&EPA
United States
Environmental Protection
Agency
Office of Toxic Substances
TS-792
EPA 560/5-90-011
July 1990
Integrated Risk
Assessment for
Dioxins and Furans
from Chlorine Bleaching
in Pulp and Paper Mills
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EPA 560/5-90-011
July 1990
Project Officer
Thomas M. Murray
Exposure Evaluation Division
Exposure Assessment Branch
401 M Street, SW
Washington, DC 20460
U.S. Environmental Protection Agency
Office of Pesticides and Toxic Substances
Washington, DC 20460
July 1990
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11
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DISCLAIMER
This document has been reviewed and approved for publication by the
Office of Toxic Substances, Office of Pesticides and Toxic Substances,
U.S. Environmental Protection Agency. The use of trade names or
commercial products does not constitute Agency endorsement or
recommendation for use.
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TABLE OF CONTENTS
EXECUTIVE SUMMARY
INTRODUCTION
1.1
1.2
1.3
Purpose
Background
1.2.1 Nature of the Probl em
1.2.2 Di scovery of the Probl em
1.2.3 Federal Response
1.2.4 Consent Decree
Scope and Organization of the Integrated Risk
Assessment
INTEGRATED RISK ASSESSMENT
2.1
2.2
2.3
2.4
2.5
Common Assumptions
Summary of the Chemistry and Fate of 2,3,7,8-TCDD
and 2,3,7,8-TCDF
2.2.1 Chemistry and Fate of 2,3,7,8-TCDD
2.2.2 Chemistry and Fate of 2,3,7,8-TCDF
Summary of Hazard Assessment for TCDD/TCDF
2.3.1 Human Hazard Assessment
2.3.2 Aquatic Organism Hazard Assessment
2.3.3 Wildlife Hazard Assessment
Summary of Ri sks to Workers
2.4.1 Introduction
2.4.2 Methodol ogy
2.4.3 Results and Discussion
Summary of Risks Resulting from Use and Disposal
of Pulp and Paper Mill Sludge and Land Disposal of
Paper
2.5.1 Introduction
2.5.2 Methodology
2.5.3 Results and Discussion
Paae No.
viii
1
1
1
1
2
3
5
5
7
7
9
10
10
12
12
15
16
17
17
* 18
18
24
24
25
32
iv
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TABLE OF CONTENTS (continued)
Page No.
2.6 Summary of Risks to Humans from Wastewater
Discharges 33
2.6.1 Introduction 33
2.6.2 Methodology 34
2.6.3 Results and Discussion 35
2.7 Summary of Risks Resulting from Pulp and Paper Mill
Sludge Incineration 38
2.7.1 Introduction 38
2.7.2 Methodology 38
2.7.3 Results and Discussion 39
2.8 Summary of Risks Resulting from Use of and Consumer
Body Contact with Paper Products Under CPSC
Jurisdiction 41
2.8.1 Introduction 41
2.8.2 Methodology 41
2.8.3 Results and Discussion 44
2.9 Summary of Risks Resulting from the Use of Pulp-
Containing Medical Devices Under FDA Jurisdiction .. 44
2.9.1 Introduction 44
2.9.2 Methodology 46
2.9.3 Results and Discussion 46
2.10 Summary of Risks from Ingestion of Foods Contacting
or Packaged in Bleached Paper Products 50
2.10.1 Introduction 50
2.10.2 Methodology 50
2.10.3 Results and Discussion 54
2.11 Summary of Risks from Use of Food, Drug, and Cosmetic
Products Containing Cellulose Derivatives 56
2.11.1 Introduction 56
2.11.2 Methodology 57
2.11.3 Results and Discussion 59
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TABLE OF CONTENTS (continued)
Page No.
2.12 Summary of Risks to Wildlife from Land Application
of Sludge and to Aquatic Life from Discharge of
Effluents 59
2.12.1 Introduction 59
2.12.2 Methodology 61
2.12.3 Results and Discussion 63
2.13 Summary of Toxicity, Environmental Releases, and
Effluent Concentrations of Other Chlorinated
Organics 70
3. REFERENCES 72
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LIST OF TABLES
Page No.
Table E-l Summary of Reasonable Worst Case Individual
Cancer Risks Exceeding 10"6 xiv
Table 1. Summary Results of the 104-Mill Study 4
Table 2. Summary of Environmental Fate of 2,3,7,8-TCDD .... 11
Table 3. Summary of Environmental Fate of Dibenzofurans ... 13
Table 4. Summary of Individual and Population Cancer Risks
for Workers Involved in Manufacturing, Processing,
and Commercial Usage of Pulp, Paper, and Paper
Products 19
Table 5. Summary of Individual and Population Cancer Risks
for Workers Involved in Processing and Commercial
Usage of Pulp and Paper Mi.ll Sludge 22
Table 6. Distribution of 2,3,7,8-TCDD and 2,3,7,8-TCDF
Sludge Concentrations for All Plants in the
104-Mill Study 26
Table 7. Use and Disposal Methods for Pulp and Paper Mill
Sludge 27
Table 8. General Population Cancer Risks Estimated Using
Generic Exposure Scenarios Associated with Each
Pulp and Paper Mill Sludge Management Practice
and wi th Di sposal of Paper Wastes 28
Table 9. Estimated Cancer Risks Associated with Consumption
of Contaminated Fish 36
Table 10. Combined Dioxin/Furan Risks and Annual Incidence . 40
Table 11. Individual Lifetime and Population Cancer Risks
from 2,3,7,8-TCDD and 2,3,7,8-TCDF in Consumer
Paper Products 42
Table 12. Risks of Non-Cancer Adverse Effects from 2,3,7,8-
TCDD and 2,3,7,8-TCDF in Consumer Paper Products.. 45
Table 13. Exposure/Risk Parameters for Medical Devices . 47
Table 14. Estimates of Cancer Risks to the General Population
from the Use of Pulp-Containing Medical Devices .. 48
vii
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LIST OF TABLES (continued)
Page No.
Table 15.
Table 16.
Table 17.
Table 18.
Table 19.
Table 20.
Carcinogenic Risk for Consumers Resulting from
Total Dioxin TEQ Intake from all Foods Contacting
Bleached Paper ("mean consumer - total sample
basis) ,
Upper Bound Carcinogenic Risk for Consumers of Foods
Containing Bleached Paper Contaminated with Dioxin
("eaters only - food-by-food basis")
Upper Bound Carcinogenic Risk for Users of Food,
Drug, and Cosmetic Products Containing Cellulose
Derivatives
Estimates of Exposure and Risk to Mammals from
2,3,7,8-TCDD in Sludge-Treated Land
Estimates of Exposure and Risk to Adult and Hatch-
ing Birds from 2,3,7,8-TCDD in Sludge-Treated
Land
Results of Preliminary Search for Endangered (E)
and Threatened (T) Species Found in the Counties
Where Pulp and Paper Mills Are Located That Apply
Dioxin- and Furan-Contaminated Pulp and Paper Mill
SIudge to Land
51
52
60
64
66
68
viii
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ACKNOWLEDGMENTS
This risk assessment was a cooperative Federal agency effort
involving the United States Environmental Protection Agency (EPA), the
Food and Drug Administration (FDA), and the Consumer Product Safety
Commission (CPSC). Dwain Winters of the EPA Office of Toxic Substances
(OTS) served as coordinator of the Interagency Working Group on Dioxins
in Bleached Wood Pulp. Dr. Robert Scheuplein and Dr. Melvin Stratmeyer
served as the FDA representatives to this Working Group; Sandra Eberle
and Dr. Andrew Ulsamer served as the CPSC representatives. The support
and management guidance provided by these individuals is gratefully
acknowledged.
The Interagency Working Group risk assessment activities were
coordinated by EPA-OTS. Lois Dicker served as Chair of the Interagency
Risk Assessment Workgroup and James Kwiat served as the Assistant Chair.
Versar Inc. of Springfield, Virginia served as the prime contractor
through EPA Contract No. 68-D9-0166 (Tasks 1 and 34). The EPA-OTS Task
Manager for this effort was Patricia Jennings and the EPA Program Manager
was Thomas Murray.
A number of Versar Inc. personnel have contributed to this task over
the period of performance, as shown below:
Program Management Gayaneh Contos
Task Management Greg Schweer
Technical Support Bentley Gregg
Patricia Wood
Timothy Leighton
Carl D'Ruiz
Arthur Clarke
Editing Martha Martin
Secretarial/Clerical Sally Gravely
Lynn Maxfield
Susan Perry
Kammi Johannsen
The contribution provided by each of these individuals is gratefully
acknowledged.
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A number of individuals on the Interagency Risk Assessment Workgroup
for Dioxin in Bleached Wood Pulp have served in key roles in completing
or managing efforts on the source documents upon which this Integrated
Risk Assessment is based. For each major subsection of this Integrated
Risk Assessment, the key individuals and the organization to which they
belong are identified:
Section 2.2:
Section 2.3:
Section 2.4:
Section 2.5:
Christina Cinalli, EPA Office of Toxic Substances
Cheng-Chun Lee, EPA Office of Toxic Substances
Nhan Nguyen, EPA Office of Toxic Substances
George Heath, EPA Office of Toxic Substances
Patricia Jennings, EPA Office of Toxic Substances
Priscilla Halloran, EPA Office of Solid Waste
Section 2.6: Stephen Kroner, EPA Office of Water Regulations and Standards
Section 2.7: Michael Dusetzina, EPA Office of Air Quality Planning and Standards
Michael Babich, CPSC Directorate for Health Sciences
Section 2.8:
Section 2.9:
Christina Cinalli, EPA Office of Toxic Substances
Donald Galloway, FDA Center for Devices and Radiological Health
Section 2.10: Gregory Cramer, FDA Center for Food Safety and Applied Nutrition
Michael Bolger, FDA Center for Food Safety and Applied Nutrition
Section 2.11: Gregory Cramer, FDA Center for Food Safety and Applied Nutrition
Michael Bolger, FDA Center for Food Safety and Applied Nutrition
Section 2.12: Gregory Cramer, FDA Center for Food Safety and Applied Nutrition
Michael Bolger, FDA Center for Food Safety and Applied Nutrition
Section 2.13: Robert Morcock, EPA Office of Toxic Substances
The efforts on behalf of the Integrated Risk Assessment by the Quantitative
Risk Assessment Committee (QRAC) of FDA's Center for Food Safety and Applied
Nutrition are also acknowledged. The members of the QRAC are as follows:
Sara Hale Henry (Executive Secretary) Linda R. Tollefson
Ronald J. Lorentzen (Co-Chair) Benjamin A. Jackson
Janet A. Springer (Co-Chair) Patricia S. Schwartz
Robert N. Brown Christine J. Lewis
Robert J. Scheuplein Paul M. Kuznesof
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Many members of the Interagency Risk Assessment Workgroup on Dioxins
in Bleached Wood Pulp whose names have not been mentioned previously
provided helpful comments and suggestions on the Integrated Risk
Assessment. The efforts of these individuals, listed below, are greatly
appreciated:
Ernest Falke, EPA Office of Toxic Substances
Patrick Kennedy, EPA Office of Toxic Substances
Julie Lyddon, EPA Office of Toxic Substances
Maurice Zeeman, EPA Office of Toxic Substances
David Cleverly, EPA Office of Technology Transfer and Regulatory Support
Susan Norton, EPA Office of Health and Environmental Assessment
Jacqueline Moya, EPA Office of Health and Environmental Assessment
Tom Hale, EPA Office of Policy Analysis
Jennie Helms, EPA Office of Water Regulations and Standards
Harold Podall, EPA Office of Toxic Substances
Gary Grindstaff, EPA Office of Toxic Substances
Alexander McBride, EPA Office of Solid Waste
Wardner Penberthy, EPA Office of Toxic Substances
Alan Rubin, EPA Office of Water Regulations and Standards
William Rabert, EPA Office of Toxic Substances
Robert Lipnick, EPA Office of Toxic Substances
Murray Conn, CPSC Directorate for Health Sciences
Patricia Szarek, EPA Office of Toxic Substances
Fred DiCarlo, EPA Office of Toxic Substances
Susan Griffin, EPA Office of Solid Waste
John Rigby, EPA Office of Toxic Substances
Paul White, EPA Office of Health and Environmental Assessment
Kim Hoang, EPA Office of Health and Environmental Assessment .
Anne Sergeant, EPA Office of Health and Environmental Assessment
Gary Foureman, EPA Office of Toxic Substances
Ann Clevenger, EPA Office of Toxic Substances
Jennifer Seed, EPA Office of Toxic Substances
Ivan Boyer, FDA Center for Food Safety and Applied Nutrition
Michael Adams, FDA Center for Food Safety and Applied Nutrition
Janet Remmers, EPA Office of Toxic Substances
Daljit Sawhney, EPA Office of Toxic Substances
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EXECUTIVE SUMMARY
Introduction
This report presents the key findings, assumptions, and uncertainties
of an assessment of risks from exposure of humans, terrestrial and avian
wildlife, and aquatic life to dioxins and furans formed during chlorine
bleaching at kraft and sulfite pulp and paper mills. The report provides
condensed versions of eight major exposure/risk assessments and other
support documents prepared by program offices within the U.S. Environment-
al Protection Agency (EPA), the U.S. Food and Drug Administration (FDA),
and the U.S. Consumer Product Safety Commission (CPSC). Risks were
evaluated from roughly 120 potential pathways of exposure to pulp and
paper products, pulp and paper mill sludges, and pulp and paper mill
effluents. The development of this assessment and the individual Agency
exposure/risk assessments were coordinated by the Federal Interagency
Working Group on Dioxin-in-Paper. The Background Document to this
Integrated Assessment contains detailed summaries of the individual
exposure/risk assessments.
j
Scope of Assessment
Because 2,3,7,8-TCDD is the most potent carcinogen evaluated to date
by EPA, a major focus of the Integrated Assessment is the assessment of
cancer risks. All of the major source documents prepared for the
Integrated Assessment estimated individual lifetime cancer risks. Some,
but not all, of the source assessments also estimated exposed population
sizes and resulting population risks and subpopulation risks. Population
risks were calculated in the following source reports:
Worker exposure/risk;
Risks from use and disposal of sludge;
Risks from incineration of sludge; and
Risks from use of consumer body contact papers.
Population risks were not estimated in the following source reports:
Risks from discharge of effluents;
Risks from use of medical devices;
Risks from use of food paper packaging and cellulose food
additives; and
Risks from use of cellulose additives in cosmetic products.
xii
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However, estimates of sizes of potentially exposed populations were
provided in the medical devices report, and comparison of the predicted
risks with the estimated population sizes indicates minimal population
risks (less than 0.005 cancer incidence/year for any product). Although
FDA did not estimate exposed population sizes, it can be presumed that
tens of millions or more people are exposed to the risks estimated for
food paper packaging/cellulose food additives and cellulose additives in
cosmetic products. Neither EPA nor FDA have reliable estimates of the
size of potentially exposed subsistence and sports fisher populations
that may be exposed to effluent discharges from pulp and paper mills.
EPA has contacted regional and state officials and has confirmed that
commercial, sport, and subsistence fishing does occur downstream from
several mills. However, scant information is available on sizes or
characteristics of these populations. Because information is lacking on
potentially exposed populations eating contaminated fish near the mills,
EPA has initiated a program to develop a uniform methodology to estimate
these populations at elevated risk.
Human risks of non-cancer effects resulting from long-term, low-level
exposures and relatively brief exposures to media such as contaminated
fish were also examined.
Results and Discussion
Table E-l presents a listing of all exposure scenarios addressed in
the Integrated Assessment for which the estimated reasonable worst-case
individual cancer risks exceeded 10"6 based on EPA's slope factor. The
range of risks presented in Table E-l for any given exposure pathway span
at least an order of magnitude because the range reflects, in part, the
differences in cancer slope factors used by EPA, FDA, and CPSC for
2,3,7,8-TCDD. Although the agencies' differences with respect to
selection of animal data and details of extrapolation of animal data to
humans result in risk estimates that differ by nearly an order of
magnitude, the agencies agreed that this Integrated Assessment would
report cancer risk estimates calculated using each agency's slope factor.
For some exposure pathways in Table E-l, the range of risks spans
more than an order of magnitude. The source(s) of this additional
variability is discussed below for each pathway where appropriate.
The results in Table E-l indicate that the following types of
individuals may be at significant risk:
Soort and subsistence fishers - 2,3,7,8-TCDD and 2,3,7,8-TCDF
have been positively identified in fish collected downstream from
many pulp and paper mills. Although not yet well characterized,
sports and subsistence fishers are known to be using some of these
waters. State agencies have issued public health advisories
warning against any consumption of fish or recommending limited
consumption for many of these water bodies. For this risk
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8941H-25
Table £-1. Summary of Reasonable Worst-Case Individual Cancer Risks Exceeding 10
Source
Effluent discharge
Pathway
Ingest ion of fish3
(EPA site-specific)
Ingest ion of fish
(FDA generic)
Exposed Upper bound individual lifetime cancer risk
Individuals >10"1 10~2 10"3 10~4 10"5 10"6 <10"7
~ 1 1 I I 1 1 T
Subsistence fishers
Sludge disposal
(occupational)
Sludge disposal
(ambient)
Ingest ion of water
Dermal contact w/sludge
or sludge-amended soil
Inhalation of
particulates
Inhalation of vapors
Dermal contact w/sludge-
amended so i1
Ingest ion of sludge-
amended soil
Individuals near mills
Pulp mill WWT workers
Lapd disposal workers
Land disposal workers
Land disposal workers
.Gardeners/subs i stence
farmers
Gardeners/subs i stence
fanners
Ingest ion of food
produced on sludge-
amended soil
Gardeners/subs i stence
farmers
Pulp/paper manuf.
(occupational)
Inhalation of
particulates
Inhalation of vapors
Ingestion of fish
contaminated by runoff
from land disposal and
land application sites
Ingestion of water
contaminated by runoff
from land disposal and
land application sites
Inhalation of
particulates
Individuals near land
application sites
Individuals near land
application sites
Individuals near land
disposal and land
application sites
Individuals near land
disposal and land
application sites
Paper mill workers
Paper converting workers
Nonwoven operations
workers
xiv
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8941H-26
Table E-l. (continued)
Exposed Upper bound individual lifetime cancer risk
Source
Pathway Individuals >10"1 10"2
1 1
ID'3
1
1C'4
1
lO'5
1
ID'6
1
<10'7
1
Paper food-contact
(general pop.)
Dermal contact w/
pulp/paper
Ingest ion of food
Cellulose food
additives
Ingest ion of food
Pulp mill workers
Paper mill workers
Paper converting workers
Users of paper cartons:
Milk
Juice
Ice cream
Bakery
Users of ovenable board:
Meals-seas, meat, veg.
Users of cup stock:
Coffee
Soup
Users of plates
Users of coffee filters
Users of tea bags
Users of microwave
popcorn
Users of butter wraps
Users of "all foods"
Users of high-fiber bread
Users of tablet binders
Users of laxatives
As discussed on pages xiii and xvi, EPA performed site-specific modeling assessments for each mill in the 104-Mill Study
that discharges to receiving streams for which flow data were available. The wide range of estimated risks for each of
the types of consumers reflects the range in risks estimated across the sites. Variability between the risks for these
types of consumers is the result of different bioconcentration factors and fish consumption rates that were assumed.
As discussed on pages xiii and xvi, FOA used monitoring data levels of 2,3,7,8-TCOD and 2,3,7,8-TCOF in the edible
portion of fish collected near pulp and paper mills to assess potential risks. The variability between the risks for
these two types of consumers is the result of different fish consumption rates that were assumed.
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assessment, two general approaches were used to estimate potential
individual cancer risks: surface water modeling (EPA) and fish
tissue monitoring data (FDA). Results are presented in Table E-l
for both approaches; risks for several types of consumers (i.e.,
average, sports fishers, and subsistence fishers) were estimated
to reflect the range of uptake of 2,3,7,8-TCDD and 2,3,7,8-TCDF by
fish and the range of possible fish consumption rates, the wide
range in risks estimated using the effluent modeling approach,
>_ 10"1 to 10"7, reflects differences in effluent concentrations of
2,3,7,8-TCDD and 2,3,7,8-TCDF, effluent flows, and receiving
stream flows at sites that were modeled. The use by FDA of
available monitoring data on residues of dioxin TEQs in the edible
tissues of fish collected near pulp and paper mills (mean and
maximum values across all sites) results in estimates of risks
ranging from 10"3 to 10"5, using all three slope
factors.
Persons obtaining drinking water immediately downstream from
pulp and paper mills - This exposure scenario assumes that
individuals are actually drinking untreated water immediately
downstream from these mills. However, data to document this
assumption are currently not available. A preliminary survey of
EPA drinking water data bases indicates that there are no major
public drinking water utilities (i.e., serving 5,000 or more
people) immediately downstream from any mill but that there are
some within 100 miles of some of the 104 pulp and paper mills. The
wide range in risks estimated in this assessment, 10~4 to .<. 10~7,
reflects differences in effluent concentrations of 2,3,7,8-TCDD
and 2,3,7,8-TCDF, effluent flows, and receiving stream flows at
sites that were modeled. It should be noted that this assessment
assumed, as a worst case, that all 2,3,7,8-TCDD/TCDF discharged
remains in the water column and is not removed during drinking
water treatment.
Workers who handle sludge - The results in Table E-l indicate
that workers in pulp and paper mill wastewater treatment plants
involved in sludge handling, as well as workers involved in
subsequent disposal of sludge via land disposal, could be at risks
ranging from 10~4 to 10"6 if the sludge contains dioxin toxic
equivalents (TEQs) at the maximum concentration found in the
104-Mill Study. It should be noted that the extent of use and
effectiveness of personal protective equipment and engineering
controls in this industry are not well known. Therefore, the
assessment assumed no use of protective equipment (e.g., gloves
and respirators) that could minimize potential exposures.
Similarly, the frequency and duration of potential dermal and
inhalation exposures were not well characterized. Reasonable
worst-case assumptions were used for these parameters in the
assessment.
xv i
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Gardeners/subsistence farmers using sludge-amended soil - These
individuals could be at risks ranging from 10~4 to 10"6
from inhalation, dermal contact, and direct soil ingestion if the
sludge contains 469 ppt of dioxin TEQs (i.e., the 90th percentile
TEQ concentration from the 104-Mill Study). Subsistence farmers
relying to a major extent upon meat, produce, and dairy products
produced on sludge-amended soil could be at risks ranging from
1CT2 to 10'3.
Persons obtaining drinking water and ingesting fish from water
bodies downstream from pulp and paper mill sludge land disposal
and land application sites - Runoff from land application sites
and from poorly managed land disposal sites into small water
bodies could result in risks ranging from >, 10"1 to 10"3
to consumers of fish and water from those water bodies if the
sludge contains 469 ppt of dioxin TEQs (i.e., 90th percentile TEQ
concentration from the 104-Mill Study). However, no data are
currently available to EPA to establish that poor sludge management
practices are followed at any specific land disposal sites.
Pulp and paper manufacturing workers - Depending upon the nature
of their work duties, certain workers could be at risks as low as
10*5 from dermal contact with pulp/paper and as low as
10"3 from inhalation of particulate matter. As was the case
for assessing risks to workers who handle sludge (above), this
assessment assumed no use of personal protective equipment.
Consumers of food packaged in or contacting bleached paper -
Millions of people could be at risks as high as 10"5 from
the migration of dioxin from paper packaging into food during
storage or food preparation activities if the paper contains
dioxin TEQs at the average level found in the 104-Mill Study.
Consumers of food and drug products containing cellulose
derivatives - Millions of people could be at risks as high as
10"6, if the cellulose derivatives contain dioxin TEQs at
the average level found in the 104-Mill Study.
Although specific population sizes were not estimated for the types
of individuals listed above, it can reasonably be assumed that more than
1 cancer incidence per year could be expected for several of these types
of individuals. Populations exposed to effluent discharge could exceed
one cancer case per year by virtue of the very high individual risks.
Populations exposed to food packaging and cellulose derivatives exceed
one cancer case per year because of the large numbers of individuals
exposed (tens of millions).
Estimation of risks of non-cancer effects indicated that effluent
discharges from 27 percent of mills could cause toxic liver effects with
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one 4-ounce serving of fish caught immediately downstream from the mills,
based on a 1-day health advisory dose of 100 pg/kg/day and assuming an
effective BCF of 50,000 for edible tissues; even more mills discharged
effluents that may cause reproductive effects from long-term, low-level
exposure, based on a reference dose of 1 pg/kg/day. Similarly, an FDA
analysis indicated that subsistence fishers could be at risk for
reproductive effects.
Summary of Estimated Risks to Aquatic Organisms and Terrestrial
Wildlife
Risks to Aquatic Organisms
It was assumed for the purpose of this assessment that concentrations
of 2,3,7,8-TCDD in water greater than 0.038 pg/1 will exhibit toxic
effects to some aquatic species. Applying the same approach to
2,3,7,8-TCDF, a concentration greater than 0.41 pg/1 was assumed to
exhibit toxic effects for some aquatic species. Water column
concentrations of 2,3,7,8-TCDD immediately downstream from 89 percent of
the mills evaluated were estimated to exceed 0.038 pg/1 under low stream
flow (7Q10) conditions. Water column concentrations of 2,3,7,8-TCDF
immediately downstream from 82 percent of these mills were estimated to
exceed 0.41 pg/1 under 7Q10 conditions.
Risks to Terrestrial Wildlife
This assessment did not attempt to quantify the effects of 2,3,7,8-
TCDD and 2,3,7,8-TCDF on populations or ecosystems. However, the results
of the assessment show that at certain sites where sludge is land applied,
the reproductive capability of individuals of certain terrestrial species
may be affected, assuming that wild species are at least as sensitive to
the effects of 2,3,7,8-TCDD and 2,3,7,8-TCDF as laboratory species.
Species that ingest prey items such as earthworms (which bioconcentrate
dioxins) are particularly at risk. Effects on the reproductive capability
of a sufficient number of individual members of a species may lead to
overall population effects for that species in that area, but no assess-
ment of population effects was performed.
Potential for Aggregate Risk
In general, this assessment focused on estimating risks for single
exposure pathways. It must be noted, however, that some individuals or
subpopulations can be exposed from more than one source of dioxins and
furans originating from bleached kraft pulp and paper mills. Under such
circumstances, the risks estimated would be summed and those individuals
or subpopulations would be at higher risk than other individuals or
subpopulations. The potential for aggregate risks to be of greatest
concern exists for those individuals or specific subpopulations that
xviii
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(1) live in the vicinity of and/or work at bleached kraft pulp and paper
mills; (2) live or work in areas where pulp and paper mill sludge is
land-applied; and (3) consume unusually large amounts of several
different foods contaminated with dioxins and furans as a result of
contact with or packaging of food in bleached paper.
Uncertainties and Conclusions
The Integrated Assessment identified the following risks of concern:
Risks to humans from food packaging;
Risks to terrestrial and avian organisms from land-spreading of
pulp and paper mill sludge;
Risks to humans and aquatic organisms from effluent; and
Risks to humans and wildlife from land-applied pulp and paper
mill sludge runoff.
The assessment also identified the following risks of possible concern:
Risks to workers who handle pulp and paper mill sludge, and
Risks to subsistence farmers from land-applied pulp and paper
mill sludge.
As in other assessments of risk, this assessment contains
uncertainties connected with the establishment of the health hazards and
with the development of exposure scenarios. For example, it is
recognized that there are legitimate differences of opinion within the
international scientific community regarding the quantification of the
cancer risk to humans from dioxins/furans. This is an area of continuing
research and reappraisal. Future epidemiological and pharmacokinetic
studies will hopefully answer the major question of the extent of CDD/CDF
toxicity to humans. Since CDDs/CDFs are known to readily bioconcentrate
in tissues of animals and humans and to have a long half-life in the body
(7-10 years), it appears reasonable to use a conservative approach in
considering the potential health risks of these chemicals.
Since EPA, FDA, and CPSC use a linear low-dose model for cancer risk
estimation, it should be emphasized that the individual cancer risk is
expressed as an upper bound limit, meaning that the risk will not likely
be higher than the upper bound, but could be as low as zero.
Many uncertainties appear within the risk assessment concerning the
various exposure estimates. However, the risks of concern listed above
are of concern not only because the individual calculated risks are high
XTX
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and/or they may affect considerable numbers of individuals, but also
because they are based on sufficient empirical data and established
modeling techniques. The identified risks of possible concern have more
data gaps and are therefore of lesser certainty. The exposure modeling
for consumer products other than food/paper contact items estimated
levels of exposure yielding low individual risks. These exposure
estimates also contain various uncertainties; it is not felt, however,
that the degree of uncertainty is great enough to convert these low risks
to high risks.
Most noteable of the areas where there are data gaps is the nearly
total lack of actual sampling data on stack emissions of CDDs/CDFs from
the incineration of pulp and paper mill sludge. Only one actual measured
stack gas level of CDDs/CDFs was available for use in the incineration
exposure estimate. Although estimated airborne emissions and risks
appear low (using modeling and the very limited stack monitoring data),
incineration may become a more frequently used method of pulp and paper
sludge disposal.
There is also a lack of monitoring data on employee exposure to
CDDs/CDFs under actual working conditions. The occupational exposure
assessment estimates were made using surrogate data from a study of
particulate exposures, but with no actual CDD/CDF exposure data.
Similarly, only very limited site-specific data on industrial sludge land
disposal practices, locations, and associated exposed populations are
available to identify actual risks from land application of pulp and
paper sludge. Many of the individual risks calculated from modeled
exposures were quite high; without site-specific data, however, these
exposure scenarios remain hypothetical.
Data on marketing and consumer use of many of the new paper-packaged
and microwaveable food items is also very limited. In addition,
available information is not adequate to enable an assessment of risks to
infants who do not consume packaged foods at all, but rather consume
CDD/CDF-contaminated mother's milk. (Studies indicate infants are 10
times more sensitive than adults to deleterious effects of CDD/CDF;
further, studies of monkeys indicate that breast milk accumulates about
three times the CDD/CDF concentrations of fat tissue (Bowman et al.
1989).)
This assessment was begun as a specific response by the Agency to its
discovery that chlorine bleaching of wood pulp can result in dioxin
contamination of pulp and paper, wastewater effluent, and wastewater
treatment sludges. The narrow focus is not meant to imply that the
bleached pulp and paper industry is the only or even the major source of
CDDs/CDFs in the U.S. Other known sources of CDDs/CDFs include chemical
synthesis of chlorophenol products and derivatives, and stationary
combustion sources such as municipal waste combustors, electrical
equipment fires, and automobiles.
xx
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The risk assessment is also not a complete assessment of the health
risks due to chemical contamination from the bleached pulp and paper
industry. Chlorination of wood pulp produces numerous toxic compounds.
Although the only requirement of the consent decree was to investigate
CDDs/CDFs, EPA is aware that many other chlorinated organic compounds
(OCOs) are produced during pulp bleaching and processing operations.
These include chlorinated phenolic compounds, chlorinated guaiacols,
chlorinated catechols, chloroform, and hundreds of others. Further,
these other chemicals can be released to the environment in large
quantities. For example, a search of the 1987 Toxic Release Inventory
(TRI) data base indicated that 68 of the facilities in the 104-Mill Study
reported environmental releases of chloroform. For some facilities, the
releases were considerable, especially releases to air (as high as
1,700,000 Ib/yr from just one site). Even though other compounds may be
present at relatively low concentrations in pulp and paper mill
effluents, sludges, and pulps, the cumulative effect of CDDs/CDFs and
OCOs on exposed populations could be significant. Screening-level
analyses of OCOs in pulp mill effluents have been performed, although
similar analyses for the industrial sludge and pulp mass streams have
not. EPA's current effluent information, along with its understanding of
the toxicological aspects of these compounds, is presently insufficient
to support risk assessments on human and wildlife exposures to OCOs.
Although this risk assessment does not address risks associated with
these other chlorinated organics, the Office of Water will be considering
many of them in its effluent limitations guidelines and standards
revision.
xxi
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xxn
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1. INTRODUCTION
1.1 Purpose
The purpose of this report is to present the key findings,
assumptions, and uncertainties of an assessment of risks from exposure of
humans, terrestrial and avian wildlife, and aquatic life to dioxins and
furans formed during chlorine bleaching at kraft and sulfite pulp and
paper mills. This report contains condensed versions of eight major
exposure/risk'assessments and other support documents prepared by program
offices within the U.S. Environmental Protection Agency (EPA), the U.S.
Food and Drug Administration (FDA), and the U.S. Consumer Product Safety
Commission (CPSC). Risks were evaluated from roughly 120 potential
pathways of exposure to pulp and paper products, pulp and paper mill
sludges, and pulp and paper mill effluents. The development of this
assessment and the individual Agency exposure/risk assessments was
coordinated by the Federal Interagency Working Group on Dioxin-in-Paper.
The Background Document to this Integrated Assessment contains detailed
summaries of the individual exposure/risk assessments.
1.2 Background
1.2.1 Nature of the Problem _
The term "dioxin" commonly refers to a family of 210 structurally
related chlorinated aromatic compounds known as chlorinated dibenzo-p-
dioxins (CDDs) and chlorinated dibenzofurans (CDFs). The most toxic
member of this family is 2,3,7,8-tetrachlorodibenzo-p-dioxin
(2,3,7,8-TCDD). During the past 20 years, many studies have been
performed to determine the toxic effects of 2,3,7,8-TCDD. While data
generated from these studies have not answered all questions regarding
the toxicity of 2,3,7,8-TCDD, the data do show that 2,3,7,8-TCDD can
produce a variety of toxic effects, including cancer and reproductive
effects in laboratory animals at very low doses (USEPA 1989a). While
some reports in the literature suggest that the chemical can produce
similar effects in humans, more definitive information should be
forthcoming from epidemiological studies currently in progress (USEPA
1989a).
Based on the results of animal studies, EPA has classified
2,3,7,8-TCDD as a "B2" (or probable) human carcinogen with a plausible
upper bound slope factor, q^, of 1.6 x 10"4 (pg/kg-d)"1, by
far the most potent carcinogen evaluated to date by the Agency (USEPA
1989a). This chemical is also the most potent reproductive toxin yet
evaluated by EPA (USEPA 1989a). The closely related compound
2,3,7,8-tetrachlorodibenzofuran (2,3,7,8-TCDF) is assumed by EPA (through
use of the dioxin Toxicity Equivalency Factor (TEF) method adopted by the
Agency in 1987) to be one-tenth as potent as 2,3,7,8-TCDD.
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Recent studies (USEPA 1988, 1989b) have confirmed earlier reports
that both of these compounds can be formed when chlorine is used as a
bleaching agent for brightening and purifying wood pulp. These studies
indicate that the 2,3,7,8-TCDD and 2,3,7,8-TCDF formed can contaminate
the wastewater discharged from bleached kraft and sulfite pulp and paper
mills, the wastewater sludge generated at these mills, and the pulp and
paper products produced at these mills.
1.2.2 Discovery of the Problem
Theories about the formation of 2,3,7,8-TCDD and its presence in
various media have generated many studies. One landmark study was EPA's
National Dioxin Study, begun in 1983 and published in August 1987. This
was a nationwide, multimedia evaluation initiated at the request of
Congress in House Report 98-223. The study was requested in response to
growing public concern over the high toxicity and persistence of
2,3,7,8-TCDD and the numerous incidents of dioxin contamination and
exposure in the United States and abroad.
Results of the National Dioxin Study (USEPA 1987) indicated the
presence of 2,3,7,8-TCDD in fish and river sediment samples collected
downstream from some bleached kraft pulp and paper mills located in the
United States. In addition, 2,3,7,8-TCDD and other polychlorinated
dibenzodioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) were
detected in wastewater sludges from bleached kraft pulp and paper mills.
These findings prompted the EPA, the American Paper Institute (API), and
the Natio.nal Council of the Paper Industry for Air and Stream Improvement
(NCASI) to enter into an agreement, dated June 20, 1986, to jointly
perform the "USEPA/Paper Industry Cooperative Dioxin Screening Study"
(USEPA 1988) at five bleached kraft pulp and paper mills. The results of
this cooperative study, commonly referred to as the "5-Mill Study,"
indicated that dioxins were present in the treated effluent at three of
the five mills, in wastewater treatment sludges of all five mills, and in
bleached pulps at four of the mills. The principal PCDDs and PCDFs found
at the mills were 2,3,7,8,-TCDD and 2,3,7,8-TCDF. Results of the 5-Mill
Study indicated that 2,3,7,8-TCDD and 2,3,7,8-TCDF were formed during the
bleaching of kraft pulps with chlorine and chlorine derivatives.
Another study, performed by Arthur D. Little, Inc. (ADL 1987) under
contract to the EPA Office of Water (OW), was initiated to determine
whether CDD contamination of paper products had the potential for
significant risk to consumers. This scoping study (made available as a
draft report in 1987), though based almost entirely upon hypothetical
assumptions, demonstrated the possibility that risks from CDD-contaminated
food- and body-contact papers could be of concern.
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1.2.3 Federal Response
To coordinate the federal government's response to the findings of
the three studies, an interagency workgroup was formed in 1987 among the
Food and Drug Administration (FDA), the Consumer Product Safety
Commission (CPSC), and various program offices within EPA including the
Office of Toxic Substances (OTS), the Office of Solid Waste (OSW), the
Office of Research and Development (ORD), the Office of Air Quality
Planning and Standards (OAQPS), and the Office of Water (OW). The
National Institute of Occupational Safety and Health (NIOSH) joined later.
The mission of the interagency workgroup was to conduct a coordinated
assessment of the problem of CDDs/CDFs in bleached wood pulp, and, as
appropriate, to provide the vehicle for a coordinated agency response.
Analytical responsibilities were divided among the agencies/offices and
were split into three broad "tiers." Tier one is the determination of
CDD/CDF levels in pulp, effluent, and industrial sludge for bleached
kraft and sulfite pulp and paper mills in the United States. Tier two is
the risk assessment for paper product contamination, effluent discharge,
and sludge disposal. Tier three is the examination of technological
options for reducing CDD/CDF formation, and release from bleached chemical
pulp and paper facilities.
Tier one, the EPA/Paper Industry Cooperative Dioxin"Study of 104 pulp
and paper mills, began in April 1988 when EPA, API, NCASI, and 44 paper
companies signed an agreement outlining the data to be collected and
submitted to EPA for use by the Interagency Working Group. This study,
commonly referred to as the "104-Mill Study" involved measurement of
2,3,7,8-TCDD and 2,3,7,8-TCDF concentrations in the treated wastewater
effluents, wastewater sludges, and all bleached pulp lines at 87 kraft
pulp mills and 17 sulfite pulp mills in the United States. Data on
wastewater treatment operations, wastewater discharge characteristics,
and sludge management practices were also collected during the course of
this study. Results of the 104-Mill Study indicated that concentrations
of 2,3,7,8-TCDD in kraft pulp were considerably higher than concentrations
of 2,3,7,8-TCDD in sulfite pulp. In addition, concentrations of
2,3,7,8-TCDF measured during the 104-Mill Study were roughly an order of
magnitude greater than those of 2,3,7,8-TCDD. Furthermore, results of
the 104-Mill Study indicated that the presence of 2,3,7,8-TCDD and
2,3,7,8-TCDF in treated effluent, wastewater sludges, and bleached pulps
from pulp and paper mills using chlorine-based bleaching processes was
widespread. Table 1 provides a general summary of the results of the
104-Mill Study.
The tier two exposure analysis and risk characterization has been
divided among the various agencies/offices who have jurisdiction over the
media of concern. OTS was assigned the lead on this tier for coordinating
and generating an integrated exposure and risk assessment.
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8941H
Table 1. Smmary Results of the 104 Mill Study9
Pulp
2.3.7.8-TCDD
2.3.7.8-TCOF
Effluent
2.3.7.8-TCDD
2.3.7.8-TCDF
Sludge
2.3.7.8-TCDD
2.3.7.8-TCDF
Rangeb
(ng/kg)
ND-116
ND-2.620
ND-0.640
ND-8.400
HD-3,800
2.4-17.100
Mean
(ng/kg)
8.8
94.9
0.068
1.033
77.5
749.6
Median
(ng/kg)
4.9
19.0
0.023
0.094
18.0
89.0
No. of mills
Std. Dev. with no detected
(ng/kg) values
11.8 21
283.7 6
0.106 20
2.358 7
163.9 2
2.079 0
a Based on final results obtained from EPA's Office of Water Regulations
and Standards in October 1989.
The analytical objectives for detection limits of both confounds Mere
0.01 ng/kg (or ppt) for effluents and 1 ppt for pulps and sludges.
-------
Tier three of the analytical responsibilities is a review of current
technologies for CDD/CDF control and abatement in the three mass
streams. OW, the lead office, is assessing the effectiveness of numerous
control technologies for reducing CDD/CDF formation in the pulp and paper
industry. OW is now preparing a technology review document, which will
draw on information from National Pollutant Discharge Elimination System
(NPDES) permits being negotiated with pulp and paper mills around the
country, as well as from the continuing efforts under the effluent
limitations guidelines and standards revision project and the 104-Mill
Study. The document will not be finalized until after the industry
census and mill sampling programs are complete.
1.2.4 Consent Decree
On October 22, 1984, the Environmental Defense Fund (EOF) and the
National Wildlife Federation (NWF) filed a citizen's petition with EPA
under Section 21 of the Toxic Sustances Control Act (TSCA). The
petitioners requested that EPA take regulatory action under Sections 4,
6, and 8 of TSCA to prevent and reduce environmental contamination by
CDDs and CDFs. EPA decided in January 1985 that in general it would deny
-the request to regulate the specified CDDs/CDFs under a multimedia TSCA
approach.
In March 1985, the petitioners filed a lawsuit with the U.S. District
Court challenging EPA's denial of their request. Before the case was to
go to trial, a settlement was reached and a consent decree (Civil Action
No. 85-0973) was signed on July 27, 1988, settling the dispute. The
consent decree obligated EPA to undertake or complete various actions/
investigations of CDDs/CDFs, including the CDD/CDF work related to the
pulp and paper industry.
The consent decree set a schedule for assessing both occupational and
general population health risks and environmental risks to terrestrial
and avian wildlife and aquatic life from CDD/CDF-contaminated pulp and
paper mill wastewater, wastewater sludge, and paper products. Although
the interagency workgroup was formed before the consent decree with
EDF/NWF, the workgroup has served as the mechanism for coordinating
federal government efforts to meet the consent decree requirements.
1.3 Scope and Organization of the Integrated Risk Assessment
The Integrated Assessment includes the following components in the
order listed:
An analysis of the chemistry and environmental fate of
2,3,7,8-TCDD and 2,3,7,8-TCDF;
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An assessment of the hazard/toxicity of 2,3,7,8-TCDD and
2,3,7,8-TCDF to humans, aquatic organisms, and avian and
terrestrial wildlife;
An assessment of exposures and risks to workers in the pulp and
paper industry;
Assessments of exposures and risks to the general population
from:
- Use and disposal of pulp and paper mill wastewater sludge and
land disposal of paper waste,
- Discharge of effluents from the pulp and paper industry,
- Incineration of pulp and paper mill wastewater sludge,
- Use of pulp-containing medical devices,
- Use of paper consumer products,
- Ingestion of foods packaged in or contacting bleached paper
products, and
- Use of food, drug, and cosmetic products containing cellulose
derivatives;
An assessment of exposures and risks to avian and terrestrial
wildlife from land application of sludge and to aquatic organisms
from the discharge of pulp and paper mill effluents; and
A screening analysis of information on chlorinated chemicals
other than PCDDs and PCDFs (OCOs) identified in pulp and paper
mill effluents, sludges, and pulps.
Summaries of the individual chapters of the Background Document to the
Integrated Risk Assessment are presented in the same sequence .in_this
Integrated Assessment as they appear in the Background Document. For
each chapter of the Background Document, Section 2 of this Integrated
Assessment provides the following:
A discussion of the exposure pathways considered;
A description of the general methodology employed; and
A presentation of the key findings or results and a discussion
of the key findings, major assumptions, and associated
uncertainties.
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2. INTEGRATED RISK ASSESSMENT
2.1 Common Assumptions
This section provides a summary of the methodologies used, major
assumptions, results and key findings, and uncertainties associated with
each exposure/risk assessment performed as part of the Integrated Risk
Assessment for the Dioxin-in-Paper Project. This section is organized to
reflect the organization of the Background Document to the Integrated
Assessment.
Although many scenarios using different methodologies were assessed
by the various agencies and offices participating in the Dioxin-in-Paper
Project, several common assumptions were agreed to by the participants.
(1) The Toxicity Equivalency Factor (TEF) method states that
2,3,7,8-TCDF is assumed to have one-tenth the potency of
2,3,7,8-TCDD. EPA and FDA agreed to employ this policy for this
assessment. Because CPSC does not place similar emphasis on
risks calculated by the TEF method, it was agreed that, to the
extent possible, CPSC risk estimates for each scenario would be
based on the contribution to risk of 2,3,7,8-TCDD alone.
(2) The assessments focused on exposures and risks to 2,3,7,8-TCDD
and 2,3,7,8-TCDF. Based on the TEF values formally adopted by
EPA in 1987, the results of the 5-Mill Study indicated and the
results of the 104-Mill Study confirmed that these two dioxin
congeners generally account for more than 90 percent of the
dioxin toxic equivalents (TEQ) found in pulps, sludges, and
effluents from the pulp and paper mill samples analyzed.
(3) EPA, FDA, and CPSC have each derived an estimated slope factor
(qj* or qj) for 2,3,7,8-TCDD based on a multistage model with
linear-at-low-dose extrapolation procedures. However, because
the agencies differ with respect to selection of animal data and
details of extrapolation, the risk estimates differ by as much
as a factor of 10. The agencies agreed that this Integrated
Assessment would report cancer risk estimates calculated by each
agency.
(4) The analytical results of the 104-Mill Study (i.e., 2,3,7,8-TCDD
and 2,3,7,8-TCDF concentrations in pulp, effluents, and sludge)
were to be used in all assessments unless use of alternate data
(e.g., product-specific concentrations) could be justified.
(5) With the exception of risks calculated by EPA/OSW and EPA/OW,
all estimated human cancer risks were calculated by multiplying
the estimated lifetime average daily doses (LADD) by the slope
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factor (q,* or q.) for 2,3,7,8-TCDD and dividing by the fraction
of TCDD absorbed (A) during the animal bioassay from which the
slope factor was derived:
Risk = (LADD x qJ/A
The value of A depends on the fraction of 2,3,7,8-TCDD absorbed
by the test animals during the bioassay used to estimate q,
or qt*. For the EPA and FDA slope factors, which are based
on a dietary bioassay, A is assumed to equal 0.55 since it was
estimated that 55 percent of the 2,3,7,8-TCDD was absorbed by the
test animals; similarly, for the CPSC slope factor, which is
based on a gavage bioassay, A is assumed to equal 0.75. The
total or population risk was estimated by multiplying the
average lifetime risk by the number of persons exposed and
dividing by the average life expectancy.
(6) With the exception of the bioavailability values used by EPA/OSW
for each ingestion pathway applicable to sludge disposal and
use, standard values developed for the bioavailability, or
fraction of 2,3,7,8-TCDD and 2,3,7,8-TCDF absorbed, were
developed and used for each exposure route and pathway. For the
inhalation exposure route, the bioavailability was assumed to be
100 percent for 2,3,7,8-TCDD and 2,3,7,8-TCDF vapors and 100
percent for particulate-bound 2,3,7,8-TCDD and 2,3,7,8-TCDF that
reach the alveoli. Standard values for the bioavailability of
.2,3,7,8-TCDD and 2,3,7,8-TCDF were assumed to be 100 percent for
ingestion of drinking water, 85 to 95 percent for ingestion of
fatty or oily foods (e.g., milk, fish, meats), 60 to 70 percent
for ingestion of paper dust and sludge, and 45 to 55 percent for
ingestion of soil. EPA/OSW, however, assumed 100 percent
absorption for each exposure pathway applicable to sludge
disposal and use except for dermal exposures. For dermal
exposures, a dermal transfer coefficient of 0.012/hour is
assumed for 2,3,7,8-TCDD and 2,3,7,8-TCDF that are not bound up
within a matrix (e.g., soil or paper products).
A variety of terms were used in the source documents for the
Integrated Assessment to describe the exposure case or exposed individual
for which risks were estimated. Many of these terms are presented in the
Background Document to the Integrated Risk Assessment and in Section 2 of
this report as they appear in the source document. These exposure case
descriptions include low, high, average, typical, reasonable worst case,
extreme worst case, and maximum exposed individual (MEI). Such exposure
case descriptions are used by exposure/risk assessors to describe where
in the range of exposures possible for a given scenario they either know
(from a statistical array of exposures or exposure parameter values) or
8
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judge the calculated exposure to reside. Historically, there has been no
generally accepted convention or guidance specifying what defines a given
exposure description. Therefore, the use of these terms is not consistent
within this report.
To provide some consistency in summarizing the results of the
Integrated Assessment source documents, the various exposure case
descriptions used in the source documents have been reduced in this
section into the following two classifications: typical and reasonable
worst-case. The majority of exposure cases developed in the source
documents fit into one of these two categories if the following somewhat
broad definitions are used:
Typical exposure - exposure parameter values selected are (1) values
conventionally used for certain exposure parameters; (2) average or
most probable values when distribution data for the parameter are
available; or (3) values considered "typical" or frequently observed
based on best professional judgment.
Examples of the types of exposures mentioned in this report that
would be characterized as typical include inhalation of volatilized
2,3,7,8-TCDD/TCDF; inhalation of particulate matter (i.e., paper dust
or sludge) containing 2,3,7,8-TCDD/TCDF; dermal contact with pulp,
paper, or sludge containing 2,3,7,8-TCDD/TCDF;"and ingestion of food,
water, and drugs containing 2,3,7,8-TCDD/TCDF.
Reasonable worst-case exposure - similar to typical exposure with the
exception that values for one or more significant exposure parameters
are selected within the upper portion of the range of actual or
expected values so that the resulting exposure calculated represents
a relatively high but possible exposure.
Examples of the types of exposures mentioned in this report that
would be characterized as reasonable worst-case include those cases
in which an individual is exposed to the highest possible
concentration (i.e., 90th percentile and above) or instances where an
individual is exposed at a frequency or duration higher than what is
typically observed.
2.2 Summary of the Chemistry and Fate of 2.3.7.8-TCDD and
2.3.7.8-TCDF
l
The primary source document used for this chapter in the Background
Document is the following:
Versar, Inc. 1989. Chemistry and fate of dioxins and furans. U.S.
Environmental Protection Agency (EPA), Exposure Evaluation Division,
Office of Toxic Substances. Contract No. 68-02-4254, Task 231.
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2.2.1 Chemistry and Fate of 2,3,7,8-TCDD
2,3,7,8-Tetrachlorodibenzo-prdioxin (2,3,7,8-TCDD) is one of the 75
compounds known as chlorinated dibenzo-p-dioxins (CDDs). The structure
of 2,3,7,8-TCDD is:
2,3,7,8-TCDD is very sparingly soluble in water (20 ng/1 at 22°C),
has a high octanol-water partition coefficient (log P = 6.64), shows
strong sorption to organic matter (log KQg = 7.2), and has a low vapor
pressure (7.4 x 10"10 torr at 25°C) but will volatilize into
the air under favorable conditions.
2,3,7,8-TCDD is persistent in soils. Upon deposition of 2,3,7,8-TCDD
onto surfaces, there is a high initial loss due to photodegradation and
perhaps volatilization. Once 2,3,7,8-TCDD moves into soils or sediments,
however, it is ^apparently strongly sorbed. Some recent studies, however,
have shown that there may be slow rates of vapor phase transport out of
soils, although other recent studies have shown very low mobility.
The only environmentally significant path for destruction of
2,3,7,8-TCDD appears to be photodechlorination. This process, however,
requires the presence of another organic material to donate hydrogen
atoms. Observations of bioaccumulation indicate that 2,3,7,8-TCDD is
readily bioconcentrated in fish, but the data for humans are
inconclusive. Dioxins in soil and sediments are considered to be
essentially nonbiodegradable. Erosion and aquatic transport of sediment
appear to be the main transport mechanism of sorbed dioxins. Table 2 is
a summary of the environmental fate of 2,3,7,8-TCDD.
2.2.2 Chemistry and Fate of 2,3,7,8-TCDF
2,3,7,8-Tetrachlorodibenzofuran (2,3,7,8-TCDF) is one of the 135
compounds characterized as chlorinated dibenzofurans (CDFs). The
structure of 2,3,7,8-TCDF is:
2,3,7,8-TCDF has a low solubility in water (estimated solubility of
4.3 /ig/1 at 25CC), has a high octanol-water partition coefficient
.(log P = 5.8)* .and has a low vapor pressure (9.2 x 10'7 torr at
25'C).
10
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8941H
Table 2. Suanary of Environmental Fate of 2,3.7.8-TCDD
Environmental
process
Summary
statement
Confidence
in data
Photolysis
Oxidation
Hydrolysis
Volatilization
Sorption
Bioaccuaulation
Biodegradation
Nay be only natural Mechanism
leading to destruction of
dioxins.
Oioxins are stable to oxidation.
Dioxins are stable to
hydrolysis.
Possible important mechanism
for transport fron water.
Volatility depressed by
presence of organic solids.
Oioxins strongly sorbed by
solids, especially with high
organic content.
Available data indicate process
may be important. The data
show high degree of confidence
for bioconcentration in fish,
but low confidence in the limited
data concerning bioaccumulation
in humans.
Considered essentially non-
biodegradable.
High
Low
High
Medium
High
Medium
Medium
11
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Polychlorinated dibenzofurans can be photodechlorinated by sunlight
in the presence of organic substances that can serve as donors of
hydrogen atoms. This process of photodechlorination is similar to what
occurs in the degradation of dioxins, and it is probably the only
degradative fate pathway for dibenzofurans in the environment.
Since there is little or no information on dibenzofurans for other
environmentally relevant processes, fate and transport pathways must be
derived from the behavior of structurally similar dioxins. 2,3,7,8-TCDF
can be expected to be sorbed strongly to soils and sediments, to be
bioconcentrated in fish, and to be essentially nonbiodegradable in the
environment. Erosion and aquatic transport of sediment will be the main
transport pathway. Table 3 is a summary of the environmental fate of
2,3,7,8-TCDF.
2.3 Summary of Hazard Assessment for TCDD/TCDF
The hazard assessment considered carcinogenic and noncarcinogenic
effects on humans, toxicity to aquatic organisms, and toxicity to avian
and terrestrial wildlife. The primary source documents used for this
chapter in the Background Document are the following:
Human health section:
Lee CC. 1989. Human health hazard assessment of dioxins/furans.
U.S. Environmental Protection Agency, Office of Toxic Substances.
Memorandum to L. Dicker, EPA, Office of Toxic Substances, October 31,
1989.
Ecological effects section:
Rabert WS. 1989. Update of aquatic toxicity and bioavailability
data of polychlorinated dibenzo-p-dioxins and polychlorinated
dibenzofurans. U.S. Environmental Protection Agency, Office of Toxic
Substances. Memorandum to S. Kroner, EPA, Office of Water
Regulations and Standards, July 28, 1989.
Wildlife effects section:
USEPA. 1990. U.S. Environmental Protection Agency. Assessment of
risks from exposure of humans, terrestrial and avian wildlife, and
aquatic life to dioxins and furans from disposal and use of sludge
from bleached kraft and sulfite pulp and paper mills. Washington,
DC: Office of Toxic Substances and Office of Solid Waste. EPA
560/5-90-013.
2.3.1 Human Hazard Assessment
Among the 210 congeners of CDDs and CDFs, the compound that appears
to be the most toxic and has generally raised the greatest health
12
1578q
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8941H
Table 3. Summary of Environmental Fate of Dibenzofurans
Environmental
process
Sunnary
statement
Confidence
in data
Photolysis
Oxidation
Hydrolysis
Volatilization
Sorption
Bioaccunulation
Biodegradation
Hay be only natural mechanism
leading to destruction of
dibenzofurans.
No information found.
Dibenzofurans are stable to
hydrolysis.
No information found.
Dibenzofurans strongly sorbed by
solids, especially with high
organic content.
No specific information found;
potential is inconclusive.
Probably nondegradable in the
environment.
Medium
Low
High
Low
Medium
Low
Low
13
-------
concerns is 2,3,7,8-TCDD. 2,3,7,8-TCDD is classified by the EPA as a
probable human carcinogen based on sufficient evidence in animals but
inadequate evidence in humans. The EPA cancer risk estimate is
represented as the upper bound slope factor, q,*. The CPSC cancer
risk estimate is represented as the maximum likelihood estimate of the
extra risk, qj. The FDA approach is an upper bound estimate of the
unit risk or potency by means of the linear-at-low-dose extrapolation.
The cancer risk estimates derived for 2,3,7,8-TCDD by EPA, FDA, and CPSC
differ by as much as a factor of 10, with a value of 1.6 x 10"4
(pgAg/day)'1 estimated by EPA, a value of 6.7 x 10'5 (pg/kg/day)'1
estimated by CPSC, and a value of 1.8 x 10'5 (pg/kg/day)"1 estimated by
FDA. The estimated exposures giving an upper bound excess lifetime
cancer risk of one in one million based on the upper bound slope factor
or maximum likelihood of extra risk are 0.006 pg/kg/day (EPA),
0.015 pg/kg/day (CPSC), and 0.06 pg/kg/day (FDA). Although all three
agencies based their estimates on linear-at-low-dose extrapolation
procedures, they differ with respect to selection of animal data and
details of extrapolation.
In the spring of 1987, EPA formally adopted an interim procedure for
estimating risks associated with exposures to mixtures of the 210
congeners of CDDs and CDFs, including 2,3,7,8-TCDD. This interim
procedure was updated in 1989. The procedure uses a set of derived
toxicity equivalency factors (TEFs) to convert the concentration of any
CDD/CDF congener into an equivalent concentration of 2,3,7,8-TCDD. In
this procedure, 2,3,7,8-TCDD is assigned a TEF of 1. The TEF for
2,3,7,8-TCDF is one-tenth that for 2,3,7,8-TCDD. It must be noted that,
although FDA concurs with EPA on the use of TEFs, CPSC does not. Because
of the limited carcinogenicity studies for individual dioxin congeners,
CPSC prefers to estimate cancer risks using a method based on
2,3,7,8-TCDD alone rather than using the method based on TEFs.
In assessing the risk of non-cancer effects, adverse effects
resulting from long-term, low-level exposure and from relatively brief
exposure to a high dose must be considered. The Reference Dose (RfD) is
used to evaluate long-term oral exposures to a chemical. The RfD is an
estimate of the lifetime daily exposure to which humans can be exposed
without any appreciable risk of experiencing deleterious effects. The
Health Advisory (HA) is used to evaluate brief exposures to high doses of
a chemical. EPA determined that reproductive effects and developmental
toxicity in animals are the most critical or sensitive noncarcinogenic
effects to consider for assessing risks from exposure to 2,3,7,8-TCDD.
For purposes of this assessment, EPA estimated an RfD for 2,3,7,8-TCDD of
1 pg/kg/day based on studies conducted to assess the possible adverse
effects of chronic oral 2,3,7,8-TCDD exposure on reproductive capacity.
For purposes of this assessment, EPA estimated a 1-day HA of 300 pg/kg/day
and a 10-day HA of 30 pg/kg/day based on studies conducted to assess the
potential developmental toxicity of short-term exposure to 2,3,7,8-TCDD
14
1578q
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during pregnancy. For purposes of this assessment, EPA estimated a 1-day
HA of 100 pg/kg/day and a 10-day HA of 10 pg/kg/day based on studies
conducted to assess potential systemic effects (liver pathology).
2.3.2 Aquatic Organism Hazard Assessment
To assess the toxicity of chemicals to aquatic species, the highest
concentration at which no adverse effect is observed (NOEC) should be
determined. A definitive NOEC has not been reported for 2,3,7,8-TCDD.
Even the lowest test concentration among all known 2,3,7,8-TCDD studies
(0.038 ng/1) produced 45 percent mortality in rainbow trout exposed to
2,3,7,8-TCDD for 28 days. Data from testing laboratories suggest that an
exposure duration of greater than 71 days is required to achieve a
steady-state bioconcentration factor (BCF) in fish.* The NOEC reported
for 2,3,7,8-TCDF is 0.41 ng/1. This value for NOEC is also uncertain
because of the limited duration of the study. The toxicity data
available on 2,3,7,8-TCDD and 2,3,7,8-TCDF do not adequately define the
inherent toxicity of these two chemicals for two reasons: (1) the
exposure periods are of insufficient duration for a steady-state
equilibrium to be reached, and (2) the studies do not address sublethal
effects for the most sensitive life stages, such as effects on developing
embryos resulting from deposition of either 2,3,7,8-TCDD or 2,3,7,8-TCDF
in the eggs by the female.
Since definitive chronic toxicity values are not available for
2,3,7,8-TCDD and 2,3,7,8-TCDF effects on aquatic species, especially
fish, chronic toxicity values were estimated from the results of the
tests discussed above through use of an estimation factor of 1,000. The
Office of Water uses values of this magnitude for certain chemicals when
chronic toxicity data are not available. In addition, OTS uses a factor
of 1,000 to predict the chronic toxicity of a substance from a single
LCc0 value in the Premanufacture Notice process of Section 5 under
TSCA. The OTS factor of 1,000 does not include any safety factor;
rather, the factor of 1,000 consists of a series of intervals with
average factors of 10. Included in the three factors of 10 are (1) a
range of differences in species sensitivity; (2) an acute to chronic
toxicity (i.e., LC50 to the maximum acceptable toxicant concentration
(MATC) value); and (3) the differences in field-to-laboratory toxic
effects. Given the fact that the LCc0 value for 2,3,7,8-TCDD could
be lower than 38 pg/1 for fish, a 1,000 factor was deemed to be
appropriate for purposes of this study as an estimate for chronic
toxicity. This factor is justified for use in this study because the
exposure duration was too short to achieve a steady-state condition and
the tests did not involve developing eggs, which are, to date, the life
stage found to be the most sensitive. Consequently, it was assumed for
the purpose of this assessment that concentrations of 2,3,7,8-TCDD in
water greater than 0.038 pg/1 will exhibit toxic effects to some aquatic
*Personal communication between William Rabert, EPA/OTS Washington, DC,
and:Phil Cook, EPA/ERL, Duluth, MN.
15
1578q
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species. Applying the same approach to 2,3,7,8-TCDF, it was assumed that
concentrations of 2,3,7,8-TCDF greater than 0.41 pg/1 will exhibit toxic
effects for some aquatic species:
2.3.3 Wildlife Hazard Assessment
The adverse effects to individual laboratory and wildlife species
from exposure to 2,3,7,8-TCDD have been documented in laboratory
studies. Extrapolation of these results to wild populations has some
limitations. The route and medium of administration and the duration of
exposure to 2,3,7,8-TCDD for laboratory animals usually differ from those
for wild animals. Using laboratory studies to assess effects on wild
species assumes that the wild species are as sensitive or more sensitive
to 2,3,7,8-TCDD than the laboratory species. Many of the tests conducted
with terrestrial laboratory species identified toxic effects at elevated
exposure levels for a short observation period. However, it was noted in
tests with aquatic organisms that more than 71 days of exposure was
necessary for equilibrium and that toxic effects may not appear until 30
to 80 days after initiation of exposure. Furthermore, in assessing the
effects of chemicals on fish and wildlife, the impacts on a population or
ecosystem are of interest. The methods for predicting the effects of
chemicals on terrestrial wildlife populations and ecosystems, however,
are still under development. In the absence of sophisticated predictive
methods, measures of the effects of chemicals on reproduction are useful
indicators of possible effects on the populations of the species of the
wild.
To assess toxic effects to birds, the estimated daily exposure to
adult wild birds was compared to a no observable adverse effects level
(the NOAEL) of 100 ng/kg/day reported in a 21-day exposure period
laboratory study with white leghorn chickens. This laboratory dose was
converted to an equivalent exposure over the length of time that wild
species of birds may be exposed to 2,3,7,8-TCDD from sludge applied to
agricultural or forested areas. Because migratory birds were assumed to
reside in the land-treated area for 6 months (180 days), the NOAEL was
adjusted by a "residence time/exposure period" factor of 180/21 (or about
9). Thus, the adjusted NOAEL for migratory birds is 11 ng/kg/day.
Non-migratory birds were assumed to remain onsite for the entire year.
Thus, for non-migratory species, the NOAEL is adjusted by a "residence
time/exposure period" factor of 365/21 (or about 17). The adjusted NOAEL
for non-migratory species is therefore 6 ng/kg/day.
The life stage in avian species most sensitive to 2,3,7,8-TCDD is the
developing embryo during resorption of the yolk. To assess toxic effects
on bird eggs, the predicted 2,3,7,8-TCDD concentration in wild bird eggs
was compared to the lowest observable adverse effects level (the LOAEL)
reported in a laboratory study with chicken embryos, 65 ppt; no NOAEL was
found.
16
1578q
-------
To assess toxicity to wild mammals, the predicted exposures were
compared to the lowest concentration observed to cause reproductive
effects in laboratory animals. For small mammals, a LOAEL of 10 ng/kg/day
was used based on the results of a multi-generational study with rats.
For large mammals, a LOAEL of 1.7 ng/kg/day was used based on a
reproductive effects study with Rhesus monkeys.
2.4 Summary of Risks to Workers
2.4.1 Introduction
This risk assessment is discussed in more detail in Chapter 4 of the
Background Document. The primary source documents used for this chapter
in the Background Document are the following:
PEL 1990a. PEI Associates, Inc. Estimated worker exposure to
2,3,7,8-TCDD and 2,3,7,8-TCDF in the manufacture, processing, and
commercial use of pulp, paper, and paper products. Washington, DC:
U.S. Environmental Protection Agency, Office of Toxic Substances.
Contract No. 68-D8-0112. March 1990.
PEI. 1990b. PEI Associates, Inc. Estimated worker exposure to
2,3,7,8-TCDD and 2,3,7,8-TCDF from processing and commercial use of
pulp and paper mill sludge. Washington, DC: U.S." Environmental
Protection Agency, Office of Toxic Substances. Contract No.
68-D8-0112. April 12, 1990.
This assessment examined risks to workers in the following industries:
Pulp manufacturing;
Paper manufacturing;
Paper converting;
Nonwoven fabric production;
Commercial users of bleached paper (i.e., office workers,
salespersons, mail/message distributors, medical workers); and
Sludge processing and commercial use operations (i.e.,
handling/processing, landfilling, composting, land application,
etc.).
The assessment identified those job categories in each industry with the
potential for exposure via one or more of the following exposure pathways:
Inhalation of 2,3,7,8-TCDD and/or 2,3,7,8-TCDF vapors;
Inhalation of particulate matter (i.e., paper dust or sludge
particles); and/or
Dermal contact with pulp, paper, or sludge.
17
1578q
-------
2.4.2 Methodology
In assessing risks to workers, low and high individual risks and low
and high population risks were estimated using generic exposure
scenarios. The lowest and highest dioxin TEQ concentrations reported in
the 104-Mill Study for the matrix of concern were used to estimate the
"low" and "high" estimates of risk, respectively. For example, risk
estimates for workers involved in composting operations are based on the
lowest and highest dioxin TEQ concentrations in sludge from those mills
that report using composting as a sludge disposal reuse method.
Exposure via volatilization pathways was estimated using models that
were based on either a mass balance approach for specific activities
(e.g., for pulp testers during sampling) or an approach that estimated
maximum air concentrations based on the partial pressures of 2,3,7,8-TCDD
and 2,3,7,8-TCDF. Estimates of exposure via inhalation of particulate
matter during paper converting and nonwoven operations were based on
monitored air concentrations of particulates. For all other paper
manufacturing and processing operations, data from NCASI on particle size
distribution of paper dust were used to estimate concentrations of
particulates in air. For operations involving processing and commercial
use of sludge, particulate matter emission rates were estimated based on
EPA's widely used AP-42 Compilation of Air Pollution Emission Factors.
Measured concentrations of 2,3,7,8-TCDD and 2,3,7,8-TCDF in paper were
not available; it was, therefore, assumed that concentrations of
2,3,7,8-TCDD and 2,3,7,8-TCDF in paper were the same as the concentrations
of these chemicals in pulp. In addition, the concentrations of
2,3,7,8-TCDD and 2,3,7,8-TCDF in the particulates from sludge or paper
were assumed to be the same as in the source material (i.e., sludge or
paper). Dermal exposures were estimated using a two-step model that
first considers partitioning of the 2,3,7,8-TCDD/TCDF from the matrix
(i.e., sludge, pulp, etc.) to a liquid (water, skin oil) and then
considers percutaneous absorption of 2,3,7,8-TCDD/TCDF from the liquid.
2.4.3 Results and Discussion
Table 4 presents estimates of risk by exposure pathway for.,ea.ch job
category for workers involved in manufacturing, processing, and
commercial use of pulp, paper, and paper products. Table 5 presents
similar results for workers involved in processing and commercial use of
pulp and paper mill sludge.
As evident in Tables 4 and 5, only "high" individual risks were
estimated to be greater than 10"5. Estimates of "high" individual risk
represent those plants in which the medium to which the worker is exposed
contains the maximum dioxin TEQ concentrations. Risks greater than
10~5 result from inhalation of particulate matter and dermal contact.
It should be noted that the extent of use and effectiveness of personal
18
1578q
-------
8941H-5
Table 4. Suirmary of Individual and Population Cancer Risks for Workers Involved in Manufacturing,
Processing, and Commercial Usage of Pulp, Paper, and Paper Products
No. of
Job category workers Exposure pathway
Pulp manufacturing operations
- Bleach plant operator 434 Inhalation-volatilization
Dermal
- Pulp testers 433 Inhalation-volatilization
Dermal
- Utility operator 433 Inhalation-volatilization
Dermal
Pulp drying operations
- Pulp drying operator 160 Inhalation-volatilization
Dermal
- Pulp drying utility operator 80 Inhalation-volatilization
Dermal
Paper manufacturing operations
- Wet-end operator 10,667 Inhalation-volatilization
Dermal
a
Estimated risk
Population risk
Individual risk (I cases/vr)
Low
4xlO"7
(0.08)
2xlO"13
(47)
IxlO"19
(0.03)
2xlO"12
(47)
IxlO"6
(0.08)
4xlO"12
(47)
2xlO"H
(0.03)
9xlO"10
(29)
2xlO"H
(0.03)
2xlO"13
(29)
2xlO~n
(0.03)
2x10 1J
(47)
High Low
SxlO"7 4xlO"6
(0.08)
SxlO"10 3xlO"12
(4)
2xlO"15 IxlO"18
(0.002)
3xlO"9 2xlO~n
(4)
IxlO"6 IxlO"5
(0.08)
7xlO"9 4xlO"H
(4)
2xlO"7 7xlO"U
(0.002)
3xlO"6 4xlO"9
(2)
2xlO"7 SxlO"11
(0.002)
5xlO"10 SxlO"13
(2)
2xlO"7 SxlO"9
(0.002)
SxlO"10 7xlO~n
(4)
High
SxlO"6
6xlO"9
3x1 O"14
4x1 O"8
2xlO"5
7x1 O"8
9xlO"7
IxlO"5
4xlO"7
IxlO"9
6xlO"5
IxlO"7
19
-------
8941H-6
Table 4. (Continued)
a
Estimated risk
No. of Individual risk
Job category workers Exposure pathway Low
Paper manufacturing operations
(continued)
- Dry-end operator 12.445 Inhalation-volatilization 3x10
(0.03)
Inhalation-particulate matter 2x10
(29)
Dermal 2xlO"10
(29)
- Utility operator ' 8,888 Inhalation-volatilization SxlO"11
(0.03)
_Q
Inhalation-particulate matter 8x10
(29)
Dermal 3xlO"10
(29)
Paper converting operations
- General worker 129.000 Inhalation-particulate matter 4x10
(29)
Dermal 4xlO"10
(29)
Nonwoven operations
- General worker 15,000 Inhalation-particulate matter 4x10
(29)
Dermal 8xlO"13
(29)
High
4xlO"7
(0.002)
IxlO"5
(2)
7xlO"7
(2)
7xlO"7
(0.002)
8xlO"5
(2)
IxlO"6
(2)
5xlO"5
(2)
IxlO'6
(2)
3xlO"6
(2)
3xlO"9
(2)
Population risk
(# cases/vr)
Low High
IxlO"8 IxlO"4
6x1 O"8 5x1 O"3
6xlO"8 2xlO"4
IxlO"8 IxlO"4
2xlO"6 2xlO"2
6xlO"8 2xlO"4
IxlO"6 2xlO"J
IxlO"6 4xlO"3
IxlO"7 IxlO"3
3xlO"10 IxlO"6
20
-------
8941H-7
Table 4. (Continued)
Estimated risk
No. of
Job category workers Exposure pathway
Comnercial users
- Group 1 2,639,000 Dermal
- Group 2 26,933,000 Dermal
- Group 3 5,004,000 Dermal
- Group 4 14,095,000 Dermal
- Group 5 793,000 Dermal
-
Individual risk
Low
7xlO"n
(29)
5X10'11
(29)
2xlO"n
(29)
2xlO'n
(29)
SxlO'10
(29)
High
3xlO'7
(2)
2xlO'7
(2)
8x1 O"8
(2)
8xlO'8
(2)
BxlO'7
(2)
Population risk
(t cases/vrl
Low High
.
5xlO"6 2xlO~2
3xlO"6 IxiO"2
IxlO"6 5xlO"3
2xlO"6 6xlO"3
2x1 O"5 5xlO~2
a EPA has classified 2,3,7,8-TCDD as'a~"B2"~ carcinogens Values"iirparentheses'-Tepresent-percent~exposure to 2,3,7.8-TCOO.
Risks presented were calculated using the EPA unit risk estimate for 2,3,7,8-TCDD and the TEQ method. This unit risk
estimate was derived using the EPA carcinogenic slope factor for 2,3,7,8-TCDD (1.6x10 (pg/kg/d) ). Had risks been
calculated using FDA's potency estimate (1.8x10 (pg/kg/d) ), then the risks and incidences would be a factor of 6,9
lower than those presented in the table. Had risks been calculated using CPSC's potency estimate (6.7x10
(pg/kg/d) ), then the risks would be "at least" a factor of 2.3 lower than those presented in the table. The term "at
least" is used because, as discussed in Section 2.3 of this report, CPSC does not place the same emphasis on risks
calculated by the TEQ method as it does for 2,3,7,8-TCDD itself when estimating carcinogenic potency.
Group 1 includes accountants, auditors, architects, librarians, archivists, curators, and duplicating and nail/message
distribution occupations.
Group 2 includes lawyers, judges, computer prograimers, computer operators, records processors, managers, and those IB
miscellaneous administrative support occupations.
Group 3 includes secretaries, stenographers, and typists.
Group 4 includes teachers and sales representatives.
Group 5 includes medical workers who may come into contact with nonwoven products such as garments and masks.
21
-------
8941H-8
Table 5. Summary of Individual and Population Cancer Risks for Workers Involved
in Processing and Commercial Usage of Pulp and Paper Hill Sludge
Estimated risk3
No. of
Job category workers Exposure type
Sludge handling/processing
- Waste treatment plant operators 1300 Inhalation-volatilization0
Inhalation-particulate matter
Dermal6
- Sludge haulers/front-end loader
operators 400 Inhalation-volatilization0
Inhalation-particulate matter0
Dermal
Landfill ing operations
- Equipment operators 400 Inhalation-volatilization
Inhalation-particulate matter
Derma ld
Land application operations
- Equipment operators 20 Inhalation-volatilization
Inhalation-particulate matter
Dermal
Individual risk
Low
2xlO"12
(0.6)
2x1 O"11
(19)
IxlO'7
(19)
2xlO"U
(0.6)
IxlO'10
(19)
6x1 0~9
(19)
5xlO-10
(0.6)
IxlO'8
(19)
6xlO"9
(19)
3xlO"8
(0.6)
IxlO'6
(19)
IxlO'7
(19)
High
9xlO"9
(0.2)
7xlO"8
(8) 4
4xlO'a
(8)
2xlO'7
(0.2)
SxlO"7
(8)-5
3x10 b
(8)
2xlO'6
(0.2)
2xlO'5
(6)-5
1x10 s
(6)
9xlO'7
U)-5
6x10 s
(35)
7xlO'6
(35)
Population risk
It cases/vrl
Low High
2X10"11 9xlO"8
2xlO'10 7xlO'7
IxlO'8 4xlO"3
BxlO'10 5xlO"6
4xlO'9 2xlO"5
2xlO'7 8xlO~4-
5xlO"9 2xlO"5
IxlO"7 2xlO"4
6xlO'8 IxlO"4
-
IxlO'8 4xlO"7
5xlO"7 3xlO"5
5xlO"8 4xlO"6
22
-------
8941H-9
Table 5. (Continued)
Estimated risk
No. of
Job category workers
Exposure pathway
Individual risk
Low High
Population risk
(I cases/vr)
Low High
Composting operations
- Equipment operators
150
Inhalation-volatilization
1x10
-7
6x10
-6
5x10
-7
2x10
-5
Inhalat ion-part iculate matter
Derma ld
- Compost haulers 50 Inhalation-volatilization0
Inhalation-particulate matter0
Dermal
- Screen operators 20 Inhalation-volatilization
Inhalation-particulate matter
Dermal0
.
(0.2)
3xlO"7
(8) o
4xlO'9
(8)
3X10'10
(0.2)
3xlO'8
(8)
4xlO'9
(8)
IxlO'9
(0.20)
2xlO"6
(8)
2xlO"7
(8)
(0.2)
IxlO'5
(6)-7
2x10 '
(6)
IxlO'8
(0.2)
IxlO"6
'6)-7
2x10 '
(6)
7xlO'8
(0.2)
7xlO'5
(6)
8xlO"6
(6)
IxlO"6
2xlO'8
4X10'10
4x1 O"8
5xlO"9
7X10'10
9xlO"7
9xlO"8
4xlO"5
9xlO"7
2xlO~8
2x1 O"6
3xlO"7
3x1 O"8
4xlO"5
4x1 O"6
a EPA has classified 2,3,7,8-TCDD as a "B2" carcinogen. Values in parentheses represent percent exposure to 2.3,7.8-TCDD.
Risks presented were calculated using the EPA unit risk estimate for 2,3,7,8-TCDD and the TEQ method. This unit risk
estimate was derived using the EPA carcinogenic slope factor for 2,3,7,8-TCDD (1.6x10 (pg/kg/d) ). Had risks been
calculated using FDA's potency estimate (1.8x10 (pg/kg/d) ), then the risks and incidences would be a factor of
8.9 lower than those presented in the table. Had risks been calculated using CPSC's potency estimate (6.7x10
(pg/kg/d)'1), then the risks would be "at least" a factor of 2.3 lower than those presented in the table. The term "at
least" is used because, as discussed in Section 2.3 of this report, CPSC does not place the same emphasis on risks
calculated by the TEQ method as it does for 2,3,7,8-TCDD itself when estimating carcinogenic potency.
The frequency of exposure was assumed to be 250 days per year.
0 Duration of exposure assumed to be 4 hours per day.
duration of exposure assumed to be 1 hour per day.
e Duration of exposure assumed to be 2 hours per day.
Duration of exposure assumed to be 8 hours per day.
23
-------
protective equipment and engineering controls in this industry are not
well known. Therefore, the assessment assumed no use of protective
equipment (e.g., gloves and respirators) that could minimize potential
exposures.
Similarly, the frequency and duration of potential dermal and
inhalation exposures were not well characterized. Typical to reasonable
worst-case assumptions were used for these parameters in the assessment.
More accurate information could result in increased or decreased
individual risks.
The estimated population risks are very low even if the high
individual risk estimates are used as a basis. The highest estimated
risk is 0.2 excess cancer cases per year for a general worker involved in
paper converting operations. The next highest population risk is an
order of magnitude lower. One should note, however, that had mean or
median 2,3,7,8-TCDD TEQ concentrations rather than the highest
concentrations in the matrix of concern been used to predict population
risks, the predicted risks could be significantly lower; risks based on
the mean dioxin TEQ pulp level from the 104-Mill Study would have been 18
times lower.
2, SL -Summary of Risks Resulting from Use and Disposal of Pulp and
Paper Mill Sludge and Land Disposal of Paper
2.5.1 Introduction
This section summarizes estimates of human exposures and risks
associated with the use and disposal of sludge from kraft and sulfite
pulp and paper mills that employ chlorine bleaching and with the disposal
of paper wastes in municipal landfills. Exposures and risks associated
with the potential release into the environment of PCDDs/PCDFs from
incineration of sludge are summarized in Section 2.7 of this report. The
assessment of risks resulting from disposal and use of sludge and land
disposal of paper wastes is discussed in more detail in Chapter 5 of the
Background Document to the Integrated Risk Assessment. The following is
the major source document used in the Background Document: - ~
USEPA. 1990. U.S. Environmental Protection Agency. Assessment of
risks from exposure of humans, terrestrial and avian wildlife, and
aquatic life to dioxins and furans from disposal and use of sludge
from bleached kraft and sulfite pulp and paper mills. Washington,
DC: Office of Toxic Substances and Office of Solid Waste. EPA
560/5-90-013.
Conclusions drawn from this assessment are applicable only to pulp and
paper mill sludges. At this time, EPA has not assessed risks to human
health and the environment from the use and disposal of sludges generated
24
1578q
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at publicly and privately owned treatment plants that treat domestic
sewage. This evaluation, with potential subsequent regulation of sewage
sludges, will be performed in the next 2 to 3 years in the second round
of sewage sludge regulations under 40 CFR Part 503.
Using the Toxicity Equivalency Factor (TEF) values formally adopted
by the Environmental Protection Agency in 1987, 2,3,7,8-TCDD and
2,3,7,8-TCDF generally accounted for more than 90 percent of the dioxin
toxic equivalents (TEQ) found in samples of pulp and paper mill sludge
analyzed as part of the 5-Mill Study (USEPA 1988) and the 104-Mill Study
(Helms 1989). Consequently, risks estimated from disposal and use of
these types of sludges were based on exposures to these two dioxin
congeners. Table 6 presents the distribution of 2,3,7,8-TCDD and
2,3,7,8-TCDF sludge concentrations for all bleached kraft and sulfite
pulp and paper mills for which sludge concentrations were reported as
part of the 104-Mill Study (USEPA 1990).
Pulp and paper mill sludge management practices considered in this
assessment include landfilling, surface impoundment, land application,
and distribution and marketing. Approximately 2.5 million metric tons of
pulp and paper-mill sludge are generated annually. Table 7 presents
information from the 104-Mill Study regarding the amount of sludge
received annually for each pulp and paper mill sludge disposal and use
practice. Landfilling is the most common method of disposal of this
sludge, accounting for 44 percent of the total pulp and paper mill sludge
generated annually. About 75 percent of all mills that landfill pulp and
paper mill sludge dispose of this sludge on-site; the remaining 25 percent
dispose of the sludge in municipal landfills. Surface impoundment is the
next most common method of disposal of pulp and paper mill sludge account-
ing for 24 percent of the total pulp and paper mill sludge generated
annually. About 12 percent of the total pulp and paper mill sludge
generated annually is land-applied. Of the amount that is land-applied,
roughly 80 percent is applied to forest land, about 10 percent is applied
to reclaimed mine sites, and the remaining 10 percent is applied to land
used for agriculture. The amount of sludge incinerated is approximately
equal to the amount that is land-applied on an annual basis. About
8 percent of the total pulp and paper mill sludge generated annually was
reportedly distributed and marketed as a soil amendment (USEPA 1990).
2.5.2 Methodology
In assessing potential carcinogenic risks to the general population
from pulp and paper mill sludge management practices, 21 exposure
pathways were examined. The exposure pathways considered for each sludge
management practice are presented in Table 8. Two approaches were used
to estimate potential risks to the general population from exposure to
2,3,7,8-TCDD and 2,3,7,8-TCDF as a result of pulp and paper mill sludge
25
1578q
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8941H
Table 6. Distribution of 2,3.7,8-TCOO and 2,3,7,8-TCDF Sludge
Concentrations for All Plants in the 104-Mill Study3
2,3,7,8-TCDD 2.3,7,8-TCDF 2,3,7,8-TCDO 2.3,7,8-TCDF
Distribution concentration concentration Distribution concentration concentration
descriptor (ng/kg or ppt) (ng/kg or ppt) descriptor (ng/kg or ppt) (ng/kg or ppt)
100th percent ile
95th percent ile
90th percent ile
75th percent ile
50th percent ile
3.800
680
293
119
51
17.100
2,940
1,760
799
158
25th percent ile
10th percent ile
5th percent ile
Mean
Standard Deviation
12
3
1.9
162.9
464.7
34
6
2.4
885.4
2,303
aBased on data from 79 pulp and paper mills.
Source: USEPA (1990)
26
-------
8941H-21
Table 7. Use and Disposal Methods for Pulp
and Paper Mill Sludge
Pulp and paper
mill sludge Number of
disposal/use method mills
Landfill6 59
Surface impoundment 20
Land application0 7
Incineration 21
Distribution and marketing 7
Total 104
Quantity of
sludge received8 Percent
(dry tons/yr) of total
1,100,000 44
600,000 24
300,000 12
300.000 12
200,000 8
2,500,000 100
a Some plants use more than one sludge reuse or disposal method.
Where plants reported multiple sludge reuse or disposal methods,
reported quantities were divided among relevant categories.
About 75 percent of all mills that landfill pulp and paper mill
sludge dispose of sludge on-site; the remaining 25 percent dispose
of sludge in municipal landfills.
c Of the quantity of pulp and paper mill sludge that is land-
applied, roughly 80 percent is applied to forest land, about 10
percent is applied to reclaimed mine sites, and the remaining 10
percent is applied to land used for agriculture.
Not considered in this section; see Section 2.7.
27
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8941H-10
Table 8. General Population Cancer Risks Estimated Using Generic Exposure Scenarios Associated With
Each Pulp and Paper Mill Sludge Management Practice and with Disposal of Paper Wastes
Disposal practices/exposure pathway
Landfills
Ingest ion exposure from drinking surface water
contaminated by surface runoff (Percent TCDD)
Ingestion exposure from fish caught in surface
water contaminated by runoff (Percent TCDD)
Inhalation exposure to air contaminated
by volatilization from landfills (Percent TCDD)d
Ingestion exposure from drinking ground
water contaminated by leachate (Percent TCDD)
Surface Impoundments
Ingestion exposure from drinking surface water
contaminated by surface runoff (Percent TCDD)
Ingestion exposure from fish caught in surface
water contaminated by runoff (Percent TCDD)
Inhalation exposure to air contaminated by
volatilization from surface Impoundments
(Percent TCDD)d
Ingestion exposure from drinking ground
water" contaminated by leachate (Percent TCDD)
Distribution and marketing
Dermal exposure from contact with soil
(Percent TCDD)d
Exposure from direct ingest ion of soil
(Percent TCDD)d
Inhalation exposure to air contaminated
by volatilization from soil (Percent TCDD)d
MEI risk3
(lifetime*1)
7xlO~4
(0.6)
5xlO"2
(63)
4xlO"7
(4)
IxlO"9
(2)
2xlO"3
(0.6)
IxlO"1
(63)
IxlO'6
(0.6)
3xlO"8
(0.4)
1x10*"
(63)
IxlO'4
(57)
6xlO"7
(5)
Typical
risk3
(lifetime"1)
5xlO"8
(0.6)
8xlO"8
(65)
IxlO"9
(4)
IxlO"10
(8)
7xlO"8
(0.7)
IxlO"7
(65)
4xlO"8
(0.7)
5xlO-10
(0.7)
3xlO~8
(59)
3xlO"7
(56)
5x1 0~8
(6)
Exposed
population
6,980,000
14,200,000 .
12,800,000
19,000
2.330,000
4,760,000
7,100.000
6.000
3.500,000
3,500,000
3,500,000
Population
riskc
(cases/year)
5xlO"3
(0.6)
2xlO"2
(65)
2xlO"4
(4)
3xlO"8
(8)
2xlO"3
(0.7)
7xlO"3
(65)
4xlO"3
(0.7)
4xlO"8
(0.7)
IxlO"3
(59)
IxlO"2
(56)
3xlO"3
(6)
28
-------
8941H-11
Table 8. (Continued)
Disposal practices/exposure pathway
Inhalation exposure to soil particulates
(Percent TCDD)d
Dietary exposure from produce grown In gardens
(Percent TCDD)d
Land application
Dermal exposure from contact with soil
(Percent TCDD)d
Exposure from direct ingestion of soil
(Percent TCDD)d
Inhalation exposure to air contaminated by
volatilization from soil (Percent TCDD)d
Inhalation exposure to particulates from soil
(Percent TCDD)d
Ingestion exposure from drinking surface
water contaminated by surface runoff from
agricultural land application (Percent TCDD)
Ingestion exposure from drinking surface
water contaminated by surface runoff from
land application to mines/forests
(Percent TCDD)d
Ingestion exposure to fish contaminated by
surface runoff from agricultural land
application (Percent TCDD)d
Ingestion exposure to fish contaminated by
surface runoff from land application to
mines/forests (Percent TCDD)d
Dietary exposure from produce, meat, and dairy
products grown in sludge-amended soil
(Percent TCDD)d
MEI risk3
(lifetime"1)
2xlO"7
(64)
2xlO'8
(62)
4xlO"5
(62)
4xlO"5
(62)
2xlO"4
(4)
4xlO"6
(62)
2xlO"3
(0.6)
3xlO"3
(0.6)
IxlO"1
(63)
2X10"1
(63)
IxlO"2
(62)
Typical
risk3
(lifetime"1)
5xlO"9
(71)
5xlo-ll
(71)
3xlO"7
(65)
IxlO"6
(65)
IxlO"5
(4)
7xlo-7 -
(65)
3xlO"7
(0.6)
3xlO"7
(0.6)
5xlO"7
(65)
5xlO"7
(65)
2xlO"10
(65)
Exposed
population
3.500.000
3,500,000
40
40
40
40
333,000
833,000
679,000
1.700.000
240.000.000
Population-
risk6
(cases/year)
3xlO~4
(71)
3xlO"6
(71)
2xlO~7
(65)
7xlO"7
(65)
7xlO"6
(4)
4xlO"7
(65)
IxlO"3
(0.6)
4xlO"3
(0.6)
4xlO"3
(65)
IxlO"2
(65)
7xlO"4
(65)
29
-------
8941H-12
Table 8. (Continued)
Disposal practices/exposure pathway
Typical
MEI risk3 risk3
(lifetime'1) (lifetime"1)
Exposed
population
Population
riskc
(cases/year)
Ingestion exposure from drinking ground
water contaminated by leaching from soil
(Percent TCDD)d
<3xlO
(0.2)
-7
<3xlO
(0.2)
-7
NAe
NAe
Landfill disposal of paper wastes
Inhalation exposure from volatilization from <9xlO
municipal landfills in which paper is disposed:
(Percent TCDD)d (16)
Ingestion exposure from drinking groundwater <2xlO
contaminated by leachate from municipal landfills
in which paper is disposed:
(Percent TCDD)d (53)
-7
-9
<9xlO
(16)
<2xlO
(53)
-7
-9
NAe
NAe
18,500,000 <4xlO
(53)
-4
EPA has classified 2,3,7,8-TCDD as a "B2" carcinogen. Risks presented were calculated using the EPA unit risk estimate
for 2,3,7,8-TCDD and the TEQ method. This unit risk estimate was derived using the EPA carcinogenic slope factor for
2,3,7,8-TCDD (1.6xlO~4 (pg/kg/d)"1). Had risks been calculated using FDA's potency estimate (l.SxlO"5
(pg/kg/d) ), then the risks and incidences would be a factor of 8.9 lower than those presented in the table. Had
risks been calculated using CPSC's potency estimate (6.7x10 (pg/kg/d)"), then the risks would be "at least" a
factor of 2.3 lower than those presented In the table. The term "at least" 1s used because, as discussed in Section 2.3
of this report, CPSC does not place the same emphasis on risks calculated by the TEQ method as it does for 2,3,7,8-TCDD
itself when estimating carcinogenic potency.
Estimates of exposed population are based on typical risk.
Calculated as: [Typical Risk x Exposed Population] / [Life Expectancy].
All percent TCDD values are indicated in parentheses in the table:
[Exposure to TCDD1
Calculated as: 100 x'
[Exposure to TCDD] + (1/10) [Exposure to TCDF]
NA = Not applicable.
Source: USEPA 1990.
30
-------
management practices. The primary difference in these two approaches is
the distribution of pulp and paper mill sludge concentrations of
2,3,7,8-TCDD and 2,3,7,8-TCDF used to estimate risks.
One approach used the distribution of concentrations of 2,3,7,8-TCDD
and 2,3,7,8-TCDF reported in the 104-Mill Study data base to be present
in sludge for each management practice to estimate risks to the general
population from each pulp and paper mill sludge management practice
considered (USEPA 1989c, 1990). In the future, however, these mills
could employ sludge management practices different from those reported in
the 104-Mill Study data base. The distribution of 2,3,7,8-TCDD and
2,3,7,8-TCDF concentrations in pulp and paper mill sludge handled by each
management practice could change, and the estimates of risks from these
practices would, therefore, also change. Consequently, a second approach
based on the distribution of sludge concentrations of 2,3,7,8-TCDD and
2,3,7,8-TCDF from all pulp and paper mills in the 104-Mill Study data
base was used to assess risk to the general population from each sludge
management practice.
Using the second approach, these practices could be compared so that
those with which the highest risks were associated could be determined
without considering the influence of differences in concentrations of
2,3,7,8-TCDD and 2,3,7,8-TCDF in pulp and paper mill sludge. This second
approach, also referred to as the "generic" approach, estimated typical
individual risks based on mean concentrations of 2,3,7,8-TCDD and
2,3,7,8-TCDF in sludge and estimated maximum exposed individual (MEI)
risks based on 90th percentile concentrations of these two dioxin
congeners. The mean and 90th percentile concentrations of 2,3,7,8-TCDD
in pulp and paper mill sludge were 163 ppt and 293 ppt, respectively; the
mean and 90th percentile concentrations of 2,3,7,8-TCDF were 885 ppt and
1,760 ppt, respectively (USEPA 199.0).
Various mathematical models were used to estimate concentrations of
2,3,7,8-TCDD and 2,3,7,8-TCDF in environmental media. These include the
Seasonal Soil (SESOIL) model for fate and transport in soil (Bonazountas
and Wagner 1984); the Analytical Transport One-, Two-, and Three-
Dimensional (AT123D) model for fate and transport in aquifers (Yeh 1981);
and the Industrial Source Complex Long-Term (ISCLT) dispersion model for
fate and transport in air (Bowers et al. 1980). A detailed discussion of
the methods and assumptions used to estimate environmental releases and
concentrations of 2,3,7,8-TCDD and 2,3,7,8-TCDF from pulp and paper mill
sludge in environmental media is provided in the risk assessment for
disposal and use of pulp and paper mill sludge prepared under the
guidance of the Office of Toxic Substances and the Office of Solid Waste
of the U.S. Environmental Protection Agency (USEPA 1990).
31
1578q
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2.5.3 Results and Discussion
Three types of potential carcinogenic risks were estimated: maximum
exposed individual (MEI) risks, typical individual risks, .and population
risks. Estimates of potential general population cancer risks associated
with each pulp and paper mill sludge management practice are presented in
Table 8. These estimates were based on the generic approach. In
general, risks estimated by the two approaches differed by no more than
an order of magnitude. In all cases, exposure to 2,3,7,8-TCDF was
assumed to be one-tenth the exposure to 2,3,7,8-TCDD based on the
toxicity equivalency factor method (USEPA 1989a). Estimates of risks
were based on the EPA slope factor of 1.6 x 10"* (pg/kg-day)"1.
Estimates of potential MEI risks exceeded 1 x 10~6 for 15 of the 21
exposure pathways examined. The exposure pathway with the greatest
potential MEI risk was ingestion of fish from surface water contaminated
by runoff from landfills, surface impoundments, and land application
sites. Estimates of MEI risk from this pathway ranged from 10"1 to
10~2. Ingestion of surface water contaminated by runoff from
landfills, surface impoundments, and land application sites resulted in
MEI risks on the order of 10"3. For land application of pulp and
paper mill sludge, the second highest MEI risk resulted from ingestion of
produce, meat, and dairy products grown on sludge-amended soil; the MEI
risk estimated from this pathway was roughly 10~2. The subsistence
farmer (i.e., farmer that grows all or almost all food required by the
farm family) represented the MEI for this exposure pathway. Most of the
exposure pathways examined for land application of pulp and paper mill
sludge resulted in MEI risks greater than 1 x 10"6.
The only typical individual risk estimated to be greater than 10"6
occurs as the result of inhalation of dioxin vapors from sludge applied
to agricultural land; the typical individual risk estimated from this
exposure pathway was on the order of 10"5. Population risks for
pathways with typical individual risks greater than 10"6 were
estimated to be very low because of the small population sizes associated
with these estimates of typical risk. As with the MEI risk estimates,
consumption of fish from surface water contaminated by surface runoff
poses the highest population risk because of the large number of people
potentially exposed; the population risk estimated from this exposure
pathway was on the order of 10~2 excess cancer cases per year.
Because of a lack of site-specific data, hypothetical scenarios were
examined; there is no direct evidence that the MEI exposure scenarios
depicted actually occur. Because scant information was available
regarding sludge management practices at sites receiving pulp and paper
mill sludge, estimates of potential individual risk were based on
exposure scenarios that depicted poor sludge management practices. For
example, estimates of both typical and MEI risks assumed that runoff from
landfills and surface impoundments was not controlled and would enter
32
1578q
-------
receiving streams used as sources of drinking water and fish ingested by
humans. More sound management practices would tend to mitigate these
risks. Also, because -the location and hydrogeologic characteristics of
the sites are not well known, generic data were used for parameters on
the topography and geology of each site, the hydrology of nearby surface
water bodies, the distance of each site from surface water, the land area
of each site, and the quantity of sludge received at each site. Values
assumed for these parameters in each typical scenario were different from
those used in each MEI scenario. Assumptions used for each scenario to
determine typical individual and MEI risks are presented in the risk
assessment for disposal and use of pulp and paper mill sludge (USEPA
1990).
2.6 Summary of Risks to Humans from Wastewater Discharges
2.6.1 Introduction
The assessment of risks to humans from discharge of pulp and paper
mill effluents is discussed in more detail in Chapter 6 of the Background
Document to the Integrated Risk Assessment. The major source documents
used in the Background Document for this chapter are the following:
USEPA. 1990. U.S. Environmental Protection Agency. Risk assessment
for 2,3,7,8-TCDD and 2,3,7,8-TCDF contaminated receiving waters from
U.S. chlorine-bleaching pulp and paper mills. Washington, DC:
Office of Water Regulations and Standards, U.S. Environmental
Protection Agency. August 1990.
USFDA. 1990. U.S. Food and Drug Administration. Carcinogenic risk
assessment for dioxins and furans in fish contaminated by
bleached-paper mills. Report of the Quantitative Risk Assessment
Committee. Washington, DC: U.S. Food and Drug Administration.
January 19, 1990.
Exposure pathways considered in this assessment include ingestion of
untreated water downstream from pulp and paper mill effluents and
ingestion of fish caught in the vicinity of pulp and paper mill
effluents. Risks from ingestion of contaminated fish were estimated for
average individuals who eat fish and for sports and subsistence fishers.
2.6.2 Methodology
Three approaches were used to estimate and compare exposures of
humans to 2,3,7,8-TCDD and 2,3,7,8-TCDF from consumption of fish that may
be contaminated by effluent discharges from pulp and paper mills. In the
first approach, a simple dilution model was used by EPA to estimate
in-stream contaminant concentrations and fish tissue residues downstream
from each of the 104 pulp and paper mills that use chlorine as a
33
1578q
-------
bleaching agent. The highest estimated steady-state in-stream
concentrations in the immediate downstream vicinity of the mills
(assuming fully mixed conditions) were used to estimate exposure to
fish. Mill-specific 5-day effluent composite concentrations of
2,3,7,8-TCDD and 2,3,7,8-TCDF collected as part of the 104-Mill Study
were used for these calculations. (It is not known how representative
these samples are of long-term mill discharges; also, any changes in
effluent concentrations resulting from recent changes in mill processes
or operations are not reflected in these data.) Similarly, mill-specific
receiving stream flow rates (i.e., harmonic mean flow or zone of initial
dilution information) were used in the calculations. It was assumed that
100 percent of the in-stream contaminants (both dissolved
and adsorbed to suspended solids) are bioavailable to fish and that fish
tissue bioavailability to humans ingesting fish is 95 percent.
The second approach used the Exposure Assessment Modeling System
(EXAMS II) to partition the site-specific in-stream steady-state water
column contaminant concentrations between dissolved and particulate
forms. However, only the dissolved contaminant concentration predicted
by EXAMS II was considered in determining exposure and risk. Because no
comprehensive studies on 2,3,7,8-TCDD and 2,3,7,8-TCDF accumulation in
sediments and bioaccumulation up the food chain exist, no attempt was
made in the EXAMS II approach to estimate fish exposure to contaminants
associated with suspended particulates, bed sediments, or the food chain.
For the third approach, FDA used actual measured residues of
2,3,7,8-TCDD and 2,3,7,8-TCDF in fish collected near pulp and paper mills
as part of EPA's National Bioaccumulation Study (USEPA 1989b). FDA
combined the data to develop an average fish tissue TEQ concentration,
which was then used to estimate generic exposures and risks.
Tissue residue levels for fish exposed to the in-stream contaminant
concentrations estimated by the first and second approaches were
calculated by multiplying the highest in-stream contaminant concentration
by estimated bioconcentration factors (BCFs) for 2,3,7,8-TCDD and
2,3,7,8-TCDF. BCFs of either 5,000 or 100,000 (for 2,3,7,8-TCDD) and
3,900 (for 2,3,7,8-TCDF) were used. The BCF for 2,3,7,8-TCDD of 5,000 is
based on fish fillet residue levels, not whole body levels, and is the
value currently used in EPA's Ambient Water Quality Criteria for
2,3,7,8-TCDD; the second BCF of 100,000 was developed primarily from the
results of EPA Duluth Laboratory's recent studies on the bioconcentration
of 2,3,7,8-TCDD by fish. The BCF for 2,3,7,8-TCDF is based on the
geometric mean of the three measured BCF values for whole body levels
reported in a recent literature review (Nabholz 1989). The BCFs (100,000
for 2,3,7,8-TCDD and 3,900 for 2,3,7,8-TCDF) developed from more recent
studies were for whole body levels; to obtain estimates of levels in the
edible portion of the fish, whole body levels were divided by 2,
resulting in effective BCFs of 50,000 for 2,3,7,8-TCDD and 1,950 for
2,3,7,8-TCDF.
34
1578q
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Human exposures and risks resulting from ingestion of contaminated
fish were calculated for several fish consumption rates:
6.5 g/day (EPA--estimated average fish/shellfish consumption in
U.S.);
13 g/day (FDAestimated average consumption by sports fishers);
30 g/day (EPA--estimated typical consumption by sports fishers);
39 g/day (FDAestimated 90th percentile consumption by sports
fishers);
69 g/day (FDA--estimated average consumption by subsistence
fishers);
116 g/day (FDAestimated 90th percentile consumption by
subsistence fishers); and
140 g/day (EPA--estiamted high consumption rate for subsistence
fishers or other high-rate consumers).
A typical drinking water ingestion rate of 2 I/day was used to
estimate human exposures through ingestion of contaminated drinking
water. It was assumed that the water consumed is taken from the point of
highest in-stream pollutant concentration after the effluent is fully
mixed in the receiving stream and that the water is not treated to remove
contaminants prior to ingestion.
2.6.3 Results and Discussion
Table 9 presents the estimated cancer risks associated with human
consumption of contaminated fish. In terms of risks of non-cancer
effects, the results of the EPA analysis indicate that discharges from
27 percent of mills could cause toxic liver effects upon ingestion of one
4-ounce fish serving, assuming an effective BCF of 50,000 for edible
tissues compared to a 1-day health advisory dose of 100 pg/kg/day
(estimated by EPA for the purpose of this assessment); assuming a BCF of
5,000, only 5 percent of the mills could cause liver effects. A higher
percentage of mills discharge effluent that may cause reproductive
effects from long-term, low-level exposure, based on a reference dose of
1 pg/kg/day estimated by EPA for the purpose of this assessment.
Similarly, the FDA analysis indicated that subsistence fishers could be
at risk for reproductive effects.
With regard to drinking water risks, use of the simple dilution method
estimates that the cancer risks associated with the 69 mills evaluated
range from 10'4 to 10"10. The greatest percentage of these
mills (23 mills or 33 percent) are associated with risk levels within the
35
1578q
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8941H-4
Table 9. Estimated Cancer Risks Associated with Consumption of
Contaminated Fish
Agency
EPA
EPA
Consumer
Method type
Site-specific Average
Site-specific Sports
2,3,7,8-TCDD
BCFa Approach
5,000 Simple dilution
EXAMS II
100,000 Simple dilution
EXAMS II
Upper bound
cancer risk
(lifetime"1)
10"8 to 10"2
10"8 to 10"3
lO^to^lO"1
10"7 to >10"1
FDA Generic Sports NA
EPA Site-specific Subsistence 100,000
FDA
Generic
Subsistence NA
NBS Data
Simple dilution
EXAMS II
NBS Data
10"5 to 10"3
10
10
"6
"6
10"4 to 10"3
a The BCF of 5,000 for 2,3,7,8-TCDD is based on edible tissue residue levels. The BCF of
100,000 is based on whole body residue levels; to obtain estimates of levels in the edible
portion of fish, this whole body BCF was divided by a factor of 2 resulting in an effective
BCF of 50,000. Similarly, for 2.3.7,8-TCDF, a whole body residue BCF of 3,900 was adjusted
by a factor of 2 to obtain an effective BCF of 1,950.
EPA classifies 2,3,7,8-TCDD as a "B2" carcinogen. Risks presented were calculated using
the TEF method; EPA estimates of risks are based on the carcinogenic slope factor estimate
for 2,3,7,8-TCDD of 1.6 x 10"4 (pg/kg/day)"1; FDA estimates are based on an estimated
carcinogenic slope factor of 1.8 x 10 (pg/kg/day) .
NA = Not applicable.
36
-------
10"6 range. Use of the EXAMS II water column method estimates that the
risk levels associated with the 64 mills evaluated using this method range
from 10'5 to 10~9. Fifty of these mills (78 percent) are
associated with risk levels in the 10'6 (18 mills) to 10'7
(32 mills) range. These results are likely overestimates of human health
risks because of the conservative assumptions made concerning no
treatment of the water and ingestion of water at the point of highest
in-stream concentration.
In evaluating the risks estimated in this assessment for ingestion of
contaminated fish, it should be noted that BCFs are highly species
specific. Using a single BCF does not take into account interspecies
differences in the rate and degree of contaminant bioconcentration. For
example, a study conducted by Cook et al. (1989) indicates that a BCF of
200,000 for whole body levels, which is higher than the upper limit used
in this study (i.e., 100,000), may be applicable for 2,3,7,8-TCDD for
some species of fish. EPA used two BCF values for whole body levels,
5,000 and 100,000 (50,000 for edible tissue), to put bounds on the
probable range of bioconcentration by aquatic organisms.
The assumed fish tissue consumption rates also have an impact on
results of this assessment. The fish tissue consumption rate of
6.5 g/day (or less than two 4-ounce meals per month) is considered an
average level of fish and shellfish consumption by the general population
in the United States. However, this consumption rate does not reflect
the consumption rate of subsistence or sports fishers.
The predictions from the EPA assessment also do not take into
consideration the mobility of fish in the receiving waters. Both
resident and migrating species will move in and out of the discharge
area. The first two EPA assessment approaches assume that the fish
remain exposed to the predicted contaminant concentration up to the time
they are caught, thus resulting in a conservative estimate of aquatic
life impacts and human health risk. However, because there is strong
agreement between monitored fish tissue levels (i.e., the National
Bioaccumulation Study results) and modeled fish tissue levels, there is a
high degree of confidence that fish downstream from pulp and paper mills
are being contaminated and that humans consuming these fish at regular
intervals are at risk.
It should also be noted that the assumptions made in this assessment
regarding BCF, fish consumption rates, stream flow rates, and
bioavailability may overestimate or underestimate risks compared to risks
estimated in State risk assessments.
Taking into account the above assumptions, simplifications, and
limitations, the results of this assessment indicate the potential exists
for high levels of 2,3,7,8-TCDD and 2,3,7,8-TCDF contamination in the
37
1578q
-------
water column resulting from surface water effluent discharges from many
of the chlorine-bleaching pulp and paper mills investigated. These
predicted contaminant concentrations could represent significant
implications for human health.
2.7 Summary of Risks Resulting from Pulp and Paper Hill Sludge
Incineration
2.7.1 Introduction
The assessment of risks to humans from incineration of pulp and paper
mill sludge is discussed in more detail in Chapter 7 of the Background
Document to the Integrated Risk Assessment. The primary source document
used for this chapter in the Background Document is as follows:
Dusetzina M. 1989. Human health exposure and risk assessment for
dioxins-pulp/paper waste water sludge incineration-subtask 5.
Washington, DC: U.S. Environmental Protection Agency, Office of Air
Quality Planning and Standards.
2.7.2 Methodology
Dusetzina (1989) used air dispersion modeling (i.e., HEM-Human
Exposure Model) to predict potential inhalation exposures to CDDs/CDFs to
populations surrounding each of the 21 pulp and paper mills that reported
employing incineration as a wastewater sludge disposal method in the
104-Mill .Study. The estimated exposures were used to predict both
maximum exposed individual (MEI) cancer risks and aggregate (or
population) risks.
Information used to estimate potential emissions (i.e., input to the
air dispersion model) included the following:
(1) Combustor and flue gas characteristics of power boilers at 16 of
the 21 pulp and paper mills incinerating wastewater sludges.
Information used included flue gas temperature, flue gas volume,
stack height, stack diameter, residence time above 1,800°F
in the combustor, type of air pollution control device, air
pollution control device operating temperature, and annual
operating time of the combustor spent burning sludge.
(2) Dioxin and furan emission test results from a pulp and paper
mill power boiler at Cloquet, Minnesota, which co-combusted
wastewater sludge.
(3) Wastewater sludge characteristics as reported in the 104-Mill
Study, such as sludge quantity and 2,3,7,8-TCDD and 2,3,7,8-TCDF
concentrations, from facilities that disposed of their sludge by
incineration.
38
1578q
-------
Two methods were used to estimate emissions of CDDs/CDFs to air. The
first method estimated emissions by assuming that the CDD/CDF
concentrations in the stack flue gas of each power boiler were the same
as the maximum measured stack gas concentrations from the one facility
tested. Annual emissions were estimated by prorating the emissions based
on the flue gas volumes and operating hours for each facility. The
second method assumed that all 2,3,7,8-TCDD/TCDF contained in the
wastewater sludge was emitted to the atmosphere. The use of the latter
method to estimate emissions resulted in estimated emissions 700 to
700,000 times greater than the emission based on the stack gas monitoring
data. The latter method does not consider the potential for CDD/CDF
formation as products of incomplete combustion (PIC).
2.7.3 Results and Discussion
The estimate of the MEI risk using the first method (i.e., stack gas
method) was 1.2 x 10~10, which occurred at the Longview,
Washington, facility. The second method (i.e., the sludge concentration
method) estimated the MEI risk to be highest at the Pine Bluff, Arkansas,
facility (9.3 x 10~7). Estimated population risks were very low.
The highest predicted annual incidence, at any facility was 0.0002. Table
10 presents the predicted MEI and population risks for each facility.
These two methods were used to assess risks for several reasons.
Relevant, although limited, data were used in each method. Although the
stack gas concentration data were more limited (stack gas concentrations
were available at only one stack) than the concentration data for
2,3,7,8-TCDD/TCDF in sludge, these were probably more relevant since
destruction efficiency, partitioning to fly ash and bottom ash, and
distribution of CDDs/CDFs in gaseous and particulate phases did not have
to be characterized. Uncertainties regarding these parameters are
important for the .sludge concentration method. One major problem
associated with the stack gas method was, of course, the limited data.
Questions concerning secondary formation of CDDs and CDFs as products of
incomplete combustion and effectiveness of control devices, particularly
if a significant .fraction of the CDDs/CDFs are in a gaseous phase, are
important for the sludge concentration method.
The Office of Air Quality Planning and Standards (OAQPS) contends
that the first method (i.e., the stack gas method) provides a better
estimate of the performance of the boilers used at the 21 pulp and paper
mill facilities that incinerate sludge than the worst-case estimates from
the second method, which assumes no destruction of CDDs/CDFs in the
sludge feed. The sludge charged to the power boiler for which stack gas
concentration data are available uses a high sludge feed content (10 to
15 percent of feed) relative to the feed content used by the other
facilities (2 to 17 percent) and therefore may represent an over-
estimation of typical emissions. The second method (i.e., the sludge
39
1578q
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8941H-13
Table 10. Combined Dioxin/Furan Risks and Annual Incidence3
Maximum individual risk
Sludge Stack gas
cone, method
Location (xlO~7)
Pine Bluff, AR
Port Angeles, WA
Longview, WA
Texarkana, TX
Everett. WA
Lewiston, ID
Houston, TX
Moss Point, MS
Westbrook, ME
Georgetown, SC
Ketchikan, AK
Roaring Springs, PA
Tacoma, WA
West Point, VA
Hinckley, ME
Claiborne, AL
Jackson, AL
Cloquet, MN
Mobile, AL
Hoquiam, WA
Sitka. AK
9.3
3.1
2.5
1.8
1.4
1.4
1.2
0.95
0.16
0.15
0.15
0.12
0.11
0.056
0.049
0.049
0.039
0.038
0.025
0.021
0.012
method
(xlO'7)
0.000055
0.00026
0.0012
0.000042
0.00029
0.000053
0.000055
0.000049
0.000021
0.000044
0.000045
0.00011
0.000037
0.000029
0.000011
0.000012
0.000029
0.0000035
0.000057
0.000056
0.0000091
Annual incidence
Sludge
cone, method
0.00015
0.000013
0.000027
0.000098
0.000042
0.0000097
0.0002
0.000012
0.000014
0.0000016
<0. 000001
0.0000015
0.000034
<0. 000001
0.0000027
<0. 000001
<0. 000001
<0. 000001
0.0000023
<0. 000001
<0. 000001
Stack gas
method
<0. 000001
<0. 000001
<0. 000001
<0. 000001
<0. 000001
<0. 000001
<0. 000001
<0. 000001
<0. 000001
<0. 000001
<0. 000001
<0. 000001
<0. 000001
<0. 000001
<0. 000001
<0. 000001
<0. 000001
<0. 000001
<0. 000001
<0. 000001
<0. 000001
a EPA classifies 2,3,7,8-TCDD as a "B2" carcinogen. Risks presented were
calculated using the EPA unit risk estimate for 2,3,7,8-TCDD and the TEQ
method. This unit risk estimate was derived using the EPA carcinogenic
potency estimate for 2,3,7,8-TCDD (1.6 x 10'4 (pg/kg/d)"1). Had risks been
calculated using FDA's potency estimate (1.8 x 10 (pg/kg/d) ),
then the risks and incidences would be a factor of 8.9 lower than those pre-
sented in the table. Had risks been calculated using CPSC's potency estimate
(6.7 x 10"5 (pg/kg/d)"1), then the risks would be "at least" a factor of
2.3 lower than those presented in the table. The term "at least" is used be-
cause, as discussed in Section 2.3 of this report, CPSC does not place the same
emphasis on risks calculated by the TEQ method as it does for 2,3,7,8-TCDD
itself when estimating carcinogenic potency.
40
-------
concentration method), although more conservative since no destruction of
CDDs/CDFs is assumed, does not account for secondary formation of
CDDs/CDFs as products of incomplete combustion.
2.8 Summary of Risks Resulting from Use of and Consumer Body Contact
with Paper Products Under CPSC Jurisdiction
2.8.1 Introduction
This section summarizes estimated human exposure and risks resulting
from the use of consumer paper products containing 2,3,7,8-TCDD and
2,3,7,8-TCDF. The assessment of risks resulting from use of and consumer
body contact with paper products is discussed in greater detail in
Chapter 8 of the Background Document to the Integrated Risk Assessment.
The major source document for this chapter in the Background Document is
the following:
Babich MA. 1989. CPSC staff assessment of the risks to human health
from exposure to chlorinated dioxins and dibenzofurans in paper
products. Memorandum from Dr. Michael A. Babich (CPSC) to Lois
Dicker (EPA/OTS). January 25, 1990.
2.8.2 Methodology
The paper products considered in Babich (1989) were limited to
products under CPSC jurisdiction (see Table 11). They were divided into
product categories, depending on the assumed exposure mechanism.
Exposure was assumed to occur by means of either liquid mediated exposure
or dry contact. Products involving liquid-mediated absorption included
disposable infant diapers, paper towels, facial tissue, and toilet
tissue. Paper towels were further divided into two scenarios, drying
hands and household cleaning. Exposure by means of contact with dry
paper included paper napkins and communication paper (i.e., uncoated
sheets such as bond paper, books, magazines, and newsprint). Exposure to
communication paper was assessed for exposures at home and in school.
Dermal exposure was treated as a two-step process: (1) migration or
extraction of dioxin from paper or pulp into a liquid contacting the skin
or to the surface of the skin itself, followed by (2) percutaneous
absorption. The migration step may occur by either of two general
mechanisms, liquid-mediated extraction or skin contact with dry paper
(unmediated diffusion).
The industry average concentrations of 2,3,7,8-TCDD and 2,3,7,8-TCDF
reported for pulp in the 104-Mill Study were used to estimate dermal
exposures for all products except disposable diapers. For diapers, the
average concentrations of 2,3,7,8-TCDD and 2,3,7,8-TCDF reported for pulp
in the 104-Mill Study for those mills that produce pulp specifically for
disposable diapers were used.
41
1578q
-------
3941H-17
Table 11. Individual Lifetime and Population Cancer Risks from 2,3,7,8-TCDO and 2,3,7,8-TCDF in Consumer Paper Products
ro
2,3.7.8-TCDD TEQ
LADD LADD
Product (pg/kg/d) (pg/kg/d)
Superabsorbent Diapers 2.4xlO"7 6.8x10
Conventional Diapers 1.7xlO"6 S.OxlO"6
Paper Towels 7.1xlO"6 l.lxlO"5
(Hand Drying)
Paper Towels 2.3xlO"5 S.lxlO"5
(Cleaning)
Facial Tissue l.SxlO"7 5.6xlO"7
(Normal Use)
Facial Tissue 7.2xlO"6 1.6xlO"5
(Makeup Removal)
Toilet Tissue S.OxlO"6 l.lxlO"5
(Males)
Toilet Tissue 1.4xlO"5 5.2xlO"5
(Females)
Communication Paper 5.8x10" 1.3x10"
(Homes)
Communication Paper 6.8x10" >1.5xlO
(School)
Paper Dinner Napkins 2.3xlO"6 S.lxlO"6
Lifetime
CPSC
2.1xlO"U
(100)
l.SxlO'10
(100)
6.3xlO"10
(100)
2.1xlO"9
(100)
1.2xlO"U
(100)
6.4xlO"10
(100)
2.7xlO"10
(100)
1.2xlO"9
(100)
S.lxlO"10
(100)
e.ixio-10
(100)
2.1xlO"10
(100)
individual cancer
EPA
2.0xlO~10
(35)
1.4xlO"9
(35)
S.lxlO"9
(64)
l.SxlO"8
(45)
1.6X10'10
(23)
4.6xlO"9
(45)
S.lxlO"9
(22)
l.SxlO"8
(22)
3.7xlO"9
(45)
4.3xlO"9
(45)
1.4xlO"9
(45)
c
risk
FDA
2.2xlO"H
(35)
1.6X10"10
(35)
3.6xlO-10
(64)
1.6xlO"9
(45)
l.SxlO"11
(23)
5.2xlO"10
(45)
S.exlO"10
(22)
1.7xlO"9
(22)
4.2xlO"10
(45)
4.9xlO"10
(45)
1.7xlO"10
(45)
Excess cancers per vear
Exposed
population CPSC EPA FDA
.
1.0xl07d 0.00002 0.0002 0.00002
2.4xl08 0.002 0.011 0.001
2.4xl08 0.007 0.051 0.005
1.2xl08 0.00002 0.0003 0.00003
1.2xl08 0.001 . 0.008 0.0009
1.2xl08 0.0005 0.005 0.0006
1.2xl08 0.002 0.026 0.003
2.4xl08 0.002 0.013 0.001
2.4xl08 0.002 0.015 0.002
2.4xl08 0.0007 0.005 0.0006
-------
8941H-18
Table 11. (continued)
2.3,7,8-TCDD
LADD
Product (pg/kg/d)
All Products (Male)3 S.OxlO"5
All Products (Female)b 6.8xlO"5
c
TEO Lifetime individual cancer risk Excess cancers per year
LADD
(pg/kg/d) CPSC
l.lxlO"4 4.5xlO"9
(100)
1.6xlO~4 G.lxlO"9
(100)
EPA
3.2xlO"8
(45)
4.6xlO"8
(45)
Exposed
FDA population CPSC
3.5xlO"9 1.2xl08 0.008
(45)
5.2xlO"9 1.2xl08 0.010
(45)
EPA FDA
0.055 0.006
0.079 0.009
a Includes all products except superabsorbent diapers, facial tissues (makeup removal), and toilet tissue (females).
Includes all products except superabsorbent diapers and toilet tissue (males).
c EPA classifies 2,3,7,8-TCDD as a "62" carcinogen. Numbers in parentheses are the percent of estimated risk due to 2,3,7,8-TCDD.
Assumes use only of conventional diapers. Resident population age 0 to 3 years.
co
-------
2.8.3 Results and Discussion
The exposures and individual cancer risks estimated to result from
2,3,7,8-TCDD and 2,3,7,8-TCDD in consumer paper products under CPSC juris-
diction are summarized in Table 11. Estimates of individual cancer risk
(using CPSC's cancer potency estimate) range from 1 x 10'11 (i.e.,
10 per trillion) for facial tissues (normal use scenario) to 2 x 10~9
(i.e., 2 per billion) for paper towels. For all products combined, the
individual risk is estimated to be 5 x 10~9 (i.e., 5 per billion).
Use of the EPA cancer slope factor and TEQ method for assessing toxicity
of 2,3,7,8-TCDF results in slightly greater risks. Use of the FDA cancer
slope factor and TEQ method results in slightly lower risks.
Excess cancer risks per year in the U.S. population are also
presented in Table 11. Less than one cancer case per year is expected to
occur from 2,3,7,8-TCDD and 2,3,7,8-TCDF in consumer paper products.
Additivity was assumed in combining risks from different products or
different scenarios.
The average daily dose (ADD) values estimated for all products are
well below the estimated health advisory level for protection against
liver toxicity (10 days at 10 pg/kg/d) that was developed by EPA for the
purposes of this assessment. Thus, the hazard index is much less than
one, indicating that the risk for non-cancer effects is absent or, at
most, trivial. ADD values and hazard index values are given in Table 12
for all products.
Numerous conservative but not unreasonable assumptions were used to
perform this assessment. These included: (1) use of matrix/solution
equilibrium partitioning coefficients for 2,3,7,8-TCDD/TCDF in assessing
short-duration exposures even though equilibrium may not be reached in
these short durations; (2) use of data on 2,3-dibromo-l-propanol
phosphate (TRIS) transfer from cloth to skin to simulate transfer of
2,3,7,8-TCDD/TCDF from paper to skin; (3) use of correction factors to
account for the effect of anatomic site, diseased/damaged skin, and
individual age on percutaneous absorption; and (4) use of results of in
vitro studies with human skin of percutaneous absorption of
2,3,7,8-TCDD. However, even with the use of conservative assumptions,
the predicted cancer and non-cancer risks were negligible.
2.9 Summary of Risks Resulting from the Use of Pulp-Containing
Medical Devices Under FDA Jurisdiction
2.9.1 Introduction
This section summarizes estimated human exposure and risk associated
with the use of medical devices containing bleached wood pulp. Examples
of medical devices believed to contain bleached wood pulp include scented
and unscented menstrual pads and tampons, alcohol pads, surgical apparel,
44
1578q
-------
8941H-19
Table 12. Risks of Non-Cancer Adverse Effects from 2,3,7,8-TCDD and
2,3,7,8-TCDF in Consumer Paper Products
Product
Superabsorbent Diapers
Conventional Diapers
Paper Towels (Hand
Drying)
Paper Towels
(Cleaning)
Facial Tissue
(Normal Use)
Facial Tissue
(Makeup Removal)
Toilet Tissue
(Males)
Toilet Tissue
(Females)
Communication Paper
(Home)
Communication Paper
(School)
Paper Dinner Napkins
2,3,7,8-TCDD
ADDa
(pg/kg/d)
5.3xlO"6
4.0xlO~5
7.1xlO"6
2.3xlO~5
l.SxlO"7
l.OxlO"5
3-OxlO"6
1.4xl(f5
7.7xl(T6
4.0xlO~5
2.3xlO"6
TEQ
ADD3
(pg/kg/d)
l.SxlO"5
1.2xlO~4
l.lxlO"5
S.lxlO"5
5.6xlO~7
2.2xlO"5
-
l.lxlO"5
5.2xlO~5
1.7xlO"5
8.8xlO~5
S.lxlO"6
2,3,7.8-TCDD
Hazard
Indexb
S.SxlO"7
4.0xlO"6
7.1xlO"7
2.3xlO~6
l.SxlO"8
l.OxlO"6
3-OxlO"7
1.4xlO"6
7.7xlO"7
4.0X10"-6
2.3xlO"7
TEQ
Hazard
Indexb
l.SxlO"6
1.2xlO"5
l.lxlO"6
S.lxlO"6
5.6xlO"8
2.2xlO"6
l.lxlO"6
5.2xlO"6
1.7xlO"6
8.8xlO"6
S.lxlO"7
a ADD is the average daily dose during the period of exposure.
b The hazard index is the ratio of ADD to the EPA 10-day health advisory of
10 pg/kg/d.
45
-------
medical absorbent fiber, and examination gowns. The assessment of risks
resulting from the use of pulp-containing medical devices under FDA
jurisdiction is summarized in Chapter 9 of the Background Document to the
Integrated Risk Assessment. The major source document used in the
Background Document is the following:
USEPA. 1989. U.S. Environmental Protection Agency. Assessment of
exposures and risks to the general population from the use of
pulp-containing medical devices. Draft report. Washington, DC:
U.S. Environmental Protection Agency, Office of Toxic Substances.
Contract No. 68-02-4254.
2.9.2 Methodology
Medical devices believed to contain bleached wood pulp and the
parameters used to estimate exposure are presented in Table 13. The
industry average concentrations of 2,3,7,8-TCDD and 2,3,7,8-TCDF reported
for pulp in the 104-Mill Study (data obtained from EPA's Office of Water
Regulations and Standards in September 1989) were used to estimate dermal
exposures, except those exposures due to products made from rayon. These
concentrations were 8.5 pg/g for 2,3,7,8-TCDD and 84.4 pg/g for
2,3,7,8-TCDF. For the following specific devices, which are composed
primarily of dissolved cellulose, the average concentrations in pulp for
those mills producing dissolving cellulose were used; these concentra-
tions were 0.8 pg/g for 2,3,7,8-TCDD and 3.0 pg/g for 2,3,7,8-TCDF:
Unscented menstrual tampon;
Scented menstrual tampon;
Wound dressings containing carboxymethyl cellulose;
Medical absorbent fiber; and
Hydroxypropymethyl Cellulose.
Methods and assumptions used to estimate dermal exposure were patterned
after those used for assessing dermal exposures to consumer body contact
products (see Section 2.8).
2.9.3 Results and Discussion
Table 14 presents estimates of risks to the general population from
the use of pulp-containing medical devices. All predicted individual
risks are less than 10~9. Although population risks were not
calculated, they are assumed to be very low, less than 0.005 cancers per
year for any product.
The same assumptions regarding partitioning coefficients and
percutaneous absorption rates that were used to assess dermal exposures
to body contact papers in Section 2.8 were used here to assess dermal
exposures to 2,3,7,8-TCDD and 2,3,7,8-TCDF in medical devices. As with
46
1578q
-------
8941H-14
Table 13. Exposure/Risk Parameters for Medical Devices
Device name3
Unscented Menstrual Pad
Scented Menstrual Pad
Unscented Menstrual Tampon
Scented Mentrual Tampon
Alcohol Pads
Skin Prep. Wipe for
Dressing Wounds
Absorbable Hemostatic Agents
Wound Dressings Containing
Carboxymethyl Cellulose
Surgical Apparel: Hood, Cap,
Masks, Gowns, Foot Cov., Drapes
Adult Diapers
Medical Disposable Bedding
Medical Absorbent Fiber
Absorbent Tipped Applicator
Examination Gown
Ophthalmic Sponges
Hydroxypropymethyl Cellulose
Cottonoid Paddie
Electro Conductive Media
Cutaneous Electrode
Anesthetic Conduction Filter
Breathing Circuit Bacteria Filter
Heat & Moisture Condensers
Isolation Gowns
Contact type9
Skin
Skin
Intact Nat. Channel
Intact Nat. Channel
Skin
External, Short Term
Internal, Short Term
Compromised Tissue
%
External '
Skin
Skin
Skin
Skin
Skin
Surgical Aids
Intraocular Surg Aid
Compromised Tissue
Skin Surface! Intact)
Skin Surface! Intact)
No Direct Contact
No Direct Contact
No Direct Contact
External
Device
a
mass
(gm)
10
10
3-5
3-5
0.5-1
2
3-5
4
150 (OWNS)
7-10 (MSKS)
113.5
113.5
<0.5
0.25
113.5
0.5
<1 ml
2
1-5
1-5
2-3
2-3
2-3
150
Pulp in
product3
m
90
90
90
90
100
100
100
100
90
100
100
50
100
100
100
<1
<1
<1
100
100
100
100
Pulp
mass in
product3
(gm)
9
9
3.6
3.6
0.75
4
150
8.5
102.2
113.5
0.5
0.12
113.5
0.5
1
0.002
0.003
0.003
2.5
2.5
2.5
150
Exposure
duration3
(days/
lifetime)
2,400
2,400
2.400
2.400
6
NA
NA
NA
0.17
730
1
17.7
17.7
0.6
0.08
0.08
0.5
2
2
0.17
Volume of
liquid on
skin/
total
volume
(X)
25
25
100
100
100
50
100
50
NA
0.017
NA
50
100
NA
100
100
100
100
100
NA
Absorbtion
rate
Wetting through
factor
(X)
10
10
100
100
100
10
100
50
NA
10
NA
100
100
NA
100
100
100
100
100
NA
skinc
(%)
25
25
100
100
25
25
100
100
0.30
25
0.30
25
25
0.30
100
100
100
25
25
0.30
Partition Q
coefficient
TCDD
14,300
14,300
14.300
14,300
2.000
14,300
14,300
14,300
NA
14,300
NA
14,300
2.000
NA
14,300
14,300
2.000
2.000
2,000
NA
TCDF
5,300
5,300
5.300
5.300
2,000
5,300
5,300
5.300
NA
6.300
NA
5.300
2.000
NA
5,300
5,300
2.000
2,000
2,000
NA
NA - Not applicable
3 Data obtained from FDA/CDRH (Stratmeyer (1989) or telephone conversations between Versar and FDA).
Assumptions by Versar and FDA based on best available data and expected use patterns.
0 Based on data obtained from Babich (1989) and Babich et al. (1989) (Section 2.8 of this technical sunmary).
-------
3941H-15
Table 14. Estimates of Cancer Risks to the General Population from the Use of Pulp-Containing Medical Devices
Lifetime average
da i ly dose
(LAOD)a
(oa/kq/dav)
Device name
Unscented Menstrual Pad
Scented Menstrual Pad
Unscented Menstrual Tampon
Scented Menstrual Tampon
Alcohol Pad
Skin Prep. Wipe for Dressing
Wounds
Absorbable Hemostatic Agent
Wound Dressing Containing
Carboxymethyl Cellulose
Surgical Apparel: Hood, Cap,
Mask , Gown , Foot cov . , Drape
Adult Diaper
Medical Disposable Bedding
Medical Absorbent Fiber
Absorbent-Tipped Applicator
Examination Gown
Ophthalmic Sponge
Hydroxypropymethyl Cellulose
2,3.7,8-
TCDD
4.49E-08
4.49E-08
2.70E-07
2.70E-07
2.67E-09
2.08E-10
1.66E-08
7.82E-12
3.64E-07
1.05E-10
1.62E-06
3.46E-11
1.26E-09
9.71E-07
1.58E-11
2.50E-12
1
1
5
5
5
7
6
1
7
3
3
6
2
1
5
5
TEQ
.65E-07
.65E-07
.43E-07
.43E-07
.32E-09
.64E-10
.HE-OS
.57E-11
.25E-07
.43E-10
.23E-06
.96E-11
.51E-09
.94E-07
.15E-11
.03E-12
2,
EPA
4.68E-11
4.68E-11
. 1.54E-10
1.54E-10
1.51E-12
2.17E-13
1.73E-11
4.46E-15
2.06E-10
9.73E-14
9.15E-10
1.97E-14
7.13E-13
5.49E-10
1.46E-14
1.43E-15
,3,7,8-
TCDD
(%)
27
27
50
50
50
27
27
50
50
31
50
50
50
50
31
50
Lifetime individual
b,c
cancer risk
2,3,7,8-
FDA
5.25E-12
5.25E-12
1.73E-11
1.73E-11
1.70E-13
2.43E-14
1.95E-12
5.01E-16
2.31E-11
1.09E-14
1.03E-10
2.22E-15
8.00E-14
6.16E-11
1.64E-15
1.60E-16
TCDD
(%)
27
27
50
50
50
27
27
50
50
31
50
50
50
50
31
50
CPSC
4.01E-12
4.01E-12
2.41E-11
2.41E-11
2.39E-13
1.86E-14
1.48E-12
6.99E-16
3.25E-11
9.41E-15
1.45E-10
3.09E-15
1.13E-13
8.67E-11
1.42E-15
2.24E-16
,d
2,3,7,8-
TCDD
Potentially
exposed
(%) population
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
3.96E+07
3.71E+07
2.83E+07
5.20E+06
l.OE+06 -
Millions
Mi 1 lions
Hundreds
Mi llions
Thousands
l.OE+06 -
l.OE+06 -
l.OE+06 -
l.OE+06 -
l.OE+06 -
t.OE+07
of Thousands
(patients)
(health care)
l.OE+07
l.OE+07
l.OE+07
l.OE+07
l.OE+07
1.5 Mill ion Cataract
Oper./Year
Cottonoid Paddie
Electro-Conductive Media
Cutaneous Electrode
Anesthetic Conduction Filter6
Breathing Circuit Bacteria Fltr.e
Heat and Moisture Condensers6
Isolation Gown
2.38E-12
3.56E-12
3.56E-12
t
3.64E-07
4
7
7
7
.74E-12
.10E-12
.10E-12
.25E-07
1.34E-15
2.01E-15
2.01E-15
2.06E-10
50
50
50
50
1.51E-16
2.26E-16
2.26E-16
2.31E-11
50
50
50
50
2.12E-16
3.18E-16
3.18E-16
3.25E-11
100
100
100
100
Mi 1 lions
Millions
Mi llions
Mi llions
Mi 1 lions
Mi llions
Mi llions
Thousands
(patients)
(health care)
-------
8941H-16
Table 14. (continued)
a LADDs were calculated as follows:
[no] f g 1
(Concentration ^~\ x Pulp Mass ! [ x Exposure Duration (Days) x Volume of Liquid on Skin/Total Volume x Wetting Factor (unitless)
19 J
x I/Partition Coefficient (unitless) x Absorption Rate (%))
Body Weight (Kg) x Lifetime (70 years) x 365 days/year
There were two exceptions, however. The first exception was the method to estimate LAOD for surgical apparel, medical disposable bedding, examination
gowns, and isolation gowns. The other exception was for products where FDA already estimated the total mass of the product available for exposure (skin
prep, wipe for dressing wounds, absorbable hemostatic agents, and wound dressings containing carboxymethyl cellulose). In this case, LADD was estimated
as follows:
(Concentration x Total Mass Exposed x Volume of Liquid on Skin/Total Volume x Wetting Factor x I/Partition Coefficient x Absorption Rate)
Body Weight x 70 years x 365 days/year
The slope factors for 2,3,7.8-TCDD are as follows: EPA = 1.6xlO"4 (pg/kg day)"1; FDA = l.SxlO"5 (pg/kg day)"1; CPSC = 6.7xlO"5 (pg/kg/day)"1 .
c The slope factors for 2,3,7,8-TCOF are as follows: EPA = 1.6xlO"5 (pg/kg day)"1; FDA = l.SxlO"6 (pg/kg day)"1; CPSC =0. :
For EPA and FDA cancer slope factors, risk was estimated as follows: Risk = potency factor (pg/kg-day) x LADD (pg/kg-day)/0.55. However, for the
CPSC cancer slope factor, risk was estimated as follows: Risk = potency factor (pg/kg-day) x LADD (pg/kg-day) / 0.75. The divisor is changed to
0.75 (from 0.55) because a different bioassay was used. The total risk is the sum of the risks from TCDD and TCDF.
e There will be no direct contact for these products. The only potential exposure route is through inhalation of dioxin that leaves the filter or
condenser and enters the indoor air. Exposure through this pathway is expected to be negligible because only a very small amount of dioxin will leave
these products and enter the air, and of the amount that does enter indoor air, very little will actually enter the lungs and be absorbed.
-------
that assessment, this assessment required many other assumptions to
compensate for lack of firm data characterizing product composition and
the duration and frequency of product use. In general, conservative
assumptions were made when reliable information was not available.
However, even with the use of conservative assumptions, the predicted
cancer risks are negligible (all less than 10"9). Even though
population risks were not estimated in the assessment, the results in
Table 13 indicate that less than one excess cancer case per year would be
expected from all products combined.
2.1.0 -Summary of Risks from Inqestlon of Foods Contacting or Packaged
in Bleached Paper Products
2.10.1 Introduction
This risk assessment is discussed in more detail in Chapter 10 of the
Background Document to the Integrated Risk Assessment. The primary
source document used for this chapter in the Background Document is the
following:
USFDA. 1990. U.S. Food and Drug Administration. Carcinogenic risk
assessment for dioxins and furans in foods contacting bleached paper
products. Report of the Quantitative Risk Assessment Committee.
Washington, DC: U.S. Food and Drug Administration.
This assessment examined risks to (1) individuals in the U.S. population
consuming, average amounts of all foods that may have contacted bleached
paper products (i.e., mean consumers - total sample basis) and (2)
individuals who have been identified as "eaters" of various individual
foods at mean and 90th percentile intake levels that contact specific
bleached paper products (i.e., eaters only - food-by-food basis).
2.10.2 Methodology
Tables 15 and 16 list the bleached paper products and the associated
foods for which exposures and risks were estimated for the "mean
consumers - total sample basis" and "eaters only - food-by-food basis",
respectively. Tables 15 and 16 also present the values used for two
major parameters needed to estimate exposure: 2,3,7,8-TCDD TEQs in food
and individual food intake rates. Data on TEQ levels in paper are also
presented in Table 15. Concentrations of 2,3,7,8-TCDD TEQs assumed for
the paper products were based on one of three data sets:
(1) Concentrations in milk, cream, and juice cartons were based on
analytical data provided by the paper industry for the five
manufacturers of all paperboard used for these cartons.
50
lS78q
-------
8941H-51
Table 15. Carcinogenic Risk for Consumers Resulting from Total Dioxin TEQ Intake
from All Foods Contacting Bleached Paper ("mean consumer - total sample basis")
Food9
(paper article)
1.
2.
3.
4.
5.
6.
7.
8.
Milk (cartons)
Coffee (filters)
Cream (cartons)
Juice (cartons)
Coffee (cups)
Soup (cups)
Meals-seasoned meat.
(dual -oven trays)
Meals-seasoned meat
Paper TEQb
levels
(ppt)
2
8.8
2
2
10.1
10.1
vegs.
10.6
7.9
TEQ levels
in food
(ppq)
5
3.2
5
15
0.8
23
35
140
Food intake
per eating
event (g)
191
332
23.8
190
332
292
215
340C
Avg . da i ly
food intake
per person
(grams/day)
124
136
1.4
36
136
56
61
37
Daily
TEQ intake
per person
(pg/day)
0.62
0.44
0.007
0.54
0.11
1.3
2.1
5.2
(paper plates)
9. Popcorn (microwave bags) 5.9
10. Donuts, sweet rolls
(bakery cartons)
11. Frozen dairy desserts
13.8
45
50
67.8
1.6
7.7
0.072
0.39
(ice cream cartons) 13.8
12. Tea (bags) 17
13. Margarine (wrap) 17
50 110 23
8 301 22
82 10.8 7.3
Upper bound
Lower bound
Best estimate
1.2
0.12
0.60
12.7
5.5
9.1**
**The corresponding upper bound lifetime risks were estimated to be 2.4x10 based on FOA's
slope factor. 2.1xlO~5 based on EPA's slope factor, and 6.7xlO~6 based on CPSC's slope
factor.
aFood intake reported by Market Research Corporation of America (MRCA) obtained by multiplying the MRCA
mean frequency of eating occasions (1982-87 5-year Menu Census) by the mean grams/eating occasions from
USOA/NFCS, 1977-78 (Pao et al. 1982). Data are for the 2+ years age group, males and females, total sample
population.
104-mill average for producers (except updated for milk, cream, and juice carton producers) (API 1990).
The value for items 10-13 is the total 104-Mill Study average for bleached wood pulp.
cFood intakes based on NCASI production of 20 billion plates/yr and assumptions of 80 plates/person/year,
2 plates per eating occasion, and 340 g food per eating occasion.
dNCASI per capita consumption estimate based on 1.4 billion bags sold 1n the U.S. in 1989. No survey
data available for microwaveable popcorn.
eEst1mate based on Industry production figures for paper products.
Mldrange of lower and upper bound estimates.
51
-------
8941H-45
Table 16. Upper Bound Carcinogenic Risk for Consumers of Foods Contacting
Bleached Paper Contaminated with Dioxin ("eaters only - food-by-food basis")
Food8'6
(paper article)
Milk (cartons)
Coffee (filters)
Cream (cartons)
Juice (cartons)
Coffee (cups)
en Soup (cups)
PO
Meals-seasoned meat, vegs.
(dual -oven trays)
Meals-seasoned meat
(paper plates)
Popcorn (microwave bags)
TEQ levels
in food
(ppq)
5
3.2
5
15
0.8
23
35
140
45
Food intake0
(g/P/d)
mean/90th %tile
170/408
278/641
7.3/18.7
72/179
278/641
74/148
64/108
37/74f
16/329
d,
Uooer bound lifetime risk
FDA
2.2 x
2.4 x
1.0 x
2.9 x
5.9 x
4.5 x
5.9 x
1.4 x
1.9 x
ID'7
ID'7
io-8
io-7
io-8
ID'7
ID'7
io-6
io-7
Mean intake
EPA
2.0 x 10'6
2.1 x 10~6
8.9 x 10'8
2.6 x 10'6
5.2 x 10'7
4.0 x 10'6
5.2 x IO"6
1.2 x 10'5
1.7 x 10'6
CPSC
6.2 x
6.7 x
2.8 x
8.1 x
1.6 x
1.3 x
1.6 x
3.9 x
5.3 x
ID'7
ID'7
ID"8
ID'7
ID'7
ID'6
ID'6
ID"6
ID'7
90th
FDA
5.5
5.3
2.6
6.0
1.4
9.1
9.9
2.7
3.7
x 10"7
xlO'7
x 10"8
x 10"7
x 10"7
x 10"7
x 10'7
x 10'6
x 10'7
,e
oercentile intake
EPA
4.9 x
4.7 x
2.3 x
5.3 x
1.2 x
8.1 x
8.8 x
2.4 x
3.3 x
ID'6
ID'6
ID'7
ID'6
ID'6
ID'6
ID'6
ID'5
ID'6
CPSC
1.5 x
1.5 x
7.3 x
1.7 x
3.9 x
2.5 x
2.8 x
7.5 x
1.0 x
ID'6
ID'6
ID'8
ID'6
ID'7
ID'6
ID'6
ID"6
ID'6
Donuts, sweet rolls
(bakery cartons)
50
15/29
2.1 x 10"7 1.9 x 10'6 5.9 x 10"7 4.0 x 10"7 3.6 x 10~6 1.1 x 10"6
Frozen dairy desserts
(ice cream cartons)
50
32/63
4.3 x 10'7 3.8 x 10'6 1.2 x 10'6
8.5 x 10"7 7.6 x 10"6 2.4 x 10"6
-------
8941H-39
Table 16. (continued)
en
CO
Fooda'b
(paper article)
Tea (bags)
Margarine (wrap)
TEQ levels
In food
(ppq)
8
82
- d.e
Food intake Uooer bound lifetime risk
(a/p/d) Mean intake
mean/90th %tile FDA EPA CPSC
120/284 2.6 x 10"7 2.3 x 10"6 7.3 x 10"7
9/19 2.0 x 10"7 1.8 x 10"6 5.6 x 10"7
90th percent ile intake
FOA EPA ' CPSC
6.1 x 10"7 5.4 x 10'6 1.7 x 10"6
4.3 x 10~7 3.8 x 10"6 1.2 x 10"6
8Food intake obtained by multiplying the MRCA mean and 90th percentile frequencies of eating occasions (14-day average. 1982-87 5-year Menu Census) (MRCA
1988) by the mean grams/eating occasion from USDA/NFCS. 1977-78 (Pao et al. 1982). Data are for the 2+ years age group, males and females, eaters-only
population.
See Table 15, footnote for TEQ levels in the paper article.
cMean/90th percentile values.
Assumes a typical body weight of 60 kg for an adult.
eEPA classifies 2.3.7.8-TCDD as a "B2" carcinogen.
See Table 15, footnote c. Because of the conservatism of the per capita estimate, FDA selected 37 g/p/d to represent the mean food intake eaters-only
value as well. The 90th percentile value was assumed to be 2 times the mean. This is reasonably consistent with the relationship between the mean and
90th percentile figures for the other entries in the table.
9NCASI estimated per capita consumption of 1.6 g/person/day based on 1.4 billion bags sold in the U.S. in 1989. To obtain the eaters-only mean Intake, FDA
assumed that all microwaveable popcorn is consumed by only 10X of the U.S. population. The 90th percentile value was assumed to be 2 times the mean.
-------
(2) Concentrations in coffee filters, cup stock, dual-ovenable
trays, paper plates, bakery cartons, ice cream cartons, and
microwave popcorn bags were based on the average of the 104-Mill
Study.results for those pulp mills known to produce pulp for
these specific products.
(3) Concentrations in tea bags and margarine wraps were based on the
average TEQ concentrations for all pulps analyzed in the
104-Mill Study.
For the "mean consumer - total sample basis" assessment, food intake
rates for individual foods were calculated by multiplying the mean
frequency of eating occasions by the mean intake rate per eating occasion
for the total sample population based on the Market Research Corporation
of America's (MRCA) 1982-87 5-Year Menu Census. The "mean consumer -
total sample basis" food intake rates include data for all individuals
sampled and, therefore, consider individuals that do not eat the food
item of concern as well as those individuals that do. Consequently, the
mean food intake rates for the "mean consumer - total sample basis" are
somewhat lower than those for the "eaters only - food-by-food basis."
For the "eaters only - food-by-food basis" assessment, food intake rates
for individual foods were calculated by multiplying the MRCA mean and
90th percentile frequency of eating occasions by the mean intake rate per
eating occasion for "eaters only" reported in the USDA's 1977-78 National
Food Consumption Survey.
The paper industry conducted a series of migration tests on paper
food-contact products identified by FDA as high-priority products. These
studies were performed under conditions intended to closely simulate
actual food-contact applications. The results of these tests form the
basis for FDA's estimates of rates of dioxin migration from paper into
food. Migration studies were performed on coffee filters, milk cartons,
cream cartons, orange juice cartons, cup stock and paper stock for hot
foods, dual-ovenable trays, and microwave popcorn bags. For those paper
product/food combinations not tested (i.e., bakery cartons, frozen dairy
cartons, tea bags, and margarine wraps), migration rates developed for a
similar type of paper product were used as surrogate values.
2.10.3 Results and Discussion
Table 15 presents the results of the cancer risk assessment for the
"mean consumer - total sample basis." The estimates of lifetime upper
bound individual lifetime cancer risk range from 2.4 x 10"6 (using
FDA's cancer slope factor) to 2.1 x 10"5 (using EPA's cancer slope
factor).
Table 16 presents the results of the cancer risk assessment for the
"eaters only - food-by-food basis." The maximum estimated risks for mean
consumers (eaters only) of any of the food products is less than 1.4 x
54
1578q
-------
10~6 using FDA's cancer slope factor and less than 1.2 x 10~5
using EPA's cancer slope factor. The risks for 90th percentile
(eaters-only) consumers of individual foods are approximately two times
greater than risks for the mean (eaters-only) consumer.
FDA used an ADI of 1-10 pg/kg/day to assess non-cancer risks of
potential exposures. This is the most sensitive non-cancer toxicological
endpoint associated with dioxin exposure in animal studies. Although the
estimated daily exposures in units of pg/kg/body weight/day are not shown
in Tables 15 and 16, the calculated exposures were all less than the ADI.
The major uncertainties inherent in this assessment concern
assumptions regarding food intake rates and dioxin migration rates. The
estimation of exposure to TCDD and TCDF from consumption of all foods
contacting paper articles requires consideration of appropriate food
intake information. Available nationally representative food consumption
data bases, however, do not provide information on whether foods are
sold, held, heated, cooked, or served in contact with different types of
materials. Therefore, for estimating the total dioxin TEQ intake from
all foods that may contact bleached paper, available food consumption
data for average consumers of each of the foods were used in conjunction
with the assumption that all such foods have indeed been in contact with
bleached paper prior to being consumed. This necessary assumption leads
to an overestimate of consumption of food that has been in contact with
paper and, hence, to an overestimate of total dioxin TEQ exposure.
This upper bound estimate of total dioxin TEQ exposure (12.7 pg/p/day)
was adjusted through a comparison with a lower bound estimate of dioxin
TEQ exposure, specifically, a per capita exposure obtained using
industry-provided production figures and estimates of the amount of-food
that might contact the paper. Recognizing that a reasonable estimate
should fall between the upper and lower bound estimates, FDA derived a
"best estimate" of mean total dioxin TEQ exposure of 9.1 pg/person/day.
This value is the mid-point between the upper and lower bound estimates.
For the "eaters only - food-by-food basis" assessment, it was also
assumed that all foods consumed have indeed been in contact with bleached
paper prior to being consumed. The other assumptions used for the total
population exposure analysis also apply to the "eaters-only" analysis.
Therefore, the dioxin TEQ intakes in Table 16 may also be considered as
upper bound estimates of mean and 90th percentile for "eaters" of each of
the foods. The dioxin TEQ exposures in Table 16 must not be summed
because the population of eaters is not the same for each food category.
All of the migration studies demonstrated detectable levels of
transfer of the dioxin congeners to the test foods. The temperature of
foods, their composition, the nature of the paper article, and the dioxin
congener levels in the paper articles were all found to influence the
55
1578q
-------
extent of transfer to test foods. Recent production lots of paper and
paperboard used in food applications have been shown to have
significantly lower levels of dioxin congeners than the levels used for
this assessment. Therefore, the risks from these articles should be
expected to be lower. 'However, FDA has not used these recently submitted
figures to try to estimate lower risks because the quality and the
completeness of these reports have not been assessed and migration
studies that might show the extent of reduced exposure (and risk) have
not been conducted.
Even considering these uncertainties, the results of the assessment
of individual lifetime cancer risks indicate a potentially significant
risk is posed by "current" (i.e., as used in this assessment) levels of
dioxin in paper food contact product. Although individual risks are not
high, the potentially exposed population is much larger than any other
exposed population group addressed in the Integrated Assessment.
2.11 Summary of Risks from Use of Food. Drug, and Cosmetic Products
Containing Cellulose Derivatives
2.11.1 Introduction
This section summarizes human exposures and risks estimated from use
of food, drug, and cosmetic products containing cellulose derivatives.
The assessment of risks resulting from use of food, drug, and cosmetic
products containing cellulose derivatives is discussed in greater detail
in Chapter 11 of the Background Document to the Integrated Risk
Assessment. Exposure pathways examined were dermal exposures to cosmetic
products and ingestion of food additives and drugs. Products analyzed
included cosmetic products; all foods, including high-fiber breads; and
drugs such as tablet binders and laxatives. The major source documents
for this chapter in the Background Document are the following:
USFDA. 1990. U.S. Food and Drug Administration. Carcinogenic risk
assessment for dioxins and furans in cosmetic products containing
cellulose derivatives produced from bleached wood pulp. Report of
the Quantitative Risk Assessment Committee. Washington, DC: U.S.
Food and Drug Administration.
USFDA. 1990. U.S. Food and Drug Administration. Carcinogenic risk
assessment for dioxins and furans in cellulose derivatives used in
foods and ingested drug products. Report of the Quantitative Risk
Assessment Committee. Washington, DC: U:S. Food arid Drug
Administration.
56
1578q
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2.11.2 Methodology
(1) Cosmetic products. Powdered cellulose and various cellulose
ethers are used in a wide range of leave-on type cosmetic products (e.g.,
lotions, creams, and powders) and wash-off type products (e.g., shampoos,
conditioners, and dentifrices). The leave-on products are reported to
contain less than 2 percent cellulose derivatives, while the wash-off
products are reported to contain less than 1 percent. It was assumed
that all cosmetic products are likely to contain the derivatives, and it
was assumed that the derivatives are present at the maximum levels
discussed above.
To account for the high amount of cosmetics used by some individuals,
90th percentile daily use rates for various products were derived by
combining information on the average amount of cosmetic product used per
application with 90th percentile frequency of use data. Standard factors
used by FDA to account for the extent to which wiping, wearing off, or
washing remove the products from the skin were combined with the usage
data to identify those products that present the greatest potential for
dioxin exposure. Three generic products (dentifrices, body lotions, and
hair shampoos) were identified that dominate the potential for exposure.
The data available on 2,3,7,8-TCDD/TCDF concentrations in pulp from
which cellulose-derived products are prepared indicate nondetectable
levels. For this assessment, it was assumed that the cellulose
derivatives contain 0.3 ppt of dioxin TEQ. This value represents
approximately one-half the detection limit of the method used for
analysis of dioxins in pulp.
As discussed in Sections 2.8 and 2.9, evaluation of the limited data
available on percutaneous absorption of 2,3,7,8-TCDD indicates that an
assumption of 25 percent absorption over a 24-hour period is not
unreasonable. Therefore, this value was used in the assessment.
(2) Cosmetic wet wipes. Cosmetic wet wipes used to wipe hands and
used in diaper changes are manufactured using either synthetic fibers or
bleached pulp. Industry-supplied data indicate that wipes dispensed from
pop-up containers do not contain any pulp; however, those that are
dispensed from tubs in which the wipes lie flat in a stack are composed
of bleached pulp (75 to 85 percent of dry weight) with the remaining
material being binders and synthetic fibers. Potential exposure to
dioxin congeners in the wet wipes made from bleached pulp can occur as a
result of migration from the web into the lotion during extended storage,
transfer of the lotion to the skin during wet wipe usage, and dermal
uptake during the time between wet wipe usage and subsequent washing of
the skin.
57
1578q
-------
The following assumptions were used to estimate exposures:
The dioxin TEQ in wet wipes was assumed to be 17 ppt, based on
the average pulp level in 104-Mill Study;
The dioxin TEQ/wet wipe lotion partition coefficient was
assumed to be 300, based on empirical data from ongoing industry
studies;
The percent of lotion transferred from wipes to skin equals 20
percent for infants and 2 percent for adults;
25 percent of the dioxin TEQ is absorbed by the skin;
8 wet wipes are used daily.
(3) Food additives and drugs. Cellulose and cellulose-derived
esters and ethers are used in food and drug formulations to produce
certain effects such as anticaking, thickening, and stabilizing. Foods
such as baked goods (e.g., bread, cookies, rolls, pie fillings, icings),
dairy products (e.g., ice cream, whipped toppings, milkshakes), pasta,
sausage casings, diet beverages, candy, dried fruits, and flavorings are
foods identified by the paper industry that may contain powdered
cellulose. Cellulose derivatives are also widely used in the formulation
of drug tablets, suspensions, and creams.
The following assumptions and data were used to estimate the upper
bound carcinogenic risk of exposure to dioxins and furans by ingestion of
food and drugs containing cellulose and cellulose derivatives:
As previously stated, the data available on 2,3,7,8-TCDD/TCDF
concentrations in pulp from which cellulose-derived products are
prepared indicate nondetectable levels. Dioxin and related furan
were assumed to be present in pulps at one-half the average
detection limit (i.e., about 0.3 ppt), based on the 104-Mill
Study.
It was assumed that the chemical and mechanical processing
steps used to prepare the cellulose derivatives do not increase
the residual levels of dioxins and furans above the levels
assumed to be present in the bleached wood pulp used to
manufacture these derivatives.
It was assumed that 100 percent of the U.S. population eat at
least one food containing a cellulose derivative.
58
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Estimates of food intake for the foods of interest were
obtained from a 5-year (1982-87) Menu Census data base that
contains 14 consecutive days of data and is likely to be
representative of a typical diet for all age groups (MRCA 1987).
The intake values for each food item were multiplied by the use
levels of the appropriate cellulose derivative to obtain the
intake estimate for the cellulose derivative. The intake
estimate for each cellulose derivative was multiplied by its
dioxin TEQ concentration to obtain the set of dioxin TEQ intakes
that could be summed to provide an upper bound total population
mean dioxin TEQ intake.
Daily ingestion of cellulose derivatives resulting from chronic
consumption of tablets was assumed to be less than 1 g/person/day
(based on FDA data).
The use of either methyl cellulose or sodium carboxymethyl
cellulose in laxatives can result in daily doses of either of
these derivatives as high as 6 g/person/day (Handbook of
Nonprescription Drugs, 7th ed., 1982).
2.11.3 Results and Discussion
Table 17 summarizes the estimated exposures and risks for the
cosmetic products, wet wipes, and food and drug additives.
As discussed in the methods section (Section 2.11.2), numerous
conservative but reasonable assumptions were used to estimate exposures
and risks. However, even with the use of conservative assumptions, the
predicted individual cancer risks are very low, particularly for the
cosmetic products containing cellulose derivatives and the cosmetic wet
wipes. However, the potentially exposed population could be quite large,
numbering in the millions. Also, although non-cancer risks were not
assessed in the source documents, comparison of the daily exposure
estimates in Table 17 with the estimated RFD of 1 pg/kg/day and the
estimated health advisories of 10 to 300 pg/kg/day that were developed by
EPA for this assessment indicates that the exposures pose minimal risk of
non-cancer effects.
2.12 Summary of Risks to Wildlife from Land Application of Pulp and
Paper Hill Sludge and to Aquatic Life from Discharge of Effluents
2.12.1 Introduction
This section summarizes risks to wildlife from land application of
sludge and to aquatic life from discharge of effluents containing
2,3,7,8-TCDD and 2,3,7,8-TCDF. The assessment of these risks is
described in greater detail in Chapter 13 of the Background Document to
59
1578q
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8941H-24
Table 17. Upper Bound Carcinogenic Risk for Users of Food, Drug, and Cosmetic Products Containing
Cellulose Derivatives
Lifetime average Upper bound lifetime risk0
dioxin TEQ exposure
User (pg/kg/day) FDA EPA CPSC
Cosmetic Products
Dentifrice user 8 x l(f6 1.3 x 10"10 1.2 x l(f9
Lotion user 8 x 10"5 2.4 x 10"9 2.1 x 10"8
Shampoo user 1.6 x 10"6 4.7 x 10"11 4.2 x 10"10
Cosmetic Wet Wipes
Wet wipe (adult) 1.8 x 10~5 (2.2 x 10"4)a 5.8 x Hf 10 5.2 x 10"9
Wet wipe (infant) 5.6 x 10~4 (1.3 x 10"2)a 1.6 x l(f8 1.4 x 10"7
Food and Drugs
All foods 2.3 x 10~2 4 x 10~7 3.6 x 10"6
High-fiber bread 1.5 x 10"2 2 x 10~7 1.8xlO"6
(2.7xlO~2)b (4xlO"7)b (3.6xlO~6)b
Tablet binders 5 x 10~3 8 x Iff8 7.1 x 10"7
Laxatives 3 x 1
-------
the Integrated Risk Assessment. The major source documents for this
chapter in the Background Document are the following:
NYDEC. 1987. New York Department of Environmental Conservation.
Niagara River biota contamination project: fish flesh criteria for
piscivorous wildlife. Technical Report 87-3. Division of Fish and
Wildlife, Bureau of Environmental Protection.
Rabert WS. 1990. An update on the environmental effects of TCDD and
TCDF releases from pulp and paper mills on aquatic and terrestrial
animals. U.S. Environmental Protection Agency, Office of Toxic
Substances, Health and Environmental Review Division. Memorandum to
P. Jennings, EPA, Exposure Assessment Branch. June 26, 1990.
USEPA. 1990a. U.S. Environmental Protection Agency. Risk
assessment for 2,3,7,8-TCDD and 2,3,7,8-TCDF contaminated receiving
waters from U.S. chlorine-bleaching pulp and paper mills.
Washington, DC: Office of Water Regulations and Standards, U.S.
Environmental Protection Agency. August 1990.
USEPA. 1990b. U.S. Environmental Protection Agency. Assessment of
risks from exposure of humans, terrestrial and avian wildlife, and
aquatic life to dioxins and furans from disposal and use of sludge
from bleached kraft and sulfite pulp and paper mills. Washington,
DC: Office of Toxic Substances and Office of Solid Waste.
EPA 560/5-90-13.
2.12.2 Methodology
(1) Methodology for assessment of risks to wildlife. Exposure of
wildlife to dioxins and furans occurs as a result of ingestion of prey
items that have bioconcentrated 2,3,7,8-TCDD and 2,3,7,8-TCDF and also as
a result of direct ingestion of soil to which pulp and paper mill sludge
has been land-applied. Species selected for evaluation were obtained
from lists maintained by Natural Heritage Programs in the seven states
where land application of pulp and paper mill sludge currently occurs.
These species represent common species as well as some threatened and
endangered species believed to inhabit regions of the state where land
application is practiced.
Soil concentrations of 2,3,7,8-TCDD and 2,3,7,8-TCDF were modeled for
sludge-amended soil in each of the seven states where pulp and paper mill
sludge is land-applied. The modeled concentrations were the average
concentrations over a 1-year period after sludge is applied to soil.
Wildlife exposures were then estimated for three ingestion and uptake
levels: "low," "best," and "high" estimates. These three estimates were
based on several variables including: uptake rates for vegetation eaten
61
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by wildlife; bioconcentration factors (BCF) for earthworms, insects, and
small mammals; BCF for fish from sediment; whole-body elimination rate
from birds, small mammals, and large mammals; percent of dioxin absorbed
from food; total food consumption for birds and mammals; percent of diet
that is soil; and fraction of food sources from sludge-applied land. The
risk assessment was performed by computing the resultant exposure levels
for each type of animal for each state and for each scenario (low, best,
and high), and then comparing these exposure estimates with the NOAELs or
LOAELs for the same or similar species. The following values for NOAEL
and LOAEL were determined and compared with estimated exposures:
2,3,7,8- 2,3,7,8-
TCDD (ppt) TCDF (pot)
LOAEL for bird eggs 65 650
NOAEL for migratory birds 11 110
NOAEL for nonmigratory birds 6 60
LOAEL for small mammals 10 100
LOAEL for large mammals 1.7 17
For estimated exposures, it was assumed that each species examined,
with the exception of the river otter, obtained all of its food from the
land application area. Because of their large range, river otters are
assumed to obtain less than 10 percent of their diet from land
application sites abutting waterways. Risks to raptors, such as owls
feeding on mice or other small wildlife in treated areas, and risks to
piscivorous birds, such as the bald eagle and osprey, were not addressed
in this assessment because their home ranges were determined to be
considerably larger than the land application areas. If, in the future,
the concentrations of 2,3,7,8-TCDD/TCDF in sludge in the sizes of the
application areas increased, then the risks to these and other wildlife
species would need to be reevaluated.
(2) Methodology for assessment of risks to aquatic life from
effluents. Currently, sufficient data are not available concerning the
chronic effects of 2,3,7,8-TCDD and 2,3,7,8-TCDF on aquatic life to
derive national water quality or sediment criteria for these
contaminants. However, several studies have been conducted that provide
some information concerning the long-term effects of 2,3,7,8-TCDD and
2,3,7,8-TCDF on aquatic life from subacute exposures. Sub-acute studies
involve much longer exposure durations than acute studies but are not
full-life-cycle exposures assessed in chronic studies. These studies
were used to develop estimated chronic toxicity values for 2,3,7,8-TCDD
and 2,3,7,8-TCDF. Potential aquatic life impacts were determined by
comparing estimated in-stream concentrations of 2,3,7,8-TCDD and
2,3,7,8-TCDF to these estimated chronic toxicity values: 0.038 pg/1 for
2,3,7,8-TCDD and 0.41 pg/1 for 2,3,7,8-TCDF. Site-specific water column
contaminant concentrations were calculated by USEPA (1990a) using the
62
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simple dilution exposure assessment approach and low (7Q10) receiving
stream flow conditions.
The effects on birds and mammals resulting from ingestion of
contaminated fish were also considered. The measured levels of dioxins
in fish downstream from the 104 mills were compared with maximum dietary
levels of dioxins and furans recommended for birds and mammals by the New
York Department of Environmental Conservation (NYDEC 1987).
2.12.3 Results and Discussion
(1) Assessment of risks to wildlife. Tables 18 and 19 summarize
the estimated risks to mammals and to birds and bird eggs, respectively,
from exposure to 2,3,7,8-TCDD as a result of land application of sludge.
For the states with the lowest estimated exposures, adverse effects were
predicted to be low for most of the species examined. For the states
with the highest estimated exposures, adverse effects were predicted to
be high for some of the species examined; for example, the shrew, bat,
mole, robin, and woodcock. These species at greatest risk are those
species whose diets consist of a high proportion of prey that
bioconcentrate dioxins (e.g., earthworms and insects). Of those species
examined, the avian species at greatest risk is the American woodcock;
the mammalian species at greatest risk is the least shrew. For both
birds and mammals, the risk levels-appear to be highest for exposures to
animals in Georgia. Adverse effects on individuals may be important if
the individuals are members of species that are endangered or
threatened. Table 20 presents results of a preliminary search for
endangered and threatened species in seven counties where the eight pulp
and paper mills that apply pulp and paper mill sludge to land are located.
However, no direct evidence was found to indicate exposure of endangered
or threatened species to dioxins from pulp and paper mills.
As a check on the methodology and results of this assessment, modeled
estimates of 2,3,7,8-TCDD and 2,3,7,8-TCDF in soil and 2,3,7,8-TCDD in
bird eggs were compared with measured concentrations collected as part of
field studies of the impact of pulp and paper mill sludge application to
a red pine plantation (NCASI 1987, Thiel et al. 1988). The comparison
indicated the modeled estimates for the Wisconsin site were very similar
to the measured concentrations at the Red Pine Plantation application
site in Wisconsin. The modeled soil concentrations (Table 18) and the
average measured soil concentrations (NCASI 1987) for 2,3,7,8-TCDD were 9
ppt and 10.8 ppt, respectively, and for 2,3,7,8-TCDF the values were
identical, 106 ppt. Thiel et al. (1988) also conducted studies at the
same Wisconsin sludge application site, but during the next year when
2,3,7,8-TCDD concentrations in the sludge were higher. Levels of
2,3,7,8-TCDD in bluebird and robin eggs were measured, and the reported
levels in bluebird eggs ranged from 6 to 11 ppt (Thiel et al. 1988). The
values predicted for the "best estimate" model (Table 19) were 27 ppt for
the bluebird, a factor of 4.5 to 2.5 higher than the measured data.
63
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8941H-43
Table 18. Estimates of Risks to Manna Is from Exposure to
2,3,7,6-TCOD as a Result of Land Application of Pulp
and Paper Mill Sludge
Species/state
Least Shrew
Georgia
Maine
Maryland
Mississippi
Ohio
Pennsylvania
Wisconsin
Grey Batb
Georgia
Maine
Maryland
Mississippi
Ohio
Pennsylvania
Wisconsin
Eastern Mole
Georgia
Maine
Maryland
Mississippi
Ohio
Pennsylvania
Wisconsin
Virginia Opossum
Georgia
Maine
Maryland
Mississippi
Ohio
Pennsylvania
Wisconsin
Striped Skunk
Georgia
Maine
Maryland
Mississippi
Ohio
Pennsylvania
Wisconsin
Sludge
cone.
(PPt)
220
13
80
681
145
34
109
220
13
80
681
145
34
109
220
13
80
681
145
34
109
220
13
80
681
145
34
109
220
13
80
681
145
34
109
Soil
cone.
(PPt)
181
1
80
14
145
0.2
9
181
1
80
14
145
0.2
9
181
1
80
14
145
0.2
9
181
1
80
14
145
0.2
9
181
1
80
14
145
0.2
9
Adult risks3
(times LOAEL)
Low Best High
2.99
0.02
1.32
0.24
2.39
0
0.15
3.62
0.02
1.60
0.29
2.90
0
0.18
1.22
0.01
0.54
0.10
0.98
0
0.06
0.72
0
0.32
0.06
0.58
0
0.04
0.38
0
0.17
0.03
0.31
0
0.02
44.80
0.25
19.80
3.54
35.89
0.06
2.23
18.10
0.10
8.00
1.43
14.50
0.02
0.90
15.40
0.09
6.81
1.22
12.34
0.02
0.77
2.88
0.02
1.27
0.23
2.31
0
0.14
1.92
0.01
0.85
0.15
1.54
0
0.10
114.48
0.63
50.60
9.04
91.71
0.14
5.69
27.15
0.15
12.00
2.15
21.75
0.03
1.35
38.50
0.21
17.02
3.04
30.85
0.05
1.91
4.69
0.03
2.07
0.37
3.76
0.01
0.23
2.89
0.02
1.28
0.23
2.32
0
0.14
64
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8941H-44
Table 18. (Continued)
Species/state
Sludge
cone.
(PPt)
Soil
cone.
(PPt)
Adult risks*
(times LOAEL)
Low Best
High
Nine-Banded Armadillo
Mississippi
681
14
0.11
0.31
0.37
River Otter
Georgia
Maine
Maryland
Mississippi
Ohio
Pennsylvania
Wisconsin
220
13
80,
681
145
34
109
181
1
80
14
145
0.2
9
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0.06
0
0.03
0
0.05
0
0
These factors represent the comparison factor between the estimated
exposure to mammals and the LOAEL for 2.3,7,8-TCDD of 10 ppt for small
mammals and the LOAEL of 1.7 ppt for large mammals. For example, the best
estimate of exposure of the Least Shrew to 2,3,7,8-TCDD from sludge
applied to land in Georgia is 44.8 times greater than the LOAEL for small
mammals (i.e., 10 ppt).
The Grey Bat is considered to be an endangered species in the State of
Georgia.
65
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8941H-45
Table 19. Estimates of Risks to Adult and Hatching Birds from Exposure to 2,3,7,8-TCDD as a Result of
Land Application of Pulp and Paper Mill Sludge
Sludge .
cone.
Species/state (ppt)
American Robin
Georgia
Maine
Maryland
Mississippi
Ohio
Pennsylvania
Wisconsin
Woodcock
Georgia
Maine
Maryland
Wisconsin
Eastern Bluebird
Maine
Maryland
Ohio
Pennsylvania
Wisconsin
Great Crested Flycatcher
Georgia
Maryland
Mississippi
Ohio
Pennsylvania
Loggerhead Shrike0
Maryland
Mississippi
Ohio
Pennsylvania
Eastern Meadow lark
Maryland
Mississippi
Ohio
Pennsylvania
220
13
80
681
145
34
109
220
13
80
109
13
80
145
34
109
220
80
681
145
34
80
681
145
34
80
681
145
34
Exposure
cone.
(ppt)
181
1
80
14
145
0.2
9
181
1
80
9
1
80
145
0.2
9
181
80
14
145
0.2
80
14
145
0.2
80
14
145
0.2
Adult risks3
(times NOAEL)
Low Best High
0.67
0
0.30
0.05
0.53
0
0.03
0.68
0
0.30
0.03
0
0.29
0.53
0
0.03
0.56
0.25
0.04
0.45
0
0.70
0.13
1.28
0
0.15
0.03
0.28
0
4.13
0.02
1.83
0.33
3.31
0.01
0.21
27.61
0.15
12.20
1.37
0.02
1.70
3.09
0
0.19
3.28
1.45
0.26
2.63
0
2.87
0.51
5.20
0.01
0.88
0.16
1.60
0
6.57
0.04
2.90
0.52
5.26
0.01
0.33
78.89
0.44
34.87
3.92
0.03
2.61
4.72
0.01
0.29
4.93
2.18
0.39
3.95
0.01
3.78
0.68
6.85
0.01
1.33
0.24
2.42
0
Embryo risks
(times LOAEL)
Low Best
1.36
0.01
0.60
0.11
1.09
0
0.07
1.36
0.01
0.60
0.07
0
0.27
0.49
0
0.03
1.36
0.38
0.07
0.68
0
0.90
0.16
1.63
0
0.29
0.05
0.53
0
10.59
0.06
4.68
0.84
8.49
0.01
0.53
62.37
0.34
27.57
3.10
0.05
3.72
6.75
0.01
0.42
6.24
2.76
0.49
5.00
0.01
3.97
0.71
7.20
0.01
2.11
0.38
3.82
0.01
High
30.16
0.17.
13.33
2.38
24.16
0.04
1.50
358.32
1.98
158.37
17.82
0.13
10.19
18.47
0.03
. 1.15
16.80
7.43
1.33
13.46
0.02
7.88
1.41
14.29
0.02
5.71
1.02
10.34
0.02
66
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8941H-46
Table 19. (Continued)
Species/state
Tree Swallow
Georgia
Maine
Maryland
Ohio
Wisconsin
Pine Warbler
Georgia
Maine
Maryland
Ohio
Wisconsin
Wood Thrush
Georgia
Maine
Maryland
Ohio
Wisconsin
Sludge
cone.
(PPt)
220
13
80
145
109
220
13
80
145
109
220
13
80
145
109
Exposure
cone.
(ppt)
181
1
80
145
9
181
1
60
145
9
181
1
80
145
9
Low
0.57
0
0.25
0.46
0.03
0.82
0
0.36
0.65
0.04
0.33
0
0.15
0.27
0.02
Adult risks3
(times NOAEL)
Best
3.34
0.02
1.47
2.67
0.17
4.76
0.03
2.10
3.81
0.24
1.94
0.01
0.86
1.55
0.10
High
5.05
0.03
2.23
4.05
0.25
7.15
0.04
3.16
5.73
0.36
2.98
0.02
1.32
2.39
0.15
Low
1.12
.0.01
0.49
0.89
0.06
0.92
0.01
0.41
0.74
0.05
0.55
0
0.24
0.44
0.03
Embryo risks
(times LOAEL)
Best
8.18
0.05
3.62
6.55
0.41
6.79
0.04
3.00
5.44
0.34
4.05
0.02
1.79
3.25
0.20
High
22.19
0.12
9.81 .
17.77 .
1.10
18.26
0.10
8.07
14.63
0.91
11.15
0.06
4.93
8.93
0.55
a These factors represent the comparison factor between the estimated exposure to birds and the NOAEL for
2,3,7,8-TCDD of 11 ppt for migratory birds and 6 ppt for nonmigratory birds.
These factors represent the comparison facator between the estimated exposure to bird eggs and the LOAEL for bird
eggs for 2,3.7,8-TCDD of 65 ppt.
c The Loggerhead Shrike is considered to be a threatened species in the State of Maryland.
67
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8941H-29
Table 20. Results of Preliminary Search for Endangered (E) and
Threatened (T) Species Found in the Counties Where Pulp
and Paper Hills Are Located that Apply Dioxin- and
Furan-Contaminated Pulp and Paper Mill Sludge to Land
Endangered and
threatened species
States with soil application
GA
ME
HD
MS
OH
PA
WI
Manna Is
Indiana bat (E)
West Indian Manatee (E)
Birds
Bald Eagle (E)
Piping Plover (E)
Wood Stork (E)
Red-Cockaded Woodpecker (E)
Reptiles
Eastern Indigo Snake CO
Gopher Tortoise (T)
Kemp's Ridley Sea Turtle (E)
Leatherback Sea Turtle (E)
Loggerhead Sea Turtle (T)
Fish
Shortnose Sturgeon
Invertebrates
Iowa Pleistocene Snail
(terrestrial) (E)
K
K
K
K
P
K
Plants
Harperalla (E)
Small Whorled Pogonia
(E)
8Based on information dated October 26, 1989.
bPulp mill sites:
Camden County, Georgia
Cumberland County, Maine
Allegheny County, Maryland
Perry County, Mississippi
Ross County, Ohio
Wyoming County, Pennsylvania
Wood County, Wisconsin
P - Possibly present in county
K - Known to be present In county
68
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Levels of 2,3,7,8-TCDD measured in robin eggs ranged from 120 to 162 ppt
(Thiel et al. 1988). The value predicted for the "best estimate"
scenario was 34 ppt (Table 19), a factor of 3.5 to 4.8 lower than the
measured data. Considering the wide range in biological variability in
natural systems, the wildlife risk assessment model compares well with
measured values, at least for 2,3,7,8-TCDD levels in bluebird and robin
eggs.
Based on the results of the assessment and the assumption that wild
species are at least as sensitive as the laboratory species on which the
adverse effects levels are based, EPA is confident that, on land with
high dioxin levels, adverse effects to wildlife are likely to occur. The
size of the exposed populations is believed to be small at some sites
because, at present, only limited land areas are being utilized for land
application of pulp and paper mill sludge. However, only the otter
consistently showed low risk estimates, and some wildlife species showed
high risk estimates in some states. For some of these common species
with large ubiquitous populations, the local impacts might be small, but
any effects on local wildlife populations are nevertheless an adverse
impact on the local ecosystem. Moreover, sufficient toxicity data are
not available for avian reproduction tests and the adult bird toxicity
endpoint is based on a LOAEL rather than a NOAEL. Consequently, it is
impossible to conclude from these risk estimates that any of these
exposure levels or scenarios are "safe" to wildlife.
(2) Assessment of risks to aquatic life. Water column
concentrations of 2,3,7,8-TCDD immediately downstream from at least 80
out of 90 mills evaluated (89 percent) were estimated to exceed the
lowest reported chronic effects level of 0.038 pg/1 for 2,3,7,8-TCDD.
The 2,3,7,8-TCDF concentrations in the water column below at least 74
mills (82 percent) exceeded the lowest reported chronic effects level of
0.41 pg/1 for 2,3,7,8-TCDF.
The 7Q10 is used as a design flow for stressed aquatic systems;
however, use of 7Q10 receiving water flow rates does not necessarily
result in the extreme worst-case scenario for aquatic life acute
impacts. 7Q10 is defined as the lowest consecutive 7-day average flow
over a 10-year period. Streamflows less than or equal to the 7Q10 flow
(expressed as a daily flow) can occur multiple times within a given year
(for periods of 1 day to several days). It is possible that even brief
exposures (i.e., less than 7 days) to high concentrations of 2,3,7,8-TCDD
and 2,3,7,8-TCDF can result in toxic effects to aquatic organisms, and
such effects may occur after an appreciable delay following only brief
exposures.
Upon comparing the measured levels of dioxins for fish collected
downstream from the 104 mills with the maximum daily dietary level of
dioxin (i.e., 3 ppt) recommended by the New York Department of
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Environmental Conservation (NYDEC 1987) for mammals and birds feeding on
fish, it was determined that 66 percent of the fish, based on samples
from the National Bioaccumulation Study (USEPA 1989), exceeded this NYDEC
recommended value. Over 38 percent of the fish sampled showed measured
levels which exceeded the NYDEC recommended value by twofold. EPA has
not evaluated the technical basis for the dietary levels of dioxin
recommended by NYDEC.
Taking into account the above assumptions, simplifications, and
limitations concerning the risks to aquatic life from effluent discharges
of 2,3,7,8-TCDD and 2,3,7,8-TCDF, the results of this assessment indicate
that the levels of 2,3,7,8-TCDD and 2,3,7,8-TCDF contamination in the
water column resulting from surface water effluent discharges from many
chlorine-bleaching pulp and paper mills could be exerting significant
adverse effects on aquatic life and on avian and mammalian predators
feeding upon aquatic life.
2.13 Summary of Toxlcltv. Environmental Releases, and Effluent
Concentrations of Other Chlorinated Organics
Risks from exposure to 2,3,7,8-TCDD and 2,3,7,8-TCDF are the primary
focus of the Integrated Assessment. Many other chlorinated organic
compounds (OCOs), however, are produced during pulp and paper mill
bleaching and processing operations.
A screening-level analysis of OCOs found in pulp and paper mill
effluent was performed. This analysis was intended to provide a
qualitative assessment of the types and amounts of OCOs present in pulp
mill effluents. Although much information on OCOs in pulp mill effluent
was available, no data were available on concentrations of OCOs in sludge
or pulp. Also, the information available is inadequate to permit the
assessment of risks to humans or wildlife. Based on the OCO data that
are available, some general observations can be made:
(1) Some OCOs are quite toxic to aquatic life. Of the OCO's
identified in pulp and paper mill effluents for which toxicity
data are available, the most toxic are the chlorinated phenols.
These chemicals have been found in treated effluents at
concentrations from 4 to 15 ^9/1- Under conditions of 7Q10
low streamflow, in-stream concentrations might approach an order
of magnitude of the LC$Q levels.
(2) Because of time constraints, the potential impacts of the OCOs
on terrestrial organisms were only briefly evaluated. Again,
based on the available data, chlorinated phenols were shown to
be most toxic. Therefore, application of pulp and paper mill
sludge onto forests and agricultural lands may be of concern.
At present, there are no data available on OCO concentrations in
pulp and paper mill sludge.
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(3) Chlorine bleaching at pulp and paper mills can be a major source
of chloroform. During a search of the Toxic Release Inventory
(TRI) data base for information on releases of OCOs, it was
discovered that large quantities of chloroform (classified by
EPA as a "B2" carcinogen) are released to water, land, and air.
by pulp and paper mills. Releases to air are reported to be as
high as 1,700,000 pounds per year from one site.
(4) Concentrations of OCOs in treated effluents are generally much
higher than concentrations of 2,3,7,8-TCDD and 2,3,7,8-TCDF.
Concentrations of OCOs in treated effluents are typically two to
three orders of magnitude higher than concentrations of
2,3,7,8-TCDD and 2,3,7,8-TCDF. However, the CDDs and CDFs are
considered to be much more toxic than OCOs and are presumed to
have the most significant potential for human hazard.
(5) Canada, West Germany, Finland, and Sweden have regulated or
announced intentions to regulate the pulp and paper industry on
the basis of TOX (Total Organic Halogens) or AOX (Adsorbable
Organic Halogens).
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3.
REFERENCES
ADL. 1987. Arthur D. Little, Inc. Exposure and risk assessment of
dioxin in bleached kraft products. Draft report. Washington, DC: U.S.
Environmental Protection Agency, Office of Water Regulations and
Standards. Contract No. 68-01-6951.
API. 1990. American Paper Institute, Inc.
from R. Cavaney to F. Shank.
Letter dated March 15, 1990,
Bonazountas M, JM Wagner. 1984. "SESOIL" a seasonal soil compartment
model. Arthur D. Little, Inc., and DIS/ADLPIPE Inc. for the U.S.
Environmental Protection Agency, Office of Toxic Substances. EPA
Contract No. 68-01-5271.
Bowers JF et al. 1980. Industrial source complex (ISC) dispersion model
user's guide. Volume 1. Research Triangle Park, NC: U.S. Environmental
Protection Agency. PB-80-133044.
Bowman RE, SL Schantz, NCA Weerasinghe, et al. 1989. Chronic dietary
intake of 2,3,7,8-tetrachlorodibenzo-p-dioxin (2378-TCDD) at 5 or 25 ppt
in the monkey: TCDD kinetics and dose effect estimates of reproduction
toxicity. Chemosphere 18(1-6):243-252.
Cook PM. 1989 (Dec. 26). Environmental Research Laboratory-Duluth, MN,
Office of Research and Development, U.S. Environmental Protection
Agency. Review of draft risk assessment from paper mill discharges.
Memorandum to GH Grubbs, Office of Water Regulations and Standards, U.S.
Environmental Protection Agency, Washington, D.C.
Helms J. 1989 (Aug. 11). Office of Water Regulations and Standards,
U.S. Environmental Protection Agency. U.S. EPA/paper industry
cooperative dioxin study full congener analyses. Memorandum to G.
Schweer, Office of Toxic Substances, U.S. Environmental Protection
Agency, Washington, D.C.
nl»
MRCA. 1988. Market Research Corporation of America. Report to the Food
and Drug Administration. Frequency distributions of the total number of
eating occasions in an average 14-day period, by eaters only produced
from the five menu census studies of July 1982 through June 1987 in
partial fulfillment of Contract No. 223-87-2088, Task II, Section
C.1.D(2) and Sections F.I.2(5-6). December 1988.
Nabholz JV. 1989. Bioconcentration factors for 2,3,7,8-chlorinated
dibenzodioxins and 2,3,7,8-chlorinated dibenzofurans. Unpublished.
Washington, DC: U.S. Environmental Protection Agency, Office of Toxic
Substances.
NCASI. 1987. National Council of the Paper Industry for Air and Stream
Improvement. Land treatment effects on wildlife populations in red pine
plantations. Technical Bulletin No. 526. June 1987.
72
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NYDEC. 1987. New York Department of Environmental Conservation.
Niagara river biota contamination project: fish flesh criteria for
piscivorous wildlife. Technical report 87-3, Division of Fish and
Wildlife, Bureau of Environmental Protection.
Pao EM, Flemin KH, Guenther PM, Mickle SJ. 1982. Foods commonly eaten
by individuals: amount eaten per day and per eating occasion. Home
Economics Research Report No. 44. Washington, DC: U.S. Department of
Agriculture.
Thiel DA, Martin SG, Duncan JW, Lemke MJ, Lance WR, Peterson R. 1988.
Evluation of the effects of dioxin-contaminated sludges on wild birds.
In: Proceedings of the 1988 TAPPI Enviornmental Conference.
USEPA. 1987. U.S. Environmental Protection Agency. National dioxin
tudy. Report to Congress. Washington, DC: U.S. Environmental
'rotection Agency. EPA 530/SW-87-025.
ISEPA. 1988. U.S. Environmental Protection Agency. U.S. EPA/paper
ndustry cooperative dioxin screening study. Washington, DC: Office of
later Regulations and Standards. EPA 440/1-88-025.
ISEPA. 1989a. U.S. Environmental Protection Agency. Interim procedures
'or estimating risks associated with exposures to mixtures of chlorinated
Jibenzo-p-dioxins and dibenzofurans (CDDs and CDFs) and 1989 update.
Washington, DC: Risk Assessment Forum, March 1989. EPA 625/3-89-016.
USEPA. 1989b. U.S. Environmental Protection Agency. Bioaccumulative
pollutants in fish - a national study. Volume D study report and
appendices A and B. Draft report. Washington, DC: Office of Water
Regulations and Standards. December 1989.
USEPA. 1989c. U.S. Environmental Protection Agency. 104-mill study
data base. July 17, 1989, version. Washington, DC: Office of Water
Regulations and Standards.
USEPA. 1990. U.S. Environmental Protection Agency. Assessment of risks
from exposure of humans, terrestrial and avian wildlife, and aquatic life
to dioxins and furans from disposal and use of sludge from bleached kraft
and sulfite pulp and paper mills. Washington, DC: Office of Toxic
Substances and Office of Solid Waste. EPA 560/5-90-013.
Yeh GT. 1981. AT123D: Analytical transport one-, two-, three-
dimensional simulation of waste transport in the aquifer system. Oak
Ridge National Laboratory, Environmental Sciences Division, Publication
No. 1439.
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50277-101
REPORT DOCUMENTATION
PAGE
11. RCFORT NO.
EPA 560/5-90-011
4. THI. or* subtm* Integrated Assessment of Risks from Exposure
of Humans, Terrestrial and Avian Wildlife, and Aquatic Life
to Dioxins and Furans Formed During Chlorine Bleaching at
Kraft and Sulflte Pulp and Paper Mills
7. Author!*)
Greg Schweer and Patricia Jennings (Editors)
3- Recipient'* AccMilon No.
S. Report Oft*
7/90
Performing Organization Rept. He.
9. Performing Orgeniiatton N«m* end Addreu
Versar, Inc.
6850 Versar Center
Springfield, VA 22151
10. Prorect/To*k/Work UnK No.
Task 34
11. ContracttC) or GrantfG) Me.
(C) 68-D9-0166
(6)
U. Spontorinc Orzonizotlon Nome and Address
United States Environmental Protection Agency
Office of Toxic Substances
Exposure Evaluation Division
Washington. D.C. 20460
IS. Type of Report 4 Period Covered
Final Report
14.
IS. Supplementary Not**
EPA Project Officer was Thomas Murray
EPA Task Manager was Patricia Jennings
It. Abstract (Limit 200 word!)
This report presents the key findings, assumptions, and uncertainties of an assessment
of risks from exposure bf humans, terrestrial and avlan wildlife, and aquatic life to
dioxins and furans formed during chlorine bleaching at kraft and sulfite pulp and
paper mills. This report contains condensed versions of eight major exposure/risk
assessments and other support documents prepared by program offices within the U.S.
Environmental Protection Agency (EPA), the U.S. Food and Drug Administration (FDA), and
the U.S. Consumer Product Safety Commission (CPSC). Risks were evaluated from roughly
120 potential pathways to exposure to pulp and paper products, pulp and paper mill
sludges, and pulp and paper mill effluents. The development of this assessment and the
individual Agency exposure/risk assessments was coordinated by the Federal Interagency
Working Group on Dioxin-in-Paper. The Background Document to this Integrated Assessment
contains detailed summaries of the Individual exposure/risk assessments.
17.
Analysis . Oaacrlatoii
to. IdoaUBofl/Opnt-Endod T*rm»
Exposure Assessment/Risk Assessment/Pulp and Paper Industry/2,3,7,8-TCDD/2,3,7,8-TCDF/
Dioxins/Furans -»
C. COSAT1 FMd/Group
il. AvalUWHty Sutomont
19. Coeurtty Clact (This ftoport)
Unclassified
21. No. Of «*
2O. Coeurtty CUM (TM< «>
Unclassified
22. Pnc*
I
-tn.it>
Soo Imliucliom on Mwrorme
OTTIONAL FORM 272 (4-77)
(Formerly NTIS-1S)
l Common
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