COVER SHEET

SITE NAME: Iowa-Nebraska Light & Power Co

EPA ID No. NED986373678

Contact Persons

EPA Contact: Preston Law

U.S. Environmental Protection Agency (EPA), Region 7

11201 Renner Blvd.

Lenexa, Kansas 66219

(913) 551-7097

Documentation Record: David Zimmermann, Tetra Tech START

Pathways, Components, or Threats Not Scored

The air migration pathway, soil exposure pathway, and surface water migration pathway were not scored 

as part of this Hazard Ranking System (HRS) evaluation. These pathways or components were not 

included because a release to these media does not significantly affect the overall site score and because 

the ground water migration pathway alone produces an overall site score well above the minimum 

required for the site to qualify for inclusion on the National Priorities List (NPL). These pathways are of 

concern to EPA and may be evaluated during future investigations.
1

HRS DOCUMENTATION RECORD

Name of Site: Iowa-Nebraska Light & Power Co 

EPA Region: 7

Date Prepared: September, 2015

Street Address of Site*: 102-104 South 7th Street (Ref. 33)

City, County, State, ZIP: Norfolk, Madison County, Nebraska, 68701 (Ref. 33)

General Location in the State: The site is located in the northeastern portion of Nebraska, about 115 

miles northwest of the Omaha metropolitan area (Ref. 5, p. 5) (Figure 1).

Topographic Map: The location of the INL&P Site is shown on the Norfolk, Nebraska, 

Quadrangle, U.S. Geological Survey, 7.5-Minute Series Topographic 

Map (Ref. 3).

Latitude: 42o 01' 56.28" N. (Ref. 4)

Longitude: 97o 25' 01.30" W. (Ref. 4)

The latitude and longitude listed above is the approximate geographic location as measured from within 

the area of contaminated soil (Source 1), specifically within the gas holder on the facility property (Ref. 4; 

Figure 2 of this HRS documentation record). 

Scores

Ground Water Migration Pathway 81.60

Surface Water Migration Pathway Not scored

Soil Exposure Pathway Not scored

Air Migration Pathway Not scored

HRS SITE SCORE 40.80

* The street address, coordinates, and contaminant locations presented in this HRS documentation record 

identify the general area the site is located. They represent one or more locations EPA considers to be 

part of the site based on the screening information EPA used to evaluate the site for NPL listing. EPA 

lists national priorities among the known "releases or threatened releases" of hazardous substances; thus, 

the focus is on the release, not precisely delineated boundaries. A site is defined as where a hazardous 

substance has been "deposited, stored, disposed, or placed, or otherwise come to be located." Generally, 

HRS scoring and the subsequent listing of a release merely represent the initial determination that a 

certain area may need to be addressed under the Comprehensive Environmental Response, Compensation, 

and Liability Act. Accordingly, EPA contemplates that the preliminary description of facility boundaries 

at the time of scoring will be refined as more information is developed as to where the contamination has 

come to be located.
2

WORKSHEET FOR COMPUTING HRS SITE SCORE

S S2

1. Ground Water Migration Pathway Score (Sgw) 81.60 6,658.56

2a. Surface Water Overland/Flood Migration Component

(from Table 4-1, line 30)

Not Scored

2b. Ground Water to Surface Water Migration Component

(from Table 4-25, line 28)

Not Scored

2c. Surface Water Migration Pathway Score (Ssw)

Enter the larger of lines 2a and 2b as the pathway score.

Not Scored

3. Soil Exposure Pathway Score (Ss)

(from Table 5-1, line 22)

Not Scored

4. Air Migration Pathway Score (Sa)

(from Table 6-1, line 12)

Not Scored

5. Total of Sgw

2 + Ssw2 + Ss2 + Sa2 6,658.56

6. HRS Site Score

Divide the value on line 5 by 4 and take the square root

40.80
3

HRS TABLE 3-1 – GROUND WATER MIGRATION PATHWAY SCORESHEET

IOWA-NEBRASKA LIGHT & POWER SITE

Factor Categories and Factors

Maximum

Value

Value

Assigned

Likelihood of Release to an Aquifer:

1. Observed Release.................................................................................. 550 550

2. Potential to Release:

2a. Containment...................................................................................

2b. Net Precipitation.............................................................................

2c. Depth to Aquifer ............................................................................

2d. Travel Time....................................................................................

2e. Potential to Release [lines 2a(2b + 2c + 2d)].................................

10

10

5

35

500

NE

NE

NE

NE

NE

3. Likelihood of Release (higher of lines 1 and 2e).................................. 550 550

Waste Characteristics:

4. Toxicity/Mobility.................................................................................. a 10,000

5. Hazardous Waste Quantity ................................................................... a 10

6. Waste Characteristics............................................................................ 100 18

Targets:

7. Nearest Well ......................................................................................... 50 18

8. Population:

8a. Level I Concentrations...................................................................

8b. Level II Concentrations..................................................................

8c. Potential Contamination.................................................................

8d. Population (lines 8a + 8b + 8c) ......................................................

b

b

b

b

Not Scored

Not Scored

637

637

9. Resources.............................................................................................. 5 5

10. Wellhead Protection Area..................................................................... 20 20

11. Targets (lines 7 + 8d + 9 + 10) ............................................................. b 680

Ground Water Migration Score for an Aquifer:

12. Aquifer Score [(lines 3 x 6 x 11)/82,500]c

100 81.60

Ground Water Migration Pathway Score:

13. Pathway Score (Sgw), (highest value from line 12 for all aquifers 

evaluated)

100 81.60

a Maximum value applies to waste characteristics category

b Maximum value not applicable

c Do not round to nearest integer

NE Not Evaluated
4
5

REFERENCES

Reference

Number Description of the Reference

1. U.S. Environmental Protection Agency (EPA). Hazard Ranking System (HRS): Final 

Rule. Title 40 of the Code of Federal Regulations (CFR), Part 300; Federal Register, 

Volume 55, No. 241. Excerpt. On-Line Address: 

http://www.epa.gov/superfund/sites/npl/hrsres/rule/hrsrule.pdf. December 14, 1990. One 

page.

2. EPA. Superfund Chemical Data Matrix (SCDM). Excerpt. (Note: A complete copy of 

SCDM is available at On-Line Address: 

http://epa.gov/superfund/sites/npl/hrsres/tools/scdm.htm). June 2014. 25 pages.

3. U.S. Geological Survey (USGS). Norfolk (1976), Hoskins (1976), Madison (1976), Enola 

(1976). One sheet modified by Tetra Tech to show distance rings and municipal well 

locations.

4. Tetra Tech Inc. (Tetra Tech). Project Note Regarding Latitude and Longitude for the 

Iowa-Nebraska Light and Power (INL&P). Prepared by David Zimmermann, Program 

Manager. July 14, 2015. One page. 

5. Tetra Tech. Expanded Site Inspection Report for the Iowa-Nebraska Light & Power

Company Site. Task Order Number 013. March 30, 2001. 237 pages.

6. Ecology and Environment, Inc. (E&E). “Preliminary Assessment of Former Coal 

Gasification Site.” EPA Region 7 Field Investigation Team, TDD F-07-9007-013, 

Overland Park, Kansas. December 11, 1990. 14 pages.

7. HDR Engineering, Inc. “Site Investigation Report Former CENTEL, Inc., Manufactured 

Gas Plant Site, Norfolk, Nebraska.” October 1992. 175 pages.

8. CDM Federal Programs Corporation. “Site Status Determination and Review of Site 

Investigation Results as Conducted by HDR Engineering for Minnegasco Iowa/Nebraska 

Light and Power Company Norfolk, Nebraska.” Performed under EPA Contract 68-W9-

0021, Work Assignment Number 013-79ZZ. April 12, 1993. 26 pages.

9. Brown’s Directory of American Gas Companies, Selected Records for the Subject Site 

from 1907 through 1957. 36 pages.

10. State of Nebraska. “Well Logs for Municipal and Irrigation Wells in the Norfolk, 

Nebraska Area.” Well Registration Numbers, G-29258, G-29259, G-49057, G-49058, G49312, G-49313, G-59331, G-70112, G-70113, G-70114, G-70115, G-70116, G-7308, 

and G-72272. Multiple dates. 95 pages.

11. U. S. Department of Agriculture, Soil Conservation Service. 1984. “Soil Survey of 

Madison County, Nebraska.” 1984. Excerpt. 11 pages.

12. U.S. Census Bureau. “Norfolk (city) QuickFacts from the US Census Bureau,” Accessed 

on March 25, 2015. On-Line Address: 

http://quickfacts.census.gov/qfd/states/31/3134615.html. Two pages.
6

Reference

Number Description of the Reference

13. E&E. “Quality Assurance Project Plan for the Expanded Site Inspection Phase I at the 

Iowa-Nebraska Light and Power Company Site, Norfolk, Nebraska.” TDD S07-9903-

026, Overland Park, Kansas. February 14, 2000. 82 pages.

14. Reference Number Reserved. 

15. E&E. Memorandum with attachments: “Trip Report for Expanded Site 

Inspection/Remedial Investigation (ESI/RI) Field Work at the Iowa-Nebraska Light and 

Power Site, Norfolk, Nebraska.” TDD S07-9903-026. April 26, 2000. 10 pages.

16. Nebraska Health and Human Services (NHHS) Drinking Water Branch Water System 

details for the City of Norfolk Water System, Water System Number NE3111910. 

Accessed on 3/26/2015. Three pages.

17. NHHS Safe Drinking Information System. Public Water System Facilities and Public 

Water System Facilities Detail for the City of Norfolk Water System, Public Water 

System ID NE3111910. Accessed on September 27, 2004. 16 pages.

18. Brogden, Robert E., F. Butler Shaffer, and Richard A. Engberg. “Water Resources of 

Pierce County, Nebraska.” Nebraska Water Survey Paper Number 41. February 1976. 

Six pages.

19. Edison Electric Institute. “Handbook on Manufactured Gas Plant Sites.” Prepared for 

Utility Solid Waste Activities Group, Superfund Committee. Cover page, and portions of 

Chapter 3. September 1984. 32 pages.

20. E&E. Memorandum with attachments: “Trip Report for Site Reconnaissance: IowaNebraska Light and Power Co. Site, Norfolk, Nebraska.” TDD S07-9903-026. 

December 30, 1999. Seven pages.

21. State of Nebraska Well Registration System. Database printout of registered wells in 

Madison County, Nebraska, for Township 23 North, Range 1 West; and Township 24 

North Range 1 West. Dated July 18, 1990. Five pages. 

22. Reference Number Reserved. 

23. Reference Number Reserved.

24. Education Support Services, Nebraska Department of Education. “Statistics and Facts 

about Nebraska Schools, 2013-2014.” July 2015. 10 pages excerpted. Full report can be 

found at the found at the following Online Address:

http://drs.education.ne.gov/quickfacts/Pages/DistrictandSchoolInformation.aspx?RootFol

der=%2Fquickfacts%2FDistrict%20and%20School%20Information%2FStatistics%20and

%20Facts%20about%20Nebraska%20Schools&FolderCTID=0x012000308E78E48EF70

A4A969441D8F8732146&View={687391D6-980C-4AEA-BA91-FEF54153E36D}

25. NHHS Safe Drinking Water Branch. Water System Facility Detail Water System Facility 
7

Reference

Number Description of the Reference

Detail for the City of Norfolk Water System, Water System ID Number NE3111910. 

Accessed on July 29, 2015. 66 pages. 

26. 2013 Nebraska Higher Education Progress Report. Appendix 1. March 14. . On-Line 

Address for full report: 

http://www.ccpe.state.ne.us/publicdoc/ccpe/reports/progressReport/2012/default.asp. 

9 pages (excerpted and numbered).

27. City of Norfolk Nebraska Water Division Homepage. Water System Overview. 

Accessed on August 17, 2010. On-Line Address: http://www.ci.norfolk.ne.us/water/. 

One page.

28. Nebraska Department of Natural Resources, Registered Ground Water Wells Data 

Retrieval. Search for all wells in Township 24 North, Range 1 West. Processed 

November 28, 2001. 65 pages. 

29. State of Nebraska Source Water Assessment Program. Undated. The program document 

can be found at the following On-Line Address: 

http://deq.ne.gov/NDEQProg.nsf/OnWeb/SWAP. 39 pages. 

30. Terracon (Terracon). “Preliminary Subsurface Assessment Report, Unknown - Norfolk 

City Wells. Prepared for the Nebraska Department of Environmental Quality. UG No. 

031398-DB-1300. May 13, 1998.” Selected Figures. Seven pages.

31. Nebraska Department of Environmental Quality (NDEQ) - Ground Water Unit, Wellhead 

Protection Program. Letter from Bryant Reynolds, Compliance Specialist NDEQ to 

David Zimmermann, Tetra Tech EM Inc., regarding wellhead protection information with 

attached wellhead protection maps for community systems in and around Norfolk, 

Madison County, Nebraska. July 28, 2004. Nine pages.

32. NHHS Safe Drinking Water Information System. Water System Details for the Norfolk 

Regional Center, Public Water System Number NE3111901; Madison County SID #5, 

Water System Number NE3111912; Madison County SID #3-Sunny Meadow, Water 

System Number NE3111909; Covidien (former Kendal Company), Water System 

Number NE3150471; and Sleepy Hollow Acres Water System Number NE3111918. 

Accessed on July 30, 2015. Nine pages.

33. EPA. CERCLIS. Accessed on August 17, 2010. On-Line Address: 

http://oaspub.epa.gov/enviro/cerclis_web.report?pgm_sys_id=NED986373678. Two

pages. 

34. Black and Veatch. “Engineering Evaluation/Cost Evaluation (EECA) Site 

Characterization Report. Iowa-Nebraska Light and Power Site (Norfolk Former 

Manufactured Gas Plant Site). Prepared for Centel Corporation.” March 2010. 650 

pages. 

35. Northeast Community College, Norfolk Campus. Accessed on August 17, 2010. OnLine Address: http://www.northeast.edu/Norfolk/. One page. 
8

Reference

Number Description of the Reference

36. Tetra Tech Inc. Project Note Regarding Population Verification for Schools and Public 

Water System in Norfolk, Nebraska. Prepared by David Zimmermann, Project Manager. 

August 21, 2015. One page. 

37. Black and Veatch. “EE/CA Investigation Field Sampling Plan. Iowa-Nebraska Light and 

Power. Prepared for Centel Corporation.” June 2007. 56 pages. 

38. Black and Veatch. “Quality Assurance Project Plan. Prepared for Centel Corporation.” 

June 2007. 38 pages. 

39. EPA. “Administrative Settlement and Agreement and Order on Consent for Engineering 

Evaluation/Cost Analysis. In the Matter of Iowa-Nebraska Light & Power Site, Norfolk, 

Madison County, Nebraska, Aquila, Inc., and Centel Corporation, Respondents.” April 5, 

2007. 56 pages. 

40. EPA. “Memorandum Regarding Iowa-Nebraska Light and Power Manufactured Gas 

Plant Site, Norfolk, Madison County, Nebraska (SSID NO. A778), Administrative 

Settlement Agreement and Order on Consent for Engineering Evaluation and Cost 

Analysis.” From Barbara L. Peterson, Assistant Regional Counsel. To Cecilia Tapia, 

Director, Superfund Division. April 3, 2007. Two pages. 

41. NHHS Drinking Water Branch Water System Facilities Detail for the City of Norfolk 

Water System, Water System Number NE3111910. Accessed on August 17, 2010. Two

pages.

42. Agency for Toxic Substances and Disease Registry (ATSDR). Polycyclic Aromatic 

Hydrocarbons (PAHs): Public Health Statement. August 1995. Accessed on July 14, 

2010. On-Line Address: http://www.atsdr.cdc.gov/PHS/PHS.asp?id=120&tid=25. 

Seven pages. 

43. Tetra Tech. Record of Telephone Conversation Regarding the City of Norfolk Water 

Supply System. To Alicia Shultz, HRS Specialist. From Dennis Watts, Water 

Supervisor. July 28, 2010. Six pages. 

44. EPA. “Using Qualified Data to Document an Observed Release and Observed 

Contamination. EPA 540-F-94-028, OSWER 9285.7-14FS, PB94-963311.” November 

1996. 18 pages. 

45. EPA. HRS Analytical Results Supplement. ASR Number: 539. August 25, 2010. 208 

pages. 

46. Black and Veatch. “Soil Removal Summary Report. Norfolk, Nebraska, Former 

Manufactured Gas Plant Site. Prepared for Centel Corporation.” May 2015. 873 pages.

47. Tetra Tech. Project Note Regarding Population Verification for Large Employers Served 

by City of Norfolk Public Water System, Norfolk, Nebraska. Prepared by Jenna Mead, 

Tetra Tech, Inc. August 27, 2015. One page.
9 

Reference

Number Description of the Reference

48. Nebraska Public Power District. Community “Fast Facts” Profiles, Norfolk, Nebraska. 

2012. Accessed on August 27, 2015. On-Line Address: 

http://econdevtools.nppd.com/aedc/fastfacts.asp?city=Norfolk. 11 pages.
10

SITE DESCRIPTION

The Iowa-Nebraska Light & Power Co (INL&P) site consists of a contaminated soil source resulting from 

former gas manufacturing operations and an associated observed release of hazardous substances to 

shallow ground water as documented in monitoring wells (see sections 2.2 and 3.1.1 of the HRS 

documentation record). The primary targets scored for the site are municipal and community wells subject 

to potential contamination and located within 4 miles of the source (see section 3.3.2.4).

INL&P is located in downtown Norfolk, Madison County, Nebraska. The INL&P facility is located on a 

city block west of 7th Street between Norfolk and Madison Avenues and includes the alley running eastwest between 7th and 8th Streets. INL&P is roughly divided into two sections: the eastern portion north of 

the alley, as well as the northeastern portion of the area south of the alley (BH Parcel), is currently owned 

by Black Hills (BH); and the remaining southern portion of the property (NPPD Parcel), owned by 

Nebraska Public Power District (NPPD) (Refs. 34, pp. 7, 71, 72) (see Figure 1). The Norfolk Light and 

Fuel Company Manufactured Gas Plant was constructed between 1903 and 1909. A water gas process 

was used to manufacture gas. The Central West Service Company purchased INL&P in 1927. In 1931, 

INL&P purchased the property and switched to a carbureted water gas process. In February 1945, the 

property was purchased by the Central Electric and Gas Company, but ceased operations before the end 

of the decade (Refs. 6, p. 3; 34, p. 8). In 1941, NPPD acquired the property from Central Electric and Gas 

Company, excluding those portions of the property where manufactured gas plant (MGP) operations were 

conducted, which includes the BH Parcel (Ref. 34, pp. 8, 9). Minnegasco, Inc., purchased the BH parcel 

in 1976 and sold the northern portion to the People’s Natural Gas Company (subsequently known as 

UtiliCorp United and Aquila) (Refs. 6, p. 3; 34, pp. 8, 9). Black Hills purchased certain assets of Aquila, 

including the BH Parcel, in 2008 (Ref. 34, p. 9). 

Some of the waste resulting from the production of the manufactured gas, including coal tar, was sold. 

Some wastes were disposed of at the facility (Ref. 39, p. 7). Coal tar is primarily composed of polycyclic 

aromatic hydrocarbons (PAHs), phenolic compounds, light aromatic compounds, various inorganics and 

various sulfides (Refs. 8, p. 9; 39, pp. 6, 7). In December 1990, Ecology and Environment, Inc. (E&E),

conducted a preliminary assessment (PA) at INL&P to assess potential sources of contamination. The PA 

provided site-related background information, estimates of possible waste quantities produced, and a 

summary of nearby targets. No samples were collected as part of the PA (Ref. 6, pp. 1 to 4). The PA 

postulated that PAH and cyanide waste may have been disposed of to the ground (Ref. 6, p. 8). Specific 

waste disposal practices at the former facility are unknown (Ref. 8, p. 9). Sampling of soil near former 

facility operating units and ground water in the vicinity of the property has documented the release of 

hazardous substances to the environment as described below and throughout this HRS documentation 

record.

In June 1992, HDR Engineering Inc. (HDR) of Omaha, Nebraska, conducted a site investigation (SI) of 

INL&P for Minnegasco, Inc. Eighteen soil samples were collected from six soil borings, and four ground 

water samples were collected from three monitoring wells installed during field operations. The six 

borings referred to as NOR-101 through NOR-106, were located near former facility features to 

investigate the possibility that releases of associated wastes to soil had occurred in the past (Ref. 7, pp. 7, 

8). Both ground water and subsurface soil samples were found to contain PAH, aromatic volatile 

organics, and metals (Ref. 7, pp. 9, 10, 23, 30, 47, 88, 134 and Appendix H [Laboratory Reports]). 

Maximum concentrations of some PAHs detected in soil samples include naphthalene up to 1,400 

milligrams per kilogram (mg/kg), 2-methylnaphthalene up to 860 mg/kg, acenaphthene up to 340 mg/kg, 

phenanthrene up to 520 mg/kg, and pyrene up to 200 mg/kg. Maximum concentrations of volatile 

organic compounds (VOC) detected in soil samples include acetone up to 2.50 mg/kg, benzene up to 18 

mg/kg, ethylbenzene up to 70 mg/kg, toluene up to 16 mg/kg, and xylene (total) up to 47 mg/kg (Ref. 7, 

p. 23 and Appendix H). Maximum concentrations of PAHs detected in ground water samples include 
11

acenaphthene up to 0.550 milligrams per liter (mg/L); fluoranthene up to 0.210 mg/L; fluorene up to 

0.310 mg/L; 2-methylnaphthalene up to 2.70 mg/L; naphthalene up to 9.20 mg/L; phenanthrene up to 

0.900 mg/L; and pyrene up to 0.320 mg/L. Maximum concentrations of VOCs detected in ground water 

samples include benzene up to 3.20 mg/L, ethylbenzene up to 2.20 mg/L, toluene up to 1.90 mg/L, and 

xylene up to 2.40 mg/L (Ref. 7, p. 30 and Appendix H). 

In March 2001, Tetra Tech EM Inc. prepared an expanded site inspection (ESI) report for INL&P based 

on field activities performed by E&E in March 2000 (Refs. 5; 15, p. 1). During the ESI field work, 62 

soil, 20 direct push technology ground water, five municipal well, four private well, and one on-facility

monitoring well samples were collected and analyzed using the Superfund Technical Assistance and 

Response Team (START) mobile laboratory. Further, 32 soil samples, 15 direct push ground water 

samples, all the potable municipal and private well samples, and the on-facility monitoring well samples 

were submitted to the U.S. Environmental Protection Agency (EPA) Region 7 laboratory for confirmation 

analysis (Ref. 5, p. 13). Results from the EPA Region 7 laboratory analysis of on-facility subsurface soil 

samples documented the following PAHs at the indicated maximum concentrations: acenaphthene (240 

mg/kg); anthracene (33 mg/kg); benzo(a)anthracene (2.8 mg/kg); benzo(a)pyrene (2.3 mg/kg);

benzo(b)fluoranthene (3.0 mg/kg); benzo(g,h,i)perylene (0.94 mg/kg); benzo(k)fluoranthene (2.5 mg/kg);

chrysene (2.9 mg/kg); fluoranthene (140 J mg/kg ); fluorene (130 mg/kg); indeno(1,2,3-cd)pyrene (1.2 

mg/kg); 2-methylnaphthalene (410 mg/kg); naphthalene (600 mg/kg); phenanthrene (500 mg/kg); and 

pyrene (220 mg/kg) (Ref. 5, pp. 171, 180, 181, 183, 184). In addition, the following aromatic VOCs and 

their maximum concentrations were reported in on-facility soil samples: benzene (39 mg/kg), 

ethylbenzene (91 mg/kg), toluene (14 mg/kg), and total xylenes (130 mg/kg) (Ref. 5, pp. 165, 178, 179, 

182). The majority of these contaminants were also detected in on-facility ground water samples. One 

sample from an on-facility fixed monitoring well contained 11,455 micrograms per liter (μg/L) total PAH 

and 710 μg/L total aromatic hydrocarbons, including 250 μg/L of benzene (Ref. 5, pp. 35, 36, 158 - 160). 

During the ESI, 10 ground water wells were sampled and analyzed for low detection limit VOCs, metals, 

cyanide, and semivolatile organic compounds (SVOC). Specifically, five downgradient municipal wells 

(municipal wells 1 through 5) located approximately 0.25 mile from the INL&P, and an upgradient 

municipal well (municipal well 10), two shallow private domestic wells, a food processing well, and the 

Norfolk Rescue Mission well were sampled. Benzene was found in all five nearby municipal wells at 

concentrations ranging from 0.14 to 3.8 μg/L (Refs. 5, pp. 36, 130, 149, 155; 15, pp. 6, 9, 10). Two of the 

municipal wells have been closed because of the benzene contamination (Ref. 5, pp. 11, 12, 31). The City 

of Norfolk operates a total of 11 municipal wells that serve the entire population (Ref. 5, p. 31). Based on 

further investigations, the likely source of the benzene contamination found in the municipal wells is a 

leaking underground storage tank site that is currently undergoing remediation through a state program

(Ref. 34, pp. 12, 13, 74, 98 – 100, 111 – 112). 

In April of 2007, Aquila, Inc. and Centel Corporation entered into an Administrative Settlement 

Agreement and Order on Consent for Engineering Evaluation/Cost Analysis (EE/CA) with the U.S. 

Environmental Protection Agency (Ref. 39, p. 1). 

An EE/CA field investigation was conducted in November and December 2007, June and July 2009, and 

January 2010. The field investigation included advancing soil, electrical conductivity (EC), laser-induced 

fluorescence (LIF), and ground water probes; advancing soil borings; installing and developing 

monitoring wells; measuring ground water elevations; collecting samples of environmental media; and 

surveying. Sampling included collecting subsurface soil and ground water samples from direct-push 

probes and ground water samples from newly installed monitoring wells. A subsurface soil sample was 

also collected and submitted for geotechnical analysis. These field activities were designed to gather data 

to better define and characterize the subsurface geology and site hydrogeology and the approximate extent 
12

of soil, dense nonaqueous phase liquid (DNAPL), and dissolved-phase ground water contamination at 

INL&P (Ref. 34, p. 14). 

Eleven soil probes (SP-01 through SP-11) were advanced and subsurface soil samples collected for 

chemical analysis to supplement the existing EPA analytical data suitable for use in a baseline risk 

assessment. The samples were collected to define the approximate extent of soil contamination in the 

unsaturated zone (Ref. 34, pp. 15, 76). Fourteen ground water probes were advanced at INL&P, and three 

samples were collected from each probe (Ref. 34, pp. 17, 75). Monitoring wells were installed in soil 

borings. Two nested monitoring wells were installed at each location to monitor the upper and lower 

portions of the surficial aquifer (Ref. 34, pp. 18, 56, 75, 341 - 354). The soil and ground water samples 

confirm the release of VOCs and PAHs from former MGP operations to soil and ground water (Ref. 34, 

pp. 46, 47, 59, 60, and Appendices J [pp. 440-453] and K [pp. 454-541]). 

Between November 2013 and June 2014 removal activities occurred at the site as required by the 

Administrative Settlement Agreement and Order on Consent for Removal Action established with the 

EPA. Contaminated soil and highly concentrated residuals (source material) were excavated, 

consolidated, and transported off the property for disposal at the Butler County Landfill. (Ref. 46, p. 4) 

Soil was excavated to depths ranging from 2.5 to 17 feet below ground surface across the majority of the 

property. The entire Northern portion of the property and the western 2/3 of the southern portion of the 

property were excavated to the ground water table, approximately 16 to 17 feet below ground surface 

(Ref. 46, pp. 4, 29). Approximately 10,425 tons of contaminated soil/small debris were excavated and 

transported to the Butler County Landfill (Ref. 46, p. 4). The extent of soil removed is presented on 

Figures 3-1 and 3-2 of the soil removal summary report (Ref, 46, pp. 37, 38). Following soil removal, 

confirmation soil samples were collected from the base and walls of the excavation to evaluate residual 

soil contamination (Ref. 46, pp. 4, 37, 38). In the final wall confirmation samples, benzo(a) anthracene, 

benzo(a)pyrene, benzo(b)fluoranthene and indeno(1,2,3-cd)pyrene remained at concentrations exceeding 

cleanup levels in two or more samples (Ref. 46, p. 28). In the base samples, nine collected from 2 to 10 

feet bgs exceeded the benzo(a)pyrene cleanup level (Ref. 46, p. 31). 

The residents in the area surrounding INL&P, including the City of Norfolk, obtain drinking water 

supplies from ground water drawn from the alluvium and Niobrara chalk aquifer underlying INL&P and 

the surrounding area (Refs. 3; 10, pp. 1 -11, 34, 35; 11, pp. 3, 9; 17; 27; 41; 43). As documented in Table 

26 of this HRS documentation record, more than 35,900 persons obtain drinking water from the alluvium 

and Niobrara chalk aquifer. Also as documented in Table 26 of this HRS documentation record, one of 

the City of Norfolk’s supply wells is located within the 0.25 to 0.50 target distance categories of INL&P. 

This well is one of the 11 wells that supplies drinking water to more than 34,397 residents, students and 

workers, as documented in Section 3.3.2.4 of this HRS documentation record. 
Source No: 1

13 Source Characterization

2.2 SOURCE CHARACTERIZATION

2.2.1 SOURCE IDENTIFICATION

Name of source: Contaminated Soil associated with Facility Operations

Number of source: 1

Source Type: Contaminated Soil

Description and Location of Source (with reference to a map of the site):

Source 1 consists of contaminated soil associated with the past production of manufactured gas. The 

facility produced coal gas from 1902 until 1948 using a water-gas process (Ref. 39, p. 6). Generators 

produced a combustible gas using coke, steam, and oil products (Ref. 39, p. 6). As the gas cooled through 

the production process, coal tar would fall from suspension in the gas and become a waste product (Ref. 

39, p. 6). A scrubber was used to condense the gas (Ref. 39, p. 6). Coal tar was ultimately separated 

from the condensate water (Ref. 39, p. 6). Purifier boxes were used to remove sulfides and cyanides from 

the cool gas. Iron oxides were mixed with fluffing material (primarily wood chips, sawdust and 

corncobs) in the purifier boxes to provide for additional removal of water vapor and coal tar with the 

associated hydrogen sulfide and cyanide (Ref. 39, p. 6). After the gas was manufactured, it was stored in 

gas holders. Coal tar residuals were also present in the gas holders (Ref. 39, p. 6).

Some of the waste resulting from the production of the manufactured gas, including coal tar, was sold. 

Some wastes were disposed of at the facility (Ref. 39, p. 7). Coal tar is primarily composed of polycyclic 

aromatic hydrocarbons, phenolic compounds, light aromatic compounds, various inorganics and various 

sulfides (Ref. 39, pp. 6, 7). In December 1990, Ecology and Environment, Inc. (E&E), completed a 

preliminary assessment (PA) at INL&P to assess potential sources of contamination. The PA provided 

site-related background information, estimates of possible waste quantities produced, and a summary of 

nearby targets. No samples were collected as part of the PA (Ref. 6, pp. 1 to 4). The PA postulated that 

PAH and cyanide waste may have been disposed of to the ground (Ref. 6, p. 8). In June 1992, HDR

Engineering Inc. (HDR) of Omaha, Nebraska, conducted a site investigation (SI) of INL&P for 

Minnegasco, Inc. (Ref. 7, pp. 1, 47, 88, 134). Eighteen soil samples were collected from six soil borings, 

and four ground water samples were collected from three monitoring wells installed during field 

operations (Ref. 7, pp. 7, 8, 47, 88, 134). The six borings referred to as NOR-101 through NOR-106, 

were located near former facility features to investigate the possibility that releases of associated wastes 

to soil had occurred in the past (Ref. 7, pp. 7, 8). PAHs were detected in soil samples from borings NOR101, NOR-102, NOR-103, NOR-104, NOR-105 and NOR-106 consistent with coal tar. (Ref. 7, p. 23)

Two sampling events have occurred at INL&P that are used to characterize this source. Analytical results 

for soil samples from the 2000 ESI and the 2007 soil sampling conducted as part of an EE/CA were used 

to identify residual contamination in soil from processes associated with the production of manufactured 

gas (Refs. 13, pp. 17 - 19, 24; 34, pp. 6, 14, 15, 16). During the ESI, soil samples were collected at or 

near the following former MGP features: gas purifiers, condenser, scrubber, generator, and various 

10,000-cubic-foot gas holders as well as additional locations to the south to define the approximate extent 

of contamination (Refs. 5, p. 17; 7, pp. 7, 8). The text below provides additional information on the 

history of the property and various investigations. It also introduces the results of the soil sampling. Soil 

sample locations are presented on Figure 2.
Source No: 1

14 Source Characterization

During the ESI, 32 soil samples were submitted to the EPA Region 7 laboratory for analysis. Results 

from the EPA Region 7 laboratory analysis of subsurface soil samples documented the following PAHs at 

the indicated maximum concentrations: acenaphthene (240 milligrams per kilogram [mg/kg]); anthracene 

(33 mg/kg); benzo(a)anthracene (2.8 mg/kg); benzo(a)pyrene (2.3 mg/kg); benzo(b)fluoranthene (3.0 

mg/kg); benzo(g,h,i)perylene (0.94 mg/kg); benzo(k)fluoranthene (2.5 mg/kg); chrysene (2.9 mg/kg);

fluoranthene (140 J mg/kg ); fluorene (130 mg/kg); indeno(1,2,3-cd)pyrene (1.2 mg/kg); 2-

methylnaphthalene (410 mg/kg); naphthalene (600 mg/kg); phenanthrene (500 mg/kg); and pyrene (220 

mg/kg) (Ref. 5, pp. 171, 180, 181, 183, 184). In addition, the following aromatic VOCs, and their 

maximum concentrations, were reported in soil samples: benzene (39 mg/kg), ethylbenzene (91 mg/kg), 

toluene (14 mg/kg), and total xylenes (130 mg/kg) (Ref. 5, pp. 165, 178, 179, 182). 

Between November 2013 and June 2014 removal activities occurred as required by the Administrative 

Settlement Agreement and Order on Consent for Removal Action established with the EPA. 

Contaminated soil and highly concentrated residuals (source material) were excavated, consolidated, and 

transported off the property for disposal (Ref. 46, p. 4). Soil was excavated to depths ranging from 2.5 to 

17 feet below ground surface across the majority of the property (Ref. 46, p. 4, 29). Approximately

10,425 tons of contaminated soil/small debris were excavated and transported to the Butler County 

Landfill. The extent of soil removed is presented on Figures 3-1 and 3-2 of the soil removal summary 

report (Ref, 46, pp. 37, 38). Following soil removal, confirmation soil samples were collected from the 

base and walls of the excavation to evaluate residual soil contamination (Ref. 46, pp. 4, 37, 38). In the 

final wall confirmation samples, benzo(a) anthracene, benzo(a)pyrene, benzo(b)fluoranthene and 

indeno(1,2,3-cd)pyrene remained at concentrations exceeding cleanup levels in two or more samples 

(Ref. 46, p. 28), documenting that contamination still remains in site soils. In addition, releases from the 

source to shallow ground water were not addressed as part of the removal activities.
Source No: 1 

15 Source Characterization
Source No: 1

16 Source Characterization

2.2.2 HAZARDOUS SUBSTANCES ASSOCIATED WITH THE SOURCE

The hazardous substances associated with the area of contaminated soil (Source 1) at INL&P are 

identified using analytical data for soil from the 2000 ESI and the 2007 EE/CA. The analytical data used 

to characterize Source 1 are described separately in the sections below. 

2000 Expanded Site Inspection Soil Samples:

ESI field activities occurred between March 19 and 25, 2000, and were completed in accordance with the 

site-specific quality assurance project plan (QAPP) (Refs. 5, pp. 1, 13; 13). During the ESI field work, 62 

soil samples were collected and analyzed using the mobile laboratory in accordance with the START 

Mobile Laboratory Program (MLP) QAPP (Ref. 5, pp. 13, 205-209). Thirty-two confirmatory soil 

samples were submitted to the EPA Region 7 laboratory for confirmation analysis (Ref. 5, pp. 13, 130, 

131). Appendices B and C of Reference 5 provide copies of the field sheets, and analytical data for soil 

samples collected (Ref. 5, pp. 85-118, 130, 131, 163-165, 171- 194). Samples collected by START were 

analyzed by the EPA Region 7 laboratory under analytical services request (ASR) number 539, activity 

number TJC13 (Ref. 5, pp. 128-131). The laboratory analyzed the samples in accordance with EPA 

Region 7 Standard Operating Procedure (SOP) 1640.1A, EPA Region 7 Laboratory QAPP (Ref. 13, p. 

29). SVOCs were analyzed in accordance the EPA Region 7 SOP 3230.2B for extraction and analysis of 

water and solids for SVOCs dated February 1995. The VOCs were analyzed in accordance with EPA 

Region 7 SOP 3230.1C, Gas Chromatography/Mass Spectrometry (GC/MS) Analysis for VOCs, dated 

October 1993. The metals were analyzed in accordance EPA Region 7 SOP 3122.2B, analysis for metals 

by TJA ICAP 61, April 1995 (Ref. 13, p. 31). The ASR for the sample analysis is provided on page 80 of 

Reference 13. The data were validated in accordance with procedures outlined in Section 6.5 of the 

QAPP (Refs. 13, p. 34; 5, p. 132). The chain-of custody forms for the samples collected during the ESI 

and sent to the EPA Region 7 laboratory are provided as Appendix B of Reference 5, pages 124 to 127. 

The logbook notes documenting sampling are provided as Appendix D of Reference 5, pages 211-237. 

A modified grid system was established in the southern portion of the INL&P property to identify 

possible soil contamination from MGP operations. Surface and subsurface soil samples were collected 

within the grid. Soil sampling locations on the northern portion of the property were biased toward MGP 

features, such as gas holders (Ref. 5, pp. 13, 14). 

The lithology of each borehole and sample depth were noted during the soil sampling to characterize the 

soil and near-surface lithology. The visual inspection, organic vapor analyzer readings of the borehole 

material, and initial field analytical data were used to select the depths of samples collection across the 

study area. Based on those data and observations, soil samples generally were collected within the 

intervals from 0 to 4 feet below ground surface (bgs), 7 to 11 feet bgs, and 13 to 16 feet bgs (Ref. 5, p. 

14). 

The locations of the soil samples on the property are shown in Figure 3-1, page 17, of Reference 5. 

Sampling locations off of the facility, including the background soil sampling locations, are shown in 

Figure 3-2, page 18, of Reference 5. Reference 15 summarizes the ESI field activities. 

2000 Expanded Site Inspection - Background Concentrations: 

During the ESI, seven designated background samples were collected at various depths (from 0 to 2 

inches to 13 to 14 feet bgs) from a single direct push technology borehole location designated as GP-8.

(Ref. 5, pp. 23, 131). All of these samples were analyzed by the EPA Region 7 laboratory (Ref. 5, pp. 14-

16, 110-116). The location of the background sample is approximately three city blocks northwest and 

upgradient of the facility (Ref. 5, p. 18). The locations of the background and release samples are shown 
Source No: 1

17 Source Characterization

in Figure 3-2, page 18, of Reference 5. The background and release samples were collected during the 

same period of time using the same sampling procedures (Ref. 5, p. 13), were analyzed using the same 

analytical methods (Ref. 5, pp. 14, 130-132), and were collected from the same soil association (Refs. 5, 

p. 18; 11, pp. 9- 11). In addition to the soil samples collected from GP-8, several other soil samples 

collected from the facility were analyzed and did not contain hazardous substances including SB-1, 

located north of the former facility and SB-28 located west of the former facility and north of a 

transformer yard (Ref. 5, pp 15, 17).

As documented in Tables 1 and 3 below, the ESI background and release samples were collected from the 

same relative depths. Field sheets were used to document sample locations, collection times, and dates. 

Field sheets are referenced in Table 1 and 3. Table 1 provides a summary of background soil samples and 

sampling dates. Table 2 summarizes the concentrations of hazardous substances detected in the 

background soil samples. 

TABLE 1

ESI BACKGROUND SOIL SAMPLES

Sample Identification 

(depth)

Laboratory 

Sample Number Sample Medium Date Reference

GP-8 (0-2") 226 Soil 3/24/00 5, pp. 18, 59, 110, 126, 131, 

229, 233

GP-8 (1-2') 227 Soil 3/23/00 5, pp. 18, 59, 111, 126, 131, 

229

GP-8 (3-4') 228 Soil 3/23/00 5, pp. 18, 59, 112, 126, 131, 

229

GP-8 (4-7') 229 Soil 3/23/00 5, pp. 18, 59, 113, 126, 131, 

229

GP-8 (8-10') 230 Soil 3/23/00 5, pp. 18, 59, 114, 126, 131, 

229

GP-8 (11-13') 231 Soil 3/23/00 5, pp. 18, 59, 115, 126, 131, 

229

GP-8 (13-14') 232 Soil 3/23/00 5, pp. 18, 59, 116, 126, 131, 

229

SB-1 (11-13’) 211 Soil 3/21/00 5, pp. 17, 95, 124, 130

SB-28 (13-14’) 216 Soil 3/22/00 5, pp. 17, 100, 124, 130

Notes:

" Inches

' Feet

GP Geoprobe
Source No: 1

18 Source Characterization

TABLE 2

ESI BACKGROUND SOIL CONCENTRATIONS

Hazardous 

Substance

Sample 

Identification

(sample depth)

Laboratory

Sample

Number

Hazardous 

Substance 

Concentration 

(μg/kg)

Sample 

Quantitation 

Limit (SQL)* 

(μg/kg) Reference 5 Reference 45

AcenaphtheneGP-8 (0-2")

GP-8 (1-2')

GP-8 (3-4')

GP-8 (4-7')

GP-8 (8-10')

GP-8 (11-13')

GP-8 (13-14')

SB-1 (11-13’)

SB-28 (13-14’)

226

227

228

229

230

231

232

211

216

410 U

400 U

450 U

450 U

450 U

470 U

520 U

440 U

450 U

410

400

450

450

450

470

520

440

450

p. 186

p. 186

p. 189

p. 189

p. 189

p. 189

p. 192

p. 174

p. 180

p. 170

p. 173

p. 176

p. 179

p. 182

p. 185

p. 188

p. 126

p. 140

Anthracene GP-8 (0-2")

GP-8 (1-2')

GP-8 (3-4')

GP-8 (4-7')

GP-8 (8-10')

GP-8 (11-13')

GP-8 (13-14') 

SB-1 (11-13’)

SB-28 (13-14’)

226

227

228

229

230

231

232

211

216

410 U

400 U

450 U

450 U

450 U

470 U

520 U

440 U

450 U

410

400

450

450

450

470

520

440

450

p. 186

p. 186

p. 189

p. 189

p. 189

p. 189

p. 192

p. 174

p. 180

p. 170

p. 173

p. 176

p. 179

p. 182

p. 185

p. 188

p. 126

p. 140

Benzo(a)

anthracene

GP-8 (0-2")

GP-8 (1-2')

GP-8 (3-4')

GP-8 (4-7')

GP-8 (8-10')

GP-8 (11-13')

GP-8 (13-14') 

SB-1 (11-13’)

SB-28 (13-14’)

226

227

228

229

230

231

232

211

216

410 U

400 U

450 U

450 U

450 U

470 U

520 U

440 U

450 U

410

400

450

450

450

470

520

440

450

p. 186

p. 186

p. 189

p. 189

p. 189

p. 189

p. 192

p. 174

p. 180

p. 170

p. 173

p. 176

p. 179

p. 182

p. 185

p. 188

p. 126

p. 141

Benzo(a)

pyrene

GP-8 (0-2")

GP-8 (1-2')

GP-8 (3-4')

GP-8 (4-7')

GP-8 (8-10')

GP-8 (11-13')

GP-8 (13-14') 

SB-1 (11-13’)

SB-28 (13-14’)

226

227

228

229

230

231

232

211

216

410 U

400 U

450 U

450 U

450 U

470 U

520 U

440 U

450 U

410

400

450

450

450

470

520

440

450

p. 186

p. 186

p. 189

p. 189

p. 189

p. 189

p. 192

p. 174

p. 180

p. 170

p. 173

p. 176

p. 179

p. 182

p. 185

p. 188

p. 126

p. 141

Benzo(b)

fluoranthene

GP-8 (0-2")

GP-8 (1-2')

GP-8 (3-4')

GP-8 (4-7')

GP-8 (8-10')

GP-8 (11-13')

GP-8 (13-14') 

SB-1 (11-13’)

SB-28 (13-14’)

226

227

228

229

230

231

232

211

216

410 U

400 U

450 U

450 U

450 U

470 U

520 U

440 U

450 U

410

400

450

450

450

470

520

440

450

p. 186

p. 186

p. 189

p. 189

p. 189

p. 189

p. 192

p. 174

p. 180

p. 170

p. 173

p. 176

p. 179

p. 182

p. 185

p. 188

p. 126

p. 141
Source No: 1

19 Source Characterization

TABLE 2

ESI BACKGROUND SOIL CONCENTRATIONS

Hazardous 

Substance

Sample 

Identification

(sample depth)

Laboratory

Sample

Number

Hazardous 

Substance 

Concentration 

(μg/kg)

Sample 

Quantitation 

Limit (SQL)* 

(μg/kg) Reference 5 Reference 45

Benzo(g,h,i)

perylene

GP-8 (0-2")

GP-8 (1-2')

GP-8 (3-4')

GP-8 (4-7')

GP-8 (8-10')

GP-8 (11-13')

GP-8 (13-14') 

SB-1 (11-13’)

SB-28 (13-14’)

226

227

228

229

230

231

232

211

216

410 U

400 U

450 U

450 U

450 U

470 U

520 U

440 U

450 U

410

400

450

450

450

470

520

440

450

p. 186

p. 186

p. 189

p. 189

p. 189

p. 189

p. 192

p. 174

p. 180

p. 170

p. 173

p. 176

p. 179

p. 182

p. 185

p. 188

p. 126

p. 141

Benzo(k)

fluoranthene

GP-8 (0-2")

GP-8 (1-2')

GP-8 (3-4')

GP-8 (4-7')

GP-8 (8-10')

GP-8 (11-13')

GP-8 (13-14') 

SB-1 (11-13’)

SB-28 (13-14’)

226

227

228

229

230

231

232

211

216

410 U

400 U

450 U

450 U

450 U

470 U

520 U

440 U

450 U

410

400

450

450

450

470

520

440

450

p. 186

p. 186

p. 189

p. 189

p. 189

p. 189

p. 192

p. 174

p. 180

p. 170

p. 173

p. 176

p. 179

p. 182

p. 185

p. 188

p. 126

p. 141

Chrysene GP-8 (0-2")

GP-8 (1-2')

GP-8 (3-4')

GP-8 (4-7')

GP-8 (8-10')

GP-8 (11-13')

GP-8 (13-14') 

SB-1 (11-13’)

SB-28 (13-14’)

226

227

228

229

230

231

232

211

216

410 U

400 U

450 U

450 U

450 U

470 U

520 U

440 U

450 U

410

400

450

450

450

470

520

440

450

p. 187

p. 187

p. 190

p. 190

p. 190

p. 190

p. 193

p. 175

p. 181

p. 170

p. 173

p. 176

p. 179

p. 182

p. 185

p. 188

p. 126

p. 141

Fluoranthene GP-8 (0-2")

GP-8 (1-2')

GP-8 (3-4')

GP-8 (4-7')

GP-8 (8-10')

GP-8 (11-13')

GP-8 (13-14') 

SB-1 (11-13’)

SB-28 (13-14’)

226

227

228

229

230

231

232

211

216

410 U

400 U

450 U

450 U

450 U

470 U

520 U

440 U

450 U

410

400

450

450

450

470

520

440

450

p. 187

p. 187

p. 190

p. 190

p. 190

p. 190

p. 193

p. 175

p. 181

p. 171

p. 174

p. 177

p. 180

p. 183

p. 186

p. 188

p. 126

p. 141

Fluorene GP-8 (0-2")

GP-8 (1-2')

GP-8 (3-4')

GP-8 (4-7')

GP-8 (8-10')

GP-8 (11-13')

GP-8 (13-14') 

SB-1 (11-13’)

SB-28 (13-14’)

226

227

228

229

230

231

232

211

216

410 U

400 U

450 U

450 U

450 U

470 U

520 U

440 U

450 U

410

400

450

450

450

470

520

440

450

p. 187

p. 187

p. 190

p. 190

p. 190

p. 190

p. 193

p. 175

p. 181

p. 171

p. 174

p. 177

p. 180

p. 183

p. 185

p. 188

p. 126

p. 141
Source No: 1

20 Source Characterization

TABLE 2

ESI BACKGROUND SOIL CONCENTRATIONS

Hazardous 

Substance

Sample 

Identification

(sample depth)

Laboratory

Sample

Number

Hazardous 

Substance 

Concentration 

(μg/kg)

Sample 

Quantitation 

Limit (SQL)* 

(μg/kg) Reference 5 Reference 45

Indeno(1,2,3-

cd)pyrene

GP-8 (0-2")

GP-8 (1-2')

GP-8 (3-4')

GP-8 (4-7')

GP-8 (8-10')

GP-8 (11-13')

GP-8 (13-14') 

SB-1 (11-13’)

SB-28 (13-14’)

226

227

228

229

230

231

232

211

216

410 U

400 U

450 U

450 U

450 U

470 U

520 U

440 U

450 U

410

400

450

450

450

470

520

440

450

p. 187

p. 187

p. 190

p. 190

p. 190

p. 190

p. 193

p. 175

p. 181

p. 171

p. 174

p. 177

p. 180

p. 183

p. 186

p. 189

p. 127

p. 141

2-MethylnaphthaleneGP-8 (0-2")

GP-8 (1-2')

GP-8 (3-4')

GP-8 (4-7')

GP-8 (8-10')

GP-8 (11-13')

GP-8 (13-14') 

SB-1 (11-13’)

SB-28 (13-14’)

226

227

228

229

230

231

232

211

216

410 U

400 U

450 U

450 U

450 U

470 U

520 U

440 U

450 U

410

400

450

450

450

470

520

440

450

p. 187

p. 187

p. 190

p. 190

p. 190

p. 190

p. 193

p. 175

p. 181

p. 171

p. 174

p. 177

p. 180

p. 183

p. 186

p. 189

p. 127

p. 141

Naphthalene GP-8 (0-2")

GP-8 (1-2')

GP-8 (3-4')

GP-8 (4-7')

GP-8 (8-10')

GP-8 (11-13')

GP-8 (13-14') 

SB-1 (11-13’)

SB-28 (13-14’)

226

227

228

229

230

231

232

211

216

410 U

400 U

450 U

450 U

450 U

470 U

520 U

440 U

450 U

410

400

450

450

450

470

520

440

450

p. 187

p. 187

p. 190

p. 190

p. 190

p. 190

p. 193

p. 175

p. 181

p. 171

p. 174

p. 177

p. 180

p. 183

p. 186

p. 189

p. 127

p. 141

Phenanthrene GP-8 (0-2")

GP-8 (1-2')

GP-8 (3-4')

GP-8 (4-7')

GP-8 (8-10')

GP-8 (11-13')

GP-8 (13-14') 

SB-1 (11-13’)

SB-28 (13-14’)

226

227

228

229

230

231

232

211

216

410 U

400 U

450 U

450 U

450 U

470 U

520 U

440 U

450 U

410

400

450

450

450

470

520

440

450

p. 187

p. 187

p. 190

p. 190

p. 190

p. 190

p. 193

p. 175

p. 181

p. 171

p. 174

p. 177

p. 180

p. 183

p. 186

p. 189

p. 127

p. 142

Pyrene GP-8 (0-2")

GP-8 (1-2')

GP-8 (3-4')

GP-8 (4-7')

GP-8 (8-10')

GP-8 (11-13')

GP-8 (13-14') 

SB-1 (11-13’)

SB-28 (13-14’)

226

227

228

229

230

231

232

211

216

410 U

400 U

450 U

450 U

450 U

470 U

520 U

400 U

450 U

410

400

450

450

450

470

520

440

450

p. 187

p. 187

p. 190

p. 190

p. 190

p. 190

p. 193

p. 175

p. 181

p. 171

p. 174

p. 177

p. 180

p. 183

p. 186

p. 189

p. 127

p. 142
Source No: 1 

21 Source Characterization

TABLE 2

ESI BACKGROUND SOIL CONCENTRATIONS

Hazardous Sample 

Sample Laboratory Substance Quantitation 

Hazardous Identification Sample Concentration Limit (SQL)* 

Substance (sample depth) Number (μg/kg) (μg/kg) Reference 5 Reference 45

Notes:

* The SQL is the laboratory's contract required quantitation limit (CRQL), for analyses performed by CLP, or the 

laboratory's reporting limit (RL), for other laboratories, for that analyte with any dilution factor, volume adjustment, or percent 

solids for that sample analysis taken into account (Ref. 45, p. 1). 

" Inches

' Feet

μg/kg Micrograms per kilogram or parts per billion

GP Geoprobe

U Not detected at or above the reporting limit shown (Ref. 5, p. 129)

2000 Expanded Site Inspection - Source Samples:

Soil samples collected from INL&P that contained concentrations of hazardous substances that are at 

concentrations significantly above background concentrations are presented in Table 3 below. These 

samples were identified as soil borings with the sample identification starting with “SB” and were 

collected using a direct push technology rig (Refs. 13, pp. 18, 19; 15, pp. 1, 3). The concentrations of 

hazardous substances detected in the source samples are summarized in Table 4. 

TABLE 3

ESI SUMMARY OF SOURCE 1 SAMPLES

Sample Identification

Laboratory Sample 

Number Sample Medium Date Reference

SB-18 (1-2') 221 Soil 03/22/00 5, pp. 17, 105, 124, 131

SB-19 (1-2') 223 Soil 03/22/00 5, pp. 17, 107, 125, 131

SB-22 (3-4') 218 Soil 03/21/00 5, pp. 17, 102, 124, 130

SB-22 (16-18') 214 Soil 03/21/00 5, pp. 17, 98, 124, 130

SB-23 (3-4') 219 Soil 03/21/00 5, pp. 17, 103, 124, 131

SB-23 (7-11') 217 Soil 03/21/00 5, pp. 17, 101, 124, 130

SB-5 (4-7') 202 Soil 03/21/00 5, pp. 17, 86, 124, 130

SB-5 (11-13’) 203 Soil 03/21/00 5, pp. 17, 87, 124, 130 

SB-3 (8-10') 206 Soil 03/21/00 5, pp. 17, 90, 124, 130

SB-3 (13-16') 205 Soil 03/21/00 5, pp. 17, 89, 124, 130

SB-25 (13-14') 213 Soil 03/22/00 5, pp. 17, 97, 124, 130

SB-2 (13-17') 212 Soil 03/21/00 5, pp. 17, 96, 124, 130

SB-6 (14-16') 209 Soil 03/22/00 5, pp. 17, 93, 124, 130

Notes:

' Feet

SB Soil boring
Source No: 1

22 Source Characterization

TABLE 4

ESI SOURCE 1 SOIL CONCENTRATIONS

Hazardous 

Substance

Sample 

Identification

(sample depth)

Laboratory 

Sample

Number

Background 

Sample A

(see Table 2)

Background 

Conc. B

(see Table 2)

(μg/kg)

Hazardous 

Substance 

Conc.

(μg/kg)

Sample 

Quantitation 

Limit 

(SQL)*(μg/k

g) Ref. 5 Ref. 45

Acenaphthene SB-22 (3-4')

SB-22 (16-18')

SB-23 (3-4')

SB-23 (7-11')

SB-5 (4-7')

SB-3 (8-10)

SB-3 (13-16')

SB-2 (13-17')

SB-6 (14-16')

218

214

219

217

202

206

205

212

209

GP-8 (3-4’)

GP-8 (13-14’)

GP-8 (3-4’)

GP-8 (8-10’)

GP-8 (4-7’)

GP-8 (8-10’)

GP-8 (13-14’)

GP-8 (13-14’)

GP-8 (13-14’)

450 U

520 U

450 U

450 U

450 U

450 U

520 U

520 U

520 U

84,000

180,000

13,000

240,000

4,100

78,000

42,000

38,000

54,000

54,000

120,000

8,800

120,000

1,700

25,000

13,000

13,000

26,000

p. 180

p. 177

p. 180

p. 180

p. 163

p. 171

p. 171

p. 177

p. 174

p. 146

p. 135

p. 149

p. 143

p. 101

p. 113

p. 110

p. 129

p. 120

Anthracene SB-23 (3-4')

SB-5 (4-7')

SB-3 (8-10)

SB-3 (13-16')

SB-2 (13-17')

219

202

206

205

212

GP-8 (3-4’)

GP-8 (4-7’)

GP-8 (8-10’)

GP-8 (13-14’)

GP-8 (13-14’)

450 U

450 U

450 U

520 U

520 U

9,800

1,900

33,000

20,000

15,000

8,800

1,700

25,000

13,000

13,000

p. 180

p. 163

p. 171

p. 171

p. 177

p. 149

p. 101

p. 113

p. 110

p. 129

Benzo(a)

anthracene

SB-18 (1-2')

SB-19 (1-2')

221

223

GP-8 (1-2’)

GP-8 (1-2’)

400 U

400 U

2,800

790

1,700

510

p. 183

p. 183

p. 155

p. 161

Benzo(a)

Pyrene

SB-18 (1-2')

SB-19 (1-2')

221

223

GP-8 (1-2’)

GP-8 (1-2’)

400 U

400 U

2,300

1,100

1,700

510

p. 183

p. 183

p. 155

p. 161

Benzo(b)

fluoranthene

SB-18 (1-2')

SB-19 (1-2')

221

223

GP-8 (1-2’)

GP-8 (1-2’)

400 U

400 U

3,000

2,400

1,700

510

p. 183

p. 183

p. 155

p. 161

Benzo(g,h,i)

perylene

SB-19 (1-2') 223 GP-8 (1-2’) 400 U 940 510 p. 183 p. 161

Benzo(k)

fluoranthene

SB-19 (1-2') 223 GP-8 (1-2’) 400 U 2,500 510 p. 183 p. 161

Chrysene SB-18 (1-2') 221 GP-8 (1-2’) 400 U 2,900 1,700 p. 184 p. 156

Fluoranthene SB-18 (1-2')

SB-23 (3-4')

221

219

GP-8 (1-2’)

GP-8 (3-4’)

400 U

450 U

6,900

12,000

1,700

8,800

p. 184

p. 181

p. 156

p. 150

Fluorene SB-22 (3-4')

SB-23 (3-4')

SB-23 (7-11')

SB-5 (4-7')

SB-3 (8-10)

SB-3 (13-16')

SB-2 (13-17')

218

219

217

202

206

205

212

GP-8 (1-2’)

GP-8 (3-4’)

GP-8 (8-10’)

GP-8 (4-7’)

GP-8 (8-10’)

GP-8 (13-14’)

GP-8 (13-14’)

400 U

450 U

450 U

450 U

450 U

520 U

520 U

57,000

10,000

130,000

1,900

29,000

18,000

13,000

54,000

8,800

120,000

1,700

25,000

13,000

13,000

p. 181

p. 181

p. 181

p. 164

p. 172

p. 172

p. 178

p. 147

p. 150

p. 144

p. 102

p. 114

p. 111

p. 129

2-MethylnaphthaleneSB-19 (1-2')

SB-22 (3-4')

SB-22 (16-18')

SB-23 (3-4')

SB-23 (7-11')

SB-25 (13-14')

SB-5 (4-7')

SB-3 (8-10)

SB-3 (13-16')

SB-2 (13-17')

SB-6 (14-16')

223

218

214

219

217

213

202

206

205

212

209

GP-8 (1-2’)

GP-8 (3-4’)

GP-8 (13-14’)

GP-8 (3-4’)

GP-8 (8-10’)

GP-8 (13-14’)

GP-8 (4-7’)

GP-8 (8-10’)

GP-8 (13-14’)

GP-8 (13-14’)

GP-8 (13-14’)

400 U

450 U

520 U

450 U

450 U

520 U

450 U

450 U

520 U

520 U

520 U

610

63,000

390,000

36,000

410,000

13,000

3,200

130,000

45,000

47,000

100,000

510

54,000

120,000

8,800

120,000

1,800

1,700

25,000

13,000

13,000

26,000

p. 184

p. 181

p. 178

p. 181

p. 181

p. 178

p. 164

p. 172

p. 172

p. 178

p. 175

p. 162

p. 147

p. 135

p. 150

p. 144

p. 133

p. 102

p. 114

p. 111

p. 130

p. 121

Indeno(1,2,3-

cd)pyrene

SB-19 (1-2') 223 GP-8 (1-2’) 400 U 1,200 510 p. 184 p. 162
Source No: 1

TABLE 4

ESI SOURCE 1 SOIL CONCENTRATIONS

23 Source Characterization

Hazardous 

Substance

Sample 

Identification

(sample depth)

Laboratory 

Sample

Number

Background A Sample

(see Table 2)

Background B Conc.

(see Table 2)

(μg/kg)

Hazardous 

Substance 

Conc.

(μg/kg)

Sample 

Quantitation 

Limit 

(SQL)*(μg/k

g) Ref. 5 Ref. 45

Naphthalene SB-22 (16-18')

SB-23 (3-4')

SB-23 (7-11')

SB-25 (13-14')

SB-5 (4-7')

SB-3 (8-10)

SB-3 (13-16')

SB-2 (13-17')

SB-6 (14-16')

214

219

217

213

202

206

205

212

209

GP-8 (13-14’)

GP-8 (3-4’)

GP-8 (8-10’)

GP-8 (13-14’)

GP-8 (4-7’)

GP-8 (8-10’)

GP-8 (13-14’)

GP-8 (13-14’)

GP-8 (13-14’)

520 U

450 U

450 U

520 U

450 U

450 U

520 U

520 U

520 U

570,000

41,000

600,000

5,100

11,000

170,000

70,000

61,000

130,000

120,000

8,800

120,000

1,800

1,700

25,000

13,000

13,000

26,000

p. 178

p. 181

p. 181

p. 178

p. 164

p. 172

p. 172

p. 178

p. 175

p. 136

p. 150

p. 144

p. 133

p. 102

p. 114

p. 111

p. 130

p. 121

Phenanthrene SB-18 (1-2')

SB-19 (1-2')

SB-22 (3-4')

SB-22 (16-18')

SB-23 (3-4')

SB-23 (7-11')

SB-5 (4-7')

SB-3 (8-10)

SB-3 (13-16')

SB-2 (13-17')

SB-6 (14-16')

221

223

218

214

219

217

202

206

205

212

209

GP-8 (1-2’)

GP-8 (1-2’)

GP-8 (3-4’)

GP-8 (13-14’)

GP-8 (3-4’)

GP-8 (3-4’)

GP-8 (4-7)

GP-8 (8-10’)

GP-8 (13-14’)

GP-8 (13-14’)

GP-8 (13-14’)

400 U

400 U 

450 U

520 U

450 U

450 U

450 U

450 U

520 U

520 U

520 U

8,200

850

170,000

350,000

37,000

500,000

6,800

140,000

80,000

66,000

87,000

1,700

510

54,000

120,000

8,800

120,000

1,700

25,000

13,000

13,000

26,000

p. 184

p. 184

p. 181

p. 178

p. 181

p. 181

p. 164

p. 172

p. 172

p. 178

p. 175

p. 156

p. 162

p. 148

p. 136

p. 150

p. 145

p. 102

p. 114

p. 111

p. 130

p. 121

Pyrene SB-18 (1-2')

SB-19 (1-2')

SB-22 (16-18')

SB-23 (7-11')

SB-5 (4-7')

SB-3 (8-10)

SB-3 (13-16')

SB-2 (13-17')

SB-6 (14-16')

221

223

214

217

202

206

205

212

209

GP-8 (1-2’)

GP-8 (1-2’)

GP-8 (13-14’)

GP-8 (3-4’)

GP-8 (4-7)

GP-8 (8-10’)

GP-8 (13-14’)

GP-8 (13-14’)

GP-8 (13-14’)

400 U

400 U 

520 U

450 U

450 U

450 U

520 U

520 U

520 U

6,000

1,100

140,000

220,000

2,400

57,000

31,000

29,000

31,000

1,700

510

120,000

120,000

1,700

25,000

13,000

13,000

26,000

p. 184

p. 184

p. 178

p. 181

p. 164

p. 172

p. 172

p. 178

p. 175

p. 156

p. 162

p. 136

p. 145

p. 102

p. 114

p. 111

p. 130

p. 121

Notes:

* The SQL is the laboratory's contract required quantitation limit (CRQL), for analyses performed by CLP, or the laboratory's 

reporting limit (RL), for other laboratories, for that analyte with any dilution factor, volume adjustment, or percent solids for that 

sample analysis taken into account (Ref. 45, p. 1). A The background sample used for each source sample is the background sample collected at the same depth as the source sample. 

For source samples collected at the depths of 7 and 11 feet below ground surface, samples GP-8 (4-7’), GP-8 (8-10’), or GP-8 (11-

13’) could be used to establish background levels. As shown in Table 2 of this HRS documentation record, samples SB-1 (11-13’) 

or SB-28 (13-14’) could also be presented as they did not contain PAH compounds. The deepest background samples collected 

were at 13 to 14 feet bgs. Therefore, the background sample collected at 13 to 14 feet bgs was used as background for all soil 

samples collected at depths greater than 13 feet. Note that background contaminant levels are presented to show the relative

increase of facility-related contaminants over background. B The concentration in parenthesis is the detection limit as documented in Table 2 of this HRS documentation record. 

' Feet

μg/L Micrograms per kilogram or parts per billion

Conc. Concentration

U Not detected at or above the reporting limit shown (Ref. 5, p. 129)

Ref. Reference

Also as part of the ESI field work, soil samples were analyzed in the field using the mobile laboratory 

(Ref. 5, p. 13). Soil samples were analyzed for PAH compounds including naphthalene, 

benzo(a)anthracene, benzo(b)fluoranthene / benzo(k)fluoranthene, and benzo(a)pyrene were analyzed 

using the solid phase microextraction (SPME) methodology (Ref. 5, p. 203). 
Source No: 1

24 Source Characterization

Engineering Evaluation/Cost Analysis December 2007 Soil Sampling:

The EE/CA site characterization report for INL&P documents the field activities performed during the 

EE/CA investigation conducted between November 2007 and January 2010. The EE/CA was conducted 

by an environmental consultant for Centel Corporation and Black Hills Corporation in accordance with 

the EPA Administrative Settlement Agreement and Order on Consent Docked No. CERCLA-07-2006-

0159 (Refs. 34, p. 6; 39). The analytical data for soil samples from the EE/CA are used to characterize 

Source 1, area of contaminated soil. 

The EE/CA field activities were completed as specified in the work plan, technical memorandum 1, and 

field sampling plan (Refs. 37; 38; 40). Deviations from the planned work are summarized in Table 2-1,

page 55 of Reference 34. The field investigation included advancing soil borings, collecting soil samples, 

and surveying sampling locations. Sampling included collecting subsurface soil from direct-push probes 

for chemical analysis. These field activities were designed to gather data to better define the approximate

extent of soil contamination at INL&P (Ref. 34, p. 14). 

During historical investigations, extensive soil probing and sampling shallow unsaturated soil was 

completed. However, the investigations did not completely define the approximate vertical extent of soil 

contamination. Therefore, additional investigation of subsurface soils was conducted during the EE/CA. 

In December 2007, 11 soil probes (SP-01 through SP-11) were advanced and subsurface soil samples 

collected for chemical analysis to supplement the existing EPA analytical data suitable for use in a 

baseline risk assessment (Ref. 34, pp. 14, 15). The soil samples delineated the approximate extent of soil 

contamination in the unsaturated zone. The locations of the probes are shown on Figure 2-2, page 76 of 

Reference 34, and soil probe logs are in Appendix C at page 276 of Reference 34 (Ref. 34, pp. 14, 15). 

According to the logs, the soil samples were collected in November and December 2007 (Ref. 34, pp. 276 

to 294). 

Soil probes were advanced with a hydraulic direct-push probing unit. All probes were sampled 

continuously and logged by a geologist to allow for accurate determination of stratigraphy and to screen 

for contamination. Photoionization detector (PID) field screening results are included on the logs (Ref. 

34, pp. 15, 277 - 315).

Soil samples collected from probes SP-01 through SP-09 were submitted for chemical analysis of PAHs 

by SW-846 Method 8270-Selective Ion Monitoring (SIM), VOCs by SW-846 Method 8260B, and arsenic 

by SW-846 Method 6010B. The samples were collected from the zone that was the most visibly 

contaminated or that exhibited the highest PID reading in the 1 to 6 foot, 6 to 12 foot, and 12 to 18 foot 

bgs intervals. The soil samples were collected from the midpoint of the interval if visible contamination 

was not present or the soil exhibited no PID reading in the sample interval. A duplicate sample was 

collected from probe SP-1 from 8.5 to 10.0 feet bgs, and a matrix spike/matrix spike duplicate (MS/MSD) 

sample was collected from probe SP-3 from 8.0 to 8.6 feet bgs. No soil samples were collected from soil 

probes SP-10 and SP-11 for chemical analysis (Ref. 34, pp. 15, 16).

All results received from the analytical laboratory for samples collected during the EE/CA were reviewed,

evaluated, and validated. Data validation reports are included as Appendix O of the EE/CA report (Ref. 

34 pp. 596-650). Data were evaluated using EPA’s Functional Guidelines for Evaluating 

Organics/Inorganics Analyses (EPA 1999, 1994) (Ref. 34, p. 27). Reference 38 provides the work plan 

followed for sample validation. 

Visible contamination, odors, or PID readings identified during probing or well installation were recorded 

on the logs presented in Appendix D of Reference 34. Figure 2-2 on page 76 of Reference 34 shows the 

soil probe locations. Table 4-1 page 58 of Reference 34 summarizes the field observations recorded (such 
Source No: 1

25 Source Characterization

as visible tar, tar odors, and VOCs detected by the PID) during soil probing. A summary of Table 4-1 is 

provided in Table 5 of this HRS documentation record. Indications of contamination were present in all 

soil probes except in probe P-10, which was advanced along 5th Street, approximately two blocks east of 

INL&P (Ref. 34, pp. 28, 58).

TABLE 5

OBSERVATONS OF CONTAMINATION IN SOIL PROBES

ENGINEERING EVALUTION/COST EVALUTION

Sample 

Identification Odors

PID Reading Greater 

than 

1 ppm Observations Reference

SP-01 Tar odor entire 

depth.

Range from 11.9 to 

1,724 ppm from 0.5 to 

19 feet bgs. Peak 

reading at 16 feet bgs.

Tar coating on sampling sleeve/sample 

tar coated from 10 to 16 feet bgs. Tar 

saturated from 15.2 to 15.8 feet bgs. 

Sand tar coated from 18.7 to 20 feet 

bgs.

34, pp. 58, 

277

SP-02 Faint tar odor 

from 0.5 to 5 feet 

bgs. Tar odor 

from 5 to 12 feet 

bgs.

Range from 8.8 to 634 

ppm from 0.5 to 17 feet 

bgs. Peak reading at 13 

feet bgs.

Tar coated from 13.6 to 16 feet bgs. 34, pp. 58, 

278

SP-03 Strong tar odor 

from 10 to 20 feet 

bgs.

Range from 8.7 to 649 

ppm from 4 to 17 feet 

bgs. Peak reading at 

127 feet bgs.

Tar coated from 16.6 to 20 feet bgs. 34, pp. 58, 

279

SP-04 Tar odor from 5 to 

10 feet bgs.

Range from 12.1 to 295 

ppm from 0.5 to 19 feet 

bgs. Peak reading at 19 

feet bgs.

Tar coated from 12.6 to 12.9 feet bgs. 

Sampling sleeve had a tar smear from 

18 to 20 feet bgs.

34, pp. 58, 

280

SP-05 Strong tar odor

from 5 to 21 feet 

bgs. Petroleum 

odor from 35 to 

46 feet bgs.

Range from 5.9 to 

1,503 ppm from 0.5 to 

54 feet bgs. Peak 

reading at 18 feet bgs.

Visible tar from 7 to 10 feet bgs. Tar 

coated from 10 to 17.7 feet bgs in 

clay. Tar coated from 20 to 21 feet 

bgs in sand. Tar staining begins 

grading out at 27 feet bgs. Tar stained 

from 35 to 35.5 feet bgs.

34, pp. 58, 

281, 282

SP-06 Petroleum odor at 

8 feet bgs.

Range from 1.1 to 175 

ppm from 9 to 31 feet 

bgs. Peak reading at 18 

feet bgs.

Petroleum saturated 24.7 feet bgs. 

Petroleum coated seam from 27 to 

27.1 feet bgs and 27.7 to 27.8 feet bgs.

34, pp. 58, 

283, 284

SP-07 None recorded. Range from 40.2 to 271 

ppm from 0.5 to 5 feet 

bgs. Peak reading at 5 

feet bgs.

Tar saturated from 5 to 7 feet bgs. 34, pp. 58, 

286
Source No: 1

26 Source Characterization

TABLE 5 (Continued)

OBSERVATONS OF CONTAMINATION IN SOIL PROBES

ENGINEERING EVALUTION/COST EVALUTION

Sample 

Identification Odors

PID Reading 

greater than 

1 ppm Observations Reference

SP-08 Tar odor from 18 to 

19.2 feet bgs. 

Strong tar odor at 

25.6 feet bgs. Faint 

gas odor above 

glacial till.

Range from 1.1 to 

92.6 ppm from 7 to 

32 feet bgs. Peak 

reading at 25 feet 

bgs.

Tar stained at 25.6 feet bgs and from 27 

to 27.8 feet bgs.

34, pp. 58, 

287, 288

SP-09 None. None. None. Probe refusal at 7 feet bgs. 34, pp. 58, 

289

SP-10 None. PID measurements 

less than 1 ppm 

throughout probe.

No contamination evident 34, pp. 58, 

290, 291, 

292

SP-11 Petroleum odor at 

16.7 to 17.9 feet 

bgs, petroleum odor 

from 20.3 to 21.3 

feet bgs.

Range from 1.0 to 

19 ppm from 18 to 

21 feet bgs. Peak 

reading at 18 feet 

bgs.

Black staining from 16.7 to 17.9 and 

20.3 to 21.3 feet bgs.

34, pp. 58, 

293

Notes:

bgs Below ground surface

PID Photoionization detector

ppm Parts per million

Engineering Evaluation/Cost Analysis - Background and Release Concentrations: 

The background concentrations for soil samples from 2000 were used to supplement background 

concentrations for the soil samples collected in 2007 during the EE/CA soil investigation. These 

locations collected during the ESI documented an absence of contamination at locations away from the 

source. Documentation on the background soil samples from the ESI is provided in Tables 1 and 2 of this 

HRS documentation record. Additionally, Table 5-2, page 66 of Reference 34 provides background 

concentrations for PAHs from various publications. No off-property soil samples were collected as part 

of the EE/CA, rather all samples were located on the facility (Ref. 34, p. 76). However, one location (SP08) sampled during the EE/CA was located outside the historic structure footprint at the former MGP 

(Ref. 34, p. 76). This sample contained significantly lower concentrations of PAH compounds when 

compared to samples collected near or within areas where historic structures were located (Ref. 34, pp. 

59, 76). The results for two samples collected from SP-08 are presented in Table 7 below.
Source No: 1

27 Source Characterization

TABLE 6

EE/CA BACKGROUND SOIL SAMPLES

Sample Identification

(feet below ground surface)

Laboratory Sample 

Number

Sample 

Medium Date Reference

SP-8 (5-6) 6032085007 Soil 11/30/2007 34, p. 287, 621

SP-8 (7-8) 6032085008 Soil 11/30/2007 34, p. 287, 621

TABLE 7

EE/CA BACKGROUND SOIL CONCENTRATIONS

Hazardous Substance

Sample 

Identification

(sample depth)

Laboratory

Sample

Number

Hazardous 

Substance 

Concentration 

(mg/kg)

Method 

Detection 

Limit (MDL)

(mg/kg) Reference 34

Acenaphthene SP-8 (5-6)

SP-8 (7-8)

6032085007

6032085008

ND

ND

0.0013

0.00024

p. 449

Acenaphthylene SP-8 (5-6)

SP-8 (7-8)

6032085007

6032085008

0.0641

ND

0.0026

0.00048

p. 449

Anthracene SP-8 (5-6)

SP-8 (7-8)

6032085007

6032085008

0.0723

0.0020

0.0032

0.00061

p. 449

Benzo(a)anthracene SP-8 (5-6)

SP-8 (7-8)

6032085007

6032085008

0.232

ND

0.0026

0.00048

p. 449

Benzo(a)pyrene SP-8 (5-6)

SP-8 (7-8)

6032085007

6032085008

0.134

ND

0.0038

0.00073

p. 449

Benzo(b)fluoranthene SP-8 (5-6)

SP-8 (7-8)

6032085007

6032085008

0.422

ND

0.0045

0.00085

p. 449

Benzo(g,h,i)perylene SP-8 (5-6)

SP-8 (7-8)

6032085007

6032085008

0.113

ND

0.0026

0.00048

p. 449

Chrysene SP-8 (5-6)

SP-8 (7-8)

6032085007

6032085008

0.202

ND

0.0019

0.00036

pp. 449, 450

Fluoranthene SP-8 (5-6)

SP-8 (7-8)

6032085007

6032085008

0.321

ND

0.0045

0.00085

pp. 449, 450

Fluorene SP-8 (5-6)

SP-8 (7-8)

6032085007

6032085008

ND

ND

0.0019

0.00036

pp. 449, 450

Indeno(1,2,3-cd)pyrene SP-8 (5-6)

SP-8 (7-8)

6032085007

6032085008

0.112

ND

0.0038

0.00073

pp. 449, 450

Naphthalene SP-8 (5-6)

SP-8 (7-8)

6032085007

6032085008

0.214

ND

0.0019

0.00036

pp. 449, 450

Phenanthrene SP-8 (5-6)

SP-8 (7-8)

6032085007

6032085008

0.548

0.0100

0.0038

0.00073

pp. 449, 450

Pyrene SP-8 (5-6)

SP-8 (7-8)

6032085007

6032085008

0.35

ND

0.0032

0.00061

pp. 449, 450

Notes:

* The SQL is the laboratory's method detection limit (MDL) (Ref. 34, pp. 449, 450).

" Inches

' Feet

μg/kg Micrograms per kilogram or parts per billion

GP Geoprobe

Twenty-two subsurface soil samples were collected from the nine soil probes advanced on facility during 

the EE/CA field investigation. The sampling locations are shown in Reference 34, page 75. The 

complete analytical data are presented in Appendix J of Reference 34. Soil samples collected from 
Source No: 1

28 Source Characterization

INL&P with hazardous substances that are used in delineating the approximate extent of source 1 are 

summarized in Table 8, and the locations are shown on Figure 2 of this HRS documentation record (Ref. 

1, Section 2.3). The concentrations of hazardous substances detected in the source samples are 

summarized in Table 9 of this HRS documentation record. Visible contamination (waste) was observed 

in the soil samples (see Table 5 in this HRS documentation record). The soil samples were collected from 

biased locations, where former MGP structures were located and known to have contained hazardous 

substances (Ref. 34, Figure 2-2, p. 76). The hazardous substances detected in the source samples such as 

PAHs are not naturally occurring but are created from a variety of anthropogenic activities (Ref. 42). 

TABLE 8

ENGINEERING EVALUTION/COST ANALYSIS

SUMMARY OF SOURCE 1 SAMPLES - 2007

Sample Identification

(feet below ground surface)*

Laboratory Sample 

Number Sample Medium Date Reference

SP-1 (4-5)

SP01S0104-05P

6032561010 Soil 12/06/2007 34, p. 277, 637

SP-1 (8.5-10)

SP01S0208.5-10P

6032561011 Soil 12/06/2007 34, p. 277, 637

SP-1 (15-16)

SP01S0315-15P

6032561012 Soil 12/06/2007 34, p. 277, 637

SP-2 (4-5)

SP02S0104-05P

6032561014 Soil 12/06/2007 34, p. 278, 637

SP-2 (9-10)

SP02S0209-10P

6032561015 Soil 12/06/2007 34, p. 278, 637

SP-3 (4.5-5.5)

SP03S0104.5-05.5P

6032561017 Soil 12/06/2007 34, p. 279, 637

SP-3 (8-8.6)

SP03S0208-08.6P

6032561018 Soil 12/06/2007 34, p. 279, 638

SP-3 (12-13)

SP03S0312-13P

6032561019 Soil 12/06/2007 34, p. 279, 638

SP-4 (12.5-13.4)

SP04S0112.5-13.4P

6032561005 Soil 12/05/2007 34, p. 280, 637

SP-5 (2.5-3.5)

SP05S0102.5-03.5P

6032561007 Soil 12/06/2007 34, p. 281, 637

SP-5 (8-9)

SP05S0208-09P

6032561008 Soil 12/06/2007 34, p. 281, 637

SP-5 (11-12)

SP05S0311-12P

6032561009 Soil 12/06/2007 34, p. 281, 637

SP-6 (3-4)

SP06S0103-04P

6032085004 Soil 11/28/2007 34, p. 283, 621

SP-6 (9-10)

SP06S0109-10P

6032085005 Soil 11/28/2007 34, p. 283, 621

SP-7 (5-6)

SP07S0105-06P

6032561006 Soil 12/06/2007 34, p. 286, 637
Source No: 1

29 Source Characterization

Sample Identification

(feet below ground surface)*

Laboratory Sample 

Number Sample Medium Date Reference

SP-9 (3-4)

SP09SO103-04P

6032085009 Soil 11/30/2007 34, p. 289, 622

Notes:

* The SP-X designation is used for displaying the sample on figures and in tables. The longer sample designation is how 

the sample is named on boring logs and in the data validation reports.

SP Soil probe
Source No: 1

30 Source Characterization

TABLE 9

ENGINEERING EVALUTION/COST ANALYSIS

2007 SOURCE 1 SOIL CONCENTRATIONS 

Hazardous 

Substance

Sample

Identification

(ft bgs)A

Background 

Sample

(ft bgs)

B

Background 

Concentration 

(MDL mg/kg)

C

Hazardous 

Substance 

Concentration 

(mg/kg)

Method 

Detection 

Limit (MDL) 

(mg/kg)

Reference

34

Acenaphthene SP-1 (4-5)

SP-1 (8.5-10)

SP-1 (15-16)

SP-2 (9-10)

SP-2 (12-12.5)

SP-3 (8-8.6)

SP-3 (12-13)

SP-4 (2-2.5)

SP-4 (7-8)

SP-4 (12.5-13.4)

SP-5 (2.5-3.5)

SP-5 (8-9)

SP-5 (11-12)

SP-6 (9-10)

SP-7 (5-6)

SP-9 (3-4)

GP-8 (4-7)

GP-8 (8-10)

GP-8 (13-14)

GP-8 (8-10)

GP-8 (11-13)

GP-8 (8-10)

GP-8 (11-13)

GP-8 (3-4)

SP-08 (7-8)

GP-8 (11-13)

GP-8 (3-4)

GP-8 (8-10)

GP-8 (11-13)

GP-8 (8-10)

SP-08 (5-6)

GP-8 (3-4)

ND (0.450)

ND (0.450)

ND (0.520)

ND (0.450)

ND (0.470)

ND (0.450)

ND (0.470)

ND (0.450)

ND (0.00024)

ND (0.470)

ND (0.450)

ND (0.450)

ND (0.470)

ND (0.450)

ND (0.0013)

ND (0.450)

13

40.4

92.4

2.06

1.9

1.93

0.577

13.8

31.8

17.4

32.3

143

18.7

18.3

628

0.542

0.0246

0.0241

0.126

0.0024

0.0024

0.0024

0.0026

0.122

0.119

0.0266

0.025

0.121

0.125

0.0121

2.99

0.0011

p. 441

p. 441

p. 442

p. 443

p. 443

p. 444

p. 445

p. 445

p. 445

p. 446

p. 446

p. 447

p. 447

p. 448

p. 448

p. 450

Acenaphthylene SP-1 (4-5)

SP-1 (8.5-10)

SP-1 (15-16)

SP-3 (4.5-5.5)

SP-4 (2-2.5)

SP-4 (7-8)

SP-4 (12.5-13.4)

SP-5 (2.5-3.5)

SP-5 (8-9)

SP-5 (11-12)

SP-6 (9-10)

SP-7 (5-6)

GP-8 (4-7)

GP-8 (8-10)

GP-8 (13-14)

GP-8 (4-7)

GP-8 (3-4)

SP-08 (7-8)

GP-8 (11-13)

GP-8 (3-4)

GP-8 (8-10)

GP-8 (11-13)

GP-8 (8-10)

SP-08 (5-6)

ND (0.450)

ND (0.450)

ND (0.520)

ND (0.450)

ND (0.450)

ND (0.00048)

ND (0.470)

ND (0.450)

ND (0.450)

ND (0.470)

ND (0.450)

0.0641 (0.0026)

6.34

8.46

19.7

1.1

2.94

15.2

3.59

5.31

21

2.61

2.62

215

0.0492

0.0482

0.253

0.0049

0.244

0.237

0.0532

0.0501

0.241

0.25

0.0243

5.98

p. 441

p. 442

p. 442

p. 444

p. 445

p. 445

p. 446

p. 446

p. 447

p. 447

p. 448

p. 449
Source No: 1

31 Source Characterization

TABLE 9 (Continued)

ENGINEERING EVALUTION/COST ANALYSIS

2007 SOURCE 1 SOIL CONCENTRATIONS

Hazardous 

Substance

Sample 

Identification

(ft bgs)

A

Background 

Sample

(ft bgs)

B

Background 

Concentration 

(MDL mg/kg)

C

Hazardous 

Substance 

Concentration 

(mg/kg)

Method 

Detection 

Limit (MDL) 

(mg/kg)

Reference

34

Anthracene SP-1 (4-5)

SP-1 (8.5-10)

SP-1 (15-16)

SP-2 (9-10)

SP-2 (12-12.5)

SP-3 (8-8.6)

SP-4 (2-2.5)

SP-4 (7-8)

SP-4 (12.5-13.4)

SP-5 (2.5-3.5)

SP-5 (8-9)

SP-5 (11-12)

SP-6 (9-10)

SP-7 (5-6)

SP-9 (3-4)

GP-8 (4-7)

GP-8 (8-10)

GP-8 (13-14)

GP-8 (8-10)

GP-8 (11-13)

GP-8 (8-10)

GP-8 (3-4)

SP-08 (7-8)

GP-8 (11-13)

GP-8 (3-4)

GP-8 (8-10)

GP-8 (11-13)

GP-8 (8-10)

SP-08 (5-6)

GP-8 (3-4)

ND (0.450)

ND (0.450)

ND (0.520)

ND (0.450)

ND (0.470)

ND (0.450)

ND (0.450)

0.0020 (0.00061)

ND (0.470)

ND (0.450)

ND (0.450)

ND (0.470)

ND (0.450)

0.0723 (0.0032)

ND (0.450)

7.41

45.5

38.7

0.82

0.72

0.801

14.6

77.2

6.79

11.8

49.3

8.69

10.9

332

0.73

0.0615

0.612

0.316

0.006

0.0061

0.0061

0.305

0.297

0.0665

0.0626

0.301

0.312

0.0303

7.48

0.0028

p. 441

p. 441

p. 442

p. 443

p. 443

p. 444

p. 445

p. 445

p. 446

p. 446

p. 447

p. 447

p. 448

p. 449

p. 450

Benzo(a)

anthracene

SP-1 (4-5)

SP-1 (8.5-10)

SP-1 (15-16)

SP-2 (9-10)

SP-3 (4.5-5.5)

SP-3 (8-8.6)

SP-4 (2-2.5)

SP-4 (7-8)

SP-4 (12.5-13.4)

SP-5 (2.5-3.5)

SP-5 (8-9)

SP-5 (11-12)

SP-6 (9-10)

SP-7 (5-6)

SP-9 (3-4)

GP-8 (4-7)

GP-8 (8-10)

GP-8 (13-14)

GP-8 (8-10)

GP-8 (4-7)

GP-8 (8-10)

GP-8 (3-4)

SP-08 (7-8)

GP-8 (11-13)

GP-8 (3-4)

GP-8 (8-10)

GP-8 (11-13)

GP-8 (8-10)

SP-08 (5-6)

GP-8 (3-4)

ND (0.450)

ND (0.450)

ND (0.520)

ND (0.450)

ND (0.450)

ND (0.450)

ND (0.450)

ND (0.00048)

ND (0.470)

ND (0.450)

ND (0.450)

ND (0.470)

ND (0.450)

0.232 (0.0026)

ND (0.450)

4.87

12.7

18.7

0.62

0.728

0.601

4.62

43.5

5

6.39

29.5

2.6

8.2

206

1.72

0.0492

0.0482

0.253

0.0048

0.0049

0.0049

0.244

0.237

0.0532

0.0501

0.241

0.25

0.0243

5.98

0.0022

p. 441

p. 442

p. 442

p. 443

p. 444

p. 444

p. 445

p. 445

p. 446

p. 446

p. 447

p. 447

p. 448

p. 449

p. 450
Source No: 1

32 Source Characterization

TABLE 9 (Continued)

ENGINEERING EVALUTION/COST ANALYSIS

2007 SOURCE 1 SOIL CONCENTRATIONS

Hazardous 

Substance

Sample 

Identification

(ft bgs)

A

Background 

Sample

(ft bgs)

B

Background 

Concentration

(MLD mg/kg)

C

Hazardous 

Substance 

Concentration 

(mg/kg)

Method 

Detection 

Limit (MDL) 

(mg/kg)

Reference

34

Benzo(a)

pyrene

SP-1 (4-5)

SP-1 (8.5-10)

SP-1 (15-16)

SP-3 (4.5-5.5)

SP-4 (2-2.5)

SP-4 (7-8)

SP-4 (12.5-13.4)

SP-5 (2.5-3.5)

SP-5 (8-9)

SP-5 (11-12)

SP-6 (9-10)

SP-7 (5-6)

SP-9 (3-4)

GP-8 (4-7)

GP-8 (8-10)

GP-8 (13-14)

GP-8 (4-7)

GP-8 (3-4)

SP-08 (7-8)

GP-8 (11-13)

GP-8 (3-4)

GP-8 (8-10)

GP-8 (11-13)

GP-8 (8-10)

SP-08 (5-6)

GP-8 (3-4)

ND (0.450)

ND (0.450)

ND (0.520)

ND (0.450)

ND (0.450)

ND (0.00073)

ND (0.470)

ND (0.450)

ND (0.450)

ND (0.470)

ND (0.450)

0.134 (0.0038)

ND (0.450)

2.21

5.33

9.39

0.918

2.6

26.6

2.93

3.42

15.7

2.55

6.18

114

1

0.0738

0.0724

0.379

0.0073

0.366

0.356

0.0798

0.0751

0.362

0.375

0.0364

8.89

0.0033

p. 441

p. 442

p. 442

p. 444

p. 445

p. 446

p. 446

p. 446

p. 447

p. 447

p. 448

p. 449

p. 450

Benzo(b)

fluoranthene

SP-1 (4-5)

SP-1 (8.5-10)

SP-1 (15-16)

SP-3 (4.5-5.5)

SP-4 (2-2.5)

SP-4 (7-8)

SP-4 (12.5-13.4)

SP-5 (2.5-3.5)

SP-5 (8-9)

SP-5 (11-12)

SP-6 (9-10)

SP-7 (5-6)

SP-9 (3-4)

GP-8 (4-7)

GP-8 (8-10)

GP-8 (13-14)

GP-8 (4-7)

GP-8 (3-4)

SP-08 (7-8)

GP-8 (11-13)

GP-8 (3-4)

GP-8 (8-10)

GP-8 (11-13)

GP-8 (8-10)

SP-08 (5-6)

GP-8 (3-4)

ND (0.450)

ND (0.450)

ND (0.520)

ND (0.450)

ND (0.450)

ND (0.00085)

ND (0.470)

ND (0.450)

ND (0.450)

ND (0.470)

ND (0.450)

0.422 (0.0045)

ND (0.450)

2.86

7.16

12.2

1.72

4.51

38.2

4.2

5.11

21.7

2.75

9.47

174

2.25

0.0862

0.0844

0.443

0.0085

0.427

0.416

0.0931

0.0876

0.422

0.437

0.0425

10.5

0.0039

p. 441

p. 442

p. 442

p. 444

p. 445

p. 446

p. 446

p. 446

p. 447

p. 447

p. 448

p. 449

p. 450
Source No: 1

33 Source Characterization

TABLE 9 (Continued)

ENGINEERING EVALUTION/COST ANALYSIS

2007 SOURCE 1 SOIL CONCENTRATIONS

Hazardous 

Substance

Sample 

Identification

(ft bgs)

A

Background

Sample

(ft bgs)

B

Background 

Concentration 

(MDL mg/kg)

C

Hazardous 

Substance 

Concentration 

(mg/kg)

Method 

Detection 

Limit (MDL) 

(mg/kg)

Reference

34

Benzo(g,h,i)

perylene

SP-1 (4-5)

SP-1 (8.5-10)

SP-1 (15-16)

SP-3 (4.5-5.5)

SP-4 (2-2.5)

SP-4 (7-8)

SP-4 (12.5-13.4)

SP-5 (2.5-3.5)

SP-5 (8-9)

SP-5 (11-12)

SP-6 (3-4)

SP-6 (9-10)

SP-7 (5-6)

GP-8 (4-7)

GP-8 (8-10)

GP-8 (13-14)

GP-8 (4-7)

GP-8 (3-4)

SP-08 (7-8)

GP-8 (11-13)

GP-8 (3-4)

GP-8 (8-10)

GP-8 (11-13)

GP-8 (3-4)

GP-8 (8-10)

SP-08 (5-6)

ND (0.450)

ND (0.450)

ND (0.520)

ND (0.450)

ND (0.450)

ND (0.00048)

ND (0.470)

ND (0.450)

ND (0.450)

ND (0.470)

ND (0.450)

ND (0.450)

0.113 (0.0026)

1.22

1.87

4.68

0.708

2.14

12.1

1.32

1.51

6.17

0.946

0.0025

3.24

79.2

0.0492

0.0482

0.253

0.0049

0.244

0.237

0.0532

0.0501

0.241

0.25

0.021

0.0243

5.98

p. 441

p. 442

p. 442

p. 444

p. 445

p. 446

p. 446

p. 446

p. 447

p. 447

p. 448

p. 448

p. 449

Chrysene SP-1 (4-5)

SP-1 (8.5-10)

SP-1 (15-16)

SP-3 (4.5-5.5)

SP-4 (2-2.5)

SP-4 (7-8)

SP-4 (12.5-13.4)

SP-5 (2.5-3.5)

SP-5 (8-9)

SP-5 (11-12)

SP-6 (9-10)

SP-7 (5-6)

SP-9 (3-4)

GP-8 (4-7)

GP-8 (8-10)

GP-8 (13-14)

GP-8 (4-7)

GP-8 (3-4)

SP-08 (7-8)

GP-8 (11-13)

GP-8 (3-4)

GP-8 (8-10)

GP-8 (11-13)

GP-8 (8-10)

SP-08 (5-6)

GP-8 (3-4)

ND (0.450)

ND (0.450)

ND (0.520)

ND (0.450)

ND (0.450)

ND (0.00036)

ND (0.470)

ND (0.450)

ND (0.450)

ND (0.470)

ND (0.450)

0.202 (0.0019)

ND (0.450)

3.82

9.70

16.3

0.914

3.94

31.8

3.96

5.1

22.9

2.83

6.68

160

1.29

0.0369

0.0362

0.19

0.0036

0.183

0.178

0.0399

0.0376

0.181

0.187

0.0182

4.49

0.0017

p. 441

p. 442

p. 442

p. 444

p. 445

p. 446

p. 446

p. 446

p. 447

p. 447

p. 448

p. 449

p. 450
Source No: 1

34 Source Characterization

TABLE 9 (Continued)

ENGINEERING EVALUTION/COST ANALYSIS

2007 SOURCE 1 SOIL CONCENTRATIONS

Hazardous 

Substance

Sample 

Identification

(ft bgs)

A

Background 

Sample

(ft bgs)

B

Background 

Concentration

(MDL mg/kg)

C

Hazardous 

Substance 

Concentration 

(mg/kg)

Method 

Detection 

Limit (MDL) 

(mg/kg) Reference 34

Fluoranthene SP-1 (4-5)

SP-1 (8.5-10)

SP-1 (15-16)

SP-2 (4-5)

SP-2 (12-12.5)

SP-3 (4.5-5.5)

SP-3 (8-8.6)

SP-3 (12-13)

SP-4 (7-8)

SP-4 (12.5-13.4)

SP-5 (2.5-3.5)

SP-5 (8-9)

SP-5 (11-12)

SP-6 (9-10)

SP-7 (5-6)

GP-8 (4-7)

GP-8 (8-10)

GP-8 (13-14)

GP-8 (4-7)

GP-8 (11-13)

GP-8 (4-7)

GP-8 (8-10)

GP-8 (11-13)

SP-08 (7-8)

GP-8 (11-13)

GP-8 (3-4)

GP-8 (8-10)

GP-8 (11-13)

GP-8 (3-4)

SP-08 (5-6)

ND (0.450)

ND (0.450)

ND (0.520)

ND (0.450)

ND (0.470)

ND (0.450)

ND (0.450)

ND (0.470)

ND (0.00085)

ND (0.470)

ND (0.450)

ND (0.450)

ND (0.470)

ND (0.450)

0.321 (0.0045)

7.25

17.4

31.5

0.0234

0.477

0.667

0.997

0.335

87

8.44

10.7

46.8

5.36

16.5

298

0.0862

0.0844

0.443

0.00069

0.0086

0.0085

0.0085

0.0092

0.416

0.0931

0.0876

0.422

0.437

0.0425

10.5

p. 441

p. 442

p. 442

p. 443

p. 443

p. 444

p. 444

p. 445

p. 446

p. 446

p. 447

p. 447

p. 447

p. 448

p. 449

Fluorene SP-1 (4-5)

SP-1 (8.5-10)

SP-1 (15-16)

SP-2 (9-10)

SP-2 (12-12.5)

SP-3 (8-8.6)

SP-4 (2-2.5)

SP-4 (7-8)

SP-4 (12.5-13.4)

SP-5 (2.5-3.5)

SP-5 (8-9)

SP-5 (11-12)

SP-6 (9-10)

SP-7 (5-6)

GP-8 (4-7)

GP-8 (8-10)

GP-8 (13-14)

GP-8 (8-10)

GP-8 (11-13)

GP-8 (8-10)

GP-8 (3-4)

SP-08 (7-8)

GP-8 (11-13)

GP-8 (3-4)

GP-8 (8-10)

GP-8 (11-13)

GP-8 (8-10)

SP-08 (5-6)

ND (0.450)

ND (0.450)

ND (0.520)

ND (0.450)

ND (0.470)

ND (0.450)

ND (0.450)

ND (0.00036)

ND (0.470)

ND (0.450)

ND (0.450)

ND (0.470)

ND (0.450)

ND (0.0019)

12.1

30.6

55.9

1.45

1.05

1.52

12.7

69.9

9.90

16.3

70

11.1

13.2

484

0.0369

0.0362

0.19

0.0036

0.0037

0.0037

0.183

0.178

0.0399

0.0376

0.181

0.187

0.0182

4.49

p. 441

p. 442

p. 442

p. 443

p. 443

p. 444

p. 445

p. 446

p. 446

p. 447

p. 447

p. 447

p. 448

p. 449
Source No: 1

35 Source Characterization

TABLE 9 (Continued)

ENGINEERING EVALUTION/COST ANALYSIS

2007 SOURCE 1 SOIL CONCENTRATIONS

Hazardous 

Substance

Sample 

Identification

(ft bgs)

A

Background 

Sample

(ft bgs)

B

Background 

Concentration 

(MDL mg/kg)

C

Hazardous 

Substance 

Concentration 

(mg/kg)

Method 

Detection Limit 

(MDL) (mg/kg) Reference 34

Indeno(1,2,3

-cd)pyrene

SP-1 (4-5)

SP-1 (8.5-10)

SP-1 (15-16)

SP-3 (4.5-5.5)

SP-4 (2-2.5)

SP-4 (7-8)

SP-4 (12.5-13.4)

SP-5 (2.5-3.5)

SP-5 (8-9)

SP-6 (9-10)

SP-7 (5-6)

GP-8 (4-7)

GP-8 (8-10)

GP-8 (13-14)

GP-8 (4-7)

GP-8 (3-4)

SP-08 (7-8)

GP-8 (11-13)

GP-8 (3-4)

GP-8 (8-10)

GP-8 (8-10)

SP-08 (5-6)

ND (0.450)

ND (0.450)

ND (0.520)

ND (0.450)

ND (0.450)

ND (0.00073)

ND (0.470)

ND (0.450)

ND (0.450)

ND (0.450)

0.112 (0.0038)

0.795

1.82

3.26

0.603

1.36

10.6

1.1

1.29

6.11

2.8

47.8

0.0738

0.0724

0.379

0.0073

0.366

0.356

0.0798

0.0751

0.362

0.0364

8.98

p. 441

p. 442

p. 442

p. 444

p. 445

p. 446

p. 446

p. 447

p. 447

p. 448

p. 449

Naphthalene SP-1 (4-5)

SP-1 (8.5-10)

SP-1 (15-16)

SP-2 (9-10)

SP-2 (12-12.5)

SP-3 (4.5-5.5)

SP-3 (8-8.6)

SP-3 (12-13)

SP-4 (2-2.5)

SP-4 (7-8)

SP-4 (12.5-13.4)

SP-5 (2.5-3.5)

SP-5 (8-9)

SP-5 (11-12)

SP-6 (9-10)

SP-7 (5-6)

SP-9 (3-4)

GP-8 (4-7)

GP-8 (8-10)

GP-8 (13-14)

GP-8 (8-10)

GP-8 (11-13)

GP-8 (4-7)

GP-8 (8-10)

GP-8 (11-13)

GP-8 (3-4)

SP-08 (7-8)

GP-8 (11-13)

GP-8 (3-4)

GP-8 (8-10)

GP-8 (11-13)

GP-8 (8-10)

SP-08 (5-6)

GP-8 (3-4)

ND (0.450)

ND (0.450)

ND (0.520)

ND (0.450)

ND (0.470)

ND (0.450)

ND (0.450)

ND (0.470)

ND (0.450)

ND (0.00036)

ND (0.470)

ND (0.450)

ND (0.450)

ND (0.470)

ND (0.450)

0.214 (0.0019)

ND (0.450)

24.6

77.1

373

6.87

9.02

0.932

7.28

3.42

45.7

493

55.2

89.9

385

79.4

11.8

1,950

2.63

0.0369

0.0362

0.19

0.0036

0.0037

0.0036

0.0037

0.0039

0.183

0.178

0.0399

0.0376

0.181

0.187

0.0182

4.49

0.0017

p. 441

p. 442

p. 442

p. 443

p. 444

p. 444

p. 444

p. 445

p. 445

p. 446

p. 446

p. 447

p. 447

p. 447

p. 448

p. 449

p. 450
Source No: 1

36 Source Characterization

TABLE 9 (Continued)

ENGINEERING EVALUTION/COST ANALYSIS

2007 SOURCE 1 SOIL CONCENTRATIONS

Hazardous 

Substance

Sample 

Identification

(ft bgs)

A

Background 

Sample

(ft bgs)B

Background 

Concentration 

(MDL mg/kg)

C

Hazardous 

Substance 

Concentration 

(mg/kg)

Method 

Detection Limit 

(MDL)

(mg/kg)

Reference 

34

Phenanthrene SP-1 (4-5)

SP-1 (8.5-10)

SP-1 (15-16)

SP-2 (9-10)

SP-2 (12-12.5)

SP-3 (4.5-5.5)

SP-3 (8-8.6)

SP-3 (12-13)

SP-4 (2-2.5)

SP-4 (7-8)

SP-4 (12.5-13.4)

SP-5 (2.5-3.5)

SP-5 (8-9)

SP-5 (11-12)

SP-6 (9-10)

SP-7 (5-6)

SP-9 (3-4)

GP-8 (4-7)

GP-8 (8-10)

GP-8 (13-14)

GP-8 (8-10)

GP-8 (11-13)

GP-8 (4-7)

GP-8 (8-10)

GP-8 (11-13)

GP-8 (3-4)

SP-08 (7-8)

GP-8 (11-13)

GP-8 (3-4)

GP-8 (8-10)

GP-8 (11-13)

GP-8 (8-10)

SP-08 (5-6)

GP-8 (3-4)

ND (0.450)

ND (0.450)

ND (0.520)

ND (0.450)

ND (0.470)

ND (0.450)

ND (0.450)

ND (0.470)

ND (0.450)

0.0100 (0.00073)

ND (0.470)

ND (0.450)

ND (0.450)

ND (0.470)

ND (0.450)

0.548 (0.0038)

ND (0.450)

31.4

81.7

177

3.88

3.12

0.767

3.71

1.47

43.5

331

34.9

53.5

221

24.9

42.7

1,230

4.09

0.0738

0.0724

0.379

0.0072

0.0073

0.0073

0.0073

0.0079

0.366

0.356

0.0798

0.0751

0.362

0.375

0.0364

8.98

0.0033

p. 441

p. 442

p. 442

p. 443

p. 444

p. 444

p. 444

p. 445

p. 445

p. 446

p. 446

p. 447

p. 447

p. 447

p. 448

p. 449

p. 450

Pyrene SP-1 (4-5)

SP-1 (8.5-10)

SP-1 (15-16)

SP-2 (9-10)

SP-2 (12-12.5)

SP-3 (4.5-5.5)

SP-3 (8-8.6)

SP-4 (2-2.5)

SP-4 (7-8)

SP-4 (12.5-13.4)

SP-5 (2.5-3.5)

SP-5 (8-9)

SP-5 (11-12)

SP-6 (9-10)

SP-7 (5-6)

SP-9 (3-4)

GP-8 (4-7)

GP-8 (8-10)

GP-8 (13-14)

GP-8 (8-10)

GP-8 (11-13)

GP-8 (4-7)

GP-8 (8-10)

GP-8 (3-4)

SP-08 (7-8)

GP-8 (11-13)

GP-8 (3-4)

GP-8 (8-10)

GP-8 (11-13)

GP-8 (8-10)

SP-08 (5-6)

GP-8 (3-4)

ND (0.450)

ND (0.450)

ND (0.520)

ND (0.450)

ND (0.470)

ND (0.450)

ND (0.450)

ND (0.450)

ND (0.00061)

ND (0.470)

ND (0.450)

ND (0.450)

ND (0.470)

ND (0.450)

0.35 (0.0032)

ND (0.450)

10.7

34

44.3

1.55

0.775

1.94

1.4

15.7

105

10.8

15.1

67.3

8.34

20.4

449

2.37

0.0615

0.0603

0.316

0.006

0.0061

0.0061

0.0061

0.305

0.297

0.0665

0.0626

0.301

0.312

0.0303

7.48

0.0028

p. 441

p. 442

p. 442

p. 443

p. 444

p. 444

p. 444

p. 445

p. 446

p. 446

p. 447

p. 447

p. 447

p. 448

p. 449

p. 450

Notes:

A The sample identifications are different on the figures, in the text of the report, and on the sample data sheets. The 

figures and text provide only the soil probe sample location, such as SB-1 (Ref. 34, pp. 58, 76). The soil probe sample 

identification on the sample data sheets is given as the sample location, such as SP01, followed by a sample number, 

such as SP0101, followed by the sample depth, such as SP010104-05. The sample identification in the above table 

provides the soil probe location, such as SB-1 for example, followed by the sample depth in feet in parenthesis, for 

example SB-1 (4-5). B Background sample documentation for ESI samples collected in 2000 is provided in Table 1. C Background sample concentration documentation for ESI samples collected in 2000 is provided in Table 2. The values 

in Table 2 were presented in micrograms per kilogram (μg/kg) and are displayed in this table as milligrams per 

kilogram (mg/kg) for consistency. To convert micrograms to milligrams, one must divide micrograms by 1,000 .

mg/kg Milligrams per kilogram

bgs Below ground surface

ft Feet

MDL Method detection limit

ND Not detected

SP Sampling point

GP Geoprobe point
Source No: 1

37 Source Characterization

2.2.3 HAZARDOUS SUBSTANCES AVAILABLE TO A PATHWAY

Containment values are based on an observed release from source area to ground water and the absence of 

any documented containment features. Much of the subsurface soil contamination is covered by 

buildings or gravel or concrete pavement (Ref 34, p. 47). The containment factor values for Source 1 are 

provided in Table 10.

TABLE 10

CONTAINMENT SOURCE 1

Containment Description

Containment 

Factor Value References

Gas release to air: Not scored

Particulate release to air: Not scored

Release to ground water: Monitoring well samples provide evidence of hazardous 

substance migration from the source area, and none of the following is known to 

be present, nor were documented by deep soil borings, at the source: liner, 

maintained engineered cover, functioning and maintained run-on control system 

and runoff management system, or functioning leachate collection and removal 

system immediately above a liner. The depth to water at the site ranges from 10.6 

to 13.8 feet below the top of monitoring well casings (Ref. 34, p. 57). Potential 

dense non-aqueous phase liquids (DNAPL) were found from approximately 8 to 

34.5 feet below ground surface in the vicinity of source 1 (Ref. 34, pp. 36, 91). 

The tool used to detect DNAPL was designed specifically to detect tar in the 

subsurface (Ref. 34, p. 17). This suggests DNAPL tar is present below the water 

table.

10 5, pp. 18, 20, 27, 

28, 33, 34, 35;

34, pp. 58, 60, 

86, 88, 91, 277-

294

Release through overland migration: Not scored
Hazardous Waste Quantity

Source No: 1

38 Source Characterization

2.4.2 HAZARDOUS WASTE QUANTITY

2.4.2.1.1 Hazardous Constituent Quantity

The hazardous constituent quantity for Source 1 could not be adequately determined according to the 

HRS requirements; that is, the total mass of all Comprehensive Environmental Response, Compensation, 

and Liability Act (CERCLA) hazardous substances in the source is not known and cannot be estimated 

with reasonable confidence [Ref. 1, pp. 51590-51591 (Section 2.4.2.1.1)]. There are insufficient 

historical and current data (Manifests, PRP records, State records, Permits, Waste concentration data, etc.) 

available to adequately calculate the total or partial mass of all CERCLA hazardous substances in the 

source and the associated releases from the source. Therefore, there is insufficient information to 

evaluate the associated releases from the source to calculate the hazardous constituent quantity for Source 

No. 1 with reasonable confidence.

Hazardous Constituent Quantity Assigned Value: Not scored

2.4.2.1.2 Hazardous Wastestream Value

The hazardous wastestream quantity for Source 1 could not be adequately determined according to the 

HRS requirements; that is, the mass of the hazardous wastestreams and CERCLA pollutants and 

contaminants in the source and releases from the source is not known and cannot be estimated with 

reasonable confidence [Ref. 1, pp. 51591 (Section 2.4.2.1.2)]. There are insufficient historical and current 

data (Manifests, PRP records, State records, permits, etc.) available to adequately calculate the total or 

partial mass of all hazardous wastestreams and CERCLA pollutants and contaminants in the source and 

the associated releases from the source. Therefore, there is insufficient information to evaluate the 

associated releases from the source to calculate the hazardous wastestream quantity for Source No. 1 with 

reasonable confidence.

Hazardous Wastestream Quantity Assigned Value: Not scored

2.4.2.1.3 Volume

The information available is not sufficient to adequately support evaluation of the volume for Source 1 as 

the full depth of contamination was not determined by sampling. 

Volume Assigned Value: 0 (Ref. 1, Section 2.4.2.1.3). 

2.4.2.1.4 Area

As documented in Tables 4 and 9 of this HRS documentation record, soil samples collected from Source 

1 revealed the presence of numerous PAH compounds at concentrations above background levels,

documenting an area of soil contamination. Table 5 of this HRS documentation record summarizes 

observations of contaminated soil. Prior to the November 2013 and June 2014 removal activities, the area 

of contaminated soil was estimated to be 12,447 square feet, as shown on Figure 2 of this HRS 

documentation record and using the samples summarized in Tables 4 and 9 of this HRS documentation 

record. 

Because contaminated soils were excavated during the November 2013 and June 2014 removal activities 

in accordance with the Administrative Settlement Agreement and Order on Consent for Removal Action

(Ref. 46, pp. 4, 9, 28, 37, 38), a conservative value of unknown, but greater than 0 is assigned as the 

Source 1 area assigned value to account for an unknown amount of soil contamination remaining at the 

source, as well as releases from the source to shallow ground water that were not addressed as part of the 

removal activities.

Area of Source (ft2

): Unknown, but >0
Hazardous Waste Quantity

Source No: 1

39 Source Characterization

Equation for Assigning Value (Table 2-5): A/34,000

Area Assigned Value: >0

2.2.4.3 Source Hazardous Waste Quantity Value

The source hazardous waste quantity value is assigned the value for area of contaminated soil.

Highest assigned value assigned from Table 2-5: >0
40 Source Characterization

Table 11 provides a summary of the Source 1 hazardous waste quantity factor value and containment 

factor values. 

TABLE 11

SUMMARY OF SOURCE DESCRIPTIONS

Source 

Number

Source 

Hazardous 

Waste 

Quantity 

Value

Source 

Hazardous 

Constituent 

Quantity 

Complete? 

(Y/N)

Containment Factor Value by Pathway

GW

(Table 3-2)

SW Air

Overland/flood

(Table 4-2)

GW to SW

(Table 3-2)

Gas

(Table 6-3)

Particulate 

(Table 6-9)

1 >0 N 10 NS NS NS NS

Notes:

GW = Ground water

NS = Not scored

SW = Surface water

Description of Other Possible Sources

There are no other known source areas at the INL&P facility. 
41 GW - General

3.0 GROUND WATER MIGRATION PATHWAY

3.0.1 GENERAL CONSIDERATIONS

Site Geology

The EE/CA completed for INL&P included an investigation of ground water and site geology. Electrical 

conductivity (EC) probing was conducted to delineate the lithology of the subsurface of INL&P. EC 

probing is able to distinguish fine-grained from coarse-grained unconsolidated material that may indicate 

preferential pathways for contaminant migration. The probes were intended to be advanced to bedrock; 

however, bedrock was not encountered before refusal within glacial till. The depth to till is between 14.6 

and 31.1 feet bgs (Ref. 34, p. 15).

The geology at INL&P is described in the EE/CA as follows: Alluvium and glacial till underlay INL&P. 

The upper portion of the alluvium consists mostly of stiff, low plasticity sandy or silty clay. The lower 

portion of the alluvium is composed of a medium- to course-grained sand with a few discontinuous clay 

lenses. One particular clay lens is present within the sand layer underneath a portion of INL&P at 

approximately 26 feet bgs. This clay lens was identified in EC probes EC-9 and EC-3 and was also 

observed in the soil boring for monitoring well MW-2B. The probes and monitoring well locations are 

shown in Figure 2-1, page 75 of Reference 34. However, the lens was not identified in any other EC 

probe or soil boring, which indicates the lens is not continuous throughout INL&P. Underlying the 

alluvium is glacial till composed mostly of very stiff sandy or silty clay. Soft, sandy clay was 

encountered below the sandy alluvium at monitoring well MW-3B. This material was distinctly different 

than the glacial till encountered at all of the other monitoring well locations. Based on the response of 

probe EC-02, it appears this material is approximately 8 feet thick. Because of the high clay content, this

material is likely not a preferential pathway and does not alter the general site conceptual model (Ref. 34, 

p. 23). Geologic cross sections developed from boring and EC logs are shown on Figures 3-1, page 77, 

and 3-2, page 78 of Reference 34. 

Geotechnical testing conducted as part of the EE/CA indicates that the bulk density and hydraulic 

conductivity of the shallow soil at the facility as determined from a sample collected from 5 to 7 feet bgs 

using American Society for Testing and Materials (ASTM) Method D5084-00 was lean clay with an 

average hydraulic conductivity of 3.73 x 10-5 centimeters per second (cm/sec) and a bulk density of 95.6 

pounds per cubic foot (Ref. 34, p. 24). The laboratory data sheet associated with the geotechnical testing 

is located in Appendix I (page 438) of Reference 34.

Ground water levels were measured in all the INL&P monitoring wells during the EE/CA field 

investigation in July 2009. The depth to ground water at each well relative to the top of casing and the 

corresponding ground water elevation are presented in Table 3-1, page 57 of Reference 34. The ground 

water levels were used to generate potentiometric surface maps for water levels measured from both the 

“A” and “B” wells, Figure 3-3, page 79 of Reference 34, and Figure 3-4, page 80 of Reference 34. These 

maps indicate an east/southeast direction of ground water flow in the surficial aquifer across INL&P. The 

water levels indicate a negligible vertical gradient at wells MW-1A/B, MW-4A/B, and MW-6A/B. There 

is a slight upward gradient at wells MW-2A/B and MW-3A/B, indicating that the screened intervals are 

separated by a less permeable layer. This thin clay layer was observed and recorded in the boring logs. A 

slight downward gradient exists at wells MW-5A/B and MW-7A/B, which are the two southernmost 

wells. A downward gradient is typical of an area of recharge within the aquifer and indicates downward 

flow (Ref. 34, p. 26). 

The EE/CA included a slug test data evaluation to calculate hydraulic conductivity. Calculated hydraulic 

conductivity ranges from 1.41 x 10-3 cm/sec in well MW-1A to 2.11 x 10-1 cm/sec in well MW-5B. The 
42 GW - General

average hydraulic conductivity of the upper portion of the alluvial sand is 9.18 x 10-3 cm/sec and 1.56 x

10-2 cm/sec for the lower portion of the alluvial sand. The horizontal flow velocities were calculated to be 

45 feet per year in the upper portion of the alluvial sand and 86 feet per year in the lower portion of the 

alluvial sand (Ref. 34, p. 26). The slug test and ground water calculation sheets are presented in 

Appendix H (page 386) of Reference 34.

Ground Water Migration Pathway Description

Aquifer/Stratum 1 (uppermost): Surficial Alluvial Deposits

The soils at INL&P are classified as Muir silty clay loam. These soils are nearly level (0 to 1 percent 

slopes) on low stream terraces. The Muir silty clay loams are well drained, have surface runoff classified 

as slow, and have moderate permeability. These soils formed from silty alluvium in the flood plain of the 

Elkhorn River (Ref. 11, pp. 7, 9, 10, 11).

Norfolk is located on the alluvial plains of the Elkhorn River and its tributary, the North Fork of the 

Elkhorn River (Refs. 3; 11, p. 9). The unconsolidated materials underlying Norfolk consist of Quaternary 

age stream alluvium (sand, gravel, and silty clay) deposited by the Elkhorn River and North Fork of the 

Elkhorn River (Ref. 11, p. 3). Static water level measured during the ESI conducted in 2000 was 

approximately 14 feet bgs (Ref. 5, pp. 57, 58). The northwestern portion of Norfolk is underlain by 

glacial till and loess deposits, creating gently sloping to steep hills (Ref. 11, pp. 3, 9, 11). The 

unconsolidated materials are of Quaternary age and have an approximate thickness of 40 to 50 feet in the 

North Fork Elkhorn River flood plain (Refs. 3; 10, pp. 34, 35; 11, p. 3). The alluvial and glacial deposits 

form a surficial aquifer, from which nearby private wells and municipal wells near the West Water 

Treatment Plant draw potable water supplies. The primary sources of ground water in Madison County 

are the sands and gravels of the surficial alluvial deposits that overlie the bedrock through most of the 

county. Well depths in the Elkhorn Valley commonly range from 50 to 150 feet. Depths to water 

generally range from 10 to 20 feet near the Elkhorn River to as much as 50 feet along the valley sides. In 

the upland, as much as 200 feet of loess and till may overlie the sand and gravel of the surficial alluvial 

deposits. Wells depths in the uplands generally range from 175 to 300 feet and water levels generally 

range from 75 to 175 feet (Ref. 11, p. 3). 

Aquifer/Stratum 2 (lowest): Niobrara Chalk

The unconsolidated sands and gravels of the surficial alluvial deposits are underlain by Cretaceous age 

Niobrara chalk (Refs. 11, p. 3; 10, pp. 12, 35). This unit is estimated to be from 100 to 200 feet thick and 

consists of marine chalky shale and chalk that is light- to medium-gray and yellow (Ref. 18, pp. 3, 4). 

Ground water is derived from open fractures, crevices, and solution cavities within the chalk, and the 

water withdrawn from the chalk is replaced by recharge from the overlying unconsolidated surficial 

alluvial deposits (Refs. 18, p. 3; 11, p. 4). The Niobrara chalk is not extensively used for water supplies 

(Ref. 11, p. 4). The unconsolidated sands and gravels of the surficial alluvial deposits and the chalk 

formation are considered interconnected and will be evaluated as one hydrologic unit. Municipal well 

logs for G-49313 (west), G-70116 (east) indicate that sands directly over lie chalk rock or are separated 

by a thin (less than three-feet-thick) stringer of clay(Refs. 10, pp. 12, 34, 35, 87, 88, 93) A generalized 

stratigraphic column of the local geology is presented as Figure 5-1 in the ESI report (Ref. 5, p. 30). 

Table 12 provides a summary of aquifers evaluated at the site. 

As shown in Reference 3, all target wells within the four mile target distance limit are within the broad 

alluvial floodplains of the North Fork Elkhorn River and the Elkhorn River. There are no known geologic 

features that completely transect the surficial alluvial deposits and Niobrara Chalk formation.
43 GW - General

 

TABLE 12

SUMMARY OF AQUIFER(S) BEING EVALUATED

Aquifer 

Number Aquifer Name

Is Aquifer Interconnected 

with Upper Aquifer within 

2 miles? (Y/N/NA)

Is Aquifer 

Continuous within 4-

mile TDL? (Yes/No)

Is Aquifer 

Karst? 

(Yes/No)

1 Surficial Alluvial Deposits

(Alluvium)

Not applicable Yes No

2 Niobrara Chalk Yes Yes No
44 GW – Likelihood of Release

3.1 LIKELIHOOD OF RELEASE

3.1.1 OBSERVED RELEASE

Direct Observation

Soil borings collected from the facility contained tar. The depth to water at the site ranges from 10.6 to 

13.8 feet below the top of monitoring well casings (Ref. 34, p. 57). Potential dense non-aqueous phase 

liquids (DNAPL) were found from approximately 8 to 34.5 feet below ground surface in the vicinity of 

Source 1 (Ref. 34, pp. 36, 91). The tool used to detect DNAPL was designed specifically to detect tar in 

the subsurface (Ref. 34, p. 17). This suggests DNAPL tar is present below the water table.

Chemical Analysis

Establishing an observed release by chemical analysis requires analytical evidence of a hazardous 

substance in the medium at a concentration significantly above the background level. If the background 

concentration is not detected (or is less than the detection limit), an observed release is established when 

the sample measurement equals or exceeds its own sample quantitation limit (SQL) and that of the 

background sample. If the SQL cannot be established, the EPA contract-required quantitation limit 

(CRQL) is used in place of the SQL for samples analyzed under the EPA Contract Laboratory Program 

(CLP), or the detection limit for sample not analyzed under the EPA CLP (Ref. 1, Section 2.3, Table 2-3). 

All hazardous substances listed in the ground water observed release tables meet these criteria. 

Basis for Chemical Analysis:

Data collected during the ESI and the EE/CA ground water investigation from on-facility monitoring 

wells and temporary monitoring wells document an observed release by chemical analysis to the 

interconnected shallow surficial alluvial deposits (alluvium) and Cretaceous age Niobrara chalk aquifer 

systems (Refs. 5; 34, p. 85). The data from the ESI and EE/CA investigations used to document an 

observed release to the interconnected shallow surficial alluvial deposits and Cretaceous age Niobrara 

chalk systems are discussed in the sections below. This aquifer system will be referred to as the 

interconnected alluvium and Niobrara chalk aquifer system. 

An observed release by chemical analysis also is supported by the 1992 sampling conducted by HDR 

Engineering, Inc. During the 1992 sampling, three monitoring wells (MW-101, MW-104, and MW-106) 

were sampled and analyzed for VOCs, SVOCs, metals, and cyanides (Ref. 7, pp. 7, 18, 30, 45, 47, 58-74). 

However, this investigation is not used to document an observed release to the aquifer because the data 

are more than 15 years old. 

Expanded Site Inspection: Observed Release by Chemical Analysis:

As documented in the sections below, the data collected during the ESI documents an observed release to 

the interconnected alluvium and Niobrara chalk aquifer systems by extensive distribution of clean 

background temporary monitoring wells screened in the same aquifer at similar depths as the release 

wells (Ref. 5, pp. 19, 56-64, 68-72, 130). The ESI field activities were conducted by E&E between 

March 19 and 25, 2000, and were completed in accordance with the site-specific QAPP (Refs. 5, p. 13; 

13). During the ESI field work, 20 ground water samples were collected and analyzed using the mobile 

laboratory in accordance with the START MLP QAPP. Fourteen DPT ground water confirmatory 

samples were submitted to the EPA Region 7 laboratory for confirmation analysis (Ref. 5, pp. 13, 18, 19, 

56-64, 68-72, 83, 130, 206 - 209). All municipal well samples and private well samples were submitted 

for analysis (Ref. 5, pp. 13, 130). Appendices B and C of Reference 5 provide a copy of the chain-ofcustody form, field sheets, and analytical data (Ref. 5, pp. 55 - 210). Samples collected by START were 

analyzed by the EPA Region 7 laboratory under ASR number 539, activity number TJC13 (Ref. 5, pp. 
45 GW – Likelihood of Release

128, 131). The laboratory analyzed the samples in accordance with EPA Region 7 SOP 1640.1A, EPA 

Region 7 Laboratory Quality Assurance Project Plan (Ref. 13, p. 29). SVOCs were analyzed in 

accordance the EPA Region 7 SOP 3230.2B for extraction and analysis of water and solids for SVOC,

dated February 1995. VOCs were analyzed in accordance with EPA Region 7 SOP 3230.1C, GC/MS 

Analysis for VOCs, dated October 1993. The metals were analyzed in accordance the EPA Region 7 

SOP 3122.2B, analysis for metals by TJA ICAP 61, April 1995 (Ref. 13, p. 31). The data were validated 

in accordance with procedures outlined in Section 6.5 of Reference 13 (Ref. 13, p. 34). The chain-of 

custody form for the samples collected during the ESI and sent to the EPA Region 7 laboratory is 

provided as Appendix B of Reference 5, pages 124 to 127. The logbook notes documenting sampling are 

provided as Appendix D (page 211) of Reference 5. 

During the ESI, ground water samples were collected from six municipal wells (wells 1 through 5, and 

10), and four private or commercial wells (Ref. 15, pp. 1, 2, 9). All samples from private and municipal 

wells were analyzed by the EPA Region 7 laboratory for drinking water VOCs (Refs. 5, pp. 128, 130, 

132, 149, 155, 160; 15, pp. 2, 9). In addition, ground water samples were collected from temporary 

monitoring wells. Twenty locations were sampled from a 4-foot-long screen at depths of either 18 to 22, 

29 to 33, 33 to 37, or 36 to 40 feet bgs (Ref. 15, pp. 2, 6). A ground water sample was collected at each 

location and analyzed by an on-site field laboratory for benzene and target PAH compounds including 

naphthalene, benzo(a)anthracene, benzo(b)fluoranthene, benzo(k)fluoranthene, and benzo(a)pyrene (Ref. 

15, p. 2). Fourteen samples from 12 of these locations were also submitted to the EPA Region 7 

laboratory for confirmation analysis (Ref. 15, p. 9). A ground water sample was also collected from 

monitoring well PG-1. It is believed that this well is the same as well MW-101 that was installed and 

sampled as part of the 1992 investigation (Refs. 15, pp. 2, 6, 9; 13, p. 20; 7, p. 7). The other two 

monitoring wells installed previously could not be located during the ESI (Ref. 5, p. 19).
46 GW – Likelihood of Release

Expanded Site Inspection Background Concentrations:

During the ESI, background concentrations in temporary monitoring wells are represented by wells GP-4,

GP-5, GP-8, GP-11, and GP-30. As shown on Figure 3-2 of the ESI report, wells GP-4, GP-5, and GP-8 

are all located west- northwest of INL&P (Ref. 5, p. 18). GP-11 is located northeast and GP-30 is located 

south (Ref. 5, p. 18). Temporary wells GP-4, GP-5, GP-11, and GP-30 were screened at a depth of 18 to 

22 feet bgs and well GP-8 was screened at a depth of 33 to 37 feet bgs (Ref. 5, pp. 57, 58, 59, 70, 72). 

The temporary wells were not surveyed; therefore, an elevation of the screened interval is not provided. 

The field sheets documenting the sample collection date and time are provided in Appendix B of 

Reference 5 (Ref. 5, p. 55). Appendix B also provides the chain-of-custody records for the background 

samples. 

These wells were chosen as background wells because they are upgradient or in some cases side gradient 

of Source 1 (Refs. 15, Figure 2, p. 6; 5, pp. 18, 19, 21, 29, 31, 41; 34, pp. 79, 80). Temporary wells GP-4, 

GP-5, GP-11, GP-8, and GP-30 are located approximately, 0.06, 0.04, 0.14, 0.19 and 0.04 mile

upgradient/cross-gradient from Source 1, respectively. (See Figure 2 of this HRS documentation record; 

Ref. 15, p. 6) The ground water samples collected from the background and release wells were collected 

from similar depths in the aquifer (screened intervals), as documented in Tables 13 and 15 below. The 

field sheets rather than logbooks were used to document sample collection time and locations in Tables 13 

and 15. The samples were collected during the same time frame using the same sample collection 

procedures and analytical methods (Ref. 5, pp. 19, 21). The construction details for the background 

monitoring wells are provided in Table 13 below. Table 14 below summarizes the concentrations of 

hazardous substances detected in the background wells. The samples were assigned laboratory sample 

numbers on the chain-of-custody form (Ref. 5, pp. 124 - 127; 15, pp. 9, 10). The laboratory sample

numbers are used on the analytical data sheets to identify the sample. 

TABLE 13

2000 EXPANDED SITE INSPECTION

BACKGROUND MONITORING WELL CONSTRUCTION DETAILS

Sample 

Identification

Laboratory Sample 

Identification

Screened Interval

(ft bgs) Date Reference

GP-4 2 18 - 22 3/22/00 5, pp. 57, 130

GP-5 3 18 - 22 3/22/00 5, pp. 58, 130

GP-11 15 18 - 22 3/25/00 5, pp. 70, 130

GP-30 17 18 - 22 3/25/00 5, pp. 72, 130, 234

GP-8 4 33 - 37 3/24/00 5, pp. 59, 130, 216, 229, 233

Notes:

bgs Below ground surface

ft Feet

GP Geoprobe
47 GW – Likelihood of Release

TABLE 14

2000 EXPANDED SITE INSPECTION BACKGROUND CONCENTRATIONS

Sample 

Identification Hazardous Substance

Concentration

(μg/L)

Sample 

Quantitation 

Limit (μg/L) References

GP-4

(Laboratory 

Sample 2)

Acenaphthene

Acenaphthylene

Anthracene

Benzo(a)anthracene

Benzo(a)pyrene

Benzo(b)fluoranthene

Benzo(g,h,i)perylene

Benzo(k)fluoranthene

Chrysene

Fluoranthene

Fluorene

Indeno(1,2,3-c,d)pyrene

2-Methylnaphthalene

Naphthalene

Phenanthrene

Pyrene

2.0 U

2.0 U

2.0 U

2.0 U

2.0 U

2.0 U

2.0 U

2.0 U

2.0 U

2.0 U

2.0 U

2.0 U

2.0 U

2.0 U

2.0 U

2.0 U

2.0

2.0

2.0

2.0

2.0

2.0

2.0

2.0

2.0

2.0

2.0

2.0

2.0

2.0

2.0

2.0

5, pp. 57, 124, 130, 133, 134, 135; 

45, pp. 4, 5

GP-5

(Laboratory 

Sample 3)

Acenaphthene

Acenaphthylene

Anthracene

Benzo(a)anthracene

Benzo(a)pyrene

Benzo(b)fluoranthene

Benzo(g,h,i)perylene

Benzo(k)fluoranthene

Chrysene

Fluoranthene

Fluorene

Indeno(1,2,3-c,d)pyrene

2-Methylnaphthalene

Naphthalene

Phenanthrene

Pyrene

2.0 U

2.0 U

2.0 U

2.0 U

2.0 U

2.0 U

2.0 U

2.0 U

2.0 U

2.0 U

2.0 U

2.0 U

2.0 U

2.0 U

2.0 U

2.0 U

2.0

2.0

2.0

2.0

2.0

2.0

2.0

2.0

2.0

2.0

2.0

2.0

2.0

2.0

2.0

2.0

5, pp. 58, 124, 130, 133, 134; 45, 

pp. 7, 8
48 GW – Likelihood of Release

TABLE 14

2000 EXPANDED SITE INSPECTION BACKGROUND CONCENTRATIONS

Sample 

Identification Hazardous Substance

Concentration

(μg/L)

Sample 

Quantitation 

Limit (μg/L) References

GP-11

(Laboratory 

Sample 15)

Acenaphthene

Acenaphthylene

Anthracene

Benzo(a)anthracene

Benzo(a)pyrene

Benzo(b)fluoranthene

Benzo(g,h,i)perylene

Benzo(k)fluoranthene

Chrysene

Fluoranthene

Fluorene

Indeno(1,2,3-c,d)pyrene

2-Methylnaphthalene

Naphthalene

Phenanthrene

Pyrene

2.0 U

2.0 U

2.0 U

2.0 U

2.0 U

2.0 U

2.0 U

2.0 U

2.0 U

2.0 U

2.0 U

2.0 U

2.0 U

2.0 U

2.0 U

2.0 U

2.0

2.0

2.0

2.0

2.0

2.0

2.0

2.0

2.0

2.0

2.0

2.0

2.0

2.0

2.0

2.0

5, pp. 70, 127, 130, 143, 144, 217; 

45, p. 41, 42

GP-30

(Laboratory 

Sample 17)

Acenaphthene

Acenaphthylene

Anthracene

Benzo(a)anthracene

Benzo(a)pyrene

Benzo(b)fluoranthene

Benzo(g,h,i)perylene

Benzo(k)fluoranthene

Chrysene

Fluoranthene

Fluorene

Indeno(1,2,3-c,d)pyrene

2-Methylnaphthalene

Naphthalene

Phenanthrene

Pyrene

2.0 U

2.0 U

2.0 U

2.0 U

2.0 U

2.0 U

2.0 U

2.0 U

2.0 U

2.0 U

2.0 U

2.0 U

2.0 U

2.0 U

2.0 U

2.0 U

2.0

2.0

2.0

2.0

2.0

2.0

2.0

2.0

2.0

2.0

2.0

2.0

2.0

2.0

2.0

2.0

5, pp. 72, 130, 147, 148; 45, pp. 

47, 48
49 GW – Likelihood of Release

TABLE 14

2000 EXPANDED SITE INSPECTION BACKGROUND CONCENTRATIONS

Sample 

Identification Hazardous Substance

Concentration

(μg/L)

Sample 

Quantitation 

Limit (μg/L) References

GP-8

(Laboratory 

Sample 4)

Acenaphthene

Acenaphthylene

Anthracene

Benzo(a)anthracene

Benzo(a)pyrene

Benzo(b)fluoranthene

Benzo(g,h,i)perylene

Benzo(k)fluoranthene

Chrysene

Fluoranthene

Fluorene

Indeno(1,2,3-c,d)pyrene

2-Methylnaphthalene

Naphthalene

Phenanthrene

Pyrene

2.0 U

2.0 U

2.0 U

2.0 U

2.0 U

2.0 U

2.0 U

2.0 U

2.0 U

2.0 U

2.0 U

2.0 U

2.0 U

2.0 U

2.0 U

2.0 U

2.0

2.0

2.0

2.0

2.0

2.0

2.0

2.0

2.0

2.0

2.0

2.0

2.0

2.0

2.0

2.0

5, pp. 59, 130, 133, 134; 45, pp. 

10, 11

Notes:

GP Geoprobe ground water sample 

ND Not detected

μg/L Micrograms per liter

U Not detected at or above the reportable level shown (Ref. 5, p. 129).
50 GW – Likelihood of Release

2000 Expanded Site Inspection - Contaminated Samples:

During the ESI, releases of hazardous constituents related to INL&P were reported in municipal, 

monitoring, and temporary monitoring wells, all located hydrologically downgradient of INL&P. During 

the ESI, temporary and permanent monitoring well samples were analyzed for low detection limit VOCs, 

dissolved metals, total cyanide, and SVOCs (Ref. 15, p. 9). Samples from private and municipal wells 

were analyzed for drinking water VOCs, ethylene dibromide (EDB), dibromochloropropane (DBCP), 

total and dissolved metals, total cyanide, SVOCs, and PAHs (Ref. 15, p. 9). The temporary monitoring 

wells that contained elevated levels of contaminants were GP-3, GP-23, and GP-28. All of these wells

were located east and downgradient of INL&P (see Figure 2 page 6 of Reference 15) (Ref. 15, p. 6). 

Temporary wells GP-23, and GP-28 were screened at a depth of 18 to 22 feet bgs (Ref. 5, pp. 60, 62). 

The temporary wells were not surveyed; therefore, an elevation of the screened interval is not provided. 

The construction details for the release monitoring wells are provided in Table 15 below. Table 16 below 

summarizes the concentrations of hazardous substances detected in the release wells. The samples were 

assigned laboratory sample numbers on the chain-of-custody (Refs. 5, pp. 124 - 127; 15, pp. 9, 10). 

Direction of ground water flow at INL&P is east-southeast (Ref. 5, pp. 29, 31). Therefore, the release 

wells are located hydrologically downgradient of Source 1. The sample identifications are used on the 

analytical data sheets to identify the sample. 

TABLE 15

2000 EXPANDED SITE INSPECTION 

RELEASE MONITORING WELL CONSTRUCTION DETAILS 

Sample 

Identification

Laboratory Sample 

Number

Screened Interval

(ft bgs) Date References

GP-3 1 20 - 24 3/21/00 15, pp. 6, 9; 5, pp. 56, 130

GP-23 5 18 - 22 3/24/00 15, pp. 6, 9; 5, pp. 60, 130

GP-28 7 18 - 22 3/24/00 15, pp. 6, 9; 5, pp. 62, 130

Notes:

bgs Below ground surface

ft Feet

GP Geoprobe ground water sample

MW Monitoring well
51 GW – Likelihood of Release

TABLE 16

2000 EXPANDED SITE INSPECTION RELEASE CONCENTRATIONS

Sample 

Identification Hazardous Substance Concentration 

Sample 

Quantitation 

Limit (SQL)

Background 

ConcentrationA

(SQL)

(see Table 14) References

Units: (μg/L)

GP-3

(Laboratory 

Sample 1)

Acenaphthene

Acenaphthylene

Anthracene

Benzo(a)anthracene

Benzo(a)pyrene

Benzo(b)fluoranthene

Benzo(g,h,i)perylene

Benzo(k)fluoranthene

Chrysene

Fluoranthene

Fluorene

Indeno(1,2,3-c,d)pyrene

2-Methylnaphthalene

Naphthalene

Phenanthrene

Pyrene

360

700

300

160

130

60

43

77

190

310

230

42

140

400

1,200

530

10

10

10

10

10

10

10

10

10

10

10

10

10

10

10

10

ND (2)

ND (2)

ND (2)

ND (2)

ND (2)

ND (2)

ND (2)

ND (2)

ND (2)

ND (2)

ND (2)

ND (2)

ND (2)

ND (2)

ND (2)

ND (2)

5, pp. 56, 130, 

133, 134; 45, 

pp. 1, 2

GP-23

(Laboratory 

Sample 5)

Acenaphthene

Acenaphthylene

Naphthalene

33

5.4

49

2.0

2.0

2.0

ND (2)

ND (2)

ND (2)

5, pp. 60, 130, 

136, 137, 138; 

45, pp. 13, 14

GP-28

(Laboratory 

Sample 7)

Acenaphthene

Acenaphthylene

Anthracene

Benzo(a)anthracene

Benzo(a)pyrene

Benzo(k)fluoranthene

Chrysene

Fluoranthene

Fluorene

2-Methylnaphthalene

Naphthalene

Phenanthrene

Pyrene

290

280

85

21

25

15

25

69

130

92

690

280

97

10

10

10

10

10

10

10

10

10

10

10

10

10

ND (2)

ND (2)

ND (2)

ND (2)

ND (2)

ND (2)

ND (2)

ND (2)

ND (2)

ND (2)

ND (2)

ND (2)

ND (2)

5, pp. 62, 130, 

136, 137, 138; 

45, pp. 19, 20, 

21

Notes:

A The background concentrations and sample quantitation limits (SQL) are documented in Table 14 of this HRS 

documentation record. As documented in Table 14, the SQL for the semivolatile organic compounds such as 

acenaphthene is 2 μg/L. 

GP Geoprobe ground water sample

ND Not detected

μg/L Micrograms per liter
52 GW – Likelihood of Release

Ground Water Sampling - Engineering Evaluation/Cost Analysis (EE/CA)

The EE/CA field investigation occurred in November and December 2007, June and July 2009, and 

January 2010. The field activities were completed as specified in the work plan, technical memorandum 

1, and field sampling plan (Refs. 37; 38; 40). Table 2-1 outlines significant deviations to the planned 

work (Ref. 34, pp. 14, 55). 

The ground water field investigation included advancing laser-induced fluorescence (LIF) and ground 

water probes; installing and developing monitoring wells; measuring ground water elevations; collecting 

ground water samples; and surveying. Sampling included collection of ground water samples from 

direct-push probes and from newly installed monitoring wells for chemical analysis. The EE/CA field 

activities were designed to gather data to better define and characterize the subsurface geology and site 

hydrogeology and the approximate extent of DNAPL and dissolved-phase ground water contamination at 

the INL&P (Ref. 34, p. 14). Aquifer testing also was performed (Ref. 34, p. 16). 

Fourteen ground water probes were advanced on INL&P and three samples were collected from each 

probe, for a total of 42 ground water samples, to delineate the horizontal and approximate vertical extent 

of ground water contamination (Ref. 34, pp. 17, 29). The samples were analyzed for PAHs by SW-846 

Method 8270-SIM and for VOCs by SW-846 Method 8260B. All PAH data were reported as Level II 

quality data. Figure 2-1, page 75 of Reference 34 shows the probe locations (Ref. 34, p. 17). 

In November and December 2007, ground water probes were advanced to refusal within the glacial till. 

An attempt was made to collect a sample at the refusal depth. If no water was present, the probe was 

retracted and a sample was collected at the interface of the sand and till. The probe was then retracted to 

the midpoint of the sand unit or to a depth where potential DNAPL was indicated by LIF probing to 

collect the “intermediate” sample. The probe was retracted a third time to collect the sample at the top of 

the sand unit. This procedure was used for the ground water probes advanced west of 6th Street. 

Although the potentiometric surface was measured at approximately 12 feet bgs, it was within a silty clay 

unit that did not produce much water. Therefore, the shallow sample was collected at the top of the sand 

unit (Refs. 34, pp. 17, 18, 85, 277 - 294). 

Water was present in the till unit for ground water probe samples collected east of 6th Street. Therefore, 

the “deep” sample was collected from the point of probe refusal in the till. The probe was then retracted 

and a sample was collected from the interface of the sand and till to evaluate whether contamination was 

sinking and pooling on top of the till downgradient from the site. The probe was again retracted to the top 

of the sand, where the third, shallow sample was collected (Ref. 34, p. 18).

Monitoring wells were installed in soil borings with 81⁄2-inch outside diameter (OD), 41⁄4-inch inside 

diameter hollow stem augers. Each boring was continuously sampled by driving 2-foot split-spoon 

samplers. The borings were logged to record stratigraphy and visible contamination and were screened 

for VOCs with a PID and the results recorded on the boring logs. Two nested monitoring wells were 

installed at each location to monitor the upper and lower portions (designated with the letters “A” and 

“B”) of the surficial aquifer. Table 2-2, page 56 of Reference 34 lists the depth and screened interval for 

each newly installed well. All wells are constructed of 2-inch OD Schedule 40 polyvinyl chloride pipe 

with 0.010-inch wide factory slots. Shallow wells have 9.5-foot screens and the deep wells have 4.8-foot 

screens (Ref. 34 p. 18). Ground water samples were collected in July 2009 (Ref. 34, pp. 85, 295 – 315, 

341 – 354). 

The EE/CA ground water sampling investigation was performed in July 2009. All monitoring wells were 

purged and sampled in accordance with the QAPP (Ref. 38) using low-flow sampling procedures. Before 

sampling, the wells were allowed to equilibrate with the surrounding formation and ground water levels

were measured. In addition, wells MW-2A and MW-2B were measured for light and dense nonaqueous 
53 GW – Likelihood of Release

phase liquid. Also during purging, field measurements [dissolved oxygen (DO), oxidation-reduction 

potential (ORP), pH, temperature, turbidity, and specific conductivity were recorded. No field parameters 

were measured for wells where there was an oily sheen on the water (wells MW-2A and MW-2B) (Ref. 

34, p. 19). The ground water sampling forms for each well are presented in Appendix G of Reference 34.

After wells were purged, ground water samples were collected from each monitoring well for chemical 

analysis of VOCs by SW-846 Method 8260B, PAHs by SW-846 Method 8270 - SIM, selected total 

metals (arsenic, barium, cadmium, chromium, and lead) by SW-846 Method 6010B, and total and 

amenable cyanide by SM 4500CN-E/4500CN-G. All BTEX, PAH, and cyanide data were reported as 

Level IV quality data. Existing monitoring well MW-104 was not found during the EE/CA field 

investigation (Ref. 34, pp. 19, 20). 

Fifteen ground water samples were collected from 14 ground water monitoring wells. All samples were 

analyzed for BTEXs, PAHs, and inorganic constituents (arsenic, barium, cadmium, chromium, lead, and 

cyanide) (Ref. 34, p. 29). The analytical results from the monitoring well samples are used to document 

an observed release to ground water. The samples collected from the ground water probes are not used to 

document an observed release to ground water because the ground water samples were not collected from 

properly installed monitoring wells. The ground water probe samples contained VOCs and PAHs (Ref. 

34, pp. 30, 31). 

EE/CA DNAPL Delineation:

The EE/CA also included delineation of the approximate horizontal and vertical extent of potential 

DNAPL in the saturated portion of the subsurface. The delineation involved advancing 18 probes 

equipped with a LIF tool designed specifically to detect tar in the subsurface. The LIF tool detects tar by 

emitting a laser light that causes electrons in the tar to excite and fluoresce. A sensor on the LIF tool then 

measures the intensity of the fluorescence to provide a qualitative result on the amount present. In 

general, the stronger the signal, the more likely tar is present. The LIF probe locations were selected 

based on the locations of historical MGP structures from Sanborn Maps and historical investigation 

results (Refs. 34, p. 17; 37, p. 8). The locations of the LIF probes are shown on Figure 2-1, page 75 of 

Reference 34, and the LIF logs and data files are included in Appendix D of Reference 34. In addition, 

three soil probes (SP-5, SP-6, and SP-8) were advanced and continuously sampled and logged to verify 

data obtained with the LIF probes (Ref. 34, p. 17).

Probes LIF-01, LIF-03, LIF-06, LIF-07, LIF-08, and LIF-09 were advanced near historical MGP 

structures. As shown in Table 4-6, page 63 of Reference 34, these probes indicate potential DNAPL from 

approximately 8 to 34.5 feet bgs. No DNAPL was identified below approximately 25 feet in the probes 

advanced south of the alley that bisects INL&P, likely a result of the presence of the clay lens identified 

during EC probing and previously discussed. However, probes LIF-02, LIF-04, LIF-14, and LIF-15, east 

of INL&P, indicate potential DNAPL below 25 feet. Probes LIF-02, LIF-04, LIF-14, and LIF-15 are 

located approximately 60 feet, 112 feet, 130 feet, and 135 feet from Source 1 (Figure 2 of this HRS 

documentation record; Ref. 34, p. 75). This finding suggests that the clay layer is not continuous east of 

7th Street. The thickness of the potential DNAPL indicated by the LIF probes decreases significantly east 

of INL&P. No DNAPL was indicated in probes LIF-05, LIF-10, LIF-11, LIF-12, LIF-13, LIF-16, LIF17, or LIF-18, indicating that DNAPL has not migrated downgradient of these locations and is confined 

to INL&P (Ref. 34, pp. 36, 37). The LIF logs are presented in Appendix C of Reference 34. 

The approximate extent of DNAPL contamination as of 2009 is shown in Figure 4-11, page 91 of 

Reference 34.
54 GW – Likelihood of Release

Background Concentrations: 

Each monitoring well was installed as nested pairs one well screened in the shallow and one screened in 

the deeper portions of the alluvium during the 2009 EE/CA ground water investigation. Monitoring wells 

screened in the shallow portion of the alluvium were assigned the prefix A, and the monitoring wells 

screened in the deeper portion have the prefix B. Well MW-1A is the background well for the shallow 

portion of the alluvium, and MW-1B is the background well for the deep portion of the alluvium. The 

locations of the monitoring wells are shown in Reference 34, Figure 2-1 page 75. These wells were 

chosen as background because they are upgradient of Source 1 (Ref. 34, Figure 3-3, p. 79 and Figure 3-4, 

p. 80). The ground water samples from the background and release wells were collected from similar 

depths in the aquifer (screened intervals), as documented in Table 17 below. The samples were collected 

during the same time frame using the same sample collection procedures and analytical method (Refs. 34, 

p. 19; 37; 38). The construction details for both the background and the release monitoring wells are 

provided in Table 17 below. 

The concentrations of hazardous substances detected in the background wells are summarized in Table 18

for the wells screened in the shallow portion of the aquifer and in Table 19 for the wells screened in the 

deeper portion of the aquifer. 
55 GW – Likelihood of Release

TABLE 17

EE/CA MONITORING WELL DEPTH AND SCREENED INTERVAL

Monitoring 

WellA

Sample 

Date

Total 

Depth Screened Interval

TOC 

Elevation

Depth 

to 

Water

Ground 

Water 

Elevation Reference 34

(ft bgs) (ft bgs) (ft above msl) (msl) (ft btoc) (msl)

MW-1A 07/08/2009 20.2 10.3–19.8 1502.9 – 1512.4 1522.35 10.62 1511.73 pp. 56, 57, 295, 341, 372

MW-1B 07/08/2009 28.0 23–27.8 1495.0 – 1499.8 1522.31 10.60 1511.71 pp. 56, 57, 296, 297, 342, 373

MW-2A 07/07/2009 26.4 16.5–26 1495.9 - 1505.4 1521.43 11.41 1510.02 pp. 56, 57, 298, 343, 374

MW-2B 07/07/2009 34.5 29.5–34.3 1487.9 – 1492.7 1521.55 11.41 1510.14 pp. 56, 57, 299, 300, 344, 375

MW-3A 07/06/2009 26.1 16.2–25.7 1498.1 – 1507.6 1523.00 13.73 1509.27 pp. 56, 57, 301, 345, 376

MW-3B 07/06/2009 38.0 32.8–37.6 1486.2 – 1491.0 1523.48 13.67 1509.81 pp. 56, 57, 302, 303, 346, 377

MW-4A 07/07/2009 25.0 15.1–24.6 1499.1 – 1508.6 1523.22 13.73 1509.49 pp. 56, 57, 304, 347, 378

MW-4B 07/07/2009 33.0 28–32.8 1490.8 – 1495.6 1523.23 13.72 1509.51 pp. 56, 57, 305, 306, 348, 378

MW-5A 07/07/2009 20.3 10.4–19.9 1502.9 – 1512.4 1522.40 13.77 1508.63 pp. 56, 57, 307, 349, 380

MW-5B 07/07/2009 35.6 30.6–35.4 1487.4 – 1492.2 1522.34 13.80 1508.54 pp. 56, 57, 308, 309, 350, 381

MW-6A 07/07/2009 23.2 13.3–22.8 1498.0 – 1507.5 1520.54 12.75 1507.79 pp. 56, 57, 310, 351, 382

MW-6B 07/07/2009 32.3 27.3–32.1 1488.7 – 1493.5 1520.51 12.71 1507.80 pp. 56, 57, 311, 312, 352, 383

MW-7A 07/07/2009 23.1 13.2–22.7 1496.8 – 1506.3 1519.17 11.76 1507.41 pp. 56, 57, 313, 353, 384

MW-7B 07/07/2009 32.5 27.5–32.3 1487.2 – 1492.0 1519.11 11.84 1507.27 pp. 56, 57, 314, 315, 354, 385

Notes:

A Wells designated with an “A” monitor ground water within the upper portion of the surficial aquifer. Wells designated with a “B” monitor ground water at the base of the 

surficial aquifer. MW-1A is the background well for wells screened in the shallow portion of the alluvium, and well MW-1B is the background well for wells screened in the 

deeper portion of the alluvium. 

bgs Below ground surface

btoc Below top of casing

ft Feet

msl Mean sea level

MW Monitoring well

TOC Top of casing
56 GW – Likelihood of Release

TABLE 18

EE/CA BACKGROUND CONENTRATION – SHALLOW GROUND WATER

Sample

Identification

Laboratory 

Sample 

Identification Hazardous Substance

Concentration

(μg/L)

Method 

Detection 

Limit 

(μg/L)

Reference 

34

MW-1A MW1AWOP1P Benzo(a)pyrene ND 0.051 p. 544

MW-1A MW1AWOP1P Benzo(b)fluoranthene ND 0.051 p. 544

MW-1A MW1AWOP1P Benzo(g,h,i)perylene ND 0.051 p. 544

MW-1A MW1AWOP1P Dibenzo(a,h)anthracene ND 0.051 p. 544

MW-1A MW1AWOP1P Fluoranthene 0.12 0.051 p. 544

MW-1A MW1AWOP1P Phenanthrene ND 0.051 p. 544

Notes

< Analyte was not detected at or above the method detection limit, which is presented.

MW Monitoring well

μg/L Microgram per liter

ND Analyte was not detected at or above the method detection limit (Ref. 34, p. 60)

TABLE 19

EE/CA BACKGROUND CONENTRATION – DEEP GROUND WATER

Sample

Identification

Laboratory 

Sample 

Identification

Hazardous Substance Concentration

(μg/L)

Method 

Detection 

Limit (μg/L)

Reference 34

MW-1B MW1BWOP1P Acenaphthene ND 0.05 p. 546

MW-1B MW1BWOP1P Acenaphthylene ND 0.05 p. 546

MW-1B MW1BWOP1P Benzo(a)anthracene ND 0.05 p. 546

MW-1B MW1BWOP1P Benzo(a)pyrene ND 0.05 p. 546

MW-1B MW1BWOP1P Benzo(b)fluoranthene ND 0.05 p. 546

MW-1B MW1BWOP1P Benzo(g,h,i)perylene ND 0.05 p. 546

MW-1B MW1BWOP1P Benzo(k)fluoranthene ND 0.05 p. 546

MW-1B MW1BWOP1P Fluoranthene 0.087 0.05 p. 547

MW-1B MW1BWOP1P Naphthalene 0.13 0.05 p. 547

MW-1B MW1BWOP1P Phenanthrene ND 0.05 p. 547

Notes:

< Analyte was not detected at or above the method detection limit, which is presented.

MW Monitoring well

μg/L Microgram per liter

ND Analyte was not detected at or above the method detection limit (Ref. 34, p. 60)
57 GW – Likelihood of Release

Release Concentrations:

The concentrations of hazardous substances that meet the criteria for documenting an observed release to 

ground water are summarized in Table 20for wells screened in the shallow portion of the alluvium and in 

Table 21 for wells in the deep portion of the alluvium. Tar-saturated sand was encountered in the soil 

boring retrieved from well MW-2B (Ref. 34, pp. 299, 300). Tar was encountered in the boring from well 

MW-6B (Ref. 34, p. 311). 

TABLE 20

EE/CA RELEASE CONENTRATION – SHALLOW GROUND WATER

(Background Monitoring Well MW-1A)

Sample

Identification Hazardous Substance

Concentrations

(adjusted 

concentration)

(μg/L)

Method 

Detection 

Limit (μg/L)

Background 

Concentration

(μg/L)

(see Table 18)

Reference

34

MW-2A

MW-6A

Benzo(a)pyrene 1.4

0.090

0.052

0.051

<0.051 p. 550

p. 568

MW-2A

MW-6A

Benzo(b)fluoranthene 1.4

0.10

0.052

0.051

<0.051 p. 550

p. 568

MW-2A Benzo(g,h,i)perylene 0.57 0.052 <0.051 p. 550

MW-2A Dibenzo(a,h)anthracene 0.12 0.052 <0.051 p. 551

MW-2A

MW-3A

MW-4A

MW-6A

MW-7A

Fluoranthene 10.9

1.6

3.8

0.80

0.58

0.052

0.051

0.054

0.051

0.05

0.12 p. 551

p. 555

p. 559

p. 568

p. 572

MW-2A

MW-3A

MW-4A

MW-6A

Phenanthrene 37.6J (3.76)

11.7

37.1J (3.71)

3.2

0.052

0.051

0.054

0.051

<0.051 p. 551

p. 555

p. 559

p. 568

Notes:

MW-1A is the background well for these wells. The background and release wells are screened in the shallow portion of the 

alluvium. 

The ground water samples with estimated concentrations (J laboratory data qualified) are adjusted according to the EPA fact 

sheet Using Qualified Data to Document an Observed Release and Observed Contamination, Reference 44. The concentrations 

are divided by the adjustment factor value because the bias is unknown (Ref. 44, p. 8). The adjustment factors are benzene 1.64 

and phenanthrene 10 (Ref. 44, pp. 11, 14, 15). The concentration in parenthesis is the adjusted concentrations. 

< Analyte was not detected at or above the method detection limit, which is presented.

( ) Adjusted concentration (Ref. 44)

J Estimated concentration (Ref. 34, pp. 60, 615), the concentration in parenthesis is the adjusted concentration (Ref. 44).

MW Monitoring well

μg/L Microgram per liter
58 GW – Likelihood of Release

TABLE 21

EE/CA RELEASE CONENTRATION – DEEP GROUND WATER

(Background Monitoring Well MW-1B)

Sample

Identification Hazardous Substance

Concentrations

(adjusted 

concentration)

(μg/L)

Method 

Detection 

Limit (μg/L)

Background 

Concentration

(μg/L)

(see Table 19)

Reference

34

MW-2B

MW-4B

MW-5B

MW-7B

Acenaphthene 30.3J (8.34)

86.3J (23.77)

0.81

77.8J (21.43)

0.052

0.054

0.053

0.052

<0.05 p. 553

p. 561

p. 566

p. 574

MW-2B

MW-3B

MW-4B

MW-5B

MW-7B

Acenaphthylene 20.8

1.6

4.5

0.055

3.8

0.052

0.052

0.054

0.053

0.052

<0.05 p. 553

p. 557

p. 561

p. 566

p. 574

MW-2B Benzo(a)anthracene 0.45 0.052 <0.05 p. 553

MW-2B Benzo(a)pyrene 0.18 0.052 <0.05 p. 553

MW-2B Benzo(b)fluoranthene 0.19 0.052 <0.05 p. 553

MW-2B Benzo(g,h,i)perylene 0.073 0.052 <0.05 p. 553

MW-2B

MW-3B

MW-4B

MW-7B

Fluoranthene 9.5

0.37

2.8

0.61

0.052

0.052

0.054

0.052

0.087 p. 553

p. 557

p. 561

p. 574

MW-2B

MW-4B

MW-7B

Naphthalene 5.4

48.9J (4.89)

19.1

0.052

0.054

0.052

0.13 p. 553

p. 561

p. 574

MW-2B

MW-3B

MW-4B

MW-5B

MW-7B

Phenanthrene 42.5

1.3

38.9J (3.89)

0.41

21.2J (2.12)

0.052

0.052

0.054

0.053

0.052

<0.05 p. 553

p. 557

p. 561

p. 566

p. 574

Notes:

MW-1B is the background well for these monitoring wells. The background and release wells are screened in the deep portion of 

the alluvium. 

The ground water samples with estimated concentrations (J laboratory data qualified) are adjusted according to the EPA fact 

sheet Using Qualified Data to Document an Observed Release and Observed Contamination, Reference 44. The concentrations 

are divided by the adjustment factor value because the bias in unknown (Ref. 44, p. 8). The adjustment factors are acenaphthene 

3.63; naphthalene 10; and phenanthrene 10 (Ref. 44, pp. 14, 15).

< Analyte was not detected at or above the method detection limit, which is presented.

( ) Adjusted concentration (Ref. 44)

J Estimated concentration (Ref. 34, pp. 60, 615), the concentration in parenthesis is the adjusted concentration (Ref. 44).

MW Monitoring well

μg/L Microgram per liter
59 GW – Likelihood of Release

Attribution

The Iowa-Nebraska Light and Power Company operated under numerous names in Norfolk, Nebraska, 

from about 1907 through the mid- to late-1940s (Refs. 6, p. 3; 8, pp. 8, 9; 9. During this time, the facility 

operated as a manufactured gas plant (Ref. 7, pp. 3, 5). Operations at the facility used fossil fuel (coal 

and oil) as a feedstock to produce a combustible gaseous product that was used for lighting and heating 

(Refs. 8, p. 9; 9, pp. 3-5). The manufacturing process generated several byproducts including tars, 

sludges, tar liquors and ammonia liquor, spent iron oxide ash, slag, and clinkers (Ref. 19, pp. 3 - 32). The 

coal tars are composed of polycyclic aromatic hydrocarbons (PAHs), phenolic compounds, light aromatic 

compounds, and small quantities of inorganic constituents (Refs. 8, pp. 9, 11; 19, pp. 9 through 14). In 

the early years from 1900 to 1924, the facility used a Tenney and Springer process (Ref. 9, pp. 2 - 24). 

Between 1926 and 1930, the process was described as water gas (Ref. 9, pp. 25 - 29). Between 1932 and 

1935, the process was described as carbureted water gas (Ref. 9, pp. 30 - 33). 

Generators produced a combustible gas using coke, steam, and oil products (Ref. 39, p. 6). As the gas 

cooled through the production process, coal tar would fall from suspension in the gas and become a waste 

product (Ref. 39, p. 6). A scrubber was used to condense the gas (Ref. 39, p. 6). Coal tar was ultimately 

separated from the condensate water (Ref. 39, p. 6). Purifier boxes were used to remove sulfides and 

cyanides from the cool gas. Iron oxides were mixed with fluffing material (primarily wood chips, 

sawdust and corncobs) in the purifier boxes to provide for additional removal of water vapor and coal tar 

with the associated hydrogen sulfide and cyanide (Ref. 39, p. 6). After the gas was manufactured, it was 

stored in gas holders. Coal tar residuals were also present in the gas holders (Ref. 39, p. 6).

Some of the waste resulting from the production of the manufactured gas, including coal tar, was sold. 

Some wastes were disposed of at the facility (Ref. 39, p. 7). Coal tar is primarily composed of PAHs, 

phenolic compounds, light aromatic compounds, various inorganics and various sulfides (Ref. 39, pp. 6, 

7). In December 1990, Ecology and Environment, Inc. (E&E), completed a preliminary assessment (PA) 

at INL&P to assess potential sources of contamination. The PA provided site-related background 

information, estimates of possible waste quantities produced, and a summary of nearby targets (Ref. 6, pp. 

1 to 4). The PA postulated that PAH and cyanide waste may have been disposed of to the ground (Ref. 6, 

p. 8). In June 1992, HDR Engineering Inc. (HDR) of Omaha, Nebraska, conducted a site investigation 

(SI) of INL&P for Minnegasco, Inc. Eighteen soil samples were collected from six soil borings, and four 

ground water samples were collected from three monitoring wells installed during field operations. The 

six borings referred to as NOR-101 through NOR-106, were located near former facility features to 

investigate the possibility that releases of associated wastes to soil had occurred in the past (Ref. 7, pp. 6, 

7, 8). As documented in Section 2 of this HRS documentation record, soil samples collected at the 

facility contained elevated concentrations of the same constituents as were reported in ground water 

samples collected from on-site monitoring wells and temporary monitoring wells. Background wells did 

not indicate other potential sources of coal tar related hazardous constituents in the immediate site 

vicinity. There are no other known source areas at the INL&P facility. The EE/CA described 29 leaking 

underground storage tank sites within 0.5 mile of the facility and 16 underground storage tanks within 

0.25 mile (Ref. 34, pp. 12, 13, 98, 99, 100). These leaking underground storage tanks may be 

contributing petroleum related constituents to area. Ground water flow is to the east, south east (Ref. 34, 

pp. 79, 80, 85-88). Most of the USTs and/or LUST sites are located downgradient of both the source and 

temporary wells used to establish the observed release and/or are located upgradient of background 

samples used in the scoring (Ref. 34, p. 105; Figure 2 of this HRS documentation record). 

Evidence of releases from the former MGP operations to ground water is evidenced in the presence of 

DNAPL in ground water underlying and downgradient of the contaminated soil source, as documented in 
60 GW – Likelihood of Release

the EE/CA ground water investigation (Ref. 34, pp. 36, 37). The approximate extent of DNAPL 

contamination is shown in Figure 4-11, page 91 of Reference 34.

Hazardous Substances Released

Acenaphthene Benzo(a)pyrene Chrysene 2-Methylnaphthalene

Acenaphthylene Benzo(b)fluoranthene Fluorene Naphthalene

Anthracene Benzo(g,h,i)perylene Fluoranthene Phenanthrene

Benzo(a)anthracene Benzo(k)fluoranthene Indeno(1,2,3-c,d)pyrene Pyrene

Ground Water Observed Release Factor Value: 550
61 GW – Waste Characteristics

3.2 WASTE CHARACTERISTICS

3.2.1 Toxicity/Mobility

Table 22 summarizes the toxicity and mobility values and combined factor value for the hazardous 

substances associated with Source 1. All hazardous substances listed in Table 22 have been documented 

in either soil or ground water samples from Source 1. These hazardous substances were detected at 

concentrations significantly exceeding background levels. 

TABLE 22

TOXICITY/MOBILITY FACTOR VALUES

Hazardous Substance

Source 

Number

Toxicity 

Factor 

Value

Mobility 

Factor 

Value*

Does Hazardous 

Substance Meet 

Observed Release?**

Toxicity/ Mobility 

Factor Value

(Ref. 1, Table 3-9) Reference

Acenaphthene 1 10 1* Yes 10 2, p. 3

Acenaphthylene 1 1 1* Yes 1 2, p. 3

Anthracene 1 10 1* Yes 10 2, p. 3

Benzo(a)anthracene 1 1,000 1* Yes 1,000 2, p. 3

Benzo(a)pyrene 1 10,000 1* Yes 10,000 2, p. 4

Benzo(b)fluoranthene+ 1 --- 1* Yes --- 2, p. 4

Benzo(g,h,i)perylene 1 0 1* Yes 0 2, p. 4

Benzo(k)fluoranthene 1 100 1* Yes 100 2, p. 4

Chrysene 1 10 1* Yes 10 2, p. 5

Fluoranthene*** 1 100 1* Yes 100 2, p. 4

Fluorene 1 100 1* Yes 100 2, p. 7

Indeno(1,2,3-c,d)pyrene 1 1,000 1* Yes 1,000 2, p. 9

2-Methylnaphthalene 1 1,000 1* Yes 1,000 2, p. 9

Naphthalene 1 1,000 1* Yes 1,000 2, p. 9

Phenanthrene 1 1 1* Yes 1 2, p. 10

Pyrene 1 100 1* Yes 100 2, p. 10

Notes:

* Liquid, non-karst mobility factor value used, or if substance was found in an observed release to ground water, then a 

mobility factor value of 1 is assigned (Ref. 1, Sec. 3.2.1.2).

** See section 3.1.1 of this HRS documentation record

*** This compound is listed as its synonym benzo(j,k)fluorene in Reference 2 + Compound not listed in Reference 2

Benzo(a)pyrene is the hazardous substances with the highest toxicity and mobility factor value, of 10,000.

Toxicity/Mobility Factor Value: 1x104

(Ref. 1, Table 3-9)
62 GW – Waste Characteristics

3.2.2 Hazardous Waste Quantity

Table 23 provides a summary of the source hazardous waste quantity values. 

TABLE 23

SUMMARY OF SOURCE HAZARDOUS WASTE QUANTITY VALUES

Source Number Source Type Source Hazardous Waste Quantity

1 Contaminated Soil >0

Sum of Values: >0

In accordance with Section 2.4.2.2, a minimum value of 10 was used for the Hazardous Waste Quantity 

Factor Value because Hazardous Constituent Quantity has not been adequately determined for Source 1, 

and none of the targets for the ground water pathway is subject to Level I or Level II concentrations (Ref. 

1, Sec. 2.4.2.2).

Hazardous Waste Quantity Factor Value: 10

(Ref. 1, Section 2.4.2.2)

3.2.3 Waste Characteristics Factor Category Value

Toxicity/Mobility Factor Value: 10,000

Hazardous Waste Quantity Factor Value: 10

Toxicity/Mobility Factor Value ×

Hazardous Waste Quantity Factor Value: 100,000 or 1 × 105

Waste Characteristics Factor Category Value: 18

(Ref. 1, Table 2-7)
63 GW – Targets

3.3 TARGETS

The public water supplies for the City of Norfolk are provided by the City of Norfolk public water supply 

system consisting of two water treatment plants supplied by two well fields. The two fields have a total 

of 11 active wells (Refs. 17, pp. 1, 2; 27; 41; 43). The water treatment plants are referred to as the east 

and west water treatment plants (Refs. 17, p. 1; 41, p. 1). Wells serving the west water treatment plant 

range in depth from 50 to 65 feet below ground surface (Ref. 17, pp. 1 - 8, 14). The last right-hand 

column of Reference 17, pages 1 and 2, identifies the plant that receives the flow from the supply wells. 

Number 001 indicates the east water treatment plant (facility number 001) and number 002 indicates the 

west water treatment plant (facility number 002) (Ref. 17, pp. 1, 2). Wells serving the east water 

treatment plant range in depth from 101 to 120 feet below ground surface (Ref. 17, pp. 2, 11 - 13). Wells 

serving the west water treatment plant are screened in unconsolidated sands and gravel (Ref. 10, pp. 1 –

12, 40-48, 62, 63). A boring log for a well serving the east water treatment plant indicates that the well is 

finished as an uncased and unscreened hole in chalk formation (Ref. 10, pp. 34, 35). 

Eight municipal wells (wells 681, 682, 692, 691, 752, 751, 921, and 20031) are associated with the west 

treatment plant, and three wells (wells 281, 471, and 551) are associated with the east treatment plant 

(Refs. 17, pp. 1, 2; 43, pp. 3, 4). Two other municipal wells (wells 291 and 301) formerly were 

associated with the east treatment plant and have been taken out of service because of contamination 

thought to be associated with a leaking underground storage tank (LUST) (Refs. 43, pp. 1, 2, 3; 20, p. 2; 

34, pp. 12, 13, 74, 98 - 100; 10, pp. 18, 22). Municipal 291 is currently being used as a remediation well, 

and municipal well 301 was idled because of benzene contamination (Refs. 20, p. 2; 43, p. 1). According 

to the City Water superintendent, there are 9,352 service connections (Ref. 36). According to the City 

Water superintendent, the population served is 24,210 (Refs. 12, p. 1; 36). The City also sells water to 

two subdivisions outside the city limit, the Eastern Heights, subdivision where water is provided to about 

80 homes and the Suburban Acres subdivision where the city provided water to about 30 homes (Ref. 36). 

In total the city provides water to a city and subdivision population of 24,472 (Ref. 36). Table 24

presents information for the City of Norfolk municipal wells.

TABLE 24

CITY OF NORFOLK WATER SUPPLY WELLS

State 

Registration 

Number

Other 

Identifier

Status,

Water 

Treatment 

Plant Served

Location

Township, 

Range, Section

Total 

Depth

(feet)

Screen depth

(feet bgs)

Capacity

(gpm)

Date 

Drilled

References

G-029258 68-1

(681)

Well 7

Active, West 24N, 2W, 25ad 50.67 30'8" - 50'8" 750 03/09/68 17, pp. 1, 

3; 10, pp. 

1, 2

G-029259 68-2

(682)

Well 1

Active, West 24N, 2W, 25ad 59 29 – 59 1,000 03/12/68 17, pp. 1, 

4; 10, pp. 

3, 4

G-049057 69-2

(692)

Well 9

Active, West 24N, 1W, 30cb 57 27 – 57 1,000 10/30/69 17, pp. 2, 

5; 10, pp. 5 

- 7; 21, p. 4

G-049058 69-1

(691)

Active, West 24N, 1W, 30cb 57 27 – 57 1,000 10/29/69 17, pp. 2, 

6; 10, pp. 

8, 9;

G- 049312 75-2

(752)

Active, West 24N, 1W, 30cd 55.5 20 – 56 1,000 04/18/75 17, pp. 2, 

7; 10, pp. 

10, 11, 61; 

21, p. 4
64 GW – Targets

TABLE 24 (Continued)

CITY OF NORFOLK WATER SUPPLY WELLS

State 

Registration 

Number

Other 

Identifier

Status,

Water 

Treatment 

Plant Served

Location

Township,

Range, Section

Total 

Depth

(feet)

Screen depth

(feet bgs)

Capacity

(gpm)

Date 

Drilled

References

G-049313 75-1

(751)

Well 10

Active, West 24N, 1W, 30ca 55.5 –Unknown 1,000 04/24/75 17, pp. 2, 8; 

10, pp. 12, 

13; 21, p. 4

G-070112 21-1

(291)

Well 1

Inactive, East 24N, 1W, 26bb 130 Not Reported 930 08/29/29 17, pp. 2, 9; 

10, pp. 18 -

21; 21, p. 4

G-070113 30-2

(301)

Well 2

Inactive, East 24N, 1W, 26bb 127 Not Reported 860 10/14/30 17, pp. 2, 

10; 10, pp. 

22 - 25; 21, 

p. 4

G-070114 26-3

(281)

Well 3

Active, East 24N, 1W, 26bb 94

(120)

Not Reported 520 08/21/28 17, pp. 2, 

11; 10, pp. 

26 - 29; 21, 

p. 4

G-070115 47-4

(471)

Well 4

Active, East 24N, 1W, 26bb 101 Not Reported 670 10/11/47 17, pp. 2, 

12; 10, pp. 

30 - 33; 21, 

p. 4

G-070116 54-1

(551)

Well 5

Active, East 24N, 1W, 26bb* 117 45 – 117 1,220 02/05/55 17, pp. 2, 

13; 10, pp. 

34, 35; 21, 

p. 4

G-074818 (921)

(Well 12)

Active, West 24N, 1W, 31 65 40 – 60 800 03/04/92 17, pp. 2, 

14; 10, pp. 

40, 41, 42, 

47, 48

G-122246 (20031) Active, West 24N, 1W, 31 69.5 60 – 67 4,000 08/17/02 17, pp. 2, 

15; 10, pp. 

62, 63

Notes:

* The well registration form indicates the well is in section 27 (Ref. 10, p. 34). The wells location in section 27 is 

substantiated by the off-site sample location map in the ESI (Ref. 5, p. 18) and by other consultants work in Norfolk 

(Refs. 30, pp. 2 – 7; 31, p. 2).

bgs Below ground surface

gpm Gallons per minute

In addition to the city population served, the Norfolk public water supply also serves the primary and 

secondary schools of the Norfolk public school system (Refs. 22; 25, pp. 13, 17, 18, 19, 20, 23, 24, 28, 

31, 41, 47, 48, 50, 51, 53, 54, 58, 59, 60, 61, 66). (Note: Reference 25 provides the sampling points [SP] 

for the City of Norfolk distribution system.) According to on-line data from 2013-2014, the Norfolk 

school district has a student enrollment of 4,162 students and 270 staff (Ref. 24, pp. 3, 5). Current 

information for students, faculty and staff indicates a population of 4,814 (Ref. 36). The system also 

serves the Norfolk Catholic Schools, with a 2013-2014 enrollment of 639 students and a staff of 40 (Refs. 

24, p. 4, 6; 25, pp. 12, 27, 49, 58, 60). Current staff and student population is 669 (Ref. 36). The system 

serves St. Paul Lutheran Elementary school (2013-2014 enrollment of 98 students and 4 staff) (Refs. 24, 
65 GW – Targets

p. 8; 25, p. 10). Current staff and student population is 154 (Ref. 36). In addition, the following postsecondary education institutions are served by the system: the Northeast Community College (enrollment 

of 5,035) (Refs. 25, p. 20; 26, p. 9). The student population presented for Northeast Community college 

also includes several satellite campuses. Current student enrollment for the Norfolk campus is 2,954, and 

faculty and staff is 1,100 for a total of 4,054 (Ref. 36). Northeast Community College is identified as 

Tech College in Reference 25. The college is located in the City of Norfolk and is served by the City of 

Norfolk public water supply system (Ref. 35). In total, the system serves at least 34,163 residents and 

students and staff in the City of Norfolk. This number represents the city and two subdivision 

populations served by the system (24,472) and the sum of the students and staff provided above (Ref. 36). 

According to the city, water from the east and west treatment plants is part of a common distribution 

system. The combined pumping capacity for the system is 10,000 gallons per minute (Refs. 27; 43, p. 1). 

Based on the well capacities presented in Table 24 above, no one well contributes more than 40 percent of 

the total demand to the system; therefore, the population served by each well is apportioned equally 

among the 11 active wells, for a population per well of 3,105 (Ref. 1, Section 3.3.2). All 11 wells were 

considered eligible. The two closed wells were not considered. It should be noted that the capacities 

listed for the wells in Table 24 were reported on well registration forms completed at the time of 

installation and may not correspond to the actual current pumping rates of the wells (Ref. 27). 

Other public drinking water supply wells serve the area outside of the City of Norfolk. Information 

obtained from the well logs for those wells is summarized in Table 25 below. These wells are shown on 

Reference 3. As shown on Reference 3, all wells are located within the same alluvial floodplain as the 

city of Norfolk wells. A review of the well logs provided in Reference 10 shows that the drinking water 

supply wells within a 4 mile radius of INL&P are completed or screened within alluvium, the alluvium 

and chalk, or chalk. Because ground water moves freely between the alluvium and chalk, the ground 

water within both of these formations is evaluated as a single hydrologic unit, the interconnected alluvium 

and Niobrara chalk aquifer system, as documented earlier in the HRS documentation record. Therefore, 

the populations served by each of the public water supply wells obtain drinking water supplies from the 

interconnected alluvium and Niobrara chalk aquifer system. The populations served by each well are 

summarized in Section 3.3.2.4, Table 27. 

TABLE 25

PUBLIC WATER SUPPLIES WITHIN 4 MILES OF SOURCE 1

(EXCLUDING THE CITY OF NORFOLK SUPPLY WELLS)

Owner

State Registration 

Number

Other 

Identifier

Total 

Depth

Screen 

depth

(feet bgs)

Capacity

(gpm)

Date 

Drilled Reference

Norfolk Regional

Center

G-068492 Well #5 94 feet 3 

inches

69 - 94 390 06/11/1956 10, pp. 64, 66

Norfolk Regional

Center

G-068493 Well #7 66 feet 50 - 66 470 08/31/1967 10, pp. 68, 70

Norfolk Regional

Center

G-068494 Well #6 56 feet 40 - 56 520 08/29/1967 10, pp. 72, 74, 75

Madison County 

SID#3

G-073538 Well 681 90 feet 38 - 90 75 09/28/1968 10, pp. 76, 78, 79

Madison County 

SID#3

G-043601 Well 751 96 feet 60 - 96 500 12/19/1974 10, pp. 80, 82

Sherwood Medical 

(currently Covidien)

G-102698 Well 621 69 feet 59 - 69 350 05/1962 10, pp. 83, 84, 

85, 86, 87, 88
66 GW – Targets

TABLE 25

PUBLIC WATER SUPPLIES WITHIN 4 MILES OF SOURCE 1

(EXCLUDING THE CITY OF NORFOLK SUPPLY WELLS)

Screen 

State Registration Other Total depth Capacity Date 

Owner Number Identifier Depth (feet bgs) (gpm) Drilled Reference

Sherwood Medical G-102699 Well 751 70 feet 53 - 67 100 11/1975 10, pp. 89, 90, 

(currently Covidien) 91, 92, 93

Sleepy Hollow Acres G-119312 -- NA NA 20 1996 10, p. 94

Notes: 

bgs Below ground surface

gpm Gallons per minute

NA Not available

3.3.1 Nearest Well

The closest drinking water well to the INL&P is Norfolk municipal well 5, registration number G0700116 

(Ref. 15, p. 6). Reference 30 page 2 clearly shows that city water well 5 is located between First and 

Second Street and Norfolk avenue and Madison Avenue. This well was measured at 2,530 feet or 0.48 

mile east of the Source 1 (Refs. 3; 30, p. 2 29).

Well ID: Municipal Well 5

Level of Contamination (I, II, or potential): Potential

If potential contamination, distance from the source in miles: The Norfolk Municipal well 5 is located 

between 1st and 2nd Streets and Norfolk and Madison Avenues (Ref. 15, p. 6). The location of the well is 

more precisely shown on figures from a 1998 preliminary subsurface assessment report prepared for the 

Nebraska Department of Environmental Quality (Ref. 30, pp. 2 - 7). The distance from this well to 

sample location SB-3 at the eastern edge of the INL&P is 2,530 feet or 0.48 mile (Ref. 29). In accordance 

with Section 3.3.1 and Table 3-11 of the HRS rule, a nearest well factor value of 18 is assigned (Ref. 1, 

Section 3.3.1). 

Nearest Well Factor Value: 18 

(Ref. 1, Table 3-11) 
67 GW – Targets

3.3.2 POPULATION

3.3.2.1 Level of Contamination

No Level I or Level II concentrations attributable to the site have been documented at this time. 

3.3.2.2 Level I Concentrations

Not Scored. 

3.3.2.3 Level II Concentrations

Not scored. 

3.3.2.4 Potential Contamination

The public water supply system for the City of Norfolk includes 11 active permanent municipal wells 

(Refs. 17, pp. 1, 2; 27; 41). These wells are reported to range in depth from 50 to 130 feet bgs (Ref. 17, 

pp. 3 - 14). The city has two water treatment facilities referred to as the east and west treatment plants 

(Refs. 17, p. 1; 41, p. 1). Eight municipal wells (wells 681, 682, 692, 691, 752, 751, 921, and 20031) are

associated with the west treatment plant, and three wells (wells 281, 471 and 551) are associated with the 

east treatment plant (Ref. 17, pp. 1, 2). Two other municipal wells (wells 291 and 301) formerly were 

associated with the east treatment plant and have been taken out of service because of contamination 

thought to be associated with a LUST (Refs. 17, p. 2; 20, p. 2; 10, pp. 18, 22; 34, pp. 12, 13, 74, 98 – 100; 

43). Municipal well 1 is currently being used as a remediation well, and municipal well 2 was idled 

because of benzene contamination (Ref. 20, p. 2). The municipal water supply serves the entire 

population of Norfolk (Ref. 12, p. 1). According to the City Water superintendent, the population served 

is 24,210 (Refs. 12, p. 1; 36). The City also sells water to two subdivisions outside the city limit, the 

Eastern Heights, subdivision where water is provided to about 80 homes and the Suburban Acres 

subdivision where the city provided water to about 30 homes (Ref. 36). In total the city provided water to 

24,472 people (Ref. 36).

In addition to the city population served, the Norfolk public water supply also serves the primary and 

secondary schools of the Norfolk public school system (Refs. 22; 25, pp. 13, 17, 18, 19, 20, 23, 24, 28, 

31, 41, 47, 48, 49, 50, 51, 53, 54, 58, 59, 60, 61, 66). (Note: Reference 25 provides the sampling points 

[SP] for the City of Norfolk distribution system. According to on-line data from 2013-2014, the Norfolk 

school district has a student enrollment of 4,162 students and 270 staff (Ref. 24, pp. 3, 5). Current 

information for students, faculty and staff indicates a population of 4,814 (Ref. 36). The system also 

serves the Norfolk Catholic Schools, with an enrollment of 639 students and a staff of 40 (Refs. 24, p. 4, 

6; 25, pp. 12, 27, 49, 58, 60). Current staff and student population is 669 (Ref. 36). The system serves St. 

Paul Lutheran Elementary school (2013-2014 enrollment of 98 students and 4 staff) (Refs. 24, p. 8; 25, p. 

10). Current staff and student population is 154 (Ref. 36). In addition, the following post-secondary 

education institutions are served by the system: the Northeast Community College (enrollment of 5,035) 

(Refs. 25, p. 20; 26, p. 9). The student population presented for Northeast Community college also 

includes several satellite campuses. Current student enrollment for the Norfolk campus is 2,954, and 

faculty and staff is 1,100 for a total of 4,054 (Ref. 36). Northeast Community College is identified as 

Tech College in Reference 25. The college is located in the City of Norfolk that is served by the City of 

Norfolk public water supply system (Ref. 35). In total, the system serves at least 34,163 residents and 

students and staff in the City of Norfolk. This number represents the city and two subdivision 

populations served by the system (24,472) and the sum of the students and staff provided above (Ref. 36). 
68 GW – Targets

According to the city, water from the east and west treatment plants is part of a common distribution 

system. The combined pumping capacity for the system is 10,000 gallons per minute (Ref. 27). Based on 

the well capacities presented in Table 24 in Section 3.3, no one well contributes more than 40 percent of 

the total demand to the system; therefore, the population served by each well is apportioned equally 

among the 11 active wells, for a population per well of 3,105 (Ref. 1, Section 3.3.2). This population is 

entered into Table 26 below for each Norfolk well. All 11 wells were considered eligible. The two 

closed wells were not considered. 

In addition to the City of Norfolk wells, there are numerous other community water supplies within the 

4-mile radius of the INL&P facility. The locations of the wells serving these water supplies are 

documented in Reference 31 and are shown on Reference 3. The populations served by these systems 

come from Reference 32. Because all wells for each of these systems fall within the same distance ring, 

apportionment of population has not been determined.

In addition to the populations included in this scoring, there are numerous additional worker populations 

present within the City of Norfolk community (Refs. 47, 48). 
69 GW – Targets

TABLE 26

POPULATIONS SERVED BY GROUND WATER

Distance 

Category 

(miles)

Well

(Well Registration Number) Population Reference

Distance-Weighted

Population Value

(Ref. 1, Table 3-12)

0 - 1⁄4 None Known

1⁄4 - 1⁄2 Norfolk Municipal Wells

Well #5 (G-070116)

Total 1⁄4 -1⁄2

3,105

3,105

1, Section 3.3.2.4; 3; 

31, p. 2

3,233

1⁄2 - 1 Norfolk Municipal Wells

Well #3 (G-070114)

Well #4 (G-070115)

Total 1⁄2 - 1

3,105

3,105

6,210

1, Section 3.3.2.4; 3;

31, p. 2 1,669

1 – 2 Norfolk Regional Center

Well #5 (G-068492)

Well #7 (G-068493)

Well #6 (G-068494)

Madison Co. SID No. 5

Well 022

Well 021

Total 1 - 2

158

158

158

65

65

604

1, Section 3.3.2.4; 3; 

31, pp. 5, 6; 32, pp. 1 -

4 

94

2 – 3 Madison Co. SID No. 3

Well 681 (G-073538)

Well 751 (G-043601)

Kendall (Covidien) Company

Well 3 (G-102698)

Well 6 (G-102699)

Total 2 - 3

187

188

215

215

805

1, Section 3.3.2.4; 3; 

31, pp. 7, 8; 32, pp. 5 -

8 

68

3 – 4 Norfolk Municipal Wells

Well 681 (G-029258)

Well 682 (G-029259)

Well 692 (G-049057)

Well 691 (G-049058)

Well 752 (G-049312)

Well 751 (G-049313)

Well 921 (G-074818)

Well 20031 (G-122246)

Sleepy Hollow Acres

Well 21 (G-119312)

Total 3 - 4

3,105

3,105

3,105

3,105

3,105

3,105

3,105

3,105

120

24,960

1, Section 3.3.2.4; 3; 

31, pp. 3, 9; 32, p. 9

1,306

Sum of the Distance-Weighted Population Values: 6,370

Sum of Distance-Weighted Population Values: 6,370

Sum of Distance-Weighted Population Values/10: 637

(Ref. 1, Section 3.3.2.4)

Potential Contamination Factor Value: 637
70 GW – Targets

3.3.3 RESOURCES

Ground water within the target distance limit is used for irrigation and commercial food preparation 

(Refs. 5, p. 224; 28, pp. 16, 24, 25, 59, 66; 10 pp. 36 - 39). The pages cited on Reference 28 indicate 

irrigation wells irrigate at least five acres of land. 

Resources Factor Value: 5

3.3.4 WELLHEAD PROTECTION AREA

Observed ground water contamination lies within the State of Nebraska Department of Environmental 

Quality-designated wellhead protection area for the east well field (Ref. 31, p. 2). The wellhead 

protection program is approved by EPA (Ref. 29, p. 8). 

Wellhead Protection Area Factor Value: 20

(Ref. 1, Section 3.3.4)