| Action Date |
Action |
Description |
DEC Staff |
| 5/2/2007 |
Site Characterization Report Approved |
Received COTU North 2006 Monitoring Well Sample Results. This is the first monitoring event conducted at the COTU NORTH site since 1992. Of the original 29 wells installed in this area, 9 were destroyed as of 1992, 10 were not located in 2006 and are presumed destroyed, and 4 of the 10 that were located were too badly damaged to be sampled resulting in groundwater sample collection from 6 wells (C8, C9, C20, C21, C22, and C26). Sheen was observed on purge water from wells C9, C20 C21, and C26 and sampling results indicated exceedances of cleanup levels in each of the six wells except C8. The free product sumps were also checked and while moderate to heavy sheen was present, free product was not present. |
Bill O'Connell |
| 5/2/2007 |
Site Added to Database |
Site added to the database.
(Date adjusted from 7/9/2008 for report/query consistency.(Reese)) |
Mitzi Read |
| 7/19/2007 |
Update or Other Action |
Received 2007 water quality monitoring work plan for COTU North and COTU South. At COTU North, up to nine soil borings will be advanced and completed as monitoring wells to replace wells that were lost or damaged. Two well points will be installed by hand north of the site near the treatment pond, and two surface water locations will be sampled. At COTU South, 9 monitoring wells and 8 surface water locations will be sampled. |
Bill O'Connell |
| 7/10/2008 |
Site Characterization Report Approved |
2007 monitoring report received for COTU North. Nine boreholes were advanced using a direct push rig, sampled, and completed as monitoring wells. Six wellpoints were also installed along the northern berm of the gravel pad and surface water samples were collected from monitoring points established in 2007. Subsurface soil samples collected from boreholes contained DRO up to 18,200 mg/kg at 2.5-3.5 feet bgs in borehole 07-B3, however the next highest sample had 2,030mg/kg DRO. Benzene was detected up to 2.86 mg/kg and GRO up to 315 mg/kg. Active layer water samples collected from monitoring wells and well points contained DRO, GRO, or benzene above Table C cleanup levels in 13 of the 15 samples collected with DRO up to 54 mg/l in well point C20 and benzene up to 7.34 mg/l in MW-2. Surface water samples exceeded TAH (BTEX) at 3 of the four locations. |
Bill O'Connell |
| 7/10/2008 |
Exposure Tracking Model Ranking |
Initial ranking with ETM completed. |
Bill O'Connell |
| 8/12/2008 |
Site Characterization Workplan Approved |
Work plan received for additional characterization at COTU north. Surface water samples will be collected from 4 existing surface water monitoring locations and four additional monitoring locations will be established and sampled, three in the area known as Impoundment 1 and one in the sewage treatment lagoon north of the site. 16 sediment samples will be collected from impounded areas and 4 hand-driven well points will be installed. Supra-permafrost water samples will be collected from the new well points and also from 21 existing wells and well points. Samples will be analyzed for DRO/RRO, GRO (except surface water), VOCs , and PAHs |
Bill O'Connell |
| 5/20/2009 |
Document, Report, or Work plan Review - other |
Reviewed COTU North 2008 RI Report. Four subsurface soil samples were collected, four hand driven wellpoints were installed and sampled, and active layer water samples were collected from 13 existing monitoring wells. Eight surface water samples and 16 sediment samples were collected from surface water bodies adjacent to the pad. Soil samples did not contain contaminants above the most stringent ADEC cleanup level. Active layer water samples contained DRO, GRO, and BTEX above Table C groundwater cleanup levels in most of the wells sampled with the following maximum concentrations: DRO at 141 mg/l in well 07-MW1; GRO at 34.5 mg/l in well C-22; and benzene at 4.2 mg/l at well 07-MW1. PAHs were not detected above Table C cleanup levels. Sheen was noted on active layer water in well 07-MW3. Surface water samples exceeded AWQS for TAH in 7 of the 8 samples due to benzene which was detected in all 7 samples up to 0.141 mg/l. PAHs were detected at low concentrations however the AWQS for TAqH was also exceeded due to benzene. Sediment samples contained DRO up to 2,870 mg/kg at location SED-16, and benzene up to 15 mg/kg at SED-12. Compared to previous years monitoring data, contaminant concentration is active layer water have increased downgradient of the source area and decrease upgradient and cross gradient. Free product was not encountered in monitoring wells in 2008
|
Bill O'Connell |
| 7/8/2009 |
Document, Report, or Work plan Review - other |
Reviewed 2009 COTU North Water Quality Monitoring Work Plan. Surface water samples will be collected from 6 locations and active layer water samples will be collected from 18 monitoring wells and well points. |
Bill O'Connell |
| 6/29/2010 |
Document, Report, or Work plan Review - other |
Reviewed 2009 monitoring report form COTU North. Surface water samples were collected from 6 established sampling locations and one new location, SW-9. Pore water samples were collected from 18 monitoring wells. Surface water samples exceeded AWQS for TAH or TAqH at locations SW-1, SW-3, and SW-4, primarily resulting from BTEX concentrations with few PAHs detected. Pore water samples collected from monitoring wells contained contaminants above groundwater cleanup levels in 16 of the 18 wells, with GRO detected up to 99.9 mg/l in well 07-MW-2, benzene up to 10.8 mg/l in the same well, and DRO up to 80.0 mg/l in well 07-MW-3. The report concludes pore water flow is to the northwest and the plume is generally stable. Sheen was not generated in the surface water impoundments where surface water samples were collected. |
Bill O'Connell |
| 8/3/2010 |
Document, Report, or Work plan Review - other |
Reviewed 2010 COTU North Water Quality Monitoring Work Plan. Six surface water samples will be collected from established monitoring locations and 18 pore water samples will be collected from monitoring wells at the site. |
Bill O'Connell |
| 6/22/2011 |
Document, Report, or Work plan Review - other |
Reviewed 2010 monitoring report for COTU North. Six surface water samples and 18 pore water samples were collected from established monitoring locations at the site. Hydrocarbon sheen was generated at two of the surface water sampling locations SW-2 and SW-9. GRO was detected in three of the surface water samples at concentrations up to 1.74 mg/l and DRO was detected at four locations up to 5.18 mg/l. TAH and TAqH concentrations were exceeded at SW-1, -2, -3, and -4. Petroleum hydrocarbons were detected at every pore water sampling location with DRO detected up to 24.4 mg/l at 07-MW-03, GRO detected up to 121 mg/l at 07-MW-01, and benzene detected up to 8.0 mg/l at 07-MW-02. Groundwater flow is to the northwest towards the sewage treatment lagoon. Sampling indicates there is a consistent plume of hydrocarbon impacted pore water in the pad across the entire site. Contaminant concentrations were generally consistent with previous data, however marked increases in contaminant concentrations were noted in several wells. |
Bill O'Connell |
| 6/22/2011 |
Document, Report, or Work plan Review - other |
Reviewed 2010 monitoring report for COTU North. Six surface water samples and 18 pore water samples were collected from established monitoring locations at the site. Hydrocarbon sheen was generated at two of the surface water sampling locations SW-2 and SW-9. GRO was detected in three of the surface water samples at concentrations up to 1.74 mg/l and DRO was detected at four locations up to 5.18 mg/l. TAH and TAqH concentrations were exceeded at SW-1, -2, -3, and -4. Petroleum hydrocarbons were detected at every pore water sampling location with DRO detected up to 24.4 mg/l at 07-MW-03, GRO detected up to 121 mg/l at 07-MW-01, and benzene detected up to 8.0 mg/l at 07-MW-02. Groundwater flow is to the northwest towards the sewage treatment lagoon. Sampling indicates there is a consistent plume of hydrocarbon impacted pore water in the pad across the entire site. Contaminant concentrations were generally consistent with previous data, however marked increases in contaminant concentrations were noted in several wells. |
Bill O'Connell |
| 7/20/2011 |
Document, Report, or Work plan Review - other |
Reviewed 2011 work plan for COTU North. Porewater samples will be collected from 18 monitoring wells and analyzed for DRO, GRO, and BTEX. Surface water samples will be collected at 6 established monitoring locations and analyzed for DRO, GRO, BTEX, and PAHs. |
Bill O'Connell |
| 7/31/2012 |
Document, Report, or Work plan Review - other |
Reviewed 2012 work plan for water quality monitoring at COTU North. Pore water samples will be collected from 25 wells and surface water samples will be collected from 6 established monitoring locations. |
Bill O'Connell |
| 8/16/2012 |
Document, Report, or Work plan Review - other |
Reviewed 2011 monitoring report for COTU North. Surface water samples were collected from 6 established monitoring locations and pore water samples were collected from 18 wells. Surface water samples exceeded AWQS for TAH and/or TAqH at 4 locations, SW-1 to SW-4, typically as a result of the BTEX concentrations. The locations of these exceedances are within impounded water bodies on the gravel pad. Pore water samples contained DRO up to 22.4 mg/l in well C-22, GRO up to 96.4 mg/l in well 07-MW-02 and benzene up to 6.66 mg/l in the same well. These results are consistent with previous results and a Mann-Kendall trend analyses of pore water results indicates a stable trend in contaminant concentrations at most wells. |
Bill O'Connell |
| 5/10/2013 |
Update or Other Action |
Discrete areas of hydrocarbon contamination were noted in soil in the immediate vicinity of this site during installation of a gas line in 2012. |
Bill O'Connell |
| 6/19/2013 |
Document, Report, or Work plan Review - other |
Date of receipt of 2012 Monitoring report reviewed 10/2/13. Pore water (active-layer) and surface water were sampled in August 2012. Pore water sampled from 14 monitoring wells and 10 well points was analyzed for BTEX, GRO, and DRO. Six surface water locations were sampled and analyzed for GRO, DRO, BTEX, and PAHs. Flow direction of pore water generally trends in a northerly and westerly direction towards the lake, both for this event and historically. Analytical results indicate either a stable plume or no trend, like previous events. Four locations exceed TAH and two of these exceed TAqH, which is also similar to past results. |
Keather McLoone |
| 8/8/2013 |
Document, Report, or Work plan Review - other |
Reviewed COTU North water quality monitoring work plan. Pore water samples will be collected from 18 wells, surface water samples will be collected from six established monitoring locations and field observations will be recorded. |
Bill O'Connell |
| 3/28/2014 |
Document, Report, or Work plan Review - other |
Date of receipt of 2013 RCRA Annual Report. Appendix A addresses work conducted at SWMU Project Groups to Fulfill Other Obligations which includes documenting that water sampling was conducted at this site in August 2013. Results are to be reported elsewhere. Ten monitoring wells, eight well points, and six surface water locations were sampled for field measurements and GRO, DRO, and BTEX. Surface water was also sampled for PAHs. |
Keather McLoone |
| 6/5/2014 |
Document, Report, or Work plan Review - other |
Date of receipt of 2013 Monitoring Report. Porewater was sampled at twenty locations for GRO/DRO and BTEX. Surface water was sampled at six locations for GRO/DRO, BTEX and PAH. Mann-Kendall only run on two of four constituents it has been run on in past. Otherwise, information suggests plume stability. |
Keather McLoone |
| 7/30/2014 |
Document, Report, or Work plan Review - other |
Date of receipt of hardcopy (email copy on 7/25/14) of Water Quality Monitoring Work Plan. Nineteen wells and six surface water locations will be sampled (in addition to 3 duplicates and 2 MS/MSDs) for GRO/DRO and BTEX. PAH samples will also be collected for surface water locations. It should be noted that there are twenty well locations and seven surface water locations listed in Table 4. |
Keather McLoone |
| 9/4/2014 |
Site Visit |
|
Keather McLoone |
| 5/28/2015 |
Document, Report, or Work plan Review - other |
Date of cover letter accompanying Crude Oil Topping Unit – North, 2014 Contaminated Sites Monitoring Report dated June 2015. 2014 Sampling included ten wells, nine well points, and six surface water locations. ADEC comment letter dated June 26, 2015 requested a revised report to include trend analyses of DRO or that sampling at all the former locations be conducted (amongst other comments). |
Keather McLoone |
| 7/29/2015 |
Document, Report, or Work plan Review - other |
Date on Transmittal of the 2015 Contaminated Sites Water Quality Monitoring Workplan for D Pad, Service City, COTU North, COTU South, BOC Bulk Fuel Facility Utilidor, DSM Shop, PBOC Generator, MCC Fuel Island. As of 10/15/15 an approval letter hadn't been sent because ERM/BP had not yet provided the 2014 COTU South report although it has been reportedly just about ready for 2 months. |
Keather McLoone |
| 7/31/2015 |
Document, Report, or Work plan Review - other |
Date of receipt of Revised 2014 Contaminated Sites Monitoring Report, Crude Oil Topping Unit - North. This document was revised to include DRO in the trend analysis. ADEC comment letter sent 9/1/15. |
Keather McLoone |
| 8/9/2016 |
Document, Report, or Work plan Review - other |
Reviewed the 2016 Contaminated Sites Soil & Water Quality Monitoring Work Plan, dated August 2016. Proposed activities mainly consist of monitoring well sampling, surface water sampling, and surface soil sampling. |
Joshua Barsis |
| 9/19/2016 |
Document, Report, or Work plan Review - other |
Reviewed two documents; 2015 Contaminated Sites Monitoring Report Crude Oil Topping Unit – North and 2015 Contaminated Sites Monitoring Report D Pad, both dated August 2016. 2016 had been collected before the 2015 reports were received. In recent phone conversations, several concerns were discussed and will be addressed in the 2016 reports. Some of those concerns included sampling frequency, groundwater flow/divides, historical information, and delineation. |
Joshua Barsis |
| 5/30/2017 |
Document, Report, or Work plan Review - other |
Reviewed the 2016 Contaminated Sites Monitoring Report and 2017 Work Plan, dated April 2017 for the BPX Crude Oil Topping Unit North site. This document includes a description of the 2016 field effort completed, along with a work plan for 2017 activities.
Field activities were completed on August 19 and 20, 2016 and generally consisted of surface water and pad porewater monitoring. Analytical samples were collected from 24 monitoring wells and well points (20 of which are considered closely connected with surface water), and from 6 surface water locations (SW-1 through SW-4, SW-8 and SW-9). All samples were submitted for laboratory analysis of gasoline range organics (GRO), diesel range organics (DRO), and benzene, toluene, ethylbenzene, and xylenes (BTEX). In addition, the samples collected from surface water were also analyzed for polycyclic aromatic hydrocarbons (PAHs). Groundwater flow direction and gradient historically vary across the site, but generally flows in a northerly direction at a gradient ranging between 0.018 and 0.050 feet per foot.
Analytical results showed that Surface Water Samples SW-1, SW-2, SW-3, and SW-4 exceeded the Alaska Water Quality Standard (AWQS) for total aromatic hydrocarbons (TAH) and total aqueous hydrocarbons (TAqH). Results from the monitoring wells and well points varied, however most of the samples had contaminant results in excess of their applicable standard; either AWQS or Table C. In general, contamination is not fully defined.
Activities propped for the 2017 field season generally consist of continuing surface water and pad porewater monitoring, but also includes provisions to install up to four additional pad porewater monitoring wells.
ADEC requested a revised report/work plan by July 1, 2017 to address several issues.
The final report/work plan, dated July 2017, was received on August 1, 2017. |
Joshua Barsis |
| 7/17/2018 |
Document, Report, or Work plan Review - other |
Reviewed the 2017 Contaminated Sites Monitoring Report and 2018 Work Plan, dated July 2018 for the BPX Crude Oil Topping Unit North site. This document includes a description of the field effort completed in August 2017, along with a work plan for 2018 activities.
Activities completed in 2017 generally consisted of biennial surface water and porewater monitoring, but also included installation of two additional soil boring that were completed as monitoring wells. Analytical samples were collected from 17 monitoring wells and well points (11 of which are considered hydrologically connected to surface water) including from the two newly installed wells, and from eight surface water locations. Although planned, an analytical water sample was not collected from Well Point 07-WP-5 because standing product was noted in the well. Groundwater flow direction was noted to flow north-northwest at a gradient of 0.025 feet per foot; however with the caveat that the groundwater gradient at this site has historically varied by an order of magnitude.
A summary of results for this site indicate that there is contamination in the porewater and surface water, however the extent of contamination is relatively delineated, except in one area to the east. Proposed 2018 activities include continued groundwater and surface water monitoring, and installation of two additional soil borings that will be completed as monitoring wells.
|
Joshua Barsis |
| 8/12/2019 |
Document, Report, or Work plan Review - other |
Reviewed the 2018 Contaminated Sites Monitoring Report and 2019 Work Plan, dated July 18, 2019 for the BPX Crude Oil Topping Unit North site. This document includes a description of the field effort completed in August 2018, along with a work plan for 2019 activities. Activities completed in 2018 generally consisted of biennial surface water and porewater monitoring, but also included installation of two additional soil boring that were completed as monitoring wells (18-MW-10 and 18-MW-13). Analytical samples were collected from 27 monitoring wells and well points (20 of which are considered hydrologically connected to surface water), and from 7 surface water locations. Proposed 2018 activities include continued groundwater and surface water monitoring, and installation of additional soil borings that will be completed as monitoring wells. |
Joshua Barsis |
| 11/14/2023 |
Document, Report, or Work plan Review - other |
Reviewed the 2022 Contaminated Site Monitoring Report and Proposed Work Plan, dated February 28, 2023. The report details porewater and surface water monitoring conducted in July 2022. Laboratory analytical samples were collected from four surface water sample locations and five porewater monitoring well points.
Surface water analytical results revealed one or more BTEX constituents in all four locations, with benzene up to 43.3 µg/L, two locations exceeded the AWQS of 5 µg/L. Porewater analytical results revealed concentrations of DRO above the groundwater cleanup level (CUL) in one location at 6,190 µg/L. Concentrations of one or more BTEX constituents were detected in three of the five porewater well points, with benzene exceeding the AWQS and groundwater CUL at two of the well points, up to 562 µg/L. Ethylbenzene and total xylenes exceeded the groundwater CUL at one location with concentrations of 71.1 µg/L and 525 µg/L, respectively. Various VOCs were also detected above groundwater CULs in two locations. Both the TAH and TAqH were exceeded in three of the five locations. M-K statistical analyses exhibited increasing trends for GRO and total xylenes in one porewater well point and decreasing trends for GRO and total xylenes in another well point. The work plan portion of the report proposes repeating the same monitoring activities in 2023. ADEC has reviewed the 2022 report and 2023 work plan and it is now approved.
|
Andrea Carlson |
