&EPA
United States
Environmental Protection
Agency
EPA/600/R-17/027 I February 2017
www.epa.gov/homeland-security-research
Exposure Assessment of Livestock
Carcass Management Options During
Natural Disasters
Office of Research and Development
Homeland Security Research Program
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EPA/600/R-17/027
February 2017
Exposure Assessment of Livestock Carcass
Management Options During
Natural Disasters
U.S. Environmental Protection Agency
Office of Research and Development
National Homeland Security Research Center
Cincinnati, Ohio 45268
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
Disclaimer
The U.S. Department of Homeland Security, in collaboration with the U.S. Environmental
Protection Agency (EPA) and the U.S. Department of Agriculture, funded and managed the
research described herein under Interagency Agreement RW7095854501 and contract EP-C-14-
01 WA-24 to ICF International. It has been subjected to the Agency's review and has been
approved for publication. Numeric results in this assessment should not be interpreted as "actual"
risks. Note that approval does not signify that the contents necessarily reflect the views of EPA.
Mention of trade names, products, or services does not convey official EPA approval,
endorsement, or recommendation.
Questions concerning this document or its application should be addressed to:
Sandip Chattopadhyay, Ph.D.
National Homeland Security Research Center
Office of Research and Development
U.S. Environmental Protection Agency
26 West Martin Luther King Drive, NG-16
Cincinnati, Ohio 45268
(513)569-7549
Chattopadhyay. Sandip@epa. gov
Sarah C. Taft, Ph.D.
National Homeland Security Research Center
Office of Research and Development
U.S. Environmental Protection Agency
26 West Martin Luther King Drive, NG-16
Cincinnati, Ohio 45268
(513)569-7037
T aft. Sarah@epa. gov
111
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
Tat
Disclaimer iii
List of Tables vii
List of Figures x
Acknowledgements xi
Executive Summary xii
Acronyms and Abbreviations xvii
1. Introduction 1
1.1. Purpose and Scope 1
1.2. Report Organization 2
1.3. Unit Conventions 3
2. Problem Formulation 4
2.1. Livestock Carcass Management Options 5
2.2. Standardized Conditions 7
2.3. Site Setting and Environmental Conditions 8
1.1.1. Site Location and Meteorology 8
2.3.3. Soils, Crops, and Grazing Lands 11
2.3.4. Lake and Aquatic Food Web 11
2.3.5. Groundwater Well 12
1.4. Hazardous Agents 12
1.4.1. Chemical Agents 13
2.3.6. Microbes 19
1.5. Expert Workshop at the 5th International Symposium on Animal Mortality
Management 23
3. Conceptual Models of Carcass Management Options 26
3.1. Carcass Transportation and Handling 27
1.5.1. Carcass Handling Before and after Transportation 28
1.5.2. Temporary Carcass Storage Before Transportation 30
1.5.3. Carcass Transportation 32
3.2. On-site Open Burning (Pyre) 37
1.5.1. Releases of Combustion Products to Air 38
1.5.2. Leaching from Remaining Open-Burning Ash 43
3.3. On-site Air-curtain Burning 46
1.5.1. Releases of Combustion Products to Air 50
1.5.2. Leaching from Combustion Ash 52
3.4. On-site Burial 54
1.5.1. Leaching from Buried Carcasses 57
1.5.2. Methane Seepage from Buried Carcasses 60
3.5. Composting 63
1.5.1. Leaching to Groundwater 65
1.5.2. Releases to Air from the Windrow 67
1.5.3. Application of Compost to Soil 67
4. Chemical Fate and Transport 72
4.1. Air 73
4.2. Surface Soil 80
IV
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
4.3. Groundwater 83
1.5.1. Leaching from Buried Carcasses 83
1.5.2. Leaching from Buried Combustion Bottom-Ash 85
1.5.3. Leaching from the Compost Windrow 88
1.5.4. Leaching from the Storage Pile 88
1.5.5. Interception of Groundwater By Well 89
4.4. Surface Waters and Sediment 95
4.5. Bioaccumulation in Fish 98
1.1. Terrestrial Plants and Livestock 100
1.1.1. Terrestrial Plants 103
1.1.2. Livestock 103
5. Exposure Estimation for Chemicals 105
5.1. Summary of Chemical Exposure Pathways for Humans 105
5.2. Characterization of Exposed Individuals 109
1.1.1. Description of Exposed Persons 110
1.1.2. Exposure Durations 110
1.1.3. Human Exposure Factor Values Ill
5.3. Exposure Estimation 113
1.1.1. Inhalation 113
1.1.2. Ingestion Media 114
5.4. Livestock and Environmental Exposures 125
1.1.1. Livestock Exposure 125
1.1.2. Environmental Exposure 128
6. Exposure Estimation for Microbes 133
6.1. Summary of Human Exposure Pathways for Microbes 139
1.2. Estimated Human Ingestion Exposures 146
1.2.1. Estimated Ingestion 153
1.2.2. Conclusions 154
6.2. Livestock and Environmental Exposures 155
1.2.1. Livestock Exposure 155
6.2.3. Wildlife Exposure 162
7. Comparative Risks for Livestock Management Options 166
7.1. Tier 1 Comparison of the Seven Carcass Management Options 166
7.2. Tier 2 Ranking of On-site Carcass Management Options 168
1.2.1. Tier 2 Ranking Based on Chemical Exposures 168
7.2.3. Tier 2 Ranking for Microbial Exposures 186
7.3. Conclusions and Discussion of Uncertainty 192
1.2.1. Conclusions 193
1.2.2. Uncertainties 196
7.4. Summary of Findings, Mitigation Measures, and Research Needs 202
8. Quality Assurance 209
9. Literature Cited 211
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
TABLE OF CONTENTS FOR APPENDICES App. - i
Appendix A. Data for Polycyclic Aromatic Hydrocarbons A-l
Appendix B. Data for Dioxins and Furans B-l
Appendix C. Conceptual Models C-l
Appendix D. AERMOD Supporting Information D-l
Appendix E. Description of the HHRAP Soil and Surface Water (SSW) Screening
Model E-l
Appendix F, Detailed Parameter Documentation Tables for the HHRAP SSW
Excel™ Model F-l
Appendix G. Supporting Information for Chemical Leaching from Burial,
Composting, and Carcass Storage G-l
Appendix H, Supporting Information for Chemical Leaching from Combustion Ash H-l
Appendix I. Supporting Information for Groundwater Recharge to Surface Water 1-1
Appendix J. Aquatic Food Web Modeling J-l
Appendix K. Documentation of the Multimedia Ingestion Risk Calculator K-l
Appendix L. Toxicity Reference Values L-l
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
List of Tables
Table 2.1.1. Livestock Carcass Management Options Considered for the Exposure
Assessment 5
Table 2.1.2. Containment of Releases from Management Options 6
Table 2.2.1. Standardized Conditions and Assumptions 9
Table 2.4.1. Chemicals/Agents Retained for Exposure Assessment for Management
Options 15
Table 2.4.2. Justifications to Eliminate Chemicals or Their Exposure Sources or
Durations from Exposure Assessment for Carcass Management Options 16
Table 2.4.3. Chemical Hazards Possibly Associated with each Management Option 19
Table 2.4.4. Microbial Hazards Possibly Associated with Each Option 21
Table 3.1.1. Summary of Assumptions for Livestock Carcass Transportation and
Handling 28
Table 3.2.1. Source and Exposure Pathway Assumptions for On-site Open Burning
Management Option 39
Table 3.2.2. Emission Factors for PAHs from HOWI Incinerator Carcass Burning (mg/kg
carcass)3 40
Table 3.2.3. Emission Factors for Metals from HOWI Hog Carcass Incineration (mg/kg
carcass) 40
Table 3.2.4. Fuel Mass Used for Open-Pyre Burning and Quantity of Ash Remaining 41
Table 3.2.5. Emission Factors to Air for Open-Pyre Burning by Material Burned (weight
chemical/weight material burned)3 42
Table 3.2.6. Estimated Concentration of Chemicals Remaining in Bottom Ash from Open
Burning 44
Table 3.3.1. Assumptions for On-site Air-curtain Burning of Livestock Carcasses 49
Table 3.3.2. Emission Factors for PAHs from LIWI Incinerator Carcass Burning (mg/kg
waste)3 51
Table 3.3.3. Emission Factors for Metals from LIWI Animal Carcass Incineration (mg/kg
waste) 51
Table 3.3.4. Quantity of Ash from Air-curtain Burning 52
Table 3.3.5. Estimated Concentration of Chemicals in Ash from Air-curtain Burning 53
Table 3.4.1. Assumptions for the On-site Burial of Livestock Carcasses 56
Table 3.4.2. On-site Burial Release Characterization 58
Table 3.4.3. Potential Annual Releases (kg) of Chemicals from 1,000 kg Buried
Livestock3 58
Table 3.4.4. Average Two-year Leachate Concentrations (mg[chemical]/L[leachate]) by
Livestock Category (Pratt and Fonstad 2009) 59
Table 3.4.5. Estimated Concentration of Elements in Accumulating Leachate from Cattle
(pit no. 4) 61
Table 3.5.1. Assumptions for the Composting Management Option 65
Table 3.5.2. Change in Chemical Concentrations Pre- and Post-Composting Cattle
Carcasses using Corn Stalks (Glanville et al. 2006) 66
Table 3.5.3. Nutrient Content of the Cattle Carcass Compost (Kube 2002 as cited in
NABCC 2004) 68
Table 3.5.4. Nutrient Content of Hog Carcass Compost (McGahan 2002 as cited in
NABCC 2004) 68
Table 3.5.5. Nitrogen Requirements for Forage Grasses in Iowa (IAWEA 2011) 68
Table 3.5.6. Estimated Loading of Metals to Soil with Compost Application 71
Table 4.1.1. Parameterization of Combustion Units in AERMOD 74
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
Table 4.1.2. Land Cover Surrounding Hypothetical Farm, with Percent Area Covered 75
Table 4.1.3. Seasons at the Hypothetical Farm 75
Table 4.1.4. Summary of Precipitation Data for Iowa City Used in This Assessment 76
Table 4.2.1 Estimated Chemical Deposition from Air to Soil and Final Soil
Concentrations for Combustion-based Management Options 82
Table 4.2.2 Estimated Chemical Loading and Final Soil Concentrations for the
Composting Management Option 82
Table 4.3.1. Summary of Calculations for Groundwater Well Intercept Fraction 91
Table 4.3.2. Estimated Concentrations of Chemicals Leaching from Buried Carcasses
That Might Reach On-siteDrinking Water Well 92
Table 4.3.3. Estimated Concentrations of Chemicals Leaching from Buried Ash That
Might Reach On-site Drinking Water Well 93
Table 4.3.4. Estimated Concentrations of Chemicals in Leachate fom a Carcass Storage
Pile or a Composting Windrow that Might Reach On-site Drinking Water
Well from Compost and Storage Pile 94
Table 4.4.1 Estimated Total Concentrations of Chemicals in Surface Water 97
Table 4.4.2. Effect of Lake Size on Estimated Concentrations of Chemicals in Surface
Water - Burial Option 98
Table 4.5.1. Estimated Chemical Concentrations in Fish from the On-site Lake 101
Table 4.6.1. Chemical Transfer Pathways for Produce 103
Table 4.6.2. Chemical Transfer Pathways for Livestock 104
Table 5.2.1. Typical and High-end Exposure Factor Values For Infant Water
Consumption 113
Table 5.3.1. Inhalation Exposure Concentrations Open Burning and Air-curtain Burning 115
Table 5.3.2. Ingestion Exposure Estimates for Temporary Carcass Storage - Adults 119
Table 5.3.3. Ingestion Exposure Estimates for Temporary Carcass Storage - Children 1 to
<2 Years Old 119
Table 5.3.4. Ingestion Exposure Estimates for Open Burning - Adults 120
Table 5.3.5. Ingestion Exposure Estimates for Open Burning - Children 1 to <2 Years
Old 120
Table 5.3.6. Ingestion Exposure Estimates for Air-curtain Burning - Adults 121
Table 5.3.7. Ingestion Exposure Estimates for Air-curtain Burning - Children 1 to <2
Years Old 121
Table 5.3.8. Ingestion Exposure Estimates for Burial - Adults 122
Table 5.3.9. Ingestion Exposure Estimates for Burial - Children 1 to <2 Years Old 122
Table 5.3.10. Ingestion Exposure Estimates for Compost Windrow - Adults 123
Table 5.3.11. Ingestion Exposure Estimates for Compost Windrow - Children 1 to <2
Years Old 123
Table 5.3.12. Ingestion Exposure Estimates for Compost Application - Adults 124
Table 5.3.13. Ingestion Exposure Estimates for Compost Application - Children 1 to <2
Years Old 124
Table 5.3.14. Ingestion Estimates for Infants with Formula Made Using Well Water3 125
Table 5.4.1 Exposure Pathways and Routes for Livestock Carcass Management Options 126
Table 5.4.2. Chemical Concentrations in Beef, Pork, and Poultry After Carcass
Management by Open Burning (550°C) 126
Table 5.4.3. Chemical Concentrations in Beef, Pork, and Poultry After Carcass
Management by Air-Curtain Burning (850°C) 127
Table 5.4.4 Estimated Surface Soil Concentrations Compared with Ecological Soil
Screening Levels 129
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
Table 5.4.5. Chemical Concentrations in Surface Water compared to National Ambient
Water Quality Criteria for Aquatic Life - Criterion Continuous
Concentration (CCC) (i.e., for chronic exposures) 131
Table 6.1.1. Evaluation Factors Included in the Exposure Assessment for Microbes 137
Table 6.1.2. Human Exposure Pathways for Livestock Carcass Management Options -
Microbes 140
Table 6.2.1. Quantitative Assumptions for the Groundwater Exposure Pathway for
Microbes 150
Table 6.2.2. Concentration of Pathogens in Groundwater over Time (particles/m3) 151
Table 6.2.3. Estimated Human Ingestion of Microbes from a Groundwater Well
(particles/time interval) 153
Table 6.3.1. Livestock Exposure Pathways for Livestock Carcass Management Options -
Microbes 157
Table 6.3.2 Estimated Ingestion of Microbes from a Groundwater Well - Dairy Cattle
(particles/time interval) 161
Table 6.3.3 Estimated Ingestion of Microbes from a Groundwater Well - Beef Cattle
(particles/time interval) 161
Table 7.1.1. Tier 1 Ranking of Livestock Carcass Management Options 167
Table 7.2.1. Human Exposure Pathways for Livestock Carcass Management - Chemicals 169
Table 7.2.2. Ingestion Exposure Assessment for Temporary (48-hr) Carcass Storage 172
Table 7.2.3. Inhalation Exposure Assessment for the Open-burning Option 173
Table 7.2.4. Ingestion Exposure Assessment for the Open-burning Option 173
Table 7.2.5. Inhalation Exposure Assessment for the Air-curtain Burning Option 174
Table 7.2.6. Ingestion Exposure Assessment for the Air-curtain Burning Option 174
Table 7.2.7. Ingestion Exposure Assessment for the Burial Option 175
Table 7.2.8. Ingestion Exposure Assessment for the Composting Option 176
Table 7.2.9. Ingestion Exposure Assessment for the Composting Option - Windrow Only 177
Table 7.2.10. Ingestion Exposure Assessment for the Composting Option - Soil
Amended with Finished Compost 177
Table 7.2.11 Ingestion Ranking Ratios for Infants with Formula Made Using Well Water3 180
Table 7.2.12. Chemical Ranking Ratio Summary 182
Table 7.2.13. Potential Human Exposure Pathways and Routes for Livestock Carcass
Transportation and Handling Activities and Management Options -
Microbes 187
Table 7.2.14. Ingestion Exposure Assessment for Microbes 188
Table 7.3.1. Ranking of Livestock Carcass Management Options for Chemicals 194
Table 7.3.2. Tier 1 Ranking of Off-site Livestock Carcass Management Options for
Microbes 195
Table 7.3.3. Tier 2 Ranking of On-site Livestock Carcass Management Options for
Microbes 195
Table 7.3.4. Effect of Scenario Design or Implementation on Potential Exposures 200
Table 7.4.1. Summary of Livestock Carcass Management Options, Mitigation Measures,
and Research Needs 205
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
List of Figures
Figure 3.1.1. Conceptual model for exposure pathways from livestock carcasses handling 29
Figure 3.1.2. Conceptual model for exposure pathways from temporary carcass storage 33
Figure 3.1.3. Conceptual model for exposure pathways from livestock carcass
transportation 34
Figure 3.2.1. Conceptual model of exposure pathways from on-site open burning of
livestock carcasses 38
Figure 3.3.1. Conceptual model for exposure pathways from on-site air-curtain burning of
livestock carcasses 48
Figure 3.4.1. Conceptual model for exposure pathways from on-site burial of livestock
carcasses 55
Figure 3.5.1. Conceptual model of exposure pathways from livestock carcass composting 64
Figure 4.1.1. Wind rose for Iowa City in 2014 76
Figure 4.1.2 Modeled, annual-total deposited mass of chemicals emitted from open-pyre
and air-curtain burner units, using hourly meteorology 79
Figure 4.3.1 Modeling scenario for chemical movement from buried combustion ash to
groundwater with percolation of water 86
Figure 4.3.2. Well interception of leachate plume from burial trench 90
Figure 5.4.1 Relationship between emerging contaminant groundwater plume from
carcass burial trench to surface water bodies of various sizes 132
Figure 7.1. Chemical ranking ratios by management option and exposure route 179
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:nowledgeraents
The authors wish to acknowledge the contributions of experts who participated in a workshop
held during the 5th International Symposium on Animal Mortality Management on October 1,
2015, in Lancaster, Pennsylvania. The workshop participants reviewed and discussed data and
assumptions used to develop carcass management scenarios and to estimate potential exposures.
Information obtained at the workshop and in follow up communications has been helpful in
refining the exposure assessment approach. Acknowledgements also are due to the following
workshop attendees and other experts who provided follow-up information and support: Dr.
Robert DeOtte, West Texas A&M University; Gary Flory, Virginia Department of
Environmental Quality; Mark Hutchinson, University of Maine Extension; Mark King, Maine
Department of Environmental Protection; Dr. Mike Brown, West Texas A&M University; and
Dr. Andy Cole, United States Department of Agriculture (USDA). Dr. Sandip Chattopadhyay
served as task order contracting officer representative and Dr. Sarah C. Taft served as alternate
contracting officer representative.
Acknowledgements also are extended to reviewers who provided many helpful comments on the
report, including: Lori P. Miller, P.E., USDA, Animal and Plant Health Inspection Service
(APHIS); Dr. Scott Wesselkemper, USEPA; Dr. Randy Bruins, USEPA; Dr. Paul Lemieux,
USEPA; Dr. Kevin Garrahan, USEPA; Anna Tschursin, USEPA; Dr. Eileen Sutker, USDA; Dr.
Craig Ramsey, USDA; and Samantha Bates, USDA.
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Executive Summary
Proper management of livestock carcasses following large-scale mortalities protects humans,
livestock, and wildlife from chemical and biological hazards; maintains air, water, and soil
resources; protects ecological resources and services; and enhances food and agricultural
security. In support of the National Response Framework, the U.S. Department of Homeland
Security (DHS) Science and Technology Directorate funds research in collaboration the U.S.
Environmental Protection Agency's (USEPA's) Office of Research and Development (ORD),
Homeland Security Research Program (HSRP) and the U.S. Department of Agriculture's
(USDA's) Animal and Plant Health Inspection Service (APHIS) to support the proper
management of animal carcasses following major environmental incidents. Mass livestock
mortalities can result from a natural disaster, foreign animal disease (FAD) outbreak, chemical or
radiological incident, or other large-scale emergencies. As a product of the collaborative research
between USEPA and USD A, this report evaluates livestock carcass management options
following a natural disaster through a comparative exposure assessment. This assessment helps
to inform a scientifically-based selection of environmentally protective methods in times of
emergency. Future phases of this project will examine a FAD outbreak and chemical or
radiological incidents.
The livestock carcass management options included in this exposure assessment are seven well-
established methods with sufficient capacity for large-scale carcass management: on-site open
burning (pyre), on-site air-curtain burning, on-site unlined burial, on-site composting, off-site
fixed-facility incineration, off-site landfilling, and off-site carcass rendering.
With the three off-site options, all releases to the environment (e.g., incinerator emissions to air,
rendering facility discharge to surface water) are restricted by, and are assumed to comply with,
applicable U.S. federal regulations. Therefore, chemical and microbial releases from off-site
commercial facilities are assumed to be adequately controlled. The number of potential chemical
and microbial exposure pathways in conceptual models for the three off-site management options
are lower than for the four on-site options. These differences are the basis of a Tier 1 ranking
shown in Table ES.l.
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Table ES.l. Tier 1 Ranking of Livestock Carcass Management Options
Tier 1 Ranking
Management
Options
Chemical
Exposure
Pathways
Microbial
Exposure
Pathways
Controls and Limits to Environmental
Releases
Rank 1:
Negligible to
minimal
exposure —
releases
regulated to
levels safe for
human health
and the
enviromnent
Incineration
6
6
Air emissions regulated under the Clean
Air Act (CAA), including pollution
control equipment (e.g., scrubbers,
filters), with tall stacks to prevent
localized deposition; residuals (i.e., ash)
managed under the Resource
Conservation and Recovery Act (RCRA);
wastewater managed under the Clean
Water Act (CWA).
Rendering
3
2
Releases to air and to water regulated
under the CAA and CWA, respectively.
Landfilling
2
2
Landfill design and operation regulated
under RCRA; controls include leachate
collection and management and methane
recovery.
Rank 2:
Higher exposure
potential—
uncontained
releases to the
enviromnent
Open Burning
10
10
Uncontrolled and unregulated combustion
emissions; possible releases from
combustion ash if managed on site
Air-curtain
Burning
10
10
Partially controlled but unregulated
combustion emissions, possible releases
from combustion ash if managed on site
Composting
8
7
Partially controlled releases from
compost windrow (minor leaching,
runoff, and gas release to air); where
finished compost is tilled into soils,
potential runoff and erosion from
amended soil
Burial
6
6
Uncontrolled leaching from unlined
burial; slow gas release to air.
Note: higher number (10) indicates potential for higher exposure and risk and a low number indicates less potential for exposure.
The top section of Table ES.2 shows that the Tier 1 assessment for chemicals did not rank the
off-site options relative to each other. In a Tier 2 assessment for the on-site management options,
potential exposures are ranked relative to one another for a hypothetical site, using a
standardized set of environmental conditions (e.g., meteorology), assumptions about the scale of
mortality, and how the carcass management options are designed and implemented. Chemical
and microbial exposures are assessed independently due to fundamental differences in
characteristics influencing transport and fate and in their effects on human health and the
environment.
For chemicals, Tier 2 rankings are based on a quantitative assessment in which different methods
are applied to estimate combustion releases to air and subsequent deposition to ground level and
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to assess fate and transport in surface and subsurface soils, groundwater, and an on-site lake.
Exposures were assessed for humans breathing airborne chemicals and ingesting chemicals in
drinking water, home grown foods, and fish caught in the on-site lake. Some options (e.g., air-
curtain burning and open burning) were not distinguishable from each other given data gaps and
uncertainty in modeling. Those options have, therefore, the same relative rank. The findings for
the Tier 2 chemical assessment are summarized in the bottom section of Table ES.2.
Table ES.2. Ranking of Livestock Carcass Management Options for Chemicals
Tier 1 Description
Management Option
Principal Rationale
The qualitative Tier 1 assessment
distinguishes the off-site options from
the on-site options based on level of
regulatory control. The off-site options
are considered to pose lower risk than
the on-site options, which have
uncontrolled enviromnental releases.
The off-site options are not ranked
relative to each other.
Off-site Rendering
Carcasses processed into useful
products; wastes released under permits;
availability decreasing
Off-site Landfill
Carcass leachate contained and methane
captured; landfills at capacity are closed
and new ones built
Off-site Incinerator
Destruction of materials; air emissions
are regulated; ash is landfilled
Tier 2 Description
Rank3
Management
Option
Principal Rationale
The quantitative Tier 2 assessment
ranks the on-site options relative to
each other by comparing ratio of
estimated exposures (from data on
source emissions and fate and
transport modeling) with toxicity
reference values (TRVs).
1
Compost
Windrow
Bulking material retains most chemicals
1
Burial
Soils filter out chemicals traveling
toward groundwater
2
Air-curtain
burning
Similar release profiles; emissions
sensitive to type and quantity of fuels
used and burn temperature
2
Open Pyre
burning
3
Compost
Application
If no offset from lake; mitigate with
offset and erosion controls
a Rank 1 poses the lowest relative risk and higher numbers indicate higher relative risk.
In the Tier 2 assessment for microbes, three pathogenic microbes were evaluated to represent
prions, bacterial spores, and bacterial cells. For these microbes, all estimated exposures were
below available exposure benchmark values. However, because of significant uncertainty about
the initial concentration of the pathogenic microbes in healthy livestock killed by a natural
disaster, the Tier 2 rankings for microbes are based on the degree of thermal destruction and
containment provided by the carcass management options. These rankings assume prions could
survive more management options than spores, and bacteria that do not form spores were most
susceptible to thermal inactivation. Thermal destruction can be applied as a criterion for both the
on-site and off-site options. Tables ES.3 and ES.4 show the microbial exposure rankings for Tier
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1 and Tier 2, respectively. Although the on-site options are not ranked relative to the off-site
options, some will offer thermal destruction comparable to or greater than off-site options.
Table ES.3. Tier 1 Ranking of Off-site Livestock Carcass Management Options for
Microbes
Tier 1 Description
Rank3
Management
Option
Principal Rationale
The qualitative Tier 1 assessment
distinguishes the off-site options from
the on-site options based on level of
H
Off-site Incinerator
Thermal destruction of all microbes, ash
is landfilled
regulatory control. Among the off-site
options, rankings are based
qualitatively on the level of thermal
destruction. Off-site options are not
M
Off-site Rendering
Thermal inactivation of all microbes
except prions, workers protected from
prion exposure with the use of PPE
ranked relative to on-site options,
although some will offer thermal
destruction comparable to or greater
than off-site options.
L
Off-site Landfill
Contaimnent, including liner, leachate
collection, cover material, but no thermal
destruction; when capacity is reached,
landfill is closed and new ones built
Abbreviations: H = Highest rank; M = Middle rank; L = Lowest rank.
a Relative and absolute risks from microbial pathogens depends on initial concentrations in healthy cattle, which is unknown.
Table ES.4. Tier 2 Ranking of On-site Livestock Carcass Management Options for
Microbes
Tier 2 Description
Rankab
Management
Option
Principal Rationale
Rankings in the Tier 2 assessment are
1
Air-curtain
Thermal destruction of all microbes
based on quantitative exposure dose
estimates for a limited number of
2
Open Pyre
Thermal destruction of all microbes
except prions
exposure pathways. For those
pathways and the microbes assessed,
all estimated exposure doses were
below the available ID50 values for
each representative microbe (<7, 3-4,
and ~ 1 order of magnitude lower than
3
Compost:
-Windrow
-Soil application
Thermal inactivation of most microbes
during windrow decomposition phase,
incomplete activation of spore-forming
microbes and prions with some
decay/inactivation expected before the
application of finished compost
the ID50 for Escherichia coli, Bacillus
anthracis, and prions, respectively).
Therefore, the rankings reflect the
extent of thermal destruction.
4
Burial
No thermal inactivation of any microbes,
some decay expected
Abbreviations: ID50 = infectious dose for 50 percent of the exposed population.
a Rank 1 poses the lowest relative risk and higher numbers indicate higher relative risk.
Relative and absolute risks from microbial pathogens depends on initial concentrations in healthy cattle, which is unknown;
qualitative ranking is based on thermal destruction and containment.
Off-site options, including incineration, landfilling, and rendering, are subject to air, water, and
solid waste regulations designed for adequate health and environmental protection. This
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assessment finds that, when properly designed and implemented, the four on-site carcass
management options are unlikely to cause adverse health or environmental effects.
The Tier 2 assessment provides a scientifically based understanding of the relative contribution
of specific exposure pathways, hazardous agents, and steps in carcass management processes.
These insights can assist selection of environmentally protective livestock carcass management
methods in the event of a natural disaster. The assessment also can aid selection and priority
setting for mitigation and best management practices.
In actual natural disasters, many site-specific factors contribute to potential chemical and
microbial exposures from carcass management options. The exposure estimates presented in this
report should not be interpreted as "actual" exposures associated with the management options.
However, site managers can use the findings of this report, in conjunction with site-specific
factors, to make informed decisions about which carcass management options would minimize
risks to human health and the environment for specific locations.
XVI
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Acronyms and Abbreviations
Acronym / Abbreviation
Stands For (Country or Agency Affiliation)
microgram(s)
|im
micro meter(s)
ADD
average daily (ingestion) dose
AEGL
Acute Exposure Guideline Level
AERMET
pre-processor for meteorological data for AERMOD
AERMOD
AMS/USEPA Regulatory Model air dispersion model
A1
aluminum
AMS
American Meteorological Society
APHIS
Animal and Plant Health Inspection Service (USD A)
As
arsenic
AT
averaging time
ATSDR
Agency for Toxic Substances and Disease Registry (CDC)
BAF
bioaccumulation factor
BaP
benzo(a)pyrene
BOD
biological oxygen demand
BSE
bovine spongiform encephalopathy
°C
degrees Celsius
Ca (Ca2+)
calcium (cation)
CAA
Clean Air Act (U.S.)
CAFO
concentrated animal feeding operation
Cd
cadmium
CDC
Centers for Disease Control and Prevention (U.S.)
CDD
chlorinated dibenzo-p-dioxin
CFR
Code of Federal Regulations (U.S.)
CFU
colony forming unit(s)
CJD
Creutzfeldt-Jakob disease
CI
chlorine
CI
chloride (anion)
cm
centimeter(s)
CO
carbon monoxide
COD
chemical oxygen demand
C02
carbon dioxide
Cr
chromium
XVll
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Acronym / Abbreviation
Stands For (Country or Agency Affiliation)
Cu
copper
CWD
chronic wasting disease
DHS
Department of Homeland Security (U.S.)
DNR
Department of Natural Resources (Iowa)
dw
dry weight
ED
exposure duration
EF
exposure factor
EFH
Exposure Factors Handbook
°F
degrees Fahrenheit
FAD
foreign animal disease
FC
fraction contaminated
FDA
Food and Drug Administration (U.S.)
Fe
iron
FFI
fatal familial insomnia
ft
foot (feet)
ft2
square foot (feet)
ft3
cubic foot (feet)
FMD
foot-and-mouth disease
g
gram(s)
gal
gallon(s)
GSS
Gerstmann-Straussler-Scheinker syndrome
H20
water
HAPs
hazardous air pollutants
HCO3
biocarbonate (anion)
Hg
mercury
HOWI
hog farm waste incinerator
HLC
Henry's Law Constant
hr
hour(s)
HHRAP
Human Health Risk Assessment Protocol (USEPA)
HPAI
highly pathogenic avian influenza
HSE
Health and Safety Executive (of the United Kingdom)
HSRP
Homeland Security Research Program
ID
infectious dose
ID50
infectious dose causing illness in 50 percent of the exposed population
XV111
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Acronym / Abbreviation
Stands For (Country or Agency Affiliation)
IPCS
International Programme on Chemical Safety (WHO)
IRIS
Integrated Risk Information System (USEPA)
IR
ingestion rate
K(K+)
potassium (cation)
Kd
soil/liquid partition coefficient
kg
kilogram(s)
km
kilometer(s)
Kow
octanol-water partitioning coefficient
L
liter(s)
lb
pound(s) (weight)
LEL
lower explosive limit
LIWI
livestock disease control incinerator
m
meter(s)
nf
square meter(s)
m3
cubic meter(s)
MCL
Maximum Contaminant Level (USEPA)
MCLG
Maximum Contaminant Level Goal (USEPA)
mg
milligram(s)
Mg
magnesium
MIRC
Multimedia Ingestion Risk Calculator
mL
milliliter(s)
mm
millimeters(s)
Mn
manganese
N
nitrogen
Na (Na+)
sodium (cation)
NABCC
National Agricultural Biosecurity Center Consortium (Kansas State University)
NAWQC
National Ambient Water Quality Criteria
NAWQC-AL
National Ambient Water Quality Criteria for the Protection of Aquatic Life
ng
nanogram(s)
nh3
ammonia
nh3-n
nitrogen measured as ammonia
nh4+
ammonium
NHSRC
National Homeland Security Research Center (USEPA)
NIST
National Institute of Standards and Technology (US Department of Commerce)
Ni
nickel
XIX
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Acronym / Abbreviation
Stands For (Country or Agency Affiliation)
nm
nanometer
NOx
nitrogen oxides
NRC
National Research Council (of the National Academy of Sciences)
NRF
National Response Framework
NSAID
non-steroidal anti-inflammatory drugs
nv-CJD
New variant Creutzfeldt-Jakob disease
OAQPS
Office of Air Quality Planning and Standards (USEPA)
OLEM
Office of Land and Emergency Management (USEPA)
ORD
Office of Research and Development (USEPA)
OW
Office of Water (USEPA)
P
phosphorus
PAHs
polycyclic aromatic hydrocarbons
PAL
Provisional Advisory Levels (USEPA)
Pb
lead
PCDD
polychlorinated dibenzo-p-dioxins
PCDF
polychlorinated dibenzofurans
PeCDD
pentachlorodibenzo -p-dioxin
PM2.5
particulate matter <2.5 microns (nm) in diameter
PM10
particulate matter <10 microns (nm) in diameter
P043"
phosphate (ion)
PPE
personal protective equipment
Pj-pSc
prion causing Scrapie
QA
quality assurance
RCRA
Resource Conservation and Recovery Act (U.S.)
RfD
reference dose
RPF
relative potency factor
S
sulfur
SI
International System of Units
Si
silicon
S02
sulfur dioxide
so42-
sulfate (ion)
SSW
Soil and Surface Water ( Screening Model)
TCDD
tetrachlorodibenzo-p-dioxin
TEF
toxicity equivalency factor
TEQ
toxic equivalency factor
XX
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Acronym / Abbreviation
Stands For (Country or Agency Affiliation)
TKN-N
nitrogen measured as total Kjeldahl nitrogen;
TOC
total organic carbon
ton
U.S. ton(s) (2,000 lb)
tonne
metric tonne(s) (1,000 kg)
TRV
toxicity reference value
TSE
transmissible spongiform encephalopathy
UEL
upper explosive limit
U.S.
United States (adjective)
USD A
United States Department of Agriculture
USEPA
United States Enviromnental Protection Agency
USGS
United States Geological Survey
vCJD
variant Creutzfeldt-Jacob disease
WBAN
W eather-Bureau- Army-Navy
WHO
World Health Organization
WW
wet weight
yd
yard
Zn
zinc
XXI
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
1. Introduction
Established by the U.S. Department of Homeland Security (DHS), the National Response
Framework (NRF) is a single comprehensive approach to domestic incident management. The
NRF provides a context for DHS and other federal departments and agencies to work with
communities to prevent, prepare for, respond to, and recover from hazards such as natural
disasters, acts of terrorism, and pandemics.
In support of the NRF, the DHS Science and Technology Directorate is funding research in
collaboration with the U.S. Environmental Protection Agency's (USEPA's) Office of Research
and Development (ORD), National Homeland Security Research Center (NHSRC) and the U.S.
Department of Agriculture's (USDA's) Animal and Plant Health Inspection Service (APHIS) to
assure the proper management of animal carcasses following major environmental incidents such
as a natural disaster, foreign animal disease (FAD) outbreak, chemical or radiological incident,
or other large-scale emergencies. Proper management, including disposal, of livestock carcasses
following large-scale mortalities
Exposure Assessment Objective
is needed to protect humans, , .
The objective of this exposure assessment is to support selection
livestock wildlife and the °r environmentally protective livestock carcass management
methods in times of emergency by providing scientifically-based
environment from chemical and information on potential hazards posed by management methods
to human health, livestock, wildlife, and the enviromnent.
biological hazards; to maintain
air, water, and soil resources; to protect ecological resources and services; and to enhance food
and agricultural security.
1.1. Purpose and Scope
This Report focuses on relative exposures and hazards for different livestock carcass
management options in the event of a natural disaster. Future phases of this research will rank
management options in the event of introduction of a FAD, a chemical emergency, and a
radiological emergency.
Previous studies (e.g., Gwyther et al. 2011; CAST 2009; NABCC 2004) discussed possible
environmental and public health outcomes of mass livestock mortalities following specific
natural disasters or animal disease outbreak emergencies. At least three studies (i.e., Gwyther et
al. 2011; Pollard et al. 2008; UKDH 2001) also provided comparative analyses to rank carcass
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
management options (e.g., on-site burial, incineration). Past research relied primarily on
qualitative methods or observations based on incident-specific circumstances, which limits its
predictive value.
This Report presents a quantitative exposure assessment by which livestock carcass management
options are ranked relative to one another for a hypothetical site setting, a standardized set of
environmental conditions (e.g., meteorology), and following a single set of assumptions about
how the carcass management options are designed and implemented. These settings, conditions,
and assumptions are not necessarily representative of site-specific carcass management efforts.
Therefore, the exposure assessment should not be interpreted as estimating levels of chemical
and microbial exposure that can be expected to result from the management options evaluated.
The intent of the relative rankings is to support scientifically-based livestock carcass
management decisions that consider potential hazards to human health, livestock, and the
environment. This exposure assessment also provides information to support choices about
mitigation measures to minimize or eliminate specific exposure pathways.
1.2. Report Organization
The remainder of this Report is organized in seven sections. Section 2 explains the basic
conclusions of problem formulation, while Section 3 describes the conceptual models in more
detail for each livestock carcass management option, including carcass transportation and
handling. The analyses for chemicals are included in Sections 4 and 5. Section 4 focuses on
environmental releases, transport, and fate of chemicals from each carcass management option,
and Section 5 presents estimated human exposures to chemicals via inhalation from air and total
ingestion exposures from all sources (e.g., drinking water, eating fish, consuming crops) for each
livestock carcass management option. For chemicals, Section 5 also discusses possible
environmental consequences of each carcass management option. Microbial releases, transport,
and fate in the environment are described more qualitatively than for chemicals. Section 6
focuses on microbial exposure pathways for humans, other livestock, and terrestrial and aquatic
habitats. Potential exposures among the livestock carcass management options are compared in
Section 7. In particular, exposures estimated the livestock carcass management options are
compared with health benchmarks and the results are used to rank the management options in
terms of their potential for adverse health effects. Section 7 also summarizes uncertainties in the
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
assessment data and methods, and discusses how different scenarios or assumptions would affect
potential exposures. In addition, Section 7 discusses mitigation measures and best management
practices to address potential exposures, and identifies research needs that would support further
understanding of exposures and other potential impacts of the management options. The Report
concludes with quality assurance documentation in Section 8 and references cited in Section 9.
All appendices are included at the end of this Report.
1.3. Unit Conventions
Calculations for the exposure assessment were performed using metric system units consistent
with the International System of Units (SI) as described by the National Institute of Standards
and Technology (NIST 2008). Many of the information sources for the exposure assessment used
U.S. customary units (e.g., feet, pounds). Quantitative information from these sources is
introduced in their original units followed by metric system equivalents in parentheses. The
metric equivalents are used thereafter in the Report.
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
2. Problem Formulation
Problem formulation for the exposure assessment defines the scope of the assessment, including
the natural disaster scenario and scale of mortality, the livestock carcass management options
and associated activities to be evaluated, and the hazardous materials that could be released to
the environment for each option. It also defines a set of standardized environmental conditions
and specifies the initial mass of livestock carcasses as 50 U.S. tons (45,359 kg) for all
management options. The livestock are assumed to be healthy at the time of death and intact
when collected for management. Implementation of carcass management is assumed to be
prompt (i.e., not delayed or otherwise affected by disaster conditions, e.g., flooding, damage to
roads or structures).
To establish an exposure scenario that encompasses all of the possible exposures and that might
reasonably be expected from the livestock carcass management options, livestock mortality is
assumed to occur at a hypothetical farm. The location and regional factors do not preclude the
availability or feasibility of any carcass management option (e.g., no shallow water tables).
Humans potentially exposed include adult and child residents and workers participating in
carcass management. The farm includes agricultural fields and a home garden that supplies the
farm residents' fruits and vegetables. The residents also produce their own livestock food
products at home, including beef, dairy, pork, poultry, and eggs; fish for consumption are caught
in an on-site lake. Farm residents obtain drinking water from an on-site groundwater well.
A large number of chemicals and microbes are potentially released to the environment from
carcass management options, some of which are more likely than others to be hazardous at
estimated or likely environmental concentrations; some of the chemicals and microbes might
pose negligible risks from any management option. Included in the exposure assessment are
chemicals identified in scientific literature as being present in carcass management wastes and
by-products (e.g., leachate, incineration emissions), including chemicals formed from fuels used
in the combustion of carcasses. Microbes included in the exposure assessment were ones that
could be present in cattle not exhibiting signs or symptoms of illness and considered to be free of
disease. The list of assessed microbes was narrowed to a subset expected to remain viable during
and after the carcass management process.
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
This section summarizes the assumptions that apply to the entire assessment, including selection
of management options, hazardous agents, and standardized environmental settings and
scenarios. The assumptions for specific livestock carcass management options are identified in
Section 2 with discussion of the management-specific conceptual models.
2.1. Livestock Carcass Management Options
The management options considered for the exposure assessment are those with documented use
following natural disasters or that are likely to have sufficient capacity for large-scale carcass
management. These include seven well-established methods, which can be categorized into three
groups:
Table 2.1.1. Livestock Carcass Management Options Considered for the Exposure
Assessment
Management Type
Specific Management Option
Combustion-based Management
¦ On-site Open Burning (Pyre)
¦ On-site Air-Curtain Burning
¦ Off-site Fixed-facility Incineration
Land-based Management
¦ On-site Unlined Burial
¦ On-site Composting
¦ Off-site Lined Landfill
Materials Processing
¦ Off-site Rendering
The carcass management options can also be categorized as on-site or off-site. The on-site
management methods (open burning, air-curtain combustion, burial, and composting) typically
are performed on the livestock owner's property if a suitable location is available. Therefore,
residues from the management method could remain in compost windrows, burial trenches, or
ash buried at the combustion site. In addition to the biomass residues, there also will be remnants
of any additional materials used for the management process, such as woodchips or straw from
composting, residual ash from wood or coal used to burn carcasses, and chemical byproducts
from accelerants such as petroleum products. For composting, two phases are evaluated: the
compost windrow for one year and application of finished compost to farm soils at the end of
that year.
Finally, the carcass management options can be categorized by degree of containment. Open
pyres and unlined burial do not include constructed barriers to prevent the movement of
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
substances away from the carcass management site (Table 2.1.2). For air-curtain combustion and
composting, there are some constructed barriers inhibiting movement of chemicals and microbes
from the carcass management location to the environment. For off-site commercial landfills,
commercial incinerators, and rendering facilities, releases from the facility are restricted by
regulations designed to protect human health and the environment. For this comparative
exposure assessment, all management options are assumed to operate in compliance with
applicable regulations and best practices so that releases from commercial off-site facilities are
within permitted limits. Thus, exposures from permitted releases from the three regulated off-site
management options (i.e., rendering, commercial incineration, placement in lined landfills) are
not evaluated, although exposure from transporting the animal carcasses from the farm to the off-
site facility is assessed.
Table 2.1.2. Containment of Releases from Management Options
Combustion
Land Based
Material Processing
On-Site
Off-Site
On-Site
Off-Site
On-Site
Off-Site
Air Curtain
Incineration
Composting
Landfill
Not Evaluated
Rendering
Open Burning
(Pyre)
Burial
¦ = Releases restricted by regulation
= Releases partially restricted by physical barriers
= No barrier to releases
The two on-site combustion options (air curtain and open burning) release gases and particles to
air during the few days of active burning. Combustion products released to air, primarily those in
particle-phase, will deposit back to ground-level (i.e., surface soils, crop and grass surfaces, and
surface water), with more deposited closer to the source than farther away and with heavier
particles deposited closer to the source than lighter particles. Dry deposition of particles in the
vicinity of the site would occur over roughly the same time as the active combustion.
After combustion ceases, the materials deposited to soils can move over months to years due to
precipitation. On the hypothetical farm, chemicals and microbes deposited to surface soils (and
plants) move downgradient via runoff and erosion toward the lake, where aquatic plants and
animals, including fish, could be exposed.
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
Leaching of chemicals and microbes from buried ash (remaining from combustion options), from
buried carcasses, from compost windrows, and from compost applied to soils also could occur
slowly over months and years. Soils would filter some materials out of the leachate, but some
might reach groundwater used for the on-site well or reach the lake through groundwater
recharge.
This report uses a standardized scenario and set of environmental conditions to estimate the
relative exposure potential among the seven carcass management options as discussed in Section
2.2.
2.2, Standardized Conditions
For all carcass management options, the exposure assessment evaluates the management of 50
U.S. tons (45,359 kg) of carcasses. For cattle, that mass would equal 100 animals if they each
weighed 454 kg (1,000 lb). For swine, that mass would equal 565 hogs if they each weighed 80
kg (177 lb). For broiler chickens, the mass would include 25,000 birds averaging 4 lb (1.9 kg)1
each. For turkeys, 5,000 birds averaging 20 lb (9.1 kg)2 each would constitute 45.4 tonnes (50
U.S. tons) of carcasses. Based on criteria discussed in Section 3.1, carcass management is
assumed to take place at hypothetical farm in Iowa.
Mass livestock losses can result from extreme storms, floods, extreme cold and severe winter
weather, extreme heat and drought, and fire (USDA 2002; NABCC 2004). From 1998 through
2000, federally-declared natural disasters in the United States included 29% thunderstorms, 22%
floods, 15%) tornadoes, 12%> winter storms, 10%> hurricanes, 8%> tropical storms, 2%> mudslides,
2% wildfires, and 1%> earthquakes (USDA 2002). Other disasters that could cause livestock
losses are much less frequent in the United States (e.g., avalanche or landslides, tsunamis,
volcanic eruption).
Different types of natural disasters can affect the potential for chemical and biological exposures,
as well as the feasibility of using specific carcass management options. Storms, hurricanes,
tornadoes, and floods can leave the landscape inundated with water, precluding use of some
'httpV/icea.agr.hr/articles/SOO Comparison of slaughter yield and carcass tissue compisition in broiler chickens of various
origin en.pdf
2 Turkeys sold for human consumption weigh from 12 to 22 pounds when packaged (USDA 2013a). Whole carcasses would
weigh more; therefore 20 pounds per turkey is assumed.
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
types of carcass management methods (e.g., on-site burial, combustion) and hampering transport
of carcasses across flooded areas to off-site carcass management locations. This assessment is
limited to releases of hazardous substances from livestock carcass management; it does not
address other problems that might accompany specific natural disasters (e.g., blocked roadways,
overflow from manure settling lagoons, increased mosquito populations). Hazards and exposures
to hazardous materials from carcasses remaining in place for many days or weeks differ from
those expected if carcass collection and management occurs within one or two days. To
standardize conditions across disaster types, physical effects of the disaster are not considered
and are assumed not to impede timely implementation of any of the carcass management options.
Other assumptions to standardize conditions across livestock carcass management options are
listed in Table 2.2.1. Readers are cautioned that several of the assumptions would not apply to
any given actual emergency mass mortality from a natural disaster in a given area of the country.
2.3. Site Setting and Environmental Conditions
The hypothetical farm establishes an exposure scenario that encompasses possible exposure
pathways to humans. A hypothetical location in Iowa was chosen as the site setting because of
the predominance and diversity of agricultural activities in the central Midwest and because this
region generally is not characterized by extreme weather conditions (e.g., aridity).
The farm includes agricultural fields for fruits and vegetables, a lake, a groundwater well
providing water for household uses, irrigation, and raising livestock, and grazing/feeding areas
for livestock. For each option, the farmer must manage 45,359 kg (50 U.S. tons) of livestock
carcasses killed by the natural disaster on the farm.
1.1.1. Site Location and Meteorology
Multimedia exposure modeling requires assumptions about topographical, hydrogeological, and
meteorological conditions in the modeling domain. Land cover near a farm can affect
atmospheric stability and moisture availability. Meteorological parameters such as wind,
temperature, atmospheric mixing height, atmospheric stability, and precipitation directly affect
air dispersion and subsequent deposition of emissions from on-site combustion. Precipitation
affects the rates of runoff and erosion from soil and leaching to groundwater.
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
Table 2.2.1. Standardized Conditions and Assumptions
Issue
Assumptions
Carcass Management and Post-
Management Assumptions
¦ Carcass management options include those with documented use following
natural disasters or believed to have sufficient capacity for large-scale carcass
management.
¦ The exposure assessment begins with collection of carcasses from where
animals died and their placement in a single above-ground storage pile on-site.
¦ Workers move the carcasses from the storage pile to the management location
(e.g., placement in a burial trench, trucking off-site to a landfill) within 48 lir.
¦ Exposures to hazardous materials released from management units and from
post-management processes (e.g., residuals disposal) are both assessed.
¦ On-site management options are designed and operated in compliance with
applicable state and federal guidance and regulations.
¦ Off-site commercial management options include contaimnent technologies that
should restrict emissions to permitted levels. Moreover, the releases of particles
and chemicals at or below regulatory limits are assumed to be health protective.
Therefore, the three regulated, off-site carcass management options (i.e.,
placement in landfills, commercial incineration, and rendering) are not assessed
for chemical releases.
Disaster Type and Disaster-
Related Effects
¦ The initial mass livestock loss is a result of a natural disaster (type unspecified)
and not a disease or culling of livestock to prevent disease.
¦ Carcasses are distributed across the farm for all management options (i.e., not
comparing mass mortalities in rangelands to those in concentrated animal
feeding operations [CAFOs]).
¦ Carcasses are not damaged by the disaster and are intact (Willis 2003) when
collected and placed in the storage pile2. Upon placement in the storage pile,
carcasses begin to decompose and release liquid.
¦ Disaster conditions (e.g., flooding, road damage, extreme weather incidents) do
not impede collection, movement, or handling of the carcasses or
implementation of any of the carcass management options.
Livestock Types
¦ The exposure assessment focuses on the management of cattle carcasses. Other
livestock categories (e.g., swine and poultry) are discussed where relevant.
Category-specific livestock characteristics (e.g., body size) influence handling
and management of carcasses (e.g., poultry and juvenile pigs can be moved by
hand, movement of cattle and hogs requires heavy equipment), whereas other
characteristics are similar across categories (e.g., basic elemental composition
of terrestrial vertebrate animals).
Hazard Types
¦ Hazardous agents of concern include chemical and biological agents released
directly from decomposing carcasses or from carcass management (including
any added materials) and post-management processes.
¦ Prior to death all livestock are healthy and are asymptomatic even if virulent
strains of pathogenic microbes are present in their gut flora.
¦ Other types of hazards caused by natural disaster conditions (e.g., flooding,
extreme temperature) are not evaluated.
¦ Accidents (e.g., transport vehicle turnover, rainstorm on open pyre that could
end blaze and result in substantial smoldering, road washout) that could affect
implementation of a carcass management option do not occur.
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
Issue
Assumptions
Scale of Livestock Mortality
¦ For all carcass management options, 45,359 kg (50 U.S. tons) of carcasses are
managed.
Geographic and Spatial Issues
¦ All carcass management activities take place at a hypothetical site in Iowa.
¦ All carcass management options are evaluated with identical on-site spatial and
geographic assumptions (e.g., same size watershed, nearby water bodies,
precipitation land gradient, depth to aquifers).
¦ The site location and regional factors do not preclude the availability or
feasibility of any carcass management option (e.g., no shallow water tables).
¦ A single set of values are used for meteorological and other enviromnental
parameters (e.g., wind speed, air mixing height, soil porosity, soil fraction
organic carbon, slope and erosion rates, rainfall-related soil percolation and
runoff rates). The values are based on data from a representative agricultural
region, nationally representative values (if available and vetted as such by
USD A or USEPA), and/or health protective values.
Human Health
¦ Farm residents consume farm products as part of their regular diet.
¦ Farm residents are not exposed to other chemicals or other sources of the
chemicals analyzed in this report (that is, all doses are directly from the carcass
management option).
¦ Worker exposures arise solely from the carcass management option.
Legal Requirements
¦ All federal requirements must be met.
¦ The hypothetical setting as a farm in Iowa does not mean that State of Iowa
requirements for carcass management1 would necessarily be met because that
would limit the general applicability of the assessment for emergency mass
livestock mortalities.
Abbreviations: hr = hours.
1 Examples of State of Iowa requirements include that those disposing of dead animals must have a license from the
department (Iowa Code §167.2); transporters must be licensed (167.15); disposal must be within 24 hours
(167.12(7)), burial must be more than 4 feet deep in the soil and the use of quicklime is required during burial
(167.12(6)); disposal must be within a reasonable time after death by composting, cooking, burying, or burning
(167.18); open-air burning must be within 24 hours if the animal dies of anthrax or hog cholera (Iowa
Administrative Code Chapter 61 21—61.29(167), 61.30(167)).
Iowa Administrative Code § 567-100.4(2)(b)(2): A maximum loading rate of 7 cattle, 44 swine, 73 sheep or lambs
or 400 poultry carcasses on any given acre per year. All other species will be limited to 2 carcasses per acre.
Animals that die within two months of birth may be buried without regard to number.
2 There is a short window of time for proper disposal of animal carcasses following their death. Within 7-10 days of
death, dependent upon the outside ambient temperatures, animal carcasses become too decomposed/fragile to handle
easily with disposal equipment.
To compare the livestock carcass management options for their relative exposure potentials,
environmental characteristics must be the same across options. For this project, one year of
meteorological data from the National Oceanic and Atmospheric Administration (NOAA)
provides a reasonable (i.e., realistic) combination of hourly temperatures, wind speeds and
direction, and precipitation frequency and intensity. To realistically represent daily temperature
fluctuations and precipitation on an hourly basis for air dispersion modeling, ground-level
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
meteorological data for the year 2014 were obtained from a station in Iowa City, Iowa (call sign
KIOW; Weather-Bureau-Army-Navy [WBAN] identifier 14937). To estimate air mixing height,
twice-daily upper-air data for the same year were obtained for Davenport, Iowa (call sign
KDVN; WBAN identifier 94982). Sub-hourly wind data were available from Iowa City.
2.3.3, Soils, Crops, and Grazing Lands
The hypothetical farm is located in a predominantly agricultural setting and includes both
livestock and crop agriculture on site. Grazing pastures for cattle receive contaminants deposited
from the air. Crops grown on site include fruits and vegetables that are consumed by the farm
residents. On-site crop agriculture is assumed to supply livestock feed and food for the residents,
including beef, pork, poultry, eggs, and dairy products.
As stated above, the two combustion-based carcass management options release gases and
particles to air (e.g., the smoke). Airborne particulates can deposit to soils, crops, and grazing
land via wet and dry deposition.
Compost windrows are localized; however, finished compost applied to fields spreads the
remaining materials, and possibly viable prions and spore-forming microbes over surface soils.
Precipitation can move chemical or microbial contaminants in the top few cm of soil to the on-
site lake via runoff or erosion.
2.3.4, Lake and Aquatic Food Web
The residents also consume fish caught in an on-site lake. For sustainable populations of game
and pan fish (e.g., largemouth bass and sunfish, respectively), the lake must be more than a few
acres in size. A 40.5 ha (100 ac or 404,700 m2) lake could support sustainable populations of
game fish (i.e., top carnivores in the food chain), which could accumulate relatively high
concentrations of any bioaccumulative chemicals loaded to the lake. Smaller lakes (e.g., 4.05 ha
or 10 ac) could support sustainable populations of pan fish. Based on a database for lakes in
Minnesota, an average "maximum" depth for a 40.5 ha (100 ac) lake is 7.62 m (25 ft). An
average maximum depth for a 4.05 ha (10 ac) lake is 4.57 m (15 ft). Using an empirical formula
to estimate average lake depth from maximum lake depth,3 the average depth of a 40.5 ha lake
3 The equation, Average Lake Depth = eA(0.727*ln(Maximum Lake Depth), was developed by ICF International in support of a
previous application of HHRAP.
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
would be 4.38 m (14.4 ft) and the average depth for a 4.05 ha (10 ac) lake would be 3.02 m (9.9
ft). The volume of a 40.4 ha lake would therefore be 1.8E+06 m3 or 1.8E+09 L, and the volume
of a 4.04 ha lake would be 1.2E+05 m3 or 1.2E+08 L, i.e., the product of surface area and
average depth.
The lake includes the water column and a bottom sediment layer. The water column can receive
chemicals released from carcass management locations via deposition from the air, overland
runoff and erosion from soil, and/or groundwater recharge.
For combustion-based carcass management options, the combustion location is assumed to be
30.5 m (100 ft) upwind of the lake. Thus, air deposition of gases and particles would occur
primarily in the direction of the lake, with some fraction depositing directly to the lake and the
remaining particles depositing to soil and plant surfaces. Following the actual combustion over a
few days, the chemicals and microbes deposited to soils would be subject to erosion, runoff, and
leaching from the surface soils. Assuming that the lake is the lowest area within a 202 ha (500
ac) watershed (for both lakes), with a slope of 5%, the direction of erosion and runoff would be
toward the lake. Groundwater is assumed to intersect the lake bed and to contribute to the
contaminant load in the lake water column. The distance of groundwater travel between the
location of combustion and the lake is assumed to be 30.5 m (100 ft) (Freedman and Fleming
2003, NABCC 2004).
2,3,5, Groundwater Well
A groundwater well is located on the farm. Considering the four on-site livestock carcass
management options, state-recommended off-sets for private groundwater wells were identified
only for on-site burial and composting. For those two management options, 100 ft (30.4 m) is the
minimum offset identified to date (e.g., Iowa Department of Natural Resources [DNR] 2013,
California WRCB 2015, Freedman and Fleming 2003, NABCC 2004). A longer distance is
required between a burial site and a public groundwater well (e.g., Iowa DNR recommends 200
ft).
1.4. Hazardous Agents
A large number of different types of chemicals and microbes might be released to the
environment from each of the on-site carcass management options. Chemicals include all those
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
derived from biotic and abiotic degradation of animal carcasses (e.g., carbon dioxide, ammonia,
phosphate, sulphate, elemental cations and anions, intermediate degradation products). For
combustion-based management options, additional chemical products of pyrolysis include
polycyclic aromatic hydrocarbons (PAHs) and dioxins and furans produced by combustion of the
carcasses and added fuels. Microbes include those present in the gastrointestinal tract of healthy
animals (e.g., Escherichia coli 0157:H7), including the microbial fauna that assists ungulates
digest plant materials, and other microbes frequently found in livestock feces (e.g., Escherichia
coli 0157:H7, Salmonella spp., Shigella spp.). Several selection criteria focused the exposure
assessment on a subset of chemicals and microbes, as described in Sections 2.4.1 and 2.4.2,
respectively.
1.4.1. Chemical. Agents
Considering all the chemicals in livestock carcasses, the quantities released cannot exceed the
total content of the fresh carcasses. Young et al. (2001; based on Forbes 1987) estimated the total
content of a cattle carcass weighing 454 kg (1,000 lb) for four elements as:
¦ Carbon (C): 355 kg (35.5% by mass)
¦ Nitrogen (N): 40 kg (4%)
¦ Chlorine (CI): 0.13 kg (0.13%)
* Potassium (K): 3.0 kg (0.30%)
Releases of those elements in various compounds or forms (e.g., carbon dioxide, ammonia,
chloride anions, potassium cations) are not likely to exceed the quantities listed above for each
454 kg of livestock carcasses. Most of the chemical mass in mammalian and avian carcasses is
water (FhO, 55—60%) (Young et al. 2001). Some scientists estimate or assume higher water
content and lower carbon content for cattle carcasses (e.g., 75% water, 18% carbon, 3% nitrogen,
and 3% hydrogen; SKM 2005).
Three criteria were used for selecting/identifying chemicals for an initial list. The chemicals are:
1) Naturally present in carcasses
2) Created from combustion or decomposition of carcasses
3) For the combustion-based management options, present or created by the fuels used to
burn carcasses
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
The list of chemicals and their sources as analyzed in this report are summarized in Table 2.4.1.
Additional criteria allowed elimination of a subset of the chemicals or their potential exposures
in particular media or for particular time-frames from further consideration, as explained in
Table 2.4.2.
Two types of organic chemicals are not naturally found in livestock, but are formed during
combustion of carcasses and fuels used to burn them: PAHs and dioxins/furans. Those two
chemical groups include many different congeners. PAHs are formed during incomplete
combustion of most organic materials, including coal, gas, oil, wood, garbage, and other
materials originating from plants and animals. In nature, PAHs are created by forest and brush
fires and from volcanic eruptions. There are more than 100 different PAHs identified, and
mixtures of multiple PAHs generally result from combustion (ATSDR 1995). Various mixtures
of PAHs also occur in substances such as crude oil, coal, coal tar pitch, creosote, and roofing tar
(ATSDR 1995).
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
Table 2.4.1. Chemicals/Agents Retained for Exposure Assessment for Management Options
Chemical
Medium,
Duration
Reason Retained for Assessment
CO, nh3, co2,
NOx, SO2 (gas) from
combustion-based
management options
Air, short-
term
Gases possibly of concern for acute toxicity if air concentrations sufficiently
high at receptor location; dilution dispersion and advection in open air once
the emissions leave the management option might reduce concentrations to
nontoxic levels at relatively short distances.
Methane
Soils, long-
term
From anaerobic decomposition; risk of explosion if methane accumulations
occur in closed buildings and if ignited.
PM2.5. PM10
Air, short-
term
Hazardous via inhalation; can carry and deposit sorbed hazardous chemicals,
can impair visibility.
PAHs
Air and
leachate,
long-term
Both vapor-phase and particle-phase PAHs are produced during combustion
of carcasses and fuels; some are carcinogenic. Particle-phase PAHs can
deposit onto plants, soils, and surface waters. Naphthalene is the most
abundant PAH produced by carcass combustion (~ 50%; Chen et al. 2003;
USEPA 2013a), but it is highly volatile and is expected to remain in vapor-
phase.
Dioxins and furans
Air, long
term
Produced from combustion of fossil fuels, wood, and other auxiliary fuels
used in combustion-based management options. Although primary release is
through air, primary exposure is indirect through the food chain after transport
and subsequent deposition. Currently there are no data directly evaluating
amounts of dioxin or furan release from carcass burning.
NH3 and NH4+
Leachate,
long-term
From decomposition of proteins in buried or composted carcasses. Changes
nutrient status of surface soils and surface waters. In aerobic enviromnents
(e.g., compost windrows), can be converted to nitrates or nitrites, which are
toxic to infants.
Cl\ Na+ Ca2+ K+
Leachate
first 2.5
months
Included in monitoring data for leachate contamination; most will leach out of
carcasses and buried ash over first 2.5 months. Chloride is highly mobile in
soils because it is a low molecular weight anion; cations exchange with other
cations loosely bound to soil particles. Chloride often used as an indicator of
water movement (Glanville et al. 2006).
Fe, Cd, Cr, Cu, Mn,
Ni, Pb, Zn
Air (in fly
ash) and
Leachate,
long-term
Cu added to livestock feed to promote growth Fe to improve hemoglobin
levels, Zn to improve skin and fur condition Mn as a nutrient supplement
(although concentrations in carcass leachate measured by Pratt and Fonstad
2009 < 1 mg/L). Elevated levels of Pb and Ni identified in pig excrement
from unknown sources, possibly from soil amendments (see Chen et al.
2004).
Phosphate (PO43),
sulfate (SO42 )
Leachate,
long-term
Can change nutrient status of surface soils and surface waters.
Biological oxygen
demand (BOD)
Leachate,
long-term
Can reduce oxygen content in soils and surface waters.
Chemical oxygen
demand (COD)
Leachate,
long-term
Can reduce oxygen content in soils and surface waters.
As
Leachate
Highly toxic, naturally exceeds USEPA's drinking water criterion (10 |ig/L)
in groundwater in some areas of the United States. In 2013, the U.S. Food and
Drug Administration (FDA) banned use of most organic arsenical drugs (98
of 101 arsenic-based animal drugs) from poultry and pig feeds. In 2014, FDA
withdrew approval for roxarsone and two new drugs: arsanilic acid and
carbasone. In 2015, FDA withdrew approval of nitarsone, the only remaining
arsenic-based drug used in poultry feeds. It could be used through the end of
2015. Thus, as of January 1, 2016, there are no arsenic-based drugs registered
for use in livestock feed.
Abbreviations: PM2.5 = particulate matter 2.5 micrometers diameter or smaller; PM10 = particulate matter 10 micrometers
diameter or smaller; PAHs = polycyclic aromatic hydrocarbons; BOD =biological oxygen demand; COD = chemical oxygen
demand.
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
Table 2.4.2. Justifications to Eliminate Chemicals or Their Exposure Sources or Durations
from Exposure Assessment for Carcass Management Options
Chemical
Medium,
Duration
Reason Eliminated
CO2, NOx, SO2 from
combustion-based
management options
Air, long-
term
Gases eliminated from concern for chronic toxicity or long-term adverse
enviromnental effects (e.g., greenhouse gases, acid rain), because they are
released in much greater quantities by other point and non-point sources and
disperse quickly in air from a single source.
CO, NH3 from
ground-based
management options
Air long-
term
Gases eliminated because long-term releases from ground-based management
options will be at low concentrations.
ELS, mercaptans from
ground-based
management options
Air long-
term
Odor-causing gases resulting from anaerobic decomposition of carcasses
underground; should not be a concern for properly buried or composted
carcasses or at landfills with gas recovery technology.
Cl\ Na+ Ca2+ K+
Leachate
after 2.5
months
Although these ions contribute to salinity and ionic strength of water, they
are not toxic per se at low concentrations.
HCO3-
Leachate,
long-term
Bicarbonate complexes with some proportion of cations in leachate and
buffers pH in soils. Although of low toxicity, the presence of bicarbonate can
affect pH and the mobility of other chemicals.
Hg
Air and
leachate,
long-term
Mercuric compounds are no longer used as fungicides in animal feeds.
Although ubiquitous in the enviromnent, most investigators of carcass
management options do not analyze samples for Hg. The purpose of this
report is to generate comparable enviromnental assessments of disposal
options and not to generate applicable human health assessment numbers. In
the absence of the mercury pathway, this assessment constitutes an important
first step.
A1
Leachate,
long-term
Concentration in leachate is low (<1 mg/L) relative to toxicity (Pratt and
Fonstad 2009).
Si, Mg
Leachate,
long-term
Soluble silicon and magnesium concentrations in leachate are low (e.g., 20 to
40 mg/L, Pratt and Fonstad 2009) compared with toxic concentrations via
ingestion.
In the early 1980s, USEPA identified 16 PAHs as potentially hazardous to humans based on both
toxicity and occurrence in the environment (ATSDR 1995):
¦ naphthalene,
¦ acenaphthene,
¦ acenaphthylene,
¦ anthracene,
¦ benz(a)anthracene,
¦ benzo[a]pyrene,
¦ benzo[b]fluoranthene,
¦ benzo[g,h,i]perylene,
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
¦ benzo[k]fluoranthene,
¦ chrysene,
¦ dibenz[a,h]anthracene,
1 fluoranthene,
1 fluorene,
1 indeno[l,2,3-c,d]pyrene,
¦ phenanthrene, and
¦ pyrene.
Those 16 PAHs are suspected to be the most harmful, and they have been identified at Superfund
sites at higher concentrations that most other PAHs (ATSDR 1995). Naphthalene, a two-ringed
PAH, often is the predominant product (e.g., almost 50%) of the combustion of the organic
materials including carcasses and auxiliary fuels noted above (Black et al. 2012a,b; Chen et al.
2003; Choi 2014; Johansson and Bavel 2003; USEPA 2013b). More than 98% of naphthalene,
however, remains in vapor phase rather than sorbing to particulates. Cyclopenta(c,d)pyrene and
perylene (5 rings), benzo(b)chrysene (6 rings), and coronene (7 rings) also are frequently
measured in emissions from combustion of organic materials including carcasses and woody
fuels for open pyre and air-curtain burning (Black et al. 2012b; Chen et al. 2003; Choi 2014).
Appendix A lists the physicochemical and toxicological properties of the 21 PAHs identified
above.
Dioxins, unless separately identified in this report, include polychlorinated dibenzo-p-dioxin
(PCDD) compounds and polychlorinated dibenzofurans (PCDFs). Dioxins can bioaccumulate in
the fatty tissues of fish and other animals and can be of concern in milk products from exposed
cattle and goats because of the high lipid content of milk. Dioxins are hydrophobic (also called
lipophilic), resistant to metabolism, and persistent in the environment (USEPA 1994, 2012).
Their toxicity depends on the degree of chlorination and which functional sites on the molecule
are substituted with chlorine (i.e., the congeners with chlorine substituted at the 2,3,7, and 8
positions are the toxic isomers), and 2,3,7,8-tetrachlorinated dibenzo-p-dioxin (2,3,7,8-
tetrachlorodibenzo-/>dioxin [TCDD]) serves as the index chemical for relative toxicity factors
(USEPA 2010). Dioxins are expected as a product from the combustion of fossil fuels and
woody products. Unfortunately, data on dioxin and furan releases measured from combustion of
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
carcasses are currently not available. Section 3 describes the data and assumptions used to
estimate chemical emissions from combustion of carcasses and fuels.
The dioxins analyzed for this report include dioxin and furan congeners with chlorine
substitutions in the 2, 3,7, and 8 positions, which USEPA considers to be the most toxic (USEPA
2010). Appendix B lists the chemical/physical and toxicological properties of the dioxins listed
below:
¦ octaCDD, 1,2,3,4,6,7,8,9-
• octaCDF, 1,2,3,4,6,7,8,9-
¦ heptaCDD, 1,2,3,4,6,7,8-
- heptaCDF, 1,2,3,4,6,7,8-
- heptaCDF, 1,2,3,4,7,8,9-
- hexaCDD, 1,2,3,4,7,8-
¦ hexaCDF, 1,2,3,4,7,8-
¦ hexaCDD, 1,2,3,6,7,8-
• hexaCDF, 1,2,3,6,7,8-
¦ hexaCDD, 1,2,3,7,8,9-
• hexaCDF, 1,2,3,7,8,9-
¦ pentaCDD, 1,2,3,7,8-
¦ pentaCDF, 1,2,3,7,8-
- hexaCDF, 2,3,4,6,7,8-
¦ pentaCDF, 2,3,4,7,8-
1 tetraCDD, 2,3,7,8-
¦ tetraCDF, 2,3,7,8-
Table 2.4.3 provides a final list of chemical hazards by management option. Not included are
veterinary pharmaceuticals (e.g., antibiotics and hormones), detergents, and disinfection
byproducts. Few data are available by which to evaluate veterinary pharmaceuticals in leachate
from carcass burial (e.g., Yuan et al. 2013), and it is unlikely that measurable amounts will be
released to air as parent compound from burning carcasses. FAD control guidelines (e.g., USDA
2013b) include the use of disinfectants to decontaminate vehicles and equipment because they
are necessary to reduce the spread of disease causal agents. In contrast, disinfectants are not
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
absolutely necessary in a natural disaster scenario because the carcasses are from healthy
animals. For this reason, disinfectants are not included in the chemical agents selected for this
exposure assessment. Although detergents are necessary to clean equipment during a natural
disaster, detergent use is expected to be similar among the management options and so are not
included in the exposure assessment.
Table 2.4.3. Chemical Hazards Possibly Associated with each Management Option
Management
Type
Specific Management
Option
Chemical Hazards
Combustion-
based
Management
On-site Open Burning
(pyre) and Air-curtain
Burning
Air: PAHs, dioxins, As, Cd, Cr, Cu, Fe, Mn Ni, Pb, Zn
Ash: PAHs, dioxins. As, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Zn
Off-site Fixed-facility
Incineration
Regulated releases - not assessed
Land-based
Management
On-site Unlined Burial
Potential plant nutrients (N, P, and S compounds), methane. As,
Cd, Cr, Cu, Fe, Mn Ni, Pb, Zn
On-site Composting
Potential plant nutrients. As, Cd, Cr, Cu, Fe, Mn Ni, Pb, Zn
Off-site Lined Landfill
Regulated releases - not assessed
Material
Processing
Off-site Rendering
Regulated releases - not assessed
Abbreviations: PAHs = polycyclic aromatic hydrocarbons.
2.3.6. Microbes
A wide range of microbes are potential hazards associated livestock carcass management
options. These microbes, listed in Table 2.4.4, include only organisms that may be present in
livestock that are not exhibiting signs or symptoms of infection or illness.
Standard thermal conditions characteristic of the on-site air-curtain burning option are likely to
destroy all potential microbial hazards (NABCC 2004; Schwarz et al. 2006; Berge et al. 2009;
Gwyther et al. 2011). Therefore, releases of pathogens to the environment are not anticipated and
modeling was not done for on-site air-curtain burning.
Only prions are expected to survive the typical thermal conditions associated with on-site open
burning. All other pathogens are expected to be destroyed during the burning process.
During the composting process, temperatures of at least 55°C (131°F) must be reached for three
or more days to inactivate microbial populations (NABCC 2004). During the first phase of the
composting process, the temperature at the core of the pile can reach 55-60°C (131-140°F)
within 10 days and remain in that temperature range for several weeks (NABCC 2004). Several
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
days of those temperatures in the compost pile is adequate to inactivate bacteria, viruses, and
protozoa (including their cysts/oocysts) (Franco 2002; Wilkinson et al. 2007; Berge et al. 2009;
Schwarz and Bonhotal 2014; Xu et al. 2007). However, the endospores characteristic of spore-
forming bacteria (e.g., Bacillus anthracis, Clostridium perfringens, and Coxiella burnetii) and
prions would not be inactivated. Thus, spore-forming bacteria and prions remain as potential
microbial hazards associated with composting.
Releases of pathogens are unlikely during the rendering, off-site lined landfilling, and off-site
fixed facility incineration options because all releases from these facilities are highly regulated.
These regulated facilities require the containment and treatment (e.g., chemical disinfection of
wastewater) to avoid pathogen releases. Concerns associated with exposure to prions during the
rendering process are well documented, and federal regulations are in place to prevent the
introduction of prion-contaminated materials in rendering byproducts (Meeker 2006). The
survival of prions following rendering is frequently noted as a serious drawback of this option
(Taylor et al. 1995; Meeker 2006). Upon further examination, other prion exposure pathways are
limited to occupational exposure to contaminated surfaces or materials (Meeker 2006).
Occupational guidance precludes worker exposure to prions in areas where outbreaks of
transmissible spongiform encephalopathies (TSEs) historically occurred (HSE 2007). This
guidance suggests that workers in rendering facilities wear appropriate personal protective
equipment (PPE), including gloves and a respirator. In the literature reviewed, there was no
evidence of prion release outside of rendering facilities, and it appears that their release is
unlikely. For these reasons, prions are not analyzed as a potentially hazardous biological agent
associated with rendering in this scenario.
Table 2.4.4 organizes the list of microbes likely to be associated with each type of carcass
management. Included in this list are six gram-positive bacteria, seven gram-negative bacteria,
three protozoa, six viruses, one fungus, and one prion type. These microbes have been identified
in a variety of livestock types, including swine, cattle, and poultry. Although the assumptions
described in Section 3 are primarily focused on the management of cattle and not on swine and
poultry, microbes associated with all livestock types are presented in Table 2.4.4. They are
potential hazards associated with the management of livestock carcasses during a natural
disaster.
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
Table 2.4.4. Microbial Hazards Possibly Associated with Each Option
Management
Specific
Microbes Potentially Released by Stage of Carcass Management
Type
Management
Storage, Transportation,
Carcass Management Options
Option
and Handling
Including Residuals
Combustion-
On-site Open
Bacillus anthracis;
Prions (PrPSc)4
based
Burning (pyre)
Campylobacter spp.;
Management
On-site Air-curtain
Clostridium perfringens;
None
Burning
Coxiella burnetii;
Off-site Fixed-
Dermatophilus congolensis;
None
facility Incineration
Escherichia coli 0157:H7
and other shiga-toxin
producing strains;
Leptospira spp.;
Listeria monocytogenes;
Mycobacterium avium
paratuberculosis;
M. bovis;
Salmonella spp.;
Shigella spp.;
Yersinia enterocolitica;
Cryptosporidium spp.;
Giardia spp.;
Toxoplasma gondii'.
Trichophyton verrucosum;
Rotavirus;
Hepatitis E virus;
Influenza A (avian influenza
virus;
Enteroviruses;
Adenoviruses;
Caliciviruses (e.g..
norovirus);
Prions (PrPSc)
Land-based
On-site Unlined
B. anthracis;
B. anthracis;
Management
Burial
Campylobacter spp.;
Campylobacter spp.;
C. perfringens;
C. perfringens;
Coxiella burnetii;
Coxiella burnetii;
Dermatophilus congolensis;
Dermatophilus congolensis;
E. coli 0157:H7 and other
E. coli 0157:H7 and other shiga-
shiga-toxin producing strains;
toxin producing strains;
Leptospira spp.;
Leptospira spp.;
L. monocytogenes;
L. monocytogenes'.
M. avium paratuberculosis;
M. avium Paratuberculosis;
M. bovis;
M. bovis;
Salmonella spp.;
Salmonella spp.;
Shigella spp.;
Shigella spp.;
Y. enterocolitica'.
Y. enterocolitica'.
Cryptosporidium spp.;
Cryptosporidium spp.;
Giardia spp.;
Giardia spp.;
T. gondii'.
T. gondii'.
4 In animals, prion diseases include scrapie of sheep and goats, bovine spongiform encephalopathy (BSE) of cattle, and chronic
wasting disease (CWD) of wild deer and elk. In humans, prion diseases include a group of fatal neurodegenerative and
infectious disorders such as Creutzfeldt-Jacob disease (CJD), a variant form of CJD (vCJD), Gerstmann-Straussler-Scheinker
syndrome (GSS), and kuru, fatal familial insomnia (FFI) (Prusiner 1996).
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
Management
Specific
Microbes Potentially Released by Stage of Carcass Management
Type
Management
Storage, Transportation,
Carcass Management Options
Option
and Handling
Including Residuals
Trichophyton verrucosum:
Trichophyton verrucosum;
Rotavirus;
Rotavirus;
Hepatitis E virus;
Hepatitis E virus;
Influenza A (avian influenza
Influenza A (avian influenza virus6);
virus);
Enteroviruses;
Enteroviruses;
Adenoviruses;
Adenoviruses;
Caliciviruses (e.g., norovirus);
Caliciviruses (e.g..
Prions (PrPSc)
On-site Composting
noro virus);
B. anthracis;
Prions (PrPSc)
C. perfringens;
Coxiella burnetii'.
Prions (PrPSc)
Off-site Lined
None
Landfill
Off-site Rendering
B. anthracis;
None
Material
Campylobacter spp.;
Processing
C. perfringens;
Coxiella burnetii;
Dermatophilus congolensis;
E. coli 0157:H7 and other
shiga-toxin producing strains;
Leptospira spp.;
L. monocytogenes;
M. avium Paratuberculosis;
M. bovis;
Salmonella spp.;
Shigella spp.;
Y. enterocolitica:
Cryptosporidium spp.;
Giardia spp.;
T. gondii'.
Trichophyton verrucosum;
Rotavirus;
Hepatitis E virus;
Influenza A (avian influenza
virus8);
Enteroviruses;
Adenoviruses;
Caliciviruses (e.g..
norovirus);
Prions (PrPSc)
While a large number of microorganisms are classified as fungi, only one is included in Table
2.4.4. The major fungal pathogens of humans (species of Aspergillus, Blastomyces, Candida,
Cryptococcus, Paracoccidoides, Pneumocystis, and various dermatophytes) are not necessarily
associated with livestock carcasses, even though there might be an increased risk of infection
associated with handling soil during carcass management activities (MacCallum 2014). All
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
microbes that can occur in healthy livestock are included as potential hazards in the on-site
unlined burial option, as well as the storage, transportation, and handling stages of carcass
management, because there are no initial assumptions on thermal conditions that would
inactivate any of the agents. While workers handling livestock carcasses are assumed to wear
PPE, the storage pile is uncovered and there are no strategies to mitigate the release of microbes
to the environment from the storage pile. With respect to the on-site unlined burial option, the
conditions of deep burial and associated pressures, oxygen levels, and temperatures might limit
the survival of the majority of non-spore forming organisms (NABCC 2004; Gwyther et al.
2011). However, empirical studies of livestock burial sites have reported the detection of
pathogenic bacteria including Escherichia coli, Clostridiumperfringens, and Salmonella spp. in
groundwater and near-by soil samples (Davies and Wray 1996; Joung et al. 2013). Although the
number of samples that tested positive for the presence of these pathogens was low, pathogens
were detected at sampling sites 0-50 m (0-164 ft), 51-100 m (167-328 ft), and 101-200 m
(331-656 ft) from the burial site, which contained a mixture of carcasses including pigs, cattle,
goats, and deer. In consideration of these data, all identified microbes are considered capable of
surviving the burial process.
1.5, Expert Workshop at the 5th International Symposium on Animal Mortality
Management
From September 28 through October 1, 2015, the 5th International Symposium on Animal
Mortality Management5 in Lancaster, Pennsylvania, brought together experts from academia,
government, and the private sector to share information on a range of topics relating to livestock
carcass management. The authors of this report held a workshop on the final day of the
symposium to obtain input from experts on the proposed methods, data, and assumptions for the
exposure assessment of livestock carcass management following a natural disaster. The objective
of the expert workshop was to obtain real-world feedback and recommendations from livestock
carcass management researchers and practitioners.
At the time of the expert workshop, a detailed conceptual model and analysis plan had been
developed for the natural disaster scenario exposure assessment, but the assessment had not been
5 The symposium program and proceedings are available for download at: http://animalmortmgmt.org/svmposium/proceedings-
of-the-5th-international-svmposium-on-animal-mortalitv-management/
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
performed. The conceptual model and analysis plan described specific assumptions about the
carcass management options and identified data sources and models that would be used to
estimate exposures. Therefore, the workshop allowed for a timely review by the experts and an
opportunity to refine the approach before its implementation.
Twenty-eight experts attended the three-hour workshop. It began with an introduction about the
exposure assessment project, including its impetus, scope, and objectives. The remaining time
was divided between two technical sessions. The first session covered the exposure assessment
for the four on-site carcass management options. For each management option, the authors
summarized assumptions that would affect the nature and magnitude of potential chemical and
microbial exposures, including:
¦ The design (e.g., pyre size, construction, fuels) and implementation (e.g., burn duration,
temperature) of the option
¦ Expected releases and exposure pathways
1 Chemicals and microbes of concern
A group discussion followed the presentation for each management option.
The second technical session addressed potential sources of exposure associated with carcass
handling and transportation activities. At the time of the workshop, those activities had not been
included in the scope of the assessment. The authors posed a series of questions intended to build
conceptual models, identify potential releases and exposure pathways, and identify useful
information sources or assumptions for carcass handling and transportation.
Following the workshop, the project team met to review the meeting notes, as well as
publications and other follow-up information provided by experts, to identify refinements to the
exposure assessment analysis plan. Although the experts identified no major deficiencies of the
analysis plan, they suggested refinements to some assumptions. The expert discussion also leads
to the addition of carcass transportation and handling to the scope of the assessment. Several
specific refinements and additions based on the expert workshop are listed below:
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
¦ For air-curtain burning, the fuel to carcass ratio was increased from 2:1 to 4:1. This change,
which increases emissions from that management option, was based on field experience
where combustion efficiency was limited by rain and use of low-quality wood fuel.
¦ For air-curtain burning, the burn duration was increased from 25 hour (hr) to 48 hr. The
experts found the previous assumption too optimistic.
¦ Although carcasses should be transported in "leak-proof' containers, the experts agreed that
vehicles designed to be leak-proof rarely are. Therefore, it is common practice to use a
double lining of plastic and layered absorbent carbon material as added leak protection
during transportation.
¦ The experts recommended an assumption that trucks will be loaded to no more than 60%
capacity by volume because the carcasses might bloat and expand after loading.
¦ For carcass transportation and handling scenarios, the experts noted that abdomens typically
burst within 3 or 4 days after death, with liquid releases occurring 3 to 7 days after death.
These events are likely to occur during the management action in our scenario based on the
assumed timing sequence of events.
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
3. 4 'or«ceptual Models of Carcass Management Options
This section provides a conceptual model for each of the assessed management options,
including carcass management processes and equipment, waste and other products (e.g., ash,
finished compost) and their characteristics, releases to environmental media (i.e., air, water, soil),
and exposure pathways. As discussed in Section 2, exposures are not quantified for the three off-
site management options (i.e., landfilling, incineration, rendering), because all releases to the
environment from those facility categories are from pollution control systems that should comply
with applicable requirements. Exposure to pathogens that might survive the rendering process is
assumed to be outside the scope of this assessment for natural disasters (see Section 2.4.2 for
more details).
This section also describes estimated chemical release rates from the four on-site management
options: open-pyre burning (Section 3.1), air-curtain burning (Section 3.2), unlined burial
(Section 3.3), and composting (Section 3.4). Quantitative estimates of microbial releases to the
environment could not be based on direct evidence of the concentration of microbes present in
livestock at the time of management. Instead, the concentration of microbes present in cattle
manure or a concentration less than the infectious dose were used as an estimate of microbes
released to the environment. This is reasonable because environmental factors over time are
equally likely to promote or to limit microbial growth and reproduction from the animal's time of
death until the microbes' release into the environment. The qualitative potential for microbial
releases and exposures from these management options are discussed in Section 6.
Sections 3.1 through 3.5 include diagrams of the conceptual models to show how chemicals and
microbes are released during each option, including the management of residuals (e.g.,
application of finished compost, disposal of combustion ash). The diagrams also identify the
exposure pathways that chemicals and microbes might follow through the abiotic and biotic
media to potential receptors and chemical fate and transport processes (e.g., wet and dry
deposition, erosion, bioaccumulation) in abiotic and biotic media. These diagrams are products
of a conceptual modeling phase of the project that followed initial problem formulation.
Presented along with the conceptual models in this section are summaries of scientific literature
that support quantitative modeling of releases, fate and transport, and exposure. For example,
emission factors are presented for carcass incineration as milligrams chemical emitted per
26
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
kilogram carcasses incinerated, and the models consider concentrations of chemicals in leachate
measured at the bottom of experimental carcass burial pits.
Appendix C presents further details about the conceptual models for this project. In the appendix,
the conceptual models are presented at two levels of detail. First, the conceptual model for each
management option, including the three off-site options, is presented in a single, overview
diagram. A more-detailed second set of conceptual model diagrams provides further information
about the sources, transport, and fate processes. The second set is divided into a series of
modules and includes one module for each management option, one module for each type of
abiotic exposure medium, and several biological modules to represent food chain transfers and
ultimate exposures of humans, livestock, and wildlife.
3.1. Carcass Transportation and Handling
All of the livestock carcass management options involve transportation and other handling of the
carcasses. Carcass transportation and handling activities considered in the assessment occur
between animal death and placement of the carcasses in the management units (e.g., burial
trench, compost windrow); these activities include the following:
¦ Moving the carcasses from the place of death to a temporary storage location
¦ Storage of the carcasses temporarily until transportation and management options are ready
1 Loading the carcasses onto vehicles for movement to the management location
¦ Transporting the carcasses in multiple truck loads
1 Unloading and placing the carcasses at the management location
USDA's APHIS National Animal Health Emergency Management System guidelines (e.g.,
USD A 2013b) provide various on-site biosecurity measures to limit exposures of livestock and
response personnel, particularly to FAD agents. For example, biosecurity zones should be
established at the farm for decontamination of equipment and vehicles. For the exposure
assessment for the natural disaster scenario in which FAD agents are not a consideration,
biosecurity precautions are assumed to include only the use of PPE and implementation of the
management options consistent with best practices and applicable regulations.
This section describes the nature and scope of carcass transportation and handling activities
included in the assessment. In most respects, these activities are independent of the carcass
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
management option; that is, the potential exposures are the same for each of the management
options. Table 3.1.1 summarizes the scoping assumptions for carcass transportation and handling
in the exposure assessment. The assumptions are discussed further in Sections 3.5.1 through
3.5.3.
Table 3.1.1. Summary of Assumptions for Livestock Carcass Transportation and Handling
Activity
Scoping Assumptions Carcass Transportation and Handling
Carcass Handling
¦ Workers wear PPE, including coveralls, gloves, boots, and masks.
¦ Non-workers do not touch or otherwise contact carcasses, and the public would be
excluded from work sites based on general safety concerns.
¦ Biosecurity zones and associated biosecurity practices required for foreign animal
disease outbreaks are not used.
Temporary Carcass
Storage
¦ Carcasses are moved from the mortality location to an outdoor pile on bare earth
where they stay for 48 hr before on-site or off-site management.
¦ The pile lias a trapezoidal cross sectional shape that is 8 ft (2.4 m) wide at the base, 3
ft (0.91 m) wide on top, and 5 ft (1.5 m) high With a total volume of 196 yd3 (150
m3), the length of the pile is 132 ft (40.3 m).
¦ No disinfectants or other chemicals are applied to the pile.
Carcass Transportation
¦ Carcasses are transported in roll-off trucks with a weight capacity of 12 tons or 24,000
lb (10,886 kg) and a volume capacity of 40 yd3 (31 m3).
¦ Carcasses are transported in roll-off trucks with water-proof liners to minimize
leakage.
¦ Tarps cover the carcasses.
¦ Eight truck trips are required to move all carcasses
¦ Twenty liters (20 L) of carcass fluids leak per trip per truck
¦ On-site transportation methods are equivalent to off-site transportation methods.
Abbreviations: PPE = personal protective equipment; hr = hr; ft = feet; lb = pound (weight); yd = yard.
1.5.1. Carcass Handling Before and after Transportation
Moving carcasses to and from the storage pile, loading and unloading vehicles, and placing the
carcasses in a management unit might require workers to come in contact with the carcasses
(e.g., particularly smaller livestock such as pigs or poultry). As shown in the conceptual model in
Figure 3.1.1, these activities could lead to primary- and secondary-contact exposures through
dermal exposure, inhalation, or hand-to-mouth transfer of particles that subsequently are
ingested. The assessment assumes workers are the only humans with direct access to the
carcasses. Animals that are likely to contact temporarily stored carcasses include scavenging
wildlife (e.g., fox, crow, rats) and insects (e.g., flies).
28
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
Particles and vapors
Incidental
Ingestion;
Dermal
Inhalation
Humans
Air
Figure 3.1.1. Conceptual model for exposure pathways from livestock carcasses handling.
Without PPE, such as gloves, boots, or respiratory protection, workers directly contacting
carcasses might inhale chemicals or microbes emitted to the air from the carcasses or might
accidently ingest some of the liquids released by decomposition. Assumptions about the use of
PPE are based on regulations of the Occupational Safety and Health Administration (OSHA),
specifically Appendix B of 29 Code of Federal Regulations [CFR] 1910.120. These regulations
define required and optional equipment for four levels of protection that can be chosen based on
the potential hazards expected for a job. The exposure assessment assumes use of Level-D PPE,
which is the least stringent of the four levels and includes:
Required, included in the exposure assessment for the natural disaster scenario:
¦ Coveralls
¦ Boots/shoes, chemical-resistant steel toe and shank
Optional, included for the exposure assessment for the natural disaster scenario:
¦ Gloves
¦ Safety glasses or chemical splash goggles
¦ Dust mask or escape mask
Optional, not included in the exposure assessment for the natural disaster scenario:
¦ Boots, outer, chemical-resistant (disposable)
¦ Hard hat
¦ Face shield
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
This level of PPE is intended to preclude splashes, immersion, or the potential for unexpected
inhalation of or contact with hazardous levels of any chemicals (29 CFR 1910.120 Appendix B).
While dust masks would not necessarily provide protection against air-borne chemicals, the
potential for acute effects level inhalation exposure is assumed to be negligible because of the
passive nature of the emissions and an adequate fresh air supply for outdoor activities. For indoor
activities, building ventilation systems would limit chemical exposure. Moreover, the duration of
the exposure during handling would be on the order of hours. Workers and farm residents are not
expected to be in close proximity to the source for an extended period. That is, their potential
inhalation exposure is limited to only what they breathe in when they are in close proximity to
the carcasses. Therefore, concentrations of chemicals in air would be of concern if they exceeded
acute health effects levels. Accordingly, exposures from carcass handling are assumed to be
adequately mitigated and are not included in the quantitative assessment.
1,5,2, Temporary Carcass Storage Before Transportation
Temporary on-site storage of carcasses is likely to be necessary while available management
options are identified and evaluated, while on-site management units are constructed, and while
awaiting transportation or completion of other logistical requirements (e.g., obtaining burn
permits, obtaining air-curtain burning equipment from off-site). Many state regulations require
carcasses to be managed within a specified timeframe, usually within 24 to 72 hours (USDA
2015). For the exposure assessment, on-site storage for 48 hours (2 days) is assumed for all
management options.
The location and design of the temporary carcass storage location(s) can affect potential
exposure pathways. Carcasses could be stored in a pile on the ground in open air, in a
refrigerated storage unit, or in containers (USDA 2015). Carcasses on the ground could be
covered with a tarp, soil, or other material, or left uncovered (USDA 2005). Carcasses might be
placed on bare earth or on an impervious surface with or without leachate collection or other
management features. For the natural disaster scenario, in which the livestock are neither
diseased nor contaminated with elevated levels of chemicals (e.g., pesticides) or radiological
agents, it can be assumed that no special precautions are necessary to contain the carcasses.
Temporary storage is, therefore, assumed to occur in a pile on the ground outside without a liner
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
or tarp covering even though the sight of carcasses and odor of volatiles may cause distress in
some individuals.
The dimensions of the storage pile are based the total amount of carcasses (i.e., 45,360 kg = 50
U.S. tons), the assumed volume of a single cattle carcass (1.5 m3) from South Australia
Environmental Protection Agency (SAEPA 2016), 100 carcasses each weighing 2,268 kg (1,000
lb). The pile is assumed to have a trapezoidal cross sectional shape that is 2.4 m (8 ft) wide at the
base, 0.91 m (3 ft) wide on top, and 1.5 m (5 ft) high. With a total volume of 150 m3 (196 yd3),
the length of the pile is 40.3 m (132 ft).
Figure 3.1.2 presents the conceptual model for the temporary carcass storage pile. Chemical
releases from the storage pile include volatilization of particles and vapor to air, and leaching of
liquid from the pile to the ground below. There were no sources reporting the concentrations or
emission factors for chemicals released to air from uncovered, aboveground carcasses. Young et
al. (2001) described the degradation process for buried carcasses in comparison to the stages of
decomposing putrescible materials in a domestic landfill. The first two stages, which are most
likely to occur during the two-day carcass storage, include:
1) Initial aerobic phase. Degradation by aerobic microbes, for which oxygen provides
electron receptors with production of carbon dioxide, progresses rapidly until
available oxygen is depleted internally, and further aerobic microbial activity is not
possible. Changes within the body tissues within the first day or so after death prevent
the growth of aerobic bacteria, except on the surface of the carcass where it is
exposed to the atmosphere.
2) Initial anaerobic phase. Bacterial heterotrophs reduce sulfates and nitrates and begin
the breakdown of long chain lipids and carbohydrates, which also releases carbon
dioxide and water. Proteins are degraded through amino acids to ammonium.
Hydrogen sulfide and other odor-causing chemicals also can be formed in Phase 2.
Young et al. (2001) concluded that the initial stage of intense decomposition may produce
significant volumes of carbon dioxide and, possibly, malodorous gases, but the amount of
methane is likely to be limited until later stages of decomposition.
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
Sources that discuss air quality from livestock composting generally focus on odor generation
and vapors including hydrogen sulfide and ammonia. Glanville et al. (2006), for example,
reported that odor levels within the first four months of composting were similar to those
reported for pond water (200-300 odor detection threshold [ODT], the volumetric ratio of fresh
air to sample, are at the lowest level that olfactometry panelists could detect an odor). The levels
are quite low compared with manure-related facilities (4,000 ODT).Carcass management
workers are those most likely to be exposed to gases from the storage pile. Their exposure to
gases from the storage pile would be no longer than the duration of storage (48 hr). Workers and
farm residents are not expected to continually be in close proximity to the source throughout that
period. Therefore, concentrations of chemicals in air would be of concern if they exceeded acute
health effects levels. Placement of a storage pile outdoors is expected to prevent its ambient
concentrations of airborne chemicals from reaching harmful levels.
Any non-volatilized liquid leaching from the storage pile is assumed to percolate down through
soil to the groundwater aquifer. The exposure assessment includes modeling chemical fate in the
subsurface soil and in groundwater, with chemicals reaching a drinking water well 30.5 m (100
ft) downgradient. If chemical concentrations in groundwater as drawn by the well for household
uses are near human welfare benchmarks of concern, livestock exposures via groundwater will
be assessed. Otherwise, the latter pathway will not be assessed; the much higher minimum
groundwater flow required to water 50 tons of livestock would dilute contaminants a further
three to four orders of magnitude compared with the concentrations estimated for a low-flow
aquifer providing sufficient water for household uses.
1,5,3, Carcass Transportation
Many equipment options are available for moving the carcasses, and assumptions about which
types of equipment are used affect potential release pathways and the rates of release of
chemicals and microbes. For off-site management options, where carcasses are transported over
public roads, decisions about livestock carcass vehicles and equipment are guided, to some
extent, by federal regulations (9 CFR 325.20 and 325.21), which require all vehicles used to
transport dead, dying, disabled, and diseased livestock or parts of livestock carcasses to be leak-
proof and constructed to permit thorough cleaning and sanitizing. Along with federal regulations,
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
local and state regulations exist that prescribe the transportation of carcasses on public roads,
however, only federal regulations are considered for this assessment.
Particles and Vapors
Leakage to soil
Stomatal
Uptake
Terrestrial
Plants
Uptake,
bioaccumulation
Leaching and
Sorption to
Subsurface Soil
Surface Water
Recharge
Sedimentation,
Resuspension, &
Diffusive Exchange
Aquatic
Life
Inhalation
Uptake,
bioaccumulation
Livestock
Ingestion
Ingestion &
Inhalation
Ingestion
Ingestion
Humans
Inhalation
Air
Well
Water
On-site Lake
Sediment
Soil
Groundwater
Storage Pile
Figure 3.1.2. Conceptual model for exposure pathways from temporary carcass storage.
Figure 3.1.3 presents the conceptual model for chemical and microbial releases from carcass
transportation. Potential release pathways include airborne releases from the exposed carcasses
during transit, body fluid leakage from the truck bed, and spillage of carcasses and leaked body
fluid in the event of an accident. The potential for these releases to occur and their estimated
magnitude depend on the types of equipment (e.g., vehicle type, covers) assumed.
The University of Minnesota Center for Animal Health and Food Safety (UM-CAHFS 2014)
identified three types of trucks that are commonly used to transport livestock carcasses:
¦ Rendering truck - A "rendering" truck is a semi-truck that has an attached box trailer. It has
a leak-proof, sealed bed, and an open top. The length of trailer can vary, however the most
common bed lengths are 28, 32, and 40 ft (8.5, 9.8, and 12.2 m). The weight capacities and
lengths for a rendering truck are 40,000, 45,000, and 50,000 lb (18,144, 20,412, and 22,680
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
kg) for 28, 32, and 40 ft bed lengths respectively (UM-CAHFS 2014). These trucks can
transport carcasses from farms to off-site facilities.
Particles and vapors
Routine Leakage,
Accidental Cargo
Spillage
Stomatal
Uptake
Terrestrial
Plants
Inhalation
Ing
Livestock
Ingestion
Incidental
Ingestion;
Dermal
Ingestion
Humans
Air
Soil
Inhalation
Figure 3.1.3. Conceptual model for exposure pathways from livestock carcass
transportation.
¦ Roll-off truck - A roll-off truck has a removable, open-top container with wheels that allow
it to be rolled off of the truck onto the ground. Roll-off containers are available in different
sizes, including 10, 15, 20, 30, and 40 yd3 (7.6, 11.5, 15.3, 22.9, and 30.6 m3). Roll-off
containers are not designed to be leak-proof, and additional measures (e.g., lining with a
double layer of plastic sheeting) are often used to reduce the likelihood of leakage (UM-
CAHFS 2014).
¦ Dump truck - A dump truck is an open-bed truck that has a hydraulic system to lift the front
of the bed to allow the contents to dump out of the back of the truck. This truck does not
necessarily come with a sealed tailgate nor is it considered leak-proof. Additional
modification measures would be required to make a dump truck resist leakage. Dump trucks
are available in various capacities, and include single- and tandem-axle vehicles. A tandem-
axle dump truck typically has a volume capacity of approximately 15 yd3 (11.5 m3) and a
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
weight capacity of approximately 40,500 lb (18,370 kg) (UM-CAHFS 2014). The weight
capacity of a dump truck can also vary by road weight limit.
The rendering truck is the only one of these truck types that is by definition considered already
leak-proof. However, for the Phases 1 exposure assessment, carcasses are not diseased and
timely access to available vehicles is likely to be a priority. Therefore, a lined roll-off truck with
a weight capacity of 12 U.S. tons or 24,000 lb (10,886 kg) and a volume capacity of 40 yd3 (31
m3) is used for both on-site and off-site management options (CWS undated). Although lining of
the truck is not required, a liner is assumed to comply with regulations at 9 CFR 325.20 and
325.21 as a means of meeting the leak-proof requirement.
Assuming that the volume of an adult bovine carcass is 1.5 m3 based on SAEPA (2016), the total
volume of carcasses to be transported for any of the management options is 150 m3. The number
of truck trips required to transport the carcasses may be limited by either the volume or weight
capacity of the roll-off truck. As stated above, the truck is assumed to have a weight capacity of
10,886 kg and a volume capacity of 31 m3. In addition, carcass management experts suggest (see
Section 2.5) that trucks and other containers should not be filled to capacity with carcasses
because the carcasses may expand after loading. Specifically, the experts stated that standard
practice is not to surpass 60% of the volume capacity for each load. Thus, the effective volume
capacity per load is 60% of 31 m3, or 18.3 m3. The volume capacity per load is reached before
the weight capacity, and eight truck trips are required to transport all the carcasses.
According to information provided at the expert workshop (see Section 2.5), even leak-proof
containers are "almost never leak-proof." Therefore, a double lining of plastic and layered
absorbent carbon material are often added precautions, particularly for carcasses of diseased
animals. The only information available to quantify leakage is UM-CAHFS (2014). Based on
consultations with rendering industry experts, the authors reported the rate of leakage from a
fully loaded standard rendering truck to be around 20 L per load. No quantitative information has
been found to compare this estimate to the effectivenss of liners or other practices used to make
other truck types comply with the FHWA "leak-proof' requirement of 9 CFR 325.21. This rate
of leakage (i.e., 20 L) is assumed for each truckload for all management options.
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
A tarp covering is assumed for all truck transportation in the exposure assessment. A tarp
covering is routinely used during carcass transportation to restrict contents from visibility or
ejection (UM-CAHFS 2014). Although not required by federal regulation, tarps may be required
under a state regulation or rule. Tarps can be waterproof (e.g., waterproofed canvas, vinyl coated
polyester mesh), but they are not airtight. They can be secured manually (e.g., with bungee
cords) or with a mechanical tarp roller if the truck is equipped with one. The effectiveness of the
cover is affected by the type and condition of tarp, the type of securing method, the form and
condition of the cargo, freeboard space between the cargo and top of the truck, weather (e.g.,
wind temperature), and vehicle speed.
If a truck carrying carcasses gets into an accident en route to an off-site carcass management
facility, hazardous agents may be released to the ground or air. The likelihood of an accident can
be evaluated with accident statistics for large trucks (i.e., gross weight at least 10,000 lb [4,536
kg]) from the US Department of Transportation (USDOT) for 2013, the most recent year with
data available (USDOT 2015). Large trucks traveled 275,018 million miles (442,597 million km)
in the United States in 2013, and approximately 327,000 accidents involving large trucks were
reported to the police. Based on this information, there were 0.74 accidents reported to the police
per million km traveled (1.2 accidents per million miles traveled), or a risk of 7.4 E-07 risk of an
accident per km traveled.
A truck accident involving a load of livestock carcasses would be of concern for the exposure
assessment only if the cargo spills from the truck. The accident statistics discussed above are for
all accidents reported to the police, not necessarily ones that included spillage. However,
available statistics indicate that cargo was spilled in 12% of the accidents in 2013 involving
trucks that carried hazardous waste. If it is assumed that this rate of accident spillage for trucks
carrying hazardous waste is the same as the rate of spillage for all large truck accidents, then the
risk of an accident with spillage per km traveled is 8.9 E-08 (= 7.4 E-07 x 12%).
The likelihood that an individual truckload is involved in an accident with spillage depends on
the distance traveled to the management location. If the average distance traveled per truck trip is
assumed to be 100 km, then the risk of an accident with spillage per truck load is 8.9 E-06 (= 8.9
E-08 x 100 km), and the risk for eight truck loads is 7.1 E-05. This analysis indicates a low
likelihood of carcasses being released as a result of an accident during transit to an off-site
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
management facility. Moreover, if an accident were to occur and carcasses were released directly
to the ground, response actions would be taken quickly to remove the carcasses and associated
wastes. Based on the calculated low rate of accidents with spillage occurring, and the limited
extent and duration of any releases, exposure pathways associated with truck accidents are not
included in the quantitative assessment.
3,2. On-site Open Burning (Pyre)
An overview of the conceptual model for the on-site open burning (pyre) management option is
presented in Figure 3.2.1, and further assumptions for open burning are provided in Table 3.2.1.
With this option, the carcasses are burned in a single pyre resulting in release of gases and
particles, including active or inactivated microbes, over the course of an assumed 48-hr burn
duration (USDA 2005). Ash may be managed on site or removed to an off-site landfill. For this
exposure assessment, the ash is managed on site, specifically by being buried or covered with
clean soil in place (i.e., over the area of ground on which the pyre burned). The fuels used to
promote burning of the carcasses also will release some chemicals in vapor and particulate-phase
to air while leaving other chemicals in the residual ash. Particles released to air can include
microbes and can cover a range of sizes from submicron (less than 1 micrometer [|im]) to a few
millimeters (mm) in length or diameter.
There are no sources directly reporting measurement of combustion temperatures within carcass
pyres. Based on information on the ignition and combustion temperatures of wood and coal
reported by Bartok (2003), 550°C (1,022°F) is the temperature assumed for this assessment.
There is likely to be a significant temperature gradient within a pyre, however, with portions near
the center of the pyre being significantly higher than the average temperature. Other portions,
particularly near the edges of the pyre or near wetter materials, are likely to be significantly
lower in temperature than the average.
Section 3.2.1 discusses chemicals released to air from open burning, and Section 3.2.2 discusses
possible releases from buried ash from percolation of rainwater through the ash layer.
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
On-site Transportation
Combustion
Burial of ash
in place
Wet & Dry Particle
Deposition;
Diffusive Vapor
Exchange
Wet & Dry
Deposition
Particle
Deposition,
Stomatal Uptake
Erosion
& Runoff
Terrestrial
Plants
Root uptake
Uptake,
bioaccumulation
Aquatic
Life
Leaching
Sedimentation,
Resuspension, &
Diffusive Exchange
Surface Water
Recharge
Inhalation
Uptake,
bioaccumulation
Incidental
Ingestion
Ingestion
Livestock
Ingestion
Ingestion &
Inhalation
Ingestion
Ingestion
Humans
Inhalation
Air
Soil
On-site Lake
Sediment
Groundwater
Well
Water
Figure 3.2.1. Conceptual model of exposure pathways from on-site open burning of
livestock carcasses.
1.5.1. Releases of Combustion Products to Air
Chen et al. (2003, 2004) studied emissions of PAHs and metals from different types of
incinerators, including a hog farm waste incinerator (HOWI), which burned at 255-595°C with
unrefined methane gas as the auxiliary fuel, and a livestock disease control incinerator (LIWI),
which burned at a higher temperature (755-891°C) fueled by diesel fuel. The temperature
assumed for open-pyre burning (550°C) is most similar to the HOWI studied by Chen and
colleagues.
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
Table 3.2.1. Source and Exposure Pathway Assumptions for On-site Open Burning
Management Option
Conceptual Model
Feature
Assumptions
Pyre Design and Use
¦ Based on pyre construction guidelines provided by USDA (2005), 45,359 kg (50
tons) of carcasses are burned in a single pyre that is 2.4 m (8 ft) wide by 91.4 m (300
ft) long.
¦ Fuels used in construction of the pyre include: 300 hay bales, 300 timbers (8 ft by 1
ft2 (2.4 mby 0.30 mby 0.30 m) each 50 lb (22.7 kg) kindling, 10,000 lb (4,536 kg)
coal, and 100 gal (378.5 L) fuel oil (USDA 2005).
¦ Combustion is complete within 48 hr (USDA 2005).
¦ The combustion temperature is 550°C (1022°F).
¦ After combustion, the ash is buried in place. Cover depth is sufficient to place ash
below the root zone.
Air Pathways
¦ Inhalation of particulate matter and vapor-phase gases by humans is assumed to be at
point of maximum concentration.
¦ Humans also might inhale airborne microbial particles or aerosols.
¦ Downwind air concentrations of vapor-phase chemicals could be absorbed by plant
leaf stomata.
¦ Downwind air deposition of particulate-phase chemicals and microbial particles to
the top surfaces of leaves are unlikely to result in absorption of chemical or
internalization of microbes.
¦ Reference air concentrations to protect individual humans should also be protective of
mammalian livestock. Therefore, inhalation by livestock is not assessed (USEPA
2005a).
Soil Ingestion
Pathways
¦ Potential ingestion pathways associated with surface soil include incidental soil
ingestion by humans and livestock, erosion and runoff to the lake and uptake by
aquatic animals, and plant absorption of chemicals from soils, with subsequent
ingestion by humans and livestock.
¦ Chemicals deposited from air to soil near the source are primarily particulate-phase
and are distributed in the top two centimeters of surface soil; leaching to deeper soils
is limited and not evaluated.
¦ A fraction of chemicals deposited to surface soil will run off or erode to the on-site
lake.
¦ Fanning, livestock pasturing, and grazing will not be performed on the pyre site until
after revegetation with grasses or cover crops that appear healthy.
Groundwater and Well
Water
¦ The water table is assumed to be 1 m (~ 3 ft) below the surface.
¦ An on-site groundwater well 30.5 m (100 ft) downgradient from the pyre site is used
for drinking water. Well water serves farm residents. Livestock drinking well water is
assessed only if concentrations estimated for low-flow aquifers sufficient to supply
one household indicate possible concern (see Section 3.1.2).
¦ Leaching to groundwater is assumed only for the ash burial; leaching following air
deposition to the agricultural field is unlikely to contribute substantially to
groundwater concentrations.
¦ Groundwater is not treated before use.
¦ Non-ingestion exposure to humans from well water could include inhalation of
aerosolized/volatilized agents; however, exposures via that pathway would be less
39
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
Conceptual Model
Feature
Assumptions
than via direct ingestion with the possible exception of trapped methane gas or
ammonia.
Surface Water,
Sediment, and Aquatic
Life
¦ Incidental ingestion and dermal exposure from recreational activities on or in the on-
site lake are possible, although not included in the conceptual model diagram or the
scope of the exposure assessment.
¦ Ingestion of recreationally caught fish occurs.
Production of Food on
the Farm
¦ Residents of the farm consume farm-grown plants.
¦ Livestock also consume farm-grown plants, then humans consume livestock products
(e.g., meat, milk, eggs).
Abbreviations: USDA = U.S. Department of Agriculture; ft = feet; lb = pound; gal = gallon; hr = hour; USEPA = U.S.
Environmental Protection Agency.
Emission factors (EFs) for low-, medium, and high-molecular weight PAHs and for metals
released from hog carcasses are shown in Tables 3.2.2 and 3.2.3, respectively. Methane
combustion alone should produce minimal PAHs and no metals; hence all of the PAHs and
metals reported for hog incineration with methane are assumed to have originated from the
carcass combustion. Chen et al. (2003, 2004) did not analyze emissions for dioxins, mercury, or
arsenic.
Table 3.2.2. Emission Factors for PAHs from HOWI Incinerator Carcass Burning (mg/kg
carcass)3
Waste Stream
Total PAHs
LM PAHs
MM PAHs
HM PAHs
Stack Flue Gas
285.0
235.0
34.7
15.6
Abbreviations: PAHs = polycyclic aromatic hydrocarbons; HOWI = hog farm waste incinerator; LM = low molecular weight;
MM = medium molecular weight; HM = high molecular weight.
a Based on Chen et al. (2003), Table 5. Total PAHs are based on the sum of 21 PAH species. Low-, medium-, and high-molecular
weight groups include two- and three-ringed PAHs (LW), four-ringed PAHs (MM), and five-, six-, and seven-ringed PAHs
(HW), respectively.
Table 3.2.3. Emission Factors for Metals from HOWI Hog Carcass Incineration (mg/kg
carcass)
Waste Stream
Fe
Cd
Cr
Cu
Mn
Ni
Pb
Zn
Stack Flue Gas (vapor-phase)3
11.32
0.03
0.37
0.20
0.16
0.47
0.47
0.49
Bottom Ash (particle-phase)1'
11.7
0.31
5.46
23.1
2.34
8.07
1.33
2.32
Abbreviations: HOWI = hog farm waste incinerator.
a Based on Chen et al. (2004), Table 4, HOWI.
Appendix A describes how compound-specific exposure factors (EFs) were estimated for PAHs
based on the data reported by Chen et al. (2003). The profile of individual PAHs released from
hogs burned with methane (Chen et al. 2003) and from poultry burned with wood in an air-
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
curtain burner (USEPA 2013a) are similar (Appendix Table A.l), with releases of naphthalene
approximating 50% of the total and 3- and 4-ringed PAHs predominating in the remaining
emissions.
To estimate total emissions from open-pyre burning of livestock carcasses, emissions of
materials that originated from the fuels used to burn the carcasses must be added to the emissions
from carcasses alone. Table 3.2.4 lists the quantity of each type of fuel needed for open-pyre
burning of large carcasses totaling 45,359 kg (50 U.S. tons) calculated from information
presented by the USDA (2005).
Table 3.2.4. Fuel Mass Used for Open-Pyre Burning and Quantity of Ash Remaining
Waste Stream
Assumptions
Material
Mass (kg)
Ash
Percent
(%)
Ash Mass
(kg)
Carcasses
100 carcasses; 1,000 lb (453.6 kg) each
45,359
6
2,722
Heavy Timbers
3 timbers per carcass (8 ft3 or 0.23 m3 each)3
500 kg/m3 per railroad tieb
34,000
1
340
Kindling
50 lb (22.7 kg) per carcass3
2,300
1
23
Straw Bales
3 bales per carcass3
20 kgperbaleb
6,000
1
60
Coal
100 lb (45.4 kg) per carcass3
4,536
2
91
Gasoline
1 gal (3.79 L) per carcass3
—
0
0
Total
3,236
Abbreviations: lb = pound; ft = feet; ft3 = cubic foot; gal = gallon.
a USDA (2005)
b Watkiss and Smith (2001).
In addition to air emission of PAHs, metals, and other chemicals per kg of carcass burned, there
are emissions per kg from timbers, kindling, straw, coal, and diesel added to estimate total
emissions from open-pyre burning. Watkiss and Smith (2001) reviewed EFs published for
domestic combustion sources including coal, wood, and straw, and data from crematoria to
estimate likely emissions from the open-pyre burning of livestock during the 2001 outbreak of
foot-and-mouth disease (FMD) in the United Kingdom. Toward the end of the outbreak, Watkiss
and Smith (2001) compared the chemical-specific EFs from the literature with measurements
made at actual pyres and with dispersion modelling. They used their dispersion modelling to
match measured values, where available. Table 3.2.5 lists the final EFs, per kg material burned,
estimated by Watkiss and Smith (2001). They were unable to estimate dioxin production by type
of material burned, but they estimated total dioxin release from all materials in a pyre in
41
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
collaboration with outside experts (Coleman and Foan, NAEI & EA, personal communication
2001 to Watkiss and Smith, 2001).
Table 3.2.5. Emission Factors to Air for Open-Pyre Burning by Material Burned (weight
chemical/weight material burned)3
Fuel
Benzo(a)
pyrene
(mg/kg)
Dioxins
(Mg/kg)
PMio
(g/kg)
NOx
(g/kg)
SO2
(g/kg)
CO
(g/kg)
HC1
(g/kg)
Coal
1.5
na
49.57
1.42
20
45.0
2.35
Wood (sleepers)b
1.3
na
7.9
0.72
0.037
99.3
1.175
Wood (kindling)
1.3
na
7.9
0.72
0.037
99.3
1.175
Straw
7.2
na
5.0
2.32
0.037
71.3
na
Diesel oil
na
na
0.25
2.16
2.8
0.24
0.01
Carcasses
7.2
na
10
4.63
1.4
142.6
0.7
Combined material
ne
1.0
ne
ne
ne
ne
ne
Abbreviations: PMio = particulate matter 10 micrometers diameter or smaller; na = not available; ne = not estimated.
a Based on Watkiss and Smith (2001) Table 3. Units vary by chemical.
b In the U.S., "sleepers," as they are called by Watkiss and Smith (2001), are usually referred to as "railroad ties."
Appendix A presents PAH congener-specific EFs to air for the quantities of each estimated to be
released from carcasses, wood (and kindling), coal, and straw in Table 3.2.4. Emissions for each
congener were estimated from emissions of benzo[a]pyrene reported by Watkiss and Smith
(2001) assuming that the PAH emissions profile measured for each type of material burned could
be indexed to benzo[a]pyrene emission rates. Table A.3 in Appendix A documents the derivation
of congener-specific PAH EFs from carcasses only for open-pyre burning. Table A. 5 documents
the derivation of congener-specific PAH emissions from wood/kindling added to the pyre, while
Table A.8 presents EFs for PAHs from the coal added to the pyre. Tables A. 10 and A. 11
document derivation of EFs for PAHs from the hay bales or straw added to an open pyre.
Appendix B presents estimates of dioxin emissions from open-pyre burning of 45,359 kg (50
tons) of carcasses using the quantities of fuels specified in Table 3.2.4. Although no data were
found to quantify dioxins produced from the combustion of animal carcasses alone (e.g., via
methane combustion), data were available linking dioxin releases to combustion of
wood/kindling and for crematoria in which a variety of unspecified materials also are combusted
with bodies. Table B.l in Appendix B documents the derivation of congener-specific EFs from
the wood added to an open pyre. For the coal added to an open pyre, dioxin emissions are not
expected, based on data from coal-fired power plants. Czuczwa and Hites (1984) reported that
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
fly ash from coal-fired power plants produce some CDDs, but that no TCDDs or
pentachorodibenzo-p-dioxin (PeCDDs) have been detected (ATSDR 1998). Moreover, CDDs
were present in much lower concentrations in fly ash from coal-fired plants than from fly ash
from municipal ash (ATSDR 1998). For the assessment, dioxin emissions from coal are set to
zero. For dioxin emissions from straw added to the pyre, dioxin emissions were reported in
2,3,7,8-TCDD toxicity equivalency factors (TEFs) (Appendix B, Section B.1.4).
Appendix D summarizes the air emission factors used for open-pyre burning by type of material
combusted. All emission factors originally in units of the quantity of chemical released to air per
quantity of material burned were converted to emission factors in units of quantity of chemical
released per unit time for air modeling.
1,5,2, Leaching front Remaining Open-Burning Ash
Following combustion of the pyre, the remaining ash on the ground might be removed to a
landfill. For this assessment, however, the ash is assumed to be buried or covered in place with a
layer of clean soil of sufficient depth to isolate the ash from plant roots. The area over which the
ash is distributed is the area of the pyre, which is 91.4 m long by 2.4 m wide (300 ft long by 8 ft
wide), or 223 m2 (= 0.056 ac or 400 ft2). Because the soil cover is permeable to rainwater,
contaminants in the ash have the potential to leach into subsurface soil and groundwater each
time it rains.
The amount of ash remaining from open burning was estimated from the quantities of carcasses
(i.e., 45,359 kg or 50 U.S. tons) and fuels placed in the pyre. The weight of ash remaining after
burning the carcass was assumed to be 6% of the uncombusted weight of carcasses (NRC 2000).
This assumption is the approximate midpoint of a distribution of body-ash content estimated by
the National Research Council (NRC 2000) for cattle with various body condition scores (based
on visual assessments of animal fatness).
Quantities of fuel materials for open burning, shown in Table 3.2.4, are based on USDA (2005)
recommendations for constructing a large animal carcass pyre. The ash remaining from woody
and other plant-based fuels, including timbers, kindling, and straw, is assumed to weigh 1% of
the original weight (Pitman 2006). Coal ash is assumed to weigh 2% of the uncombusted weight
(OSU 1999). Diesel, which is used as an accelerant, is not included in the ash contaminant data
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
because no ash remains from its combustion. The total ash quantity estimates by fuel type are
shown in Table 3.2.4 (above).
There were no available studies reporting contaminant concentrations in bottom ash (i.e., ash
remaining on the ground) from open burning of livestock carcasses. Consequently, the
assessment estimates chemicals in bottom ash by combining concentrations known to be in
carcasses and from each of the different fuel types (Table 3.2.6).
Table 3.2.6. Estimated Concentration of Chemicals Remaining in Bottom Ash from Open
Burning
Chemical
Concentration in
Ash from
Carcasses (jig/kg)
Concentration in
Ash from Wood
Fuels (jig/kg)
Concentration in
Ash from Coal Fuel
(Hg/kg)
Total
Concentration in
Pyre Ash (jig/kg)
Arsenic
na
3.0E+03
1.4E+02
3.9E+02
Cadmium
3.1E+02
1.2E+03
na
4.1E+02
Chromium
5.5E+03
1.9E+05
5.2E+04
3.0E+04
Copper
2.3E+04
1.5E+05
4.8E+04
4.0E+04
Iron
1.2E+04
1.2E+07
4.9E+07
2.9E+06
Lead
1.3E+03
7.7E+03
1.7E+04
2.6E+03
Manganese
2.3E+03
1.2E+07
2.8E+05
1.6E+06
Nickel
8.1E+03
2.7E+04
4.2E+04
1.2E+04
Mercury
na
3.2E+00
na
4.2E-01
Zinc
3.2E+03
4.9E+05
5.7E+04
6.8E+04
Total PAHs
7.3E+02
1.7E+04
4.3E+03
2.9E+03
Total Dioxin/furan
na
7.8E-02
na
1.2E-02
Abbreviations: na = not analyzed (in original citation); PAH = polycyclic aromatic hydrocarbon.
Concentrations in ash from the carcasses alone were estimated using data reported by Chen et al
(2003, 2004) for bottom ash from the HOWI livestock incinerator fueled by unrefined methane
(from which no ash residues are expected). As described above, the combustion characteristics
for the HOWI livestock incinerator are not necessarily representative of those for open-burning.
However, its relatively low burn temperature is comparable to ignition and combustion
temperatures of wood and coal reported by Bartok (2003).
Total PAHs were present in bottom ash at a concentration of 737 ng/g (Chen et al. 2003). The
concentrations of the individual PAHs evaluated for bottom ash were estimated from the
histograms presented by Chen et al. (2003) for the HOWI incinerator (top panel of Figure 4,
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
Incinerator A). Leaching from ash was modeled separately for individual PAHs based on those
data.
For metals in livestock carcass ash, the concentration of each metal in the buried ash are based
on EFs (in units of mg[metal]/kg[carcasses]) reported by Chen et al. (2004, Table 4) for bottom
ash in the HOWI incinerator (Incinerator A). Data were not available to estimate concentrations
of dioxins/furans in ash from burning of livestock carcasses.
Concentrations of all types of PAHs in the ashes of woody fuels from open burning were
estimated with data from Bundt et al. (2001); however, they did not identify concentrations of
individual PAHs in wood ash. Bundt et al. (2001) reported a total concentration for 20 PAHs of
16.8 mg/kg in ash collected from two medium-sized wood-chip furnaces operated at
temperatures between 550°C and 650°C. Because different PAHs exhibit different mobilities in
soils, that total concentration is apportioned to individual PAHs based on the PAH distribution
profile in bottom ash from the HOWI incinerated carcasses reported by Chen et al. (2003, Figure
4a).
The concentrations of metals in the ash residues of woody fuels used in open burning are based
on an analysis of bottom ash from wood burned at temperatures between 600°C and 1,000°C
(Narodoslawsky and Obennberger 1996). Concentrations of dioxins/furans in the ash of woody
fuels are from Wunderli et al. (2000, Figure 1), who reported concentrations of 17 individual
dioxin/furan congeners in bottom ash from wood combustion. Table 3.2.6 lists the estimated total
concentrations of total PAHs, individual metals, and total dioxin/furans in ash from the open-
burning option.
Chemicals in coal ash include PAHs and metals. Concentrations of metals and PAHs in coal
ashes are estimated using data from Tiwari et al. (2014) and Ruwei et al. (2013), respectively.
Concentrations of individual metals and total PAHs are shown in Table 3.2.6. Data were not
available to estimate concentrations of dioxins/furans in coal ash. Czuczwa and Hites (1984)
reported that TCDDs and PeCDDs (the homologue groups containing the most toxic congeners)
were not detected in ash from coal-fired power plants.
The total concentrations of chemicals in the bottom ash remaining from open burning (last
column in Table 3.2.6) are calculated from the mass-weighted contributions of each source of
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
ash (i.e., carcasses and fuel types). For each source of ash, the concentration presented in Table
3.2.6 was multiplied by the ash weight (see Table 3.2.4) to determine the mass of chemical from
the source in the total ash. For these calculations, "wood fuels" represent the total of ash from
timbers, kindling, and straw bales. The mass from the other three sources was then added for
each chemical, and the total was divided by the total weight of the ash to calculate the total
concentration of the chemical in the ash.
3,3. On-site Air-curtain Burning
The conceptual model for on-site air-curtain burning is presented in Figure 3.3.1. Note that the
compartments in this conceptual model are identical to those in the on-site open burning
conceptual model (Figure 3.2.1). The two management options differ with respect to air
emissions profiles and residual ash composition. With air-curtain burning, carcasses are burned
in a partially enclosed (partially open on top) refractory fire box. A forced air flow, driven by a
diesel-powered blower, creates an air "lid" over the burn area that recirculates much of the
smoke and soot within the fire box and provides additional mixing of air within the burning
mass. Hazardous chemicals can be released to the environment when combustion products
escape to air and when the ash is buried on-site under a layer of clean fill. Further assumptions
for the air-curtain burning management option are stated in Table 3.3.1.
The characteristics of air emissions and ash remaining after air-curtain burning depend on
several factors, including combustion temperature, effectiveness of the "air curtain" in retaining
ash particles, carcass type, and the nature and amounts of fuels used. Although Engstrom (2015)
reported coal-fired air-curtain burning during the 2015 outbreak of highly pathogenic avian
influenza (HPAI) in the United States, published sources (e.g., NABCC 2004; SKM 2005)
generally describe air-curtain burning as being fueled primarily with scrap wood, with smaller
amounts of diesel, or other liquid fuels used as accelerants to initiate combustion.
The National Agricultural Biosecurity Center Consortium (NABCC) (2004) reported that the
wood-to-carcass ratios for air-curtain burning vary between 1:1 and 2:1. As reported by SKM
(2005) the average wood-to-carcass ratio for four in-ground carcass air-curtain burning trials in
in New Zealand was 2.29. Ratios for the individual trials ranged from 1.84 to 3.01. At the expert
workshop discussed in Section 2.5, attendees familiar with air-curtain burning equipment used
during previous HPAI outbreaks observed that a wood-to-carcass ratio as high as 4:1 could be
46
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
needed. For the 2002 HPAI outbreak in Virginia, Peer et al. (2006) reported that approximately
4.4 U.S. tons of wood were needed per U.S. ton of poultry carcasses burned. Reasons for needing
more wood than "expected" include heavy rains on the initially stockpiled wood and use of low-
quality wood (e.g., rotted, saturated, or scrap wood including pieces of metal) by contractors
after the initial wood stockpile was burned. As a conservative approach, the 4:1 wood to carcass
ratio is assumed for the air-curtain burning option.
The rate at which carcasses and fuels burn depends on the nature of those materials and the
design and operation of the burner. Ford (2003), as cited in NABCC (2004)a communicated a
rate of 6 tons (5,443 kg) per hour, presumably for carcasses and fuel combined. Earlier, Ford
(1994) reported 91,060 lb (41,300 kg) of hog carcasses burned during three 7-hr periods in an
air-curtain burner, which equals approximately 2.2 U.S. tons (2,000 kg) of carcasses per hour.
The quantity of wood burned over the same time period (21 hr) equaled 33 cords (120 m3).
Assuming a wood density of approximately 500 kg/m3 (e.g., for pinewood), the weight of 33
cords would be approximately 60,000 kg, for a wood-to-carcass ratio of approximately 1.5:1 and
a total throughput of 5.5 tons (5,000 kg) of carcasses plus wood per hour. Another source,
McClaskey (2014, p 180), reported combustion of animal carcasses at a rate of 2 tons (1,814 kg)
per hour (the quantity of wood required was not specified). Investigators who conducted an air-
curtain burning trial in New Zealand reported a lower rate of carcass and fuel burning (SKM
2005). They reported average throughputs of 0.65 tonnes (650 kg) of carcasses per hour and 1.8
tonnes (1,800 kg) wood per hour for a total of 2.45 tonnes (2,450 kg) or 2.7 U.S. tons of fuel plus
carcasses. Specifications available for a commercially available air-curtain burner similar to the
design assumed for this analysis indicate higher possible throughputs (e.g., 6-10 U.S. tons
[5,443-9,072 kg] per hour; Air Burners, Inc. 2012); however, specifications note that the actual
burn rate will depend on many factors, including materials burned. Air-curtain burners are often
used to dispose of woody debris only, which is likely to burn faster than carcasses.
Participants in the expert workshop discussed in Section 2.5 recommended a burn duration of 48
hr for the exposure assessment scenario. With 50 U.S. tons (45.4 tonnes) of carcasses and 200
U.S. tons (181 tonnes) of wood fuel (i.e., four times the weight of the carcasses), the throughput
over 48-hr burn would equal 5.2 U.S. tons (4,720 kg or 4.7 tonnes) per hour (i.e., 50 U.S. tons of
carcasses + 200 U.S. tons of fuel) / 48 hr = 5.2 U.S. tons/hr.)
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
On-site Transportation
Combustion
Burial of ash
in place
Wet & Dry Particle
Deposition;
Diffusive Vapor
Exchange
Wet & Dry
Deposition
Particle
Deposition,
Stomatal Uptake
Erosion
£ Runoff
Terrestrial
Plants
Root uptake
Uptake,
bioaccumulation
Aquatic
Life
Leaching
Sedimentation,
Resuspension, &
Diffusive Exchange
Surface Water
Recharge
Inhalation
Uptake,
bioaccumulation
Incidental
Ingestion
Ingestion
Livestock
Ingestion
Ingestion &
Inhalation
Ingestion
Ingestion
Humans
Inhalation
Air
Soil
On-site Lake
Sediment
Well
Water
Groundwater
Natural Disaster
Mortalities
Air Curtain Burning
Figure 3.3.1. Conceptual model for exposure pathways from on-site air-curtain burning of
livestock carcasses.
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
Table 3.3.1. Assumptions for On-site Air-curtain Burning of Livestock Carcasses
Conceptual
Model Feature
Assumptions
Burner Design
and Use
¦ Carcasses are burned in an above-ground refractory box with a forced-air "curtain" on top.
The fire box measures 8.3 m long, by 2.6 m wide, and 2.5 m height, and the overall
dimensions of the air-curtain burner unit are 11.4 mlong, by 3.6 mlong, and 2.9 m high.6
¦ Combustion fuels include scrap wood, previously stockpiled logs, and diesel fuel. Wood
fuel is supplied at a 4:1 ratio by weight to carcasses (see text).
¦ The combustion temperature in the carcass mass is 850°C (1,600°F).
¦ The air-curtain burner is operated continuously for 48 hr to burn 226,796 kg (250 U.S.
tons) of carcasses and associated fuels. (For safe continuous operation, three worker shifts
work 8 hr each.)
¦ Combustion ash is placed in an excavated 21.6 nfpit with a length and width equal to the
dimensions of the fire box (8.3 m long by 2.6 m wide).
¦ The burial trench for the ash is unlined and covered with clean fill.
Air Pathways
¦ Human inhalation of particulate matter and vapor-phase gases is assumed to occur only
near the air-curtain burner, and be at the maximum concentration emitted from the unit.
¦ Reference air concentrations to protect individual humans should also be protective of
mammalian livestock. Therefore, inhalation by nearby livestock over a two-day exposure is
not assessed (USEPA 2005a).
¦ Downwind air concentrations of gas-phase chemicals could be absorbed by plant leaves.
The short combustion duration (48 hr) relative to the time required by crop plants to mature
to harvest suggests that foliar absorption from the air and incorporation into plant tissues
would be negligible.
Soil Pathways
¦ Incidental soil ingestion by humans and livestock is considered for agents deposited from
air to soil. Deposition from air occurs over a short period of approximately two days.
¦ Fanning, livestock pasturing, and grazing do not occur on the ash disposal site. If the cover
fill is disturbed by these activities, plants might suffer root bum while animals might be
exposed to specific metals from negligible to toxic concentrations. This is not further
considered in the assessment because of the high levels of uncertainty associated with this
type of exposure.
¦ Buried ash does not contribute to surface soil concentrations.
Groundwater and
Well Water
¦ Leaching to groundwater is assumed only for the ash burial trench; leaching following air
deposition to the agricultural field is assumed to not contribute significantly to groundwater
concentrations.
¦ The water table will be assumed to be 1 m below the bottom of the ash pit.
¦ An on-site groundwater well is used for drinking water. Well water serves farm residents.
Livestock drinking well water is assessed only if concentrations estimated for low-flow
aquifers sufficient to supply one household indicate possible concern (see Section 3.1.2).
¦ Groundwater is not treated or filtered before use.
Surface Water,
Sediment, and
Aquatic Life
¦ Incidental ingestion from recreational surface water use is not included in the conceptual
model.
¦ Ingestion of aquatic life includes recreationally caught fish.
Production of
Food on the
Farm
¦ The production of food on the farm includes terrestrial plants consumed by humans and
livestock, with possible transfers to dairy products and eggs.
6 Assumptions about the refractory box design are based on the specifications of Air Burners Inc., Model S-372, available at:
http://www.airbumers.com/DATA-FILES Print/ab-s327 Specs PRNT.pdf.
49
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
Abbreviations: hr = hour.
Section 3.3.1 discusses chemicals released to air from air-curtain burning, and Section 3.3.2
discusses possible releases from buried ash to groundwater from percolation of rainwater through
the ash layer.
1,5,1, Releases of Combustion Products to Air
The same inorganic and organic chemicals are released to air from air-curtain burning as from
open-pyre burning, but at different rates because of the different fuels used, improved
effectiveness of combustion, and different burn temperatures. Emission factors forPAHs and
metals from air-curtain burning were derived from stack flue measurements published by Chen
et al. (2003, 2004) for a livestock disease control incinerator (identified as LIWI by the authors).
The burn temperatures (i.e., 755-891°C) reported by Chen et al. (2003, 2004) for the LIWI
incinerator are comparable to temperatures typically achieved during air-curtain burning of
livestock carcasses. Ford (2003) and McPherson Systems, Inc. (2003), both cited by NABCC
(2004), reported air-curtain burning temperatures as high as 1,600°F (~871°C). The United
Kingdom Department for Environment, Food, and Rural Affairs (DEFRA 2002, cited in NABCC
2004) reported burn temperatures in the range of 600-1,000°C. Those temperatures are
comparable to the temperatures reported by Chen et al. (2003, 2004) for the LIWI incinerator.
However, other investigators have reported substantially higher air-curtain burning temperatures.
Ford (1994) reported 1,800-2,800°F (980-1,540°C) for an evaluation of air-curtain burning of
hog carcasses (high fat content), and the technology overview currently provided by McPherson
Systems, Inc. (2015) reports burning temperatures from 1,800-2,500°F (980-1,370°C) In New
Zealand, temperatures measured above the flames in a trench with an air-curtain burner along the
long side ranged from 270 to 855°C in the same trench measured at roughly the same time,
depending on the sampling location in the trench (SKM 2005). Higher temperatures were
reached, but could not be measured because radiant heat prevented the workmen from
approaching sufficiently close to suspend the thermistor over the trench. As listed in Table 3.3.1,
this assessment assumes 850°C in the mass of carcasses for air-curtain burning. This means the
LIWI incinerator data for PAH and metal emissions from Chen et al. (2003, 2004) are considered
representative for releases from carcasses for that burn temperature.
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
Table 3.3.2 lists the air EFs reported by Chen et al. (2003) for PAHs from the LIWI in three
molecular weight categories. Appendix A presents congener-specific EFs for PAHs released to
air. Table A.4 in Appendix A documents the derivation of congener-specific PAH EFs from
carcasses in the air-curtain burner, while Table A. 7 documents the derivation of congener-
specific PAH emissions from wood added to the air-curtain burner.
Table 3.3.2. Emission Factors for PAHs from LIWI Incinerator Carcass Burning (mg/kg
waste)3
Waste Stream
Total PAHs
LM PAHs
MM PAHs
HM PAHs
Stack Flue Gas
2.867
2.435
0.234
0.198
Abbreviations: PAHs = polycyclic aromatic hydrocarbons; LIWI = livestock disease control incinerator; LM = low molecular
weight; MM = medium molecular weight; HM = high molecular weight.
a Based on Chen et al. (2003), Table 5, LIWI. Total PAHs are based on the sum of 21 PAH species. Low, medium, and high
molecular weight groups include species containing two- and three-ringed PAHs (LW), four-ringed PAHs (MM), and five-, six-,
and seven-ringed PAHs.
The derivation of EFs for dioxins from air-curtain burning using woody fuels is described in
Appendix B, Section B.1.2. Chen et al. (2003, 2004) did not sample for dioxins. For dioxins
released from burning 200 tons of wood, data from industrial wood-burning facilities (i.e.,
USEPA 2012) represent the higher burn temperatures for air-curtain burning than for open-pyre
burning (Table B.2).
Emission factors for metals released from air-curtain burning are based on the sum of metals
released into the air from carcass burning (Table 3.3.3) and metals released from the wood added
to the air-curtain burner. Though coal can be used to supplement or replace wood fuel to burn
carcasses in an air curtain burner, it seems not to be a common practice. Review of the carcass
management literature found no reports of coal addition to air-curtain burners used in carcass
incineration. There are several sources that discuss wood alone as a fuel source.
Table 3.3.3. Emission Factors for Metals from LIWI Animal Carcass Incineration (mg/kg
waste)
Waste Streama
Fe
Cd
Cr
Cu
Mn
Ni
Pb
Zn
Stack Flue Gas (vapor-phase)
1.10
0.01
0.07
0.02
0.02
0.06
0.18
0.19
Bottom Ash (particle-phase)
412
0.03
3.74
11.9
8.61
7.22
35.7
89.2
a Based on Chen et al. (2004), Table 4, LIWI.
Appendix D summarizes the air emission factors used for air-curtain burning by type of material
combusted (i.e., carcasses and wood). All emission factors originally in units of the quantity of
51
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
chemical released to air per quantity of material burned were converted to emission factors in
units of quantity of chemical released per unit time (i.e., g/s) for air modeling assuming 226,796
kg (250 U.S. tons) of carcasses and wood fuel over 48 hr.
1.5.2. Leaching from Combustion Ash
Table 3.3.4 provides the assumptions used to estimate the amount of ash remaining from the air-
curtain burning option. The quantity of ash from burning carcasses (i.e., 2,722 kg or 6% of the
original carcass mass) is the same estimate used for the open burning option, which was
described in Section 3.3.4. Although less ash is expected from air-curtain burning of the
carcasses than from open burning because of the higher combustion temperature, there were no
data identified that would allow preparation of separate estimates for the ash generated from
carcasses under the two combustion options.
Table 3.3.4. Quantity of Ash from Air-curtain Burning
Material
Assumptions
Fuel Mass (kg)
Ash Percent
(%)
Ash Mass (kg)
Carcasses
100 carcasses, 1,000 lb (453.6 kg) each
45,359
6
2,722
Wood
4,000 lb per carcass a>b
181,437
0.3
498
Total
3,220
Abbreviations: lb = pound.
aNABCC (2004).
b Hie assumed amount of wood represents a 4:1 fuel-to-carcass ratio, see text.
For wood fuels, however, a higher combustion efficiency is assumed for air-curtain burning
(0.3% remaining ash) than for open burning (1%). This assumption for air-curtain burning is
based on Narodoslawsky and Obennberger (1996), who reported a wood dry weight of 88% (i.e.,
12% moisture), a percent ash (dry weight basis) of 0.4%, and 78% bottom ash (as opposed to fly
ash). Multiplying those percentages results in the final bottom ash estimate of 0.3% of the
original weight of the fresh wood, or 498 kg of wood ash remaining (Table 3.3.4).
Table 3.3.5 presents the estimated concentrations of chemicals remaining in bottom ash from the
air-curtain burning option. The estimated concentrations of metals and PAHs from carcass
combustion are based on bottom ash data reported by Chen et al. (2003, 2004) for the LIWI
incinerator, which as described above, achieved combustion temperatures comparable to air-
curtain burning.
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
Concentrations of metals, PAHs, and dioxins/furans in the bottom ash remaining from the wood
fuels used in air-curtain burning are based on the same data sources used for the woody fuels of
open burning (see Section 3.1). The available data could not differentiate the concentrations of
metals and dioxin/furans in the wood ash from the two options. Therefore, the assessment uses
the same concentrations for those chemicals in wood ash as in Tables 3.2.6 and 3.3.5.
Table 3.3.5. Estimated Concentration of Chemicals in Ash from Air-curtain Burning
Chemical
Concentration in Ash
from Carcasses (jig/kg)
Concentration in Ash
from Wood Fuels (jig/kg)
Total Concentration in Air
curtain Burning Ash (jig/kg)
Arsenic
na
3.0E+03
4.6E+02
Cadmium
3.0E+01
1.2E+03
2.1E+02
Chromium
3.7E+03
1.9E+05
3.2E+04
Copper
1.2E+04
1.5E+05
3.3E+04
Iron
4.1E+05
1.2E+07
2.2E+06
Lead
3.6E+04
7.7E+03
3.1E+04
Manganese
8.6E+03
1.2E+07
1.9E+06
Nickel
7.2E+03
2.7E+04
1.0E+04
Mercury
na
3.2E+00
5.0E-01
Zinc
8.9E+04
4.9E+05
1.5E+05
Total PAHs
4.7E+02
1.1E+04
2.1+03
Total Dioxin/furan
na
7.8E-02
1.2E-02
Abbreviations: na = not analyzed (in original citation); PAHs = polycyclic aromatic hydrocarbons.
The PAH concentrations in wood ash from air-curtain burning were estimated separately from
PAH concentrations in wood ash remaining after an open pyre. Bundt et al. (2001) reported a
total PAH concentration of 16.8 (J,g/kg in wood ash produced by medium-sized wood-chip
furnaces burning at 550-650°C, which are temperatures consistent with the assumed open
burning temperature (i.e., 550°C) scenario, and less than the temperature assumed for air-curtain
burning (i.e., 850°C). While the total PAH concentration of 16.8 (J,g/kg could be used as the total
PAH concentration in wood ash from pyre burning, it does not necessarily appear appropriate for
air-curtain burning.
PAH concentrations were not identified for wood burning at temperatures consistent with the air-
curtain burning option, but they are expected to be lower than in bottom ash from an open pyre
due to the higher air-curtain burn temperatures. PAH concentrations for wood burning were
estimated using data available from Chen et al. (2003) on PAHs in ash from high- and low-
53
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
temperature carcass burning. Specifically, Chen et al. (2003) reported total PAH concentrations
in bottom ash from carcass burning with the HOWI (low temperature, comparable to open
burning) and LIWI (higher temperature, comparable to air-curtain burning) incinerators. The
ratio of total PAHs in as from the LIWI to HOWI incinerators is 0.65:1 (i.e., 474 [j.g/kg:732
(j,g/kg). That ratio, applied to the total wood ash PAH concentration of 16.8 (J,g/kg reported by
Bundt et al. (2001), suggests the total PAH concentration in bottom ash from wood burning in an
air-curtain burner could be 10.9 (J,g/kg. The relative abundance of individual PAH compounds
reported by Chen et al. (2003, Figure 4b in original report) for the LIWI incinerator was used to
apportion the total estimated PAH concentration to the individual compounds.
The last column in Table 3.3.5 shows the total concentrations of chemicals in the ash remaining
from air-curtain burning. The concentrations of each chemical in carcass ash and in wood ash is
based on the relative weight of ash from those materials, which are shown in Table 3.3.4. In
other words, the concentration of each chemical in wood ash was multiplied by 4 (weighted by a
factor of 4) to reflect the 4:1 ratio of wood:carcasses to estimate the concentration in total ash.
3,4. On-site Burial
Figure 3.4.1 provides an overview of the conceptual model for the on-site livestock carcass
burial option. In this option, livestock carcasses are placed in an unlined, excavated pit or trench
in a suitable location on site.7 The carcasses are covered with clean fill creating a mound over the
site that will flatten over time as the carcasses lose fluids and other mass during decomposition.
Although access to the site is not restricted, it will not be used in the relatively near future for
crop farming or raising livestock; it will be seeded over for soil stabilization.
As the carcasses decompose rapidly at first (over months) with the remainder decomposing more
slowly (over years), vapor-phase chemicals can diffuse upward though the soil cover to
aboveground air. Soluble chemicals can leach with carcass fluids and with rainwater permeating
through subsurface soils to groundwater. In addition, colloids and small particulates (e.g., on
order of microns) with sorbed chemicals and microbes can percolate through any larger
interstitial spaces or pores (e.g., along plant roots) through subsurface soils. Where they contact
7 Mass livestock burial trenches might be created off-site following some natural disasters. It is assumed that in those cases, state
and federal representatives would participate in selection of location(s) with appropriate conditions (e.g., high over
groundwater, far from any groundwater wells).
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
the solid-phase pore walls, adsorption (and to a lesser extent desorption) is likely to occur (Ginn
et al. 2002; Kim and Kim 2012; Li et al. 1996). Some fraction of the particles might reach
groundwater, with the remainder effectively fixed to stationary soil particles (i.e., filtered out).
Equilibrium desorption might continue for years, but would yield negligible concentrations in
groundwater. Many of the microbes described in Section 2.4.2 are considered facultative
anaerobes and can survive in environments with or without the presence of oxygen. However,
Coxiella burnetii is considered to be aerobic and can only survive in the presence of oxygen; it
would be inactivated if it reached the saturated zone.
Diffusion through cover soil
On-site Burial
Air
Leaching from ro
subsurface soii and
Groundwater
Stomatol Uptake
Terrestrial
Plants
Leaching
Surface Water
Recharge
Uptake,
bioaccumufotion
Inhalation
ingestion
Livestock
Sedimentation,
Resuspension, &
Diffusive Exchange
Sediment
1 '
J Uptake,
Aquatic
Life
Ingestion
biooccumulation
Inhalation
Ingestion &
Inhalation
Well
Water
Ingestion
Humans
Ingestion
Figure 3.4.1. Conceptual model for exposure pathways from on-site burial of livestock
carcasses.
Gases formed during decomposition initi ally cause carcasses to bloat. If the carcass abdominal
cavities are not opened before burial, if the top of the burial trench is not adequately covered
with dirt, or if there is insufficient venting of the carcass pit to air, bloated carcasses or fluids
might emerge from the surface (USDA 2005). This assessment, however, assumes the carcasses
are properly prepared, placed, and covered within the pit so there is slow release of vapor-phase
55
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
gases to air over the months required for biodegradation. When gases reach the surface, they are
readily diluted in ambient air. For this reason, the inhalation pathways pictured in Figure 3.4.1 do
not affect the assessment Leaching of chemicals and microbes toward groundwater is the focus
of the exposure pathway assessment for burial as discussed in Section 3.4.1. Table 3.4.1
identifies further assumptions for the on-site burial conceptual model and exposure scenario.
Table 3.4.1. Assumptions for the On-site Burial of Livestock Carcasses
Conceptual Model
Feature
Assumptions
Burial Trench
Design and Use
¦ 45,359 kg (50 U.S. tons) of livestock carcasses are placed in a single trench that is 9 ft
deep, 7 ft wide, and 300 ft long (2.7 by 2.1 by 91.4 m) based on guidelines provided by
USDA (2005).
¦ The carcasses are covered with 6 ft (1.8 m) of soil, including 3 ft (0.9 m) mounded over
the site starting at ground level (USDA 2005).
¦ An unsaturated zone of 1 m (3.3 ft) extends below the bottom of the burial trench.
Air Pathways
¦ Gases generated by carcass decomposition can slowly seep upward through cover soil
to air.
¦ Microbes and non-volatile chemicals are not released to air.
Soil Pathways
¦ Volatile gases emitted to air from on-site burial will remain in air and not be deposited
to the surface soil (i.e., sporadic wet deposition would be effectively cancelled by
vaporization).
¦ Soil erosion and runoff from the burial site to surface water are not included in the
conceptual model, because there is soil capping the burial site.
¦ Methane from the anaerobic phase of carcass decomposition can permeate through
subsurface soils. While accumulation of methane in a closed building could pose an
explosion risk, this assessment assumes there will be no accumulation of methane after
release.
Groundwater and
Well Water
¦ Chemicals and pathogens can leach to groundwater from carcasses and subsurface soil
beneath the burial trench.
¦ The water table remains at least 1 m below the burial trench throughout the year.
¦ An on-site groundwater well is used for drinking water, other household water uses
(e.g., showering) (see Table 3.2.1).
¦ Groundwater is not treated before use.
¦ Humans can inhale aerosolized/volatilized agents from well water during showering
and other home water uses.
Surface Water,
Sediment, and
Aquatic Life
¦ Chemicals and microbes from buried carcasses can reach the on-site lake only via
groundwater (assuming appropriate hydrology).
¦ Humans on the farm ingest fish caught from the on-site lake.
Production of Food
on the Farm
¦ Potential exposures via food produced on the farm are not assessed for this option (see
Table 3.4.2).
Abbreviations: ft = feet; USDA = U.S. Department of Agriculture.
Not shown in Figure 3.4.1, is methane gas produced by anaerobic decomposition of the livestock
carcasses that might travel horizontally through soils in the unsaturated zone soils, potentially
posing an explosive threat if it accumulates inside a closed structure. The process would be
56
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
similar to landfill gas intrusion, which has occurred when methane produced within a landfill
migrates horizontally through the ground, seeps into a building foundation, and accumulates in
the enclosed airspace to an explosive concentration (USEPA 2005a). Leaching from buried
carcasses to groundwater is discussed in Section 3.4.1, and seepage of methane gas from a burial
trench is discussed in Section 3.4.2.
1,5,1, Leaching front Burled Carcasses
Table 3.4.2 summarizes the basis of assumptions for estimating releases from carcass burial.
Unlike combustion of carcasses, which is completed over a few days, decomposition of buried
carcasses and leaching of materials from carcasses occurs over much longer time frames. Young
et al. (2001) estimated likely annual chemical releases from buried carcasses over a 60-year
period (Table 3.4.3). They estimated that 60% of a buried mammalian corpse is readily degraded
(half-life of 1 year), 15% degrades at a moderate rate (half-life of 5 years), 20% degrades slowly
(half-life 10 years), while 5% is inert (the amount left over after high-temperature incineration,
primarily mineral salts). The release of bodily fluids for buried livestock carcasses is rapid at
first, with steadily declining release rates after the first few months or year (Young et al., 2001).
Young and colleagues estimated that approximately 33% of the carcass mass is released as fluids
during the first 2 months after burial, of which half is released within the first week. If the
leachate has the density of water (i.e., 1 kg/L), for 45,359 kg (50 U.S. tons) of carcasses,
approximately 15,000 L of fluid would be released in the first 2 months, with 7,500 L released
during the first week. Approximately 60% of the carcass mass is released as fluid by the end of
the first year (Young et al., 2001), meaning that approximately 27,000 L can be expected to be
released from the carcasses in the first year.
During the first few months of fluid release from the carcasses, water entering the pit from
precipitation will dilute the liquid. When the fluid release declines after the first few months of
degradation, however, leachate concentrations can depend on local precipitation as well as
conditions in the burial trench. The contribution of precipitation was not included in the leachate
modeling approach for the on-site burial option because depending on when precipitation
occurred, it might or might not dilute concentrations during the most active period of leachate
releases.
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
Table 3.4.2. On-site Burial Release Characterization
Release Type
Approach, Assumptions, and Information Sources
Leaching to
subsurface soils
and to
groundwater
¦ Total leachate from 45,359 kg of carcasses is likely to be 15,000 L over the first 2 months
following burial.
¦ Chemical releases are estimated in three time steps: first 1-2 weeks, first 8-10 weeks, and
the first year. Releases after the first year would decrease over time.
¦ Young et al. (2001) estimated release rates for total organic carbon (TOC), ammonium
(NH4+), potassium (K+), and chloride ions (CI ) for the time steps (Table 5.3 in Young et al.
2001). Field measurements of chemical concentrations in leachate at specific times after
burial (e.g., Pratt and Fonstad 2009; Yuan et al. 2013) extend the chemicals covered from
those estimated by Young et al. (2001; i.e., TOC, NH4+, CI", and K+) to include the
remaining chemical constituents of the carcasses (Section 2.4.1 above).
Diffusion of
gases through
cover soil
¦ Concentrations of hydrogen sulfide (ITS) and ammonia (NH3) reported by Glanville et al.
(2006) indicate that odor thresholds might, on occasion, be exceeded close to a burial
trench. In general, however, the passive rate of release, distributed over the length and width
of the burial trench, and high dilution by the atmospheric air under most meteorological
conditions preclude the releases from reaching concentrations that might be hazardous to
humans and other animals.
Table 3.4.3. Potential Annual Releases (kg) of Chemicals from 1,000 kg Buried Livestock3
Year
TOC
nh4
CI
K
1
24
2.9
0.12
0.28
2
10.1
1.2
0.05
0.12
3
4.8
0.6
0.03
0.07
4
2.7
0.3
0.015
0.035
5
1.8
0.2
0.008
0.018
6
1.3
0.2
0.006
0.014
7
1.1
0.1
0.006
0.014
8
1.0
0.1
0.004
0.009
9
0.8
0.1
0.004
0.009
10
0.8
0.08
0.004
0.009
20 (average/yr)
0.3
0.05
<0.002
<0.005
30 (average/yr)
0.1
0.02
<0.002
<0.005
40 (average/yr)
0.03
<0.008
<0.002
<0.005
50 (average/yr)
0.02
<0.008
<0.002
<0.005
60 (average/yr)
0.003
<0.008
<0.002
<0.005
Abbreviations: TOC = total organic carbon; yr = year.
a From Table 5.3 of Young et al. (2001).
Estimates of the chemical concentrations in leachate percolating from an unlined burial trench
over time are based on measured concentrations in leachate accumulating in experimental
livestock carcass burial pits in Saskatoon, Canada, as reported by Pratt and Fonstad (2009). Each
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
of five pits was 7 by 9 m2 and 2.5 m deep. All five pits were completely lined with impermeable
40-mil polyethylene with a leachate sampling tube at the bottom center of each. Three pits, one
each for cattle, swine, and poultry, were covered with a 40 mil liner and capped with 0.9 to 2 m
of soil. Two ventilation pipes placed through the top liner allowed for the escape of gases formed
during carcass decomposition.
Pratt and Fonstad (2009) sampled the leachate accumulating above the bottom liner of the pit at
periodic intervals after burial over a 2-year period. The concentration profiles of different
chemicals in the accumulated leachate over a two-year period were similar across livestock
categories, as shown in Table 3.4.4.
Table 3.4.4. Average Two-year Leachate Concentrations (mg[chemical]/L[leachate]) by
Livestock Category (Pratt and Fonstad 2009)
Chemical Species
Poultry
Swine
Cattle
Bicarbonate
39,133
48,467
50,733
Chloride
2,570
2,380
2,813
Nitrogen (ammonium)
10,400
13,300
14,100
Nitrogen (nitrate and nitrite)
2.3
3.1
3.8
Calcium
81
48
36
Magnesium
79
17
18
Phosphorus
1,927
1,513
1,150
Potassium
2,400
2,400
2,000
Sulfate
3,970
3,900
2,900
Zinc
2.2
1.8
1.7
The concentration of elements in leachate from cattle burial pits as reported by Pratt and Fonstad
(2009) are used to assess possible human exposures via groundwater. Those data are presented in
Table 3.4.5.
For this exposure assessment, a groundwater well is assumed to be located 30.5 m (100 ft)
downgradient of an unlined burial trench containing 45,359 kg of cattle carcasses. Data used to
represent the three time-frames of interest—first week, first 8-10 weeks, and first year—are
included as the first three data columns in Table 3.4.5.
As described by Pratt and Fonstad (2009), many of the chemical species concentrations (e.g.,
aluminum, calcium, magnesium, manganese, molybdenum, nickel) were highest during the first
weeks of burial, and were lower in samples taken after a few months and years (in Table 3.4.5,
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
see chemicals with the time of maximum concentration occurring at 0.5 months). Those
chemical species might have complexed with other chemicals and precipitated out of solution or
become strongly sorbed to organic particulate matter. Sulfate concentrations might have declined
(Pratt and Fonstad 2009) as hydrogen sulfide escaped to air via the two vent pipes. The
concentrations of other chemicals, notably organic and inorganic carbon, boron, chloride, and
ammonium nitrogen increased over time in the contained leachate as carcass degradation
continued after the major releases of fluids in the first two months (Table 3.4.5, chemicals with
time of maximum concentration at 12 months).
1.5.2. Methane Seepage from Burled Carcasses
Landfill gas intrusion into structures is a well-understood phenomenon that caused at least 30
incidents of property damage or of death or injury to residents or workers in nearby buildings
(USEPA 2005a). There are no methane explosion damage cases associated with livestock carcass
burials. However, a 45,359 kg carcass burial would produce significant quantities of methane,
which makes the risk of damage worthy of discussion.
Yuan et al. (2013) studied gas production over 650 days from cattle carcasses "buried" in
laboratory-scale anaerobic decomposition reactors loaded with measured amounts of cattle
carcass material. They found the average rate of methane production to be 0.58 L/kg-d (dry
weight basis) for homogenized carcass materials. Non-homogenized carcass materials produced
methane at one fifth of that rate (i.e., approximately 0.12 L/kg-d dry weight) and the equipment
clogged; those results therefore are not considered further. Gas production was approximately
65% methane and 20% carbon dioxide. Other gases produced included oxygen (O2) and nitrogen
(N2) at approximately 5% and 15%, respectively. Methane production did not start until the
carcass materials reached a favorable pH around day 50 of the experiment, and it varied
substantially from day to day after that, with its production ceasing between 340 and 650 days
depending on the reactor vessel.
The total yield of methane from homogenized carcass materials was 0.33 m3/kg. Extrapolating
the bench-scale results to cattle carcasses of 500 kg (1,100 lb) each, Yuan et al. (2013) estimated
that 50 m3 (36 kg) of methane would be produced per carcass. That means production of 4,540
m3 (3,266 kg) methane per 45,359 kg of carcasses over the decomposition interval.
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
Table 3.4.5. Estimated Concentration of Elements in Accumulating Leachate from Cattle
(pit no. 4)
Chemical
Cone. 1 Week
After Burial
Average
Concentration
Over 1st 3
Sampling
Events (mg/L)
Average
Concentration
Maximum
Concentration
(mg/L)
Time of
Maximum
Species
(mg/L)
(08/17/05)
0 12 Months
(mg/L)
(months after
burial)
Aluminum
1.7
1.45
0.62
1.70
0.5
Ammonium3
5,200
7,703
10,975
13,900
3
Barium
0.3
0.47
0.18
0.60
1
Beryllium
nd
nd
nd
nd
na
Bicarbonate
35,100
39,633
47,245
53,400
9
Boron
nd
0.80
0.67
0.96
12
Cadmium
nd
nd
nd
nd
na
Calcium
60
37
38
60
0.5
Chloride
2,605
2,590
2,482
3,266
12
Chromium
nd
nd
nd
nd
na
Cobalt
0.1
nd
nd
0.10
0.5
Copper
0.6
1
0.78
1.10
1
Inorganic Carbon
6,900
7,797
9,250
10,400
9
Organic Carbon
43,000
45,000
55,810
64,800
12
Iron
110
66
32.6
110.0
0.5
Lead
nd
nd
nd
nd
na
Magnesium
30
23
18.8
30.00
0.5
Manganese
0.5
0.4
0.27
0.50
0.5
Molybdenum
1.8
0.7
0.18
1.80
0.5
Nickel
0.4
0.25
0.07
0.40
0.5
Nitrate3
23
13
5.9
23.0
0.5
Nitrite3
Total Nitrogen
18,300
15,100
18,300
20,100
9
Phosphorus
920
1,173
1,174
1300
1
Potassium
1,900
2,033
2,068
2,200
9
Silicon13
29
27
24
29.00
0.5
Silver
nd
nd
nd
nd
na
Sodium
1,600
2,100
2,016
2,700
2
Strontium
0.7
0.43
0.29
0.70
0.5
Sulfate
3,700
4,833
5,026
6,800
3
Sulphur
1,200
1,600
1,670
2,300
3
Titanium
0.2
nd
0.01
0.20
0.5
Vanadium
nd
nd
nd
nd
na
Zinc
3.5
4
2.6
4.20
1
Zirconium
0.2
nd
0.01
0.20
0.5
Source: Pratt and Fonstad (2009).
Abbreviations: nd = not detected; na = not applicable.
a As nitrogen (N).
b Soluble silicon.
For methane intrusion from a burial trench initially containing 45,359 kg of cattle carcasses into
a closed building, a number of conditions must be met. First, methane generation and release into
adjacent soils depends on the type and age of the waste, its moisture content, the type of cover
material, ambient temperature, and other factors. For example, permeable cover materials, such
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
as gravel and sand, allow for the gas to ascend vertically more rapidly than silts and clays
(ATSDR 2001), thereby reducing the horizontal transport of methane gas.
Second, the subsequent movement toward structures depends on the position of the structures
relative to the source, the distance from the source, as well as conducive geological and soil
conditions. The direction, flow rate, and travel distance of gas migration is controlled by a
number of environmental variables and is primarily driven by a variation in concentration
(diffusion) and/or pressure differences (convection) (NHBC-RSK 2007). Heavy rains post-burial
can seep into void spaces occupied by gas, pushing the gas to lower pressure areas. Methane gas
will also migrate via the path of least of resistance, meaning that natural rock fissures and man-
made pipes provide easy paths for the gas to travel to potentially dangerous areas. Foundation
cracks in buildings near a burial site provide a path for methane to migrate through and
accumulate in the building, significantly increasing the risk of explosion (ATSDR 2001).
Finally, the concentration of methane seeping into a building must be within a relatively narrow
explosive range. A highly flammable gas, methane becomes explosive in mixtures with oxygen
between a lower explosive limit (LEL) of 5% volume of methane/volume of air (v/v) and an
upper explosive limit (UEL) of 15% v/v. Methane concentrations above the UEL (> 15%/v) are
too rich (O2 levels are too low) to support combustion (USEPA 2005a).
In the 1990s, USEPA regulations under both Resource Conservation and Recovery Act (RCRA)
and the Clean Air Act (CAA) reduced the likelihood of landfill gas intrusion by requiring landfill
gas collection and management. Those regulations, however, do not apply to livestock carcass
burial.
There are no technical or regulatory barriers to prevent methane explosion damage from
occurring at or near a livestock carcass burial location. Inserting vertical narrow (e.g., half-inch)
pipes into the buried carcass mass in several locations, however, could assist in vertical venting
of methane. Given all of these considerations, the possibility of a methane explosion as part of
the on-site burial management option is considered unlikely and is not evaluated as part of the
assessment.
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
3.5, Composting
The conceptual model for the composting option is shown in Figure 3.5.1. According to Looper
(2001), composting of dairy cow carcasses generally takes six to eight months, with 90% of the
flesh decomposed after eight weeks. Carcasses are difficult to find in the pile after four months,
with only a few bones present.
In this management option, the carcasses are placed in outdoor composting windrows that are
constructed according to specifications provided by USDA (2005). Carcasses are placed on a
base layer and covered with a 2 ft (0.6 m) thick layer of bulking material (e.g., woodchips) on the
top and all sides. For large animals, Glanville et al. (2006) recommends placing one U.S. ton
(907 kg) of carcass, in a single layer, per 8 ft (2.4 m) of windrow. Using this recommendation,
the total length of windrow for 45, 359 kg (50 U.S. tons) of large animal carcasses is 122 m (400
ft). The exposure assessment assumes two 16 ft (4.9 m) wide by 60 m (200 ft) long windrows.
Based on minimum siting recommendations in NABCC (2004) and USDA (2015), the
assessment assumed windrow construction occurs in a well-drained area that is at least 3 ft (90
cm) above the high water table level or bedrock and at least 200 ft (61 m) horizontally from a
water body.
The windrow is assumed to be placed on bare earth where any liquid not retained by a two-foot
base layer of woodchips could leach to soil and groundwater. Gases liberated by decomposition
diffuse upward through the bulking material to the atmosphere. The elevated temperatures (e.g.,
at least 55°C (131°F) for three or more days) associated with thermophilic microbial digestion of
carcass materials produced in the compost pile can deactivate many kinds of pathogenic
microbes (see Section 2.4.2 for more information) (Schwartz and Bonhotal 2014). The
assessment assumes most pathogens are inactivated by the time the compost is processed as a
product that can be applied in an on-site agricultural field in accordance with a nutrient
management plan. Transport of chemicals and any surviving microbes from the compost
application site can occur by runoff/erosion to the lake, leaching to groundwater (reaching the
well) and, subsequently, to the lake and aquatic food web. Other specific assumptions used to
model the composting option are shown Table 3.5.1.
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
Natural Disaster
1 On-site Transportation
Mortalities
Composting
Air
Stomatal
Uptake
Terrestrial
Plants
Ingestio
Root uptake
Inhalation
Livestock
Leaching from
Compost Windrows
&
Application of Finished
Compost to Soil
Erosion & Runoff
Incidental
Ingestion
Ingestion
On-site Lake
Uptake,
bioaccumulation
Leaching
Surface Water
Recharge
Sedimentation,
' Resuspension, &
I Diffusive Exchange
Aquatic
Life
Groundwater
Ingestion &
Inhalation
Well
Water
Uptake,
bioaccumulation
Ingestion
Humans
Ingestion
Figure 3.5.1. Conceptual model of exposure pathways from livestock carcass composting.
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
Table 3.5.1. Assumptions for the Composting Management Option
Conceptual Model
Feature
Assumptions
Compost Windrow
Design
¦ Composting is performed on bare earth at a site with 2-4% grade (USDA 2005, 2015).
¦ Carcasses are composted in two windrows that are 4.9 m (16 ft) wide by 61 m (200 ft)
long.
¦ An initial layer of bulking material (e.g., woodchips) 2 ft deep are placed across the
entire base of the eventual windrow (USDA 2005).
¦ An additional two feet of bulking material are placed on the sides and top of the
windrow (USDA 2005).
¦ Runoff from the windrows will be contained with hay bales.
¦ Most pathogens are inactivated by temperatures of at least 131°F (55°C) for at least
three days of composting (USDA 2015). Spore-forming pathogens and prions might
not be inactivated under these standard composting conditions.
¦ Releases to air from windrow turning are not evaluated. Windrows for cattle
composting are not turned; windrows for poultry might be turned one time after
pathogens are likely to be inactivated.
Air Pathways
¦ Gases generated by carcass decomposition diffuse upward through the top cover of
woodchips to air, where they quickly disperse to non-hazardous levels. Biological
agents and non-volatile chemicals will be contained by the bulking material (e.g.,
woodchips).
¦ Inhalation by livestock will not be included in the exposure assessment (see Table
3.1.1).
Soil Pathways
¦ The base layer of bulking material beneath the windrows limits contamination of
groundwater. Woodchips used as carbon bulking material absorb all but 5% of the
liquid released from the carcasses inside the windrow (Glanville et al. 2006). This
leakage can seep through soil to groundwater.
Surface Water,
Sediment, and
Aquatic Life
¦ Agents from composted carcasses can reach the lake only via runoff/erosion from the
compost application site (not from the windrow itself).
Production of Food
on the Farm
¦ For this assessment, compost is applied to a field according to a federal- or state-
approved nutrient management plan and crops human consumption are grown in that
field.
1.5.1. Leaching to Groundwater
As described in Section 3.4.1, a large amount of fluid (approximately 33% of the carcass mass in
the first 2 months) is released from decomposing carcasses. While carcass burial methods
typically do not include a means to contain leachate, properly constructed compost piles include
sufficient bulking materials to trap and absorb leachate (Payne et al. 2015). The bulking material
effectively acts as a sorbent, allowing water to evaporate while the bulk of the minerals and non-
volatile organic and inorganic compounds remain in the bulking material, which later is mixed
into the finished compost. Leachate from the fluids in carcasses alone (approximately 65% of the
fresh carcass mass) should be captured in the bulking material for the most part. Using corn
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
stalks as the sorbent bulking material, researchers including Glanville et al. (2006) and
Donaldson et al. (2012) found the volume of leachate from experimental compost windrows to
be no more than 5% of precipitation falling (500-600 mm) on the windrows (i.e., the bulking
material facilitated evaporation of water back into the air for 95% of the rainfall). The cattle
windrows contained the equivalent of 90 mm rainfall if spread evenly over the area directly
beneath the carcasses. That is in addition to the 530 and 590 mm of precipitation measured
during two trials. However, the total depth of leachate captured beneath the test units ranged
from 7 to 29 mm. Across the trials, leachate depths never exceeded 1-5% of the accumulated
precipitation (Glanville et al. 2006; Payne et al. 2015). Contaminants were detected in soils
below the windrows, but increases in total carbon and nitrogen (Table 3.5.2), limited to the top
15 cm of soil under the compost pile, were estimated to be less than 8% of the total carbon in the
top 15 cm of soil. Based on those studies, it is assumed that at least 95% of the contaminant mass
associated with the composting carcasses was present in the finished compost.
In soils beneath compost piles constructed with various carbon-based bulking materials (e.g.,
corn silage, ground cornstalks), Glanville et al. (2006) detected leached chloride at all depths
measured (up to 120 cm). Chloride is not considered a serious water pollutant, but is an indicator
of leachate movement because it does not absorb to soil and is very mobile in the environment
(Glanville et al. 2006).
Table 3.5.2. Change in Chemical Concentrations Pre- and Post-Composting Cattle
Carcasses using Corn Stalks (Glanville et al. 2006)
Depth Interval
Beneath Compost
Chemical Concentrations in Top 120
cm of Soil Prior to Composting (mg/kg
dw)
Change in Chemical Concentration (post
composting minus pre composting
concentration) (mg/kg dw)
Pile (cm)
Ammonia N
Nitrate N
Chloride
Ammonia N
Nitrate N
Chloride
0-15
5.2±5.1
12.5±9.4
55.0±33.0
302±368*
2.8±28.7
79.2±71.3*
15-30
3.2±2.6
8.4±6.7
56.2±30.5
41.5±60.2
6.2±29.1
47.4:41.7*
30-45
2.9±1.8
6.4±6.7
58.5±38.0
4.8±11.2
7.6±25.6
18.7±28.3
45-60
2.5±1.5
6.0±6.4
50.9±48.2
4.0±13.5
7.2±23.8
31.8±74.1*
60-90
1.8±1.4
6.5±7.1
25.6±20.3
0.7±6.2
3.7±22.6
25.9±49.6*
90-120
1.6±1.3
7.1±6.7
21.8±15.2
2.5±14.1
1.1±14.8
16.5±39.7*
Abbreviations: dw = dry weight.
* Indicates that increase is significantly different from zero.
Other leachate chemicals monitored by Glanville et al. (2006) appear to have been
sorbed/exchanged by soil, with moderate increases in ammonia nitrogen (Table 3.5.2) and total
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
carbon in the top 15 cm of the soil. Based on these findings, the soil beneath the windrow is
assumed to further attenuate the potential for contamination of groundwater.
1.5.2, Releases to Air front the Windrow
The layer of bulking material placed over and around composting carcasses allows for vapors to
diffuse out of the windrow while containing particles, including microbes. Sources that discuss
air quality from livestock composting generally focus on odor generation and vapors including
hydrogen sulfide and ammonia. Glanville et al. (2006), for example, reported odor levels within
the first four months of composting were similar to those reported for pond water (200-300
ODT). This volumetric ratio of fresh air to sample was at the lowest level that olfactometry
panelists could detect an odor. These levels are quite low compared with manure-related
facilities (4,000 ODT). Glanville and colleagues concluded that properly managed emergency
mortality composting would not present odor nuisance problems.
1.5.3. Application of Compost to Soil
As described above and shown in Figure 3.5.1, the finished compost was assumed to be applied
to soil on site. The rate of finished compost application to soil (i.e., tons of compost per acre) and
the total area of soil receiving compost assume the nitrogen (N) content of the compost is at an
agronomic rate, ostensibly following the farm's nutrient management plan. An agronomic rate of
application occurs when the nutrient content added to the soil does not exceed the uptake
capabilities of crops to be planted at the site, nor does it result in fertilizer burn (NABCC 2004).
Agronomic fertilization rates also help to protect air, soil, and water quality. For example,
nutrients supplied in excess of the agronomic rate may run off or leach to surface water, causing
eutrophication, or to groundwater degrading its quality.
Agronomic rate calculations require information about the nutrient content of the fertilizer or soil
amendment and the nutrient requirements of intended crops, if any. Tables 3.5.3 and 3.5.4
provide nutrient content values reported for finished cattle and hog compost, respectively. The
agronomic rate of application is based on the lower ranges of nitrogen content for cattle compost
in Table 3.5.3, specifically 5 kg of potentially available nitrogen per U.S. ton of compost. The
lower end of the reported range was used because it results in a higher rate of compost
application per acre, and higher chemical loadings, than the higher end of the reported range.
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
Because the hypothetical farm is modeled with meteorological data from Iowa (see Section
2.3.1), the scenario also uses assumptions about the nutrient requirements of soils and crops in
Iowa. The Iowa Water Environment Association (IAWEA) recommends nitrogen requirements
for both consumer (i.e., corn, wheat, oats) and non-consumer crops (i.e., various forage grasses)
(IAWEA 2011). The ranges of IAWEA-recommended values for various forage grasses are
presented in Table 3.5.5. As a conservative assumption, the upper bound from the grass with the
highest nitrogen requirement was selected as the value for use in the analysis (cool season tall
grass, requiring 120 lb N/ac or 135 kg N/ha). This approach does not assume additional nitrogen
credits to the soil (i.e., commercial fertilizers, previous legume crop growth), and consequently,
the entire nitrogen requirement is met through the application of compost.
Table 3.5.3. Nutrient Content of the Cattle Carcass Compost (Kube 2002 as cited in
NABCC 2004)
Nutrient
kg of Nutrients/U.S. ton (2,000 lb) of Compost (kg/tonne)
Total Kjeldahl Nitrogen (TKN-N)
10-25 (11-27.6)
Potentially Available Nitrogen (N)
5-15 (5.5-16.5)
Phosphorus (P)
2-20 (2.2-22)
Potassium (K)
4-20 (4.4-22)
Abbreviations: lb = pound; tonne = metric ton.
Table 3.5.4. Nutrient Content of Hog Carcass Compost (McGahan 2002 as cited in NABCC
2004)
Nutrient
Percent (%)
kg/tonne
Total Kjeldahl Nitrogen (TKN-N)
1.28
13.0
Ammonia Nitrogen (NH3-N)
0.22
2.00
Phosphorus (P)
0.27
2.84
Potassium (K)
0.28
2.90
Abbreviations: tonne = metric ton.
Table 3.5.5. Nitrogen Requirements for Forage Grasses in Iowa (IAWEA 2011)
Forage Type
lb N/ac (kg N/ha)
Cool season tall grass
100-120(112-135)
Blue grass
60-80 (67-90)
Sorghum-sudan
80 (90)
Legume grass
40 (45)
Warm season grass
90(101)
Abbreviations: lb = pound; ac = acre; ha = hectare.
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
In addition to the agronomic rate, an estimate of the final quantity of compost is needed to
calculate the total area to which the compost could be applied. The final volume of compost is
estimated based on the initial volume and the volume reduction at the completion of composting.
Langston et al. (2002 as cited in NABCC 2004) and Kube (2002 as cited in NABCC 2004) found
that after three months of composting, the final volume of swine and cattle carcasses was 20%
and 25% less, respectively, than the original volumes. As described earlier, the initial volume of
the windrows is estimated to be 357 m3. Assuming that the final volume of compost is 25% less
than the initial volume, the estimated final volume is 268 m3. As advised by NABCC (2004), the
ratio of bulking material to carcasses should result in a final compost mixture with a bulk density
that does not exceed 600 kg/m3 (37.5 lb/ft3). Applying this upper limit density to the final
volume of compost, the estimated final mass of compost applied to a field is 160,650 kg (161
tonnes or 177 U.S. tons). For the agronomic rate calculations, the weight of the compost must be
expressed in dry weight. According to Chen et al. (2012), the moisture content of finished
compost is typically 40%. With this assumption, the dry weight of the compost is 96.4 tonnes
(106 U.S. tons).
Using the above assumptions, the total area of compost application is calculated with the
following equation:
Total Area = * dry metric tons compost Eqn. 3.1
where:
kg available N = 5.5 kg N/dry tonne of compost
kg N required = 135 kg N/ha
dry tonnes of compost = 96.4 tonnes
With this approach, the estimated area over which the finished compost can be applied is about 4
ha (-40,000 m2 or 10 ac). This amounts to an application rate of about 24 dry tonnes of compost
per hectare.
A final consideration in evaluating the compost application area is the amount of phosphorus
added to the soil as the result of agronomic nitrogen management. Based on the application rate
estimated above and the reported range of phosphorus in finished compost (Table 3.5.3), the
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
addition of phosphorus would range from 52.8 to 528 kg/ha. Although nutrient requirements are
site-specific, the USEPA Part 503 Biosolids Rule, part 24 requires compost application to be
discontinued if the phosphorus content of the soil reaches 300 lb/ac (336 kg/ha). This indicates
that phosphorus additions, instead of nitrogen additions, might limit the compost application rate
in some cases. In those cases, the application rate would be lower than estimated above based on
the nitrogen content.
Reported concentrations of chemicals in finished livestock compost are available for nutrients
(see Tables 3.5.3 and 3.5.4) and veterinary drugs. According to a literature summary by Schwarz
and Bonhotal (2014), non-steroidal anti-inflammatory drugs (NSAID) appear to not persist
during livestock composting. However, there is evidence that sodium pentobarbital, a commonly
used euthanasia drug, is persistent throughout composting (Payne et al. 2015). Euthanasia drugs
are assumed to not be present in livestock killed by a natural disaster.
Because limited data were identified on the concentrations of metals in finished compost,
emission factors for carcass incineration reported by Chen et al. (2004) are used as surrogate data
to estimate metals added to soil in the application of finished compost. As described in Sections
3.3 and 3.4, Chen et al. (2004) reported metal emission factors (i.e., mg element per kg of carcass
incinerated) for bottom and fly ash from the HOWI and LIWI incinerators. Assuming that all of
the metal content in the incinerated carcasses is retained in either the bottom or fly ash, and that
all of the metal content in composted carcasses either remains in the finished compost or leaches
to the ground below, the data from Chen et al. (2004) can be used to estimate the metal content
of the finished compost.
Table 3.5.6 shows the total amount of metals estimated in the bottom and fly ash from
incineration of 50 tons of carcasses. Because the assumption that all of the metal content in the
incinerated carcasses is retained in ash is likely an overestimation, the greater metal abundance
estimate for the HOWI or LIWI incinerators (see the "Max" column in Table 3.5.6) form the
basis for the compost metal estimates. The total amount of the metals, converted from mg to g,
were then divided by the total area of compost application (estimated above) to calculate the
estimated loading of the metals to soil in g/m2
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Table 3.5.6. Estimated Loading of Metals to Soil with Compost Application
Element
mg in Bottom and Fly Ash (surrogate for total element in
carcasses)
Loading Rate to
Soil (g/m2)
HOWI
LIWI
Max
Cadmium
1.5E+04
1.8E+03
1.5E+04
3.9E-04
Chromium
2.6E+05
1.7E+05
2.6E+05
6.7E-03
Copper
1.1E+06
5.4E+05
1.1E+06
2.7E-02
Iron
1.0E+06
1.9E+07
1.9E+07
4.7E-01
Lead
8.2E+04
1.6E+06
1.6E+06
4.1E-02
Manganese
1.1E+05
3.9E+05
3.9E+05
9.9E-03
Nickel
3.9E+05
3.3E+05
3.9E+05
9.8E-03
Zinc
1.7E+05
4.1E+06
4.1E+06
1.0E-01
Abbreviations: HOWI = hog farm waste incinerator; LIWI = livestock disease control incinerator; max = maximum.
This section reviews pertinent aspects of all the carcass management options and specifically
identifies assumptions used to estimate chemical and microbial releases to air, soil, and water.
The conceptual models identify all potential pathways regardless of whether or not they are part
of the quantitative exposure modeling. The next section describes data and methods used to
model the fate of chemicals in the identified exposure pathways. Exposure estimation for
chemicals and microbes is presented in Sections 5 and 6.
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4, ("hemic and Transport
This section describes approaches used to evaluate the fate and transport of chemicals in abiotic
and biotic environmental media following their release from livestock carcass management
options, as described in Section 3. The modeling approaches use existing, peer-reviewed
modeling tools and frameworks for most potential exposure pathways. This includes those
involving air dispersion and deposition, soil erosion and runoff to surface water, bioaccumulation
in the aquatic food web, and uptake by terrestrial plants, crops, and livestock from air and soils.
Modeling approaches estimate leaching to groundwater used as drinking water and groundwater
recharge to surface water. Separate approaches assess exposure to chemicals and microbes
because most chemical fate and transport models do not evaluate the environmental fate and
transport of microbes or microbe-sized abiotic particles.
Air concentrations and wet, dry, and total deposition resulting from chemical releases to air from
open-pyre burning and air-curtain burning of carcasses are modeled with American
Meteorological Society/USEPA Regulatory Model air dispersion model AERMOD (version
14134). Chemical fate and transport in surface soil, surface water, and as food is produced and
consumed on the farm are modeled with algorithms, default environmental assumptions, and
chemical data from USEPA's (2005a) Human Health Risk Assessment Protocol (HHRAP) for
Hazardous Waste Combustion Facilities. HHRAP is a peer-reviewed environmental modeling
framework developed, refined, and used by USEPA's Office of Land and Emergency
Management (OLEM) (formerly Office of Solid Waste and Emergency Response) to estimate,
for chemicals released initially to air, their further transport and fate in soils, surface water,
terrestrial plants and animals, and to estimate human ingestion of chemicals in food and soils.
Concentrations of chemicals in fish are estimated by modeling uptake from surface water and
sediment followed by accumulation through an aquatic food web. Separate aquatic food web
modeling approaches were required for organic and inorganic chemicals. Bioaccumulation of
nonionic organic chemicals was modeled with AQUAWEB, a steady-state solution model of
aquatic bioaccumulation created by Arnot and Gobas (2004). AQUAWEB was not designed to
model the behavior of inorganic chemicals, including metals, in aquatic food webs. For metals
included in the assessment, bioaccumulation to game and pan fish is estimated using previously-
published bioaccumulation factors (BAFs).
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HHRAP and the other modeling frameworks described above do not include equations to
simulate chemical fate and transport in subsurface soil and groundwater, or to estimate chemical
loading to surface water from groundwater. Modeling in these environmental compartments is
needed to evaluate leaching from buried carcasses, compost windrows, temporary carcass
storage piles, and combustion ash buried on-site. Leaching from combustion ash to groundwater
is modeled using a health-protective, screening-level approach in which Kd values (i.e.,
chemical-specific soil-water partitioning coefficients) estimate the leaching of chemicals from
the ash to infiltrating precipitation and sorption of chemicals from leachate to subsurface soil. A
similar approach is used to model groundwater contamination from carcass burial and leaching
from compost windrows and carcass storage piles.
Sections 4.1 through 4.6 describe the modeling methods and results for specific media
compartments.
4.1. Air
As described in Section 3, the release of particle-bound chemicals to air is identified in the
conceptual models for the combustion-based management options. In addition, vapor emissions
to air are identified in the conceptual models for burial and composting, as well as the temporary
carcass storage pile that is included in all management options. These gas emissions are
primarily carbon dioxide, hydrogen sulfide, ammonia, methane, and malodorous gases. The
passive release of these vapors occurs over a broad area (e.g., diffused over the 2.1 m by 91.4 m
burial trench) with dilution in outdoor air. In this situation, it is reasonable to assume these
chemicals are unlikely to reach the acute effects concentrations that pose health risks to humans
or livestock. For this reason, the assessment does not model the chemical fate and transport of
these vapor emissions to air.
This assessment uses AERMOD (version 14134)8 to model air concentrations and wet, dry, and
total deposition resulting from chemical releases to the air from the use of open-pyre burning and
air-curtain burning. As shown in Table 4.1.1, the open pyre is represented as a line of five point
sources spaced at 20 m intervals, which covers most of the 91 m length of the pyre. The air-
curtain burner is represented as a single point source The relatively small length of the air-curtain
8 Complete documentation of AERMOD and related tools, including AERMOD, AERMET, and AERSURFACE, is available at
http://www3.epa. gov/scramOO 1/dispersion prefrec.htm.
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
firebox (i.e., 8.3 m) does not necessitate adding additional point sources. The assessment
assumes emissions originate at the height of the combustion units and from areas with diameters
equal to the width of the combustion units. For the air-curtain burner, the assessment uses the
dimensions of the fire box9. Release heights and diameters are shown in Table 4.1.1 (exit-gas
temperatures and velocities are discussed later in this section).
Table 4.1.1. Parameterization of Combustion Units in AERMOD
Combustion
Unit
Source Type
Height (m)
"Stack"
Diameter (m)
Exit gas
Temperature
(°C)
Exit gas
Velocity (m/s)
Open pyre
Point
(5 at 20 m
spacing)
1.8
2.44
550
3.9
Air-curtain
burner
Point (1)
2.5
2.6
550
7.8
Abbreviations: s = second.
AERMET is the meteorological pre-processor for the air dispersion model used within the
exposure assessment, AERMOD. Both AERMET and AERMOD require values for three
parameters not typically available from meteorological stations: site albedo, surface roughness,
and Bowen ratio.10 This assessment uses USEPA's AERSURFACE pre-processor to estimate
values for these three parameters. It samples land cover around a site and, along with inputs
regarding climatological conditions, uses look-up tables to estimate albedo, surface roughness,
and Bowen ratio for the site. This assessment assumes land cover near the hypothetical farm is
representative of agricultural areas surrounding Iowa City, Iowa, and is not specific to an actual
location. Using this assumed land cover (shown in Table 4.1.2), and information on a local
climate in Iowa (e.g., not arid; not near an airport; season assignments as shown in Table 4.1.3),
the AERSURFACE lookup tables (version 1/6/2013) estimate albedo, surface roughness, and
Bowen ratio for the hypothetical farm site. Those estimates include wetness data for 2014, when
January and March received considerably less precipitation than normal, and April, June, and
September received considerably more precipitation than normal. Table 4.1.4 summarizes the
precipitation information. Approximately 97 cm of rain or snow fell in 2014 during 168
9 See the overall air-curtain-bumer dimensions at http://www.airbumers.com/DATA-FILES Print/ab-s327 Specs PRNT.pdf.
111 In meteorology, albedo is a measure of the reflectivity of the earth's surface. In air dispersion modeling, albedo can be used to
model the thermodynamic interaction between the land or water surface and the atmosphere. Thermodynamics in an air
dispersion model also may use the Bowen ratio, which is an indicator of heat transfer between air and water. An indicator of the
land cover, surface roughness length, affects the movement of air above the land or water surface.
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
individual precipitation events lasting a total of 435 hours. That is equivalent to 968 L/m2 for the
year.
Table 4.1.2. Land Cover Surrounding Hypothetical Farm, with Percent Area Covered
Land cover Category
Percent of Area Around Site (%)
Open Water
1
Developed, Open Space
3
Developed, Low Intensity
2
Deciduous Forest
5
Grassland/Herbaceous
10
Pasture/Hay
30
Cultivated Crops
45
Woody Wetlands
3
Emergent Herbaceous Wetlands
1
Table 4.1.3. Seasons at the Hypothetical Farm
Month
Season
January
Winter with continuous snow cover
February
Winter with continuous snow cover
March
Winter with no snow
April
Transitional spring with partial green coverage
May
Transitional spring with partial green coverage
June
Summer with lush vegetation
July
Summer with lush vegetation
August
Summer with lush vegetation
September
Autumn before frost and harvest
October
Late autumn after frost or harvest
November
Late autumn after frost or harvest
December
Winter with continuous snow cover
Wind conditions at Iowa City in 2014 are summarized in the wind rose diagram shown as Figure
4.1.1. Winds blew from the south approximately 14% of the time, from the west approximately
15% of the time, from the southeast 20% of the time, and from the northwest 20% of the time.
Inhalation receptors are located in the predominant downwind direction (southeast) during the
two days of carcass burning. In addition, the lake is assumed to be southeast of the pyre or air-
curtain burner location.
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
Table 4.1.4. Summary of Precipitation Data for Iowa City Used in This Assessment
Parameter
Value (units)
Total annual precipitation
96.84 (cm/yr)
Number of rain events
168 (events/yr)
Total duration precipitation
435 (hr/yr)
Precipitation per event
0.5764 (cm/event)
Precipitation per hour of rain
0.2226 (cm/per hour of rain)
Average hours per event
2.6 (hr/event)
Water volume per event
5764 (centimeters [cm]3/m2)
Water volume per year
968.4 (L/nf)
Abbreviations: yr = year; hr = hour.
WIND SPEED
(m/s)
>= 10.0
B 7.5-10.0
B 5.0- 7.5
r~H 4.0- 5.0
I I 3.0- 4.0
| B 2.0- 3.0
HI 1°-20
I I 0.0- 1.0
Calms: 0.00%
Figure 4.1.1. Wind rose for Iowa City in 2014.
Combustion was modeled as being from point sources because they are the only source type in
AERMOD that explicitly uses data on exit-gas temperature and exit-gas velocity to calculate the
plume rise of buoyant and/or high-velocity emissions. In this assessment, the emissions will
exhibit significant buoyancy that is driven by the high temperature of the combustion events. The
air-curtain burner emissions escape at 7.8 m/s, based on measurements from a sampling flue
constructed over an air-curtain-incinerator pit burning cattle carcasses (see Table 14 of SKM,
2005). In contrast, open pyres lack the artificial wind current created by an air-curtain burner.
The assessment assumes one-half of that velocity (i.e., 3.9 m/s) for open-pyre emissions.
NORTI
SOUTI
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
Information from the literature suggests that temperatures of open pyres might be within the
range of 300 to 400°C (Chen et al. 2004), with temperatures from 421 to 524°C needed to ignite
coal and from 260 to 593°C needed to fully burn wood (Bartok 2003). With coal and wood used
as fuels, the open pyres in this assessment were modeled with an exit-gas temperature of 550°C.
For a trench air-curtain burner trial in New Zealand, temperatures measured above the flames in
ranged from 140 to 850°C (SKM 2005). Given that large range of potential near exit-gas
temperatures, the air-curtain burners in this assessment were modeled with the same exit-gas
temperature as open pyres (i.e., 550°C) deemed adequate to fully burn the wood fuel used in the
burners.
For the on-site combustion options, data on vapor-phase and particle-phase emissions of metals
are from Chen et al. (2004). Although the data source included vapor-phase measurements (Chen
et al. 2004), the measurements were taken inside the flue where temperatures were relatively
high. The assessment assumes that metal vapors coagulate when cooled in ambient air to form
aerosol particles that subsequently sorb to larger air-borne ash particles (based on Linak and
Wendt 1993). The modeling initially sums the vapor-phase and particulate-phase emission
estimates, and continues the modeling process entirely as particulate-phase. This allows use of
the simpler of AERMOD's two- particle-deposition schemes, where the mass-mean particulate
diameter and the fraction of particulate mass that is PM2.5 are specified for each chemical from
each combusted material. This simpler method is recommended when the particle-size
distribution is not well known, and when less than about 10% of particles by mass are believed to
be larger than PM10. This is the case for all chemicals from all combusted materials, except for
metals emitted from coal. For coal, the estimates of mass fractions and densities of several
classes of particulate diameter ranging from 0.1 |im to 25 |im are available (Bond et al. 2002, see
Appendix D, Table D. 1, for the particle-size settings used in AERMOD).
For deposition of chemicals released during on-site combustion activities that remain in vapor-
phase at ambient temperatures, the assessment uses estimates of chemical diffusivity in air,
diffusivity in water, Henry's Law Constant (HLC), and cuticular resistance to uptake by lipids
for individual leaves, as shown in Appendix D, Table D.2. The primary land cover is defined as
"agricultural land."
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
The modeled emission rates of particle-phase and vapor-phase chemicals, and of particle-phase
metals from on-site combustion activities, are in Appendix D, Table D.3. These emission rates
correspond to the emission factors (see Sections 3.1 and 3.2) multiplied by the mass of
combusted material and divided by a 48 hr combustion period.
The modeling receptors are characterized by a Cartesian grid of points at ground level, spaced
250 m apart, on a 6 km by 6 km square centered on the middle of the open pyre or air-curtain
burner sources. Concentrations of particles in air are modeled at an approximate breathing height
of 1.8 m, and deposition fluxes are modeled at ground level (i.e., 0 m height). Figure 4.1.2
depicts the annual-total modeled deposition of the total chemical emissions from open-pyre and
air-curtain-burning sources that are operating continuously and based on actual, hourly
meteorology. The receptor labeling indicates the ranking of relative deposition amounts, with 1
indicating the location receiving the highest deposition. The shading corresponds to relative
deposition intensity, from higher amounts in purples and oranges to much lower amounts in
blues. The 36 km2 modeling domain is located where the deposition rates are highest over the
course of the year. The maxima from depositions and the modeled concentrations of emissions in
air are highly unlikely to occur outside of this domain. The 250 m spacing gives 16 different
spatial estimates of air concentrations and deposition fluxes for each square kilometer. This
spatial resolution allows deposition to the hypothetical lake (at 6 locations), and the hypothetical
watershed (at approximately 32 locations).
According to the annual deposition totals plotted in Figure 4.1.2, wind conditions will tend to
concentrate deposition of chemicals from the air along an axis from northwest of the combustion
source to southeast (as expected based on the wind rose shown in Figure 4.1.1). According to the
modeling and the local meteorology data, the locations with the highest deposited mass, most
often will be within 600 m of the center of the combustion unit and generally to the southeast.
The hypothetical lake (approximately 40.5 ha) was set directly southeast of the source (see blue
polygon in Figure 4.1.2), and its hypothetical watershed (approximately 202 ha) surrounds the
lake on three sides (see red polygon in Figure 4.1.2). This placement is most likely to receive the
maximum amount of modeled chemical deposition for an open-pyre or air-curtain burner
combustion event at any time during the year. Concentrations of emitted chemicals and
deposition amounts are not estimated at the location of the combustion unit.
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
306 310 324 332 375 433 454:468
5421564*57,4*58
34 23
253 246
73 311 384
45W482I5
55,1*555
188 182 186 194
19 248 320 337 364 412 444 480 496(511*528
200 196 2
323 257-210 167 142 138 144
¦jHfltttl
330;263 205 159 122 102 101
350127,9 212 158 115 82 67
o
307 229 169 117 79 54
155 156157 170 193 256 27
107 114 113 124 150 197 217 251
411 435 447 4
51557/5
8 344¦366.B9BE».0B85M5®I5
71 78 80
106 146 173 208 25
5 358Ba 8«a«Ha8I50H»a
38 44 52 57 72 104 132 172 190 216 2
27 361
8-446*489*5
48,1p432 359 276 1
133 83 51
29 24 28 31 40 70 98 129 140 187 227 261 313 376-4273591488
495 443
316 238 175 105 60
32 16 14 18 26 55 75 90 125 14351
47 21 12vI10: 15 53 63N>76 89 112 137 168 202 241 288
86 59 33 46 .49' 56 43^48 65 93 120153 ,189'235£81«36
8 274 318
475-424 345 270 199 141 96
428 368
236 178 131
95fflH51BW343 28
165 121
85 61 35
108 94 68
/ 23 36. 62 92 123 161
" 30 39 66S.95 126 162 203 244 294
>
4 245 2
425 360 292 233 180 139
341 28
154 110 9^
176 147 149
27 58 84' 116 148 184 225 268 322
355 284 218
22 41/81 128 171 214 258 305 354
5*5501525 491 442 380 301 25
224 215 211 1510 00 91 69 42 37/50 73 111 164
278 331 38
450 413 362 326
293 2
65 185 145M36 127 97 /77 74 87 109 152 206 2
5661544
54:7*51r2!483 449 4
378 329 231 201 1
3 135 118 119 134 160 195 249 321 3
5*57,5155
5,15 4
64 247 23
166 174 181 213 252 303 36
4 352 335 334 328 314 283 254 230 223 226 240 27
215591554
536*5,10-4
340 309 286 282 28
8 339 381
596X59.0158 5158315
504 466 455 456 453 445 438 42
5-370 351 34
15*6,1
8*5321508
3*487*4
426 416 415 420 43
Notes: Shading corresponds to relative deposition amount (from higher amounts in purple and
orange to much lower amounts in blues). Shading scale uses unequal intervals to provide higher
resolution in areas of large gradients. Receptor labeling also corresponds relative to deposition
amount (1; highest amount). White area at center is the location of the source. Blue polygon
corresponds to the location of the hypothetical lake. Red polygon corresponds to the location of
the watershed of the hypothetical lake.
Figure 4.1.2 Modeled, annual-total deposited mass of chemicals emitted from open-pyre
and air-curtain burner units, using hourly meteorology.
The A ERMOD modeling assume the combustion units operated continuously every hour of the
year at a rate that would manage 46,359 kg (100 U.S. tons) of cattle every 48 hr (the length of a
combustion "event"). This approach allows only the meteorological conditions to change from
one hour or day to the next. This approach also enables calculation of the average concentration
of the chemicals, and total deposition, for any 48 hr period of the year (i.e., for a combustion
event that could begin at any hour of the year). For example, the event-average concentration of
the chemicals in the air and event-total deposition amounts are calculated for a combustion event
beginning at midnight on February Ist by averaging and totaling the hourly modeling results for
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
February 1st at 12 AM to February 3rd at 12 AM. This post-processing estimates event-average
concentrations of chemicals in the air, and event-total deposition amounts for 8,760 unique
combustion events, each beginning on a different hour of the year (365 d x 24 hr = 8,760 hr).
In practice, people try to avoid conducting open-pyre burning activities on windy days, and it is
not possible to keep pyres lit during heavy precipitation. Consequently, the modeling assumes
that burns do not occur during particularly windy or heavy precipitation periods. Such periods
are defined as having at least 10% of the combustion hours (i.e., at least 5 hr of a 48 hr
combustion event) with wind speeds of at least 8.94 m/s (20 mi/hr) and/or precipitation amounts
of at least 2.5 mm/hr (0.1 in/hr); i.e., at least 12.7 mm (0.5 in) for a 48 hr period. Using those
criteria, there were 1,428 total 48 hr periods when on-site combustion would not occur. These
periods are excluded from the results presented in this assessment. The modeling results
identified the location of the highest total deposition of emitted chemicals during any suitable 48
hr period. The results also identify the period leading to the greatest deposition to the lake and its
watershed. With further modeling, the assessment evaluates the corresponding impact of emitted
chemicals in terrestrial and aquatic media.
4.2. Surface Soil
The assessment estimates chemical concentrations reaching the surface soil from the
combustion-based management options and the composting management option. With the on-
site combustion of carcasses from a natural disaster, chemicals deposit from air to soil via
diffusion (vapor-phase) or by gravity (particle-phase). During the composting management
option, metals and other persistent chemicals present in the finished compost are applied to soil
with the compost. Fate and transport processes (e.g., mixing, runoff, erosion, plant root uptake)
affecting chemicals in the soil are modeled with USEPA's (2005a) HHRAP for Hazardous Waste
Combustion Facilities.11 HHRAP is a peer-reviewed environmental modeling framework
developed, refined, and used by USEPA's Office of Resource Conservation and Recovery
(formerly the Office of Solid Waste) to estimate chemical transport of chemicals released to air
from a point source and their subsequent fate and transport in soil, surface water, and terrestrial
plants and animals. HHRAP also estimates human exposure to chemicals ingested with food
11 Further information on HHRAP is available at: http://www3.epa.gov/epawaste/hazard/tsd/td/combust/riskvol.htm and
http://www3.epa.gov/epawaste/hazard/tsd/td/combust/risk.htm.
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
grown in or soils picked up within the modeled area of contamination. See Appendices D and G
for further information about the HHRAP methods applied in this project.
HHRAP is a method for performing multi-pathway, site-specific risk assessments for facilities
burning hazardous waste. However, the algorithms in HHRAP can be applied for sources other
than combustors. HHRAP is not a computerized model, but rather a collection of recommended
algorithms, default assumptions, and chemical data. This project uses applicable components of
HHRAP to create an HHRAP Soil and Surface Water Excel model, referred to hereafter as the
HHRAP SSW Model (or just SSW). This model includes HHRAP algorithms for the soil,
surface water, and sediment compartments, specifically those that evaluate loading and loss
processes via deposition, diffusion, erosion, runoff, leaching, volatilization, and sediment burial.
Appendix E provides details about the HHRAP algorithms included in the HHRAP SSW Model,
and Appendix F provides values of input parameters. The HHRAP modeling approach assumes
steady-state conditions within each biotic and abiotic media compartment (e.g., soil, surface
water, terrestrial plants), and chemical partitioning within a compartment (e.g., between soil
particles and soil pore water, between suspended sediment particles and the water column) is
calculated assuming equilibrium conditions. The HHRAP approach does not maintain a chemical
mass balance, and chemical feedback mechanisms are not included. For example, the
volatilization of a chemical from a water body does not affect the concentration of that chemical
in the air.
The HHRAP SSW Model calculates chemical concentrations in soil after an area receives
deposition of the chemical from the air or after compost is applied as a soil amendment. Inputs
required for these estimates include the depth of mixing in the soil, soil moisture content, and the
densities of the compost and receiving soils. All input value assumptions are listed in Appendix
F. Where appropriate, the SSW Model uses HHRAP default assumptions. For example, HHRAP
provides default assumptions for soil moisture at 0.2 milliliters (mL) water/cm3 soil and bulk-soil
density at 1,500 kg/m3 (93.6 lb/ft3) (surface soil, unsaturated).
Tables 4.2.1 and 4.2.2 present the chemical loading rates and resulting soil concentration
estimates for the combustion-based and composting management options, respectively. Soil
concentrations represent the concentration of chemicals after mixing the chemical loadings into
the surface soil and after a year of loss processes included in the HHRAP soil compartment
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
algorithms. The two combustion-based options assume no tillage, and the chemicals penetrate no
more than 2 cm (0.79 in) where they remain vulnerable to runoff and to erosion with soil
particles. The composting option uses the HHRAP default mixing depth for tilled soil of 20 cm
(7.9 in). In Table 4.2.1, concentrations of individual PAH compounds and dioxin/furan
congeners are totaled.
Table 4.2.1 Estimated Chemical Deposition from Air to Soil and Final Soil Concentrations
for Combustion-based Management Options
Chemical
Total Deposition: Wet and Dry Particle
Phase + Wet and Dry Vapor Phase (g/m2 yr)
Soil Chemical Concentration from
Total Deposition (mg/kg)
Open Burning
Air curtain Burning
Open Burning
Air curtain
Burning
Arsenic
2.8E-08
5.4E-09
1.3E-12
3.2E-13
Cadmium
4.4E-08
3.6E-08
1.4E-10
1.4E-10
Chromium
4.9E-07
1.7E-07
3.0E-10
1.3E-10
Copper
3.7E-07
1.9E-07
6.9E-10
4.2E-10
Iron
1.4E-04
1.0E-05
4.0E-04
3.3E-05
Lead
4.3E-07
1.7E-07
2.0E-08
9.6E-09
Manganese
1.3E-06
1.3E-05
3.8E-06
4.2E-05
Nickel
3.8E-07
7.8E-08
1.3E-09
3.2E-10
Zinc
2.8E-06
3.1E-06
8.8E-09
1.2E-08
Total Dioxins
4.2E-14
1.4E-12
1.2E-13
5.4E-12
Total PAHs
2.2E-06
5.7E-09
5.4E-06
1.7E-08
Abbreviations: yr = year; PAHs = polycyclic aromatic hydrocarbons.
Table 4.2.2 Estimated Chemical Loading and Final Soil Concentrations for the Composting
Management Option
Chemical
Loading to Soil (g/m2)
Soil Chemical Concentration (mg/kg)
Cadmium
3.9E-04
6.9E-05
Chromium
6.7E-03
2.4E-04
Copper
2.7E-02
2.8E-03
Iron
4.7E-01
7.8E-01
Lead
4.1E-02
4.8E-02
Manganese
9.9E-03
1.6E-02
Nickel
9.8E-03
1.9E-03
Zinc
1.0E-01
1.9E-02
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
4,3, Groundwater
Estimates of concentrations or amounts of chemicals in groundwater are needed to estimate
human exposure from use of well water in the home (e.g., drinking, cooking, and washing).
Groundwater concentrations or amounts of chemicals also allow estimation of the contribution of
groundwater transport of chemicals to the lake via recharge. The assessment estimates chemical
fate and transport in groundwater from the following sources:
1 Buried carcasses releasing liquids (leachate) that seeps into soil beneath the burial trench
¦ Buried combustion ash that leaches chemicals to infiltrating precipitation
1 Compost windrows leaking leachate from the carcasses that is not absorbed by the bulking
material
¦ The carcass storage pile releasing leachate to the ground below the pile as early stage
decomposition progresses
1,5,1, Leaching front Burled Carcasses
Cell lysis and degradation of tissues starts soon after death. As lysis progresses, free fluids and
gases begin to bloat the carcass. Fluids and gases escape via natural orifices and later via the skin
once its integrity is lost. The quantity of leachate is highest during the first week or two after
burial, depending on the ambient temperature and activity of the native microflora degrading the
carcass. Lower quantities of carcass body fluids continue to be released over the first two months
(Young et al. 2001).
As stated in Section 3.4.1, for 45,359 kg (50 U.S. tons) of carcasses, approximately 7,500 L of
fluid would be released in the first week, another approximately 7,500 L would be released over
the next 2 months, and the remaining fluids would leach more slowly, with some influence of
ambient precipitation infiltrating the burial trench and contributing to continued leaching. This
assessment assumes 60% of the weight of the carcasses, or approximately 27,000 kg, will be
leached as fluids during the first year after burial (Young et al. 2001). Assuming the leachate has
the same density as water (i.e., 1 kg/L), approximately 27,000 L is expected to be released from
the carcasses during the first year after burial.
Many states recommend or mandate minimum depths of unsaturated soil beneath carcass burial
pits to protect groundwater quality. These distances are as little as 1 ft (-0.3 m), but are more
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
typically 3 ft (~1 m) or more (NABCC 2004). Subsurface soils should sorb some of the
contaminants. To include "filtering" of chemicals by soil between the burial trench and the
groundwater aquifer, and to minimize the need for uncertain site-specific assumptions and highly
complex groundwater modeling, a health-protective, screening-level approach is adopted by this
project. Specifically, sorption of contaminants from the leachate to the soil is estimated with Kd
values, which are chemical-specific soil-water partitioning coefficients. The chemical-specific
Kd values are listed in Appendix G, along with further details about estimating leachate from the
burial trench to groundwater. No other attenuation or dilution processes are included in the
groundwater modeling. Once the leachate plume reaches groundwater, it is assumed to travel
horizontally in a constrained aquifer (i.e., a relatively impermeable layer of silt or clay
essentially prevents further downward movement of water).
To simulate the filtering of chemicals from the leachate to subsurface soil, it is necessary to
calculate the volume and dry weight of soil that would be saturated by the leachate amounts for
each time period. These estimates assume soil porosity of 20% and dry soil particle density of
2.7 g/cm3 (0.098 lb/ft3), both of which are default assumptions from HHRAP (USEPA 2005a).
Chemical partitioning between soil and leachate was estimated using the Kd equation:
^ _ mg [solid phase contaminant]/kg [soil] Eqn. 4.1
^ mg [aqueous phase contaminatn/L [water]
For brevity, the equation can be rewritten as:
Kd = (mgs/kgs)/(mga/La) Eqn. 4.2
where:
mgs = mg [solid-phase contaminant]
mga = mg [aqueous phase contaminant]
kgs = kg [soil dry weight]
La = L [volume of leachate]
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
Chemical-specific Kd values, are listed in Appendix G.
After passing through soil, mga equals the initial, pre-partitioning mass of chemical available
(mginit) minus the amount sorbed to the solid phase (mgs). For this approach, instant and
homogenous equilibrium is assumed between the solid and aqueous phases.
With the assumptions above, the equation above can be rewritten as follows:
Kd = (mgs/kgs)/((mginit - mgs)/La) Eqn. 4.3
The equation above is then solved for mgs, using the constant assumptions listed above, to
estimate the mass of chemical sorbed to soil.
mgs = {Kd * kgs * mginit)/(La + Kd* kgs) Eqn. 4.4
The mass of chemical remaining in the leachate after filtering by the soil is then mgint - mgs. This
is the chemical mass that enters the groundwater aquifer upgradient of the drinking water well
and on-site lake. Further information on this approach is presented in Appendix G.
1.5.2. Leaching from Burled Combustion Bottom-Ash
Figure 4.3.1 shows the site setting and conceptual approach used to estimate the leaching of
chemicals from buried bottom ash to groundwater. Chemical fate and transport in groundwater is
modeled using an approach similar to that described above for leaching from buried carcasses. In
the ash leaching approach, Kd values estimate the leaching of chemicals from the ash to
infiltrating precipitation with each rain event for a one-year period. As the leachate from each
rain event moves through the unsaturated zone of subsurface soil beneath the ash, a portion of
the chemicals in the leachate are filtered by the soil (i.e., sorb to soil particles) as estimated with
Kd values. The leaching calculations are shown in Appendix H.
Leaching from the ash is estimated for a series of rainfalls during the first year after ash burial.
At the hypothetical site, there were 168 "precipitation events" in 2014, with at total amount of
38.1 in (96.8 cm) (see Table 4.1.4). The average precipitation for the 168 events is 0.23 in (0.58
cm), and the average precipitation per ground area is 0.14 gal/ft2 (5.8 L/m2). This amount is used
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
to estimate leaching of chemicals from the bottom ash to the water that infiltrates it during each
precipitation event.
Leaching calculations also require estimates of the weight of ash per area (i.e., ft2 or m2) based
on the fuel amounts, combustion efficiencies, and ash placement areas for each combustion-
based option. For the open-pyre burning option, the weight of the ash per area is calculated as
3.07 lb/ft2 (15 kg/m2). Ash from air-curtain burning occupies a smaller area than that used by the
pyre, with a resulting weight per area of 16 lb/ft2 (78 kg/m2). See Appendix H for further
information about these values.
With each precipitation event, the Kd is applied to the contaminant mass in the ash to estimate
the fraction that partitions to the aqueous phase as rainfall percolates through subsurface soils
toward groundwater (i.e., "leachate"). The mass that does not partition to the aqueous phase
remains in the ash as the contaminant mass available to be carried down via percolation during
the next precipitation event.
\ *
I *
I *
l *
l *
Precipitation
V I 1
\ 1 1
\ I *
1 ^ 1
I ^ ^
1
I *
I *
I *
100 ft down gradient
Drinking
water
well
Ash
leaching from ash to
infiltrating precipitation
Leachate
Partitioning between
leachate and soil
Aquifer
Direction
of flow
Figure 4.3.1 Modeling scenario for chemical movement from buried combustion ash to
groundwater with percolation of water.
Similar to the partitioning approach used for the carcass burial scenario, chemicals carried
toward groundwater by rainfall percolating through the ash layer was estimated using Equation
4.2. In this use of the equation, the solid-phase material is ash (i.e., 15 kg of ash for open
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
burning, 78 kg of ash for air-curtain burning), and the aqueous volume is 5.8 L as discussed
above. The assessment assumes that after any loss of chemical in water percolating through the
ash, mgs equals the initial, pre-leaching mass of chemical available (rngmt) minus the amount
leached to the aqueous phase (mga). Equilibrium between the solid and aqueous phases is
assumed to occur instantly and homogenously throughout the ash layer.
With the assumptions above, the Equation 4.2 can be rewritten as follows:
Kd = (mginit - mga -h kgs)/(mga -h La) Eqn. 4.5
Equation 4.5 is then solved for mga, using the assumed constants, to estimate the mass of
chemicals carried with water percolating through the ash per rain event.
mga = (La * mginit)/(kgs *Kd + La) Eqn. 4.6
In addition, Equation 4.4 is used to estimate the amount of chemical adsorbed from the
percolating water to soil particles in the unsaturated zone after a precipitation event. For this
step, kgs is the dry weight of soil saturated by the 5.8 L of leachate per m2 The kgs value is
estimated as 62 kg, using default soil assumptions from HHRAP (USEPA 2005a), specifically a
soil porosity of 20% and a dry soil particle density of 2.7 g/cm3.
Subtracting the amount filtered by soil from the amount carried downward in rainwater
percolating through the buried ash yields the amount of chemical that reaches groundwater per
precipitation event. For each combustion-based option, this amount is calculated per m2 of ash
area. These amounts are multiplied by the whole ash areas to determine the total amount of
chemical leached to groundwater per rain event.
At the end of the first rain event, the amount of chemical reaching the groundwater divided by
the initial amount of chemical in the ash is the fraction of chemical "leached" ifieach). The
cumulative amount of chemical that reaches the groundwater after all rain events in the first year
is calculated with Equation 4.7:
ri — rT,ir, - /1 -Eon. 4.7
>' Stotal ~ 11 Heath 1 j M
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
A limitation that causes over-estimation by this approach is the adsorption capacity in subsurface
soil layers not being diminished by adsorption during earlier precipitation events. However,
because chemicals with a high affinity for binding with solids, including most PAHs and
dioxin/furans, move only short distances from buried bottom ash, this limitation is unlikely to be
significant for those chemicals. See Appendix H for further details about the approach for
estimating chemical leaching from buried bottom ash to groundwater.
1.5.3. Leaching from the Compost Windrow
Livestock compost windrows are constructed with a thick layer of carbon-based bulking material
(e.g., wood chips) that absorbs liquids released by the decomposing carcasses. Excess liquid can
be released if the bulking material layer is too thin or if the material does not have a sufficient
absorptive capacity (e.g., corn husks). The bottom layer of bulking material can absorb
precipitation only up to the point of saturation. As discussed in Section 3.5.1, Glanville et al.
(2006) and Donaldson et al. (2012) both reported volumes of leachate from experimental
compost windrows to not exceed 5% of the precipitation that falls on the windrows. Based on
that information, the assessment assumes that only 5% of the volume of fluids released by
decomposition will seep into the ground beneath the windrow. Specifically, the volume of
leachate released from buried carcasses during the first year (27,000 L) was multiplied by 5% to
estimate the approximate volume of fluid released to ground from the windrow (1,350 L).
Average chemical concentrations in leachate from carcass burial during the first year (Table
3.4.5 in Section 3.4.1) are used as the concentrations in the windrow leachate. Sorption of
leachate chemicals to soil in the unsaturated zone is estimated with the same Kd partitioning
approach used for carcass burial and leaching from buried bottom ash. See Appendix G for
further details.
1.5.4. Leaching from the Storage Pile
As a component of all carcass management options, the storage pile releases leachate to the
ground beneath it as decomposing carcasses release bodily fluids. The amount of fluid released
from the storage pile depends on the time after death. As discussed in Section 3.4.1, Young et al.
(2001) provided a basis for estimating the rate of liquid released during the early stages of
decomposition. In particular, approximately 7,500 L is expected to leak from the carcasses
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
during the first week averaging about 1,070 L of liquid leachate per day. In actuality, most of the
releases during the first week occur after the abdomen of an animal bursts from gas buildup.
According to the workshop experts (Section 2.5), the abdomen in a livestock carcass typically
bursts 3 to 4 days after death, with leachate releases occurring 3 to 7 days after death. Before the
abdomen bursts, liquid matter unrelated to decomposition (e.g., feces, urine, blood, ingesta,
serum, saliva) can be released (UM-CAHFS 2014). Because liquids could be released at varying
but unknown rates throughout the first post-mortem week, the total amount released during the
first week is averaged to calculate a daily rate.
The methods used to estimate leaching to groundwater from the storage pile are based on the
methods described above to estimate leaching from the burial trench. Chemical concentrations in
the storage pile leachate are assumed to be the same as the concentrations in leachate from buried
carcasses over the first week (Table 3.4.5 in Section 3.4.1), and the Kd partitioning approach
estimates the amount of leachate chemicals "filtered" by soil in the unsaturated zone. The
leachate chemicals not sorbed to soil particles enter the aquifer undiluted by water from
precipitation. The next section describes how the assessment uses this information to evaluate
potential chemical concentrations in drinking water. See Appendix G for further details.
1.5.5. Interception of Groundwater By Well
This section describes how leaching from the buried carcasses, buried combustion ash, the
compost windrow, and the carcass storage pile have the potential to contribute to concentrations
of chemicals in drinking water. The above sections (4.3.1 through 4.3.4) describe how the
assessment estimates chemical mass leached from these sources to the aquifer. To then estimate
how much of the chemical mass reaches a down-gradient drinking water well, the assessment
considers the proportion of the contaminated plume intercepted by the well. To do this, the
amount reaching the aquifer is multiplied by the percent of the contaminated plume intercepted
by the well, to calculate an interception fraction. The well's interception fractions are calculated
by dividing the well diameter by the horizontal width of the contaminant plume in the aquifer,
which, in turn, is equal to the width of the leachate source. This approach assumes the long side
of each source is perpendicular to the direction of groundwater flow, and that the plume does not
disperse horizontally over the relatively short distance between the source and the well (assumed
as 30.5 m or 100 ft). Figure 4.3.2 shows the conceptual configuration of this approach for
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
estimating the quantity of chemicals in leachate that reach the well downgradient from the burial
trench.
Burial Trench
E
lo
d
no
(Well
91.4 m
Burial Trench: 91.4 m
Well Diameter: 0.2 m
Figure not to scale
Figure 4.3.2. Well interception of leachate plume from burial trench.
The assumed plume widths are:
¦ Burial - The burial trench is 2.4 m wide by 91.4 m long, and is sited with the long
dimension perpendicular to the direction of groundwater flow. The width of the plume
equals the length of the trench, 91.4 m.
¦ Open burning - The length of the disposal area equals the length of the pyre, or 91.4 m
because ash is buried in place. The width of the groundwater plume also equals this
distance.
¦ Air-curtain burning - Ash is buried in a pit measuring 3.6 m by 11.4 m. Using the long
edge of the disposal area as the width of the plume, the width of the plume is 11.4 m.
¦ Composting - The width of the groundwater plume equals the length of the compost
windrow, 61m. The composting scenario includes two windrows of the same length. These
are assumed to be parallel and perpendicular to the direction of groundwater flow, with both
windrows contributing equally to the groundwater leaching. For the purpose of fate and
transport modeling, the two windrows are treated as a single source.
¦ Storage pile - The storage pile measures 2.4 m wide by 40.3 m long. The long edge is used
as the assumed width of the groundwater plume (40.3 m).
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
Well interception fractions are calculated using a "typical" standard well size identified from
recommendations by the Indiana State Department of Health. 12 Indiana recommends that all
wells should be encased (and water tight) for at least 25 ft (7.62 m) below the ground surface.
The inner pipe diameter can range from 5-10 in (12.7-24.5 cm). Based on this information, the
well is assumed to have an 8 in (0.20 m) well pipe diameter. The vertical distance over which the
well screening/packed gravel intercepts groundwater or an aquifer depends on desired flow rates;
this project assumes the entire depth of the confined groundwater or aquifer can intercept water
to be pumped to the surface. Table 4.3.1 shows the calculated well interception fractions.
Table 4.3.1. Summary of Calculations for Groundwater Well Intercept Fraction
Source
Well Diameter (m)
Plume Width (m)
Groundwater Well
Intercept Fraction
Burial Trench
0.2
91.4
0.0022
Burial of Ash from Open
Burning
0.2
91.4
0.0022
Burial of Ash from Air curtain
0.2
11.4
0.0180
Burning
Composting Windrow
0.2
61
0.0033
Carcass Storage Pile
0.2
40.3
0.0050
To estimate the potential for flowing groundwater to dilute chemicals that are intercepted by the
well, the assessment assumes water from the well provides the farm the average quantity of
water used per household in the United States. An average U.S. household uses more than 300
gal (1,136 L) per day.13 Chemical concentrations in drinking water are estimated by first
multiplying the chemical mass leached per time period (i.e., 1 day, 1 week, 60 days, 1 year),
discussed above, by the intercept factions, and then dividing the mass of chemical intercepted by
the amount of water withdrawn over the same time periods.
For the burial option, the assessment estimates average concentrations of chemicals in drinking
water for the first week, the first two months, and the first year following burial (Table 4.3.2).
12 http://www.in.gOv/isdl-i/23258.htm#Cl
13 https://www3.epa.gov/watersense/our water/water use todav.html
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
Table 4.3.2. Estimated Concentrations of Chemicals Leaching from Buried Carcasses That
Might Reach On-siteDrinking Water Well
Chemical Species
Concentration in Drinking Water(mg/L),
0.20 m Diameter Well Drawing 1,136 L/d
1st week
1st 60 days
1st year
Aluminum
6.0E-08
2.4E-08
5.5E-09
Ammonium1
1.6E+00
9.8E-01
6.1E-01
Barium
3.9E-07
2.8E-07
5.6E-08
Beryllium
nd
nd
nd
Bicarbonate
5.2E+01
1.6E+01
6.1E+00
Boron
nd
1.0E-04
3.7E-05
Cadmium
nd
nd
nd
Calcium
1.9E-02
4.7E-03
2.1E-03
Chloride
8.2E-01
3.3E-01
1.4E-01
Chromium
nd
nd
nd
Cobalt
1.2E-07
nd
1.2E-09
Copper
7.4E-08
5.2E-08
2.4E-08
Inorganic Carbon
1.4E+01
3.8E+00
1.3E+00
Organic Carbon
8.9E+01
2.2E+01
8.0E+00
Iron
9.0E-05
2.5E-05
6.6E-06
Lead
nd
nd
nd
Magnesium
9.4E-03
3.0E-03
1.1E-03
Manganese
4.1E-07
1.5E-07
5.5E-08
Molybdenum
5.7E-04
8.5E-05
1.0E-05
Nickel
3.3E-07
9.5E-08
1.3E-08
Nitrate/nitrite3
7.2E-03
1.7E-03
3.3E-04
Total Nitrogen
3.8E+01
7.3E+00
2.6E+00
Phosphorus
2.9E-01
1.5E-01
6.6E-02
Potassium
6.0E-01
2.6E-01
1.2E-01
Silicon13
9.1E-03
3.4E-03
1.3E-03
Sodium
5.0E-01
2.7E-01
1.1E-01
Strontium
2.2E-04
5.5E-05
1.6E-05
Sulfate
2.3E+00
1.1E+00
4.3E-01
Sulphur
3.8E-01
2.0E-01
9.4E-02
Titanium
6.3E-05
nd
4.7E-07
Zinc
3.0E-06
1.5E-06
5.6E-07
Zirconium
6.3E-05
nd
4.7E-07
Abbreviations: nd = not detected; d = day.
a As nitrogen (N). b Soluble silicon.
This corresponds to the time intervals of Pratt and Fonstad (2009). Estimates of drinking water
exposures are based only on the first year (i.e., leaching in the first year following carcass
management).The total chemical mass intercepted by the well on a daily basis from this release
is divided by the total annual water use and the number of days per year (i.e., 1,136 L/d x 365 d).
For chemical releases from buried ash and the compost windrows, the total mass of chemical
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
intercepted by the well is divided by the total water withdrawn per year for average annual
concentrations (Tables 4.3.3 and 4.3.4). For the storage pile, the amounts of chemicals leached to
groundwater are calculated as two days' worth of release at concentrations reported by Pratt and
Fonstad (2009) for the first week. The chemical amounts intercepted by the well are then divided
by the total annual water use (Table 4.3.4). See Appendix G and Appendix H for further details
about these calculations.
Table 4.3.3. Estimated Concentrations of Chemicals Leaching from Buried Ash That Might
Reach On-site Drinking Water Well
Chemical Species
Concentrations in Drinking Water (mg/L)
Typical Well (0.20 m Diameter and Drawing 1,136 L/d)
Open Burning
Air curtain Burning
Arsenic
4.8E-08
8.5E-08
Cadmium
7.7E-09
5.7E-09
Chromium
8.6E-06
1.4E-05
Copper
2.3E-08
2.8E-08
Iron
7.3E-05
8.0E-05
Lead
3.4E-10
6.0E-09
Manganese
4.0E-05
7.0E-05
Nickel
2.9E-07
3.8E-07
Zinc
1.8E-06
6.1E-06
Total Dioxins
3.1E-21
5.5E-21
Total PAHs
8.5E-12
2.2E-11
Abbreviations: d = day; PAHs = polycyclic aromatic hydrocarbon.
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
Table 4.3.4. Estimated Concentrations of Chemicals in Leachate fom a Carcass Storage
Pile or a Composting Windrow that Might Reach On-site Drinking Water Well from
Compost and Storage Pile
Chemical Species
Concentrations in Drinking Water (mg/L)
Typical Well (0.20 m Diameter and Drawing 1,136 L/d)
Compost Windrow
Carcass Storage Pile
Aluminum
4.1E-10
2.7E-09
Ammonium3
4.6E-02
5.2E-02
Barium
4.2E-09
1.7E-08
Bicarbonate
4.6E-01
8.1E-01
Boron
2.8E-06
nd
Calcium
1.6E-04
6.0E-04
Chloride
1.0E-02
2.6E-02
Cobalt
9.1E-11
5.3E-09
Copper
1.8E-09
3.3E-09
Inorganic Carbon
9.9E-02
1.8E-01
Organic Carbon
6.0E-01
1.1E+00
Iron
4.9E-07
4.0E-06
Magnesium
7.9E-05
3.0E-04
Manganese
4.1E-09
1.8E-08
Molybdenum
7.6E-07
1.8E-05
Nickel
9.9E-10
1.5E-08
Nitrate/nitrite3
2.5E-05
2.3E-04
Total Nitrogen
2.0E-01
4.7E-01
Phosphorus
4.9E-03
9.3E-03
Potassium
8.7E-03
1.9E-02
Silicon13
1.0E-04
2.9E-04
Sodium
8.5E-03
1.6E-02
Strontium
1.2E-06
7.0E-06
Sulfate
3.2E-02
5.7E-02
Sulphur
7.0E-03
1.2E-02
Titanium
3.5E-08
2.0E-06
Zinc
4.2E-08
1.3E-07
Zirconium
3.5E-08
2.0E-06
Abbreviations: nd = not detected; d = day.
Note: Pratt and Fonstad (2009) also analyzed leachate for beryllium, cadmium, chromium, and lead, but those elements could not
be detected. They did not sample the leachate for arsenic; iron is likely to remain chelated, and so would not be free to leach from
the windrow or pile.
a As nitrogen (N).
b Soluble silicon.
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
4.4, Surface Waters and Sediment
As described in Section 2.3.3, the hypothetical site for the assessment includes an on-site lake.
None of the on-site management options directly release chemicals to the lake, but chemicals
could be transported to the lake by one or more processes:
¦ Wet and dry deposition of particles with sorbed chemicals from air (following combustion)
¦ Diffusive exchange of vapor-phase chemicals between the air and surface water
1 Runoff and erosion of chemicals from surface soils into the surface water
¦ Groundwater flow into the lake from the sediment bed
The first three of these processes are modeled using HHRAP equations and default assumptions
for chemicals associated with each of the carcass management options (see Section 5 and
Equation 5-35 in USEPA, 2005a). The HHRAP approach to estimating concentrations of
chemicals in surface water includes three abiotic loss processes: volatilization, hydraulic
turnover or flushing, and sediment burial. Appendix E and USEPA (2005a) summarize the
methods and assumptions for the modeling the surface water and sediment compartments. There
is no net diffusion of vapor-phase chemicals expected from air to surface water. The assessment
assumes vapor-phase chemicals deposited to the lake in precipitation are revolatilized to air.
Chemicals deposited to the soil from air-borne contaminants after combustion-based options may
runoff and erode to surface waters.
The HHRAP SSW models runoff and erosion processes, in addition to the fate of chemicals in
the water column and sediment bed. Appendix E documents the HHRAP SSW Model, and
Appendix F documents the selected parameter values and their sources. HHRAP does not
include equations to simulate recharge from groundwater to surface water. Options to include
this process include: (1) select a groundwater model capable of simulating flux from
groundwater to surface water; (2) develop a simplified estimation method to "bound" the
possible maximum loadings; and (3) exclude this pathway from the quantitative assessment. The
assessment chose the second option to estimate groundwater loading to surface water, with the
chemicals and nutrients carried in the groundwater.
The simplified method to estimate groundwater recharge to surface is applied for the burial
option, leaching from combustion ash, and leaching from the compost windrow and the carcass
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
storage pile. As described in Section 4.3, the groundwater modeling methods include a step that
estimates the total amount (i.e., in milligrams in the first year following carcass management) of
each chemical that reaches the groundwater aquifer. Recharge to the lake is estimated by
assuming the total chemical quantities that reach groundwater, minus the mass drawn by the
drinking water well, eventually reaches the lake. Because it will take time for groundwater to
travel from the source to the lake, the chemicals in groundwater do not necessarily enter the lake
in the first year after carcass management. However, the analysis assumes that all chemicals
discharge from groundwater to the lake occurs within a 12-month period. The amounts reaching
the lake are divided by the volume of the lake to estimate concentrations of each chemical in the
lake water. This approach is conservative (i.e., overestimates chemical concentrations in the
lake) because it assumes the entire plume in a confined groundwater aquifer reaches the lake,
that it all reaches the lake within one a one-year period (might be a year following the start of
leaching), and that all of the chemical flowing into the lake in the year remains in the water
column (i.e., there is no outflow from the lake and chemicals that made it to groundwater do not
precipitate out or sorb to suspended sediments and settle to the bottom). The calculations for this
approach are provided in Appendix I.
The volume of the 40.5 ha (100 ac) lake is calculated by multiplying the surface area (40.5 ha =
404,686 m2) by the average depth (4.38 m, see Section 2.3.3). The resulting volume is 1.8E+06
m3, which equals 1.8E+09 L. As discussed in Section 2.3.3, a smaller (i.e., 4.05 ha or 10 ac) lake
is also included in the assessment to evaluate the effect of the assumed lake size. With its
average depth of 3.02 m, the volume of the smaller lake is 1.2E+05 m3 or 1.2E+08 L.
When combined, the chemical loadings to the 40.5 ha lake from all of the processes listed at the
top of this section are summed to estimate the concentrations in surface water (i.e., in the on-site
lake) shown in Table 4.4.1. No estimate is shown when data are unavailable or no pathways exist
for the chemical of interest. For example, PAHs and dioxins, which are products of combustion,
are not included in the surface water concentration estimates for the composting and burial
options.
In Table 4.4.1, the surface water concentrations for the composting option are presented
separately for leaching from the compost windrow and runoff/erosion following application of
the finished compost to soil. These contributions are presented separately because the sources
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
represent distinct activities and occur at different locations and times on-site. Therefore,
decisions about the management of each compost activity can be made independent of the other
activity.
To evaluate the effect of the assumed lake size on the chemical concentrations in surface water,
Table 4.4.2 compares chemical concentrations in the large and small lakes (40.5 and 4.05 ha,
respectively) for the burial management option. The concentrations in the small lake are
approximately 14.5 times greater than in the large lake. Both lake sizes are large enough to
intersect the entire plume area (i.e., the widest extent of the plume is narrower than the square
root of the lake area).
Table 4.4.1 Estimated Total Concentrations of Chemicals in Surface Water
Concentrations in Surface Water (jig/L), Large Lake (40.5 ha)
Chemical
Species
Storage
Pile
Open
Burning
Air curtain
Burning
Burial
Composting
Windrow
Compost
Application
Total Toxic
Dioxins/furans
na
9.3E-13
3.2E-11
na
na
na
Total PAHs
na
2.0E-04
4.7E-07
na
na
na
Arsenic
na
2.3E-04
4.3E-05
na
na
na
Cadmium
na
1.4E-04
1.1E-04
na
na
1.9E-03
Chromium
na
6.1E-03
2.1E-03
na
na
6.3E-02
Copper
1.6E-10
2.6E-03
1.3E-03
2.5E-09
1.3E-10
2.6E-01
Iron
1.9E-07
1.4E+00
1.0E-01
7.1E-07
3.5E-08
1.3E+02
Lead
na
1.2E-04
4.5E-05
na
na
5.9E-02
Manganese
8.6E-10
5.0E-03
4.9E-02
5.8E-09
2.9E-10
5.6E-01
Nickel
6.9E-10
1.4E-03
2.8E-04
1.4E-09
7.1E-11
6.3E-02
Zinc
6.3E-09
1.1E-02
1.2E-02
6.0E-08
3.0E-09
6.8E-01
Ammonium
2.5E-03
na
na
6.6E-02
3.3E-03
na
Chloride
1.2E-03
na
na
1.5E-02
7.4E-04
na
Phosphorus
4.4E-04
na
na
7.0E-03
3.5E-04
na
Potassium
9.0E-04
na
na
1.2E-02
6.2E-04
na
Sodium
7.6E-04
na
na
1.2E-02
6.0E-04
na
Sulfate
2.7E-03
na
na
4.6E-02
2.3E-03
na
Sulphur
5.7E-04
na
na
1.0E-02
5.0E-04
na
Total Nitrogen
2.2E-02
na
na
2.8E-01
1.4E-02
na
Abbreviations: ha = hectares; na = not assessed; PAHs = polycyclic aromatic hydrocarbons.
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Table 4.4.2. Effect of Lake Size on Estimated Concentrations of Chemicals in Surface
Water - Burial Option
Concentrations in Surface Water (jig/L)
Chemical Species
Burial Option Large Lake (40.5 ha)
Burial Option Small Lake (4.05 ha)
Total Dioxins/furans3
na
na
Total PAHsa
na
na
Copper
2.5E-09
3.7E-08
Iron
7.1E-07
1.0E-05
Manganese
5.9E-09
8.5E-08
Nickel
1.4E-09
2.1E-08
Zinc
6.0E-08
8.7E-07
Ammonium
6.6E-02
9.5E-01
Chloride
1.5E-02
2.2E-01
Phosphorus
7.0E-03
1.0E-01
Potassium
1.2E-02
1.8E-01
Sodium
1.2E-02
1.8E-01
Sulfate
4.6E-02
6.7E-01
Sulphur
1.0E-02
1.5E-01
Total Nitrogen
2.8E-01
4.0E+00
Abbreviations: ha = hectares; na = not assessed; PAHs = polycyclic aromatic hydrocarbons.
a Dioxins, furans, and PAHs are not in carcasses buried or composted; these are produced by pyrolysis in combustion-based
carcass management options. Therefore, they are not assessed for the burial option.
4.5. Bioaccumulation in Fish
Concentrations of chemicals in aquatic animals in the on-site lake allow estimation of human
exposures from consuming fish caught from the lake. Although fish ingestion exposures are
included in the conceptual models for all four on-site carcass management options, the sources of
chemicals to the aquatic food web differ. For the combustion-based options, chemicals reach the
lake through deposition from air, runoff and erosion from soil, and possibly recharge to the lake
from groundwater. For the burial option, chemicals can only reach the lake through groundwater
recharge to the lake. Composting could add chemicals to the lake from (a) surface runoff and
erosion, and (b) the 5% of rainwater that percolates through the windrow to the soil beneath that
is not absorbed by woodchips surrounding the carcasses. All management options include the on-
site storage pile, where liquids can leach downward into the soil toward groundwater, which
might recharge into the lake.
Estimating concentrations of chemicals in the aquatic food web begins with the estimated
concentrations in surface water and sediment (see in Section 4.4). Partitioning of chemicals
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
between the surface water and sediment compartments is modeled with HHRAP (USEPA 2005a)
methods built into the HHRAP SSW Excel model (Appendix E). Two phases are included in
each of two compartments: (la) chemicals dissolved in the water column, (lb) chemicals sorbed
to suspended sediment particles; (2a) chemicals dissolved in the sediment bed pore water, and
(2b) chemicals sorbed to sediment particles.
Concentrations of chemicals in fish are estimated by modeling direct uptake through the gills
from surface water and by ingestion of contaminated prey or foods in sediments and in the water
column. Separate aquatic food web modeling approaches are required for organic and inorganic
chemicals. Bioaccumulation of nonionic organic chemicals is modeled with AQUAWEB, a
steady-state solution model of aquatic bioaccumulation created by Arnot and Gobas (2004) and
available for downloading from Arnot Research & Consulting.14 The biokinetic approach in
AQUAWEB includes rate constants to model chemical uptake through gills and by consumption
in food, possible metabolism (e.g., fish metabolize PAHs), and elimination by organisms in the
food web. In addition to the water and sediment concentrations described above, the model
requires environmental setting inputs including:
¦ average annual water temperature
1 dissolved organic carbon content
¦ particulate organic carbon content
¦ total suspended solids
¦ sediment organic carbon content
AQUAWEB requires assumptions about the species composition of the aquatic community and,
for each species and size or age class of animal included in a food web, default values for the
diet, body size, fraction lipid, and fraction of pore water ventilated. This assessment uses values
developed to represent small lakes in Minnesota (e.g., 40.5 ha, see Appendix J).
AQUAWEB is not designed to model the behavior of inorganic chemicals, including metals, in
aquatic food webs. For metals included in the assessment (see Section 2.4.1), bioaccumulation to
fish is estimated using previously-published empirical bioaccumulation factors (BAFs) (see
Appendix J). The BAF approach does not include explicit accumulation through algae,
14 Further information and model download are available at: http://www.arnotresearch.eom/index.html# !/page AQUAWEB.
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
zooplankton, and planktivorous fish. Those intermediate transfers through the food web are
implicit in field- or microcosm-measured bioaccumulation (i.e., measured fish tissue
concentrations divided by dissolved concentrations in water). This assessment assumes livestock
carcasses and combustion fuels contain natural concentrations of metals (e.g., iron, copper) that
are either in organic compounds or as oxides or metallic ions depending on the carcass
management option.
Table 4.5.1 shows the fish tissue concentrations estimated with the methods described above.
These concentrations lead to estimates of chemical exposure from fishing by the farm residents.
1.1,Terrestrial Plants a restock
The concentration of chemicals in plants and livestock grown at the hypothetical farm are
modeled to estimate human exposure for those consuming home-grown food products.
Concentrations of chemicals in farm-grown plants and livestock are estimated with an existing
Excel-based computer model called the Multimedia Ingestion Risk Calculator (MIRC), which
uses equations and default assumptions from HHRAP (USEPA 2005a). For documentation of
MIRC, including input parameter values, see Appendix K. Detailed documentation of the
relevant HHRAP methods and default assumptions is available in USEPA (2005a).
MIRC was developed for USEPA's Office of Air Quality Planning and Standards (OAQPS) to
provide screening-level estimates of multimedia chemical exposures and risks associated with
subsistence and recreational farmers in the vicinity of a source of chemical emissions to air and
those associated with subsistence or sport anglers fishing from a contaminated lake. MIRC
complies with USEPA guidelines for exposure and risk assessment, including the Human Health
Risk Assessment Protocol (USEPA 2005a), the Agency's 2005 Guidelines for Carcinogen Risk
Assessment (Cancer Guidelines, USEPA 2005b), Guidance on Selecting Age Groups for
Monitoring and Assessing Childhood Exposures to Environmental Contaminants (USEPA
2005c), Supplemental Guidance for Assessing Susceptibility from Early-Life Exposure to
Carcinogens (Supplemental Guidance, USEPA 2005d), along with implementation memoranda
(USEPA 2005e, 2006), and the Agency's Child-Specific Exposure Factors Handbook (USEPA
2008). In addition, MIRC itself is a component of USEPA's overall approach to assessing
residual (i.e., post-regulatory) risk for sources of hazardous air pollutants (HAPs) regulated
under the CAA, an approach that has been reviewed by USEPA's Science Advisory Board.
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Table 4.5.1. Estimated Chemical Concentrations in Fish from the On-site Lake
Estimated Concentration in Trophic Level 3 and 4 Fish (mg/kg)a
Chemical
Species
Storage Pile
Open Burning
Air curtain
Burning
Burial
Compost Windrow
Compost
Application
T3
T4
T3
T4
T3
T4
T3
T4
T3
T4
T3
T4
Total
Dioxins/furans
na
na
6.3E-12
4.1E-12
1.0E-09
5.7E-10
na
na
na
na
na
na
Total PAHs
na
na
6.2E-05
8.3E-05
1.3E-07
1.8E-07
na
na
na
na
na
na
Arsenic
na
na
3.9E-06
3.9E-06
7.3E-07
7.3E-07
na
na
na
na
na
na
Cadmium
na
na
5.8E-06
5.8E-06
4.6E-06
4.6E-06
na
na
na
na
7.5E-05
7.5E-05
Chromium
na
na
1.4E-03
1.4E-03
4.7E-04
4.7E-04
na
na
na
na
1.4E-02
1.4E-02
Copper
2.3E-11
2.3E-11
3.9E-04
3.9E-04
1.9E-04
1.9E-04
3.8E-10
3.8E-10
1.9E-11
1.9E-11
3.9E-02
3.9E-02
Iron
2.3E-08
2.3E-08
1.7E-01
1.7E-01
1.2E-02
1.2E-02
8.5E-08
8.5E-08
4.2E-09
4.2E-09
1.5E+01
1.5E+01
Lead
na
na
2.4E-06
2.4E-06
9.0E-07
9.0E-07
na
na
na
na
1.2E-03
1.2E-03
Manganese
2.6E-11
2.6E-11
1.5E-04
1.5E-04
1.5E-03
1.5E-03
1.8E-10
1.8E-10
8.8E-12
8.8E-12
1.7E-02
1.7E-02
Nickel
1.4E-11
1.4E-11
2.9E-05
2.9E-05
5.7E-06
5.7E-06
2.8E-11
2.8E-11
1.4E-12
1.4E-12
1.3E-03
1.3E-03
Zinc
1.5E-09
1.5E-09
2.5E-03
2.5E-03
2.7E-03
2.7E-03
1.4E-08
1.4E-08
6.9E-10
6.9E-10
1.6E-01
1.6E-01
Abbreviations: na = not assessed; PAHs = polycyclic aromatic hydrocarbons.
a Trophic level 4 (T4): top predatory fish in water column (e.g., walleye, northern pike); Trophic level 3 (T3): "pan" fish (e.g., bluegill, yellow perch).
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MIRC assesses human exposure via ingestion pathways, including drinking water consumption,
incidental soil ingestion, fish ingestion, and ingestion of ten types of agricultural products:
exposed fruits, protected fruits, exposed vegetables, protected vegetables, root vegetables, beef,
total dairy, pork, poultry, and eggs. For fruits and vegetables, the terms "exposed" and
"protected" refer to whether the edible portion of the plant is exposed to the atmosphere.
The inputs to MIRC include chemical concentration and deposition rates:
1 Total concentration of the chemical in the air
1 Fraction of the chemical in the air in the vapor-phase
¦ Wet and dry deposition rates for particle-phase chemical
¦ Concentration of the chemical in drinking water
¦ Concentration of the chemical in soil
¦ Concentration of the chemical in upper trophic-level fish
Methods for estimating each of these inputs are described in previous sections.
Inputs to MIRC also include assumptions about the potentially exposed adults and children, the
exposure scenario (e.g., which foods are eaten and at what rate), and chemical-specific
parameters values. Built into MIRC are exposure factors for six age groups to allow use of age-
group-specific body weights, ingestion rates, food preferences, and susceptibility to toxic effects.
For most exposure factors and age-groups, MIRC can use mean or 50th, 90th, 95th, and 99th
percentile values (only one value per factor or parameter). Mean exposure factor values are used
in this assessment, because means are additive and multiplicative and higher percentiles are
much less certain that mean values. Moreover, this assessment estimates relative risks among
carcass management options, not absolute risks for most exposed individuals. Most default
exposure factor values in MIRC are from USEPA's Exposure Factors Handbook (EFH; USEPA
2011) and its Child-Specific Exposure Factors Handbook (CSEFH; USEPA 2008). For the
specific exposure factor values in this assessment see Appendix K.
MIRC requires chemical-specific parameter values as inputs including empirical partitioning and
biotransfer factors (e.g., soil-water partition coefficients, soil-to-plant biotransfer factors). Values
for most of the parameters in MIRC are from a chemical database developed by USEPA for use
with HHRAP. For parameter values in this assessment and their sources, see Appendix K.
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1.1.1. Terrestrial Plants
With the HHRAP methods built into MIRC, produce (vegetables and fruits) can be contaminated
directly by deposition of airborne chemicals to foliage and fruits or indirectly by uptake of
chemicals in soil. Given those two pathways, produce is divided into two main groups:
aboveground and belowground. Aboveground produce is divided into fruits and vegetables. As
described above, those groups are further subdivided into "exposed" and "protected" depending
on whether the edible portion of the plant is exposed to the atmosphere or is protected by a husk,
hull, or other outer covering. These pathways are summarized in Table 4.6.1.
The methods used to estimate exposure concentrations in produce for human consumption are
also used to estimate concentrations in forage, silage, and grain grown on-site for livestock feed.
Concentration estimates provided by HHRAP include wet-weight (ww) concentrations (mg/kg)
of each chemical in exposed vegetables, protected vegetables, exposed fruits, protected fruits,
and roots. Dry-weight (dw) concentration estimates are provided as well for above-ground
produce.
Table 4.6.1. Chemical Transfer Pathways for Produce
Farm Food Media
Chemical Transfer Pathways
Aboveground Produce
¦ Exposed fruits and vegetables
¦ Direct deposition from air of particle-bound
chemical (generally washed off)
¦ Air-to-plant transfer of vapor phase chemical
¦ Root uptake from soil
¦ Protected fruits and vegetables
¦ Root uptake from soil
(e.g., grains, peas)
Belowground Produce
¦ Root vegetables (e.g., onions,
potatoes)
¦ Root uptake from soil
MIRC provides concentration estimates for each chemical and each food source. These results
lead to estimates of the combined ingestion exposure from eating produce (see Section 5.3.2).
1.1.2. Livestock
Concentrations of chemicals are estimated in livestock products, including beef and dairy
products, pork, and poultry and eggs. Note that the HHRAP methods used to model livestock did
not include inhalation of vapor-phase and particulate contaminants by livestock or use of well
water for watering livestock.
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Chemical concentrations in animal products are estimated based on the amount of chemical
consumed by each animal group through each type of feed and incidental ingestion of soil for
ground-foraging animals. Table 4.6.2 summarizes the pathways by which chemicals are
transferred to the farm-raised animal food products. Beef and dairy cattle consume three plant
feeds (i.e., forage, silage, and grain), while pigs consume only silage and grain, and chickens
consume only grain. These feed products are grown on-site and might contain chemicals.
Incidental ingestion of chemicals in soils by livestock during grazing or consumption of feed
placed on the ground is estimated for the combustion-based management options using empirical
soil ingestion rates and a soil bioavailability factor for livestock. The default value for that factor,
which is used for the exposure assessment, for all chemicals is 1.0 (i.e., the chemical in soil is
assumed to be 100% bioavailable to the animal).
HHRAP calculates chemical ingestion by livestock so that chemical concentrations in human
food products can be estimated, not to estimate risks to the livestock animals. The relevant
estimates provided by HHRAP are mg chemical per kg fresh or ww product. Concentrations are
estimated separately for beef, total dairy, pork, poultry, and eggs. These results, for each
management option and chemical, are used to estimate ingestion exposure from food. Those
estimates are presented in Section 5.
Table 4.6.2. Chemical Transfer Pathways for Livestock
Farm Food Media Chemical Transfer Pathways
Animal Products
¦ Beef and total dairy (including
¦ Ingestion of forage, silage, and grain3
milk)
¦ Incidental soil ingestion
¦ Pork
¦ Ingestion of silage and grain3
¦ Incidental soil ingestion
¦ Poultry and eggs
¦ Ingestion of grain3
¦ Incidental soil ingestion
a Chemical concentrations in forage, silage, and grain are estimated via intermediate calculations analogous to those used for
aboveground produce.
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5. Exposure Estimation for Chemicals
This section describes how chemical concentrations in the environment and in food are used to
estimate exposures of adults and children at the farm. In Section 7, these estimates are compared
to toxicity benchmarks to normalize the exposures to the inherent toxicity of the chemicals to
allow comparison of the livestock carcass management options. This section also uses chemical
concentrations in the environment to discuss exposures to livestock and wildlife.
For humans, adults and children can be exposed via inhalation and ingestion. Inhalation exposure
is included only in the combustion-based management options and only for the duration of the
burn. Exposure concentrations (i.e., mg chemical/m3 air) are estimated as event-average
concentrations for the 48-hr combustion events. Ingestion exposure is evaluated for a one-year
period starting with the beginning of the carcass management. Sources of ingestion exposure
include drinking water; fish caught in the on-site lake; and home-grown fruits, vegetables, and
livestock products. For both inhalation and ingestion, exposure factors (e.g., body weight,
ingestion rates) used in the assessment were mean values obtained from the most recent version
of USEPA's Exposure Factors Handbook (USEPA 2011), its Child-specific Exposure Factors
Handbook (USEPA 2008), and its Child-Specific Exposure Scenarios Examples (USEPA
2014b).
Section 5.1 summarizes the exposure pathways included in the chemical exposure assessment.
Section 5.2 describes the approach to characterizing the human receptors for the purpose of
ranking management options by potential exposures. Section 5.3 presents the chemical exposure
estimates for each of the management options included in the quantitative human exposure
assessment. Section 5.4 summarizes the livestock and environmental exposure estimates
expressed as environmental concentrations.
5.1, Sum man of Chemical Exposure Pathway tm Humans
Table 5.1.1 summarizes pathways of human exposure to chemicals included in the exposure
assessment. Pathways within the scope of the assessment were first defined in Section 3 of this
report. Exposures are estimated for some, but not all of those pathways. Pathways with estimated
exposures are indicated with bold type and footnote "a" in Table 5.1.1.
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Pathways for which exposures are not estimated are indicated by footnotes "b" and "c" in Table
5.1.1. Footnote "b" denotes exposure pathways assumed to be negligible reasons discussed
below.
Footnote "c" denotes exposures that are not estimated because of applicable environmental and
worker safety regulations and guidelines. For example, the assumed use of PPE, including
gloves, by workers would limit incidental ingestion and direct dermal contact with carcasses,
carcass fluids, and media contaminated by spills, or other contact with carcass materials. In
addition, exposure pathways for the off-site management options are not estimated because
releases to the environment from those options are limited by pollution control systems that are
assumed to operate within permitted levels (see Section 2.1).
Exposure pathways indicated by footnote "b" in Table 5.1.1 include the pathways not quantified
for reasons described below. The reasons and specific pathways are listed for each exposure
source row in the Table 5.1.1:
¦ Inhalation - As discussed in Sections 3.4 and 3.5.2, gases such as ammonia and hydrogen
sulfide diffuse passively from windrows and closed burial trenches. The odors often
stimulate people to rapidly leave areas where these gases are diffusing, creating a
behaviorally-induced reduction in exposure. The relatively slow rate of release, high dilution
by the atmosphere, and limited exposure periods (i.e., minutes to hours) preclude these gases
from reaching concentrations that might be hazardous to humans. Trucks that haul carcasses
from the temporary storage location to the carcass management site also release chemicals
into the air. Inhalation exposures from transportation of carcasses are negligible because of
atmospheric dilution and very short periods for passing vehicles. These reasons for not
evaluating inhalation exposures apply to five pathways in Table 5.1.1:
• Carcass handling, exposure pathway number 1
• Temporary carcass storage, exposure pathway number 1
• Carcass transportation, exposure pathway number 1
• Burial, exposure pathway number 1
• Composting, exposure pathway number 1
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Pathways with inhalation of aerosolized well water by humans (e.g., while showering) are
not quantified because those pathways are assumed to be insignificant compared with
ingestion of drinking water. Four pathways listed in Table 5.1.1 are not assessed for
inhalation of aerosolized well water:
• Temporary carcass storage, exposure pathway number 2
• Open burning and air-curtain burning, exposure pathway number 2
• Burial, exposure pathway number 2
• Composting, exposure pathway number 2
¦ Incidental ingestion - Hand-to-mouth contact followed by ingestion could occur whenever
workers and farm residents touch carcasses, leachate, or contaminated soil, and subsequently
touch their mouths. For workers, this risk is avoided by the assumed appropriate use (and
cleaning and storage) of gloves and other PPE. Farm residents are unlikely to be near the
combustion site, and are likely to appropriately wash hands and bathe, which effectively
limits their risk of ingestion exposure. Children engaging in geophagy are unlikely to access
the work site, and are unlikely to directly consume contaminated soil. In all cases, the
frequency and duration of exposure is likely to be very short. Consequently, accidental
ingestion of chemicals associated with carcass management options is considered an
incidental exposure posing negligible risk for workers and all types of farm residents. A
separate consideration is that the soil exposure analysis assumes chemicals deposited from
the air are instantaneously mixed and diluted with surface soil to a depth of 2 cm. For those
reasons, three chemical exposure pathways in Table 5.1.1 are not quantified:
• Carcass handling, exposure pathway number 2
• Carcass transportation, exposure pathway number 3
• Open burning and air-curtain burning, exposure pathway 3
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Table 5.1.1. Human Exposure Pathways for Livestock Carcass Management - Chemicals
Carcass Transportation and Handling
Carcass Management Options
Exposure
Source
Carcass Handling
Temporary
Carcass Storage
Carcass
Transportation
Open Burning and
Air curtain
Burning
Burial
Composting
Inhalation
1) Airb
1) Airb
2) Leachate —> GW
—> In-home Aerosol0
1) Airb
1) Air3
2) Ash —> GW —>
In-home Aerosol13
1) Airb
2) Leachate —> GW
—> In-home Aerosol13
1) Airb
2) Compost —> GW
—> In-home Aerosol13
Incidental
Ingestion
2) Hand-to-mouth
ingestion13'0
—
2) Accident —> soil1,0
3) Air —> soilb
—
—
Dermal
3) Direct dermal
contact0
—
3) Accident —> soil0
—
—
—
Fish Ingestion
—
3) Leachate —> GW
—> SW —> Fish3
—
4) Air —> SW —>
Fish3
5) Air —> soil —>
SW -> Fish3
6) Ash —> GW —>
SW -> Fish3
3) Leachate —> GW
—> SW —> Fish3
3) Compost —> soil
—> SW —> Fish3
4) Compost —> GW
—> SW —> Fish3
Ground-water
Ingestion
—
4) Leachate —>
GW
—
7) Ash -> GW3
4) Leachate —>
GW3
5) Compost —> GWa
Food Produced
on the Farm ~
Ingestion
—
5) Air —>
Plants/livestock13
6) Leachate —> GW
—> Livestock13
—
8) Air ->
Plants/livestock3
9) Air -> Soil ->
Plants/ Livestock3
10) Ash —> GW —>
Livestock13
5) Air —> Plants/
Livestock13
6) Leacliate —> GW
—> Livestock13
6) Compost —> Soil
—> Plants/
Livestock3
7) Air —> Plants/
Livestock13
8) Compost —> soil
—> GW —>
Livestock13
Abbreviations: "—" = no exposure pathways; SW = surface water; GW = groundwater.
Exposure pathways shown in bold were included in the quantitative exposure assessment. Pathways were not quantitatively assessed for the following reasons:
a Quantitative methods were available for exposure assessment; Results are presented in Section 6.3.
b Potential exposures were assumed to be negligible based on source conditions or chemical properties.
c Environmental releases or exposures were assumed to be adequately controlled by existing pollution control regulations or use of personal protective equipment.
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* Ingestion of food produced on the farm - Airborne chemicals might be taken up from the
air or settle on plant surfaces that are later consumed. Volatile gases (e.g., ammonia)
generated by carcass decomposition are given off from the storage pile and seep upward
through cover materials, including soil (burial option) or wood chips (composting option). As
discussed above and in Sections 3.4 and 3.5.2, available data (e.g., by Glanville et al. 2006)
indicate concentrations of gases are unlikely to be hazardous for the carcass management
scenarios included in this assessment and report (Table 5.1.1):
• Temporary carcass storage, exposure pathway number 5
• Burial, exposure pathway number 5
• Composting, exposure pathway number 6
The conceptual model for the food chain associated with the farm's productivity includes
pathways with livestock receiving well water containing chemicals leached from combustion
ash, buried carcasses, temporary carcass storage piles, or compost windrows. Only lipophilic
chemicals are likely to accumulate in livestock, and as discussed in Section 5.3 below, those
do not reach the groundwater well at measureable concentrations. For those reasons, four
pathways in Table 5.1.1 are not assessed:
• Temporary carcass storage, exposure pathway number 6
• Open burning and air-curtain burning, exposure pathway numberlO
• Burial, exposure pathway number 6
• Composting, exposure pathway number 7
5.2, Characterization of Exposed Individuals
This section discusses who the assessment assumes is exposed to chemical, as well as
characteristics about them (e.g., age) and their behavior (e.g., location) that affect estimated
levels of exposure. Specifically, Sections 5.2.1 through 5.2.4 discuss four parameters:
1 Description of exposed persons (e.g., infants, adults)
¦ Durations of exposures
¦ Distance between management option source and human receptors
¦ Selection of human exposure factor values
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1.1.1. Description of Exposed Persons
Exposure is estimated for three types of farm residents: infants who consume drinking water in
their formula, young children (age 1-2 years old), and adults who live on the farm near the
carcass management unit for at least one year after carcass management. A young child (e.g., age
1 to 2 years) consumes more food per unit body weight on a daily basis than older children and
adults. For the young child, exposure is calculated from estimated concentrations of chemicals a
limited diet of foods produced on the farm, using assumptions about a small body weight, and
higher metabolic rates (ingestion and inhalation rates). For the adult, exposure is calculated from
estimated concentrations of chemicals in the drinking water and food items using mean values
for various exposure factors (e.g., body weight, ingestion rates for different foods and water,
inhalation rates).
1.1.2. Exposure Durations
The assessment includes two exposure routes and durations: inhalation over 48 hours and
ingestion (i.e., of drinking water, home-grown food products, and fish) over one year. Although
the dermal exposure route is included in Table 5.1.1, all dermal exposure pathways are negligible
because of the assumed use of gloves and other PPE.
Inhalation exposures are assessed only for the combustion-based management options. As
described in Section 3, Tables 3.2.1 and 3.3.1, open burning and air-curtain burning are assumed
to continue for 48 hrs. Exposure concentrations in mg chemical/m3 air are estimated as event-
average concentrations. That means the assessment uses average chemical concentration present
in the air during that 48 hr period (at the location of maximum air concentrations).
Ingestion exposures are evaluated for a one-year period starting with the beginning of the carcass
management actions. The one-year exposure periods for the various ingestion sources do not
necessarily coincide with one another. For example, drinking water exposure begins when the
chemicals in groundwater reach the well. Ingestion of home-grown foods begins for the
combustion-based options after chemicals are deposited from air to soil and plants, and for the
composting option after finished compost is applied as a soil amendment.
All ingestion exposures are assumed to be constant and uniform throughout the one-year periods.
Chemical concentrations in drinking water, home-grown produce, and fish based on the total
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chemical released during the first year to an environmental medium after accounting for
chemical movement to other environmental media (e.g., from surface soil to the lake) are
assumed to represent the average daily exposure concentrations for one year, as described in
Section 4. The exposure assumptions, such as the availability and consumption of home-grown
food products, are assumed to be consistent throughout the year (i.e., data for seasonal changes
not available).
Exposures to chemicals in drinking water and fish following leakage from the storage pile are the
same for all seven carcass management options. They are evaluated separately from the carcass
management options, which also allows the exposures from handling activities to be compared
with exposures from carcass disposal.
1,1,3, Human Exposure Factor Values
This assessment uses mean life-stage-specific exposure factor values that are included in MIRC.
Those values are from the most recent version of USEPA's Exposure Factors Handbook
(USEPA 2011), its Child-specific Exposure Factors Handbook (USEPA 2008), and its Child-
Specific Exposure Scenarios Examples (USEPA 2014b). These handbooks include a thorough
review of relevant original data and list the USEPA-recommended values for use in exposure
assessments. The handbooks provide mean, median, and percentile (e.g., 75th, 9099th
percentiles) values to allow the user to determine the degree of conservatism appropriate for each
factor as used in their particular type of exposure assessment (e.g., screening, ranking, refined).
The purpose of this comparative exposure assessment is to rank the management options by their
exposure potential relative to each other, not to estimate possible real-world maximum individual
or population exposures or risks for any of the options. As a consequence, the most appropriate
value to select for each exposure factor is the mean value, not an upper percentile value as often
is selected for screening-level risk assessments to represent most exposed individuals. Mean
values are preferred for exposure factor values used in the ranking of carcass management
options for several reasons:
¦ Mean values are the most robust (i.e., have the most narrow confidence limits) of the
statistical descriptors of parameter distributions. The more extreme values (i.e., values near
the "tails") in a natural distribution of parameter values, such as a 95th or 99th percentile
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
value, are more uncertain (i.e., and have much wider confidence limits). Upper percentile
values (i.e., upper tail of a distribution) can be highly skewed by outlier values in the data
set.
¦ The expected value, or mean, of the sum of two random variables is the sum of the means
(additive law of expectation).
¦ The mean of the product of two parameters (with any type of distribution of values) is the
product of the mean values if (and only if) the two parameters are not correlated with one
another.
¦ If the variables are correlated (e.g., body weight positively correlates with daily quantities of
food ingested), then the product of the mean values for each parameter will likely be smaller
than the mean of the product of the values (e.g., the same individual). To avoid this error,
original data on food ingestion rates for each individual should be expressed as kg food
ingested per kg of body weight per day. The mean of that distribution should be a more
accurate measure than taking the mean of food ingestion rates (kg/day) across all adults and
dividing by the mean body weight of all adults (in kg).
¦ Percentiles for random variables generally are not additive or multiplicative whether the
variables are correlated to some degree or not. Instead, reasonably accurate estimates of a
percentile (e.g., 90th percentile) for the sum, product, or ratio of two (or more) random
variables generally requires a Monte Carlo simulation in which the distribution of each
variable and its correlation with the others are well defined. For example, multiplication of
upper percentile values for two independent parameters (e.g., 95th percentile for exposure
concentration in water in mg/L multiplied by the 95th percentile water ingestion rate in L/kg
body weight/day) yields a much more conservative (i.e., higher) percentile value (e.g.,
99.9th) than the original percentile value (e.g., 95th). Moreover, using the percentile requires
knowledge of the shape of the original distributions and their variances even if the two
parameters are completely uncorrected.
For the purpose of ranking the livestock carcass management options based on their relative
exposure potential, mean values for adult and child body weight, food and water ingestion rates,
and inhalation rates are used (see Table 5.2.1) as documented in Appendix K. For infants,
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exposures are considered from well water used to mix with formula, with both mean and high-
end exposure factor values as listed below.
Table 5.2.1. Typical and High-end Exposure Factor Values For Infant Water Consumption
Parameter
Typical or Mean
Scenario mL/kg d
High end Scenario
mL/kg d (95th %)
Rationale or Source
Intake by infant <
1 month
137
238
Table 3-1 in USEPA (2011) Exposure
Factors Handbook, Consumers-Only
drinking water
Intake by infant:
1-3 months
119
285
Table 3-1 in USEPA (2011) Exposure
Factors Handbook, Consumers-Only
6-12 months
53
129
drinking water
Abbreviations: d = day; USEPA = U.S. Environmental Protection Agency.
5.3.Exposure Estimation
This section describes the methods used to estimate chemical exposures for each carcass
management option. Separate estimation methods are used for human inhalation (Section 5.3.1)
and ingestion (Section 5.3.2) exposures.
1.1.1. Inhalation
Inhalation exposures are calculated for adult farm residents at a location of maximum
concentrations of the chemicals in air as estimated by AERMOD on a date for which
meteorological conditions resulted in the highest 48-hr average concentration. For combustion-
based management options, this assessment uses only the 48-hr average exposure from
chemicals released into the air (see Section 5.2.2). These average inhalation exposures are then
compared with acute toxicity reference concentrations (RfCs) if available (see Section 7).
Separate exposure estimates are not made for adults and children because evaluation of
inhalation exposures occurs on an air-concentration basis and not an exposure-dose basis.
The conceptual model includes inhalation of aerosolized chemicals from home uses of well
water (specifically showering as the worst-case home-use scenario). However, given the low
ranking ratios associated with ingestion of drinking water, this inhalation exposure pathway is
considered negligible, and is not estimated.
Combustion products from open burning and air-curtain burning include two groups of
compounds (PAHs and dioxins/furans) with similar chemical structures in each group and toxic
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health effects. Although similar, the individual compounds in each group do differ in their toxic
potency. Previous researchers developed relative potency factors (for PAHs, see Appendix A) or
toxicity equivalency factors (for dioxins and furans, see Appendix B) to express the toxicity of
each compound relative to an index compound within the group. The compound-specific
concentrations are multiplied by these factors before totaling the exposure concentration in air
for the chemical groups. This assessment evaluates PAHs and dioxins/furans as a whole by
totaling the maximum event-average concentrations for each chemical in these groups. The total
dioxin/furan concentration in air is reported as 2,3,7,8-TCDD equivalents, and the total PAH
concentration in air is reported relative to the cancer potency value of benzo(a)pyrene (BaP).
This assessment assumes the location of the maximum concentration in air is the same for all of
the chemicals.
Table 5.3.1 presents concentrations of chemicals in air found during open burning and air-curtain
burning. Concentration differences can be explained by the different emission factors for carcass
combustion and the chemical content and emission factors for the fuels. For example,
concentrations of metals may be higher with open burning than air-curtain burning because of
the coal used as a fuel in the pyre. Concentrations from air-curtain burning would be lower if a
2:1 wood:carcass ratio were used instead of the 4:1 ratio assumed here.
1.1.2. Ingestion Media
Ingestion media in the exposure assessment include drinking water, soil, fish caught locally in
the lake, five types of home-grown produce, and five types of home-raised animals or animal
products. Equations and assumptions to estimate those exposures are based on relevant portions
of HHRAP as implemented in MIRC.
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Table 5.3.1. Inhalation Exposure Concentrations Open Burning and Air-curtain Burning
Chemical Species
Maximum Event average Air Concentration (jig/m3)
Open Burning
Air curtain Burning
Dioxins/furans
4.2E-10
7.4E-08
Total PAHs
6.8E-02
2.6E-04
Arsenic
7.7E-04
2.9E-04
Cadmium
1.4E-03
2.0E-03
Chromium
1.2E-02
9.3E-03
Copper
9.5E-03
1.0E-02
Iron
3.1E+00
5.7E-01
Lead
1.3E-02
9.3E-03
Manganese
2.9E-02
7.0E-01
Nickel
1.1E-02
4.3E-03
Zinc
9.9E-02
1.7E-01
Abbreviations: PAH = polycyclic aromatic hydrocarbon.
Average daily ingested doses (ADDs in mg/kg/day) are estimated using generic Equation 5.1:
ADDing = (Cprod ' IR * FC * ED/BW * AT) * (EF /365 days) Eqn. 5.1
where:
ADDmg = Average daily ingestion dose (mg/kg/day)
Cprod = Concentration of chemical in ingestion medium (mg/kg or mg/L)
IR = Age-group specific ingestion rate for ingestion medium
(kg/day or L/day)
FC = Fraction of food type harvested from the contaminated farm area
ED = Exposure duration (yr)
BW = Age-group-specific body weight (kg)
AT = Averaging time (yr)
EF = Annual exposure frequency for age group (days)
A version15 of this equation is used in MIRC for each ingestion medium to calculate average
daily doses (ADDs) for each receptor age group (i.e., adult or young child) and chemical.
The above equation accounts for the chemical concentration in each ingested food, the quantity
of food brought into the home for consumption, how much of that food is consumed per year, the
amount of the food obtained from the affected area, and the consumer's body weight (USEPA
15 Variations of the equation include units, conversion factors, cooking loss factors, or other adjustments for the specific ingestion
source.
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
2011). MIRC includes factors for food preparation and cooking losses account for the amount of
a food product as brought into the home that is not ingested due to loss during preparation,
cooking, or post-cooking (see Appendix K). Two additional exposure media are included to
estimate the total daily dose of each chemical ingested: drinking water and soil (from incidental
ingestion). In MIRC, ADDs are calculated separately for each chemical, ingestion medium, and
receptor age group. All the ADDs for a given carcass management option are then summed for
each combination of receptor age group and chemical.
For fish ingestion, the assessment assumes that farm residents catch and consume both water-
column game fish (e.g., walleye, northern pike) and pan fish (e.g., yellow perch, bluegill). The
fish ingestion rates are mean values for the general population developed by USEPA's Office of
Air Quality Planning and Standards OAQPS for use in multimedia risk assessments in support of
USEPA's Risk and Technology Review program. As described in Appendix K, OAQPS
estimated the values of 7 g/person/day for adults and 1.4 g/person/day for children age 1 to 2
years (Table K.15) from data presented in USEPA's (2002) EstimatedVox capita Fish
Consumption in the United States and the Agency's (2008) Child-Specific Exposure Factors
Handbook. Subsistence fish ingestion rates are not used because the farm residents also rely on
home-grown plants and livestock for food.
All ingestion ADDs are calculated assuming one year of exposure to the chemicals (exposure
duration [ED] of 1 yr), exposure that every day during the year (i.e., exposure frequency of 365
days/yr), and that all of the food or drinking water ingested is from potentially contaminated food
and drinking water obtained on site (i.e., the fraction from the contaminated area is 1.0). The
averaging time in the equation above (AT of 1 yr) is the period of time over which the average
daily chemical exposure is averaged. Only the first year following management of the carcasses
on site is assessed, because that is the year in which chemical concentrations will be highest in
environmental media. Chemical concentrations in subsequent years will be lower as various loss
processes (e.g., diffusion, dispersion, degradation, movement of chemicals to other
environmental media) continue over time. Thus, exposures will continue, but decrease at a rate
that is difficult to calculate across carcass management options.
For non-cancer effects, the first year of ingestion exposure is normalized to toxicity reference
values—subchronic toxicity reference values (TRVs) if available, chronic TRVs if subchronic
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
values are not available. Strictly speaking, a subchronic exposure for humans is seven years long;
however, this assessment is not calculating risks, it is ranking carcass management options after
chemical exposures are normalized to inherent toxicity to the extent feasible.
For cancer, which can occur after exposure and for which USEPA assumes a 70-yr exposure
duration in calculating carcinogenic potency, a 1-yr exposure duration is too short to
appropriately represent a risk of developing cancer over a lifetime using cancer potency factors.
Instead, to identify a risk-specific dose, the 1-yr exposure estimate is divided by 70 yrs.
For each carcass management option, chemical-specific ingestion exposures, expressed as
ADDs, for each age group (i.e., adult and child aged 1-2), are summed across ingested drinking
water, fish, five types of home-grown produce, and five types of home-raised animals or animal
products. Total ADD for a particular age groups (ADDfy)) is estimated as the sum of a given
chemical ingested from all pathways from which the chemical could be consumed. The ADDs
for PAHs and dioxins/furans associated with combustion options are totaled using the relative
potency factor (RPFs) and toxicity equivalency factors (TEQs), respectively, described in the
previous section.
Ingestion exposure estimates (i.e., ADDs) for adults and young children associated with each
management option are presented in Tables 5.3.2 through 5.3.14. These tables include ADDs for
each food ingested, drinking water, and incidental soil ingestion, which are added to calculate the
total ingestion exposure for each chemical. The tables list "na" if the exposure is not assessed.
This situation arises when either: (1) the chemical was not released by the particular management
option (e.g., dioxins and PAHs are created by combustion and are not present in carcasses
initially); (2) data are not available to estimate exposure to a particular chemical; or (3) there is
no exposure pathway within that particular scenario or for that particular chemical. One example
of the last situation is fish ingestion by infants <1 year of age is not estimated, because that age
group does not consume fish (assume formula feeding for first year after birth). Farm produce
exposure is not estimated for the burial option, and the drinking water exposure is not estimated
for the composting option. The pathways evaluated for each option are discussed in Sections 3.1
through 3.5.
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
Exposure estimates for the four on-site management options do not include exposure pathways
associated with the temporary carcass storage pile or with transportation on- or off-site. Each of
those two possible sources of exposure are assumed to be equal across all management options
(see Tables 5.3.2 and 5.3.3). Presenting possible exposures from the storage pile separately
allows them to be compared with other exposures associated with the management options. In
addition, exposures for the composting option are presented separately for pathways associated
with leakage from the windrow to the ground below (Tables 5.3.10 and 5.3.11) and application
of the finished compost to agricultural land on site (Tables 5.3.12 and 5.3.13). Table 5.3.14
presents ingestion estimates for each of the on-site management options for infants who consume
powdered formula reconstituted with well water. Breast milk ingestion is an important pathway
for nursing infants for lipophilic chemicals, which are limited to PAHs and dioxins and furans
for the current assessment. However, this is an assessment of relative exposures across carcass
management options, not of maximum individual risks (e.g., to an infant who might be more
exposed to some chemicals in breast milk and less exposed to other chemicals). Breast milk
ingestion and nursing infants, therefore, are not included in the conceptual models resulting from
problem formulation.
Ingestion exposures estimated for adults and young children generally are within an order of
magnitude. Estimated ingestion exposures for children are greater than those for adults, because
children ingest more food and water per unit body weight than do adults. Many of the estimated
ADDs are very small, many orders of magnitude below any toxicity reference value. All
estimates are included in Tables 5.3.2 through 5.3.14, however, to show which chemical and
ingestion source combinations constitute a complete pathway.
The estimates are based on the hypothetical farm setting, a standardized set of environmental
conditions (e.g., meteorology), methods with considerable uncertainties, and assumptions that
are not necessarily representative of site-specific carcass management efforts. For these reasons,
this exposure assessment should not be regarded as providing estimates of actual exposures
likely from the management options. Despite their inherent uncertainty, the exposure estimates
are useful for comparing the management options relative to one another, in terms of the number
of potential pathways and relative exposure levels, with each chemical exposure normalized to
levels that can cause adverse effects on human and environmental health.
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
Table 5.3.2. Ingestion Exposure Estimates for Temporary Carcass Storage - Adults
Chemical Species
Ingestion Average Daily Dose (mg/kg d)
Drinking Water
Farm Produce
Fish
Total Ingestion
Total Dioxins/furans
na
na
na
na
Total PAHs
na
na
na
na
Arsenic
na
na
na
na
Cadmium
na
na
na
na
Chromium
na
na
na
na
Copper
5.0E-14
na
3.0E-12
3.1E-12
Iron
6.1E-11
na
2.9E-09
3.0E-09
Lead
na
na
na
na
Manganese
2.8E-13
na
3.3E-12
3.6E-12
Nickel
2.2E-13
na
1.8E-12
2.0E-12
Zinc
2.0E-12
na
1.9E-10
1.9E-10
Abbreviations: d = day; na = not assessed; PAH = polycyclic aromatic hydrocarbons.
Table 5.3.3. Ingestion Exposure Estimates for Temporary Carcass Storage - Children 1 to
<2 Years Old
Ingestion Average Daily Dose (mg/kg d)
Drinking Water
Farm Produce
Fish
Total Ingestion
Total Dioxins/furans
na
na
na
na
Total PAHs
na
na
na
na
Arsenic
na
na
na
na
Cadmium
na
na
na
na
Chromium
na
na
na
na
Copper
8.7E-14
na
3.8E-12
3.9E-12
Iron
1.1E-10
na
3.7E-09
3.8E-09
Lead
na
na
na
na
Manganese
4.8E-13
na
4.2E-12
4.7E-12
Nickel
3.8E-13
na
2.2E-12
2.6E-12
Zinc
3.5E-12
na
2.4E-10
2.4E-10
Abbreviations: d = day; na = not assessed; PAH = polycyclic aromatic hydrocarbons.
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
Table 5.3.4. Ingestion Exposure Estimates for Open Burning - Adults
Chemical Species
Ingestion Average Daily Dose (mg/kg d)
Drinking Water
Farm Produce
Fish
Total Ingestion
Total Dioxins/furans
4.7E-26
3.1E-12
1.4E-13
3.2E-12
Total PAHs
1.2E-16
2.8E-07
1.6E-07
4.4E-07
Arsenic
7.4E-13
2.6E-08
5.0E-07
5.3E-07
Cadmium
1.2E-13
1.5E-10
7.5E-07
7.5E-07
Chromium
1.3E-10
9.7E-16
1.8E-04
1.8E-04
Copper
3.5E-13
na
5.0E-05
5.0E-05
Iron
1.1E-09
na
2.2E-02
2.2E-02
Lead
5.2E-15
1.7E-13
3.1E-07
3.1E-07
Manganese
6.1E-10
na
1.9E-05
1.9E-05
Nickel
4.3E-12
8.1E-15
3.7E-06
3.7E-06
Zinc
2.8E-11
1.7E-12
3.2E-04
3.2E-04
Abbreviations: d = day; na =
not assessed; PAH = polycyclic aromatic hydrocarbons.
Table 5.3.5. Ingestion Exposure Estimates for Open Burning - Children 1 to <2 Years Old
Chemical Species
Ingestion Average Daily Dose (mg/kg d)
Drinking Water
Farm Produce
Fish
Total Ingestion
Total Dioxins/furans
8.1E-26
4.6E-11
1.8E-13
4.6E-11
Total PAHs
2.1E-16
4.0E-06
2.0E-07
4.2E-06
Arsenic
1.3E-12
1.3E-07
6.4E-07
7.7E-07
Cadmium
2.0E-13
6.2E-10
9.4E-07
9.4E-07
Chromium
2.3E-10
2.8E-15
2.3E-04
2.3E-04
Copper
6.0E-13
na
6.3E-05
6.3E-05
Iron
1.9E-09
na
2.8E-02
2.8E-02
Lead
9.0E-15
5.2E-13
3.9E-07
3.9E-07
Manganese
1.1E-09
na
2.4E-05
2.4E-05
Nickel
7.5E-12
2.4E-14
4.7E-06
4.7E-06
Zinc
4.9E-11
4.3E-12
4.1E-04
4.1E-04
Abbreviations: d = day; na = not assessed; PAH = polycyclic aromatic hydrocarbons.
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Table 5.3.6. Ingestion Exposure Estimates for Air-curtain Burning - Adults
Chemical Species
Ingestion Average Daily Dose (mg/kg d)
Drinking Water
Farm Produce
Fish
Total Ingestion
Total Dioxins/furans
8.1E-26
4.4E-11
1.0E-11
5.4E-11
Total PAHs
3.1E-16
4.1E-10
1.8E-09
2.2E-09
Arsenic
1.3E-12
2.6E-08
9.7E-08
1.2E-07
Cadmium
8.7E-14
2.2E-11
5.9E-07
5.9E-07
Chromium
2.1E-10
4.1E-16
6.8E-05
6.0E-05
Copper
4.2E-13
na
2.5E-05
2.4E-05
Iron
1.2E-09
na
1.7E-03
1.6E-03
Lead
9.2E-14
8.1E-14
1.2E-07
1.2E-07
Manganese
1.1E-09
na
1.9E-04
1.9E-04
Nickel
5.8E-12
1.9E-15
7.4E-07
7.3E-07
Zinc
9.3E-11
2.2E-12
3.6E-04
3.5E-04
Abbreviations: d = day; na =
not assessed; PAH = polycyclic aromatic hydrocarbons.
Table 5.3.7. Ingestion Exposure Estimates for Air-curtain Burning - Children 1 to <2
Years Old
Chemical Species
Ingestion Average Daily Dose (mg/kg d)
Drinking Water
Farm Produce
Fish
Total Ingestion
Total Dioxins/furans
1.4E-25
6.7E-10
1.3E-11
6.8E-10
Total PAHs
5.4E-16
5.7E-09
2.3E-09
8.0E-09
Arsenic
2.2E-12
1.2E-07
1.2E-07
2.4E-07
Cadmium
1.5E-13
9.1E-11
7.4E-07
7.4E-07
Chromium
3.6E-10
1.2E-15
8.6E-05
7.6E-05
Copper
7.3E-13
na
3.2E-05
3.1E-05
Iron
2.1E-09
na
2.2E-03
2.0E-03
Lead
1.6E-13
2.4E-13
1.5E-07
1.5E-07
Manganese
1.8E-09
na
2.4E-04
2.4E-04
Nickel
1.0E-11
5.7E-15
9.3E-07
9.2E-07
Zinc
1.6E-10
5.9E-12
4.5E-04
4.5E-04
Abbreviations: d = day; na = not assessed; PAH = polycyclic aromatic hydrocarbons.
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Table 5.3.8. Ingestion Exposure Estimates for Burial - Adults
Chemical Species
Ingestion Average Daily Dose (mg/kg d)
Drinking Water
Farm Produce
Fish
Total Ingestion
Total Dioxins/furans
na
na
na
na
Total PAHs
na
na
na
na
Arsenic
na
na
na
na
Cadmium
na
na
na
na
Chromium
na
na
na
na
Copper
3.6E-13
na
4.9E-11
4.9E-11
Iron
1.0E-10
na
1.1E-08
1.1E-08
Lead
na
na
na
na
Manganese
8.4E-13
na
2.3E-11
2.4E-11
Nickel
2.0E-13
na
3.7E-12
3.9E-12
Zinc
8.6E-12
na
1.8E-09
1.8E-09
Abbreviations: d = day; na =
not assessed; PAH = polycyclic aromatic hydrocarbons.
Table 5.3.9. Ingestion Exposure Estimates for Burial - Children 1 to <2 Years Old
Chemical Species
Ingestion Average Daily Dose (mg/kg d)
Drinking Water
Farm Produce
Fish
Total Ingestion
Total Dioxins/furans
na
na
na
na
Total PAHs
na
na
na
na
Arsenic
na
na
na
na
Cadmium
na
na
na
na
Chromium
na
na
na
na
Copper
6.3E-13
na
6.2E-11
6.3E-11
Iron
1.7E-10
na
1.4E-08
1.4E-08
Lead
na
na
na
na
Manganese
1.4E-12
na
2.9E-11
3.0E-11
Nickel
3.5E-13
na
4.6E-12
5.0E-12
Zinc
1.5E-11
na
2.2E-09
2.2E-09
Abbreviations: d = day; na = not assessed; PAH = polycyclic aromatic hydrocarbons.
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Table 5.3.10. Ingestion Exposure Estimates for Compost Windrow - Adults
Chemical Species
Ingestion Average Daily Dose (mg/kg d)
Drinking Water
Farm Produce
Fish
Total Ingestion
Total Dioxins/furans
na
na
na
na
Total PAHs
na
na
na
na
Arsenic
na
na
na
na
Cadmium
na
na
na
na
Chromium
na
na
na
na
Copper
2.7E-14
na
2.5E-12
2.5E-12
Iron
7.5E-12
na
5.5E-10
5.6E-10
Lead
na
na
na
na
Manganese
6.3E-14
na
1.1E-12
1.2E-12
Nickel
1.5E-14
na
1.8E-13
2.0E-13
Zinc
6.4E-13
na
8.9E-11
9.0E-11
Abbreviations: d = day; na =
not assessed; PAH = polycyclic aromatic hydrocarbons.
Table 5.3.11. Ingestion Exposure Estimates for Compost Windrow - Children 1 to <2
Years Old
Chemical Species
Ingestion Average Daily Dose (mg/kg d)
Drinking Water
Farm Produce
Fish
Total Ingestion
Total Dioxins/furans
na
na
na
na
Total PAHs
na
na
na
na
Arsenic
na
na
na
na
Cadmium
na
na
na
na
Chromium
na
na
na
na
Copper
4.7E-14
na
3.1E-12
3.1E-12
Iron
1.3E-11
na
6.9E-10
7.0E-10
Lead
na
na
na
na
Manganese
1.1E-13
na
1.4E-12
1.5E-12
Nickel
2.6E-14
na
2.3E-13
2.6E-13
Zinc
1.1E-12
na
1.1E-10
1.1E-10
Abbreviations: d = day; na = not assessed; PAH = polycyclic aromatic hydrocarbons.
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
Table 5.3.12. Ingestion Exposure Estimates for Compost Application - Adults
Chemical Species
Ingestion Average Daily Dose (mg/kg d)
Drinking Water
Farm Produce
Fish
Total Ingestion
Total Dioxins/furans
na
na
na
na
Total PAHs
na
na
na
na
Arsenic
na
na
na
na
Cadmium
na
7.0E-09
9.7E-06
9.7E-06
Chromium
na
7.7E-10
1.8E-03
1.8E-03
Copper
na
na
5.0E-03
5.0E-03
Iron
na
na
2.0E+00
2.0E+00
Lead
na
4.0E-07
1.5E-04
1.5E-04
Manganese
na
na
2.2E-03
2.2E-03
Nickel
na
1.1E-08
1.6E-04
1.6E-04
Zinc
na
3.5E-06
2.0E-02
2.0E-02
Abbreviations: d = day; na = not assessed; PAH = polycyclic aromatic hydrocarbons.
Table 5.3.13. Ingestion Exposure Estimates for Compost Application - Children 1 to <2
Years Old
Ingestion Average Daily Dose (mg/kg d)
Drinking Water
Farm Produce
Fish
Total Ingestion
Total Dioxins/furans
na
na
na
na
Total PAHs
na
na
na
na
Arsenic
na
na
na
na
Cadmium
na
2.3E-08
1.2E-05
1.2E-05
Chromium
na
2.3E-09
2.3E-03
2.3E-03
Copper
na
na
6.3E-03
6.3E-03
Iron
na
na
2.5E+00
2.5E+00
Lead
na
1.2E-06
1.9E-04
1.9E-04
Manganese
na
na
2.7E-03
2.7E-03
Nickel
na
3.4E-08
2.1E-04
2.1E-04
Zinc
na
9.0E-06
2.5E-02
2.5E-02
Abbreviations: d = day; na = not assessed; PAH = polycyclic aromatic hydrocarbons.
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
Table 5.3.14. Ingestion Estimates for Infants with Formula Made Using Well Water3
Chemical
Species
Ingested Daily Dose (mg/kg d)
Open Burning
Air Curtain
Burial
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
livestock while grazing on short grasses, particularly by cattle, allows greater exposures than
incidental soil ingestion by humans (e.g., through hand-to-mouth contact).
Table 5.4.1 Exposure Pathways and Routes for Livestock Carcass Management Options
Exposure
Source
Conceptual Model Pathways for Carcass Management Options
Combustion based
Options
Burial
Composting
Off site
Options
Inhalation
1) Air —> Livestock
1) Air —> Livestock
1) Air —> Livestock
—
Incidental Soil
2) Air —> Soil—> Livestock
Ingestion
Groundwater
3) Ash —> Groundwater —>
2) Leachate —>
2) Leachate —>
Ingestion
Livestock
Groundwater —>
Livestock
Groundwater —>
Livestock
—
Ingestion of
4) Air —> Plants —>
3) Air —> Plants —>
3) Air —> Plants —>
Food Produced
Livestock
Livestock
Livestock
on the Farm
5) Air —> Soil —> Plants —>
4) Air —> Soil —>
4) Air —> Soil —>
—
Livestock
Plants —> Livestock
Plants —> Livestock
"—" = no exposure pathways.
Both on-site combustion-based options result in chemical ingestion by livestock. For on-site
combustion options, the MIRC-estimated concentrations of arsenic, cadmium, total PAHs, and
total dioxins/furans (by weight, not by toxic equivalency factors) in beef, pork, poultry, milk, and
eggs are listed in Tables 5.4.2 and 5.4.3. Data are not listed for chromium, copper, iron, lead,
manganese, nickel, or zinc because there are no available empirical transfer factors. Open-
burning results in somewhat higher concentrations released to air than air-curtain burning,
particularly for PAHs. One exception is that estimates of dioxins/furans created are slightly
higher for the air-curtain burning scenario because of the large quantities of wood burned
assuming a 4:1 ratio of wood to carcasses.
Table 5.4.2. Chemical Concentrations in Beef, Pork, and Poultry After Carcass
Management by Open Burning (550°C)
Chemical Species
Beef (mg/kg
wet wt.)
Total Dairy
(mg/kg wet wt.)
Pork
(mg/kg wet
wt.)
Poultry (mg/kg
wet wt.)
Eggs (mg/kg
wet wt.)
Arsenic
1.2E-05
5.5E-07
na
na
na
Cadmium
8.4E-09
6.8E-10
5.8E-10
5.2E-13
1.2E-14
Zinc
na
na
na
2.5E-12
2.5E-12
Total PAHs3
1.1E-03
3.6E-04
9.5E-05
3.0E-09
1.7E-09
Total Dioxin/furansb
1.5E-09
4.7E-10
1.2E-10
4.6E-17
2.6E-17
Abbreviations: wt = weight; na = not assessed; PAH = polycyclic aromatic hydrocarbons.
a Total PAHs calculated as sum of the products of individual congener concentrations and relative potency factors (RPFs).
b Total dioxins/furans calculated the same way using toxicity equivalency factors (TEFs or TEQs).
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
Table 5.4.3. Chemical Concentrations in Beef, Pork, and Poultry After Carcass
Management by Air-Curtain Burning (850°C)
Chemical Species
Beef (mg/kg
wet wt.)
Total Dairy
(mg/kg wet
wt.)
Pork (mg/kg
wet wt.)
Poultry (mg/kg
wet wt.)
Eggs (mg/kg
wet wt.)
Arsenic
1.2E-05
5.4E-07
na
na
na
Cadmium
1.2E-09
1.0E-10
8.4E-11
5.1E-13
1.2E-14
Zinc
na
na
na
3.5E-12
3.5E-12
Total PAHs3
2.7E-06
8.5E-07
2.2E-07
9.8E-12
5.6E-12
Total
Dioxin/furansb
2.1E-08
6.8E-09
1.8E-09
2.2E-15
1.3E-15
Abbreviations: wt = weight; na = not assessed; PAH = polycyclic aromatic hydrocarbons.
a Total PAHs calculated as sum of the products of individual congener concentrations and relative potency factors (RPFs).
b Total dioxins/furans calculated the same way using toxicity equivalency factors (TEFs or TEQs).
MIRC-estimated concentrations are not compared to tissue-based toxicity benchmark
concentrations for livestock or wildlife for several reasons:
¦ Tissue-based toxicity values for animals usually are specified in terms of the concentration
in specific organs or tissues, often kidney, liver, brain, and fat deposits, because few if any
chemicals distribute equally throughout the body. HHRAP-MIRC-estimated concentrations
are based on soil-livestock transfer factors intended to reflect concentrations in
muscle/meats (and in milk, cheese, and eggs) as consumed by humans. Those concentrations
are likely to differ from those in kidney, liver, brain, or lungs, which often are the initial
organs damaged by toxic chemicals.
¦ Although dose-response toxicity reference values are available for some chemicals for birds
and small mammals, scaling of those doses to large-bodied, herbivorous, ungulates would
introduce uncertainty arising from substantial differences in digestive processes. The
available TRVs derived for wildlife, the highest no-observed-adverse-effect levels and the
lowest-observed-adverse-effect levels (LOAELs) from laboratory toxicity tests for growth,
reproduction, and survival are not necessarily indicative of herd- or population-level
impacts. The relationships to doses that might impact agricultural productivity or livestock
marketability would introduce another source of error.
¦ Inhalation of air-borne chemicals by livestock is not likely to cause adverse health effects
given the short (48-hr) exposure duration. Moreover, inhalation benchmarks to protect
individual humans from irritation (eyes, nose, throat, lungs) are likely to be much lower than
inhalation benchmarks to protect long-term health of humans or livestock.
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
1.1.2. Environmen posiire
To examine the potential for adverse effects in wildlife exposed to chemicals originating from
the on-site carcass management options, the estimated concentrations of chemicals in soils and
the lake associated with each option are compared to available ecological benchmarks.
For soils, this assessment uses USEPA's Superfund Ecological Soil Screening Levels (EcoSSLs).
The EcoSSLs are intended to screen chemical concentrations in surface soils for potential
impacts on wildlife, vegetation, and soil biota (e.g., earthworms, other soil invertebrates
important to soil aeration and nutrient recycling). Chemical bioavailability in soils to plants,
invertebrates, and vertebrates that ingest soils incidentally as they forage, depends on many
factors, including soil-specific characteristics. Some of the EcoSSLs are near background levels
(conservative assumptions used in their calculation); those values are of limited utility as a
screening tool. Despite the conservative nature of the EcoSSLs, they are several orders of
magnitude greater than the estimated concentrations of contaminants in surface soil resulting
from the carcass management options (Table 5.4.4). This suggests that use of any of the analyzed
carcass management options is not likely to pose risks to wildlife from the estimated
concentrations of chemicals in surface soil.
Under the CWA, USEPA's Office of Water develops National Ambient Water Quality Criteria
for the Protection of Aquatic Life (NAWQC-AL) and their uses. Criteria for many metals depend
on water characteristics, such as hardness or pH. NAWQC-AL for chronic exposures (assuming
neutral pH and hardness of 100 mg/L as CaCC>3 for chemicals for which those influence toxicity)
are provided in Table 5.4.5 along with estimated contaminant concentrations in the on-site lake
for each of the four on-site livestock carcass management options. For all chemicals and
livestock carcass management options, the estimated surface water concentrations are lower than
the chronic NAWQC-AL (Table 5.4.5). This suggests that chemicals reaching surface waters
from use of any of the analyzed carcass management options are unlikely to cause toxic effects
in aquatic life.
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
Table 5.4.4 Estimated Surface Soil Concentrations Compared with Ecological Soil
Screening Levels
Ecological Soil Screening Levels (mg/kg)a
Estimated Soil Concentration (mg/kg)
Species
Inverte
brate
Mammal
ian
Avian
Plant
Open
Burning
Air
Curtain
Burning
Initial
Applied
Compost
Applied
Compost
at 1 Year
Arsenic
nd
4.6
43
18
1.3E-12
3.2E-13
na
na
Cadmium
nd
nd
nd
nd
1.4E-10
1.4E-10
1.3E-03
6.9E-05
Chromium
nd
130
nd
nd
3.0E-10
1.3E-10
2.2E-02
2.4E-04
Copper
nd
230
120
13
6.9E-10
4.2E-10
8.9E-02
2.8E-03
Iron
nd
nd
nd
nd
4.0E-04
3.3E-05
1.6E+00
7.8E-01
Lead
1,700
56
11
120
2.0E-08
9.6E-09
1.4E-01
4.8E-02
Manganese
450
4,000
4,300
220
3.8E-06
4.2E-05
3.3E-02
1.6E-02
Nickel
280
130
210
38
1.3E-09
3.2E-10
3.3E-02
1.9E-03
Zinc
120
79
46
160
8.8E-09
1.2E-08
3.4E-01
1.9E-02
PAHs
nd
nd
nd
nd
5.4E-06
1.7E-08
na
na
Dioxin/
Furans
nd
nd
nd
nd
1.1E-13
5.4E-12
na
na
Abbreviations: wt = weight; nd = no data; na = not assessed; PAH = polycyclic aromatic hydrocarbons.
a Chemical-specific Eco-SSL reports can be found https://rais.onil.gov/documents/eco-ssl_fchemicalJ.pdf. For example, the Eco-
SSL document for nickel can be found at https://rais.oml.gov/documents/eco-ssl nickel.pdf. Also theoretically at
http://www.epa.gov/ecotox/ecossl/: however, that link seems to lead to ECOTOX only.
Water quality criteria for nutrients like phosphorus and nitrogen in lakes depend on attributes of
the ecoregion in which the lakes are located. For this reason, there are no NAWQC for nutrients,
so instead, this assessment uses nutrient criteria from the USEPA Ecoregions in which livestock
are raised in large numbers. These include USEPA Regions 4, 5, 6, 8, 9, 12, and 14. Total
phosphorus criteria ranged from 8-33 |ig/L while total nitrogen criteria ranged from 240-560
|ig/L across those six regions. The criteria are based on the 25th percentile reference conditions
for the region.
This assessment used the minimum values for each nutrient as criteria (Table 5.4.5). Nutrient
criteria exist for 10 of the 12 USEPA Ecoregions. For any given lake, the effect of added
nitrogen or phosphorus depends on the limiting factor for algal growth, which in turn depends on
surrounding land use, air deposition patterns, and hydrogeology. Although the burial option
might be expected to result in nutrients leaching to groundwater, and excessive concentrations of
chemicals in surface water, the estimated surface water concentrations did not exceed the lowest
nutrient criteria from any of the six USEPA Ecoregions. Ecoregional nutrient criteria for lakes
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
and reservoirs are published by ecoregion at http://www.epa.gov/nutrient-policv-
data/ecoregional-nutrient-criteria-documents-lakes-reservoirs.
In contrast to the estimated concentrations of a chemical in water pumped from a groundwater
well, which are constrained to a well-intercept diameter of 0.2 m, surface water concentrations
depend entirely on the relative volume and configuration of the chemical's source and the volume
and shape of the surface water. Ponds less than 91 m in diameter (e.g., a few acres total) might
intercept almost all of a groundwater plume from carcass burial (see Figure 5.4.1; note different
scales for the single lake on the left and the two smaller lakes on the right side of the figure). In a
worst-case environmental setting with evaporation and no additional water sources, a pond might
develop chemical concentrations close to the original leachate concentrations. Lakes larger than
the 40.5 ha (100 ac, more than 600 m diameter) lake assumed in this assessment would
accumulate less. Larger, longer burial trenches could result in higher amounts of chemicals
transported to nearby surface waters. Many additional factors, including geometry and size of the
source and those of the lake, influence the process of groundwater recharge and the potential for
contamination of a lake.
This assessment qualitatively considers disruption of a lake ecosystem, with possible
eutrophication from nutrient loading and possible oxygen depletion and fish kills from increased
biological oxygen demand (BOD) and chemical oxygen demand (COD) discharge to the water
column. The major source of BOD and COD discharged to the lake is expected to be an on-site
burial trench. The degree to which a surface water can maintain equilibrium in the presence of
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
Table 5.4.5. Chemical Concentrations in Surface Water compared to National Ambient
Water Quality Criteria for Aquatic Life - Criterion Continuous Concentration (CCC) (i.e.,
for chronic exposures)
NAWQC-
AL
(fig/L)
Concentrations in Surface Water (jig/L), Large Lake (40.5 ha)
Chemical
Species
Storage
Pile
Open
Burning
Air
curtain
Burning
Burial
Compost
Windrow
Compost
Application
Total
Dioxins/furans3
nd
na
9.3E-13
3.2E-11
na
na
na
Total PAHsb
nd
na
2.0E-04
4.7E-07
na
na
na
Arsenic
1.5E+02
na
2.3E-04
4.3E-05
na
na
na
Cadmium
nd
na
1.4E-04
1.1E-04
na
na
1.9E-03
Chromium
1.1E+01
na
6.1E-03
2.1E-03
na
na
6.3E-02
Copper
9.0E+00
1.6E-10
2.6E-03
1.3E-03
2.5E-09
1.3E-10
2.6E-01
Iron
1.0E+03
1.9E-07
1.4E+00
1.0E-01
7.1E-07
3.5E-08
1.3E+02
Lead
2.5E+00
na
1.2E-04
4.5E-05
na
na
5.9E-02
Manganese
nd
8.6E-10
5.0E-03
4.9E-02
5.8E-09
2.9E-10
5.6E-01
Nickel
5.2E+01
6.9E-10
1.4E-03
2.8E-04
1.4E-09
7.1E-11
6.3E-02
Zinc
1.2E+02
6.3E-09
1.1E-02
1.2E-02
6.0E-08
3.0E-09
6.8E-01
Ammonium
—
2.5E-03
na
na
6.6E-02
3.3E-03
na
Chloride
2.3E+05
1.2E-03
na
na
1.5E-02
7.4E-04
na
Phosphorus
8.0E+000
4.4E-04
na
na
7.0E-03
3.5E-04
na
Potassium
Nd
9.0E-04
na
na
1.2E-02
6.2E-04
na
Sodium
Nd
7.6E-04
na
na
1.2E-02
6.0E-04
na
Sulfate
Nd
2.7E-03
na
na
4.6E-02
2.3E-03
na
Sulphur
Nd
5.7E-04
na
na
1.0E-02
5.0E-04
na
Total Nitrogen
2.4E+020
2.2E-02
na
na
2.8E-01
1.4E-02
na
Abbreviations: NAWQC-AL = National Ambient Water Quality Criterion - Aquatic Life; ha = hectares; nd = no data; na = not
assessed; PAHs = polycyclic aromatic hydrocarbons.
a Human toxicity equivalency factors (TEFs or TEQs) relative to 2,3,7,8-TCDD are applied to individual congeners then
concentrations are summed for the group.
b Totaled from individual congeners using human relative potency factors (RPFs) relative to benzo(a)pyrene (BaP).
c Lowest of six USEPA regional nutrient criteria expressed at the 25th percentile of observed effects (USEPA Regions 4,5,8, 9,
12, and 14 considered representative of livestock raising states).
excess nutrients, without changes to the balance of aquatic plant and animal life, depends on
many factors. These factors include the nutrient status of the water body, which nutrient(s) are
limiting for aquatic plant growth, and whether other nutrient sources (e.g., fertilizer, manure
runoff) are present. The degree to which oxygen might be depleted with input of materials with
measureable BOD and COD also depends on many factors, particularly temperature (colder
waters can hold more oxygen at saturation than warmer waters). Stress from BOD and COD
would be expected only for smaller ponds. The larger lake simulated in this assessment (40 ha or
100 ac) is unlikely to be disrupted by the types or amounts of chemicals associated with the
carcass management options. This suggests that use of any of the analyzed on-site carcass
management options is not likely to pose risks of eutrophication or disruption of lakes 40 ha or
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
larger from the estimated amounts of chemicals that might enter the environment when setbacks
of 30.5 m (100 ft) or more are followed, including the area where compost is applied.
Burial
Trench 91-4 rri
' ' I 1
100 acre lake
(40.5 hectares)
Burial
Trench
1 acre lake
(0.4 hectares) \ ¦
Burial
Trench
-i-
10 acre lake
(4.05 hectare)
636 m
Figure not to scale
201 m
Figure 5.4.1 Relationship between emerging contaminant groundwater plume from carcass
burial trench to surface water bodies of various sizes.
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
6. Exposure Es icrobes
As living organisms, microbial dynamics and fate in the environment are very different from
chemicals. Their survival is modified by environmental conditions, and various microbes might
be affected very differently by the same conditions. In addition, measurements of the number of
microorganisms present in a contamination source (in this instance, livestock carcasses) and at
the time of human exposure are rarely available (Lammerding and Fazil 2000; Joung et al. 2013).
Because of differences in the behavior of microbes and chemicals in the environment and in data
availability, the chemical fate and transport models and methods described in Section 4 are not
suitable for estimating microbial exposures associated with livestock carcass storage and
handling, transportation, or the livestock carcass management options. This section describes the
methods used to estimate human, livestock, and ecological exposures to microbes.
Human and livestock exposure to microbes is likely only from ingestion of groundwater from the
drinking water well; all other routes of exposure to microbes were determined to be negligible or
to be unquantifiable. Ecological exposure to microbes may occur through multiple routes and
mediums and these routes were unable to be quantitatively assessed. Published screening-level
models for estimating exposure to pathogens, with many parameter values selected to be
representative nationwide like chemical screening models (e.g., USEPA 2005a), are not available
for microbes. Existing pathogen fate and transport models are limited in number and require a
significant amount of refinement and user input of parameter values, many of which are
unknown in Phase 1. In addition, each of the microbes identified as a potential hazard in Table
2.4.4 could have unique inputs for these models (e.g., initial loading at the time of death,
microbial suspension in porous media, surface attachment, survival curves), many of which have
not been defined for some of the pathogens identified in Table 2.4.4. Assumptions for any of
these input values could significantly alter the modeling results.
In the absence of quantitative data on important modeling inputs such as the initial loading
concentration associated with healthy livestock and rate of growth/die-off for each pathogen, the
assessment uses less refined quantitative approaches relying on simplified assumptions about the
initial loading, decay rate, ingestion rate (human and cattle, where appropriate), adult body
weight, and vertical fate and transport efficiency. Data for those parameters were gathered for
three pathogens: prions (a highly thermotolerant microorganism with a high rate of
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
environmental survival and small diameter); Bacillus anthracis (a spore-forming bacterium also
with high thermal tolerance and high environmental survival); and E. coli 0157:H7 (a
pathogenic zoonotic species of bacteria commonly found in the gut of cattle and swine and
frequently identified as the etiologic agent in cases of waterborne and foodborne illnesses in
humans).
The assessment estimates initial loading concentration in two ways depending on the availability
of quantitative data for the specific pathogen. This assessment uses land-applied Class B
biosolids measurements as the loading concentration, if these data are available. In the absence
of measured concentrations of the pathogen in biosolids, the assessment estimates initial loading
concentration based on published values for the infectious dose in 50% of cattle. The initial
loading concentration is assumed to be one-half of the infectious dose, because the cattle are
assumed free of signs or symptoms of illness when the natural disaster strikes. Human exposure
factor values (e.g., for body weight, water ingestion) are mean values obtained from the most
recent version of USEPA's Exposure Factors Handbook (USEPA 2011). A step-wise equation is
used to calculate the density of prions, B. anthracis, and E. coli 0157:H7 in groundwater at the
time of ingestion from the initial release to groundwater through one year of exposure.
Simple methods evaluate exposures to livestock and wildlife that survive the natural disaster. For
microbes, a step-wise equation estimates the ingestion of the three selected pathogens with
groundwater used for watering livestock. The variables in this equation reflect the ingestion rate
and body weight of livestock, and there are separate calculations for cattle for winter and
summer because the ingestion rate varies during the course of a year.
An initial list of potential microbial hazards that could be present in livestock that are not
exhibiting symptoms of infection or disease (and are not known to have been exposed to a
foreign animal disease agent or other infectious agent) is presented in Section 2.4.2, Table 2.4.4.
Some of the agents in that list are not expected to survive carcass storage and handling,
transportation, and management. For example, microbes that would not survive the thermal
processes associated with combustion-based and rendering processes were removed from the list
of potential microbial hazards for those management options. For the reasons given below, a
subset of representative microbes was selected from the larger set of microbes identified in
Section 2.4.2 for inclusion in the exposure assessment:
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
¦ Prions - Prions (proteinaceous infectious particles) are unique pathogens that have no
nucleic acid and thereby differ from viruses, bacteria, and other pathogens. Prions are
resistant to procedures that break down nucleic acid; they are considered the most resistant
microbial agents in the list of potential hazards presented in Table 2.4.4. Prions also can
survive relatively high combustion temperatures. For this reason, prions are likely to survive
temporary storage, handling, and transportation for all management options. Prions also are
likely to survive carcass open-burning, burial, and composting. The concentration of prions
in environmental media in areas where TSEs are endemic is largely unknown due to the
limited ability to detect prions in or extracted from environmental samples. Natural biotic
and abiotic mechanisms of protein degradation might reduce prion infectivity in the
environment.
¦ Bacillus anthracis - While spore-forming organisms such as B. anthracis are destroyed by
the combustion processes characteristic of some management options, they can survive the
temperatures reached during livestock composting even though these temperatures can
inactivate other pathogens. In addition to surviving the composting process, spores of B.
anthracis can also persist in air, soil, and water, and are assumed to be present during
carcass storage and handling, transportation, and on-site unlined burial (Stanford et al.,
2015). In the United States, inhalation anthrax generally is associated with exposure to
wool, bone, animal hides, and bioterrorist attacks (Griffith et al. 2014).
¦ Escherichia coli strain 0157:H7 - E. coli 0157:H7 can account for up to 1% of the
bacterial population of the gut in ruminant animals, including cattle. The gastrointestinal
system can act as a reservoir for the pathogenic bacterium E. coli strain 0157:H7 (Callaway
et al. 2009). Approximately 30% of feedlot cattle shedE. coli 0157:H7, and high
concentrations of E. coli 0157:H7 are reported in cattle manure (Callaway et al. 2009). E.
coli 0157:H7 has been detected in cattle feces and Class B land-applied biosolids
(Hutchinson et al. 2005; Pepper et al. 2010). Hutchinson et al. (2005) reported a
concentration of 1,200 colony forming units (CFU) of E. coli 0157:H7 per gram of cattle
feces and Pepper et al. (2010) reported a concentration of 1 CFU of E. coli 0157:H7 per 1
gram dry biosolid. E. coli 0157:H7 excreted in cattle feces can be transmitted to humans
and cause illness (Matthews et al. 2013). The incidence of human illness caused by E. coli
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0157:H7 is high, with an estimated 63,000 cases occurring in the United States each year
(Scallan et al. 2011). However, it is unclear how many of these illnesses are associated with
transmission from cattle feces. E. coli 0157:H7 can persist in air, soil, and water, but is
inactivated by the thermal processes characteristic of the open-burning, air-curtain burning,
and composting processes. However, E. coli 0157:H7 could remain viable during the burial
process and during storage, handling, and transportation.
Assessment of pathogen exposure considers properties related to the fate and transport of
microbes in the environment. It is not feasible to identify and consider every parameter that
affects fate and transport for every pathogen mentioned in this exposure assessment. Instead,
data on four properties of pathogens are aligned with the variables identified in the equations
used in the exposure estimation for pathogens (described, when available, in Section 6.2 and 6.3
for each media compartment). The assessment uses quantitative data from the literature for four
properties (presented in Table 6.1.1):
¦ Size of the microorganism: Particle size affects rates of diffusion and movement of the
microbes with fluids through soil, dispersion in air, and suspension in water.
¦ Survival/persistence: The growth and/or inactivation of the microbe in the environment
outside of livestock carcasses affect its ability to reach living animals or humans. Pathogens
can become dormant or shift to environmentally long-lived forms, such as endospores. For
some types of microbes, the concentration of viable agents can be significantly reduced after
release to the environment. For example, viruses are not able to replicate outside of a host
cell and therefore are not expected to multiply in air, water, or soil. Microbial survival in the
environment is often linked to the ambient pH. In contrast, microbial growth and
reproduction is linked to the availability of water and/or nutrients. For those reasons, the
broad criterion of "survival" facilitates assessment rather than focusing on variability among
microbial populations or precise survival mechanisms.
1 Illness(es) caused and infectious dose: Infection with a specific microbe is typically
associated with specific illnesses and health effects. Infectious dose (ID) is the number of
microbes required to cause infection in the host, in this case in healthy adult humans or
healthy adult cattle. The ID50 refers to the dose of an infectious organism required to
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Table 6.1.1. Evaluation Factors Included in the Exposure Assessment for Microbes.
Category
Organism Name
Size
Dlness(es) Caused; Infectious
Dose (ID)
Survival Rate
References
Bacteria - Gram
negative
Escherichia coli
0157:H7
0.25 - 1 (im
wide; 2 (im
long
Illness: Range from mild
gastrointestinal illness, life-
threatening disease hemolytic
uremic syndrome (HUS)
IDso3 Humans: 10 -100
organisms
IDso Cattle: <300 organisms
Cattle manure amended soil:
1.25 x 10"3organisms/hr
Air: 0.2 organisms/hr
Water: 3.12 x 10~3 organisms/hr;
1.31 x 10 2 organisms/ hr with a
90% reduction in 3.18 days
Filip et al. 1988;
Himathongkham et al.
1999; Besser et al. 2001;
Hutchinson et al. 2005;
Nyberg et al. 2010;
Gurianet al. 2012
Bacteria - Spore-
forming
Bacillus anthracis
1 - 2 (im
(diameter)
Illness: Cutaneous anthrax,
gastrointestinal anthrax,
inlialational anthrax
IDso Humans: 8,000-50,000
(inhalation); generally in the
1,000s or 10,000s spores for other
exposure routes
IDso Cattle: < 10 spores in
susceptible herbivores
to > 107 spores in more resistant
livestock species(administered
parenterally)
Human Sewage: 1.74 x 104
organisms/hr
Soil (moist): 8.42 x 10"5
organisms/hr
Water: 1.14 x 10~4 organisms/hr
Air: 4.64 x 107 organisms/hr
Sinclair et al. 2008;
WHO 2008
Prion
Pj-pSc
10 - 20 mn
wide; 100 -
200 nrn
long
Illness: In cattle, BSE; In humans,
vCJD or nvCJD
IDso Humans: Unknown
IDso Cattle: 5.5 x 10 3 particles
Soil: 7.61 x 10~5 organisms/hr
Air: Unknown
Water: 0.0069 organisms/hr
Brown and Gajdusek
1991; Miller etal. 2004;
Yamamoto et al. 2006;
Miles et al. 2011
Abbreviations: CFU = colony forming units; hr = hour; BSE, bovine spongiform encephalopathy; CJD, Creutzfeldt-.Takob disease; v, variant; nv, new-variant.
a Hie infective dose of microorganisms that will cause 50% of exposed individuals to become ill.
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produce infection in 50 percent of the experimental subjects. In some instances, the ID50 is only
available for healthy adult cattle and is not available for humans.
¦ Available loading data: The concentration and distribution of the microbe in livestock
carcasses is an important element of evaluating exposure. Data on the concentration of microbes
in cattle manure should be representative of materials in the gastrointestinal tract. For prions
and B. anthracis, measured data on the concentration of these agents in cattle or biosolids was
limited. Many laboratory studies relied on spiked samples with known starting concentrations
selected by the researchers (e.g., a concentration associated with an adverse effect on human
health or livestock. The laboratory-spiked samples did not reflect loading associated with
natural populations present in healthy cattle (Kinckley et al. 2008; Jacobson et al. 2009).
Assumptions are made on initial carcass concentrations or prions and B. anthracis using ID50
values. This approach has been used in other published risk assessments and exposure analyses
(Gale et al. 1998; Grist 2005). The loading value for E. coli 0157:H7 is based on its reported
concentration in land-applied Class B biosolids (Pepper et al. 2010).
The use of data on surrogates16 for assessing fate and transport is common when quantitative data
on a specific pathogen is not available (Sinclair et al. 2012). In Phase 1 of this assessment of
carcass management options (i.e., mass livestock mortality from a natural disaster), initial
loading for pathogens are levels that could occur in healthy livestock. Concentrations of common
surrogates for B. anthracis and E. coli 0157:H7 would result in a gross overestimation of the
initial loading in healthy livestock. Fecal coliforms and total coliforms, common surrogates for
E. coli 0157:H7, are abundant in the environment and their presence does not necessarily
indicate the presence of virulent pathogens (Ashbolt et al. 2001). Measured concentrations of
fecal coliforms or total coliforms present in healthy cattle would likely be greater than
concentrations of E. coli 0157:H7 present in healthy livestock killed during a natural disaster. B.
anthracis is generally not measured because it presents a significant threat to public health.
Instead, surrogates of B. anthracis, including other species of Bacillus such as, B. cereus, B.
putida, B. arvi, B. pumilus, B. sphaericus, B. psychodurans, B. subtilis, and B. foetidans, have
16 A surrogate is an organism, particle, or substance used to evaluate the fate of a pathogen in a specific environment. Pathogenic
organisms, nonpathogenic organisms, and innocuous particles have been used as surrogates for a variety of purposes, including
studies on survival and transport as well as for method development and as "indicators" of certain conditions (Sinclair et al.
2012).
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been studied to understand the fate and transport of B. anthracis spores in the environment
(Greenberg et al. 2010). However, investigators have measured decay rates for B. anthracis (i.e.,
inactivation of spores) in a variety of media; thus data from surrogate microbes were not needed.
Although data on B. anthracis loading in healthy livestock populations was not available, data on
surrogates would not have provided an accurate measure of B. anthracis in healthy livestock.
Like fecal coliforms and total coliforms, Bacillus species are abundant in cattle and use of a
surrogate would overestimate the initial concentration for B. anthracis in healthy cattle (Wu et al.
2005). Therefore, data specific to the three pathogens assessed were favored over the use of data
on general surrogates which are more abundant in the natural flora of livestock
The remainder of this section is organized in three subsections. A summary of the exposure
pathways included in the microbial exposure assessment is provided in Section 6.1. Evaluations
of source conditions and microbial properties allowed elimination of several pathways because
they pose negligible risks of illness in humans or livestock in this scenario. For the remaining
exposure pathways, availability of quantitative data determined whether a quantitative or
qualitative assessment of exposure can be done. The decision criteria used for these
determinations are also discussed in Section 6.1.
Section 6.2 describes how potential human exposures to the three microbes could occur, and
where data allow, how possible microbial exposures were estimated for livestock carcass storage,
handling, and transportation for each of the carcass management options.
Section 6.3 discusses livestock and wildlife exposures to microbes.
There were insufficient data to quantitatively compare possible exposure levels to health
protective benchmarks.
6.1, Sum man of Human Exposure Pathways for Microbes
Pathways of human exposure to microbes assessed for this report are highlighted in bold in Table
6.1.2. Pathways with quantified exposures are indicated with bold type and endnote "a."
Exposure pathways indicated by endnote "b" in Table 6.1.2 are assumed to be negligible.
Exposure pathways indicated by endnote "c" are assumed to be adequately controlled by existing
pollution control regulations or use of PPE (i.e., gloves, dust mask). The rationale for excluding
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Table 6.1.2. Human Exposure Pathways for Livestock Carcass Management Options - Microbes
Exposure
Exposure Pathways Transportation and
Handling Activities
Exposure Pathway
s Management Options
Route and
Medium
Carcass
Handling
Temporary
Carcass
Storage
Carcass
Transport
ation
Open Burning
Air curtain
Burning
Burial
Composting
Off site
Incineratio
n
Off site
Landfillin
g
Rendering
Inhalation
1) Air —>
Inhalation0
1) Air —>
Inhalation0
2) Leachate —>
Soil —> GW —>
Aerosol
1 )Aerosolb
1) Airb
2) Ash —> GW
—> Aerosolb
1) Ahb
2) Ash—> GW
—> Aerosolb
1) Ahb
2) Leachate
—> GW —>
Aerosolb
1) Ahb
2) Compost
—> GW —>
Aerosol15
1) Air0
1) Ah0
1) Ah0
Direct
Ingestion
2) Hand-to-
mouth oral
contact0
—
—
—
—
—
—
—
—
—
Incidental
Soil
Ingestion
—
—
—
3) Ah —> Soilb
3)Air^Soilb
—
—
2) Ah —>
Soil0
—
—
Fish
Ingestion
—
3) Leachate —>
Soil —> GW —>
SW -> Fish
ingestionb
—
4) Ah —> SW
->Fishb
5) Ah —> soil —>
SW -> Fishb
6) Ash —> GW
—> SW —> Fishb
4) Air^ SW —>
Fishb
5) Air -> Soil
—> SW —> Fishb
6) Ash—> GW
—> SW —> Fishb
3) Leachate
—> GW —>
SW Fishb
3) Compost
Soil ^
SW Fishb
4) Compost
—> GW —>
SW Fishb
3) Ah —>
SW Fish0
4) Ah —>
Soil SW
Fish0
—
—
Ground-
water
Ingestion
—
4) Leachate —>
Soil —> GW —>
Drinking
water
ingestion3
—
7) Ash -~ GW1
7) Ash —> GWb
4) Leachate
—> GWa
5) Compost
^Leachate
—> GWa
—
—
—
Ingestion
ofFood
Produced
on the
Farm
—
—
8) Ah —> Plants/
Livestockb
9) Ah —> Soil
—> Plants/
Livestockb
10) Ash —> GW
—> Livestockb
8) Air —> Plants/
livestockb
9) Air -> Soil
—> Plants/
Livestock15
10) Ash—> GW
—> Livestock15
5)Air^
Plants/
Livestock15
6) Leachate
—> GW —>
Livestock15
6)Air^
Plants/
Livestock15
7) Compost
-> Soil ^
GW —>
Livestock15
5) Ah —>
Plants/
Livestock0
6) Ah —>
Soil —>
Plants/
Livestock0
2)Air^
Plants/
Livestock0
2)Air^
Plants/
Livestock0
Dermal
Contact
3) Dermal
contact0
-
—
—
—
—
—
—
—
Abbreviations: "—" = no exposure pathways; SW = surface water; GW = groundwater.
Note: Exposure pathways shown in bold were included in the quantitative exposure assessment.
a Quantitative assessment conducted; results are presented in Section 6.2. b Potential exposures are assumed to be negligible based on source conditions or microbial properties.
c Environmental releases or exposures are assumed to be adequately controlled by existing pollution control regulations or use of personal protective equipment.
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pathways from further evaluation (endnotes "b" and "c") is discussed in more detail below.
Exposures along pathways in Table 6.1.2 indicated by Table endnote "b" are assumed to be
negligible for the reasons discussed below. To avoid repetition, the reasons are grouped by
exposure pathway and medium. Thermal inactivation is discussed first, however, because it
affects pathways associated with five carcass management options: the on-site open-pyre
burning, air-curtain burning, composting, and the off-site incineration and rendering options.
¦ Thermal Inactivation - The temperatures reached and the duration of high temperatures for
on-site air-curtain burning and off-site incineration management options are high enough to
destroy the microbes identified as potential hazards, including prions. However, the burn
temperature reached during on-site open burning (e.g., 550°C) is lower than the temperatures
reached during on-site air-curtain burning (e.g., 850°C) and off-site incineration (e.g.,
>1,000°C). While most pathogens would be inactivated or destroyed at 550°C over two days,
more heat-resistant prions would not be inactivated. Similarly, many pathogens are
inactivated by the temperatures characteristic of on-site composting (e.g., at least 55°C for
three or more days), but prions or spores formed by some types of bacteria (e.g., B.
anthracis) are unlikely to be inactivated by the lower heat associated with composting.
Thermal inactivation of pathogens sufficient to pose a negligible risk of illness is likely for
four carcass management options and some or all of the associated pathways identified in
Table 6.1.2:
• Open burning, exposure pathways 1-10; two of the three pathogens considered for the
natural disaster scenario are excluded, prions are included
• Air-curtain burning, exposure pathways 1-10; all three pathogens considered for the
natural disaster scenario are excluded
• Composting, exposure pathways 1-7; one pathogen, E. coli 0157:H7, is included; two
are excluded from further evaluation: spore-forming bacteria and prions
• Off-site incineration, exposure pathways 1- 6; all three pathogens considered for the
natural disaster scenario are excluded
¦ Inhalation - Pathways that can lead to inhalation of aerosolized well water by humans (e.g.,
showering, boiling) are not quantified for exposure pathways associated with carcass
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transportation and handling activities or the management options. For temporary carcass
storage and the combustion-based, composting, and burial options, those pathways are
assumed to be insignificant compared with ingestion of well water (e.g., drinking,
reconstituting dried foods). Boiling foods would inactivate bacteria in the well water, but not
inactivate prions and bacterial spores. Based on simulated combustion studies, prions
generally are not released directly to air during the burning process (Brown et al. 2004).
Although survival of prions in air has been observed (Haybaeck et al. 2011; Xavier 2014),
the small initial concentration in healthy livestock suggests that a negligible concentration of
viable prions would be released to air from an open pyre. Moreover, humans are assumed to
be at least 100 feet from the pyre (Turnbull et al 1998). Inhalation exposures, therefore, are
not assessed for the management options, exposure pathways, and potential microbial
hazards specified below:
• Open burning, exposure pathways 1-2; prions
• Temporary carcass storage, exposure pathway 2; all three pathogens considered for the
natural disaster scenario
• Burial, exposure pathway 1; all three pathogens considered for the natural disaster
scenario
• Composting, exposure pathways 1 - 2; all three pathogens considered for the natural
disaster scenario
¦ Soil ingestion - With the on-site open-burning option, microbes initially released to air with
soot are assumed to be deposited onto soils surrounding the pyre during the 48 hours of
combustion. Accidental ingestion by workers (e.g., via hand-to-mouth contact) could occur
during carcass combustion activities. Accidental ingestion by farm residents could occur
either during or after those activities. For workers, the exposure is avoided by using
disposable gloves and other personal protective equipment (as required in this assessment).
Farm residents are unlikely to spend significant time on a daily basis in contact with the soil
near the combustion site which effectively limits the risk of soil ingestion exposure. Children
should not be allowed access the work site, so even if they engage in geophagy, they are
unlikely to directly consume contaminated soil. Consequently, ingestion of soil is considered
an incidental and negligible exposure pathway for workers and adult and child farm
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residents. Incidental soil ingestion, therefore, is not assessed for the one possible remaining
management option, exposure pathway, and type of microbe:
• Open burning, exposure pathway 3; prions.
¦ Fish ingestion - Fish in the on-site farm lake can be exposed to pathogens if contaminated
groundwater enters the lake or when pathogens are deposited via air to the lake's surface.
Groundwater could be contaminated if pathogens move from the carcasses through the soil
and reach groundwater. Pathogens can reach surface soils via direct deposition from air or
can reach subsurface soils from percolation of rainwater through buried ash or leaching of
fluids from buried livestock carcasses. A significant reduction in the concentration of viable
microbes released from carcasses is expected for microbes that require a living host to be
active. Microbes also are likely to adhere to particles in the environment. Inactivation and
attachment to soil particles can significantly reduce the number of viable microbial agents
transported from buried carcasses or buried ash through the subsurface soil to groundwater.
Therefore, the discharge of groundwater to the lake, and the subsequent entry of pathogens
into the aquatic food web, is considered negligible.
Some pathogens can bioaccumulate in fish when fish consume bacteria and phytoplankton
(to which microbes can adhere) are present in the aquatic environment. Microbes can also
accumulate in filter-feeding benthic organisms, including shellfish, that might be collected
for human consumption. Shellfish supported by freshwater ponds, like the one at the
hypothetical farm, and consumed by humans, appear to be limited to crayfish, which are
detritus feeders and scavengers. The consumption of undercooked or raw crayfish has been
linked to human illness from pathogens in the crayfish, but not to any of the pathogens
included in our list of potentially hazardous microbes associated with on-site open burning
and on-site unlined burial. Some pathogens associated with livestock, including
Mycobacterium spp., E. coli 0157:H7, Salmonella spp., Clostridiumperfringens, and
Campylobacter spp., are linked to foodborne illness in humans following the consumption of
fish (Novotny et al. 2004). Outbreaks usually occur if the fish are inadequately cooked, or
fish products are contaminated after/during their processing (Novotny et al. 2004).
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There have been concerns that scrapie-causing prion protein (PrPSc) can cause diseases in
animals of different taxa, such as fish; however, the passage of disease is usually impaired by
a taxonomic barrier. Laboratory research indicates that prions for mammalian diseases do not
infect fish (see Ingrosso et al. 2006). Moreover, if fish were to become infected, they could
not spread this disease to mammalian species. Several in vitro and in vivo experiments have
concluded that fish tissues taken at different times after parenteral or oral inoculation with
scrapie-causing prion protein (PrPSc) did not induce disease in mice directly inoculated with
these infected fish tissues (Ingrosso et al. 2006). Should prions produce infection in fish, the
brain and nervous system would be targeted. Humans would need to consume those tissues to
become infected, and those parts of the fish are generally not consumed. It is unlikely that
prions would pose a risk to humans if fish from the on-site pond were consumed.
Fresh water sources that support harvesting of bivalves and fish for human consumption
would be negligibly affected by even mass-morality carcass management locations. Fish and
shellfish harvesting areas provide substantial dilution water. Many species/strains of
microbes that cause infection in cattle do not produce infection in fish or shellfish. In
addition, the use of proper cooking temperatures and holding times is highly likely to
inactivate all pathogens that might be present in fish. Thus, human exposure via aquatic
animals is not evaluated for any of the carcass management options. Specifically, the fish
ingestion pathway was not evaluated for the management options and potential microbial
hazards specified below:
• Temporary carcass storage, exposure pathway 3; all three pathogens considered for the
natural disaster scenario
• Open burning, exposure pathways 4-6; prions only
• Burial, exposure pathway 3; all three pathogens considered for the natural disaster
scenario
• Composting, exposure pathways 3-4; all three pathogens considered for the natural
disaster scenario
¦ Ingestion of food produced or grown on the farm - Pathways were identified by which
farm-grown produce might be contaminated with pathogens for on-site open burning, air-
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
curtain burning, burial, and composting options. Unlike chemicals, well-defined models for
deposition of pathogen particles on plant surfaces or uptake of pathogens by plant roots are
not available for microbes. Potential human exposures depend on loading concentrations,
survival, and transport of microbes in each segment of food production. Initial loading
concentrations are assumed to be low for all of the microbes considered in this exposure
assessment. The assessment also assumes an initial reduction in the concentration of viable
infectious microbes when the microbes are released to air, followed by additional reductions
due to dilution as the microbes move along the pathways presented in Table 6.1.2.
Our conceptual model includes pathways with aerosolized microbes deposited on the surface
of plants. There is some evidence that human enteric pathogens interact with plants and the
plant environment (Lim et al. 2014). Human enteric pathogens can trigger plant defenses, but
recent evidence shows that some human pathogens, such as Salmonella spp. and E. coli, can
overcome plant defenses (Lim et al. 2014). However, a significant reduction in the
concentration of pathogens reaching plants for human consumption is anticipated because
pathogen movement in the soil is limited, and Salmonella spp. and E. coli 0157:H7 lose
viability when in air instead of in a living host. Thus, only a small concentration of viable
pathogens could potentially reach crops and become part of the food chain. Plants harvested
for human consumption are assumed to be washed, cooked, and/or peeled as appropriate,
which would reduce the likelihood of pathogen ingestion. Exposure pathways associated with
uptake of microbes via food produced on the farm are excluded from further evaluation for
the management options and microbes specified below:
• Open burning, exposure pathways 8-9; prions only
• Burial, exposure pathway 5; all three microbes considered in the exposure assessment for
the natural disaster scenario
• Composting, exposure pathways 6-7; all three microbes considered in the exposure
assessment for the natural disaster scenario
Exposure pathways in Table 6.1.2 and indicated by endnote "c" in are assumed to be
adequately controlled by existing pollution technologies (particularly for releases to water).
In addition, workers should be protected by use of PPE.
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
Exposure pathways for the off-site management options are not discussed in Sections 3 and 4
because, as explained in Section 2.2, releases to the environment from those options are from
pollution control systems that are assumed to operate within permitted levels. Controlled
emissions include releases to air and water. Residues on plant surfaces must meet tolerance
requirements. Management options, exposure pathways, and microbial hazards excluded
from further analysis are listed below:
• Off-site landfilling, exposure pathways 1-2; all three pathogens considered for the
natural disaster scenario
• Rendering, exposure pathways 1-2; all three pathogens considered for the natural
disaster scenario
As described in Section 3.1.1, this assessment assumes that recommended PPE includes
gloves and a dust mask and that PPE will be used by workers involved in the handling,
storage, and transportation of livestock carcasses prior to their disposal. Use of PPE mitigates
exposure to microbes for some of the exposure pathways identified in Table 6.1.2:
• Carcass handling, exposure pathways 1 - 3; all three pathogens considered for the natural
disaster scenario
• Temporary carcass storage, exposure Pathway 1; all three pathogens considered for the
natural disaster scenario
1.2, Estimated Human Ingestion Exposures
The only ingestion source included in the microbial exposure assessment is drinking water pulled
from an on-site groundwater well. Drinking water ingestion exposures were estimated for
microbes from temporary carcass storage, the on-site unlined burial, and on-site open burning
carcass management options. For the first two activities, microbes can be released to the soil and
then move with percolating water during precipitation events toward groundwater or move with
leachate from carcasses toward groundwater. Microbes that survive open burning and are buried
with the bottom ash also can move toward groundwater during precipitation events.
As noted in Table 2.4.4, there are a wide range of microbes associated with temporary carcass
storage and on-site unlined burial. For the temporary carcass storage pile, approximately 10 tons
of carcasses are placed in contact with bare earth where decomposition begins. During the burial
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
process, those same carcasses are transferred to an unlined pit, where decomposition continues.
As part of the decomposition processes, bodily fluids are released as leachate. All of the
microbes listed in Table 2.4.4 (e.g., viruses, bacteria, protozoa, and prions) could remain viable
in these fluids. The presence of extensive microbial contamination of subsurface soil surrounding
cattle decomposition pits and burial sites is supported by published microbial analyses of these
sites (Davies and Wray 1996; Joung et al. 2013). Davies and Wray (1996) placed two calves'
carcasses in a deep burial pit and two calves' carcasses in a decomposition pit, each measuring
2.5 m in depth. During pit construction, sampling pipes were inserted in the soil, with two pipes
adjacent to the carcasses within the pit and with the remainder in surrounding soils radiating
away from the carcasses at distances of 2 cm to 3 m. For each pit (10 sampling pipes per pit),
swabs were placed in the pipes and removed one week later. Swab samples were collected before
the calves' carcasses were placed in the pit and then weekly for two years after. Salmonella
typhimurium, C. perfringens, and Bacillus cereus (a potential surrogate for B. anthracis) were
isolated from these samples (Davies and Wray 1996). Pathogens released to soil could enter
groundwater with leachate from the carcass storage pile or buried carcasses. Joung et al. (2013)
collected groundwater samples from 1,200 sites following the mass burial of livestock carcasses
(e.g., cattle, swine, and poultry) after outbreaks of foot and mouth disease and highly pathogenic
avian influenza. The samples were collected within a 0-200 m radius from the burial site; the
depth of sample collection was not specified. C. perfringens, Salmonella spp., and Shigella spp.
were all isolated from these samples (Joung et al. 2013).
As stated in earlier sections, focus on three microbes (prions, B. anthracis, and E. coli 0157:H7)
facilitates this analysis. Their presence is considered when evaluating groundwater ingestion
associated with temporary carcass storage, with unlined burial, and with burial of ash from open
burning. For the composting option, E. coli 0157:H7 are expected to be inactivated; therefore,
exposure by drinking the groundwater would not occur. Table 2.4.4 illustrates the survival of
thermally-resistant pathogens, including prions and bacterial spores. Review of the available
literature, however, did not reveal quantitative data on the concentration of those pathogens in
leachate from decomposing livestock.
The on-site combustion-based livestock carcass management options yield ash, which is buried
on-site. Although the combustion processes are expected to inactivate and/or destroy most
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pathogens, viable prions could remain in buried ash from open-burning. Review of the available
literature did not reveal any data by which to estimate the concentration of prions in ash or the
possible reduction in viable prion concentration that might be associated with open burning. This
represents a significant data gap in evaluating this pathway.
Modeling the processes that influence fate and transport of microbes in groundwater is complex.
Considerations include (1) the reduction in pathogen populations in both soil and water when
there are no available hosts, (2) the ability of the organisms to survive as saprophytes or acquire
nutrients from dissolved organic matter, (3) characteristics of the microbes and soils that affect
sorption of microbes to soil particles, (4) the porosity of various soil types, and (5) the potential
presence of channels created by plant roots or freeze and thaw cycles. In the absence of
established models, this assessment uses a multi-step approach to estimate the concentration of
the three selected microbes (i.e., prions, B. anthracis, and E. coli 0157:H7) in groundwater and
to estimate human ingestion of these agents via drinking water from a well. As part of this
approach, it is assumed that there will be no re-growth of the agent in either soil or groundwater
prior to exposure.
To quantify exposure, this assessment uses information on four parameters for prions, B.
anthracis, and is. coli 0157:H7 (see Table 6.1.1):
1 Initial loading concentrations of prions, B. anthracis, and E. coli 0157:H7 in cattle
carcasses
¦ Concentrations of prions, B. anthracis, and E. coli 0157:H7 in leachate and/or ash from
cattle carcasses
¦ Fate of viable prions, spores of B. anthracis, and E. coli 0157:H7 cells in both soil and
water
¦ Vertical fate and transport efficiency17 for microbes in soil
Prions are expected to be hardiest of the microbes identified as potential hazards. They have a
small diameter, are resistant to heat and other environmental stressors, and have been shown to
survive for long periods of time in multiple media compartments (Miles et al. 2011; Smith et al.
17 Vertical fate and transport refers to the vertical migration of microbes as they travel vertically (down) from a source (in this
case carcasses) through the soil.
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
2011). Smith et al. (2011) reviewed the fate and transport of prions in soil and concluded that
prion attachment to soil particle surfaces protects them from enzymatic, chemical, or physical
degradation. While some soil types can serve as an environmental reservoir for prions for up to
three years, mobility in soil is limited (Miller et al. 2004; Smith et al. 2011). Moreover, soil-
bound prions are less bioavailable when ingested than free-prion particles. It is plausible that
prions released to the soil from buried ash could move toward groundwater (Miller et al. 2004;
Smith et al. 2011). Miles et al. (2011) evaluated the fate of prions in water. They reported an
approximate 90% reduction of infectious prions at 25°C, 37°C, and 50°C (ranging between 0.5-
logio and 1.4-logio) in one week, with continued reductions over eight subsequent weeks. In the
study, higher organic matter in the soil protected prions, allowing them to remain infectious for a
longer period of time. Nevertheless, there was a significant reduction in the number of viable
prions, and few might be viable by the time they reach groundwater. For the purpose of this
assessment, prions are assumed to survive, but are filtered out by soil particles, resulting in few
prions that reach groundwater.
In the absence of quantitative data, the starting concentration of microbes in carcasses is assumed
to be less than the infectious dose of the microbe associated with their respective illness(es). This
assumption applies to all the pertinent pathway assessments. As reported in Table 6.1.1, the
populations of all three representative pathogens decrease over time in soil and water without the
presence of hosts. This means the concentration of each microbe decreases after the initial
release from the decomposing carcass or ash, during the microbe's movement through the soil
toward groundwater, and between the transfer of the microbe from the groundwater source to the
drinking water well. Estimates of the concentration of each microbe ingested via drinking water
from the groundwater well are limited by the assumptions required to develop a starting
concentration for the agent in the carcasses and in the groundwater following the agents'
transport through the soil. Viable pathogen cells (e.g., E. coli 0157:H7) are likely to decrease in
groundwater over time if they cannot survive through dormancy (e.g., as a spore), as a saprobe,
or otherwise take up nutrients from the environment. Pathogen concentrations in groundwater are
estimated by multiplying the concentration of each microbe in soil by a vertical fate and
transport efficiency factor which accounts for physical loss during downward migration in soil.
The major loss process is straining or filtration by soil particles (Bitton and Gerba 1984; Yates et
al. 1988). Quantifying vertical transport for microbes is challenging because it depends on soil
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properties and weather conditions, including precipitation, which vary substantially. Yates et al.
(1988) reported bacterial migration in various types of subsurface materials and provided vertical
fate and transport efficiency values for E. coli 0157:H7 based on a variety of considerations,
including temperature, microbial activity, soil type, soil moisture content, pH, organic matter,
conductivity, and hydraulic condition among others. The authors reported a maximum travel
distance for E. coli 0157:H7 of 4 m and assumed a vertical fate and transport efficiency of
0.01(Yates et al. 1988, Table 6). That means that if the density of E. coli 0157:H7 in soil is equal
to 100 organisms per m3, then only 1 E. coli 0157:H7 cell per m3 reaches groundwater.
Table 6.2.1. Quantitative Assumptions for the Groundwater Exposure Pathway for
Microbes
Pathogen
Estimated Initial Loading
Concentration
(organisms/m3)
Decay
Rate
(hour 1)
Reference
Prions (PrPSc)
5.50E-03
6.90E-03
Yamamoto et al. (2006); Based on 0.5
logio in a week from Table 7.1 in
Miles et al. (2011)
Bacillus anthracis
5.50E+01
1.14E-04
Sinclair et al. (2008); WHO (2008)
Escherichia coli 0157:H7
1.25E+01
1.25E-03
Flip et al. (1988); Pepper et al. (2010)
The values provided in Table 6.2.1 are used to calculate the concentration of each respective
microbe in groundwater using the following equation:
CaBentll„UIU,w„,rm = Cagentsoi, (t) X EX xt Eq„
where:
Cagentgroundwater (0 = Pathogen groundwater concentration at time l (particles/m3)
Cagent_soii (0 = Pathogen soil concentration at time l (particles/m3)
Ef [vertical = Pathogen vertical fate and transport efficiency
(m3 soil/m3 groundwater)
decayjwater Agent decay rate in soil pore water (hr-1)
t time (hr)
The equation includes loss of viability (rate of decay over time) and assumes that there will be no
re-growth of the agent in either soil or groundwater prior to humans ingesting the well water.
The above equation calculates the density of prions, B. anthracis, and E. coli 0157:H7 in
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groundwater over time (initial concentration through 1 year), and the results are in Table 6.2.2
for each pathogen.
Table 6.2.2. Concentration of Pathogens in Groundwater over Time (particles/m3)
Pathogen
Initial
1 hr
24 hr
72 hr
1 week
4 weeks
3 months
6 months
1 year
Prions
(Prpsc)
1.21E-01
1.21E-01
1.03E-01
7.39E-02
3.81E-02
1.18E-03
4.09E-08
1.38E-14
1.56E-27
Bacillus
1.21E+0
1.21E+0
1.21E+0
1.20E+0
1.19E+0
1.13E+0
9.49E+0
7.42E+0
4.54E+0
anthracis
3
3
3
3
3
3
2
2
2
Escherichi
a coli
1.25E+0
0
1.25E+0
0
1.16E+0
0
9.99E-01
7.40E-01
1.54E-01
1.48E-03
1.75E-06
2.45E-12
0157:H7
Abbreviations: hr = hour.
As illustrated in Table 6.2.2, the concentration of each evaluated pathogen decreases over time.
For E. coli 0157:H7 and prions, the initial concentrations themselves are less than 1 particle per
m3, which is equivalent to less than 1 particle per 1,000 L or 1,000,000 mL. The initial
concentration of B. cmthrcicis was the highest and the loss of infectivity over time was the
smallest.
The presence of even small concentrations of pathogens in groundwater sources used for
drinking water presents a serious concern. USEPA regulates public water systems, and does not
have the authority to regulate private drinking water wells serving less than 25 users. Although
USEPA sets maximum contaminant levels (MCLs) for public water systems serving more than
25 users under the Safe Drinking Water Act (SDWA), the MCLs do not apply to public water
systems with fewer than 25 users or to private wells. As part of the implementation of the
SDWA, USEPA protects groundwater sources used for drinking water through implementation
of the Ground Water Rule and requires monitoring of groundwater sources under the Revised
Total Coliform Rule (RTCR). The RTCR establishes MCLs for total coliforms and E. coli
(USEPA 2013c). If routine monitoring results in a sample positive for total coliforms, then the
sample must be tested for E. coli. If the sample is positive for E. coli, and the MCL has been
exceeded, additional site assessment is required. Therefore, corrective action is required if any
samples test positive for E. coli (USEPA 2013c). Similar regulations are not explicitly available
for B. cmthrcicis or prions, but the MCL values for other regulated pathogens are zero.
For the purpose of making comparisons in this assessment, any detection of E. coli in the
groundwater well would be considered problematic for a drinking water source, private or
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public. Private wells are sampled for bacterial contamination less frequently public water
systems regulated by the SDWA. Private drinking water wells might continue to be used even if
pathogens are present in groundwater at detectable concentrations (USEPA 2014a). If the
pathogens were detected during water quality monitoring efforts, corrective action would be
needed before users could drink from the well. Like E. coli, the presence of any quantifiable
level of B. anthracis or prions in drinking water sources also indicates danger to human health,
even though enumeration of these pathogens is not part of routine water quality monitoring
efforts.
Whether or not a groundwater monitoring sample yields a positive result depends on the limit of
detection for the analysis method. Water quality assays typically used to detect E. coli in
groundwater include multiple tube fermentation, membrane filtration, and enzyme substrate
based-assays (California WRCB 2016). For example, USEPA Method 1604 (Total Coliforms
and Escherichia coli in Water by Membrane Filtration Using a Simultaneous Detection
Technique (MI Medium)) has a detection limit of 1 E. coli and/or 1 total coliform per 100 mL
sample volume. The concentrations of E. coli estimated in Table 6.2.2 are reported as particles,
not as the total number of organisms. It is possible that one particle could contain more than one
organism and that the concentration of particles detected by this method would underestimate the
concentration of individual E. coli cells. Therefore, it is unclear if all of the concentrations of E.
coli estimated in Table 6.2.2 fall below the limit of detection for common E. coli detection
assays. However, even if a groundwater sample tests negative for E. coli, particularly virulent
strains of E. coli could still pose a risk of illness in humans drinking the well water.
The principal described above for E. coli would also apply for prions, for which estimated
concentrations in groundwater are also below 1 prion per 100 mL sample. Even if samples tested
negative for prions, they could still be present in groundwater at lower concentrations than could
be detected and pose a risk of illness in humans drinking the groundwater.
The estimated concentrations of B. anthracis are greater than 1 colony forming unit (CFU) per
liter water sampled at all time intervals. Although groundwater samples are not routinely tested
for the presence of B. anthracis, culture-based assays have reported a limit of detection of 1 CFU
per L of water sampled (Herzog et al. 2009). Therefore, groundwater samples from the on-site
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well could yield positive results for B. anthracis if managed cattle were infected but
asymptomatic.
1.2.1. Estimated Ingestion
Using the concentration data in Table 6.2.2, Equation 6.2 estimates the ingested dose of each of
the three pathogens from drinking water from a groundwater well:
D°seagentgroundwater(t) = ^agentgroundwater(t) x ^ing_human_groundwater Eqn. 6.2
where:
Doseagentsoil(t) Pathogen exposure dose from groundwater ingestion (particles
/day)
Cagent_soii (0 Pathogen soil concentration over time (particles/m3)
Ving human groundwater Human daily groundwater ingestion rate (m3/day/person)
The groundwater ingestion rate and the adult body weight are reported in the USEPA Exposure
Factors Handbook (2011) as 42 mL/kg day and 80 kg, respectively. The results of this analysis
are presented in Table 6.2.3. The estimated ingestion of microbes from a groundwater well is
calculated as higher for B. anthracis than for is. coli 0157:H7 or prions.
Table 6.2.3. Estimated Human Ingestion of Microbes from a Groundwater Well
(particles/time interval)
Pathogen
Initial
1 hr
24 hr
72 hr
1 week
4 weeks
3 months
6 months
1 year
Prions
(Prpsc)
4.08E-04
4.05E-04
3.46E-04
2.48E-04
1.28E-04
3.95E-06
1.37E-10
4.63E-17
5.25E-30
Bacillus
anthracis
4.08E+00
4.08E+00
4.07E+00
4.05E+00
4.00E+00
3.78E+00
3.19E+00
2.49E+00
1.52E+00
Escherichia
coli
4.20E-03
4.19E-03
3.90E-03
3.35E-03
2.49E-03
5.16E-04
4.97E-06
5.88E-09
8.24E-15
0157:H7
Abbreviations: hr = hour.
The values presented in Table 6.2.3 are very conservative because the concentrations for each
microbe presented in Table 6.2.2 are likely much higher than the likely concentrations reaching
groundwater. This analysis assumed the same concentrations for the microbial load expected to
reach groundwater sources used for drinking water ingestion and exposure for the storage pile,
on-site burial, and composting. As stated in Section 3, the analysis assumed the groundwater
well is 30.5 m downgradient from the carcass disposal site.
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Estimates of human ingestion for B. anthracis and E. coli 0157:H7 are below their reported ID50
values; therefore illness in farm residents is unlikely (see Table 6.1.1). For B. anthracis, the ID50
value is 3-4 orders of magnitude higher than the estimated ingested dose. For E. coli 0157:H7,
the ID50 value is 5-6 order of magnitude higher than the estimated ingested dose at initial
exposure. Particularly sensitive individuals, including children, the elderly, and
immunocompromised persons, might become ill (Percival and Williams 2014).
For prions, an ID50 value in humans is not available, but an ID50 value is available for cattle. The
initial estimated ingested dose in Table 6.2.3 is less than the ID50 value in cattle by one order of
magnitude. Illness in farm residents could occur if groundwater is ingested soon after the initial
prion release reaches groundwater and if the human ID50 values is close to the ID50 value for
cattle.
1,2,2, Conclusions
Estimated exposure to E. coli 0157:H7 and B. anthracis in drinking water would be below the
ID50 in humans. For prions, exposure in drinking water might be close to the ID50 for cattle. If the
ID50 for humans is similar to that of cattle, some farm residents might fall ill.
Microbial populations are expected to be highest in temporary carcass storage piles, and reduced
in buried or composted carcasses over time as the pathogens are shed from the carcasses and
their food supplies diminish.
Decreases in viable microbe concentrations should be most rapid during the initial stages of
carcass decomposition. Ultimately, there may be only survival forms (e.g., prions and spores) of
pathogens present at the collection and disposal sites. Air-curtain burning could inactivate even
survival forms. Based on the efficacy of the various carcass management options to kill these
pathogens, no pathogens are expected to be viable in buried ash from air-curtain burning, and
fewer pathogens would be present in buried ash from an open pyre (prions only) than in leachate
from untreated buried carcasses or composted carcasses. This means that drinking water
contaminated by leachate from buried or composted carcasses is likely have more microbial
contamination than water contaminated by leachate from buried ash.
In summary:
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* The concentration of pathogens in ash would be lower than the concentration of pathogens in
leachate from other carcass management options due to thermal inactivation of pathogens.
Only prions are likely to remain viable in ash from open burning while no pathogens are
expected to remain infectious in ash from air-curtain burning.
¦ The concentration of viable pathogens released to the soil in leachate from the storage pile
could be higher than the concentration of pathogens released to the soil in leachate from
carcass composting and on-site burial. Pathogen viability would be highest in the first two
days post mortality, when the carcasses are stored in a pile on bare ground. After that, the
infectivity of pathogens would decrease over time owing to several processes.
¦ Leachate from the temporary storage pile and buried carcasses would contain a broad range
of pathogens, whereas finished compost is likely to only contain spores of spore-forming
pathogens and prions. The composting process will develop populations of a wide variety of
non-pathogenic microbial flora.
¦ The potential for contamination of drinking water supplies would reflect the initial microbial
populations present in the carcasses as attenuated by the specific carcass management option
and over time.
6.2, Livestock and Environmental Exposures
This section discusses livestock and wildlife exposures to microbes. Both qualitative and
quantitative approaches assess exposure of livestock and wildlife to microbes. In general,
exposure of livestock and wildlife is considered negligible due to source conditions and
microbial properties. However, livestock exposure to microbes following the ingestion of
contaminated groundwater was plausible. This potential exposure was quantified for one
transportation and handling activity, and two management options in Section 6.3.1. Some species
of wildlife might be exposed directly by ingesting parts of carcasses in the temporary storage pile
or via other pathways, as discussed in Section 6.3.2.
1,2,1, Livestock Exposure
Livestock on the farm might be exposed to microbes released to the environment during the on-
site management options via several pathways, as summarized in Table 6.3.1. Pathways include
exposure through inhalation, incidental soil ingestion while grazing, ingestion of drinking water
provided from an on-site groundwater well, and ingestion of plants grown on site, including
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grains, silage, and forage. All of these pathways are in common with human exposure pathways,
except that humans and livestock consume different plant products, and incidental soil ingestion.
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Table 6.3.1. Livestock Exposure Pathways for Livestock Carcass Management Options - Microbes
Exposure
Exposure Pathways Transportation and Handling
Activities
Exposure Pathways
Management Options
Source
Carcass
Handling
Temporary
Carcass Storage
Carcass
Transportation
Open Burning
Burial
Composting
Air Curtain
Burning
Inhalation
1) Air^
1) Air->
1) Air->
1) Air^
1) Air^
Livestock13
Livestock13
Livestock13
Livestock13
Livestock13
Incidental Soil
Ingestion
2) Air —> Soil—>
Livestock13
2) Air —> Soil—>
Livestock13
—
2) Air —> Soil—>
Livestock13
—
—
—
Groundwater
3) Leachate —>
3) Ash -> GW
2) Leachate —>
2) Leachate —>
Ingestion
GW —>
Livestock3
—
—> Livestock3
GW —>
Livestock3
GW —>
Livestock3
Ingestion of
Food Produced
3) Air —> Plants
—> Livestock13
4) Air —> Plants
—> Livestock13
4) Air —> Plants
—> Livestock13
3) Air —> Plants
—> Livestock13
3) Air —> Plants
—> Livestock13
on the Farm
4) Air —> Soil —>
5) Air —> Soil —>
—
5) Air —> Soil —>
4) Air —> Soil —>
4) Air —> Soil —>
Plants —>
Plants —>
Plants —>
Plants —>
Plants —>
Livestock13
Livestock13
Livestock13
Livestock13
Livestock13
Abbreviations: "—" = No exposure pathways; SW = surface water; GW = groundwater.
Note: Exposure pathways shown in bold were included in the quantitative exposure assessment.
a Quantitative methods were available for exposure assessment; results are presented below in Section 6.3.1.
b Potential exposures were assumed to be negligible based on source conditions or microbial properties.
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by livestock while grazing, particularly by cattle, is a greater potential source of exposure than
incidental soil ingestion by humans (e.g., through hand-to-mouth contact).
Exposure pathways with quantified exposures are indicated with bold type and endnote "a." The
remaining pathways of livestock exposure, indicated by endnote "b" in Table 6.3.1, were
assumed to be negligible and not quantified for the following reasons:
¦ Thermal Inactivation - The burn temperature and duration of the on-site open burning
option inactivates the pathogens with the exception of prions. Similarly, the duration of the
high temperatures characteristic of the on-site composting option can inactivate or destroy
many microbes, except for prions or spores from spore-forming bacteria (e.g., B. anthracis).
Because of the impact of temperature on the survival of microbes, many exposure pathways
that were assessed for chemicals were not evaluated for microbes. Air-curtain burning is not
included in Table 6.3.1 because the usual burn temperatures of this option is likely to
completely inactivate all three categories of pathogens included in the natural disaster
scenario.
¦ Inhalation - Microbes could be released to air during carcass transportation and handling
activities (i.e., carcass handling and temporary carcass storage) and several management
options (i.e., on-site open burning, burial, and composting). However, the probability of
direct inhalation by cattle is low, as it is for humans (see Section 6.1). Similar reasoning can
be applied to the assessment of livestock exposure. Livestock are assumed to be at least 30.5
m from the on-site open burning pyre, burial pit, composting pile, and temporary storage pile.
Microbial populations decrease with increasing distance from the site of livestock carcasses
and over time. Farm livestock are expected to be excluded from the area around the
temporary carcass storage pile and consequently not exposed to microbial populations in that
area. Microbes survive being buried or composted; however, livestock downwind of burial or
composting activities are likely to inhale few or no pathogens. During the composting
process, microbes in leachate from the carcasses are adsorbed to the underlying woodchips
and soil, and are not expected to be released to air. Similarly, microbes in leachate from a
burial pile are not expected to become aerosolized. Releases to air from windrow turning are
not evaluated because windrows for cattle composting are not turned.
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* Incidental soil ingestion - Aerosolized microbes could be deposited onto soil during (1) all
carcass handling activities, (2) temporary carcass storage, and (3) on-site open burning
processes (assumed to be for a 48-hr duration). However, many bacterial cells become
desiccated in air, which could kill the population in air (see Table 6.1.1). Livestock often
accidentally ingest soil during grazing. The number of microbes deposited downwind onto
soil or plant matter after open-burning carcass management activities is unknown. Given the
low number of viable microbes expected to be deposited on soil or plant matter, this exposure
pathway is assumed to be negligible for livestock as it is for humans.
* Ingestion of contaminated feed produced on the farm - Low initial microbial populations,
the relatively short time-frame for source emissions, and low likelihood that grazing pastures
would be directly downwind of carcass management activities, suggest livestock exposure
through their feed is unlikely. The impact of microbial aerosol emissions (the highest
deposition is over a limited area - within 600 m from the source in the direction of prevailing
winds based on AERMOD particulate dispersion modeling) - also suggests exposure via this
pathway is unlikely. For these reasons, the exposure of livestock to microbial contaminants
in their feed is considered to be negligible.
The food chain on the farm also includes pathways with livestock drinking groundwater (i.e.,
well water) containing prions that leached from buried combustion ash, and microbes in leachate
from buried carcasses or the temporary carcass storage pile. Watering of surviving livestock
using groundwater from the well will continue during the following carcass management stages:
temporary carcass storage, on-site open burning, on-site unlined burial, and composting. The
temperatures reached during the composting process are expected to inactivate most pathogens
with the exception of prions and spores of B. anthracis.
Exposures of livestock that drink water supplied by a groundwater well on the hypothetical farm
are quantitatively assessed below using a step-wise approach similar to that used to estimate
human exposure to microbes via drinking water ingestion. Data to differentiate the
transportation and handling activities and management options are not available, so the same
starting concentration for each of the microbes was used for all of the transportation and
handling activities and management options where exposure is possible. The concentration of
microbes ingested by livestock was assumed to be similar to the concentration that reached
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humans as described above in Section 6.2.1; however, the ingestion rates differ for humans and
cattle. Dairy cattle drink more water than beef cattle (Agriculture and Agri-Food Canada
undated):
¦ Dairy cattle: 95 L/day (summer), 77 L/day (winter); and
1 Beef cattle: 86 L/day (summer), 55 L/day (winter).
Quantitative estimates of dairy and beef cattle ingestion of water supplied by a groundwater well
are calculated for prions, B. anthracis, and E. coli 0157:H7. Equation 6.3 estimates cattle
ingestion of pathogens with well water:
An^ma^Doseagentgroundwater(f) = ^agentgroundwater(0 x Ving_animal_groundwater Eqn. 6.3
where:
AnimalDoseagent d t (0 Pathogen exposure dose for dairy and beef cattle from
groundwater ingestion at time t (organisms/day)
Cagent_soii (0 Agent soil concentration at time t (particles/m3)
Ving_animaigroundwater Cattle daily groundwater ingestion volume (m3/animal/day)
Table 6.3.2 presents the estimated ingestion of prions, B. anthracis, and is. coli 0157:H7 by
dairy cattle drinking water supplied by a groundwater well in both the summer and winter
seasons.
Table 6.3.3 presents the estimated ingestion of prions, B. anthracis spores, and E. coli 0157:H7
by beef cattle drinking water supplied by a groundwater well in both the summer and winter
seasons. Based on the results presented in Table 6.3.2 and Table 6.3.3, the estimated ingestion of
B. anthracis is expected to be higher than the ingestion of prions or E. coli 0157:H7 for both
dairy and beef cattle in both summer and winter seasons. The initial estimated ingestion of
microbes from a groundwater well is higher for prions, E. coli, and B. anthracis in humans
compared with cattle.
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Table 6.3.2 Estimated Ingestion of Microbes from a Groundwater Well - Dairy Cattle
(particles/time interval)
Agent
Season
Initial
1 hr
24 hr
72 hr
1 week
4 weeks
3 months
6 months
1 year
Prions
Summer
1.15E-02
1.15E-02
9.78E-03
7.02E-03
3.62E-03
1.12E-04
3.89E-09
1.31E-15
1.48E-28
(Prpsc)
Winter
9.35E-03
9.29E-03
7.92E-03
5.69E-03
2.93E-03
9.06E-05
3.15E-09
1.06E-15
1.20E-28
Bacillus
Summer
1.15E+02
1.15E+02
1.15E+02
1.14E+02
1.13E+02
1.07E+02
9.02E+01
7.05E+01
4.31E+01
anthracis
Winter
9.35E+01
9.35E+01
9.33E+01
9.28E+01
9.17E+01
8.66E+01
7.31E+01
5.72E+01
3.49E+01
Escherichia
coli
0157:H7
Summer
1.19E-01
1.18E-01
1.10E-01
9.49E-02
7.03E-02
1.46E-02
1.41E-04
1.66E-07
2.33E-13
Winter
9.63E-02
9.60E-02
8.93E-02
7.69E-02
5.70E-02
1.18E-02
1.14E-04
1.35E-07
1.89E-13
Abbreviations: hr = hour.
Table 6.3.3 Estimated Ingestion of Microbes from a Groundwater Well - Beef Cattle
(particles/time interval)
Agent
Season
Initial
1 hr
24 hr
72 hr
1 week
4 weeks
3 months
6 months
1 year
Prions
Summer
1.04E-02
1.04E-02
8.85E-03
6.36E-03
3.28E-03
1.01E-04
3.52E-09
1.18E-15
1.34E-28
(Prpsc)
Winter
6.68E-03
6.63E-03
5.66E-03
4.06E-03
2.10E-03
6.47E-05
2.25E-09
7.57E-16
8.59E-29
Bacillus
Summer
1.04E+02
1.04E+02
1.04E+02
1.04E+02
1.02E+02
9.68E+01
8.17E+01
6.38E+01
3.90E+01
anthracis
Winter
6.68E+01
6.68E+01
6.66E+01
6.63E+01
6.55E+01
6.19E+01
5.22E+01
4.08E+01
2.49E+01
Escherichia
coli
0157:H7
Summer
1.08E-01
1.07E-01
9.97E-02
8.59E-02
6.36E-02
1.32E-02
1.27E-04
1.51E-07
2.11E-13
Winter
6.88E-02
6.85E-02
6.38E-02
5.49E-02
4.07E-02
8.45E-03
8.14E-05
9.63E-08
1.35E-13
Abbreviations: hr = hour.
Available ID50 values for cattle for B. anthracis, prions, and coli 0157:H7 are presented in
Table 6.1.1. Estimates of ingestion for E. coli 0157:H7 are below the reported ID50 value,
whereas estimates of ingestion for prions and B. anthracis are higher than the reported ID50
values at certain times and seasons. For E. coli 0157:H7, the ID50 value is 6 orders of magnitude
higher than the estimated ingested dose for dairy and beef cattle in both the summer and winter
months. However, for prions, the estimated ingestion is greater than the ID50 during the summer
months for both dairy and beef cattle. The estimated ingestion falls below the ID50 value for
prions from 1 to 24 hours following the initial release to groundwater. Ingestion of drinking
water 24 hours after release results in exposure to prions one order of magnitude below the ID50
value.
The estimated ingestion of B. anthracis in drinking water is greater than the ID50 value for dairy
and beef cattle in both summer and winter for all evaluated time points. B. anthracis has a fairly
low ID50 value (<10 spores) in cattle. Estimates of ingestion are calculated in Table 6.3.3 from
initial release to groundwater through one year after that release. Exposure to B. anthracis in
water provided to cattle could pose a threat to public health for at least one year following the
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
release of this pathogen to the groundwater. Thus, burial, composting, and allowing an
uncovered temporary storage pile on bare ground might pose risks of illness to cattle and to
humans from B. anthracis.
6,2,3, Wildlife Exposure
The organisms most susceptible to adverse health effects from the three microbes evaluated,
other than humans and livestock, would be vertebrate wildlife. For this assessment, only animals,
and not plants, should be susceptible to falling ill from microbes that are pathogenic in humans
and livestock and that originate in the carcasses of healthy livestock.
One principal pathway/route of exposure of wildlife (e.g., birds, mammals, reptiles) to microbes
in livestock carcasses that is not evaluated for humans and livestock would be ingestion of bits of
carcasses from the temporary storage pile. Scavenging wildlife (e.g., crows, ravens, gulls,
raccoons, rats) could ingest microbes with bits of carcass from an uncovered temporary storage
pile. The risks to wildlife from the storage pile, however, would be the same across all seven
carcass management options. Direct ingestion of microbes with pieces of carcasses, therefore, is
not evaluated further in Phase 1, livestock mortality following a natural disaster. This pathway is
assessed for Phase 2, mortality from livestock disease outbreak.
Other exposure pathways and routes to a variety of types of organisms are possible. Wildlife of
concern are:
¦ Wider-ranging animals that might frequent the affected property and feed on less mobile
animals (e.g., soil invertebrates, small rodents) and plants as food sources
¦ Benthic invertebrates within waters in a region and the fish that feed on them
For the purpose of this assessment, the hypothetical farm includes an on-site lake. The lake could
lead to exposures of several types of animals:
¦ Fish that feed on aquatic plants, planktonic organisms, benthic invertebrates, or smaller fish
¦ Semi-aquatic animals (e.g., amphibians, water birds, beavers, muskrat, and piscivorous
mammals such as mink)
¦ Terrestrial animals (e.g., soil-dwelling invertebrates, other insects, passerine birds that feed
on above or below-ground insects to provision their young, small mammals that feed on
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
seeds (e.g., mice) or on soil invertebrates (e.g., shrews), and larger grazing or predatory
mammals)
¦ Other organisms in soils (e.g., plants and soil microbes)
The assessment assumes that animals and their foods are not exposed to microbes from the three
off-site management options, because releases from off-site commercial facilities are regulated to
be within health-protective limits and to be environmentally responsible. The three off-site
carcass management options are commercial incineration, landfilling, and rendering. For
example, landfills should be covered with tarps to prevent excess infiltration by precipitation and
to prevent scavenging by animals (most notoriously gulls along the Great Lakes and east and
west coasts).
Exposure of wildlife might occur during transportation of carcasses to off-site carcass
management facilities from accidents with spills or from leaks. However, as described in Section
3.1.3, the likelihood of a vehicle accident with livestock carcasses spilled onto a road is very
remote. Leaks of leachate along the travel route might deposit viable microbes along the
roadway; ground-feeding wildlife might incidentally ingest the microbes and scavenging
mammals might be attracted by the smell. The chance of an animal ingesting an infectious dose,
however, is small. A total of 160 liters of leachate might leak from a truck during off-site
transportation of 50 tons of carcasses (8 trips with 20 L leaked per trip), but the leachate would
be spread over many miles of roadway. Additional wildlife exposure pathways are possible for
the following management options and potential microbial hazards:
¦ On-site open-burning - Prions could be released to air during the burn and buried with the
remaining ash after. Pathways to the on-site lake are the same as those identified in Sections
6.2 and 6.3.1.
¦ Composting - Prions and spores from spore-forming bacteria (i.e., B. anthracis,
Clostridium perjringens, and Coxiella burnetii) could reach the lake as described in Section
6.2.
¦ On-site unlined burial - All of the potential microbial hazards evaluated could be released
to subsurface soils; however, it is unlikely that microbes could reach the lake in sufficient
concentrations to reach wildlife at infectious doses (substantial soil filtering both vertical
and horizontal, dilutions along a food chain).
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
Further consideration of the frequency of accidents and the potential volume of leachate caused
by leaks or spills from carcass transportation vehicles (discussed in detail in Section 3.1.3)
indicate these activities would not cause exposure to ecological receptors. Consequently, the
combination of transport and off-site carcass management are not sources of exposure for
ecological receptors.
One key consideration in assessing ecological effects from exposures to microbes originating
with transportation and handling activities and on-site carcass management options is the
pathogen's host range. As listed in Table 2.4.4, a wide range of pathogenic microbes are
associated with the carcass management options listed above, including several groups of
bacteria, viruses, protozoa, and prions. Many of these microbes have complex host ranges where
multiple, unique strains that can produce infection in some hosts but are not infective in others.
Many of the microbes included in Table 2.4.4 produce zoonotic diseases, meaning they can
cause illness in animals and humans. For example, humans, cattle, sheep, goats, horses, pigs,
dogs, cats, and other mammalian wildlife can become infected with B. anthracis; however,
amphibians, reptiles, fish, and most birds are not directly susceptible to infection with B.
anthracis (Spickler 2007). Additionally, vultures and flies can disseminate B. anthracis
mechanically after feeding on carcasses (Spickler 2007). To adequately assess possible
ecological effects, the pathways for transmission among species and infectivity of each of the
microorganisms in Table 2.4.4 would need to be investigated.
Plants can be exposed to microbes in a variety of ways including direct deposition on foliage
followed by surface adhesion, uptake by the roots, and through irrigation with well water. It is
assumed that crops grown for human consumption are be washed, cooked, and/or peeled as
appropriate. These processes would remove or inactivate many of the microorganisms that may
have been deposited to the surface of any edible plants. However, foodborne outbreak research
indicates that some human pathogens can become internalized into plant tissues, which reduces
the effectiveness of conventional processing and chemical sanitizing methods in preventing
transmission from contaminated produce (Lynch et al. 2009). Foodborne illnesses are associated
with the following pathogens included in Table 2.4.4: norovirus, Clostridiumperfringens,
Cryptosporidium spp., Campylobacter spp., E. coli 0157:H7, Listeria monocytogenes,
Salmonella spp., Shigella spp., Yersinia enterocolitica, Giardia spp., Mycobacterium bovis
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
Toxoplasma gondii, and Vibrio spp. (Scallan et al. 2011). These potential microbial hazards are
associated with carcass handling, temporary carcass storage, and on-site unlined burial. It is
unclear if foodborne illnesses caused by these agents were due to human consumption of
internally contaminated plant materials, a failure to practice proper food handling practices, or a
combination of both possibilities. Wildlife that might feed on plants in the vicinity of carcass
handling and storage or carcass management sites could be exposed to pathogens incorporated
into the plants or simply deposited on the surfaces of foliage or grains as consumed by the
wildlife. Pathogens that cause illness in humans, livestock, and wildlife, however, are unlikely to
adversely affect plants owing to taxonomic distance and marked differences in physiology.
Similarly, the host ranges for the vast majority of plant pathogens do not include humans (USDA
2016).
Ecological receptors could be exposed to potential microbial hazards via the carcass handling,
temporary carcass storage, burial, on-site open burning, and composting management options.
Exposure to fewer microbes is expected for composting (i.e., prions and B. anthracis) and open
burning (i.e., prions) because these carcass management options kill or inactivate many
microbes. The specific number of ecological receptors impacted by each handling activity and
management option is unknown as is the frequency and duration of exposure. The expected
exposure concentration is unknown, but thought to be lower than the initial loading concentration
as some microbes die, while others adhere to soil particles. For these reasons, it is unclear what
concentration of microbes would reach a given ecological receptor.
In summary, the highest potential for exposure to a higher number of microbes is associated with
the following:
1 Temporary on-site carcass storage
¦ On-site unlined burial
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
'\i 'iu>arative Risk; fav f uestoek Management Options
This section compares the livestock carcass management options relative to each other in a two-
tiered approach. Tier 1 (Section 7.1) groups the seven carcass management options in two
categories of potential exposure based on the level of regulatory pollution controls that limits
releases of chemicals and microbes to the environment. Tier 1 also considers the number of
potential exposure pathways identified in the conceptual models for each management option
(Appendix C) and describes why the three off-site carcass management options present minimal
to negligible relative risks. In Tier 2, the four on-site management options are evaluated further
based on the quantitative exposure assessments presented in Sections 3 through 6. Exposures are
normalized to inherent toxicity or infectious dose in Section 7.2, and results of the Tier 2
comparison are presented separately for chemicals (Section 7.2.1) and microbes (7.2.2). Sections
7.3 and 7.4 provide further information to help readers understand and use the findings of this
assessment. Section 7.3 discusses the uncertainties and limitations of the assessment, including
information about how different assumptions or site-specific circumstances could affect the
estimated exposures. Section 7.4 summarizes the livestock carcass management options,
potential exposure mitigation strategies, and research needs.
Readers of this document should recognize that the relative risks calculated for the hypothetical
site might differ from relative risks of the different carcass management options in specific
locations and under various conditions. This document does not replace the need for county or
statewide planning for natural disasters with mass livestock mortality based on availability of
off-site management options and suitability of on-site options for the region.
r 1 Comparison of the Seven Carcass Management Options
As discussed in Section 2, this assessment considers seven well-established carcass management
options with documented use following natural disasters or with sufficient capacity for large
scale carcass management. With the three off-site options, releases to the environment (e.g.,
incinerator emissions to air, rendering facility discharge to surface water) are restricted by, and
are assumed to comply with, applicable regulations. Therefore, chemical and microbial releases
from off-site commercial facilities are assumed to be adequately controlled. The on-site
management options all include uncontrolled or minimally controlled chemical and possibly
microbial releases to air, soil, or water, for which exposures are modeled as described in Sections
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
3 through 6. Moreover, the conceptual models (Appendix C) show that on-site management
options tend to have more potential exposure pathways than the off-site options, with the
possible exception of off-site transportation. Following a natural disaster, however, transport of
carcasses off-site is unlikely to result in hazardous environmental releases, because the
probability of an accident that dumps carcasses on a roadway is very small (see Section 3.1.3).
Acknowledging the distinction between off-site and on-site options based on regulatory pollution
control constitutes the first tier ranking of the seven carcass management options. Table 7.1.1
presents that ranking and lists the numbers of conceptual model pathways for chemicals and for
microbes. Table 7.1.1 also describes controlling legislation and technologies to limit releases to
permitted levels or below. The table shows that the three off-site options are ranked higher (i.e.,
less potential for exposure and risk) than the four on-site options based on these considerations.
Table 7.1.1. Tier 1 Ranking of Livestock Carcass Management Options
Tier 1 Ranking
Management
Options
Chemical
Exposure
Pathways
Microbial
Exposure
Pathways
Controls and Limits to Environmental
Releases
Rank 1:
Negligible to
minimal exposure —
releases regulated to
levels safe for human
health and the
enviromnent
Incineration
6
6
Air emissions regulated under the Clean
Air Act (CAA), including pollution
control equipment (e.g., scrubbers, filters),
with tall stacks to prevent localized
deposition; residuals (i.e., ash) managed
under the Resource Conservation and
Recovery Act (RCRA); wastewater
managed under the Clean Water Act
(CWA).
Rendering
3
2
Releases to air and to water regulated
under the CAA and CWA, respectively.
Landfilling
2
2
Landfill design and operation regulated
under RCRA; controls include leachate
collection and management and methane
recovery.
Rank 2:
Higher exposure
potential —
uncontained releases
to the enviromnent
Open
Burning
10
10
Uncontrolled and unregulated combustion
emissions; possible releases from
combustion ash if managed on site.
Air-curtain
Burning
10
10
Partially controlled but unregulated
combustion emissions, possible releases
from combustion ash if managed on site.
Composting
8
7
Partially controlled releases from compost
windrow (minor leaching, runoff, and gas
release to air); where finished compost is
tilled into soils, potential runoff and
erosion from amended soil.
Burial
6
6
Uncontrolled leaching from unlined
burial; slow gas release to air.
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7.2, Tier 2 Ranking of On-site Carcass Management Options
In Tier 2, the four on-site carcass management options are compared based on estimates of
chemical (Section 7.2.1) and microbial (Section 7.2.2) exposures normalized to inherent toxicity
and infectious dose, respectively.
1,2,1, Tier 2 Ranking Based on Chemical. Exposures
For chemicals, the Tier 2 ranking of the four on-site carcass management options uses the
chemical exposure estimates presented in Section 5. As discussed previously, chemical
exposures are not estimated for all of the exposure pathways in the conceptual models. The
pathways for which chemical exposures were quantified are shown in bold type in Table 5.1.1.
For convenience, Table 5.1.1 is repeated here in Table 7.2.1. The exposure pathways that were
not quantified for one or more reasons are included in Table 7.2.1 in plain (not bold) type. The
reasons that certain pathways were not assessed were discussed in Section 5.1.
Although each of the on-site management options includes preceding carcass transportation and
handling steps, Table 7.2.1 shows that chemical exposures associated with those steps are
evaluated in Tier 2 separately from the management options themselves. That allows one to
distinguish their contribution to the overall chemical exposures. The on-site carcass
transportation and handling steps, and their resulting chemical exposures, are assumed to be the
same for all seven management options, and therefore do not need to be included for comparison
of the four on-site management options.
By itself, an exposure concentration does not indicate whether adverse effects on human health
or environmental quality are possible or likely. To support a risk-based comparison of the
exposure estimates, they are normalized to inherent toxicity using toxicity reference values
(TRVs). A TRV is a concentration- or dose-based estimate of the exposure level below which
adverse health effects are not expected for individual humans in the population evaluated. TRVs
are chemical-specific and are developed by various agencies (e.g., USEPA, ATSDR) using
agency- or program specific-methods and definitions. TRVs also are developed for various
exposure durations. For example, the USEPA NHSRC established Provisional Advisory Levels
(PALs) for both inhalation and oral exposures in the event of an accidental or deliberate release
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Table 7.2.1. Human Exposure Pathways for Livestock Carcass Management - Chemicals
Carcass Transportation and Handling
Carcass Management Options
Exposure Source
Carcass
Handling
Temporary Carcass
Storage
Carcass
Transportation
Open Burning and
Air curtain Burning
Burial
Composting
Inhalation
1) Airb
1) Airb
1) Airb
1) Air3
1) Airb
1) Airb
2) Leachate —> GW —>
2) Ash —> GW —> In-
2) Leachate —>
2) Compost —> GW
In-home Aerosol0
home Aerosolb
GW —> In-home
Aerosolb
—> In-home Aerosolb
Incidental Ingestion
2) Hand-to-
mouth
ingestion b<°
—
2) Accident —>
soil1,0
3) Air —> soilb
—
—
Dermal
3) Direct
3) Accident —>
dermal contact0
soil0
Fish Ingestion
3) Leachate —> GW
—> SW —> Fish3
4) Air —> SW —> Fish3
5) Air —> soil —> SW
3) Leachate —>
GW —> SW —>
3) Compost —> soil
—> SW —> Fish3
—> Fish3
6) Ash —> GW —> SW
—> Fish3
Fish3
4) Compost —> GW
—> SW —> Fish3
Groundwater
4) Leachate —> GW3
7) Ash -> GW3
4) Leachate —>
5) Compost —>
Ingestion
GW3
GWa
Ingestion of Food
Produced on the
5) Air —>
Plants/livestock13
8) Air ->
Plants/livestock3
5) Air —> Plants/
Livestock13
6) Compost —> Soil
—> Plants/
Farm
6) Leachate —> GW —>
9) Air -> Soil ->
6) Leacliate —>
Livestock3
Livestock13
Plants/ Livestock3
GW —> Livestock13
7) Air —> Plants/
10) Ash —> GW —>
Livestock13
Livestock13
8) Compost —> soil
—> GW —>
Livestock13
Abbreviations: "—" = no exposure pathways; SW = surface water; GW = groundwater.
Exposure pathways shown in bold were included in the quantitative exposure assessment. Pathways were not quantitatively assessed for the following reasons:
a Quantitative methods were available for exposure assessment; Results are presented in Section 6.3.
b Potential exposures were assumed to be negligible based on source conditions or chemical properties.
c Environmental releases or exposures were assumed to be adequately controlled by existing pollution control regulations or use of personal protective equipment.
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
of chemicals to air or water over periods of 24 hours, 30 days, 90 days, or two years. The
chemicals for which USEPA PALs are available, however, are not among those evaluated for
carcass management options. USEPA and other agencies often prepare separate TRVs for acute,
subchronic, and chronic exposures (see Appendix L).
The TRVs used for this assessment are listed in the Oak Ridge National Laboratory's Risk
Assessment Information System (RAIS).18 In addition, TRVs differ for each chemical and each
route of exposure (i.e., oral or inhalation) and for cancer and non-cancer health effects. Preferred
TRVs are those most appropriate for the modeled exposure durations (e.g., 24-hr to 48-hr acute
inhalation benchmarks for inhalation exposures during a 48-hr on-site open or air-curtain burn)
and those developed by USEPA.
The available TRVs and those chosen for the assessment are documented in Appendix L. Non-
cancer effects associated with two-day inhalation exposures are normalized to (i.e., divided by)
acute (24-hr to 30-day) inhalation reference concentrations (RfCs) where available. As described
in Appendix L, RfCs derived for shorter exposure durations (e.g., 10, 30, or 60 minutes, or 8
hours) are not used because they would not necessarily be safe for a 48-hr exposure. None of the
chemicals assessed for the combustion-based management options have 24-hr inhalation criteria.
If acute inhalation RfCs are not available, a subchronic or chronic RfC is used, with preference
in that order. Because cancer benchmarks are based on increased cancer risk from a lifetime
exposure, cancer health effects are not evaluated for the single, 48-hr inhalation exposure during
on-site combustion events.
As discussed in Section 5.1.2, ingestion exposures are assumed to occur over the first year of
maximum exposures, with subsequent ingestion exposures declining over time as the chemical
mass at the carcass management location is depleted and less chemical mass is available to reach
exposure media. Moreover, chemicals in the environment become more dispersed over time.
Accordingly, the preferred TRVs for evaluating non-cancer health effects from ingestion
exposures are subchronic oral reference doses (RfDs), which are developed for periods up to 7
years (USEPA 1989). Chronic oral RfDs are selected when subchronic RfDs are unavailable. For
18 The Risk Assessment Information System is available at: https://rais.ornl.gov/
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
cancer health effects, oral slope factors are selected, when available, to normalize ingestion
exposures, as described in more detail below.
The selected TRVs are referred to by the general term "benchmarks," because they include
values for cancer and non-cancer endpoints, are developed by various agencies for various
exposure durations, and differ for inhalation and oral exposures. The benchmarks for inhalation
exposure are expressed as air concentrations, whereas the benchmarks for ingestion exposures
are expressed as the ingested dose (i.e., mg[chemical]/kg[human body weight] per day). As
described below, exposure estimates for each management option, chemical, and exposure route
are compared to the cancer and non-cancer benchmarks for purpose of comparing or ranking the
management options relative to one another.
Even in comparative or relative risk assessments, cancer and non-cancer endpoints are not
grouped into one category. There are no consensus guidelines at USEPA by which risk assessors
can combine estimates of cancer risk (a probability or incidence rate) with a hazard quotient
(ratio of a point estimate of exposure to the appropriate benchmark, either >1.0 indicating
adverse effect are possible or <1.0 indicating adverse effects are unlikely). Some health effects
upon which non-cancer toxicity RfCs or RfDs are based are more severe than others. Some types
of cancer are associated with limited expected future survival whereas others have better
prognoses.
For this relative risk ranking of the four on-site carcass management options, ratios of exposure
to benchmarks for non-cancer and cancer endpoints are calculated. Given the data limitations and
generic assumptions for this assessment, risk managers and the public should not interpret any
numeric results in this document as "actual likely" exposures (Section 5) or risks (this section).
The estimated exposures (Section 5) are compared with the relevant benchmarks by calculating
the ratios of exposure to benchmarks, as shown in Tables 7.2.2 through 7.2.11. These ratios are
referred to as "ranking ratios." For these calculations, only the exposures estimated for children 1
to <2 years of age are used, because that age group is more highly exposed (e.g., ingest more
food per unit body weight) than older children and adults. The first data column in each of these
tables presents the estimated magnitude of exposure for the young children. The next column for
inhalation tables presents the non-cancer inhalation (RfC) benchmarks, as documented in
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
Appendix L. For the ingestion tables, both cancer and non-cancer benchmarks, as documented in
Appendix L, are presented after the estimated ingested dose. The final columns present the
ratio(s) of the estimated exposure to the benchmark(s).
Table 7.2.2. Ingestion Exposure Assessment for Temporary (48-hr) Carcass Storage
Estimated
Benchmarks
Ranking Ratios
Chemical Species
Ingestion ADD
(mg/kg d)
RID
(mg/kg d)
RSD
(mg/kg d)
ADD/RfD
LADDa/RSD
Total Dioxins/furans
na
2.0E-08
7.7E-10
na
na
Total PAHs
na
nb
1.4E-05
na
na
Arsenic
na
3.0E-04
6.7E-05
na
na
Cadmium
na
1.0E-03
nc
na
na
Chromium
na
3.0E-03
nc
na
na
Copper
3.9E-12
1.0E-02
nc
3.9E-10
na
Iron
3.8E-09
7.0E-01
nc
5.4E-09
na
Lead
na
nb
1.2E-02
na
na
Manganese
4.7E-12
1.4E-01
nc
3.3E-11
na
Nickel
2.6E-12
1.1E-02
nc
2.3E-10
na
Zinc
2.4E-10
3.0E-01
nc
8.1E-10
na
Abbreviations: d = day; ADD = average daily dose; RiD = reference dose; RSD = risk-specific dose for carcinogenic chemicals
for a target risk of lE-04assuming ingestion of contaminated media occurs over a year of daily exposures; LADD = lifetime
average daily dose; PAH = polycyclic aromatic hydrocarbon; nb = benchmark (non-cancer) not available for oral exposure; na =
not assessed; nc = not considered carcinogenic by ingestion exposures.
Note: Ingestion sources include fish caught from the on-site lake and drinking water drawn from an on-site well.
a Cancer TRVs represent cancer risk over a lifetime of exposure. Therefore, average daily exposure dose for the first year (i.e.,
the ADD) is divided by 70 years to calculate the LADD.
For inhalation exposures (Tables 7.2.3 and 7.2.5), which are estimated only for the combustion-
based management options, both exposures and benchmarks are expressed as air concentrations
(|ig/m3). Dose-based ingestion exposures (i.e., remaining tables from 7.2.2 through 7.2.11) are in
units of mg/kg-day. Non-cancer TRVs used as benchmarks can be compared directly to the
estimated ingestion exposures, which are average daily doses (ADDs) for the first year of
maximum exposures following carcass management.
The cancer oral TRVs (oral slope factors) require a transformation for direct comparison to
exposure estimates. Oral slope factors are in units of per mg/kg-day (i.e., (mg/kg-day)"1). A
target risk level of 1E-04 is divided by the oral slope factor to calculate the corresponding risk-
specific dose (RSD), that is, the dose that corresponds to a target risk level of 1E-04 (one in
10,000) over a lifetime of exposure. This risk target is selected because, in general, USEPA
considers excess cancer risks above 1E-04 to be sufficiently large that some response action is
merited (USEPA 1991).
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
Table 7.2.3. Inhalation Exposure Assessment for the Open-burning Option
Chemical Species
Estimated Inhalation Exposure
Concentration (jig/m3)
Benchmarks, RfC
(jig/m3)
Ranking Ratios:
Exposure/RfC
Total Dioxins/furans
4.2E-10
4.0E-05
1.1E-05
Total PAHs
6.8E-02
nb
na
Arsenic
7.7E-04
1.5E-02
5.1E-02
Cadmium
1.4E-03
3.0E-02
4.7E-02
Chromium
1.2E-02
1.0E-01
1.2E-01
Copper
9.5E-03
1.0E+02
9.5E-05
Iron
3.1E+00
nb
na
Lead
1.3E-02
nb
na
Manganese
2.9E-02
5.0E-02
5.8E-01
Nickel
1.1E-02
6.0E-02
1.8E-01
Zinc
9.9E-02
nb
na
Abbreviations: RfC = reference concentration; PAH = polycyclic aromatic hydrocarbon; nb = no benchmark available for
inhalation exposure; na = not assessed.
Notes: Exposure duration is 48 hours. Cancer risk is not evaluated for this short-term exposure.
Table 7.2.4. Ingestion Exposure Assessment for the Open-burning Option
Estimated Benchmarks Ranking Ratios
Chemical Species
Ingestion ADD
(mg/kg d)
RI D (mg/kg d)
RSD (mg/kg
d)
ADD/RfD
LADDa/RSD
Total
Dioxins/furans
4.6E-11
2.0E-08
7.7E-10
2.3E-03
8.5E-04
Total PAHs
4.2E-06
nb
1.4E-05
na
4.3E-03
Arsenic
7.7E-07
3.0E-04
6.7E-05
2.6E-03
1.6E-04
Cadmium
9.4E-07
1.0E-03
nc
9.4E-04
na
Chromium
2.3E-04
3.0E-03
nc
7.7E-02
na
Copper
6.3E-05
1.0E-02
nc
6.3E-03
na
Iron
2.8E-02
7.0E-01
nc
4.0E-02
na
Lead
3.9E-07
nb
1.2E-02
na
4.6E-07
Manganese
2.4E-05
1.4E-01
nc
1.7E-04
na
Nickel
4.7E-06
1.1E-02
nc
4.3E-04
na
Zinc
4.1E-04
3.0E-01
nc
1.4E-03
na
Abbreviations: d = day; ADD = average daily dose; RiD = reference dose; RSD; risk-specific dose for target risk of 1.0E-04;
LADD = lifetime average daily dose; PAH = polycyclic aromatic hydrocarbon; nb = benchmark (non-cancer) not available for
oral exposure; na = not assessed; nc = not considered carcinogenic by ingestion exposures.
Notes: Ingestion sources include agricultural products grown on site, fish caught from the on-site lake, and drinking water drawn
from an on-site well.
a Cancer oral slope factors represent cancer risk over a lifetime of exposure. Therefore, average daily exposure dose for the first
or maximum year of exposure (i.e., the ADD) is divided by 70 years to calculate the LADD.
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
Table 7.2.5. Inhalation Exposure Assessment for the Air-curtain Burning Option
Inhalation Exposure
Benchmarks
Ranking Ratios
Chemical Species
Concentration
(Hg/m3)
RfC (jig/m3)
Exposure/RfC
Total Dioxins/furans
7.4E-08
4.0E-05
1.8E-03
Total PAHs
2.6E-04
nb
na
Arsenic
2.9E-04
1.5E-02
2.0E-02
Cadmium
2.0E-03
3.0E-02
6.6E-02
Chromium
9.3E-03
1.0E-01
9.3E-02
Copper
1.0E-02
1.0E+02
1.0E-04
Iron
5.7E-01
nb
na
Lead
9.3E-03
nb
na
Manganese
7.0E-01
5.0E-02
1.4E+01
Nickel
4.3E-03
6.0E-02
7.1E-02
Zinc
1.7E-01
nb
na
Abbreviations: RfC = reference concentration; PAH = polycyclic aromatic hydrocarbon; nb = no benchmark (non-cancer) for
inhalation exposure; na = not assessed.
Note: Exposure duration is 48 hours. Cancer risk is not evaluated for this short-term exposure.
Table 7.2.6. Ingestion Exposure Assessment for the Air-curtain Burning Option
Ingestion Benchmarks Ranking Ratios
Chemical Species
ADD
(mg/kg d)
Reference
Dose (mg/kg d)
Risk specific
Dose (mg/kg d)
ADD/RfD
LADDa/RSD
Total Dioxins/furans
6.8E-10
2.0E-08
7.7E-10
3.4E-02
1.3E-02
Total PAHs
8.0E-09
nb
1.4E-05
na
8.2E-06
Arsenic
2.4E-07
3.0E-04
6.7E-05
8.1E-04
5.1E-05
Cadmium
7.4E-07
1.0E-03
nb
7.4E-04
na
Chromium
7.6E-05
3.0E-03
nb
2.5E-02
na
Copper
3.1E-05
1.0E-02
nb
3.1E-03
na
Iron
2.0E-03
7.0E-01
nb
2.9E-03
na
Lead
1.5E-07
nb
1.2E-02
na
1.8E-07
Manganese
2.4E-04
1.4E-01
nb
1.7E-03
na
Nickel
9.2E-07
1.1E-02
nb
8.4E-05
na
Zinc
4.5E-04
3.0E-01
nb
1.5E-03
na
Abbreviations: d = day; ADD = average daily dose; RiD = reference dose; RSD; risk-specific dose for target risk of 1.0E-04;
LADD = lifetime average daily dose; PAH = polycyclic aromatic hydrocarbon; nb = benchmark (non-cancer) not available for
oral exposure; na = not assessed;
Notes: Ingestion sources include agricultural products grown on site, fish caught from the on-site lake, and drinking water drawn
from an on-site well.
a Cancer oral slope factors represent cancer risk over a lifetime of exposure. Therefore, average daily exposure dose for the first
or maximum year of exposure (i.e., the ADD) is divided by 70 years to calculate the LADD.
Because oral slope factors are developed to estimate the likelihood of cancer in a 70-yr lifetime,
the estimated exposure (i.e., ADD) for the first year or year of maximum exposure is divided by
70 years before calculating the ranking ratio for a chemical and management option. Although
ingestion exposures are likely to continue after the first year (or year of maximum exposure) for
174
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
Table 7.2.7. Ingestion Exposure Assessment for the Burial Option
Ingestion
Benchmarks
Ranking Ratios
Chemical Species
ADD
(mg/kg d)
Reference Dose
(mg/kg d)
Risk specific
Dose (mg/kg d)
ADD/RfD
LADDa/RSD
Total Dioxins/furans
na
2.0E-08
7.7E-10
na
na
Total PAHs
na
nb
1.4E-05
na
na
Arsenic
na
3.0E-04
6.7E-05
na
na
Cadmium
na
1.0E-03
nb
na
na
Chromium
na
3.0E-03
nb
na
na
Copper
6.3E-11
1.0E-02
nb
6.3E-09
na
Iron
1.4E-08
7.0E-01
nb
2.0E-08
na
Lead
na
nb
1.2E-02
na
na
Manganese
3.0E-11
1.4E-01
nb
2.2E-10
na
Nickel
5.0E-12
1.1E-02
nb
4.5E-10
na
Zinc
2.2E-09
3.0E-01
nb
7.4E-09
na
Abbreviations: d = day; ADD = average daily dose; RiD = reference dose; RSD = risk-specific dose for target risk of 1.0E-04;
LADD = lifetime average daily dose; PAH = polycyclic aromatic hydrocarbon; nb = no benchmark (non-cancer) available for
ingestion exposures; na = not assessed.
Note: Ingestion sources include fish caught from the on-site lake and drinking water drawn from an on-site well.
a Cancer oral slope factors represent cancer risk over a lifetime of exposure. Therefore, average daily exposure dose for the first
or maximum year of exposure (i.e., the ADD) is divided by 70 years to calculate the LADD.
some pathways, the decline in exposure over subsequent years should be exponential, with the
continuing depletion of chemical mass at the source and dispersion in the environment. With
annual declines of chemical mass at the source ranging from 0.01 to 0.99 of the mass from the
preceding year, the likely lifetime ADD (i.e., LADD) might exceed the maximum one-year ADD
by up to a factor of 2 (i.e., for a 0.5 annual decline) at most. Loss rates of 0.1 and 0.9 per year
would yield a LADD only 1.1 times the ADD. Given the uncertainty associated with estimating
the decline in exposure over subsequent years, for purposes of ranking relative risks, each LADD
is assumed to equal its one-year ADD. Ranking ratios for cancer health effects are estimated by
dividing the LADDs by the RSDs.
The composting management option includes two distinct sets of activities that take place at
different on-site locations and times: composting carcasses in the windrow and application of the
finished compost to a portion of the farm. Findings for both of these activities combined are
shown in Table 7.2.8, and findings for the compost windrow only and compost application only
are shown in Tables 7.2.9 and 7.2.10, respectively. Evaluating the contributions of the
composting phase and application of the finished compost shows that overall exposures for this
management option appear to be driven by application of the finished compost. One reason for
this is that chemical releases to groundwater from the windrow are largely contained by the
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
Table 7.2.8. Ingestion Exposure Assessment for the Composting Option
Ingestion
Benchmarks
Ranking Ratios
Chemical Species
ADD
(mg/kg d)
RI D (mg/kg d)
RSD (mg/kg d)
ADD/RfD
LADDa/RSD
Total Dioxins/furans
na
2.0E-08
7.7E-10
na
na
Total PAHs
na
nb
1.4E-05
na
na
Arsenic
na
3.0E-04
6.7E-05
na
na
Cadmium
1.2E-05
1.0E-03
nb
1.2E-02
na
Chromium
2.3E-03
3.0E-03
nb
7.7E-01
na
Copper
6.3E-03
1.0E-02
nb
6.3E-01
na
Iron
2.5E+00
7.0E-01
nb
3.6E+00
na
Lead
1.9E-04
nb
1.2E-02
na
2.3E-04
Manganese
2.7E-03
1.4E-01
nb
1.9E-02
na
Nickel
2.1E-04
1.1E-02
nb
1.9E-02
na
Zinc
2.5E-02
3.0E-01
nb
8.3E-02
na
Abbreviations: d = day; ADD = average daily dose; RiD = reference dose; RSD = risk-specific dose for target risk of 1.0E-04;
LADD = lifetime average daily dose; PAH = polycyclic aromatic hydrocarbon; nb = no benchmark available; na = not assessed.
Notes: Table includes results associated with the compost windrow and the 4.05 ha compost application area. For the windrow,
5% of the liquid released from carcasses seeps to the ground below. Compost is tilled into soil to a depth of 20 cm. No offset
distance separates the compost application area and the lake. Ingestion sources include agricultural products grown on site, fish
caught from the on-site lake, and drinking water drawn from an on-site well.3 Cancer oral slope factors represent cancer risk over
a lifetime of exposure. Therefore, average daily exposure dose for the first or maximum year of exposure (i.e., the ADD) is
divided by 70 years to calculate the LADD.
carbon bulking material that underlies the carcasses, and a portion of the leached chemicals from
the windrow are "filtered" out by soil before the leachate reaches groundwater. In addition,
because the windrow is effective at retaining metals and other chemicals present in the carcasses,
these are present in the finished compost when it is applied to surface soil.
When the finished compost is tilled into surface soil, the chemicals are available for plant uptake,
incidental ingestion by livestock, and erosion and runoff to surface water. As shown in Table
7.1.10, exposures estimated for finished compost application are below benchmark values, with
the exception of the estimated exposure for iron. The modeling approach for compost
application, however, did not include an offset distance between the 4.05 ha application area and
the lake. Thus, chemicals in eroded soils from the application area could not be filtered out by
vegetated soil between the compost application area and the lake.
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
Table 7.2.9. Ingestion Exposure Assessment for the Composting Option - Windrow Only
Ingestion
Benchmarks
Ranking Ratios
Chemical Species
ADD
(mg/kg d)
RI D (mg/kg d)
RSD (mg/kg d)
ADD/RfD
LADDa/RSD
Total
na
na
Dioxins/furans
na
2.0E-08
7.7E-10
Total PAHs
na
nb
1.4E-05
na
na
Arsenic
na
3.0E-04
6.7E-05
na
na
Cadmium
na
1.0E-03
nb
na
na
Chromium
na
3.0E-03
nb
na
na
Copper
3.1E-12
1.0E-02
nb
3.1E-10
na
Iron
7.0E-10
7.0E-01
nb
1.0E-09
na
Lead
na
nb
1.2E-02
NA
na
Manganese
1.5E-12
1.4E-01
nb
1.1E-11
na
Nickel
2.6E-13
1.1E-02
nb
2.3E-11
na
Zinc
1.1E-10
3.0E-01
nb
3.7E-10
na
Abbreviations: d = day; ADD = average daily dose; RiD = reference dose; RSD = risk-specific dose for target risk of 1.0E-04;
LADD = lifetime average daily dose; PAH = polycyclic aromatic hydrocarbon; nb = no benchmark available; na = not assessed.
Note: Chemicals released from the windrow are contained in the 5% of the liquid released from carcasses that seeps to the ground
below. Ingestion sources include drinking water drawn from an on-site well and fish caught from the on-site lake.
a Cancer oral slope factors represent cancer risk over a lifetime of exposure. Therefore, average daily exposure dose for the first
or maximum year of exposure (i.e., the ADD) is divided by 70 years to calculate the LADD.
Table 7.2.10. Ingestion Exposure Assessment for the Composting Option - Soil Amended
with Finished Compost
Ingestion
Benchmarks
Ranking Ratios
Chemical Species
ADD
(mg/kg d)
RI D (mg/kg d)
RSD (mg/kg d)
ADD/RfD
LADDa/RSD
Total Dioxins/furans
na
2.0E-08
7.7E-10
na
na
Total PAHs
na
nb
1.4E-05
na
na
Arsenic
na
3.0E-04
6.7E-05
na
na
Cadmium
1.2E-05
1.0E-03
nb
1.2E-02
na
Chromium
2.3E-03
3.0E-03
nb
7.7E-01
na
Copper
6.3E-03
1.0E-02
nb
6.3E-01
na
Iron
2.5E+00
7.0E-01
nb
3.6E+00
na
Lead
1.9E-04
nb
1.2E-02
na
2.3E-04
Manganese
2.7E-03
1.4E-01
nb
1.9E-02
na
Nickel
2.1E-04
1.1E-02
nb
1.9E-02
na
Zinc
2.5E-02
3.0E-01
nb
8.3E-02
na
Abbreviations: d = day; ADD = average daily dose; RiD = reference dose; RSD = risk-specific dose for target risk of 1.0E-04;
LADD = lifetime average daily dose; PAH = polycyclic aromatic hydrocarbon; nb = no benchmark available; na = not assessed.
Notes: Compost is tilled into 4.05 ha of soil to a depth of 20 cm. No offset distance between the compost application area and the
lake. Ingestion sources include agricultural products produced at the compost application site and fish caught from the on-site
lake.
a Cancer oral slope factors represent cancer risk over a lifetime of exposure. Therefore, average daily exposure dose for the first
or maximum year of exposure (i.e., the ADD) is divided by 70 years to calculate the LADD.
Figure 7.1 provides a visual comparison of the chemical ranking ratios by management option
and exposure route (i.e., inhalation or ingestion). For the combustion-based options, which are
177
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
the only options with estimated inhalation exposures, the figure shows that exposures normalized
to TRVs via inhalation and ingestion pathways are comparable to each other. These ranking
ratios tend to be well above ranking ratios estimated for ingestion pathways associated with
leaching from burial, the compost windrow, and the temporary carcass pile. Ranking ratios
estimated for pathways following the application of compost to surface soil are more similar in
magnitude to the ranking ratios for pathways associated with open and air-curtain burning than
for burial and the compost windrow. These patterns reflect differences between the exposure
pathways (e.g., surface versus subsurface fate and transport) associated with the management
options. In addition, differences in data sources available and methods used for different
exposure pathways are likely to contribute to the patterns of chemical ranking ratios across
options.
Infants under the age of 1 year might be bottle fed with powdered formula reconstituted with
water drawn from an on-site groundwater well. Estimated infant ingestion exposures for the
livestock carcass burial option included in Table 6.3.14 are compared with the TRVs shown in
the last column of Table 7.2.11. Ingestion of nitrates/nitrites, of particular concern for infants,
appear to be well below the RfD even using the highest 1-week concentration estimated (for the
first week following burial). Nitrate/nitrite concentrations in well water averaged over the first
two months are estimated to be one order of magnitude lower than during the first week after an
on-site burial. Estimated nitrate/ni trite concentrations averaged over the first year are two orders
of magnitude lower than for the first week after on-site burial.
For the remaining chemicals, the estimated concentrations averaged over the first year are
compared with the RfD values (last column in Table 7.2.11) as described in Appendix L. All
exposure estimates are below RfDs, which indicates that non-cancer health effects are not
expected in infants.
178
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
Ingestion: j.
Storage Pile
Inhalation:
Open Burning
Inhalation:
Air-curtain Burning
Ingestion:
Open Burning
Ingestion:
Air-curtain Burning
Ingestion: I
Burial |
Ingestion:
Compost Windrows
Ingestion:
Compost Application
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
7.2.11 Ingestion Ranking Ratios for Infants with Formula Made Using Well Water3
Ranking Ratio Toxicity
Chemical Species Open Burning Air Curtain Burialb Composting Reference Dose
Avg
95th%
Avg
95th%
Avg
95th%
Avg
95th%
(mg/kg (lay)
Total Dioxins/furans
1.4E-14
3.3E-14
2.5E-14
5.9E-14
na
na
na
na
2.0E-08
Arsenic
8.8E-07
2.0E-06
1.6E-06
3.6E-06
na
na
na
na
5.0E-03
Cadmium
1.4E-06
3.3E-06
1.0E-06
2.4E-06
na
na
na
na
5.0E-04
Chromiumb
2.6E-04
6.1E-04
4.3E-04
9.9E-04
na
na
na
na
3.0E-03
Copper
2.1E-07
4.9E-07
2.6E-07
6.0E-07
2.2E-07
5.1E-07
1.7E-08
3.8E-08
1.0E-02
Iron
9.6E-06
2.2E-05
1.1E-05
2.4E-05
8.7E-07
2.0E-06
6.4E-08
1.5E-07
7.0E-01
Lead
na
na
na
na
na
na
na
na
NoRfD
Manganese
2.6E-05
6.1E-05
4.6E-05
1.1E-04
3.6E-08
8.4E-08
2.7E-09
6.2E-09
1.4E-01
Nitrates/nitrites
na
na
na
na
6.6E-04
1.5E-03
2.3E-06
5.3E-06
1.0E+00
Zinc
5.5E-07
1.3E-06
1.9E-06
4.3E-06
1.7E-07
4.0E-07
1.3E-08
3.0E-08
3.0E-01
Abbreviations: Avg = average; 95th = 95th percentile; d = day; nd = no data; na = not assessed.
a Avg (average) columns calculated using the mean water ingestion rate of 0.137 L/kg-day for an infant less than 1 month old (highest mean ingestion rate for infants less than 1
year of age, see Table 6.2.1. 95th% = ingested daily dose assuming 95th percentile water ingestion rate for infant 1 to 3 months old (highest 95th percentile ingestion rate reported
for infants less than 1 year).
b The chromium reference dose (RiD) of 3.0E-03 is for a chronic USEPA RiD documented in IRIS for chromium IV. The most likely form of chromium to reach groundwater has
not been evaluated.
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
The following factors were used to compare the management options on the basis of the
chemical ranking ratios:
¦ Two highest ranking ratios - The highest ranking ratios (i.e., highest estimated exposures
relative to toxicity benchmarks) indicate the exposure pathways and chemicals that might be
"risk drivers" for a management option. When using a maximum value of a distribution,
particularly when there is significant uncertainty in the data and methods used to calculate
values in the distribution, there is a potential for biasing conclusions based on an
unreasonable outlier for a parameter in the calculations. To reduce that possibility when
comparing management options, the two highest ranking ratios for each management option
are compared across management options.
¦ Median ranking ratio - The median ranking ratio represents a central-tendency of the
distribution of the chemical ranking ratios for a management option. The median allows
comparisons of the magnitude of the ranking ratios calculated for the options that is less
likely to be influenced by outliers. First, for each chemical assessed for a management
option, as stated above, ranking ratios are determined for each exposure route (i.e.,
inhalation or ingestion) and each health endpoint (i.e., cancer or non-cancer). In theory, a
single chemical might have three ranking ratios associated with it: inhalation non-cancer,
ingestion non-cancer, and ingestion cancer. The maximum of those three ratios (or possibly
the only ratio assessed for a given chemical) is assumed to be the "risk driver" for that
chemical. Thus, each chemical has a single ranking ratio associated with it. After the single
maximum ranking ratio was selected for each chemical, the median ranking ratio across all
chemicals was calculated for each carcass management option.
The values of the two highest ranking ratios and the median value across all chemicals for each
management option are listed in Table 7.2.12. The table provides a brief summary of the
exposure potential for each option. Exposures associated with carcass transportation and
handling are listed separately so that differences among the management options are not
obscured by exposures that are assumed to be the same for all management options.
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters
Table 7.2.12. Chemical Ranking Ratio Summary
Carcass
Ranking Evaluation
Management
Scenario
Top Two Ranking Ratios
Median Ranking Ratio
Summary of Exposure Potential
Temporary Carcass
Storage Pile
¦ 5.4E-09 iron ingestion;
¦ 8.1E-10 zinc ingestion
Median of 5 chemical ratios:
3.9E-10
Exposures from carcass transportation and handling
were assumed to be negligible except those arising from
storage pile leaching. The estimated exposures are well
below those estimated for the carcass management
options.
Open Burning
¦ 5.8E-01 manganese inhalation;
¦ 1.8E-01 nickel inhalation
Median of 11 chemical ratios:
4.0E-02
The combustion-based carcass management options have
equivalent exposure pathways, and these include more
chemical releases to the enviromnent than other options.
They are the only options with potentially significant
Air-curtain Burning
¦ 1.4E+01 manganese inhalation;
¦ 9.3E-02 chromium inhalation
Median of 11 chemical ratios:
2.0E-02
inhalation exposures. While air-curtain burning lias
higher top ratios than open burning, the median ranking
ratio is higher for open burning.
Burial
¦ 2.0E-08 iron ingestion;
¦ 7.4E-09 zinc ingestion
Median of 5 chemical ratios: 6.3E-
09
For the assumed site setting and carcass burial scenario
evaluated, burial has the potential to result in chemical
exposures through groundwater and fish ingestion. The
estimated ingestion exposures normalized to toxicity are
lower than the three other on-site carcass management
options and are similar to the ranking ratios for the
windrow component of the composting option and the
temporary carcass storage pile.
Composting
Windrow
¦ 1.0E-09 iron ingestion;
¦ 3.7E-10 zinc ingestion
Compost Application
¦ 3.6E+00 iron ingestion;
¦ 7.7E-01 chromium ingestion
Windrow
Median of 5 chemical ratios:
3.1E-10
ConiDOSt Amplication
Median of 8 chemical ratios:
5.1E-02
The scenario considered both leaching from the windrow
and application of finished compost without erosion
controls or an offset distance between the application
site and the lake. The highest exposures for this option
are for children's ingestion of fish caught in the lake
near the compost application field. Exposures from
compost-amended soils can be made negligible by using
of erosion controls at the compost application site or by
adhering to a setback distance between application and
the lake.
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Based on the information presented in Table 7.2.12, Tier 2 rankings for chemical exposures
only are presented below, with rank or number 1 indicating the on-site management option
with the least potential for adverse health effects from chemical exposures.
1. Compost Application. The highest median ranking ratio and highest two chemical-specific
ranking ratios were estimated for the application of finished compost. As shown in Figure 7.1
and Table 7.2.12, the ranking ratios for compost application are, collectively, similar to and
only slightly above the ranking ratios for the combustion-based options. Composting does
not destroy metals and other persistent chemicals in the carcasses. Thus, almost all of the
chemical mass for persistent chemicals remains in the finished compost. That contrasts with
the combustion options, where the fate of persistent chemicals is split between air emissions
and land-disposed ash. In addition, with compost applied to a 4.05 ha (10 ac) area, the
chemicals contained in the compost are added to soil in higher concentrations (e.g., in units
of mg/m3) in that area than chemicals deposited from air to surface soils over much larger
areas from the combustion-based options. Runoff and erosion from the area to which
compost is applied can move more chemical from that area to surface water than runoff and
erosion from the entire watershed receiving deposition from air for the combustion options.
Although compost application is ranked highest among the on-site management options, it is
very likely that exposures are overestimated by a limitation of the modeling approach. In
particular, the model used to estimate erosion from the compost application site provides no
means to specify an offset distance between the 4.05 ha compost application area and the on-
site lake. In actual practice, compost rarely would be applied immediately adjacent to a lake,
especially without the use of erosion control. When a distance separates the compost
application field and the water body, the intervening land area acts as a buffer that retains soil
and compost particles eroded from the compost application area. Potential exposures through
these pathways can be controlled with mitigation measures described in Table 7.4.1.
2. Combustion-based Options. The two on-site combustion-based management options
included in the exposure assessment had the highest estimated exposure levels. These options
include direct inhalation exposure to chemicals produced by combustion over 48 hours.
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Between the two combustion-based options, open burning has a higher median ranking ratio
than air-curtain burning, although air-curtain burning appears to have a higher maximum
ranking ratio than open burning. If the coal added to the open pyre is bituminous or
subbituminous, the ranking ratio for PAHs for open burning would be higher than in Figure
7.1 by as much as a factor of 14 (see Appendix A); however, that small difference would not
affect the overall pattern of ranking ratios. Thus, the distributions of ranking ratios for the
two combustion-based options are similar, that is, not distinguishable from each other given
the uncertainties in estimating exposures. For this reason, the combustion-based options are
ranked together.
Emissions from air-curtain burning are sensitive to the assumed quantity of wood burned.
This assessment assumes a fuel-to-carcass ratio of 4:1 on a weight basis. This assumption
was obtained from the expert workshop discussed in Section 2.5. However, information
available from the literature (see Section 3.3) indicates that air-curtain burning might require
fuel-to-carcass ratios from 1:1 to greater than 4:1. Emissions rates (not shown) calculated
with a 2:1 fuel ratio resulted in lower estimated concentrations of PAHs compared with open
burning and lower concentrations of dioxins/furans than predicted for air-curtain burning
based on the 4:1 ratio.
3. Burial. On-site burial is one of three carcass management activities with potential "below
ground" exposure pathways through groundwater, the other two being temporary carcass
storage and the windrow phase of composting. As shown in Figure 7.1 and Table 7.2.12,
ranking ratios estimated for those three activities tend to be several orders of magnitude
below the ranking ratios for the management options with above ground exposure pathways.
In addition, the ranking ratios are at least 8 orders of magnitude below 1.0, which indicates a
very low likelihood of adverse health effects, particularly with the conservative assumptions
of this assessment (e.g., no dilution or attention of chemicals in groundwater, drinking water
obtained from a shallow, unconfined aquifer). Ranking ratios are greater for burial than for
temporary carcass storage and the compost windrow because burial releases more leachate to
soils than the other activities.
One reason that exposures via groundwater are lower than exposures via above-ground
pathways is that chemicals in the liquids released from the carcasses can be filtered out by
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the soil before they reach groundwater. Partitioning to soil is estimated with chemical-
specific soil-water partition coefficients. The effect of partitioning on chemical fate is
consistent with field experiments by Glanville et al. (2006), who found chloride ion (Cl~)
concentrations above background in soil below a compost windrow to a depth of 120 cm, but
other leachate components declined more quickly with depth than CI". Chloride ions do not
sorb to soils particles (which also have a net negative charge), and so are good markers of
maximum leaching distance. Concentrations of total nitrogen, ammonia, and nitrates
decreased with increasing depth and were significantly different from background only in the
top 15 cm of soil when corn stalks were used as the bulking agent. As discussed in Section
7.3, differences between the ranking ratios estimated for the different pathways is attributable
in part to unavoidable differences in the uncertainty and conservatism of the source data and
modeling approaches.
4. Temporary Carcass Storage. The temporary carcass storage pile is assumed to be on bare
ground with no containment of liquids released by the carcasses during two days of storage.
The median and maximum two ranking ratios for the storage pile are very low for the reasons
discussed above for the burial option, as well as the very short duration of releases (two days)
compared with burial.
5. Compost Windrow. Among the carcass management activities evaluated, the lowest
potential exposures were estimated for the windrow phase of the composting option.
Chemical exposures from the composting windrow are several orders of magnitude lower
than those from compost application. Properly constructed and maintained windrows are
effective at containing chemicals from carcass decomposition while allowing the water in
leachate to evaporate from the bulking materials. Although, composting is effective at
breaking down organic matter, metals and other persistent chemicals are not destroyed and
remain in the windrow and finished compost.
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7,2,3, Tier 2 Ranking for Microbial Exposures
For microbes, the Tier 2 ranking of the four on-site carcass management options uses the
microbial exposure estimates presented in Section 5. As discussed previously, microbial
exposures are not estimated for all of the exposure pathways in the conceptual models; the
pathways that were quantified are shown in bold type in Table 6.1.2. For convenience, Table
6.1.2 is repeated here in Table 7.2.13. The exposure pathways that were not quantified for one or
more reasons are included in Table 7.2.13 in plain (not bold) type. The reasons that certain
pathways were not assessed were discussed in Section 6.1.
Like chemical exposures, microbial exposures associated with carcass transportation and
handling steps that precede each of the on-site management options are evaluated in Tier 2
separately from the management options themselves (Table 7.2.13).. The carcass transportation
and handling steps, and their resulting microbial exposures, are assumed to be the same for all
carcass management options.
Unlike chemicals, TRVs are not available for microbes. To allow a relative risk-based evaluation
of the exposures for microbes, exposures are compared to available ID50 values reported in the
literature for the three microbes selected for this assessment. The three microbes should represent
three subsets of the potential microbial hazards identified in Table 2.4.4 (Section 2) - prions,
spore-forming bacteria, and non-spore forming bacteria. The ID50 values for B. anthracis, E. coli
0157:H7, and scrapie-inducing prions (PrPSc) are provided in Table 6.1.1 (and included in Table
7.2.14). A human ID50 value is not available for prions, so the reported ID50 value for cattle is
used instead.
As stated above, for microbes, only human exposures associated with groundwater ingestion are
quantified. The exposure estimates are compared to the reported ID50 values. Exposure estimates
at or above the ID50 indicate that possibly half of the farm residents, especially sensitive
populations, might fall ill following the ingestion of groundwater. Values many orders of
magnitude below the reported ID50 value are unlikely to result in illness in a small population of
farm residents.
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Table 7.2.13. Potential Human Exposure Pathways and Routes for Livestock Carcass Transportation and Handling Activities
and Management Options - Microbes
Carcass Transportation and Handling
Carcass Management Options
Exposure
Source
Carcass
Handling
Temporary
Carcass Storage
Carcass
Transportation
Open Burning
Air curtain
Burning
Burial
Composting
Inhalation
1) Airb
1) Airb
2) Leachate —>
Soil —> GW —>
Aerosolb
1) Airb
1) Airb
2) Ash —> GW —>
In-home Aerosolb
1) Airb
2) Ash —> GW —>
In-home Aerosolb
1) Airb
2) Leachate —>
GW —> In-home
Aerosolb
1) Airb
2) Compost —>
GW —*~ In-home
Aerosolb
Incidental
Ingestion
2) Hand-to-
mouth ingestion
b,c
—
2) Accident —>
soilb,c
3) Air —> Soilb
3) Air —> Soilb
—
—
Dermal
Contact
3) Dermal
contact0
—
3) Accident —>
soil0
—
—
—
—
Fish Ingestion
—
3) Leachate —>
Soil —> GW —>
SW Fishb
—
4) Air —> SW —>
Fishb
5) Air —> soil —>
SW -> Fishb
6) Ash —> GW —>
SW Fishb
4) Air —> SW —>
Fishb
5) Air —> Soil —>
SW Fishb
6) Ash —> GW —>
SW Fishb
3) Leachate —>
GW —> SW —>
Fishb
3) Compost —>
Soil —> SW —>
Fishb
4) Compost —>
GW —> SW —>
Fishb
Groundwater
Ingestion
—
4) Leachate —>
Soil -> GWa
—
7) Ash -> GWa
7) Ash -> GWb
4) Leachate —>
GWa
5) Compost —>
Leachate —>
GWa
Ingestion of
Food
Produced on
the Farm
—
5) Air —>
Plants/livestock13
6) Leachate —>
GW —>
Livestock13
—
8) Air —> Plants/
Livestock13
9) Air —> Soil —>
Plants/
Livestock13
10) Ash->GW
—> Livestock13
8) Air —> Plants/
livestock13
9) Air —> Soil —>
Plants/
Livestock13
10) Ash->GW
—> Livestock13
5) Air —> Plants/
Livestock13
6) Leachate —>
GW —>
Livestock13
6) Air —> Plants/
Livestock13
7) Compost —>
Soil —> GW —>
Livestock13
Abbreviations: "—" = no exposure pathways; SW = surface water; GW = groundwater.
Note: Exposure pathways shown in bold were included in the quantitative exposure assessment.
a Quantitative methods were available for exposure assessment; results are presented in Section 5.
b Potential exposures were assumed to be negligible based on source conditions or microbial properties.
c Environmental releases or exposures were assumed to be adequately controlled by existing pollution control regulations or the use of personal protection equipment (PPE).
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For humans, all exposure estimates for ingestion were below the reported ID50 values for all
microbes at all time intervals (from initial exposure to 1 year). The lowest and highest microbial
exposure estimates for groundwater ingestion, the ID50 values associated with these microbes,
and the transportation and handling activities and management options associated with the
exposure estimates, are summarized in Table 7.2.14.
Table 7.2.14. Ingestion Exposure Assessment for Microbes
Management
Option
Highest Exposure
Lowest Exposure
Microbe
ID 50
Estimate/
Estimate/ Reference
Time Interval
Time Interval
Bacillus
anthracis
Temporary
carcass storage
Burial
Composting
1,000s-
10,000s
spores
4.08E+00 particles/
initial
1.52E+00
particles/
1 year
WHO
(2008)
Escherichia
coli 0157:H7
Temporary
carcass storage
Burial
10-100
organisms
1.35E-05 particles/
initial
2.64E-17 particles/
1 year
Gurian et al.
(2012)
Prions (PrPSc)
Temporary
carcass storage
Open pyre
Burial
Composting
Unknown for
humans;
value for
cattle 5.5E-
03 particles
4.08E-04 particles/
initial
5.25E-30 particles/
1 year
Yamamoto
et al. (2006)
Abbreviations: ID50 = infectious dose at which 50% of the exposed population falls ill; PrPSc causes the disease scrapies.
As illustrated in Table 7.2.14, the exposure estimates for E. coli 0157:H7 are significantly lower
than the associated ID50 value for humans (>7 orders of magnitude). It is unlikely that exposure
to those concentrations of E. coli 0157:H7 in drinking water would result in illness in local
healthy human populations. E. coli 0157:H7 is representative of a larger group of non-spore
forming bacteria that are expected to be released from livestock carcasses present in the storage
pile and the burial pit (see Table 2.4.4). Compared with the ID50 value for this non-spore forming
species of bacteria, the estimated exposure indicates that human illness is very unlikely.
The exposure estimates for B. anthracis are also below the reported ID50 value for humans.
Exposure estimates after the initial release and over the first year of exposure to groundwater is
3-4 orders of magnitude less than the ID50. Like coli 0157:H7, it is unlikely that exposure to
those concentrations of B. anthracis would result in illness in a small, localized, population of
humans. B. anthracis represents a larger group of spore-forming agents that are expected to be
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released from livestock carcasses in the storage pile, the compost pile, and the burial pit (see
Table 2.4.4). Compared with the ID50 value for B. anthracis, the estimated exposure indicates
that human illness is possible, but unlikely in a relatively small population of farm residents. It
should be noted that the sensitive populations are more vulnerable than others (Gerba et al 1996).
The exposure estimate for scrapie-inducing prions at the initial exposure is closer to its ID50
value than E. coli 0157:H7 or B. anthracis; however, an ID50 value is available only for cattle,
not humans. The exposure estimate after the initial release to groundwater (time 0) is only one
order of magnitude less than the ID50 value for cattle. However, the estimated exposure one year
later is 27 orders of magnitude less than the ID50 value for cattle. Prions were not selected to
represent other microbial hazards identified in Table 2.4.4; they were selected because they are
the most resistant to inactivation by environmental stressors of the microbial categories. In
contrast to the first two microbes, releases of infectious prions are possible for three of the on-
site carcass management options (i.e., composting, burial, and open-burning), as well as for the
carcass storage pile. The estimates of exposure at most time intervals are not likely to result in
illness in local healthy human populations, but illness might occur if groundwater is ingested
following the initial release of prions to this medium and if the human ID50 value is close to the
ID50 value for cattle. Each management option includes exposure to microbes via carcass
handling, transportation, and the temporary carcass storage pile; however, those exposures are
associated with all carcass management options equally.
Given the assumptions and methods of this assessment, the ratio of exposure estimate to ID50
values for each of the three microbes evaluated did not distinguish among the four on-site
livestock carcass management options. Thus, to rank those options relative to each other, one key
criterion was used: efficacy of each management option in thermally inactivating the pathogens
examined. Based on that criterion, the four on-site management options are ranked from the
potentially lowest microbial exposure (1) to the highest (4) below.
1. Air-curtain Burning. Air-curtain burning at temperatures approximating 850°C is likely to
destroy or inactivate essentially all three types of pathogens, including spore-forming
bacteria and prions. Thus, no exposure pathways are likely for microbes associated with air-
curtain burning.
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2. On-site Open Burning. The temperatures reached in an open pyre (e.g., approximately
550°C) should inactivate bacterial cells and spores; the exception is that prions could survive.
Subsequent burial of the remaining ash eliminates above ground exposure pathways for
surviving prions. Uneven burning across an open pyre could allow survival of other
thermotolerant spore-forming bacteria and other microbes.
3. On-site Composting, Windrow. The heat produced by thermophilic bacterial decomposition
of composted livestock carcasses can raise the temperature of materials in the compost pile to
55°C for several days. Even that modest temperature is sufficient to inactivate virus particles
and bacterial cells, although not spores from the spore-forming species of bacteria. Particles
in leachate released from the compost pile should be contained in the bulking material below
the windrow, with perhaps 5% leaking to subsurface soils during precipitation events. Prions
and spore-forming bacteria identified in Table 2.4.4, like B. anthracis, Clostridium
perfringens, and Coxiella burnetii, could survive the composting process and be present in
finished compost in which the bulking materials surrounding the carcasses are mixed in with
the carcass remains. Viable prions and bacterial spores could, therefore, be applied in
finished compost to soils on the farm. If a windrow is allowed to sit for several additional
weeks, the additional heating could provide for more complete inactivation of spore-forming
bacteria (Schwarz and Bonhotal 2014). In the field, most human exposures to B. anthracis
are via spores on the skin or fur of mammals (wool, hides, or hair) and not via consumption
of crops that might have come in contact with infectious spores (CDC 2015). Persons
handling infected mammals might contract inhalation anthrax (e.g., spores aerosolized during
industrial processing of contaminated materials) or cutaneous anthrax (e.g., if spores contact
an open cut or scrape on the persons' skin). Ingestion anthrax could occur if raw or
undercooked meat from infected animals is consumed; however, that generally occurs where
livestock are not vaccinated against anthrax and where food animals are not inspected before
slaughter (CDC 2015).
4. Burial. Although the fewest exposure pathways were identified in the conceptual model for
burial, this option is associated with the greatest potential for pathogen survival over the long
term. In addition, no thermal inactivation of microbes is expected. The conditions of the
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burial pit impact pathogen viability in different ways, adding a high level of variability to
pathogen survival. For some pathogens, the anaerobic conditions of the burial pit favor a shift
to survival forms (e.g., spores). The spores can remain viable for long periods of time and are
environmentally resistant. Analyses of livestock carcass burial sites have reported the
detection of a wide range of microbes in and soil samples surrounding these burial sites
(Davies and Wray 1996; Joung et al. 2013). However, for other pathogens, the conditions of
a burial trench might prevent sporulation or regrowth. Some microbes in leachate from
buried carcasses might escape adsorption to soil particles when traveling from the burial
trench toward groundwater. If microbes do not reach groundwater, then risks from this key
exposure pathway for both humans and livestock becomes negligible. If microbes reach
groundwater, recharge of groundwater into the on-site lake similarly would result in very low
concentrations in the water column. Even small lakes would dilute concentrations of
pathogens reaching the lake via groundwater recharge to negligible concentrations.
In conclusion, for microbes the four on-site carcass management options can be ranked by their
ability to thermally inactivate microbes as shown in Table 7.2.15, with rank 1 indicating the
option with the lowest exposure potential. Table 7.2.13 identified the exposure pathways
evaluated for microbes with bold text. The temporary carcass storage pile would be used prior to
the management of carcasses for each option, and exposures originating from the pile should
affect each management option equally. Similarly, on-site carcass handling is the same across
management options. Therefore, temporary carcass storage and handling do not affect the
ranking of management options.
Table 7.2.15. Ranking the Four On-site Carcass Management Options by Relative Risk
from Microbes
Carcass Management Option
Rationale
1
Air-curtain burning
All microbes inactivated or destroyed, lowest relative risk
2
Open-pyre burning
Prions survive, other microbes inactivated or destroyed
3
Composting: windrow & application
Prions and spores survive, E. coli can be inactivated
4
Burial
No thermal destruction; leachate not impeded
The temperatures and burn durations associated with combustion-based management options are
expected to destroy most pathogens. Air-curtain burning subjects particles to multiple burn
cycles and high temperatures in the burning carcasses. No microbe exposure is anticipated. On-
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site open burning might not inactivate prions, but otherwise can inactivate most types and
species of microbes.
Of the two land-based on-site options, composting and burial involve the same pathways, but the
interactions with the normal microflora would lead to different overall microbial populations and
effects. Pathogens could be present in leachate produced at the burial site and during the
composting process. The aerobic environment maintained during the composting process is
likely to favor the ability of native thermophilic microflora to outcompete pathogen populations.
The final compost product is likely to have very low populations of prions and spore-forming
bacteria remaining as contaminants, and allowing the windrow to sit for more time before
application decreases the likelihood that viable spore-forming bacteria would be present in
finished compost. Leachate from a poorly sited composting process could introduce spore-
forming bacteria and prions to groundwater sources. The anaerobic environment that
accompanies many burial sites is likely to favor pathogens shifting to survival forms that
subsequently die, are inactivated, or become diluted below an infective dose over time. Release
to groundwater via contaminated leachate is the only pathway assessed quantitatively for burial.
Microbial releases were also identified for carcass transportation and handling activities;
however, the use of PPE and other transportation-related common practices (such as the use of
tarps) should prevent exposure to microbes from carcass handling and transportation. Four
exposure pathways were identified for temporary carcass storage. Like on-site unlined burial,
leachate produced from temporary carcass storage piles can release a broad range of pathogens,
including prions, viruses, and bacteria. Those might reach groundwater sources used for drinking
water; however, the short duration of storage should help mitigate that possibility. Of the
transportation and handling activities, the temporary carcass storage pile is associated with the
highest potential exposure to pathogens (see Section 6.1). Exposures to microbes are mitigated
through the use of PPE and other measures (e.g., tarp, lined trucks) for other carcass
transportation and handling activities.
7.3, Conclusions and Discussion of Uncertainty
Throughout the analysis, chemicals and microbes were assessed independently, because of
fundamental differences in the two types of potentially hazardous agents and differences in the
availability of suitable data and approaches (e.g., models, methods). The final rankings of the
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seven livestock carcass management options differ for chemicals and pathogenic microbes, as
described in Section 7.3.1.
Section 7.3.2 discusses key uncertainties in the exposure assessments for both chemicals and
pathogenic microbes. It also describes activities or modifications of the carcass management
processes and options that can mitigate exposures along certain pathways.
1,2,1, Conclusions
The qualitative Tier 1 assessment distinguished the three off-site management options as
releasing fewer chemicals and fewer microbes (or at lower concentrations) than the on-site
options because of regulatory emission controls (Section 7.1, Table 7.1.1). For the on-site
management options, the Tier 2 assessment quantified relative risks from chemical releases
(Sections 4 and 5), but not microbial releases (Section 6).
For chemicals, the Tier 1 and Tier 2 assessments are summarized in Table 7.3.1. The Tier 1
summary shows that (1) the off-site options are considered to pose lower risk than the on-site
options as discussed above, and (2) the off-site options are not ranked relative to each other. The
Tier 2 summary shows numerical rankings for the on-site options, with the rank of 1 posing the
lowest relative risk. Some options (e.g., air-curtain burning and open burning) were not
distinguishable from others given data gaps and uncertainty in modeling. Those options have,
therefore, the same relative rank.
The Tier 2 rankings for chemicals are based on the quantitative assessment in which different
methods were applied to model combustion releases to air and to assess fate and transport in
surface and subsurface soils, groundwater, and an on-site lake. Initial emissions of chemicals to
air and in leachate were based on measured data reported in the literature under conditions
similar to the assumptions for the hypothetical farm. Conservative assumptions filled other data
gaps, including environmental characteristics with high variation nationwide.
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Table 7.3.1. Ranking of Livestock Carcass Management Options for Chemicals
Tier 1 Description
Management Option
Principal Rationale
The qualitative Tier 1 assessment
distinguishes the off-site options from
the on-site options based on level of
regulatory control. The off-site options
are considered to pose lower risk than
the on-site options, which have
uncontrolled enviromnental releases.
The off-site options are not ranked
relative to each other.
Off-site Rendering
Carcasses processed into useful
products; wastes released under permits;
availability decreasing
Off-site Landfill
Carcass leachate contained and methane
captured; landfills at capacity are closed
and new ones built
Off-site Incinerator
Destruction of materials; air emissions
are regulated; ash is landfilled
Tier 2 Description
Rank3
Management
Option
Principal Rationale
The quantitative Tier 2 assessment
ranks the on-site options relative to
each other by comparing ratio of
estimated exposures (from data on
source emissions and fate and
transport modeling) with toxicity
reference values (TRVs).
1
Compost
Windrow
Bulking material retains most chemicals
1
Burial
Soils filter out chemicals traveling
toward groundwater
2
Air-curtain
burning
Similar release profiles; emissions
sensitive to type and quantity of fuels
used and burn temperature
2
Open Pyre
burning
3
Compost
Application
If no offset from lake; mitigate with
offset and erosion controls
a Rank 1 poses the lowest relative risk and higher numbers indicate higher relative risk.
The Tier 1 and Tier 2 assessments for microbes are summarized in Tables 7.3.2 and 7.3.3,
respectively. In Tier 1, the off-site options were ranked (i.e., highest, middle, lowest)
qualitatively based on the level of thermal destruction. Off-site options were not ranked relative
to on-site options, because different assessment methods were used in the two tiers. It should not
be assumed that the off-site options pose lower risk than the on-site options. In fact, some on-site
options offer comparable or greater thermal destruction than off-site options.
In the Tier 2 assessment, three pathogenic microbes were evaluated to represent prions, bacterial
spores, and bacterial cells (Section 6). For these microbes, all estimated exposure doses were
below the available ID50 values. A significant unknown for this assessment, however, is the
initial concentration likely in healthy livestock killed by a natural disaster. Therefore, the
rankings in Table 7.3.3 are based on thermal destruction and containment provided by the
options. These rankings assume prions could survive more management options than spores, and
bacteria that do not form spores were most susceptible to thermal inactivation. The rankings
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could be different if management options are not implemented according to guidelines.
Uncertainties associated with the microbial assessment are discussed in Section 7.3.2.
Table 7.3.2. Tier 1 Ranking of Off-site Livestock Carcass Management Options for
Microbes
Tier 1 Description
Rank3
Management
Option
Principal Rationale
The qualitative Tier 1 assessment
distinguishes the off-site options
from the on-site options based on
level of regulatory control. Among
the off-site options, rankings are
based qualitatively on the level of
thermal destruction. Off-site options
are not ranked relative to on-site
options, although some will offer
thermal destruction comparable to or
greater than on-site options.
H
Off-site Incinerator
Thermal destruction of all microbes, ash
is landfilled
M
Off-site Rendering
Thermal inactivation of all microbes
except prions, workers protected from
prion exposure with the use of PPE
L
Off-site Landfill
Contaimnent, including liner, leachate
collection, cover material, but no thermal
destruction; when capacity is reached,
landfill is closed and new ones built
Abbreviations: H = Highest rank; M = Middle rank; L = Lowest rank.
a Relative and absolute risks from microbial pathogens depends on initial concentrations in healthy cattle, which are unknown.
Table 7.3.3. Tier 2 Ranking of On-site Livestock Carcass Management Options for
Microbes
Tier 2 Description
Rankab
Management
Option
Principal Rationale
Rankings in the Tier 2 assessment are
1
Air-curtain
Thermal destruction of all microbes
based on quantitative exposure dose
estimates for a limited number of
2
Open Pyre
Thermal destruction of all microbes
except prions
exposure pathways. For those
pathways and the microbes assessed,
all estimated exposure doses were
below the available IDso values for
each representative microbe (<6, 3-4.
and ~ 1 order of magnitude lower
3
Compost:
-Windrow
-Soil application
Thermal inactivation of most microbes
during windrow decomposition phase,
incomplete inactivation of spore-forming
microbes and prions with some
decay/inactivation expected before the
application of finished compost
than the ID50 for E. coli, B.
cmthracis, and prions, respectively).
Therefore, the rankings reflect the
extent of thermal destruction.
4
Burial
No thermal inactivation of any microbes,
some decay expected
a Rank 1 poses the lowest relative risk and higher numbers indicate higher relative risk.
b Relative and absolute risks from microbial pathogens depends on initial concentrations in healthy cattle, which is unknown;
qualitative ranking is based on thermal destruction and containment.
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1.2.2. Uncertainties
The scenarios, modeling tools, and exposure estimation methods used in this assessment include
numerous assumptions that might or might not be consistent with site-specific livestock carcass
management applications. In addition, because limited data are available on the sources of
chemicals and microbes released from carcass management activities, some aspects of the
assessment use substitute data or simplifying assumptions that may over- or under-estimate the
exposures. Important sources of uncertainty affecting the exposure assessment are discussed
below. Where possible the effects of the uncertainties and limitations on over-or under-
estimation are described.
¦ Site Setting and Environment - Aspects of the hypothetical site setting that contribute to
uncertainty include the following:
• Site layout, including the distances between carcass management units and exposure
locations (e.g., the drinking water well), depth to groundwater, and lake size. Site layout
assumptions can be considered reasonably conservative (i.e., leading to higher
exposures). For example, the depth to groundwater and the distance to the drinking water
well are based on the most conservative minimal values identified from state regulations.
At most actual sites, adherence to state and federal guidelines could easily result in lower
potential exposures than represented by the conservative assumptions used for the
assessment.
Although the site layout was designed to include all exposure pathways in the conceptual
models, actual sites will not necessarily include all of the pathways. In this regard, the
site setting is likely to overestimate actual exposures. For example, the assessment
assumes that sources of groundwater contamination affect a nearby drinking water well.
This scenario implies that drinking water is obtained from a shallow unconfined aquifer.
However, as shallow wells are more susceptible to contamination than deeper wells, most
actual sites would be expected to obtain drinking water from deeper wells less susceptible
to contamination.
• Environmental characteristics - Related to the site setting are assumptions about the
characteristics of soil, surface water, and sediment used by the fate and transport models.
In most cases, these assumptions are default values recommended in the USEPA (2005a)
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documentation, which in turn are based on a number of elements, such as the best science
available and professional judgement. As a national-level guidance, the HHRAP
recommendations typically reflect national average conditions (USEPA 2005a).
Environmental characteristics at particular sites could contribute to exposures that are
either greater to or less than those estimated with the assumptions used for this
assessment.
• Meteorological conditions — Meteorology data were selected for a location in Iowa,
because of the predominance and diversity of agricultural activities in the central
Midwest, and because this region is not characterized by extreme weather conditions
(e.g., aridity). These data affect air dispersion modeling and leaching from combustion
ash for the combustion-based management options. The analysis uses estimated air
concentrations of chemicals for the 48 hr period during the year when the weather would
produce the greatest deposition to ground. Leaching from buried ash is a function of the
total annual rainfall and the number of times it rains per year. Excluding factors other
than weather, the exposure estimates could be greater or lower than would be expected at
other sites (e.g., wetter or drier).
¦ Carcass Management Options - The assessment requires assumptions about the design and
implementation of each of the carcass management options. Examples of these assumptions
include
• The sizes and dimensions or carcass management units
• Method and duration of carcass storage before disposal
• Types and amounts of combustion fuels
• Combustion temperatures and durations
• The use of tarps, erosion controls, PPE, and other mitigation
• The use of finished compost
These assumptions were based on typical practices described in the available literature or
identified by experts (see Section 2.5). Although the assumptions about the carcass
management options were chosen to represent typical practices, variations in actual practice
are likely to result in exposures that may be higher or lower than estimated.
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* Fate and Transport Modeling - The assessment uses various models to estimate
concentrations of chemicals in air, soil, water, and foods. The models include existing
computer models, e.g., AERMOD, MIRC, AQUAWEB), as well as modeling tools
developed for this project based on HHRAP (USEPA 2005a) and ad hoc methods (e.g., for
estimating leaching from combustion ash). Sources of uncertainty associated with fate and
transport modeling for this assessment include the following:
• Input data - Each model requires input such as initial chemical concentrations, emission
factors, and chemical properties (e.g., vapor pressure, partition coefficients, biotransfer
factors), as well as inputs discussed separately above (e.g., scenario assumptions,
environmental characteristics). These data are subject to various limitations and
uncertainties, discussed in Sections 3 and 4, which individually and collectively may
cause exposures to be under- or over-estimated.
• Model precision and accuracy - The models and modeling approaches used in the
assessment have varying levels of sophistication. For example, AERMOD provides a
more refined approach to estimating air dispersion and deposition of chemicals than the
approach for estimating chemical movement to groundwater and subsequent well
interception. On the other hand, natural variation in hydrological features underlying
livestock rearing locations across the United States is substantial and no one setting is
likely to be representative. In general, the less refined approaches are likely to over-
estimate exposures that more refined models, because conservative assumptions are used
to address data gaps and conservative approaches address uncertainties in model form.
For example, the groundwater modeling approach assumes there is no dispersion or
attenuation of the chemicals in groundwater as it flows along an unconfined aquifer for
30.5 m (100 ft) to the downgradient drinking water well.
The uncertainties associated with fate and transport modeling data and methods can
individually contribute to under-or over-estimation of exposures. In general, however, the
assessment uses more conservative assumptions and approaches, which would most likely
result in over-estimates of possible exposures.
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Because multiple models are used and because modeling requirements differ by management
option, the level of uncertainty attributable to fate and transport modeling varies among
management options and among exposure pathways.
¦ Potential Microbial Hazards - The assessment requires assumptions about the pathogenic
microbes that could be present in livestock categorized as "healthy." Livestock are assumed
to be free from the signs or symptoms associated with infection with a given pathogen. The
list of potential microbial hazards was developed by considering the specific types of
microbes (e.g., viruses, bacteria, fungi) commonly present in livestock such as cattle, poultry,
and swine. FADs were not considered; however, pathogens less frequently isolated from U.S.
livestock with long incubation periods were included. Examples of these microbes include B.
anthracis and prions that produce scrapie disease. Several of the potential microbial hazards,
categorized as prions and spores of spore-forming bacteria that are identified in this
assessment are resistant to high temperatures would not be inactivated by combustion-based
management options or other thermal-based processes, such as composting. The ability of
these microbes (i.e., prions and bacterial spores) to remain active despite the temperatures
reached in open burning and in composting contributes to the less favorable ranking of those
two management options. However, if the assumption that prions and spore-forming bacteria
are present in livestock is incorrect, and these microbes are not present in managed livestock,
then the on-site open burning and composting options would be ranked similarly to air-
curtain burning for bacterial cells that cannot produce spores. The thermal processes
associated with air-curtain burning, on-site open burning, and composting would inactivate
all potential microbial hazards if prions and spore-forming bacteria were not present in
managed livestock. Unlined burial would remain the least favorable management option,
because the carcasses remain at ambient temperatures (i.e., no thermal inactivation), and
there are no regulations that require containing or collecting leachate or gases.
¦ Exposure Estimation - Exposures are estimated using mean exposure factor values (e.g.,
body weight, daily food ingestion rates) for adults and children. Mean values are used to
represent the general population and could under- or over-estimate exposure for some people,
such as people who are extremely active or people who are sedentary, respectively.
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The conceptual models and exposure estimation approach assume that farm residents
consume a diet of home-grown foods including fruits, vegetables, meat and dairy products, as
well as fish caught from the on-site lake. This scenario is not typical, and will overestimate
food ingestion exposures, even using mean ingestion rates as described above.
The combined impact of these uncertainties has not been quantified, nor has the sensitivity of the
exposure estimates to key uncertainties. However, based on the discussion above, the overall
approach is expected to overestimate actual exposures for each exposure pathway.
Because so many site-specific variables affect chemical and microbial exposure from livestock
carcass management, exposures at actual sites are likely to be less than, but might be greater
than, estimated by this assessment. Based on the assessment, this Report contributes to
understanding potential chemical and microbial exposure pathways and how design and
implementation could modify exposures of humans, livestock, and wildlife. Table 7.3.4 describes
how changing some of the key aspects of design or implementation of the carcass management
options would change potential exposures.
Table 7.3.4. Effect of Scenario Design or Implementation on Potential Exposures
Management
Options(s)
Aspect of
Implementation
Effect of Change on Exposure
All on-site
options
Scale of
mortality
In general, larger mortalities result in greater potential releases and
exposures. Large scale losses could make some management options
technically infeasible or require the use of multiple options. Longer periods
of temporary carcass storage might be required, which increases the
potential for exposures.
All on-site
options
Meteorology
Effect varies by parameter. For example, the strength and uniformity of
winds determine the downwind distribution of airborne chemicals. The
frequency, amount, and intensity of rainfall affects rates of erosion surface
runoff, and chemical leaching to soil.
All on-site
options
Soil particle size
and type
Natural soils vary in texture, mineral composition, and availability of pores
or fractures of substantial size. Those factors in turn influence how quickly
leachate and rainwater can flow through soils vertically and likely it is for
chemicals and microbes to sorb to soil particles. Soils comprised of fine
particles (e.g., clay) can hold more water, but also retard flow to
groundwater and adsorb more chemicals and microbes than soils consisting
of medium (e.g., loam) or larger particles (e.g., sand). This assessment uses
recommended default soil properties fromHHRAP (USEPA 2005a), which
were chosen to reflect national average conditions.
All on-site
options
Soil organic
content
Higher organic content favors sorption of non-ionic organic chemicals (e.g.,
PAHs and dioxins/furans). It also favors sorption of microbes. In both
cases, soils with higher organic content would filter out more contaminants
than would soils with lower organic carbon content.
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Management
Options(s)
Aspect of
Implementation
Effect of Change on Exposure
All on-site
options
Surface slope
A slope of 5% was used. Lesser slopes could result in rainwater pooling
during storms but virtually no runoff or erosion. Greater slopes would result
in higher soil erosion and more rapid runoff during precipitation events. For
temporary carcass storage piles on bare ground, greater slopes could allow
faster and farther surface movement of leachate.
All on-site
options
Lake size
In general, larger lakes provide more dilution of chemicals and microbes
that reach them via surface runoff and erosion or by groundwater recharge
(see Figure 5.4.1). Small lakes or ponds could respond to added carbon,
nitrogen, phosphorus with noxious algal blooms. Small lakes also might
respond to added BOD and COD from buried carcasses with fish kills from
depleted oxygen.
All on-site
options
Home-grown
foods
This assessment assumes that farm residents eat home-grown fruits,
vegetable, meat, dairy, and eggs, as well as fish caught in the on-site lake.
Exposures will be lower for farm residents who also or exclusively
consume commercial foods (e.g., from grocery stores).
All on-site
options
Exposure
assumptions
Exposures are estimated using assumptions about the body weight and
ingestion rates (e.g., of drinking water, foods) of farm residents. The
assumptions are based on mean values for the U.S. population (USEPA
2011). Higher or lower exposures could result at sites where actual
exposure factors are different from those values.
All on-site
options except
compost
application
Groundwater
hydrology
For this assessment, groundwater carries chemicals and microbes that
originated in carcasses and that migrated to groundwater to an on-site well
and lake. In many locations, however, site-specific groundwater hydrology
can preclude these pathways. For example, contamination of the well might
be prevented by the speed or direction of groundwater flow, or the depth of
the well relative to the source. For many lakes, the direction of water flow
(recharge) is from the surface water to groundwater.
Open burning
and Air-
curtain
burning
Source
placement
relative to
receptor
locations
Public objections to open burning in the past have primarily come from the
smoke, soot, and sulfurous odors emanating from an open pyre. Air-curtain
burning produces lower levels of all three nuisances than open pyre. The
farther away from the farm residence, neighboring residences, towns and
cities, the fewer people will be affected.
Open burning
and Air-
curtain
burning
Ash disposal
For this assessment, ash is buried with clean soil on site, and leaching from
the ash can carry chemicals and microbes to groundwater. In some cases,
ash might be managed in other ways with more or less potential for
exposure. For example, less exposure would be expected if the ash is sent to
an off-site landfill. When ash is managed on site (e.g., buried, mixed
sparingly in surface soils), the configuration and placement of the
management area can affect enviromnental concentrations and potential
exposure pathways.
Air-curtain
burning
Fuel-to-carcass
ratio
Fuels used in air-curtain burners include large quantities of wood and a
relatively small amount of accelerant to start the fire. For this assessment, a
4:1 ratio of wood to carcasses is assumed. The literature suggests that
higher quality wood (e.g., drier, excluding scrap material, reasonable
diameter for combustion) would allow a 2:1 ratio, which would lower
emissions of PAHs and possibly some inorganic particles.
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Management
Options(s)
Aspect of
Implementation
Effect of Change on Exposure
Open burning
Type of coal
added
Most U.S. citizens are not aware of differences among types of coal with
respect to energy content and sulfur emissions. The two principal types of
coal mined in the United States are bituminous and subbituminous.
Bituminous coal has approximately two times the energy content per unit
weight as subbituminous. It also contains more sulfur. Tradeoffs between
odor and weight of coal added to the pyre can be a consideration for farms
with nearby neighbors or towns.
Open burning
Potential
microbial
hazards
If prions are not present in healthy livestock prior to their death in a natural
disaster, open burning could inactivate all pathogens in the carcasses. On-
site open burning would be ranked more favorably if prions are not present
in livestock carcasses.
Burial
Vertical distance
to groundwater
The burial option requires at least 1 m (3 ft) between the bottom of a burial
pit and the highest groundwater level expected over many decades (e.g., 50-
year storm event). If groundwater reaches buried carcasses, its
contamination is much more likely.
Composting
Type of bulking
material
Carbon bulking materials commonly used in composting (e.g., silage, straw,
corn stalks, woodchips) differ in their absorptive capacity and efficacy in
preventing leachate from reaching subsurface soils. Woodchips are assumed
in this assessment. Other materials might be more or less available and
more or less effective.
Composting
Potential
microbial
hazards
If prions and spore-forming bacteria are not present in healthy livestock
prior to their death in a natural disaster, carcass composting could inactivate
all of the pathogens in the carcasses. In that case, compost could be land-
applied in areas where there are other livestock and crops without the
additional "wait time" required to allow for the complete inactivation of
spore-forming bacteria and prions. Composting could be ranked more
favorably if prions and spore-forming bacteria are not present in the
livestock carcasses.
7.4. Summary of Findings, Mitigation Measures, and Research Needs
This assessment is meant to support selection of environmentally protective livestock carcass
management methods in the event of a natural disaster. The findings presented in Section 7.2
shed new light on the potential for chemical and microbial exposures from the commonly-used,
on-site carcass management options, and provide further insights into the relative contribution of
the specific exposure pathways and carcass management activities. In addition, the assessment
identifies some, but not necessarily all, of the chemicals and microbes that could be released
from livestock carcass management and how chemical and microbial properties can affect their
environmental fate and exposures.
The assessment finds that, when properly designed and implemented, the on-site carcass
management options are not estimated to cause adverse health or environmental effects. Off-site
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options, including incineration, landfilling, and rendering, are subject to air, water, and solid
waste regulations designed for adequate health and environmental protection.
Because many site-specific factors contribute to the movement of chemicals and microbes in the
environment, the exposure estimates presented in this report should not be interpreted as "actual"
exposures associated with the management options. Site managers can use the findings of this
report, in conjunction with site-specific factors, to make more informed decisions about available
carcass management options. Section 7.3 discussed some ways in which different site-specific
conditions could affect exposures relative to the scenarios evaluated.
The findings of this assessment also can support selection and priority setting for mitigation and
best management practices to minimize exposures, and to set priorities for further research.
Table 7.4.1 provides information to support these goals, including descriptions of the fate of
chemical and microbes, mitigation measures to minimize exposures, and research needs for each
option.
In addition to the mitigation measures recommended in Table 7.4.1, the following measures are
recommended for all of the livestock carcass management options following a natural disaster:
¦ State and local agencies can develop plans for handling mass livestock mortalities that are
appropriate at a county level given local hydrology, meteorology, and availability of off-site
rendering, incineration, or landfill facilities.
¦ All persons involved should follow applicable regulations and available guidance for
selecting a site, designing, and implementing carcass management units.
* Workers should wear PPE when engaged in carcass management activities.
¦ Individuals not participating in carcass management activities should have little or no direct
contact with carcasses, active management processes, or residual materials (e.g., ash).
The conceptual models, environmental and exposure modeling approaches, and supporting data
and assumptions developed for this exposure assessment constitute a significant resource for
further technical and regulatory analysis. In the next phase of the current project, the assessment
methods described in this Report will be adapted to evaluate livestock carcass management
options in the event of a FAD outbreak. The methods also will be adapted to accidental or
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intentional contamination of livestock with chemicals (e.g., pesticides) or radioactive materials.
In other research, the assumptions for managing livestock carcasses following a natural disaster
could be varied to evaluate the sensitivity of estimated exposures to those assumptions or to
evaluate the benefits of various mitigation methods or standards. The exposure estimation
methods or findings also could be used to build or refine decision support tools for site-specific
planning or response actions.
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Table 7.4.1. Summary of Livestock Carcass Management Options, Mitigation Measures, and Research Needs
Option or
Activity
Exposure Summary
Potential Mitigations
Research Needs
On-site
Combustion
¦ On-site combustion options generally are
effective at inactivating all types of microbes
(except prions) when there is an even burn at a
sufficiently high temperature.
¦ Metal in fuels and associated with carcasses are
not destroyed by combustion, and the
combustion process generates new chemical
agents of concern such as dioxins/furans and
PAHs. Both on-site combustion options are
assumed to include wood fuels, but open burning
also includes coal which introduces additional
PAHs and metals. Chemicals are either dispersed
in combustion emissions (concentrations are
highest within 1,000 meters) or retained in
"bottom" ash.
¦ Because the ash contains potentially high
concentrations of metals and persistent organic
compounds and lias a high pH, care should be
taken to manage ash appropriately.
¦ When possible, install combustion units
downwind from human, agricultural, and
enviromnental receptors, including homes,
businesses, farm buildings, crops, pastures,
and surface waters. Otherwise, install
combustion units more than 1,000 meters
from these enviromnental receptors to reduce
the potential for inhalation and deposition of
contaminants in the air.
¦ Monitor burn piles to ensure combustion
attains and maintains even heating for the
appropriate duration of time, and provide an
ample ratio of fuel to carcasses.
¦ Ash may have a high pH and contain
persistent chemicals such as metals and
PAHs. If the ash cannot be disposed of in a
commercial landfill, it could be buried or
encapsulated with clean soil. The ash should
be isolated from the root zone of plants.
¦ Wet the ash prior to burial, and minimize
other handling and processing to avoid
resuspending contaminants in the air. Do not
use the ash as a surface soil amendment.
¦ Measurement of the constituents
in emissions for open burning
and air curtain burning,
including the effect of fuel
selection and quantities on
emissions characteristics.
¦ Measurement of the combustion
temperatures within the pyre to
better understand inactivation of
resistant biological agents
including prions.
¦ Fate and transport of prions in
various media.
¦ Chemical (metals, organics,
nutrients, and veterinary drugs)
and microbial analysis of
carcass ash.
¦ Data on leaching of chemicals
from combustion ash.
¦ Monitoring well data (both
chemical and microbial) at
several distances from ash
burial sites.
On-site Burial
¦ Burial does not thermally deactivate microbial
contaminants. Most chemicals and microbes
from the carcasses adhere to soil and are not
highly mobile in an unsaturated burial site, but
leachate may carry chemicals and survival-forms
of microbes into groundwater supplies.
¦ Burial removes the land from other productive
uses, and proper site selection for the burial
trench ensures separation from the aquifer,
downgradient wells, and water bodies.
¦ Do not place burial sites up-gradient of
groundwater wells or surface water bodies;
ensure compliance with required setback
distances and other site restrictions.
¦ Comply with the minimum requirements for
depth above the water table to minimize
releases to groundwater.
¦ Properly lime the carcasses as required by the
jurisdiction.
¦ Research to characterize
microbial profile of leachate
from buried carcasses.
¦ Research to characterize the
release rates, minimal
enviromnental conditions for
survival, and fate and transport
of microbes released from
buried carcasses.
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Option or
Activity
Exposure Summary
Potential Mitigations
Research Needs
¦ If feasible, include a liner of compacted clay
in the burial trench. Ventilation shafts can be
included to facilitate escaping gases and to
maintain the integrity and effectiveness of the
cover soil.
¦ Restrict access or minimize activity at the
burial site to ensure the integrity of the cover
soil.
¦ Monitor the burial site and replenish the soil
cover as needed as carcasses decompose
beneath the surface.
¦ Systematic study to determine
survival of spore-forming
microbes and viruses during the
carcass decomposition process
¦ Monitoring data of chemical
and microbial releases to air
from burial sites.
¦ Monitoring of carcass burial
sites to gain a better
understanding of subsurface
methane release and the
potential for methane intrusion
to structures.
On-site
Composting
¦ Composting inactivates most microbes while
minimally releasing chemicals and microbes
from the windrow. With finished compost used
as a soil amendment, this option enables
beneficial recycling of nutrients and carbon.
¦ Finished compost may contain metals and
persistent organic chemicals (e.g., veterinary
drugs) that may remain in soil, be taken up by
plants, or run off to surface water.
¦ Use best practices to ensure composting
achieves recommended temperatures and time
for pathogen control.
¦ Use appropriate carbon material in a quantity
sufficient to provide adequate aeration and
adsorption of liquids.
¦ Apply adequate cover material to the
windrow to discourage potential scavengers
and other pests.
¦ Test the soil under the windrow for
acceptable levels of chemicals before growing
crops or animal feed, or for pasturing
livestock.
¦ Allow at buffer distance between the compost
application area and the nearest surface water
body
¦ Use runoff/erosion control best management
practices to prevent areas where the compost
lias been applied to soils from reaching
surface water bodies.
¦ Rapid revegetation with cover crops or native
grasses can provide erosion control.
¦ Studies of prions populations,
concentrations of metals,
veterinary drugs, and other
chemicals in finished compost.
¦ Field analysis of the fate and
transport of prions and spore-
forming microbes during
composting and following
application of compost to
surface soil.
¦ Further study of the gaseous
releases to air from the
windrow, including chemical
profile, release rates,
concentrations at various
distances, and changes in
release rate as composting
progresses.
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Option or
Activity
Exposure Summary
Potential Mitigations
Research Needs
Off-site
Options
¦ For this assessment, release of chemicals and
microbes from off-site carcass management
facilities are assumed to be from regulated
pollution control systems. These releases were
not quantified and are assumed to be controlled
to levels protective of human health and the
enviromnent.
¦ Do not allow the products of off-site carcass
management options to enter the production
stream for consumable products, such as bone
meal, if the carcasses are suspected of
containing prions.
¦ Ensure that appropriate disinfectants are used
during off-site carcass transportation and
handling.
¦ Monitoring data or studies to
assess the releases from
regulated, off-site management.
Carcass
Handling
¦ Exposures to workers are not quantified in this
assessment and are assumed to be effectively
mitigated by the use of gloves, dust masks, and
other personal protective equipment.
¦ Do not handle carcasses with bare hands,
especially after there are visible signs of
decomposition (e.g., bloating, leakage).
¦ Use appropriate personal protective
equipment (see 29 CFR 1910.120, Appendix
B) when handling carcasses, body fluids,
litter, or other potentially contaminated
materials.
¦ For a quantitative exposure
assessment, data on exposure
factors (e.g., frequency and
duration of hand contact, area of
skin exposed) for carcass
handlers, and the effectiveness
PPE or compliance with PPE
use
¦ Concentrations of chemicals
and microbes on contact
surfaces.
¦ Data on the "typical" level of
personnel protective equipment
used during carcass
management.
Temporary
Carcass
Storage
¦ For the carcass transportation and handling
activities included in the exposure assessment,
the temporary carcass storage pile is the most
likely source of exposure.
¦ Estimated exposures from leachate reaching
groundwater from the storage pile are low and
comparable to exposures from leachate from the
compost windrow.
¦ Potential exposures from the temporary storage
pile are influenced by the duration of storage, the
level of carcass decomposition and leakage, and
management practices.
¦ Locate carcass storage piles on impervious
surfaces or liners to prevent leaching to soil
and leachate flowing to groundwater. Manage
drainage to collect any leachate, leakages, or
runoff.
¦ Cover the carcass storage pile to minimize
releases of chemicals and microbes to air,
control scavengers, insects, and other pests,
and divert precipitation.
¦ Ensure adequate ventilation, particularly for
storage indoors.
¦ Monitoring of emissions to air
from the storage pile, including
chemical profile, emission rates,
concentrations at various
distances, and changes in
emissions as decomposition
progresses.
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Option or
Activity
Carcass
Transportation
Exposure Summary
Potential exposure pathways from carcass
transportation begin with liquid leakage from the
truck bed, emissions to air, and spillage in the
event of an accident.
Exposures from truck bed leakage and emissions
to air are assumed to be negligible at locations
along the transportation route, and are not
estimated.
The likelihood of truck accidents with spillage
was estimated from highway traffic safety data.
For eight truck trips of 100 km each, the risk of
an accident with spillage is estimated to be 7.1E-
05.
Potential Mitigations
Select leak-proof vehicles to transport
carcasses. Because some leakage can be
expected from vehicles designed to be leak-
proof, use of plastic liners or absorbent
material can minimize leakage.
Use a tarp or similar covering for vehicles
that are open on the top.
Load vehicles to no more than 60% capacity
by volume because carcasses may bloat and
expand in volume as decomposition
progresses.
Transport carcasses as soon as possible.
Research Needs
Further research to assess
potential exposures associated
with transporting carcasses to
off-site facilities.
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8, Qualia Assurance
The development of this report was carried out in accordance with USEPA Quality Assurance
Program. This project was approved by a designated quality assurance manager prior to the start
of any work. This project addresses all elements listed in the "EPA Requirements for QA Project
Plans, EPA QA/R-5."
An extensive review of the existing literature was an important component of this study. A
literature review was conducted to identify and collect the available peer-reviewed journal
articles, fact sheets, reports, guidance documents, and other pertinent information related to
exposure assessment of livestock carcass management options. Various sources of information
on carcass management, where mortality is due to natural disasters, were identified. The peer-
reviewed articles were downloaded after libraries were searched across key databases and other
web science searches. Technical reports released by various federal agencies and international
organizations were identified and collected. Additional vendor-supplied data, newsletters, and
fact sheets were obtained. Information included in the report was drawn primarily from peer-
reviewed publications. Peer-reviewed publications contained the most reliable information,
although some portions of the report may contain compilations of data from a variety of sources
and non-peer-reviewed literature (workshop proceedings; graduate degree theses/dissertations;
non-peer-reviewed reports and white papers from industry, associations, and non-governmental
organizations) and unpublished data (online databases, personal communications, unpublished
manuscripts, unpublished government data). Non-peer-reviewed and unpublished sources did
not form the sole basis of any conclusions presented in the report of results. Generally, these
sources were used to support results presented from peer-reviewed work, enhancing
understanding based on peer-reviewed sources, identifying promising ideas for pathway analysis
and exposure assessment, and provided discussion of tiered approach of ranking systems. The
qualitative ranking has been performed based on the review of the literature search. Secondary
data were used as per the U.S. EPA approved Quality Assurance document and review of
published or unpublished data for identifying relevant information and exposure assessment of
livestock carcasses. These secondary data included original research papers published in peer-
reviewed journals and pertinent review articles that summarize original research, obtained from
hard copies and computerized databases. However, no quality assurance (QA) (accuracy,
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precision, representativeness, completeness, and comparability) of secondary data has been
conducted. The data cited in this report were collected from published literature/fact sheets/web,
and no attempt has been made to verify the quality or veracity of data collected from various
sources.
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Appendices
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
TABLE OF CONTENTS FOR APPENDICES
Appendix A. Data for Polycyclic Aromatic Hydrocarbons A-l
A.l. PAH Emissions by Carcasses from Different Livestock Species A-2
A.2. Air Emission Factors for PAHs by Combusted Material A-5
A.2.1. Carcasses A-5
A.2.2. Wood (Open Pyre and ACB, Timbers and Kindling) A-8
A.2.3. Coal A-13
A.2.4. Straw or Hay A-18
A.3. Relative Potency Factors A-20
A.4. References Cited A-23
Appendix B. Data for Dioxins and Furans B-l
B.l. Fuel-specific Emissions Data for Dioxins and Furans B-l
B.l.l. Open Pyre Wood Burning B-2
B.l.2. Air-Curtain Burning (ACB) Wood Burning B-4
B.l.3. Open Pyre Coal Burning B-6
B.1.4. Open Pyre Straw Burning B-6
B.2. Toxicity Equivalency Factors (TEFs) for Dioxins and Furans B-7
B.3. References B-8
Appendix C. Conceptual Models C-l
C.l. Legend to Module Diagrams C-2
C.2. Conceptual Model Overviews C-4
C.3. Carcass Management Source Modules C-15
C.3.1. Abiotic Compartment Modules C-23
C.3.2. Biotic Compartment Modules C-28
Appendix D. AERMOD Supporting Information D-l
D.l. References D-15
Appendix E. Description of the HHRAP Soil and Surface Water (SSW) Screening
Model E-l
E.l. Introduction E-l
E.2. Use of HHRAP Framework E-2
E.3. Fate and Transport Modeling Outputs E-4
E.4. Parameterization E-8
E.5. References E-9
Appendix F. Detailed Parameter Documentation Tables for the HHRAP SSW
Excel™ Model F-l
F.l.Input Parameter Values F-l
F.2.Rationale for Assumed Parameter Values F-3
F.3.References F-7
App.-i
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Appendix G. Supporting Information for Chemical Leaching from Burial,
Composting, and Carcass Storage G-l
G.l. References G-l
Appendix H. Supporting Information for Chemical Leaching from Combustion
Ash H-l
H.l. References H-l
Appendix I. Supporting Information for Groundwater Recharge to Surface
Water 1-1
Appendix J. Aquatic Food Web Modeling J-l
J.l. Approach for Inorganic Chemicals J-l
J.2. Approach for Organic Chemicals J-3
J.3. References J-8
Appendix K. Documentation of the Multimedia Ingestion Risk Calculator K-l
K.l. Introduction K-l
K.l.l. Scope of MIRC K-2
K.l.2. MIRC Highlights K-2
K.2. MIRC Overview K-3
K.2.1. Exposure Pathways K-4
K.2.2. Receptor Groups K-5
K.3. Exposure Algorithms K-7
K.3.1. Farm-Raised Foods - Algorithms to Calculate Chemical
Concentrations K-8
K.3.2. Chemical Intake Calculations for Adults and Non-Infant Children . K-15
K.3.3. Calculation of Total Chemical Intake K-17
K.4. Model Input Options K-17
K.4.1. Environmental Concentrations K-18
K.4.2. Chemical Uptake into Farm Food Products K-18
K.4.3. Adult and Non-Infant Exposure Parameter Values K-36
K.4.4. Other Exposure Factor Values K-50
Appendix L. Toxicity Reference Values L-l
L.l. Benchmarks Used in Exposure Assessment (main report, Section 7) L-l
L.2. Air Concentrations—Short-term Human Health Benchmarks L-7
L.3. Benchmark Concentrations - Human Welfare L-9
L.4.Ingestion Reference Doses L-ll
L.5.Ecological Benchmarks L-14
L.5.1. Surface Water L-14
L.5.2. Soils L-15
L.6.Other Adverse Effects L-16
L.7. References L-17
App. - ii
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Appendix A. Data for Polycycli imatlc Hydrocarbons
The National Research Council (NRC) (1983) estimated 39% of annual U.S. emissions of
polycyclic aromatic hydrocarbons (PAHs) from the early to mid-1970s originated from open
burning (4,024 of the total of approximately 10,320 metric tons/yr) and 38% from residential
wood stove heating (as cited by ATSDR 1995). Peters et al. (1981) estimated 36% from open
burning, 35% from residential heating, and only 1% each from incineration and power
generation. Open burning includes controlled burns of agricultural fields to clear remaining
debris, to kill weed seeds in the surface soil, or to force new growth (e.g., berry bushes), and
uncontrolled forest and grassland fires. Lobscheid and McKone (2004) estimated that the
contribution of residential wood combustion to PAHs in air in the state of Minnesota to be on par
with those released from gasoline-powered automobiles. By comparison, the contribution of
carcass combustion to total PAH emissions to air across the United States is negligible (i.e.,
0.124 metric tons total PAHs per 453 metric tons (50 U.S. tons) of cattle burned (main report,
Table 3.3.2) compared with 10,320 metric tons PAHs released annually nationwide.
None of the materials included in the two on-site combustion scenarios, open pyre burning and
air-curtain combustion, contain PAHs initially. Combustion of carcasses and various fuels,
however, does produce PAHs in various quantities. PAHs as released in flames are primarily in
the vapor phase; however, upon cooling in ambient air, mid-to higher molecular weight PAHs
are found almost entirely in particulate material (USEPA 1998 citing Schure andNatusch 1982).
Apparently, PAHs adsorb to particle surfaces (primarily through hydrogen bonding) and might
condense to aerosol particles. In general, the highest concentrations of PAHs in air emissions are
found on the smaller diameter aerosol particles because the smaller particles have higher surface-
to-mass ratios than do larger particles (USEPA 1998 citing Natusch and Tomkins 1978).
The fuels used to burn carcasses differ for open pyre and air-curtain burning as do the average
temperatures of the burn. Several fuels generally are included to ensure a relatively complete
open pyre burn (e.g., wooden railway ties and kindling, bales of hay or straw, diesel, coal; see
main report, Section 3.2.1, Table 3.2.1), whereas only wood is needed for an air-curtain burner
(diesel exhausts from the fans used to create the air curtain are not included here). Open pyre
_
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
burning also occurs at lower temperatures (e.g., 550°C, Table 3.2.1) than air-curtain burning
(e.g., 850°C, Table 3.3.1, Section 3.3.1). To estimate emissions of PAH compounds to air, three
important assumptions were made:
1. As described in the main report, and based on literature reviewed for the exposure
assessment, PAH production and emission profiles (i.e., relative emission rates for
individual PAH compounds compared with total PAHs) from different categories of
livestock are assumed to not differ substantially.
2. As described in Section A.2.1, the relative PAH emissions in vapor and particulate phases
are assumed to be compound-specific and could be influenced by burn temperature.
3. PAH production and emission profiles, including releases to air in particulate versus
vapor phases, partitioning of PAHs to fly ash compared with bottom ash, and total PAH
and ash production, are assumed to vary by fuel type. Therefore, emissions factors (EFs)
are estimated for PAHs by compound and by fuel type in Sections A.2.2 (wood -
kindling and railway ties combined), Section A.2.3 (coal), and Section A.2.4 (hay or
straw).
To compare emissions to human health-based or other environmental-based benchmarks, the
relative potency factor (RPF) approach was used with benzo[a]pyrene (BaP) as the index
chemical (USEPA 2010a; WHO 1998). All chronic oral exposures for humans are combined into
a single benzo[a]pyrene-equivalent exposure as described in Section 5.3.2 of the main report.
Section A.3 lists compound-specific RPF values that were multiplied by the total ingestion
exposure to each PAH. The resulting BaP-equivalent oral exposures then could be added across
all of the PAHs (for which data were adequate) and compared with BaP carcinogenic potency.
A.l. PAH Emissions by Carcasses from Different Livestock Species
Data on emission of PAHs as measured by Chen et al. (2003) for hogs and other livestock from
lower and higher temperature incinerators are compared to data from U.S. Environmental
Protection Agency (USEPA) for game birds incinerated in an air-curtain burner (USEPA 2013).
This comparison suggests that the PAHs emitted in the highest quantities relative to total PAHs
A-2
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
are sufficiently similar across the studies to apply the same set of emission factors (EFs) across
different types of livestock (e.g., hogs, cattle, poultry).
Chen et al. (2003) studied emissions of PAHs from different types of incinerators, including a
hog farm waste incinerator (HOWI), which burned at 255°C to 595°C with unrefined methane
gas as the auxiliary fuel, and a livestock disease control incinerator (LIWI), which burned at a
somewhat higher temperature (755°C to 891°C) fueled by diesel. Results from the HOWI, which
Chen et al. (2003) presented as bar graphs in Figure 1 of their report, are presented in Table A.l,
with values approximated from the graphs.
Table A.l. PAH Concentrations in Emissions from Hog Incinerator and Air-curtain
Incinerator.
Hogs in Animal Waste Incinerator3
Poultry in Air curtain
.
(ug/m3)
Burner b(
Total ppb)
PAH (number ot aromatic rings)
Gaseous
Particle
Total
Percent
1 bird/10
1 bird/4
jig/m3
jig/m3
jig/m3
of Total
min
min
Naphthalene (3)
277.0
7.86
284.8
46.5%
268
786
Acenaphthylene (3)
27.7
0.34
28.04
4.6%
42.1
198
Acenaphthene (3)
6.34
0.77
7.10
1.2%
nd
J 9.7
Fluorene (3)
16.32
0.90
17.22
2.8%
J 14.7
63.3
Phenanthrene (3)
34.24
17.25
51.49
8.4%
52.3
151.1
Anthracene (3)
8.43
4.33
12.77
2.1%
J 5.16
J 33.32
Fluoranthene (4)
11.97
46.41
58.33
9.5%
27.4
71.8
Pyrene (4)
12.04
58.37
70.41
11.5%
22.7
58.0
Benzo[a]anthracene (4)
1.53
3.91
5.44
0.89%
J 4.34
J 14.21
Chrysene (4)
1.55
3.06
4.61
0.75%
J 4.31
J 13.45
Cyclopenta[c,d]pyrene (5)
0.44
0.58
1.02
0.17%
na
na
Benzo[k]fluoranthene (5)
0.65
0.19
0.84
0.14%
J 2.16
J 5.38
Benzo[b]fluoranthene (5)
1.49
1.71
3.20
0.52%
J 5.31
J 14.76
Benzo[e]pyrene (5)
2.70
3.59
6.28
01.0%
J 2.48
J6.ll
Benzo[a]pyrene (5)
1.83
0.83
2.67
0.44%
J 3.39
J 10.42
Perylene (5)
0.84
0.59
1.42
0.23%
nd
nd
Indeno[l,2,3,-cd]pyrene (6)
10.05
8.11
18.16
3.0%
J 2.44
J 5.52
Dibenzo[a,h]anthrance (6)
2.95
1.79
4.74
0.77%
nd
nd
Benzo[b]chrycene (6)
1.78
0.77
2.55
0.42%
na
na
Benzo[ghi]perylene (6)
2,94
3.47
6.41
01.0%
J 3.21
J 6.03
Coronene (7)
2.79
1.72
4.51
0.74%
na
na
Total PAHs
425
173
613.1
100%
nc
nc
Abbreviations: na = not analyzed, nc = not calculated because of uncertainty in measurements below the quantitation limit; nd =
not detected; PAH = polycyclic aromatic hydrocarbon.
Note: Shaded cells represent the PAHs released in the highest proportions; which are similar for hogs and poultry.
a Data provided by Shui-.Ten Chen, first author of Chen et al. (2003), instead of being estimated from mean values as presented in
bar graphs in Figure 1 from Chen et al. (2003), for hogs in incinerator fueled by methane from waste-treatment facility.
bUSEPA (2013). Poultry incinerated in pilot-scale air-curtain burner (refractory box) with clean wood as auxiliary fuel.
A-3
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Chen et al. (2003) found that the highest proportion of PAHs released were low molecular
weight (MW) compounds with three to four aromatic rings. As expected from physical/chemical
characteristics, releases of the smaller, low MW PAHs were primarily in vapor phase whereas
releases of the high MW PAHs were primarily in particulate phase.
In a test of a pilot-scale air-curtain burner, USEPA compared PAH emissions for Cornish game
hens (nominally 2-3 pounds per bird) loaded with two different quantities of clean wood. The
wood was added to the burner at a constant rate of 25 pounds per hour (in 1.5x 1.5x 12 inch
boards); the game hens were added at different rates from 1 bird per 10 minutes (or 25 lbs wood
per 6 birds) to 1 bird per 4 minutes (or 25 lbs of wood per 15 birds). Kansas State University
recommends wood to carcass ratios of 2:1 to 1:1 (USEPA 2013). The results for those two
conditions also are in Table A.l. Many of the measurements, however, were below the
quantitation limit (marked with a J) for the compound.
The pattern of individual PAHs recovered from the air as emitted from the birds combusted in
the air-curtain burner is similar to the pattern from the HOWI (Table A.l). The cells highlighted
in light blue in Table A.l identify those PAHs that account for more than 2% of the total mass of
PAHs. Close to half (47%) of the mass of PAH emissions from the HOWI was emitted as
naphthalene ("moth balls," which sublimates from a solid to vapor phase at ambient
temperatures). Another 35% of the total PAH mass from the HOWI came from only five other
PAHs with 3 or 4 rings. For the HOWI, over 97% of the naphthalene was released in gaseous
form. Similarly, the other 3-ringed PAHs were primarily emitted as gases rather than in
particulate form. The 4-ringed PAHs were emitted primarily in particulate form. One PAH not
conforming to the pattern for the HOWI is indeno[l,2,3-cd]pyrene, which has six rings. Its
release was approximately 3% of the total PAH mass, and a little over 50% of the chemical
measured was in vapor phase despite its high molecular weight.
To examine differences in emissions of the HOWI and the LIWI, Chen et al. (2003) grouped
PAHs according to molecular weight, with low MW containing two-to three-ringed PAHs,
middle MW containing four-ringed PAHs, and high MW containing five-, six-, and seven-ringed
PAHs. They found the gaseous concentrations of the stack flue gas to be comparable for the two
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
carcass incinerators (LIWI = 478 |ig/m3 and HOWI = 426 |ig/m3). As shown in Table A.2,
emissions from the lower burning temperature HOWI were higher than from the higher
temperature LIWI, even though the HOWI included a waste effluent scrubber.
Table A.2. Emission Quantities and Emission Factors of the Stack Flue Gas for PAHs
(Chen et al. 2003).
Emission
Emission Amount
Emission Factor
Emission Factor
PAH Group
Amount (g/day)
(percent)
(jig/kg waste)
(percent)
HOWI
LIWI
HOWI
LIWI
HOWI
LIWI
HOWI
LIWI
Low MW PAHs
29.4
11.0
78%
85%
235,000
2,435
82%
85%
Medium MW PAHs
5.66
1.05
15%
8%
34,700
234
12%
8%
High MW PAHs
2.65
0.888
7%
7%
15,600
198
5%
7%
Total PAHs
37.7
12.9
100%
100%
285,000
2,867
100%
100%
Abbreviations: HOWI = hog farm waste incinerator; LIWI = livestock disease control incinerator; MW = molecular weight;
PAH = polycyclic aromatic hydrocarbon.
A.2. Air Emission Factors for PAHs by Combusted Material
Emission profiles for PAH congeners can differ among substances combusted, combustion
temperatures, and combustion conditions (ATSDR 1995). To allow alternative assumptions on
auxiliary fuel use in response to comments, this section reports methods and original data for
calculating PAH emissions in g/s separately for carcasses (Section A.2.1), wood (Section A.2.2),
coal (Section A.2.3), and straw/hay (Section A.2.4).
A.2.1. Carcasses
All of the PAHs collected by Chen et al. (2003) are assumed to be derived from the carcasses per
se. The burn temperatures of 255°C to 595°C were close to the assumed open pyre burn
temperature of 550°C (Section 3.2). Both methane (used as the auxiliary fuel in the HOWI) and
diesel (used as the auxiliary fuel in the LIWI) should produce minimal PAHs when combusted
compared with PAHs generated due to combustion of the carcasses. Table A.l (in Section A.l
above) presents the data from Chen et al. (2003) from Figure 1 of their original report, with 613
[j,g/m3 total PAHs in both vapor and particulate phases combined. The first two data columns in
Table A. 3, present the same data as the fraction of the total PAHs in particulate and vapor phases
separately. The total PAH concentration from the particulate phase and in the vapor phase sum to
100%.
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
We calculated the emission factors for each congener, in (J,g/kg carcasses (third and fourth data
columns of Table A.3), from the fractions in Table A.3 assuming 285,000 [j,g[total
PAHs]/kg[carcasses] emitted to air (Table A.2 for HOWI). Except during wet deposition, vapor-
phase chemicals disperse farther from the source than particle-phase chemicals, which deposit
closer to the source, with distance from the source decreasing with increasing particle size.
Multiplying the fractions by 45,359 kg (i.e., 50 tons) of carcasses and dividing by 172,800
seconds (i.e., 48 hours), emission factors were estimated in g/s in particulate and vapor phases
separately (final two data columns in Table A.3). We use those values to represent the open-pyre
emissions from only carcasses.
Table A.3. PAH Emission Factors for Carcasses Combusted at Lower Temperature
Incinerators for Use in Modeling of Open Pyre Burning.
PAH (number of aromatic
rings) [acronym/acronyms]
Fraction of Total
PAHs from Hog
Carcasses
Emission Factors
(ju.g/kg carcasses)
Emission Factors (g/s)
Particle
Vapor
Particle
Vapor
Particle
Vapor
Naphthalene (3) [Nap]
1.32E-02
4.66E-01
3.77E+03
1.33E+05
9.90E-04
3.49E-02
Acenaphthylene (3) [Acy/ANL]
5.72E-04
4.58E-02
1.63E+02
1.30E+04
4.28E-05
3.42E-03
Phenanthrene (3) [Phe/PA]
2.90E-02
5.76E-02
8.27E+03
1.64E+04
2.17E-03
4.31E-03
Fluorene (3) [Flu]
1.51E-03
2.75E-02
4.32E+02
7.83E+03
1.13E-04
2.05E-03
Acenaphthene (3) [Ace/Acp/AN]
1.30E-03
1.07E-02
3.69E+02
3.04E+03
9.69E-05
7.98E-04
Anthracene (3) [Ant/AC]
7.29E-03
1.42E-02
2.08E+03
4.04E+03
5.45E-04
1.06E-03
Pyrene (4) [Pyr]
9.82E-02
2.03E-02
2.80E+04
5.77E+03
7.35E-03
1.52E-03
Chrysene (4) [Chr/CHR]
5.15E-03
2.61E-03
1.47E+03
7.43E+02
3.85E-04
1.95E-04
Fluoranthene (4) [Flt/FL]
7.81E-02
2.01E-02
2.23E+04
5.74E+03
5.84E-03
1.51E-03
Benzo[a]anthracene (4) [BaA]
6.58E-03
2.58E-03
1.88E+03
7.34E+02
4.92E-04
1.93E-04
Benzo[a]pyrene (5) [BaP]
1.40E-03
3.08E-03
3.98E+02
8.78E+02
1.05E-04
2.30E-04
Benzo[e]pyrene (5) [BeP]
6.04E-03
4.54E-03
1.72E+03
1.30E+03
4.52E-04
3.40E-04
Benzo[k]fluoranthene (5) [BkF]
2.88E-03
2.51E-03
8.20E+02
7.15E+02
2.15E-04
1.88E-04
Benzo[b]fluoranthene (5) [BbF]
2.88E-03
2.51E-03
8.20E+02
7.15E+02
2.15E-04
1.88E-04
Cyclopenta[c,d]pyrene (5) [CYC]
9.76E-04
7.41E-04
2.78E+02
2.11E+02
7.30E-05
5.54E-05
Perylene (5) [PER/Pery]
9.93E-04
1.41E-03
2.83E+02
4.03E+02
7.43E-05
1.06E-04
Dibenzo[a,h]anthrance (6) [DBA]
3.32E-03
4.97E-03
9.45E+02
1.41E+03
2.48E-04
3.71E-04
Indeno[l,2,3,-cd]pyrene (6) [IND]
1.37E-02
1.69E-02
3.89E+03
4.82E+03
1.02E-03
1.27E-03
Benzo[ghi]perylene (6) [BghiP]
5.84E-03
4.95E-03
1.66E+03
1.41E+03
4.37E-04
3.70E-04
Benzo[b]chrysene (6) [BbC]
1.30E-03
3.00E-03
3.69E+02
8.54E+02
9.69E-05
2.24E-04
Coronene (7) [COR/CO]
2.89E-03
4.70E-03
8.25E+02
1.34E+03
2.17E-04
3.51E-04
Total PAHs a
0.283
0.717
8.07E+04
2.04E+05
2.12E-02
3.49E-02
Abbreviations: PAH = polycyclic aromatic hydrocarbon; s = second.
Source: Chen et al. (2003), Hog Incinerator or HOWI, Figure 1.
a Sum of proportion vapor and proportion particulate for total PAHs (bold) = 100% or 1.0.
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
The first two data columns in Table A.4 present the fraction of the total PAHs in particulate and
vapor phases separately for the higher burn-temperature LIWI (from Figure 2 in Chen et al.
2003). The fractions of the total PAH in the particulate phase and in the vapor phase sum to
100%.
Table A.4. PAH Emission Factors for Carcasses Combusted at Higher Temperatures for
Use in Modeling of Air-Curtain Burning.
PAH (number of aromatic
Fraction of Total from
Hog Carcasses
Emission Factors
(iig/kg carcasses)
Emission Factors
(g/s)
rings) [acronym/acronyms]
Particle
Vapor
Particle
Vapor
Particle
Vapor
Naphthalene (2)
6.11E-02
5.92E-01
1.75E+02
1.70E+03
4.60E-05
4.46E-04
Acenaphthylene (3)
1.91E-03
8.41E-02
5.48E+00
2.41E+02
1.44E-06
6.33E-05
Phenanthrene (3)
3.82E-03
9.55E-02
1.10E+01
2.74E+02
2.88E-06
7.19E-05
Fluorene (3)
3.82E-03
2.10E-02
1.10E+01
6.03E+01
2.88E-06
1.58E-05
Acenaphthene (3)
3.82E-03
7.64E-03
1.10E+01
2.19E+01
2.88E-06
5.75E-06
Anthracene (3)
9.55E-04
1.91E-03
2.74E+00
5.48E+00
7.19E-07
1.44E-06
Pyrene (4)
3.82E-03
1.91E-02
1.10E+01
5.48E+01
2.88E-06
1.44E-05
Chrysene (4)
1.91E-03
7.64E-03
5.48E+00
2.19E+01
1.44E-06
5.75E-06
Fluoranthene (4)
3.82E-03
2.10E-02
1.10E+01
6.03E+01
2.88E-06
1.58E-05
Benzo[a]anthracene (4)
5.73E-04
2.87E-03
1.64E+00
8.22E+00
4.31E-07
2.16E-06
Benzo[a]pyrene (5)
9.55E-04
1.91E-03
2.74E+00
5.48E+00
7.19E-07
1.44E-06
Benzo[e]pyrene (5)
9.55E-04
2.87E-03
2.74E+00
8.22E+00
7.19E-07
2.16E-06
Benzo[k]fluoranthene (5)
9.55E-04
3.82E-03
2.74E+00
1.10E+01
7.19E-07
2.88E-06
Benzo[b]fluoranthene (5)
9.55E-04
3.82E-03
2.74E+00
1.10E+01
7.19E-07
2.88E-06
Cyclopenta[c,d]pyrene (5)
1.91E-04
6.69E-03
5.48E-01
1.92E+01
1.44E-07
5.03E-06
Perylene (5)
1.91E-03
5.73E-03
5.48E+00
1.64E+01
1.44E-06
4.31E-06
Dibenzo[a,h]anthrance (6)
9.55E-04
1.91E-03
2.74E+00
5.48E+00
7.19E-07
1.44E-06
Indeno[l,2,3,-cd]pyrene (6)
9.55E-04
3.82E-03
2.74E+00
1.10E+01
7.19E-07
2.88E-06
Benzo[g,h,i]perylene (6)
1.91E-03
3.82E-03
5.48E+00
1.10E+01
1.44E-06
2.88E-06
Benzo[b]chrysene (6)
1.91E-03
7.64E-03
5.48E+00
2.19E+01
1.44E-06
5.75E-06
Coronene (7)
1.91E-03
5.73E-03
5.48E+00
1.64E+01
1.44E-06
4.31E-06
Total PAHs a
0.099
0.901
2.84E+02
2.58E+03
7.46E-05
6.78E-04
Abbreviations: PAH = polycyclic aromatic hydrocarbon; s = second.
Source: Chen et al. (2003), Livestock Waste Incinerator or LIWI, Figure 2.
a Sum of proportion vapor and proportion particulate for total PAHs (bold) = 100% or 1.0
From those fractions and assuming 2,867 [j,g[total PAHs]/kg[carcasses] emitted to air (Table A.2
for HIWI), the emission factors were calculated in (J,g/kg carcasses (third and fourth data
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
columns of Table A.4). Multiplying those values by 45,349 kg (i.e., 50 tons) of carcasses and
dividing by 172,800 seconds (i.e., 48 hours), emission factors were estimated in g/s in particle
and vapor phase separately (final two data columns in Table A.4). Those values were input to the
AERMOD simulation of air-curtain burner (ACB) emissions from carcasses only.
A.2.2. Wot len Pyre and ACB, Timbers and Kindling)
Air EFs are estimated for PAHs released from wood from open pyres (railroad ties and wood
kindling combined) from multiple sources. PAHs released to air in particulate phase and vapor
phase from burning wood, or that reported vapor-phase emissions, are not distinguished in the
literature reviewed. Many reports evaluated the content of wood ash for use in soil amendments
(e.g., recycling in forests, Bundt et al. 2001; Sarenbo 2009; Enell et al. 2008). Studies included
different subsets of the 21 PAHs included in this appendix.
We used data from Hays et al. (2003) to estimate EFs for open-pyre burning of wood. Data
included PAH content of fine particles (PM2.5) released from residential wood combustion
(woodstove burning Douglas fir with low moisture content - 13% = WSDL[woodstove burning
Douglas fir]), and compounds containing 4 rings or more and for anthracene. Their experimental
design did not capture vapor-phase PAHs, and they did not analyze emissions for naphthalene,
acenapthylene, phenanthrene, or fluorene. Those data were supplemented with data from
Lamberg et al. (2011) who measured PAH EFs for particles of 1 |im or less (PMi) (Table A.5).
We assume the PMi includes condensed aerosols of the 2- and 3-ringed PAHs. Neither study
measured naphthalene releases.
Samples from the stack were diluted with air and flowed through an insulated line externally
heated to 150°C (i.e., 302°F) (Lamberg et al. 2011). The fourth data column in Table A.5
presents the average of the three units in ng/mg, with the next column presenting results in
|ig[PAH]/kg[PMl], To allow extrapolation of the 3-ring PAH data from the Lamberg et al.
(2011) study to the 3-ring PAHs not sampled by Hays et al. (2003), we calculated an average
concentration of each 3-ring PAH to the concentration of benzo[a]pyrene (Table A.5, final
column).This approach assumes similar emission profiles across the two studies, which is
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
reasonable considering the similar fuel types and burn temperatures. Omitting the 3-ring PAHs
because they were not analyzed by Hays et al. (2003) would be misleading.
Data from Hays et al. (2003) are presented in the first four data columns of Table A.6. The ratios
of the 3-ring PAHs to BaP from Lamberg et al. (2011), presented in the last column of Table
A.5, were multiplied by the BaP emission rate from Hays et al. (2003), in the fourth column of
Table A.6, to estimate the EFs in g/s for 3-ring PAHs that might have been released (final data
column Table A.6). For anthracene, measured by both groups, the estimated EFs are different by
about one half-order of magnitude. The values listed in bold in Table A.6 were used to estimate
EFs to air from all wood (i.e., 36,000 kg) used to burn 50 tons of cattle in an open pyre.
Table A.5. PAH Air Emission Factors for Wood/Kindling Added to Open Pyre.
PAH (number of aromatic
rings)
ng[PAH]/mg[PMl] particles
Avgof 3
Ratio
Avg 3
CB/Avg
BaP
CB1
CB2
CB3
Avg of 3
CB
CBs
(Mg/kg)
Acenaphthylene (3)
51.1
129.3
11.9
64.1
0.064
0.0402
Phenanthrene (3)
2317
5370
1061
2916
2.916
1.83
Fluorene (3)
90
334
34.6
152.9
0.153
0.0970
Acenaphthene (3)
1.6
3.5
1.4
2.17
0.002
0.00136
Anthracene (3)
483.7
955.7
227
555.5
0.555
0.349
Pyrene (4)
2742
3200
2578
2840
2.840
nr
Chrysene (4)
907
1201
909
1006
1.006
nr
Fluoranthene (4)
2835
3476
2187
2833
2.833
nr
Benzo[a]anthracene (4)
1004
1397
1052
1151
1.151
nr
Benzo[a]pyrene (5)a
1149
2002
1628
1593
1.593
nr
Benzo[e]pyrene (5)
525
801
600
642
0.642
nr
Benzo[k]fluoranthene (5)
783
1208
860
950.3
0.950
nr
Benzo[b]fluoranthene (5)
1120
868
657
881.7
0.882
nr
Cyclopenta[c,d]pyrene (5)
2150
1991
1954
2032
2.032
nr
Perylene (5)
153
255
217
208.3
0.208
nr
Dibenzo[a,h]anthrance (6)
49.5
156.3
122
109.3
0.109
nr
Indeno[l,2,3,-cd]pyrene (6)
507
924
704
711.7
0.712
nr
Benzo[ghi]perylene (6)
669
1051
925
881.7
0.882
nr
Benzo[b]chrysene (6)
na
na
na
na
na
na
Coronene (7)
421.8
419
245
361.9
0.362
nr
Abbreviations: CB = combustion burner; na = not analyzed; nr = not relevant - not calculated or used; PAH = polycyclic
aromatic hydrocarbon; PM1 = particles of 1 (im or less.
Source: Lamberg et al. (2011).
a Benzo[a]pyrene value, shaded in light blue, used as divisor to calculate ratios in final data column.
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Table A.6. PAH Air Particulate Emission Factors for Wood and Kindling Added to Cattle
Open-Pyres.
PAH (number of aromatic
rings)
Dry Weight
Wood Burned
(mg/kg)
Total PAHs
released
(mg)
EFs (mg/s)
(Hays et al.
2003)
EFs (g/s)
(Hays et al.
2003)
Estimated
EFs (g/s)a
Naphthalene (2)
na
na
na
na
na
Acenaphthylene (3)
na
na
na
na
1.21E-06
Phenanthrene (3)
na
na
na
na
5.52E-05
Fluorene (3)
na
na
na
na
2.90E-06
Acenaphthene (3)
na
na
na
na
4.11E-08
Anthracene (3)
0.0107
341
1.975E-03
1.98E-06
1.05E-05
Pyrene (4)
0.0469
1496
8.658E-03
8.66E-06
nr
Chrysene (4)
0.0973
3103
1.796E-02
1.80E-05
nr
Fluoranthene (4)
0.0501
1598
9.248E-03
9.25E-06
nr
Benzo[a]anthracene (4)
0.1046
3336
1.931E-02
1.93E-05
nr
Benzo[a]pyrene (5)
0.1635
5215
3.018E-02
3.02E-05
nr
Benzo[e]pyrene (5)
0.1027
3276
1.896E-02
1.90E-05
nr
Benzo[k]fluoranthene (5)
0.0909
2899
1.678E-02
1.68E-05
nr
Benzo[b]fluoranthene (5)
0.0909
2899
1.678E-02
1.68E-05
nr
Cyclopenta[c,d]pyrene (5)
na
na
na
na
na
Perylene (5)
0.0238
759
4.393E-03
4.39E-06
nr
Dibenzo[a,h]anthrance (6)
0.0082
261
1.514E-03
1.51E-06
nr
Indeno[l,2,3,-cd]pyrene (6)
0.0895
2854
1.652E-02
1.65E-05
nr
Benzo[ghi]perylene (6)
0.0457
1457
8.436E-03
8.44E-06
nr
Benzo[b]chrysene (6)
0.0057
181
1.052E-03
1.05E-06
nr
Coronene (7)
0.0202
644
3.729E-03
3.73E-06
nr
Abbreviations: EF = emission factor; na = not analyzed; nr = not relevant - not calculated or not used (use Hays et al. 2003
value); PAH = polycyclic aromatic hydrocarbon; PM1 = particles of 1 (im or less; s = seconds.
Source: Hays et al. (2003) Table 3, WSDL, which means woodstove burning Douglas fir, 13% moisture content.
a Estimated EFs based on Hays et al. (2003) value for BaP and ratios of chemical to BaP from Lamberg et al. (2011).
In the absence of data distinguishing vapor-phase from particle-phase PAHs for wood burning,
we assume that all of the PAHs released from wood burning in an open pyre would be in
particulate phase and, therefore, could deposit closer to the source than would vapor-phase
PAHs. We also assumed PM2.5 instead of PM10, because PAH concentrations on smaller ash
particles are higher than PAH concentrations on larger particles (higher surface to mass ratio)
and because PM2.5 penetrate deeper into the lungs than PM10.
We used Sarenbo's (2009) measurements of PAHs released from industrial boilers in Sweden
powered by burning wood (Table 4 in Sarenbo 2009) to estimate PAH emissions from burning
wood in an air-curtain pit at higher temperatures than in open pyres. Wood used as fuel was first
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
pulverized, burned once, and then the ash was reburned, which reduced the organic carbon
content from 40% to 5%.
To estimate emissions of fly ash per kg of wood burned, we converted the wood added (4:1 ratio
of wood to carcass biomass) into the total weight of fly ash released to air. For 45,359 kg of
carcasses, we estimate 181,437 kg of wood required. Assuming the wood to be 12% water
(typical value for woods used in stoves, boilers), 88% of the original mass of wood added (i.e.,
159,664 kg) is burnable. According to Lamberg et al. (2011), 0.4% of the dry weight of birch
logs is ash, with moisture ranging from 10 to 13%. For the air curtain burner (ACB) burn, we
assume that the relatively high temperature of the burn eliminated the moisture and combusted
almost all of the remaining materials to total (fly and bottom) ash.
To apportion the ash between fly and bottom ash, we used data from Narodoslawsky and
Obernberger (1996). To evaluate heavy metal content of wood ash produced by wood-burning
facilities in Austria, they estimated the proportion of ash emitted to air and caught on filters and
the proportion remaining as bottom ash. Using a multi-cyclone filter and a filter fly-ash
precipitator, they captured 15—25% of the initial weight of wood chips burned as cyclone fly ash
and 1-4%) as filter fly ash, with the remainder 75-85%) of the initial biomass retained in the
bottom ash. The bottom ash fell through the bottom grate at initial temperatures of 500-1000°C;
the cyclone filter was installed after the heat exchanger and therefore operated at approximately
140-200°C. Based on the ranges of cyclone and filter fly ash from wood chips reported by
Narodoslawsky and Obernberger (1966), we assume 78% of wood added to the ACB pit remains
as bottom ash while 22% is emitted to air as fly ash. That means that 650 kg of bottom ash
remains and 140 kg of ash is emitted to air for an ACB combustion of 50 tons of cattle. Table
A.7Table A.7 lists the average concentration of PAHs in the fly ash emitted from the first burn as
measured each week for 9 weeks (i.e., 9 samples from the same boiler).
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Table A.7. PAH Air Emissions for Wood added to Air-Curtain Burning (ACB) of
Carcasses (based on Sarenbo 2009), Particule-Phase Only.
PAH (number of aromatic
rings)
Concentrations in Wood Fly Ash (mg/kg)
Total
EF (g/s)
Particles
Average
SD
Min
Max
PAH
(mg)
Naphthalene (2)
69
23
44
120
9.69E+03
5.61E-05
Acenaphthylene (3)
28
11
17
55
3.93E+03
2.28E-05
Phenanthrene (3)
20
7.8
10
38
2.81E+03
1.63E-05
Fluorene (3)
0.23
nd
0.23
0.23
3.23E+01
1.87E-07
Acenaphthene (3)
nd
nd
nd
nd
0
0
Anthracene (3)
1.9
1
0.66
4.3
2.67E+02
1.54E-06
Pyrene (4)
14
5.7
7.9
28
1.97E+03
1.14E-05
Chrysene (4)
1.0
0.66
0.38
2.7
1.41E+02
8.13E-07
Fluoranthene (4)
12
5.0
6.5
24
1.69E+03
9.76E-06
Benzo[a]anthracene (4)
0.82
0.55
0.27
2.2
1.15E+02
6.67E-07
Benzo[a]pyrene (5)a
1.5
0.97
0.54
3.9
2.11E+02
1.22E-06
Benzo[e]pyrene (5)
0.605 a
na
na
na
8.49E+01
4.92E-07
Benzo[k]fluoranthene (5)
0.96
0.65
0.33
2.6
1.69E+02
9.76E-07
Benzo[b]fluoranthene (5)
1.2
0.59
0.5
2.6
1.35E+02
7.81E-07
Cyclopenta[c,d]pyrene (5)
na
na
na
na
na
na
Perylene (5)
2.10 a
na
na
na
2.95E+02
1.71E-06
Dibenzo[a,h]anthrance (6)
1.1
0.7
0.37
2.8
1.55E+02
8.94E-07
Indeno[l,2,3,-c,d]pyrene (6)
3.2
1.9
1.3
7.7
4.50E+02
2.60E-06
Benzo[g,h,i]perylene (6)
0.083
0.036
0.05
0.13
1.17E+01
6.75E-08
Benzo[b]chrysene (6)
na
na
na
na
na
na
Coronene (7)
2.0 a
na
na
na
2.83E+02
1.64E-06
Abbreviations: EF = emission factor; na = not analyzed; nd = not detected; PAH = polycyclic aromatic hydrocarbon; PM1 =
particles of 1 (im or less; s = seconds; SD = standard deviation.
Source: Values based on Sarenbo (2009).
a Value based on ratios to BaP released as estimated from Lamberg et al. (2011), although higher bum temperature might result
in different ratios.
Presumably, additional quantities of naphthalene and the 3-ringed PAHs were released that
remained in vapor phase. We did not attempt to correct the emissions in Table A.7 to account for
vapor-phase PAHs, which would disperse quickly away from the burn location. However,
estimates of benzo[e]pyrene (BeP), perylene, and coronene that might have been released in
particulate phase (toxic and likely to deposit locally) are based on the ratios of those chemicals
released from wood as reported by Lamberg et al. (2011).
To estimate emissions of fly ash per kg of wood burned, we converted the wood added (4:1 ratio
of wood to carcass biomass) into the total weight of fly ash released to air. For 45,359 kg of
carcasses, we estimate 181,437 kg of wood required. Assuming the wood to be 12% water
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
(typical value for woods used in stoves, boilers), 88% of the original mass of wood added (i.e.,
159,664 kg) is burnable. According to Lamberg et al. (2011), 0.4% of the dry weight of birch
logs is ash, with moisture ranging from 10 to 13%. For the ACB burn, we assume that the
relatively high temperature of the burn eliminated the moisture and combusted almost all of the
remaining materials to total (fly and bottom) ash.
To apportion the ash between fly and bottom ash, we used data from Narodoslawsky and
Obernberger (1996). To evaluate heavy metal content of wood ash produced by wood-burning
facilities in Austria, they estimated the proportion of ash emitted to air and caught on filters and
the proportion remaining as bottom ash. Using a multi-cyclone filter and a filter fly-ash
precipitator, they captured 15—25% of the initial weight of wood chips burned as cyclone fly ash
and 1-4%) as filter fly ash, with the remainder 75-85%) of the initial biomass retained in the
bottom ash. The bottom ash fell through the bottom grate at initial temperatures of 500-1000°C;
the cyclone filter was installed after the heat exchanger and therefore operated at approximately
140-200°C. Based on the ranges of cyclone and filter fly ash from wood chips reported by
Narodoslawsky and Obernberger (1966), we assume 78% of wood added to the ACB pit remains
as bottom ash while 22% is emitted to air as fly ash. That means that 650 kg of bottom ash
remains and 140 kg of ash is emitted to air for an ACB combustion of 50 tons of cattle.
To estimate the total PAH quantities (mg) released to air during ACB combustion of cattle
carcasses (Table A.7, Total PAH column), the concentrations of PAHs in the wood fly ash (first
data column in Table A.7) were multiplied by the total of 140 kg of ash released to air. Dividing
the totals released by 172,800 seconds (i.e., 48 hours), and converting units to grams, the final
EFs were estimated for particle-phase PAHs in g/s (final data column of Table A.7).
A.2.3. Coal
In the United States, coal from eastern states (e.g., Ohio, Pennsylvania, and parts of West
Virginia) has higher sulfur content, accounting for 3—10% of the coal's weight (i.e., bituminous
and anthracite coal). Coal from western states (e.g., Wyoming, Montana, Utah, Colorado,
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Alaska) can have sulfur contents that make up less than 1 percent of its weight (e.g., low sulfur
subbituminous coal).19
Most of the coal mined in the United States is subbituminous and bituminous. Bituminous coal
has a carbon content of 45-80% and provides approximately twice the energy per unit weight
than subbituminous coal. Subbituminous coal, with a carbon content of 35-45%, is younger in
age, contains more moisture and volatile chemicals, and is more alkaline than bituminous coal.
Bituminous coal is generally used to generate electricity or converted to coke for use in the steel
industry at facilities with pollution controls that can reduce sulfur emissions as well as reduce
particulate emissions. Without post-combustion emission controls, it generates a yellowish foul-
smelling smoke, with relatively larger particle size distributions. Because of the relatively high
sulfur content of bituminous coal, many power plants are switching to low-sulfur subbituminous
coal from the western states, even though twice as much is required and transportation costs can
be higher. Less than 10% of the coal mined in the United States is anthracite, and that is found
only in Pennsylvania. U.S. anthracite coal has a high sulfur content, in contrast to Chinese
anthracite coal which has a low sulfur content.
USD A guidance does not specify what type of coal should be added to carcasses for open pyre
burning (i.e., "coal used as fuel should be of good quality," USDA 2005, page 12). Coal quality
rankings generally correspond to the energy content per unit weight, with the top grade of coal
being anthracite (> 90% carbon), then bituminous (45-80%) carbon), then subbituminous (35-
45%), and finally lignite (< 40% carbon). Higher energy content correlates with higher non-
volatile carbon content and lower moisture content. Lower sulfur content also is desirable to
minimize odors and yellowish smoke. The concentration of sulfates is higher in salt water than in
fresh water; therefore coal with high-sulfur content is formed from compression of organic
matter predominantly from brackish and salt-water wetlands, whereas low-sulfur coal originates
from freshwater bogs (NRC 1993). Thus, sulfur content can vary independently of carbon
content in coal.
"http://www.sourcewatch.org/index.php/Sulfur dioxide and coal#cite note-18
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Many investigators have studied low sulfur anthracite and bituminous coal emissions to air from
residential coal stoves in China, where coal is a popular residential fuel (Chen et al. 2004, 2005;
Liu et al. 2009, 2012; Zhi et al. 2008); few have examined coal emissions from residential stoves
in the United States, where use of coal in homes is rare. We calculated emissions of PAHs from
the burning of coal added as an auxiliary fuel to the open pyre combustion scenario from
measured emissions for Chinese residential combustion of honeycomb coal briquettes (Chen et
al. 2004). That study was selected because temperatures for residential coal burning are lower
than for coal-fired power plants (for which USEPA data are available), and therefore more
appropriate and similar to open pyre coal burning. In addition, Chen et al. (2004) used a series of
filters to measure particle sizes associated with the emitted PAHs after dilution and cooling in
ambient air. Initially, all PAHs released from a burn at 125°C (257°F, residential fire box) are in
vapor phase (Chen et al. 2004). After dilution with ambient air and cooling, a higher proportion
of the lighter molecular weight PAHs remain in the gas phase, while the heavier PAH
compounds condense more into aerosols and onto fine particles.
Chen et al. (2004) sampled and analyzed PAHs in emissions in a high efficiency stove with the
air-control valve fully opened (i.e., highest burn temperature possible for the stove). They
captured initial emissions using a large hood and large mixing chambers to simulate dilution with
ambient air. From those chambers, a long narrow curved pipe submerged in water cooled the
emissions to approximately 23-25°C. Those emissions were segregated by particle size using a
multi-filter sample. The first filter, with a mesh size of 7.2 |im, captured larger particles. A series
of filters with smaller mesh pores (i.e., 3.0, 1.5, 0.95, and 0.49 |im) captured smaller particles.
The proportion of total PAHs removed by the pre-filter was less than 2%, with the exception of
phenanthrene for which 7.44% was retained on the pre-filter. Only 7-10% of fluorene and
phenanthrene were in the 3.0-7.2 |im particle range. Approximately 51-16% of the total mass of
PAHs remained in vapor phase or sorbed to particles less than 0.49 |im (the final filter). The
mass mean aerodynamic diameter (MMAD) ranged from 0.39 to 0.44 |im (Table 6 in Chen et al.
2004). Based on those findings, we assume all particle-phase PAHs are associated with fine
particles (i.e., PM2.5 or smaller).
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Larger particles (e.g., > PM2.5) could deposit closer to the source. They would, however, have a
lower content of sorbed PAH than smaller particles, because of the lower surface to mass ratio
for larger particles. Given that we are not assessing carcinogenic risks from PAH exposure via
inhalation (48 hour exposure is negligible comparable with a 70-year lifetime for which cancer
potency factors are calculated), our assumption is that the bulk of PAH deposition to ground, and
possible chronic exposures that might result from subsequent ingestion of soils and crops, is
associated with PM2.5 or smaller.
Table A.8 lists the reported emission factors for residential anthracite coal combustion in
|ig[PAH]/kg[coal] for vapor-phase, particulate, and total PAH (|ig/kg) from Chen et al. (2004).
Table A.8. PAH Air Emission Factors from Residential Coal Combustion Used in Open-
Pyre Model.
Coal Emission Factors (g
PAH/sec) for 5 Tons Coal/48
Hours
Particles Vapor Total
Naphthalene (2)
na
na
na
na
na
na
na
Acenaphthylene (3)
0.003
0.748
0.75
99.7
7.87E-11
1.96E-08
1.97E-08
Phenanthrene (3)
0.064
82.086
82.15
99.9
1.68E-09
2.15E-06
2.16E-06
Fluorene (3)
0.069
4.622
4.691
98.5
1.81E-09
1.21E-07
1.23E-07
Acenaphthene (3)
nd
0.534
0.534
100
0
1.40E-08
1.40E-08
Anthracene (3)
0.002
2.031
2.034
99.9
5.25E-11
5.33E-08
5.34E-08
Pyrene (4)
0.075
4.34
4.415
98.3
1.97E-09
1.14E-07
1.16E-07
Chrysene (4)
0.696
1.441
2.138
67.4
1.83E-08
3.78E-08
5.61E-08
Fluoranthene (4)
0.004
8.215
8.219
100
1.05E-10
2.16E-07
2.16E-07
Benzo[a]anthracene (4)
0.073
0.144
0.2178
66.3
1.92E-09
3.78E-09
5.70E-09
Benzo[a]pyrene (5)
0.171
nd
0.171
nd
4.49E-09
0
4.49E-09
Benzo[e]pyrene (5)
1.71
0.145
1.857
7.8
4.49E-08
3.81E-09
4.87E-08
Benzo[k]fluoranthene (5)
1.02
0.178
2.2
7.4
2.68E-08
4.67E-09
3.14E-08
Benzo[b]fluoranthene (5)
1.02
0.178
2.2
7.4
2.68E-08
4.67E-09
3.14E-08
Cyclopenta[c,d]pyrene (5)
na
na
na
na
na
na
na
Perylene (5)
na
na
na
na
na
na
na
Dibenzo[a,h]anthrance (6)
0.591
nd
0.591
nd
1.55E-08
0
1.55E-08
Indeno[l,2,3,-cd]pyrene (6)
0.829
nd
0.829
nd
2.18E-08
0
2.18E-08
Benzo[g,h,i]perylene (6)
1.097
nd
1.097
nd
2.88E-08
0
2.88E-08
Benzo[b]chrysene (6)
na
na
na
na
na
na
na
Coronene (7)
1.119
nd
1.119
nd
2.94E-08
0
2.94E-08
Total PAHs
8.543
105
119
nr
nr
nr
2.97E-06
Abbreviations: na = not analyzed; nd = not detected; nr = not reported; PAH = polycyclic aromatic hydrocarbon; PM1 = particles
of 1 (im or less; s = seconds; SD = standard deviation.
Source for first four data columns, Chen et al (2004); source for last three columns, data from first four columns converted to g/s
assuming a 48-hr bum and 5 tons of coal.
PAH (number of aromatic
rings)
Emissions Coal Combustion3 (jig
PAH/kg coal)
Particles Vapor
% Vapor
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To convert those EFs to units of g[PAH]/second (g/s) of combustion for input into AERMOD
particulate dispersion modeling, the initial emissions data were multiplied by 5 tons of coal (i.e.,
4,536 kg coal), divided by 48 hours (i.e., 172,800 s), divided by 1,000,000 (|ig/g). Naphthalene
was not analyzed because it remains almost entirely in vapor phase even after mixing with
ambient temperature air and because its toxicity is low. Emission factors in g/s for particle-phase
and for vapor-phase PAHs are inputs for AERMOD's simulation of open pyre burning of 50 tons
of cattle with the auxiliary fuels specified in Section 3.1.1 of the main report.
Data from Chen et al. (2004) for anthracite coal reflect full open flue burning, with an abundance
of oxygen. We assume that condition is representative of an open pyre burn, with oxygen intake
from all sides. Most studies of residential heaters are based on "as operated" at lower
temperatures (resulting in less complete combustion) to allow longer burns at moderate
temperatures.
A limitation of using data from Chen et al. (2004) is that overall emissions from different types
of coal (e.g., anthracite, bituminous) can differ substantially. Total PAH emissions from
anthracite coal (0.117 mg/kg) in the high-efficiency stove fueled studied by Chen et al. (2004)
produced substantially lower emissions than reported for other sources. Specifically, Chen and
colleagues reported higher PAH emissions from coal briquettes (101 mg/kg), lignite (436
mg/kg), subbituminous (2,137 mg/kg) and bituminous coal (3,848 mg/kg) as burned in
residential stoves with air intake regulated at lower levels to reduce burn temperature (Table 5 in
Chen et al. 2004). Power plants burning bituminous coal at much higher temperatures emit PAHs
at lower levels (e.g., approximately 0.55-0.57 mg/kg for bituminous coal; Table 5 in Chen et al.
2004). The authors do not specify presence or absence of pollution control equipment.
Presumably, open burning of subbituminous coal yields lower emissions of PAHs than
bituminous coal, with total PAHs of between 0.6 mg[PAHs]/kg coal (bituminous coal burned at
higher temperature in power plant] and 2,200 mg[PAHs]/kg coal (subbituminous coal burned at
lower temperatures in residential stoves).
We assume that open pyre burning of anthracite coal at somewhat higher temperatures and with
ample oxygen supply might have similar PAH emissions as those reported by Chen et al. (2004).
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However, investigating other sources suggested that we had underestimated PAH emissions from
coal in open pyres. Using USEPA estimates of emissions from anthracite coal used in residential
space heaters (AP-42, Table 1.2-5, 1996 update20) would result in higher PAH emissions to air
by one or two orders of magnitude depending on the congener. For uncontrolled residential coal
boilers and furnaces combusting bituminous or subbituminous coal, USEPA (AP-42 1998
update2, Table 4.1-6) estimated EFs (in |ig/kg coal) approximately three orders of magnitude
higher than the values listed in Table A.8. Comparison is hampered, however, because USEPA
(AP-42, 1998 update2) provided estimates to a single significant digit and grouped several PAH
congeners together (e.g., benzopyrenes with perylene, anthracene with phenanthrene, all
benzofluoranthenes together). Yang et al. (2016) found that total PAH emission factors (in
mg/kg) from coal and wood combustion in industrial boilers correlate well with benzo[a]pyrene
EFs (correlation coefficient r2 of 0.9991; four types of fuel compared). USEPA (AP-42, 1998
update2) did not report benzo[a]pyrene emissions alone, however, so BaP comparisons could not
be made.
We conclude that PAH emissions from 5 tons of coal might be 100 to 1000 times higher than the
emission factors calculated by Chen et al. (2004) for anthracite coal. Multiplying the PAHs from
coal by 1000, and then dividing by a 70-yr lifetime for carcinogenic effects of PAHs, the
underestimate is a factor of 14 for the relative risk analyses in Section 7 of the main report.
A.2.4. Straw or Hay
To estimate EFs for bales of hay added to open pyres, we used data from similar materials,
including various types of "straw" left over in or from agriculture (e.g., rice, wheat, other grain
crops, corn stover). EPA's Emissions of Organic Air Toxics from Open Burning (USEPA 2002a)
provided estimates of total PAH emissions from burning of straw; however, USEPA did not
distinguish particle- from vapor-phase chemicals as needed in AERMOD. Therefore, we used
data from Zhang et al. (2011) to estimate the distribution of PAHs among particle- and vapor-
phase releases.
20 Technology Transfer Network Clearinghouse for Inventories & Emissions Factors: Emissions Factors &AP 42,
Compilation of Air Pollutant Emission Factors. Retrieved 6/25/2016 from https://www3 .epa. gov/ttnchie l/ap42/
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Zhang et al. (2011) estimated EFs for PAHs released from combustion of corn, rice, and wheat
straw, measuring both particle and vapor phases along with particle size distributions (Table
A.9). The total PAH EFs for rice, corn, and wheat were 5.26, 1.74, and 1.37 mg/kg, respectively.
Particle size distributions peaked at 0.10, 0.15, and 0.15 |im, respectively. Graphs of the size
distribution of particles from fresh smoke and steady-state releases indicated that all particles
were smaller than 1 |im (i.e., PMi). The purpose of their study was to estimate total agricultural
crop field burning to ambient air PAH concentrations in China; therefore, they did not analyze
air samples for several of the 21 PAHs covered in this appendix, and several PAHs included as
analytes could not be detected given their sampling techniques (see Table A.9). In addition, some
proportion of the PAHs detected appear to have been omitted from the PAH totals (Zhang et al.
2011, Table 1, last row).
Total PAHs emitted for three types of straw and for corn stover, as reported by USEPA (USEPA
2002a, Table 3-2), are listed in the first four data columns of Table A. 10. An average EF was
calculated across all four types of agricultural residues (fifth data column Table A. 10). We
estimated EFs separately for vapor and particulate emissions to use with AERMOD to simulate
open-pyre burning by multiplying the vapor fraction estimated from Zhang et al. (2011) (final
column in Table A.9) by the average EF in Table A. 10 (USEPA 2002a). For analytes that were
not detected in the vapor phase or were not analyzed by Zhang et al. (2011), we assume that the
total PAH concentration reported by USEPA (2002a) is in the particle phase for AERMOD
simulation of deposition particle-phase chemicals will deposit to surface water and soil closer to
the source and in greater concentrations than vapor-phase chemical.
To estimate EFs in g/s from 6,000 kg of straw added to the pyre to burn 45,359 kg (i.e., 50 tons)
of cattle, the EFs for vapor and particulate PAHs (mg[PAH]/kg[straw]), the final two columns of
Table A. 10, were multiplied by 6,000 kg to estimate the total released (first two data columns in
Table A. 11). Those values divided by 172,800 seconds (i.e., 48 hours) provided EFs for open
pyre burning in g/s. The EFs used to simulate PAH releases from straw added to open pyres are
listed in the final two columns of Table A.l 1. The higher emissions of PAHs to air from straw
despite the lower quantity of straw burned overall compared with wood might result from
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Table A.9. PAH Air Emission Factors from Straw Burning (mg/kg burned, USEPA 2002a)
Converted to EFs (mg/kg) for Vapor-phase and Particle-Phase Chemicals Separately.
PAH (number of aromatic Total Vapor and Particles (mg/kg) Calculated (mg/kg)
rings)
Barley
Corn
Rice
Wheat
Average
V
P
Naphthalene (2)
80.3
4.48
8.39
196.19
72.34
71.62
0.7234
Acenaphthylene (3)
11.75
0.40
1.06
1.50
3.678
3.368
0.310
Phenanthrene (3)
17.35
1.61
1.54
4.09
6.148
2.664
3.484
Fluorene (3)
2.70
0.12
0.36
0.32
0.875
0.553
0.322
Acenaphthene (3)
9.31
0.66
0.31
0.17
2.613
1.375
1.238
Anthracene (3)
3.00
0.19
0.27
1.07
1.133
0.496
0.636
Pyrene (4)
3.58
0.77
0.35
2.47
1.793
0.299
1.494
Chrysene (4)
1.43
0.27
0.17
1.37
0.810
0.198
0.612
Fluoranthene (4)
2.30
0.80
0.45
3.93
1.870
0.321
1.549
Benzo[a]anthracene (4)
1.13
0.19
0.15
1.30
0.693
0.1910
0.5015
Benzo[a]pyrene (5)
0.78
9.56
0.08
0.41
2.708
0.7736
1.934
Benzo[e]pyrene (5)
1.01
11.26
0.11
0.59
3.243
0
3.243
Benzo[k]fluoranthene (5)
2.40
4.66
0.15
1.14
2.088
0
2.088
Benzo[b]fluoranthene (5)
0.60
2.85
0.10
0.48
1.008
0.2290
0.779
Cyclopenta[c,d]pyrene (5)
na
na
na
na
na
na
na
Perylene (5)
0.23
2.08
0.02
0.44
0.693
0
0.6925
Dibenzo[a,h]anthrance (6)
0.01
0.57
nd/na
nd/na
0.290
0
0.29
Indeno[l,2,3,-cd]pyrene (6)
0.59
9.67
0.06
0.67
2.748
0
2.748
Benzo[ghi]perylene (6)
0.52
0.57
0.04
1.05
0.545
0.2543
0.2907
Benzo[b]chrysene (6)
na
na
na
na
na
na
na
Coronene (7)
na
na
na
na
na
na
na
Abbreviations: na = not analyzed; nd = not detected; P = particle-phase; PAH = polycyclic aromatic hydrocarbon; V = vapor-
phase.
virtually all of the emissions from straw being released to air in submicron sized particles and
vapor, with essentially none remaining in bottom ash. As reported by Zhang et al. (2011),
particles released to air from burning of dry straw are essentially all less than 1 |im in diameter.
Straw is not added to air-curtain burning units; so we do not calculate EFs for higher temperature
burning of straw.
A.3. Relative Potency Factors
The exposure assessment used RPFs for PAH compounds to evaluate exposures to PAHs as a
group (WHO/IPCS 1998; USEPA 1993, 2002a, 2002b, 2010a; USEPA SAB 2011). The RPFs
express the carcinogenic potency of each compound relative to the potency of the index PAH,
BaP, given their similarities in mode of action. Several PAH compounds are now considered
unlikely to be carcinogenic. Those are represented in Table A. 11 by low RPFs (i.e., 0.001).
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Table A.10. Estimated PAH Air Emission Factors from Burning 6,000 kg Straw in Open
Pyre.
PAH (number of aromatic
rings)
Total Releases from 6,000 kg Straw
Emission Factors
vapors (g/pyre)
particles
(g/pyre)
vapors (g/s)
particles (g/s)
Naphthalene (2)
429.7
4.34
2.49E-03
2.51E-05
Acenaphthylene (3)
20.2
1.86
1.17E-04
1.08E-05
Phenanthrene (3)
15.984
20.90
9.25E-05
1.21E-04
Fluorene (3)
3.316
1.93
1.92E-05
1.12E-05
Acenaphthene (3)
8.250
7.43
4.77E-05
4.30E-05
Anthracene (3)
2.977
3.82
1.72E-05
2.21E-05
Pyrene (4)
1.793
8.96
1.04E-05
5.19E-05
Chrysene (4)
1.190
3.67
6.89E-06
2.12E-05
Fluoranthene (4)
1.923
9.30
1.11E-05
5.38E-05
Benzo[a]anthracene (4)
1.146
3.01
6.63E-06
1.74E-05
Benzo[a]pyrene (5)
4.641
11.60
2.69E-05
6.72E-05
Benzo[e]pyrene (5)
0
19.46
0
1.13E-04
Benzo[k]fluoranthene (5)
0
12.53
0
7.25E-05
Benzo[b]fluoranthene (5)
1.374
4.67
7.95E-06
2.70E-05
Perylene (5)
0
4.16
0
2.40E-05
Dibenzo[a,h]anthrance (6)
0
1.74
0
1.01E-05
Indeno[l,2,3,-cd]pyrene (6)
0
16.49
0
9.54E-05
Benzo[ghi]perylene (6)
1.526
1.74
8.83E-06
1.01E-05
Abbreviations: PAH = polycyclic aromatic hydrocarbons; s = second.
As of June 2016, USEPA is reevaluating several PAH mixtures for its Integrated Risk
Information System (IRIS) based on workshop recommendations (USEPA 2002b).21 USEPA
might also reevaluate the cancer slope factor for BaP, currently 7.3 per mg/kg-day, given its
Science Advisory Board's recommendations (USEPA SAB 2011). The RPF approach is similar
to the toxic equivalency approach (TEQ) for non-cancer effects of dioxins (USESPA 2010b).
Table A. 11 lists the RPFs for PAHs used in the assessment of livestock carcass management
options and their sources.
21 https://cfbub.epa.gov/ncea/iris2/chemicalLanding.cfm?substance nmbr= 1033
A-21
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Table A.ll. Relative Potency Factors for PAHs.
PAH (number of aromatic
rings)
RPF
Source of RPF
Naphthalene (2)
NR
Not relevant, as a vapor, disperses and does not settle out
Acenapthylene (3)
0.001
Nisbet and LaGoy (1992) and Malcolmn and Dobson (1994) from
USEPA (2010a draft for SAB Review)
Phenanthrene (3)
0.001
Nisbet and LaGoy (1992) and Malcolmn and Dobson (1994) from
USEPA (2010a draft for SAB Review)
Fluorene (3)
0.001
Nisbet and LaGoy (1992) and Malcolmn and Dobson (1994) from
USEPA (2010a draft for SAB Review)
Acenaphthene (3)
0.001
Nisbet and LaGoy (1992) and Malcolmn and Dobson (1994) from
USEPA (2010a draft for SAB Review)
Anthracene (3)
0.3
Clement (1988, 1990); Muller et al. (1997); Larsen & Larsen (1998)
from USEPA (2010a draft for SAB Review)
Pyrene (4)
0.001
Nisbet and LaGoy (1992) and Malcolmn and Dobson (1994) from
USEPA (2010a draft for SAB Review)
Chrysene (4)
0.03
Larsen and Larsen (1998); Muller et al. (1997) from USEPA (2010a
draft for SAB Review)
Fluoranthene (4)
0.05
Larsen and Larsen (1998) from USEPA (2010a draft for SAB Review)
[more conservative than others]
Benzo[a]anthracene (4)
0.1
USEPA 1993 in USEPA 2010a
Benzo[a]pyrene (5)
1
By definition of index chemical
Benzo[e]pyrene (5)
0.007
Clement (1990), most conservative value in USEPA 2010a
Benzo[b)]fluoranthene (5)
0.1
USEPA 1993 in USEPA 2010a
Benzo[k]fluoranthene (5)
0.1
USEPA 1993 in USEPA 2010a
Cyclopenta[c,d]pyrene (5)
0.02
Larsen and Larsen (1998) in USEPA (2010a) middle of the road
Perylene (5)
0.001
Malcolmn and Dobson (1994) from USEPA (2010a draft for SAB
Review)
Dibenz[a,h]anthracene (6)
0.1
Malcolmn and Dobson (1994) from USEPA (2010a draft for SAB
Review)
Indeno[l,2,3-cd] pyrene (6)
0.1
USEPA 1993 in USEPA 2010a
Benzo[g,h,i]perylene (6)
0.02
Larsen and Larsen (1998), Clement (1988, 1990); some others higher
some others lower by 10%
Benzo[b]clirysene (6)
Not available
Coronene (7)
0.001
Malcolmn and Dobson (1994) from USEPA (2010a draft for SAB
Review)
Abbreviations: NR = not reported; PAH = polycyclic aromatic hydrocarbon; RPF = relative potency factor.
A-22
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
A.4. References Cited
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Natusch DFS, Tomkins BA. (1978). Theoretical consideration of the adsorption of polynuclear
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USEPA (U.S. Environmental Protection Agency) (1993). Provisional Guidance for Quantitative
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Appeii
The materials used in open pyre burning and air-curtain combustion may or may not initially
contain dioxins and furans. The process of combusting carcasses and various fuels, however,
might produce dioxins and furans.
Measurement of dioxins/furans released from on-site burning is complicated by their ubiquitous
presence in the environment (usually at low concentrations), including in top soils. In addition,
on-site burning operations typically do not have a conventional stack that allows accurate
measurement of emissions per unit volume. Heated soils under an open pyre or around an air-
curtain pit can release a fraction of the initially soil-bound dioxin/furan compounds to air during
combustion (Black et al. 2012a,b). Thus, unless investigators attempt to distinguish dioxin/furan
releases from the materials burned from releases of vapor-phase dioxins/furans from heated soils,
the relative contribution of each source is unknowable. Therefore, we ascribe the measured
dioxin/furan releases from materials burned on the ground to the putative material burned (e.g.,
straw, wood) (Section B. 1), and not the carcasses themselves or their placement on the ground.
To compare dioxin emissions to human health-based or other environmental-based benchmarks,
the toxic equivalency approach (TEF) approach (USEPA 2010) combined data for all congeners
relative to 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD), the index chemical (Section
B.2).
B.l. Fuel-specific Emissions Data for Dioxins and Furans
The fuels used to burn carcasses differ for open pyre and air-curtain burning as does the average
temperature of the burn. Several fuels generally are included to ensure an open pyre burn (e.g.,
wooden railway ties and kindling, bales of hay or straw, diesel, or coal), whereas only wood is
needed for an air-curtain burner (diesel exhausts from the fans used to create an air curtain are
not included here). Open pyre burning also occurs at lower temperatures than air-curtain burning.
In this assessment, we use 550°C and 850°C for each, respectively.
Dioxin/furan emissions generated from livestock carcasses are not reported, therefore, we
assume dioxin/furan congeners are not released from the carcasses. The fraction of dry matter in
B-l
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
the carcasses (e.g., 30-35%; Hanna 2010; Lohman 1971; Malone et al. 1987, cited in CAST
2008) is substantially less than the fraction dry matter in the auxiliary fuel particularly wood.
Omission of emissions from carcasses should not affect estimates of exposures to dioxins/furans
or the ranking of carcass management options.
The 17 different toxic dioxin/furan congeners with chlorine substitutions at the 2,3,7, and 8
positions emitted from combustion partition to varying degrees between vapor- and particle-
phases in ambient air. Therefore we sought congener-specific emission data for each type of
auxiliary fuel used for on-site burning. We assume that the total for released dioxins/furans came
from the fuels, and did not attempt to factor in releases that might result from heated soils. We
assume that the relative emissions in vapor and particle phase could be compound-specific and
influenced by burn temperature.
If dioxin emissions were reported only on the basis of total toxicity equivalency factors (i.e.,
TEFs or TEQs) instead of by congener, we did not apportion the emissions to individual
congeners. Some investigators reported the results only as total TEFs using congener-specific
values from WHO/IPCS (1998) that differ slightly from those currently recommended by
USEPA (2010).
B.l.l. Open Pyre Wood Burning
We estimated emissions factors (EFs) in g/s for dioxins/furans from the addition of wood to open
pyres by using the congener-specific measurements reported by Wunderli et al. (2000) for
combustion of native wood as used for residential heating in wood stoves (not waste wood from
demolition). They plotted the distribution of measured concentrations (ng/kg) in fly ash particles
in Figure 2 of their report (n = 6 samples). Our estimate of the median values from the Figure 2
histograms are listed in Table B. 1 (first data column in ng/kg[ash]). Mean values would have
been prefereable (Section 5.2.3 of main report), but Figure 2 plotted only the minimum and
maximum measurements along with the 10th, 50111, and 90th percentiles. Owing to the similarity in
the names of the polychlorinated dibenzo-p-dioxins (CDDs) and polychlorinated dibenzofurans
(CDFs), with different locations of chlorine atoms, we include the CAS Registry Number in
Table B.l.
B-2
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Table B.l. Dioxin/Furan Concentrations in Wood Fly Ash from Open Burning, 2,3,7,8-
TCDD-Toxic Equivalency Factors, and Air Emission Factors (g/s).
Compound
CAS Reg.
Number
ng/kg
[ash]
TEF
(EPA)
ng[TEF]/
kg [Ash]
%
Total
TEQ
Particle
(g/s)
%a
Part
icles
Vapor
(g/s)
OctaCDD,
1,2,3,4,6,7,8,9-
3268-87-9
19.00
0.0003
5.7E-03
0.251
2.8E-11
95
1.5E-12
OctaCDF,
1,2,3,4,6,7,8,9-
39001-02-0
5.50
0.0003
1.6E-03
0.07
8.2E-12
96
3.4E-13
HeptaCDD,
1,2,3,4,6,7,8-
35822-46-9
8.00
0.01
8.0E-02
3.53
1.2E-11
84
2.3E-12
HeptaCDF, 1,2,3,4,6,7,8-
67562-39-4
1.70
0.01
1.7E-02
0.75
2.5E-12
84
4.8E-13
HeptaCDF, 1,2,3,4,7,8,9-
55673-89-7
0.35
0.01
3.5E-03
0.15
5.2E-13
84
9.9E-14
HexaCDD, 1,2,3,4,7,8-
39227-28-6
0.70
0.1
7.0E-02
3.09
1.0E-12
63
6.1E-13
HexaCDF, 1,2,3,4,7,8-
70648-26-9
0.50
0.1
5.0E-02
2.20
7.4E-13
59
5.2E-13
HexaCDD, 1,2,3,6,7,8-
57653-85-7
0.80
0.1
8.0E-02
3.53
1.2E-12
63
7.0E-13
HexaCDF, 1,2,3,6,7,8-
57117-44-9
0.23
0.1
2.3E-02
1.01
3.4E-13
59
2.4E-13
HexaCDD, 1,2,3,7,8,9-
19408-74-3
1.00
0.1
1.0E-01
4.41
1.5E-12
63
8.7E-13
HexaCDF, 1,2,3,7,8,9-
72918-21-9
0.45
0.1
4.5E-02
1.98
6.7E-13
59
4.7E-13
PentaCDD, 1,2,3,7,8-
40321-76-4
0.70
1
7.0E-01
30.9
1.0E-12
27
2.8E-12
PentaCDF, 1,2,3,7,8-
57117-41-6
1.10
0.03
3.3E-02
1.45
1.6E-12
32
3.5E-12
HexaCDF, 2,3,4,6,7,8-
60851-34-5
0.70
0.1
7.0E-02
3.09
1.0E-12
59
7.2E-13
PentaCDF, 2,3,4,7,8-
57117-31-4
1.20
0.3
3.6E-01
15.9
1.8E-12
32
3.8E-12
TetraCDD, 2,3,7,8-
1746-01-6
0.55
1
5.5E-01
24.2
8.2E-13
16
4.3E-12
TetraCDF, 2,3,7,8-
51207-31-9
0.80
0.1
8.0E-02
3.53
1.2E-12
24
3.8E-12
Total TEF
nr
2.2b
nr
2.3°
100%
nr
nr
nr
Abbreviations: s = second; TEF = toxic equivalency factors; TEQ = toxic equivalents; nr = not summed, not relevant.
a Proportion (i.e., percent) 2,3,7,8-substituted dioxins and furans in particle phase (USEPA 2003, Table 3-4, p 3-65) from air
monitoring data published by Eitzer and Hites (1989) and Eitzer (1989). The proportion released in vapor phase in hot flue is
higher than after cooling and mixing with ambient air.
b Total TEF in ng[TEQ]/kg[fly ash] as reported by Wunderli et al. (2000, Figure 2) for native wood.
0 Total TEF as the sum of values in the same column (ng[TEF]/kg[fly ash]). Values in column are calculated from values in the
first data column (ng[chemical]/kg[fly ash]) multiplied by TEFs (USEPA 2010) in second data column.
Wunderli et al. (2000) included the median value (50th percentile) total TEF estimate (i.e., 2.2
ng/kg) based on WHO/IPCS (1998) TEQ values in their Figure 2. To confirm the reading of
Figure 2 and that the researchers used the current recommended USEPA (2010) TEF values
instead of older WHO recommendations, the concentration of each congener in ash reported by
the Wunderli group (Table B.l, first data column) was multiplied by USEPA's (2010) TEFs
(Table B.l, second data column) to estimate ng[TEF]/kg[fly ash] (Table B.l, third data column).
The sum of the estimates of median TEF concentrations (i.e., 2.3 ng/kg, Table B.l) were similar
B-3
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
to the median total (i.e., 2.2 ng/kg) in Figure 2 plotted by Wunderli et al. (2000), even though
median (not mean) values were summed. The percent was calculated of the total fly ash TEQ of
2.3 ng/kg represented by each congener (Table B. 1, fourth data column) and confirmed they
summed to 100%. The calculations of the distribution of dioxins/furans in the fly ash appear
consistent with the data.
To estimate emission rates in g/sec, we assume 36,000 kg of wood (railroad ties plus kindling)
were burned. With an initial moisture content of 12%, the mass of dry wood burned would be
31,900 kg. Based on a report by NAEI (2003), Watkiss and Smith (2001) assumed emission
factors for PMio from combustion of wood sleepers and wood kindling in an open pyre to be 7.9
g/kg. Assuming that all of the fly ash captured by Wunderli et al. (2000) was 10 |im or less in
diameter, a fly ash release rate was estimated of 8 g[fly ash]/kg[wood]. That value is consistent
with the assumptions for open pyre burning: the proportion of the dry weight of native wood
comprised of ash was 0.02; the proportion of ash remaining as bottom ash was 0.645; and the
proportion emitted as fly ash was 0.355. Thus, an estimated total of 257 kg of fly ash was
released from wood in the open pyre.
The emission rate in g/s for particle-bound dioxins/furans (Table B.l, fifth data column) equals
the total fly ash (257 kg) multiplied by the concentration of each congener in fly ash (Table B.l,
first data column) divided by 172,800 seconds for a 48-hour burn (including unit conversion of
1.0E-09 ng/kg).
The estimated vapor-phase dioxins/furans released from open pyre burning of wood is based on
USEPA's draft summary of the proportion of each dioxin and furan found in particle phase
across six different monitoring studies (USEPA 2003). The data were summarized by the number
of chlorine substitutions and whether the compound was a dioxin or furan. Those values are
listed in Table B.l (second to last data column). Using those estimates of particle- and vapor-
phase partitioning, we calculated EF values for vapor-phase congeners released from open
burning of wood after cooling and mixing with air (Table B.l, final data column).
B.1.2. Air-Curtain Burning (ACB) Wood Burning
To estimate congener-specific emissions of dioxins and furans to air from wood burning in an
air-curtain burner (ACB) pit we used data from USEPA's National Center for Environmental
B-4
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Assessment (NCEA) Database of Sources of Environmental Releases of Dioxin-like Compounds
in the United States (Version 3.0) Reference Years 1987 and 1995 (USEPA 2012).22 Industrial
wood-fired furnaces were used to be consistent with the higher temperatures reached in an ACB
pit than in an open pyre (USEPA did not present EFs for dioxins/furans for residential wood
combustion). The data, from 1987 and 1995, are prior to the requirements for dioxin-emissions
reduction that followed the 1998 World Health Organization and USEPA's assessment of human
health risks from dioxins. We assumed, therefore, that the emission rates, reported in
ng/kg[wood fuel] represent high-temperature combustion without post-combustion emission
controls for dioxins. We assume the sampled emissions were in particle-phase and calculated
additional EFs for vapor-phase dioxins using the same procedure as for Table B.l (open pyre).
Combustion of 50 tons (45,359 kg) of cattle would require four times (4x) the quantity of fresh
wood (181,437 kg) added. Assuming 12% moisture, that quantity would equal 160,000 kg dry
wood. Because the original data are in units of ng chemical released per kg wood fuel, it is not
necessary to estimate the total fly ash produced to calculate EFs. The final EFs in g/s for
particulate and vapor-phase dioxins/furans input to AERMOD to simulate ACB combustion of
50 tons of cattle carcasses are in the final columns of Table B.2.
The congener-specific EFs in g/s for particulate and vapor-phase emissions for the ACB burn
(Table B.2) are higher than those estimated for the open pyre burn (Table B. 1) by 1.5 to 2.5
orders of magnitude in large part because of the higher quantity of wood assumed to be added to
the ACB than to the open pyre. The 4:1 ratio of wood to carcasses assumed here is based on
Table 3.2.1 of the main report, Section 3.2.1 and is based on communications from the 5th
International Symposium on Animal Mortality Management held October 1, 2015, in Lancaster,
Pennsylvania.
22 Average emission factor in ng/kg wood processed, with non-detects set to zero (data also presented for non-
detects = level of detection but not used here). The difference in releases using zero and using !/2 the LOD for
non-detects is considered negligible, resulting in 0.5952 ng TEQ/kg wood and 0.6157 ng TEQ/kg wood,
respectively.
B-5
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Table B.2. Dioxin/Furan Emission Factors from Industrial Wood Burning, 1987 and 1995
(ng/kg wood) (USEPA 2012), and Emission Factors (g/s) for ACB Combustion of 50 tons of
Carcasses.
Compound
CAS Reg.
Number
EF ng/kg
[wood]a
EF total ng
/burn
Particle
(g/s)
Percent
Particle b
Vapor
(g/s)c
OctaCDD,
1,2,3,4,6,7,8,9-
3268-87-9
3.33E+00
6.04E+05
3.50E-09
95
1.84E-10
OctaCDF,
1,2,3,4,6,7,8,9-
39001-02-0
6.74E-01
1.22E+05
7.08E-10
96
2.95E-11
HeptaCDD,
1,2,3,4,6,7,8-
35822-46-9
7.45E-01
1.35E+05
7.83E-10
84
1.49E-10
HeptaCDF, 1,2,3,4,6,7,8-
67562-39-4
1.06E+00
1.93E+05
1.11E-09
84
2.12E-10
HeptaCDF, 1,2,3,4,7,8,9-
55673-89-7
1.13E-01
2.06E+04
1.19E-10
84
2.27E-11
HexaCDD, 1,2,3,4,7,8-
39227-28-6
1.15E-01
2.09E+04
1.21E-10
63
7.12E-11
HexaCDF, 1,2,3,4,7,8-
70648-26-9
3.75E-01
6.80E+04
3.94E-10
59
2.74E-10
HexaCDD, 1,2,3,6,7,8-
57653-85-7
1.38E-01
2.51E+04
1.45E-10
63
8.52E-11
HexaCDF, 1,2,3,6,7,8-
57117-44-9
4.18E-01
7.58E+04
4.39E-10
59
3.05E-10
HexaCDD, 1,2,3,7,8,9-
19408-74-3
3.21E-01
5.82E+04
3.37E-10
63
1.98E-10
HexaCDF, 1,2,3,7,8,9-
72918-21-9
1.78E-01
3.24E+04
1.87E-10
59
1.30E-10
PentaCDD, 1,2,3,7,8-
40321-76-4
7.90E-02
1.43E+04
8.29E-11
27
2.24E-10
PentaCDF, 1,2,3,7,8-
57117-41-6
4.06E-01
7.37E+04
4.27E-10
32
9.07E-10
HexaCDF, 2,3,4,6,7,8-
60851-34-5
1.92E-01
3.49E+04
2.02E-10
59
1.40E-10
PentaCDF, 2,3,4,7,8-
57117-31-4
3.89E-01
7.06E+04
4.08E-10
32
8.68E-10
TetraCDD, 2,3,7,8-
1746-01-6
3.97E-02
7.20E+03
4.17E-11
16
2.19E-10
TetraCDF, 2,3,7,8-
51207-31-9
6.84E-01
1.24E+05
7.18E-10
24
2.27E-09
Total
nr
5.59E-01
1.01E+05
5.87E-10
100
6.29E-09
Abbreviations: ACB = air-curtain burner; EF = emission factors; s = second; nr = not relevant.
a Data from 1987 and 1995 as reported in EPA/NCEA Dioxin Database (USEPA 2012) in ng/kg wood processed; assumed
releases quantified were in particle-phase.
k Proportion (i.e., percent) dioxins and furans in particle phase (USEPA 2003).
0 Vapor-phase EFs calculated from previous two data columns.
B.1.3. Open Pyre Coal Burning
There are no reports on dioxin/furan emissions from burning coal in an open pyre identified in
the available literature, which likely reflects the lack of information on the type of coal most
likely burned and the relatively small quantity of coal in comparison with wood and carcasses.
B.1.4. Open Pyre Straw Burning
For open-pyre burning of straw-like materials, we identified one secondary source that reported
emissions in units of mg[TEQ]/kg[straw burned] (USEPA 2002 citing Gullett and Touati 2002).
For rice straw and wheat straw, USEPA (2002) reported EFs of 5.37E-07 and 4.52E-07
B-6
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
mg[TEQ]/kg, respectively apparently by using the WHO/IPCS 1998 TEQs to calculate combined
dioxin/furan emissions. We assume all of those emissions were in the particulate phase to allow
more deposition closer to the source than would occur if some of the congeners were emitted in
part in vapor phase.
For open-pyre burning of 50 tons of cattle, we assume 6,000 kg of straw/hay bales are added,
with the burn lasting 48 hours (172,800 seconds). Including a unit conversion from mg to g, the
rice and wheat straw emission factors would equal 1.86E-11 and 1.57E-11 g[WH098TEQ]/s.
The average of those two values is 1.72E-11 g[WH098TEQ]/s. In the absence of congener-
specific data, to estimate dispersion and deposition using AERMOD, we assume all emissions
are particulate phase 2,3,7,8-TCDD.
B.2. Toxicity Equivalency Factors (TEFs) for Dioxins and Furaiis
The exposure assessment used TEFs for dioxin and furan congeners to estimate total exposure to
these chemicals as a group. The TEFs express the toxic potency of each congener relative to the
index chemical 2,3,7,8-TCDD. We list the TEFs for each of the 17 toxic congeners in Table B. 1
in Section B.l and in Table B.3. Some agencies and investigators use the acronym TEQ (e.g.,
World Health Organization) instead of TEF to refer to Toxicity Equivalency factors.
The TEF for the index chemical is by definition equal to 1.0. The resulting 2,3,7,8-TCDD-
equivalent oral exposures can then be added across the dioxin/furan congeners and compared
with the reference dose for 2,3,7,8-TCDD.
B-7
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Table B.3. Toxicity Equivalency Factors for Dioxins/Furans.
Compound
CAS Reg. Number
TEF (USEPA)
OctaCDD, 1,2,3,4,6,7,8,9-
3268-87-9
0.0003
OctaCDF, 1,2,3,4,6,7,8,9-
39001-02-0
0.0003
HeptaCDD, 1,2,3,4,6,7,8-
35822-46-9
0.01
HeptaCDF, 1,2,3,4,6,7,8-
67562-39-4
0.01
HeptaCDF, 1,2,3,4,7,8,9-
55673-89-7
0.01
HexaCDD, 1,2,3,4,7,8-
39227-28-6
0.1
HexaCDF, 1,2,3,4,7,8-
70648-26-9
0.1
HexaCDD, 1,2,3,6,7,8-
57653-85-7
0.1
HexaCDF, 1,2,3,6,7,8-
57117-44-9
0.1
HexaCDD, 1,2,3,7,8,9-
19408-74-3
0.1
HexaCDF, 1,2,3,7,8,9-
72918-21-9
0.1
PentaCDD, 1,2,3,7,8-
40321-76-4
1
PentaCDF, 1,2,3,7,8-
57117-41-6
0.03
HexaCDF, 2,3,4,6,7,8-
60851-34-5
0.1
PentaCDF, 2,3,4,7,8-
57117-31-4
0.3
TetraCDD, 2,3,7,8-
1746-01-6
1
TetraCDF, 2,3,7,8-
51207-31-9
0.1
Abbreviations: CAS = Chemical Abstracts Service; TEF = toxic equivalency factor; CDD = chlorinated dibenzodioxins; CDF =
chlorinated dibenzofurans.
Source: USEPA(2010).
B.3. References
Black RR, Meyer CP, Yates A, et al. (2012a). Release of PCDD/PCDF to air and land during
open burning of sugarcane and forest litter over soil fortified with mass labelled PCDD/PCDF.
Atmospheric Environment 59: 125-130.
Black RR, Meyer CP, Touati A, et al. (2012b). Emission factors for PCDD/PCDF and dl-PCB
from open burning of biomass. Environ International 38: 62-66.
CAST (Council for Agricultural Science and Technology) (2008). Poultry Carcass Disposal
Options for Routine and Catastrophic Mortality. Issue Paper 40. Ames, Iowa.
Gullet B, Touati A (2002). PCDD/F emissions from agricultural field burning. Organohalogen
Compounds 56: 135-138. Cited as Gullet and Touati (2002b) by USEPA (2002).
B-8
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Eitzer, BD, Hites RA (1989). Polychlorinated dibenzo-p-dioxins and dibenzo-furans in the
ambient atmosphere of Bloomington, Indiana. Environ Sci Technol 23: 1389-1395. Cited in
USEPA (2003).
Eitzer BD, Hites RA (1988). Vapor pressures of chlorinated dioxins and dibanzofurans. Environ
Sci Technol 22: 1362-1364. Cited in USEPA (2003).
Hanna SS (2010). Estimation of carcass composition of sheep, goats, and cattle by the urea
dilution technique. Pakistan Journal of Nutrition 9(11): 1107-1112.
Lohman TG (1971). Biological variation in body composition. Journal of Animal Science 32:
647-653.
Malone, G. W., W. W. Saylor, M. G. Ariza, K. M. Lomax, and C. R. Kaifer. 1987. Acid
preservation and utilization of poultry carcasses resulting from mortality losses. Pp. 13-16. In
Progress through Research and Extension 1987. Report 11. University of Delaware, College of
Agricultural Sciences, Newark, Delaware. As cited by CAST 2008.
NAEI (National Atmospheric Emissions Inventory) (2003). UK Emissions of Air Pollutants 1970
to 2001. As cited by Watkiss and Smith (2001).
USEPA (U.S. Environmental Protection Agency) (2002). Emissions of Organic Air Toxics from
Open Burning. Research Triangle Park, NC: Office of Research and Development, Report no.
EP A-600/R-02-076.
USEPA (2003). Exposure and Human Health Reassessment of 2,3,7,8-Tetrachlorodibenzo-p-
Dioxin (TCDD) and Related Compounds. NAS Review Draft. Washington, DC: U.S.
Environmental Protection Agency, Office of Research and Development, National Center for
Environmental Assessment, Exposure Assessment and Risk Characterization Group, December.
EPA/600/P-00/001 Cb. Accessed October 5, 2015 at
http://cfpub.epa.gov/ncea/iris drafts/dioxin/nas-review/index.cfm.
USEPA (2010). Recommended Toxicity Equivalence Factors (TEFs) for Human Health Risk
Assessments of 2,3,7,8-Tetrachlorodibenzo-p-dioxin andDioxin-Like Compounds. U.S.
Environmental Protection Agency, Risk Assessment Forum, Washington, DC. EPA/600/R-
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
10/005. Retrieved October 23, 2015 from: http://www2.epa.gov/sites/production/files/2013-
09/documents/tefs-for-di o\in-epa-00-r-10-005-final.pdf.
USEPA (2012). Database of Sources of Environmental Releases of Dioxin-like Compounds in
the United States (Version 3.0) Reference Years 1987 and 1995. National Center for
Environmental Assessment (NCEA). EPA/600/C-01/012, March 2001, WHO 98 TEQ Data
button; Summary of Source Categories, Combustion Sources of CDD/CDF, Wood Combustion,
Industrial Wood Combustion.
Watkiss P, Smith A (2001). CBA [Cost Benefit Analysis] of Foot and Mouth Disease Control
Strategies: Environmental Impacts. London: Harwell, Didcot, Oxen. AEA Technology
Environment, Report no. ED51178001.
WHO/IPCS (World Health Organization International Programme on Chemical Safety) (1998).
Selected Non-heterocyclic Policyclic Aromatic Hydrocarbons. United Nations Environment
Programme. Environmental Health Criteria 202. Accessed on Feb 2, 2016, from
http://www.inchem.org/documents/ehc/ehc/ehc202.htm.
Wunderli S, Zewnnegg M, Dolezal IS, et al. (2000). Determination of polychlorinated dibenzo-
p-dioxins and dibenzo-furans in solid residues from wood combustion by HRGC/HRMS.
Chemosphere 40: 614-649.
B-10
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
tV'r111'-r[dfit
Conceptual Models Outline
1. Legend to Module Diagrams
2. Conceptual Model Overviews
3. Detailed Source and Compartment Modules
a. Source Modules
b. Abiotic Environmental Compartment Modules
c. Biotic Environmental Compartment Modules
c-i
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters — Appendices
C.l. Legend to Module Diagrams
Boxes with rounded corners are for Abiotic Environmental Media (e.g., air, surface soil, Groundwater)
Square-corner boxes within an Environmental Medium depict an environmental "phase" (e.g., vapor,
solid/particulate, aqueous) within the Environmental Medium and are color coded (white or "clear"
for gases, light orange for soil and sediment particles, and light blue for ground and surface water).
; Square-corner boxes with a dashed outline indicates the dominant phase for the Environmental
J Medium (e.g., water or aqueous phase is the dominant phase in the surface water column whereas
; solids/particles are the dominant phase in sediments, with pore water occupying less volume).
Blue italic labels indicate the transport/transfer process associated with an arrow from one
medium/phase to another, with the width of the arrow suggesting the relative magnitude of the
process > ^
^ Black dashed arrows indicate vapor phase chemicals, blue arrows indicate
water vapor, and orange arrows indicate particulate phase agents
Open arrow indicates human transport processes
l>
Connections to other Environmental Medium modules are indicated in this type of box.
f
Boxes like this are soil or sediment
N
compartments
J
r~
Boxes like this are surface water
compartments
C-2
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters — Appendices
Green ovals represent plants, including crops, forage for livestock,
and wildlife, and other plants
Tan ovals represent animals, i.e., humans, livestock, and wildlife.
Some types are receptors of concern whereas others are part of a
food chain leading to receptors of concern
Source boxes with gradient shading represent materials placed at carcass management site to
implement the actions
Red boxes represent carcass and waste management facilities, processes, or supporting
equipment
Blue boxes with gradient shading represent treatment residuals or waste streams
C-3
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters — Appendices
C.2. Conceptual Model Overviews
Livestock Carcass Management Option
Figure
On-site Open Burning (pyre)
C.l
On-site Air-curtain Burning
C2
Off-site Fixed-facility Incineration
C.3
On-site Unlined Burial
C.4
On-site Composting
C.5
Off-site Lined Landfill
C.6
Rendering
C.7
Temporary Carcass Storage
C.8
Carcass Handling
C.9
Carcass Transportation
CIO
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters — Appendices
Natural Disaster
On-site Transportation
Mortalities
Combustion j
Open Burning
Air
Panicle
Deposition.
S tomato! Uptake
Wet & Dry Panicle
Deposition;
Diffusive Vapor
Exchange
Terrestrial
Plants
floor uptake
Inhalation
Ingestion
livestock
Incidental
Ingestion
Ingestion
Burial af ash
in pla ce
Wet & Dry
Deposition
Crosion
& Runoff
leaching
Uptake,
bioaccumulation
Surface Water
Recharge
Sedimen lotion.
Retuspension, St
Diffusive Exchange
Uptake,
bioocctimulotion
^^*U|lwllV
Aquatic
Life
ingestion &
inhalation
Well
Water
Ingestion
\ Humans )•*
Ingestion
inhalation
Figure C.l. On-site Open Burning
C-5
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters — Appendices
Natural Disaster
On-site Transportation
Mortalities
Combustion
Air
Particle
Deposition,
Stomatal Uptake
Air Curtain Burning
Wet & Dry Particle
Deposition;
Diffusive Vapor
Exchange
Burial of ash
in place
Wet& Dry
Deposition
Terrestrial
Plants
Ingestion
Root uptake
inhalation
Incidental
Ingestion
Ingestion
Erosion
& Runoff
Leaching
Uptoke,
biooccuntulation
Surface Water
Recharge
Sedimentation,
Resuspenvon, &
Diffusive Exchange
Aquatic
Life
Uptake,
biooccumulotion
Ingestion &
Inhalation
Well
Water
Ingestion
Humans
Ingestion
Inhalation
Figure C.2. On-site Air-curtain Burning
C-6
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters — Appendices
Natural Disaster
Mortalities
D//-sj'fe TranSpartQtkm
CAA Permitted Emissions
Off-site
Ash Disposal
RCRA Subtitle D
Incineration
Landfill
k- -J
Air
Particle Deposition,
Stommal Uptake
Terrestrial \ Hoot uptake
Wet & Dry
Particle
Deposition;
Diffusive Vapor
Exchange
Wet & Dry
Deposition
CWA Permitted
Effluent Discharge
Aquatic
life
Runoff
Erosion &
Uptake,
bioaccumulatkm
Sedimentation,
Resuspensian, &
Diffusive Exchange
Inhalation
Uptake,
biaaccumutalian
Incidental
Ingestion
Ingestion
Livestock
Ingestion
Ingestion
Humans
Inholotion
Figure C.3. Off-site Incineration
C-7
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters — Appendices
Natural Disaster
On-site Transportation
Mortalities
Diffusion through cover soil
On-site Burial
Air
teaching from to
subsurface SO# and
Groundwater
Stomatal Uptake
Terrestrial
Plants
frjftafofiwi
Ingest son
Livestock
Subsurface Soil
Leaching
Surface Water
Recharge
Groundwater
Ingestion
Uptake,
bioaccuifnilation
Sedimentation,
Resuspension, &
Diffusive Exchange
Aquatic
Life
Uptake,
bioaccumulation
Ingestion &
Inhalation
Water
Ingestion
Humans
Ingestion
Inhalation
Figure C.4. On-site Unlined Burial
C-8
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters — Appendices
Natural Disaster
On-site Transportation
Mortalities
Diffusion from Compost
Windrows
Composting
Air
Sfomofd/
Uptake
Terrestrial \ floofuprtrte
Ingestion
Inhalation
Livestock
Leochmgfram
Compost Windrows
&
Application of Finished
Compost to Soil
Erosion S Runoff
Leaching Surface Water
Recharge
Incidental
Ingestion
Ingestion
Ingestion &
inhalation
Well
Water
Ingestion
t *-
Humans
Ingestion
Uptake,
bioaccumulation
Sedimentation,
Resuspension, &
Diffusive Exchange
Aquatic
Life
Sediment
Uptake,
bioaccumulation
Inhalation
Figure C.5. On-site Composting
C-9
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters — Appendices
Natural Disaster
Off-tile Transportation
Mortalities
Recovered Methane
Co-located Fuel
Use
CAA Permitted Release
Off-site Landfall
Fugitive Co ses
(C02, Methane)
Terrestrial
Plants
Recovered Leochale
Air
Sfoffloto^ Uptake
[ On-site Treatment I
1 System 1
CWM Permitted
Effluent Discharge
Off-site River
Inhalation
Livestock
Inhalation
J£
ingestion
Humans
Figure C.6. Off-site Landfilling
C-10
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters — Appendices
Natural Disaster
Mortalities
Off-site Traniportotion
CM Permitted Emissions
Air
Stomatal
Uptake
Terrestrial
Plants
Rendering
Unusable Solid Byproducts
Wastewater
On-site Treatment
System
Animal feed
CWA Permitted
Effluent Discharge
RCRA Subtitle 0
Landfill
Off-site River
Inhalation
Ingestion
Ingestion
Livestock
Ingestion
Humans
Inhalation
Figure C.7. Rendering
C-ll
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters — Appendices
Natural Disaster
Mortalities
fl
Particles on
-------
Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Natural Disaster
Mortalities
Particles and vapors
*
Air
Inhalation
Figure C.9. Carcass Handling
nri ^
Carcass
Handling
Ingestion;
Dermal
~
Humans
C-13
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters — Appendices
Natural Disaster
Mortalities
1
Particles and vapors
Transportation
.
Air
Stomatal
Uptake
Terrestrial
Plants
Routine Leakage,
Accidental Cargo
Spillage
Inhalation
Ingestion
Livestock
Ingestion
Ingestion
Incidental
Ingestion;
Dermal
Humans
Inhalation
Figure C.10. Carcass Transportation
044
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters — Appendices
C.3. Carcass Management Source Modules
Livestock Carcass Management Option
Figure
On-site Open Burning (pyre)
C.ll
On-site Air-curtain Burning
C.12
Off-site Fixed-facility Incineration
C.13
On-site Unlined Burial
C.14
On-site Composting
C.15
Off-site Lined Landfill
C.16
Rendering
C.ll
C-15
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters — Appendices
Combustion
Residual
Air ! Vapor Phase Chemicals
. (e g., CO,)
Water Vapor (H?0)
Smaller Particles (e.g., PM 2.5)
Larger Particles (e.g., PM 10)
Wet and dry
deposition
Wind
Wet deposition
Burial of ash in place
To Soil Module
Downwind to Soil and Surface Water Modules
Figure C.ll. Combustion-based Management: On-site Open Burning Module
C-16
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters — Appendices
Air Curtain
To Soil Module
Residual
Ash
Diesel Engine
Wind
Downwind
to Air
Module
Downwind to Soil and Surface Water Modules
Burial of ash in place
Larger Particles (e.g., PM 10)
Wef and dry
deposition
Wet deposition
Smaller Particles (e.g., PM 2.5)
Combustion
Vapor Phase Chemicals (e.g., CG?)
Water Vapor (Ht,0)
Figure C.12. Coinbustion-based Management: Air-curtain Burning Module
C-17
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters — Appendices
Downwind
to Air
Module
To Landfill Module
Air
Pollution
Control
Incinerator
Water Vapor (H20)
CAA
Permitted
Smaller Particles (e.g., PM 2.5}
Wind
Downwind to Soil and Surface Water Modules
Residual
Residual ash
Transport
Emissions
Wet and dry
deposition
Wef deposition
Vapor Phase Chemicals (e.g., C02)
Waste
water
NPDES
permitted
discharge to
surface water
Figure C.13. Combustion-based Management: Fixed-facility Incineration Module
C-18
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters — Appendices
Air
Methane, CO?, and other gases
Precipitation
Surface Soil
'infiltration
Buried Carcasses
Leaching
I
Air spaces
_Meth_ane
Advectlon: dissolved
chemicals
Leaching
Leaching
Subsurface Soil
Interstitial
Large
spaces
pores
V
y
Chemical & microbe
sorption/desorption
i
Advection: particles
with water
To Ground water (Aquifer) Module
Figure C.14. Land-based Management: On-site Burial Module
C-19
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters — Appendices
Air
Volatile
chemicals
. nh.: ;
'a
Water vapor
y!
CO,
Compost Covering (wood chips)
Decomposing Carcasses
aerobic decomposition generates heat, deactivates microbes)
Compost Underlayer (wood chips)
y Leaching
j Leaching
*
Leaching
Advection: dissolved
ichemicals
w
Chemical & microbe
sorption/desorption
f
\
Soil
Interstitial
Large
spaces
pores
>
¥
Advection: particles
with water
To Groundwater (Aquifer) Module
To Soil Module
On-site Use of
Finished Compost
Figure C.15. Land-based Management: Composting Module
C-20
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters — Appendices
Downwind to Air
Module
Co-located Facility
Permitted
air
releases
Methane
collection.
Air
C02, water vapor (H20)
Other vapor-phase
chemicals (e.g., methane)
A
- ->
Wind
- >
Water droplets
Fugitive off-
Precipitation
gassing
Landfi
Decomposing carcasses
f Leaching
mpermeable Liner
To Surface
Water Module
Leachate
collection
and
recycling
Wastewater
treatment plant
Figure C.16. Land-based Management: Off-site Landfill Module
Gas
recapture,
burning as
fuel
C-21
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters — Appendices
Rendering Facility
Air Pollution Control
To Air Module
raw material]
To non-
ruminant
animal feed
To Gffsite
Landfill
Module
S'Ze Heat w CaPture/
Reduction _ 9 condense
(crushing) "i Pr°CeSSmg t Steam
CO
V
Grinding & Mam Protein &
Screening Bones ^res:
T_
Meat and Bone Meal
(MBM) Storage
Fat
Cleanup
Wastewater
treatment plant
J
To Surface Water
Module
Fats to
manufacturing
uses of tallow,
etc. and for use
in animal feed
^Adapted from Meeker & Hamilton 2006 and from Bisplinghoff 2006
Figure C.17. Rendering Module"
C-22
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters — Appendices
C.3.1. Abiotic Compartment Modules
Livestock Carcass Management Option
Figure
Air
C.18
Soil
C.19
Surface Water arid Sediment
C.20
Groundwater
C.21
C-23
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters — Appendices
Release
during
burn
Long-
term
Releases
Air
Particulates
Dry
Deposition
Sorption
Vapor-phase (gases)
¦¦¦•>
Sorption
Water [e.g., rain droplets)
Wet
Deposition
S tomato I
uptake
Advection
r
To downwind
air;
concentration
decreasing with
increasing
distance from
source
L
J
(i.e., wind)
- ->
Inhalation / Humans,
Livestock, and
Wildlife
To surface soils, plant
surfaces, and surface water
bodies (sediments)
Plants
(a) Diffusive exchange of gases between air and surface soils
and between air and surface waters are not represented
here because net transfer of diffusive vapor-phase
chemical is relatively minor.
(b) Water as a phase in air (i.e., precipitation) is sporadic.
Figure C.18. Air Module3
C-24
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters — Appendices
Wet
Deposition
Wet & Dry
Water Deposition
Runoff
Diffusive
Exchanges
Water
Runoff
Particle
Erosion
Surface Soil Interstitial
Space
Pores
Leaching
Particle
Erosion
Subsurface Soil
Particles
Sorption/
Desorption
Leaching
Leaching
Water (i.e., precipitation)(>1
From
source or
from up-
gradient
surface
soils
To adjacent
surface
water
bodies or
more down-
gradient
surface soils
Air
Vapor-phase (gases)
To Groundwater (Aquifer) Module
(a) Precipitation is sporadic and can take different forms with different vapor (and particulate) scavenging efficiencies
Figure C.19. Soil Module11
C-25
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters — Appendices
Wet
Deposition
(i.e., precipitation
scavenging vapors)
Wet & dry
deposition
Diffusive Exchanges
Runoff
Water Column
Water (i.e., aqueous-phase) |
Erosion
Diffusive
Exchanges
Surface
Water
Recharge
Sedimentation
Particles
Pore
Water
Pore
Water
Water (i.e., precipitation)|a)
Sediment Pore Water
Suspended
Particles
Ground
water
Surface
Soils
Air
i Vapor-phase (gases)
Sediments
Sediment
Particles
Diffusive
Exchanges
(a) Precipitation is sporadic and can take differentforms with different vapor (and particulate) scavenging efficiencies
Figure C.20. Surface Water Module3
C-26
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters — Appendices
Surface Soils
Subsurface Soils
Interstitial
Spaces
Pores
Leaching
Groundwater (Aquifer)
Particles/Solids
I
Sorption/
desorption
Particles/
Solids
Leaching
Sorption/
desorption
Water (i.e., aqueous phase)
Pumping
/pulling
water
water
Water
Surface
water
recharge
To Surface Water Module
(aqueous phase)
Figure C.21. Groundwater (Aquifer) Module
C-27
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters — Appendices
C.3.2. Biotic Compartment Modules
Livestock Carcass Management Option
Figure
Aquatic Ecosystem
C.22
Terrestrial Plants
C.23
Livestock
C.24
Terrestrial Wildlife
C.24
Human Receptors
C.26
C-28
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters — Appendices
Organic Terrestrial Particles
Water Column
Algae
I
<" Zooplankton )
I
Minnows
Suspended
Particles
r~
Sediments
v-
Particles, Organic Particles
Capture by terrestrial animals
"Pan"
fish
(e.g.,
sunfish)
"Game" Fish
(e.g., pike, lake
trout, largemouth
bass)
i Capture yt
^frVI
N
t/
\
Diffusive uptake and *\
excretion of chemicals in
water across animal gills & ,
outer algal cell
Benthic
Invertebrates
Pore Water
Bottom
Fish
Compartment Legend:
Algae \ ) Invertebrates ( ("
Fish
Transfer Pathway
Legend:
I Sedimentation of
X dead organisms
Capture
Ingestion
Figure C.22. Aquatic Ecosystem Biotic Module
C-29
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters — Appendices
Humans
Wildlife
Livestock
Particulates
High Kow chemicals & microbes
sorbedto soil particles
Surface Soil
Subsurface
Soil
Root Uptake of Soluble Chemicals' J J/\, I
V
1
Crops
Water
Dry & Wet Deposition
Vapor-
phase Diffusive
(gases) Exchanges
Vapor-phase chemicals can be absorbed from air and lost H , . .
... , . , ... Irrigation ¦ Particle deposition I Ingestion
to air by plants when leaf stomata are open during the ^ v I
day.
Figure C.23. Terrestrial Plants Module
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters — Appendices
Poultry
Cattle
(grazers)
Ingestion
(feed)
Swine
Groundwat
er Module
Rendering
Module
Air Particulates
Inhalation
water
troughs
Ingestion
(drinking
Water)
Incidental
Soil
ingestion
ingestion
(forage
plants)
MBM
added
Ingestion (plant
materials)
Vapor-phase (|ases)
Terrestrial Plant
and Soils Modules
\
Figure C.24. Livestock Module
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters — Appendices
Air
Particulates
_ Y"?P0£~P h sse .[gases] _
Inhalation
Ingestion
(forage)
Terrestrial
Plants
Module
Herbivorous
Wildlife
Ingestion
(drinking
Water)
Piscivorous
Wildlife
Surface Water
Biotic Module
Bottom Fish
Capture and
ingestion by
piscivorous (fish-
eating) wildlife
"Pan" fish
(e.g.,
iunfish)
Figure C.25. Terrestrial Wildlife Module
C-32
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters — Appendices
Well Water
(Groundwater
Module)
Air 1 Particulates
J Vapor-phase (gases)
f N
Surface Water
Module
i <
Sediments
Home Water
Surface Soil
Module
Fish (Surface
Water Biotic
Module)
Ingestion i
Humans
Poultry
(Livestock
Module)
Ingestion
Inhalation
Incidental Ingestion (during
recreation/ swimming)
Incidental
Soil ingestion
Ingestion (drinking
water, cooking
water, e.g., in rice)
Dermal/Inhalation
(Bathing)
<•
Dairy
Ingestion
of Crop
Plants
Terrestrial
Plants
Module
Cattle
(Livestock
Module)
Ingestion of
Feed and
Forage
<
\
)
J
Figure C.26. Human Receptor Module
C-33
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
ViK* ^ nation
Section 4.1, Tables 4.1.1-4.1.3, of the main report present information for Iowa used in the
AERMOD modeling of chemical dispersion in air and dry and wet deposition rates from open-
pyre and air-curtain burning. This appendix presents additional details on how AERMOD works
and on chemical-specific information used in the model.
USEPA's AERMINUTE pre-processor (version 14337) processes sub-hourly wind data, which
are subsequently processed with the albedo, surface-roughness, and Bowen-ratio (used to
estimate latent heat flux) data using AERMET (version 14134). Some missing values for some
hours is typical across a year of data; with the 2014 Iowa City data, approximately 2% of hours
were missing values for critical parameters such that dispersion modeling would not be possible
for those hours.
After running AERMET, the missing values were populated with averages or typical values for
2014 at the station. Values averaged from a small number of surrounding hours were used for
missing values of wind speed and direction, temperature, and mixing height; when those
surrounding hours were all missing, values averaged from the closest non-missing hours were
used for wind speed and direction, and values averaged from the same time of day on
surrounding days were used for temperature and mixing height. The substituted values for wind
direction were not direct averages of other wind directions; rather, the wind vectors used in the
averaging calculation were first broken down into their scalar components, averaged, and then
the substitution vector was calculated. Wind speeds that were originally 0 m/s (causing
AERMOD to not estimate dispersion during those times) were replaced with 0.28 m/s, a default
value suggested in AERMOD's user's guide.
Station-average values (from 2014) for the same month and hour of day were used for missing
values of sensible heat flux, surface friction velocity, and convective velocity scale. A similar
method was used for missing values of Monin-Obukov length23, but the averaging was
conditional upon the sign of the sensible heat flux (conditionally-average negative values of
23 "The Monin-Obukhov length compares the ratio of turbulent kinetic energy produced by shear to that produced by
buoyancy." Clifton A et al. 2012. Turbine inflow characterization at the National Wind Technology Center. Presented at the
50th AIAA Aerospace Sciences Meeting, Nashville, TN.
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Monin-Obukov length when sensible heat flux was positive; and vice-versa). September was the
month with the greatest number of hours missing critical meteorology data (66 hr missing),
followed by April and January (about 30 hr missing for each).
This appendix includes three tables that describe the AERMOD modeling used in this
assessment. Table D. 1 summarizes data used to estimate particle deposition rates. Table D.2
summarizes constants used in the modeling. Table D.3 reviews air emission rate modeling
concerns.
Table D.l. To estimate particle deposition rates, AERMOD can use either of two different sets of
particle information. One set of inputs works for chemicals when the chemical is sorbed to
particles of a known size distribution. This set of deposition parameters is used for inorganic
chemicals released from coal burning in an open pyre.
The other set of inputs is used when the particle-size distribution is not known, but less than
about 10% of the chemical mass is sorbed to particles greater than 10 |im. In this case, there are
two parameter values required for each simulated chemical: (1) the fraction of the mass of total
particles with sorbed chemical and aerosol particles that are 2.5 |im or less in diameter (i.e.,
PM2.5) and (2) the mass-mean diameters (MMD). We modeled all organics (including the PAH)
using this set of deposition parameters. Ranges of particle MMDs and mass fractions are derived
from Table 4 of Bond et al. (2002). The modeled chemicals are bound to fly ash; therefore, we
identified the range of density values for fly ash from EPRI (2009; 65-100 lbs/ft3 = 1.04-1.76
g/cm3) and calculated the mean value (1.4 g/cm3) to use as particle density.
For PAHs released from carcasses in open pyres and from ACB pits, almost all naphthalene (i.e.,
99-100%) is released in vapor phase and remains in vapor phase after cooling, hence
naphthalene was modeled as 99-100% PM2.5, with a MMD of 0.1 |im. For PAHs of higher
molecular weights and more rings, the fraction sorbing to larger particles can increase and the
MMD increases to 0.2 or 0.3 |im depending on the chemical. For PAHs, Hays et al. (2003)
reported a mass mean diameter of 0.3 |im for wood (oak and Douglas fir) with low moisture
content (i.e., 13%) and 0.6 |im for the same woods with high moisture content (>24%). We also
assume particles are somewhat smaller when released from an air-curtain burner (ACB) unit,
D-2
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
because much of the fly ash is captured under the air curtain and is recirculated and reburned,
breaking up the larger particles.
For PAHs, heavy metals, and other chemicals, Lamberg et al. (2011) presented particle size
distributions for wood burning in different types of small-scale combustion units. Particles
ranged from 0.07-1.0 |im, with peaks around 0.1 to 0.3 in diameter. Particle sizes for wood
combustion reported by Kortelainen et al. (2015) peaked around 0.1-0.2 |im for wood chips
burned in a 40-kW combustor with a moving grate.
The 0.15-|im MMD for PAH compounds larger than naphthalene emitted to air from the open-
pyre burning of hay bales (or straw) are based on Zhang et al. (2011) measurements from
burning corn stover and wheat straw and assuming a relatively uniform particle size for burning
straw. For naphthalene, however, which would be released in vapor-phase, a diameter of 0.01
|im was assumed for aerosol particles to the extent they might be formed. Note that the fraction
of the chemical less than 2.5 |im in diameter includes vapors and condensation of vapors into or
onto very small particles, which could be inhaled by animals. Although data for PAH emissions
from other types of fuels indicated that up to 12% of the higher molecular weight PAHs might
sorb to particles larger than 2.5 |im, Zhang et al. (2011) data for crop straw residue burning
indicated that virtually all particles were smaller than 1 |im, and therefore less than 2.5 |im.
Given the difficulty in identifying particle size distributions associated with the different fuels,
different burn temperatures, and different chemicals, we ran AERMOD for PAHs in carcasses
with mean particle diameters of 0.1 and 1.0 |im. We found negligible effects on the pattern of
deposition with distance from the combustion unit. We conclude that air deposition estimates
were insensitive to the assigned mean particle size within that range.
Table D.2. Nearly all values for diffusivity and Henry's Law Constant, needed for AERMOD
modeling of vapor deposition, were available from EPA's Human Health Risk Assessment
Protocol (HHRAP) for Hazardous Waste Combustion Facilities (USEPA 2005). Values of
cuticular resistance, also required for vapor deposition, were available for some chemicals from
Wesely et al. (2002). Plant cuticular resistance (CR) indicates the potential for organic vapor-
phase chemicals to penetrate the external waxy cuticle of a leaf to the leaf interior at any time of
day. Cuticular resistance is proportional to a chemical's octanol-water partitioning coefficient
D-3
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
(Kow). That contrasts with water vapors and other volatile hydrophilic chemicals, which are
released only from the stomata (holes in the cuticle and leaf epidermis) on the undersurface of
leaves. The stomata also allow absorption of carbon dioxide from the air and release oxygen to
the air during daylight hours.
For values of CR for organic chemicals not available from Wesely et al. (2002), a value equal to
a chemical with a similar Kow and structure was assumed. For three PAHs, CR values are based
on other PAHs with the same number of rings (cyclopenta[c,d]pyrene=BaP; indeno[l,2,3-cd]-
pyrene and benzo[b]chrysene = dibenzo[a,h]anthracene). For eight dioxin/furans, we used CR
values for other 2,3,7,8-substituted congeners with the same number of chlorine atoms. No CR
values are available for metals; hence, we followed Wesely et al. (2002) and used the value of
107 s/m for the CR for all modeled metals. For diffusivity values not available from HHRAP
documentation (USEPA 2005), values are from Wesely et al. (2002) or estimated based on
molecular weight according to equations A3-2a and A3-2b in Volume 2, Appendix A, of
HHRAP (USEPA 2005).
For values of Henry's Law Constant (HLC) not available from HHRAP (USEPA 2005), we use
values for some chemicals found with the National Institutes of Health (e.g., ToxNet,
http://toxnet.nlm.nih.gov/) and the Royal Society of Chemistry (e.g., ChemSpider,
http://www.chemspider.com/). For metals, HHRAP recommends an HLC of zero if a measured
value was not available from the literature (i.e., assumes that metals are nonvolatile at ambient
temperatures and are insoluble in water). However, AERMOD cannot run if the HCL is set to
zero. We therefore set the HCL value for chromium, copper, iron, and manganese to the HCL
value of 2533 Pascal cubic meters per mole (Pa-m3/mol) in HHRAP for lead, nickel, and zinc.
Table D.3. To model air dispersion and deposition from land-based combustion methods,
AERMOD requires emission rates for vapor-phase and particle phase separately. The
measurements should be made post-dilution with ambient air and cooling to ambient air
temperatures, which induces condensation of some chemicals to aerosols and particles depending
on their boiling points. For chemicals in vapor phase at ambient temperatures, there would be
negligible net deposition to soils and surface waters around the source. For the emission rates
input to AERMOD in g/s listed in Table D.3, see the emission rate original data and calculations
D-4
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
as described in the main report and in other appendices. Appendix A describes the derivation of
PAH air emission factors (EFs in g/s) by congener for carcasses and each fuel type; Appendix B
provides the derivation of dioxin/furan EFs by fuel type.
D-5
-------
Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Table D.l. Parameterization of Emitted Particles.
Poll
Pyre Carcass
ACB Carcass
Pyre Coa
il
Pyre Hay
Pyre Wood
ACB Wood
Group
Pollutant
Frac
Diam
Frac
Diam
Diam
Mass
Dens
Frac
Diam
Frac
Diam
Frac
Diam
Frac
Diam
PM25
(jim)
PM25
(Jim)
(Jim)
Frac
(g/cm3)
PM25
(Jim)
PM25
(Jim)
PM25
(Jim)
PM25
(Jim)
PAH
Naph-
thalene
0.99
0.1
0.99
0.1
NM
NM
NM
NM
NM
1
0.01
NM
NM
0.99
0.1
PAH
Acenaph-
thylene
0.95
0.2
0.95
0.2
NA
NA
NA
0.95
0.2
1
0.15
0.99
0.3
0.95
0.2
PAH
Phenan-
threne
0.95
0.2
0.95
0.2
NA
NA
NA
0.95
0.2
0.99
0.15
0.99
0.3
0.95
0.2
PAH
Fluorene
0.95
0.2
0.95
0.2
NA
NA
NA
0.95
0.2
0.99
0.15
0.99
0.3
0.95
0.2
PAH
Acenaph-
thene
0.95
0.2
0.95
0.2
NA
NA
NA
0.95
0.2
0.99
0.15
0.99
0.3
NM
NM
PAH
Anthracene
0.95
0.2
0.95
0.2
NA
NA
NA
0.95
0.2
0.99
0.15
0.99
0.3
0.95
0.2
PAH
Pyrene
0.93
0.3
0.93
0.3
NA
NA
NA
0.93
0.3
0.99
0.15
0.99
0.3
0.93
0.3
PAH
Chrysene
0.93
0.3
0.93
0.3
NA
NA
NA
0.93
0.3
0.99
0.15
0.99
0.3
0.93
0.3
PAH
Fluoran-
thene
0.93
0.3
0.93
0.3
NA
NA
NA
0.93
0.3
0.99
0.15
0.99
0.3
0.93
0.3
PAH
Benzo[a]-
antliracene
0.93
0.3
0.93
0.3
NA
NA
NA
0.93
0.3
0.99
0.15
0.99
0.3
0.93
0.3
PAH
Benzo[a]-
pyrene
0.9
0.3
0.90
0.3
NA
NA
NA
0.90
0.3
0.99
0.15
0.99
0.3
0.90
0.3
PAH
Benzo[e]-
pyrene
0.9
0.3
0.90
0.3
NA
NA
NA
0.90
0.3
0.99
0.15
0.99
0.3
0.90
0.3
PAH
Benzo[b]-
fluoran-
thene
0.9
0.3
0.90
0.3
NA
NA
NA
0.90
0.3
0.99
0.15
0.99
0.3
0.90
0.3
PAH
Benzo[k]-
fluoran-
thene
0.9
0.3
0.90
0.3
NA
NA
NA
0.90
0.3
0.99
0.15
0.99
0.3
0.90
0.3
PAH
Cyclo-
penta[c,d]-
pyrene
0.9
0.3
0.90
0.3
NM
NM
NM
NM
NM
NM
NM
NM
NM
NM
NM
PAH
Perylene
0.9
0.3
0.90
0.3
NM
NM
NM
NM
NM
0.99
0.15
0.99
0.3
0.90
0.3
PAH
Dibenz[a,h]
antliracene
0.88
0.2
0.88
0.2
NA
NA
NA
0.88
0.4
0.99
0.15
0.99
0.3
0.88
0.3
D-6
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Poll.
Group
Pollutant
Pyre Carcass
Frac Diam
PM2.5 (|im)
ACB Carcass
Frac Diam
PM2.5 (|im)
Diam
(Jim)
Mass
Frac
Pyre Coa
Dens
(g/cm3)
il
Frac
PM25
Diam
(Jim)
Pyre Hay
Frac Diam
PM2.5 (|im)
Pyre Wood
Frac Diam
PM2.5 (|im)
ACB Wood
Frac Diam
PM2.5 (|im)
PAH
Indeno-
[l,2,3-c,d]-
pyrene
0.88
0.2
0.88
0.2
NA
NA
NA
0.88
0.4
0.99
0.15
0.99
0.3
0.88
0.3
PAH
Benzo[g,h,i
]-perylene
0.88
0.2
0.88
0.2
NA
NA
NA
0.88
0.4
0.99
0.15
0.99
0.3
0.88
0.3
PAH
Benzo[b]-
chrysene
0.88
0.2
0.88
0.2
NM
NM
NM
NM
NM
NM
NM
0.99
0.3
NM
NM
PAH
Coronene
0.88
0.2
0.88
0.2
NA
NA
NA
0.88
0.4
NM
NM
0.99
0.3
0.88
0.3
Dioxin
HeptaCDD,
1,2,3,4,6,7,
8
NM
NM
NM
NM
NM
NM
NM
NM
NM
NM
NM
0.99
0.2
0.99
0.2
Dioxin
HeptaCDF,
1,2,3,4,6,7,
8
NM
NM
NM
NM
NM
NM
NM
NM
NM
NM
NM
0.99
0.2
0.99
0.2
Dioxin
HeptaCDF,
1,2,3,4,7,8,
9
NM
NM
NM
NM
NM
NM
NM
NM
NM
NM
NM
0.99
0.2
0.99
0.2
Dioxin
HexaCDD,
1,2,3,4,7,8-
NM
NM
NM
NM
NM
NM
NM
NM
NM
NM
NM
0.99
0.2
0.99
0.2
Dioxin
HexaCDD,
1,2,3,6,7,8-
NM
NM
NM
NM
NM
NM
NM
NM
NM
NM
NM
0.99
0.2
0.99
0.2
Dioxin
HexaCDD,
1,2,3,7,8,9 -
NM
NM
NM
NM
NM
NM
NM
NM
NM
NM
NM
0.99
0.2
0.99
0.2
Dioxin
HexaCDF,
1,2,3,4,7,8-
NM
NM
NM
NM
NM
NM
NM
NM
NM
NM
NM
0.99
0.2
0.99
0.2
Dioxin
HexaCDF,
1,2,3,6,7,8-
NM
NM
NM
NM
NM
NM
NM
NM
NM
NM
NM
0.99
0.2
0.99
0.2
Dioxin
HexaCDF,
1,2,3,7,8,9-
NM
NM
NM
NM
NM
NM
NM
NM
NM
NM
NM
0.99
0.2
0.99
0.2
Dioxin
HexaCDF,
2,3,4,6,7,8-
NM
NM
NM
NM
NM
NM
NM
NM
NM
NM
NM
0.99
0.2
0.99
0.2
Dioxin
OctaCDD,
1,2,3,4,6,7,
8,9-
NM
NM
NM
NM
NM
NM
NM
'
NM
NM
NM
NM
0.99
0.2
0.99
0.1
D-7
-------
Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Poll
Pyre Carcass
ACB Carcass
Pyre Coa
il Pyre Hay
Pyre Wood
ACB Wood
Group
Pollutant
Frac
PM25
Diam
(jim)
Frac
PM2.5
Diam
(Jim)
Diam
(Jim)
Mass
Frac
Dens
(g/cm3)
Frac
PM25
Diam
(Jim)
Frac
PM25
Diam
(Jim)
Frac
PM25
Diam
(Jim)
Frac
PM25
Diam
(Jim)
Dioxin
OctaCDF,
1,2,3,4,6,7,
8,9-
NM
NM
NM
NM
NM
NM
NM
NM
NM
NM
NM
0.99
0.2
0.99
0.2
Dioxin
PentaCDD,
1,2,3,7,8-
NM
NM
NM
NM
NM
NM
NM
NM
NM
NM
NM
0.99
0.2
0.99
0.2
Dioxin
PentaCDF,
1,2,3,7,8-
NM
NM
NM
NM
NM
NM
NM
NM
NM
NM
NM
0.99
0.2
0.99
0.2
Dioxin
PentaCDF,
2,3,4,7,8-
NM
NM
NM
NM
NM
NM
NM
NM
NM
NM
NM
0.99
0.2
0.99
0.2
Dioxin
TetraCDD,
2,3,7,8-
NM
NM
NM
NM
NM
NM
NM
NM
NM
0.99
0.15
0.99
0.2
0.99
0.2
Dioxin
TetraCDF,
2,3,7,8-
NM
NM
NM
NM
NM
NM
NM
NM
NM
NM
NM
0.99
0.2
0.99
0.2
Metal
Arsenic
NM
NM
NM
NM
NM
NM
NM
NM
NM
NM
NM
0.99
0.3
0.99
0.2
Metal
Cadmium
0.7
0.6
0.99
0.2
NM
NM
NM
NM
NM
NM
NM
0.99
0.3
0.99
0.2
Metal
Cliromium
0.55
1.2
0.99
0.2
0.1
0.375
0.75
1.75
6.25
25
0.54
0.27
0.07
0.08
0.02
0.02
1.4
1.4
1.4
1.4
1.4
1.4
NA
NA
NM
NM
0.99
0.3
0.99
0.2
Metal
Copper
0.7
1.0
0.99
0.2
0.1
0.375
0.75
1.75
6.25
25
0.54
0.27
0.07
0.08
0.02
0.02
1.4
1.4
1.4
1.4
1.4
1.4
NA
NA
NM
NM
0.99
0.3
0.99
0.2
Metal
Iron
0.7
1.0
0.99
0.2
0.1
0.375
0.75
1.75
6.25
25
0.54
0.27
0.07
0.08
0.02
0.02
1.4
1.4
1.4
1.4
1.4
1.4
NA
NA
NM
NM
0.99
0.3
0.99
0.2
D-8
-------
Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Poll
Pyre Carcass
ACB Carcass
Pyre Coa
il Pyre Hay
Pyre Wood
ACB Wood
Group
Pollutant
Frac
PM25
Diam
(jim)
Frac
PM25
Diam
(Jim)
Diam
(Jim)
Mass
Frac
Dens
(g/cm3)
Frac
PM25
Diam
(Jim)
Frac
PM25
Diam
(Jim)
Frac
PM25
Diam
(Jim)
Frac
PM25
Diam
(Jim)
Metal
Lead
0.75
0.5
0.99
0.2
0.1
0.375
0.75
1.75
6.25
25
0.54
0.27
0.07
0.08
0.02
0.02
1.4
1.4
1.4
1.4
1.4
1.4
NA
NA
NM
NM
0.99
0.3
0.99
0.2
Metal
Manganese
0.45
1.8
0.99
0.2
0.1
0.375
0.75
1.75
6.25
25
0.54
0.27
0.07
0.08
0.02
0.02
1.4
1.4
1.4
1.4
1.4
1.4
NA
NA
NM
NM
0.99
0.3
0.99
0.2
Metal
Nickel
0.6
1.0
0.99
0.2
0.1
0.375
0.75
1.75
6.25
25
0.54
0.27
0.07
0.08
0.02
0.02
1.4
1.4
1.4
1.4
1.4
1.4
NA
NA
NM
NM
0.99
0.3
0.99
0.2
Metal
Zinc
0.8
0.4
0.99
0.2
0.1
0.375
0.75
1.75
6.25
25
0.54
0.27
0.07
0.08
0.02
0.02
1.4
1.4
1.4
1.4
1.4
1.4
NA
NA
NM
NM
0.99
0.3
0.99
0.2
Abbreviations: Dens = particle densities (g/cm3) corresponding to the particulate diameter classes in the "Diam" column; Diam = mass-mean particulate diameter (|im); Frac PM2.5
= mass fraction of particles 2.5 (im in diameter or less; Mass Frac = particle mass fractions corresponding to the particulate diameter classes in the "Diam" column; NA = this
particulate size scheme not used; NM = this pollutant not modeled for this combusted material from this management option; PAH = polyaromatic hydrocarbon; ACB = air-curtain
burner
Note: Pyre-Wood includes kindling. Pyre-Hay is for hay bales or straw.
D-9
-------
Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Table D.2. Parameterization of Emitted Vapor-phase Pollutants.
Pollutant
Group
Pollutant
Diffusivity in Air
(cm2/s)
Diffusivity in
Water (cm2/s)
Cuticular Resistance to Uptake by
Lipids for Individual Leaves (s/cm)
Henry's Law
Constant (Pa
m3/mol)
PAH
Naphthalene
5.90E-02
7.50E-06
3.65E+02
4.86E+01
PAH
Acenaphthylene
6.65E-02
7.07E-01
3.59E+01
1.27E+01
PAH
Phenanthrene
1.00E-03
1.00E-05
2.33E+01
2.33E+00
PAH
Fluorene
1.00E-03
1.00E-05
9.56E+01
6.48E+00
PAH
Acenaphthene
1.00E-03
1.00E-05
1.17E+02
1.62E+01
PAH
Anthracene
1.00E-03
1.00E-05
3.10E+01
6.59E+00
PAH
Pyrene
1.00E-03
1.00E-05
3.88E+00
1.11E+00
PAH
Chrysene
1.00E-03
1.00E-05
4.43E-01
9.63E+00
PAH
Fluoranthene
1.00E-03
1.00E-05
5.01E+00
1.62E+00
PAH
Benzo [a] anthracene
5.10E-02
9.00E-06
3.55E+00
3.45E-01
PAH
Benzo[a]pyrene
4.30E-02
9.00E-06
4.41E-01
1.11E-01
PAH
Benzo [e]pyrene
5.13E-02
4.44E-01
8.55E-02
2.00E-02
PAH
Benzo [b]fluoranthene
1.00E-03
1.00E-05
1.33E+02
1.12E+01
PAH
Benzo [kjfluoranthene
1.00E-03
1.00E-05
1.95E-01
8.41E-02
PAH
Cyclopenta[c,d]pyrene
5.12E-02
5.92E-06
4.41E-01
4.12E-01
PAH
Perylene
5.13E-02
4.44E-01
1.86E-02
3.04E+02
PAH
Dibenz[a,h]anthracene
1.00E-03
1.00E-05
2.09E-03
1.52E-03
PAH
Indeno [1,2,3 -c,d]pyrene
1.00E-03
1.00E-05
2.09E-03
1.62E-01
PAH
Benzo [g,hi]perylene
5.05E-02
4.16E-01
5.62E-01
2.78E-02
PAH
Benzo [b] chrysene
4.46E-02
5.16E-06
2.09E-03
4.95E-02
PAH
Coronene
4.85E-02
3.89E-01
3.82E-03
4.35E+01
Dioxin
HeptaCDD, 1,2,3,4,6,7,8-
9.05E-02
8.00E-06
5.97E-01
1.22E+00
Dioxin
HeptaCDF, 1,2,3,4,6,7,8-
2.03E-02
8.00E-06
1.27E+01
1.43E+00
Dioxin
HeptaCDF, 1,2,3,4,7,8,9-
2.03E-02
8.00E-06
1.27E+01
1.42E+00
Dioxin
HexaCDD, 1,2,3,4,7,8-
9.44E-02
8.00E-06
1.20E+00
1.08E+00
Dioxin
HexaCDD, 1,2,3,6,7,8-
9.44E-02
8.00E-06
1.20E+00
1.11E+00
Dioxin
HexaCDD, 1,2,3,7,8,9 -
9.44E-02
8.00E-06
1.20E+00
1.11E+00
D-10
-------
Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Table D.2. Parameterization of Emitted Vapor-phase Pollutants.
Pollutant
Group
Pollutant
Diffusivity in Air
(cm2/s)
Diffusivity in
Water (cm2/s)
Cuticular Resistance to Uptake by
Lipids for Individual Leaves (s/cm)
Henry's Law
Constant (Pa
m3/mol)
Dioxin
HexaCDF, 1,2,3,4,7,8-
2.12E-02
8.00E-06
1.11E+01
1.45E+00
Dioxin
HexaCDF, 1,2,3,6,7,8-
2.12E-02
8.00E-06
1.11E+01
7.41E-01
Dioxin
HexaCDF, 1,2,3,7,8,9-
2.12E-02
8.00E-06
1.11E+01
1.11E+00
Dioxin
HexaCDF, 2,3,4,6,7,8-
2.12E-02
8.00E-06
1.11E+01
1.11E+00
Dioxin
OctaCDD, 1,2,3,4,6,7,8,9-
8.69E-02
8.00E-06
4.94E+00
6.84E-01
Dioxin
OctaCDF, 1,2,3,4,6,7,8,9-
1.95E-02
8.00E-06
1.42E+00
1.90E-01
Dioxin
PentaCDD, 1,2,3,7,8-
9.88E-02
8.00E-06
5.47E-01
2.63E-01
Dioxin
PentaCDF, 1,2,3,7,8-
2.23E-02
8.00E-06
3.99E+00
5.07E-01
Dioxin
PentaCDF, 2,3,4,7,8-
2.23E-02
8.00E-06
3.99E+00
5.05E-01
Dioxin
TetraCDD, 2,3,7,8-
1.04E-01
5.60E-06
7.84E+00
3.33E+00
Dioxin
TetraCDF, 2,3,7,8-
2.35E-02
6.01E-06
9.67E+00
1.46E+00
Abbreviations: mol = moles; s = seconds.
D-ll
-------
Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Table D.3. Modeled Emission Rates (g/s) for Vapor-phase and Particle-phase Pollutants.
Pollutant
Pyre Carcass
ACB Carcass
Pyre Coal
Pyre Hay Bales
Pyre
Wood/Kindling
ACB Wood
V
P
V
P
V
P
V
P
Va
P
Va
Total
PAHs
Naph-
thalene
3.49E-
02
9.90E-04
4.46E-04
4.60E-05
NM
NM
2.49E-03
2.51E-5
NM
NM
0
5.61E-05
Acenaph-
thylene
3.42E-
03
4.28E-05
6.33E-05
1.44E-06
1.96E-
08
7.87E-11
1.17E-04
1.08E-5
0
1.21E-06
0
2.28E-05
Phenan-
threne
4.31E-
03
2.17E-03
7.19E-05
2.88E-06
2.15E-
06
1.68E-09
9.25E-05
1.21E-4
0
5.52E-05
0
1.63E-05
Fluorene
2.05E-
03
1.13E-04
1.58E-05
2.88E-06
1.21E-
07
1.81E-09
1.92E-05
1.12E-5
0
2.90E-06
0
1.87E-07
Acenaph-
thene
7.98E-
04
9.69E-05
5.75E-06
2.88E-06
1.40E-
08
ND
4.77E-05
4.30E-5
0
4.11E-08
NM
NM
Anthracene
1.06E-
03
5.45E-04
1.44E-06
7.19E-07
5.33E-
08
5.25E-11
1.72E-05
2.21E-5
0
1.98E-06
0
1.54E-06
Pyrene
1.52E-
03
7.35E-03
1.44E-05
2.88E-06
1.14E-
07
1.97E-09
1.04E-05
5.19E-5
0
8.66E-06
0
1.14E-05
Clirysene
1.95E-
04
3.85E-04
5.75E-06
1.44E-06
3.78E-
08
1.83E-08
6.89E-06
2.12E-5
0
1.80E-05
0
8.13E-07
Fluoran-
thene
1.51E-
03
5.84E-03
1.58E-05
2.88E-06
2.16E-
07
1.05E-10
1.11E-05
5.38E-5
0
9.25E-06
0
9.76E-06
Benzo[a]-
antliracene
1.93E-
04
4.92E-04
2.16E-06
4.31E-07
3.78E-
09
1.92E-09
6.63E-06
1.74E-5
0
1.93E-05
0
6.67E-07
Benzo[a]-
pyrene
2.30E-
04
1.05E-04
1.44E-06
7.19E-07
ND
4.49E-09
2.69E-05
6.72E-5
0
3.02E-05
0
1.22E-06
Benzo[e]-
pyrene
3.40E-
04
4.52E-04
2.16E-06
7.19E-07
3.81E-
09
4.49E-08
ND
1.13E-4
0
1.90E-05
0
4.92E-07
Benzo[b]-
fluoran-
thene
1.88E-
04
2.15E-04
2.88E-06
7.19E-07
4.67E-
09
2.68E-08
ND
7.25E-5
0
1.68E-05
0
9.76E-07
Benzo[k]-
fluoran-
thene
1.88E-
04
2.15E-04
2.88E-06
7.19E-07
4.67E-
09
2.68E-08
7.95E-06
2.70E-5
0
1.68E-05
0
7.81E-07
Cyclo-
penta[c,d]-
pyrene
5.54E-
05
7.30E-05
5.03E-06
1.44E-07
NM
NM
NA
NA
NM
NM
NM
NM
D-12
-------
Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Pollutant
Pyre Carcass
ACB Carcass
Pyre Coal
Pyre Hay Bales
Pyre
Wood/Kindling
ACB Wood
V
P
V
P
V
P
V
P
Va
P
Va
Total
Perylene
1.06E-
04
7.43E-05
4.31E-06
1.44E-06
NM
NM
ND
2.40E-5
0
4.39E-06
0
1.71E-06
Dibenz[a,h]
anthracene
3.71E-
04
2.48E-04
1.44E-06
7.19E-07
ND
1.55E-08
ND
1.01E-5
0
1.51E-06
0
8.94E-07
Indeno-
[l,2,3-c,d]-
pyrene
1.27E-
03
1.02E-03
2.88E-06
7.19E-07
ND
2.18E-08
ND
9.54E-5
0
1.65E-05
0
2.60E-06
Benzo[g,h,i]
-perylene
3.70E-
04
4.37E-04
2.88E-06
1.44E-06
ND
2.88E-08
8.83E-06
1.01E-5
0
8.44E-06
0
6.75E-08
Benzo[b]-
clirysene
2.24E-
04
9.69E-05
5.75E-06
1.44E-06
NM
NM
NA
NM
0
1.05E-06
NM
NM
Coronene
3.51E-
04
2.17E-04
4.31E-06
1.44E-06
ND
2.94E-08
NA
NM
0
3.73E-06
0
1.64E-06
Dioxins
HeptaCDD,
1,2,3,4,6,7,8
NM
NM
NM
NM
NM
NM
NM
NM
2.27E-12
1.19E-11
1.49E-10
7.83E-10
HeptaCDF,
1,2,3,4,6,7,8
NM
NM
NM
NM
NM
NM
NM
NM
4.82E-13
2.53E-12
2.12E-10
1.11E-09
HeptaCDF,
1,2,3,4,7,8,9
NM
NM
NM
NM
NM
NM
NM
NM
9.93E-14
5.21E-13
2.27E-11
1.19E-10
HexaCDD,
1,2,3,4,7,8-
NM
NM
NM
NM
NM
NM
NM
NM
6.12E-13
1.04E-12
7.12E-11
1.21E-10
HexaCDD,
1,2,3,6,7,8-
NM
NM
NM
NM
NM
NM
NM
NM
7.00E-13
1.19E-12
8.52E-11
1.45E-10
HexaCDD,
1,2,3,7,8,9 -
NM
NM
NM
NM
NM
NM
NM
NM
8.75E-13
1.49E-12
1.98E-10
3.37E-10
HexaCDF,
1,2,3,4,7,8-
NM
NM
NM
NM
NM
NM
NM
NM
5.17E-13
7.45E-13
2.74E-10
3.94E-10
HexaCDF,
1,2,3,6,7,8-
NM
NM
NM
NM
NM
NM
NM
NM
2.38E-13
3.43E-13
3.05E-10
4.39E-10
HexaCDF,
1,2,3,7,8,9-
NM
NM
NM
NM
NM
NM
NM
NM
4.66E-13
6.70E-13
1.30E-10
1.87E-10
D-13
-------
Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Pollutant
Pyre Carcass
ACB Carcass
Pyre Coal
Pyre Hay Bales
Pyre
Wood/Kindling
ACB Wood
V
p
V
p
V
p
V
P
Va
p
Va
Total
HexaCDF,
2,3,4,6,7,8-
NM
NM
NM
NM
NM
NM
NM
NM
7.24E-13
1.04E-12
1.40E-10
2.02E-10
OctaCDD,
1,2,3,4,6,7,8
,9-
NM
NM
NM
NM
NM
NM
NM
NM
1.49E-12
2.83E-11
1.84E-10
3.50E-09
OctaCDF,
1,2,3,4,6,7,8
,9-
NM
NM
NM
NM
NM
NM
NM
NM
3.41E-13
8.19E-12
2.95E-11
7.08E-10
PentaCDD,
1,2,3,7,8-
NM
NM
NM
NM
NM
NM
NM
NM
2.82E-12
1.04E-12
2.24E-10
8.29E-11
PentaCDF,
1,2,3,7,8-
NM
NM
NM
NM
NM
NM
NM
NM
3.48E-12
1.64E-12
9.07E-10
4.27E-10
PentaCDF,
2,3,4,7,8-
NM
NM
NM
NM
NM
NM
NM
NM
3.80E-12
1.79E-12
8.68E-10
4.08E-10
TetraCDD,
2,3,7,8-
NM
NM
NM
NM
NM
NM
ND
1.7E-11
4.30E-12
8.19E-13
2.19E-10
4.17E-11
TetraCDF,
2,3,7,8-
NM
NM
NM
NM
NM
NM
NM
NM
3.77E-12
1.19E-12
2.27E-09
7.18E-10
Metals (b)
Arsenic
0
0
0
0
0
1.04E-05
NM
NM
0
1.09E-05
0
1.04E-05
Cadmium
0
3.04E-05
0
6.73E-06
NM
NM
NM
NM
0
8.11E-06
0
6.30E-05
Chromium
0
2.30E-04
0
6.90E-05
0
1.08E-04
NM
NM
0
3.62E-06
0
2.61E-04
Copper
0
1.15E-04
0
3.26E-05
0
1.34E-04
NM
NM
0
1.34E-05
0
3.34E-04
Iron
0
7.23E-03
0
1.84E-03
0
7.72E-02
NM
NM
0
2.87E-04
0
1.83E-02
Lead
0
2.75E-04
0
1.12E-04
0
5.01E-05
NM
NM
0
3.06E-05
0
2.15E-04
Manganese
0
8.49E-05
0
2.71E-05
0
6.47E-04
NM
NM
0
7.31E-05
0
2.48E-02
Nickel
0
2.86E-04
0
8.00E-05
0
4.77E-06
NM
NM
0
4.35E-06
0
7.07E-05
Zinc
0
2.78E-04
0
1.17E-04
0
1.56E-04
NM
NM
0
2.29E-03
0
5.95E-03
Abbreviations: 0 = assumed to be zero; ACB = air-curtain burning; NA = not among analytes - not selected for measurement; ND = not detected; NM = not modeled; P =
particulate phase; s = seconds; V = vapor phase; CDD = chlorinated dibenzodioxins; CDF = chlorinated dibenzofurans.
a For PAHs from wood combustion, only particles sampled and analyzed for PAH content; however, samples obtained post condensation (Hays et al. 2003). Presumably vapor-
phase PAHs did not deposit near the open pyre or ACB unit.
b It was assumed that inorganic metals all would condense upon mixing with cooler ambient air and therefore all would be found in particulate phase outside the rising plume from
the fire. Hie vapor-phase metal emissions therefore are all set equal to zero.
D-14
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Volume II, Appendices
D.l. References
Bond TC, Covert DS, Kramlich JC, Larson TV, Charlson RJ (2002). Primary particle emissions
from residential coal burning: Optical properties and size distributions. Journal of Geophysical
Research. 107(D21):ICC 9-1-ICC 9-14.
EPRI (2009). Coal ash: characteristics, management and environmental issues. Technical Update
- Coal Combustion Products - Environmental Issues. Palo Alto, CA: Electric Power Research
Institute. September 2009.
Hays MD, Smith ND, Kinsey J, et al. (2003). Polycyclic aromatic hydrocarbon size distributions
in aerosols from appliances of residential wood combustion as determined by direct thermal
desorption-GC/MS. J Aerosol Science 34: 1061-1084.
Kortelainen M, Jokiniemi J, Nuutinen I, et al. (2015). Ash behaviour and emission formation in a
small-scale reciprocating-grate combustion reactor operated with wood chips, reed canary grass,
and barley straw. Fuel 143: 80-88.
Lamberg H, Nuutinen K, Tissari J, et al. (2011). Physicochemical characterization of fine
particles from small-scale wood combustion. Atmospheric Environment 45: 7635-7643.
USEPA (U.S. Environmental Protection Agency) (2005). Human Health Risk Assessment
Protocol for Hazardous Waste Combustion Facilities. Washington, DC: U.S. Environmental
Protection Agency, Office of Solid Waste and Emergency Response, Report no. EPA530-R-05-
006.
Wesely M, Doskey PV, Shannon JD (2002). Deposition Parameterizations for the Industrial
Source Complex (ISC3) Model. Argonne National Laboratory. June 2002. ANL/ER/TR-01/003.
Zhang H, Hu D, Chen J, et al. (2011). Particle size distribution and polycyclic aromatic
hydrocarbons emissions from agricultural crop residue burning. Environmental Science and
Technology 45: 5477-5482.
D-15
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
v y Description of the HHRAP Soil and Surface Water
(SSW} Screening Mode!
E.l. Introduction
This appendix provides further information on the model used in the exposure assessment for
livestock carcass management options to estimate the fate and transport of chemicals in the soil,
surface water, and sediment compartments of the hypothetical farm site. The model is based
primarily on methods provided by the USEPA's Human Health Risk Assessment Protocol
(HHRAP) for Hazardous Waste Combustion Facilities (USEPA 2005) for hazardous waste
combustion units (USEPA 2005). For this reason, the model is titled the HHRAP Soil and
Surface Water Screening Model (hereafter referred to as the SSW Screening Model or SSW).
The fate and transport of chemicals through the modeled environment is estimated in the SSW
Screening Model using a set of algorithms to predict long-term, steady-state concentrations in
environmental media from continuous sources. Conceptually, the modeled environment, a
hypothetical water body and the surrounding watershed, is evaluated with respect to the chemical
loads and losses to each of three "compartments" or categories of environmental media: (1) air,
(2) watershed soil, and (3) the water body of interest (inclusive of both the water column and the
underlying benthic sediment). Within each of those three media types, equilibrium between
chemical and environmental phases is assumed (e.g., between dissolved and sorbed fractions of
chemical present in surface soil, in pore water, and sorbed to soil particles). Note that for the
water body, the assumption of equilibrium conditions drives partitioning between the water
column, including both freely dissolved chemical and chemical sorbed to suspended sediments,
and the benthic sediments, including both dissolved chemical in sediment pore water and
chemical sorbed to benthic sediment particles.
The algorithms also assume steady-state conditions within each compartment given the total
mass of chemical added to the system as a whole. Loading and loss processes from the
compartments are assumed to occur via deposition, diffusion, erosion, runoff, leaching,
volatilization, and sediment burial processes. Chemical partitioning between phases within a
compartment is calculated assuming equilibrium conditions. As in the HHRAP equations, the
algorithms in the SSW Screening Model do not maintain a chemical mass balance, and no
E-l
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
chemical feedback mechanisms are included. For example, the volatilization of chemical from a
lake of 10 to 10,000s of acres does not significantly affect the concentration of chemical in air.
E.2, Use of HHRAP Framework
USEPA developed HHRAP to facilitate multi-pathway, site-specific risk assessments for
facilities burning hazardous waste. However, the algorithms in HHRAP can be applied for air
sources other than combustors. HHRAP is available from USEPA as document and companion
parameters database.24 The HHRAP document is intended to provide a transparent,
comprehensive, defensible, and scientifically-supported approach and algorithms that risk
assessors can use to inform decision-making for permitting a hazardous waste combustion
facility. The HHRAP protocol is a "model" in the broader sense (i.e., a conceptual approach for
estimating fate and transport, exposure, and risk) rather than a computational tool that can be
operated by a user to provide numerical results (such as a computer program). The protocol
document contains recommended procedures for estimating chemical concentrations in
environmental media, associated human exposures, and the resulting risks for exposed
individuals.
We based the Excel™-based SSW Screening Model on the HHRAP algorithms to estimate soil,
surface water, and sediment concentrations. Algorithms from HHRAP are peer reviewed, and the
documentation is familiar to risk assessors. As compiled by USEPA, HHRAP default values for
parameters provide a valuable starting point for configuring the datasets included in the SSW.
For those reasons, the SSW is expected to be robust while flexibly allowing interpretation of the
data available for input.
Where possible, the parameter names, symbols, and equations included in the SSW Screening
Model are consistent with the information presented in USEPA's HHRAP documentation. In this
appendix, cross-references to HHRAP equations are provided where relevant. One important
difference between the expressions presented in HHRAP and equations used the SSW is the
incorporation of the chemical source term. For this project, AERMOD is used to estimate total
chemical deposited from air to soils over 48 hours for combustion-based management options,
24 EPA's HHRAP document and companion parameters database is available for download from:
http://www3 .epa. gov/epawaste/hazard/tsd/td/combust/risk.htm.
E-2
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
not the equations in HHRAP. The AERMOD deposition rates are input to the SSW Screening
Model, which then estimates the soil concentrations soon after the burns and the soil
concentrations once again for one year later (after losses via microbial and abiotic degradation
processes and chemical losses from erosion and runoff). The SSW also is used to estimate
chemical transport from soils to surface water (the lake) via runoff and erosion. The SSW
equations that simulate chemical runoff and erosion are based on the same conceptual
relationships as those included in the HHRAP expressions. Finally, concentrations of chemicals
in the top 20 cm of surface soils following amendment with finished compost are calculated off-
line. From those, the SSW Screening Model estimates losses from microbial and abiotic
degradation and losses via erosion and runoff over one year, and reports the quantities remaining
at one year. Inputs for the SSW Screening Model for combustion-based carcass management
options differ from those for compost-amended soils (part of the composting option). For both of
the on-site combustion options, AERMOD results (total deposition from air over a 48-hr burn)
are input to the SSW. AERMOD predicts location-specific deposition rates in a grid of cells 250
x 250 meters distributed across a 500-acre (202-hectare) watershed. The maximum total
deposition rate for each chemical predicted by AERMOD is input to SSW. That is equivalent to
using the location of maximum deposition to represent the entire watershed.
For burial, there is no runoff or erosion, only leaching of chemical from the buried carcasses
toward groundwater. For composting, there is a very small amount of leaching from the compost
windrow to groundwater and limited erosion and runoff that carry chemicals to the lake (e.g.,
Table 5.3.10 in the report). We assume that a compost windrow decomposes over one year. The
finished compost is tilled into 10 acres of land one edge of which is adjacent to the lake. (We
could not adapt the HHRAP equations to allow intervening "clean" and vegetated soils to
intercept erosion and runoff from the compost-amended 10 acres prior to its reaching the lake.)
As a consequence, the SSW Model estimated substantial erosion and runoff of chemicals into the
lake, where the inorganics in water were accumulated in fish (e.g., Table 5.3.12 in the main
report).
For burial, we focus on the first year of leaching to groundwater, because the quantity of
chemicals in leachate is highest during the first year; lower quantities of chemical remain in the
burial trench over subsequent years. We did not calculate chemical-specific leaching rate
E-3
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
constants to estimate the declining chemical quantities leaching each year for the 20 to 30
following years (see main report, Section 3.4.1, Table 3.4.3). The approach used to estimate the
degree to which subsurface soils filter out a fraction of each chemical (i.e., chemical in leachate
or in percolating water sorbs to soil particles) is described in Section 4.3.1 of the main report.
For the combustion-based options, we estimate leaching from buried bottom ash over the first
year after the ash burial with similar methods.
E.3. Fate and Transport Modeling Outputs
The fate and transport processes included in the SSW Screening Model are characterized using
equations representing mass transfer of chemicals to or from environmental media (i.e., chemical
loading to or chemical loss from the watershed soil and the water body) or partitioning among
phases (e.g., particle and aqueous phases) within each major environmental medium. Chemical
loading equations are expressed as the change of mass of chemical per unit area in one year.
Chemical losses from erosion of surface soils and runoff are represented as a first-order rate
constant per year; SSW moves those losses into the surface water (lake). Additionally, PAHs are
subject to congener-specific abiotic/biotic degradation represented as first-order rate constants.
Elements cannot be "degraded," and 2,3,7,8-substituted dioxins and furans biodegrade very
slowly if at all. The algorithms and parameters included in the SSW Screening Model are derived
from - and in many cases, identical to - the equations and parameters presented in HHRAP
(USEPA 2005). For clarity, equation and parameter terminology and symbols used in the SSW
Screening Model are consistent with those included in HHRAP whenever possible (see
Appendix F. for parameter symbols).
We present an overview of most of the fate and transport processes modeled in the SSW
Screening Model (not including bioaccumulation) in Figure E.l. For the combustion-based
management options, chemical gains to the watershed soils and the water body can occur
directly, via direct air deposition of particle-bound chemical to the ground or water's surface or
via diffusion of vapor-phase chemical into surface soils or surface water. Further loading to the
water body can occur indirectly through subsequent watershed transfers to the water body via
erosion and runoff. In addition to calculating chemical concentrations in the surface soil
E-4
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
following deposition, the SSW estimates losses from the watershed soils via runoff, erosion,
leaching, and volatilization to estimate concentrations after one (or more) years.
For composting, we examine two phases. The first is possible leaching of decomposition
products from the initial compost rows, which are covered a 0.6 m thick layer of woodchips and
underlain by 0.6 m of woodchips. The second phase follows application of that compost to
agricultural fields on-site. Amended soils might have higher concentrations of some chemicals
(e.g., carbon, nitrogen, and heavy metals) that could affect lake ecosystems if there is substantial
erosion or runoff from the amended soils to the lake.
The loading rates for compost application are limited to the portion of the watershed (10 acres)
that would receive compost application with the finished compost applied at an agronomic rate
(see Section 3.5 of the main report). The total of all chemicals applied per m2 when the finished
compost is amended to 10 acres of agricultural soil is used to estimate all chemical
concentrations based on a horizontal 10-acres (4.05 hectares or 40,500 m2) area and 20 cm depth
for compost tilled into the soil. Those values serve as the concentration at time 0 for the amended
soil, and the SSW Screening Model calculates subsequent movement of chemical via erosion,
runoff, and volatilization for the year.
The final chemical concentrations in the amended soils following one year of losses provide the
annual average soil concentration. The chemical mass on soil particles eroded to the lake is
added to the lake sediments, and chemical mass in surface runoff is added to the lake water
column. Chemical mass that leached from a source (calculated outside of the SSW as described
in Section 4.3.1 of the main report) over one year also is subtracted from the 10 acres of
amended soil. The bulk of vapor-phase chemicals formed during decomposition in the windrow
is lost while the windrow is intact; therefore negligible volatilization of chemicals from compost-
amended soils is expected.
For the combustion-based management options, vapor-phase and particle-phase deposition rates
calculated by AERMOD are input to the SSW Screening Model which calculates total
concentrations in soils over the 500 acre watershed. Then, the SSW predicts the fraction of each
chemical deposited that erodes or runs off into the lake. SSW outputs include: (1) the total
chemical concentrations in the lake water column including dissolved chemical and chemical
E-5
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters —Appendices
sorbed to suspended solids, and (2) the total chemical concentration in the bulk benthic sediment,
including (a) chemical bound to sediment particles and (b) freely-dissolved chemical
concentration in the sediment-associated pore (or interstitial) water.
For the combustion-based management options, possible contributions from precipitation
percolating through buried ash to groundwater, and then reaching the lake, are added to the water
column concentrations to estimate the final concentrations in the lake. As discussed in Section
4.5 of the main report, those concentration estimates are used to estimate chemical
concentrations in fish tissues (see Appendices J and K).
Erosion Losses
Leaching Losses
Runoff Losses
Volatilization Losses
/Depi
*
Deposition
^^Erosion \ Runoff
Air
Diffusion
Deposition
Outflow/Water body
Flush Losses
Volatilization Losses
Water Body
Sediment Burial Losses
~
Figure E.l. SSW Screening Model fate and transport conceptual diagram.
For organic compounds, we estimate fish tissue concentrations with a companion steady-state
equilibrium model, AQUAWEB, described in Appendix J (a biokinetic model for lipophilic
organics; Arnot and Gobas 2004; AQUAWEB 2005). For inorganic chemicals, and fish tissue
E-6
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
concentrations are estimated with bioaccumulation factors documented in Appendix K. applied
to the dissolved chemical concentration (not total chemical concentration). In AQUAWEB,
chemicals sorbed to suspended sediment particles are not available for uptake via gills of water-
column fish or invertebrates.
After total chemical loading to the water body is accounted for, losses via volatilization from
surface water and via benthic sediment burial are calculated to estimate the "total water body
concentration," inclusive of both the water column and sediment, after one (or more) year(s).
Chemical concentrations in the water body that are needed for bioaccumulation calculations (i.e.,
chemical concentrations in the water column and in sediment) are then calculated based on the
assumption of equilibrium partitioning between the water column and benthic sediment and
between the dissolved and particle-sorbed phases in each of these compartments. Using the
symbols and terminology included in the SSW Screening Model spreadsheets, the loading to the
water body is expressed in Equation E. 1.
where:
L T = L DEP + L dif + L RI + L R + L E + L G (Eqn. E.l)
L T = Total chemical load to the water body (g/yr),
L DEP= Deposition load to the water body (g/yr),
L dif = Vapor-phase diffusion load to the water body (g/yr),
L RI = Runoff load from impervious surfaces (g/yr),
L R = Runoff load from pervious surfaces (g/yr),
L E = Soil erosion load to the water body (g/yr), and
L G = Groundwater recharge load to the water body (g/yr).
This is identical to the equation in HHRAP Table B-4-7 except for the addition of a contribution
from groundwater, which is not included in HHRAP. The methods and assumptions used to
estimate the rate of groundwater recharge to the on-site lake are discussed in Section 4.3 of the
main report.
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
For equations for each source of loading in Equation E.l, as well as equations for estimating soil
concentrations from deposition rates (including compost application), refer to the HHRAP
documentation (USEPA 2005).
E.4. Parameterization
The HHRAP SSW Screening Model requires several dozen environmental and chemical
parameter values to calculate concentrations in soils, surface water, and sediments (see Appendix
F. ). For organic chemicals, AQUAWEB requires additional environmental and chemical-
specific biotic and abiotic parameter values to estimate bioaccumulation of chemicals in fish. To
minimize set-up time and conduct model runs, sets of default values were developed for many of
the parameters. USEPA developed default parameter values for the HHRAP SSW portion of the
model. Abiotic inputs to the AQUAWEB model of bioaccumulation (i.e., concentrations of
organic chemicals in the water column and sediments) were those estimated by the SSW portion
of the model. For organic chemicals, AQUAWEB also estimated chemical-specific biological
parameter values and final fish tissue concentrations using chemical octanol-water partitioning
coefficient (Kow) and the aquatic food web as specified for this project. For inorganic chemicals,
values for bioaccumulation factors in fish are as reported in the literature (Appendix K).
Appendix F lists the default values and other input parameter values for SSW. USEPA selected
many of the parameter values for HHRAP. Where uncertainties were large or natural variability
is high, USEPA selected somewhat conservative values to ensure that the model can be
successfully used as intended (i.e., as a screening tool). For parameters for which USEPA did not
recommend values for a national assessment, values were selected based on the same principal:
to err on the conservative side where uncertainties are present to avoid underestimating the risks.
We used Arnot and Gobas (2004) AQUAWEB (2005, available online) to estimate
bioaccumulation of nonionic organic chemicals in fish from the chemical concentrations in the
water column and in the sediments calculated by the SSW Screening Model (including any
additional quantities that might reach the lake from buried ash for the two on-site combustion
options). Although USEPA developed an online version of the model, KABAM, for use in
pesticide evaluations, that version allows processing of only one chemical at a time, and requires
the user to input chemical-specific parameter values one-by-one in a series of input data screens.
E-8
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
AQUAWEB allows specification of all parameter values for up to 25 chemicals in an Excel™
spreadsheet, and the results are available immediately in table format for all 25 chemicals to
facilitate comparisons.
This assessment uses a different aquatic food chain and several different environmental
parameter values than those included in the online version of AQUQWEB for Lake Erie. We
selected the values to be more representative of small to medium U.S. lakes. Appendix H
presents the abiotic parameter values and rationale for their selection for input to the SSW and
AQUAWEB. Appendix J presents the parameter values and rationale for their selection for the
biotic components of AQUAWEB, including our definition of a food web that might occur in a
100-acre lake (Table J.5).
E.5. References
Arnot JA, Gobas FAPC (2004). A food web bioaccumulation model for organic chemicals in
aquatic ecosystems. Environmental Toxicology and Chemistry 23(10): 2343-2355.
AQUAWEB (2005). Burnaby, BC, Canada: Simon Fraser University; 2005 November 23.
USEPA (U.S. Environmental Protection Agency). 2005. Human Health Risk Assessment
Protocol for Hazardous Waste Combustion Facilities (HHRAP), Final. Washington, DC: U.S.
Environmental Protection Agency, Office of Solid Waste. September. EPA/520/R-05/006.
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Appendix F. Detailed Parameter Documentation Tables for the HHRAP
SSW Excel™ Model
The main report lists the parameter values that were used as input to the HHRAP-based SSW
Excel model. Where data or estimated parameter values were obtained from based on empirical
equations developed by others, the source is cited (final column). For those parameter values for
which the source is listed as "Assumed," the rationale is described in Section F.2, by parameter.
F.l. Input Parameter Values
Table F.l. Parameters for the HHRAP SSW Excel Model.
Inputs
Input Value
Units
Variable
Name
Source for Default Value
0.0) Time period at beginning of
emissions
0
yr
T_1
HHRAP (USEPA 2005)
0.1) Time period over which
deposition occurs
1
yr
tD
HHRAP (USEPA 2005)
0.2) Length of exposure duration
1
yr
TJj
HHRAP (USEPA 2005)
0.3) Temperature
8.34
°C
Tmp
Average air temperature for
Iowa; see main report Section
2.3.1
1. Characteristics of On-site Lake
1.1) Water body surface area
404,686
mA2
A w
Assumed (100 acres)
1.2) Total watershed area
- for open pyre, ACB, and burial
- for compost application
2,020,191
40,469
mA2
A_L
Assumed: calculated as 5 times
the lake surface area (0.8 and
0.0156 square miles,
respectively)
1.3) Maximum depth of lake
25
ft
d max
Median depth of lakes in
Minnesota, for which an
extensive lake database is
available online
1.4) Average water body depth
4.38
m
d wc
Calculated from maximum
depth and surface area as per
Schupp (1992)
1.5) Cross-sectional area of lake
2784
mA2
CA_w
Calculated from surface area
and average depth
1.6) Annual evaporation of water
body
0.60
m/yr
E loss
Geraghty et al. (1973)
1.7) Sediment organic carbon
content
0.04
unitless
OC sed
and
f ocbs
HHRAP (USEPA 2005), App
B, p B-274
1.9) Dissolved oxygen content
9.50
mgOi/L
DOC
Calculated from SAT - see
AQUAWEB documentation
1.10) Depth of upper benthic
sediment layer
0.03
m
d bs
HHRAP (USEPA 2005), App
B, p B-228 (range 0.01 to 0.05)
1.11) Sediment delivered to
waterbody
calculated
kg
soil/mA2-
yr
SD_X_e
Product of the sediment
delivery ratio (SD) and the unit
soil loss (A' e ) in mg/m2-yr
F-l
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Inputs
Input Value
Units
Variable
Name
Source for Default Value
1.12) Sediment delivery empirical
intercept coefficient
1.9
[open pyre,
ACB, burial]
2.1
[composting]
unitless
a sed
Depends on watershed size;
1.9 for watershed between 0.1-
1.0 square miles and 2.1 for
smaller watersheds; Vanoni
1975 cited inHHRAP (USEPA
2005), App B, p B-223
1.13) Sediment delivery empirical
slope coefficient
0.125
unitless
b sed
Constant value; Vanoni 1975
cited in HHRAP (USEPA
2005), App B, p B-223
1.14) Drag coefficient
0.0011
unitless
C_d
HHRAP (USEPA2005), App
B, p B-246
1.15) Dimensionless viscous
sublayer thickness
4
unitless
X z
HHRAP (USEPA 2005), App
B, p B-247
1.16) Von Kannan's constant
0.4
unitless
k vk
HHRAP (USEPA 2005), App
B, p B-246
1.17) Water density
(specific gravity)
1.00
g/cmA3
p vc
Pure water (no dissolved
substances) highest density at
4°C (39.2°F); limited variation
with temperature when liquid
1.18) Water viscosity
(poise = g/cm-s)
1.31E-02
g/cm-s
f.1 vc
HHRAP (USEPA 2005), App
B, p B-247; cites Weast 1979;
decreases with increasing
temperature [1.69E-02 at 25°C
and 1 atm pressure]
1.19) Temperature correction factor
1.026
unitless
e
HHRAP (USEPA 2005), App
B, p B-243
2. Atmospheric Parameter Values
2.1) Average annual wind speed
4.13
m/s
w
Based on Iowa data for 2014;
see main report Section 2.3.1
2.2) Air viscosity
1.72E-04
g/cm-s
f.i a
At air temperature of 6°C
2.3) Air density
1.27E-03
g/cmA3
p a
At temperature of 6°C
2.4) Universal gas constant
8.21E-05
atm-
mA3/mol-
K
R_gas
HHRAP (USEPA 2005), App
B, p B-29
2.5) Dry particle deposition
velocity
0.15
cm/s
u _pdep
Assumed; consistent with
semivolatile chemicals
2.6) Dry vapor depositional
velocity
1.5
cm/s
u vdep
Assumed; conservative
estimate consistent with value
for nitric acid vapor
3. Soil & Watershed
Parameters
3.1) Fraction (proportion) of
watershed that is impervious
0.05
unitless
A I Fra
c
Minimal impervious surfaces;
assume 5%
3.2) Fraction of precipitation that is
evapotranspired by plants
0.80
unitless
f evap
Calculated; USGS 1994
3.3) Soil mixing zone depth:
-Tilled soil [for composting]
-Untilled Soil [other options]
20
2
cm
cm
Z s
HHRAP (USEPA 2005), App
B, p B-5
3.4) Fraction organic content, soil
0.01
unitless
f ocs
HHRAP (USEPA 2005)
3.5) Soil volumetric water content
0.20
mL/cmA3
6 svc
HHRAP (USEPA 2005), App
B, p B-16
F-2
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Inputs
Input Value
Units
Variable
Name
Source for Default Value
3.6) Soil bulk density
1.50
g
soil/cmA3
soil
BD
HHRAP (USEPA 2005), App
B, p B-15, based on loam soil
3.7) Solids particle density
2.7
g/cmA3
p soil
HHRAP (USEPA 2005), App
B, p B-30 based on Blake and
Hartage (1996) andHillel
(1980)
3.8) Soil enrichment ratio (organic
chemical)
3
unitless
ER
HHRAP (USEPA 2005), App
B, p B-15,
3.9) Soil enrichment ratio
(inorganic chemical)
1
unitless
ER
HHRAP (USEPA 2005), App
B, p B-15,
3.10) Universal Soil Loss Equation
(USLE)
10.24
tons/acre-
year
X_e
Calculated using equation B-4-
13 in HHRAP (USEPA 2005),
App B, p 219
3.11) USLE erodibility factor
0.39
ton/acre
K erode
Assumed; value of 0.39 is
typical/conservative of average
soil types
3.12) USLE length-slope factor
0.050
unitless
LS
As per client request;
corresponds to a slope of 5%
3.13) USLE supporting practice
factor
1.00
unitless
PF
Value of 1 assumes no
supporting practices such as
contour tillage, terracing, cover
crop, or crops in place
3.14) USLE cover management
factor
0.3
unitless
C var
Assumed; values for croplands
range from 0.05 to 0.5
3.15) Average evapotranspiration
77.66
cm/yr
E_v
Calculated as the product of
annual precipitation and the
fraction evapotranspired
4. Groundwater
4.1) Aquifer Hydraulic
Conductivity
11.12
cm/yr
GWtoSW
= 0.001 fit/day, selected based
on Heath (1983), fig p 13
4.2) Residual water leached to
groundwater
calculated
cm/yr
TW
Calculated; equation provided
in Section E.2 - defaults to
zero if water balance is
negative
Abbreviations: A = raised to the power of (number following); ACB = air-curtain burning; App = Appendix; atm = atmospheres;
°F = degrees Fahrenheit; fig = figure; ft = feet; HHRAP = Human Health Risk Assessment Protocol for Hazardous Waste
Combustion Facilities; K = Kelvin; mol = moles; O2 = oxygen; s = seconds; USLE = Universal Soil Loss Equation.
F.2. Rationale for Assumed Parameter Values
F-l.l. Surface Area of Lake = 100 acres. Prior to making any estimates of environmental
concentrations that might result from management of 50 tons of livestock carcasses, it was
decided to include a 100-acre lake to ensure that it was large enough to include sustainable
populations of higher trophic level fish. Fish consumption from the lake, then, would be
sustainable even with a 10% harvest rate by subsistence fishermen (report under development).
This size lake has been included in analyses of commercial point sources of essentially
F-3
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
continuous emissions to air over 30 years or more. Based on this analysis, it was concluded that a
smaller lake (e.g., 10 to 25 acres) might also provide sustainable fish populations at the much
lower fish ingestion rates assumed for farmers in the carcass management scenarios.
Smaller lakes would provide less dilution for the unlined burial and compost applied to a field,
resulting in higher surface-water concentrations for that option than with the current 100-acre
lake assumption. For the open pyre and air-curtain burning options, a smaller lake would provide
less dilution, but have a smaller watershed associated with it (assuming a 1:5 ratio [surface water
area]:[watershed area]). On balance, however, higher surface water concentrations would be
expected for the combustion-based management options for a smaller lake because of the
reduced dilution. Similarly, if the quantity of livestock carcasses managed in a single location
(e.g., single pyre, single burial pit) were higher, chemical concentrations in all environmental
media near the site would be higher.
In reality, however, lake concentrations are likely to be lower than estimated for the four on-site
scenarios considered in this project (burial, composting, open pyre and air-curtain burning),
because the assessment assume no lake outflow via streams or recharge to groundwater. SSW
Screening Model did simulate chemical losses from volatilization from the lake and from
sediment burial. In reality, there tend to be groundwater inflows and outflows, and often
significant stream outlets that become evident during rain events. Those processes would reduce
chemical concentrations in a lake.
For compost application to soils, on the other hand, farmers should limit the loading rate per unit
area based on the concentrations of nitrogen and possibly phosphorus in the finished compost.
The SSW Screening Model did not allow separation of the area of compost application from the
surface water (they must be considered to be adjacent). In reality, farmers probably would be
allow at least a 100-ft buffer between a field receiving livestock-carcass finished compost, and
their lake's surface water. Allowing any distance in this assessment would have reduced surface
water concentrations of inorganic chemicals relative to those estimated for other carcass
management methods in this report. Thus, the effect of compost application on surface water
concentrations would depend not only on the size of the lake, but also on the orientation and
shape of the area where the compost was applied.
F-4
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Burial would continually need more land area if there was a need for ongoing carcass
management on-site because of the need to not disturb existing trenches. Composting could reuse
areas, if enough time to ensure adequate decomposition elapsed before adding more carcasses to
the windrows. Burial of ash from either open pyre or air-curtain burning would affect the least
land-surface area over the long-term, but other land uses are likely to be suspended while
combustion activities and air-emission plume effects prevail.
F-1.2 Total watershed area = 500 acres (2,020,191 in2) for open pyre, ACB, and burial (0.8
square miles). The size and shape of a watershed that supplies water and sediments to given lake
depends on local geography, including ground elevation profiles and the number and type of
creeks or streams that might enter the lake. For purposes of the scenarios, it was necessary
assume a set watershed surface area. Watershed or drainage basin/lake area ratios (DB:LA) of
4:1 have been called "small" (Freedman 1995, p 125) and ratios of 19:1 called large
(www.lakeviz.org/ourlakes/). In general, lakes with small DB:LA ratios have longer water
retention times, with small DB:LA ratios of 6 corresponding with a retention time of over 2 years
(Lillie and Mason 1983; Table 1 in Shaw et al. 2004). A DB:LA ratio of 5 was assumed to be
consistent with the assumption of long retention time.
F-1.2b Total watershed area = 10 acres (40,469 in2) for composting (0.0156 square miles).
This calculated area is inaccurately termed a watershed, and is used as a surrogate to model the
10 acre area receiving an application of finished compost. This is a way to input a smaller
acreage into the SSW Screening Model to simulate a 10-acre area of applied compost next to the
lake.
F-2.5. Particle dry deposition velocity. Typically metals are emitted as primary particles (in
particle form at the time of release), and the size distribution is characteristic of the mass size
distribution of particle emissions from the source. On the other hand, most semi-volatiles tend to
be in the gas phase at the time of release and condense onto pre-existing particles as the plume
cools. The semi-volatiles thus tend to be associated with particles according to the surface area
available for condensation. The surface area of particle emissions is weighted towards smaller
particles than the mass size distribution, so the semi-volatiles will preferentially be found on
smaller particles. The distribution of particle sizes in which or upon which a chemical is found
affects the surface boundary resistance and thereby the deposition velocities that are expected.
F-5
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Deposition velocities measured in Minnesota (Pratt et al. 1996) ranged from 0.09-0.15 cm/s for
fine particles (nominal diameter cutpoint of PM2.0), 0.28-0.42 cm/s for sulfur dioxide and 0.83-
1.46 cm/s for nitric acid vapor. Since the surface area distribution of particles from a typical
combustion source would typically peak in the fine particle range, using the upper bound on the
fine particle deposition velocity (say 0.15 cm/s) would be a reasonable starting point deposition
velocity for the semivolatile substances such as PAHs and dioxins/furans. A somewhat higher
value (perhaps in the range of 0.2 cm/s) would be a reasonable value for the metals, since they
may be associated with larger particle sizes. For the combustion-based carcass management
options, however, we assume 0.15 cm/s for all particle deposition in the HHRAP-based SSW
model. The value assumed for particle settling in the SSW model does not affect the total amount
of chemical deposited per m2 over the 48-hr burn, however, which is calculated by AERMOD.
F-2.5. Vapor dry deposition velocity. We assume a dry vapor deposition velocity of 1.5 cm/s to
ensure that the SSW model will run. Again, that does not affect the total chemical deposited per
m2 which is calculated by AERMOD.
F-3.11. Universal Soil Loss Equation (USLE) erodibility factor. Specific soil types have
different natural susceptibilities to erosion, depending on the specific makeup of their
components (Wischmeier and Smith 1978). The soil-erodibility factor (K erode) is used to
specify the ease with which soil on a given field is eroded. A value of 0.39 was selected, which is
slightly higher than the average value, for surface soils including the compost-amended soil over
10 acres. The compost windrow has an erodibility factor of zero.
F-3.13. USLE supporting practice factor. Supporting practices include contour tillage,
stripcropping on the contour, and terracing and is used in calculations of runoff and erosion (not
leaching). A value of 1 assumes no supporting practices. It is unlikely that users will have need
to provide a USLE supporting practice factor (PF) value different from the default (PF = 1), as it
is unlikely that an entire watershed will have significant supporting practices to reduce erosion.
The cover management factor (C var) represents the influence of the type of plants and other
matter on the ground of a slope. The type of ground cover present on a field plays a major factor
in determining the amount of soil eroded from a slope. Values of the cover management factor
can range from less than 0.001 for dense grasses and undisturbed forestland to 1 for bare
construction sites. Values for cropland typically range from 0.05 to 0.5, depending on tillage and
F-6
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
crop type. For the compost windrow, the PF value is set to 0 (i.e., no erosion) and for the
compost-amended soil (10 acres) the PF is set to 1 (note that the shallow slope of 5% limits
surface soil/applied-compost erosion).
F-3.14. USLE cover management factor. Values for the cover management depend on the type
of tillage and species of crops. Some information on defining the cover management factor is
available online at topsoi 1.nserl.purdue.edu/usle/AH 537.pdf.
F.3. References
Blake GR, Hartge KH (1986). Particle Density. Chapter 14 in: Methods of Soil Analysis, Part 1:
Physical andMineralogicalMethods. Second Edition (A Klute, ed). Madison, WI: American
Society of Agronomy, Inc.; p. 381.
Freedman B (1995). The Ecological Effects of Pollution, Disturbance, and Other Stresses.
Chapter 1 In: Environmental Ecology. Second Edition. (B Freedman, ed). San Diego, CA:
Academic Press Inc, Division of Harcourt Brace & Company.
Geraghty JJ, Miller DW, Van der Leeden F, Troise FL (1973). Water Atlas of the United States.
Port Washington, NY: Water Information Center.
Heath RC (1983). Basic Ground-Water Hydrology. U.S. Geological Survey Water-Supply Paper
2220. Washington, DC: U.S. Dept. of the Interior. Accessed September 21, 2015 from:
http://pubs.er.usgs.gov/divuAVSP/wsp 2220.pdf.
Hillel D (1980). Fundamentals of Soil Physics. New York: Academic Press, Inc.
Lillie RA, Mason JW, Hine RL (eds) (1983). Limnological Characteristics of Wisconsin Lakes.
Madison, WI: Wisoconsin Department of Natural Resources Technology Bulletin No. 138. Cited
by Shaw et al. (2004).
Pratt GC, Orr EJ, Bock DC, Strassma RL, Fundine DW, Twaroski CJ, Thornton JD, Meyers TP
(1996). Estimation of dry deposition of inorganics using filter pack data and inferred deposition
velocity. Environmental Science and Technology 30(7): 2168-2177.
F-7
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Schupp DH (1992). An Ecological Classification of Minnesota Lakes with Associated Fish
Communities. St. Paul, MN: Minnesota Department of Natural Resources, Section of Fisheries
Investigational Report 417.
Shaw B, Mechenich C, Klessig L (2004). Understanding Lake Data (G3582). Madison, WI:
Cooperative Extension Publishing Operations, University of Wisconsin System. RP-03/2004.
Retrieved February 2, 2016, from http://www3.uvvsp.edu/cnr-ap/weal/Documents/G3582.pdf.
USEPA (U.S. Environmental Protection Agency) (2005). Human Health Risk Assessment
Protocol for Hazardous Waste Combustion Facilities (HHRAP). Washington, DC: U.S.
Environmental Protection Agency, Office of Solid Waste. September. Final. EPA-520/R-05-006.
USGS (U.S. Geological Survey) (1994). Ground-Water Discharge by Evapotranspiration in a
Desert Environment of Southern Nevada, 1987. Water-Resources Investigations Report 94-4124.
Denver, CO: U.S. Geological Survey.
Vanoni, VA (1975). Sediment Engineering. New York: American Society of Civil Engineers, pp
460-463.
Wischmeier WH, Smith DD (1978). Predicting Rainfall Erosion Losses - A Guide to
Conservation Planning. USDA Handbook 537. Washington, DC: U.S. Dept. of Agriculture.
F-8
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Appendix G, Supporting Information for Chemical Leaching
from Burial, Composting, and Carcass Storage
Table G.l through Table G.3 show the estimation of chemical-specific concentrations in drinking
water for leaching from the carcass burial option and three time periods, based on leaching data
from Pratt and Fonstad (2009). Table G.4 and Table G.5 show similar calculations for leaching
from the temporary carcass storage pile and the compost windrow. Table G.6 provides a legend
to the calculation columns in the tables.
G.l. References
Pratt DL, Fonstad TA (2009) Livestock mortalities burial leachate chemistry after two years of
decomposition. 3rd International Symposium on Management of Animal Carcasses, Tissue, and
Related By-products, June 21-24, 2009; Reno, NV.
Young C, Marsland P, Smith JWN (2001). Foot and Mouth Disease Epidemic. Disposal of
culled stock by burial: Guidance and Reference Data for the protection of controlled waters.
Draft R&D Technical Report V7. Swindon, UK: Environment Agency R&D Dissemination
Centre; 70 pp.
G-l
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Table G.l. Estimated Leaching and Well Water Concentration of Chemicals from Buried Carcasses During the First Week.a'b
A
B
C
D
E
F
G
Chemical
Avg Cone.
First Week
(mg/L)
Kd (L/kg)
Total Released
First Week (mg)
Total Filtered Back to
Soil from Leachate
First Week (mg)
Total Reaching
Groundwater
(mg)
Intercepted by
0.2 m Well Per
Day, First Week
(mg/d)
Avg Cone. In
Drinking
Water, First
Week (mg/L)
1136 L/d
aluminum
1.7E+00
1.5E+03
1.3E+04
1.3E+04
2.2E-01
6.8E-05
6.0E-08
ammonium
5.2E+03
1.4E-01
3.9E+07
3.3E+07
5.9E+06
1.9E+03
1.6E+00
barium
3.0E-01
4.1E+01
2.3E+03
2.2E+03
1.4E+00
4.4E-04
3.9E-07
beryllium
0.0E+00
7.9E+02
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
bicarbonate
3.5E+04
1.0E-02
2.6E+08
7.4E+07
1.9E+08
5.9E+04
5.2E+01
boron
0.0E+00
1.4E-01
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
cadmium
0.0E+00
7.5E+01
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
calcium
6.0E+01
1.4E-01
4.5E+05
3.8E+05
6.9E+04
2.1E+01
1.9E-02
chloride
2.6E+03
1.4E-01
2.0E+07
1.7E+07
3.0E+06
9.3E+02
8.2E-01
chromium
0.0E+00
1.9E+01
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
cobalt
1.0E-01
4.5E+01
7.5E+02
7.5E+02
4.3E-01
1.3E-04
1.2E-07
copper
6.0E-01
4.3E+02
4.5E+03
4.5E+03
2.7E-01
8.4E-05
7.4E-08
inorganic C
6.9E+03
—
5.2E+07
0.0E+00
5.2E+07
1.6E+04
1.4E+01
organic C
4.3E+04
—
3.2E+08
0.0E+00
3.2E+08
1.0E+05
8.9E+01
iron
1.1E+02
6.5E+01
8.3E+05
8.2E+05
3.3E+02
1.0E-01
9.0E-05
lead
0.0E+00
9.0E+02
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
magnesium
3.0E+01
1.4E-01
2.3E+05
1.9E+05
3.4E+04
1.1E+01
9.4E-03
manganese
5.0E-01
6.5E+01
3.8E+03
3.7E+03
1.5E+00
4.6E-04
4.1E-07
mercury
0.0E+00
2.0E-01
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
molybdenum
1.8E+00
1.4E-01
1.4E+04
1.1E+04
2.1E+03
6.4E-01
5.7E-04
nickel
4.0E-01
6.5E+01
3.0E+03
3.0E+03
1.2E+00
3.7E-04
3.3E-07
nitrate/nitrite
2.3E+01
1.4E-01
1.7E+05
1.5E+05
2.6E+04
8.2E+00
7.2E-03
total N
1.8E+04
—
1.4E+08
0.0E+00
1.4E+08
4.3E+04
3.8E+01
phosphorus
9.2E+02
1.4E-01
6.9E+06
5.8E+06
1.1E+06
3.3E+02
2.9E-01
potassium
1.9E+03
1.4E-01
1.4E+07
1.2E+07
2.2E+06
6.8E+02
6.0E-01
selenium
0.0E+00
5.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
G-2
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
A
B
C
D
E
F
G
Chemical
Avg Cone.
First Week
(mg/L)
Kd (L/kg)
Total Released
First Week (mg)
Total Filtered Back to
Soil from Leachate
First Week (mg)
Total Reaching
Groundwater
(mg)
Intercepted by
0.2 m Well Per
Day, First Week
(mg/d)
Avg Cone. In
Drinking
Water, First
Week (mg/L)
1136 L/d
silicon
2.9E+01
1.4E-01
2.2E+05
1.8E+05
3.3E+04
1.0E+01
9.1E-03
silver
0.0E+00
8.3E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
sodium
1.6E+03
1.4E-01
1.2E+07
1.0E+07
1.8E+06
5.7E+02
5.0E-01
strontium
7.0E-01
1.4E-01
5.3E+03
4.4E+03
8.0E+02
2.5E-01
2.2E-04
sulphate
3.7E+03
6.1E-02
2.8E+07
2.0E+07
8.2E+06
2.6E+03
2.3E+00
sulphur
1.2E+03
1.4E-01
9.0E+06
7.6E+06
1.4E+06
4.3E+02
3.8E-01
titanium
2.0E-01
1.4E-01
1.5E+03
1.3E+03
2.3E+02
7.1E-02
6.3E-05
vanadium
0.0E+00
1.0E+03
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
zinc
3.5E+00
6.2E+01
2.6E+04
2.6E+04
1.1E+01
3.4E-03
3.0E-06
zirconium
2.0E-01
1.4E-01
1.5E+03
1.3E+03
2.3E+02
7.1E-02
6.3E-05
Abbreviations: "—" = not available; Kd = soil-water partitioning coefficient; NA = not analyzed; nd = not detected.
a See Section 4.3.1 of the main report for a description of the methods and calculations used to estimate leaching from buried carcasses to ground water and to estimate maximum
likely chemical concentrations in groundwater as drawn up the well for household uses. Original leachate concentration data are from Pratt and Fonstad (2009). Leachate
accumulated on top of 40 mil liner of pit, thus, concentrations of most chemicals increased over time as the carcasses continued to decompose. Exceptions include chemicals that
might have off-gassed through the vent pipe and some that might have precipitated out of solution or sorbed to particles over time. Additional sampling dates included Nov 23,
2005, May 25, 2006, and October 26,2006.
b As described in main report, Section 3.4, the initial fresh carcass weight = 45,359 kg. Young et al. (2001) estimated that 60% of a buried mammalian corpse degrades in the first
year; 33% of the carcass mass is released during the first two months after burial; and half of that is released in the first week. Based on those estimates, the quantity of leachate
released in the first week = 7,500 L was calculated; over the next 8-10 weeks = 15,000 L; and in the first year = 27,000 L. To estimate the total mg of chemical released over the
first week (column I), concentrations from the first sample (August 17, column B) were multiplied by 7,500 L. To estimate the total mg of chemical released over the first 8-10
weeks (column J), the average concentration over the first three sampling dates (column D) was multiplied by 15,000 L. To estimate the total mg of chemical released over first
year (column K), the average concentration over the first 12 months (column E) was multiplied by 27,000 L.
G-3
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Table G.2. Estimated Leaching and Well Water Concentration of Chemicals from Buried Carcasses During the First Two
Months.a'b
A
B
C
D
E
F
G
Chemical
Avg Cone
First Two
Months
(mg/L)
Kd (L/kg)
Total Released
First Two
Months (mg)
Total Filtered Back to
Soil from Leachate
First Two Months
(mg)
Total Reaching
Groundwater
(mg)
Intercepted by
0.2 m Well Per
Day, First Two
Months (mg/d)
Avg Cone In
Drinking
Water, First
Two Months
(mg/L) 1136
L/d
aluminum
1.5E+00
1.5E+03
2.2E+04
2.2E+04
7.5E-01
2.7E-05
1.0E-04
ammonium
7.7E+03
1.4E-01
1.2E+08
8.5E+07
3.1E+07
1.1E+03
0.0E+00
barium
4.7E-01
4.1E+01
7.0E+03
7.0E+03
8.8E+00
3.2E-04
4.7E-03
beryllium
0.0E+00
7.9E+02
0.0E+00
0.0E+00
0.0E+00
0.0E+00
3.3E-01
bicarbonate
4.0E+04
1.0E-02
5.9E+08
9.7E+07
5.0E+08
1.8E+04
0.0E+00
boron
8.0E-01
1.4E-01
1.2E+04
8.8E+03
3.2E+03
1.2E-01
0.0E+00
cadmium
0.0E+00
7.5E+01
0.0E+00
0.0E+00
0.0E+00
0.0E+00
5.2E-08
calcium
3.7E+01
1.4E-01
5.5E+05
4.0E+05
1.5E+05
5.3E+00
3.8E+00
chloride
2.6E+03
1.4E-01
3.9E+07
2.9E+07
1.0E+07
3.7E+02
2.2E+01
chromium
0.0E+00
1.9E+01
0.0E+00
0.0E+00
0.0E+00
0.0E+00
2.5E-05
cobalt
0.0E+00
4.5E+01
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
copper
9.0E-01
4.3E+02
1.4E+04
1.3E+04
1.6E+00
5.9E-05
3.0E-03
inorganic C
7.8E+03
—
1.2E+08
0.0E+00
1.2E+08
4.3E+03
1.5E-07
organic C
4.5E+04
—
6.8E+08
0.0E+00
6.8E+08
2.5E+04
0.0E+00
iron
6.6E+01
6.5E+01
1.0E+06
9.9E+05
7.9E+02
2.9E-02
8.5E-05
lead
0.0E+00
9.0E+02
0.0E+00
0.0E+00
0.0E+00
0.0E+00
9.5E-08
magnesium
2.3E+01
1.4E-01
3.5E+05
2.6E+05
9.3E+04
3.4E+00
1.7E-03
manganese
4.0E-01
6.5E+01
6.0E+03
6.0E+03
4.7E+00
1.7E-04
7.3E+00
mercury
0.0E+00
2.0E-01
0.0E+00
0.0E+00
0.0E+00
0.0E+00
1.5E-01
molybdenum
6.7E-01
1.4E-01
1.0E+04
7.4E+03
2.6E+03
9.6E-02
2.6E-01
nickel
2.5E-01
6.5E+01
3.8E+03
3.7E+03
3.0E+00
1.1E-04
0.0E+00
nitrate/nitrite
1.3E+01
1.4E-01
2.0E+05
1.4E+05
5.2E+04
1.9E+00
3.4E-03
G-4
-------
Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
A
B
C
D
E
F
G
Chemical
Avg Cone
First Two
Months
(mg/L)
Kd (L/kg)
Total Released
First Two
Months (mg)
Total Filtered Back to
Soil from Leachate
First Two Months
(mg)
Total Reaching
Groundwater
(mg)
Intercepted by
0.2 m Well Per
Day, First Two
Months (mg/d)
Avg Cone In
Drinking
Water, First
Two Months
(mg/L) 1136
L/d
total N
1.5E+04
—
2.3E+08
0.0E+00
2.3E+08
8.3E+03
0.0E+00
phosphorus
1.2E+03
1.4E-01
1.8E+07
1.3E+07
4.7E+06
1.7E+02
2.7E-01
potassium
2.0E+03
1.4E-01
3.1E+07
2.2E+07
8.1E+06
2.9E+02
5.5E-05
selenium
0.0E+00
5.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
1.1E+00
silicon
2.7E+01
1.4E-01
4.1E+05
3.0E+05
1.1E+05
3.9E+00
2.0E-01
silver
0.0E+00
8.3E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
sodium
2.1E+03
1.4E-01
3.2E+07
2.3E+07
8.3E+06
3.0E+02
0.0E+00
strontium
4.3E-01
1.4E-01
6.5E+03
4.8E+03
1.7E+03
6.3E-02
1.5E-06
sulphate
4.8E+03
6.1E-02
7.3E+07
3.9E+07
3.3E+07
1.2E+03
0.0E+00
sulphur
1.6E+03
1.4E-01
2.4E+07
1.8E+07
6.3E+06
2.3E+02
1.0E-04
titanium
0.0E+00
1.4E-01
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
vanadium
0.0E+00
1.0E+03
0.0E+00
0.0E+00
0.0E+00
0.0E+00
4.7E-03
zinc
3.7E+00
6.2E+01
5.5E+04
5.5E+04
4.6E+01
1.7E-03
3.3E-01
zirconium
0.0E+00
1.4E-01
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
Abbreviations: "—"= not available; Avg = Average; Cone = Concentration; Kd = soil-water partitioning coefficient.
a See Section 4.3.1 of the main report for a description of the methods and calculations used to estimate leaching from buried carcasses to ground water and to estimate maximum
likely chemical concentrations in groundwater as drawn up the well for household uses. Original leachate concentration data are from Pratt and Fonstad (2009). Leachate
accumulated on top of 40 mil liner of pit, thus, concentrations of most chemicals increased over time as the carcasses continued to decompose. Exceptions include chemicals that
might have off-gassed through the vent pipe and some that might have precipitated out of solution or sorbed to particles over time. Additional sampling dates included Nov 23,
2005, May 25, 2006, and October 26,2006.
b As described in main report, Section 3.4, the initial fresh carcass weight = 45,359 kg. Young et al. (2001) estimated that 60% of a buried mammalian corpse degrades in the first
year; 33% of the carcass mass is released during the first two months after burial; and half of that is released in the first week. Based on those estimates, the quantity of leachate
released in the first week = 7,500 L was calculated; over the next 8-10 weeks = 15,000 L; and in the first year = 27,000 L. To estimate the total mg of chemical released over the
first week (column I), concentrations from the first sample (August 17, column B) were multiplied by 7,500 L. To estimate the total mg of chemical released over the first 8-10
weeks (column J), the average concentration over the first three sampling dates (column D) was multiplied by 15,000 L. To estimate the total mg of chemical released over first
year (column K), the average concentration over the first 12 months (column E) was multiplied by 27,000 L.
G-5
-------
Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Table G.3. Estimated Leaching and Well Water Concentration of Chemicals from Buried Carcasses During the First Year.a'b
A
B
C
D
E
F
G
Chemical
Avg Cone
First Year
(mg/L)
Kd (L/kg)
Total Released
First Year (mg)
Total Filtered Back to
Soil from Leachate
First Year (mg)
Total Reaching
Groundwater
(mg)
Intercepted by
0.2 m Well Per
Day, First Year
(mg/d)
Avg Cone In
Drinking
Water, First
Year (mg/L)
1136 L/d
aluminum
6.7E-01
1.5E+03
1.8E+04
1.1E+04
7.1E+03
4.2E-02
3.7E-05
ammonium
0.0E+00
1.4E-01
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
barium
3.8E+01
4.1E+01
1.0E+06
6.2E+05
4.0E+05
2.4E+00
2.1E-03
beryllium
2.5E+03
7.9E+02
6.7E+07
4.1E+07
2.6E+07
1.6E+02
1.4E-01
bicarbonate
0.0E+00
1.0E-02
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
boron
4.2E-03
1.4E-01
1.1E+02
1.1E+02
2.3E-01
1.4E-06
1.2E-09
cadmium
7.8E-01
7.5E+01
2.1E+04
2.1E+04
4.5E+00
2.7E-05
2.4E-08
calcium
9.2E+03
1.4E-01
2.5E+08
0.0E+00
2.5E+08
1.5E+03
1.3E+00
chloride
5.6E+04
1.4E-01
1.5E+09
0.0E+00
1.5E+09
9.0E+03
8.0E+00
chromium
3.3E+01
1.9E+01
8.8E+05
8.8E+05
1.3E+03
7.5E-03
6.6E-06
cobalt
0.0E+00
4.5E+01
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
copper
1.9E+01
4.3E+02
5.1E+05
3.1E+05
2.0E+05
1.2E+00
1.1E-03
inorganic C
2.7E-01
—
7.3E+03
7.3E+03
1.0E+01
6.2E-05
5.5E-08
organic C
0.0E+00
—
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
iron
1.8E-01
6.5E+01
4.9E+03
3.0E+03
1.9E+03
1.2E-02
1.0E-05
lead
6.5E-02
9.0E+02
1.8E+03
1.8E+03
2.5E+00
1.5E-05
1.3E-08
magnesium
5.9E+00
1.4E-01
1.6E+05
9.6E+04
6.2E+04
3.7E-01
3.3E-04
manganese
1.8E+04
6.5E+01
4.9E+08
0.0E+00
4.9E+08
3.0E+03
2.6E+00
mercury
1.2E+03
2.0E-01
3.2E+07
1.9E+07
1.2E+07
7.5E+01
6.6E-02
molybdenum
2.1E+03
1.4E-01
5.6E+07
3.4E+07
2.2E+07
1.3E+02
1.2E-01
nickel
0.0E+00
6.5E+01
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
nitrate/nitrite
2.4E+01
1.4E-01
6.5E+05
3.9E+05
2.5E+05
1.5E+00
1.3E-03
total N
0.0E+00
—
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
phosphorus
2.0E+03
1.4E-01
5.4E+07
3.3E+07
2.1E+07
1.3E+02
1.1E-01
potassium
2.9E-01
1.4E-01
7.9E+03
4.8E+03
3.1E+03
1.9E-02
1.6E-05
selenium
5.0E+03
5.0E+00
1.4E+08
5.4E+07
8.2E+07
4.9E+02
4.3E-01
G-6
-------
Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
A
B
C
D
E
F
G
Chemical
Avg Cone
First Year
(mg/L)
Kd (L/kg)
Total Released
First Year (mg)
Total Filtered Back to
Soil from Leachate
First Year (mg)
Total Reaching
Groundwater
(mg)
Intercepted by
0.2 m Well Per
Day, First Year
(mg/d)
Avg Cone In
Drinking
Water, First
Year (mg/L)
1136 L/d
silicon
1.7E+03
1.4E-01
4.5E+07
2.7E+07
1.8E+07
1.1E+02
9.4E-02
silver
8.3E-03
8.3E+00
2.3E+02
1.4E+02
8.8E+01
5.3E-04
4.7E-07
sodium
0.0E+00
1.4E-01
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
strontium
2.6E+00
1.4E-01
7.1E+04
7.1E+04
1.1E+02
6.4E-04
5.6E-07
sulphate
8.3E-03
6.1E-02
2.3E+02
1.4E+02
8.8E+01
5.3E-04
4.7E-07
sulphur
6.7E-01
1.4E-01
1.8E+04
1.1E+04
7.1E+03
4.2E-02
3.7E-05
titanium
0.0E+00
1.4E-01
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
vanadium
3.8E+01
1.0E+03
1.0E+06
6.2E+05
4.0E+05
2.4E+00
2.1E-03
zinc
2.5E+03
6.2E+01
6.7E+07
4.1E+07
2.6E+07
1.6E+02
1.4E-01
zirconium
0.0E+00
1.4E-01
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
Abbreviations: "—"= not available; Avg = Average; Cone = Concentration; Kd = soil-water partitioning coefficient.
a See Section 4.3.1 of the main report for a description of the methods and calculations used to estimate leaching from buried carcasses to ground water and to estimate maximum
likely chemical concentrations in groundwater as drawn up the well for household uses. Original leachate concentration data are from Pratt and Fonstad (2009). Leachate
accumulated on top of 40 mil liner of pit, thus, concentrations of most chemicals increased over time as the carcasses continued to decompose. Exceptions include chemicals that
might have off-gassed through the vent pipe and some that might have precipitated out of solution or sorbed to particles over time. Additional sampling dates included Nov 23,
2005, May 25, 2006, and October 26,2006.
b As described in main report, Section 3.4, the initial fresh carcass weight = 45,359 kg. Young et al. (2001) estimated that 60% of a buried mammalian corpse degrades in the first
year; 33% of the carcass mass is released during the first two months after burial; and half of that is released in the first week. Based on those estimates, the quantity of leachate
released in the first week = 7,500 L was calculated; over the next 8-10 weeks = 15,000 L; and in the first year = 27,000 L. To estimate the total mg of chemical released over the
first week (column I), concentrations from the first sample (August 17, column B) were multiplied by 7,500 L. To estimate the total mg of chemical released over the first 8-10
weeks (column J), the average concentration over the first three sampling dates (column D) was multiplied by 15,000 L. To estimate the total mg of chemical released over first
year (column K), the average concentration over the first 12 months (column E) was multiplied by 27,000 L.
G-7
-------
Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Table G.4. Estimated Leaching and Well Water Concentration of Chemicals from Carcass Storage During the First Two
Days.ab
A
B
C
D
E
F
G
Chemical
Avg Cone
First Week
(mg/L)
Kd (L/kg)
Total Released,
Two Days (mg)
Total Filtered Back to
Soil from Leachate,
Two Days (mg)
Total Reaching
Groundwater
(mg)
Intercepted by
0.2 m Well Per
Day, Two Days
(mg/d)
Avg Cone In
Drinking
Water, Two
Days (mg/L)
1136 L/d
aluminum
1.7E+00
1.5E+03
3.6E+03
3.6E+03
2.2E-01
1.1E-03
2.7E-09
ammonium
5.2E+03
1.4E-01
1.1E+07
6.8E+06
4.4E+06
2.2E+04
5.2E-02
barium
3.0E-01
4.1E+01
6.4E+02
6.4E+02
1.4E+00
7.2E-03
1.7E-08
beryllium
0.0E+00
7.9E+02
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
bicarbonate
3.5E+04
1.0E-02
7.5E+07
7.3E+06
6.8E+07
3.4E+05
8.1E-01
boron
0.0E+00
1.4E-01
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
cadmium
0.0E+00
7.5E+01
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
calcium
6.0E+01
1.4E-01
1.3E+05
7.8E+04
5.0E+04
2.5E+02
6.0E-04
chloride
2.6E+03
1.4E-01
5.6E+06
3.4E+06
2.2E+06
1.1E+04
2.6E-02
chromium
0.0E+00
1.9E+01
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
cobalt
1.0E-01
4.5E+01
2.1E+02
2.1E+02
4.4E-01
2.2E-03
5.3E-09
copper
6.0E-01
4.3E+02
1.3E+03
1.3E+03
2.8E-01
1.4E-03
3.3E-09
inorganic C
6.9E+03
—
1.5E+07
0.0E+00
1.5E+07
7.3E+04
1.8E-01
organic C
4.3E+04
—
9.2E+07
0.0E+00
9.2E+07
4.6E+05
1.1E+00
iron
1.1E+02
6.5E+01
2.4E+05
2.4E+05
3.3E+02
1.7E+00
4.0E-06
lead
0.0E+00
9.0E+02
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
magnesium
3.0E+01
1.4E-01
6.4E+04
3.9E+04
2.5E+04
1.3E+02
3.0E-04
manganese
5.0E-01
6.5E+01
1.1E+03
1.1E+03
1.5E+00
7.5E-03
1.8E-08
mercury
0.0E+00
2.0E-01
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
molybdenum
1.8E+00
1.4E-01
3.9E+03
2.3E+03
1.5E+03
7.5E+00
1.8E-05
nickel
4.0E-01
6.5E+01
8.6E+02
8.5E+02
1.2E+00
6.0E-03
1.5E-08
nitrate/nitrite
2.3E+01
1.4E-01
4.9E+04
3.0E+04
1.9E+04
9.6E+01
2.3E-04
total N
1.8E+04
—
3.9E+07
0.0E+00
3.9E+07
1.9E+05
4.7E-01
phosphorus
9.2E+02
1.4E-01
2.0E+06
1.2E+06
7.7E+05
3.8E+03
9.3E-03
potassium
1.9E+03
1.4E-01
4.1E+06
2.5E+06
1.6E+06
7.9E+03
1.9E-02
G-8
-------
Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
A
B
C
D
E
F
G
Chemical
Avg Cone
First Week
(mg/L)
Kd (L/kg)
Total Released,
Two Days (mg)
Total Filtered Back to
Soil from Leachate,
Two Days (mg)
Total Reaching
Groundwater
(mg)
Intercepted by
0.2 m Well Per
Day, Two Days
(mg/d)
Avg Cone In
Drinking
Water, Two
Days (mg/L)
1136 L/d
selenium
0.0E+00
5.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
silicon
2.9E+01
1.4E-01
6.2E+04
3.8E+04
2.4E+04
1.2E+02
2.9E-04
silver
0.0E+00
8.3E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
sodium
1.6E+03
1.4E-01
3.4E+06
2.1E+06
1.3E+06
6.7E+03
1.6E-02
strontium
7.0E-01
1.4E-01
1.5E+03
9.1E+02
5.9E+02
2.9E+00
7.0E-06
sulphate
3.7E+03
6.1E-02
7.9E+06
3.2E+06
4.8E+06
2.4E+04
5.7E-02
sulphur
1.2E+03
1.4E-01
2.6E+06
1.6E+06
1.0E+06
5.0E+03
1.2E-02
titanium
2.0E-01
1.4E-01
4.3E+02
2.6E+02
1.7E+02
8.3E-01
2.0E-06
vanadium
0.0E+00
1.0E+03
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
zinc
3.5E+00
6.2E+01
7.5E+03
7.5E+03
1.1E+01
5.5E-02
1.3E-07
zirconium
2.0E-01
1.4E-01
4.3E+02
2.6E+02
1.7E+02
8.3E-01
2.0E-06
Abbreviations: "—" = not available; Avg = Average; Cone = Concentration; Kd = soil-water partitioning coefficient.
a See Section 4.3.1 of the main report for a description of the methods and calculations used to estimate leaching from buried carcasses to ground water and to estimate maximum
likely chemical concentrations in groundwater as drawn up the well for household uses. Original leachate concentration data are from Pratt and Fonstad (2009). Leachate
accumulated on top of 40 mil liner of pit, thus, concentrations of most chemicals increased over time as the carcasses continued to decompose. Exceptions include chemicals that
might have off-gassed through the vent pipe and some that might have precipitated out of solution or sorbed to particles over time. Additional sampling dates included Nov 23,
2005, May 25, 2006, and October 26,2006.
b As described in main report, Section 3.4, the initial fresh carcass weight = 45,359 kg. Young et al. (2001) estimated that 60% of a buried mammalian corpse degrades in the first
year; 33% of the carcass mass is released during the first two months after burial; and half of that is released in the first week. Based on those estimates, the quantity of leachate
released in the first week = 7,500 L was calculated; over the next 8-10 weeks = 15,000 L; and in the first year = 27,000 L. To estimate the total mg of chemical released over the
first week (column I), concentrations from the first sample (August 17, column B) were multiplied by 7,500 L. To estimate the total mg of chemical released over the first 8-10
weeks (column J), the average concentration over the first three sampling dates (column D) was multiplied by 15,000 L. To estimate the total mg of chemical released over first
year (column K), the average concentration over the first 12 months (column E) was multiplied by 27,000 L.
G-9
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Table G.5. Estimated Leaching and Well Water Concentration of Chemicals from a Windrow During the First Year.a'b
A
B
C
D
E
F
G
H
Chemical
Avg Cone
First Year
(mg/L)
Kd (L/kg)
Total
Released
from
Carcasses
(mg/yr)
Total
Released
from
Windrow
(mg/yr)
Total Filtered
Back to Soil
from
Leachate
First Year
(mg/yr)
Total
Reaching
Groundwater
(mg/yr)
Intercepted
by 0.2 m
Well, First
Year (mg/yr)
Avg Cone In
Drinking
Water, First
Year (mg/L)
1136 L/d
aluminum
6.7E-01
1.5E+03
1.7E+04
8.4E+02
8.4E+02
5.2E-02
1.7E-04
4.1E-10
ammonium
0.0E+00
1.4E-01
3.0E+08
1.5E+07
9.0E+06
5.8E+06
1.9E+04
4.6E-02
barium
3.8E+01
4.1E+01
4.7E+03
2.4E+02
2.4E+02
5.3E-01
1.8E-03
4.2E-09
beryllium
2.5E+03
7.9E+02
na
na
na
na
na
na
bicarbonate
0.0E+00
1.0E-02
1.3E+09
6.4E+07
6.2E+06
5.8E+07
1.9E+05
4.6E-01
boron
4.2E-03
1.4E-01
1.8E+04
9.0E+02
5.5E+02
3.5E+02
1.2E+00
2.8E-06
cadmium
7.8E-01
7.5E+01
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
calcium
9.2E+03
1.4E-01
1.0E+06
5.1E+04
3.1E+04
2.0E+04
6.5E+01
1.6E-04
chloride
5.6E+04
1.4E-01
6.7E+07
3.4E+06
2.0E+06
1.3E+06
4.3E+03
1.0E-02
chromium
3.3E+01
1.9E+01
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
cobalt
0.0E+00
4.5E+01
1.1E+02
5.6E+00
5.6E+00
1.2E-02
3.8E-05
9.1E-11
copper
1.9E+01
4.3E+02
2.1E+04
1.0E+03
1.0E+03
2.3E-01
7.4E-04
1.8E-09
inorganic C
2.7E-01
—
2.5E+08
1.2E+07
0.0E+00
1.2E+07
4.1E+04
9.9E-02
organic C
0.0E+00
—
1.5E+09
7.5E+07
0.0E+00
7.5E+07
2.5E+05
6.0E-01
iron
1.8E-01
6.5E+01
8.8E+05
4.4E+04
4.4E+04
6.3E+01
2.1E-01
4.9E-07
lead
6.5E-02
9.0E+02
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
magnesium
5.9E+00
1.4E-01
5.1E+05
2.5E+04
1.5E+04
1.0E+04
3.3E+01
7.9E-05
manganese
1.8E+04
6.5E+01
7.3E+03
3.6E+02
3.6E+02
5.2E-01
1.7E-03
4.1E-09
mercury
1.2E+03
2.0E-01
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
molybdenum
2.1E+03
1.4E-01
4.9E+03
2.4E+02
1.5E+02
9.6E+01
3.1E-01
7.6E-07
nickel
0.0E+00
6.5E+01
1.8E+03
8.8E+01
8.8E+01
1.3E-01
4.1E-04
9.9E-10
nitrate/nitrite
2.4E+01
1.4E-01
1.6E+05
7.9E+03
4.8E+03
3.1E+03
1.0E+01
2.5E-05
total N
0.0E+00
—
4.9E+08
2.5E+07
0.0E+00
2.5E+07
8.1E+04
2.0E-01
phosphorus
2.0E+03
1.4E-01
3.2E+07
1.6E+06
9.6E+05
6.2E+05
2.0E+03
4.9E-03
potassium
2.9E-01
1.4E-01
5.6E+07
2.8E+06
1.7E+06
1.1E+06
3.6E+03
8.7E-03
G-10
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
A
B
C
D
E
F
G
H
Chemical
Avg Cone
First Year
(mg/L)
Kd (L/kg)
Total
Released
from
Carcasses
(mg/yr)
Total
Released
from
Windrow
(mg/yr)
Total Filtered
Back to Soil
from
Leachate
First Year
(mg/yr)
Total
Reaching
Groundwater
(mg/yr)
Intercepted
by 0.2 m
Well, First
Year (mg/yr)
Avg Cone In
Drinking
Water, First
Year (mg/L)
1136 L/d
selenium
5.0E+03
5.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
silicon
1.7E+03
1.4E-01
6.5E+05
3.2E+04
2.0E+04
1.3E+04
4.2E+01
1.0E-04
silver
8.3E-03
8.3E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
sodium
0.0E+00
1.4E-01
5.4E+07
2.7E+06
1.7E+06
1.1E+06
3.5E+03
8.5E-03
strontium
2.6E+00
1.4E-01
7.9E+03
4.0E+02
2.4E+02
1.6E+02
5.1E-01
1.2E-06
sulphate
8.3E-03
6.1E-02
1.4E+08
6.8E+06
2.7E+06
4.1E+06
1.3E+04
3.2E-02
sulphur
6.7E-01
1.4E-01
4.5E+07
2.3E+06
1.4E+06
8.9E+05
2.9E+03
7.0E-03
titanium
0.0E+00
1.4E-01
2.3E+02
1.1E+01
6.8E+00
4.4E+00
1.4E-02
3.5E-08
vanadium
3.8E+01
1.0E+03
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
zinc
2.5E+03
6.2E+01
7.1E+04
3.6E+03
3.6E+03
5.3E+00
1.7E-02
4.2E-08
zirconium
0.0E+00
1.4E-01
2.3E+02
1.1E+01
6.8E+00
4.4E+00
1.4E-02
3.5E-08
Abbreviations: "—" = not available; Avg = Average; Cone = Concentration; Kd = soil-water partitioning coefficient; na = not analyzed.
a See Section 4.3.1 of the main report for a description of the methods and calculations used to estimate leaching from buried carcasses to ground water and to estimate maximum
likely chemical concentrations in groundwater as drawn up the well for household uses. Original leachate concentration data are from Pratt and Fonstad (2009). Leachate
accumulated on top of 40 mil liner of pit, thus, concentrations of most chemicals increased over time as the carcasses continued to decompose. Exceptions include chemicals that
might have off-gassed through the vent pipe and some that might have precipitated out of solution or sorbed to particles over time. Additional sampling dates included Nov 23,
2005, May 25, 2006, and October 26,2006.
b As described in main report, Section 3.4, the initial fresh carcass weight = 45,359 kg. Young et al. (2001) estimated that 60% of a buried mammalian corpse degrades in the first
year; 33% of the carcass mass is released during the first two months after burial; and half of that is released in the first week. Based on those estimates, the quantity of leachate
released in the first week = 7,500 L was calculated; over the next 8-10 weeks = 15,000 L; and in the first year = 27,000 L. To estimate the total mg of chemical released over the
first week (column I), concentrations from the first sample (August 17, column B) were multiplied by 7,500 L. To estimate the total mg of chemical released over the first 8-10
weeks (column J), the average concentration over the first three sampling dates (column D) was multiplied by 15,000 L. To estimate the total mg of chemical released over first
year (column K), the average concentration over the first 12 months (column E) was multiplied by 27,000 L.
G-ll
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Table G.6. Documentation of Columns A through H in Tables G.l - G.5.
Column
Description of Column Data or Calculation
Origin of Values or Equation Parameters
A
Average concentration in burial leachate for time period
indicated.
Data presented in Pratt and Fondstad (2009).
B
Chemical-specific solid-liquid partition coefficient. Used
to estimate equilibrium distribution of chemical between
soil & leachate.
HHRAP companion database and other sources.
C
Total amount of chemical (mg) leached from carcass in
time period indicated. See footnote b to the tables for
information about the leachate volumes.
(Col. A) x 7,500 liters fluid leached in first week,
(Col. A) x 15,000 liters fluid leached in first two months, and
(Col. A) x 27,000 liters fluid leached in first year.
D
Windrow scenario only. Total chemical released from
windrow to ground below. Percentage assumption based
on Glanville et al. (2006) and Donaldson et al. (2012).
(Col. C) x 5% [the percentage of leachate that is not absorbed by woodchips or other
carbon bulking material].
E
Amount of chemical (mg) absorbed to soil as the leachate
passes through vadose zone soil.
[(Col. B ) x [dry weight of soil saturated by leachate, in kg] x (Col. C)] / [volume of
leachate in L) + (Col. B) x dry weight of soil saturated by leachate, in kg)].
For the windrow scenario only, substitute Col. D for Col. C. See section 4.3.1 of the
main report a discussion of this equation.
Dry weights of soil saturated by leachate:
• burial scenario - 291,600 kg,
• storage pile scenario - 23,112 kg, and
• windrow scenario - 14,580 kg.
These are estimated assuming a water-filled soil porosity of 0.2 (unitless) and a solids
particle density of 2.7 g/cmA3, both HHRAP defaults.
F
Amount of chemical (mg) that reaches the groundwater
aquifer.
(Col. C. - Col. E).
For the windrow scenario only, substitute Col. D for Col. C.
G
Amount of chemical intercepted by the drinking water
well per day.
(Col. F/[number of days during period indicated] x (fraction plume intercepted)].
See main report. Section 4.3.5 for further discussion of methods for well water
concentrations. Fraction of plume intercepted (Section 4.3.5):
• burial scenario - 0.0022,
• storage pile scenario - 0.0050, and
• windrow scenario - 0.0033.
H
Average chemical concentration (mg/L) in drinking water.
[(Col. G)/1,136L/d).
Abbreviations: A = raised to the power of; Col. = column; d = days; HHRAP = Human Health Risk Assessment Protocol for Hazardous Waste Combustion Facilities', mo = month;
wk = w.
G-12
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
latlon for Chemical Leaching
from Combustion Ash
Section 4.3.2 of the main report describes the data and calculations used to estimate chemical
leaching of from ash to groundwater for the on-site open burning and air-curtain burning options.
Table H. 1 through Table H.8 documents the derivation of data and calculations for buried ash.
Documentation in Table H.8 provides further details of these estimation methods, including data
and assumptions about the amount of ash produced by each option (Table H. 1), the area of ash
disposal (Table H.2), the precipitation that infiltrates the ash and becomes leachate and soil
properties used in partitioning calculations (Table H.3), concentrations of chemicals in ash from
open burning (Table H.4) and air-curtain burning (Table H.5), formulas used to estimate leaching
(Table H.86 and Table H.7), and a key to the columns in Table H.6 and Table H.7 (Table H.8).
References
Air Burners, Inc. (2012). Firebox Specifications, S-327. Palm City, FL: Air Burners, Inc.
Retrieved June 7, 2015 from http://www.airburners.com/DATA-F1LES Print/ab-
s327 Specs PRNT.pdf.
Butalia T, Wolfe W, Dick W, etal. (2015). Coal Combustion Products. Ohio State University
Fact Sheet. Food, Agricultural and Biological Engineering. AEX-330-99. Columbus, OH: Ohio
State University.
NABCC (National Agricultural Biosecurity Center Consortium) (2004). Carcass Disposal: A
Comprehensive Review. Report prepared by the NABCC, Carcass Disposal Working Group, For
the USD A Animal & Plant Health Inspection Service, Per Cooperative Agreement 02-1001-
0355-CA. Retrieved July 5, 2014 from https://krex.k-state.edu/dspace/handle/20Q7/662.
Narodoslawsky M, Obernberger I (1996). From waste to raw material - the route from biomass
to wood ash for cadmium and other heavy metals. Journal of Hazardous Materials 50: 157-168.
H-l
-------
Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
NRC (National Research Council) (2000). Waste Incineration & Public Health. Commission on
Life Sciences, Board on Environmental Studies and Toxicology. Washington, DC: National
Academy Press.
Pitman RM (2006). Wood ash use in forestry - a review of the environmental impacts. Forestry
79(5): 563-588. Retrieved August 18, 2015 from
http ://forestry. oxfordi ournal s. org/ content/79/5/5 63. full.
USD A (U.S. Department of Agriculture) (2005). Operational Guidelines: Disposal. National
Animal Health Emergency Management System Guidelines. Riverdale, MD: Animal and Plant
Health Inspection Service, Veterinary Services. Retrieved July 23, 2014 from
http://www.aphis.usda.gov/emergencv response/tools/on-
site/htdocs/images/nahems disposal.pdf.
Watkiss P, Smith A (2001). CBA [Cost Benefit Analysis] of Foot and Mouth Disease Control
Strategies: Environmental Impacts. London: Harwell, Didcot, Oxen. AEA Technology
Environment, Report no. ED51178001.
H-2
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Table H.l. Quantities of Fuels and Ash for On-site Combustion-based Carcass Management Options.
Management
Combusted Material
Fuel Mass Per 100 cattle
(each weighing 1,000 lbs)
Percent
Ash
Total Ash
Remaining
Total Ash
Remaining
Option
kg
lb
U.S. Tons
(tons)
(kg)
Combustion Fuels
Open Burning
300 hay bales (3 per carcass3 x 20 kg per
baleb)
6,000
13,228
7
1.00%d
0.07
60
300 heavy timbers, 8 ft3 each (3 per carcass3
x 500 kg/m3 per railroad tieb )
33,980
74,913
37
1.00%d
0.37
340
50 lbs kindling [per carcass] x 100 cows =
5,000 lbs
2,268
5,000
3
1.00%d
0.03
23
10,000 lbs coal [100 lbs/carcass3]
4,536
10,000
5
2.00%e
0.10
91
100 gal gasoline [1 gallon per animal3]
286
630
0
0.00%
0.00
-
Total
47,070
103,771
52
--
0.57
513
Air-curtain
Burning
Wood (4:1 wood to carcass ratio. 50 U.S.
tons carcass requires 200 tons wood)
181,437
399,999
200
0.27%f
0.55
498
200 gal diesel inside unit (NABCC 2004)
642
1,415
1
-0.00%
0.00
-
168 gal diesel blower fuel (3.5 gal/hr° x 48
hr burn)
539
1,189
1
-0.00%
0.00
-
Total
182,172
401,620
201
--
0.55
498
Ash from Carcass Combustion
Open Burning
100 carcasses; 1000 lb each; 50 tons total
45,359
100,000
50
6.00%g
3.00
2,722
Air-curtain
100 carcasses; 1000 lb each; 50 tons total
45,359
100,000
50
6.00%g
3.00
2,722
Total Ash from Carcasses and fuels
Open Burning
3.6
3.235
Air-curtain Burning
3.5
3,220
Abbreviations: ft = feet; gal = gallons; hr = hours; lbs = pounds.
a USDA (2005)
b Watkiss and Smith (2001)
c Air Burners, Inc. (2012)
d Pitman (2006)
e Butalia et al. (2015)
f Narodoslawsky and Obemberger (1996)
g NRC 2000
Table H.2. Ash Disposal Areas.
Management Option Area Basis Ash Disposal Area
H-3
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
ft2
m2
Open Burning
Cover ash in place. Disposal area is the same as the pyre area: 8 ft x 300 fta
2,400
223
Air-curtain Burning
Bury ash in a pit assumed to have the same dimensions as the air-curtain burner: 11,40m x 3,6m b
441
41
Abbreviations: ft = feet; ft2 = square feet.
a USDA (2005).
b Air Burners, Inc. (2012).
Table H.3. Precipitation and Soil Assumptions for Leaching Calculations.
Parameter No.
Meteorological or Soil Parameter
Estimate
Basis of Estimate
PI
Total annual precipitation
96.84 cm/yr
Meteorological data (see main report. Section
2.1.1)
P2
Number of rain events per year
168 events/yr
Meteorological data (see main report. Section
2.1.1)
P3
Total precipitation hours
435 lir/yr
Meteorological data (see main report. Section
2.1.1)
P4
Precipitation per event
0.5764 cm/event
Calculated: P1/P2
P5
Precipitation per rain hour
0.2226 cm/rain hr
Calculated: P1/P3
P6
Average hours per event
2.6 hr
Calculated: P3/P2
P7
Water volume per nf of surface area per event
5764 cm3 (5.8 L)
Calculated: P4 * 100 cm * 100 cm
P8
Total volume of water per nf per year
968.4 L
Calculated: P7*P2
P9
Water-filled soil porosity
0.2 dimensionless
HHRAP default (USEPA 2005)
P10
Soil particle density
2.7 g/cnf (2.7 kg/L)
HHRAP default (USEPA 2005)
Pll
Volume of soil per nf area saturated per rain event
29 L (0.029 nf)
Calculated: P7/P9
P12
Dry weight of saturated soil
62 kg
Calculated: Pll * (1 -P9) * P10
P13
Depth of unsaturated soil zone
1 m
Assumed
P14
Depth of soil saturated per rain event
0.029 m
Calculated: PI 1/1 nf
P15
Number of soil layers in unsaturated zone
35
Calculated: P13/P14
Abbreviations: HHRAP = Human Health Risk Assessment Protocol for Hazardous Waste Combustion Facilities', hr = hours.
H-4
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Table H.4. Estimated Chemical Concentrations in Ash from Open Burning.
Chemical Cone. In Ash (jig/kg)
C
"hemical Mass in Ash (mg)
Chem.
Cone. In
Chem.
Chemical (PAH number of rings)
Ash from
Carcasses
Ash from
Wood
Fuels
Ash from
Coal
Ash from
Carcasses
Ash from
Wood
Fuels
Ash from
Coal
Total
Pyre
Ash
(mg/kg)
Cone. In
Pyre Ash
(Mg/kg)
A
B
C
D
E
F
G
H
I
Napthalene (2)
1.2E+02
3E+03
2.3E+02
3.3E+02
1.2E+03
2.1E+01
1.5E+03
4.7E-01
4.7E+02
Acenapthylene (3)
5.0E+00
1E+02
nd
1.4E+01
4.8E+01
na
6.2E+01
1.9E-02
1.9E+01
Phenanthrene (3)
4.6E+01
1E+03
3.1E+02
1.3E+02
4.5E+02
2.8E+01
6.0E+02
1.9E-01
1.9E+02
Fluorene (3)
1.5E+01
3E+02
2.8E+02
4.1E+01
1.5E+02
2.5E+01
2.1E+02
6.5E-02
6.5E+01
Acenaphthene (3)
1.0E+01
2E+02
1.9E+02
2.7E+01
9.7E+01
1.7E+01
1.4E+02
4.4E-02
4.4E+01
Anthracene (3)
3.3E+01
8E+02
nd
8.9E+01
3.2E+02
na
4.1E+02
1.3E-01
1.3E+02
Pyrene (4)
2.5E+01
6E+02
2.6E+02
6.8E+01
2.4E+02
2.3E+01
3.3E+02
1.0E-01
1.0E+02
Chrysene (4)
3.2E+01
7E+02
2.1E+02
8.7E+01
3.1E+02
1.9E+01
4.2E+02
1.3E-01
1.3E+02
Fluoranthene (4)
2.5E+01
6E+02
2.9E+02
6.8E+01
2.4E+02
2.6E+01
3.4E+02
1.0E-01
1.0E+02
Benzo[a]anthracene (4)
1.0E+01
2E+02
2.9E+02
2.7E+01
9.7E+01
2.7E+01
1.5E+02
4.7E-02
4.7E+01
Benzo[a]pyrene (5)
3.5E+01
8E+02
8.7E+02
9.5E+01
3.4E+02
7.9E+01
5.1E+02
1.6E-01
1.6E+02
Benzo[e]pyrene (5)
1.5E+01
3E+02
na
4.1E+01
1.5E+02
na
1.9E+02
5.8E-02
5.8E+01
Benzo[b]fluoranthene (5)
1.5E+01
3E+02
3.6E+02
4.1E+01
1.5E+02
3.2E+01
2.2E+02
6.8E-02
6.8E+01
Benzo[k]fluoranthene (5)
1.0E+01
2E+02
4.2E+02
2.7E+01
9.7E+01
3.8E+01
1.6E+02
5.0E-02
5.0E+01
Cyclopenta[c,d]pyrene (5)
2.0E+01
5E+02
na
5.4E+01
1.9E+02
na
2.5E+02
7.7E-02
7.7E+01
Perylene (5)
2.5E+01
6E+02
na
6.8E+01
2.4E+02
na
3.1E+02
9.6E-02
9.6E+01
Dibenz[a,h]anthracene (6)
4.1E+01
9E+02
2.5E+02
1.1E+02
4.0E+02
2.2E+01
5.3E+02
1.6E-01
1.6E+02
Indeno[l,2,3-cd] pyrene (6)
3.8E+01
9E+02
2.6E+02
1.0E+02
3.7E+02
2.4E+01
5.0E+02
1.5E-01
1.5E+02
Benzo[g,h,i]perylene (6)
2.2E+01
5E+02
1.1E+02
6.0E+01
2.1E+02
9.5E+00
2.8E+02
8.7E-02
8.7E+01
Benzo[b]clirysene (6)
1.9E+01
4E+02
na
5.2E+01
1.8E+02
na
2.4E+02
7.3E-02
7.3E+01
Coronene (7)
1.7E+02
4E+03
na
4.6E+02
1.6E+03
na
2.1E+03
6.5E-01
6.5E+02
Total PAHs
2.9E+00
2.9E+03
OctaCDD, 1,2,3,4,6,7,8,9-
na
3.0E-02
na
na
1.3E-02
na
1.3E-02
3.9E-06
3.9E-03
OctaCDF, 1,2,3,4,6,7,8,9-
na
1.9E-03
na
na
8.0E-04
na
8.0E-04
2.5E-07
2.5E-04
HeptaCDD, 1,2,3,4,6,7,8-
na
9.0E-03
na
na
3.8E-03
na
3.8E-03
1.2E-06
1.2E-03
HeptaCDF, 1,2,3,4,6,7,8-
na
6.0E-03
na
na
2.5E-03
na
2.5E-03
7.8E-07
7.8E-04
HeptaCDF, 1,2,3,4,7,8,9-
na
1.8E-03
na
na
7.6E-04
na
7.6E-04
2.4E-07
2.4E-04
HexaCDD, 1,2,3,4,7,8-
na
1.7E-03
na
na
7.2E-04
na
7.2E-04
2.2E-07
2.2E-04
H-5
-------
Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Chemical Cone. In Ash (jig/kg)
C
"hemical Mass in Ash (mg)
Chem.
Cone. In
Chem.
Chemical (PAH number of rings)
Ash from
Carcasses
Ash from
Wood
Fuels
Ash from
Coal
Ash from
Carcasses
Ash from
Wood
Fuels
Ash from
Coal
Total
Pyre
Ash
(mg/kg)
Cone. In
Pyre Ash
(Mg/kg)
A
B
C
D
E
F
G
H
I
HexaCDF, 1,2,3,4,7,8-
na
1.8E-03
na
na
7.6E-04
na
7.6E-04
2.4E-07
2.4E-04
HexaCDD, 1,2,3,6,7,8-
na
1.1E-03
na
na
4.6E-04
na
4.6E-04
1.4E-07
1.4E-04
HexaCDF, 1,2,3,6,7,8-
na
7.0E-03
na
na
3.0E-03
na
3.0E-03
9.1E-07
9.1E-04
HexaCDD, 1,2,3,7,8,9 -
na
1.7E-03
na
na
7.2E-04
na
7.2E-04
2.2E-07
2.2E-04
HexaCDF, 1,2,3,7,8,9-
na
1.0E-03
na
na
4.2E-04
na
4.2E-04
1.3E-07
1.3E-04
PentaCDD, 1,2,3,7,8-
na
1.7E-03
na
na
7.2E-04
na
7.2E-04
2.2E-07
2.2E-04
PentaCDF, 1,2,3,7,8-
na
4.0E-03
na
na
1.7E-03
na
1.7E-03
5.2E-07
5.2E-04
HexaCDF, 2,3,4,6,7,8-
na
1.3E-03
na
na
5.5E-04
na
5.5E-04
1.7E-07
1.7E-04
PentaCDF, 2,3,4,7,8-
na
3.5E-03
na
na
1.5E-03
na
1.5E-03
4.6E-07
4.6E-04
TetraCDD, 2,3,7,8-
na
8.0E-04
na
na
3.4E-04
na
3.4E-04
1.0E-07
1.0E-04
TetraCDF, 2,3,7,8-
na
4.0E-03
na
na
1.7E-03
na
1.7E-03
5.2E-07
5.2E-04
Total Dioxins/furans
1.0E-05
1.0E-02
Arsenic
nd
3.0E+03
1.4E+02
na
1.3E+03
1.3E+01
1.3E+03
3.9E-01
3.9E+02
Cadmium
3.1E+02
1.2E+03
0.0E+00
8.4E+02
4.9E+02
0.0E+00
1.3E+03
4.1E-01
4.1E+02
Cliromium, total
5.5E+03
1.9E+05
5.2E+04
1.5E+04
7.9E+04
4.7E+03
9.9E+04
3.0E+01
3.0E+04
Copper
2.3E+04
1.5E+05
4.8E+04
6.3E+04
6.2E+04
4.3E+03
1.3E+05
4.0E+01
4.0E+04
Iron
1.2E+04
1.2E+07
4.9E+07
3.2E+04
5.0E+06
4.5E+06
9.5E+06
2.9E+03
2.9E+06
Lead
1.3E+03
7.7E+03
1.7E+04
3.6E+03
3.3E+03
1.6E+03
8.5E+03
2.6E+00
2.6E+03
Manganese
2.3E+03
1.2E+07
2.8E+05
6.4E+03
5.2E+06
2.5E+04
5.2E+06
1.6E+03
1.6E+06
Nickel
8.1E+03
2.7E+04
4.2E+04
2.2E+04
1.1E+04
3.8E+03
3.7E+04
1.2E+01
1.2E+04
Zinc
3.2E+03
4.9E+05
5.7E+04
8.8E+03
2.1E+05
5.2E+03
2.2E+05
6.8E+01
6.8E+04
Abbreviations: na = not applicable; nd = no data; PAH = polycyclic aromatic hydrocarbon.
H-6
-------
Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Table H.5. Estimated Chemical Concentrations in Ash from Air-Curtain Burning.
Chemical Cone. In Ash (jig/kg)
Total Chemical Mass in Ash (mg)
Chem.
Chem.
Chemical
(PAH number of rings)
Ash from
Carcasses
Ash from
Wood
Ash from
Coal
Ash from
Carcasses
Ash from
Wood
Ash from
Coal
Total
Cone. In
Pyre Ash
(mg/kg)
Cone. In
Pyre Ash
(Mg/kg)
A
B
C
D
E
F
G
H
I
Napthalene (2)
8.6E+01
2E+03
na
2.3E+02
9.8E+02
0.0E+00
1.2E+03
3.8E-01
3.8E+02
Acenapthylene (3)
1.9E+01
4E+02
na
5.2E+01
2.2E+02
0.0E+00
2.7E+02
8.4E-02
8.4E+01
Phenanthrene (3)
6.5E+01
1E+03
na
1.8E+02
7.4E+02
0.0E+00
9.2E+02
2.9E-01
2.9E+02
Fluorene (3)
1.2E+01
3E+02
na
3.3E+01
1.4E+02
0.0E+00
1.7E+02
5.3E-02
5.3E+01
Acenaphthene (3)
2.5E+01
6E+02
na
6.8E+01
2.9E+02
0.0E+00
3.5E+02
1.1E-01
1.1E+02
Anthracene (3)
1.5E+01
3E+02
na
4.1E+01
1.7E+02
0.0E+00
2.1E+02
6.6E-02
6.6E+01
Pyrene (4)
2.3E+01
5E+02
na
6.3E+01
2.6E+02
0.0E+00
3.3E+02
1.0E-01
1.0E+02
Chrysene (4)
1.0E+01
2E+02
na
2.7E+01
1.1E+02
0.0E+00
1.4E+02
4.4E-02
4.4E+01
Fluoranthene (4)
5.0E+01
1E+03
na
1.4E+02
5.7E+02
0.0E+00
7.1E+02
2.2E-01
2.2E+02
Benzo[a]anthracene (4)
5.0E+00
1E+02
na
1.4E+01
5.7E+01
0.0E+00
7.1E+01
2.2E-02
2.2E+01
Benzo[a]pyrene (5)
6.0E+00
1E+02
na
1.6E+01
6.9E+01
0.0E+00
8.5E+01
2.6E-02
2.6E+01
Benzo[e]pyrene (5)
5.0E+00
1E+02
na
1.4E+01
5.7E+01
0.0E+00
7.1E+01
2.2E-02
2.2E+01
Benzo[b]fluoranthene (5)
3.0E+00
7E+01
na
8.2E+00
3.4E+01
0.0E+00
4.2E+01
1.3E-02
1.3E+01
Benzo[k]fluoranthene (5)
2.3E+01
5E+02
na
6.3E+01
2.6E+02
0.0E+00
3.3E+02
1.0E-01
1.0E+02
Cyclopenta[c,d]pyrene (5)
7.0E+00
2E+02
na
1.9E+01
8.0E+01
0.0E+00
9.9E+01
3.1E-02
3.1E+01
Perylene (5)
8.0E+00
2E+02
na
2.2E+01
9.1E+01
0.0E+00
1.1E+02
3.5E-02
3.5E+01
Dibenz[a,h]anthracene (6)
3.0E+00
7E+01
na
8.2E+00
3.4E+01
0.0E+00
4.2E+01
1.3E-02
1.3E+01
Indeno[l,2,3-c,d] pyrene (6)
4.0E+00
9E+01
na
1.1E+01
4.6E+01
0.0E+00
5.7E+01
1.8E-02
1.8E+01
Benzo[g,h,i]perylene (6)
3.0E+01
7E+02
na
8.2E+01
3.4E+02
0.0E+00
4.2E+02
1.3E-01
1.3E+02
Benzo[b]clirysene (6)
1.5E+01
3E+02
na
4.1E+01
1.7E+02
0.0E+00
2.1E+02
6.6E-02
6.6E+01
Coronene (7)
6.0E+01
1E+03
na
1.6E+02
6.9E+02
0.0E+00
8.5E+02
2.6E-01
2.6E+02
Total PAHs
2.1E+00
2.1E+3
OctaCDD, 1,2,3,4,6,7,8,9-
na
3.0E-02
na
na
1.5E-02
na
1.5E-02
4.6E-06
4.6E-03
OctaCDF, 1,2,3,4,6,7,8,9-
na
1.9E-03
na
na
9.5E-04
na
9.5E-04
2.9E-07
2.9E-04
HeptaCDD, 1,2,3,4,6,7,8-
na
9.0E-03
na
na
4.5E-03
na
4.5E-03
1.4E-06
1.4E-03
HeptaCDF, 1,2,3,4,6,7,8-
na
6.0E-03
na
na
3.0E-03
na
3.0E-03
9.3E-07
9.3E-04
HeptaCDF, 1,2,3,4,7,8,9-
na
1.8E-03
na
na
9.0E-04
na
9.0E-04
2.8E-07
2.8E-04
HexaCDD, 1,2,3,4,7,8-
na
1.7E-03
na
na
8.5E-04
na
8.5E-04
2.6E-07
2.6E-04
H-7
-------
Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Chemical Cone. In Ash (jig/kg)
Total Chemical Mass in Ash
(mg)
Chem.
Chem.
Chemical
(PAH number of rings)
Ash from
Carcasses
Ash from
Wood
Ash from
Coal
Ash from
Carcasses
Ash from
Wood
Ash from
Coal
Total
Cone. In
Pyre Ash
(mg/kg)
Cone. In
Pyre Ash
(Mg/kg)
A
B
C
D
E
F
G
H
I
HexaCDF, 1,2,3,4,7,8-
na
1.8E-03
na
na
9.0E-04
na
9.0E-04
2.8E-07
2.8E-04
HexaCDD, 1,2,3,6,7,8-
na
1.1E-03
na
na
5.5E-04
na
5.5E-04
1.7E-07
1.7E-04
HexaCDF, 1,2,3,6,7,8-
na
7.0E-03
na
na
3.5E-03
na
3.5E-03
1.1E-06
1.1E-03
HexaCDD, 1,2,3,7,8,9 -
na
1.7E-03
na
na
8.5E-04
na
8.5E-04
2.6E-07
2.6E-04
HexaCDF, 1,2,3,7,8,9-
na
1.0E-03
na
na
5.0E-04
na
5.0E-04
1.5E-07
1.5E-04
PentaCDD, 1,2,3,7,8-
na
1.7E-03
na
na
8.5E-04
na
8.5E-04
2.6E-07
2.6E-04
PentaCDF, 1,2,3,7,8-
na
4.0E-03
na
na
2.0E-03
na
2.0E-03
6.2E-07
6.2E-04
HexaCDF, 2,3,4,6,7,8-
na
1.3E-03
na
na
6.5E-04
na
6.5E-04
2.0E-07
2.0E-04
PentaCDF, 2,3,4,7,8-
na
3.5E-03
na
na
1.7E-03
na
1.7E-03
5.4E-07
5.4E-04
TetraCDD, 2,3,7,8-
na
8.0E-04
na
na
4.0E-04
na
4.0E-04
1.2E-07
1.2E-04
TetraCDF, 2,3,7,8-
na
4.0E-03
na
na
2.0E-03
na
2.0E-03
6.2E-07
6.2E-04
Total Dioxins/furans
1.2E-05
1.2E-02
Arsenic
nd
3.0E+03
na
na
1.5E+03
0.0E+00
1.5E+03
4.6E-01
4.6E+02
Cadmium
3.0E+01
1.2E+03
na
8.2E+01
5.8E+02
0.0E+00
6.6E+02
2.1E-01
2.1E+02
Cliromium, total
3.7E+03
1.9E+05
na
1.0E+04
9.3E+04
0.0E+00
1.0E+05
3.2E+01
3.2E+04
Copper
1.2E+04
1.5E+05
na
3.2E+04
7.3E+04
0.0E+00
1.1E+05
3.3E+01
3.3E+04
Iron
4.1E+05
1.2E+07
na
1.1E+06
5.9E+06
0.0E+00
7.0E+06
2.2E+03
2.2E+06
Lead
3.6E+04
7.7E+03
na
9.7E+04
3.8E+03
0.0E+00
1.0E+05
3.1E+01
3.1E+04
Manganese
8.6E+03
1.2E+07
na
2.3E+04
6.1E+06
0.0E+00
6.1E+06
1.9E+03
1.9E+06
Nickel
7.2E+03
2.7E+04
na
2.0E+04
1.4E+04
0.0E+00
3.3E+04
1.0E+01
1.0E+04
Zinc
8.9E+04
4.9E+05
na
2.4E+05
2.4E+05
0.0E+00
4.8E+05
1.5E+02
1.5E+05
Abbreviations: Chem. = Chemical; Cone. Concentration; na = not applicable; nd = no data; PAH = polycyclic aromatic hydrocarbon.
H-8
-------
Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Table H.6. Estimated Leaching of Chemicals from Ash and Partitioning with Subsurface Soil - Open Burning.3
A
B
C
D
E
F
G
H
I
J
K
Chemical
Total in
Ash
(mg)
Chem.
per area
(mg /
m2)
Kd
(L/kg)
Amount
Leached
to Water
in Ash
Layer,
per Rain
Event
(mg/m2)
Amount
Filtered
from
Leachate
to Soil,
per Rain
Event
(mg/m2)
Amount
Remain
ing in
Leachate
after
Filter per
Rain
Event
(mg/m2)
Total
Leached
to
Aquifer
First
Rain
Event
(mg)
Fraction
Leached
in Ash
Layer
per Rain
Event
Total
Leached
per Year
(mg)
Total
Inter
cepted by
Well per
Year
(mg)
Ann.
Avg
Cone.
In Well
Water
(mg/L)
Napthalene
1.5E+03
6.9E+00
8.9E+01
3.1E-02
3.0E-02
3.2E-05
7.1E-03
4.6E-06
1.2E+0
2.6E-03
6.3E-09
Acenapthylene
6.2E+01
2.8E-01
2.8E+01
4.0E-03
3.9E-03
1.3E-05
2.9E-03
4.7E-05
4.9E-01
1.1E-03
2.6E-09
Phenanthrene
6.0E+02
2.7E+00
2.0E+03
5.4E-04
5.4E-04
2.5E-08
5.6E-06
9.3E-09
9.3E-04
2.0E-06
4.9E-12
Fluorene
2.1E+02
9.5E-01
5.8E+02
6.5E-04
6.5E-04
1.0E-07
2.3E-05
1.1E-07
3.9E-03
8.6E-06
2.1E-11
Acenaphthene
1.4E+02
6.3E-01
3.7E+02
6.8E-04
6.8E-04
1.7E-07
3.8E-05
2.7E-07
6.4E-03
1.4E-05
3.4E-11
Anthracene
4.1E+02
1.8E+00
1.8E+03
4.1E-04
4.1E-04
2.2E-08
4.8E-06
1.2E-08
8.1E-04
1.8E-06
4.3E-12
Pyrene
3.3E+02
1.5E+00
5.1E+03
1.2E-04
1.2E-04
2.1E-09
4.7E-07
1.4E-09
7.9E-05
1.7E-07
4.2E-13
Chrysene
4.2E+02
1.9E+00
3.0E+04
2.5E-05
2.5E-05
7.6E-11
1.7E-08
4.1E-11
2.8E-06
6.2E-09
1.5E-14
Fluoranthene
3.4E+02
1.5E+00
1.1E+03
5.6E-04
5.6E-04
4.9E-08
1.1E-05
3.2E-08
1.8E-03
4.0E-06
9.6E-12
Benzo[a]antliracene
1.5E+02
6.8E-01
2.7E+04
1.0E-05
1.0E-05
3.5E-11
7.7E-09
5.1E-11
1.3E-06
2.8E-09
6.8E-15
Benzo[a]pyrene
5.1E+02
2.3E+00
7.3E+04
1.3E-05
1.3E-05
1.6E-11
3.6E-09
7.0E-12
6.0E-07
1.3E-09
3.2E-15
Benzo[e]pyrene
1.9E+02
8.4E-01
9.9E+03
3.3E-05
3.3E-05
3.1E-10
7.0E-08
3.7E-10
1.2E-05
2.6E-08
6.2E-14
Benzo [b]fluoranthene
2.2E+02
9.8E-01
7.9E+04
5.0E-06
5.0E-06
5.8E-12
1.3E-09
6.0E-12
2.2E-07
4.8E-10
1.2E-15
Benzo [kjfluoranthene
1.6E+02
7.3E-01
7.4E+04
3.9E-06
3.9E-06
4.8E-12
1.1E-09
6.6E-12
1.8E-07
4.0E-10
9.6E-16
Cyclopenta[c,d]pyrene
2.5E+02
1.1E+00
2.0E+02
2.2E-03
2.2E-03
1.0E-06
2.3E-04
9.1E-07
3.8E-02
8.3E-05
2.0E-10
Perylene
3.1E+02
1.4E+00
2.7E+03
2.1E-04
2.1E-04
7.3E-09
1.6E-06
5.2E-09
2.7E-04
6.0E-07
1.4E-12
Dibenz [a,h] anthracene
5.3E+02
2.4E+00
1.3E+05
7.1E-06
7.1E-06
4.9E-12
1.1E-09
2.0E-12
1.8E-07
4.0E-10
9.6E-16
Indeno [ 1,2,3 -c,d]pyrene
5.0E+02
2.2E+00
2.3E+05
3.8E-06
3.8E-06
1.5E-12
3.4E-10
6.9E-13
5.8E-08
1.3E-10
3.0E-16
Benzo [g,h,i]perylene
2.8E+02
1.3E+00
3.9E+04
1.3E-05
1.3E-05
3.1E-11
7.0E-09
2.5E-11
1.2E-06
2.6E-09
6.2E-15
Benzo [b]chrysene
2.4E+02
1.1E+00
1.3E+03
3.2E-04
3.2E-04
2.3E-08
5.1E-06
2.2E-08
8.6E-04
1.9E-06
4.5E-12
Coronene
2.1E+03
9.4E+00
1.9E+03
2.0E-03
2.0E-03
9.5E-08
2.1E-05
1.0E-08
3.6E-03
7.8E-06
1.9E-11
H-9
-------
Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
A
B
C
D
E
F
G
H
I
J
K
Chemical
Total in
Ash
(mg)
Chem.
per area
(mg /
m2)
Kd
(L/kg)
Amount
Leached
to Water
in Ash
Layer,
per Rain
Event
(mg/m2)
Amount
Filtered
from
Leachate
to Soil,
per Rain
Event
(mg/m2)
Amount
Remain
ing in
Leachate
after
Filter per
Rain
Event
(mg/m2)
Total
Leached
to
Aquifer
First
Rain
Event
(mg)
Fraction
Leached
in Ash
Layer
per Rain
Event
Total
Leached
per Year
(mg)
Total
Inter
cepted by
Well per
Year
(mg)
Ann.
Avg
Cone.
In Well
Water
(mg/L)
Total PAHs
9.2E-09
OctaCDD,
1,2,3,4,6,7,8,9-
1.3E-02
5.7E-05
7.3E+06
3.1E-12
3.1E-12
3.9E-20
8.7E-18
6.8E-16
1.4E-15
3.1E-18
7.5E-24
OctaCDF,
1,2,3,4,6,7,8,9-
8.0E-04
3.6E-06
4.6E+06
3.1E-13
3.1E-13
6.2E-21
1.4E-18
1.7E-15
2.2E-16
4.9E-19
1.2E-24
HeptaCDD,
1,2,3,4,6,7,8-
3.8E-03
1.7E-05
4.6E+06
1.5E-12
1.5E-12
2.9E-20
6.5E-18
1.7E-15
1.1E-15
2.3E-18
5.6E-24
HeptaCDF,
1,2,3,4,6,7,8-
2.5E-03
1.1E-05
1.2E+06
3.9E-12
3.9E-12
3.1E-19
6.9E-17
2.7E-14
1.2E-14
2.5E-17
6.1E-23
HeptaCDF,
1,2,3,4,7,8,9-
7.6E-04
3.4E-06
1.2E+06
1.2E-12
1.2E-12
9.3E-20
2.1E-17
2.7E-14
3.5E-15
7.6E-18
1.8E-23
HexaCDD, 1,2,3,4,7,8-
7.2E-04
3.2E-06
2.9E+05
4.4E-12
4.4E-12
1.4E-18
3.1E-16
4.3E-13
5.2E-14
1.1E-16
2.8E-22
HexaCDF, 1,2,3,4,7,8-
7.6E-04
3.4E-06
4.6E+05
2.9E-12
2.9E-12
5.9E-19
1.3E-16
1.7E-13
2.2E-14
4.8E-17
1.2E-22
HexaCDD, 1,2,3,6,7,8-
4.6E-04
2.1E-06
9.2E+05
9.0E-13
9.0E-13
9.0E-20
2.0E-17
4.3E-14
3.4E-15
7.4E-18
1.8E-23
HexaCDF, 1,2,3,6,7,8-
3.0E-03
1.3E-05
4.6E+05
1.1E-11
1.1E-11
2.3E-18
5.1E-16
1.7E-13
8.5E-14
1.9E-16
4.5E-22
HexaCDD, 1,2,3,7,8,9 -
7.2E-04
3.2E-06
9.2E+05
1.4E-12
1.4E-12
1.4E-19
3.1E-17
4.3E-14
5.2E-15
1.1E-17
2.7E-23
HexaCDF, 1,2,3,7,8,9-
4.2E-04
1.9E-06
4.6E+05
1.6E-12
1.6E-12
3.3E-19
7.3E-17
1.7E-13
1.2E-14
2.7E-17
6.4E-23
PentaCDD, 1,2,3,7,8-
7.2E-04
3.2E-06
2.0E+05
6.3E-12
6.3E-12
2.9E-18
6.5E-16
9.0E-13
1.1E-13
2.4E-16
5.7E-22
PentaCDF, 1,2,3,7,8-
1.7E-03
7.6E-06
2.9E+05
1.1E-11
1.1E-11
3.4E-18
7.6E-16
4.5E-13
1.3E-13
2.8E-16
6.8E-22
HexaCDF, 2,3,4,6,7,8-
5.5E-04
2.5E-06
4.6E+05
2.1E-12
2.1E-12
4.2E-19
9.4E-17
1.7E-13
1.6E-14
3.5E-17
8.4E-23
PentaCDF, 2,3,4,7,8-
1.5E-03
6.6E-06
1.5E+05
1.8E-11
1.8E-11
1.1E-17
2.5E-15
1.7E-12
4.3E-13
9.3E-16
2.3E-21
TetraCDD, 2,3,7,8-
3.4E-04
1.5E-06
2.9E+05
2.1E-12
2.1E-12
6.6E-19
1.5E-16
4.3E-13
2.5E-14
5.4E-17
1.3E-22
TetraCDF, 2,3,7,8-
1.7E-03
7.6E-06
5.8E+04
5.2E-11
5.2E-11
8.2E-17
1.8E-14
1.1E-11
3.1E-12
6.7E-15
1.6E-20
Total Dioxins/furans
2.1E-20
H-10
-------
Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
A
B
C
D
E
F
G
H
I
J
K
Chemical
Total in
Ash
(mg)
Chem.
per area
(mg /
m2)
Kd
(L/kg)
Amount
Leached
to Water
in Ash
Layer,
per Rain
Event
(mg/m2)
Amount
Filtered
from
Leachate
to Soil,
per Rain
Event
(mg/m2)
Amount
Remain
ing in
Leachate
after
Filter per
Rain
Event
(mg/m2)
Total
Leached
to
Aquifer
First
Rain
Event
(mg)
Fraction
Leached
in Ash
Layer
per Rain
Event
Total
Leached
per Year
(mg)
Total
Inter
cepted by
Well per
Year
(mg)
Ann.
Avg
Cone.
In Well
Water
(mg/L)
Arsenic
1.3E+03
5.7E+00
2.9E+01
7.7E-02
7.7E-02
2.5E-04
5.5E-02
4.3E-05
9.2E+0
2.0E-02
4.9E-08
Cadmium
1.3E+03
6.0E+00
7.5E+01
3.2E-02
3.2E-02
3.9E-05
8.7E-03
6.5E-06
1.5E+0
3.2E-03
7.7E-09
Chromium, total
9.9E+04
4.4E+02
1.9E+01
9.1E+00
9.0E+00
4.4E-02
9.8E+00
9.9E-05
1.6E+03
3.6E+00
8.6E-06
Copper
1.3E+05
5.8E+02
4.3E+02
5.4E-01
5.4E-01
1.2E-04
2.6E-02
2.0E-07
4.3E+0
9.4E-03
2.3E-08
Iron
9.5E+06
4.3E+04
6.5E+01
2.6E+02
2.6E+02
3.7E-01
8.2E+01
8.6E-06
1.4E+04
3.0E+01
7.3E-05
Lead
8.5E+03
3.8E+01
9.0E+02
1.7E-02
1.7E-02
1.7E-06
3.8E-04
4.5E-08
6.4E-02
1.4E-04
3.4E-10
Manganese
5.2E+06
2.3E+04
6.5E+01
1.4E+02
1.4E+02
2.0E-01
4.5E+01
8.6E-06
7.6E+03
1.7E+01
4.0E-05
Nickel
3.7E+04
1.7E+02
6.5E+01
1.0E+00
1.0E+00
1.4E-03
3.2E-01
8.6E-06
5.4E+01
1.2E-01
2.9E-07
Mercury
1.4E+00
6.1E-03
2.0E-01
4.0E-03
2.8E-03
1.3E-03
2.8E-01
2.1E-01
1.4E+00
3.0E-03
7.1E-09
Zinc
2.2E+05
9.8E+02
6.2E+01
6.3E+00
6.3E+00
9.3E-03
2.1E+00
9.5E-06
3.5E+02
7.6E-01
1.8E-06
Abbreviations: Chem. = Chemical; Cone. Concentration; PAH = polycyclic aromatic hydrocarbons.
a See Section 4.3.2 of the main report for a description of the methods and calculations used estimate partitioning between ash and infiltrating precipitation and leachate and
subsurface soil.
H-ll
-------
Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Table H.7. Estimated Leaching of Chemicals from Ash and Partitioning with Subsurface Soil - Air-Curtain Burning.3
A
B
C
D
E
F
G
H
I
J
K
Chemical
Total in
Ash
(mg)
Chem.
per area
(mg /
m2)
Kd
(L/kg)
Amount
Leached to
Water in
Ash Layer,
First Rain
Event
(mg/m2)
Amount
Filtered
from
Leachate
to Soil, per
Rain
Event
(mg/m2)
Amount
Remain
ing in
Leachate
After
Filter per
Rain
Event
(mg/m2)
Total
Leached
to
Aquifer,
First
Rain
Event
(mg)
Fraction
Leached
in Ash
Layer per
Rain
Event
Total
Leached
per
Year
(mg)
Total
Inter
cepted
by Well
per Year
(mg)
Ann.
Avg.
Cone. In
Well
Water
(mg/L)
Napthalene
1.2E+03
3.0E+01
8.9E+01
2.4E-02
2.4E-02
2.5E-05
1.0E-03
8.5E-07
1.7E-01
3.1E-03
7.4E-09
Acenapthylene
2.7E+02
6.6E+00
2.8E+01
1.7E-02
1.7E-02
5.8E-05
2.4E-03
8.9E-06
4.0E-01
7.0E-03
1.7E-08
Phenanthrene
9.2E+02
2.2E+01
2.0E+03
8.3E-04
8.3E-04
3.9E-08
1.6E-06
1.7E-09
2.7E-04
4.7E-06
1.1E-11
Fluorene
1.7E+02
4.1E+00
5.8E+02
5.3E-04
5.3E-04
8.4E-08
3.5E-06
2.0E-08
5.8E-04
1.0E-05
2.5E-11
Acenaphthene
3.5E+02
8.6E+00
3.7E+02
1.7E-03
1.7E-03
4.3E-07
1.8E-05
5.0E-08
3.0E-03
5.3E-05
1.3E-10
Anthracene
2.1E+02
5.2E+00
1.8E+03
2.2E-04
2.2E-04
1.1E-08
4.6E-07
2.2E-09
7.8E-05
1.4E-06
3.3E-12
Pyrene
3.3E+02
7.9E+00
5.1E+03
1.1E-04
1.1E-04
2.1E-09
8.5E-08
2.6E-10
1.4E-05
2.5E-07
6.1E-13
Chrysene
1.4E+02
3.4E+00
3.0E+04
8.4E-06
8.4E-06
2.6E-11
1.1E-09
7.5E-12
1.8E-07
3.1E-09
7.6E-15
Fluoranthene
7.1E+02
1.7E+01
1.1E+03
1.2E-03
1.2E-03
1.0E-07
4.2E-06
5.9E-09
7.1E-04
1.2E-05
3.0E-11
Benzo [a] anthracene
7.1E+01
1.7E+00
2.7E+04
4.7E-06
4.7E-06
1.6E-11
6.7E-10
9.4E-12
1.1E-07
2.0E-09
4.7E-15
Benzo[a]pyrene
8.5E+01
2.1E+00
7.3E+04
2.1E-06
2.1E-06
2.7E-12
1.1E-10
1.3E-12
1.8E-08
3.2E-10
7.8E-16
Benzo [e]pyrene
7.1E+01
1.7E+00
9.9E+03
1.3E-05
1.3E-05
1.2E-10
4.9E-09
6.9E-11
8.2E-07
1.4E-08
3.5E-14
Benzo [b] fluoranthene
4.2E+01
1.0E+00
7.9E+04
9.7E-07
9.7E-07
1.1E-12
4.7E-11
1.1E-12
7.9E-09
1.4E-10
3.3E-16
Benzo [kjfluoranthene
3.3E+02
7.9E+00
7.4E+04
7.8E-06
7.8E-06
9.7E-12
4.0E-10
1.2E-12
6.7E-08
1.2E-09
2.8E-15
Cyclopenta[c,d]-
pyrene
9.9E+01
2.4E+00
2.0E+02
8.9E-04
8.8E-04
4.1E-07
1.7E-05
1.7E-07
2.8E-03
4.9E-05
1.2E-10
Perylene
1.1E+02
2.8E+00
2.7E+03
7.6E-05
7.6E-05
2.7E-09
1.1E-07
9.7E-10
1.8E-05
3.2E-07
7.8E-13
Dibenz[a,h]
antliracene
4.2E+01
1.0E+00
1.3E+05
5.7E-07
5.7E-07
3.9E-13
1.6E-11
3.8E-13
2.7E-09
4.7E-11
1.1E-16
Indeno[l,2,3-cd]
pyrene
5.7E+01
1.4E+00
2.3E+05
4.4E-07
4.4E-07
1.8E-13
7.2E-12
1.3E-13
1.2E-09
2.1E-11
5.1E-17
Benzo [g,h,i]perylene
4.2E+02
1.0E+01
3.9E+04
2.0E-05
2.0E-05
4.7E-11
1.9E-09
4.6E-12
3.3E-07
5.7E-09
1.4E-14
Benzo [b] chrysene
2.1E+02
5.2E+00
1.3E+03
2.9E-04
2.9E-04
2.1E-08
8.5E-07
4.0E-09
1.4E-04
2.5E-06
6.1E-12
H-12
-------
Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
A
B
C
D
E
F
G
H
I
J
K
Chemical
Total in
Ash
(mg)
Chem.
per area
(mg /
m2)
Kd
(L/kg)
Amount
Leached to
Water in
Ash Layer,
First Rain
Event
(mg/m2)
Amount
Filtered
from
Leachate
to Soil, per
Rain
Event
(mg/m2)
Amount
Remain
ing in
Leachate
After
Filter per
Rain
Event
(mg/m2)
Total
Leached
to
Aquifer,
First
Rain
Event
(mg)
Fraction
Leached
in Ash
Layer per
Rain
Event
Total
Leached
per
Year
(mg)
Total
Inter
cepted
by Well
per Year
(mg)
Ann.
Avg.
Cone. In
Well
Water
(mg/L)
Coronene
8.5E+02
2.1E+01
1.9E+03
8.0E-04
8.0E-04
3.9E-08
1.6E-06
1.9E-09
2.7E-04
4.7E-06
1.1E-11
Total PAHs
2.5E-08
OctaCDD,
1,2,3,4,6,7,8,9-
1.5E-02
3.6E-04
7.3E+06
3.7E-12
3.7E-12
4.6E-20
1.9E-18
1.3E-16
2.8E-16
4.9E-18
1.2E-23
OctaCDF,
1,2,3,4,6,7,8,9-
9.5E-04
2.3E-05
4.6E+06
3.7E-13
3.7E-13
7.3E-21
3.0E-19
3.2E-16
5.3E-17
9.3E-19
2.2E-24
HeptaCDD,
1,2,3,4,6,7,8-
4.5E-03
1.1E-04
4.6E+06
1.7E-12
1.7E-12
3.5E-20
1.4E-18
3.2E-16
2.5E-16
4.4E-18
1.1E-23
HeptaCDF,
1,2,3,4,6,7,8-
3.0E-03
7.3E-05
1.2E+06
4.6E-12
4.6E-12
3.7E-19
1.5E-17
5.0E-15
2.5E-15
4.4E-17
1.1E-22
HeptaCDF,
1,2,3,4,7,8,9-
9.0E-04
2.2E-05
1.2E+06
1.4E-12
1.4E-12
1.1E-19
4.5E-18
5.0E-15
7.5E-16
1.3E-17
3.2E-23
HexaCDD,
1,2,3,4,7,8-
8.5E-04
2.1E-05
2.9E+05
5.2E-12
5.2E-12
1.6E-18
6.8E-17
8.0E-14
1.1E-14
2.0E-16
4.8E-22
HexaCDF,
1,2,3,4,7,8-
9.0E-04
2.2E-05
4.6E+05
3.5E-12
3.5E-12
7.0E-19
2.9E-17
3.2E-14
4.8E-15
8.4E-17
2.0E-22
HexaCDD,
1,2,3,6,7,8-
5.5E-04
1.3E-05
9.2E+05
1.1E-12
1.1E-12
1.1E-19
4.4E-18
8.0E-15
7.4E-16
1.3E-17
3.1E-23
HexaCDF,
1,2,3,6,7,8-
3.5E-03
8.5E-05
4.6E+05
1.3E-11
1.3E-11
2.7E-18
1.1E-16
3.2E-14
1.9E-14
3.3E-16
7.9E-22
HexaCDD,
1,2,3,7,8,9 -
8.5E-04
2.1E-05
9.2E+05
1.6E-12
1.6E-12
1.6E-19
6.8E-18
8.0E-15
1.1E-15
2.0E-17
4.8E-23
HexaCDF,
1,2,3,7,8,9-
5.0E-04
1.2E-05
4.6E+05
1.9E-12
1.9E-12
3.9E-19
1.6E-17
3.2E-14
2.7E-15
4.7E-17
1.1E-22
PentaCDD, 1,2,3,7,8-
8.5E-04
2.1E-05
2.0E+05
7.5E-12
7.5E-12
3.4E-18
1.4E-16
1.7E-13
2.4E-14
4.2E-16
1.0E-21
PentaCDF, 1,2,3,7,8-
2.0E-03
4.9E-05
2.9E+05
1.3E-11
1.3E-11
4.1E-18
1.7E-16
8.4E-14
2.8E-14
4.9E-16
1.2E-21
HexaCDF,
2,3,4,6,7,8-
6.5E-04
1.6E-05
4.6E+05
2.5E-12
2.5E-12
5.0E-19
2.1E-17
3.2E-14
3.5E-15
6.1E-17
1.5E-22
PentaCDF, 2,3,4,7,8-
1.7E-03
4.2E-05
1.5E+05
2.1E-11
2.1E-11
1.4E-17
5.5E-16
3.2E-13
9.3E-14
1.6E-15
3.9E-21
H-13
-------
Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
A
B
C
D
E
F
G
H
I
J
K
Amount
Leached to
Water in
Ash Layer,
First Rain
Event
(mg/m2)
Amount
Filtered
Amount
Remain
Total
Leached
Fraction
Total
Leached
per
Year
(mg)
Total
Ann.
Chemical
Total in
Ash
(mg)
Chem.
per area
(mg /
m2)
Kd
(L/kg)
from
Leachate
to Soil, per
Rain
Event
(mg/m2)
ing in
Leachate
After
Filter per
Rain
Event
(mg/m2)
to
Aquifer,
First
Rain
Event
(mg)
Leached
in Ash
Layer per
Rain
Event
Inter
cepted
by Well
per Year
(mg)
Avg.
Cone. In
Well
Water
(mg/L)
TetraCDD, 2,3,7,8-
4.0E-04
9.7E-06
2.9E+05
2.4E-12
2.4E-12
7.8E-19
3.2E-17
8.0E-14
5.4E-15
9.4E-17
2.3E-22
TetraCDF, 2,3,7,8-
2.0E-03
4.9E-05
5.8E+04
6.1E-11
6.1E-11
9.7E-17
4.0E-15
2.0E-12
6.7E-13
1.2E-14
2.8E-20
Total Dioxins/furans
3.7E-20
Arsenic
1.5E+03
3.6E+01
2.9E+01
9.2E-02
9.2E-02
2.9E-04
1.2E-02
8.0E-06
2.0E+00
3.5E-02
8.5E-08
Cadmium
6.6E+02
1.6E+01
7.5E+01
1.6E-02
1.6E-02
1.9E-05
8.0E-04
1.2E-06
1.3E-01
2.4E-03
5.7E-09
Chromium, total
1.0E+05
2.5E+03
1.9E+01
9.7E+00
9.7E+00
4.7E-02
1.9E+00
1.9E-05
3.2E+02
5.7E+00
1.4E-05
Copper
1.1E+05
2.6E+03
4.3E+02
4.4E-01
4.4E-01
9.5E-05
3.9E-03
3.7E-08
6.5E-01
1.1E-02
2.8E-08
Iron
7.0E+06
1.7E+05
6.5E+01
1.9E+02
1.9E+02
2.7E-01
1.1E+01
1.6E-06
1.9E+03
3.3E+01
8.0E-05
Lead
1.0E+05
2.5E+03
9.0E+02
2.0E-01
2.0E-01
2.1E-05
8.5E-04
8.4E-09
1.4E-01
2.5E-03
6.0E-09
Manganese
6.1E+06
1.5E+05
6.5E+01
1.7E+02
1.7E+02
2.4E-01
9.9E+00
1.6E-06
1.7E+03
2.9E+01
7.0E-05
Nickel
3.3E+04
8.1E+02
6.5E+01
9.1E-01
9.1E-01
1.3E-03
5.3E-02
1.6E-06
8.9E+00
1.6E-01
3.8E-07
Mercury
1.6E+00
3.9E-02
2.0E-01
1.0E-02
7.1E-03
3.3E-03
1.4E-01
8.5E-02
1.6E+00
2.8E-02
6.7E-08
Zinc
4.8E+05
1.2E+04
6.2E+01
1.4E+01
1.4E+01
2.1E-02
8.6E-01
1.8E-06
1.4E+02
2.5E+00
6.1E-06
Abbreviations: Chem = Chemical; Cone Concentration; PAH = polycyclic aromatic hydrocarbons.
a See Section 4.3.2 of the main report for a description of the methods and calculations used estimate partitioning between ash and infiltrating precipitation and leachate and
subsurface soil.
Table H.8. Documentation of Columns in Tables H.6 and H.7.
Column in
Tables H.6 and
H.7
Description of Column Data or Calculation
Origin of Equation Parameters
A
Total mg of chemical in ash
From Table H.4 and Table H.5
B
Chemical per nf in the ash disposal area (mg/m2)
Col. A divided by ash disposal area from Table H.2
C
Chemical-specific solid/liquid partition coefficient (Kd)
Kd values from literature and chemical databases
D
Rearrange Kd equation to estimate chemical leached to infiltrating precipitation
from ash per rain event. See Section 4.3.2 of the main report, (mg/m2)
(P7 from Table H.3 x Col. B ) / (P12 from Table H.3 x
Col. C + P7 from Table H.3); See Section 4.3.2 of the
main report
H-14
-------
Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Column in
Tables H.6 and
H.7
Description of Column Data or Calculation
Origin of Equation Parameters
E
Rearrange Kd equation to estimate fraction of chemical in leachate that partitions
to vadose zone soil beneath the ash. A layer is the depth of soil saturated by the
volume of leachate in a 1 nf area from the first rain event, (mg/m2)
[Col. C x (P12 from Table H.3) x Col. D] / [P7 from
Table H.3 + Col. C xP12 from Table H.3]; See
Section 4.3.2 of the main report
F
Amount of chemical remaining in leachate after partitioning with soil, per nf and
for the first rain event, (mg/m2)
Col. D - Col. E
G
Total leached to groundwater in the first rain event (mg/event)
Col. F x ash disposal area from Table H.2
H
Fraction of chemical in ash that reaches groundwater per rain event, (unitless)
Col. G/Col. A
I
Total amount of chemical leached to ground water in first 1 year, (mg/yr)
Col. A - (Col. A x (l-(Col. H))AP2 in Table H.3)
J
Amount of chemical intercepted by the drinking water well per year (mg/yr)
(Col. I x (fraction plume intercepted)]
See Section 4.3.5 for further discussion of methods for
well water concentrations.
Fraction of plume intercepted (See Section 4.3.5):
• burial scenario - 0.0022
• storage pile scenario - 0.0050
• windrow scenario - 0.0033
K
Average chemical concentration (mg/L) in drinking water
[(Col J ) / (1,136 L/d x 365 d/yr)
Abbreviations: A = raised to the power of; Col. = column; d = day; Kd = soil-water partitioning coefficient; yr = year.
H-15
-------
Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Appendix I. Supporting Information for Groundwater
Recharge to Surface Water
Concentrations of chemicals in surface water from groundwater recharge to the on-site lake were
estimated for leaching from combustion ash, carcass burial, the compost windrow, or temporary
carcass pile. Concentrations were estimated by dividing the mass of chemical (mg) that reached
groundwater for each option by the volume of the lake converted to L. These estimates were
made for two lake sizes, 40.5 ha and 4.05 ha (100 acres and 10 acres). Calculations to estimate
the chemical mass leached from carcass burial, composting, and temporary carcass storage that
reached groundwater are presented in Appendix G and for ash burial from the combustion-based
options in Appendix H. The lake volumes and related parameters are presented in Table 1.1.
Concentration estimates are presented in Tables 1.2 through 1.6
Table 1.1. Lake Parameters used to Estimate Chemical Concentrations in Surface Water
from Groundwater Recharge.
Lake Parameter
40.5 ha Lake (100 ac)
4.05 ha Lake (10 ac)
Surface Area (m2)
404,686
40,469
Average Depth (m)
4.38
3.02
Volume (L)
1.8E+09
1.2E+08
Abbreviations: ha = hectares; ac = acres.
1-1
-------
Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Table 1.2. Groundwater Recharge to Lake with Chemicals from Leachate from Buried Carcasses.
A
B
C
D
E
F
G
H
I
Chemical
Chemical Reaching Groundwater Minus
Well Intercept (mg/time period)
Concentration in Small Lake (mg/L)
Concentration in Large Lake (mg/L)
First Week
First Two
Months
First Year
First Week
First Two
Months
First Year
First Week
First Two
Months
First Year
aluminum
2.2E-01
7.4E-01
1.0E+00
1.8E-09
6.1E-09
8.5E-09
1.2E-10
4.2E-10
5.9E-10
ammonium
5.9E+06
3.0E+07
1.2E+08
4.9E-02
2.5E-01
9.5E-01
3.3E-03
1.7E-02
6.6E-02
barium
1.4E+00
8.8E+00
1.1E+01
1.2E-08
7.2E-08
8.7E-08
7.9E-10
4.9E-09
6.0E-09
beryllium
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
bicarbonate
1.9E+08
5.0E+08
1.1E+09
1.5E+00
4.1E+00
9.4E+00
1.1E-01
2.8E-01
6.5E-01
boron
0.0E+00
3.2E+03
7.1E+03
0.0E+00
2.6E-05
5.8E-05
0.0E+00
1.8E-06
4.0E-06
cadmium
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
calcium
6.8E+04
1.5E+05
4.0E+05
5.6E-04
1.2E-03
3.3E-03
3.9E-05
8.2E-05
2.2E-04
chloride
3.0E+06
1.0E+07
2.6E+07
2.4E-02
8.4E-02
2.2E-01
1.7E-03
5.8E-03
1.5E-02
chromium
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
cobalt
4.3E-01
0.0E+00
2.3E-01
3.5E-09
0.0E+00
1.9E-09
2.4E-10
0.0E+00
1.3E-10
copper
2.7E-01
1.6E+00
4.5E+00
2.2E-09
1.3E-08
3.7E-08
1.5E-10
9.1E-10
2.5E-09
inorganic C
5.2E+07
1.2E+08
2.5E+08
4.2E-01
9.6E-01
2.0E+00
2.9E-02
6.6E-02
1.4E-01
organic C
3.2E+08
6.7E+08
1.5E+09
2.6E+00
5.5E+00
1.2E+01
1.8E-01
3.8E-01
8.5E-01
iron
3.3E+02
7.9E+02
1.2E+03
2.7E-06
6.4E-06
1.0E-05
1.8E-07
4.4E-07
7.1E-07
lead
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
magnesium
3.4E+04
9.2E+04
2.0E+05
2.8E-04
7.6E-04
1.6E-03
1.9E-05
5.2E-05
1.1E-04
manganese
1.5E+00
4.7E+00
1.0E+01
1.2E-08
3.9E-08
8.5E-08
8.4E-10
2.7E-09
5.8E-09
mercury
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
molybdenum
2.1E+03
2.6E+03
1.9E+03
1.7E-05
2.2E-05
1.6E-05
1.2E-06
1.5E-06
1.1E-06
nickel
1.2E+00
3.0E+00
2.5E+00
9.7E-09
2.4E-08
2.1E-08
6.7E-10
1.7E-09
1.4E-09
nitrate/nitrite
2.6E+04
5.2E+04
6.2E+04
2.1E-04
4.2E-04
5.1E-04
1.5E-05
2.9E-05
3.5E-05
total N
1.4E+08
2.3E+08
4.9E+08
1.1E+00
1.8E+00
4.0E+00
7.7E-02
1.3E-01
2.8E-01
phosphorus
1.0E+06
4.6E+06
1.2E+07
8.6E-03
3.8E-02
1.0E-01
5.9E-04
2.6E-03
7.0E-03
potassium
2.2E+06
8.1E+06
2.2E+07
1.8E-02
6.6E-02
1.8E-01
1.2E-03
4.5E-03
1.2E-02
selenium
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
silicon
3.3E+04
1.1E+05
2.5E+05
2.7E-04
8.7E-04
2.1E-03
1.9E-05
6.0E-05
1.4E-04
silver
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
1-2
-------
Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
A
B
C
D
E
F
G
H
I
Chemical
Chemical Reaching Groundwater Minus
Well Intercept (mg/time period)
Concentration in Small Lake (mg/L)
Concentration in Large Lake (mg/L)
First Week
First Two
Months
First Year
First Week
First Two
Months
First Year
First Week
First Two
Months
First Year
sodium
1.8E+06
8.3E+06
2.1E+07
1.5E-02
6.8E-02
1.7E-01
1.0E-03
4.7E-03
1.2E-02
strontium
8.0E+02
1.7E+03
3.1E+03
6.5E-06
1.4E-05
2.5E-05
4.5E-07
9.7E-07
1.8E-06
sulphate
8.2E+06
3.3E+07
8.2E+07
6.7E-02
2.7E-01
6.7E-01
4.6E-03
1.9E-02
4.6E-02
sulphur
1.4E+06
6.3E+06
1.8E+07
1.1E-02
5.2E-02
1.4E-01
7.7E-04
3.6E-03
1.0E-02
titanium
2.3E+02
0.0E+00
8.8E+01
1.9E-06
0.0E+00
7.2E-07
1.3E-07
0.0E+00
5.0E-08
vanadium
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
0.0E+00
zinc
1.1E+01
4.5E+01
1.1E+02
8.9E-08
3.7E-07
8.7E-07
6.1E-09
2.6E-08
6.0E-08
zirconium
2.3E+02
0.0E+00
8.8E+01
1.9E-06
0.0E+00
7.2E-07
1.3E-07
0.0E+00
5.0E-08
1-3
-------
Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Table 1.3. Groundwater Recharge to Lake with Chemicals from Leachate from Carcass
Storage Pile During First Two Days.
A
D
G
Chemical
Chemical Reaching Groundwater
Minus Well Intercept (mg/time
period)
Concentration in Small
Lake (mg/L)
Concentration in Large
Lake (mg/L)
Aluminum
2.2E-01
1.8E-09
1.3E-10
Ammonium
4.3E+06
3.5E-02
2.4E-03
Barium
1.4E+00
1.2E-08
8.1E-10
Beryllium
0.0E+00
0.0E+00
0.0E+00
Bicarbonate
6.7E+07
5.5E-01
3.8E-02
Boron
0.0E+00
0.0E+00
0.0E+00
Cadmium
0.0E+00
0.0E+00
0.0E+00
Calcium
5.0E+04
4.1E-04
2.8E-05
Chloride
2.2E+06
1.8E-02
1.2E-03
Chromium
0.0E+00
0.0E+00
0.0E+00
Cobalt
4.4E-01
3.6E-09
2.5E-10
Copper
2.7E-01
2.2E-09
1.5E-10
Inorganic C
1.5E+07
1.2E-01
8.3E-03
Organic C
9.1E+07
7.5E-01
5.1E-02
Iron
3.3E+02
2.7E-06
1.9E-07
Lead
0.0E+00
0.0E+00
0.0E+00
Magnesium
2.5E+04
2.0E-04
1.4E-05
Manganese
1.5E+00
1.2E-08
8.5E-10
Mercury
0.0E+00
0.0E+00
0.0E+00
Molybdenum
1.5E+03
1.2E-05
8.5E-07
Nickel
1.2E+00
9.9E-09
6.8E-10
Nitrate/Nitrite
1.9E+04
1.6E-04
1.1E-05
Total N
3.9E+07
3.2E-01
2.2E-02
Phosphorus
7.7E+05
6.3E-03
4.3E-04
Potassium
1.6E+06
1.3E-02
8.9E-04
Selenium
0.0E+00
0.0E+00
0.0E+00
Silicon
2.4E+04
2.0E-04
1.4E-05
Silver
0.0E+00
0.0E+00
0.0E+00
Sodium
1.3E+06
1.1E-02
7.5E-04
Strontium
5.8E+02
4.8E-06
3.3E-07
Sulphate
4.7E+06
3.9E-02
2.7E-03
Sulphur
1.0E+06
8.2E-03
5.6E-04
Titanium
1.7E+02
1.4E-06
9.4E-08
Vanadium
0.0E+00
0.0E+00
0.0E+00
Zinc
1.1E+01
9.1E-08
6.2E-09
Zirconium
1.7E+02
1.4E-06
9.4E-08
1-4
-------
Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Table 1.4. Groundwater Recharge to Lake with Chemicals from Leachate from Windrow
During First Year.
A
D
G
Chemical
Chemical Reaching Groundwater
Minus Well Intercept (mg/time
period)
Concentration in Small
Lake (mg/L)
Concentration in Large
Lake (mg/L)
Aluminum
5.2E-02
4.2E-10
2.9E-11
Ammonium
5.8E+06
4.8E-02
3.3E-03
Barium
5.3E-01
4.4E-09
3.0E-10
Beryllium
na
na
na
Bicarbonate
5.7E+07
4.7E-01
3.2E-02
Boron
3.5E+02
2.9E-06
2.0E-07
Cadmium
0.0E+00
0.0E+00
0.0E+00
Calcium
2.0E+04
1.6E-04
1.1E-05
Chloride
1.3E+06
1.1E-02
7.4E-04
Chromium
0.0E+00
0.0E+00
0.0E+00
Cobalt
1.2E-02
9.4E-11
6.5E-12
Copper
2.2E-01
1.8E-09
1.3E-10
Inorganic C
1.2E+07
1.0E-01
7.0E-03
Organic C
7.5E+07
6.1E-01
4.2E-02
Iron
6.2E+01
5.1E-07
3.5E-08
Lead
0.0E+00
0.0E+00
0.0E+00
Magnesium
1.0E+04
8.2E-05
5.6E-06
Manganese
5.2E-01
4.2E-09
2.9E-10
Mercury
0.0E+00
0.0E+00
0.0E+00
Molybdenum
9.6E+01
7.8E-07
5.4E-08
Nickel
1.3E-01
1.0E-09
7.1E-11
Nitrate/Nitrite
3.1E+03
2.5E-05
1.8E-06
Total N
2.5E+07
2.0E-01
1.4E-02
Phosphorus
6.2E+05
5.1E-03
3.5E-04
Potassium
1.1E+06
9.0E-03
6.2E-04
Selenium
0.0E+00
0.0E+00
0.0E+00
Silicon
1.3E+04
1.0E-04
7.2E-06
Silver
0.0E+00
0.0E+00
0.0E+00
Sodium
1.1E+06
8.7E-03
6.0E-04
Strontium
1.6E+02
1.3E-06
8.8E-08
Sulphate
4.1E+06
3.3E-02
2.3E-03
Sulphur
8.8E+05
7.2E-03
5.0E-04
Titanium
4.4E+00
3.6E-08
2.5E-09
Vanadium
0.0E+00
0.0E+00
0.0E+00
Zinc
5.3E+00
4.3E-08
3.0E-09
Zirconium
4.4E+00
3.6E-08
2.5E-09
Abbreviations: na = not analyzed.
1-5
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Table 1.5. Groundwater Recharge to Lake with Chemicals Leached from Ash Buried After
Open Burning.
A
B
C
Chemical (number of rings)
Chemical Reaching
Groundwater Minus Well
Intercept (mg/yr)
Concentration in
Small Lake (mg/L)
Concentration in Large
Lake (mg/L)
Napthalene (2)
1.2E+00
9.7E-09
6.7E-10
Acenapthylene (3)
4.9E-01
4.0E-09
2.8E-10
Phenanthrene (3)
9.3E-04
7.6E-12
5.3E-13
Fluorene (3)
3.9E-03
3.2E-11
2.2E-12
Acenaphthene (3)
6.4E-03
5.3E-11
3.6E-12
Anthracene (3)
8.1E-04
6.7E-12
4.6E-13
Pyrene (4)
7.9E-05
6.5E-13
4.5E-14
Chrysene (4)
2.8E-06
2.3E-14
1.6E-15
Fluoranthene (4)
1.8E-03
1.5E-11
1.0E-12
Benzo[a]anthracene (4)
1.3E-06
1.1E-14
7.3E-16
Benzo[a]pyrene (5)
6.0E-07
4.9E-15
3.4E-16
Benzo[e]pyrene (5)
1.2E-05
9.6E-14
6.6E-15
Benzo[b]fluoranthene (5)
2.2E-07
1.8E-15
1.2E-16
Benzo[k]fluoranthene (5)
1.8E-07
1.5E-15
1.0E-16
Cyclopenta[c,d]pyrene (5)
3.8E-02
3.1E-10
2.1E-11
Perylene (5)
2.7E-04
2.2E-12
1.5E-13
Dibenz[a,h]anthracene (6)
1.8E-07
1.5E-15
1.0E-16
Indeno[l,2,3-c,d] pyrene (6)
5.7E-08
4.7E-16
3.2E-17
Benzo[g,h,i]perylene (6)
1.2E-06
9.6E-15
6.6E-16
Benzo[b]chrysene (6)
8.6E-04
7.0E-12
4.8E-13
Coronene (7)
3.5E-03
2.9E-11
2.0E-12
OctaCDD, 1,2,3,4,6,7,8,9-
1.4E-15
1.2E-23
8.0E-25
OctaCDF, 1,2,3,4,6,7,8,9-
2.2E-16
1.8E-24
1.3E-25
HeptaCDD, 1,2,3,4,6,7,8-
1.1E-15
8.7E-24
6.0E-25
HeptaCDF, 1,2,3,4,6,7,8-
1.2E-14
9.5E-23
6.6E-24
HeptaCDF, 1,2,3,4,7,8,9-
3.5E-15
2.8E-23
2.0E-24
HexaCDD, 1,2,3,4,7,8-
5.2E-14
4.3E-22
2.9E-23
HexaCDF, 1,2,3,4,7,8-
2.2E-14
1.8E-22
1.2E-23
HexaCDD, 1,2,3,6,7,8-
3.4E-15
2.8E-23
1.9E-24
HexaCDF, 1,2,3,6,7,8-
8.5E-14
7.0E-22
4.8E-23
HexaCDD, 1,2,3,7,8,9 -
5.2E-15
4.3E-23
2.9E-24
HexaCDF, 1,2,3,7,8,9-
1.2E-14
1.0E-22
6.9E-24
PentaCDD, 1,2,3,7,8-
1.1E-13
8.9E-22
6.1E-23
PentaCDF, 1,2,3,7,8-
1.3E-13
1.0E-21
7.2E-23
HexaCDF, 2,3,4,6,7,8-
1.6E-14
1.3E-22
8.9E-24
PentaCDF, 2,3,4,7,8-
4.3E-13
3.5E-21
2.4E-22
TetraCDD, 2,3,7,8-
2.4E-14
2.0E-22
1.4E-23
1-6
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
A
B
C
Chemical (number of rings)
Chemical Reaching
Groundwater Minus Well
Intercept (mg/yr)
Concentration in
Small Lake (mg/L)
Concentration in Large
Lake (mg/L)
TetraCDF, 2,3,7,8-
3.1E-12
2.5E-20
1.7E-21
Arsenic
9.2E+00
7.5E-08
5.2E-09
Cadmium
1.5E+00
1.2E-08
8.2E-10
Chromium, total
1.6E+03
1.3E-05
9.2E-07
Copper
4.3E+00
3.5E-08
2.4E-09
Iron
1.4E+04
1.1E-04
7.8E-06
Lead
6.4E-02
5.3E-10
3.6E-11
Manganese
7.6E+03
6.2E-05
4.3E-06
Nickel
5.4E+01
4.4E-07
3.0E-08
Mercury
1.3E+00
1.1E-08
7.6E-10
Zinc
3.5E+02
2.9E-06
2.0E-07
Abbreviations: PAH = polycyclic aromatic hydrocarbons; yr = year.
1-7
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Table 1.6. Groundwater Recharge to Lake with Chemicals Leached from Ash Buried After
Air-Curtain Burning.
A
B
C
Chemical (number of
rings)
Chemical Reaching
Groundwater Minus Well
Intercept (mg/yr)
Concentration in
Small Lake (mg/L)
Concentration in Large
Lake (mg/L)
Napthalene (2)
1.7E-01
1.4E-09
9.7E-11
Acenapthylene (3)
3.9E-01
3.2E-09
2.2E-10
Phenanthrene (3)
2.6E-04
2.1E-12
1.5E-13
Fluorene (3)
5.7E-04
4.7E-12
3.2E-13
Acenaphthene (3)
2.9E-03
2.4E-11
1.7E-12
Anthracene (3)
7.7E-05
6.3E-13
4.3E-14
Pyrene (4)
1.4E-05
1.2E-13
7.9E-15
Chrysene (4)
1.8E-07
1.4E-15
9.9E-17
Fluoranthene (4)
6.9E-04
5.7E-12
3.9E-13
Benzo[a]anthracene (4)
1.1E-07
9.0E-16
6.2E-17
Benzo[a]pyrene (5)
1.8E-08
1.5E-16
1.0E-17
Benzo[e]pyrene (5)
8.1E-07
6.6E-15
4.6E-16
Benzo[b]fluoranthene (5)
7.7E-09
6.3E-17
4.4E-18
Benzo[k]fluoranthene (5)
6.6E-08
5.4E-16
3.7E-17
Cyclopenta[c,d]pyrene (5)
2.8E-03
2.3E-11
1.6E-12
Perylene (5)
1.8E-05
1.5E-13
1.0E-14
Dibenz[a,h]anthracene (6)
2.6E-09
2.2E-17
1.5E-18
Indeno[l,2,3-c,d] pyrene (6)
1.2E-09
9.8E-18
6.7E-19
Benzo[g,h,i]perylene (6)
3.2E-07
2.6E-15
1.8E-16
Benzo[b]chrysene (6)
1.4E-04
1.2E-12
7.9E-14
Coronene (7)
2.6E-04
2.1E-12
1.5E-13
OctaCDD, 1,2,3,4,6,7,8,9-
2.7E-16
2.2E-24
1.5E-25
OctaCDF, 1,2,3,4,6,7,8,9-
5.2E-17
4.3E-25
2.9E-26
HeptaCDD, 1,2,3,4,6,7,8-
2.5E-16
2.0E-24
1.4E-25
HeptaCDF, 1,2,3,4,6,7,8-
2.5E-15
2.0E-23
1.4E-24
HeptaCDF, 1,2,3,4,7,8,9-
7.4E-16
6.1E-24
4.2E-25
HexaCDD, 1,2,3,4,7,8-
1.1E-14
9.1E-23
6.3E-24
HexaCDF, 1,2,3,4,7,8-
4.7E-15
3.9E-23
2.7E-24
HexaCDD, 1,2,3,6,7,8-
7.2E-16
5.9E-24
4.1E-25
HexaCDF, 1,2,3,6,7,8-
1.8E-14
1.5E-22
1.0E-23
HexaCDD, 1,2,3,7,8,9 -
1.1E-15
9.1E-24
6.3E-25
HexaCDF, 1,2,3,7,8,9-
2.6E-15
2.1E-23
1.5E-24
PentaCDD, 1,2,3,7,8-
2.3E-14
1.9E-22
1.3E-23
PentaCDF, 1,2,3,7,8-
2.8E-14
2.3E-22
1.6E-23
HexaCDF, 2,3,4,6,7,8-
3.4E-15
2.8E-23
1.9E-24
PentaCDF, 2,3,4,7,8-
9.2E-14
7.5E-22
5.2E-23
1-8
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
A
B
C
Chemical (number of
rings)
Chemical Reaching
Groundwater Minus Well
Intercept (mg/yr)
Concentration in
Small Lake (mg/L)
Concentration in Large
Lake (mg/L)
TetraCDD, 2,3,7,8-
5.3E-15
4.3E-23
3.0E-24
TetraCDF, 2,3,7,8-
6.6E-13
5.4E-21
3.7E-22
Arsenic
2.0E+00
1.6E-08
1.1E-09
Cadmium
1.3E-01
1.1E-09
7.4E-11
Cliromium, total
3.2E+02
2.6E-06
1.8E-07
Copper
6.4E-01
5.2E-09
3.6E-10
Iron
1.8E+03
1.5E-05
1.0E-06
Lead
1.4E-01
1.1E-09
7.9E-11
Manganese
1.6E+03
1.3E-05
9.2E-07
Nickel
8.8E+00
7.2E-08
5.0E-09
Mercury
1.6E+00
1.3E-08
8.8E-10
Zinc
1.4E+02
1.2E-06
8.0E-08
Abbreviations: PAH = polycyclic aromatic hydrocarbons.
1-9
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Appendix J. Aquatic Food Web Modeling
J.l. Approach for Inorganic Chemicals
3.2. We present bioaccumulation factors (BAFs) for metals in fish at
trophic levels 3 and 4 (TL3 and TL4), along with the sources for these
input values, in Table Jl, belowApproach for Organic Chemicals
Fish tissue concentrations of organic chemicals in the on-site lake were modeled with
AQUAWEB 1.2 (Arnot and Gobas 2004). The biokinetic model calculates a steady-state solution
using algorithms for chemical uptake, transformation, and loss by various biological processes
by both benthic invertebrates and benthic and pelagic (i.e., water column) fish. Required inputs,
chemical concentrations in both the water column and bottom sediments, are calculated by the
HHRAP SSW Screening Model as described in Appendices E and F. In addition, AQUAWEB
uses chemical-specific Kow values to calculate partitioning of the chemical between particle-
phase and aqueous-phase in the water column compartment and in the sediment compartment.
. For inorganic elements below, bioaccumulation depends on chemical speciation in water (and
sediments), the fraction that is bioavailable (i.e., dissolved in water), and the overall number of
species in the food "chain" (more accurately a food web) supporting the fish species.
Table J.l. Bioaccumulation Factors for Inorganic Chemicals - Open Burning Option.3
Chemical
BAF for
TL4 (L/kg)
BAF for
TL3 (L/kg)
Reference
Fish in Water
Column
(Walleye) TL4;
jig/kg ww
Bottom fish
(Yellow Bullhead)
TL3; ju.g/kg ww
Cadmium
40
40
CAOEHHA 2012
5.8E-03
5.8E-03
Chromium
225
225
Eneji et al. 2011
1.4E+00
1.4E+00
Copper
150
150
Eneji et al. 2011
3.9E-01
3.9E-01
Iron
120
120
Eneji et al. 2011
1.7E+02
1.7E+02
Lead
20
20
CAOEHHA 2012
2.4E-03
2.4E-03
Manganese
30
30
Eneji et al. 2011
1.5E-01
1.5E-01
Nickel
20
20
CAOEHHA 2012
2.9E-02
2.9E-02
Zinc
230
230
Eneji et al. 2011
2.5E+00
2.5E+00
Arsenic
17
17
CAOEHHA 2012
3.9E-03
3.9E-03
Abbreviations: BAF = bioaccumulation factor; TL4 = trophic level four; TL3 = trophic level three; ww = wet weight.
a Estimated concentrations in fish for other scenarios are presented in Table 4.5 of the main report.
J-l
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
J J. The concentration of many Inorganics actually decreases with
Increasing trophic level (e.g., arsenic; Chen and Foil 2000) due to limited
absorption of Inorganic chemicals via the gastrointestinal tract. Readily
available data for the other elementsApproach for Organic Chemicals
Fish tissue concentrations of organic chemicals in the on-site lake were modeled with
AQUAWEB 1.2 (Arnot and Gobas 2004). The biokinetic model calculates a steady-state solution
using algorithms for chemical uptake, transformation, and loss by various biological processes
by both benthic invertebrates and benthic and pelagic (i.e., water column) fish. Required inputs,
chemical concentrations in both the water column and bottom sediments, are calculated by the
HHRAP SSW Screening Model as described in Appendices E and F. In addition, AQUAWEB
uses chemical-specific Kow values to calculate partitioning of the chemical between particle-
phase and aqueous-phase in the water column compartment and in the sediment compartment.
, however, did not distinguish metal BAFs by trophic level. We therefore we assume the same
BAF for TL3 and TL4 fish feeding primarily in the benthos and in the water column,
respectively. Methyl mercury, which does bioaccumulate to higher concentrations at higher
trophic levels, is not evaluated because it has been banned from animal feeds for many years, and
because it is ubiquitous in the atmosphere globally from many emission sources.
J.4. BAFs for essent trients and some trace elements tend to
decrease with Increasing concentration. This Indicates biological
regulation of absorption and elimination rates, particularly ftw fish in
freshwater. Empirical equations that would predict BAF values on the
basis of water concentration were not found or determined. As a
conservative approach, the BAF values for Inorganic chemicals In
Approach for Organic Chemicals
Fish tissue concentrations of organic chemicals in the on-site lake were modeled with
AQUAWEB 1.2 (Arnot and Gobas 2004). The biokinetic model calculates a steady-state solution
using algorithms for chemical uptake, transformation, and loss by various biological processes
by both benthic invertebrates and benthic and pelagic (i.e., water column) fish. Required inputs,
chemical concentrations in both the water column and bottom sediments, are calculated by the
HHRAP SSW Screening Model as described in Appendices E and F. In addition, AQUAWEB
uses chemical-specific Kow values to calculate partitioning of the chemical between particle-
phase and aqueous-phase in the water column compartment and in the sediment compartment.
J-2
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
are multiplied by the total water concentration for the chemical (i.e., dissolved plus particulate
phase) instead of by the dissolved concentration for the chemical.
J.5. Approach for Organic Chemicals
Fish tissue concentrations of organic chemicals in the on-site lake were modeled with
AQUAWEB 1.2 (Arnot and Gobas 2004). The biokinetic model calculates a steady-state solution
using algorithms for chemical uptake, transformation, and loss by various biological processes
by both benthic invertebrates and benthic and pelagic (i.e., water column) fish. Required inputs,
chemical concentrations in both the water column and bottom sediments, are calculated by the
HHRAP SSW Screening Model as described in Appendices E and F. In addition, AQUAWEB
uses chemical-specific Kow values to calculate partitioning of the chemical between particle-
phase and aqueous-phase in the water column compartment and in the sediment compartment.
AQUAWEB Version 1.2 is used exactly as developed. That is, we did not change the
AQUAWEB model framework or equations. The model is well-documented in the peer-
reviewed literature. This section is an overview of the model structure and key model inputs (i.e.,
specification of invertebrate and fish species, their characteristics, and the structure of the food
web). The user is encouraged to consult the AQUAWEB website and other sources cited here for
additional information.
Given the chemical's concentration in the water column and the sediment and chemical Kow
values, AQUAWEB uses a series of submodels to estimate the rate constants representing the
fish's processes of chemical uptake through ingestion and respiration, chemical elimination
through excretion and respiration, and metabolic transformation. The food webs in the
AQUAWEB model include 21 separate biotic compartments (1 algal, 1 zooplankton, 5 other
invertebrate, and 14 fish) that can be simulated using separate body sizes, metabolic capabilities,
lipid content, dietary preferences, and source of prey (benthic or pelagic). Inputs to AQUAWEB
assumed for this project are summarized below.
Chemical source terms. Inputs include the total chemical concentration in the water column (in
ng/L) and the total chemical concentration in sediments (in ng/g dry weight). The HHRAP SSW
Screening Model automatically provides those inputs to AQUAWEB. The model assumes that
the chemical concentration specified for the surface water is total chemical, some of which might
J-3
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
be dissolved or sorbed to suspended particles or dissolved organic carbon in the surface water
column and in the sediment compartment.
Physical parameters. The HRAP SSW Screening Model loads the required water-body inputs
into AQUAWEB. The model default parameter values used for the exposure assessment are
shown in Table J.2.
Table 3.2. Input Parameter Values Assumed for the Farm Pond (see Appendix F).
Fate and Transport Parameter
Value
Units
Sediment organic carbon content (fraction)
0.04
unitless
Water body temperature
287.65
°C
Dissolved organic carbon content
1.20E-05
kg/L
Particulate organic carbon content
3.20E-06
kg/L
Total suspended solids
13
kg/L
Abbreviations: L = liters.
As noted above, AQUAWEB requires values for log Kow for organic chemicals, and these
values are specified along with other chemical inputs within the HHRAP SSW Screening Model.
Default values for metabolic transformation rate constants are included in the chemical-specific
input tables in the model.
Aquatic food web. The options for building food webs using AQUAWEB include 21 types of
biotic compartments; however, to keep the food webs relatively simple, not all of these
compartments were used. The default food web (in the online AQUAWEB model) based on the
Great Lakes was not used because food chains are longer in the Great Lakes than in other lakes
in the United States. A 40 hectare lake approximates a size at which TL4 fish populations in the
water column might be readily sustainable without stocking. For each species and size or age
class of animal included in the food web, input values for the diet, body size, fraction lipid, and
fraction of pore water ventilated are drawn from previously compiled data representing small
lakes in southern Minnesota, for which a digitized database for all lakes larger than 10 acres is
available. We present assumptions and input values for the aquatic food web in Table J.3 through
Table J. 5 We model a feasible food "web" rather than simple and separate benthic and pelagic
"straight food chains," because even as adults, most fish species in relatively shallow lakes (e.g.,
<10 meters deep) obtain some fraction of their diet from benthic invertebrates.
J-4
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Fish diets vary substantially with species, age, size, season, lake size (surface area and depth
profile), land uses (e.g., agricultural or not), contributions from and connections with other water
bodies, latitude, and other factors. We based the food web depicted in Table J.5 on the citations
in the table endnotes; however, other scientists might specify different food webs based on the
same data sets. For a previous project, we developed food webs for six different ecoregions in
Minnesota and discovered that the resulting bioaccumulation estimates were relatively
insensitive to the food web structure. Parameters for which the outputs of AQUAWEB are more
sensitive included dissolved and particulate organic matter content and total suspended solids.
Table J.3. Input Parameter Specific to Phytoplankton.
Type
Species Name
Lipid Content
Non lipid
Organic
Carbon
Content
Water Content
Phytoplankton
Growth Rate
Constant
Phytoplankton
Phytoplankton
0.5%
6.5%
93.0%
8.00E-02
Table J.4. Farm Pond Food Web Composition and Properties.
Model
Compartment
Taxon
Filter
Feeder?
Organism Wet
Weight (kg)
Lipid
Content
Fraction Sediment Pore
Water Ventilated
Zooplankton
Zooplankton
TRUE
5.70E-08
1.2%
0.00E+00
Invertebrate 1
Bivalves
TRUE
1.10E-04
1.3%
5.00E-02
Invertebrate 2
Caddisfly larvae
TRUE
4.00E-05
1.7%
5.00E-02
Invertebrate 3
Mayfly larvae
FALSE
1.00E-04
2.0%
5.00E-02
Invertebrate 4
Gammarus (isopod)
FALSE
1.00E-05
2.1%
5.00E-02
Invertebrate 5
Midge larvae
FALSE
4.00E-05
2.0%
5.00E-02
Fish 1
Fish fry
na
4.00E-04
2.0%
0.00E+00
Fish 2
Fingerling fish
na
5.00E-02
2.5%
0.00E+00
Fish 3
N. pike and walleye fingerlings
na
1.20E-01
1.5%
0.00E+00
Fish 4
Black crappie 5-7"
na
1.00E-01
5.0%
0.00E+00
Fish 5
Yellow perch 5-6"
na
1.00E-01
3.5%
0.00E+00
Fish 6
White sucker 6-12"
na
2.28E-01
3.9%
0.00E+00
Fish 7
White sucker 12-16"
na
5.00E-01
5.1%
0.00E+00
Fish 8
N. pike 15-30"
na
1.09E+00
2.9%
0.00E+00
Fish 9
Bluegill 5-8"
na
1.60E-01
5.5%
0.00E+00
Fish 10
Walleye 12-20"
na
7.25E-01
7.9%
0.00E+00
Abbreviations: na = not applicable; N. = northern; " = inches in length.
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Table J.5. On-site Lake Food Web by Animal Group or Species.
Species ^
Phyto
plank
ton
Sedi
ment /
Detrius
Zoo
plank
ton
Bi
valves
Caddisfly
larvae
Mayfly
larvae
Iso
pod
Midge
larvae
Fish
fry
Finger
lings
N. pike &
walleye
fmgerlings
Black
crappie
5 7
Yellow
perch
5 6
White
sucker
6 12
White
sucker
12
16
N.
pike
15
30
Bluegill
5 8
Zooplankton
100%
Bivalves
50%
40%
10%
Caddisfly
larvae
40%
50%
10%
0%
Mayfly
0%
100%
0%
0%
0%
Gammarus
10%
50%
40%
0%
0%
0%
Midge
larvae
40%
60%
0%
0%
0%
0%
0%
Fish fry
30%
0%
70%
0%
0%
0%
0%
0%
Minnows/
fmgerlings
0%
0%
60%
0%
10%
10%
10%
10%
0%
Pike &
walleye
fmgerlings
0%
0%
0%
0%
0%
0%
0%
0%
20%
80%
Black
crappie 5-7"
0%
0%
10%
0%
10%
20%
20%
20%
20%
0%
0%
Yellow
perch 5-6"
0%
0%
0%
0%
20%
20%
20%
20%
20%
0%
0%
0%
White
sucker 6-12"
0%
40%
0%
0%
20%
20%
20%
0%
0%
0%
0%
0%
0%
White
sucker 12-
16"
0%
40%
0%
0%
20%
20%
20%
0%
0%
0%
0%
0%
0%
0%
N. pike 15-
30"
0%
0%
0%
0%
0%
0%
0%
0%
0%
40%
20%
0%
20%
20%
0%
Bluegill 5-
8"
0%
0%
0%
0%
30%
20%
30%
10%
10%
0%
0%
0%
0%
0%
0%
0%
Walleye 12-
20"
0%
0%
0%
0%
0%
5%
0%
0%
10%
60%
5%
0%
20%
0%
0%
0%
0%
J-6
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Table J.5 (continued). Endnotes.
a Consumer organisms listed as row headers (i.e., listed in first column of table). Diet components listed across the top as column headers. Small fish species include bluegill,
crappie, perch, and sucker. Walleye and northern pike fmgerlings feed more on smaller fish than on benthic invertebrates.
k Sources include AQUA WEB defaults for invertebrates, fish fry, and fmgerlings other than walleye and pike. For remaining fish species, data reviewed included compilation of
diet by species and size by Leidy and Jenkings 1977 (data from Great Lakes excluded): northern pike—Seaburg and Moyle 1964, Pearse 1921, Hunt and Carbine 1950; white
sucker—Scidmore and Woods 1960, Pearse 1921; bluegill—Applegate et al. 1967, Seaburg and Moyle 1964, Scidmore and Woods 1960; black crappie—Seaburg and Moyle
1964, Keast 1968; yellow perch—Pearse 1921, Scidmore and Woods 1960; walleye—Scidmore and Woods 1960.
J-7
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
J.6. References
Applegate RL, Mullan JW, Morais DI (1967). Food and growth of six centrarchids from
shoreline areas of Bull Shoals Reservoir. Proc Annu Conf Southeast Assoc Game Fish Comm.
20: 469-482. As cited by Leidy and Jenkins 1977.
Arnot JA, Gobas, FAPC. 2004. A food web bioaccumulation model for organic chemicals in
aquatic ecosystems. Environ Toxicol Chem 23(10): 2343-2355.
CAOEHHA (California Office of Environmental Health Hazard Assessment) (2012). Technical
Support Document for Exposure Assessment and Stochastic Analysis, Final. Appendix I. Fish
Bioaccumulation Factors.
Eneji IS, Ato RS, Annune PA (2011). Bioaccumulation of heavy metals in fish (Tilapia Zilli and
Clarias Gariepinus) organs from River Benue, North-Central Nigeria. PakJ Anal Environ Chem
12(1,2): 25-31.
Hunt BP, Carbine WF (1950). Food and feeding habits of young pike Esox Lucius L., and
associated fishes in Peterson's Ditches, Houghton Lake, Michigan. Trans Am Fish Soc 80: 67-
83. Cited by Leidy and Jenkins 1977.
Keast A (1968). Feeding biology of the black crappie, Pomoxis nigromaculatus. J Fish Res
Board Canada 25(2): 285-297. As cited by Leidy and Jenkins 1977.
Leidy JR, Jenkins RM (1977). The Development of Fishery Compartments and Population Rate
Coefficients for Use in Reservoir Ecosystem Modeling. US Department of Interior Fish and
Wildlife Service, National Reservoir Research Program, Fayetteville, Arkansas. Report No. Y-
77-1. June.
Pearse AS (1921). Distribution and food of the fishes of Green Lake, Wisconsin, in summer.
U.S. Bureau of Fisheries Bulletin 37: 253-272. As cited by Leidy and Jenkins 1977.
Scidmore WJ, Woods DE (1960). Some observations on competition between several species of
fish for summer foods in four Minnesota lakes in 1955, 1956, and 1957. Minn Fish Game Invest
Fish Ser. No. 2: 13-24. As cited by Leidy and Jenkins 1977.
J-8
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Seaburg KG, Moyle JB (1964). Feeding habits, digestion rates, and growth of some Minnesota
warmwater fishes. Trans Am Fish Soc 93: 269-285. Cited by Leidy and Jenkins 1977.
J-9
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
i ;>jp
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
report. Although MIRC can provide human health risk estimates, this assessment uses MIRC
only to estimate chemical exposure levels.
MIRC was developed to be a flexible, transparent application. The tool includes chemical
transfer and ingestion exposure algorithms and a database of parameter values, many with
several options, used by these equations. The MIRC database includes values for the relevant
physiochemical properties and toxicity reference values for more than 500 chemicals, including
approximately 60 inorganics taken primarily from a database developed for HHRAP (USEPA
2005a).
K.1.1. Scope of MIRC
For persistent and bioaccumulative chemicals, including PAHs and dioxins/furans, exposure
from direct inhalation of the chemical can be much less than exposure from ingestion of the
chemical in water, fish, and food products grown in an area of chemical deposition. Vegetables
and fruits in such areas can become contaminated directly by deposition of the airborne chemical
to foliage, fruits, and vegetables or indirectly by root uptake of the chemical deposited to soils.
Livestock can be exposed to persistent and bioaccumulative chemicals via ingestion of
contaminated forage and incidental ingestion of contaminated soils.
For chemicals characterized as persistent and bioaccumulative, evaluation of the inhalation
pathway for air pollutants may reveal only a portion of the risk to individuals. Households that
consume high quantities of self-caught fish or locally grown produce and animal products may
be particularly susceptible to ingestion of chemicals transferred from air in the vicinity of an air
emissions source. For persistent and bioaccumulative chemicals in particular, therefore, USEPA
developed methods of estimating indirect exposure pathways associated with the deposition of
airborne chemicals to gardens and farms, as described in HHRAP (USEPA 2005a).
K.1.2. MIRC Highlights
MIRC is a flexible, stand-alone software application. A user can supply either measured or
estimated chemical concentrations for soil, air, water, and fish, and also can provide air
deposition rates likely for the location(s) of interest based on local meteorology. The user can
accept the default values for many exposure parameters and screen for small possibilities of risk,
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
or the user can select other options or overwrite parameter values to tailor the estimates to a
specific scenario or location.
MIRC complies with EPA's latest guidelines for exposure and risk assessment, including
HHRAP; the Agency's 2005 Guidelines for Carcinogen Risk Assessment (Cancer Guidelines),
Supplemental Guidance for Assessing Susceptibility from Early-Life Exposure to Carcinogens
(Supplemental Guidance), and Guidance on Selecting Age Groups for Monitoring and Assessing
Childhood Exposures to Environmental Contaminants (USEPA 2005b,c,d); and its Child-
Specific Exposure Factors Handbook (USEPA 2008a). In particular, MIRC provides several
important capabilities:
¦ When provided air and soil concentrations, the MIRC software package allows rapid calculation of screening-
level exposures and risks associated with household consumption of locally grown/raised foods.
¦ MIRC can calculate exposures and risks associated with incidental ingestion of surface soils, fish consumption,
and drinking water.
¦ The tool calculates ADDs (i.e., chemical intake rates) for six "built-in" age groups to allow use of age-group-
specific body weights, ingestion rates, food preferences, and susceptibility to toxic effects.
¦ Its database of chemical information covers plant- and animal-specific transfer factors and other inputs that
determine concentrations in farm food stuffs.
¦ Value options for receptor characteristics in the database include the mean and 50th, 90th, 95th, and 99th
percentile values where data permit. For assessment of carcass management options, mean values are used.
¦ For carcinogens with a mutagenic mode of action, MIRC estimates a lifetime (LADD) using the three lifestages
and potency adjustment factors recommended in USEPA's (2005c,d) cancer guidelines and supplemental
guidance.
¦ The data for children issued September 30, 2008, in the Agency's Child-Specific Exposure Factors Handbook
(CSEFH) (USEPA 2008a) are included in MIRC.
K„2, MIRC Overview
The MIRC software package allows rapid calculation of screening-level exposures and risks
associated with subsistence and recreational farmer/fisher populations in the vicinity of a source
of chemical emissions to air. The tool allows a user to assess human exposures via ingestion
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
pathways, including drinking water consumption, incidental soil ingestion, fish ingestion, and
ingestion of ten types of farm-grown food products: exposed fruits, protected fruits, exposed
vegetables, protected vegetables, root vegetables, beef, total dairy, pork, poultry, and eggs. The
tool also includes a breast milk ingestion and risk module for nursing infants, though we do not
use this module in this exposure assessment of livestock carcass management options. For fruits
and vegetables, the terms "exposed" and "protected" refer to whether the edible portion of the
plant is exposed to the atmosphere.
K.2.1. Exposure Pathways
MIRC estimates the concentrations of chemicals in the farm food categories grown in an area of
airborne chemical deposition using algorithms and parameter values provided in HHRAP
(USEPA 2005a). Further details about the HHRAP algorithms and default assumptions are
available in the HHRAP documentation (USEPA 2005a).
MIRC includes ten categories of food: exposed fruit, protected fruit, exposed
vegetables, protected vegetables, root vegetables, beef, total dairy, pork, poultry, and eggs.
Table K. 1 summarizes the pathways by which chemicals are transferred to these foods.
Plant produce included in MIRC can accumulate a chemical directly from air and/or soil. For
exposed produce, chemical mass is assumed to be transferred to plants from the air in two ways.
First, particle-bound chemical can deposit directly on the plant surface. Second, the uptake of
vapor-phase chemicals by plants through their foliage can occur. For both exposed and protected
produce, the concentration in the plant derived from exposure to the chemical in soil is estimated
using an empirical bioconcentration factor that relates the concentration in the plant to the
concentration present in the soil. For belowground root vegetables, a root concentration factor is
applied. We list the algorithms used to estimate produce concentrations in Section K.3.1 of this
appendix.
Chemical concentrations in animal products are estimated based on the amount of chemical
consumed through the diet, including incidental ingestion of soil while grazing. The diet options
for farm animals in MIRC include forage (plants grown on-site for animal grazing, such as
grass), silage (wet forage grasses, fresh-cut hay, or other fresh plant material that has been stored
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
and fermented), and feed grain products grown on the farm (e.g., corn, soybeans). All three
animal feed products are assumed to accumulate chemical via root uptake from the soil. Forage
and silage also can accumulate chemical via direct deposition of particle-bound chemical and
vapor transfer.
The algorithms in MIRC rely on the assumptions that beef and dairy cattle consume all three
feed products, while pigs consume only silage and grain, and chickens consume only grain from
the ground, and incidentally ingest contaminated surface soils. The incidental ingestion of the
chemical in soils during grazing or consumption of foods placed on the ground is estimated using
empirical soil ingestion values. For secondary animal products (dairy products and eggs), MIRC
estimates chemical concentrations by applying a biotransfer factor to the estimated concentration
in the "source" animal (cows and chickens, respectively). Section K.3.1 lists algorithms for
estimating animal product concentrations.
Table K.l. Transfer Pathways for the Modeled Farm-grown Foods.
Farm Food Media
Chemical Transfer Pathways
Exposed fruit and vegetables
• Direct deposition from air of particle-bound chemical
• Air-to-plant transfer of vapor phase chemical
• Root uptake from soil
Protected fruit and vegetables
(including root vegetables)
• Root uptake from soil
Beef and total dairy
(including milk)
• Ingestion of forage, silage, and grain3
• Soil ingestion
Pork
• Ingestion of silage and grain3
• Soil ingestion
Poultry and eggs
• Ingestion of grain3
• Soil ingestion
a Chemical concentrations in forage, silage, and grain are estimated via intermediate calculations analogous to those used for
aboveground produce.
K.2.2. Receptor Groups
As noted in USEPA risk assessment guidelines (USEPA 2005b,c,d, 2008a), exposures of
children differ from exposures of adults due to differences in body weights, ingestion rates,
dietary preferences, and other factors. It is important, therefore, to evaluate the contribution of
exposures during childhood to total lifetime risk using appropriate exposure factor values.
USEPA's HHRAP (Chapter 4, USEPA 2005a) recommends assessing exposures for children and
adults separately, but considers all non-infant children in one category. Specifically, HHRAP
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
recommends eight categories of receptor: farmer, child farmer, resident, child resident, fisher,
child fisher, acute receptor, and nursing infant. Over time, different USEPA programs have used
different child age groupings to evaluate body weights, ingestion rates, and other parameter
values needed to estimate chemical exposures and risks to children.
To improve the match between age groups used to estimate values across exposure parameters,
in 2005, USEPA recommended a standard set of child age categories for exposure and risk
assessments (USEPA 2005b). USEPA recommended four age groups for infants: birth to < 1
month; 1 to < 3 months; 3 to < 6 months; and 6 to < 12 months. For young children, USEPA
recommended an additional four age groups: 1 to < 2 years; 2 to < 3 years; 3 to < 6 years; and 6
to <11 years. Two age groupings are recommended for teenagers and young adults: 11 to < 16
years; and 16 to < 21 years. These age groupings correspond to different developmental stages,
and reflect different food ingestion rates per unit body weight, with the highest ingestion rates
occurring for the youngest, most rapidly growing, age groups.
Although the age groupings in MIRC do not precisely match the groupings USEPA
recommended in 2005 for Agency exposure assessments (USEPA 2005b), they are the only age-
groupings supported by available data. The 1987-1988 Nationwide Food Consumption Survey
(USDA 1992, 1993, 1994a) remains the most recent survey of ingestion rates for home-grown
foods, and USEPA's analysis of that data, published in its 2011 Exposure Factors Handbook,
remains the most recently published major analysis of the data. Because ingestion of home-
grown produce and animal products are the primary exposure pathways used to develop MIRC,
those are the age groupings we use for all child parameter values to estimate exposure and risk.
In this assessment, values for each exposure parameter are estimated for adults (20 to 70 years),
and five children's age groups:
¦ Infants under 1 year (i.e., 0 to < 1 year)
¦ Children ages 1 through 2 years (i.e., 1 to < 3 years)
¦ Children ages 3 through 5 years (i.e., 3 to < 6 years)
¦ Children ages 6 through 11 years (i.e., 6 to < 12 years)
¦ Children ages 12 through 19 years (i.e., 12 to < 20 years)
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
For assessment of cancer risks from early-life exposure, USEPA recognizes infants and children
may be more sensitive to a carcinogenic chemical than adults, with cancers appearing earlier in
life or with lower doses experienced during childhood (USEPA 2005c,d). For this reason, the
"potency" of a carcinogen might be higher for infants and children than for adults. To date,
however, data evaluating the relative sensitivity of children and adults to the same daily dose of a
carcinogen remains limited. Based on analyses of radioactive and other carcinogenic chemicals,
USEPA recommends evaluating two lifestages for children separately from adults for chemicals
that cause cancer by a mutagenic mode of action (MOA): from birth to < 2 years and from 2 to <
16 years (USEPA 2005c,d). USEPA also suggests that, as data become available regarding
carcinogens with a mutagenic MO A, further refinements of these age groupings may be
considered.
For assessing risks from exposures to carcinogenic chemicals that act via a mutagenic MO A,
USEPA recommends two early lifestages (USEPA 2005c,d) which are included in MIRC:
¦ Children under the age of 2 years (i.e., 0 to < 2 years)
¦ Children from 2 through 15 years (i.e., 2 to < 16 years)
Different age groupings are needed for the assessment of risks from carcinogenic chemicals with
a mutagenic MOA and other carcinogens with other or unknown MO As. Currently in MIRC, the
only persistent and bioaccumulative chemicals with a mutagenic mode of carcinogenesis would
be the carcinogenic PAHs. Arsenic also is persistent and carcinogenic via oral exposures.
K.3. Exposure Algorithms
The exposure algorithms in MIRC are described below in four sections. Section K.3.1 presents
the algorithms used to estimate chemical concentrations in farm-grown foods from chemical
concentrations in soil and air. We include both pathway-specific algorithms for estimating
chemical intake by adults and non-infant children. As noted previously, MIRC's exposure
algorithms are based on HHRAP modeling (USEPA 2005b). The explicit form of each algorithm
is in the HHRAP documentation. This section explains differences between MIRC and HHRAP.
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
K.3.1. Farm-Raised Foods - Algorithms to Calculate Chemical
Concentrations
MIRC's algorithms separately evaluate the chemical concentrations that accrue in produce from
those in animal products. The following subsections describe the algorithms and parameters used
for each of these estimation processes. The applicable modeled pathways correspond to specific
features exhibited by the growth of produce and animals.
Estimating Chemical Concentrations in Produce
Produce (vegetables and fruits) can be contaminated either directly by deposition of airborne
chemicals to foliage and fruits, or indirectly by uptake of chemicals deposited to the soil that
dissolve in the water that the plant absorbs for growth. Given these two contamination processes,
produce is divided into two main groups: aboveground and belowground produce. Aboveground
produce is divided into fruits and vegetables. These groups are further subdivided into "exposed"
and "protected" depending on whether the edible portion of the plant is exposed to the
atmosphere or is protected by a husk, hull, or other outer covering.
Table K.2 lists the transfer pathways for chemicals to the farm produce categories. The
subsections below describe the transfer pathways and algorithms for aboveground and
belowground produce, respectively.
Table K.2. Chemical Transfer Pathways for Produce.
Farm Food Media
Chemical Transfer Pathways
Aboveground Produce
Exposed fruits and vegetables
Direct deposition from air of particle-bound
chemical
Air-to-plant transfer of vapor phase chemical
Root uptake
Protected fruits and vegetables
Root uptake
Belowground Produce
Root vegetables
Root uptake
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Aboveground produce.
For aboveground exposed produce,
MIRC assumes chemical mass can be
transferred to plants from the air in three
ways, as illustrated in Figure K. 1. First,
particle-bound chemical can deposit
directly on the plant surface via
deposition (Pd). The amount of chemical
accumulated is estimated based on the
areal fraction of chemical deposition
intercepted by the plant surface, minus a
loss factor that is intended to account for
removal of deposited chemical by wind
¦ ¦ ¦«
^ v ^
SAfin
m f J
j.
t
Deposition
of Particles
(Pd)
Vapor
Transfer
(Pv)
Root Uptake
from Soil
(PfAG-produce)
Chemical Concentration in
Aboveground Produce
Figure K.1. Estimating chemical concentration
in aboveground produce.
and rain and changes in concentration due to growth dilution. Second, for chemical present in air
in the vapor phase, the concentration of chemical accumulated by the plant's foliage is estimated
using an empirical air-to-plant vapor biotransfer factor (Pv). Third, estimations of the chemical
concentration in the plant due to uptake by roots (PrAG-produce) uses an empirical
bioconcentration factor (BrAG-produce) that relates the chemical concentration in the plant to
the average chemical concentration in the soil at the root-zone depth in the produce-growing area
(Csroot-zone produce).
The edible portions of aboveground protected produce are not subject to contamination via
particle deposition (Pd) or vapor transfer (Pv). Therefore, root uptake of chemicals is the primary
mechanism through which aboveground protected produce becomes contaminated. As shown
below, the estimations of chemical concentration in the aboveground plant due to root uptake
(PrAG-produce-DW) use an empirical bioconcentration factor (BrAG-produce-DW) that relates
the chemical concentration in the plant to the average chemical concentration in the soil at the
root-zone depth in the produce-growing area (Csroot-zone_produce). All of these equations are
based on dry-weight (dw or DW) measurements.
Equation for Chemical Concentration in Aboveground Produce Due to Deposition of Particle-
phase Chemical. The equation in MIRC for chemical concentration in above ground produce
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
due to deposition of particle phase chemicals (Equation K.l) differs from Equation 5-14 in
HHRAP. In HHRAP, Equation 5-14 includes the term Qx( 1 -Fv) to indicate the emissions rate,
in g/sec, of chemicals from the source and the proportion of the chemical that remains in, or
partitions to, the particle-phase in the air. Also in HHRAP, the dry and wet particle phase
deposition rates, Dydp and Dywp, respectively, are normalized to the emission rate and are
expressed in units of sec/m2-yr.
In contrast, with MIRC, the user inputs both the dry and wet particle-phase deposition rates,
Drdp and Drwp, respectively, in units of g/m2-yr for a specific location relative to an emissions
source. Those deposition rates might be values measured near that location or estimated using a
fate and transport model, such as AERMOD, in conjunction with local meteorological
information and emissions rate data. The chemical emissions term used in HHRAP, Q, therefore,
is not used in MIRC's Equation K.l. In addition, in MIRC, Drdp and Drwp, the average annual
dry- and wet-particle-phase deposition rates, respectively, are in units of g/m2-yr whereas air
deposition from combustion-based carcass management scenarios occurs only over 48 hours,
requiring a conversion to a fraction of a year (i.e., 2/365 days = 0.00548 years). Moreover, the
wet deposition terms have limited effect, because we selected meteorological data on days with
negligible precipitation, assuming that open burning could not be conducted during periods of
rain.
where:
_ 1,000 x (Drdp + (Fw x Drwp)) x Rp{i) x (1 - e(-kp(iyTp(i))
Pd/:\ =
(')
(Eqn.K.1)
ypo) x kP(o
Pd(i) = Chemical concentration in aboveground produce type i on a dry-weight
(dw) basis due to particle deposition (mg/kg produce dw); set equal to
zero for protected aboveground produce
Drdp = Average annual dry deposition of particle-phase chemical (g/m2-yr)
Fw = Fraction of wet deposition that adheres to plant surfaces; 0.2 for anions,
0.6 for cations and most organics (unitless)
Drwp = Average annual wet deposition of particle-phase chemical (g/m2-yr)
Rpfi) = Interception fraction of the edible portion of plant type i (unitless)
kpm = Plant surface loss coefficient for plant type i (yr"')
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Tp(i) = Length of exposure to deposition in the field per harvest of the edible
portion of plant type i (yr)
Yp(i) = Yield or standing crop biomass of the edible portion of plant type i (kg
produce dw/m2)
Chemical Concentration in Aboveground Produce Due to Air-to-Plant Transfer of Vapor-
phase Chemical. Equation K.2 presents the equation used to estimate the transfer of vapor-phase
chemical to aboveground produce.
Dw _ Ca x Fv x Bvag(/) x VGag(,¦)
(/)" o
Pa (Eqn. K.2)
Concentration of chemical in edible portion of aboveground produce
type i from air-to-plant transfer of vapor-phase chemical on a dry-
weight (DW) basis ((J,g/g produce DW); set equal to zero for protected
aboveground produce
Average annual total chemical concentration in air (g/m3)
Fraction of airborne chemical in vapor phase (unitless)
Air-to-plant biotransfer factor for aboveground produce type i for vapor-
phase chemical in air ([mg/g produce DW] / [mg/g air], i.e., g air/ g
produce DW)
Empirical correction factor for aboveground exposed produce type i to
address possible overestimate of the diffusive transfer of chemical from
the outside to the inside of bulky produce, such as fruit (unitless)
Density of air (g/m3)
Belowgroundproduce. The equations by which MIRC estimates chemical concentrations in
belowground produce are different for nonionic organic chemicals than for inorganic chemicals
and ionic organic chemicals.
Nonionic organic chemicals. Soil covers belowground produce, such as tubers or root
vegetables, providing protection from chemical deposition and vapor transfer from air. Chemical
uptake through the roots is the primary mechanism for chemical contamination of belowground
produce. MIRC derives the nonionic organic chemical concentration in the tuber or root
vegetable from exposure to the chemical in soil. The algorithm uses an empirical root
concentration factor (RCF) and the average chemical concentration in the soil at the root-zone
where:
Pvfi)
Ca
Fv
BvAG(i)
VGag(i) =
Pa
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
depth in the produce-growing area (Csroot-zone_produce). The RCF relates the chemical
concentration in the plant on a wet-weight basis to the average chemical concentration in the
root-zone soil (Csroot-zoneproduce) on a dry-weight basis.
The RCF, as developed by Briggs et al. (1982), is the ratio of the chemical concentration in the
edible root on a wet-weight (ww) basis to its concentration in the soil pore water. RCFs are based
on experiments with growth solutions (hydroponic) instead of soils making it necessary to divide
the soil concentration by the chemical-specific soil/water partition coefficient (Kds) to accurately
model a soil-based crop production system. There is no conversion of chemical concentrations in
belowground produce from dw to ww because the values are already on a ww basis.
For nonionic organic chemicals, it is possible to predict RCF values and Kds values (for a
specified soil organic carbon content) from an estimate of the chemical's Kow from empirically
derived regression models. Those models are shown in HHRAP Appendix A-2, Equations
A-2-14 and A-2-15 (RCF) and in Equations A-29 and A-2-10 (Kds). The RCF and Kd values
calculated for many of the chemicals in HHRAP already are included in the MIRC database
(including the values for PAHs and dioxins).
Inorganic and ionic organic chemicals. For inorganic chemicals and ionized organic chemicals,
it is not possible to predict RCF or Kds values from Kow. Instead, inorganic chemical
calculations use chemical-specific empirical values for the root/soil bioconcentration factor. The
root/soil bioconcentration factor, now specified as BrBG-produce-DW., must be obtained from
the literature for each inorganic chemical on a dw basis.
Estimating Chemical Concentrations in Animal Products
MIRC estimates chemical concentrations in animal products from the amount of chemical
consumed by each animal group (designated m) through each plant feed type (designated z) or
(PlantCh-Intake(i,m)) combined with the incidental ingestion of soil for ground-foraging animals
(,SoilCh-Intake(m)). Table K.3 summarizes the transfer pathways for chemicals to these home- or
farm-raised animal food products. Note that for a general screening-level assessment, all of the
pathways can be modeled, as is done for USEPA's Risk and Technology Review calculation of
screening threshold emission rates for persistent and bioaccumulative chemicals that are also
listed as hazardous air pollutants (USEPA 2008b).
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
The feed options for farm animals in MIRC include forage (plants grown on-site for animal
grazing, such as grass), silage (wet forage grasses, fresh-cut hay, or other fresh plant material
that has been stored and fermented), and grain products grown on the farm. The algorithms for
chemical intake with plant feeds (PlcmtCh-Intcike(i,m)) are based on the assumptions that beef
and dairy cattle consume all three plant feed products, while pigs consume only silage and grain,
and chickens consume only grain.
Table K.3. Chemical Transfer Pathways for Animal Products.
Farm Food Media Chemical Transfer Pathways
Animal Products
Beef and total dairy (including
• Ingestion of forage, silage, and grain3
milk)
• Incidental soil ingestion
Pork
• Ingestion of silage and grain3
• Incidental soil ingestion
Poultry and eggs
• Ingestion of grain3
• Incidental soil ingestion
a Chemical concentrations in plant feed (i.e., forage, silage, and grain) are estimated via intermediate calculations.
MIRC assumes three types of plant tissue exposures ultimately can affect animals. As the plants
grow, all three types of animal feed accumulate chemicals via root uptake. In addition, there is
exposure of forage and silage plant tissues to the air, so those animal foods can accumulate
chemicals via direct deposition of particle-bound chemicals and transfer of vapor-phase
chemicals. The plants that produce animal feed grains are protected from the air by a husk or pod
(e.g., corn, soybeans), so the model does not include direct deposition and vapor-phase transfers
from air to these feeds.
Estimation of chemical concentrations in animal feeds uses algorithms analogous to those for
aboveground farm produce, as described above. To account for endogenous degradation of a
chemical within an animal, MIRC adjusts the chemical concentration in mammalian farm
animals (i.e., beef and pigs) using a metabolism factor (MF). The MF is set to 1.0 for chemicals
that are not metabolized (e.g., metals) and for chemicals with an unknown metabolic degradation
rate (e.g., PAHs). Although other vertebrates, including birds, are likely to use similar metabolic
pathways for most chemicals, MIRC adopts a health protective assumption that birds do not
metabolize any chemicals and omits an MF from the calculations for poultry and eggs.
MIRC estimates incidental ingestion of soil containing chemicals by livestock during grazing or
consumption of feed placed on the ground (SoilCh-Intake(m)) using empirical soil ingestion rates
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
(Qs) and a soil bioavailability factor for livestock (Bs). The default value for Bs for all chemicals
is 1.0, which means there is 100% bioavailability of the chemical to the animal. This assumption
might be reasonably accurate for the soil surfaces receiving deposition of an airborne chemical.
MIRC allows the user to enter a surface soil concentration for areas where livestock forage as
CsS-live stock.
MIRC calculates animal ingestion of chemicals in feed for each type of livestock (designated m
in the modeling) based on the composition of foodstuff in their diet. The type of feed is
designated / in the modeling. For beef and dairy cattle, estimates of chemical intake use all three
feed types forage, silage, and grain. For pork, estimates of the chemical intake use only silage
and grain. For poultry, estimates of the chemical intake are based on grain consumption. The
intake of chemical with each feed type, PlantCh-Intake(i,m), is calculated separately. Note that
the animal feed ingestion rates are on a dry-weight (dw) basis; consequently, there are no dw to
wet weight (ww) conversions. In addition, incidental ingestion of contaminated soils is included
for consumption of forage by cattle and of grains by chickens.
The concentrations of chemicals in the three different types of plant feeds for livestock are
calculated in the same way as aboveground produce with two exceptions. The concentrations are
for plants used as animal feeds (not produce consumed by humans), and all types of plant feed
(i.e., forage, silage, and grain) are aboveground.
MIRC calculates the chemical concentration in animal feed from uptake through the roots in the
same way as it does for uptake of chemicals from plants for human consumption with two
exceptions. First, the modeling uses a Br value appropriate to grasses. Secondly, MIRC allows
different soil concentrations for the chemical in the area growing the animal feed than in the area
growing produce for human consumption, if appropriate (e.g., in spatially explicit models). Note
that for grains, the Pd and Pv terms do not apply, and the values are set to zero, because the feed
products (i.e., corn kernels, soy beans) are protected from the air by husks or pods.
The algorithms used to calculate Pd and Pv for forage and silage are identical to those used to
calculate the same parameters for aboveground exposed produce.
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
K.3.2. Chemical. Intake Calculations for Adults and Non-Infant Children
MIRC calculates human chemical intake rates from the ingestion of home-grown foods as
average daily doses (ADDs) normalized to body weight. MIRC separately calculates ADDs for
each chemical, home-grown food type, and consumer age group. ADDs are expressed in
milligrams of chemical per kilogram of receptor body weight per day (mg/kg-day). Calculation
of ADDs takes into account six major factors. They are: (1) the chemical concentration in each
food type i (or in water), (2) the quantity of food brought into the home for consumption, (3) the
loss of some of the mass of the foods due to preparation and cooking, (4) how much of the food
is consumed per year, (5) the amount of the food obtained from contaminated areas, and (6) the
consumer's body weight (USEPA 2011, 2003a).
MIRC evaluates only one exposure scenario at a time. For screening-level assessments, it
assumes all components of this equation remain constant for consumers in a given age group
over time (e.g., seasonal and annual variations in diet are not explicitly taken into account). To
calculate an ADD(y,i) from the contaminated area for food group i over an entire lifetime of
exposure, age-group-specific ingestion rates and body weights are used for the age groups
described in the main section. In MIRC, the averaging time used to calculate the daily dose for
an age group (A Ty) equals the exposure duration for that group (EDy); therefore these variables
cancel out and therefore do not affect the calculations.
For each chemical included in a screening scenario, MIRC estimates the total average daily
exposure for age groups (ADD(y)) as the sum of chemical intake from all ingestion pathways:
¦ Incidental soil ingestion
¦ Ingestion of fish
¦ Ingestion of homegrown fruits (exposed and protected)
¦ Ingestion of homegrown vegetables (exposed, protected, and root)
¦ Ingestion of animal products from home-raised animals:
• milk and other dairy products from cows
• beef products
• pork products
• poultry and eggs
¦ Ingestion of drinking water as formula from a farm source (infants only)
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
HHRAP documentation describes the algorithms for the six exposure pathways listed above.
This assessment briefly describes pertinent features for five of these exposure pathways.
First, a possible exposure pathway in MIRC is ingestion of locally caught fish that are potentially
contaminated with chemicals from the carcass management option. USEPA estimates the
proportion of the weight of whole fish that tends to be lost during preparation and cooking across
a variety of fish species (USEPA 2011), and includes those losses in its HHRAP algorithms for
chemical intake from fish. Preparation of whole fish for cooking usually involves removal of the
viscera, head, and fins, particularly for larger fish. Many persons also remove (or do not eat) the
skin, bones, and belly fat. There are two types of fish included in the exposure algorithm: trophic
level 3.5 (abbreviated as TL3) fish, equivalent to benthic carnivores such as catfish, and trophic
level 4 (TL4) fish in the water column, equivalent to game fish such as lake trout and walleye.
The equations for each trophic level includes corrections for the relative loss during preparation
and cooking.
Second, a possible exposure pathway in MIRC is the ingestion of fruit potentially contaminated
with chemicals from the carcass management option. MIRC separately calculates ADDs of a
chemical from homegrown exposed and protected fruit. MIRC bases fruit ingestion rates on
weights of unprepared fruits (e.g., one apple; one pear) or the weight of a can of fruit (e.g., 8
ounce can). The weight of ingested fruit often is less than the initial weight owing to common
preparation actions, such as coring or peeling apples and pears or pitting cherries (LlExpFruit
and LlProFruit). Cooking of exposed fruit (e.g., berries, apples, peaches) reduces the liquid
content so the weight of the cooked fruit is less than the initial weight (L2ExpFruit). USEPA
assumes cooking of protected fruit does not reduce the weight of the fruit.
Third, MIRC includes three separate algorithms for homegrown vegetables (exposed, protected,
and root). Examples of exposed vegetables are asparagus, broccoli, lettuce, and tomatoes
(although they are actually a fruit). Protected vegetables include corn, cabbage, soybeans, and
peas. Root vegetables are carrots, beets, and potatoes.
Fourth, the effect of cooking on animal products may alter the concentration of chemicals in the
food product as consumed. The reduction in the weight of beef, pork, and poultry during and
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
after cooking (so called "shrinkage") might cause an increase or decrease in the concentration of
the chemical in the consumed food depending on the chemical and the cooking method.
Last, MIRC models the potential for chemical ingestion by infants through contaminated
drinking water used to dilute formula. MIRC allows users to specify a chemical concentration in
g/L (equivalent to mg/mL) pertinent to their particular scenario. The chemical concentration
could represent water from groundwater wells, community water, nearby surface waters, or other
source. For this exposure pathway, ingestion rates are in units of milliliters of water per day
(mL/day).
K.3.3. Calculation of Total Chemical. Intake
To estimate the total ADD, or intake of a chemical from all of the exposures that a single
individual in each age group might contact (e.g., soil, local fish, five types of home-grown
produce, and five types of home-raised animals or animal products), the media-specific chemical
intakes are summed for each age group. MIRC estimates the total average daily exposure for a
particular age groups (ADD(y)) as the sum of chemical intake from all ingestion pathways.
K.4. Model Input Options
This section describes the MIRC input options. Section K.4.1 describes the required user inputs
for environmental media concentrations and air deposition rates. Section K.4.2 discusses
parameter values for specific types of produce and animal products. Next, section K.4.3
describes options for parameterizing receptor characteristics including age-group-specific values
for body weight, water ingestion, and food ingestion by food type. Finally, section K.4.4
discusses options for other exposure parameter values in MIRC, such as exposure frequency and
loss of chemical during food preparation and cooking.
The MIRC database contains chemical-specific parameter values for more than 500 chemicals
derived from all of the chemical-specific input data compiled by USEPA for use in HHRAP.
This assessment considers only those chemicals that are persistent and/or bioaccumulative and
toxic (e.g., 2,3,7,8 dioxins/furans, medium and heavier weight PAHs, heavy metals) that are
evaluated for USEPA's Risk and Technology Review. The HHRAP inputs provided for other
chemicals were not reviewed or verified.
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
K.4.1. Environmental Concentrations
As noted in Section K.2 of these appendices, MIRC estimates exposures and risks to self-
sufficient farming and fishing families from ingestion of farm-grown produce in an area
receiving airborne chemical deposition. The tool analyzes one exposure scenario at a time, such
as an adult farmer exposed to dioxin from ingestion of beef. For this reason, MIRC's analysis is
the most robust when evaluating a maximally exposed individual (MEI) or family when
screening for possible risks.
The following values specific to the air pollutant of concern are required inputs to MIRC:
¦ A single air concentration (in g/m3)
¦ The fraction of chemical in the air that is in the vapor phase
¦ Air-to-surface deposition rates for both vapor- and particle-phase chemical in the air (in g/m2-yr)
¦ Two fish tissue concentrations, one each for forage and game fish (i.e., fish in TL3 and TL4) (in mg/kg wet
weight)
¦ Concentrations in drinking water (in g/L)
¦ Four chemical concentrations in soil (in \xg/g dry weight), one each for:
• surface soil in produce growing area
• surface soil where livestock feed
• root-zone soil in produce growing area
• root-zone soil in livestock feed growing
The MIRC software configuration estimates ingestion exposures via drinking water for a
specified chemical concentration in the drinking water source (e.g., groundwater well).
The user must provide the inputs listed above; there are no default values for these parameters in
MIRC. For this livestock carcass exposure assessment, we computed these inputs using
AERMOD (for air concentrations and deposition rates), the SSW model, AQUAWEB (for fish
concentrations), and other calculation methods described in Section 4 of the main report. A
Microsoft® Excel™ routine in Visual Basic facilitated the aggregation of these inputs from the
various tools, and organized them for use by MIRC.
K.4.2. Chemical. Uptal iriii Food Products
Using the above identified chemical information as inputs, MIRC calculates chemical
concentrations in foods that are commonly grown or raised on family farms using algorithms
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
from HHRAP (USEPA 2005a). Parameter values required for these HHRAP algorithms,
including chemical-specific media transfer factors (e.g., soil-to-plant transfer coefficients) and
plant- and animal-specific properties (e.g., plant interception fraction, quantity of forage
consumed by cattle), are in tables in MIRC. The HHRAP-recommended parameter values are the
default values in MIRC; however, these and other inputs in MIRC can be revised or overwritten
as needed. Table K.4 describes the parameters that are included in the algorithms used to
estimate chemical concentrations in the farm food categories. The parameter names and symbols
are referenced in this section for plants/produce and animal products.
Table K.4. MIRC Parameters Used to Estimate Chemical Concentrations in Farm Foods.
Parameter
Description
Units
Plants/Produce
Br AG-
produce-DW(i)
Chemical-specific plant/soil chemical bioconcentration factor for
edible portion of aboveground produce type exposed or protected
Unitless (g soil dw / g
produce dw)
Bv AG(i)
Chemical-specific air-to-plant biotransfer factor for aboveground
produce type i for vapor-phase chemical in air
Unitless ([mg chemical /
g plant dw] / [mg
chemical / g air])
Fw
Fraction of wet deposition that adheres to plant surfaces; 0.2 for
anions, 0.6 for cations and most organics
Unitless
Kds
Chemical-specific soil/water partition coefficient
L soil pore water / kg
soil dw
kpji)
Plant-specific surface loss coefficient for aboveground exposed
produce and animal forage and silage
yr1
MAFJi)
Moisture adjustment factor for aboveground produce type i to convert
the chemical concentration estimated for dry-weight produce to the
corresponding chemical concentration for full-weight fresh produce
Percent water
RCF
Chemical-specific root concentration factor for tubers and root
produce on a wet-weight (ww) basis
L soil pore water/ kg
root ww
Rpji)
Plant-specific interception fraction for the edible portion of
aboveground exposed produce or animal forage and silage
Unitless
Tpjf)
Length of plant exposure to deposition per harvest of the edible
portion of aboveground exposed produce or animal forage and silage
Year
I'd . I( i(/)
Empirical correction factor for aboveground exposed produce type i
to address possible overestimate of the diffusive transfer of chemical
from the outside to the inside of bulky produce, such as fruit
Unitless
J'G root\'eg
Empirical correction factor for belowground produce (i.e., tuber or
root vegetable) to account for possible overestimate of the diffusive
transfer of chemicals from the outside to the inside of bulky tubers or
roots (based on carrots and potatoes)
Unitless
YpJJ)
Plant-specific yield or standing crop biomass of the edible portion of
produce or animal feed
kg produce dw/m2
Animal Products
Bs
Soil bioavailability factor for livestock
Unitless
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Parameter
Description
Units
MF
Chemical-specific mammalian metabolism factor that accounts for
endogenous degradation of the chemical
Unitless
Ba (beef)
Chemical-specific biotransfer factor for chemical in diet of cow to
chemical in beef on a fresh-wet (fw; equivalent to ww) basis
mg chemical/kg tissue
fw/mg chemical/day or
day/kg fw tissue
Ba (dairy)
Biotransfer factor in dairy
day/kg tissue fw
Ba (pork)
Biotransfer factor in pork
day/kg tissue fw
Ba (poultry)
Biotransfer factor in poultry
day/kg tissue fw
Bajeggs)
Biotransfer factor in eggs
day/kg tissue fw
Os_(m)
Quantity of soil eaten by animal type m each day
kg/day
Op_(i,m)
Quantity of plant feed type i consumed per animal type m each day
kg/day
Abbreviations: dw = dry weight; fw = fresh weight = ww = wet weight; L = liter; yr = years.
Note: Underline means that the following text should be subscripted; however, subscripting in this table would
be too small to be legible.
Source: USEPA 2005a.
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Table K.5 and Table K.6 provide the chemical-specific input values that are the current defaults
for produce FFC food types in MIRC.
Table K.5. Chemical-Specific Inputs for Produce Parameters for Chemicals Included in
MIRC.
Fraction of Wet
Root
Concentration
Soil Water
Partition
Chemical Air to
Plant Biotransfer
Factor (/ivicvw)
(unitless)d
Chemical
Deposition (F\v)
(unitless)8
Factor (RCF)
(belowground)
(L/kg)b
Coefficient
(Kds)
(L/kg)c
Inorganics
Cadmium compounds
0.6
na
7.5E+01
nae
Mercury (elemental)
0.6
na
1.0E+03
0f
Mercuric chloride
0.6
na
5.8E+04
1.8E+03
Methyl mercury
0.6
na
7.0E+03
0f
PAHs
2-Methylnaphthalene
0.6
2.2E+02
5.0E+01
1.4E+00
7,12-
Dimethylbenz[a]anthracene
0.6
6.8E+03
4.0E+03
4.2E+04
Acenaphthene
0.6
2.4E+02
3.9E+01
4.6E+00
Acenaphthylene
0.6
2.8E+02
6.8E+01
8.1E+00
Benz[a]anthracene
0.6
6.7E+03
2.9E+03
6.8E+03
Benzo[a]pyrene
0.6
9.2E+03
7.8E+03
1.7E+05
Benzo [b]fluoranthene
0.6
6.6E+03
3.8E+03
1.7E+05
Benzo [g,h,i]perylene
0.6
3.0E+04
2.6E+04
2.3E+06
Benzo [k] fluoranthene
0.6
8.7E+03
5.5E+03
2.8E+05
Chrysene
0.6
6.0E+03
3.4E+03
1.4E+04
Dibenz [a,h] anthracene
0.6
2.3E+04
1.4E+04
6.2E+06
Fluoranthene
0.6
2.2E+03
3.9E+02
9.0E+02
Fluorene
0.6
3.8E+02
6.2E+01
1.6E+01
Indeno [ 1,2,3 -cd]pyrene
0.6
3.5E+04
3.2E+04
2.8E+06
Dioxins
OctaCDD, 1,2,3,4,6,7,8,9-
0.6
4.8E+05
7.8E+05
2.4E+06
OctaCDF, 1,2,3,4,6,7,8,9-
0.6
3.4E+05
4.9E+05
2.3E+06
HeptaCDD, 1,2,3,4,6,7,8-
0.6
3.4E+05
4.9E+05
9.1E+05
HeptaCDF, 1,2,3,4,6,7,8-
0.6
1.2E+05
1.2E+05
8.3E+05
HeptaCDF, 1,2,3,4,7,8,9-
0.6
4.8E+04
3.9E+04
8.3E+05
HexaCDD, 1,2,3,4,7,8-
0.6
2.4E+05
3.1E+05
5.2E+05
HexaCDF, 1,2,3,4,7,8-
0.6
5.7E+04
4.9E+04
1.6E+05
HexaCDD, 1,2,3,6,7,8-
0.6
4.9E+05
8.0E+05
5.2E+05
HexaCDF, 1,2,3,6,7,8-
0.6
2.9E+05
4.1E+05
1.6E+05
HexaCDD, 1,2,3,7,8,9 -
0.6
4.9E+05
8.0E+05
5.2E+05
HexaCDF, 1,2,3,7,8,9-
0.6
1.6E+05
1.9E+05
1.6E+05
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Chemical
Fraction of Wet
Deposition (Fw)
(unitlcss)"
Root
Concentration
Factor (RCF)
(belowground)
(L/kg)b
Soil Water
Partition
Coefficient
(Kds)
(L/kg)c
Chemical Air to
Plant Biotransfer
Factor (/ivicvw)
(unitless)d
HexaCDF, 2,3,4,6,7,8-
0.6
2.9E+05
4.1E+05
1.6E+05
PentaCDD, 1,2,3,7,8-
0.6
9.2E+04
9.2E+04
2.4E+05
PentaCDF, 1,2,3,7,8-
0.6
3.9E+04
3.0E+04
9.8E+04
PentaCDF, 2,3,4,7,8-
0.6
2.3E+04
1.6E+04
9.8E+04
TetraCDD, 2,3,7,8-
0.6
4.0E+04
3.1E+04
6.6E+04
TetraCDF, 2,3,7,8-
0.6
1.2E+04
6.2E+03
4.6E+04
Abbreviations: na = not applicable.
Source: USEPA 2005a.
a 6E-01 is the value for cations and most organic chemicals. As described in HHRAP (USEPA 2005a), Appendix B (available at
http://www.epa.gov/osw/liazard/tsd/td/combust/finalmact/ssra/051ilirapapb.pdf). USEPA estimated this value (USEPA 1994a,
1995a) from a study by Hoffman et al. (1992) in which soluble gamma-emitting radionuclides and insoluble particles tagged with
gamma-emitting radionuclides were deposited onto pasture grass via simulated rain. Note that the values developed
experimentally for pasture grass may not accurately represent all aboveground produce-specific values. Also note that values
based on the behavior of insoluble particles tagged with radionuclides may not accurately represent the behavior of organic
compounds under site-specific conditions.
b For nonionic organic chemicals, as described in HHRAP (USEPA 2005a), Appendix A (available at
http://www.epa.gov/osw/liazard/tsd/td/conibust/finalniact/ssra/051ilirapapa.pdf). RCF is used to calculate the below-ground
transfer of contaminants from soil to a root vegetable on a wet-weight basis. Chemical-specific values for RCF from empirical
regression equations developed by Briggs et al. (1982) based on their experiments measuring uptake of compounds into barley
roots from growth solution. Briggs' regression equations allow calculation of RCF values from log Kow. For metals and mercuric
compounds, empirical values for soil to root vegetable transfer on a dry-weight basis are available in the literature, thus the RCF
was not needed.
c As discussed in F1HRAP (USEPA 2005a), Appendix A, Kds describes the partitioning of a compound between soil pore-water
and soil particles and strongly influences the release and movement of a compound into the subsurface soils and underlying
aquifer. Kds values for mercuric compounds were obtained from USEPA (1997b). Kds for cadmium compounds were obtained
from USEPA 1996. For all PAHs and dioxins, Kds was calculated by multiplying Koc times the screening scenario's fraction
organic carbon content (0.008). Empirical information for Koc was available for acenaphthene, benz[a]antliracene,
benzo[a]pyrene, dibenz[a,h]antliracene, fluoranthene, and fluorene in USEAP 1996. For all other organic compounds, the Koc
was calculated using the correlation equations presented in USEAP 2005a.
d As discussed in F1HRAP (USEPA 2005a), Appendix A, the value for mercuric chloride was obtained from USEPA 1997b.
Bv_AG(i) values for PAHs were calculated using the correlation equation derived for azalea leaves as cited in Bacci et al. (1992),
then reducing this value by a factor of 100, as suggested by Lorber (1995), who concluded that the Bacci factor reduced by a
factor of 100 was similar to his own observations in various studies. The values for dioxins were obtained from Lorber and
Pinsky (2000).
e It is assumed that metals, with the exception of vapor-phase elemental mercury, do not transfer significantly from air into
leaves.
f Speciation and fate and transport of mercury from emissions suggest that Bv_AG(i) values for elemental and methyl mercury are
likely to be zero (USEPA 2005a).
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Table K.6. Chemical-Specific Inputs by Plant Type for Chemicals in MIRC.
Plant Soil Bio
Concentration
Empirical Correction
Factor
Belowground Produce
(VGrootveg) (unitless)b
Empirical Correction
Factor
Compound Name
Plant Part
Factor
(BrAG produce DlV(i))
(unit less)11
Aboveground
Produce
(VGagw) (unitlcss)'
Inorganics
Exp. Fruit
1.3E-01
-
1.0E+00
Exp. Veg.
1.3E-01
-
1.0E+00
Forage
3.6E-01
-
1.0E+00
Cadmium compounds
Grain
6.2E-02
-
-
Prot. Fruit
1.3E-01
-
-
Prot. Veg.
1.3E-01
-
-
Root
6.4E-02
1.0E+00
-
Silage
3.6E-01
-
5.0E-01
Exp. Fruit
-
-
1.0E+00
Exp. Veg.
-
-
1.0E+00
Forage
-
-
1.0E+00
Mercury (elemental)
Grain
-
-
-
Prot. Fruit
-
-
-
Prot. Veg.
-
-
-
Root
-
1.0E+00
-
Silage
-
-
5.0E-01
Exp. Fruit
1.5E-02
-
1.0E+00
Exp. Veg.
1.5E-02
-
1.0E+00
Forage
0.0E+00
-
1.0E+00
Mercuric chloride
Grain
9.3E-03
-
-
Prot. Fruit
1.5E-02
-
-
Prot. Veg.
1.5E-02
-
-
Root
3.6E-02
1.0E+00
-
Silage
0.0E+00
-
5.0E-01
Exp. Fruit
2.9E-02
-
1.0E-02
Exp. Veg.
2.9E-02
-
1.0E-02
Forage
0.0E+00
-
1.0E+00
Methyl mercury
Grain
1.9E-02
-
-
Prot. Fruit
2.9E-02
-
-
Prot. Veg.
2.9E-02
-
-
Root
9.9E-02
1.0E-02
-
Silage
0.0E+00
-
5.0E-01
K-23
-------
Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Compound Name
Plant Part
Plant Soil Bio
Concentration
Factor
(BTAGproduce DW(i))
(unitlcss)11
Empirical Correction
Factor
Belowground Produce
(VGroob-eg) (unitless)b
Empirical Correction
Factor
Aboveground
Produce
(V(iu;(i)) (unitlcss)'
PAHs
Acenaphthene
Exp. Fruit
2.1E-01
-
1.0E+00
Exp. Veg.
2.1E-01
-
1.0E+00
Forage
2.1E-01
-
1.0E+00
Grain
2.1E-01
-
-
Prot. Fruit
2.1E-01
-
-
Prot. Veg.
2.1E-01
-
-
Root
6.2E+00
1.0E+00
-
Silage
2.1E-01
-
5.0E-01
Acenaphthylene
Exp. Fruit
1.9E-01
-
1.0E-02
Exp. Veg.
1.9E-01
-
1.0E-02
Forage
1.9E-01
-
1.0E+00
Grain
1.9E-01
-
-
Prot. Fruit
1.9E-01
-
-
Prot. Veg.
1.9E-01
-
-
Root
4.1E+00
1.0E-02
-
Silage
1.9E-01
-
5.0E-01
Benz[a]antliracene
Exp. Fruit
1.7E-02
-
1.0E-02
Exp. Veg.
1.7E-02
-
1.0E-02
Forage
1.7E-02
-
1.0E+00
Grain
1.7E-02
-
-
Prot. Fruit
1.7E-02
-
-
Prot. Veg.
1.7E-02
-
-
Root
2.3E+00
1.0E-02
-
Silage
1.7E-02
-
5.0E-01
Benzo[a]pyrene
Exp. Fruit
1.4E-02
-
1.0E-02
Exp. Veg.
1.4E-02
-
1.0E-02
Forage
1.4E-02
-
1.0E+00
Grain
1.4E-02
-
-
Prot. Fruit
1.4E-02
-
-
Prot. Veg.
1.4E-02
-
-
Root
1.2E+00
1.0E-02
-
Silage
1.4E-02
-
5.0E-01
Benzo [b]fluoranthene
Exp. Fruit
1.8E-02
-
1.0E-02
Exp. Veg.
1.8E-02
-
1.0E-02
Forage
1.8E-02
-
1.0E+00
Grain
1.8E-02
-
-
Prot. Fruit
1.8E-02
-
-
Prot. Veg.
1.8E-02
-
-
K-24
-------
Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Plant Soil Bio
Concentration
Empirical Correction
Factor
Belowground Produce
(VGroob-eg) (unitless)b
Empirical Correction
Factor
Compound Name
Plant Part
Factor
(BTAGproduce DW(i))
(unitlcss)11
Aboveground
Produce
(V(iu;(i)) (unitlcss)'
Root
1.7E+00
1.0E-02
-
Silage
1.8E-02
-
5.0E-01
Exp. Fruit
5.7E-03
-
1.0E-02
Exp. Veg.
5.7E-03
-
1.0E-02
Forage
5.7E-03
-
1.0E+00
Benzo(g,h,i)perylene
Grain
5.7E-03
-
-
Prot. Fruit
5.7E-03
-
-
Prot. Veg.
5.7E-03
-
-
Root
1.1E+00
1.0E-02
-
Silage
5.7E-03
-
5.0E-01
Exp. Fruit
1.4E-02
-
1.0E-02
Exp. Veg.
1.4E-02
-
1.0E-02
Forage
1.4E-02
-
1.0E+00
Benzo[k]fluoranthene
Grain
1.4E-02
-
-
Prot. Fruit
1.4E-02
-
-
Prot. Veg.
1.4E-02
-
-
Root
1.6E+00
1.0E-02
-
Silage
1.4E-02
-
5.0E-01
Exp. Fruit
1.9E-02
-
1.0E-02
Exp. Veg.
1.9E-02
-
1.0E-02
Forage
1.9E-02
-
1.0E+00
Chrysene
Grain
1.9E-02
-
-
Prot. Fruit
1.9E-02
-
-
Prot. Veg.
1.9E-02
-
-
Root
1.7E+00
1.0E-02
-
Silage
1.9E-02
-
5.0E-01
Exp. Fruit
6.8E-03
-
1.0E-02
Exp. Veg.
6.8E-03
-
1.0E-02
Forage
6.8E-03
-
1.0E+00
Dibenz(a,h)anthracene
Grain
6.8E-03
-
-
Prot. Fruit
6.8E-03
-
-
Prot. Veg.
6.8E-03
-
-
Root
1.6E+00
1.0E-02
-
Silage
6.8E-03
-
5.0E-01
Exp. Fruit
4.0E-02
-
1.0E-02
Exp. Veg.
4.0E-02
-
1.0E-02
Fluoranthene
Forage
4.0E-02
-
1.0E+00
Grain
4.0E-02
-
-
Prot. Fruit
4.0E-02
-
-
K-25
-------
Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Plant Soil Bio
Concentration
Empirical Correction
Factor
Belowground Produce
(VGroob-eg) (unitless)b
Empirical Correction
Factor
Compound Name
Plant Part
Factor
(BTAGproduce DW(i))
(unitlcss)11
Aboveground
Produce
(V(iu;(i)) (unitlcss)'
Prot. Veg.
4.0E-02
-
-
Root
5.6E+00
1.0E-02
-
Silage
4.0E-02
-
5.0E-01
Exp. Fruit
1.5E-01
-
1.0E-02
Exp. Veg.
1.5E-01
-
1.0E-02
Forage
1.5E-01
-
1.0E+00
Fluorene
Grain
1.5E-01
-
-
Prot. Fruit
1.5E-01
-
-
Prot. Veg.
1.5E-01
-
-
Root
6.2E+00
1.0E-02
-
Silage
1.5E-01
-
5.0E-01
Exp. Fruit
5.1E-03
-
1.0E-02
Exp. Veg.
5.1E-03
-
1.0E-02
Forage
5.1E-03
-
1.0E+00
Indeno( 1,2,3 -cd)pyrene
Grain
5.1E-03
-
-
Prot. Fruit
5.1E-03
-
-
Prot. Veg.
5.1E-03
-
-
Root
1.1E+00
1.0E-02
-
Silage
5.1E-03
-
5.0E-01
Dioxins
Exp. Fruit
7.1E-04
-
1.0E-02
Exp. Veg.
7.1E-04
-
1.0E-02
Forage
7.1E-04
-
1.0E+00
OctaCDD,
Grain
7.1E-04
-
-
1,2,3,4,6,7,8,9-
Prot. Fruit
7.1E-04
-
-
Prot. Veg.
7.1E-04
-
-
Root
6.1E-01
1.0E-02
-
Silage
7.1E-04
-
5.0E-01
Exp. Fruit
9.2E-04
-
1.0E-02
Exp. Veg.
9.2E-04
-
1.0E-02
Forage
9.2E-04
-
1.0E+00
OctaCDF,
Grain
9.2E-04
-
-
1,2,3,4,6,7,8,9-
Prot. Fruit
9.2E-04
-
-
Prot. Veg.
9.2E-04
-
-
Root
6.8E-01
1.0E-02
-
Silage
9.2E-04
-
5.0E-01
HeptaCDD,
1,2,3,4,6,7,8-
Exp. Fruit
9.2E-04
-
1.0E-02
Exp. Veg.
9.2E-04
-
1.0E-02
Forage
9.2E-04
-
1.0E+00
K-26
-------
Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Plant Soil Bio
Concentration
Empirical Correction
Factor
Belowground Produce
(VGroob-eg) (unitless)b
Empirical Correction
Factor
Compound Name
Plant Part
Factor
(BTAGproduce DW(i))
(unitlcss)11
Aboveground
Produce
(V(iu;(i)) (unitlcss)'
Grain
9.2E-04
-
-
Prot. Fruit
9.2E-04
-
-
Prot. Veg.
9.2E-04
-
-
Root
6.8E-01
1.0E-02
-
Silage
9.2E-04
-
5.0E-01
Exp. Fruit
2.0E-03
-
1.0E-02
Exp. Veg.
2.0E-03
-
1.0E-02
Forage
2.0E-03
-
1.0E+00
HeptaCDF,
Grain
2.0E-03
-
-
1,2,3,4,6,7,8-
Prot. Fruit
2.0E-03
-
-
Prot. Veg.
2.0E-03
-
-
Root
9.4E-01
1.0E-02
-
Silage
2.0E-03
-
5.0E-01
Exp. Fruit
4.0E-03
-
1.0E-02
Exp. Veg.
4.0E-03
-
1.0E-02
Forage
4.0E-03
-
1.0E+00
HeptaCDF,
Grain
4.0E-03
-
-
1,2,3,4,7,8,9-
Prot. Fruit
4.0E-03
-
-
Prot. Veg.
4.0E-03
-
-
Root
1.2E+00
1.0E-02
-
Silage
4.0E-03
-
5.0E-01
Exp. Fruit
1.2E-03
-
1.0E-02
Exp. Veg.
1.2E-03
-
1.0E-02
Forage
1.2E-03
-
1.0E+00
HexaCDD, 1,2,3,4,7,8-
Grain
1.2E-03
-
-
Prot. Fruit
1.2E-03
-
-
Prot. Veg.
1.2E-03
-
-
Root
7.6E-01
1.0E-02
-
Silage
1.2E-03
-
5.0E-01
Exp. Fruit
3.5E-03
-
1.0E-02
Exp. Veg.
3.5E-03
-
1.0E-02
Forage
3.5E-03
-
1.0E+00
HexaCDF, 1,2,3,4,7,8-
Grain
3.5E-03
-
-
Prot. Fruit
3.5E-03
-
-
Prot. Veg.
3.5E-03
-
-
Root
1.2E+00
1.0E-02
-
Silage
3.5E-03
-
5.0E-01
K-27
-------
Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Compound Name
Plant Part
Plant Soil Bio
Concentration
Factor
(BrAG produce DlV(i))
(unit less)11
Empirical Correction
Factor
Belowground Produce
(VGroob-eg) (unitless)b
Empirical
Correction Factor
Aboveground
Produce
(V(iu;(i)) (unitless)'
Exp. Fruit
7.0E-04
-
1.0E-02
Exp. Veg.
7.0E-04
-
1.0E-02
Forage
7.0E-04
-
1.0E+00
HexaCDD, 1,2,3,6,7,8-
Grain
7.0E-04
-
-
Prot. Fruit
7.0E-04
-
-
Prot. Veg.
7.0E-04
-
-
Root
6.1E-01
1.0E-02
-
Silage
7.0E-04
-
5.0E-01
Exp. Fruit
1.0E-03
-
1.0E-02
Exp. Veg.
1.0E-03
-
1.0E-02
Forage
1.0E-03
-
1.0E+00
HexaCDF, 1,2,3,6,7,8-
Grain
1.0E-03
-
-
Prot. Fruit
1.0E-03
-
-
Prot. Veg.
1.0E-03
-
-
Root
7.1E-01
1.0E-02
-
Silage
1.0E-03
-
5.0E-01
Exp. Fruit
7.0E-04
-
1.0E-02
Exp. Veg.
7.0E-04
-
1.0E-02
Forage
7.0E-04
-
1.0E+00
HexaCDD, 1,2,3,7,8,9-
Grain
7.0E-04
-
-
Prot. Fruit
7.0E-04
-
-
Prot. Veg.
7.0E-04
-
-
Root
6.1E-01
1.0E-02
-
Silage
7.0E-04
-
5.0E-01
Exp. Fruit
1.6E-03
-
1.0E-02
Exp. Veg.
1.6E-03
-
1.0E-02
Forage
1.6E-03
-
1.0E+00
HexaCDF, 1,2,3,7,8,9-
Grain
1.6E-03
-
-
Prot. Fruit
1.6E-03
-
-
Prot. Veg.
1.6E-03
-
-
Root
8.5E-01
1.0E-02
-
Silage
1.6E-03
-
5.0E-01
Exp. Fruit
1.0E-03
-
1.0E-02
Exp. Veg.
1.0E-03
-
1.0E-02
Forage
1.0E-03
-
1.0E+00
HexaCDF, 2,3,4,6,7,8-
Grain
1.0E-03
-
-
Prot. Fruit
1.0E-03
-
-
Prot. Veg.
1.0E-03
-
-
Root
7.1E-01
1.0E-02
-
K-28
-------
Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Compound Name
Plant Part
Plant Soil Bio
Concentration
Factor
(BrAG produce DlV(i))
(unit less)11
Empirical Correction
Factor
Belowground Produce
(VGroob-eg) (unitless)b
Empirical
Correction Factor
Aboveground
Produce
(V(iu;(i)) (unitlcss)'
Silage
1.0E-03
-
5.0E-01
Exp. Fruit
2.4E-03
-
1.0E-02
Exp. Veg.
2.4E-03
-
1.0E-02
Forage
2.4E-03
-
1.0E+00
PentaCDD, 1,2,3,7,8-
Grain
2.4E-03
-
-
Prot. Fruit
2.4E-03
-
-
Prot. Veg.
2.4E-03
-
-
Root
1.0E+00
1.0E-02
-
Silage
2.4E-03
-
5.0E-01
Exp. Fruit
4.6E-03
-
1.0E-02
Exp. Veg.
4.6E-03
-
1.0E-02
Forage
4.6E-03
-
1.0E+00
PentaCDF, 1,2,3,7,8-
Grain
4.6E-03
-
-
Prot. Fruit
4.6E-03
-
-
Prot. Veg.
4.6E-03
-
-
Root
1.3E+00
1.0E-02
-
Silage
4.6E-03
-
5.0E-01
Exp. Fruit
6.8E-03
-
1.0E-02
Exp. Veg.
6.8E-03
-
1.0E-02
Forage
6.8E-03
-
1.0E+00
PentaCDF, 2,3,4,7,8-
Grain
6.8E-03
-
-
Prot. Fruit
6.8E-03
-
-
Prot. Veg.
6.8E-03
-
-
Root
1.5E+00
1.0E-02
-
Silage
6.8E-03
-
5.0E-01
Exp. Fruit
4.5E-03
-
1.0E-02
Exp. Veg.
4.5E-03
-
1.0E-02
Forage
4.5E-03
-
1.0E+00
TetraCDD, 2,3,7,8-
Grain
4.5E-03
-
-
Prot. Fruit
4.5E-03
-
-
Prot. Veg.
4.5E-03
-
-
Root
1.3E+00
1.0E-02
-
Silage
4.5E-03
-
5.0E-01
Exp. Fruit
1.2E-02
-
1.0E-02
Exp. Veg.
1.2E-02
-
1.0E-02
TetraCDF, 2,3,7,8-
Forage
1.2E-02
-
1.0E+00
Grain
1.2E-02
-
-
Prot. Fruit
1.2E-02
-
-
Prot. Veg.
1.2E-02
-
-
K-29
-------
Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Compound Name
Plant Part
Plant Soil Bio
Concentration
Factor
(BrAG produce DlV(i))
(unit less)11
Empirical Correction
Factor
Belowground Produce
(VGroob-eg) (unitless)b
Empirical
Correction Factor
Aboveground
Produce
(V(iu;(i)) (unitlcss)'
Root
1.9E+00
1.0E-02
-
Silage
1.2E-02
-
5.0E-01
Abbreviations: = not required; prot. = protected; exp. = exposed.
a As discussed in HHRAP (USEPA 2005a), the Br^AG-produce-DW(i) for aboveground produce and forage accounts for the
uptake from soil and the subsequent transport of contaminants through the roots to the aboveground plant parts. For organics,
correlation equations to calculate values for Br on a dry weight basis were obtained from Travis and Anns (1988). For cadmium,
Br values were derived from uptake slope factors provided in USEPA 1992. Uptake slope is the ratio of contaminant
concentration in dry weight plant tissue to the mass of contaminant applied per hectare soil. Br aboveground values for mercuric
chloride and methyl mercury were calculated using methodology and data from Baes et al. (1984). Br forage values for mercuric
chloride and methyl mercury (on a dry weight basis) were obtained from USEPA 1997b. Hie EHRAP methodology assumes that
elemental mercury doesn't deposit onto soils. Therefore, it's assumed that there is no plant uptake through the soil.
b As discussed in EHRAP (USEPA 2005a), Appendix B, VG_motveg represents an empirical correction factor that reduces
produce concentration. Because of the protective outer skin, size, and shape of bulky produce, transfer of lipophilic chemicals
(i.e., log Kow greater than 4) to the center of the produce is not likely. In addition, typical preparation techniques, such as
washing, peeling, and cooking, further reduce the concentration of the chemical in the vegetable as consumed by removing the
high concentration of chemical on and in the outer skin, leaving the flesh with a lower concentration than would be the case if the
entire vegetable were pureed without washing. For belowground produce, EHRAP (USEPA 2005a) recommends using a
VG_rootveg value of 0.01 for PB-HAP with a log Kow greater than 4 and a value of 1.0 for PB-HAP with a log Kow less than 4
based on information provided in USEPA 1994b. In developing these values, USEPA (1994b) assumed that the density of the
skin and the whole vegetable are equal (potentially overestimating the concentration of PB-HAP in belowground produce due to
root uptake).
c As discussed in EHRAP (USEPA 2005a), Appendix B, VGag represents an empirical correction factor that reduces
aboveground produce concentration and was developed to estimate the transfer of PB-HAP into leafy vegetation versus bulkier
aboveground produce (e.g., apples). Because of the protective outer skin, size, and shape of bulky produce, transfer of lipophilic
PB-HAP (log Kow greater than 4) to the center of the produce is not likely. In addition, typical preparation techniques, such as
washing, peeling, and cooking, further reduces residues. For aboveground produce, EHRAP (USEPA 2005a) recommends using
a VG ag value of 0.01 for PB-HAP with a log Kow greater than 4 and a value of 1.0 for PB-HAP with a log Kow less than 4
based on information provided in USEPA 1994b. In developing these values, USEPA (1994b) assumed the following: (1)
translocation of compounds deposited on the surface of aboveground vegetation to inner parts of aboveground produce would be
insignificant (potentially underestimating the concentration of PB-HAP in aboveground produce due to air-to-plant transfer); (2)
the density of the skin and the whole vegetable are equal (potentially overestimating the concentration of PB-HAP in
aboveground produce due to air-to-plant transfer); and (3) the thickness of vegetable skin and broadleaf tree skin are equal
(effects on the concentration of PB-HAP in aboveground produce due to air-to plant transfer unknown).
For forage, EHRAP recommends a VG ag value of 1.0, also based on information provided in USEPA 1994b.
USEPA (1994b) does not provide a VG ag value for silage; the VG ag value for silage of 0.5 was obtained fromNC DEHNR
(1997); however, NC DEHNR does not present a specific rationale for this recommendation. Depending on the composition of
the site-specific silage, this value may under- or overestimate the actual value.
K-30
-------
Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Table K.7 lists additional non-chemical-specific input values for parameters used in the
algorithms that calculate chemical concentrations in produce. Unless otherwise noted, the default
parameter values were obtained from HHRAP. Refer to HHRAP (USEPA 2005a, Chapter 5 and
associated appendices) for detailed descriptions of these parameters and documentation of input
values.
K-31
-------
Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Table K.7. Non-Chemical-Specific Produce Inputs.
Plant Part
Interception
Fraction
(Rp)
(l/year)b
Length of
Plant
Exposure to
Deposition
(TP(i>)
(year)0
Yield or
Standing
Crop Biomass
(Ypw)
(kg/m2)d
Plant Tissue
Specific
Moisture
Adjustment
Factor (MAF(»)
(percent)6
Exposed Vegetable
0.982
18
0.16
5.66
92
Protected Fruit
na
na
na
na
90
Protected Vegetable
na
na
na
na
80
Forage (animal feed)
0.5
18
0.12
0.24
92
Exposed Fruit
0.053
18
0.16
0.25
85
Root Vegetables
na
na
na
na
87
Silage (animal feed)
0.46
18
0.16
0.8
92
Grain (animal feed)
na
na
na
na
90
Abbreviations: na = not applicable.
Source: USEPA 2005a.
a Baes et al. (1984) used an empirical relationship developed by Chamberlain (1970) to identify a correlation between initial Rp
values and pasture grass productivity (standing crop biomass [Yp\) to calculate Rp values for exposed vegetables, exposed fruits,
forage, and silage. Two key uncertainties are associated with using these values for Rp: (1) Chamberlain's (1970) empirical
relationship developed for pasture grass may not accurately represent aboveground produce. (2) Hie empirical constants
developed by Baes et al. (1984) for use in the empirical relationship developed by Chamberlain (1970) may not accurately
represent the site-specific mixes of aboveground produce consumed by humans or the site-specific mixes of forage or silage
consumed by livestock.
b The term kp is a measure of the amount of chemical that is lost to natural physical processes (e.g., wind, water) over time. The
HHRAP-recommended value of 18 yr"1 (also recommended by USEPA 1994a and 1998) represents the midpoint of a range of
values reported by Miller and Hoffman (1983). There are two key uncertainties associated with using these values for kp: (1) The
recommended equation for calculating kp includes a health protective bias in that it does not consider chemical degradation
processes. (2) Given the reported range of kp values from 7.44 to 90.36 yr"1, plant concentrations could range from about 1.8
times higher to about 5 times lower than the plant concentrations estimated in FFC media using the midpoint kp value of 18.
c HHRAP (USEPA 2005a) recommends using a Tp value of 0.16 years for aboveground produce and cattle silage. This is
consistent with earlier reports by USEPA (1994a, 1998) and NC DE1TNR (1997), which recommended treating Tp as a constant
based on the average period between successive hay harvests. Belcher and Travis (1989) estimated this period at 60 days. Tp is
calculated as 60 days 365 days/year = 0.16 years. For forage, the average of the average period between successive hay
harvests (60 days) and the average period between successive grazing (30 days) is used (that is, 45 days), and Tp is calculated as
(60 days + 30 days)/ 2 365 days/yr = 0.12 yr. Two key uncertainties are associated with use of these values for Tp: (1) The
average period between successive hay harvests (60 days) may not reflect the length of the growing season or the length between
successive harvests for site-specific aboveground produce crops. The concentration of chemical in aboveground produce due to
direct (wet and dry) deposition (Pd) will be underestimated if the site-specific value of Tp is less than 60 days, or overestimated if
the site-specific value of Tp is more than 60 days.
iYp values for aboveground produce and forage were calculated using an equation presented in Baes et al. (1984) and Shor et al.
(1982): Yp = Yhi/Ahi, where 17,, = Harvest yield of i'h crop (kg DW) and Am = Area planted to i'h crop (m2), and using values for 17,
and Ah fromUSDA (1994b and 1994c). A production-weighted U.S. average Yp of 0.8 kg dw/m2 for silage was obtained from
Shor et al. 1982.
eM4F represents the plant tissue-specific moisture adjustment factor to convert dry-weight concentrations into wet-weight
concentrations (which are lower owing to the dilution by water compared with dry-weight concentrations). Values obtained from
Chapter 10 of USEPA's 2003 SAB Review materials for 3MKA Modeling System, Volume II, "Farm Food Chain and Terrestrial
Food Web Data" (USEPA 2003a), which references USEPA 1997c. Note that the value for grain used as animal feed is based on
com and soybeans, not seed grains such as barley, oats, or wheat.
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Animal-Product Parameter Values
MIRC also requires chemical-specific inputs for many of the animal product algorithms. Table
K.8 lists the relevant values for the chemicals in MIRC considered in this assessment. The
HHRAP algorithms require additional inputs for the animal products calculations. These are not
specific to persistent and bioaccumulative hazardous air pollutants, but are specific to the animal
and animal product type. Table K.9 lists the soil and plant ingestion rates recommended in
HHRAP for beef cattle, dairy cattle, swine, and chicken.
Table K.8. Animal Product Chemical-specific Inputs for Chemicals Included in MIRC.
Soil Bio
Biotransfer Factors (Bam) (day/kg FW tissue)3
and Metabolism Factors (MF) (unitless)b
Compound Name
Availability
Factor (/is)
(unitless)
Mammal
Non mammal
Beef
(Bttbeef)
Dairy
(Bfldairy)
Pork
(15(1 pork )
MF
Eggs
(BUeggs)
Poultry
( Rllpoultrt)
MF
Inorganics
Cadmium compounds
1
1.2E-04
6.5E-06
1.9E-04
1
2.5E-03
1.1E-01
na
Mercury (elemental)
1
0
0
0
1
0
0
na
Mercuric chloride
1
1.1E-04
1.4E-06
3.4E-05
1
2.4E-02
2.4E-02
na
Methyl mercury
1
1.2E-03
1.7E-05
5.1E-06
1
3.6E-03
3.6E-03
na
PAHs
Acenaphthene
1
2.5E-02
5.2E-03
3.0E-02
0.01
1.0E-02
1.8E-02
na
Acenaphthylene
1
2.6E-02
5.5E-03
3.1E-02
0.01
1.1E-02
1.9E-02
na
Benz [a] anthracene
1
3.9E-02
8.3E-03
4.8E-02
0.01
1.7E-02
2.9E-02
na
Benzo[a]pyrene
1
3.8E-02
8.0E-03
4.6E-02
0.01
1.6E-02
2.8E-02
na
Benzo [b] fluoranthene
1
3.9E-02
8.3E-03
4.8E-02
0.01
1.7E-02
2.9E-02
na
Benzo(g,h,i)perylene
1
2.9E-02
6.1E-03
3.5E-02
0.01
1.2E-02
2.1E-02
na
Benzo |k| fluoranthene
1
3.8E-02
8.0E-03
4.6E-02
0.01
1.6E-02
2.8E-02
na
Chrysene
1
4.0E-02
8.4E-03
4.8E-02
0.01
1.7E-02
2.9E-02
na
Dibenz[a,h]anthracene
1
3.1E-02
6.5E-03
3.8E-02
0.01
1.3E-02
2.3E-02
na
Fluoranthene
1
4.0E-02
8.5E-03
4.9E-02
0.01
1.7E-02
3.0E-02
na
Fluorene
1
2.9E-02
6.1E-03
3.5E-02
0.01
1.2E-02
2.1E-02
na
Indeno [1,2,3 -c,d]pyrene
1
2.7E-02
5.8E-03
3.3E-02
0.01
1.2E-02
2.0E-02
na
Dioxins
OctaCDD, 1,2,3,4,6,7,8,9-
1
6.9E-03
1.4E-03
8.3E-03
1
2.9E-03
5.1E-03
na
OctaCDF, 1,2,3,4,6,7,8,9-
1
8.8E-03
1.8E-03
1.1E-02
1
3.7E-03
6.5E-03
na
HeptaCDD, 1,2,3,4,6,7,8-
1
8.8E-03
1.8E-03
1.1E-02
1
3.7E-03
6.5E-03
na
HeptaCDF, 1,2,3,4,6,7,8-
1
1.6E-02
3.5E-03
2.0E-02
1
6.9E-03
1.2E-02
na
HeptaCDF, 1,2,3,4,7,8,9-
1
2.4E-02
5.1E-03
3.0E-02
1
1.0E-02
1.8E-02
na
HexaCDD, 1,2,3,4,7,8-
1
1.1E-02
2.3E-03
1.3E-02
1
4.6E-03
8.1E-03
na
HexaCDF, 1,2,3,4,7,8-
1
2.3E-02
4.8E-03
2.8E-02
1
9.6E-03
1.7E-02
na
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Soil Bio
Biotransfer Factors (Bam) (day/kg FW tissue)3
and Metabolism Factors (MF) (unitless)b
Compound Name
Availability
Factor (/is)
(unitless)
Mammal
Non mammal
Beef
(Bttbeef)
Dairy
(Bddairy)
Pork
(15(1 pork )
MF
Eggs
(BUeggs)
Poultry
(Bitpoultry)
MF
HexaCDD, 1,2,3,6,7,8-
1
6.8E-03
1.4E-03
8.2E-03
1
2.9E-03
5.0E-03
na
HexaCDF, 1,2,3,6,7,8-
1
9.7E-03
2.0E-03
1.2E-02
1
4.1E-03
7.1E-03
na
HexaCDD, 1,2,3,7,8,9 -
1
6.8E-03
1.4E-03
8.2E-03
1
2.9E-03
5.0E-03
na
HexaCDF, 1,2,3,7,8,9-
1
1.4E-02
2.9E-03
1.7E-02
1
5.8E-03
1.0E-02
na
HexaCDF, 2,3,4,6,7,8-
1
9.6E-03
2.0E-03
1.2E-02
1
4.1E-03
7.1E-03
na
PentaCDD, 1,2,3,7,8-
1
1.8E-02
3.9E-03
2.2E-02
1
7.8E-03
1.4E-02
na
PentaCDF, 1,2,3,7,8-
1
2.6E-02
5.5E-03
3.2E-02
1
1.1E-02
1.9E-02
na
PentaCDF, 2,3,4,7,8-
1
3.1E-02
6.5E-03
3.8E-02
1
1.3E-02
2.3E-02
na
TetraCDD, 2,3,7,8-
1
2.6E-02
5.5E-03
3.2E-02
1
1.1E-02
1.9E-02
na
TetraCDF, 2,3,7,8-
1
3.6E-02
7.7E-03
4.4E-02
1
1.5E-02
2.7E-02
na
Abbreviations: MF = metabolism factors; na = not applicable.
Source: USEPA 2005a, unless otherwise indicated.
a As discussed in HHRAP (USEPA 2005a), Appendix A, biotransfer factors for mercury compounds were obtained from USEPA
1997b. Considering speciation, fate, and transport of mercury from emission sources, elemental mercury is assumed to be vapor-
phase and hence is assumed not to deposit to soil or transfer into aboveground plant parts. As a consequence, there is no transfer
of elemental mercury into animal tissues. Biotransfer factors for cadmium compounds were obtained from USEPA 1995b.
Biotransfer factors for dioxins and PAHs were calculated from chemical octanol-water partitioning coefficients (Kow values)
using the correlation equation from RTI (2005) and assuming the following fat contents: milk - 4%; beef - 19%; pork - 23%;
poultry -14%; and eggs - 8%.
b As discussed in HHRAP (USEPA 2005a), USEPA (1995c) recommends using a metabolism factor (AIF) to account for
metabolism of PAHs by mammals to offset the amount of bioaccumulation suggested by biotransfer factors. USEPA has
recommended an MF of 0.01 for bis(2-ethylhexyl)phthalate (BEHP) and 1.0 for all other chemicals (USEPA 1995d). For MIRC,
an MF of 0.01 is also used to calculate concentrations of PAHs in food products from mammalian species based on the work of
Hofelt et al. (2001). This factor takes into account the P450-mediated metabolism of PAHs in mammals; applying this factor in
the approach used in this analysis reduced the concentrations of chemicals in beef, pork, and dairy by two orders of magnitude.
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Table K.9. Soil and Plant Ingestion Rates for Animals.
Animal
Soil Ingestion Rate
Os(,„) (kg dw/day)a
Plant Part Consumed by
Animal
Plant Ingestion Rate
Qp(im) (kg dw/day)
Silage
2.5
Beef cattleb
0.5
Forage
8.8
Grain
0.47
Silage
4.1
Dairy cattle0
0.4
Forage
13.2
Grain
3.0
Swined
0.37
Silage
1.4
Grain
3.3
Chicken (eggs)6
0.022
Grain
0.2
Abbreviations: dw = dry weight;
Source: USEPA 2005a HHRAP (Chapter 5).
a Beef cattle: NC DEHNR (1997) and USEPA (1994b) recommended a soil ingestion rate for subsistence beef cattle of 0.5 kg/day
based on Fries (1994) andNRC (1987). As discussed in HHRAP, Fries (1994) reported soil ingestion to be 4% of the total dry
matter intake. NRC (1987) cited an average beef cattle weight of 590 kg, and a daily dry matter intake rate (non-lactating cows)
of 2% of body weight. This results in a daily dry matter intake rate of 11.8 kg dw/day and a daily soil ingestion rate of about 0.5
kg/day.
Dairy cattle: NC DEE1NR (1997) and USEPA (1994b) recommended a soil ingestion rate for dairy cattle of 0.4 kg/day based on
Fries (1994) andNRC (1987). As discussed inFlHRAP, Fries (1994) reported soil ingestion to be 2% of the total dry matter
intake. NRC (1987) cited an average beef cattle weight of 630 kg and a daily dry matter intake rate (non-lactating cows) of 3.2%
of body weight. This resulted in a daily dry matter intake rate of 20 kg/day dw, and a daily soil ingestion rate of approximately
0.4 kg/day Uncertainties associated with Qs include the lack of current empirical data to support soil ingestion rates for dairy
cattle and the assumption of uniform contamination of soil ingested by cattle.
Swine: NC DE1TNR (1997) recommended a soil ingestion rate for swine of 0.37, estimated by assuming a soil intake that is 8%
of the plant ingestion rate of 4.3 kg dw/day. Uncertainties include the lack of current empirical data to support soil ingestion rates
and the assumption of uniform contamination of the soil ingested by swine.
Chicken: F1HRAP (USEPA 2005a) assumes that chickens consume 10% of their total diet (which is approximately 0.2 kg/day
grain) as soil, a percentage that is consistent with the study from Stephens etal. (1995). Uncertainties include the lack of current
empirical data to support soil ingestion rates for chicken and the assumption of uniform contamination of soil ingested by
chicken.
b The beef cattle ingestion rates of forage, silage, and grain are based on the total daily intake rate of about 12 kg dw/day (based
on NRC [1987] reporting a daily dry matter intake that is 2% of an average beef cattle body weight of 590 kg) and are supported
by NC DE1TNR (1997), USEPA (1994b and 1990), and Boone etal. (1981). The principal uncertainty associated with these Op
values is the variability between forage, silage, and grain ingestion rates for cattle.
c The dairy cattle ingestion rates of forage, silage, and grain are based on the total daily intake rate of about 20 kg dw/day (NRC
1987; USEPA 1992) as recommended by NC DE1TNR (1997). Uncertainties include the proportion of each food type in the diet,
which varies with location. Assuming uniform contamination of plant materials consumed by cattle also introduces uncertainty.
dSwine are not grazing animals and are assumed not to eat forage (USEPA 1998). USEPA (1994b and 1998) andNC DE1TNR
(1997) recommended including only silage and grains in the diet of swine. USEPA (1995c) recommended an ingestion rate of 4.7
kg dw/day for a swine, referencing NRC (1987). Assuming a diet of 70% grain and 30% silage (USEPA 1990), F1HRAP
estimated ingestion rates of 3.3 kgfgrain dw]/day and 1.4 kg [silage dw]/day. Uncertainties associated with Op include variability
of the proportion of grain and silage in the diet, which varies from location to location.
e Chickens consume grain provided by the fanner. The daily quantity of grain feed consumed by chicken is assumed to be 0.2 kg
dw/day (Ensminger (1980), Fries (1982), andNRC (1987)). Uncertainties associated with this variable include the variability of
actual grain ingestion rates from site to site. In addition, assuming uniform contamination of plant materials consumed by chicken
introduces some uncertainty.
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
K.4.3. Adult and Non-Infant Exposure Parameter Values
This section summarizes the MIRC default exposure parameters and other value options for
adults and non-infants. The selected default values result in a highly health protective screening
scenario. This assessment uses parameter value options from EPA's Exposure Factors Handbook
(EFH; USEPA 2011) and Child-Specific Exposure Factors Handbook (CSEFH; USEPA 2008a).
We use time-weighted average values for age groupings other than those used in MIRC (see
Section K.2.2 above for MIRC age groups).
To evaluate ingestion rates for home-produced farm food items, MIRC categorizes food as:
exposed and protected fruit, exposed and protected vegetables, root vegetables, beef, total dairy
products, pork, poultry, and eggs. Within MIRC, those ingestion rates are already normalized to
body weight (i.e., g wet weight/kg-day) (USEPA 2011). The body weight parameter values
presented in Table K.10, therefore, are not applied in the chemical intake (ADD) equations for
these food types.
MIRC also includes ingestion rates for drinking water (mL/day), soil (mg/day), and fish (g/day).
These ingestion rates, however, are calculated on a per person basis, that is, they are not
normalized for body weight. The body weight parameter values presented in Table K. 10,
therefore, are applied in the chemical intake (ADD) equations for these media.
Body Weights
Body weight (BW) options included in MIRC include mean, 5th, 10th, 50th, 90th, and 95th
percentile values for adults and the five children's age groups: <1 year; 1-2 years; 3-5 years; 6-
11 years; and 12-19 years. For its default screening assessment and this assessment of livestock
carcass management options from deaths during a natural disaster, USEPA uses the mean BW
for each age group. Table K. 10 lists the BWs currently in the MIRC database.
In general, BW values for the five children's age groups are calculated from the summary data
provided in Table 8-3 of USEPA's 2008 CSEFH. For comparison, we estimated alternative BW
values for children ages 12 through 19 years using data from Portier et al. (2007). Those values
(see last row of Table K. 10), are not included in MIRC. However, the 64 kg calculated mean is
the same from either of the two methods for children ages 12 through 19 years. The other
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
percentile values for this age group differed by approximately 10% or less using the two
methods.
Table K.10. Mean and Percentile Body Weight Estimates for Adults and Children.
Lifestage
Duration
Body Weight (kg)
(years)
(years)
Mean
5th
10th
50th
90th
95th
Adult3 (20-70)
50
80.0a
52.9
56
69.3
89.7
97.6
Child < lb
1
7.83
6.03
6.38
7.76
9.24
9.66
Child 1-2°
2
12.6
9.9
10.4
12.5
14.9
15.6
Child 3-5d
3
18.6
13.5
14.4
17.8
23.6
26.2
Child 6-1 le
6
36.0
22.1
24.0
33.5
51.2
58.6
Child 12-19f
8
64.2
39.5
45
64.2
83.5
89
[Child 12-19]*
8
64.3
41.1
44.6
60.9
88.5
98.4
Abbreviations: BW = body weight.
a BW represents the recommended body weight from USEPA's (2011) EFH. Although the 18 to 74 year age category in
USEPA's EFH does not match exactly the age 20 to 70 year categorization of adults in MIRC, the magnitude of error in the mean
and percentile body weights is likely to be very small (i.e., less than 1%).
bEach BW represents a time-weighted average of body weights for age groups birth to <1 month, 1 to <3 months, 3 to <6
months, and 6 to <12 months from Table 8-3 of USEPA's (2008a) CSEFH. Original sample sizes for each of these age groups
can also be found in Table 8-3.
c Each BW represents a time-weighted average of body weights for age groups 1 to <2 years and 2 to <3 years from Table 8-3 of
the 2008 CSEFH. Original sample sizes for each of these age groups can also be found in Table 8-3.
dBWs obtained directly from Table 8-3 of the 2008 CSEFH (age group 3 to <6 years).
e Each BW represents a time-weighted average of body weights for age groups 6 to <11 years and 11 to <16 years from Table 8-3
of the 2008 CSEFH. Original sample sizes for each of these age groups can also be found in Table 8-3.
fMean BW estimated using Table 8-22 of the 2008 CSEFH, which is based on NHANES IV data as presented in Portier et al.
(2007). This estimate was calculated as the average of the 8 single-year age groups from 12 to 13 years through 19 to 20 years.
Values for the other percentiles were estimated using Portier et al. (2007).
gEach BW represents a time-weighted average of body weights for age groups 11 to <16 years and 16 to <21 years from Table 8-
3 of the 2008 CSEFH. Estimated values include 11-year-olds and individuals through age 20, which contributes to uncertainty in
the estimates for 12 to 19 years. Those values are provided for comparison purposes only and are not included in MIRC.
Water Ingestion Rates
MIRC options allow calculation of chemical ingestion via drinking water obtained from surface-
water sources or from groundwater wells in the contaminated area. Users can set drinking water
ingestion rates to zero or revise the drinking water ingestion rates to better reflect site-specific
water uses. USEPA's (2008a) CSEFH recommends values for drinking water ingestion rates for
children based on a study reported by Kahn and Stralka (2008). Table 3-4 of the 2008 CSEFH
provides per capita estimates of community water ingestion rates by age categories. Community
water ingestion includes both direct and indirect ingestion of water from the tap. Direct ingestion
is defined as the direct consumption of water as a beverage, while indirect ingestion includes
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
water added during food or beverage preparation. The source of these data is the 1994-1996 and
1998 USDA's Continuing Survey of Food Intakes by Individuals (CSFII) (USDA 2000). Table
K. 11 includes the drinking water ingestion rates for children that are included in MIRC.
This assessment obtained mean and percentile adult drinking water ingestion rates from USEPA
(2004), which presents estimated per capita water ingestion rates for various age categories based
on data collected by the USDA's 1994-1996 and 1998 CSFII (USDA 2000). Adult ingestion
rates, presented in Table K. 11, represent community water ingestion, both direct and indirect as
defined above, for males and females combined, ages 20 years and older.
Table K.11. Estimated Daily Per Capita Mean and Percentile Water Ingestion Rates.3
Lifestage (years)
Ingestion Rates, Community Water (mL/day)
Mean
50th
90th
95th
99th
Child
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
local Food Ingestion Rates
MIRC includes mean, median, 90th, 95th, and 99th percentile food-specific ingestion rates (IRs)
for adult and child consumers of the ten categories of farm-raised produce and animal products.
This assessment uses mean values from USEPA's analysis of data from the USDA's 1987 to
1988 Nationwide Food Consumption Survey (NFCS) (USDA 1993), as presented in Chapter 13
of the Agency's Exposure Factors Handbook (i.e., Intake Rates for Various Home Produced
Food Items) (USEPA 2011). "Consumers only" include only individuals who reported eating a
specified type of food during the three-day period covered by the survey. "Per capita" IRs
include all persons surveyed whether they consumed the food type or not; those data are not
included in MIRC. The NFCS questionnaire included five options for a household to self-
identify: gardens, raises animals, hunts, fishes, or farms. As of September 2008, that survey
provided the most recent NFCS data available (USEPA 2008a, CSEFH).26 As of April 2016,
online Google searches did not identify more recent USDA NFCS surveys.
Following USEPA's analysis, we compiled data for two types of households to consider adult
IRs: (1) households that farm (F), and (2) households that garden or raise animals (HG for
homegrown). This division reflects the Survey's "Response to Questionnaire" (USEPA 2011,
Chapter 13) and how USEPA tabulated the results. The first type of household, F, represents
farmers who might both grow crops and raise animals and who are likely to consume more
homegrown/raised foods than the second type of household. The second type of household, HG,
represents the non-farming households that may consume lower amounts of homegrown or
raised foods (i.e., HG encompasses both households that garden and households that raise
animals).
The food-specific ingestion rates reflect the amount of each food type that F and HG households
produce and bring into their homes for consumption. USEPA averaged the reported consumption
rate for homegrown foods over the 1-week survey period.
Table K. 12 lists the mean food-specific ingestion rates for adults in F households. In MIRC,
users can specify the use of HG ingestion rates if they are more appropriate for the user's
26 Note that EPA's 2008 CSEFH does not distinguish between exposed and protected fruits and vegetables when
recommending food ingestion rates based on the same data set for the same age categories. USEPA's 1997 analysis
for its EFH therefore remains the most appropriate data source for use in MIRC.
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
exposure scenario. Table K.12 reflects consumers only. Those who did not report consumption
of a given food type during the survey are not included (USEPA 2011, Chapter 13).
For children, USEPA estimated food-specific IRs for four age categories (USEPA 2011): 1-2
years, 3-5 years, 6-11 years, and 12-19 years. Sample sizes are insufficient to distinguish IRs
for children in different types of households. Consequently, MIRC uses a single IR value in both
F and HG households for a given food type and age category (Table K. 12). When there were
fewer than 20 observations representing a subpopulation for a food type and age category,
USEPA had insufficient data to develop consumer-only intake rates.
Table K.12. Summary of Consumer-only, Age-Group-Specific Mean Food Ingestion Rates
for Farm-Grown Foods
Product
Child (age in yr)
Adult
<1
1 2
3 5
6 11
12 19
(20 70 yr)
Mean ingestion rates (g/kg-day)
Beef
na
4.14
4.00
3.77
1.72
1.93
Dairyb
na
91.6
50.9
27.4
13.6
2.96
Eggs3
na
2.46
1.42
0.86
0.588
0.606
Exposed Fruit3
na
6.14
2.60
2.52
1.33
1.19
Exposed Vegetable3
na
3.48
1.74
1.39
1.07
1.38
Pork3
na
2.23
2.15
1.50
1.28
1.10
Poultry3
na
3.57
3.35
2.14
1.50
1.37
Protected Fruit3
na
16.6
12.4
8.50
2.96
5.19
Protected Vegetable3
na
2.46
1.30
1.10
0.78
0.862
Root Vegetable3
na
2.52
1.28
1.32
0.94
1.03
Water (mL/day)c
na
332
382
532
698
1218
Median ingestion rates (g/kg-day)
Beef
na
2.51
2.49
2.11
1.51
1.55
Dairyb
na
125
66.0
34.4
15.5
2.58
Eggs3
na
1.51
0.83
0.561
0.435
0.474
Exposed Fruit3
na
1.82
1.11
0.61
0.62
0.593
Exposed Vegetable3
na
1.89
1.16
0.64
0.66
0.812
Pork3
na
1.80
1.49
1.04
0.89
0.802
Poultry3
na
3.01
2.90
1.48
1.30
0.922
Protected Fruit3
na
7.59
5.94
3.63
1.23
2.08
Protected Vegetable3
na
1.94
1.04
0.79
0.58
0.564
Root Vegetable3
na
0.46
0.52
0.57
0.56
0.59
Water (mL/day)c
na
255
316
417
473
981
90th percentile ingestion rates (g/kg-day)
Beef
na
9.49
8.83
11.4
3.53
4.41
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Product
Child (age in yr)
Adult
<1
1 2
3 5
6 11
12 19
(20 70 yr)
Dairyb
na
185
92.5
57.4
30.9
6.16
Eggs3
na
4.90
3.06
1.90
1.30
1.31
Exposed Fruit3
na
12.7
5.41
6.98
3.41
2.37
Exposed Vegetable3
na
10.7
3.47
3.22
2.35
3.09
Pork3
na
4.90
4.83
3.72
3.69
2.23
Poultry3
na
7.17
6.52
4.51
3.13
2.69
Protected Fruit3
na
44.8
32.0
23.3
7.44
15.1
Protected Vegetable3
na
3.88
2.51
2.14
1.85
1.81
Root Vegetable3
na
7.25
4.26
3.83
2.26
2.49
Water (mL/day)c
na
687
778
1149
1640
2534
95th percentile ingestion rates (g/kg-day)
Beef
na
12.9
12.5
12.5
3.57
5.83
Dairyb
na
167
89.9
56.0
32.3
7.80
Eggs3
na
5.38
3.62
2.37
1.43
1.59
Exposed Fruit3
na
14.6
6.07
11.7
4.78
3.38
Exposed Vegetable3
na
11.9
6.29
5.47
3.78
4.46
Pork3
na
6.52
6.12
4.73
6.39
2.60
Poultry3
na
8.10
7.06
5.07
3.51
3.93
Protected Fruit3
na
48.3
35.1
26.9
11.4
19.2
Protected Vegetable3
na
9.42
5.10
3.12
2.20
2.83
Root Vegetable3
na
10.4
4.73
5.59
3.32
3.37
Water (mL/day)c
na
903
999
1499
2163
3087
99th percentile ingestion rates (g/kg-day)
Beef
na
20.9
19.8
13.3
4.28
6.84
Dairyb
na
180
87.2
54.8
34.7
9.20
Eggs3
na
16.2
11.2
8.19
4.77
1.83
Exposed Fruit3
na
25.2
32.5
15.7
5.9
13.0
Exposed Vegetable3
na
12.1
7.36
13.3
5.67
8.42
Pork3
na
8.71
9.74
6.61
4.29
3.87
Poultry3
na
9.63
10.24
6.12
4.60
4.93
Protected Fruit3
na
109
71.2
58.2
19.1
34.4
Protected Vegetable3
na
9.42
5.31
5.40
2.69
5.56
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Product
Child (age in yr)
Adult
<1
1 2
3 5
6 11
12 19
(20 70 yr) |
Root Vegetable3
na
10.4
4.73
7.47
5.13
7.57
Water (mL/day)c
na
1318
1592
2274
3467
4567
Abbreviations: na = not applicable; yr = year(s).
a Primary source for values was the 1987-1988 NFCS survey; compiled results are presented in Chapter 13 of USEPA's (2011)
Exposure Factors Handbook. When data were unavailable for a particular age group, intake rate for all age groups was used
multiplied by the age-specific ratio of intake based on national population intake rates from CSFII.
b Primary source for values was 1987-1988 NFCS survey, compiled results presented in Chapter 13 of 2011 Exposure Factors
Handbook (USEPA 2011). When data were unavailable for a particular age group, intake rate for all age groups was used
multiplied by the age-specific ratio of intake based on national population intake rates from an NHANES 2003-2006 analysis in
Chapter 11 of the 2011 Exposure Factors Handbook.
c Primary source for children less than 3 years of age was a Kahn and Stralka (2008) analysis of CSFII data, and from EPA's
analysis of NHANES 2003-2006 data for children and adults greater than three. All data tables that were used and justifications
for data sources are presented in Chapter 3 of the 2011 Exposure Factors Handbook.
As referenced in Section 6.2.2.2, HHRAP recommends a method for calculating age-specific
consumer ingestion rates. In general, refer to the HHRAP documentation for calculations used in
the case of "missing" age-specific consumer-only IRs. In this assessment, food-specific intake
rates for those child age groups and food items not included in Chapter 13 of the 2011 EFH
((IRage group x) are derived using the following information:
¦ Mean consumer-only intake of the farm food item, as brought into the home, for the total NFCS survey
population (from EFH Chapter 13)—IRCO_total
1 Mean per capita intake of the food type from all sources, as consumed, for the specific child age group, from
Chapter 3 of the CSFII Analysis of Food Intake Distributions (USEPA 2003b)—IRPC, age_group_x
1 Mean per capita intake of the farm food item for the total CSFII survey population (from Chapter 3 of USEPA
2003b )—IRPC_total
The ratio of IRPC, agegroupx to IRPC total from the CSFII data shows the consumption rate
of a particular food type by a specific age group, relative to the consumption rate for that food
type for the population as a whole. The ratio of IRCO, age group x to IRCO total, that is the
consumption rate of a particular food type by a specific age group (consumers only) relative to
the consumption rate for that food type for the NFCS survey population as a whole (consumers
only), should be approximately the same.
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
local Fish Ingestion Rates
MIRC uses the USEPA's (2002) analysis of freshwater and estuarine fish consumption from the
USDA's Continuing Survey of Food Intake by Individuals (CSFII) for 1994-96 and 1998 to
provide fish ingestion rate options by age category. Although the fish consumption rates reported
in the CSFII include all sources, commercial and self-caught, for purposes of screening level risk
assessments, this assessment assumes that all freshwater and estuarine fish consumed are self-
caught. The inclusion of commercially obtained and estuarine fish will overestimate locally
caught freshwater fish ingestion rates for most populations in the United States; however, it also
might underestimate locally caught fish ingestion rates for some populations (e.g., Native
Americans, Asian and Pacific Island communities, rural African American communities).
Because consumption of locally caught fish varies substantially from region to region in the
United States and from one population or ethnic group to the next, users of MIRC are
encouraged to use more locally relevant data whenever available. This assessment did not use
fish ingestion data representative of an Iowa farm to avoid limiting the applicability of the
assessment's results to that specific part of the country.
MIRC also includes values for the mean and the 90th, 95th, and 99th percentile fish per capita
ingestion rates (freshwater and estuarine fish only) for children based on the USEPA's analysis
of 1994-96 and 1998 CSFII data (USEPA 2002, 2008a). Those rates include both children who
eat fish and those who do not. As shown in USEPA's 2008 CSEFH, Table 10-7, the per capita
ingestion rates for some child-age groups often are zero. While this may reflect the relatively
short-term of the survey, it also can represent relatively infrequent consumption of fish. In
general, children appear to eat fish on the order of once a week to once a month or less compared
with the near daily ingestion of other types of food products (e.g., dairy, produce, meat). In a
quantitative model such as MIRC, zero fish ingestion rates are not useful so this assessment
developed an alternative method to estimate fish ingestion rates for children and adults that could
provide reasonable, non-zero values likely to approximate a mean value for all age groups.
In the alternative method, the assessment derives age-group-specific fish ingestion rates by using
values for each age group, y that meet two criteria:
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
¦ Mean consumer-only fish ingestion rates for age group y, IRCO,y, from EPA's Estimated Per Capita Fish
Consumption in the United States (USEPA 2002, Section 5.2.1.1, Table 5, for freshwater/estuarine habitat)27
¦ Fraction of the population consuming freshwater/estuarine fish, FPC,y, calculated as consumer-only sample
size / U.S. population sample for age group y. The data to calculate those fractions are available in the 2008
CSEFH and USEPA 2002
Calculation of Alternative Age-Group-Specific Fish Ingestion Rates. Equation K.3 calculates
the alternative, per capita fish ingestion rates by age group (IRPC,y):
IRpCy = IRcOy * FpCy (Eqn. K.3)
where:
IRpc.y = Per capita fish ingestion rate for age groups (g/day)
tn - Consumer-only fish ingestion rates for age group y (g/day) (USEPA
co,y 2002, Section 5.2.1.1, Table 5, for freshwater/estuarine habitat)
Fraction of the population consuming freshwater/estuarine fish,
Fpc.y = calculated as consumer-only sample size / total U.S. population sample
size for age group y (unitless) (2008 CSEFH, USEPA 2002)
In the above, per capita (as opposed to consumer-only) indicates intake rates for the entire
population rather than the subset of the population that ingests the particular food category. Here,
the HHRAP methodology recommends using per capita ingestions, because there are no
consumer percentile specific intakes provided for the different age groups.
27 Table 10-9 of the CSEFH provides mean and upper percentile values, but does not include median values, because
USEPA prefers use of mean to median values for exposure assessment (USEPA 2008).
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Table K. 13 shows the mean and percentile consumer fish ingestion rates for children and adults
and the fraction of the population consuming freshwater/estuarine fish used to calculate long-
term per capita fish ingestion rates by age group. Table K. 15 summarizes the mean and
percentile per capita fish ingestion rates estimated using the above approach. The fish ingestion
rates provided in Table K. 15 and included in MIRC are intended to represent the harvest and
consumption of fish in surface waters in a hypothetical depositional area. Among the ingestion
rates presented in Table K.16, the mean values for adults and children aged 1-2 are used for the
exposure assessment of livestock carcass management options.
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Table K.13. Daily Mean and Percentile Consumer-Only Fish Ingestion Rates for Children
and Adults (IRCO,y).a
Ingestion Rates, All Fish (g/day)
Lifestage (years)
Mean
50th
90th
95th
99th
Child <1
na
na
na
na
na
Child l-2b
27.31
15.61
64.46
87.60
138.76*
Child 3-5c
40.31
23.04
95.16
129.31
204.84*
Child 6-1 ld
61.49
28.46
156.86*
247.69*
385.64*
Child 12-19e
79.07
43.18
181.40*
211.15*
423.38*
Adult1
81.08
47.39
199.62*
278.91
505.65*
Abbreviations: na = not applicable, we assume that children < 1 year of age do not consume fish.
Sources: USEPA 2002, 2008a
*Indicates that the sample size does not meet minimum reporting requirements as described in USEPA 2002. Owing to the small
sample sizes, these upper percentiles values are highly uncertain.
a Per capita fish ingestion rates (IR) for children by age group are available from Chapter 10 of the CSEFH (USEPA 2008a);
however, all 50th and some 90th percentile ingestion rates are zero. Per capita fish IRs were therefore estimated as described in
Equation J. 1 to provide reasonable, non-zero values for all age groups and percentiles.
b A fish IR for ages 1-2 years was not available. Hie value represents the consumer-only fish IR for ages 3 to 5 from USEPA
(2002) (Section 5.2.1.1 Table 5 [freshwater/estuarine habitat]), scaled down by the ratio of the mean Child 1-2 body weight to the
mean Child 3-5 body weight.
c These values represent the consumer-only fish IR for ages 3 to 5 from USEPA (2002), Section 5.2.1.1 Table 5 (freshwater/
estuarine habitat). Sample size = 442.
d These values represent the consumer-only fish IR for ages 6 to 10 from USEPA (2002), Section 5.2.1.1 Table 5 (freshwater/
estuarine habitat). Sample size = 147.
e These values represent the time-weighted average per capita fish IR for ages 11 to 15 and 16 to 17 years from USEPA (2002),
Section 5.1.1.1 Table 5 (freshwater/estuarine habitat); the value may underestimate ingestion rate for ages 12 to 19 years. Sample
size = 135.
1 These values represent the consumer-only fishIR for individuals 18 years and older from USEPA (2002), Section 5.2.1.1 Table
4 (freshwater/estuarine habitat). Sample size = 1,633.
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Table K.14. Fraction of Population Consuming Freshwater/Estuarine Fish on a Single Day
(¦FPC,y).
Lifestage (years)
Fraction Consuming Fish
Child 3-5
0.05033
Child 6-11
0.0440b
Child 12-19
0.0493°
Adult
0.08509d
Sources: USEPA 2002, 2008a
a This value was calculated using the ages 3 to 5 sample size for consumers only divided by the sample size for the U.S.
population divided by 2 to represent the proportion consuming fish on a single day (the consumers-only group includes
individuals who consumed fish on at least one of two survey days) to match the one-day ingestion rate.
b As in endnote "a," the value was calculated using the ages 6-10 sample size for consumers only divided by the sample size for
U.S. population divided by 2.
c Hie value was calculated by summing the ages 11-15 and 16-17 sample sizes for consumers only and dividing by both by the
sum of the sample sizes for U.S. population and by a factor of 2.
d The value was calculated using the ages 18 and older sample size for consumers only divided by the sample size for U.S.
population. The result was divided by 2 to represent a one-day sampling period in order to match the one-day ingestion rate.
Table K.15. Calculated Long-term Mean and Percentile per capita Fish Ingestion Rates for
Children and Adults (IRPQy).
Lifestage (years)
Ingestion Rates (IR), All Fish (g/day)
Mean
50th
90th
95th
99th
Child <1
na
na
na
na
na
Child l-2a
1.37
0.79
3.24
4.41
6.98
Child 3-5b
2.03
1.16
4.79
6.51
10.3
Child 6-1 lc
2.71
1.25
6.90
10.9
17.0
Child 12-19d
3.90
2.13
8.95
10.4
20.9
Adult6
6.90
4.03
16.99
23.73
43.02
Abbreviations: na = not applicable assuming that children < 1 year of age do not consume fish; IR = ingestion rates.
Sources: USEPA 2002, 2008a
a Values were calculated as (consumer-only IR for Child 1-2) x (fraction of population consuming fish for Child 1-2).
b Values were calculated as (consumer-only IR for Child 3-5) x (fraction of population consuming fish for Child 3-5).
c Values were calculated as (consumer-only IR for Child 6-11) x (fraction of population consuming fish for Child 6-11).
d Values were calculated as (consumer-only IR estimated for Child 12-19) x (fraction of population estimated to consume fish for
Child 12-19).
e Values were calculated as (consumer-only IR for Adults) x (fraction of population consuming fish for Adults).
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Soil Ingestion Rates
Adults might accidentally ingest soil during gardening activities, and individuals might ingest
soil particles that adhere to exposed fruit, as well as exposed and belowground vegetables. Soil
that is re-suspended in the air by wind can resettle on exposed fruits and vegetables. Children can
ingest soils in those ways, but children playing outdoors also ingest soils directly or by hand-to-
mouth activities during play. MIRC includes soil ingestion rate options by age group for these
types of exposures. MIRC does not include geophagy options for children who may exhibit pica,
or the recurrent ingestion of unusually high amounts of soil (i.e., on the order of 1,000-5,000
mg/day or more) (USEPA 2008a).
Data on soil ingestion rates are sparse; the MIRC soil ingestion rates listed in Table K.16 are
based on very limited data. The studies evaluated by USEPA for children generally focused on
children aged 1-2 and 3-5 years old and are not specific to families that garden or farm. The
default ingestion rates in MIRC are the 90th percentile values, as for other ingestion rate
parameters. For the exposure assessment for cattle management options, MIRC values are set
instead to mean values.
Table K.16. Daily Mean and Percentile Soil Ingestion Rates for Children and Adults.
Age Group
Soil Ingestion Rate (mg/day)
(years)
Mean3
50th a
90th
95th
99th
Child 1-2
50
50
200b
200b
200b
Child 3-5
50
50
200b
200b
200b
Child 6-11
50
50
201°
33 ld
33 ld
Child 12-19
50
50
201°
33 ld
33 ld
Adult 20-70
20
20
201°
33 ld
33 ld
Sources: USEPA 2008a, USEPA 2011
a For mean and 50th percentile soil ingestion rates for children, value represents a "central tendency" estimate from USEPA's
(2008a) CSEFH, Table 5-1. For adults, value is the recommended mean value for adults from USEPA's (2011) EFH, Chapter 5,
Table 5-1.
b Values are the recommended "upper percentile" value for children from USEPA's 2011 EFH, Chapter 4, Table 4-23. The 2008
CSEFH and 2011 EFH included a high-end value associated with pica only, but this value has not been used.
c Values are 90th percentile adult ingestion rates calculated in Stanek et al. (1997); used to represent older children and adults.
d Values are 95th percentile adult ingestion rates calculated in Stanek et al. (1997); used to represent older children and adults.
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Total Food Ingestion Rates
This assessment uses the mean total food ingestion rates presented in Table K. 17 to normalize or
truncate the sum of food-specific ingestion rates to reasonable values.
Table K.17. Daily Mean and Percentile Per Capita Total Food Intake for Children and
Adults.
Lifestage (years)
Percent of Group
Consuming Food
Mean
50th
90th
95th
99th
Total Food Intake (g/day, as consumed)
Child < la
67.0%- 99.7% h
322
270
599
779
1152
Child l-2b
100%
1,032
996
1537
1703
2143
Child 3-5°
100%
1,066
1,020
1,548
1,746
2,168
Child 6-1 ld
100%
1,118
1,052
1,642
1,825
2,218
Child 12-19®
100%
1,197
1,093
1,872
2,231
2,975
Adultf
100%
1,100
1,034
1,738
2,002
2,736
Total Food Intake (g/kg-day, as consumed)
Child < la
67.0%- 99.7% h
39
34
72
95
147
Child l-2b
100%
82
79
125
144
177
Child 3-5°
100%
61
57
91
102
132
Child 6-1 ld
100%
40
38
61
70
88
Child 12-19®
100%
21
19
34
40
51
Adult8
100%
14.8
13.9
23.7
27.6
35.5
Abbreviations: in endnotes, N = sample size.
Sources: USEPA (2005e) analysis of CSFII data and USEPA (2008a) CSEFH.
a These values represent a time-weighted average for age groups birth to <1 month (N=88), 1 to <3 months (N=245), 3 to <6
months (N=411), and 6 to <12 months (N=678) from Table 14-3 of the 2008 CSEFH.
These values represent a time-weighted average for age groups 1 to <2 years (N= 1,002) and 2 to <3 years (N=994) from Table
14-3 of the 2008 CSEFH.
c These values were obtained from Table 14-3 of the 2008 CSEFH (age group 3 to <6 years, N=4,l 12).
d These values were obtained from Table 14-3 of the 2008 CSEFH (age group 6 to <11 years, N=l,553). These values represents
a health protective (i.e., slightly low) estimate for ages 6 through 11 years since 11-year olds are not included in this CSEFH age
group.
e These values represent a time-weighted average for age groups 11 to <16 years (N=975) and 16 to <21 (N=743) years from
Table 14-3 of the 2008 CSEFH. Note that estimated values include 11-year-olds and individuals through age 20, which
contributes to uncertainty in the estimates.
fThese values represent a time-weighted average for age groups 20 to 39 years (N=2,950) and 40 to 69 years (N=4,818) from
Table 5B of the 2005 USEPA analysis of CSFII.
g These values represent a time-weighted average for age groups 20 to 39 years (N=2,950) and 40 to 69 years (N=4,818) from
Table 5A of the 2005 USEPA analysis of CSFII.
hPercents consuming foods from Table 14-3 of the 2008 CSEFH include: 67.0% (birth to <1 month); 74.7% (1 to <3 months);
93.7% (3 to <6 months); and 99.7% (6 to <12 months). Infants under the age of 1 that consume breast milk are classified as "non-
consumers" of food.
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
This procedure would be particularly important if one estimated chemical intake from multiple
upper-percentile food ingestion rates for different types of food were added together. Percentiles
(including medians) are not additive, and adding multiple upper percentiles can yield
unrealistically high values that exceed the maximum observed (or likely possible) long-term
ingestion rate (see Section 5.2.3 of main report). Individuals representing the upper percentile
ingestion rate for one food category might not be the same individuals who reported high
percentile ingestion rates for one or any of the other food categories.
K.4.4. Other Exposure Factor Values
The other exposure parameters included in the MIRC algorithms are exposure frequency, the
fraction of the food type obtained from the contaminated area, and the reduction in the weight of
the food types during preparation and cooking. The following subsections briefly discuss each of
these topics.
Exposure Frequency
The exposure frequency (EF) represents the number of days per year that an individual consumes
home-produced food items contaminated with the chemical being evaluated. In MIRC, the
default value for EF is 365 days/year for all exposure sources and all potential receptors. This
assumption is consistent with the food ingestion rates used in MIRC (i.e., average daily intake
rates equivalent to annual totals divided by 365 days), but does not imply that residents
necessarily consume home-produced food products every day of the year. MIRC users can
specify lower EF values for various food types when residents obtain some of their diet from
commercial sources or when consumption of homegrown produce is seasonal. To evaluate daily
intake rates based on shorter averaging times, MIRC users can overwrite both the food-specific
ingestion rates and the EF for each homegrown food product.
Fraction Contaminated
The fraction contaminated (FC) represents the portion of each food product consumed that
contains the chemical at a level consistent with environmental concentrations in the area of
concern (e.g., area with maximum deposition rates). MIRC includes the default FC of 1.0, i.e.,
assumes 100% of the food consumed is produced by households that farm, garden, or raise
animals. Obviously, this is the most health protective assumption because it maximizes the
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
impact of consuming food from the location represented by the chemical concentrations input
into the model. While MIRC users can vary this default FC value for individual food products to
tailor the assessment to a particular exposure scenario, this assessment retained the default value.
Preparation and Cooking Losses
The actual food ingested generally is less than the amount brought into a home. Food preparation
and cooking losses are included in the FFC exposure calculations to account for amounts of food
products that are not ingested due to loss during preparation, cooking, or post-cooking. The ADD
equations account for these losses, because the food ingestion rates calculated from the USD A
1987 to 1988 NFCS are based on the weight of products as brought into the house prior to any
type of preparation. Not all of the produce or products are eventually ingested. In general, some
parts of the produce and products are discarded during preparation while other parts might not be
consumed even after cooking (e.g., bones).
MIRC includes three distinct types of preparation and cooking losses in the ingestion exposure
algorithms: (1) loss of part of the food (i.e., removal of the skin from vegetables and fruit by
paring, removing pits, coring, deboning), (2) loss of weight during cooking (e.g., evaporation of
water, fats remaining in a cooking vessel), and (3) post-cooking loss (e.g., non-consumption of
bones or draining cooking liquid). MIRC includes mean values for these three types of
preparation and cooking losses for all of the categories of food. Nevertheless, because different
types of losses apply to different types of foods, MIRC uses two parameters (LI and L2), to vary
the loss according to the food type (see footnotes to Table K. 18).
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Table K.18. Fraction Weight Losses from Preparation of Various Foods.
Product
Mean Cooking, Paring, or
Preparation Loss
(Cooking Loss Type 1 [LI])
(unit less)11
Mean Net Post Cooking
(Cooking Loss Type 2 [L2\)
(unitless)b
Exposed Fruit0
0.244
0.305
Exposed Vegetable
0.162d
na
Protected Fruit
0.29e
na
Protected Vegetable
0.088f
na
Root Vegetable8
0.075
0.22
Beef
0.27
0.24
Pork
0.28
0.36
Poultry
0.32
0.295h
Fish1
0.0
0.0
Abbreviations: na = not available.
Source: USEPA 1997a and 2011, Chapter 13 (specific tables identified below).
a Forfniits, includes losses from draining cooked forms. For vegetables, includes losses due to paring, trimming, flowering the
stalk, thawing, draining, scraping, shelling, slicing, husking, chopping, and dicing and gains from the addition of water, fat, or
other ingredients. For meats, includes dripping and volatile losses during cooking.
bFor fniits, includes losses from removal of skin or peel, core or pit, stems or caps, seeds and defects; may also include losses
from removal of drained liquids from canned or frozen forms. For vegetables, includes losses from draining or removal of skin.
For meats, includes losses from cutting, shrinkage, excess fat, bones, scraps, and juices.
c These values represent averages of means for all fruits with available data (except oranges) (Table 13-6).
dThis value represents an average of means for all exposed vegetables with available data (Table 13-7). Exposed vegetables
include asparagus, broccoli, cabbage, cucumber, lettuce, okra, peppers, snap beans, and tomatoes.
e This value was set equal to the value for oranges (Table 13-6).
fThis value represents an average of means for all protected vegetables with available data (Table 13-7). Protected vegetables
include pumpkin, com, peas, and lima beans.
g These values represent averages of means for all root vegetables with available data (Table 13-7). Root vegetables include beets,
carrots, onions, and potatoes.
hThis value represents an average of means for chicken and turkey (Table 13-5).
1 If the user changes fish ingestion rates to match a survey of the whole weight of fish brought into the home from the field
(divided by the consumers of the fish), an appropriate value for LI would be 0.31 and an appropriate L2 would be 0.11 (USEPA
2011).
All preparation and cooking loss parameter values are estimated as specified in Table K.18's
endnotes and the data in Chapter 13 of USEPA's 1997 and 2011 EFH (USEPA 1997a, 2011).
There are substantial uncertainties associated with the LI and L2 parameters, including the wide
variation across produce types that were averaged together to create a mean value. For example,
the L2 factor does not distinguish between weight loss during cooking by water evaporation,
which could leave most of the chemical in the food, or by pouring the cooking liquid down the
drain, which would remove water-soluble chemicals and possibly lipid-soluble chemicals if oils
also are poured down the drain. The factor also does not distinguish cooking liquids used to
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
create sauces, because the sauce is not part of the food type consumed. The concentration of a
chemical might be highest in the skin (e.g., of fish, fruits, root vegetables) and lower in the
consumed fillet or bulky portion of many fruits and vegetables. Depending on the chemical,
discarding the skin can remove more of the chemical from ingestion than suggested by the
associated loss in weight. Finally, the data USEPA used to evaluate LI included negative losses
(i.e., weight gains) due to hydration of dried vegetables (e.g., peas and lima beans). Hydration
increases the range of LI values across different vegetables.
In contrast, the default LI and L2 values for fish are set to zero. That is because self-caught fish
ingestion rates are not the USDA's 1987 to 1988 NFCS (USDA 1993, 1994a) as reported in
USEPA's EFH, which reported food as brought into the home. Instead, MIRC includes fish IR
data based on actually consumed parts (e.g., fillet purchased from store, canned tuna). That
means there are no losses associated with fish preparation. A MIRC user can change fish
ingestion rates to match a local survey of the whole weight of fish brought into the home
(divided by number of persons consuming the fish) and set the LI and L2 parameters to non-zero
values. For this assessment of carcass management options, we assume all fish ingested are
caught in the on-site lake and set LI and L2 to zero.
Food Preparation/Cooking Adjustment Factor for Fish
Cooking also can induce changes in the concentrations of chemicals in fish. When chemical
concentration data comes from uncooked fish, the calculation must adjust for the chemical's
concentration in fish after cooking, because the fish consumption rates are "as consumed". To
account for this situation, MIRC can apply a food preparation/cooking adjustment factor
(FPCAF) to the data on concentration in uncooked fish to estimate a concentration in cooked
fish. The following subsections discuss FPCAFs for the four categories of chemicals in this
assessment.
Metals. Metals are assumed to bind to muscle and to be retained during the cooking process.
This assessment assumed that 0.33 of the moisture/fat in fish is lost during cooking and therefore
used a FPCAF of 1.5 for metals.
¦ Dioxins/furans. Dioxins are lipophilic and often are lost along with fats during cooking. This assessment used a
FPCAF of 0.7 to account for these losses during the cooking process. This value is not likely to overestimate
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
loss of PCDD/PCDFs from fish during cooking (pan frying, broiling, grilling). Reductions in TCDD concentrations
could be much higher with skin removal and trimming of fat. The research of Schecter et al. (1998), Reinert et
al. (1972), and Zabik and Zabik (1995) support use of that value: Schecter et al. (1998) reported the mass of
PCDD and PCDF in fresh catfish fillet (skin on) decreased by about 50% per serving portion during cooking.
Given the simultaneous losses of moisture/fats during broiling, the PCDDs and PCDFs concentrations
decreased by 33% (i.e., multiply uncooked concentration in fresh fish by a factor of 0.66 = 0.70 to one
significant digit).
¦ Reinert et al. (1972) reported higher losses of another highly lipophilic chemical, DDT, from cooking fish fillets
of bloaters, yellow perch, lake trout, and coho salmon. Concentrations of DDT in fish fillet portions for lake
trout and coho salmon, top predators, were reduced by 64 to 72% by frying or broiling, primarily through
preferential loss of fat (and lipophilic DDT) during cooking. The investigators did not report whether the skin
was on or off; however, they used steak cuts instead of flat fillets, which provide a smaller ratio of skin to
muscle than is the case for fillets that constitute one side of the fish. Finally, Zabik and Zabik (1995) quantified
the reduction in TCDD concentration of skinless cooked fillets compared with uncooked fillets (with skin).
Concentrations of TCDD in the skinless cooked fish relative to the raw fillet (with skin) were reduced by
approximately 44% for walleye, 80% for white bass, 61% for lake trout. TCDD concentrations were lower by
approximately 43% for Chinook Salmon cooked with the skin on versus 57% for chinook salmon cooked with
the skin off. They found a 37% reduction of TCDD concentration for carp fillets cooked with the skin on and a
54% reduction with the skin removed.
PAHs. While it is reasonable to assume there might be losses of lipophilic PAHs during the
cooking process, there is insufficient information to distinguish whether there is a net loss or gain
during cooking, because cooking can create PAHs from proteins in the tissue. The literature
acknowledges these competing forces, but does not provide sufficient information to disentangle
the gain and loss mechanisms. This assessment adopts a neutral approach by not assuming an
adjustment factor for PAHs in the modeling.
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
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Reinert, RE; Stewart, D; Seagran, HL. 1972. Effects of dressing and cooking on DDT
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Chlorinated dioxins and dibenzofurans in human tissue from general populations: a selective
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Stephens, R.D., M.X. Petreas, and G.H. Hayward. 1995. Biotransfer and bioaccumulation of
dioxins and furans from soil: Chickens as a model for foraging animals. Science Total
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USDA. 1993. Food and Nutrient Intakes by Individuals in the United States, 1 Day, 1987-88.
Nationwide Food Consumption Survey 1987-88, NFCS Report No. 87-1-1. (As cited in USEPA
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USD A. 2000. 1994-96, 1998 Continuing Survey of Food Intakes by Individuals (CSFII). CD-
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
USEPA. 2003 a. Chapter 10 In: Multimedia, Multipathway, andMultireceptor Risk Assessment
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
,. r.|">^ ;r 4 i \ , , Toxicity Reference Values
Some chemicals are more hazardous than others to humans, livestock, and aquatic and terrestrial
ecosystems. Some chemicals are of low toxicity even at high exposure concentrations (e.g., iron)
while others are of high toxicity at low doses (e.g., dioxins). Section 2.4.1 of the main report
presented the chemicals selected for the exposure assessment as well as those excluded from the
assessment and the reasons for their exclusion. For the chemicals included in the assessment, this
section summarizes the toxicity reference values (TRVs), human and ecological health and
welfare benchmarks, and other criteria that indicate the relative hazards posed by specified
chemical environmental concentrations and exposures.
Benchmarks by which to evaluate human exposures should be for the same route and duration of
exposure as the anticipated exposures of possible concern. For the livestock carcass management
options, two routes of exposure are relevant for humans: oral and inhalation. TRVs for chronic,
subchronic, and acute exposure durations were sought; however, benchmarks are not available
for some chemical and exposure duration combinations.
L.l. Benchmarks Used In Exposure Assessment (main report. Section
7)
Table L.l.l lists the TRVs for oral (ingestion) exposure to inorganic chemicals. Table L.l.2 lists
oral TRVs for two organic chemicals, BaP, and 2,3,7,8-tetrachlorodibenzodioxin (2,3,7,8-
TCDD). BaP is the index chemical for the RPF approach to evaluating polyaromatic
hydrocarbons (PAHs, see Appendix A). The compound 2,3,7,8-TCDD serves as the index
chemical for the toxicity equivalency factor (TEQ or TEF) for dioxins/furans (see Appendix B).
Cells shaded in grey indicate the values used in Section 7 of the main report.
Potentially harmful inhalation exposures could occur during the combustion phase of open-pyre
or air-curtain burning of carcasses, which is assumed to last approximately 48 hours. Table L.l.3
lists the TRVs for inhalation exposure to inorganic chemicals, and Table L.1.4 presents TRVs for
inhalation of BaP and 2,3,7,8-TCDD. Cells shaded in grey indicate the values used in Section 7
of the main report.
L-l
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
The sections that follow the first four tables (Sections L.2 through L.6) describe the human
TRVs and environmental concentration benchmarks in more detail.
L-2
-------
Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Table L.l.l. Toxicity Reference Values for Oral Exposure to Inorganic Chemicals.
Chemical
Arsenic,
Inorganic
Chronic
Oral
RID
(mg/kg
day)
3.00E-04
Chronic
Oral
RID
Ref
IRIS
Sub
chronic
Oral
RID
(mg/kg
day)
5.00E-03
Sub
chronic
Oral
RID
Ref
PPRTV
Archive
Short
term
Oral
RID
(mg/kg
day)
Acute
Oral
RID
(mg/kg
day)
5.00E-03
Acute
Oral
RID
Ref
ATSDR
Final
Oral
Slope
Factor
(mg/kg
day)1
1.50E+00
Oral
Slope
Factor
Ref
IRIS
Selected
Oral
Non
cancer
TRV
(mg/kg
day)
3.00E-04
6.7E-05
Cadmium
(Diet)
1.00E-03
IRIS
5.00E-04
ATSDR
Draft
5.00E-04
ATSDR
Draft
1.00E-03
Cadmium
(Water)
5.00E-04
IRIS
Chromium
(VP
3.00E-03
IRIS
3.00E-03
Copper
4.00E-02
HEAST
1.00E-02
ATSDR
Final
1.00E-02
ATSDR
Final
1.00E-02
ATSDR
Final
1.00E-02
Iron
7.00E-01
PPRTV
Current
7.00E-01
PPRTV
Current
7.00E-01
Lead and
Compounds
8.50E-03
CalEPA
1.2E-02
Manganese
(Diet)
1.40E-01
IRIS
1.40E-01
HEAST
1.40E-01
Manganese
(Non-diet)
2.40E-02
IRIS
recommends
subtracting
dietary
exposure
2.40E-02
Nickel
Oxide
1.10E-02
CalEPA
1.10E-02
Zinc and
Compounds
3.00E-01
IRIS
3.00E-01
ATSDR
Final
3.00E-01
ATSDR
Final
3.00E-01
Abbreviations: = not available; ATSDR = Agency for Toxic Substances and Disease Registry; CalEPA = California Environmental Protection Agency; HEAST = USEPA
Health Effects Assessment Summary Tables; IRIS = USEPA Integrated Risk Information System; PPRTV = Provisional Peer Reviewed Toxicity Values; Ref = reference; RID =
reference dose.
a The risk-specific dose represents the exposure dose corresponding to a target risk level of 10"4. The risk-specific dose is calculated by dividing the target risk level by the oral
slope factor.
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Table L.1.2. Toxicity Reference Values for Oral Exposure to Organic Chemicals.
Chemical
Chronic
Oral
RfD
Chronic
Oral
RfD
Ref
Sub
chronic
Oral
RfD
(mg/kg
day)
Sub
chronic
Oral
Short
term
Oral
RfD
(mg/kg
day)
Short
term
Oral
Acute
Oral
RfD
Acute
Oral
RfD
Ref
Oral
Slope
Factor
Oral
Slope
Factor
Ref
Selected
Oral
Non
cancer
Oral
Risk
Specific
Dose3
(mg/kg
day)
(mg/kg
day)
RfD
Ref
RfD
Ref
(mg/kg
day)
(mg/kg
day)1
TRV
(mg/kg
day)
Benzo[a]pyrene
-
-
-
-
7.30E+00
IRIS
-
1.4E-05
TCDD, 2,3,7,8-
7.00E-
10
IRIS
2.00E-08
ATSDR
Final
2.00E-
08
ATSDR
Final
2.00E-
07
ATSDR
Final
1.30E+05
CalEPA
2.0E-08
7.7E-10
Abbreviations: = not available; ATSDR = Agency for Toxic Substances and Disease Registry; CalEPA = California Environmental Protection Agency; IRIS = USEPA
Integrated Risk Information System; PPRTV = Provisional Peer Reviewed Toxicity Values; Ref = reference; RfD = reference dose.
a Hie risk-specific dose represents the exposure dose corresponding to a target risk level of 10"4. The risk-specific dose is calculated by dividing the target risk level by the oral
slope factor.
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Table L.1.3. Toxicity Reference Values for Inhalation Exposure to Inorganic Chemicals.
Chemical
Chronic
Inhal
RfC
(mg/m3)
Chronic
Inhal
RfC
Ref
Sub
chronic
Inhal
RfC
(mg/m3)
Sub
chronic
Inhal
RfC
Ref
Short
term
Inhal
RfC
(mg/m3)
Short
term
Inhal
RfC
Ref
Acute
Inhal
RfC
(mg/m3)
Acute
Inhal
RfC
Ref
Inhal
Unit
Risk
(jig/m3)1
Inhal
Unit
Risk
Ref
Selected
Inhal
Non
cancer
RfC
(jig/m3)
Derived
Inhal
Cancer
Risk
Specific
Conca
(jig/m3)
Arsenic,
Inorganic
1.50E-05
CALEPA
-
-
2.00E-04
CalFPA
4.30E-03
IRIS
1.5E-02
2.3E-02
Cadmium
1.00E-05
ATSDR
Final
9.00E-04
PPRTV
Archive
-
3.00E-05
ATSDR
Final
1.80E-03
IRIS
3.0E-02
5.6E-02
Chromium
(VI)
1.00E-04
IRIS; See
below
-
-
-
-
1.00E-01
Copper
-
-
-
1.00E-01
CalFPA
-
1.00E+0
2
Iron
-
-
-
-
-
-
Lead and
Compounds
-
-
-
-
1.20E-05
CalEPA
-
8.3E+00
Manganese
5.00E-05
IRIS
-
-
-
-
5.00E-02
Nickel
Oxide
6.00E-05
CALEPA
-
-
2.00E-04
CalEPA
2.60E-04
CalEPA
6.00E-02
3.8E-01
Zinc and
Compounds
-
-
-
-
-
-
Abbreviations: = not available; ATSDR = Agency for Toxic Substances and Disease Registry; CalEPA = California Environmental Protection Agency; Inhal = Inhalation; IRIS
= USEPA Integrated Risk Information System; PPRTV = Provisional Peer Reviewed Toxicity Values; Ref = reference; RfC = reference concentration.
a Hie risk-specific concentration represents the exposure concentration in air corresponding to a target risk level of 10"4. The risk-specific air concentration is calculated by dividing
the target risk level by the inhalation slope factor.
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Table L.1.4. Toxicity Reference Values for Inhalation Exposure to Organic Chemicals.
Chemical
Chroni
c
Inhal
RfC
(mg/m3)
Chronic
Inhal
RfC
Ref
Sub
chronic
Inhal
RfC
(mg/m3)
Sub
chronic
Inhal
RfC
Ref
Short
term
Inhal
RfC
(mg/m3)
Short
term
Inhal
RfC
Ref
Acute
Inhal
RfC
(mg/m3)
Acute
Inhal
RfC
Ref
Inhal
Unit
Risk
(pg/m3)1
Inhal
Unit
Risk
Ref
Selected
Inhal
Non
cancer
RfC
(pg/m3)
Derived
Inhal
Cancer
Risk
Specific
Conca
(pg/m3)
Benzo[a]-
pyrene
-
-
-
-
1.10E-03
CalEPA
-
9.1E-02
TCDD,
2,3,7,8-
4.0E-08
CALEPA
-
-
-
3.80E+0
1
CalEPA
4.0E-05
2.6E-06
Abbreviations: = not available; "CalEPA" = California Environmental Protection Agency; Inhal = Inhalation; Ref = reference; RfC = reference concentration.
a The risk-specific concentration represents the air exposure concentration corresponding to a target risk level of 10"4. The risk-specific dose is calculated by dividing the target risk
level by the inhalation slope factor.
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Section L.2 describes benchmark selection for such short-term inhalation exposures. Although
chronic releases of some gases (e.g., hydrogen sulfide) might continue for years, release rates
should be slow (e.g., less than a few cubic meters per day), and ambient air will substantially
dilute the gas concentrations; hence, chronic inhalation exposures are not evaluated.
For all livestock carcass management options, chemicals from the carcasses (and from auxiliary
materials included in carcass management) will remain onsite for years to decades, possibly
allowing chronic ingestion exposures via drinking water or foods grown on-site. Section L.3
describes benchmarks for the protection of human health and welfare that are expressed as
chemical concentrations in specific environmental media. Section L.4 describes TRVs for human
ingestion exposures expressed as doses for comparison with total chemical ingested from all
sources (e.g., drinking water, incidental soil ingestion, and consumption of foods grown on-site).
For environmental hazards that might arise from chemicals remaining from carcass management,
ecological benchmarks are described in Section L.5. Benchmarks for other types of effects or
hazards are discussed in Section L.6.
L.2. Air Concentrations—Short-term Human Health Benchmarks
The two on-site combustion options burn carcasses and auxiliary fuels over a 48-hr period. Thus,
an exposure benchmark expressed as an air concentration averaged over 48 hours would be most
suitable for comparison. Shorter limits, such as 1-hr or 8-hr average concentrations, might not be
adequately protective, and benchmarks based on longer averaging periods (e.g., annual) might be
overly conservative.
Chemical irritants show a strong inverse correlation between the duration of exposure and the
concentration of chemical tolerated. For example, for ammonia, USEPA's 1-hr acute exposure
guideline level (AEGL) 2 (which might result in long-lasting adverse health effects) is 160 ppm
(114 mg/m3), whereas the 8-hr AEGL 2 is 110 ppm (99 mg/m3). USEPA's 24-hr Provisional
Advisory Level (PALs) is lower, at 22 mg/m3, and its 30-day PAL is lower still, at 13.6 mg/m3.
Finally, USEPA's chronic reference concentration (RfC) for ammonia in IRIS is 0.1 mg/m3. In
other words, higher air concentrations can only be tolerated for shorter durations. It would not be
health protective to use a 1-hr or 8-hr AEGL 2 (i.e., 114 or 99 mg/m3, respectively) to evaluate a
48-hr exposure for ammonia. In fact a 48-hr exposure at 22 mg/m3 (the 24-hr PAL) might cause
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
adverse effects, whereas a 48-hr exposure at 13.6 mg/m3 ppm (the 30-day PAL) presumably is
safe. A 48-hr exposure at 0.1 mg/m3 (the chronic RfC) also should be safe, and in fact appears to
be overly conservative by approximately 2 orders of magnitude.
Non-irritant chemicals tend not to show a strong inverse relationship between inhalation
exposure duration and the highest concentration associated with no adverse health effects.
California EPA's (CalEPA) inhalation reference exposure level (REL) for repeated 8-hr
exposures for systemic effects of arsenic, for example, is the same as its lifetime chronic REL
(i.e., both are 1.5E-05 mg/m3), although its 1-hr REL is higher (i.e., 2.0E-04 mg/m3) (CalEPA
2014a,b).
Based on the considerations described above and based on USEPA's hierarchy of human health
toxicity values recommended for use in risk assessment for Superfund, a hierarchy of sources
was used to identify short-term inhalation exposure benchmarks for chemicals for this
assessment. USEPA sources were preferred, with CalEPA and ATSDR toxicity profiles
consulted in the absence of USEPA values (USEPA 2003). For USEPA sources, 24-hr and 30-
day PALs would be preferred over an IRIS chronic RfC or Superfund Provisional Peer-
Reviewed Toxicity Value (PPRTV); 10- and 30-minute and 1-, 4-, and 8-hour inhalation AEGLs
were not considered, because they might not be adequately protective over a 48-hr exposure
duration. USEPA PALs are based on other existing guidelines, however, and currently (May 2,
2016) are not available online. Oak Ridge National Laboratory (ORNL)'s Risk Assessment
Information System (RAIS; available online) was used to identify other existing guidelines.
When USEPA values were not available, and CalEPA or ATSDR "acute" inhalation benchmarks
were used instead. For these sources, the supporting toxicity studies were reviewed to determine
whether the identified benchmark is expected to be protective for a 48-hr exposure. For example,
CalEPA's repeated 8-hr REL for some chemicals is based on experiments with more than 60
hours of inhalation exposure, which is likely to be protective for a 48-hr exposure. A CalEPA 8-
hr REL for other chemicals might be based on experiments with as few as one or two 8-hr
exposures, in which case the REL might not be protective. CalEPA's Acute (1-hr) REL values
usually are be based on 30 to 90 minutes of exposure, which might not be protective for a 48-hr
exposure. ATSDR's "acute" minimal risk levels (MRLs), on the other hand, cover 1- to 14-day
exposures and often are derived from experiments ranging from 24 hours continuous exposure to
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
2 weeks intermittent inhalation exposure (e.g., 6.5 hr/day, 5 days/wk). Thus, an ATSDR acute
inhalation MRL is likely to be protective for a 48-hr exposure, but original toxicological profiles
were consulted to determine the basis of an acute inhalation MRL.
For chemicals considered carcinogenic via inhalation, air unit risk levels also were obtained and
used to calculate an air concentration associated with a lifetime risk of 1.0E-04. USEPA IRIS
was the preferred source, and CalEPA values were used where EPA values were not available. A
lifetime exposure corresponds to approximately 25,500 days (i.e., 70 years), and 48 hours
represents 0.00008% of a lifetime for humans; therefore, chemicals were not assessed for
carcinogenic risks from 48-hr inhalation exposures.
Table L.l.l, includes the inhalation benchmarks identified for inorganic chemicals evaluated in
this assessment. Several chemicals had only chronic values available (e.g., chromium,
manganese), while others had both short and longer-term inhalation benchmarks available (e.g.,
cadmium, nickel). No inhalation benchmarks were available for some chemicals (e.g., zinc,
iron). Table L. 1.2 includes the inhalation benchmarks for organic chemicals.
1-3. Benchmark Concentrations - Human Welfare
For chemicals that could migrate from livestock carcasses into soils and then to groundwater and
surface waters (e.g., from air deposition, leaching, erosion, runoff), several types of benchmarks
are applicable. USEPA Office of Water (OW) has developed two types of water concentration
benchmarks protective of human health: one set for ambient surface waters and another set for
drinking water.
National Ambient Water Quality Criteria (NAWQC). Under the Clean Water Act (CWA),
USEPA's OW develops NAWQC to protect human health (HH), aquatic life (AL), wildlife, and
uses of surface waters.28 One of the criteria to protect human health assumes daily consumption
of 2 liters of untreated water along with an average of 17.5 grams of fish caught in the surface
water and incidental water ingestion during recreation. That criterion is presented for the
NAWQC-HH in Table L.3.1.
28 http://water.epa.gov/scitech/swguidance/standards/criteria/current/index.cfm
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Table L.3.1. Concentrations in Water to Protect Human Health and Welfare.3
Chemical Agent
EPA Benchmark
Water Concentration (jig/L)
Metals
Arsenic
NAWQC-HH
MCL
0.018
10
Chromium (total)
MCL
100
Iron
NSDWR (to limit rusting/discoloration
porcelain/laundry)
300
Lead
Drinking Water Maximum Contaminant Action Levelb
15,000
Mercury
MCL
0.002
Zinc
NAWQC-HH
7,400
PAHs
Benzo[a]pyrene
MCL
0.2
Benzo [a] anthracene
Benzo [b]fluoranthene
Benzo [kjfluoranthene
Chrysene
NAWQC-HH
0.0038
Dibenzo [a,h] Anthracene
Ideno[l,2,3-cd]Pyrene
NAWQC-HH
0.018
Fluoranthene
NAWQC-HH
130
Fluorene
1,100
Dioxins/Furans
2,3,7,8-TCDD
NAWQC-HH
0.000000005 (5.0 10 9)
Other Chemicals and Measures
Nitrate (as N)
Nitrite (as N)
MCL
MCL
10,000
1,000
Sulfate
NSDWR (taste)
250,000
Chloride
250,000
Abbreviations: NAWQC = national ambient water quality criterion; HH = for the protection of human health; MCL = maximum
contaminant level; NSDWR = national secondary drinking water regulation.
a Values in bold are concentrations at or below 1 ppm (1 mg/L or 1,000 ng/L).
b Lead in drinking water is regulated by a treatment technique that requires systems to control the corrosiveness of the water. If
more than 10 % of tap water samples exceed the action level, water systems must take additional steps.
The other criterion is established for ingestion of fish only (assumes drinking water from a
different source), and is not included in Table L.3.1 because it generally is a less stringent value.
Both are based on USEPA's Reference Dose (RfD) or cancer slope (potency) factor (CSF) and
an associated risk of 1.0E-06. Thus, the NAWQC-HH for arsenic is lower than is needed to
target a risk of 1.0E-04 (see Section 7 of the main report).
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Maximum Contaminant Levels (MCLs). Under the Safe Drinking Water Act (SDWA), USEPA
OW develops MCLs and MCL Goals (MCLGs).29 The MCLs are National Primary Drinking
Water Regulations; they are legally enforceable standards that apply to public water systems
developed with both health (e.g., RfDs) and technological feasibility considered. The MCLGs
are not enforceable (for carcinogenic chemicals, MCLGs are zero). The MCL for arsenic is listed
in Table L.3.1 because theNAWQC-HH for arsenic is based on a 1.0E-06 risk, which is more
conservative than needed for the 1.0E-04 risk targeted in this assessment.
National Secondary Drinking Water Regulations (NSDWRs). USEPA OW also develops
NSDWR, which are non-enforceable guidelines based on aesthetic effects including taste, odor,
and color.
USEPA OW accounts for likely dietary exposures to a given chemical somewhat differently
when calculating MCLs and NAWQC-HH; therefore, MCLs and NAWQC-HH are not
necessarily the same. For chemicals with both an MCL and NAWQC-HH, the lower of the two is
presented in Table L.3.1 (except for arsenic for which both are listed).
JL.4. Ingestion Reference Doses
A hierarchy of sources was reviewed for chronic and subchronic oral RfDs, with EPA sources
(i.e., IRIS and PPRTV) preferred and ATSDR and CalEPA values checked for chemicals for
which USEPA RfDs could not be identified. Table L.4.1 presents the chronic RfDs and oral
CSFs for the chemicals that might deposit to soils, contaminate crops, livestock (and dairy
products), poultry (and eggs), or accumulate in fish. The relative oral toxicity of the chemicals
can be assessed with RfD values and oral CSFs without assuming specific exposure scenarios.
For PAHs, most of which are categorized as B2 carcinogens, meaning that evidence of
carcinogenicity in animals is adequate to conclude that they are likely human carcinogens, EPA
is developing a RPF approach to toxicity assessments. The approach facilitates estimating the
combined toxicity of mixtures of PAHs based on the relative concentrations of different
congeners (USEPA SAB 2011). BaP serves as the index chemical, and the carcinogenic potency
29 http://water.epa. ao v/dri nk/co nta m i na nt s/i ikIc.v c I'm# L i st
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
of other PAHs is estimated as a factor by which to multiply the BaP oral cancer slope factor.
RPFs for PAHs are listed in the last table in Appendix A.
For dioxins and furans, EPA has published its recommended toxicity equivalence factors (TEFs
or TEQs) with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) as the index chemical. All TEFs for
dioxins and furans are less than 1.0, meaning that 2,3,7,8-TCDD is the most toxic of the group
(USEPA 2010). The TEFs for the dioxin congeners are presented in the last table in Appendix B
For an exposure duration to be considered chronic, it must cover more than 10% of the animal's
lifespan. USEPA defines subchronic exposures for humans as lasting between two weeks to six
years. For the carcass management options, the highest exposure concentrations that might be
associated with leaching from buried carcasses or ash, for example, is likely to occur over the
first few months, with lower concentrations occurring over subsequent months and years. Thus,
it might be overly conservative to compare chronic RfDs with the average first month or first
year of exposure. Similar to the case for inhalation exposure (Section L.2), higher exposure
concentrations or doses might be acceptable over shorter time periods. However, all subchronic
RfDs identified for the chemicals evaluated were equal to the chronic RfD values
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Table L.4.1. Chronic Oral Reference Doses (RfDs).a
Chemical Agent
Chronic Oral
Reference Dose
(mg/kg day)
Source
Oral Slope Factor
(l/(mg/kg day))
Carcinogenic
Weight of
Evidenceb
Source
Arsenic (inorganic)
0.0003
IRIS
1.5
A
IRIS
Cadmium (diet)
0.001
IRIS
7 studies indicate
not carcinogenic via
oral exposure
not assessed
IRIS
Cadmium (water)
0.0005
IRIS
not assessed
IRIS
Chromium (VI)
0.003
IRIS
-
D
IRIS
Copper
0.04
HEAST
-
D
HEAST
Iron
0.7
PPRTV
Current
~
Information
inadequate to
assess
PPRTV
Lead
no threshold
IRIS
0.0085
B2
CalFPA
Manganese
0.14
IRIS
-
D
Divalent Mercury
0.0003
IRIS
-
not assessed
IRIS
Nitrates
1.6
IRIS
-
not available
IRIS
Nitrites
0.1
IRIS
-
not available
IRIS
Nickel Soluble
Salts
0.02
IRIS
-
not assessed
IRIS
Nickel Oxide
0.011
CalEPA
not evaluated for
oral carcinogenicity
Zinc
0.3
IRIS
-
D
PAHs
Benzo[a]pyrene
(index chemical
for PAHs)
not assessed
7.3
B2
IRIS
Other PAHs
not assessed
use RPFs
B2
EPA xxxx
Dioxins/furans
2,3,7,8-TCDD
(index chemical
for dioxins/furans)
0.0000000007
(7xlO-10)
cancer assessment
currently underway
Other
Dioxins/Furansc
use TEFs (=TEQs)
a IRIS is USEPA's Integrated Risk Information System. Values in bold are concentrations at or below 1 ppm.
b Weight-of-evidence (WOE) categories for carcinogens: A: Human carcinogen. B2: Probable human carcinogen - based on
sufficient evidence of carcinogenicity in animals. D: Not classifiable as to human carcinogenicity.
c TEFs are toxicity equivalency factors (USEPA 2010).
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L.5. Ecological Benchmarks
Ecological benchmarks expressed as concentrations in surface water (Section L.5.1) and as
concentrations in surface soils (Section L.5.2) were sought for the chemicals and secondary
characteristics associated with carcass management options.
L.5.1. Surface Water
Under the CWA, EPA OW also develops national ambient water quality criteria for the
protection of aquatic life (NAWQC-AL) and their uses. Criteria for many metals depend on
water characteristics such as hardness or pH. Criteria for chemicals that are major plant nutrients
vary by region of the country and sometimes by surrounding land uses. Measures of other water
characteristics important to sustaining aquatic life (e.g., dissolved oxygen) can vary by
temperature and region. Table L.5.1 presents NAWQC-AL organized in three categories. The
first group of chemicals includes the metals and other toxic chemicals. The second group
includes measures of water quality that represent the aggregate effect of the chemicals in water.
The last group includes the major nutrients that affect plant growth in surface waters (and on
land). Chemicals for which the benchmark is less than 1 mg/L (1,000 |ig/L) are highlighted in
bold. Table 5.4.5 in the main document presents numeric aquatic life criteria in the first data
column.
Table L.5.1. Concentrations in Ambient Surface Waters to Protect Aquatic Life.3
Chemical Agent
USEPA Benchmark
Water Concentration (jig/L)
Non-nutrient Chemicals
Arsenic
NAWQC-AL, criterion
continuous concentration
(CCC) (i.e., for chronic
exposures)
150
Chromium (III)
74
Chromium (VI)
11
Chloride
230,000
Copper
9.0
Iron
1,000
Lead
2.5
Nickel
52
Zinc
120
Mercury
770
H2S (tends not to partition to water)
2.0
Secondary Characteristics b
Biological Oxygen Demand (BOD)
NAWQC-AL for Dissolved
Oxygen
There are no federal criteria related
directly to BOD or COD, only oxygen
Chemical Oxygen Demand (COD)
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
Chemical Agent
USEPA Benchmark
Water Concentration (jig/L)
Total Dissolved Solids (TDS)
No federal criteria
Contributing ions: anions - carbonates,
chlorides, sulfates, nitrates; cations -
sodium potassium, calcium magnesium
Dissolved Oxygen
(four separate criteria)
30-day mean
7-day mean
7-day minimum
1-day minimum
NAWQC-AL cold water or
warm water and early or other
life stages (LS)
cold water warm water
earlvLS other LS earlvLS other LS
na 6,500 na 5,500
6,500 na 6,000 na
na 5,000 na 4,000
5,000 4,000 5,000 3,000
pH
NAWQC-AL CCC
6.5-9.0
Soluble Nutrients0
Ammonia-nitrogen (NH4-N)
NAWQC- AL-CCC varies by
ecoregion and enviromnental
conditions (e.g., pH,
temperature, season). See also
state-specific criteria.
1,900 |ig !L total ammonia-nitrogen
(TAN), pH = 7.0, 20°C
(30-dav rolline averaee)
Ammonium
Phosphorus (avg of 6 regions)
USEPA Region 4
USEPA Region 5
USEPA Region 8
USEPA Region 9
USEPA Region 12
USEPA Region 14
19
20
33
8
20
10
8
Total Nitrogen (avg of 6 regions)
USEPA Region 4
USEPA Region 5
USEPA Region 8
USEPA Region 9
USEPA Region 12
USEPA Region 14
474
440
560
240
360
520
320
Abbreviations: avg = average: BOD = biological oxygen demand ; CCC = criterion continuous concentration (i.e., chronic
criterion); COD = chemical oxygen demand; d = day; LS = lifestage na = not applicable; NAWQC-AL = national ambient
water quality criteria for the protection of aquatic life and their uses; TDS = total dissolved solids.
a Values in bold are sufficiently low to be of concern.
b Secondary characteristics (also known as water quality indicators) can be affected by decomposition products; they are not
specific chemicals that are released.
c For state and ecoregional adoption of EPA-approved nitrogen and phosphorus criteria, refer to
http://cfpub.epa.gov/wasits/nnc-development/
L.5.2. Soils
For soils, this assessment uses USEPA's Superfund Ecological Soil Screening Levels (Eco-SSLs)
as described in Section 5.4.2 of the main report. The Eco-SSLs are intended to screen chemical
concentrations in surface soils for potential impacts on wildlife, vegetation, and soil biota (e.g.,
earthworms, other soil invertebrates important to soil aeration and nutrient recycling). The Eco-
SSLs for soil invertebrates are primarily based on direct soil toxicity to earthworms, but other
soil-dwelling invertebrates (e.g., insect larvae) are sometimes tested. The mammalian Eco-SSLs
are based on indirect exposures of ground-feeding mammals ingesting soil invertebrates. They
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usually are backcalculated on the basis of shrews consuming earthworms and larval insects. The
avail Eco-SSLs also are based on indirect ingestion exposures and usually are back calculated on
the basis of woodcock consuming 100% earthworms. The Eco-SSLs for plants are based on
direct toxicity of soils to plants.
Table L.5.2. Ecological Soil Screening Levels.
Chemical
Ecological Soil Screening Levels (mg/kg)a
Invertebrates
Mammalian
Avian
Plants
Arsenic
-
4.6
43
18
Cadmium
-
-
-
-
Chromium
-
130
-
-
Copper
-
230
120
13
Iron
-
-
-
-
Lead
1700
56
11
120
Manganese
450
4000
4300
220
Nickel
280
130
210
38
Zinc
120
79
46
160
PAHs
-
-
-
-
Dioxin/ Furans
-
-
-
-
a Chemical-specific Eco-SSL reports can be found https://rais.onil.gov/documents/eco-ssl_fcheinicalJ.pdf. For example, the Eco-
SSL document for nickel can be found at https://rais.onil.gov/docunients/eco-ssl nickel.pdf. Also theoretically at
http://www.epa.gov/ecotox/ecossl/: however, that link seems to lead to ECOTOX only.
L.6. Other Adverse Effects
Methane Explosion. A highly flammable gas, methane becomes explosive in mixtures with
oxygen between a lower explosive limit (LEL) of 5% volume of methane/volume of air (v/v) and
an upper explosive limit (UEL) of 15% v/v. Methane concentrations above the UEL (> 15%/v)
are too rich (O2 levels are too low) to support combustion (USEPA 2005).
Odor Detection. Hydrogen sulfide (H2S) is one of the most odorous of the chemicals produced
by decaying carcasses, with concentrations as low as 0.008 ppm (0.01 mg/m3) producing a
detectably noxious odor (ATSDR 2014). It originates from anaerobic decomposition of
carcasses, and smells like rotten eggs. Ammonia, on the other hand, must reach approximately 50
ppm before humans can smell it (ATSDR 2004).
Eutrophication of Surface Waters. Excessive nutrient loading to surface waters over a relatively
short period of time (e.g., days, weeks) can cause serious algal blooms and growth of noxious
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
weeds, which can limit recreational uses of water and restrict areas suitable for fish. When algal
blooms die off, decomposition of the algal cells by bacteria often consumes sufficient oxygen to
cause fish kills. Thus, excessive nutrient loading can have adverse consequences for both
humans and aquatic organisms.
No single benchmark concentration for nutrient chemicals is applicable to all waters in all parts
of the country. In some locations, phosphorus might be the limiting nutrient while in other areas,
nitrogen might be. Additions of the limiting nutrient will foster plant growth, whereas addition of
the non-limiting nutrient might not cause an obvious effect. Regions with heavy agricultural land
use tend to develop problems when there is nutrient loading to surface waters from fertilizer
runoff. For livestock operations, runoff from manure also loads receiving waters with nutrients,
which can result in surface waters failing to attain some state-designated uses. Nutrient loading
from livestock carcass management could be compared with the nutrient loading from normal
livestock management operations to determine if it could be considered excessive.
JLT. References
ATSDR (2004). Toxicological Profile for Ammonia. Atlanta, GA: U.S. Department of Health
and Human Services, Public Health Service.
ATSDR (2014). Toxicological Profile for Hydrogen Sulfide / Carbonyl Sulfide (Draft for Public
Comment). Atlanta, GA: U.S. Department of Health and Human Services, Public Health Service.
CalEPA (California Environmental Protection Agency) (2014a). OEHHA (Office of
Environmental Health Hazard Assessment) List of Acute, 8-hr, and Chronic Reference Exposure
Level (REL)s. Retrieved April 25, 2016, from http://oehha.ca.uov/air/allrels.html.
CalEPA (2014b). Technical Support Document for Noncancer RELs (December 2008, Updated
July 2014). Appendix D. Individual Acute, 8-Hr, and Chronic Reference Exposure Level
Summaries. Appendix Dl. Summaries using this version of the Hot Spots Risk Assessment
guidelines.
USEPA (2010). Recommended Toxicity Equivalence Factors (TEFs) for Human Health Risk
Assessments of 2,3,7,8-Tetrachlorodibenzo-p-dioxin andDioxin-Like Compounds. Risk
Assessment Forum, Washington, DC. EPA/600/R-10/005.
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Exposure Assessment of Livestock Carcass Management Options During Natural Disasters - Appendices
USEPA (2005). Guidance for Evaluating Landfill Gas Emissions from Closed or Abandoned
Facilities. Washington, DC: Office of Research and Development. Report No. EPA-600/R-
05/123a. Retrieved March 20, 2015 from:
https://cfpub.epa.gov/si/si public record report.cfm?dirEntrvld= 137824
USEPA (2003). Human Health Toxicity Values in Superfund Risk Assessments. Memorandum
from Michael B. Cook, Director, Office of Superfund Remediation and Technology Innovation,
to Superfund National Policy Managers, Regions 1-10. OSWER Directive 9285.7-53.
December 5. Retrieved April 25, 2016, from https://semspub.epa.gov/work/03/2218797.pdf
USEPA SAB (Science Advisory Board) (2011). SAB Review of EPA's "Development of a
Relative Potency Factor (RPF) Approach for Polycyclic Aromatic Hydrocarbon (PAH) Mixtures
(February 2010 Draft). Memorandum from D.L. Swackhamer and N.K. Kim to Administrator
L P. Jackson. March 17. EPA-SAB-11-004.
https://yosemite.epa.gOv/sab/sabproduct.nsf/0/F24FBBB AC A6EEABA852578570040C547/$Fil
e/EPA-SAB-1 l-004-unsigned.pdf
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