RAE-9232/1-2 Volume I - DIFFUSE NORM WASTES - WASTE CHARACTERIZATION AND PRELIMINARY ... · 2014....

RAE-9232/1-2Volume I

- DIFFUSE NORM WASTES -

WASTE CHARACTERIZATIONAND PRELIMINARY RISK ASSESSMENT

Prepared by:

Jean-Claude DehmelSC&A, Inc.

1355 Beverly Road, Suite 250McLean, Virginia 22101

and

Vern C. RogersRogers & Associates Engineering Corp.

515 East 4500 SouthSalt Lake City, Utah 84107

Contract No. 68-D20-155Work Assignment 1-16

Prepared for:

U.S. Environmental Protection AgencyOffice of Radiation and Indoor Air

401 M Street, S.W.Washington, D.C. 20460

William E. RussoWork Assignment Manager

May 1993

iii

TABLE OF CONTENTS

Chapter Page No.

Executive Summary ES-1

A Introduction A-1

1 The Origins and Definitions of NORM Wastes A-12 Regulations of Norm Wastes A-63 Scope of the Report A-74 Exposure Scenarios Description A-105 Organization of the Report A-12

B.1 Uranium Mining Overburden B-1-1

1.1 Introduction B-1-11.2 Overview of the Uranium Mining Industry B-1-2

1.2.1 Surface Mining B-1-61.2.2 Underground Mining B-1-61.2.3 Other Mining Methods B-1-7

1.3 Uranium Ore and Overburden Production B-1-7

1.3.1 Waste Volume Estimates B-1-91.3.2 Reclaimed Versus Unreclaimed Material B-1-101.3.3 Present Waste Generation Rate B-1-12

1.4 Radiological Properties of Uranium Mine Overburden B-1-15

1.4.1 Radionuclide Concentrations B-1-151.4.2 Radon Flux Rates B-1-171.4.3 External Radiation Exposure Rates B-1-18

1.5 Uranium Overburden Utilization B-1-181.6 Disposal Scenario for Risk Assessments B-1-20

1.6.1 Scenario Description B-1-201.6.2 Representative Overburden Pile and Location

Characteristics B-1-21

iv

TABLE OF CONTENTS(Continued)

Chapter Page No.

1.7 Sector Summary B-1-22

B.2 Phosphate Industry Wastes B-2-1

2.1 Introduction B-2-12.2 Overview of the Phosphate Industry B-2-2

2.2.1 Phosphate Ore Beneficiation B-2-52.2.2 Phosphoric Acid - The Wet Process B-2-62.2.3 Elemental Phosphorus - The Thermal Process B-2-8

2.3 Phosphate Industry Waste B-2-11

2.3.1 Phosphogypsum Generation B-2-112.3.2 Slag Generation B-2-14

2.4 Radiological Properties of Phosphate Industry Wastes B-2-15

2.4.1 Radiological Properties of Phosphogypsum B-2-152.4.2 Radiological Properties of Slag B-2-19

2.5 Phosphate Industry Wastes Utilization B-2-24

2.5.1 Phosphogypsum Utilization B-2-242.5.2 Slag Utilization B-2-25

2.6 Disposal and Reuse Scenarios for Risk Assessments B-2-26

2.6.1 Phosphogypsum Disposal Scenario andCharacteristics B-2-26

2.6.2 Slag Disposal B-2-312.6.3 Reuse of Phosphogypsum B-2-342.6.4 Reuse of Slag B-2-36


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Chapter Page No.

B.3 Phosphate Fertilizers and Potash B-3-1

3.1 Introduction B-3-13.2 Overview of Fertilizer Production B-3-2

3.2.1 Phosphoric Acid Production B-3-23.2.2 Phosphate Fertilizer Production B-3-33.2.3 Potash Production B-3-3

3.3 Phosphate Fertilizer and Potash Consumption Rates B-3-43.4 Radiological Properties of Fertilizers B-3-7

3.4.1 Radionuclide Concentrations B-3-73.4.2 Radon Flux B-3-123.4.3 Radiation Exposure Rates B-3-12

3.5 Fertilizer Application Scenario for Risk Assessments B-3-13

3.5.1 Risk Assessment Scenario Description B-3-133.5.2 Representative Characteristics of Application of

Fertilizers B-3-14


B.4 Fossil Fuels - Coal Ash B-4-1

4.1 Introduction B-4-14.2 Overview of Coal Ash Generation B-4-3

4.2.1 Coal-Fired, Steam-Electric Generating Stations B-4-34.2.2 Industrial Boilers B-4-4

4.3 Coal Ash Generation and Management B-4-4

4.3.1 Production of Coal Ash B-4-44.3.2 Coal Ash Disposal B-4-114.3.3 Coal Ash Utilization B-4-11

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Chapter Page No.

4.4 Radiological Properties of Coal Ash B-4-20

4.4.1 Radionuclide Concentrations B-4-204.4.2 Radon Flux and Emanation Coefficient B-4-224.4.3 Previous Dose and Risk Assessments B-4-24

4.5 Disposal Scenarios for Risk Assessment B-4-25

4.5.1 Disposal Scenario Description B-4-254.5.2 Representative Disposal Facility and Location


4.6 Representative Reuse Scenario B-4-28

4.6.1 Reuse Scenario Description B-4-284.6.2 Radionuclide Concentrations B-4-32


B.5 Oil and Gas Production Sludge and Scale B-5-1

5.1 Introduction B-5-15.2 Overview of Oil and Gas Production B-5-45.3 Waste Production and Management of Oil and Gas Scale B-5-10

5.3.1 Origin and Nature of NORM in Oil and Gas Scale B-5-105.3.2 Oil and Gas Scale Production Rates B-5-145.3.3 Oil and Gas Scale Handling and Disposal B-5-17

5.4 Waste Production and Management of Oil and Gas Sludge B-5-18

5.4.1 Origin and Nature of NORM in Oil and Gas Sludge B-5-185.4.2 Oil and Gas Sludge Production Rates B-5-195.4.3 Oil and Gas Sludge Handling and Disposal B-5-22

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Chapter Page No.

5.5 Radiological Properties of NORM Contaminated Scale B-5-22

5.5.1 Radionuclide Concentrations in Scale B-5-225.5.2 Radon Fluxes in Scale B-5-255.5.3 External Radiation Exposures Rates from Scale B-5-25

5.6 Radiological Properties of NORM Contaminated Sludge B-5-30

5.6.1 Radionuclide Concentrations in Sludge B-5-305.6.2 Radon Fluxes in Sludge B-5-315.6.3 External Radiation Exposures Rates from Sludge B-5-32


5.7.1 Scenario Description B-5-325.7.2 Representative Disposal Facility and Location


5.8 Recycling Scenarios of Scale-Coated Steel for RiskAssessment B-5-38

5.8.1 Representative Reuse and Location Characteristics B-5-385.8.2 Reprocessing Scenario B-5-40


B.6 Water Treatment Sludge B-6-1

6.1 Introduction B-6-16.2 Overview of Water Supply Systems B-6-2

6.2.1 Areas of Elevated Water Radionuclide Concentrations B-6-26.2.2 Water Treatment Technology B-6-5

6.3 Water Treatment Waste Generation B-6-11

6.3.1 Water Treatment Waste Generation B-6-11

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Chapter Page No.

6.3.2 Water Treatment Waste Disposal Methods B-6-136.3.3 Generation Rate of NORM-Contaminated Sludge B-6-17

6.4 Radiological Properties of Treatment Sludge B-6-19

6.4.1 Radionuclide Concentrations B-6-196.4.2 Radon Fluxes B-6-236.4.3 External Radiation Exposure Rates B-6-24

6.5 Disposal and Reuse Scenarios for Risk Assessments B-6-25

6.5.1 Water Treatment Waste Disposal Scenario andCharacteristics B-6-25

6.5.2 Reuse of Water Treatment Sludges B-6-27


B.7 Metal Mining and Processing Waste B-7-1

7.1 Introduction B-7-17.2 Overview of the Metal Mining Industry B-7-5

7.2.1 Metal Mining and Waste Production B-7-57.2.2 Rare Earths B-7-87.2.3 Bauxite and Aluminum B-7-117.2.4 Copper B-7-137.2.5 Zinc B-7-167.2.6 Tin B-7-167.2.7 Titanium B-7-177.2.8 Zirconium and Hafnium B-7-197.2.9 Ferrous Metals (Iron and Carbon Steel) B-7-197.2.10 Lead B-7-22

7.3 Processing Waste Generation B-7-24

7.3.1 Rare Earths B-7-247.3.2 Zirconium, Hafnium, Titanium, and Tin B-7-25

ix


Chapter Page No.

7.3.3 Large Waste Volume Processes B-7-27

7.4 Radiological Properties of Mining and Processing Wastes B-7-38

7.4.1 Rare Earths B-7-387.4.2 Zirconium, Hafnium, Titanium, and Tin B-7-407.4.3 Large Waste Volume Processes B-7-43


7.5.1 Scenario Description B-7-527.5.2 Representative Disposal and Facility

Characteristics for Rare Earths B-7-537.5.3 Representative Disposal and Facility

Characteristics for Zirconium, Hafnium, Titanium,and Tin B-7-54

7.5.4 Representative Disposal and FacilityCharacteristics for Large Waste Volume Processes B-7-58

7.6 Reuse Scenarios for Risk Assessment B-7-64

7.6.1 Reuse Scenario Description B-7-647.6.2 Population Exposure B-7-707.6.3 Radionuclide Concentrations B-7-72


B.8 Geothermal Energy Production Waste B-8-1

8.1 Introduction B-8-18.2 Overview of the Geothermal Energy Industry B-8-3

8.2.1 Electrical Power Production B-8-58.2.2 Direct Use of Geothermal Energy B-8-12

x


Chapter Page No.

8.3 Geothermal Energy Waste B-8-13

8.3.1 Geothermal Energy Waste Generators B-8-138.3.2 Annual Waste Generation Estimate B-8-15

8.4 Radiological Properties of Geothermal Energy Wastes B-8-16

8.4.1 Radionuclide Concentrations B-8-168.4.2 Radon Flux B-8-18

8.5 Disposal Scenarios for Risk Assessments B-8-18

8.5.1 Scenario Description B-8-188.5.2 Representative Geothermal Solid Waste Facility

and Location Characteristics B-8-21


C Past and Current Practices and Exposure Potential C-1

1 Introduction C-12 Overview of Current Use and Disposal Practices C-1

2.1 Uranium Overburden C-12.2 Phosphate Waste C-22.3 Phosphate Fertilizers C-22.4 Coal Ash C-22.5 Oil and Gas Pipe Scale C-22.6 Water Treatment Residues C-32.7 Mineral Processing Waste and Materials C-32.8 Geothermal Energy Production Waste C-3

3 Contamination Incidents C-4

3.1 Recycling of Contaminated Scrap in Steel Mills C-53.2 Improper Landfill Disposal C-6

xi


Chapter Page No.

3.3 Planned and Approved Landfill Disposal C-73.4 A Specifically Authorized Application C-83.5 Other Events C-8

4 Current Federal Remedial Programs Dealing with NORM Waste C-13

4.1 FUSRAP Program C-144.2 Superfund Sites C-164.3 UMTRCA Program C-21

D.1 Risk Assessment Methodology D-1-1

1.1 Overview of Scenarios and Exposure Pathways D-1-11.2 Scenario Characteristics and Pathway Equations D-1-6

1.2.1 Worker -- Direct Gamma Exposure D-1-71.2.2 Worker -- Dust Inhalation D-1-81.2.3 Worker -- Indoor Radon Inhalation D-1-91.2.4 On-Site Individual - Direct Gamma Exposure D-1-101.2.5 On-Site Individual - Dust Inhalation D-1-111.2.6 On-Site Individual -- Indoor Radon Inhalation D-1-121.2.7 Member of the CPG -- Direct Gamma Exposure D-1-121.2.8 Member of the CPG -- Inhalation of Contaminated

Dust D-1-141.2.9 Member of the CPG -- Downwind Exposure to Radon D-1-161.2.10 Member of the CPG -- Gamma Exposure from

NORM in Building Materials D-1-181.2.11 Member of the CPG - Radon Inhalation from NORM

in Building Materials D-1-191.2.12 Member of the CPG -- Ingestion of Drinking Water

from a Contaminated Well D-1-201.2.13 Member of the CPG -- Ingestion of Food

Contaminated by Well Water D-1-231.2.14 Member of the CPG -- Ingestion of Food

Contaminated by Dust Deposition D-1-241.2.15 Member of the CPG -- Ingestion of Food Grown

on Repeatedly Fertilized Soils D-1-25

xii


Chapter Page No.

1.2.16 Member of the CPG -- Exposure to Radiationfrom Road Pavement and Aggregate D-1-26

1.2.17 Member of the CPG -- Inhalation of ContaminatedDust from Stack Releases D-1-29

1.2.18 General Population -- Downwind Exposure toResuspended Particulates D-1-31

1.2.19 General Population -- Downwind Exposure to Radon D-1-331.2.20 General Population -- Ingestion of River Water

Contaminated via the Groundwater Pathway D-1-341.2.21 General Population -- Ingestion of River Water

Contaminated by Surface Runoff D-1-351.2.22 General Population -- Ingestion of Foodstuffs Brown

on Repeatedly Fertilized Soil D-1-371.2.23 General Population -- Downwind Exposure from

Stack Releases D-1-381.2.24 Summary of Scenario and Pathway Characterization D-1-40

D.2 Risk Assessment Parameters D-2-1

2.1 Uranium Mining Overburden Disposal Parameters D-2-12.2 Phosphate and Elemental Phosphorous Wastes D-2-4

2.2.1 Disposal Scenario Parameters for Phosphogypsum D-2-42.2.2 Disposal Scenario Parameters for Slag D-2-42.2.3 Reuse Scenario Parameters for Phosphogypsum D-2-52.2.4 Reuse Scenario Parameters for Phosphate Slag D-2-5

2.3 Phosphate Fertilizers Disposal Parameters D-2-82.4 Fossil Fuels - Coal Ash D-2-8

2.4.1 Disposal Scenario Parameters for Coal Ash D-2-82.4.2 Reuse Scenario Parameters for Coal Ash D-2-9

2.5 Oil and Gas Production Scale and Sludge D-2-10

2.5.1 Disposal Scenario Parameters for Oil and GasProduction Scale and Sludge D-2-10

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Chapter Page No.

2.5.2 Reuse Scenario Parameters for Oil ProductionScale D-2-10

2.6 Water Treatment Sludge D-2-10

2.6.1 Disposal Scenario Parameters for Water TreatmentSludge D-2-10

2.6.2 Reuse Scenario Parameters for Water TreatmentSludges D-2-11

2.7 Metal Mining and Processing Wastes D-2-11

2.7.1 Disposal Scenario Parameters for Rare Earths D-2-112.7.2 Disposal Scenario Parameters for Zirconium,

Hafnium, Titanium, and Tin D-2-122.7.3 Disposal Scenario Parameters for Large Waste

Volume Processes D-2-122.7.4 Reuse Scenario Parameters for Metal Mining and

Process Wastes D-2-13

2.8 Geothermal Energy Waste Disposal Scenario Parameters D-2-132.9 Summary of Site-Specific Risk Assessment Parameters D-2-142.10 Summary of Generic Risk Assessment Parameters D-2-15

D.3 Risk Assessment Results D-3-1

3.1 Worker Doses and Risks from Storage or Disposal D-3-43.2 Doses and Risks to On-Site Individuals from Storage

or Disposal D-3-93.3 Doses and Risks to Members of the Critical Population

Group from Storage or Disposal D-3-93.4 Population Doses and Health Effects from Storage or Disposal D-3-113.5 Benchmarking the Dose Methodology D-3-113.6 Summary and Conclusions Concerning Storage and Disposal of

Diffuse NORM Wastes D-3-133.7 Worker Doses and Risks from Reuse D-3-213.8 Doses and Risks to On-Site Individuals from Reuse D-3-21

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Chapter Page No.

3.9 Doses and Risks to Members of the Critical PopulationGroup from Reuse D-3-25

3.10 Population Doses and Health Effects from Reuse D-3-253.11 Summary and Conclusions Concerning Reuse of Diffuse NORM

Wastes D-3-27

E.1 Conclusions E-1-1

1.1 Risks from Storage or Disposal E-1-31.2 Risks from Reuse E-1-51.3 Summary E-1-6

E.2 Recommendations E-2-1

2.1 Radiological Source Term E-2-22.2 Environmental Transport Mechanism Recommendations E-2-42.3 Exposure Pathways E-2-52.4 Exposed Populations E-2-62.5 Evaluation of Overall Uncertainties E-2-7

xv

LIST OF FIGURES

Figure No. Page No.

A-1 Uranium-238 decay series A-2

A-2 Thorium-232 decay series A-3

A-3 Uranium-235 (Actinium) decay series A-4

B.2-1 Major Uraniferous phosphate deposits in the U.S. B-2-3

B.2.2 Flow diagram of phosphate material and waste production B-2-4

B.5-1 Typical production operation, showing separation of oil, gas and water B-5-12

B.8-1 Schematic of electric power production from a vapor-dominated system B-8-6

B.8-2 Schematic of flashed-steam process for producingelectric power from a liquid-dominated system B-8-7

B.8-3 Schematic of binary process for producing electricpower from a liquid-dominated system B-8-8

D.3-1 Lifetime risks to the CPG from the disposal of NORM D-3-2

D.3-2 Health effects to the general population from the disposal ofNORM at the reference site D-3-3

D.3-3 Health effects to the general population from the generation ofone year's waste D-3-5

D.3-4 Health effects to the general population from one year's reuse D-3-6

xvii

LIST OF TABLES

Table No. Page No.

A-1 Risk assessment exposure scenarios for diffuse NORM storageand disposal A-8

A-2 Risk assessment exposure scenarios for reuse of diffuse NORM A-9

B.1-1 Location of surface and underground uranium minesites in the U.S. B-1-3

B.1-2 Estimated uranium ore and overburden production B-1-4

B.1-3 Surface uranium mining industry based on regionalreclamation B-1-13

B.1-4 Radionuclide concentrations in uranium mining overburden B-1-16

B.1-5 Risk assessment parameters for representative disposal of uraniummining overburden B-1-23

B.2-1 Wet process phosphoric acid plants B-2-7

B.2-2 Location and capacity of elemental phosphorus plants B-2-10

B.2-3 Location and number of phosphogypsum stacks B-2-13

B.2-4 Radionuclide concentrations in phosphate ores,phosphogypsum, and slag B-2-16

B.2-5 Radionuclide concentrations in phosphogypsum B-2-17

B.2-6 Radionuclide concentrations in phosphate slag B-2-20

B.2-7 Summary of dose and risk results from the Idahoradionuclide exposure study B-2-23

B.2-8 Risk assessment parameters for the representative disposal ofphosphogypsum B-2-29

xviii

LIST OF TABLES(Continued)

Table No. Page No.

B.2-9 Risk assessment parameters for the representative disposal ofphosphate slag B-2-32

B.2-10 Radionuclide concentrations for phosphogypsumreuse in agriculture B-2-37

B.2-11 Risk assessment parameters for the representative reuse ofphosphogypsum B-2-38

B.2-12 Radionuclide concentrations in road base slag andconcrete road surface B-2-42

B.2-13 Risk assessment parameters for the representative reuse ofphosphate slag B-2-43

B.3-1 Trends in phosphate fertilizer demand and application B-3-5

B.3-2 Phosphate fertilizer consumption in the year endingJune 30, 1988 B-3-6

B.3-3 Typical radionuclide concentration in fertilizers B-3-9

B.3-4 Radionuclide concentrations in the average fertilizer B-3-11

B.3-5 Radionuclide concentrations in repeatedly fertilized soil B-3-17

B.3-6 Risk assessment parameters for the representative application ofphosphate fertilizers and potash B-3-18

B.4-1 Coal production summary B-4-2

B.4-2 Constituents of coal ash B-4-7

B.4-3 Yearly ash production rate B-4-8

B.4-4 Regional fly ash production and utilization-1984 B-4-10

xix


Table No. Page No.

B.4-5 Ash and sludge utilization breakdown for 1990 B-4-13

B.4-6 Yearly ash utilization rate B-4-18

B.4-7 Estimated doses and risk from exposure to a coalash pile B-4-26

B.4-8 Risk assessment parameters for the representative disposal ofcoal ash B-4-29

B.5-1 U.S. crude oil and natural gas production B-5-5

B.5-2 Crude oil production for 1989 by state B-5-6

B.5-3 Natural gas production for 1989 by state B-5-8

B.5-4 Summary of NORM waste generated by a 10-well production facility B-5-15

B.5-5 Summary of NORM sludge generated by a 10-wellproduction facility B-5-20

B.5-6 Summary Tabulation of radiation exposure levelsassociated with NORM in oil production and gasprocessing equipment B-5-26

B.5-7 Abbreviations used to designate equipment typesin oil production and gas processing facilities B-5-28

B.5-8 Risk assessment parameters for the representative disposal of oiland gas waste B-5-36

B.5-9 Risk assessment parameters for the representative cycle of oiland gas waste B-5-41

B.6-1 Numbers of public water systems and populations served by sources and size category B-6-6

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Table No. Page No.

B.6-2 Summary of treatment technologies for removal ofnaturally occurring radionuclides from water B-6-7

B.6-3 Distribution of water treatment systems reported in use by 211 water utilities surveyed in 1985 B-6-9

B.6-4 Summary of water utilities operating characteristicsreported in 1984 and 1985 surveys B-6-12

B.6-5 Sludge disposal practices and quantities for 183utilities in 29 selected states B-6-14

B.6-6 Ra-226 concentration in raw water and dry lime sludge B-6-21

B.6-7 Estimated radionuclide concentration in water treatment sludge B-6-22

B.6-8 Radionuclide concentrations in the landfill B-6-28

B.6-9 Risk assessment parameters for the representative disposal ofphosphogypsum B-6-29

B.6-10 Estimated radionuclide concentrations in watertreatment sludge used in agriculture B-6-33

B.6-11 Risk assessment parameters for the representative application ofwater treatment sludge B-6-34

B.7-1 Metal mining industries known or believed to involve enhanced levels of NORM B-7-4

B.7-2 Estimated amounts of extraction and beneficiationwastes generated in 1987 B-7-7

B.7-3 Rare earth processing facilities as of 1989 B-7-10

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Table No. Page No.

B.7-4 Bauxite refineries B-7-12

B.7-5 Primary copper processing facilities B-7-15

B.7-6 Domestic titanium tetrachloride procedures B-7-18

B.7-7 Domestic iron and steel producers B-7-21

B.7-8 Primary lead processing facilities in the U.S. B-7-23

B.7-9 Estimated annual waste generated from production of zirconium, hafnium, titanium, and tin B-7-26

B.7-10 Estimated amount of waste generated by theextraction and beneficiation of metal ores in 1980 B-7-28

B.7-11 Specific wastes generated by ferrous metals facilities in 1988 B-7-32

B.7-12 Uses of iron blast furnace slag in 1988 B-7-33

B.7-13 Uses of steel furnace slag in 1988 B-7-34

B.7-14 Estimated slag volumes generated during 1988 fromprocessing raw ores to produce primary metals B-7-37

B.7-15 Radionuclide concentrations in alumina plantprocess samples B-7-44

B.7-16 Bauxite open-pit mine surface radon flux rates B-7-45

B.7-17 Radionuclide concentrations in copper materials B-7-47

B.7-18 Selected uranium bearing metalliferous depositsin Arizona B-7-48

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Table No. Page No.

B.7-19 Radionuclide source term for rare earth metal mining and processing wastes B-7-55

B.7-20 Risk assessment parameters for representative disposal ofrare earth wastes B-7-56

B.7-21 Radionuclide source term for rare earth metal mining andprocessing wastes B-7-59

B.7-22 Risk assessment parameters for representative disposal ofSr, Hf, Ti, and Sn B-7-60

B.7-23 Radionuclide source term for large volume and metal miningand processing wastes B-7-63

B.7-24 Risk assessment parameters for representative disposal oflarge waste processes B-7-65

B.7-25 Uses of metal mining waste and tailings B-7-67

B.7-26 Uses of mineral processing slag B-7-71

B.7-27 Radionuclide source term for reuse of metal miningand processing wastes B-7-73

B.8-1 Summary of geothermal drilling activity by state from 1981 to 1985 B-8-4

B.8-2 Geothermal plants for electricity generation B-8-10

B.8-3 Radionuclide distribution and concentrations inwaste samples from the Vulcan, Del Ranch, Elmore, and Leathers geothermal power plants B-8-17

B.8-4 Estimated radionuclide concentrations in geothermalenergy production waste B-8-19

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Table No. Page No.

B.8-5 Risk assessment parameters for representative disposal of solidgeothermal wastes B-8-23

C-1 Summary status of the Montclair, West Orange,and Glen Ridge, NJ, remediation characteristics C-19

D.1-1 Risk assessment exposure scenarios for diffuseNORM storage and disposal D-1-4

D.1-2 Risk assessment exposure scenarios for reuse of diffuse NORM D-1-5

D.1-3 Preliminary risk assessment equation reference summary D-1-41

D.2-1 Reference disposal pile parameters and radionuclideconcentrations for diffuse NORM waste disposal riskassessment D-2-2

D.2-2 Reference parameters and radionuclide concentrationsfor diffuse NORM reuse risk assessment D-2-6

D.2-3 Generic input parameters for diffuse NORM risk assessment D-2-16

D.2-4 Dose and risk conversion factors D-2-18

D.2-5 Equivalent uptake factors D-2-20

D.3-1 Estimated worker doses and risks from storageor disposal of diffuse NORM D-3-7

D.3-2 Estimated risks from radon inhalation from storageor disposal of diffuse NORM D-3-8

D.3-3 Individual doses and risks from storage or disposal of diffuse NORM D-3-10

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Table No. Page No.

D.3-4 Population doses and health effects from storageor disposal of diffuse NORM D-3-12

D.3-5 Benchmark of methodology for oil and gas scale/sludge D-3-14

D.3-6 Summary of dominant risks to workers from one yearof exposure D-3-15

D.3-7 Summary of risks to the on-site individual groupfrom one year of exposure D-3-16

D.3-8 Summary of dominant estimated risks to the criticalpopulation group from one year of exposure D-3-17

D.3-9 Summary of estimated cumulative health effects perreference site from one year of exposure D-3-19

D.3-10 Summary of estimated cumulative health effects fromone year of exposure to one year's waste D-3-20

D.3-11 Estimated worker doses and risks from reuse of diffuse NORM D-3-22

D.3-12 Estimated risks from radon inhalation from reuse of diffuse NORM D-3-23

D.3-13 Estimated individual doses and risks from reuse of diffuse NORM D-3-24

D.3-14 Estimated population doses and health effects from reuse of diffuse NORM D-3-26

D.3-15 Summary of estimated cumulative health effectsfrom one year of exposure to one year's reusedwaste D-3-29

E.2-1 Uncertainty ranking E-2-8

ES-1

Executive Summary

ES.1 INTRODUCTION

In September 1989, the Environmental Protection Agency (EPA) released a preliminary draft risk

assessment characterizing generation and disposal practices for wastes that contain relatively low

levels of naturally-occurring radioactive materials (NORM). Such wastes are typically generated

in large volumes and, in some cases, may be put to commercial uses instead of being disposed

of as wastes. The draft risk assessment report was prepared as an initial step to help determine

if standards governing the disposal and reuse of NORM waste and material are warranted.

Diffuse NORM wastes and materials are of such large volumes and relatively low radionuclide

concentrations that it was deemed inappropriate to include them within the scope of other

proposed rulemaking activities. A second draft risk assessment was issued in May 1991.

Comments on the draft reports indicated that there was a need to further review the data,

assumptions, and models used in those reports, provide additional information on categories of

diffuse NORM waste that were not explicitly addressed, and perform additional risk assessments.

This report, prepared in response to those recommendations, presents the results of further

characterization efforts and an updated and revised risk analysis. As with the earlier reports, the

analyses presented here are only intended to help the EPA consider whether regulations for

diffuse NORM need to be developed. If EPA decides regulation is warranted, a much more

detailed and complete risk analyses and waste characterization will be developed and presented

in a Background Information Document that will accompany proposed regulations.

ES.2 WASTE VOLUME AND ACTIVITY SUMMARY

All soils and rocks are known to contain some amounts of naturally-occurring radioactive

material (NORM). The major radionuclides are uranium and thorium, and their respective decay

products. Radium, one of the decay products, and its subsequent decay products, are the

principal radionuclides of concern in characterizing the redistribution of radioactivity in the

environment by human activity. Radium is normally present in soil in trace concentrations of

ES-2

about one picocurie per gram (pCi/g). Certain industrial processes, however, tend to concentrate

the radioactivity to much higher levels in the resulting waste or byproduct material. Other

industrial processes may simply make it more accessible to humans. Such processes include

mining and beneficiation, mineral processing, coal combustion, and drinking water treatment,

among others. Some of the NORM wastes or materials are generated in large quantities and are

typically disposed or stored at the point of generation. At times, however, NORM materials and

wastes are used in various applications instead of being disposed. Both disposal and reuse may

result in unnecessary radiation exposures, potential adverse health effects, and environmental

contamination.

NORM waste generation, reuse, and disposal practices are characterized in this report for eight

NORM sectors. The largest inventories of NORM waste are associated with metal mining

mineral processing, phosphorous production, uranium mining, and ash from coal combustion in

utility and industrial boilers. Each of these processes generates large volumes of waste with

annual production rates of several million metric tons. Annually, these NORM sectors can

generate in excess of one billion metric tons of waste. Smaller amounts of wastes are generated

by the petroleum industry as oil and gas pipe scale and sludge, from geothermal energy

production, and by drinking water treatment facilities. Phosphate fertilizers, while not a waste,

are included in this analysis for perspective because of their elevated radium concentrations. It

is estimated that nearly 5 million metric tons of these fertilizers are applied to agricultural fields

annually.

Section ES.2 presents a summary of NORM waste generation practices, annual waste generation

rates, and average NORM radionuclide concentrations, as summarized in Table ES-1. Utilization

practices are discussed in Section ES.3 and the preliminary risk assessment is summarized in

Section ES.4.

ES-3

Table ES-1. Present production and Radium-226 concentrations in NORM waste.a

Material orWaste Stream

PresentProduction Rate

(metric tons per year)

Average Ra-226Concentration

(pCi/g)bAddressedin Chapter

Uranium Mining Overburden 38 million 25 B.1

Phosphate Waste - Phosphogypsum - Slag - Scale

50 million48 million1.6 million

3,000 m3

3335

(1,000)

B.2

Phosphate Fertilizers 5 million 8.3 B.3

Coal Ash - Fly ash - Bottom ash and slag

61 million44 million17 million

3.7(3.9)(3.1)

B.4

Oil and Gas Scale and Sludge

260 thousand 90 B.5

Water Treatment - Sludges - Radium selective resins

300 thousand260 thousand40 thousand

1616

(35,000)

B.6

Metal Mining and Processing - Rare Earths - Zirconium, Hafnium, Titanium, and Tin - Large Volume Industries (e.g., copper, iron)

1.0 billion21 thousand

470 thousand

1.0 billion

(5)90043

5

B.7

Geothermal Energy Production Wastes

54 thousand 132 B.8

____________________a See text for details and assumptions both here and in the preceding subsections.b Average Ra-226 concentrations are shown for comparative purposes. The risk assessment,

however, considers other radionuclides, such as uranium, thorium, and their decayproducts. Concentrations shown in parentheses are included for illustrative purposes.These values are not used in the risk assessment. See each respective subsection fordetails.

ES-4

ES.2.1 Uranium Mining Overburden

The uranium industry currently generates about 38 million metric tons (MT) of overburden per

year, based on 1988 data. The total inventory of unreclaimed overburden is estimated to be 3.1

billion MT. Much of this waste consists of soil and rock which has been removed to uncover

underlying uranium deposits. Uranium overburden is used only in a limited number of

applications, typically for backfilling mined out areas and to construct site roads. For this report,

the average Ra-226 concentration in overburden waste is assumed to be 25 pCi/g.

ES.2.2 Phosphate Waste

It is estimated that the current inventory of phosphogypsum waste is 8 billion MT. The yearly

phosphogypsum generation rate has averaged nearly 40 million MT since 1984. An additional

800 million MT of phosphogypsum will be added to the existing inventory over the next 20

years. Phosphogypsum is a by-product material generated during the production of phosphoric

acid. Essentially all of the phosphogypsum is stored in waste piles, called stacks. Under the

Clean Air Act, 40 CFR 61, EPA regulates phosphogypsum. Only a very small fraction of the

phosphogypsum that is produced yearly is put to use (e.g., applied as a soil conditioner). The

presence of radium in phosphate rock is known to vary from low concentrations that are nearly

identical to those found in soils to levels as high as 60 pCi/g.

Elemental phosphorus plants, which use phosphate rock as feedstock, produce an estimated 1.6

million MT of slag waste per year. Slag is a vitrified waste resulting from processing phosphate

rock in high temperature furnaces. The resulting waste is also high in radium (10 to 60 pCi/g).

Slag material has been used in the past as an aggregate in making roads, streets, pavements,

residential structures, and buildings. For this report, an average Ra-226 concentration of 33 pCi/g

is assumed for phosphogypsum, and an average Ra-226 concentration of 35 pCi/g is assumed for

slag. These values are based on measured data.

ES-5

ES.2.3 Phosphate Fertilizers

In the context of this report, phosphate fertilizers are not assumed to be waste. The yearly

consumption of fertilizers has averaged close to 5 million MT over the past nine years. Fertilizer

application rates are known to vary depending upon the type of crops and soils. A typical

phosphate fertilizer application rate is about 40 kg per hectare. Fertilizers are available in over

100 different blends with varying concentrations of nitrogen, phosphorus, and potassium.

Fertilizers have varying Ra-226 concentrations (5 to 33 pCi/g) depending upon the type of blend

and origin of the phosphate rock. The average Ra-226 concentration in fertilizers is assumed to

be 8.3 pCi/g in this assessment. The resulting increase in Ra-226 soil concentration is only on

the order of 0.002 pCi/g for 20 years of repeated fertilizer applications. By comparison, natural

soils contain radium in concentrations ranging from 0.1 to 3 pCi/g.

ES.2.4 Fossil Fuels - Coal Ash

Utility and industrial boilers are estimated to generate about 61 million MT of coal ash per year.

Of this total amount, nearly 20 million MT are used in a variety of applications instead of being

sent to disposal facilities. Coal ash is primarily being used as an additive in concrete, as a

structural fill, and for road construction. The presence of radium in coal is known to vary over

two orders of magnitude depending upon the type of coal and region from which it has been

mined. The amount of ash generated during combustion is primarily dependent upon the mineral

content of the coal and type of boiler. Coal ash generally consists of fly ash, bottom ash, and

boiler slags. Ra-226 concentrations in coal may be as low as a fraction of a picocurie per gram

to as high as 20 pCi/g. For this report, the average coal ash Ra-226 concentration is assumed

to be 3.7 pCi/g.

ES.2.5 Oil and Gas Production Scale and Sludge

The types of waste generated by the petroleum industry include pipe scale, sludge, and equipment

or components contaminated with radium. It is estimated that the industry generates about

ES-6

150,000 cubic meters or 260,000 MT of such waste yearly. Field surveys have shown that

petroleum pipe scale may have very high Ra-226 concentrations, in some cases more than

400,000 pCi/g. Some of this waste is retained in oil and gas production equipment, while some

of the scale and sludge is presently being removed and stored in drums. The industry disposes

of scale and sludge wastes removed from oil and gas production equipment and also discards

associated contaminated components. The complex geometry and internal structures of such

equipment makes this characterization difficult. For this report, it is assumed that a typical

concentration of Ra-226 in scale is 360 pCi/g and in sludge is 75 pCi/g. The mass-weighted

average Ra-226 for this sector is 90 pCi/g.

ES.2.6 Water Treatment Sludge

It is estimated that water supply systems generate a yearly total of 3.1 million MT of waste,

including sludge and other waste forms as well. Of this, it is estimated that about 700 water

utilities generate 300,000 MT of NORM waste yearly, including sludge, and spent resin and

charcoal beds. Most of this waste is disposed in landfills and lagoons, or is applied to

agricultural fields.

Water treatment wastes are thought to contain low concentrations of Ra-226, comparable to

those found in typical soils. However, some water supply systems, primarily those relying on

groundwater sources, may generate sludge with much higher Ra-226 levels. Furthermore, some

water treatment systems are more effective than others in removing naturally occurring

radionuclides from the water. The bulk of the NORM-contaminated waste is believed to be in

the form of sludge. For this report, it is assumed that the average Ra-226 concentrations in such

waste is 16 pCi/g, based on Ra-226 concentration of 8 pCi/L in the influent.

ES.2.7 Metal Mining and Processing Waste

The metal mining and processing industry currently generates about 1 billion MT of waste yearly,

excluding phosphate and asbestos related wastes. It has been estimated that the total waste

ES-7

inventory since the turn of the century is nearly 50 billion MT. Much of the metal mining waste

is stored on site or near the point of generation. Metal mining processing wastes have only been

reused in a limited number of applications, typically for backfilling mined out areas and for

construction and roadbuilding near the mines. Some of the wastes are in fact stockpiles that are

processed several times to extract additional minerals. Although the bulk of the waste is of low

radium concentration, about one percent, mainly from monazite sands, zircon sands, ilmenite, and

columbium, have elevated radium levels. Overall, mineral processing wastes, for metals such as

rare earths, lead, iron, aluminum, and copper, generate large volumes of waste with extremely

variable Ra-226 concentrations. This report addresses the metal mining and processing sector

in three parts, representing mining and processing rare earths; zirconium, hafnium, titanium, and

tin; and large volume metals such as copper and iron. The estimated Ra-226 concentrations for

these three parts are 900 pCi/g, 43 pCi/g, and 5 pCi/g, respectively.

ES.2.8 Geothermal Energy Production Waste

Geothermal energy currently makes a relatively minor contribution to total U.S. energy

production. The primary geothermal development sites in the U.S. are the Geysers, in Sonoma

County in northern California, and the Imperial Valley in southern California. The only

significant NORM-contaminated wastes from geothermal power production are the solid wastes

originating from the treatment of spent brines such as in Imperial Valley. The hot saline fluids

from geothermal reservoirs in that area may have a dissolved solids content approaching 30

percent by weight. The estimated annual generation rate of geothermal energy production waste

is 54 thousand metric tons. The estimated average Ra-226 concentration in this waste is 132

pCi/g, based on data from southern California geothermal power production facilities.

ES.3 PAST AND CURRENT PRACTICES AND EXPOSURE POTENTIAL

There have been a number of cases where the improper disposal of NORM wastes has resulted

in increased levels of direct gamma exposure to individuals. In Montclair, New Jersey, radium

contaminated soil caused higher than normal direct gamma radiation exposure levels. The use

ES-8

of elemental phosphorus slag to construct roads in Pocatello, Idaho has resulted in a doubling of

the natural background radiation levels in some areas. In Mississippi, the use of pipes

contaminated with radium scale in playgrounds and welding classes has resulted in some

unnecessary radiation exposures to students using that equipment.

Several forms of diffuse NORM wastes are being disposed or used in a variety of manners.

Phosphate waste is placed in large stacks where it is produced, with some of the waste

subsequently being used for agricultural or construction purposes. In the past, homes have been

built over land containing phosphogypsum waste. Uranium mining overburden is piled and

stabilized where it is mined, with little or no subsequent use except to reclaim the land at the

mine.

Coal ash is placed in on-site storage ponds, surface impoundments, and sanitary landfills, as well

as being reused in road construction, embankments, and in cement aggregates. Water treatment

plant residues are placed in ponds and sanitary landfills, or spread on agricultural soils.

Phosphate fertilizers are, of course, spread on agricultural lands.

Mineral processing wastes are generally disposed in tailings ponds or used to construct dams,

dikes, or embankments. Small amounts of waste have been used off site for backfill, aggregate

production, or for road building. Some mineral processing wastes have been used to make

wallboard and concrete. Oil and gas pipe scale and sludge from the petroleum industry, which

is being studied intensely, is being stored until a proper disposal method can be identified in

some states. In the past, however, much of the oil and gas scale and sludge was placed in

collection ponds, and some radium-contaminated piping from oil production was donated to

schools or other organizations.

The contamination of groundwater from NORM wastes has occurred in a few instances. In most

cases, however, radium is relatively immobile and does not move into groundwater very quickly.

An exception to this may be mineral processing wastes containing radium in the chloride form,

which appears to have a much higher mobility. Groundwater contamination also has been

ES-9

associated with uranium mining waste and from the improper disposal of radium contaminated

pipe scale.

Improper use or disposal of diffuse NORM wastes could result in significant contamination of

the environment, as well as having adverse impacts on individual and public health. In fact, the

unregulated use or disposal of waste containing elevated concentrations of radium has resulted

in contamination of soil and groundwater, and elevated radiation exposures to individuals. In

addition, further research is taking place to identify new applications for use of NORM wastes.

If care is not taken to balance risks and benefits from such applications, this could lead to

unacceptable radiation exposures to the public.

ES.4 PRELIMINARY RISK ASSESSMENT

The risk analysis addresses several pathways for exposures to disposal site workers, persons who

occupy the site after it is closed (on-site individuals), members of the critical population group

(CPG), and the general population for each of the eight NORM waste sectors. The CPG are

assumed to be individuals who receive the highest off-site risks in the course of their normal

daily activities. The general population is assumed to live or work within 50 miles of the

reference sites. Exposures from both disposal and reuse of NORM wastes were estimated.

Exposure pathways evaluated include: direct external gamma, dust inhalation, radon gas and

radon decay product inhalation, ingestion of river and well water, and ingestion of foods

contaminated by well or river water, dust deposition, or fertilized soils.

ES.4.1 Storage and Disposal

A summary of the lifetime risks per year of exposure to members of the CPG is shown in Figure

ES-1. The phosphate fertilizer and water treatment sludges had lifetime risks less than 10-7.

Conversely, uranium mining overburden, phosphogypsum, phosphate slag, coal ash, oil and gas

scale and sludge, rare earths mining and processing, and geothermal sectors had lifetime risks

exceeding 10-6. None had risks exceeding 10-3.

ES-10

1.00E-8

1.00E-7

1.00E-6

1.00E-5

1.00E-4

1.00E-3

1.00E-2

LIF

ET

IME

RIS

K

UR

AN

IUM

MIN

ING

OV

ER

BU

RD

EN

PH

OS

PH

OG

YP

SU

M W

AS

TE

S

PH

OS

PH

AT

E S

LA

G

PH

OS

PH

AT

E F

ER

TIL

IZE

RS

CO

AL

AS

H

OIL

& G

AS

SC

AL

E/S

LU

DG

E

WA

TE

R T

RE

AT

ME

NT

SL

UD

GE

S

Rar

e E

arth

s

Zr,

Hf,

Ti,

Sn

Lar

ge

Volu

me

GE

OT

HE

RM

AL

EN

ER

GY

PR

OD

UC

TIO

N W

AS

TE

METAL MININGAND

PROCESSINGWASTES

RAE-104991

Figure ES-1. Lifetime risks to the CPG from the disposal of NORM.

ES-11

The collective health effects per year of exposure per year's generated waste are shown in Figure

ES-2. As seen in Figure ES-2, none of the health effects per one year of exposure to one year's

waste generation exceeds 0.006. Risk assessment results for the reuse of four diffuse NORM

waste sectors are shown in Figure ES-3. None of the health effects per year of exposure to one

year's reuse of NORM wastes exceeds 0.3.

Estimated dominant risks to workers at NORM storage and disposal sites, on-site individuals, and

members of the CPG are summarized in Table ES-2. For site workers, the dominant exposure

pathway is indoor radon inhalation to office workers. For office workers, the 50-year lifetime

risks from one year of radon inhalation are estimated to range from 1.0 x 10-2 from the

processing of rare earths to 2.8 x 10-8 for land repeatedly fertilized with phosphate fertilizers.

For exposure pathways other than radon inhalation, the dominant health risks result from direct

gamma exposure of disposal pile workers. Risks from direct gamma exposure are, in most cases,

smaller than risks from indoor radon inhalation.

Indoor exposure to radon gas by a person living on an abandoned NORM disposal site tends to

dominate risks from the three exposure pathways that were analyzed for the on-site individual.

The two NORM sectors where estimated risks from direct gamma radiation exceed those from

indoor radon, phosphate slag and coal ash, involve wastes with very low radon emanations.

Waste sites where a cover was assumed to be placed over the waste -- for the rare earths and

zirconium, hafnium, titanium, and tin subsets of metal mining and processing; water treatment;

and geothermal energy production wastes -- have much lower risks from direct gamma radiation

than from radon.

For members of the CPG, exposure pathways other than radon inhalation dominate risks for most

of the NORM sectors. Risks from indoor radon are larger only for the rare earths; Zr, Hf, Ti,

Sn; oil and gas production waste; uranium mining overburden; phosphogypsum waste; and

geothermal energy production sectors. The 70-year lifetime risks to the members of the CPG

from one year of exposure range from 1.3 x 10-4 from oil and gas production waste to 2.0 x 10-9

from Zr, Hf, Ti, Sn.

ES-12

1.00E-7

1.00E-6

1.00E-5

1.00E-4

1.00E-3

1.00E-2

HE

ALT

H E

FF

EC

TS

UR

AN

IUM

MIN

ING

OV

ER

BU

RD

EN

PH

OS

PH

OG

YP

SU

M W

AS

TE

S

PH

OS

PH

AT

E S

LA

G

PH

OS

PH

AT

E F

ER

TIL

IZE

RS

CO

AL

AS

H

OIL

& G

AS

SC

AL

E/S

LU

DG

E

WA

TE

R T

RE

AT

ME

NT

SL

UD

GE

S

Rar

e E

arth

s

Zr,

Hf,

Ti,

Sn

Lar

ge

Volu

me

GE

OT

HE

RM

AL

EN

ER

GY

PR

OD

UC

TIO

N W

AS

TE

METAL MININGAND

PROCESSINGWASTES

RAE-104993

Figure ES-2. Health effects to the general population from the generation of one year’s waste.

ES-13

RAE-104989

Figure ES-3. Health effects to the general population from one year’s reuse.

PH

OP

HO

GY

PS

UM

(AG

RIC

ULT

UR

E)

PH

OS

PH

AT

E S

LA

G(R

OA

DS

)

OIL

SC

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TE

EL

RE

CY

CL

ING

)

WA

TE

R T

RE

AT

ME

NT

SL

UD

GE

S (

FE

RT

ILIZ

ER

)

1.00E-4

1.00E-3

1.00E-2

1.00E-1

1.00E+0

1.00E+1

HE

ALT

H E

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AL

AS

H(B

UIL

DIN

G)

MIN

ER

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GW

AS

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(R

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)

Tab

le E

S-2.

Sum

mar

y of

dom

inan

t ri

sks

to in

divi

dual

s fr

om d

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sal o

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s.

Dis

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r R

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aO

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CP

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Exp

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ays

Exc

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Rad

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tion

Rad

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hala

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Ura

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Min

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rbur

den

2.7E

-05

4.7E

-04

1.0E

-04

2.0E

-03

3.0E

-05

3.4E

-06

Pho

spho

gyps

um W

aste

s2.

5E-0

51.

8E-0

49.

1E-0

57.

6E-0

42.

7E-0

51.

3E-0

6

Pho

spha

te S

lag

3.6E

-05

2.1E

-05

1.3E

-04

9.0E

-05

4.0E

-05

1.3E

-07

Pho

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rs5.

4E-0

92.

8E-0

81.

8E-0

81.

2E-0

76.

1E-0

92.

1E-1

0

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4.0E

-06

3.3E

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1.5E

-05

1.4E

-05

4.4E

-06

1.6E

-08

Oil

& G

as S

cale

/Slu

dge

1.1E

-04

7.2E

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4.1E

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3.1E

-03

1.3E

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3.1E

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Wat

er T

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--

Lan

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5E-0

73.

4E-0

62.

6E-0

81.

5E-0

58.

2E-0

91.

5E-0

8

Met

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- R

are

Ear

ths

- Z

r, H

f, T

i, S

n -

Lar

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olum

e

3.8E

-03

7.7E

-05

2.0E

-05

1.0E

-02

8.0E

-04

9.4E

-05

4.3E

-09

8.6E

-11

7.3E

-05

4.3E

-02

3.5E

-03

4.1E

-04

5.8E

-07

2.0E

-09

2.2E

-05

9.9E

-06

1.9E

-06

6.3E

-07

Geo

ther

mal

Ene

rgy

Pro

duct

ion

Was

te2.

0E-0

41.

9E-0

31.

7E-1

98.

1E-0

31.

2E-0

86.

6E-0

6

____

____

____

____

____

aT

he 5

0-ye

ar li

feti

me

risk

of

a fa

tal c

ance

r fr

om o

ne y

ear

of e

xpos

ure.

bT

he 7

0-ye

ar li

feti

me

risk

of

a fa

tal c

ance

r fr

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ne y

ear

of e

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Lif

etim

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can

be c

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d by

mul

tipl

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thes

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lues

by

70.7

565

year

s.

ES-14

ES-15

Estimated population health effects (e.g., cumulative health effects to persons living and working

off site) are summarized in Table ES-3. Both the health effects per site and the health effects

from one year's waste are given in the table.

The risk assessment results suggest that a relatively moderate number of health effects could

result from the disposal of diffuse NORM wastes. These results are based only on exposure to

one year's NORM waste generation, however. Should the lifetime risks and total inventory of

NORM waste accumulated to date be used instead, the total number of health effects would

increase significantly.

ES.4.2 Reuse

Selected radiation exposures to workers, on-site individuals, members of the critical population

group, and the general population from reuse of some diffuse NORM wastes were estimated.

The reuse scenarios were: use of phosphogypsum and water treatment sludges as fertilizer in

growing crops; use of phosphate slag and copper production slag in road construction; use of coal

ash in cement and concrete, and recycling steel equipment containing NORM-contaminated scale

from oil production.

Doses and risks to workers from reuse scenarios were estimated for the use of phosphogypsum

in agriculture and the use of water treatment sludges as fertilizer. The largest 50-year lifetime

risk to a worker at the reuse site is 1.0 x 10-6. Doses and risk to on-site individuals from reuse

were estimated for the use of phosphogypsum in agriculture and use of water treatment sludge

as fertilizers.

For the phosphogypsum, phosphate slag, coal ash, water treatment sludge, and mineral processing

sectors, reuse also results in doses and risks to individuals that could be considered as on-site

individuals, namely residents in buildings constructed of concrete that uses coal ash or on land

fertilized by phosphogypsum or water treatment sludge and frequent users of highways that use

phosphate slag and copper production slag as aggregate and roadbed. The risks to on-site

ES-16

Table ES-3. Summary of off-site population health effects from storage or disposal of diffuse NORM wastes.

Number of Health Effectsa

NORM Waste Sector From the Generic Site From One Year's Waste

Uranium Mining Overburden 6.4E-04 4.4E-04

Phosphogypsum Wastes 8.1E-04 7.8E-04

Phosphate Slag 1.0E-05 6.6E-07

Phosphate Fertilizers 2.5E-07 3.5E-06

Coal Ash 1.2E-04 5.7E-03

Oil & Gas Scale/Sludge 1.4E-04 3.0E-05

Water Treatment Sludges -- Landfill 2.0E-06 1.0E-06

Metal Mining and Processing Waste

- Rare Earths

- Zr, Hf, Ti, Sn

- Large Volume

2.5E-04

3.5E-04

4.8E-05

5.3E-05

1.6E-06

9.7E-04

Geothermal Energy ProductionWaste

1.1E-04 8.0E-06

____________________

a Number of excess fatal cancers (70-year lifetime risk) expected in the exposed populationas a result of one year of exposure.

ES-17

individuals from reuse scenarios analyzed for these five sectors range from 2.6 x 10-5 for reuse

of phosphate slag to 2.7 x 10-7 for reuse of phosphogypsum.

Doses and risks to the CPG were estimated for the phosphogypsum, oil and gas, and water

treatment NORM sectors. They are dominated by doses and risks from direct gamma radiation

for the phosphogypsum and water treatment sectors. The direct gamma radiation pathway was

not analyzed for reuse for the oil and gas sector. The lifetime risks from one year's exposure

range from 1.2 x 10-6 from the reuse of water treatment sludges to 8.3 x 10-8 from use of

phosphogypsum in agriculture.

Estimated population doses and health effects were calculated for use of phosphogypsum and

water treatment sludges in agriculture and for recycling steel from oil production. For the

agricultural applications they are dominated by the pathway involving river water contaminated

by surface runoff. This is also the pathway causing the largest doses and health effects to the

population from all the diffuse NORM storage and disposal scenarios. For those two sources,

population doses from one year of intake are 1.7 mrem/yr from use of phosphogypsum and 14

mrem/yr from use of water treatment sludges. There are 4.4 x 10-7 and 4.8 x 10-6 corresponding

health effects, respectively.

For the recycling of steel in oil production equipment, the population dose from one year's

inhalation of effluent from the steel mill is estimated to be 1.3 x 102 mrem/yr and there are

estimated to be 3.6 x 10-5 health effects.

Table ES-4 shows annual reuse rates and estimated population health effects from one year's

exposure to reuse of one year's recycled diffuse NORM waste. In both the disposal and the

reuse cases, the largest population risk comes from the coal ash sector.

In order to gain a clear understanding of both absolute and relative (to disposal) impacts on

public health of reuse of NORM wastes more sophisticated analyses are needed. The estimates

ES-18

Table ES-4. Summary of estimated cumulative health effects from one yearof exposure to one year's reuse of waste.

Waste SectorEstimated Annual

Reuse (MT)Health Effects FromOne Year's Reusea

Phosphogypsum (Agriculture) 2.2E+05 1.7E-03

Phosphate Slag (Roads) 1.3E+06b 2.6E-02

Coal Ash (Building) 1.2E+05 2.5E-01

Oil Scale (Steel Recycling) 1.2E+04 3.0E-04

Water Treatment Sludges (Fertilizer) 1.0E+05 1.6E-02

Mineral Processing Waste (Roads) 2.5E+06b 2.7E-03

____________________

a The number of excess fatal cancers (70-year lifetime risk) expected in the population asa result of one year of exposure.

b The amount stated is not necessarily representative of a year's reuse of waste.

ES-19

given in Tables ES-3 and ES-4 should only be considered preliminary evaluations of the potential

impacts.

ES.4.3 Summary

Given the uncertainties associated with the exposure pathway models, it is estimated that the

results of this risk assessment analysis are within a factor of three of results that might be

obtained by using more sophisticated computer codes. Uncertainties in the waste volumes,

radionuclide concentrations and other pathway-related parameters likely exceed a factor of three.

Accordingly, depending upon a specific input parameter or assumption, the results may reveal

a still greater degree of variability. Finally, it should be noted that changing a parameter does

not always yield proportional changes in estimates, since competing factors may nullify an

increase in a specific parameter.

Even with the uncertainties described above, the results imply that the number of potential health

effects may be significant enough to warrant additional evaluation of NORM waste generation

and disposal practices for some of the NORM waste sectors.

A-1

A. Introduction

1. THE ORIGINS AND DEFINITIONS OF NORM WASTES

Radioactive materials can be classified under two broad headings: man-made and naturally

occurring radioactive materials (NORM). Man-made radionuclides are produced by splitting

atoms in nuclear reactors or by bombarding atoms with subatomic particles in accelerators,

nuclear reactors, and other devices. Examples of man-made radionuclides include cobalt-60,

strontium-90, and cesium-137. Radionuclides in NORM include primordial radionuclides that

are naturally present in the rocks and minerals of the earth's crust and cosmogenic radionuclides

produced by interactions of cosmic nucleons with target atoms in the atmosphere and in the earth.

Example of cosmogenic radionuclides include carbon-14 and tritium (hydrogen-3). Materials

containing cosmogenic radionuclides also fall under the definition of NORM but natural

concentrations of nuclides generated by cosmic nucleons are small and present minimal risks.

NORM (naturally occurring radioactive material) consists primarily of material containing

potassium-40 and isotopes belonging to the primordial series. The principal primordial

radionuclides are isotopes of heavy elements belonging to the radioactive series headed by the

three long-lived isotopes uranium-238 (uranium series), uranium-235 (actinium series), and

thorium-232 (thorium series). These three decay series are shown in Figures A-1 to A-3. All

three of these series have numerous radionuclides in their decay chains before reaching a stable

end point, lead. At background concentrations, the naturally occurring radionuclides in the

uranium, actinium, and thorium series contribute about one-half of the natural background

external radiation, and over 80 percent of the background including radon, to which all humans

are continuously exposed.

The principal radionuclide of concern in NORM is radium-226, a member of the uranium series,

which is present in natural soils in concentrations of about 1 pCi/g. However, NORM

radioisotopes may be present in different materials in varying concentrations, and some NORM

A-2

Figure A-1. Uranium-238 decay series.

RAE - 104316

α

α

α

238 U4.5 bil y

234

24 d

234 Pa1.2 m

α

β

βTh

234 U240,000 y

α

230Th77,000 y

226 Ra1,600 y

222 Rn3.8 d

α214 Bi20 m β

214 Pb27 m β

218 Po3.1 m

α

214 Po162µ sec

α Biβ

210

5.0 d

210 Po140 d

206 PbSTABLE

210 Pb22 y β

A-3

Figure A-2. Thorium-232 decay series.

RAE - 104317

βα

α

α 212 Bi7m 61m

αβ

232 Th14 bil y

228 Ra5.8 y

228 Ac6.2 h

α

β

228 Th1.9 y

224 Ra3.7 d

α

220 Rn56 s

216 Po0.15 s

212 Pb11 h β

208 Tl3.1 m β

208 PbSTABLE

212 Po0.30 µs

64%

36%

A-4

Figure A-3. Uranium-235 (Actinium) decay series.

RAE - 104319

235 U710 mil y

231

26 hr

α

βTh

α

227 Th18 d

219Rn3.9 s

223 Ra12 d

α

α

231 Pa34,000 y

α

227

22 y

223 Fr21 m

215 Po1.8 ms

211 Pb36 m β

211 Bi2.2 m β

211 Po0.52 s

α

207 Pb

207 Tl4.8 m β

STABLE

β

98.8%

β

1.2%

α

α

α 99.68%

Ac

0.32%

A-5

wastes may have radium-226 concentrations that are much higher than 1 pCi/g, and may be as

high as hundreds of thousands of pCi/g.

The ultimate sources of the primordial radionuclides in the environment are the earth's crust and

its underlying mantle. Selective movement of some materials from the mantle to the crust,

usually resulting from fluid movement driven by temperature differences, has caused a

heterogeneous organization of the chemical elements in the crust. Redistribution has also

occurred as a result of weathering, sedimentation, and chemical interactions in the crust. As a

consequence of these processes, potassium-40 and the uranium and thorium series nuclides have

tended to concentrate in certain minerals and certain geologic formations. For example, uranium

in significantly elevated concentrations is associated with phosphate ores in three major locations

in the U.S.: southeastern Idaho and parts of neighboring states, central Florida, and central

Tennessee and northern Alabama. Radionuclides from the uranium and thorium series are also

associated in widely varying proportions in the crude oil and brine extracted from underground

petroleum reservoirs.

NORM wastes are the radioactive residues from the extraction, treatment, and purification of

minerals, petroleum products, or other substances obtained from parent materials that may contain

elevated concentrations of primordial radionuclides. They also include any radioactive material

made more accessible by the actions of man. Each year, hundreds of millions of metric tons of

NORM waste are generated from a wide variety of processes, ranging from uranium and

phosphate mining to municipal drinking water treatment. Processes that produce NORM wastes

analyzed in this study include uranium mining, phosphate and elemental phosphorus production,

phosphate fertilizer production, coal ash generation, oil and gas production, drinking water

treatment, metal mining and processing, and geothermal energy production. Primordial

radionuclides present in the parent materials can become concentrated in the wastes during

mining and beneficiation, mineral processing, oil and gas extraction, or various other processes.

This results in radionuclide concentrations in NORM wastes that are often orders of magnitude

higher than in the parent materials.

A-6

The exposure to individuals from NORM wastes occurs in three main ways. The first is

associated with the normal onsite disposal of the waste in piles or stacks. This type of disposal

can lead to groundwater contamination and to airborne releases of radioactive particulates and

radon. The second is from the improper use and/or disposal of these wastes, such as for soil

conditioning or fill dirt around homes. This can lead to build-up of radon gas in homes, direct

exposure to individuals located nearby, contamination of soil and the crops growing in that soil,

and groundwater contamination. The third way is the reuse of NORM-contaminated materials,

such as in concrete aggregate, which could lead to increased radiation risks to members of the

public in a variety of ways.

2. REGULATION OF NORM WASTES

Most radionuclides are regulated under the authority of the Atomic Energy Act (AEA). The

AEA, however, does not cover NORM unless that material is specifically designated as source

material, such as high grade uranium and thorium ore. Uranium and thorium mill tailings are

also regulated under the AEA. The Environmental Protection Agency (EPA) is gathering

information to determine if regulations are warranted to control the disposal of higher

concentration (above 2 nanocuries/gram) of NARM (naturally-occurring and accelerator-produced

radioactive materials) wastes under the authority of the Toxic Substances Control Act (TSCA)

(EPA88). NORM wastes are a subset of NARM. Diffuse NORM wastes generally have lower

concentrations of radionuclides; for them no federal regulations currently exist. Due to the large

volumes of diffuse NORM wastes that are generated each year, and the potential risk of

individual exposures associated with the improper use and disposal of these wastes, it is

appropriate for the EPA to consider developing controls on the use and disposal of diffuse

NORM wastes.

In September 1989, the EPA released a draft preliminary risk assessment characterizing

generation and disposal practices of diffuse NORM wastes. The draft risk assessment report was

prepared as an initial step in the development of acceptable standards governing the disposal and

reuse of NORM waste and material. A second draft was issued in May 1991. This report has

A-7

been widely circulated for peer review to interested parties. Comments on the draft report

indicated that there was a need to further review the data, assumptions, and models used in that

report, provide additional information on categories of diffuse NORM waste that were not

explicitly addressed, and perform a more detailed risk assessment. This report, prepared in

response to those recommendations, presents the results of further characterization efforts and an

updated preliminary risk analysis. Thus, as the title indicates, this risk assessment is still

considered to be preliminary. It is also very generic in nature. If the EPA decides to propose

any regulations, a much more detailed risk assessment and characterization of the waste will be

conducted and described in a Background Information Document accompanying the proposed

regulations. This preliminary risk assessment will not be used as the primary source of

information for developing such regulations.

3. SCOPE OF REPORT

In the following chapters, the major waste generating processes for eight NORM waste sectors

are described and the radioactivity concentrations and volumes of these wastes are estimated.

Current practices for the wastes and their possible beneficial use or disposal are also discussed.

The risk assessments that address several exposure pathways to site workers, onsite residents,

members of the critical population group (CPG), and the general population from reuse and

disposal are evaluated for each of the eight NORM waste sectors. The exposure pathways

considered include direct gamma radiation, dust inhalation, downwind dispersion of resuspended

particulates and radon, indoor radon inhalation, exposure from materials and processes that

involve reuse of NORM waste, and ingestion of contaminated water and foodstuffs. The

exposure scenarios evaluated for disposal and reuse of the materials generated by each NORM

sector are shown in Table A-1 and Table A-2, respectively. A brief description is given in the

next section. Chapter D.1 presents a complete discussion of the exposure scenarios. Finally,

Chapter C presents an overview of past and current practices involving NORM wastes.

Tab

le A

-1.

Ris

k as

sess

men

t ex

posu

re s

cena

rios

for

dif

fuse

NO

RM

sto

rage

and

dis

posa

l.

Met

al M

inin

g an

dP

roce

ssin

g W

aste

Exp

osur

e Sc

enar

io

Ura

nium

Min

ing

Ove

rbur

den

Pho

spho

gyps

umW

aste

sP

hosp

hate

Slag

Pho

spha

teF

erti

lizer

sC

oal

Ash

Oil

& G

asSc

ale/

Slud

ge

Wat

erT

reat

men

tSl

udge

s --

Lan

dfill

Rar

eE

arth

sZ

r, H

f,T

i, Sn

Lar

geV

olum

e

Geo

ther

mal

Ene

rgy

Pro

duct

ion

Was

te

Wor

ker

Dir

ect G

amm

a E

xpos

ure

Dus

t Inh

alat

ion

Indo

or R

adon

Inh

alat

ion

X X X

X X X

X X X

X X ---

X X X

X X X

X X X

X X X

X X X

X X X

X X X

On-

Site

Ind

ivid

ual

Dir

ect G

amm

a E

xpos

ure

Dus

t Inh

alat

ion

Indo

or R

adon

Inh

alat

ion

X X X

X X X

X X X

X X X

X X X

X X X

X X X

X X X

X X X

X X X

X X X

Mem

ber

of t

he C

PG

Dir

ect G

amm

a E

xpos

ure

Inha

lati

on o

f C

onta

min

ated

Dus

tD

ownw

ind

Exp

osur

e to

Rad

onN

OR

M in

Bui

ldin

g M

ater

ials

- G

amm

aN

OR

M in

Bui

ldin

g M

ater

ials

- R

adon

Inge

stio

n of

Dri

nkin

g W

ater

fro

m a

Con

tam

inat

ed W

ell

Inge

stio

n of

Foo

d C

onta

min

ated

by

Wel

l Wat

erIn

gest

ion

of F

ood

Con

tam

inat

ed b

y D

ust D

epos

itio

nIn

gest

ion

of F

ood

Gro

wn

on R

epea

tedl

y Fe

rtili

zed

Soil

Inha

lati

on o

f C

onta

min

ated

Dus

t f

rom

Ste

el M

ill S

tack

Rel

ease

s

X X X ---

--- X X X ---

---

X X X ---

--- X X X ---

---

X X X ---

--- X X X ---

---

X X X ---

--- X X X X ---

X X X ---

--- X X X ---

---

X X X ---

--- X X X ---

---

X X X ---

--- X X X ---

---

X X X ---

--- X X X ---

---

X X X ---

--- X X X ---

---

X X X ---

--- X X X ---

---

X X X ---

--- X X X ---

---

Gen

eral

Pop

ulat

ion

Nea

r D

ispo

sal S

ites

Dow

nwin

d E

xpos

ure

to R

esus

pend

ed P

artic

ulat

esD

ownw

ind

Exp

osur

e to

Rad

onIn

gest

ion

of R

iver

Wat

er C

onta

min

ated

Via

the

Gro

undw

ater

P

athw

ayIn

gest

ion

of R

iver

Wat

er C

onta

min

ated

by

Sur

face

Run

off

Inge

stio

n of

Foo

dstu

ffs

Gro

wn

on R

epea

tedl

y Fe

rtili

zed

Soil

Dow

nwin

d E

xpos

ure

from

Ste

el M

ill

Sta

ck R

elea

ses

X X X X ---

---

X X X X ---

---

X X X X ---

---

X X X X X ---

X X X X ---

---

X X X X ---

---

X X X X ---

---

X X X X ---

---

X X X X ---

---

X X X X ---

---

X X X X ---

---

A-8

Tab

le A

-2.

Ris

k as

sess

men

t ex

posu

re s

cena

rios

for

reu

se o

f di

ffus

e N

OR

M

Exp

osur

e Sc

enar

ioP

hosp

hogy

psum

(Agr

icul

ture

)P

hosp

hate

Sla

g(R

oads

)

Coa

l Ash

(Bui

ldin

gM

ater

ials

)

Oil

Scal

e(S

teel

Rec

yclin

g)

Wat

erT

reat

men

tSl

udge

s(F

erti

lizer

)

Min

eral

P

roce

ssin

g W

aste

(R

oads

)

Wor

ker

Dir

ect G

amm

a E

xpos

ure

Dus

t Inh

alat

ion

Ind

oor

Rad

on I

nhal

atio

n

X X ---

---

---

---

---

---

---

---

---

---

X X ---

---

---

---

On-

site

Ind

ivid

ual

Dir

ect G

amm

a E

xpos

ure

Dus

t Inh

alat

ion

Ind

oor

Rad

on I

nhal

atio

n

X X X

---

---

---

---

---

---

---

---

---

X X X

---

---

---

Mem

ber

of t

he C

PG

Dir

ect G

amm

a E

xpos

ure

Inh

alat

ion

of C

onta

min

ated

Dus

t D

ownw

ind

Exp

osur

e to

Rad

on N

OR

M in

Bui

ldin

g M

ater

ials

- G

amm

a N

OR

M in

Bui

ldin

g M

ater

ials

- R

adon

Ing

esti

on o

f D

rink

ing

Wat

er f

rom

a

Con

tam

inat

ed W

ell

Ing

esti

on o

f F

ood

Con

tam

inat

ed b

y

Wel

l Wat

er I

nges

tion

of

Foo

d C

onta

min

ated

by

D

ust D

epos

itio

ns I

nges

tion

of

Foo

d G

row

n on

Rep

eate

dly

Fer

tili

zed

Soi

l I

nhal

atio

n of

Con

tam

inat

ed D

ust

f

rom

Ste

el M

ill S

tack

Rel

ease

s

X X X ---

--- X X X X ---

X ---

---

---

---

---

---

---

---

---

---

---

--- X X ---

---

---

---

---

---

---

---

---

---

---

---

---

--- X

X X X ---

--- X X X X ---

X ---

---

---

---

---

---

---

---

---

Gen

eral

Pop

ulat

ion

Nea

r R

euse

Sit

es

D

ownw

ind

Exp

osur

e to

Res

uspe

nded

P

arti

cula

tes

D

ownw

ind

Exp

osur

e to

Rad

on

Inge

stio

n of

Riv

er W

ater

Con

tam

inat

ed V

ia

t

he G

roun

dwat

er P

athw

ay

Inge

stio

n of

Riv

er W

ater

C

onta

min

ated

by

Sur

face

Run

off

In

gest

ion

of F

oods

tuff

s G

row

n on

R

epea

tedl

y F

erti

lize

d S

oil

D

ownw

ind

Exp

osur

e fr

om S

teel

Mil

l

Sta

ck R

elea

ses

X X X X X ---

---

---

---

---

---

---

---

---

---

---

---

---

---

---

---

---

--- X

X X X X X ---

---

---

---

---

---

---

A-9

A-10

4. EXPOSURE SCENARIOS DESCRIPTION

Risks from exposure to NORM waste are evaluated for site workers, on site individuals, members

of the critical population group (CPG), and the general population. These exposed persons are

identified and described in the following paragraphs.

Site workers include disposal pile workers and office workers. The disposal pile worker is

assumed to be an adult employee who works 2,000 hours per year (40 hours per week for 50

weeks), and spends 80 percent of his time on the waste pile. It is assumed that the waste pile

generally is not covered or capped. The worker uses machinery such as a grader or bulldozer

that places him one meter above the pile surface and provides some shielding from direct gamma

radiation. Exposure pathways for the disposal pile worker include direct radiation and dust

inhalation. For direct radiation, a shielding factor of 0.75 (RAE93) is applied to account for

reduction in radiation dose rate due to shielding provided by the machinery used by the worker.

The office worker also works 2,000 hours per year in a building located at the disposal site some

time after the site is closed, and is assumed to be exposed to radon gas and radon progeny.

Since the major source of radon gas entering the office building is the long-lived radionuclide

radium-226 (half life of 1,600 years) the potential for indoor radon levels from the radium

persists for a long time after the disposal site is closed.

Three exposure pathways are evaluated for a person who is assumed to live on a site that was

formerly used for the disposal of diffuse NORM wastes. The exposure pathways analyzed for

this "onsite individual" are dust inhalation, indoor radon inhalation and direct exposure to external

gamma radiation. For indoor exposure to radon, the exposure fraction (i.e., the fraction of a year

that the person is exposed) is 0.75. For direct exposure to gamma radiation, the equivalent

outdoor exposure fraction is 0.5. This equivalent exposure fraction assumes that 25 percent of

the time is spent outdoors and the rest of the time is spent indoors where the exposure level is

one-third of that outdoors.

A-11

Several exposure pathways are evaluated for a member of the CPG. This person is assumed to

be an adult who lives in a house located 100 m from the disposal pile (EPA88). The person gets

all of its water from a well adjacent to the house. Fifty percent of this person's foodstuffs are

assumed to be grown on site. For the member of the CPG, the exposure pathways analyzed

include direct radiation, inhalation of contaminated dust, downwind exposure to radon, exposure

to NORM in building materials, ingestion of contaminated well water, ingestion of foodstuffs

contaminated by well water, ingestion of foodstuffs contaminated by dust deposition, and

ingestion of foodstuffs grown on repeatedly fertilized soils. For direct exposure to gamma

radiation, contaminated dust inhalation, and downwind exposure to radon, the equivalent outdoor

exposure fraction is 0.50. This equivalent exposure fraction takes account of the time spent

outside plus the time spent indoors at reduced exposure levels.

Several exposure pathways are evaluated for the general population residing near the disposal

sites. They include downwind exposure to resuspended particulates, downwind exposure to

radon, ingestion of river water contaminated by groundwater or by surface runoff, and ingestion

of foodstuffs grown on repeatedly fertilized soils. For the downwind exposure pathways, the

exposed population is assumed to reside within a radius of 80,000 m (50 mi) of the disposal site

(EPA89). For the ingestion pathways the exposed population is generally assumed to live within

a river water "use area" of approximately 1,000 square miles.

The above exposure scenarios are discussed in detail in Chapter D.1. The risk assessment

parameters based on the background information provided in Chapters B.1 through B.8 are

summarized in Chapter D.2. The risk assessment results are presented in Chapter D.3.

A-12

5. ORGANIZATION OF THE REPORT

This report presents a waste characterization and preliminary risk assessment for diffuse NORM

waste. Chapters B.1 through B.8 present the major NORM waste generating sectors and a

description of the processes that result in the generation of such wastes. The characterization

provides a description of the physical and radiological properties of the waste and annual waste

generation rates. Also reviewed are current industry or NORM sector practices regarding the use

and disposal of such wastes. An overview of past disposal practices and misuse of NORM waste

is provided in Chapter C. The risk assessment, presented in Chapters D.1 through D.3, focuses

on the health impact associated with the uncontrolled disposal and/or use of these wastes. The

risk assessment estimates are calculated to provide an insight into the potential health impact

associated with NORM waste, to determine whether a more rigorous analysis or more detailed

characterization is justified, and to help evaluate the need for future regulatory action. Chapters

E.1 and E.2 provides a summary and conclusions. Volume II consists of appendices containing

the tabulated results from the analysis.

A-R-1

A. REFERENCES

EPA88 U.S. Environmental Protection Agency, "Low-Level and NARM RadioactiveWastes, Draft Environmental Impact Statement for Proposed Rules, Volume 1,Background Information Document," EPA 520/1-87-012-1, June 1988.

EPA89 U.S. Environmental Protection Agency, "Background Information Document,Proposed NESHAPS for Radionuclides," Draft, SC&A, Inc. report prepared forthe U.S. EPA, EPA/520/1-89-006, February 1989.

RAE93 Rogers and Associates Engineering, "A Preliminary Risk Assessment ofManagement and Disposal Options for Oil Field Wastes and Piping Contaminatedwith NORM in the State of Louisiana," prepared for the U.S. EnvironmentalProtection Agency, Report RAE 9232/1-1R1, March 1993.

B-1-1

B.1 Uranium Mining Overburden

1.1 INTRODUCTION

The uranium mining industry began in the late 1940s primarily for the purpose of producing

uranium ore for use in weapons production and nuclear fuel fabrication. The mining of uraniu

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