the subsurface within 2 feet of the groundwater interface. Groundwater was encountered at depths of 3.4 to 10.3 feet bgs throughout the pad. Twelve out of the 34 soil samples collected contained contaminant concentrations above method two cleanup levels with DRO up to 12,400 mg/kg, RRO up to 17,100 mg/kg, 1-methylnapthalene up to 12.6 mg/kg and 2-methylnapthalene up to 12.1 mg/kg. Contaminant concentrations above cleanup levels were not detected in surface soils. (note: at the north end of the pad at the diesel storage area, boring B2 contained DRO at 239 mg/kg (above the method one cleanup level of 200 mg/kg) with a PID head space of 7.3 ppm from a sample collected 0 to 1 ft. bgs. Additionally, adjacent borings D3 and D4 contained head space readings of 5.2 ppm (3 to 4 ft. bgs) and 2.7 ppm (1 to 2 ft. bgs) respectively). Analytical soil samples were not collected from D3 or D4. |
Grant Lidren |
| 6/6/2018 |
Update or Other Action |
Email correspondence with DOT on this date. DOT does not plan to use Dietrich pad gravel for road work but, may in the future. If this is the case, ADEC must receive a gravel handling plan prior to field activities for ADEC approval in accordance with 18 AAC 75.325 Site Cleanup Rules.
|
Grant Lidren |
| 7/30/2018 |
Site Visit |
On this date, ADEC visited site. A DOT camp was present and gravel was being mined for Dalton Hwy roadwork. According to DOT, the mining areas were located so that the DOT would not be mining within the contaminated areas identified in the 2016 Final Dietrich Camp Assessment Report. ADEC was not notified prior to land disturbing field activities. |
Grant Lidren |
| 7/5/2019 |
Site Characterization Workplan Approved |
On this date, ADEC received the Dietrich Camp Monitoring Well Installation Work Plan Revised submitted by SLR and dated July 5, 2019. Two borings will be advanced and completed as monitoring wells in 2021. Soil and groundwater samples will be collected. |
Grant Lidren |
| 2/26/2021 |
Document, Report, or Work plan Review - other |
ADEC staff reviewed and approved the 2019 work plan to install two monitoring wells and collect samples just off of the camp pad to check groundwater flowing toward the dredge pond and Dietrich River for contaminants of concern. |
Laura Jacobs |
| 8/2/2022 |
Document, Report, or Work plan Review - other |
The 2021 well installation and monitoring report was reviewed and approved. The 2022 proposed work plan was approved. DEC requests that the RP delineate the remaining groundwater contamination resulting from the two identified areas with elevated hydrocarbon levels in soils that were found in 2014. |
Laura Jacobs |
| 6/23/2023 |
Document, Report, or Work plan Review - other |
The groundwater and surface water sampling report, received December 7, 2022 was reviewed and approved. Groundwater samples collected from the two monitoring wells resulted in detection of hydrocarbons but all below DEC cleanup levels. The concentration of naphthalene found in MW-1 decreased from a level above the DEC groundwater cleanup level in 2021 to below that concentration in 2022. Diesel range organics (DRO) was the only petroleum compound present in the sample collected from MW-2 but was well below the groundwater cleanup level. The surface water sample result from the gravel pit pond south of the pad had polycyclic aromatic hydrocarbons (PAHs) detected at low levels well below the DEC Alaska Water Quality Standard (AWQS). |
Laura Jacobs |
| 6/23/2023 |
Document, Report, or Work plan Review - other |
DEC approved the 2023 Dietrich Camp Groundwater Monitoring Work Plan for continuing the groundwater and surface water sampling event at the site to ensure remaining petroleum contamination is not migrating to the Dietrich River. |
Laura Jacobs |
| 7/30/2024 |
Document, Report, or Work plan Review - other |
The 2023 Groundwater and Surface Water Sampling report was received December 29, 2023. Two groundwater monitoring locations and two surface water locations were sampled for petroleum contaminants that remain in the gravel pad from historical releases. Groundwater sample results indicate that contaminants are present at wells MW-1 and MW-2 at concentrations below the Table C. Groundwater Cleanup Levels. Surface water sample results included detections of Diesel Range Organics (DRO) at low-level and qualified values, indicating some migration of DRO from groundwater to the surface water impoundment south of MW-1. The report was approved with the request that future coordination occur to address this off-pad migration. |
Laura Jacobs |
| 7/30/2024 |
Document, Report, or Work plan Review - other |
The 2024 Dietrich Camp Groundwater Monitoring Work Plan was received on April 23, 2024 and reviewed by staff. The proposed 2024 work includes sample collection from monitoring wells MW-1 and MW-2 and collection of surface water samples directly downgradient from the two monitoring well locations. Groundwater samples will be analyzed for gasoline range organics (GRO), diesel range organics (DRO), residual range organics (RRO), polynuclear aromatic hydrocarbons (PAHs), and petroleum-related volatile organic compounds (PVOCs). Surface water samples will be analyzed for DRO, PVOCs, and PAHs to calculate total aromatic hydrocarbons (TAH) and total aqueous hydrocarbons (TAqH). The work plan was approved. |
Laura Jacobs |
