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EPA/600/P-00/001Bd
September 2000
Draft Final
www.epa.gov/ncea
Exposure and Human Health Reassessment
of 2,3,7,8-Tetrachlorodibenzo-/?-Dioxin (TCDD)
and Related Compounds
Part I: Estimating Exposure to Dioxin-Like Compounds
Volume 4: Site-Specific Assessment Procedures
Exposure Assessment and Risk Characterization Group
National Center for Environmental Assessment - Washington Office
Office of Research and Development
U.S. Environmental Protection Agency
Washington, DC
DISCLAIMER
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This document is a draft. It has not been formally released by the U.S. Environmental
Protection Agency and should not at this stage be construed to represent Agency policy. Mention
of trade names or commercial products does not constitute endorsement or recommendation for
use.
ABSTRACT
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CONTENTS
1. INTRODUCTION 1-1
1.1. BACKGROUND 1-1
1.2. DESCRIPTION OF DIOXIN-LIKE COMPOUNDS 1-2
1.3. TOXICITY EQUIVALENCY FACTORS 1-3
1.4. OVERALL COMMENTS ON THE USE OF VOLUME IV OF THE DIOXIN
EXPOSURE DOCUMENT 1-6
1.5. NOTES ON THE USE OF PROCEDURES IN VOLUME IV 1-6
REFERENCES FOR CHAPTER 1 1-10
2. ESTIMATING EXPOSURES AND RISKS 2-1
2.1. INTRODUCTION 2-1
2.2. EXPOSURE EQUATION 2-2
2.3. CANCER AND NON-CANCER RISK ASSESSMENT 2-4
2.3.1. Cancer Risk Assessment 2-4
2.3.2. Evaluating Non-Cancer Effects 2-6
2.4. THE TOXIC EQUIVALENCY PROCEDURE 2-6
2.5. PROCEDURE FOR ESTIMATING EXPOSURE 2-7
2.6. STRATEGY FOR DEVISING EXPOSURE SCENARIOS 2-10
2.7. EXPOSURE PATHWAYS AND PARAMETERS 2-13
2.7.1. Soil Related Exposures 2-14
2.7.1.1. Soil Ingestion 2-14
2.7.1.2. Soil Dermal Contact 2-15
2.7.2. Vapor and Dust Inhalation 2-17
2.7.3. Water Ingestion 2-19
2.7.4. Ingestion of Terrestrial Food Products 2-19
2.7.4.1. Derivation of the Contact Fractions for Beef, Milk,
Chicken, Eggs, Vegetables, and Fruits 2-23
2.7.4.2. Beef Ingestion 2-24
2.7.4.3. Dairy Ingestion 2-25
2.7.4.4. Chicken Ingestion 2-25
2.7.4.5. Egg Ingestion 2-25
2.7.4.6. Vegetable and Fruit Ingestion 2-26
2.7.5. Fish Ingestion 2-26
REFERENCES FOR CHAPTER 2 2-29
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CONTENTS (continued)
3. EVALUATING ATMOSPHERIC RELEASES OF DIOXIN-LIKE COMPOUNDS
FROM COMBUSTION SOURCES 3-1
3.1. INTRODUCTION 3-1
3.2. ESTIMATING THE EMISSIONS OF DIOXIN-LIKE COMPOUNDS
FROM ANTHROPOGENIC COMBUSTION SOURCES 3-2
3.2.1. A Strategy for Generating Emission Factors 3-4
3.2.2. Use of Homologue and Congener-Specific Profiles to Estimate
Emission Factors 3-7
3.2.2.1 Using Congener Profiles to Convert Total CDD/F 3-8
3.2.2.2 Estimating Congener-Specific Emissions when no Congener
Profiles are Available 3-8
3.2.3. Estimation of Emissions of Dioxin-Like Compounds from the
Hypothetical Incinerator 3-9
3.2.4. Estimation of the Vapor Phase/Particle Phase Partitioning of Emissions
of Dioxin-Like Compounds 3-10
3.2.4.1. Vapor Phase/Particulate Phase Inferences from Stack
Measurements 3-10
3.2.4.2. Discussion of Vapor/Particle Ratios Derived from Stack
Testing Methods 3-13
3.2.4.3. Vapor/Particle Partitioning of CDD/Fs from Ambient Air
Sampling 3-16
3.2.4.4. Discussion of the Vapor/Particle Partitioning in Ambient
Air Sampling Studies 3-23
3.2.4.5. Junge-Pankow Model of Particle/Gas Distribution in
Ambient Air 3-23
3.2.4.6. Modeling the Vapor/Particle (V/P) Distribution of CDD/Fs . 3-26
3.2.4.7. Comparison of Measured and Modeled Vapor/Particle
Distributions for CDD/Fs 3-29
3.2.4.8. Discussion of Monitored and Modeled Results for CDD/Fs . 3-31
3.2.4.9. Discussion of Vapor/Particle Partitioning 3-33
3.2.5. Estimation of the Concentration of Dioxin-Like Compounds in
Incineration Ash 3-34
3.3. AIR DISPERSION/DEPOSITION MODELING OF THE STACK GAS
EMISSIONS OF DIOXIN-LIKE COMPOUNDS 3-36
3.3.1. Basic Physical Principles Used to Estimate Atmospheric
Dispersion/Deposition of Stack Emissions 3-37
3.3.2. Estimation of Dry Surface Deposition Flux 3-38
3.3.3. Estimation of the Particle Size Distribution in the Stack Emissions . . . 3-42
3.3.4. Estimation of Wet Deposition Flux 3-44
3.3.5. Using ISCST3 to Model Emissions of Particles and Vapors 3-46
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CONTENTS (continued)
3.4. RESULTS OF THE AIR DISPERSION MODELING OF CONGENER-
SPECIFIC EMISSIONS FROM THE HYPOTHETICAL ORGANIC
WASTE INCINERATOR 3-47
3.5. REVIEW OF PROCEDURES FOR ESTIMATING SITE-SPECIFIC
IMPACTS FROM A STACK EMISSION SOURCE 3-50
REFERENCES FOR CHAPTER 3 3-52
4. ESTIMATING EXPOSURE MEDIA CONCENTRATIONS 4-1
4.1. INTRODUCTION 4-1
4.2. BACKGROUND FOR SOLUTION ALGORITHMS 4-1
4.3. ALGORITHMS FOR THE SOIL CONTAMINATION SOURCE
CATEGORY 4-7
4.3.1. Surface Water and Sediment Contamination 4-8
4.3.2. Exposure Site Soil Concentrations 4-23
4.3.3. Vapor-and Particle-Phase Air Concentrations 4-31
4.3.4. Biota Concentrations 4-40
4.3.4.1. Fish Concentrations 4-40
4.3.4.2. Vegetation Concentrations 4-49
4.3.4.3. Beef and Milk Concentrations 4-68
4.3.4.4. Chicken and Egg Concentrations 4-78
4.3.5. Specific Cases of Soil Contamination 4-84
4.3.5.1. Landfills Receiving Ash from Municipal Waste
Incinerators 4-84
4.3.5.2. Land Application of Sludge from Pulp and Paper Mills 4-92
4.3.5.3. Sites Studied in the National Dioxin Study 4-94
4.4. ALGORITHMS FOR THE STACK EMISSION SOURCE CATEGORY . . . 4-97
4.4.1. Steady-State Soil Concentrations 4-98
4.4.2 Surface Water Impacts 4-100
4.5. ALGORITHMS FOR THE EFFLUENT DISCHARGE SOURCE
CATEGORY 4-105
4.5.1. The Simple Dilution Model 4-107
REFERENCES FOR CHAPTER 4 4-116
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CONTENTS (continued)
5. DEMONSTRATION OF METHODOLOGY 5-1
5.1. INTRODUCTION 5-1
5.2. STRATEGIES FOR DEVISING EXPOSURE SCENARIOS 5-2
5.3. EXAMPLE EXPOSURE SCENARIOS 5-8
5.4. EXAMPLE COMPOUNDS 5-12
5.5. SOURCE TERMS 5-13
5.6. RESULTS 5-19
5.6.1. Observations Concerning Exposure Media Concentrations 5-20
5.6.2. Observations Concerning LADD Exposure Estimates 5-27
5.7. HEALTH RISK DEMONSTRATIONS 5-30
REFERENCES FOR CHAPTER 5 5-31
6. USER CONSIDERATIONS 6-1
6.1. INTRODUCTION 6-1
6.2. CATEGORIZATION OF METHODOLOGY PARAMETERS 6-1
6.3. SENSITIVITY ANALYSIS 6-7
6.3.1. Limitations of the Sensitivity Analysis Exercises 6-7
6.3.2. Methodology Description and Parameter Assignments 6-10
6.3.3. Results 6-23
6.3.3.1. Estimation of Vapor-Phase and Particle-phase Air
Concentrations Distant from a Site of Soil Contamination . . . 6-23
6.3.3.2. Estimation of Soil Erosion Impacts to Nearby Sites of
Exposure 6-25
6.3.3.3. Estimation of Soil Erosion Impacts to Nearby Surface
Water Bodies 6-27
6.3.3.4. Vapor-Phase Transfers and Particle-Phase Depositions to
Above Ground Vegetation 6-29
6.3.3.5. Estimation of Below Ground Vegetation Concentrations ... 6-33
6.3.3.6. Beef Fat Concentration Estimation in the Soil Contamination
and Stack Emission Source Categories 6-34
6.3.3.7. Impact of Distance from the Stack Emission Source on
Concentrations in Soil, Vegetables, and Beef Fat 6-37
6.3.3.8. Water and Fish Concentrations Resulting from Effluent
Discharges 6-38
6.3.3.9. Water and Fish Concentrations Resulting from Stack
Emissions 6-39
6.3.4. Key Trends from the Sensitivity Analysis Testing 6-40
6.4. MASS BALANCE CONSIDERATIONS 6-42
REFERENCES FOR CHAPTER 6 6-48
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CONTENTS (continued)
7. MODEL COMPARISONS AND MODEL VALIDATIONS 7-1
7.1. INTRODUCTION 7-1
7.2. MODEL COMPARISON EXERCISES 7-3
7.2.1. Evaluation of Alternative Air-to-Leaf Modeling Approaches 7-3
7.2.1.1. The Field Data 7-4
7.2.1.2. Model Descriptions and Application to the Field Data 7-4
7.2.1.3. Results and Discussion of the Air-to-Leaf Model
Comparison Exercise 7-9
7.2.1.4. Literature Comparisons of Air-to-Plant Modeling
Approaches 7-14
7.2.2. An Alternate Modeling Approach for Estimating Water
Concentrations Given a Steady Input Load from Overland Sources ... 7-16
7.2.3. Estimating Fish Tissue Concentrations Based on Water Column
Concentrations Rather than Bottom Sediment Concentrations 7-19
7.2.4. Other Modeling Approaches and Considerations for Air
Concentrations Resulting from Soil Volatilization 7-24
7.2.5. Alternate Models for Estimating Plant Concentrations from Soil
Concentrations 7-37
7.2.6. Alternate Modeling Approaches for Estimating Beef and Milk
Concentrations 7-40
7.3. MODEL VALIDATION EXERCISES 7-50
7.3.1. The Impact ofDioxin Soil Contamination to Nearby Soils 7-50
7.3.2. Soil Concentrations and Concurrent Concentrations in Bottom
Sediments and Fish 7-52
7.3.3. Other Bottom Sediment Concentration Data 7-57
7.3.4. Data on Water Concentrations of Dioxin-Like Compounds 7-58
7.3.5. Data on Fish Concentrations in the Literature 7-59
7.3.6. Impact of Pulp and Paper Mill Effluent Discharges on Fish Tissue
Concentrations 7-63
7.3.7. Air Dispersion and Soil Concentration Modeling Around an
Incinerator Known to be Emitting Large Amounts of Dioxins 7-68
7.3.7.1. Modeling Procedures 7-70
7.3.7.2. Results and Discussions 7-77
7.3.7.3. Discussion and Concluding Remarks 7-83
7.3.8. Air-to-Soil and Soil-to-Air Modeling 7-85
7.3.9. Transfer of Dioxins From Soils to Below Ground Vegetables 7-89
7.3.10. Impacts of Contaminated Soils to Vegetation 7-90
7.3.11. Comparison ofMeasured and Modeled Vapor/Particle Distributions
for Semivolatile Compounds Other Than Dioxin 7-96
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CONTENTS (continued)
7.3.12. An Update of the Air-to-Beef Model Validation Exercise 7-98
7.3.13. Expansion of the Terrestrial Food Chain Model for Dioxins and
Applications to other Foodstuffs in the United Kingdom 7-109
7.3.14. Beef and Milk Fat Concentrations when Soil is the Source of
Contamination 7-110
REFERENCES FOR CHAPTER 7 7-112
8. UNCERTAINTY 8-1
8.1. INTRODUCTION 8-1
8.2. A DISCUSSION OF UNCERTAINTY ISSUES ASSOCIATED WITH THE
USE OF ISCST3 FOR TRANSPORT AND DISPERSION OF STACK
EMITTED CONTAMINANTS 8-3
8.3. UNCERTAINTIES AND VARIABILITIES WITH CHEMICAL-SPECIFIC
MODEL PARAMETERS AND ASSUMPTIONS 8-7
8.4. UNCERTAINTIES ASSOCIATED WITH EXPOSURE PATHWAYS 8-11
8.4.1. Lifetime, Body Weights, and Exposure Durations 8-12
8.4.2. Soil Ingestion Exposure 8-13
8.4.3. Soil Dermal Contact Pathway 8-16
8.4.4 Water Ingestion 8-18
8.4.5. Fish Ingestion Exposure 8-19
8.4.6. Vapor and Particle Phase Inhalation Exposures 8-22
8.4.7. Fruit and Vegetable Ingestion 8-26
8.4.8. Ingestion of Terrestrial Animal Food Products Including Beef, Milk,
Chicken, and Eggs 8-30
8.5. USE OF PROBABILISTIC TECHNIQUES FOR ASSESSING EXPOSURE
TO DIOXIN-LIKE COMPOUNDS 8-33
REFERENCES FOR CHAPTER 8 8-38
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TABLES
Table 1-1. The TEF scheme for I-TEQDF 1-12
Table 1-2. The TEF scheme for dioxin-like coplanar PCBs, as determined by the
World Health Organization in 1994 1-13
Table 1-3. The TEF scheme for TEQDFP-WH098 1-14
Table 2-1. Summary of exposure pathway parameters selected for the demonstration
scenarios of Chapter 5 2-32
Table 2-2. Percent weight losses from preparation of various meats 2-35
Table 3-1. The number of dioxin-like and total congeners within dioxin, furan, and
coplanar PCB homologue groups 3-61
Table 3-2. Emission factors and average emissions used for the hypothetical incinerator . 3-62
Table 3-3. Percent distribution of dioxins and furans between vapor-phase (V) and
particulate-phase (P) as interpreted by various stack sampling methods
(4-D = tetraCDD; 4-F = tetraCDF) 3-63
Table 3-4. Review of air monitoring data on the percentage of measured dioxins and
furans which are in the particle phase (4-D = tetraCDD; 4-F = tetraCDF) . . . 3-65
Table 3-5. Values of 0, Vx, and TSP in different air regimes 3-66
Table 3-6. Data for calculation of the liquid subcooled vapor pressure, p°L, at 20 °C, and
final p°L for the dioxin-like congeners 3-67
Table 3-7. Particle fractions, 4>, in four airsheds at 20°C for the dioxin-like congeners . . . 3-68
Table 3-8. Regression parameters slope m and intercept b for Equation (3-5),
Log Kp = m Log p°L + b, based on field measurements of particle/gas
distributions for CDD/Fs 3-69
Table 3-9. Comparison of monitored and modeled particulate percentage for CDD/F
homologues at 20°C 3-70
Table 3-10. Factors that influence the dry deposition removal rate in the atmosphere 3-71
Table 3-11. A summary of dry deposition velocities for particles 3-72
Table 3-12. Generalized particle size distribution (|im), and proportion of available
surface area, in particulate emissions from incineration 3-73
Table 3-13. Unit wet deposition scavenging coefficients per particle diameter category
(micrometers) used in the example ISCST3 analysis, expressed as
l/(sec-mm/hr) 3-74
Table 3-14. Emission of CDD/Fs (g/sec) from the hypothetical incinerator 3-75
Table 3-15. Modeling parameters used in the ISCST3 modeling of CDD/F emissions
from the hypothetical incinerator 3-76
Table 3-16. Predicted average vapor-phase concentrations of CDD/Fs (pg/m3; columns
are downwind distance in km) 3-77
Table 3-17. Predicted average particle-phase concentrations of CDD/Fs (pg/m3; columns
are downwind distance in km) 3-78
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TABLES (continued)
Table 3-18. Predicted annual dry deposition of particle-bound CDD/Fs (pg/m2-yr; columns
are downwind distance in km) 3-79
Table 3-19. Predicted annual wet deposition of particle-bound CDDs/Fs (pg/m2-yr;
columns are downwind distance in km) 3-80
Table 4-1. Available Biota to Sediment Accumulation Factors, BSAF, for dioxin-like
compounds 4-130
Table 4-2. Available Biota to Sediment Accumulation Factors, BSAF, for PCBs 4-135
Table 4-3. Data and parameters used to determine the part of the plant concentration
which was due to the deposition of particle bound dioxins (see below table
for definition of columns) 4-138
Table 4-4. Development of the Bvpa using data of Welsch-Pausch, et al (1995) compared
against the Bvpa as developed in EPA (1994) (see below table for column
definitions) 4-139
Table 4-5. Ratios of dioxins and furans in milk fat (MF) and body fat (BF) to
concentrations in diets of farm animals 4-140
Table 4-6. Ratios of PCBs in milk fat (MF) and body fat (BF) to concentrations in
diets of lactating cows 4-142
Table 4-7. BCFs for liver, adipose, thigh meat, and eggs calculated from the Cal-EPA
experiments 4-143
Table 4-8. Chicken and egg BCFs for Aroclor mixtures 4-144
Table 4-9. Ranges of concentrations of PCDDs, PCDFs, and PCBs in municipal waste
combustor ash (results in ng/g or ppb; ND = Not detected; NR = not reported;
Tr = trace; DL between 0.01 and 0.1 ng/g) 4-145
Table 5-1. Fate and transport parameters for the dioxin-like congeners demonstrated in
this chapter 5-33
Table 5-2. Summary of key source terms for the background scenarios, 1 and 2 5-35
Table 5-3. Summary of key source terms for Scenarios 4 and 5, the stack emission
demonstration scenarios 5-36
Table 5-4. WH098-TEQDF environmental and exposure media concentrations for the
background conditions scenarios, #1 and #2, and the stack emissions
demonstration scenarios, #4 and #5 5-37
Table 5-5. Environmental and exposure media concentrations for 2,3,7,8-TCDD
("dioxin"), 2,3,4,7,8-PCDF ("furan") and 2,3,3',4,4',5,5'-HPCB (PCB) for
the soil contamination demonstration, scenario #3, and the effluent discharge
demonstration, scenario #6 (NA = not applicable) 5-38
Table 5-6. Individual congener and Toxic Equivalent (WH098-TEQDF) concentrations for
predicted beef concentration for the background high scenario, scenario # 2,
and the stack emission high scenario, scenario 5 5-39
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TABLES (continued)
Table 5-7. Lifetime average daily doses, LADD, of Toxic Equivalents (TEQs), for the
background scenarios, #1 and #2, and for the stack emission scenarios, #4
and #5 5-40
Table 5-8. Lifetime average daily doses, LADD, for 2,3,7,8-TCDD ("dioxin"),
2,3,4,7,8-PCDF ("furan") and 2,3,3',4,4',5,5'-HPCB (PCB) for the soil
contamination demonstration, scenario #3, and the effluent discharge
demonstration, scenario #6 5-42
Table 5-9. Lifetime Average Daily Doses, LADD, of Toxic Equivalents (WH098-TEQDF)
for exposure pathways evaluated outside of the scenarios for background
conditions and stack emissions 5-43
Table 5-10. Lifetime Average Daily Doses, LADD, of 2,3,7,8-TCDD ("dioxin"),
2,3,4,7,8-PCDF ("furan") and 2,3,3',4,4',5,5'-HPCB ("PCB") for exposure
pathways evaluated outside of the scenarios for the soil contamination and
the effluent discharge settings 5-44
Table 5-11. Relative magnitude of all exposure pathways evaluated for the background
setting and the stack emission, high exposure scenario setting (see table
bottom for notes) 5-45
Table 6-1. Parameters used to estimate exposure media concentrations for this
assessment 6-51
Table 6-2. Contribution of above ground vegetation concentrations of 2,3,7,8-TCDD
from air-to-leaf transfers and particulate depositions 6-59
Table 7-1. Observed data for the air-to-plant model comparison exercise 7-123
Table 7-2. Model results comparing the EPA vapor transfer model and the Vapor
Deposition Model with the field data for 2,3,7,8-TCDD 7-124
Table 7-3. Model parameters used in the Hwang and the alternate volatilization models
tested in this comparison exercise 7-125
Table 7-4. Results of model volatilization comparison exercise 7-126
Table 7-5. Summary of off-site soil contamination from Tier 1 and 2 sites of the
National Dioxin Study 7-127
Table 7-6. Description of soil, sediment, and fish sampling program of dioxin-like
compounds undertaken by the Connecticut Department of Environmental
Protection 7-128
Table 7-7. Frequency of non-detects and detection limits for soil, sediment, and fish,
for three congeners in the Connecticut Department of Environmental
Protection data set 7-132
Table 7-8. Results for Connecticut Department of Environmental Protection sampling,
including soil, sediment and fish concentrations, and the key concentration
ratios of sediment to soil and the Biota Sediment Accumulation Factor
(BSAF) ratio 7-133
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TABLES (continued)
Table 7-9. Model parameters and results for effluent discharge model validation
testing 7-136
Table 7-10. ISCST3 and soil model input assumptions and parameters 7-142
Table 7-11 Comparison of observed and modeled total CDD/F concentration increments
at the urban monitoring stations 7-143
Table 7-12. Comparison of observed and modeled homologue and TEQ concentrations
at station SE-3 using on-site meteorological data for model input 7-144
Table 7-13. Results of ISCST3 deposition and soil prediction modeling, comparing
measured concentrations for clusters of soil samples with modeled
concentrations assuming either the 1992 or the 1994 stack tests 7-145
Table 7-14. Results of the air-to-soil and soil-to-air model testing 7-146
Table 7-15. Data and results of the soil to below ground vegetable validation exercise . . . 7-147
Table 7-16. Summary of plant concentration versus soil concentration data for
2,3,7,8-TCDD 7-148
Table 7-17. Parameters for the empirical relationship relating the sub-cooled liquid
vapor pressure, p°L, to the particle/gas partition coefficient, Kp, of
semivolatile organic compounds (SOC) 7-152
Table 7-18. Summary of modeling changes from the 1994 air-to-beef model validation
exercise to the present update 7-153
Table 7-19. Comparison of air concentration profiles used in the 1994 air-to-beef model
validation compared against the current air profiles 7-154
Table 7-20. Comparison of predicted leafy vegetation samples of the current, revised
validation exercise with the previous predictions of leafy vegetations and
several observations in the literature (units are pg/g dry weight) 7-155
Table 7-21. Results of the 1994 air-to-beef model validation exercise compared against
results from the current air-to-beef model validation exercises 7-156
Table 8-1. Uncertainties associated with the lifetime, body weight, and exposure
duration parameters 8-42
Table 8-2. Uncertainties associated with the soil ingestion pathway 8-43
Table 8-3. Uncertainties associated with the dermal exposure pathway 8-44
Table 8-4. Uncertainties associated with the water ingestion pathway 8-45
Table 8-5. Uncertainties associated with the fish ingestion pathway 8-46
Table 8-6. Uncertainties and sensitivities associated with estimating vapor and
particle-phase air concentrations from contaminated soils 8-47
Table 8-7. Uncertainties associated with vegetable/ fruit ingestion exposure algorithms . . 8-49
Table 8-8. Uncertainties associated with the terrestrial animal food pathways 8-50
Table 8-9. Distributions for a Monte Carlo exercise which developed soil cleanup
levels at residential and industrial sites 8-51
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TABLES (continued)
Table 8-10. Summary of Monte Carlo distributions used in a fish consumption
assessment 8-52
Table 8-11. Summary of Monte Carlo distributions used in food chain study 8-53
Table 8-12. Summary of parameter distributions used for modeling terrestrial fruits and
vegetables for human consumption in a Monte Carlo exercise 8-54
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FIGURES
Figure 1-1. Chemical structure of 2,3,7,8-TCDD and related compounds 1-15
Figure 3-1. Example of a congener and a homologue profile from a sewage sludge
incinerator 3-81
Figure 3-2. The relationships between the log of liquid sub-cooled vapor pressure, pL°,0
and the particle-gas partition coefficient, Kp, (figure (a)), and between pL°
and modeled (as indicated by "J-P" in figure (b)) and measured percent
particulate-phase in the ambient air (measurements from Eitzer &
Hites (1989)) 3-82
Figure 3-3. Comparison of measured particulate percentages of PCDD/F on a homolog
basis to predictions of the Junge-Pankow model as a function of the
sub-cooled liquid vapor pressure, p°L, of the homolog groups 3-83
Figure 4-1. Diagram of the fate, transport, and transfer relationships for the
soil contamination source category 4-146
Figure 4-2. Diagram of the fate, transport, and transfer relationships for the stack
emission source category 4-147
Figure 4-3. Diagram of the fate, transport, and transfer relationships for the effluent
discharge source category 4-148
Figure 4-4. Watershed delivery ratio, SDW, as a function of watershed size 4-149
Figure 6-1. Results of sensitivity analysis of algorithms estimating exposure site vapor
phase air concentrations resulting from a distant contaminated soil site 6-60
Figure 6-2. Results of sensitivity analysis of algorithms estimating exposure site particle
phase air concentrations resulting from a distant contaminated soil site 6-61
Figure 6-3. Results of sensitivity analysis of algorithms estimating exposure site soil
concentrations resulting from erosion from a site of soil contamination 6-62
Figure 6-4. Results of sensitivity analysis of algorithms estimating surface water impacts,
including sediment, water, and fish concentrations, resulting from a site of
soil contamination 6-63
Figure 6-5. Results of sensitivity analysis of algorithms estimate above ground
vegetation concentrations due to vapor phase transfers 6-64
Figure 6-6. Results of sensitivity of algorithms estimating above ground vegetation
concentrations from deposition of particle-bound dioxins 6-65
Figure 6-7. Impact of vapor/particle partitioning on vegetation concentrations in the
stack emission source category 6-66
Figure 6-8. Results of sensitivity analysis of algorithms estimating below ground
vegetable concentrations in the soil contamination source category 6-67
Figure 6-9. Results of sensitivity analysis of algorithms estimating beef fat
concentrations in the soil contamination source category 6-68
Figure 6-10. Results of sensitivity analysis of algorithms estimating beef fat
concentrations in the stack emission source category 6-69
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FIGURES (continued)
Figure 6-11. Impact of distance from the stack emission source to soil, vegetable, and
beef fat concentrations 6-70
Figure 6-12. Results of sensitivity analysis of algorithms estimating surface water
and fish concentrations resulting from effluent discharges 6-71
Figure 6-13. Results of sensitivity analysis of algorithms estimating surface water
and fish concentrations resulting from stack emissions 6-72
Figure 7-1. Comparison of observed and predicted grass concentrations of dioxin and
furan congeners for the EPA and the scavenging models at the rural site. ... 7-157
Figure 7-2. Comparison of observed and predicted grass concentrations of dioxin and
furan congeners for the EPA and the scavenging models at the industrial site. 7-158
Figure 7-3. The observed scavenging coefficient (grass concentration over air
concentration) calculated from the rural site data 7-159
Figure 7-4. Comparison of observed and predicted deposition at the rural and industrial
sites 7-160
Figure 7-5. Schematic of effluent discharge model showing all parameter inputs and
observed fish concentrations 7-161
Figure 7-6. Comparison of predicted and observed fish tissue concentrations for validation
of the effluent discharge model 7-162
Figure 7-7. Site map showing locations of soil and air samples in the vicinity of the
Columbus Municipal Solid Waste-To-Energy (CMWSTE, abbreviated WTE
above) Facility 7-163
Figure 7-8. Isoline figures of predicted air concentrations overlain by measured air
concentrations of TCDD, OCDD, and TEQ (pg/m3) when using the "on-site"
meteorological data set (sub-figures a, b, and c) and when using the "airport"
meteorological data set (sub-figures d, e, and f) 7-164
Figure 7-9. Isoline figures of predicted soil concentrations of TCDD, OCDD, and TEQ
(sub-figures a, d, g) compared against isoline figures of measured soil
concentrations using the 1992 stack emission test (sub-figures b, e, and h)
and the 1994 stack emission test (sub-figures c, f, and i) 7-166
Figure 7-10. Comparison of measured and predicted particulate percentages of PAHs in
urban and rural air 7-167
Figure 7-11. Comparison of measured and predicted particulate percentages of PCBs and
organochlorine pesticides in urban and rural air 7-168
Figure 7-12. Overview of model to predict beef concentrations from air concentrations . . 7-169
IV-xv
September 2000
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