GSA I Falls LPOE_Soil Management Plan_Dec 9 2024.pdf

United States General Services Administration Future Expansion Area of International Falls Land Port of Entry Soil Management Plan

DRAFT

Soil Management Plan Future Expansion Area of International Falls Land Port of Entry

Four Parcels Located at 4th Street East (State Highway 11), International Falls, Koochiching County, Minnesota

Contract No. 47QRAA18D0074 Order No. 47PA0322F0056

Prepared For:

United States General Services Administration Energy, Environmental, and Sustainability Branch

GSA/PBS, Facilities Management and Services Programs Division 230 S. Dearborn St. Suite 3600, Chicago, IL 60604

Prepared By:

Potomac-Hudson Engineering, Inc.

2305 Historic Decatur Road, Suite 100

San Diego, California 92106 December 2024

Soil Management Plan

TABLE OF CONTENTS i

DELIBERATIVE – FOR OFFICIAL USE ONLY

TABLE OF CONTENTS

Chapter 1 Soil Management & Disposal of Contaminated Material................................................ 1-1

1.1 Soil Reuse .................................................................................................................................. 1-1

1.2 Pre-Excavation Activities .......................................................................................................... 1-1

1.3 Excavation .................................................................................................................................. 1-1

1.3.1 Dust Control ....................................................................................................................... 1-1

1.3.2 Temporary Staging of Contaminated Soil .......................................................................... 1-2

1.3.3 Erosion Control Measures .................................................................................................. 1-3

1.3.4 Construction Debris Screening, Decontamination & Disposal .......................................... 1-3

1.3.5 Decontamination ................................................................................................................ 1-3

1.4 Transportation ............................................................................................................................ 1-4

1.4.1 Manifests ............................................................................................................................ 1-4

1.4.2 Loading .............................................................................................................................. 1-4

1.5 Off-Site Disposal ........................................................................................................................ 1-4

1.5.1 Soil ..................................................................................................................................... 1-4

1.5.2 Construction Debris ........................................................................................................... 1-5

1.5.3 Water .................................................................................................................................. 1-5

Chapter 2 Institutional / Engineering Controls ................................................................................... 2-1

2.1 Institutional Controls ................................................................................................................. 2-1

2.2 Possible Engineered Barrier Components .................................................................................. 2-1

2.3 Imported Clean Fill Material ...................................................................................................... 2-1

APPENDICES

Appendix A – Figures of Sampling Locations and Exceedances from Past Site Investigations

Appendix B – Analytical Testing Tabular Summaries

Appendix C – Areas of Known and Assumed Contamination

DECEMBER 2024 ES-1

EXECUTIVE SUMMARY

A Soil Management Plan (SMP) has been completed for the future expansion area at the International Falls Land Port of Entry located at 4th Street East (subject property), Koochiching County in International Falls, Minnesota. This SMP is being completed to provide a framework on how the impacted soil on the subject property should be handled during the construction and redevelopment activities planned for 2025.

It should be noted that this general SMP is subject to change once the General Service Administration (GSA) enters into Minnesota’s Voluntary Investigation & Cleanup (VIC) program, as currently planned, and Minnesota Pollution Control Agency (MPCA) begins involvement in the cleanup. This SMP will ultimately become a portion of a Response Action Plan (RAP), which will be required to be prepared as part of the VIC program. The location of engineered barriers (asphalt roadways, building foundations, clean soil, etc.) and the use of institutional controls (real property affidavit, environmental covenants and easements, etc.) will most ultimately be based on the final risk assessment performed as part of the RAP and the specific direction of the MPCA.

Also, the site investigation work needs to be completed on the PCA parcel and additional sampling will need to be completed in order to strengthen this SMP and for the RAP. Lastly, any changes to the site design and proposed layout will require updates to the SMP and the RAP.

In December of 2022, Potomac-Hudson Engineering, Inc (PHE) completed a Phase I Environmental Site Assessment (ESA). The Phase I ESA noted the following Recognized Environmental Conditions (RECs) associated with the subject property:

• REC-1: Presence of residual soil contamination on Parcel No. 92-060-00430. On October 10, 1995, a leaking underground storage tank (LUST) was reported on the eastern-most parcel of the Site. A limited Site Investigation (LSI) was submitted to the Minnesota Pollution Control Agency (MPCA) on June 28, 2006, concluding that only low concentrations of assumed petroleum contaminants were left present in the soil. The MPCA granted the parcel site closure on September 29, 2006. However, in the closure letter, MPCA stated the following: “If future development of this property or the surrounding area is planned, it should be assumed that petroleum contamination may still be present.

• REC-2: Historical presence of soil contamination on Parcel No. 92-060-00430. A 2006 Phase I ESA report provided by the current property owner (Recreation Land Development, LLC) of the eastern-most parcel of the Subject Property indicates that under the previous occupants (Virginia Ready-Mix Concrete Company; Falls Ready Mix Concrete Company) site investigations were conducted in 1991 and 1994. The historical investigations revealed a number of potential soil contamination sources including: a 1,500-gallon, partially buried used oil tank; a 750-gallon diesel fuel aboveground storage tank (AST); improper storage of numerous uncovered used batteries; several “liquid waste” barrels stored outdoors and in “precarious situations” with missing bungs; and scrap concrete and metal reportedly buried on-site. The 2006 Phase I ESA report indicates these observations were addressed by the former tenant via excavation activities, however, no data or reports have been provided, and there is no indication that consultation with MPCA ever occurred.

• REC-3: Presence of leachate line from a nearby landfill to a neighboring paper mill for treatment prior to discharge. Across the northern portion of the Subject Property, runs a mostly buried leachate line transporting material from a nearby landfill (Moonlight Rock) to a neighboring paper mill, located to the west of the Subject Property, from treatment. Due to the buried nature of the line, unseen leaks and subsurface soil contamination are possible from the untreated leachate.

DECEMBER 2024 ES-2

• REC-4: Potential soil and groundwater contamination as a result of pesticide and creosote treatments on historical railroad tracks. Railroad tracks were historically located onsite, from at least 1919 until the early 1980s. These tracks were formerly located running along the northern extent of the Subject Property, in the same location as the present-day access road. Historical use of pesticides and creosote to treat the tracks could have potentially contributed to soil and groundwater contamination.

• REC-5: Presence of numerous industrial and oil-related facilities nearby with known instances of past and present contamination. The number of nearby properties with known or suspected environmental contamination does present a concern for the Subject Property. Even though GSA would not be liable for groundwater contamination that originates off-site from a third- party, the potential exists for vapors from groundwater contamination to migrate into occupied space of the current or future buildings, creating a health and safety concern.

In order to address the above-mentioned RECs, from July of 2023 through July of 2024, PHE completed several site investigations at the subject property. Figures showing the site investigation soil boring and monitoring well locations are provided in Appendix A. Tabular summaries of the testing results are provided in Appendix B.

The initial site investigation was completed from July 10-12, 2023. The initial investigation concluded the following:

Due to the widespread presence of chromium in subsurface soils, it is also possible that chromium exists in surface soils as well. Given the amount of dust generated by truck traffic, PHE recommends surface soil sampling be conducted for RCRA metals analysis. It is also recommended that the analysis speciate the chromium results to provide a quantification of chromium III compared to chromium VI in the samples results. A total of 10 samples are proposed. To further assess thallium onsite, PHE likewise recommends a total of 10 soil samples for thallium be collected across the Site, at depth ranging from the surface to 10 feet bgs.

• Concerning REC-1 and REC-2, PHE concludes no further action is recommended at this time.

• Concerning REC-3, PHE concludes that sampling of the leachate effluent itself should be conducted for comparison to soil analytical results. PHE recommends aqueous samples of the leachate be collected at the Moonlight Rock Landfill at the far upstream end of the leachate line.

Analyses should include SVOCs, metals, and dioxins/furans.

• Additionally, an attempt should be made to quantify the extent of the apparent leachate release adjacent to REC- 3-3 and perform further assessment along previously unsampled portions of the line. To that end, PHE recommends 6 additional borings be investigated and sampled in the areas of REC-3-3 and the adjacent manhole. In addition, further soil borings should be investigated along the leachate line between REC3-3 and REC3-4. To accomplish this, the location of the leachate line will need to be determined. This can be accomplished through a combination of mini-excavator combined with hand digging to safely locate and expose the leachate line. Once the line location is known, additional soil borings can be advanced, and samples can be collected. A total of 10 boring should be investigated along the line between REC-3-3 and REC-3-4, with at least one sample collected from each boring location.

• Concerning REC-4, PHE concluded that the soil associated with the former railroad tracks has been adequately assessed. Therefore, no additional in-situ soil sampling is recommended at this time. If any soil from this area is excavated, soil sampling for RCRA metals plus copper is recommended to characterize the soil prior to potential reuse or offsite disposal.

DECEMBER 2024 ES-3

• Concerning REC-5, PHE concludes no further action is recommended at this time.

• Concerning soil piles, PHE recommends that additional soil sampling be completed to determine if the presence of arsenic was an anomaly or indicative of a more widespread concern.

• Concerning the former incinerator, PHE recommends that additional soil sampling be completed both horizontally and vertically to determine if higher concentrations of dioxins/furans are present in this area. PHE recommends 5 additional borings be investigated and a total of 10 additional samples be collected at various depths from the surface to 10 feet bgs. Analysis should be for dioxins/furans.

Subsequent site investigations were completed from March 18-20, 2024, and July 22-25, 2024. These subsequent investigations were completed to further delineate contamination that was noted on the Recreation Land Development, LLC (RLD) property. No subsequent investigations have been completed on the PCA property to date, due to a denial of right of entry on the parcel following the July 2023 investigation. These subsequent investigations noted the following:

During this investigation, dioxins and furans were detected in soil along and adjacent to the former (removed) section of the leachate line at concentrations above both the Minnesota Pollution Control Agency’s (MPCA’s) most stringent Residential/Recreational Soil Reference Values (SRVs) and Commercial/Industrial SRVs in two of the samples collected. Dioxins and furans were also detected in 5 additional samples but at concentrations below their SRVs. This provides further confirmation that the leachate line has leaked historically.

During this investigation, dioxins and furans were detected in a total of 13 soil samples collected. Of these, 2 soil samples collected along and adjacent to the former (removed) section of the leachate line and 1 soil sample collected from soil/debris piles contained concentrations of dioxins/furans which exceeded both the Minnesota Pollution Control Agency’s (MPCA’s) most stringent Residential/Recreational Soil Reference Values (SRVs) and Commercial/Industrial SRVs. In addition, 5 of the soil samples collected contained concentrations of dioxins and furans that exceeded MPCA’s Residential/Recreational SRVs but were below their respective Commercial/Industrial SRVs. The final 5 samples contained detections of dioxins and furans but at concentrations below both their respective Residential/Recreational SRVs and the Commercial/Industrial SRVs. These results provide further confirmation that the leachate line has leaked historically.

Additionally, arsenic was detected at concentrations above MPCA’s Commercial/Industrial SRV in 1 sample collected along the former section of the leachate line, and 1 sample collected from a soil/debris pile. Both arsenic exceedances were collected from samples that also had dioxin and furan

Commercial/Industrial SRV exceedances. Arsenic was also detected in 13 other samples at concentrations below its SRVs. The presence of dioxin, furan, and arsenic exceedances in samples collected from the soil/debris piles (which reportedly originated from the uncovered First Creek) may have come from the area of First Creek where the existing leachate line crosses it. These results may also indicate that similar leachate line contamination may be present in other portions of the soil piles located on this parcel.

A total of 9 groundwater samples (plus 1 environmental duplicate sample) were also collected, which included 6 samples from temporary well points (TWPs) and 4 samples (including the environmental duplicate sample) from permanent monitoring wells (MWs). These samples were analyzed for semi- volatile organic compounds (SVOCs), dioxins/furans, and metals.

Manganese was detected in one groundwater at a concentration which exceeded its Minnesota Department of Health (MDH) Health Risk Limit (HRL). One or more metals were detected in 7 of the other 8 samples (one MW did not yield sufficient water to collect a sample fraction for metals analysis) but at concentrations below MDH HRLs. Dions/furans were detected in 3 TWP samples but at concentrations below MDH HRLs.

DECEMBER 2024 ES-4

(Results for dioxins/furans from the MWs were not available at the time of this draft report; these results will be either included in the final report, or as a supplemental letter report.) SVOCs were not detected in any groundwater samples collected.

DECEMBER 2024 1-1

CHAPTER 1 SOIL MANAGEMENT &

DISPOSAL OF CONTAMINATED MATERIAL

A Soil Management Plan (SMP) has been completed for the future expansion area at the International Falls Land Port of Entry located at 4th Street East (subject property), Koochiching County in International Falls, Minnesota. This SMP is being completed to provide a framework on how the impacted soil on the subject property should be handled during the construction and redevelopment activities planned for 2025.

This section offers guidelines for handling soils and materials during any future subsurface construction activities at the subject property to minimize releases to the environment, protect worker health and safety, and ensure that contaminated materials are properly managed during construction activities. The Contractor will be required to comply with existing laws, regulations, rules, standards, policies, and procedures pertaining to safety standards and environmental rules to minimize the potential for releases, spills, and discharges.

1.1 SOIL REUSE

A request can be submitted to the Minnesota Pollution Control Agency (MPCA) to reuse excavated soil on-site as backfill material. The guidelines for re-using onsite soil can be found in the MPCA’s Brownfield Program Response Action Plans regulations (Minn.Stat.115B & 115C).

1.2 PRE-EXCAVATION ACTIVITIES

The Contractor will develop its own trenching and shoring specification and will be responsible for preparing any required permit authorizations. The permits shall be approved by the appropriate authorizing agency and will be the responsibility of the Contractor.

The Contractor shall contact Gopher State One Call (811) utility locating service a minimum of three days prior to excavation at the site to complete a subsurface utility review in any areas of planned excavation.

Utilities should be marked with stakes or flags in accordance with the American Public Works Association color codes. It should be noted that Gopher State One Call will not locate on-site private utilities; therefore, the Contractor shall contract with a private utility-locate company to complete on-site utility locates.

Temporary erosion controls, in the form of silt fencing, should be installed around excavation areas if necessary.

1.3 EXCAVATION

1.3.1 Dust Control

Fugitive dust and offsite migration will be controlled using the following methods, as specified in the Record of Decision for the Supplemental Environmental Impact Statement prepared for the project:

• Using water for dust control when grading roads or clearing land;

• Stabilize open storage piles and disturbed areas by covering and/or applying water or organic dust palliative where appropriate. This applies to both active and inactive sites during workdays, weekends, holidays, and windy conditions;

• Paving roadways and maintaining them in a clean condition;

• Covering open equipment when conveying or transporting material likely to create objectionable air pollution when airborne; and

• Promptly removing spilled or tracked dirt or other materials from paved streets.

DECEMBER 2024 1-2

• Install wind fencing and phase grading operations where appropriate and operate water trucks for stabilization of surfaces under windy conditions.

In addition, air monitoring of the perimeter and work zone may be conducted by the Contractor using a dust monitor.

1.3.2 Temporary Staging of Contaminated Soil

Construction activities may generate spoils containing concentrations of constituents above the MPCA’s Soil Reference Values (SRVs). Temporary stockpiling of excavated materials that were found to have contaminant concentrations above the MPCA SRVs, during the site investigation activities, shall be performed in accordance with applicable federal, state, and local rules and regulations.

Based on current site investigation sampling data, several discrete areas of known soil contamination occur along the existing and former leachate line as well as within the soil piles on the subject property (refer to the Figures in Appendix C). However, since additional site investigation activities have not yet been completed on the PCA parcel, it is possible that additional areas of soil contamination may be identified during future sampling events. At present, as a conservative assumption, unsampled areas of soil within 20 feet on either side of the existing leachate line on the PCA parcel, to a depth of at least 5 feet below ground surface should also be assumed to be contaminated, until and unless further sampling is conducted to demonstrate otherwise. A minimum depth of 5 feet is assumed as contaminated as it is consistent with the depth at which contamination was identified along the existing leachate line (down to 4.5 feet below ground surface); however, for stockpiling purposes, segregation of excavated material to the necessary applicable depth in the areas of the existing leachate line may be more efficient. As such, stockpiling of this contaminated soil should be performed in accordance with applicable federal, state, and local rules and regulations. Figures showing the locations of assumed soil contamination along the existing leachate line within the PCA parcel are also included in Appendix C.

Further, soil sampling has generally only been conducted to depths between 0 and 10 feet below ground surface (bgs); soil cuttings from any potential installation of wells (e.g., geothermal wells) onsite beyond 10 feet bgs, regardless of their location within areas of known or assumed contamination, should be sampled by the drilling contractor for characterization purposes prior to staging or mixing with known “clean” (i.e., uncontaminated) soil.

The minimum stockpile handling and management criteria for contaminated or potentially contaminated materials include the following:

• Segregate excavated materials based on known testing results, obvious staining, obvious odor, or other physical characteristics.

• The designated temporary stockpiles shall not be staged near sensitive human health receptors such as public or private water supply wells or sensitive environmental receptors such as wetlands, surface water bodies, or marine environments.

• Designated temporary stockpile areas shall be located in secured areas of the subject property to restrict access.

• Excavated materials may not be placed directly on top of imported clean fill or staged outside of the subject property boundaries.

• Appropriate actions shall be taken to prevent erosion/transport of the soil by surface water runoff, and to limit dust generation.

DECEMBER 2024 1-3

• Excavated materials will be stored at the subject property for the shortest time possible until the materials can be returned to the area from which they were excavated, placed as backfill within the boundaries of the subject property, or transported off site for disposal.

1.3.3 Erosion Control Measures

During future subsurface construction activities, the generation of potentially contaminated runoff may occur that will require management by the Contractor.

• As needed for erosion control and to prevent contaminants from mixing with runoff and migrating off site, diversion structures will be constructed to divert water away from the locations where contaminated media is stockpiled.

• To the extent practical, runoff water will be routed away from active work areas or to drainage structures within the work areas.

• Contaminated runoff will be managed in accordance with applicable regulations.

• Since the project will involve the disturbance of more than one acre of soil, the Contractor will be required to apply for coverage under the MPCA National Pollutant Discharge Elimination System/Site Disposal System (NPDES/SDS) as per the Clean Water Act, a construction stormwater general (MNR100001) permit, and follow the requirements with respect to soil erosion and sediment control measures.

1.3.4 Construction Debris Screening, Decontamination & Disposal Construction debris (concrete, bricks, asphalt, etc.) may be screened and segregated from the excavated soil. This construction debris will either be further separated for offsite disposal as a non-hazardous special waste or for offsite disposal at a licensed construction debris fill operation.

If necessary, the construction debris will be decontaminated by removing all soil material from the surface using hand tools. Decontamination should only be conducted in a designated area of the site to prevent cross-contamination. The decontaminated construction debris can then either be directly loaded into dump trucks for disposal or stored at an approved, designated area of the site for later disposal. If the construction debris must be broken down to meet the size requirements of the licensed construction debris landfill, this must be performed in a designated area of the site.

Temporary stockpiling of construction debris shall be performed in accordance with applicable federal, state, and local rules and regulations. The following outlines the minimum stockpile handling and management criteria for construction debris.

• Segregate materials based on the requirements of the planned disposal facility.

• Designated temporary stockpile areas shall be located in secured areas of the subject property to restrict access.

• The designated temporary stockpiles shall not be staged near sensitive human health receptors such as public or private water supply wells or sensitive environmental receptors such as wetlands, surface water bodies, or marine environments.

• Construction debris may not be placed directly on top of imported clean fill or staged outside of the subject property boundaries.

1.3.5 Decontamination

Prior to leaving the site and prior to handling imported clean soil for use in engineered barrier areas, all major equipment, tools, and materials should be cleaned to remove encrusted dirt.

DECEMBER 2024 1-4

1.4 TRANSPORTATION

This section establishes the procedures for handling the transportation of waste generated during construction activities. All waste streams must be properly characterized, transported, and disposed of in accordance with all local, state, and federal laws. Soil that will be disposed of off-site should be disposed of at a Minnesota Permitted Solid Waste Management Facility.

1.4.1 Manifests

The Contractor will prepare waste characterization profiles, manifests, and any additional waste shipping documents on behalf of the Owner/Generator. The aforementioned documentation will be reviewed and signed by the Owner or the Owner’s designated representative.

Waste manifests or tracking receipts are required for all non-hazardous, special waste and/or non-hazardous, non-special waste in accordance with 49 CFR 172. All shipping containers will be marked and labeled in accordance with the regulations set forth in 49 CFR 172.

Each load of special waste or non-special waste will be shipped with an individual manifest or tracking receipt indicating the approximate volume being transported. A copy of the manifest or tracking receipt will be signed by the disposal facility when it is accepted for disposal. The disposal facility will document the weight of each load, and the Contractor will provide copies of the manifests or other appropriate waste documentation data to the Owner/Generator or the Owner’s Consultant.

Transportation of waste not requiring manifests or other appropriate waste documentation will be tracked by the Contractor. The Contractor will maintain a log of all waste being transported off site, and the log will be provided to the Owner/Generator or the Owner’s Consultant upon completion of the project, or at the Owner’s request.

1.4.2 Loading

All vehicles leaving the site should minimize the tracking of mud and dirt on site or on public thoroughfares.

A traffic plan that prohibits access across any landscaped areas of the subject property shall be prepared by the Contractor. A street sweeper and water truck may be necessary to minimize the tracking of mud and dirt and to prevent fugitive dust from leaving the site.

1.5 Off-SITE DISPOSAL

1.5.1 Soil

If it becomes necessary to dispose of excavated soils, soils will be appropriately characterized and permitted for off-site disposal. This includes any soil from drill cuttings from installation of wells (e.g., geothermal wells) onsite. Based on the existing sampling data collected as part of the site investigation activities conducted to date, it is anticipated that soil from the site generated during earth moving and excavation activities, including in areas of known contamination, will likely be designated as non-hazardous, certified non-special waste. Soil sampling has generally only been conducted to depths between 0 and 10 feet bgs;

soil cuttings from any potential well drilling beyond 10 feet bgs, regardless of their location within areas of known or assumed contamination, should be sampled by the drilling contractor prior to being disposed of offsite to determine the appropriate destination facility.

Any spoils that exhibit obvious chemical or petroleum odors, or staining shall be presumed to be contaminated, and undergo proper waste characterization/profiling.

Contaminated soils meeting the criteria for management and disposal as a non-hazardous, certified non-special waste can be disposed of at a Permitted Solid Waste Management Facility; however, formal landfill review of analytical testing data will be required to confirm appropriate handling and disposal requirements.

DECEMBER 2024 1-5

1.5.2 Construction Debris

Construction debris will be segregated from the contaminated soil waste stream in accordance with the procedures previously described and loaded into dump trucks for disposal at a licensed construction debris landfill.

1.5.3 Water

Water generated during construction activities including stormwater, groundwater, and decontamination water, will be managed in accordance with all federal, state, and local regulations.

Any water exhibiting a sheen or suspected chemical, or petroleum odors shall undergo analytical testing to determine proper handling and disposal requirements.

Water from excavations cannot be pumped to a storm sewer unless the Contractor has obtained permission from the local municipality.

DECEMBER 2024 2-1

CHAPTER 2 INSTITUTIONAL / ENGINEERING CONTROLS

2.1 INSTITUTIONAL CONTROLS

Institutional Controls (ICs) are administrative or legal tools that help minimize the potential for exposure to contamination and/or protect the integrity of a response action. An IC limits how a property or its resources can be used and/or provides information that helps guide behavior on the property, to protect human health or the environment.

As stated in the executive summary section of this SMP, the use of institutional controls (real property affidavit, environmental covenants and easements, etc.) will ultimately be based on the final risk assessment performed as part of the RAP and the specific direction of the MPCA. It is likely that any contaminated soil left onsite will be subject to institutional controls which will place limits on future land use and outline requirements for future earth-moving activities. It may also require periodic inspection and reporting.

2.2 POSSIBLE ENGINEERED BARRIER COMPONENTS

At present, the engineered barrier components may include the following:

• asphalt pavement that meets the site development specifications

• concrete pavement that meets the site development specifications

• concrete building foundations that meet the site development specifications

• virgin aggregate or clean imported soil in unpaved areas As indicated in the executive summary section of this SMP, the location and extent of engineered barriers (asphalt roadways, building foundations, clean soil, etc.) will ultimately be based on the final risk assessment performed as part of the RAP and the specific direction of the MPCA. Engineered barriers are assumed to be required in known and presumed contaminated areas identified in the Appendix C figures.

As per MPCA’s Soil Reference Value Technical Support Document, it is assumed that virgin aggregate or clean imported soil will be required in unpaved areas at most down to four feet below ground surface, or what is known as the ‘Accessible Zone’. In areas of impervious surface (i.e., asphalt or concrete pavement, or concrete building foundations), two feet of clean soil may be necessary under all newly constructed pavements and buildings. Exact depths and extent of clean fill associated with engineered barriers will be determined by MPCA and based on the results of the risk assessment performed as part of the RAP.

2.3 IMPORTED CLEAN FILL MATERIAL

For aggregate or clean imported soil to be used as an engineered barrier component or otherwise, the following methodology must be followed to demonstrate that imported material meets applicable MPCA requirements.

For aggregate sources:

• A letter must be provided from the source facility certifying that the material imported to the subject property is virgin material mined directly from the source quarry.

For imported soil sources:

• The source property must be investigated to determine whether it is listed on any state or federal environmental databases.

• A letter must be provided from the source facility certifying that the material imported to the subject property is clean or meets applicable SRVs.

DECEMBER 2024 2-2

• One soil sample from each source property must be analyzed for contaminants of concern to confirm that the soil intended for use at the subject property meets the most stringent SRVs.

If aggregate is not from a virgin source, or clean soil materials do not meet the current most stringent SRVs, the material is not acceptable for use as an engineered barrier at the subject property.

DECEMBER 2024 APPENDIX A

Appendix A Figures of Sampling Locations and Exceedances from Past Site

Investigations

A-1: Figures from July 2023 Sampling Event

A-2: Figures from March 2024 Sampling Event

A-3: Figures from July 2024 Sampling Event

DECEMBER 2024 APPENDIX B

Appendix B Analytical Testing Tabular Summaries

B-1: Tables from July 2023 Sampling Event

Table 1 - VOCs and SVOCs Soil Sample Results Future Expansion Area at the International Falls Land Port of Entry 4th Street East, international Falls, Koochiching County, Minnesota

Sample ID Sample

Date Sample

Time

Sample Depth

(inches) A ce na ph th al en e

A nt hr ac en e

B en zo [a

]a nt hr ac en e

B en zo [a

]p yr en e

B en zo [b

]fl uo ra nt he ne

B en zo [g

,h ,i] pe ry le ne

B en zo [k

]fl uo ra nt he ne

C hr ys en e

D ib en z[ a, h] an th ra ce ne

Fl uo ra nt he ne

Fl uo re ne

In de no (1

,2 ,3

-c d) py re ne

Ph en an th re ne

Py re ne

2-m at hy ln ap ht ha le ne

N ap ht ha le ne

D ib en zo fu ra n

1, 2, 4-tr im et hy lb en ze ne p- Is op ro py lto lu en e

Xy le ne s, T ot al

2, 4, 5-tri ch lo ro ph en ol

Pe nt ac hl or op he no l

A ll

O th er S

VO

C s

A ll

VO

C s

MPCA Res/Rec Acute SRV - - - N/A N/A N/A N/A N/A - N/A N/A N/A N/A N/A N/A - N/A N/A N/A N/A N/A - N/A N/A 5.2 Various Various

MPCA Res/Rec Chronic SRV - - - 460 2800 20 2 20 - 20 200 3.5 210 390 20 - 220 39 81 22 140 - 260 1300 8.8 Various Various

MPCA Com/Ind Chronic SRV - - - 6800 42000 230 23 230 - 230 2300 41 2700 5800 230 - 3200 580 280 320 220 - 260 18000 46 Various Various

DP-1 07/11/2023 14:00 N/A ND ND ND ND ND ND ND ND ND 1.69 ND ND 1.58 1.63 ND ND ND ND ND ND ND ND ND NA DP-2 07/11/2023 14:30 N/A ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND 3.35 ND ND ND ND ND ND ND NA DP-3 07/11/2023 14:15 N/A ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND NA DP-4 07/11/2023 14:25 N/A ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND NA REC-1/2-1-1 07/11/2023 10:25 2 - 2.5' ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND REC-1/2-1-2 07/11/2023 10:43 5 - 6' ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND REC-1/2-2-1 07/11/2023 11:10 1 - 1.5' ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND REC-1/2-2-2 07/11/2023 11:10 7 - 7.5' ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND REC-1/2-3-1 07/11/2023 12:53 1 - 2' ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND REC-1/2-3-2 07/11/2023 12:55 2 - 3' ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND REC-1/2-4-1 07/11/2023 13:05 0.5 - 1.5 ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND REC-2-1-1 07/11/2023 10:00 1.5 - 2' ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND 0.696 ND 0.416 0.295 0.435 ND ND ND ND REC-2-1-2 07/11/2023 10:10 5.5 - 6' ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND REC-2-2-1 07/11/2023 11:15 1 - 1.5' ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND REC-2-2-2 07/11/2023 11:30 5 - 6' ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND REC-2-3-1 07/11/2023 12:00 1 - 1.5' ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND REC-2-3-2 07/11/2023 12:05 9.5 - 10' ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND REC-2-4-1 07/11/2023 12:15 0.5 - 1' ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND REC-2-4-2 07/11/2023 12:20 1 - 2' ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND REC-2-5-1 07/11/2023 12:38 1 - 2' ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND REC-2-5-2 07/11/2023 12:45 2 - 2.5' ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND REC-2-6-1 07/11/2023 13:30 0.5 - 1' ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND REC-2-7-1 07/11/2023 13:40 1 - 1.5' ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND REC-2-8-1 07/11/2023 13:24 0.75 - 1.5' ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND REC-3-1-1 07/12/2023 11:20 0.5 - 1.5' ND ND ND ND ND ND ND ND ND ND NA ND ND ND ND ND ND ND ND ND ND ND ND ND REC-3-2-1 07/12/2023 11:50 6 - 6.5' ND ND ND ND ND ND ND ND ND ND NA ND ND ND ND ND ND ND ND ND ND ND ND ND REC-3-3-1 07/12/2023 12:40 3.5 - 4.5' ND ND 5.94 8.54 9.98 4.87 4.63 6.69 1.68 6.96 NA 5.61 2.23 5.21 ND ND ND ND ND ND ND ND ND ND REC-3-4-1 07/12/2023 12:10 3 - 5' ND ND ND ND ND ND ND ND ND ND NA ND ND ND ND ND ND ND ND ND ND ND ND ND REC-3-5-1 07/12/2023 13:30 1.5 - 2' ND ND ND ND ND ND ND ND ND ND NA ND ND ND ND ND ND ND ND ND ND ND ND ND REC-3-6-1 07/12/2023 14:00 9 - 10' ND ND ND ND ND ND ND ND ND ND NA ND ND ND ND ND ND ND ND ND ND ND ND ND REC-3-7-1 07/12/2023 14:10 3 - 3.5' ND ND ND ND ND ND ND ND ND ND NA ND ND ND ND ND ND ND ND ND ND ND ND ND REC-4-1-1 07/11/2023 16:30 3 - 4' ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND NA REC-4-2-1 07/11/2023 16:40 0.5 - 1.5' ND ND ND ND ND ND ND ND ND ND ND ND 2.49 ND 4.54 2.29 1.16 ND ND ND ND ND ND NA REC-4-3-1 07/12/2023 09:40 1 - 2' NA NA ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND NA REC-4-4-1 07/12/2023 10:00 1 - 2' NA NA ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND NA REC-4-5-1 07/12/2023 10:10 1 - 2' NA NA ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND NA REC-4-6-1 07/11/2023 16:20 1.5 - 2.5' ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND NA REC-4-7-1 07/11/2023 16:10 0.5 - 1' ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND NA REC-4-7-2 07/11/2023 16:15 3.5 - 4' ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND NA REC-4-8-1 07/11/2023 16:00 2 - 3' ND ND ND ND ND ND ND ND ND 2.62 ND ND 2.07 2.15 ND ND ND ND ND ND 1.42 7.50 ND NA REC-4-9-1 07/11/2023 15:50 1.5 - 2' 6.52 2.69 2.69 1.18 1.70 ND ND 2.13 ND 13.2 4.47 ND 9.21 9.97 ND 1.29 2.18 0.219 ND ND ND ND ND NA REC-4-10-1 07/11/2023 09:50 4 - 4.5' ND ND ND ND ND ND ND ND ND 1.44 ND ND 1.59 1.19 ND ND ND ND ND ND ND ND ND NA REC-4-10-2 07/11/2023 10:00 3 - 3.5' ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND NA REC-4-11-1 07/11/2023 10:15 3.5 - 4.5' ND ND ND ND ND ND ND ND ND ND ND ND 1.45 ND ND ND ND ND ND ND ND ND ND NA REC-4-12-1 07/11/2023 10:40 3.5 - 4.5' ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND NA REC-4-13-1 07/11/2023 11:00 3.5 - 4.5 ' ND ND 4.04 4.83 7.07 3.41 2.33 4.86 ND 4.85 ND 4.25 4.78 6.38 ND ND ND ND ND ND ND ND ND NA REC-4-14-1 07/11/2023 11:20 4.5 - 5' ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND NA REC-4-15-1 07/11/2023 11:35 3 - 4' ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND NA REC-4-16-1 07/11/2023 11:55 2.5 - 3.5' ND ND ND ND ND ND ND ND ND ND ND ND ND ND 1.36 ND ND ND ND ND ND ND ND NA REC-4-17-1 07/11/2023 12:15 3.5 - 4.5' ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND NA REC-4-18-1 07/11/2023 13:00 3.5 - 4' ND ND ND ND ND ND ND ND ND ND ND ND ND ND 1.19 ND ND ND ND ND ND ND ND NA REC-4-19-1 07/11/2023 13:25 3.5 - 4.5' ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND NA REC-4-20-1 07/11/2023 13:40 3.5 - 4.5' ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND NA REC-4-21-1 07/11/2023 14:00 3.5 - 4.5' ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND NA REC-4-22-1 07/11/2023 14:20 2.5 - 3.5' ND ND ND ND ND ND ND ND ND ND ND ND ND ND 1.53 1.24 ND ND ND ND ND ND ND NA REC-4-23-1 07/11/2023 14:40 2.5 - 3.5' ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND NA REC-4-24-1 07/11/2023 15:00 3.5 - 4.5' ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND NA REC-4-25-1 07/11/2023 15:20 3.5 - 4.5' ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND NA REC-4-26-1 07/11/2023 15:40 4.5 - 5' ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND NA REC-4-27-1 07/11/2023 16:00 4 - 5' ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND NA INCINERATOR 07/12/2023 12:50 2 - 3' NA NA ND ND ND ND ND ND ND ND NA ND ND ND ND ND ND ND ND ND ND ND ND NA INCINERATOR-2 07/12/2023 12:20 2 - 3' ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND NA Notes:

Values indicated in red exceed MPCA Residential SRVs

A na ly te

S am pl e

R es ul ts

(m g/

K g)

Values indicated in red with highlight exceed MPCA Com/Ind Chronic SRV

PAHs = Polycyclic Aromatic Hydrocarbons; VOCs = Volatile Organic Compounds; SVOCs = Semi-Volatile Organic Compounds; MPCA = Minnesota Pollution Control Agency; SRV = Soil Reference Value; Res/Rec = Residential / Recreational; Com/Ind = Commercial / Industrial; ND = Non Detect; NA = Not Analyzed

Table 2 - Metals, PCBs, and Dioxins/Furans Soil Sample Results

4th Street East, International Falls, Koochiching County, Minnesota

Sample ID Sample

Date Sample

Time

Sample Depth (feet) A rs en ic

B ar iu m

B er yl liu m

C ad m iu m

C hr om iu m

C ob al t

C op pe r

Le ad

M er cu ry

Se le ni um

Si lv er

Th al liu m

Va na di um

To ta l P C

B s

D io xi ns

Fu ra ns

(T ot al

MPCA Res/Rec Acute SRV - - - 9 260 N/A 9.1 N/A N/A 120 N/A N/A N/A N/A N/A N/A N/A N/A

MPCA Res/Rec Chronic SRV - - - 9 3100 31 1.6 2.3 12 2200 200 1.3 78 78 0.29 62 0.82 7.00E-06

MPCA Com/Ind Chronic SRV - - - 9 41000 420 23 62 69 33000 460 3.1 1200 1200 2.3 62 10 2.80E-05

DP-1 07/11/2023 14:00 N/A ND 154 ND ND 26.7 7.76 27.6 34.1 0.12 ND ND ND^ 41 ND NA DP-2 07/11/2023 14:30 N/A ND^ 499 ND ND 20 7.19 69.2 98 0.18 ND ND ND^ 26.3 ND NA DP-3 07/11/2023 14:15 N/A ND 58.2 ND ND 26.2 6.14 14.4 15.9 ND ND ND ND^ 20.3 ND NA DP-4 07/11/2023 14:25 N/A 9.74 135 ND ND 13.3 4.85 27.8 159 0.23 ND ND ND^ 15.9 ND NA REC-1/2-1-1 07/11/2023 10:25 2 - 2.5' ND 74.3 ND ND 25.7 6.84 16.3 7.42 0.04 ND ND ND^ 35.7 NA NA REC-1/2-1-2 07/11/2023 10:43 5 - 6' ND 36.8 ND ND 12.3 3.02 8.81 4.03 0.02 ND ND ND^ 20.5 NA NA REC-1/2-2-1 07/11/2023 11:10 1 - 1.5' ND 31.3 ND ND 11.3 3.26 ND 4.19 ND ND ND ND^ 12.8 NA NA REC-1/2-2-2 07/11/2023 11:10 7 - 7.5' ND 65.3 ND ND 18.2 5.08 9.55 5.46 ND ND ND ND^ 22.4 NA NA REC-1/2-3-1 07/11/2023 12:53 1 - 2' ND 50.4 ND ND 20.3 5.23 9.64 5.71 0.03 ND ND ND^ 28.8 NA NA REC-1/2-3-2 07/11/2023 12:55 2 - 3' ND 76.9 ND ND 25.7 8.29 19.9 7.38 0.03 ND ND ND^ 38.6 NA NA REC-1/2-4-1 07/11/2023 13:05 0.5 - 1.5 ND 88.3 ND ND 30.3 8.85 20.8 9.13 0.03 ND ND ND^ 38.7 NA NA

REC-2-1-1 07/11/2023 10:00 1.5 - 2' NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA

REC-2-1-2 07/11/2023 10:10 5.5 - 6' ND 118 ND ND 44.8 12.7 24.5 12.2 0.02 ND ND ND^ 52.5 NA NA REC-2-2-1 07/11/2023 11:15 1 - 1.5' ND 69.1 ND ND 20.1 6.41 6.69 9.96 0.02 ND ND ND^ 21.1 NA NA REC-2-2-2 07/11/2023 11:30 5 - 6' ND 57.8 ND ND 19.1 7.31 10.3 5.61 0.02 ND ND ND^ 25.7 NA NA REC-2-3-1 07/11/2023 12:00 1 - 1.5' ND 140 ND ND 52 13.9 25.8 10.9 0.05 ND ND ND^ 47.1 NA NA REC-2-3-2 07/11/2023 12:05 9.5 - 10' ND 67.5 ND ND 22 16.6 15 9.42 ND ND ND ND^ 37.6 NA NA REC-2-4-1 07/11/2023 12:15 0.5 - 1' ND 32.2 ND ND 10.8 3.42 ND 4.61 ND ND ND ND^ 12.5 NA NA REC-2-4-2 07/11/2023 12:20 1 - 2' ND 36 ND ND 11.7 2.94 ND 4.17 ND ND ND ND^ 11.7 NA NA REC-2-5-1 07/11/2023 12:38 1 - 2' ND 46.9 ND ND 17.6 5.33 10.2 5.57 ND ND ND ND^ 29.6 NA NA REC-2-5-2 07/11/2023 12:45 2 - 2.5' ND 40.2 ND ND 16.7 5.87 10.2 5.17 ND ND ND ND^ 24.5 NA NA REC-2-6-1 07/11/2023 13:30 0.5 - 1' ND 76.7 ND ND 16.5 4.5 7.46 10.9 ND ND ND ND^ 20.7 NA NA REC-2-7-1 07/11/2023 13:40 1 - 1.5' ND 110 ND ND 40.1 12.9 8.41 7.57 0.02 ND ND ND^ 41.2 NA NA REC-2-8-1 07/11/2023 13:24 0.75 - 1.5' ND 94.8 ND ND 32.4 9.37 21.6 10.8 0.05 ND ND ND^ 50.7 NA NA REC-3-1-1 07/12/2023 11:20 0.5 - 1.5' ND 94.4 ND ND 20.5 6.32 14.5 12.3 0.02 ND ND ND^ 31.5 NA ND REC-3-2-1 07/12/2023 11:50 6 - 6.5' 7.19 155 ND ND 50 13.9 33.2 11 0.03 ND ND ND^ 61.8 NA ND REC-3-3-1 07/12/2023 12:40 3.5 - 4.5' 31.5 2070 ND 13.6 174 22.5 1070 3210 4.35 ND ND ND^ 43.3 NA 0.00061 REC-3-4-1 07/12/2023 12:10 3 - 5' 7.36 174 ND ND 60.6 19.5 39.8 13 0.03 ND ND ND^ 70.9 NA 3.5E-07 REC-3-5-1 07/12/2023 13:30 1.5 - 2' ND 58.5 ND ND 33.9 10.3 10.2 10.5 ND ND ND ND^ 44.8 NA ND REC-3-6-1 07/12/2023 14:00 9 - 10' ND 164 ND 0.77 19.4 4.7 27.9 394 0.02 ND ND ND^ 17 NA 1.2E-07 REC-3-7-1 07/12/2023 14:10 3 - 3.5' ND 45.6 ND ND 10.9 3.92 9.37 4.98 0.23 ND ND ND^ 14.5 NA ND REC-4-1-1 07/11/2023 16:30 3 - 4' ND 19.5 NA ND 8.13 NA ND 2.55 ND ND ND NA NA NA NA REC-4-2-1 07/11/2023 16:40 0.5 - 1.5' ND 223 NA ND 9.78 NA 52.7 27.9 0.02 ND ND NA NA NA NA REC-4-3-1 07/12/2023 09:40 1 - 2' ND 29.9 NA ND 9.14 NA 2.6 5.77 ND ND ND NA NA NA NA REC-4-4-1 07/12/2023 10:00 1 - 2' 7.84 166 NA ND 8.86 NA 20.3 19.9 0.03 ND ND NA NA NA NA REC-4-5-1 07/12/2023 10:10 1 - 2' ND 73.4 NA ND 18 NA 8.34 7.06 ND ND ND NA NA NA NA REC-4-6-1 07/11/2023 16:20 1.5 - 2.5' ND 33.3 ND ND 17.1 4.98 11 3.62 ND ND ND ND^ 20 NA NA REC-4-7-1 07/11/2023 16:10 0.5 - 1' ND 103 ND ND 37 9.08 21.6 7.57 0.03 ND ND ND^ 40.3 NA NA REC-4-7-2 07/11/2023 16:15 3.5 - 4' 13.6 84.7 ND 4.91 104 11.9 14.4 6.94 0.71 ND ND ND^ 27.3 NA NA REC-4-8-1 07/11/2023 16:00 2 - 3' ND 129 ND ND 17.3 4.88 17.4 15.7 0.13 ND ND ND^ 21.8 NA NA REC-4-9-1 07/11/2023 15:50 1.5 - 2' ND 51.5 NA ND 20.90 NA 10.9 7.36 ND ND ND NA NA NA NA REC-4-10-1 07/11/2023 09:50 4 - 4.5' ND 120 NA ND 27.4 NA 110 23.5 0.19 ND ND NA NA NA NA REC-4-10-2 07/11/2023 10:00 3 - 3.5' ND 80.3 NA ND 24.8 NA 14.6 8.6 0.05 ND ND NA NA NA NA REC-4-11-1 07/11/2023 10:15 3.5 - 4.5' ND 193 NA ND 9.83 NA 28.2 54.9 0.1 ND ND NA NA NA NA REC-4-12-1 07/11/2023 10:40 3.5 - 4.5' ND 2580 NA ND 38.1 NA 701 602 0.04 ND ND NA NA NA NA REC-4-13-1 07/11/2023 11:00 3.5 - 4.5 ' 11.5 1150 NA 2.39 40 NA 208 714 0.08 ND ND NA NA NA NA REC-4-14-1 07/11/2023 11:20 4.5 - 5' ND 97.6 NA ND 34.7 NA 20.3 46.8 0.05 ND ND NA NA NA NA REC-4-15-1 07/11/2023 11:35 3 - 4' ND 978 NA ND 23.6 NA 306 706 0.08 ND ND NA NA NA NA REC-4-16-1 07/11/2023 11:55 2.5 - 3.5' 11.9 140 NA ND 9.99 NA 17.8 14.3 0.15 ND ND NA NA NA NA REC-4-17-1 07/11/2023 12:15 3.5 - 4.5' ND 215 NA ND 9.09 NA 23.8 28 0.12 ND ND NA NA NA NA REC-4-18-1 07/11/2023 13:00 3.5 - 4' ND 59 NA ND 12.3 NA 23.1 3400 0.07 ND ND NA NA NA NA REC-4-19-1 07/11/2023 13:25 3.5 - 4.5' 8.1 76.1 NA ND 8.99 NA 21.2 20.8 ND ND ND NA NA NA NA REC-4-20-1 07/11/2023 13:40 3.5 - 4.5' ND 204 NA ND 9.9 NA 12.8 6.67 ND ND ND NA NA NA NA REC-4-21-1 07/11/2023 14:00 3.5 - 4.5' 13 96.8 NA ND 10.8 NA 28.4 17.2 0.04 ND ND NA NA NA NA REC-4-22-1 07/11/2023 14:20 2.5 - 3.5' 8.03 242 NA ND 14.5 NA 58.2 43.4 0.02 ND ND NA NA NA NA REC-4-23-1 07/11/2023 14:40 2.5 - 3.5' 8.23 83.6 NA ND 10.7 NA 39.6 59.7 0.05 ND ND NA NA NA NA REC-4-24-1 07/11/2023 15:00 3.5 - 4.5' 9.03 127 NA ND 12.4 NA 37.4 5.6 ND ND ND NA NA NA NA REC-4-25-1 07/11/2023 15:20 3.5 - 4.5' ND 31.8 NA ND 7.86 NA 5.49 4.18 ND ND ND NA NA NA NA REC-4-26-1 07/11/2023 15:40 4.5 - 5' ND 132 NA ND 37.9 NA 9.73 9.21 ND ND ND NA NA NA NA REC-4-27-1 07/11/2023 16:00 4 - 5' 5.92 61.2 NA ND 16.5 NA 7.52 5.6 ND ND ND NA NA NA NA INCINERATOR 07/12/2023 12:50 2 - 3' ND 159 NA ND 15.9 NA 24.1 55.5 0.1 ND ND NA NA NA 2.1E-06 INCINERATOR-2 07/12/2023 12:20 2 - 3' ND 741 NA 1.68 22.1 NA 86 164 0.24 ND ND NA NA NA 2.2E-05 Notes:

*Assumes Chromium IV **Lower of inorganic and methyl mercury

Values indicated in red exceed MPCA Residential SRVs

A na ly te

S am pl e

R es ul ts

(m g/

K g)

Values indicated in red with highlight exceed MPCA Com/Ind Chronic SRV

PCBs = Polychlorinated biphenyls; MPCA = Minnesota Pollution Control Agency; SRV = Soil Reference Value; Res/Rec = Residential / Recreational; Com/Ind = Commercial / Industrial; NA = Not Analyzed; ND = Non Detect; ND^ = Not detected but the method detection limit (MDL) exceeded the SRV

Table 3 - Groundwater Sample Results

4th Street East, International Falls, Koochiching County, Minnesota

Sample ID Sample

Date Sample

Time

Well Depth (feet)

Depth to water (feet) A rs en ic

B ar iu m

B er yl liu m

C ad m iu m

C hr om iu m

C ob al t

C op pe r

Le ad

M er cu ry

Se le ni um

Si lv er

Th al liu m

Va na di um

SV

O

C s

A ce to ne

A ll ot he r

VO

C s

MN Dept. of Health Most Stringent HRL

- - - - - 2 0.00008 5E-04 0.1 - - - - 0.03 0.03 6E-04 - Various 3000 Various

REC-1/2-1-GW 07/12/2023 08:40 20' 19.30' NA NA NA NA NA NA NA NA NA NA NA NA NA NA 25.6 ND REC-3-4-GW 07/12/2023 15:40 6.05' 4.10' ND 0.3 ND ND 0.04 0.01 0.05 0.05 ND ND ND ND 0.05 ND ND ND…