A05_-_PWS_-_Attachment__3_-_25241_2013_12_01_drum_investigation_rprt.pdf

The world's leading sustainability consultancy

Trench Installation for Preliminary Drum Assessment Report

Napaskiak, Alaska

Prepared for ECI/Hyer Architecture & Interiors

December 2013

Prepared By: ______________________________________ Ryan Burich Environmental Scientist

Reviewed By: ______________________________________ Stephen Witzmann, P.E.

Project Manger

ERM Alaska, Inc.

825 West 8th Avenue

Anchorage, Alaska 99501 T: (907) 258-4880 F: (907) 258-4033

- Page Intentionally Left Blank -

Trench Installation for Preliminary Drum Assessment Report ECI/Hyer Architecture and Interiors

ERM i 12/18/2013

TABLE OF CONTENTS

ACRONYMS AND ABBREVIATIONS ................................................................................. iii

EXECUTIVE SUMMARY........................................................................................................... v

1. INTRODUCTION

1.1. Background

1.1.1. Site Information

1.1.2. Previous Assessment and Remediation Events

1.2. Project Objectives

1.3. Contaminants of Concern and Regulatory Framework

2. FIELD ACTIVITIES

2.1. Area Determination

2.2. Excavation

2.2.1. West to East Trench

2.2.2. North to South Trench

2.2.3. Additional Trenches

2.3. Drum Assessment

2.4. Soil Sampling

2.5. Investigation-Derived Waste Management

3. ANALYTICAL RESULTS

3.1. Laboratory Analytical Results

3.1.1. Analytical Methods

3.1.2. Soil Sampling Analytical Results

4. QUALITY ASSURANCE/QUALITY CONTROL

4.1. Detection Limits and Reporting Limits

5. CONCEPTUAL SITE MODEL

5.1. Receptor Profile

5.2. Exposure Pathways

6. CONCLUSIONS AND RECOMMENDATIONS

6.1. Conclusions

6.2. Recommendations

7. REFERENCES

TABLES

1: Test Pit Analytical Results for Area D 2: LSKD Drum Assessment PID Screenings 3: Drum COPC and Analytical Methods 4: Potential Exposure Pathways

ERM ii 12/18/2013

FIGURES

1: Site Location Map 2: Site Detail 3: Trench Excavation Locations 4: Trench and Drum Locations

APPENDICES

A: Historical Drawings B: Photograph Log C: Field Notes D: Analytical Data Tables E: Laboratory Analytical Report F: Quality Assurance Review and ADEC Checklist G: Conceptual Site Model

ERM iii 12/18/2013

ACRONYMS AND ABBREVIATIONS

°C ............................... degrees Celsius °F ................................ degrees Fahrenheit AAC ........................... Alaska Administrative Code ADEC ........................ Alaska Department of Environmental Conservation AST ............................ aboveground storage tank BTEX .......................... benzene, toluene, ethylbenzene, and toluene bgs ............................. below ground surface BIA ............................. Bureau of Indian Affairs COC ........................... chain of custody CSM ........................... Conceptual Site Model Cruz ........................... Cruz Construction, Inc.

COPC ......................... contaminant of potential concern DRO ........................... diesel-range organics ECI/Hyer .................. ECI/Hyer Architecture & Interiors EPA ............................ U.S. Environmental Protection Agency ERM ........................... ERM Alaska, Inc.

ft ................................. feet g ................................. gram GRO ........................... gasoline-range organics HAZWOPER ............. Hazardous Waste Operations and Emergency Response LKSD ......................... Lower Kuskokwim School District mg/kg ....................... milligrams per kilogram OASIS ........................ OASIS Environmental, Inc.

PAH ........................... polycyclic aromatic hydrocarbons PCB ............................ polychlorinated biphenyl PID ............................. photoionization detector PPE ............................ personal protective equipment QA/QC ..................... quality assurance/quality control RRO ........................... residual-range organics SSC ............................. subsurface clearance SGS ............................ SGS Environmental Services, Inc.

SVOC ......................... semi-volatile organic compound VOC ........................... volatile organic compound

ERM iv 12/18/2013

ERM v 12/18/2013

EXECUTIVE SUMMARY

ECI/Hyer Architecture & Interiors has tasked ERM Alaska, Inc., formerly OASIS Environmental, Inc., with completion of tasks associated with a preliminary assessment of possible buried drums at the former Bureau of Indian Affairs school site in Napaskiak, Alaska. The suspected drum site is within the proposed footprint of a grass play field, located adjacent to the new school building being designed for the Lower Kuskokwim School District (LKSD). This project was designed to help determine the presence and density of drums in the potential drum pit.

In accordance with the Trench Installation for Preliminary Drum Assessment Work Plan, two trenches, each 50 feet (ft) in length and up to 8 ft deep, were to be excavated to assess for the possible presence of drums. During excavation of these trenches, drums were encountered. All drums encountered appear to have been empty and punctured prior to burial. To better define the extent of the drum pit, the extent of the trenches was modified based on the locations where drums were found. Additional trenches and test pits were excavated to determine the limits of the buried drums.

In accordance with the work plan, analytical samples were collected to assess contaminants that have been released to site soils. The area was known to be impacted by fuel contamination at concentrations above the migration to groundwater cleanup level, but below cleanup levels protective of direct contact and outdoor inhalation. Low levels of fuel contamination were found, but visual evidence and analytical results suggest that the drums were empty when buried.

ERM vi 12/18/2013

ERM 1 12/18/2013

1. INTRODUCTION

This report describes the site background, project objectives, contaminants of concern, completed field activities, soil sampling analytical results, quality assurance/quality control information, and the conceptual site model.

1.1. Background

1.1.1. Site Information

The project site is located in Napaskiak, a small village situated in southwestern Alaska on the Yukon-Kuskokwim Delta. It is positioned on the south bank of the Kuskokwim River, at the mouth of Napaskiak Slough, approximately 7 miles downriver from Bethel.

The village lies at approximately 60.708060° north latitude and 161.766110° west longitude; section 08, township 007 north, range 071 west (T007N, R071W), Seward Meridian and is included in the Bethel Recording District. The village area encompasses approximately 3.5 square miles of land and 0.4 square miles of water. Napaskiak is strongly influenced by storms and patterns in the Bering Sea and also by inland continental weather. Average annual precipitation is 16 inches, including 50 inches of snowfall. Summer temperatures range from 42 to 62 degrees Fahrenheit (ºF), and winter temperatures range from -2 to 19˚ F (Alaska Community Database Community Information Summaries 2009) (Figure 1).

The village is located in the floodplain of the Kuskokwim River which consists of fluvial and floodplain deposits. Groundwater depth may vary seasonally, but is assumed to be approximately 7 to 9 feet (ft) below ground surface (bgs). A field team excavating test pits at the site in 2011 reported water seeping into the test pits at depths that generally ranged from 7 to 7.5 ft bgs (Alaska Department of Environmental Conservation [ADEC] 2012).

The former Bureau of Indian Affairs (BIA) school site is located in the western half of the village and approximately 150 ft south of the Napaskiak Slough (Figure 2).The BIA school was replaced in 1980 by the Z. John Williams Memorial School which is located approximately 350 ft southeast of the former BIA school site. The Z. John Williams Memorial School is scheduled for replacement, with ECI/Hyer Architecture & Interiors (ECI/Hyer) as the acting architectural firm. The former BIA school site is currently the planned location for the new school. There are presently two abandoned buildings on the site, including the former BIA school building (PK08) and the housing building (PK09/PK15). Two buildings (PK06 and PK07) were demolished in 2012 (Figure 2).

In October 2012, the Lower Kuskokwim School District (LKSD) provided ERM Alaska, Inc. (ERM), formerly OASIS Environmental, Inc. (OASIS), with photographs of a drawing dated March 1970 from the Department of the Interior, Bureau of Indian Affairs, Division of Plant Design and Construction. Notations include “Napaskiak School, ERM 2 12/18/2013

Napaskiak, Alaska, Kindergarten: Classroom and Quarters”. This drawing has an annotation “Existing Backfilled Pit – Verify”.

A second drawing is dated October 23, 1972 and titled Napaskiak, Alaska, Water & Waste Treatment. This drawing shows a “pit filled with 55 gal. drums” in the same area as in the 1970 drawing. The drawing contains a note to “obtain fill from suitable remote area (not crest of hill) and backfill pit presently containing 55 gallon drums.” Prior to the assessment it was unclear whether or not the drums were still present and, if present, whether they were full or empty, intact or crushed when they were buried. When considered together, the two drawings seem to infer that the BIA had a plan to cover the drums where they were located in the pit. The drawings are presented in Appendix A.

1.1.2. Previous Assessment and Remediation Events

Previous assessment and remediation events have been conducted in this area. These efforts include a site reconnaissance in 2001, a site characterization in 2011, and hand auger boring and landfarming activities in 2012. Each is discussed below.

1.1.2.1. 2001 Site Reconnaissance

In 2001, OASIS conducted an area-wide reconnaissance of the Napaskiak tank farms (OASIS 2002). Adjacent to the abandoned BIA school and utility building, day tanks were present. The tanks are now gone but cribbing denoted the area where the tanks had existed. An area of stained soil was noted at this location and a sample collected from 3 ft bgs within the stained area had a diesel-range organics (DRO) concentration of 38,900 milligrams per kilogram (mg/kg). Other petroleum constituents were below the ADEC 18 Alaska Administrative Code (AAC) 75.341 Table B1 Method Two - Soil Cleanup Levels. The school’s drinking water well was located about 550 ft southeast of the stained area at the Z. John Williams School (Figure 2).

Three other spill areas were identified in this immediate area. One was to the west of the day tank area and was a release from BIA piping. The second was located southwest of the day tank release at a former containment area; the spill was related to a cracked piping. The third release was a small area from a suspected leaking header valve just north of the utility building. A second former aboveground storage tank containment area was located south of the former school. This area was not sampled.

1.1.2.2. 2011 Site Characterization of Former BIA School Day Tanks

In 2011, site characterization was conducted to assess the site for potential environmental contamination from historical uses, in preparation for construction of the proposed new school. This assessment was documented in the report titled Napaskiak Former BIA School Day Tanks; Site Characterization Report (ADEC 2012a). Among the tasks associated with the site characterization, ERM assessed surface and subsurface soils by digging test pits in four areas of potential concern and collecting soil samples. Samples were analyzed for DRO, residual-range organics (RRO), gasoline-range organics (GRO), ERM 3 12/18/2013 benzene, toluene, ethylbenzene and xylenes (BTEX), and polycyclic aromatic hydrocarbons (PAH).

ERM and their subcontractor used a small excavator to dig a total of 25 test pits in the areas of potential concern (Figure 3). Each area contained test pits with DRO concentrations exceeding the ADEC 18 AAC 75.341 Table B2 Method Two – Petroleum Hydrocarbon Soil Cleanup Level of 250 mg/kg, for migration to groundwater. ERM utilized the soil sample analytical results to delineate the extent of impact in the four areas and designated these areas A, B, C and D. The suspected drum pit is located adjacent to Area D where 5 test pits were excavated (Figure 3); however, no drums were encountered in any of these test pits. Note that test pit D1 was only excavated to 0.5 ft bgs because of lack of excavator access. Test pits D2 and D3 extended to 8 ft bgs. Soil sample analytical results indicated three of the five tests pits in Area D had DRO levels that exceeded the soil cleanup level for migration to groundwater. All other DRO, RRO, GRO, and BTEX results were below cleanup levels. Table 1 below presents the soil sample analytical results of test pits with DRO concentrations exceeding the soil cleanup level for migration to groundwater.

TABLE 1: TEST PIT ANALYTICAL RESULTS FOR AREA D

Test Pit Depth DRO Results (mg/kg) D1 0.5 ft bgs 26,100

D2 0.5 ft bgs 608

D3 2.0 ft bgs 2,420

1.1.2.3. 2012 Landfarming

Analytical results indicated concentrations of DRO exceeded the ADEC 18 AAC 75.341 Table B2 Method Two – Petroleum Hydrocarbon Soil Cleanup Level of 12,500 and 10,250 mg/kg for the inhalation and ingestion exposure pathways, respectively, in surface soil samples collected in the vicinity of the former school buildings. In-place landfarming was selected as the most feasible method to reduce concentrations of DRO in soil.

Aggressive soil tilling was expected to provide two benefits: reduce contaminant concentrations to below the level at which they are toxic to bacteria (speeding biodegradation) and address potential human health risk via the ingestion and inhalation pathways. An area of stained soil sampled in 2011 contained a DRO concentration of 38,900 mg/kg. Otherwise, the maximum DRO concentration detected at the site in 2011 was 26,100 mg/kg. Fuel concentrations greater than approximately 25,000 mg/kg are considered inhibitory and/or toxic to aerobic bacteria (EPA 2004).

Thus, soil concentrations greater than this threshold tend to decrease only very slowly over time. Aggressive soil tilling may reduce soil concentration to below this threshold, allowing microorganisms capable of degrading petroleum hydrocarbons conditions in which they can survive and thrive. The initial tilling was also expected to reduce average soil concentrations below 10,250 mg/kg, the DRO cleanup standard for the

ERM 4 12/18/2013

ingestion exposure pathway (The inhalation standard is slightly higher at 12,500 mg/kg).

The LKSD constructed two in-place landfarm cells at the site. Thorough tilling of fuel-contaminated soil was performed over the course of eight tilling events during a four week period. Tilling took place to a depth of 18 inches below ground surface (bgs) (OASIS 2013a). After the initial tilling event, baseline samples were collected. Soils were placed on a surface slope of 0.5% towards runoff containment areas. Barriers were constructed 24-inches high surrounding the landfarm cells to prevent contaminant migration. An ERM field scientist remobilized to the site to collect post-treatment composite samples at the end of the treatment season to assess current residual contaminant concentrations. Soil sample analytical results indicated DRO concentrations were 3,098 and 2,964 mg/kg in landfarm cells A and B, respectively. These contaminant concentrations are below levels expected to pose a risk through the ingestion and inhalation exposure pathways. More information about this event is documented in the report titled Napaskiak Remediation Report (OASIS 2013a).

1.1.2.4. 2012 Hand Auger Borings

Staff members from LKSD mobilized to the former BIA school site in October 2012 to perform a preliminary assessment of the potential drum pit. Five hand auger borings were performed. Swing ties were used to locate the center of the potential drum pit, as shown on the historical drawings (Appendix A). The first boring was advanced at the approximate center of the area shown, the other four borings were advanced 7.5 ft away from the first boring, in each of the cardinal directions. The first boring was advanced to 8 ft bgs. The remaining four borings were advanced to 6 ft bgs. Boring locations are shown on Figure 3.

Visual inspection of soil cuttings was performed every foot upon auger removal. Soil samples were collected and field screened using a photoionization detector (PID).

Samples were collected from the first boring at 4 ft bgs, 6 ft bgs, and 8 ft bgs. All borings were reported to have consistent soil types at each depth interval. At 1-2 ft bgs, soil appeared tilled and disturbed with a slight diesel-fuel odor present but no noticeable discoloration. From 2-4 ft bgs, soils were reportedly silty with some clay, dark brown in color, moist, with no odor. From 4-5 ft bgs, soil reportedly had a loose consistency and was composed of decomposing organic material, with a slight hydrocarbon odor present at 5 ft bgs. Fine sands were reported from 6-8 ft bgs, wet, and with a slight hydrocarbon odor. At 8 ft bgs, sand and silts were reported, and were saturated with a strong hydrocarbon odor.

ERM 5 12/18/2013

TABLE 2: LKSD DRUM ASSESSMENT PID SCREENINGS

Location Depth PID Results (parts per million)

Boring 1 (headspace)

4 ft bgs 6.8 6 ft bgs 8.2 8 ft bgs 148.2

Boring 1 (open hole) At surface 57 Boring 2 (open hole) At surface 57 Boring 3 (open hole) At surface Not applicable (Water Present) Boring 4 (open hole) At surface 84 Boring 5 (open hole) At surface 47

During the LKSD’s investigation, no obstructions were encountered, and no drums or metal of any kind was found.

1.2. Project Objectives

The primary objective of this assessment was to assess whether or not drums were buried in the area shown on the historical drawings provided by the LKSD (Appendix A). Tasks associated with this objective included:

• Excavate a pair of trenches, in an “X” formation, over the potential drum disposal area/pit, to determine whether or not drums are present.

• If drums are encountered:

o Determine the extent of the drum disposal area/pit, and estimate the density of drums present.

o Collect and submit soil samples for analysis to characterize potential contamination in the drum disposal area/pit.

1.3. Contaminants of Concern and Regulatory Framework

Due to the potential presence of drums at this site and their unknown contents, ERM conferred with the ADEC to establish a suitable approach to performing the tasks associated with the project objectives. Based on ADEC recommendation, soil samples from the site were to be analyzed for a wide variety of contaminants of potential concern (COPC) if drums were encountered. COPCs typically associated with drum disposal sites in remote locations of Alaska include DRO, RRO, GRO, volatile organic compounds (VOC), semi-volatile organic compounds (SVOC), PAH, polychlorinated biphenyls (PCB), and lead. This selected suite of analytes would be indicative of fuels, lubricating oils, solvents, and/or transformer fluids.

Table 3, shown below, provides analytical methods for each COPC.

ERM 6 12/18/2013

TABLE 3: DRUM COPC AND ANALYTICAL METHODS

COPC Laboratory Method VOC EPA Method SW8260B

SVOC EPA Method SW8270D PAH EPA Method SW8270D-SIM GRO Alaska Method AK101 DRO Alaska Method AK102 RRO Alaska Method AK103 PCB EPA Method SW8082A Lead EPA Method SW6020

Soil sample collection was conducted in accordance with the sampling plan outlined in Section 3.1 of the document titled Trench Installation for Preliminary Drum Assessment Work Plan (OASIS 2013b) and all sampling methodologies were performed as described in the ADEC Draft Field Sampling Guidance (ADEC 2010a).

Personnel working at this site completed 40-hour Hazardous Waste Operations and Emergency Response (HAZWOPER) training and 8-hour annual HAZWOPER refresher training, as applicable, prior to initiating project work. Personnel also obtained a physician’s clearance to wear a respirator, received valid respirator fit test documentation, and acquired a half-face or full-face respirator with organic vapor cartridges.

ERM was instructed to report the release of any drum liquids to the ADEC Prevention and Emergency Response Program (Cob Carlson in Bethel bob.carlson@alaska.gov, 907- 543-3215) on the Oil and Hazardous Substances Spill Notification Form (http://dec.alaska.gov/spar/spillreport.htm), and list the BIA and the Department of the Interior as the responsible party. ERM was also advised to notify Grant Lidren of the ADEC simultaneously. However, no release occurred.

mailto:bob.carlson@alaska.gov http://dec.alaska.gov/spar/spillreport.htm

ERM 7 12/18/2013

2. FIELD ACTIVITIES

This section describes field activities conducted in support of the buried drum pit assessment objectives. ERM personnel provided oversight for drum assessment activities between October 4 and 6, 2013. Cruz Construction, Inc. (Cruz) personnel operated a locally-available backhoe to excavate assessment trenches. SGS Environmental Services, Inc. (SGS), a laboratory approved by ADEC for contaminated sites analysis, provided analytical support. The locations of the trenches, test pits, buried drums, and sample collection points with DRO results are presented on Figure 4. Project site historical plans/drawings are presented in Appendix A. A photographic log is included in Appendix B, and field notes are provided in Appendix C. Appendix D contains a summary of soil sample collection and analyses by date, time, and location.

Table D-1 contains detected analytes only; Table D-2 contains all results.

2.1. Area Determination

Using the historical drawings (Appendix A) and swing-tie measurements off of three points on the eastern end of the abandoned BIA school (building PK08), ERM located the approximate center of the potential drum pit. ERM then measured 25 ft to the east and west of this center point to designate the placement of the initial 50-ft-long assessment trench.

2.2. Excavation

Two, 50-foot-long assessment trenches, each approximately perpendicular to the other in an “X” pattern, were planned for installation in the area overlying the potential drum pit. Figure 4 shows both the planned trench layout and the trenches and excavations that were actually dug. The trenches were excavated to a maximum depth of 8 ft bgs. In areas where drums were encountered, the depth of the excavation was limited by the presence of drums. The upper 4-ft layer of excavated soil was placed on one side of the trench, while the lower 4-ft layer of excavated soil was placed on the other side of the trench. This segregation of materials ensured the deeper potentially-contaminated soil was placed back into the trench before the shallower soil during backfill activities. Cruz personnel coordinated the use of, and operated, a locally-available 331 Bobcat with a backhoe attachment for the trench installations. ERM personnel provided project oversight and ensured the subsurface clearance (SSC) process was completed prior to excavation activities. The SSC process was implemented to avoid contact with subsurface structures and included ensuring a public utility locate was completed, utility-specific information from local, knowledgeable individuals was obtained, historical and current site plans and as-built drawings were researched, and a visual site inspection was conducted.

ERM 8 12/18/2013

2.2.1. West to East Trench

Installation of the first assessment trench was initiated on the western end of the proposed trench location and continued to the east (Appendix B; Photograph 1). The soil horizons were visually analyzed once the maximum depth of 8 ft bgs was initially achieved (Appendix B; Photograph 3). Damp organic material was recorded from 0 - 1 ft bgs. Damp, grey silt, with some native woody material, was recorded from 1 – 8 ft bgs.

Buried drums were encountered approximately 8 ft east of the trench installation starting point and approximately 2 - 3 ft bgs (Appendix B; Photograph 4). The buried drums extended an additional 22 ft to the east and were consistently 2 - 3 ft bgs. The assessment trench continued an additional 5 ft east of the buried drums and to a depth of 7 ft bgs. Damp organic material was recorded from 0 - 1 ft bgs. Damp, grey silt, with some native woody material, was recorded from 1 – 7 ft bgs. No additional drums or metal debris were encountered in this interval. Based on these field observations, the eastern and western margins of the buried drum pit appeared to be adequately delineated; however, a test pit was excavated to 5 ft bgs at the eastern extent of the proposed trench (approximately 20’ east of the buried drum pit’s eastern margin) to further verify an absence of buried drums. No drums or metal debris were encountered in the test pit. The trench and test pit were backfilled after soil samples were collected and before continuing with the second trench. It should be noted that there was no sign of sheen, hydrocarbon odor, or other contaminant odor during the installation of this assessment trench.

2.2.2. North to South Trench

Based on the locations of the eastern and western margins of the buried drum pit, as verified by the initial east - west trending assessment trench, a second north – south trending trench was installed perpendicular to the initial trench, in the assumed center of the buried drum pit (Figure 4). The purpose of this second trench was to delineate the northern and southern margins of the buried drum pit.

Installation of the second assessment trench was initiated on the northern end of the proposed trench location and continued to the south (Figure 4). Buried drums were encountered approximately 11 ft south of the trench installation starting point and approximately 1.5 - 2 ft bgs (Appendix B; Photograph 5). The buried drums extended an additional 16 ft to the south and were consistently 1.5 – 3 ft bgs. The assessment trench continued an additional 2 ft south of the buried drums and to a depth of 7 ft bgs. No additional drums or metal debris were encountered in this interval. Based on these field observations, the northern and southern margins of the buried drum pit appeared to be adequately delineated; however, three test pits were excavated to 5 ft bgs at 5, 13, and 23 ft south of the buried drum pit’s southern margin to further verify an absence of buried drums (Appendix B; Photographs 11 and 12). No additional drums or metal debris were encountered in the three test pits. The soil horizons were visually analyzed in each pit.

Damp organic material was recorded from 0 - 1 ft bgs. Damp, grey silt, with some native woody material, was recorded from 1 – 5 ft bgs. The trench and test pits were backfilled

ERM 9 12/18/2013

after soil samples were collected (Appendix B; Photograph 13). It should be noted that there was no sign of sheen, hydrocarbon odor, or other contaminant odor during the installation of this assessment trench or the associated test pits.

2.2.3. Additional Trenches

Four small additional trenches were installed to delineate the northwestern, northeastern, southwestern, and southeastern margin of the buried drum pit (Figure 4).

The trenches were initiated outside of the assumed perimeter of, and commenced in a direction toward the buried drum pit until buried drums were encountered. The trenches ranged from approximately 3 – 7 ft in length and were excavated to approximately 5 ft bgs.

2.3. Drum Assessment

The buried drum pit is located below a portion of the eastern half of the currently-fenced-in landfarm (Cell A) and is an estimated 16 ft wide (north to south) and 22 ft long (east to west). The cluster of drums within the pit appears to be a single layer of 55-gallon steel drums lying on their sides and buried beneath approximately 1.5 to 3 ft of soil. All of the drums encountered appear to have had holes cut in them and the bungs removed prior to burial (Appendix B; Photographs 6 and 7). Most of the drums appeared fairly intact and were empty; however, some were rusted and/or crushed and contained small amounts of accumulated rainwater. There was no sign of sheen, hydrocarbon odor, or other contaminant odor in the area of buried drums. Some of the intact drums contained the markings “MONA LISA.” Project Mona Lisa refers to a military program that supplied facilities (particularly Aircraft Control and Warning sites) in Alaska. The number 62 may refer to the year 1962 (Appendix B; Photograph 10). The Mona Lisa project began in 1953, and was renamed Cool Barge in 1966. This information provides some idea as to when the drums were originally shipped to Alaska; however, the drums may have been reused and changed hands before they were disposed of. The approximate perimeter of the buried drum pit was marked with yellow flagging prior to departing the site (Appendix B; Photograph 14).

2.4. Soil Sampling

Soil samples were collected from five locations within the drum pit assessment trenches (and one test pit) to characterize potential soil contamination. Two of the samples (S-02 and S-04) were collected from trench locations within the buried drum pit area and proximal to buried drums. These two samples were collected just below the layer containing the drums. Three of the samples (S-01, S-03, and S-05) were collected from trench and test pit locations outside of the buried drum pit area. The samples were collected from depths ranging from 3 to 7 ft bgs.

ERM personnel directed the excavator operator to scrape a bucket load of soil from the selected depth and collected the sample from undisturbed soil at the center of the bucket. The excavator bucket was cleaned prior to each sampling location using dry

ERM 10 12/18/2013

decontamination procedures. New, unused stainless steel sample scoops were used for each sample. Soil samples were transferred into laboratory-provided sample containers;

samples for volatile analysis were preserved with methanol. Sample containers were labeled with field sample identification numbers, the date and times of collection, and analyses requested.

Duplicate samples were collected at a frequency of 10% per method for quality assurance/quality control (QA/QC) purposes. Laboratory-prepared trip blanks accompanied all VOC and GRO samples from the laboratory, to the field, and back to the laboratory.

All samples were stored in a cooler with gel ice, maintaining the required temperature range of 4 degrees Celsius (°C) (within ±2°C). Chain-of-custody (COC) procedures were followed.

Due to the logistical difficulties involved in shipping cargo from Napaskiak to Anchorage, the soil samples were kept in Napaskiak until the project crew departed on October 6, 2013. The samples were transported on the same aircraft chartered for the return trip to Bethel. The samples were then shipped to Anchorage on Era Cargo.

Tables D-1 and D-2 of Appendix D summarize the soil samples collected, locations, requested analyses, and analytical results. Laboratory analytical results are discussed in Section 3.

2.5. Investigation-Derived Waste Management

Soil sampling activities generated the following investigation-derived wastes.

• Excess soil remaining after filling sample jars.

• Used disposable personal protective equipment (PPE) and sampling waste.

Excess soil was returned to the buried drum pit area. PPE and disposable sampling wastes were placed in trash bags and disposed of in Napaskiak’s Class III landfill.

ERM 11 12/18/2013

3. ANALYTICAL RESULTS

This section presents a discussion of the soil sample analytical results. The analytical results along with the regulatory standards used to evaluate the analytical data are presented in Table D-1 and D-2 in Appendix D of this report.

The laboratory analytical report and completed data quality review with ADEC checklist for the sample delivery group are provided in Appendix E and F, respectively.

3.1. Laboratory Analytical Results

3.1.1. Analytical Methods

Soil sample analytical results are summarized in Tables D-1 and D-2 of Appendix D and on Figure 4. Soil samples were submitted to the project laboratory, SGS, in Anchorage, AK, in accordance with standard COC procedures outlined in the work plan. Duplicate samples were collected at a frequency of 10% per method for QA/QC purposes. All samples were preserved and stored at a temperature of 4°C ± 2°C prior to delivery to SGS for laboratory analysis.

Soil samples were analyzed for the following target analytes using the methods specified:

• VOC (EPA Method SW8260B)

• SVOC (EPA Method SW8270 D)

• PAH (EPA Method 8270D - SIM)

• GRO (Alaska Method AK101)

• DRO/RRO (Alaska Method AK 102/103)

• PCB (EPA Method SW8082A)

• Metals – lead only (SW6020)

3.1.2. Soil Sampling Analytical Results

Soil samples were collected from five locations within, and proximal to, the area containing buried, empty drums. Because drums can contain a wide variety of potential contaminants, a wide variety of methods were used to analyze soil samples. In total, each sample was analyzed for 165 contaminants of potential concern. Of these 165 contaminants, 34 were detected. Each result was compared to cleanup levels established in ADEC 18 AAC 75 that are protective of the following exposure pathways: outdoor inhalation, direct contact/ingestion, and migration to groundwater. The sample collected from location SO-2 was the only sample to contain an analyte concentration above an 18 AAC 75 Method Two soil cleanup level. The DRO concentration at this location was 272 mg/kg which exceeded the 250 mg/kg 18 AAC 75.341 Table B2 Method Two – petroleum hydrocarbon soil cleanup level for migration to groundwater.

ERM 12 12/18/2013

DRO concentrations at the remaining four sample locations were below the migration to groundwater cleanup level and ranged from 42.8 to 246 mg/kg. GRO, RRO, and lead, as well as various VOCs, SVOs, and PAHs were also detected in soil samples collected at the site, but were found to be well below the most stringent ADEC Table B1 and B2 Method Two soil cleanup levels for the under 40 inch zone (Table D-1 of Appendix D).

In some cases, contaminants were not detected, but method detection limits and/or method reporting limits exceeded one or more of the cleanup levels. Such data has been highlighted in Table D-2 of Appendix D; however, when the site data and the analytical data are evaluated together, it is evident that the drums were buried empty.

ERM 13 12/18/2013

4. QUALITY ASSURANCE/QUALITY CONTROL

Laboratory QA/QC data associated with the analysis of project samples have been reviewed to evaluate the integrity of the analytical data generated during the October 2013 soil sampling associated with the buried-drum assessment trench installation in Napaskiak, Alaska. Soil samples were shipped to SGS in Anchorage, Alaska and results were reported in one sample delivery group 1135014. Samples were collected, reported, and shipped in general accordance with the ADEC-approved work plan (OASIS 2013b).

All data were reviewed in accordance with appropriate U.S. Environmental Protection Agency (EPA) procedural guidance documents (EPA 2008; 2010) and ADEC regulatory guidance documents (ADEC 2009; 2012b). An ADEC laboratory checklist was completed (ADEC 2010b).

This data review focuses on criteria for the following QA/QC parameters and their effect on the quality of data and usability: sample handling and COC documentation;

holding time compliance; field QA/QC (trip blanks, field duplicate) results; laboratory QA/QC (method blanks, laboratory control samples, surrogates, results and analytical methods; method reporting limits; precision and accuracy; and completeness.

Overall, QA/QC results for this project indicate that the analytical data are acceptable and defensible for project use with the following qualifications:

• GRO was detected in the trip blank. As a result, GRO results in samples 13-NK- 01-SO and 13-NK-05-SO were qualified as not detected (UB).

• The field duplicate relative percent difference for the duplicate pair collected from sample location SO-2 was outside control limits for the following analytes:

DRO, RRO, 1-methylnaphthalene, 2-methylnapthalene, benzo(a)pyrene, benzo(b)fluoranthene, benzo(g,h,i)perylene, chrysene, dibenzo(a,h)anthracene, indeno(1,2,3-cd)pyrene, naphthalene, phenanthrene, and pyrene. Results were qualified as estimated (JD).

• In PAH 8270-SIM analysis, naphthalene was detected in the method blank. The naphthalene result in samples 13-NK-02-SO, 13-NK-03-SO and 13-NK-06-SO was qualified as estimated with a high bias (JB).

• Surrogate 2-fluorobiphenyl percent recovery was above the limits in PAH-SIM analysis for sample 13-NK-05-SO. Associated positive results were qualified as estimated (JM).

4.1. Detection Limits and Reporting Limits

The detection limit and/or reporting limit was above the 18 AAC 75 cleanup levels for a number of compounds. Note that not detected results where the detection limit was above the ADEC established cleanup level cannot be used to assess the presence or absence of the analyte at concentrations above the cleanup criteria and below the

ERM 14 12/18/2013

reported detection limit. The number of analytes with detection limits or reporting limits above cleanup levels was largely a function of the very broad range of the analyses performed; targets included 165 different indicator compounds and surrogates that are considered indicative of contamination from drum sites. This section details the causes for detection limits and/or reporting limits being above 18 AAC 75 cleanup levels.

The case narrative provide by the laboratory generally indicates that (in the AK102 range) the chromatographic pattern is consistent with a weathered middle distallate.

These findings are consistent the presence of diesel fuel contamination that is known to be present throughout the area. Measured concentrations of DRO ranged from 42.8 to 272 mg/kg.

For SW8270D analysis, the detection limit and/or reporting limit was above the ADEC cleanup level for migration to groundwater in soil, noted in bold and highlighted in yellow in Table D-1, for the following analytes: 1,2,4-trichlorobenzene, 1,4-dichlorobenzene, 2,4-dinitrophenol, 2,4-dinitrotoluene, 2,6-dinitrotoluene, 3,3'-dichlorobenzidine (and its salts), dichloroethyl ether, hexachlorobenzene, hexachlorobutadiene, hexachlorocyclopentadiene, hexachloroethane, nitrobenzene, n-nitrosodimethylamine, n-nitrosodi-n-propylamine, p-chloroaniline, and pentachlorophenol. The detection limit and/or reporting limit was above the ADEC cleanup level for direct contact for benzo(a)pyrene and dibenzo(a,h)anthracene. Note that analytical method 8270D SIM was also used, which provides lower detection limits for PAH compounds.

For 8270D analysis, samples with elevated detection limits were generally analyzed at a dilution due to matrix interference with internal standards. This resulted in elevated detection limits for some compounds. For these analyses, non-target compounds (possibly biogenic compounds) interfered with internal standards. Soils were described as silt with some native woody debris, grey, and damp. Thus, they were known to have relatively high levels of naturally-occurring, non-target organic compounds.

For 8260B analysis, the detection limit and/or reporting limit was above the ADEC cleanup level for migration to groundwater in soil for the following analytes: 1,1,2,2-tetrachloroethane, 1,1,2-trichloroethane, 1,1-dichloroethene, 1,2,3-trichloropropane, 1,2-dichloroethane, 1,2-dichloropropane, carbon tetrachloride, dibromochloromethane, ethylene dibromide, methyl bromide, methylene chloride, and vinyl chloride. Elevated detection limits were likely due to a number of factors. For some compounds, such as vinyl chloride and ethylene dibromide, providing detection limits lower than the 18 AAC 75 migration to groundwater standard is generally not possible without specialized analytical techniques. Samples for 8260B analysis need to be fully covered with methanol. Within that requirement, the higher mass of soil provided the lower the detection limit will be. Ideally, samples will contain at least 50 grams (g) of soil for an initial weight. With some soil types, particularly soils that contain a high fraction of organics (which tend to be less dense), this can be difficult or impossible. Sample

ERM 15 12/18/2013

weights are as follows: 13-NK-01-SO: 52.374 g, 13-NK-02-SO: 41.288 g, 13-NK-03-SO:

39.138 g, 13-NK-04-SO: 47.193 g, 13-NK-05-SO: 45.922 g, and 13-NK-06-SO: 48.109 g. So for some samples, low sample mass may have contributed to elevated detection limits.

Finally, low percent solids (i.e. saturated soils) tend to produce elevated detection limits.

Sample percent solids are as follows: 13-NK-01-SO: 72.4%, 13-NK-02-SO: 76.6%, 13-NK- 03-SO: 75.7%, 13-NK-04-SO: 72.0%, 13-NK-05-SO: 74.1%, and 13-NK-06-SO: 68.0%. So, low percent solids may have contributed to elevated detection limits.

The total overall calculated completeness of the October 2013 set is 100%, which meets the established 85% completeness data quality objective. The full QA/QC report and ADEC Laboratory Data Review Checklists are included in Appendix F.

ERM 16 12/18/2013

ERM 17 12/18/2013

5. CONCEPTUAL SITE MODEL

This section presents a human health conceptual site model (CSM) for the site. This CSM is an updated version of the baseline CSM. The baseline CSM was generated based on data collected during an initial site characterization event in August 2011. The baseline CSM, included in the document titled Napaskiak Former Bureau of Indian Affairs School Day Tanks Site Characterization Report, shows the exposure pathways that presented a potential concern at that time (ADEC 2012a). The baseline CSM was later updated in consideration of analytical results from soil samples collected in October 2012 following treatment (landfarming) of contaminated soils at the site. The updated CSM and graphic form, included in the document titled Napaskiak Remediation Work Plan, explain how each of the exposure pathways has been or will be addressed (OASIS 2013a). The baseline and updated CSM graphic and scoping forms are included in Appendix G. A revised CSM, based on data collected during the October 2013 buried drum assessment event, is not warranted, as additional completed exposure pathways were not identified.

5.1. Receptor Profile

Receptors for the current scenario include residents, construction workers, subsistence harvesters and consumers, and site visitors and trespassers. The LKSD plans to build a new school on the former BIA School site, so schoolchildren, faculty, and staff can be considered potential future receptors.

5.2. Exposure Pathways

At landfarm cells A and B, contamination is present in surface soils. The distribution of contamination at cell A also includes contamination as deep as 8 ft bgs. Increasing concentrations with depth at landfarm cell A suggest that contamination may have migrated to the groundwater table and then spread as a light non-aqueous phase liquid.

The presence of shallow groundwater and current groundwater use in the area make the groundwater ingestion, direct contact, and inhalation of volatile compounds potentially complete exposure pathways. Ongoing monitoring of the water supply will be required to protect drinking water wells located in the Water Treatment Plant and the School Well House. Contaminants above drinking water maximum contaminant levels, or in the case of DRO, the 18 AAC 75 Table C groundwater cleanup levels, represent a potentially unacceptable risk if ingestion were to occur. If contaminants were detected above these levels, it would trigger the need to take additional measures to eliminate these exposure pathways. Such additional measures might include treating the water or switching to an alternate water source.

The ADEC has not published cleanup levels that specifically consider subsistence activities. Thus, a potential risk associated with use of the area by subsistence harvesters and consumers is difficult to assess. Based on preliminary plans for school construction, both landfarm cells are to be capped. Per those same plans, the extent of landfarm cell B

ERM 18 12/18/2013

would be located under the school building. This would prevent subsistence exposure and direct contact to the contamination in that area. School construction plans call for the extent of landfarm cell A to become a grass field. The cap would prevent exposure to the residual contamination.

While the site is close to Napaskiak Slough, the river is silty and likely not be used for drinking water making the surface water ingestion/contact and sediment contact pathways incomplete.

Table 4 summarizes the potential exposure pathways. Although the available data suggest that unacceptable exposure to site contaminants is not currently taking place, additional steps will be necessary to ensure that unacceptable exposure does not occur in the future. These steps are presented in Section 6.

ERM 19 12/18/2013

Table 4: POTENTIAL EXPOSURE PATHWAYS

Exposure Pathway

Do Contaminant Concentrations

Exceed Published Standards?

Exposure Pathway

Complete?

Discussion

Incidental soil ingestion No No

Using landfarming, soil contamination near and beneath former above-ground storage tanks (AST) between 0 and 18 inches bgs was treated below concentrations that pose a potential risk due to the ingestion exposure pathway. Note that ADEC regulations consider surface soils to extent to 2 ft bgs. A cover, consisting of a geomembrane, 2 feet of structural fill, and 4 inches of top soil will prevent incidental ingestion.

Dermal absorption No No

Using land farming, soil contamination near and beneath former ASTs between 0 and 18 inches bgs was treated below concentrations that pose a potential risk due to dermal exposure. Note that ADEC regulations consider surface soils to extent to 2 ft bgs. A cover, consisting of a geomembrane, 2 feet of structural fill, and 4 inches of top soil will prevent dermal exposure.

Ingestion of groundwater

Yes (but not at drinking wells) No

Drinking water wells in the area were not impacted during the 2011 or 2012 monitoring events event; however, groundwater contamination is present at concentrations that could pose a human health risk if it were to be used as drinking water. Continued monitoring is necessary to ensure that the water supply remains safe.

Ingestion/contact of surface water/sediment

Surface water and sediment samples have not been collected

No

Although surface water and sediment samples have not been collected, the available data do not indicate that they have been impacted. Silty water in slough is not used for drinking water.

Ingestion of wild food No standards set No

As detailed in the text, plans call for both landfarm cells to be capped, which would prevent exposure via this pathway.

Inhalation of outdoor air No No

Contaminant concentrations measured in soil are below values that would suggest a potential risk due to outdoor air inhalation.

Inhalation of indoor air No standards set No

A new school will be built on the site; the school will be built on piles. The method of construction will present an air gap between the contaminated soil and the building. This will minimize accumulation of vapors within the building and protect the occupants.

ERM 20 12/18/2013

ERM 21 12/18/2013

6. CONCLUSIONS AND RECOMMENDATIONS

Review of historical drawings/as-built drawings indicated a potential buried drum pit existed in an area of the former BIA school site in Napaskiak, Alaska where future construction is planned for a new school. ERM conducted an assessment of possible buried drums in this area in order to determine the presence and density of suspected drums.

6.1. Conclusions

ERM and Cruz personnel excavated two approximately 50-ft-long trenches (plus additional test pits), in an “X” pattern, across the area of suspected buried drums in order to verify the presence of buried drums.

During the installation of the assessment trenches, a volume of buried drums was located below a portion of the eastern half of the currently-fenced-in landfarm (Cell A) and is an estimated 16 ft wide (north to south) and 22 ft long (east to west). The 55-gallon steel drums appear to be arranged in a single layer of drums lying on their sides and buried beneath approximately 1.5 to 3 ft of soil. All of the drums encountered appear to have had holes cut in them and the bungs removed prior to burial. No sign of sheen, hydrocarbon odor, or other contaminant odor was observed during the excavation of the assessment trenches. A total of five soil samples were collected from the floors of the trenches and test pits within, and proximal to, the area of buried drums to characterize potential contamination.

Analytical results provide additional evidence that the drums were likely empty when buried. The sample collected from location SO-2 was the only sample to contain an analyte concentration above an ADEC Soil Cleanup Level. The DRO concentration at this location was 272 mg/kg which exceeded the 250 mg/kg ADEC 18 AAC 75.341 Table B2 Method Two – petroleum hydrocarbon soil cleanup level for migration to groundwater. All other analytes were either below ADEC Table B1 and B2 Method Two

- soil cleanup levels for the under 40-inch zone or were not detected.

In accordance with the final Trench Installation for Preliminary Drum Assessment Work Plan, samples were analyzed for a very broad array of compounds. It should be noted that of the 165 analytes the soil was analyzed for, 34 had method detection limits and/or method reporting limits that were above the soil cleanup levels.

6.2. Recommendations

Contamination concentrations in soils at depths less than 1.5 ft below ground surface are above the 18 AAC 75 migration to groundwater standard. Deeper soils are believed to contain higher concentrations of fuel contaminants. Continued protection of human health will rely on the measures being taken to prevent exposure:

ERM 22 12/18/2013

• Over time, rusted, buried drums can pose a hazard. As they begin to rust out, the overlying soil can sluff into the void. This can create a tripping and cutting hazard for anyone who steps into the resulting hole.