Record of Decision

Tulsa Fuel & Manufacturing Superfund Site

Collinsville, Tulsa County, Oklahoma

November 2008

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UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

REGION 6

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Record of Decision

Table of Contents Page(s)

Table of Contents.... 2

List of Acronyms and Terms 9

PARTI: THE DECLARATION... .....12

1. SITE NAME AND LOCATION 12

2. , STATEMENT OF BASIS AND PURPOSE.... 12

3. ASSESSMENT OF SITE .13

4. DESCRIPTION OF SELECTED REMEDY ! ...13

5. STATUTORY DETERMINATIONS 13

6. DATA CERTIFICATION CHECKLIST ...14

7. AUTHORIZING SIGNATURES .....15

PART 2: THE DECISION SUMMARY. .16

8. SITENAME, LOCATION, AND BRIEF DESCRIPTION........ 16

9. SITE HISTORY AND ENFORCEMENT ACTIVITIES 16

1. History of Site Activities ....16

2. History of Federal and State Investigations and

Removal and Remedial Actions 17

3. History of CERCLA Enforcement Activities 18

10. COMMUNITY PARTICIPATION... ; 18

11. SCOPE AND ROLE OF RESPONSE ACTION 19

12. SITE CHARACTERISTICS.. , 19

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1. Physical Site Characteristics 19

2. Site Contamination... 21

13. CURRENT AND POTENTIAL FUTURE SITE AND RESOURCE USES 25

1. Current and Future Land Uses..... 25

2. Current and Future Groundwater Uses 25

3. Current and Future Surface Water Uses , 25

14. SUMMARY OF SITE RISKS 25

1. Human Health Risk Assessment 26 I

a. Identification of Chemicals of Concem 1....26 b. Exposure Assessment .....26 c. Toxicity Assessment .27 d. Risk Characterization ,...28 e. ' Uncertainty .....30

2. Ecological Risk Assessment .....30

3. Basis for Response Action 31

15. REMEDIAL ACTION OBJECTIVES :.....31

1. Cleanup Levels..... 32

16. DESCRIPTION OF ALTERNATIVES ......34

1. CommonElementsofRemedial Altematives except

Altemative 1- No Action and 3 - Stabilization and Off-Site Disposal at a

RCRA Permitted Facility 35

2. Summary of Remedial Alternatives 35

a. Altemative 1 - N o Action..., 35

b. On - Site Soil and Waste Material Areas 36

c. Sediment and Surface Water: On - Site Ponds, Mid - Site Ravine,

and Strip Mine Pit 37

d. Soil, Sediment, and Waste: Off-Site Locations 38

17. COMPARATIVE ANALYSIS OF ALTERNATIVES 39 18. PRINCIPAL THREAT WASTES 1 ....43 19. THE SELECTED REMEDY 43

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1. Summary ofthe Rationale forthe Selected Remedy 43

2. Description ofthe Selected Remedy... 44

3. Summary of Estimated Costs .......;..:... 45

4. Expected Outcomes ofthe Selected Remedy 45

20. STATUTORY DETERMINATIONS 46

21. DOCUMENTATION OF SIGNIFICANT; CHANGES ;.52

22. STATE ROLE .....52

PART 3: THE RESPONSIVENESS SUMMARY 53

23. Stake Holder Comments and Agency Responses 53

24. Technical and Legal Issues ...56

REFERENCES .57

TABLES

Table 1 Summary of Chemicals of Concem and Medium-Specific Exposure Point Concentrations 59

Table 2 Summary of Exposure Parameters used in Daily Intake Calculations based on Reasonable Maximum Exposure and Intake Equations - Soil .71

Table 3 Summary of Exposure Parameters used in Daily Intake Calculations based on Reasonable Maximum Exposure and Intake Equations -Groundwater 76

Table 4 Summary of Exposure Parameters used in Daily Intake Calculations based on Reasonable Maximum Exposure and Intake Equations - Air .78

Table 5 Summary of Exposure Parameters used in Daily Intake Calculations based on Reasonable Maximum Exposure and Intake Equations - Surface Water.. 79

Table 6 Summary of Exposure Parameters used in Daily Intake Calculations based on Reasonable Maximum Exposure and Intake Equations - Sediment 82

Table 7 Summary of Exposure Parameters used in Daily Intake Calculations based on

Reasonable Maximum Exposure and Intake Equations - Plant Tissue 85

Table 8 Cancer Toxicity Data Summary - Oral/Dermal 86

Table 9 Cancer Toxicity Data Summary - Inhalation ....86

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Table 10 Non-Cancer Toxicity Data Summary - Oral/Dermal 86

Table 11 Non-Cancer Toxicity Data Summary - Inhalation 86

Table 12 (A-D) Risk Characterization Summaries 12A Risk Characterization Summary - Carcinogenic Risk: On-Site Waste Area

Aduh Resident ,....87

12B Risk Characterization Summary - Non-Carcinogenic Risk: On-Site Waste Area Adult Resident ..: ^ ; ,...87

12C Risk Characterization Summary - Carcinogenic Risk: On-Site Waste Area Child Resident , ,....88

12D Risk Characterization Summary - Non- Carcinogenic Risk: On-Site Waste Area Child Resident 88

12E Risk Characterization Summary - Carcinogenic Risk: On-Site Non-Waste Area Aduh Resident 89

12F Risk Characterization Summary - Non-Carcinogenic Risk: On-Site Non-Waste Area Adult Resident .....90

12G Risk Characterization Summary - Carcinogenic Risk: On-Site Non-Waste Area Child Resident ; 90

12H Risk Characterization Summary - Non- Carcinogenic Risk: On-Site Non-Waste Area Child Resident .....90

121 Risk Characterization Sununary - Carcinogenic Risk: On-Site Waste Area Outdoor Commercial/Industrial Worker. 91

12J Risk Characterization Summary - Non-Carcinogenic Risk: On-Site Waste Area Outdoor Commercial/Industrial Worker .91

12K Risk Characterization Summary - Carcinogenic Risk: On-Site Non-Waste Area Outdoor Commercial/Industrial Worker 92

12L Risk Characterization Summary - Carcinogenic Risk: On-Site Waste Area Commercial/Industrial Worker 92

12M Risk Characterization Summary - Non-Carcinogenic Risk: On-Site Waste Area Constmction/Utility Worker 93

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12N Risk Characterization Summary - Carcinogenic Risk: On-Site Non-Waste Area Constmction/Utility Worker 93

120 Risk Characterization Summary - Carcinogenic Risk: On-Site Waste Area Adolescent Trespasser : ...93

12P Risk Characterization Summary - Non-Carcinogenic Risk: On-Site Waste Area Adolescent Trespasser 94

12Q Risk Characterization Summary - Carcinogenic Risk: Off-Site Adolescent Trespasser 94

12R Risk Characterization Summary - Non-Carcinogenic Risk: Off-Site Adolescent Trespasser 95

12S Risk Characterization Summary - Carcinogenic Risk: Off-Site Adult Resident... ; .: ...:95

12T Risk Characterization Summary - Non-Carcinogenic Risk: Off-Site Adult Resident..... 96

12U Risk Characterization Summary-Carcinogenic Risk: Off-Site Child Resident... 97

12V Risk Characterization Summary - Non-Carcinogenic Risk: Off-Site Child Resident. :..98

Table 13A lEUBK Model Waste Area 100

Table 13B lEUBK Model Non-Waste Area 100

Table 13C Adult Lead Model Waste Area Outdoor Commercial/Industrial Worker 100

Table 13D Adult Lead Model Non-Waste Area Outdoor Commercial/Industrial Worker...... 102

Table 13E Adult Lead Model Waste Area Construction/Utility Worker 103

Table 13F Aduh Lead Model Non-Waste Area Constmction/Utility Worker 104

Table 14 Primary Risk Assessment Uncertainties 105

Table 15 Cleanup Levels for Chemicals of Concem 108

Table 16 Summary of Remedial Altematives Tulsa Fuels and Manufacturing Site 109

Table 17 Evaluation Criteria for Superfund Site Remediation Altematives 110

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Tables 18 (A-G) Detailed Cost Estimates for Remedial Actions

Tables 18: A-E - Cost Estimates for On-Site Soil, Waste Materials, and Sediment Remediation: Altemative 2 - ConsoUdation and Cap

18A - Cost Estimate for 25-Acre Clay Cap with Institutional Controls I l l

18B - Cost Estimate for 10-Acre Clay Cap with Clay Liner and Institutional

Controls............ ..112

18C - Cost Estimate for 10-Acre Clay Cap with Institutional Controls 113

18D - Cost Estimate for 10-Acre Clay Cap with Cmshed Limestone Base and Institutional Controls 114

18E - Cost Estimate for 10-Acre Soil Cap with Cmshed Limestone Base and Institutional Controls 115

18F - Cost Estimate for Off-Site Soil Remediation: Altemative 2 - Excavation, Stabilization (as needed), and Disposal On-Site 117

18G-Cost Estimates for Site Operation and Maintenance 117

Table 19 Action-Specific ARARs... ..........: .118

Table 20 Chemical-Specific ARARs ......: 120

Table 21 Location-Specific ARARs 121

FIGURES

Figure 1 Site Location 122

Figure 2 Major Features at Tulsa Fuel & Manufacturing Site 122

Figure 3 Media and Potential Pathways of Migration at the Tulsa Fuel & Manufacturing Site....

., 123

Figure 4 Human Health Site Conceptual Model 124

Figure 5 Ecological Conceptual Model 125

Figure 6 Area of Concem for On-site Soil and Waste .125

Figure 7 Area of Concem for Sediment and Surface Water 126

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APPENDICES

Appendix A: Record of Communication from Oklahoma Department of Environmental Quality

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LIST OF ACRONYMS AND TERMS

AOC Area of Concem ARARs Applicable or Relevant and Appropriate Requirements ATSDR Agency for Toxic Substances and Disease Registry BHHRA Baseline Human Health Risk Assessment CERCLA Comprehensive Environmental Response, Compensation, and Liability Act COPC Contaminants of Potential Concem COC Contaminants of Concern DEQ Oklahoma Department of Environmental Quality USEPA United States Environmental Protection Agency, Region VI FS Feasibility Study HRS Hazard Ranking System Mg/kg Milligrams per kilogram NCP National Oil and Hazardous Substance Pollution Contingency Plan NPL National Priority List PA Preliminary Assessment PRGs Preliminary Remedial Goals PRP Potentially Responsible Party ROD Record of Decision RAOs Remedial Action Objectives RI Remedial Investigation RCRA Resource Conservation and Recovery Act RME Reasonable Maximum Exposure SI Site Inspection Site Tulsa Fuel and Manufacturing Superfund Site \igfL Microgram per Liter

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Administrative Record - The body of documents available to the public associated with characterization and remedy selection at a site. Applicable or Relevant and Appropriate Requirements (ARARs) - The Federal and State environmental laws that selected remedies will meet. These requirements may vary among sites and altematives. Baseline Human Health Risk Assessment (BHHRA) - An evaluation of the potential threat to human health and the environment in the absence of any remedial action. Carcinogen - Capable of causing the cells ofan organism to react in a manner to produce cancer. Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) -CERCLA was enacted by Congress on December 11, 1980. This law created a tax on the chemical and petroleum industries and provided broad Federal authority to respond directly to releases or threatened releases of hazardous substances that may endanger public health or the environment. Ecological Risk Assessment - Study that assesses risks to aquatic and terrestrial receptors posed by contaminant releases from a site. Excess Lifetime Cancer Risk - Cancer posed by a contaminated site in excess ofthe lifetime probability of developing cancer from other causes. Feasibility Study (FS) - Identifies and evaluates the appropriate technical approaches and treatment technologies to address contamination at a site. Groundwater - Underground water that fills pores in soils or openings in rocks to the point of saturation. Groundwater is often used as a source of drinking water via municipal or domestic •wells. Groundwater Monitoring - Ongoing collection of groundwater information about the environment that helps gauge the effectiveness of a clean-up action. Human Health Risk Assessment - A study that determines and evaluates risk that site contamination poses to human health. Institutional Controls - Actions taken to limit unauthorized access to the site, control the way in which an area of the site is used, and monitor contamination migration. Microgram per Liter (ng/L) - A unit of measurement equivalent to one microgram of contaminant per liter of water. Milligram per Kilogram (mg/kg) - A unit of measurement equivalent to one milligram of contaminant per kilogram of solid (typically soil). National Oil and Hazardous Substance Pollution Contingency Plan (NCP) - Regulations goveming cleanups under USEPA's Superfund program. Preferred Alternative - Final remedial altemative that meets NCP evaluation criteria and is supported by regulatory agencies. Present Value Cost - A method of evaluation of expenditures that occur over different time periods. By discounting all costs to a common base year, the costs for different remedial action altematives can be compared on the basis ofa single figure for each altemative. When calculating present worth cost for Superfund sites, total operations & maintenance costs are to be included. Remedial Action - Action(s) taken to correct or remediate contamination. Remedial Action Objectives (RAOs) -Remediation objectives for protection of human health and the environment.

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Record of Decision (ROD) - A formal document that is a consolidated source of information about a Superfund site, the remedy selection process, and the selected remedy. Receptor - An organism that receives, may receive, or has received environmental exposure to a chemical. Remedial Investigation (RI) - A study conducted to identify the types, amounts, and locations of contamination at a site. Resource Conservation and Recovery Act (RCRA) - The Federal act that established a regulatory system to track hazardous wastes from the time they are generated to their final disposal. RCRA also provides for safe hazardous waste management practices and imposes standards for transporting, treating, storing, and disposing of hazardous waste. Reasonable Maximum Exposure (RME) - The highest level of human exposure that could reasonably be expected to occur.

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Record of Decision

Part 1: The Declaration

1. SITE NAME AND LOCATION

Tulsa Fuel & Manufacturing Superfund Site

Collinsville, Tulsa County, Oklahoma

OKD987096195

2. STATEMENT OF BASIS AND PURPOSE

This decision document presents the selected remedial action for the Tulsa Fuel & Manufacturing Superfund Site (Site), in Collinsville, Tulsa County, Oklahoma. The selected remedial action is chosen in accordance with the Comprehensive Environmental Response, Compensafion and Liability Act of 1980 (CERCLA), 42 U.S.C. § 9601 et seq., as amended by the Superfund Amendments and Reauthorization Act of 1986, and, to the extent practicable, the National Oil and Hazardous Substances Pollution Contingency Plan, 40 CFR Part 300 as amended. The Director ofthe Superfund Division, United States Environmental Protection Agency (EPA) Region 6, is delegated the authority to approve this Record of Decision (ROD).

This decision is based on the Administrative Record, which is developed in accordance with Section 113 (k) of CERCLA, 42 U.S.C. § 9613 (k), and which is available for review at the Collinsville Public Library in Collinsville, Oklahoma, and the Oklahoma Department of Environmental Quality (ODEQ) in Oklahoma City, Oklahoma. The Administrative Record Index identifies each ofthe items comprising the Administrative Record upon which the selection of the remedial action is based.

The State of Oklahoma concurs with the Selected Remedy (Appendix A).

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3. ASSESSMENT OF THE SITE

The response action selected in this ROD is necessary to protect the public health or welfare or the environment from actual or threatened releases of hazardous substances into the environment.

4. DESCRIPTION OF THE SELECTED REMEDY

This ROD sets forth the selected remedy at the Tulsa Fuel & Manufacturing (TFM) Site. The selected remedy is a comprehensive approach and will address the Site as one operable unit. The remedy addresses all current and potential future residential risks associated with exposure to soil, sediment, surface water, and waste. Approximately, 200,000 yd^ ofwaste material, identified as primary source material, will be addressed through on-site consolidation and capping. All references to waste material include soil, sediment, surface water, and waste at the Site. The selected remedy is consistent with proposed future reuse and will allow for restoration of the Site to beneficial uses.

The major component ofthe remedy involves on-site consolidation and capping of soil, sediment, and waste material. The soil, sediment, and waste material may exceed the Toxicity Characteristic Leaching Procedure (TCLP) based on waste material TCLP data results, and therefore, may be characteristic hazardous wastes under 40 CFR § 261.24. Prior to consolidation and capping, TCLP sampling will be conducted on the soil, sediment, and waste material. Based on the results soil, sediment, and waste material may be treated with a high pH substance before being consolidated and capped on-site. The following volumes are estimated for each medium.

a. Soil and Waste Material (On-site): Approximately 164,000 yd^ b. Sediment (On-site): Approximately 33,000 yd^ c. Soil, Sediment, and Waste (Off-site): Approximately 1,600 yd^

5. STATUTORY DETERMINATIONS

The Selected Remedy is protective of human health and the environment, complies with Federal and State requirements that are applicable or relevant and appropriate to the remedial action, is cost-effective, and utilizes permanent solutions and altemative treatment technologies to the maximum extent practicable.

This remedy satisfies the statutory preference for treatment as a principal element ofthe remedy (i.e., reduces the toxicity, mobility, or volume of hazardous substances, poUutants, or

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contaminants as a principal element through treatment). If material exceeds TCLP it will be treated to reduce mobility. The waste material may be identified as a hazardous waste and is a source of contaminants. Based on current data, treatment ofthe waste material may be needed if identified as hazardous waste prior to on-site consolidation and capping.

This remedy will result in hazardous substances, pollutants, or contaminants remaining on-site in some areas above levels that do not allow unlimited use and unrestricted exposure. Therefore, five-year reviews and institutional controls will be required for this remedial action.

6. DATA CERTIFICATION CHECKLIST

The following information is included in the Decision" Summary section of this ROD. Additional infomiation can be found in the Administrative Record file for this Site.

Section(s)

1. How source materials constituting principal threats are addressed 18 2. Chemicals of Concem (COCs) and their respective concentrations 12 and 14 3. Current and reasonably anticipated fixture land use assumptions and current and

potential future beneficial uses of groundwater used in the baseline risk assessment and ROD .13

4. Baseline risk represented by the COCs 14 5. Cleanup levels established for COCs and the basis for these levels ...15 and 19 6. Potential land and groundwater use that will be available at the Site as a result

ofthe Selected Remedy 19 7. Estimated capital, annual operation and maintenance (O&M), and total present

worth costs, discount rate, and the number of years over which the remedy cost estiinates are projected ...: 16 and 19

8. Key factor(s) that led to selecting the remedy (i.e., describe how the Selected Remedy provides the best balance of tradeoffs with respect to the balancing and modifying criteria, highlighting criteria key to the decision) 20

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7. AUTHORIZING SIGNATURES

This ROD documents the Selected Remedy for soil, sediment, surface water, and waste material at the Tulsa Fuel & Manufacturing Superfund Site. This remedy is selected by EPA with concurrence from the Oklahoma Department of Environmental Quality.

U.S. Ermronmental Piwtection Agency

: jdmLiUPip^^ fldM D a t e : \ l m / ^ ^ ^ By

Samuel Coleman, P.E

Director

Superfund Division

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Record of Decision

Part 2: The Decision Summary

8. SITE NAME, LOCATION, AND BRIEF DESCRIPTION

The Tulsa Fuel & Manufacturing (TFM) Superfund Site is located in Collinsville, Oklahoma and is an abandoned zinc smelter and lead roaster that operated from 1914 through 1925. The approximately 61-acre Site is located one and one third miles south of downtown Collinsville, Oklahoma (Figure 1). The Site is bounded by "Old" U.S. Highway 169 and the Atchison Topeka Santa Fe railroad tracks to the east, a flooded strip mine pit (Strip Mine Pit) that comprises the boundary of a former coal mining operation to the south, and agricultural lots to the north and west. Additionally, property owned by the Faith Assembly Church bounds the Site to the north. The Collinsville Smelter, which is another former zinc smelter, is located approximately one fourth a mile to the east-northeast ofthe Site on 220 acres of property formerly owned by the Bartlesville Zinc Company.

The potentially responsible parties (PRPs) indentified for the Site did not participate in the RI/FS. Ongoing enforcement activities will continue and may result in an agreement for the cleanup ofthe Site. Otherwise, it is expected that EPA may fund ODEQ to lead the remediation at the Site while EPA enforcement efforts continue with respect to the recovery of cost expended by the govemment. The National Superfund Electronic Database Identification Number for the SiteisOKD987096195.

A more complete description ofthe Site can be found in the Remedial Investigation (RI) Report (Bums & McDonnell, 2007a).

9. SITE HISTORY AND ENFORCEMENT ACTIVITIES

1. History of Site Activities

The Tulsa Fuel and Manufacturing Superfund Site, located in Collinsville, Oklahoma is an abandoned zinc smelter and lead roaster that operated from 1914 through 1925. The Tulsa Fuel and Manufacturing smelting operation utilized nine fumaces, which were believed to be fueled by nearby natural gas wells. Other main stmctures ofthe smelter included a mechanical kiln-building, a condenser room, and a laboratory. A 2-million gallon capacity surface reservoir was

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used in conjunction with the condenser room during smelting operations. Large amounts of ore were stored on the Site in the area northeast ofthe waste piles. The Site was abandoned in the 1920s. The majority ofthe structures have been demolished, but several foundations and building footings remain. A residence, which was occupied from 1935 through Febraary 2002, was located on the Site near the former office building paymaster hut. The on-site residence was destroyed by a fire and is currently unoccupied. The residence has a water well that was used in the past for drinking water but is no longer in use. No other residential stractures are located on the site; however, a garage and a few storage sheds remain in place adjacent to the former residence. Waste material at the Site has affected soil, sediment, and surface water.

A more complete description ofthe Site can be found in the Remedial Investigation (RI) Report (Bums & McDonnell, 2007a).

2. History of Federal and State Investigations and Removal and Remedial Actions

Preliminary Assessment rOSDH. 1992) and Site Inspection (ODEQ. 1994) - The ODEQ conducted a Preliminary Assessment in November 1992 and a Site Inspection in September 1994. Based on the results, the metals arsenic, cadmium, lead, and zinc were found to be present in elevated amounts. ODEQ referred the property to the EPA for further action.

National Priorities List (NPL) - The Site was proposed to the NPL on September, 1998, and was fmalizedon January 19, 1999.

Removal Assessment (USEPA, 1999) - EPA subsequently conducted a Removal Assessment in 1999 to determine the absence/presence of hazardous materials, types and concentrations of hazardous substances, and estimate waste pile volumes.

Agency of Toxic Substances and Disease Registry (ATSDR. 2000) - ATSDR finalized the Public Health Assessment for the Site in July 2000.

Emergency Response - An emergency response action occurred in March 2004 to install a partial perimeter fence.

Cooperative Agreement - The EPA and ODEQ negotiated a Cooperative Agreement under which the ODEQ was the lead agency for the Remedial Investigation/Feasibility Study (RI/FS) with EPA acting as the supporting agency.

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Remedial Investigation/Feasibility Study (RI/FS) - From early 2005 through 2007, contractors for the ODEQ conducted a RI/FS. The RI, which was conducted in two phases, identified the types, quantities, and locations of contaminants and the FS developed options to address the contamination. The RI/FS information is described in more detail in the RI report (Bum & McDonnell, 2006 and 2007a) and the FS report (Bums & McDonnell, 2007b).

A more complete description ofthe Site can be found in the Remedial Investigation (RI) Report (Bums & McDonnell, 2007a).

3. History of CERCLA Enforcement Activities

Based on the investigation of Site historical information, one potentially responsible party (PRP) was identified. A Special Notice Letter, which notified the PRP of potential liability for Site response activity, was issued to the identified PRP in July 2000. The DEQ assumed the lead role for the RI/FS, and USEPA assumed the role pf support agency after the PFLP declined to conduct the RI/FS. •

10. COMMUNITY PARTICIPATION

Throughout the Site's history, the community has been interested and involved with Site activity. The ODEQ and EPA have kept the community and other interested parties updated on Site activities through informational meetings, fact sheets, and public meetings. Below is a brief summary of public outreach efforts:

Communitv Relations Plan: The ODEQ released a Community Relations Plan in October 2004 that outlined a program to address community concems and keep citizens informed about and involved in the remedial activities. This plan was updated in November 2007.

Public Meetings and Status Fact Sheets: The ODEQ and EPA have held several public meetings (July 1999, August 2005, October 2007, and July 2008) and mailed out fact sheets (April 2002, October 2007, and June 2008) to discuss Site activities related to the RI/FS and Proposed Plan.

Site Repository: The Collinsville Public Library, in Collinsville, OK, is used as the repository for Site information where the community is able to review documents and fact sheets related to the Site.

DEQ Website: A website was set up so that the public would be able to access Site

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progress and final reports as they became available. This website has been active throughout the investigative stages and through the comment period ofthe Proposed Plan. Documents are available through the following website: http://wvyw.deq.state.ok.us/lpdnew/SF/TulsaFuels.htm

• ODEQ Annual Reports/EPA monthly quarterly reports: These Site summaries were updated regularly to keep the public informed of Site issues and progress.

• Proposed Plan Fact Sheet and Public Meeting: The Proposed Plan was released on July 1 ̂ 2008. The formal Proposed Plan Public Meeting was held on July 24, 2008, and the comment period lasted from July 1, 2008, through July 30, 2008.

11. SCOPE AND ROLE OF RESPONSE ACTION

During the 2004 Emergency Response, the Site was secured with the installation of a partial perimeter fence. The Site will be addressed as one operable unit where the final remedial action will address Site contaminants and waste material that pose a current or future health risk. Risk reduction will be achieved through the following:

Consolidate and Cap Soil of Waste Material (On-site): Approximately 164,000 yd On-site Fixation or Stabilization and On-site Disposal of Sediment (On-site): Approximately 33,000 yd Excavation, Stabilization, and Disposal at TFM of Soil, Sediment, and Waste (Off-site): Approximately 1,600 yd^

12. SITE CHARACTERISTICS

1. Physical Site Character is t ics

The TFM Site is approximately one and one third miles south of downtown Collinsville in Tulsa County, Oklahoma (Figure 1) and is located in the NEl/4 SEl/4 NEl/4 of Section 31 and the SWl/4 NWl/4 of Section 32 in Township 22 North, Range 14 East. The regional climate is continental, with pronounced daily and seasonal temperature changes. Summers are hot and fairly humid, with an average high temperature inJuly and August above 90 °F. Winters are fairly short and mild; the average low temperature in January is 26 °F. Average annual rainfall is 42.4 inches, and May is the wettest month, with an average monthly rainfall of 6.1 inches. Severe storms and tomadoes occur primarily between the months of March and June (NWS, 2005). Tomadoes average just over one per year for Tulsa County (Oklahoma Climatological Society [OCS]," 2005). Snowfall is infrequent, with an average of approximately 9.2. inches per year, primarily occurring from December through March (NWS, 2005). Prevailing surface

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http://wvyw.deq.state.ok.us/lpdnew/SF/TulsaFuels.htm

winds are from the south with an average velocity of 10:7 mph (National Water and Climate Center [NWCC], 2005).

Collinsville is located in the North American Central Lowlands physiographic province. The terrain is characterized by nearly level uplands, bottomlands around the major streams, and gentle, rolling hills. The topography is generally flat with an average elevation of approximately 650 ft above mean sea level (msl) and a range in elevations from 620 to 740 feet above msl, within a one-mile radius ofthe Site. The Pennsylvanian-aged Seminole Formation, consisting of shale and sandstone interbedded with coal deposits, underlies the Site (Miser, 1954). The Seminole Formation is divided into upper sandstone, middle shale, and a basal sandstone. The middle shale zone locally contains the Dawson Coal, up to 30 inches thick, which was mined in the Collinsville area. Underlying the Seminole Formation is the Pennsylvanian-aged Holdenville Shale, composed of shale with minor sandstone and limestone strata (Tulsa Geological Survey [TGS], 1972); Based on information obtained during the RI field activities, bedrock was encountered beneath the Site at depths ranging from 7.2 to 12.5 ft below ground surface (bgs).

Overall surface drainage on-site is to the east, towards Blackjack Creek, a meandering stream located approximately one third of a mile from the Site boundaries. Blackjack Creek flows northerly for approximately five miles until it meets Horsepen Creek, which flows easterly for approximately two miles before meeting the Caney River (ODEQ, 1994). The Caney River is designated by the State of Oklahoma for the following uses: public and private water supply, warm water aquatic community, Class 1 irrigation, industrial and municipal process and cooling water, primary body contact recreation beneficial use, and aesthetics beneficial use (Oklahoma Administrative Code [OAC], 2004). The Site is located in a Federal Emergency Management Agency (FEMA) zone C area of minimal flooding (TGS, 1972).

The TFM Site comprises approximately 60.7 acres. A zinc and lead smelter was located at the site from 1914 to 1925. The majority ofthe stractures from smelter operations have been demolished; only a few foundations and building footings remain. All ofthe major features and media currently at the Site are shown in Figure 2 and 3 and include: an access road, slag roads, a waste area, a strip mine pit, five ponds, an unused residential well, a line of blackberry bushes, a small wetlands area, various vegetated areas, and one intermittent drainage area.

Smelter operation waste material consists of broken retorts and condensers, slag, building debris, ash, and bricks. The Access Road was constructed of smelter waste materials, and there are roads within the Site that are composed of slag. A Waste Area, covering approximately 25 acres, is comprised of discrete areas ofwaste materials ranging in thickness from approximately 0.5 ft to 7.0 ft. The Waste Area is located in the southern portion ofthe Site, extending northward from the Strip Mine Pit, a water filled pit that delineates the southem boundary ofthe Site. Portions ofthe Waste Area have sloughed off into the Strip Mine Pit. The remaining approximately 35 acres, of the Site, is known as the Non-Waste Area.

Site drainage and ran-off are uncontrolled. The Strip Mine Pit receives surface water nmoff from the Site. An intermittent stream, referred to as the Mid-Site Ravine, bisects the Site, flowing west to east, and discharges Site drainage into a low area along the eastem boundary referred to as the Eastem Wetlands. Surface water from the Strip Mine Pit also discharges to the

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Eastem Wetlands, which drain to the east through a culvert placed undemeath the railroad that runs parallel to the eastern border ofthe Site. Surface water exiting the Site flows to the north and east in an intermittent stream approximately three quarters of a mile before draining into Blackjack Creek. Three intermittent ponds. Ponds U 2 and 3, which are thought to be remnants ofthe 2-million gallon reservoir, are located north ofthe former smelter operations area in the 25-acre Waste Area. In addition, two smaller ephemeral ponds, Ponds 4 and 5 are located at the site in vegetated areas. There is evidence of hunting and fishing activity around the ponds and the Strip Mine Pit.

There is no major bedrock or alluvial aquifer beneath the Site. The Pennsylvanian-aged Seminole Formation, designated as a Class IIB minor use general basin, comprises the upper bedrock aquifer beneath the Site. Activities from the RI indicate that groundwater is located ubiquitously at the Site; however, the Seminole Formation yields only small amounts of fair to poor quality water (OAC, 2004). The Seminole Formation has a thickness of approximately 200 feet and consists of shale, sandstone, and thin coal beds. There are no municipal or other public water wells or Wellhead Protection Areas within a four-mile radius ofthe Site; however, several private wells are located within a one-mile radius including one from a residence which was located on site from 1935 until 2002 when it was destroyed, by a fire (Bums & McDonnell 2007a). The identified wells vary in depth from 32 ft to 200 ft bgs and exhibit yields ranging from 1 to 40 gallons per minute (gpm). Water levels obtained from seven new monitoring wells indicate that groundwater flow is toward the south/southeast.

The Site is underlain by relatively thin, unconsolidated overburden, comprised primarily ofthe Kanima Series, the Okemah-Parson-Carytown complex, and the Dennis-Radley complex (United States Department of Agriculture [USDA], 1977). This overburden consists of silt, clay, silty loam, and shale sediments and residuum. Bedrock, consisting primarily of shale with a few instances of sandstone and limestone, was encountered beneath the Site at depths ranging from 7.2 to 12.5 ft bgs.

The Site includes large areas vegetated by various grass species, trees, and shrabs, creating diverse habitat types. There are areas of dense vegetation interspersed with sparsely vegetated areas and patches of bare or rocky ground. A line of blackberry bushes approximately 1400 feet long from which people have been observed harvesting berries is located along the eastem boundary ofthe site. According to the U.S. Fish and Wildlife Service and Oklahoma Biological Survey records, four state and federally protected wildlife species are known or are likely to occur in Tulsa County.

2. Site Con tamina t ion

The RI field investigation activities were conducted in two phases: Phase 1 was conducted from July 11 through October 4, 2005, and Phase 2 was conducted from August 14 through September 21, 2005. The sampling strategy was designed to provide a basis for risk assessment ofthe Site through characterization of potential source areas and evaluation ofthe nature and extent of contamination. Sampling activities were conducted for on-site surface and subsurface soils and waste, off-site surface soils, surface water, sediment, groundwater, vegetation, and air. These media were analyzed for contaminants of potential concem (COPCs) including arsenic.

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cadmium, lead, and zinc. To provide for a comparison of Site conditions to background levels, samples for each ofthe matrices were collected from off-site and/or up stream locations. Conceptual Site Models (CSM) were developed to characterize the potential releases of contaminants from primary sources of hazardous substances to secondary and tertiary sources, to determine exposure media and subsequent routes of exposure, and to define how the contamination might affect potential human receptors (Figure 4) and Site ecosystems (Figure 5).

On-site surface soil, subsurface soil, and waste sampling resulted in the collection of 221 soil/waste samples from 63 boring and 21 trench locations. Off-site surface soil sampling resulted in the collection of 184 surface soil samples from 50 distinct properties. Surface water and sediment samples were collected from six on-site features and five off-site features. Groundwater samples were collected from nine temporary piezometers, seven newly installed monitoring wells, and one existing residential well, during three separate sampling events. Berry, leaf, and/or root samples were collected from blackberry bushes on-site and on the adjacent property in the 2004, 2005, and 2006 growing seasons. Two air samples were collected to evaluate air quality conditions at the Site.

The primary source material comprising the principal and low level threat waste consists of smelter operations debris, including broken retorts, condensers, ash, and slag. Review ofthe Site indicated a clear division into two areas: those where waste materials were visually observed during sampling and those areas where waste materials were not visually observed during sampling.

A generalized diagram illustrating the various media present at the Site and potential routes of contaminant transport are shown in Figure 3. Although overland flow to surface water and sediment is likely at the Site, it does not appear that any of these pathways are major contaminant transport routes. Most ofthe contaminants were detected in surface and subsurface soils, indicating that leaching from surface soils is a possible contaminant transport mechanism at the Site. Although metals were detected in the soils, little migration of these Contaminants to groundwater appears to be occurring; the constituents appear to be remaining in the soil. Smelter waste materials were visually observed at the ground surface or within trenches or soil borings in the 25-acre Waste Area. The entire Waste Area, which includes the Access Road, contains soil with lead elevations in the 0 to 0.5 ft bgs interval. Maximum concentrations in the Waste Area were: 1,170 mg/kg arsenic, 1,620 mg/kg cadmium, 71,700 mg/kg lead, and 165,000 mg/kg zinc. Horizontally, the highest concentrations of metals were observed in the south portion ofthe site and were associated with the former smelter operations area. The southem extent ofthe Waste Area was defined at the Strip Mine Pit, into which waste slag piles were observed to have collapsed. Soil samples collected off-site south ofthe Strip Mine Pit did not

. exhibit elevated metals results. On the eastem edge ofthe Waste Area, waste materials were located outside of the fence in a low area between the Site boundary and the Atchison Topeka Santa Fe Railroad right-of-way. The railroad, constracted in 1899 prior to. operation of the smelter, has acted as a natural physical barrier to retain waste materials to the west side ofthe railroad tracks. The westem and northem edges ofthe Waste Area are adjacent to the Non-Waste Area of the Site.

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The vertical extent of metals contamination varies across the Waste Area. Waste materials vary in thickness from two to three feet below ground surface (bgs) across much ofthe Waste Area. On the west side of Pond 3, waste was generally encountered to approximately one foot bgs. In the area between Ponds 1 and 2 and between Ponds 2 and 3, waste was detected at up to five feet bgs. Across the length ofthe former smelter operations area, waste materials were observed up to seven feet bgs. Samples collected from areas and depth intervals where waste material was observed exhibited results for toxicity characteristic leaching procedure (TCLP) cadmium or TCLP lead that exceeded the toxicity characteristic maximum concentration. Due to the TCLP failure, soil and waste materials at these locations would be classified as hazardous.

Metals concentrations decrease with increasing depth. Samples collected below the waste materials from native clay material had very few metal elevations. In many cases these results were similar to background concentrations. The samples collected from native materials beneath the waste exhibited soil results that did not fail the TCLP screening criteria. Twenty five (25) acres ofthe 36 acre Contamination in the Non-Waste Area exhibited soil concentrations wifh elevated metals in the 0 to 0.5 ft bgs interval. Small areas nearest the Waste Area and Access Road exhibited lead results in excess of residential screening levels up to two feet bgs. Maximum concentrations in this area were: 416 mg/kg arsenic, 799 mg/kg cadmium, 5,170 ing/kg lead, and 41,400 mg/kg zinc. Concentrations of metals in soil samples collected nearest the northem and eastem Site boundaries in the Non-Waste Area exhibited the lowest on-site metal concentrations. SoiL samples collected from properties directly west ofthe Site exhibited elevated concentrations of lead and defined the westem extent of contamination. The horizontal extent of metals in the soils Non-Waste Area was less clearly defined along the westem boundary.

Surface soil samples were collected from off-site locations to determine the presence and extent of contamination due to potential aerial distribution of metals from the TFM smokestack and historical placement ofwaste materials. Samples were also collected from targeted sampling areas such as parks, schools, and playgrounds; tribal member properties near the Site; and areas where waste materials were either visually observed or historically reported. Samples were collected from properties in the area immediately surrounding the Site and from up to one and one half miles away. The data do not suggest an aerial dispersion plume from the TFM; properties located further than one mile from the Site exhibited the lowest concentrations of metals in surface soil. At several properties immediately adjacent to the Site and typically where smelter waste materials were visually observed, metals exhibited elevated results.;

Surface water and sediment were characterized for the five on-site ponds, the Mid-Site Ravine, and the Strip Mine Pit immediately adjacent to the Waste Area. The highest concentrations of metals were noted in surface water and sediment associated with Ponds 1 through 3 and the Mid-Site Ravine. Waste materials were observed in and around these surface water bodies, and a retort embankment was observed at Pond 3.

Surface water and sediment were characterized for off-site areas where surficial transport from the Site could have occurred, including the drainage ditches associated with the railroad and Old US Hwy 169, a drainage on the northem portion of Tulsa County Plat 34010 in Sec. 32 T22N RME, and a drainage on the southem portion of Tulsa County Plat 34010 in Sec. 32 T22N

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RME. The ditches adjacent to the railroad and Old US Hwy 169 and the northem drainage on Tulsa County Plat 34010 in Sec 32 T22N RME exhibited elevated metals concentrations in surface water and sediment. A large culvert passes from the Site under the railroad and to these drainages. Concentrations of metals decreased with increasing distance from the culvert.

Limited impacts were noted in the shallow groundwater beneath the Site in one well during the Phase 1 investigation. During Phase 2 a deeper well was installed to define the vertical extent of metals in the groundwater. Analytical results determined that Site contaminants were not present in deeper groundwater. An off-site well was installed down gradient, and a determination was made that Site contaminants were not being transported off-site via gi:oundwater.

Samples from off-site and on-site blackberry bushes collected during the 2004, 2005, and 2006 growing seasons indicate elevated concentrations of metals in on-site bushes relative to off-site bushes. Since washing ofthe berries reduced metals concentrations, the berry contamination appeared to be a result of dust from the soil onto the berries rather than plant uptake.

The results ofthe air monitoring samples collected upwind versus downwind were similar, suggesting that the TFM is not currently a source of airbome contamination to off-site locations.

At the TFM site, three contaminants are identified as Chemicals of Concem (COC): arsenic, cadmium, and lead. Arsenic is a naturally occurring element whose compounds are, commonly used as pesticides and for wood preservation. Arsenic is a COC for on-site and off-site soil arid sediment. The detected concentrations for arsenic ranged from non-detect to 1,170 mg/kg for on-site soil and from non-detect to 588 mg/kg for on-site sediment. Off-site, the detected concentrations of arsenic in soil ranged from non-detect to 538 mg/kg, and from non-detect to 341 mg/kg for sediment. Cadmium is a naturally occurring element whose compounds are used in the production of batteries, plastics, and metal coatings. Cadmium is a COC for on-site and off-site soil, sediment, and surface water. The detected concentrations for cadmium ranged from non-detect to 1,620 mg/kg for on-site soil, from non-detect to 1,400 mg/kg for on-site sediment, and from non-detect to 184 jxg/L for on-site surface water. Off-site, the detected concentrations of cadmium in soil ranged from non-detect to 193 mg/kg, from non-detect to 987 mg/kg for sediment, and from non-detect to 810 fxg/L for surface water. Lead is a naturally occurring element with many different uses, including the production of batteries, ammunition, and metal products. Lead is a COC for the soil and sediment on- and off-site. The detected concentrations for lead ranged from non-detect to 71,700 mg/kg for on-site soil and from 180 mg/kg to 8,150 mg/kg for on-site sediment. Off-site, the detected concentrations of lead in soil ranged from non-detect to 15,900 mg/kg and from 119 mg/kg to 5,080 mg/kg for sediment.

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13. CUimENT AND POTENTIAL FUTURE SITE AND RESOURCE USES

( •

1. C u r r e n t and F u t u r e L a n d Uses

The land occupied by the TFM Site is currently unused and vacant but due to residential interest in the area, it is reasonable that future land use for the site may be zoned as residential.

2. C u r r e n t and F u t u r e G r o u n d w a t e r Uses

There is no major bedrock or alluvial aquifer beneath the Site. The Pennsylvanian-aged Seminole Formation, designated as a Class IIB minor use general basin, comprises the upper bedrock aquifer beneath the Site. Activities from the RI indicate that groundwater is located ubiquitously at the Site; however, the Seminole Formation yields only small amounts of fair to poor quality water (OAC, 2004). The Seminole Formation has a thickness of approximately 200 ft. and consists of shale, sandstone, and thin coal beds. There are no municipal or other public water wells or Wellhead Protection Areas within a 4-mile radius ofthe Site; however, several private wells are located within a one-mile radius including one frdrii a residence which was located on site from 1935 until 2002 when it was destroyed by a fire (Bums & McDonnell, 2007a). The identified wells vary in depth from 32 ft to 200 feet bgs and exhibit yields ranging from 1 to 40 gallons per minute (gpm). Water levels obtained from seven new monitoring wells indicate that groundwater flow is toward the south/southeast.

3. Current and Future Surface Water Uses

Surface water drains from the Site to the east, towards Blackjack Creek located approximately one third of a mile from the Site boundaries. Blackjack Creek flows northerly for approximately five miles until it meets Horsepen Creek, which flows easterly for approximately two miles before meeting the Caney River (ODEQ, 1994). The Caney River is designated by the State of Oklahoma for the following uses: public and private water supply, warm water aquatic community. Class I irrigation, industrial and municipal process and cooling water, primary body contact recreation beneficial use, and aesthetics beneficial use (OAC, 2004). There is evidence of fishing and hunting activity around the intermittent ponds on the TFM. Surface water is limited to the Strip Mine Pit, the Mid-site Ravine, and minor drainage areas/ditches.

14. SUMMARY OF SITE RISKS

As part ofthe RI, a baseline human health risk assessment (BHHRA) and an ecological risk assessment were completed in August 2007. The assessments estimate the probability and magnitude of potential adverse human health and environmental effects from exposure to contaminants at the Site assuming no cleanup occurred. These assessments identify contaminants and exposure pathways and provide the basis for taking action at the Site.

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The risk discussion does not summarize the entire baseline risk assessment, but focuses on those receptors, pathways, and contaminants that are driving the need for the cleanup action described in this ROD. For this Site, cleaning up to a residential scenario will be protective of future residents, trespassers, industrial and commercial workers, and ecological receptors. The CSMs presented in support the risk discussion and can be referenced throughout the risk section (Figures 4 and 5). The complete human health and ecological risk assessments are included in the RI Report (Bums & McDonnell, 2007a).

Human Health Risk Assessment

The purpose of this assessment is to evaluate baseline potential risks that might be experienced by human receptors such as on-site and off-site residential, industrial, and recreational populations coming into contact with contaminated soil, air, groundwater, surface water, sediment, fish tissue, and/or plant tissue contamination associated with the Site. It was assumed that people could be exposed to site-related contaminants through direct contact, accidental ingestion, ingestion of blackberries or fish, and inhalation. The populations characterized for the risk assessment included adult and child residents, trespassers, outdoor commercial/industrial workers, constraction/utility workers, and recreationists.

Due to the presence ofwaste piles in the southem half of the Site, the on-site portion of this risk assessment is subdivided into the Waste and Non-Waste Areas ofthe Site for the risk evaluation. The off-site portion of this risk assessment is subdivided into the individual properties that were sampled during the RI.

a. Identification of Chemicals of Concern

The chemicals of concern (COC) for the site are arsenic, cadmium, and lead. Arsenic is a COC for on-site and off-site the soil and sediment. Cadmium is a COC for on-site and off-site soil, sediment, and surface water. Lead is a COC for on-site and off-site soil and sediment. Table 1 presents the exposure point concentration (EPC: i.e., the concentration that will be used to estimate the exposure and risk from each COG in soil, sediment, and surface water), the range of concentrations detected for each COC, the frequency of detection (i.e., the number of times the chemical was detected in the samples collected at the Site), and how the EPC was derived.

b. Exposure Assessment

flhe objectives ofthe exposure assessment are to characterize potentially exposed human populations in the areas associated with the Site, to identify actual or potential exposure pathways, and to determine the extent of exposure. Exposure refers to the potential contact ofan individual (the receptor) with a contaminant.

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As part ofthe exposure assessment, a CSM (Figure 4) showing the potential human pathways at the Site was developed based on local land use pattems associated with the Site. Currently, the Site is vacant, and no firm development plans are in place. Due to the proximity ofthe Site to residential areas it is possible that development could be residential. Populations reasonably expected to be present at the Site are: adult and child residents, youth trespassers, outdoor commercial/industrial workers, and construction/utility workers. Populations reasonably expected to be present at off-site locations are: adult and child residents, and youth trespassers. Exposed populations must then either ingest, inhale, or dermally absorb COCs to complete an exposure pathway and possibly experience a health risk. The potentially completed exposure pathways for waste, non-waste on-site and off-site areas quantified in the risk assessment are listed in the RI (Bum & McDonnell 2007a). Exposure equations and parameters are presented in Tables 2 through 7.

c. Toxicity Assessment

The toxicity assessment is accomplished in two steps: hazard identification and dose-response assessment; Hazard identification is the process of determining whether exposure to a chemical is associated with a particular adverse health effect. The dose-response assessment is the process of predicting a relationship between the dose received and the incidence of adverse health effects in the exposed population. From this quantitative dose-response relationship, toxicity values are derived that can be used to estimate the potential for adverse effects as a function of potential human exposure to the chemical.

Chemicals are generally categorized into two groups based on the types of effects they have on human health: carcinogens and non-carcinogens. For risk assessment purposes, chemicals placed in the carcinogenic category are limited to those that have been shown to be carcinogenic in animals and/or humans. Excessive exposure to all substances, carcinogens and non-carcinogens, can produce adverse non-carcinogenic effects; therefore, reference doses are identified for COCs regardless of their classification, and cancer slope factors are identified for those COCs that are classified as carcinogenic. Tables 8 through 11 summarize the cancer and non-cancer toxicity data for the Site COCs. - '

Lead represents a special situation with regard to both its cancer and non-cancer toxicities. Populations especially sensitive to lead include children and pregnant women. The toxic effects of lead involve several organ systems including the nervous, vascular, and renal systems with the critical, or most sensitive, effects involving the nervous system. In children, lead exposure has been shown to decrease intelligence (IQ) scores, slow growth, and cause hearing problems. Exposure of a pregnant woman to lead may cause premature birth, lower birth weight, and decreased mental ability in the infant. Lead is categorized as a probable human carcinogen, but also produces neuropathic effects that do not appear to have a threshold. Therefore, any exposure to lead may have an associated risk. Human toxicity has been historically evaluated in terms of blood lead levels rather than exposure levels.

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d. Risk Characterization

The risk characterization is an evaluation of the nature and degree of potential carcinogenic and non-carcinogenic health risks posed to current and future receptors at the Site. Human health risks for carcinogenic and non-carcinogenic effects are discussed in dependently because ofthe different toxicological endpoints, relevant exposure durations, and methods employed in characterizing risk. The potential for carcinogenic effects is limited to exposure to only those chemicals classified as carcinogens, while both carcinogenic and non-carcinogenic chemicals are evaluated for potential non-carcinogenic effects. Carcinogenic and non-carcinogenic risks were evaluated for each exposure pathway and scenario by integrating the exposure doses calculated in the exposure assessment with the toxicity criteria for the COCs determined in the toxicity assessment.

Carcinogenic Risk

For carcinogens, risks are expressed in terms of lifetime excess cancer risk. This concept assumes that the risk of cancer from a given chemical is in "excess" of the background risk of developing cancer. The background risk of developing cancer is approximately 1 in 3 chances during a lifetime according to the American Cancer Society. For example, a risk of lE-04 or 1 x 10"̂ equates to approximately one excess cancer case in a population of 10,000 individuals due to exposure to the cancer-causing substance over a 70-year lifetime, and a risk of 1 E-06 or 1 x 10"̂ equatesto approximately one excess cancer case in a population of 1,000,000 individuals due to exposure to the cancer-causing substance over a 70-year lifetime. The excess lifetime cancer risk is calculated using the following equation:

Lifetime Excess Carcinogenic Risk = LADD x CSF /

Where:

LADD = Lifetime average daily intake (dose) ofthe carcinogen, averaged over a

70-year lifetime (mg/kg-day).

CSF = Chemical- and route-specific cancer slope factor (mg/kg-day)"^

The carcinogenic COC for the Site is arsenic. The USEPA's target risk range for total excess lifetime cancer risk is 1 in 10,000 to one in a million. The total excess lifetime cancer risks for the populations that exceeded that range were:

• Future Adult and Child Residents - On-Site Waste and Non-Waste Areas • Future Outdoor Commercial/Industrial Worker - On-Site Waste Area

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Current Child and Adult Resident at Various Off-Site Residences

Tables 12A through 12V show the results for carcinogenic risks for the above populations.

Non-carcinogenic Risks

Non-carcinogenic health effects can range from rashes, eye irritation, and breathing difficulties to organ damage, birth defects, and death. Non-carcinogenic health effects are evaluated by comparing the estimated daily intake ofthe COC, which is averaged over the period of exposure, to its reference dose (RfD). The RfD represents the daily intake of a chemical to which a receptor can be exposed over a given length of time without any reasonable expectation of adverse non-carcinogenic health effects. This is accomplished by the calculation of hazard quotients (HQs) and hazard indices (His). The HQ for a particular COC is the ratio ofthe estimated daily intake through a given exposure route and the applicable RfD. The HQs, determined for each COC by exposure pathway and age group, are summed within an exposure scenario to obtain a HI. The HI is an expression of additivity of non-carcinogenic health effects. A HQ>1 or HI>1 indicates the potential for non-carcinogenic health effects occurring under the defined exposure conditions. A HQ < 1 or HI < 1 indicates that it is unlikely for adverse non-carcinogenic health effects.

The HQ is calculated as follows:

HQ = ADD/RfD

Where:

ADD = Chronic average daily dose for the chemical averaged over the

appropriate exposure period (mg/kg-day).

RfD = Chemical- and route-specific reference dose (mg/kg-day) for a similar exposure period.

The key concept here is that a "threshold level" exists below which non-cancer health effects are no longer predicted. The USEPA level of concem for non-cancer risk is a hazard index greater than one. The following populations had a calculated non-cancer hazard index greater than one:

• Future Adult and Child Residents - On-Site Waste and Non-Waste Areas • Future Outdoor Commercial/Industrial Worker - On-Site Waste Area • Future Constmction/Utility Worker - On-Site Waste Area • Future Trespasser - On-Site Waste Area

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• Current and Future Off-Site Trespasser • Current Child Resident at Various Off-Site Residences • Current Adult and Child Residents at Various Off-Site Residences

Tables 12A through 12V show the results for non-carcinogenic risks for the above populations.

Lead Risks

Risk from exposure to lead is evaluated by modeling the potential level of lead that could occur in blood. Since children are the most sensitive to lead impacts, residential exposures are focused on children. Similarly, commercial/industrial exposures are focused on the fetuses of pregnant adult workers. Modeling results that show a greater than 5 percent chance of a blood lead concentration greater than 10 micrograms of lead per deciliter of blood are considered unacceptable. The predicted blood lead levels for the site were unacceptable in the following populations:

• Future Adult and Child Residents - On-Site Waste and Non-Waste Areas • Future Outdoor Commercial/Industrial Worker - On-Site Waste Area • Future Constraction/Utility Worker - On-Site Waste and Non-Waste Area • Current Child and Adult Resident at Various Off-Site Residences

Tables 13 A through 13F show the results for lead risks for the above populations.

e. Uncertainty

Some level of uncertainty is introduced into the risk characterization process every time an assumption is made. In regulatory risk assessment, the methodology dictates that assumptions error on the side of overestimating potential exposure and risk. The use of numerous . assumptions may overestimate potential exposure and exaggerate estimates of potential risk.

Table 14 summarizes the primary uncertainties associated with the Site risk assessment. Refer to the RI for a more detailed description ofthe uncertainty analysis (Bums & McDonnell, 2007a).

2. Ecological Risk Assessment

The following paragraphs provide an overview ofthe ecological risk assessment and its findings. A majority ofthe areas posing ecological risk are co-located with areas posing human health risk (see Section 15 of this ROD). Therefore, risk tables for ecological receptors are not included in this ROD.

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The primary objective ofthe ecological risk assessment is to address whether concentrations of COCs at the Site are likely to cause adverse effects to the ecological receptors. The Site was evaluated for the presence of ecological receptors (plants and animals) and completed ecological exposure pathways to contaminants in surface and subsurface soil, surface water, sediment, and plant and fish tissue. Potentially completed exposure pathways identified at the Site included direct contact or ingestion of surface soils by plants and wildlife, direct contact or ingestion of surface water by plants and wildlife, and direct contact or ingestion of surface water sediments by wildlife. Additionally, area fish and wildlife could be exposed through bioaccumulation of Site related constituents in benthic invertebrates, aquatic and terrestrial invertebrates, aquatic and terrestrial plants, small mammal prey, and fish.

Eighteen indicator species were selected to model and evaluate potential risk. Figure 5 is the Ecological Conceptual Site Models. These species were not always identified at the Site but habitat at the Site is suitable for these species. Analysis ofthe potentially completed exposure pathways from the Site shows that metals (arsenic, cadmium, lead, and zinc) present the greatest potential risk to plant and wildlife species. Ofthe terrestrial receptor species chosen for evaluation, the short-tailed shrew and the American Robin had the highest amounts of risk. Of the species that would have regular contact with surface water and sediment, the mallard and the great blue heron had the highest amount of risk. The areas and media resulting in unacceptable levels of ecological risk were analogous to areas and media with unacceptable human health risk. Since addressing human health risk will also address those areas posing ecological risk, the remainder of this Record of Decision discusses Site cleanup in terms ofthe human health.

3. Basis for Response Action

The response action selected in this ROD is necessary to protect the public health or welfare or the environment from actual or threatened releases of hazardous substances into the environment which may present an imminent and substantial endangerment to public health or welfare or the environment. The human health risk assessment showed an excess lifetime cancer risk range greater than 1 in 10,000 to one in a million and non-carcinogenic HI>1 for various risk scenarios. Additionally, a majority ofthe areas posing ecological risk are co-located wdth areas posing human health risk.

15. REMEDIAL ACTION OBJECTIVES

Remedial Action Objectives (RAOs) are the cleanup objectives for protection of human health and the environment. RAOs were developed for Site soil, sediment, surface water, and waste material. Areas of Concem (AOCs) are areas on the Site that require remediation based upon the RAOs and cleanup levels. The AOCs for the Site are shown in Figures 6 and 7. This section provides the basis for evaluating the cleanup options presented in Section 16. The RAOs for the Site are listed below.

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Soil and Waste Materials -

• Protect human health by preventing direct contact, through the ingestion and inhalation exposure pathways with arsenic, cadmium, and lead contaminated on-site and off-site soil and waste material by reducing arsenic, cadmium, and lead concentrations to residential levels less than 37 ppm, 75 ppm, and 500 ppm, or to nonresidential levels less than 200 .ppm, 560 ppm, and 1,000 ppm respectively.

Sediment

• Protect human health and the environment by preventing direct contact, through the ingestion pathway, with arsenic, cadmium, and lead contaminated sediment by reducing arsenic, cadmium, and lead concentrations to levels less than 181 ppm, 813 ppm, and 500 ppm, respectively. '

Surface Water

• Protect human health and the environment by preventing direct contact, through the ingestion pathway, with cadmium contaminated surface water by reducing cadmium concentrations to levels less than 238 ppb.

1. Cleanup Levels

The land occupied by the TFM Site is currently unused vacant but due to development interest in the area it is reasonable that future land use for the site may be zoned as residential. Cleanup to a residential scenario will result in partial unlimited use, unrestricted exposure, and will be protective for all other human and terrestrial ecological receptors. Therefore, in order to be protective for Site reuse under a residential scenario and meet the RAOs, cleanup levels were established. Site-specific cleanup levels are the desired endpoint concentrations for each exposure route that are believed to provide adequate protection of human health and the environment. Cleanup levels for both resideritial and non-residential soil were established. The cleanup levels for the Site are presented in Table 15. In addition to the established cleanup levels for the Site a visual standard for waste removal will be applied. Visible waste associated with the historical smelter operation will be addressed during the Remedial Action for the Site. In the absence of Federal or State cleanup standards for soil contamination, th'e Site cleanup levels are based on the baseline risk assessments and Oklahoma-specific, smelter-specific bioavailability data (ODEQ, 2008a). The smetter-specific bioavailability data originates from a similar smelter site known as the National Zinc Corporation Site (NZS) smelter located in Bartlesville, Oklahoma.

The use of data generated from the NZS studies is appropriate for the TFM smelter and other smelter sites in Oklahoma because they are all of similar design and used similar processes and ores. The TFM smelter used nearly identical ores as were used at the NZS, and processed these ores through a nearly identical process, the waste materials at these two sites (i.e., ore concentrate, smelter emissions, and solid waste materials) should be identical. Additionally,

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similar soil types are present.at both NZS and TFM resulting in similar weathering of released materials. An important difference between NZS and TFM is their different periods of operation. NZS operated approximately sixty-nine years while TFM operated approximately eleven years. This would decrease the amount of material entering the environment due to the smelter. Although the smelters' time of operation is different the NZS information is specific to Oklahoma and more detailed than EPA literature values.

The following variables and assumptions were taken from the NZS Risk Assessment and Bioavailability Study (PTI, 1994).

• The fraction ingested from a contaminated source for arsenic was revised to 0.25, while cadmium was revised to 0.33

• The target risk level for all cancer scenarios was revised to three in one-hundred thousand (i.e., 3E-05)

• The assumed indoor house dust concentration in the USEPA's lEUBK Model was calculated using the equation in Section 7.1.1.2 in PTI, 1994

• The soil lead bioavailability was revised to twenty percent

The values for fraction ingested from a contaminated source for arsenic and cadmium were based on studies at the Bartlesville smelter site to evaluate the percent of arsenic and cadmium that is bioavailable. These studies indicated that only 25 percent of arsenic and 33 percent of cadmium in soil is absorbed through the digestive tract. Incorporating this bioavailability data into the PRG calculations resulted in using values for fraction ingested from a contaminated source of 0.25 and 0.33 for arsenic and cadmium, respectively.

In addition, some averaging times and exposure frequencies for non-cancer and cancer risks that were used in the TFM RJ's BHHRA and FS deviated from EPA guidance (Bums & McDonnell 2007a, b). The seasonality ofthe climate in Collinsville, Oklahoma tends to preclude year-round outdoor work. The outdoor commercial/industrial worker was assumed to be engaged in seasonal grounds keeping and landscaping activities, which are likely to take place from mid-April through mid-October. Therefore, the exposure frequency was assumed to equal 125 days per year, representing half of a working year. Grounds keeping activities around the ponds were assumed to take place weekly during the 6-month working season (i.e., exposure time of 26 days per year). Because ofthe size ofthe Site and the significant level of construction required to develop the Site further for either commercial/industrial or residential purposes, the constmction/utility work was assumed to occur for 6 months (130 working days). Similarly to residents, youth trespassers are likely to visit the Site only during the five warm months of the year. However, given that, children aged 9-15 generally have more free time during the summer months then adults typically have, it was conservatively assumed that youth trespassers would spend 3-4 days per week for five months, or 72 days per year on the Site.

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These decisions are consistent with Final Remedial Goals established at other smelter sites in Oklahoma and are based on the site-specific information from the TFM site and the Risk Assessment and Bioavailability Study at the NZS.

The TFM site has two areas where the development of ecological PRGs may have applied. The first area consists of four on-site ponds. The ponds are remnants ofthe two million gallon reservoir that was once part ofthe site. Smelter waste was used in constmction ofthe reservoir and is still present in the ponds. The second area is the abandoned Strip Mine Pit that forms the southem boundary of the property. The Strip Mine Pit is a result of a coal mining operation that was not part of the smelter operations.

The TFM RI Report showed that sediments and surface water in the on-site ponds contained elevated metals and noted the presence of smelter waste as a constraction material. In contrast, the Strip Mine Pit shows low levels of metals in the sediment and none in the surface water. The report notes that smelter wastes have sloughed' into the pit. The Strip Mine Pit has an active ecological system while the ponds have a limited ecological system (Bums & McDonnell, 2007a).

An EPA Removal Assessment performed in 1999 collected fish tissue samples from the Strip Mine Pit. None ofthe metals of concem were detected in the fish tissue from the Strip Mine Pit. The presence of a healthy fish population in the Strip Mine Pit and the data from the tissue sampling indicate that the metals that are present in the pit sediment are not accumulating in fish tissue (USEPA, 1999). No fish were observed in the onsite ponds during the sampling event.

It was determined that ecological PRGs were not needed for this site. The sediment in the onsite ponds will require remediation based on human health PRGs, and the smelter waste that was used in constraction will also be removed. The Strip Mine Pit poses no apparent ecological hazards. Waste and sediment from the pit may be removed based on human health PRGs. Since the metals of concem at the TFM site are co-located across the site, remediation ofthe sediment to human health PRGs will further reduce risks to the ecological environment.

16. DESCRIPTION OF ALTERNATIVES

The Feasibility Study identifies potential technologies representing a variety clean up options for use at the Site. Several altematives were assembled and then screened out after being evaluated for effectiveness, implementability, and cost relative to Site conditions (Table 16 and 17). The altematives are discussed below.

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1. C o m m o n Element of Remedia l Alternat ives Except Al ternat ive 1 -No Action a n d - Stabilization and Off-Site Disposal a t a R C R A Permi t t ed Facility

The following paragraph identifies the common element ofthe alternatives except for Remedial Altemative 1 - No Action and - Stabilization and Off-Site Disposal at a RCRA Permitted Facility. The Common Element will achieve applicable RAOs. This element may be compatible with residential land use.

The ODEQ will file a recordable notice of remediation taken pursuant to CERCLA in the land records ofthe county in which the site is located. This notice will contain a legal description of the affected property and will identify all engineering controls used to ensure the effectiveness of the remediation. Additionally, the notice will contain a prohibition against engaging in any activities that could cause damage to the remedial action or the engineering controls or that could cause recontamination ofthe soil or groundwater. The notice will contain appropriate restrictions on land use or other activities that are incompatible with the cleanup levels, including but not limited to restrictions against using groundwater for drinking or irrigation purposes or redeveloping the land for residential use in some areas. The ODEQ has authority to take administrative or civil action to recover costs from or to compel compliance with this notice against any person who damages or interferes with the remediation, engineering controls or continuing operation, maintenance or monitoring of the site.

2. Summary of Remedial Alternatives

The TFM Remedial altematives selected and cost are presented in Tables 18A through 18G and discussed in the following paragraphs. The cost associated with on-site sediment is included with the cost for on-site soil and waste altematives. The cost associated with off-site sediment is included in the cost for off-site soil altematives. The alternatives are numbered to correspond with the numbers in the FS Report (Bums & McDonnell, 2007b). The technologies comprising the altematives were evaluated for practicality, as indicated by effectiveness and implementability, as well as cost. Technologies that were not practical or cost effective were removed from further consideration. The remaining technologies were then reviewed to identify combinations that would address all aspects of each Area of Concern's (AOC) contamination (Figures 6 and 7). These combinations are referred to as remedial altematives.

a. Alternative 1 - No Action

Regulations goveming the Superfund program generally require that the "no action" altemative be evaluated to establish a baseline for comparison. Under this altemative, the ODEQ and EPA would take no action at the Site or at off-site properties to prevent exposure to the soil, sediment, and other site-related contamination. All remedial altematives, except the "no action" altemative, are expected to attain the RAOs and meet appropriate waste disposal regulations. Selection ofthe "no action" altemative would mean that the RAO's would not be met and

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possible exposure of COCs could occur to current and future human receptors and ecological receptors. Altemative 1 - No Action associated costs are:

• Estimated Capital Cost - $0 • Estimated Annual O&M Cost - $0 • Estimated Constraction Timeframe - None

By leaving the impacted soil and waste materials in place, a formal review ofthe Site will be required every five years. Conducting remedy jeviews is assumed to include monitoring of all media and wastes remaining on the Site. Costs associated with this "no action" altemative include conducting five-year reviews with associated groimdwater monitoring and a Site Closure Report.

b. On ^Site Soil and Waste Materials Areas

Altemative 2 - Consolidation and Cap is EPA and ODEQ's selected remedial altemative for on-site soil and waste material areas. Altemative 2 associated costs are:

Estimated Capital Cost - $5,787,934 Estimated O&M Cost (30 yr) - $431,132 Estimated Groundwater Well - $55,200 Estimated Construction Timeframe - 20 weeks Estimated Time to Achieve RAOs - 20 weeks

For this altemative approximately 164,000 yd̂ of soil and waste materials on the Site would be capped. Several consolidation and capping options were evaluated and the specific design such as size, type, depth of cap, liner, and cost of each will be determined during the Remedial Design. The 10-acre capping scenario with the highest cost was used for this ROD. Each ofthe capping scenarios would minimize surface exposure, prevent inflltration ofwater that could create contaminated leachate, and prevent transport of wastes by erosion. Periodic maintenance would be required to maintain the integrity ofthe cap. ICs for this preferred remedial altemative for soil and waste material would include prohibition of activities that would damage the cap such as plowing, digging, drilling, trenching, or other earth movement. Shallow-root gardening for human consumption would also be prohibited. Groundwater use restrictions may include but not be limited to restrictions against using groundwater for drinking or irrigation. Other land use restrictions and engineering controls may be developed as the work on the Site progresses. The ODEQ will monitor and maintain the vegetation and soil to prevent erosion or movement ofthe cap to prevent exposure of metals-contaminated soil to humans and the environment.

Altemative 3 - Stabilization and.Off-Site Disposal at a RCRA-Permitted Facility associated costs are:

• Estimated Capital Cost-$33,623,370 • Estimated O&M Cost (30 yr)-$135,202 • Estimated Constraction Timeframe - 32 weeks • Estimated Time to Achieve RAOs - 32 weeks

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For this Altemative, approximately 164,000 yd' of contaminated soil and waste materials would be excavated, stabilized, and loaded onto trucks or railcars, and transported to an off-site permitted waste landfill for disposal. The off-site landfill would need to meet regulatory requirements for this type ofwaste. This altemative would permanently remove contaminated material from the Site and is a proven and acceptable practice that reduces the risk posed by hazardous substances. This altemative will achieve applicable RAOs and meet PRGs.

Altemative 4 - On-Site Fixation or Stabilization and On-Site Disposal associated costs are:

• Estimated Capital Cost-$14,251,359 • Estimated Annual O&M Cost - $356,678 • Estimated Constraction Timeframe - 30 weeks • Estimated Time to Achieve RAOs - 30 weeks

For this alternative approximately 164,000 yd' of contaminated soil and waste materials would be excavating for placement in an on-site disposal cell. The excavated areas would be backfilled with clean soil. The disposal cell would consist ofa clay liner and composite liner with leachate collection. Contaminated soil that is determined to be hazardous by characteristic or is wet would be stabilized so that it would be acceptable for placement in the cell.

The cell would be capped with compacted clay and topsoil. Capping would minimize surface exposure, prevent inflltration ofwater that could create contaminated leachate, and prevent transportation of wastes by erosion. Periodic maintenance would be conducted to maintain the integrity ofthe cap. ICs for this remedial altemative would include prohibition of shallow-root gardening for human consumption and all activities that would damage the cap such as plowing, digging, drilling, trenching or other earth movement. Prohibitions against using groundwater for drinking or irrigation purposes may be included. Vegetation and soil will be monitored and maintained to prevent erosion or movement ofthe cap. Also refer to the Common Element in part 1 of this section.

Post-closure groundwater monitoring would be conducted to determine if the cell and its contents are impacting the groundwater beneath the disposal cell and to verify that the cap retains its integrity. Every five years a formal review ofthe remedy will be required to ensure that it is protective. This altemative will achieve applicable RAOs and meet PRGs.

c. Sediment and Surface Water: On-site Ponds, Mid-site Ravine, and Strip Mine Pit

Altemative 2 - Stabilization and Off-Site Disposal at a RCRA-Permitted Facility associated costs are: (see b. Altemative 3 - Stabilization and Off-Site Disposal at a RCRA-Permitted Facility) -

Altemative 2 involves the removal of approximately 33,000 yd' of metals impacted sediment in

the onsite surface water features. The surface water features would be drained, with measures

taken to retain sediments within the AOC. The sediment would be dewatered, excavated, and

stabilized for loading and transport to an off-site permitted waste landfill for disposal. The off-

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site landfill would meet regulatory requirements for this type ofwaste. This altemative would permanently remove contaminated material from the Site and is a proven and acceptable practice that reduces the risk posed by hazardous substances. This altemative will achieve applicable RAOs and meet PRGs. Surface water features not requiring remediation would be left as is.

Altemative 3 - On-Site Fixation or Stabilization and On-Site Disposal is EPA and ODEQ's selected remedial altemative for on-site ponds, mid-site ravine, and strip mine pit. Altemative 3 associated costs are: (see b. Altemative 2 - Consolidation and Cap)

This altemative involves the removal of approximately 33,000 yd' of metals impacted sediment from the on-site surface water features. The surface water features would be drained and treated, if needed, with measures taken to retain sediments within the AOC. The sediment would be dewatered and stabilized, and excavated for loading and transport to the consolidation area or on-site disposal cell. After sediment removal, the surface water features would be backfilled with clean soil and re-graded.

The consolidation area or on-site disposal cell would be capped, see (b. On-Site Soil and Waste Materials Areas-Altemative 2). Other land use restrictions and engineering controls may be developed as the work on the site progresses. This altemative will achieve applicable RAOs and meet PRGs. Surface water features not requiring remediation would be left as is.

d. Soil, Sediment, and Waste: Off-Site Locations

Additional investigations may be conducted off-site to determine the nature and extent of contamination: those efforts are not part of this remedial action. Future investigations and

. remediation efforts may remain separate and be conducted by an interested third party and/or PRPs; or, residential contamination may be incorporated into this remedial response through an amended ROD or an Explanation of Significant Difference (ESD).

Altemative 2 - Excavation, Stabilization, and Disposal at the TFM Site is EPA and ODEQ's selected remedial altemative for off-site areas. Altemative 2 associated costs are:

• Estimated Capital Cost-$331,213 • Estimated Annual O&M Cost - $0

. • Estimated Construction Timeframe-12 weeks • Estimated Time to Achieve RAOs - 12 weeks

For this Altemative, approximately 1,600 yd' of contaminated soil, sediment, and waste materials would be excavated, stabilized (as needed), loaded onto tracks, and transported to the Site for disposal within a capped consolidation area or on-site disposal cell see (b. On-Site Soil and Waste Materials Areas-Altemative 2). The excavated areas would be backfilled with clean soil. This Altemative would permanently remove contaminated material from the off-site areas and is a proven and acceptable practice that reduces the risk posed by hazardous substances. This altemative will achieve applicable RAOs and meet PRGs. Other land use restrictions and engineering controls may be developed as the work on the site progresses.

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Altemative 3 - Excavation, Stabilization, and Off-Site Disposal at a RCRA-Permitted Facility associated costs are:

• Estimated Capital Cost - $706,680 • Estimated Annual O&M Cost - $0 • Estimated Constraction Timefreime - 12 weeks • Estimated Time to Achieve RAOs - 12 weeks

With this Altemative, approximately 1,600 yd' of contaminated soil, sediment, and waste materials would be excavated, stabilized (as needed), and loaded onto tmcks and transported to an off-site permitted waste landfill for disposal. The off-site landfill would meet regulatory requirements for this type ofwaste. The excavated areas would be backfilled with clean soil. This Altemative would permanently remove contaminated material from the off-site areas and is a proven and acceptable practice that reduces the risk posed by hazardous substances. This altemative will achieve applicable RAOs and meet PRGs. •

17. COMPARATIVE ANALYSIS OF ALTERNATIVES

Nine criteria are used to evaluate remedial altematives individually and against each other in order to select a remedy. These nine criteria are categorized into three groups: threshold, balancing, and modifying. The threshold criteria must be met in order for an altemative to be eligible for selection. The threshold criteria are overall protection of human health and the environment and compliance with applicable or relevant and appropriate requirements (ARARs). The balancing criteria are used to weigh major tradeoffs among altemat