EXPOSURE AND RISK ASSESSMENT
OF DIOXIN IN
BLEACHED KRAFT PAPER PRODUCTS
BY
ARTHUR D. LITTLE, INC.
TO
MONITORING AND DATA SUPPORT DIVISION
OFFICE OF WATER REGULATIONS
AND STANDARDS
U.S. ENVIRONMENTAL PROTECTION AGENCY
U.S. EPA CONTRACT NO. 68-01-6951
WORK ASSIGNMENT NO. 18
AMENDMENT NO. 1
JUNE 25, 1987
52967-02
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TABLE OF CONTENTS
Page
1.0 Introduction 1
2.0 Objective and Approach 1
2.1 Exposure Assessment 2
2.1.1 Identify consumer products made
from bleached Kraft pulp 2
2.1.2 Characterize use situations 2
2.1.3 Identify and characterize
exposure pathways 3
2.1.4 Evaluate dioxin concentrations in the
consumer products being evaluated 3
2.1.5 Estimate exposure associated with
product/use situations 3
2.1.6 Estimate exposure associated with
incineration of contaminated products 4
2.2 Hazard Identification 4
2.3 Risk Characterization 4
3.0 Exposure Assessment 4
3.1 Identification of Consumer Produces Containing
Bleached Kraft Pulp 4
3.1.1 Production of bleached Kraft pulp 4
3.1.2 Product categories and production data 9
3.1.3 Characterization of product use 18
3.2 Assessment of Potential Availability of Dioxin 25
3.2.1 Estimation of dioxin in bleached Kraft
products 2i
3.2.2 General approach to evaluation of
migration rates 26
3.2.3 Potential release of dioxin from paper
products 29
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TABLE OF CONTENTS
3.2.3.1 Available data 29
3.2.3.2 Uniaediaced diffusion processes 32
3.2.3.3 Migration mediated by external
phase 34
3.2.3.4 Conclusions 36
3.3 Exposure Evaluation of Selected Consumer Products 38
3.3.1 Exposure evaluation of selected consumer
products 38
3.3.2 Estimate of potential dioxin exposure
levels 44
4.0 Risk Assessment 52
4.1 Characterization of Product Uses. Users and
Lifetime Exposures 52
4.1.1 Uncoated paper plates 55
4.1.2 Disposable diaper 55
4.1.3 Sanitary tampon 56
4.1.4 Dinner napkin 56
4.1.5 Paper towel 56
4.1.6 Coffee filter " 57
4.1.7 Uncoated sheet (contact) 57
4.1.8 Uncoated sheet (ingestion) 58
4.2 Risk Estimation 58
5.0 Dlaeuaaton 59
5.1 Uncertainties and AgSV1TO7l?Tt8 59
5.2 Implications of eha Results 60
5.3 Recommendations 62;
References 64
li
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LIST OF FIGURES
FIGURE £ASE
1 End-produce manufacture of
paper/pulp products
Paper producing mills and the
respective paper grades
ill
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LISTJ5EJABLES
IAS1E
I Consuaec produces containing
bleached Kraft (BK) (A) (B) 11-14
Relative percent distribution of
bleached Kraft in selected
product categories 16
Characterization of product use 17
Qualitative exposure/relative risk
matrix 20-23
Relevant Physicochemical Properties
of 2,3.7,8-TCDD 33
Evaluation of specific external
phases 35
Estimates of potential dioxin exposure
levels based on unit consumption of
paper products containing bleached
Kraft (BK) 45-46
Estimates of increased lifetime cancer
risk based on dioxin exposure from
specific use of paper products
containing bleached Kraft (BK) 53-54
iv
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1.0. INTRODUCTION
Results from the National Dloxin Study have indicated that
2,3,7,8-TCDD is present in fish and river sediments collected
downstream from some pulp and paper mills. The highest levels
appeared to be associated with bleached Kraft aills. As a result, a
concern has arisen regarding the potential exposure and risk to
consumers using products containing bleached Kraft pulp and several
research projects have been undertaken. For example, the Pulp and
Paper study, a cooperative effort between the U.S. Environmental
Protection Agency, the American Paper Institute, and the National
Council of the Paper Industry for Air and Stream Improvement, was
initiated to determine possible sources of dioxins and furans in
bleached Kraft mills.
Also, the Monitoring and Data Support Division (MDSD) of the Office of
Water Regulation and Standards of the U.S. Environmental Protection
Agency requested that Arthur D. Little, Inc., as part of its continued
support for the National Dioxin Study, conduct an exposure and risk
assessment study of dioxin In bleached Kraft paper products.
2.0 OBJECTIVE AND APPROACH
The objective of this task was to evaluate and quantify, to the extent
possible with available data, the exposures and the risks to health
that may occur through use of bleached Kraft paper products that may
contain dioxin.
The general approach was to define the universe of bleached Kraft
paper products, to quantify their production and to determine the
potential implications of product use on dioxin exposure. Because .of
the uncertainty regarding the exact mixture of chlorinated
dibenzo-p-dioxin isooers contained in bleached Kraft pulp, the generic
term "dioxin" has been used throughout this study, except where
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reference to che specific isomer (e.g., 2,3,7,8-TCDD) is made.
The potential exposures associated with a variety of use situations
were evaluated and more detailed evaluations were conducted for a few
selected products which appeared to represent greater risks.
There were four major steps in this task.
e Exposure Assessment
e Hazard Identification
e Risk Characterization
• • Report Production
2.1 Exposure Assessment
The exposure assessment was probably the most difficult and uncertain
aspect of this project because aany of the issues had never been
considered, and there was limited information to describe and quantify
product use patterns. The assessment Involved the following steps.
2.1.1 Identify consumer products made from bleached
Kraft pulp
Products were identified through review of the literature and
discussions with staff members of Arthur D. Little, Inc., experienced
in the pulp and paper industry.
2.1.2 Characterize use situations
Additional data were collected to provide information on the use of
these products. In addition, staff members from the Product
Technology Section at Arthur D. Little, Inc., were consulted and
project team discussions were held in order to develop additional
information. The types of information developed during this step
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Included the potential number of users, the extent and/or duration of
average use and descriptions of the typical conditions of use. It was
anticipated that use situations would include usual activities such as
handling sheets of paper and unusual activities such as oral contact
and ingestion of paper by children.
2.1.3 Identify and characterize exposure pathways
In this step exposure scenarios were developed from the use situations
identified in the previous step. Limited data were available for this
purpose, and through use of related information and group discussions,
reasonable scenarios which were consistent with past experience were
developed. This subtask produced the methods which were used to
calculate the exposure for each product/use situation.
2.1.4 Evaluate dioxin concentrations in the consumer
products being evaluated
Although it had been anticipated that some data might be available to
determine initial product concentrations, no such data were
available. Therefore, with the advise of HDSO, it was assumed that
bulk bleached Kraft pulp contains 10 parts par trillion (ppt) of
dioxin.
2.1.5 Estimate exposure associated with product/use
situations
This step was an integration of the results of steps 3 and 4 of the
exposure assessment. In step 3, the methods or models were developed
for the product/use combinations and in step 4 rough estimates of
concentrations were developed. This step resulted in estimates of the
average or range of exposures for each product use situation.
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2.1.6 Estimate exposure associated with Incineration of
contaminated products
Independently, the potential impact of dioxin-eontaainated paper on
dioxln emissions from municipal solid waste incinerators was
considered within the limitations of this task.
2.2 Hazard Identification
This step, while extremely important to a risk assessment, did not
represent a large part of the effort. Primarily, confirmation was
obtained from the EPA Project Officer that the current EPA cancer risk
assessment methodology for 2,3,7,8-TCDD would be utilized.
2.3 Risk Characterization
In this step, the exposure estimates developed above, as well as the
unit risk value from the hazard identification step, were used to
quantify the risks associated with the product/use situations. The
need to identify the uncertainties associated with the estimates was
also anticipated.
3.0 EXPOSURE ASSESSMENT
3.1 Identification of Cqnaumar Products Containing Bleached
Kraft Pulp
3.1.1 Production of Bleached Kraft Pulo
Bleached Kraft pulp is a major component in a wide variety of paper,
paperboard and pulp products. In order to identify and classify
specific consumer end products from an exposure assessment
perspective, it is necessary to understand how various paper and
converted produces are manufactured.
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In general, pulp, paper and paperboard production consists of five
distinct steps: pulping, bleaching, stock preparation, papermaking,
and converting. Figure 1 is a simplified block flow diagram of these
processes. In the discussion that follows, each step is described
briefly.
In the pulping process, cellulosic material, primarily wood, is
converted by mechanical or chemical means into papermaking fibers.
Mechanical processes separate the wood fibers by attrition using large
grind stones or metal plates. The lignin which holds the cellulose
fibers together is not dissolved or separated and appears in the final
product. This method produces a very economical grade of fiber
(groundwood) and is typically used in newsprint.
Semi-chemical processes combine chemical and mechanical steps. The
wood is softened by means of a chemical solution at low temperature.
Excess chemical is removed and the wood is defiberized mechanically,
Essentially all of the lignin remains with the pulp. The primary use
is for corrugating medium, i.e., the fluted middle layer of boxes and
shipping containers.
Chemical pulping Is used to produce fiber for a wide range of products
including printing and writing papers, tissue and packaging paper,
paperboard and fluff pulp. The raw material is reduced to a fibrous
state by cooking with solutions of various chemicals. Essentially all
of the lignin is removed from the wood fiber. The most important
chemical pulping process is the Kraft or sulfate process.
The second step in the production sequence is chemical bleaching.
Typically, the agents used for bleaching include chlorine compounds
and oxygen. The purpose of this step is threefold: to remove any
coloring matter within the pulp, to extract residual lignin and. to
achieve brightness or whiteness, which is desirable in printing and
writing papers, food packaging and sanitary applications. Fibers that
undergo the Kraft chemical pulping process and bleaching sequence are
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PULPING PROCESS
* Chemical (Kraft)
* Seal-mechanical
* Mechanical (Croundwood)
BLEACHING/WASHING
STOCK PREPARATION
* Internal sizing
* Vet strength
* Dyes
PAPERMAKING
* Dyes
+ Surface sizing
* Coatings
END-PRODUCT. CONVERSION
Wet: Dry:
* Coating * Bag
* Laminating * Box
* Impregnating * Printing
FIGURE 1: END-PRODUCT MANUFACTURE OF PAPER/PULP PRODUCTS
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referred co as bleached Kraft fibers or bleached Kraft pulp.
The third step, stock preparation, refers to several operations that
may take place between pulping (and bleaching) and the formation of
the paper or board on a machine and nay include heating, refining and
repulping. The purpose of these operations is to shorten or to
hydrate the fiber for specific paper properties. Fibers from
different processes can be blended in various proportions to produce a
wide range of products. Fillers, dyes, pigments, wet strength resins
and conventional sizing may be added during stock preparation.
As a fourth step, the prepared stock is conveyed to the paper machine
where the paper web is formed and subsequently dried.
The final step in the production of a paper or paperboard product is
the converting process. There may be one or many converting
operations that follow the papermaking process. These operations
include, for example, waxing, gumming, off-machine coating, printing,
bag, envelope, box and container manufacturing. With the exception of
tissue mills, paper and board mills are typically not responsible for
the converting process. This is handled by companies which use the
different grades of paper produced at the paper and paperboard mills
as their raw materials.
The manufacture of paper and paperboard products is distributed among
three distinct industries: paper mills, paperboard mills, and
construction paper and board mills. In Figure 2. the three mill
industries are presented along with the grades of paper and board they
produce. The various grades of paper and board produced are, in turn,
processed by "converters" into consumer end-products.
Since the focus of this study is limited to consumer end-products
which consist primarily of bleached Kraft pulp, various paper and
board grades will not be considered in this analysis. These include
all the grades produced by the construction paper and board mills,
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PAPER MILLS
1
1 1 1 1 1 1 1
NEWSPRINT
UNCOATED
GROUNDUOOO
COATED
GROUNDUOOO
COATED
FREE
SHEET
UNCOATEI
FREE
SHEET
THIN
PAPERS
COTTON
FIBER
PAPERS
1
UNBLEACHED
KRAFT
PAPERS
1 1
BLEACHED
KRAFT
PAPERS
TISSUES
PAPERBOARD
HILLS
r '
III II
UNBLEACHED
KRAFT
PAPERBOARD
BLEACHED
PAPER -
BOARD
SEN I -CHEMICAL
PAPERBOARD
RECYCLED
PAPERBOARD
WET
MACHINE
BOARD
CONSTRUCTION PAPER
AND BOARD MILLS
r
CONSTRUCTION
PAPER
INSULATION
BOARD
HARD
PRESSED
BOARD
FIGURE 2: PAPER PRODUCING HILLS AND THE RESPECTIVE PAPER GRADES
Source: Arthur D. Little, Inc., Based on U.S. Department-of Commerce and
Industry Paper Classification Schemes
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unbleached Kraft paperboard and specific grades from paper mills, such
as newsprint, uncoated/coated grounduood, cotton fibers and the
majority of packaging and industrial papers (except glassine,
greaseproof and vegetable parchment papers).
In particular, consumption patterns of consumer products manufactured
from the following paper, board and pulp categories will be assessed
and used for exposure assessment and risk evaluation:
• coated/uncoated free sheet;
• thin papers;
• bleached bristols;
• special industrial papers: glassine, greaseproof,
etc.;
• tissue papers;
• packaging paperboard;
• non-packaging paperboard; and
• fluff pulp.
3.1.2 Product Categories and Production Data
There are numerous consumer end-products that comprise the bleached
Kraft paper, board and pulp categories. Annual production data for
1985 vere acquired from the published literature, statistics from the
American Paper Institute, Bureau of Census Reports, Industrial
Outlook and other in-house sources. Primarily, these data are
restricted to the larger product categories and are not broken down as
individual produces.
The estimated production tonnages for products whose major component
is bleached Kraft pulp are summarized in Table 1. Examples of
consumer end-products that comprise the respective categories are also
listed. As mentioned earlier, the actual bleached Kraft pulp content
varies among the categories. The remainder may be fillers,
laminations, and resins. For example, only about 75 percent of the
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milk carton stock Is actually bleached Kraft. Alternatively, tissue
papers are almost exclusively bleached Kraft.
Due to the variation in bleached Kraft content, the total production
tonnage is not necessarily equal to the consumption of bleached Kraft
pulp. Using an average percent bleached Kraft content within these
respective categories, the annual pulp consumption can be estimated.
These totals are also presented in Table 1. For the remainder of this
analysis, the per capita usage and percent distribution will be based
on values of consumption of bleached Kraft, not production of
converted end-products.
Several assumptions are implicit in the data of Table 1. The net
effects of imports and exports on the tonnages are assumed to be minor
(+ 10 percent); accordingly, the totals have not been adjusted. The
numbers also include recycled paper that is bleached. Certain product
categories, such as coated free sheets, are "semi-bleached," i.e., the
Kraft pulp undergoes fewer bleach/wash cycles than fully bleached
fiber. However, from the perspective of potential dioxin
contamination in the end product, it is assumed that a semi-bleached
pulp is equivalent to a fully bleached fiber. It is important to note
that there may be variation in the bleached Kraft content within a
given product category; however, in. this analysis an average value has
been used to represent the majority of end-products that fall within
each category. Finally, the examples listed in Table 1 are not
all-inclusive. There is some overlap whereby a given product may be
found in more than one category. Nevertheless, the example products
are representative of typical consumer products containing bleached
Kraft.
The relative distribution of bleached Kraft pulp among the selected
product categories was calculated from the data generated in Table 1,
and is summarized in Table 2. It should be noted that this percentage
breakdown does not account for the sum total of bleached Kraft pulp
produced and consumed in all the grades of paper and allied products,
10
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TABLE 1
CONSUMER PRODUCTS CONTAINING BLEACHED KRAFT(BK) (A) (B)
TOTAL 1985 AVERAGE BK
PRODUCT PRODUCTION PERCENT CONSUHPTION(H)
CATEGORIES THOUSAND BK THOUSAND
STONS/YR (I) STONS/YR
TOTAL PAPER,PAPERBOARD.PULP 27078 22864
** PAPER(C)(DJ** 22198 19121
^PRINTING 1666S 13848
COATED FREE SHEET(E) 5875 70 4113
E.G. PRINTED PRODUCTS
MAGAZINES
PUBLISHED BOOKS
CATALOGUES
ANNUAL REPORTS
UNCOATED FREE SHEET(E) 9625 90 8663
E.G. CORRESP.TABLETS
DESK PADS
LOOSELEAF FILLER
MEMO BOOKS
OFFICE PAPER
TYPING PAPER
FINAN/BUS1NESS FORMS
ENVELOPES
PRINTED BOOKS
STATIONERY
THIN PAPERS 241 100 241
E.G. CIGARETTE PAPER
BIBLE PAGES
LENS TISSUE
CARBON PAPER
BLEACHED BRISTOLS 924 90 832
E.G. WEDDING INVITNS.
CALLING CARDS
FILE FOLDERS
POSTCARDS
11
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TABLE 1
CONSUMER PRODUCTS CONTAINING BLEACHED KRAFT(BK) (A) (B)
PRODUCT
CATEGORIES
TOTAL 1985
PRODUCTION
THOUSAND
STONS/YR (I)
AVERAGE BK
PERCENT CONSUMPTION(H)
BK THOUSAND
STONS/YR
'PACKAGING 593
FOOD WRAPPING 31
BAG&SACK 266
SHIPPING SACK 80
GLASS1NE.CRSPRF.ETC. 216
*TISSUE(F) 4940
TOILET TISSUE 1882
FACIAL TISSUE 354
NAPKINS 579
TOWELLING 1700
WIPER/OTHER 282
E.G. INDUST.CLEANSING
PACKAGING
TOT ALL OTHER 143
E.G. UNCOATEO WRAPPER
CONFETTI
CREPE PAPER
DOILIES
GIFT WRAP
NOVELTIES
COFFEE FILTERS
** PAPERBOARD ** 3948
*PACKAGING 3881
MILK CARTON STOCK(G) 609
E.G.MILK CONT.
YOGURT CONT.
CHEESE CONT.
NON-DAIRY BEVRG CONT
NON-CARB. DRINK CONT.
JUICE CARTON
95
95
95
95
95
95-98
95
95
98
95
95
95
75
563
29
253
76
205
4710
1788
336
567
1615
268
136
3160
3100
457
12
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TABLE 1
CONSUMER PRODUCTS CONTAINING BLEACHED KRAFT(BK) (A) (B)
PRODUCT
CATEGORIES
TOTAL 1985
PRODUCTION
THOUSAND
STONS/YR (I)
AVERAGE
PERCENT
BK
BK
CONSUMPTION(H)
THOUSAND
STONS/YR
FOLDING CARTONS 1780 80 1424
E.G.TOBACCO
MEDICINAL
COSMETICS
CONT.CGELS.SAUCES)
DRY FOOD
PREPARED/PKCD FOOD
PAPEROJPS/LIDS 438 80 350
PAPER PLATES/TRAYS 284 80-90 241
OTHER 656 75-85 525
E.G. OVENABLE TRAYS
LIQUID VESSELS
MOIST/OILY FOOD VESSELS
LINERBOARD U* 90 103
*NON-PACKAGING 67 90 60
E.G.DISPLAY BOARD
** PULP *
932 582
*DISPOSABLE DIAPERS 800 60 480
*FEK HYGIENE PRODS 66 95 63
E.G.SANITARY NAPKINS
TAMPONS
*GERIATRIC ACCESSORIES 66 60 40
E.G.INCONTINENCE PADS
13
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NOTES FOR TABLE I:
A. SOURCES: AMERICAN PAPER INSTITUTE STATISTICS(1985); INDUSTRY
OUTLOOK; PREDICASTS FORECASTS; ADL ESTIMATES. SEE REFERENCES.
B. THIS LIST IS NON-EXHAUSTIVE; SOME PRODUCTS FALL INTO SEVERAL CATEGORIES
C. INCLUDES RECYCLED PAPER THAT IS BLEACHED
D. IMPORTS4EXPORTS INCLUDED IN TOTAL; NET DIFFERENCE HAY BE +/- 10%.
E. ASSUME SEMI-BLEACHED PRODUCTS AND BLEACHED PRODUCTS EQUIVALENT
FROM RISK PERSPECTIVE.
F. DOES NOT INCLUDE FLUFF PULP CONSUMPTION IN SANITARY TISSUE
G. TOTAL WEIGHT INCLUDES BK PLUS COATINGS.LAMINATIONS, ETC.
H. BK TONNAGE REPORTED DOES NOT INCLUDE CONTENT IN OTHER CATEGORIES OF
PAPER PRODUCTS NOT CONSIDERED IN THIS ANALYSIS.
THUS. ACTUAL BK CONSUMPTION EXCEEDS TOTAL LISTED HERE.
I. STONS/YR - SHORT TONS(2000 LBS/STON) PER YEAR
14
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but mainly represents the relative consumption among those product
categories whose main component is bleached Kraft. From Table 2, it is
evident that bleached Kraft consumption is dominated by the printing
papers; the tissue papers are at a distant second place, followed by
the packaging paperboard. The fluff pulp and packaging papers utilize
a relatively small fraction of the total bleached Kraft tonnage.
If an exposure assessment were based purely on relative tonnages, then
several product categories vould not be considered for further
analysis. However, the per capita annual consumption for specific
products provides a more realistic perspective on bleach Kraft tonnage
consumed. For example, the relative distribution of both disposable
diapers and milk carton stock is about 2 percent each. However, the
size of the population using disposable diapers, namely infants, is
significantly smaller than the size of the population using milk
carton/Juice cartons, etc., i.e. children, adolescents, adults, etc.
Therefore, the actual per capita consumption of bleached Kraft for
disposable diapers would greatly exceed that of products made from
milk carton stock. This analysis is illustrated for the various
product categories in Table 3. Note that the second column "Annual
Bleached Kraft Production" includes the fractional content as listed
in Table 1.
The user population, tabulated in the third column of Table 3,
specifies whether typical products within a given category are used by
a segment of the population, or the total US population. Products in
categories such as tissue or packaging paperboard are generally used
by all age brackets. For the printing papers and packaging papers,
children under five years of age are excluded. For a specific use of
an uncoated free sheet, which may be chewed and/or eaten, such as a
spitball, however, the user population consists of children between
the ages of 5 and 13. The disposable diapers are specific for
children under three years of age. The use of feminine hygiene
products is limited to the female segment of population between the
ages of 10 and 50. Finally, the geriatric accessories are primarily
15
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TABLE 2
RELATIVE PERCENT DISTRIBUTION OP BLEACHED KRAFT IN SELECTED PRODUCT CATEGORIES
TOTAL PAPER.PAPERBOARD.6i PULP
100.0
* PAPER ** 83.6
^PRINTING 60.6
CTD FREE SHEET 18.0
UNCT FREE SHEET 37.9
THIN PAPERS 1.1
, BL. BRISTOLS 3.6
^PACKAGING 2.5
FOOD WRAPPING 0.1
BAG&SACK 1.1
SHIPPING SACK 0.3
CLASSINE.CRSPRF 0.9
*TISSUE 20.6
TOILET TISSUE 7.8
FACIAL TISSUE 1.5
NAPKINS 2.5
TOWELLING 7.1
UIPER/OTHER 1.2
TOT ALL OTHER 0.6
** PAPERBOARO ** 13.8
^PACKAGING 13.6
MILK CARTON STOCK 2.0
FOLDING CARTONS 6.2
PAPERCUPS/LIDS 1.5
PAPER PLATES/TRAYS l.l
OTHER 2.3
LINERBOARD 0.4
*NON-PACKAGING 0.3
** PULP * 2.5
*DISP. DIAPERS 2.1
*FEH HYGN PRODS 0 3
*CERIATRIC ACCESS 0.2
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TABLE 3
CHARACTERIZATION OF PRODUCT USE
PRODUCT
CATEGORY
ANNUAL BK USER
PRODN POPULN.
(000) CATEGORY
STONS/YR (A)
** PAPER **
*PRINTING
COATED FREE SHEET
UNCOATED FREE SHEET
THIN PAPERS
BLEACHED . BR1STOLS
^PACKAGING
FOOD WRAPPING
BAGS.SACK
SHIPPING SACK
GLASS INE.GRSPRF, ETC.
*TTOIL!T TISSUE
FACIAL TISSUE
NAPKINS
TOWELLING
WIPER/OTHER
TOT ALL OTHER
** PAPERBOARD **
* PACKAGING
MILK CARTON STOCK
FOLDING CARTONS
PAPERCUPS/LIDS
PAPER PLATES/TRAYS
OTHER/OVENABLE BRD
LINERBOARD
*NON- PACKAGING
** PULP *
*DISPOSABLE DIAPERS
*SANIT NAPKINS&TAMPONS
*GERIATRIC ACCESSORIES
8663
241
832
29
253
76
205
nn
36
,
1615
268
136
/e,
457
350
24 L
525
103
60
480
63
40
5
5
5
1
1
1
1
1
1
1
1
1
1
2
3
4
PER CAPITA
USAGE
KG/PERSON
/YR
PRODUCT
USE/
MISUSE
16.9
35.7
1.0
READING/CORRESPONDENCE
INGESTION
READING
SMOKING
TYPING
CLEANING
3.4 CORRESPONDENCE
0.1 PACKAGING
1.0 PACKAGING
0.3 PACKAGING
0.8 PACKAGING
6.8 WIPING/CLEANING
1.3 WIPING
2.2 WIPING
6.1 DRYING
GREASE ABSORPTION
1.0 WIPING
0 5 CLEANING/WIPING
1.7 BEV STORAGE
5.4 FOOD STORAGE
L.3 HOT/COLD LIQUID SERVICE
0.9 FOOD SERVICE
2.0 HEATING FOOD
0.4 PACKAGING
0.2
40.3 INFANT CARE
0.8 FEMIN. HYGIENE
16.4 ELDERLY INCONT.
AOTulER°POPULATIOT CATEGORIES DEFINED AS FOLLOWS:
1- TOTAL US 1985 POPULATION
2- CHILDREN < 3 YEARS
5- TOT POPULN > 5 YRS
6- CHILDREN BETWEEN 5-13 YEARS
(MM)
S38.74
10.82
71.06
2.20
220.70
30.11
17
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used by the elderly population (greater than age 65) with the medical
condition of incontinence. The sources for population data used in
Table 3 are the U.S. Bureau of Census (1985) and the National Center
for Health Statistics (1986).
Characterization of product use provides an estimate of the
consumption for a typical user of a given product. Referring to the
example mentioned earlier, it is apparent that, although the tonnages
of bleached Kraft are similar for milk carton stock and disposable
diapers, the relative per capita consumption, as shown in the fourth
column, indicates a difference in bleached Kraft consumption of more
than a factor of twenty.
Based on the per capita consumption for all categories in Table 3, the
printing paper products and pulp categories indicate a high level of
consumption; tissue and packaging paperboard products reflect
intermediate levels and the packaging papers represent low bleached
Kraft consumption levels.
The last column in Table 3 exemplifies Che use (or misuse) of typical
products. Definitions of product uses provide further insight into
potential routes of dioxin exposure, i.e., how is the product used,
and how does it come in contact with the user? While the bulk of the
printing papers are used for reading and writing, there are some
exceptions: fractions of uncoated sheets may be chewed or ingested
and thin papers may serve as lens tissue, cigarette papers or
carbonizing paper. Similarly, in the tissue category, the majority of
produces are used for wiping or cleaning purposes; however, with the
increased use of microwave cooking, paper towels may also be used for
absorption of grease, e.g., in cooking bacon. Numerous scenarios of
product use/misuse can b* postulated. As the exposure assessment and
analysis of exposure routes are discussed further, the rationale for
selection of particular scenarios and products will become evident. *
3.1.3 Characterization of Produce Use
In conducting a product-related exposure assessment, the product must
18
-------
be characterized both in terms of the type and size of the user
population and in terns of its patterns of use. Estimation of per
capita consumption essentially defines the user population that is
exposed. There are several parameters- that characterize the use of a
given paper product, such as the duration, frequency and multiplicity
of use. Each of these parameters can be ranked in a semi-quantitative
manner, so that low-risk categories nay be screened our. As a result,
further analysis can focus on potentially high-risk product types. In
Table 4, a qualitative risk matrix is presented, characterizing both
product use and the user.
The first column lists the product categories. The second column
defines three levels of per capita consumption of bleached Kraft,
based on data from earlier tables, i.e., low refers to less than 1
kg/person/year; medium implies between 1 and 10 kg/person/yr; and high
refers to use in excess of 10 kg/person/yr. The unit use duration,
which is shown in the third column, may be short, i.e., on the order .
of a few seconds, as with facial tissues. Alternatively, the use may
be of medium duration, on the order of a few minutes, as with coated
paper cups or extended over one or more hours as with a large Juice
carton.
The relative frequency of use, tabulated in the fourth column, is
based on annualized daily averages. The criteria needed to
distinguish frequency levels are as follows: low implies usage not
exceeding once per week, such as use of shipping sacks; medium refers
to a range between once per week and once per day, such as use of
paper plates; high-frequency Indicates use exceeding once a day, such
as use of disposable diapers.
The multiplicity of use for each produce category is shown in the
fifth column. Essentially, it answers the question: can repeated
exposure occur from the same product (not product type)? Due to the
basic disposability of the majority of paper products, such as single
19
-------
TABLE 4
KJ
o
PAPER
PRODUCT
AND
USAGE
PAPER:
PRINTING PAPER
COATED SHEET
-READING
UNCT SHEET
-READ/CORRESP
-SPITBALLS
THIN PAPERS
-READING
-SMOKING
-TYPING/CARBON
-CLEANING/WIPING
BL BRISTOLS
-CORRESPOND.
PACKAGING
WRAPPING
-PACKAGING
BAG&SACK
- PACKAGING
SHPNC SACK
- PACKAGING
QUALITATIVE EXPOSURE/RELATIVE
RISK MATRIX
PER
CAPITA
CONSUME .
L.H.H(A)
H
H
»
H
>N
'ING
H
L
H
L
DURATION
PER USE
OF UNIT
S.M,L(B)
S
S
S
S
H
S
S
S
H
M
M
RELATIVE
FREQUENCY
OF USE
L,H,H(C)
H
H
H
H
H
H
H
M
L
L
L
IS USE
PER UNIT
REPEATED?
N,Y (D)
Y
Y
N
Y
N
N
N
N
N
N
Y
EXPOSURE
ROUTE
DIOXIN EXTRACTION MEDIUM
SKIN
OILS
BODY
FLUIDS
NON-OILY
FOODS
OILY
FOODS
D
I
D
I (F)
D
D
D
D
D
*
*
*
*
*
-------
TABLE
N>
QUALITATIVE EXPOSURE/RELATIVE
DA nc*n
PAPER p£B
PRODUCT CAPITA
AND „ CONSUMP.
USAGE L,M,H(A)
TISSUE
TOILET
-WIPING
FACIAL
-WIPING
NAPKIN
-WIPING
TOWELLING
-DRYING
-CREASE ABSORP
WIPER/OTHER
-WIPING
TOT ALL OTHER
-CLEANING/UIP
PAPERBOARD:
PACKAGING
MILK CTNS
-BEVER STORAG
FOLD CTNS
-FOOD STORAGE
PAPERCUPS/LIDS
-HOT/COLD LIQ
PLATES/TRAYS
-FOOD SERVICE
OVENABLE BRD
-HEATING FOOD
LINERBRD
-PACKAGING
NON-PKGINC
M
M
M
H
M
L
M
M
M
M
L
L
DURATION RELATIVE
PER USE FREQUENCY
OF UNIT OF USE
S.M.L(B) L.M.H(C)
S
S
M
M
S
L
L
M
M/L
M
L
L
H
H
H
M
M
H
M
M
M
L
L
L
RISK MATRIX
IS USE
PER UNIT
REPEATED?
N.Y (D)
N
N
N
N
N
N
N
N
N
N
N
N
"oUTE^ DIOXIN EXTRACTION MEDIUM
D *
D *
D *
D *
I
D *
D *
I * *
I
1 *
1 * * *
I *
* *
i
-------
TABLE 4
PAPER
PRODUCT
AND
USAGE
PULP:
DISP DIAPS
-INFANT CARE
SAN NAP & TAMP
-FEM. HYGIENE
INCONT PADS
-ELDER INCONT
QUALITATIVE EXPOSURE/RELATIVE
RISK MATRIX
PER
CAPITA
CONSUNP.
L,H.H(A)
H
N
H
DURATION
PER USE
OF UNIT
S.N.L(B)
L
L
L
RELATIVE
FREQUENCY
OF USE
L.M.H(C)
H
H
H
IS USE
PER UNIT
REPEATED?
M,Y (D)
N
N
N
EXPOSURE
ROUTE
D.I
(G)
DIOXIN EXTRACTION MEDIUM
OILY
FOODS
*
*
KJ
K)
-------
NOTES FOR TABLE 4:
A CENSufDATA^IS^EFINEfi JsSFOLLOWS?°DUCTI°N T°NNACE &
H- HIGH; EXCEEDING 10 KG/PERSON/YR
B. BASED ON ADL ESTIMATES:
TSE S5iIIRIA USED TO DISTINGUISH THE TIME ARE AS FOLLOWS
S- SHORT; ON THE ORDER OF SECONDS : E.C FACIAL TISSUR
M- MEDIUM- ON THE ORDER OF MINUTES*: EC CIGARETTES
L- LONG; 6N THE ORDER OF HOURS ; E.G.? DISPOSABLE DIAPERS
C. BASED ON ADL ESTIMATES:
CRITERIA USED TO DISTINGUISH THE FREQUENCY OF USE ARE AS R
fe BtjpaRap^a^ffiJUT^^-yfs^
AH- HIGH: EXPOSURE TO UNfT EXCEEDS ONCE PER DAY •E C DISPnrlpppS w""
ANNUALIZED DAILY AVERAGES ARE ESTIMATED BASED ON'slcMENT^OF USEREpOPULATION
ro
E. ^^^^"JJS^DIOXIN FROM A GIVEN PAPER PRODUCT INCLUDE THE FOLLOWING
I - INCESTION
F.
c
H. "USE- IS DEFINED AS - CONTACT WITH AN EXTERNAL PHASE.
-------
service dinnerware, most of the products are not used repeatedly
However, the reading/writing papers and shipping sacks may be reused,
and exposure may occur with each use of the same product unit.
Assuming the three use parameters are equally important, certain
generalizations can be made. According to Table 4, a typical user of
printing paper product uses a large number of sheets, each for a short
period of time, and so may be exposed to the same sheet more than
once. Packaging papers, on the other hand, are used infrequently, for
an intermediate duration. Tissue papers, like printing papers
consist of high frequency, short/medium duration uses. Paperboard
used for food packaging tends to be used for extended periods of time
although the frequency is not high. Finally, the products in the pulp
category are typically used frequently and for . lengthy period of
time.
In order to determine user exposure, a mechanism for dioxin release
from a product to a user must be defined. For this study, an
-external phase matrix penetration" mechanism is assumed. In order to
release the dioxin from . paper, board or pulp matrix, an external
phase or solvent, such as air, skin oil, body fluids or water must
penetrate the matrix, solublize and extract the dioxin and come in
direct contact with the user. The modes of contact, termed -routes of
exposure," may be via ingestion or dermal absorption. External phases
chat contact the outer skin, such as skin oil touching a sheet of
paper, result in exposure by -dermal absorption"; external phases that
pass directly to the gastro-intestinal tract, such as by chewing
paper, result in exposure by "ingestion." A third route of exposure,
where the external phase may come in contact with internal mucous
membranes, e.g., with a sanitary tampon, is assumed to be equivalent
to ingestion in this analysis.
In Table 4, respective potential exposure routes are characterized for
each of the product categories. Additionally, one or more relevant
external phases (or extraction media) are identified for each of the
24
-------
product categories. For the majority of products where outer dennal
absorption is the primary exposure route, skin oils are the extraction
media; the single exception is body fluids (urine) on a disposable
diaper. Where ingestion of the external phase containing dioxin is
involved, non-oily and/or oily foods usually comprise the external
phases. Where internal dermal absorption occurs, body fluids are the
extraction media.
The ultimate risk to the user depends not only on the quantity
frequency and duration of use, but also on the route of exposure and
extraction medium. These last two parameters lead into a further
analysis of dioxin availability, migration rates, and dioxin release
from a product. In the sections that follow, these topics are
discussed in greater detail.
3-2 Assessment of
3-2-1 Estimation of Dtqxln in ftleaeheti Ttr*f+ Produers
•^'^•^••••"TiiTrift—i&MA±-+t^£ A.tfymp i^j
The detection of dioxin in fi,h and sediment samples collected near
bleached Kraft pulp and pap.r mills has prompted many questions
Several studies .„ currently underway to evaluate the formation and
fate of dioxin in th. bleached Kraft process and to determine the
potential for dioxin contamination in bleached Kraft pulp and paper
products. However, th.s. studies are not complete and the data are
not yet available.
For th. purpose, of this exposure and risk assessment, the EPA has
provided a hypothetical contamination l.v.l of 10 ppt (pg/g) for all
bleached Kraft pulp and paper. As discussed previously, no provision
has been made for decreasing or increasing the assumed level of
contamination for semi-bleached or highly bleached (several passes
through th. chlorination process) products. It has been assumed.
however, that th. 10 ppt contamination is only in the bl.ached Kraft
portion of th. product and, therefore, the product contamination level
25
-------
has been adjusted based on the estimated percentage of bleached Kraft
pulp or paper contained in each specific product (See Table 1). This
assumption is reasonable in light of preliminary data indicating that
the highest environmental contamination has been associated with
bleached Kraft mills. However, a survey of dioxin contamination in
consumer paper products is needed in order to document the fate of
dioxins formed during pulp and paper manufacture.
There are no available data describing the potential distribution of
the dioxin contamination within the pulp and paper matrices. The
dioxin molecule could be chemically bonded or adsorbed to paper
components, or it could be loosely incorporated into the matrix and
available to migrate. The chemical characteristics of dioxin suggest
that it will probably be adsorbed to the molecular structure of the
paper matrix; however, in the absence of any specific data and in
order not to underestimate potential exposure, it has been assumed
that the dioxin is freely available.
Finally, it is acknowledged that the type of coating and the actual
coating process used on pulp and paper products may affect the
contamination. For example, the coating process may actually initiate
an extraction process resulting in . lower dioxin concentration in the
paper product its.lf and a more concentrated contamination in the
coatings; or there may be a continual partitioning between the product
and the coating; or the coating may be a barrier to dioxin migration.
Due to the lack of any data describing the potential behavior of
dioxin contamination in coated paper products, it has been assumed
that there is no transport to coating materials during or after the
coating process and that there is no detectable migration from a
coated product.
3-2-2 general Approach to Evalu^ti^ «f *!,*»,.*«„ BMt.f1
The overall migration rate of a contaminant from « specific matrix
depends on the rate of diffusion within the matrix and the rate of
26
-------
dissolution and dispersion in an external phase in contact wich the
matrix. Migration is Influenced by properties of the contaminant, the
matrix and the external environment; interactions among the
contaminant, the matrix and the external environment; and the use
conditions. Some specific factors potentially affecting contaminant
migration during a specific use include:
• size of migrant • molecular weight,
• physical and chemical properties of the migrant,
e concentration of the migrant,
• interaction of the migrant with the matrix.
« characteristics of matrix - rigidity/flexibility,
• contact/penetration of matrix by external phases,
• solubility of migrant in external phases,
• duration of use, and
e temperature.
Migration from a specific matrix is often controlled within the
matrix. In such cases, migration is a function of the initial
concentration in the matrix and the diffusion coefficient of the
migrant/matrix pair.
The driving force for migration is the concentration gradient of the
migrant within the matrix and the rate of migration is directly
proportional to this gradient. According to theory, migration will
continue as long as there is a concentration gradient. However, there
may exist cases In which some of the migrant species are bound and
unavailable for migration. For example, this has been reported for
very low concentrations of monomer in some plastic materials. Most
available studies documenting contaminant migration involve synthetic
polymers and concentrations of ppm or higher. No information was
found to support or refute a "zero migration- concentration for paper
products.
Migration through a matrix toward the surface may occur through a
27
-------
diffusive process in which migrating molecules "jump" thermally from
one position to a neighboring position. The mechanisms involved are
similar to those by which solutes move through liquids and can
theoretically be characterized in terms of diffusion coefficients
Diffusion through solid matrices is much more sensitive to migrant
molecular weight than is diffusion in water because the migration of
small molecules requires only minor shifting of the matrix, while the
movement of larger molecules from sit. to site may necessitate the
simultaneous reorientation of segments of the matrix. Thus, diffusion
rates in solid matrices (e.g., polymers) are relatively low and
decrease sharply as migrant size increases (Till ec al., 1983).
In addition to the size and nature of the migrant, other factors
related to the thermal energy (i.e., activation energy) needed to
stimulate the "Juaps" include the stiffness of the matrix and the
presence of penetrants. plasticizers, proc.ssing aids or other
molecules which may affect the flexibility of the matrix or the
movement of the migrant.
Elevated temperature, are expected to decrease the activation energy
needed for movement within a matrix and increase diffusion
Temperature-induced effects may include: increased migrant vapor
pressure, altered partitioning between migrant and matrix, altered
behavior of penetrants or other processing aids within the matrix In
a study of migration of various contaminants in polymeric materials
increases In diffusion coefficient, of on. to four orders of magnitude
were observed over the temperature range of 4«C to 40'C (Till et al
1983).
Once a migrant r.aches the interface bectfeen ^ ^^ ^ &
contacting external phase, it dissolve. !„ the external phase and
effects a partition equilibrium. Assuming constant migrant
concentration, migration controlled by diffusion is expected to occur
at a rate proportional to the square root of time. However, if
migrant concentration in the matrix drop, below 50% of the initial
28
-------
concentrator, or If the migration concentration in the external phase
approaches 10-20% of saturation levels, the rate of migration is
expected to drop below that which would be associated with the square
root of time relationship. If che external phase is not well mixed
boundary conditions may also reduce the migration rate The
interaction of the migrant with the external phase is generally
defined as a solubility and partitioning issue; the solubility of the
migrant in the external phase, volume of external phase available
time of contact and temperature during contact are all important in
evaluating dissolution and dispersion. External phases which are able
to remove migrating species as fast as they appear at the surface of
the matrix are considered -sinks"; under these conditions, migration
is dependent on diffusion and solubility considerations in the matrix.
The interaction between external phase and the matrix itself i, also
important. Penetration of the external phase into the matrix can
accelerate and may control the migration process. After the external 4
Phase reaches eh. contaminant, solubility and partitioning again
become important issues.
3'2'3 Potential
3-2. 3.1 Availabl
The technical literature was searched for information that could
provide insight into the mechanism by which dioxin or any other
chemical migrate, fro. paper products. Because information specific
to dioxin migration was thought unlikely to exist, the search
encompassed the migration of any chemical fro. paper products Of
intereat was th. form and location of the che.ic.1 in the paper the
rates at which chemical migrates from paper and factors that could
affect the migration process.
Four data bases were searched:
29
-------
• Chemical Abstracts -- 1977 to present,
• Food Science and Technology •- 1969 to present,
• Pira -- 1975 to present, and
• World Surface Coatings Abstracts -- 1976 to present.
The first two databases were searched through the online services of
Dialog Information Services, Inc. and the latter two through Pergamon
InfoLine. Inc. Pira is the Paper and Board, Printing and Packaging
Industries Research Association (United Kingdom).
A variety of search strategies and key words were used. Ultimately.
the most productive was the combination: MIGRA(...) and PAPER. Of
the four databases, the first two yielded the most apparently relevant
abstracts. Fifteen articles were obtained and reviewed. In selecting
the articles for acquisition, emphasis was placed on those in English,
French. Italian or German that could be rapidly obtained. None of the
non-English articles were translated; however, they were inspected for
useful tables and figures.
Of the fifteen articles, six have ,0». pertinence to the present
problem, although none provides quantitative information that would be
useful for substantiating estimates of dioxin migration.
Whicfield et al. (1984) associate the contamination of cocoa powder
with the presence of chlorophenols in the paper of the sacks in which
the powder was packaged. The authors cite Voss, et al. (1980) who
state that certain chlorophenols are formed during the bleaching
nrnfmam
process
The migration of polychlorinated biphenyls (Aroclor 1242) from
bleached Kraft to four foods was reported by Stanovick et al. (1973).
The PCB-containing paper was produced by blending the pulp with
"carbonless" carbon paper. The foods were dry cereal, cereal grain* a
cake mix containing 12% shortening and table spread. At typical
commercial ratios of food weight to package surface area, the
30
-------
migrations from paper initially containing 20 and 160 pp» PCB produced
concentrations in th. foods ranging fro» 0.1 to 4.3 ppm after periods
of 60 or 90 days. Food type appeared to have little or no effect on
the amount of migration. In other tests, plastic files and waxed
glassine paper were placed between the contaminated paper and the
food. Migrations were generally reduced with the polyvinylidene
chloride film and the glassin. but not with the polyethylene film
Although the procedures section of this publication indicates that
data were obtained at several times during th. 60 or 90 day durations
of the exposures, only the end point v.lu., are reported. Presumably
the time data along with details on th. experiments could be obtained
from the authors. From such data the mechanisms and rates of
migration might be discernible and, perhaps, applied to the
elucidation of the dioxin migration process.
Two other publications discuss the migration of N-nitrosomorpholine
(NMOR) from paper products to food., s.n and Baddoo (1986) compared
the amounts of NMOR found in margarine comm.rcially packaged in waxed
paper, polymer-coat.d pap.r and alu.inum-b.cked paper. In three of
five cases, 0.5, 1.1 and 1.4 ppb NMOR were found in the margarine
close to its interface with the waxed paper packaging. The initial
amount of NMOR in each packag. ranged from 5 to 34 nanograms. No NMOR
was detected in th. margarine ' fro. th. packages of the other
materials, although NMOR wa, pr.,.nt ln the packaglng> ^
publication is deficient of any infor-mtion with which to estimate
migration rat.,. For example, neither th. storag. times nor package
dimensions nor amount, of margarine ar. given. Hotchkiss and Vecchio
(1983) report the migration of NMOR to flour at 100'C. However, no
detail, on th. ti.es or exposure areas are given.
Two foreign language articles that could have r.levance are laccarino
et. al. (1982) and Falandysz and Ganowiak (1982).
As mentioned earlier, these studies may not b. directly applicable to
dioxin migration fro. paper product, b.caus. of the different
31
-------
chemicals, higher contamination levels, different matrices and
different conditions used. Therefore, for the purpose of this study,
several assumptions regarding dioxin migration have been made and are
discussed below.
3-2-3-2 Unmediated
Table 5 presents some physicochemical properties of 2,3,7,8-TCDD that
are relevant for predicting the potential migration from solid
matrices. As discussed in Section 3.2.2, diffusion is expected to be
highly dependent on the size and nature of the migrant. The high
molecular weight and low vapor pressure of 2,3,7,8-TCDD indicate that
unmediated diffusion through solid matrices is not expected to be
significant. In fact, mobility of 2,3,7,8-TCDD in environmental
soils, which are generally more porous than paper, has been shown
repeatedly to be very low, e.g., 10 c. migration over 12 years
(Freeman and Schroy, 1985). Furthermore, .t concentration levels on
the order of 10 ppt, there may be very little driving force for
diffusive migration.
External factors such as microwaving or exposure to elevated
temperatures could possibly affect dioxin mobility and increase the
potential for diffusion. However, -'there are no data describing these
effects and they have not been addressed within the scope of this
study.
The disposition of dioxin molecules within the paper matrix may also
affect it. rate of migration. For example, to the extent that the
dioxin molecules may be adsorbed or chemically bonded to the matrix.
the rat. of migration may be reduced. However, there are no available
data describing the extent of sorption or bonding of dioxin in the
paper matrix. For the purposes of this study and to assess maximum
migration potential, it has been assumed that the dioxin molecule \s
unbound.
32
-------
TABLE 5
Relevant Phvslct
Formula
Molecular Weight
Melting Point
Vapor Pressure (nun Hg)
25'C
25'C
30*C
Log Octanol Water
Sourea
CiaH4Cl40,
321.97
305'C
1.5 x 10"»
7.4 x 10"10
3.5 x 10~»
Partition Coefficient 6.15-6 84
dog Kow)
Solubility (mg/L) in:
o-Oichlorobenzene
Chlorobenzene
Benzene
Chlorofona
n-Octanol
Methanol
Acetone
Water (25*C)
Water (20-22'C)
Water (22'C)
Water (20-25'C)
1400
720
570
370
48
10
110
3.17 x 10"*
7.91 x 10'«
1.93 x 10"«
Schroy
. (1985)
Freeman and Schroy (1986)
Podoll ££ al. (1986)
Schroy at al. (1985)
Marple fi£
2.0 x 10~«
Schroy ££
Schroy e^
Schroy e^
Schroy ££
Schroy ej
Schroy e^
Schroy ej
Schroy e^
Adaas and
Marple ££
Mackay ££
Al.
Al-
(1986)
(1985)
(1985)
(1985)
(1985)
(1985)
Al- (1985)
Al- (1985)
Al- (1985)
Blaine (1986)
Al- (1986)
Al. (1985)
33
-------
In summary, diffusion of dioxin within the paper matrix and from the
surface of paper products is expected to be very low due to its high
n-olecular weight and low vapor pressure at room temperature. Products
for which unmediated diffusion represents the only migration process
will not be considered further.
3'2'3-3
Dioxin migration can be facilitated by an external phase that
penetrates and swells the paper product and then solubilizes the
dioxin. Because air does not swell paper and because the vapor
pressure of dioxin is so low. little or no migration is expected with
this external phase. It is also likely that coatings on products
effectively prevent the external phase fro. contacting the paper
matrix and solubilizing the dioxin. Therefore, migration from dry
paper products and from coated paper products under normal use
conditions is expected to be negligible and these product categories
have been eliminated from further consideration.
External phases that are likely to contact and penetrate consumer
paper products were evaluated. The mass of dioxin estimated to be
available in a specific product and the volume of external phase
associated with a specific use were reviewed to determine whether
saturation conditions might be expected. Table 6 lists the types of
external phases considered, the types of products expected to be
contacted, and a conservative estimate of the volume of external phase
expected to be encountered in a specific use.
Using the wight of dioxin available in a specific product and the
volume of external phase shown in Table 6. estimated concentrations of
dioxin in the external phases can be calculated. These concentrations
should be considered maximum concentrations, since all the dioxins .in
the product may not be contacted by the assumed volume of external
phase: and in an actual product, all the dioxin may not be freely
available.
34
-------
TABLE 6
tn
External
Phases
Water
• Aqueous foods
Body Fluids
e Saliva
• Skin oils
• Blood
• Urine
Oils
• Oily foods
Product
Contacted.8
• paper towel
• coffee filter
• uncoated sheet
• uncoated sheet
• paper towel
• dinner napkin
• uncoated plate
• tampon
• diaper
e paper towel
• uncoated plate
Dioxin (pg)
Per Unit
30
63
0.4
36
30
93
148
24
420
30
148
Approximate
Volume (raL)
External Pb,****
•an
j\j
1000
1
1.
0.001
0.001
0.001
0.001
in
JU
so
30
30
Maximum Estimated
Concentration in
External P^flfje (ne/l\
. . .6
1 x 10 *
6 x 10~8
. , -7
4 x 10
4 x 10~i?
3 x io"<
9 x 10":
2 x 10"1
-7
8 x 10
8 x 10'6
-6
1 x 10~
s v in'6
See Table 7
assumed to be associated with specific use of product, as discussed in Section 3.3.
-------
The concentration estimates In Table 6 can be compared with the
solubility data given in Table 5 to determine whether solubility
limitations should be considered. The different solvents for which
solubility data are available do not directly correspond to the
selected external phases; however, some general assumptions about the
solubility of dioxin can be made. The concentrations estimated for
dioxin in aqueous solution, are less than the aqueous solubility
concentrations cited in the literature, and concentrations estimated
for dioxin in oily foods and in skin oil, «. also less than
solubility concentrations cited in the literature for most non-polar
organics. Therefore, for these three categories, solubility i, not
expected to limit the extent to which the dioxin in the paper matrix
will be transported by the external phase. There are no solubility
data available for the other body fluid, cited; however, the capacity
of saliva, blood, and urine for dioxin i. expected to be greater than
that of pure water, and the maximum estimated concentration, given in
Table 6 probably do not exceed solubilities. In summary, therefore
all of the external phases specified in the following sections of this
report may be considered -sink,- with respect to their ability to
solubilize dioxin present at 10 ppt in the selected products
3.2.3.A Conclusions
For the purpose of evaluating the exposure to dioxin associated with
normal «.. of selected bleached Kraft paper products, the following
observation, about the release of dioxin fro. the products have been
made.
1. There are no specific migration rate data available for
dioxin-contaminated paper products.
2. Unmediated migration is expected to be negligible at 10 ppt
dioxin; migration to air is not expected to be signific
Leant.
3. Matrix penetration/alteration is necessary for release of
dioxin from paper products.
36
-------
5.
Penetration of representative external phases through
coating materials is not likely to be significant; dioxin
migration from coated paper products is assumed to be
negligible.
For several representative external phases it is unlikely
that saturation and partitioning limitations control the
migration process; this conclusion was based on conservative
assumptions in that dioxin availability was maximized and
the external phase volume was minimized.
Since the migration of dioxin will most likely occur under
conditions of external phase penetration. individual
estimates of dioxin availability will be made for specific
uses of specific paper products; penetration will depend on
time, temperature, contact area and depth, external phase
volume and other considerations.
37
-------
3-3 Exposure Evaluf
3-3.1 Prpduct Selection Crf^frf||
Converted end-products which are primarily comprised of bleached Kraft
pulp cover a broad spectrum of consumer use,. The analysis of
relative tonnages and per capita distribution, as described in Section
3.1, combined with the evaluation of dioxin availability and
migration, as discussed in Section 3.2, strongly suggest various
products and categories that can be dismissed from further
consideration in terms of relative exposure and risk. Specific
products with the highest potential for exposure have been selected
based upon a qualitative evaluation of the parameters summarized in
Table 4, which include the following: per capita consumption
exposure routes, product us. characterization and external phases.
End products which fall in high per capita consumption categories may
result in an increased exposure - .ither vla the ^^ absorpclon J
the ingestion route. In terms of exposure routes, if a user were
exposed to an available ^ of dloxlnf only a fc
would actually be absorbed, depending on the mode of contact. This
fraction, known M <*. .bsorption efficiency, range, from about 2
percent for direct external skin contact (Poiger and Schlatter, 1980,
to 30 percent for ingestion of product containing dioxin (McConnell.'
et al., 1984,, to 100 percent for inhalation of airborne dioxin (ADL
estimate). For absorption through internal mucous membranes, an
efficiency of 50 percent (similar to ingestion) has been assumed Due
to the phy,icoch.Bical nature of dioxin. (high molecular weight and
low vapor pressure) it has been assumed that under normal use
condition, dioxin would not become airborne and thus inhaled.
Since the absorption efficiency for dermal exposure is significantly
lower than inge.tion, it is likely that chose papar productj| which ^
only touched by skin oil and which do not com. in direct contact with
food would have a lower risk. If the consumption, duration and/or
38
-------
frequency of use were also low, then the potential for exposure and
subsequent risk would be further reduced. If the product Is contacted
by an external phase such as water, skin oils, body fluids or edible
oils, th. matrix could absorb the fluid; swell and release the dioxin
for subsequent contact via the skin, membranes or via ingestion. AS
discussed in Section 3.2, if . product is coated or laminated, the
paper matrix has been assumed to be impervious to representative
external phases and, even for extended periods of contact time, is not
expected to result in an increased risk.
In terms of specific product categories which could potentially be
high-or-low risk, the following conclusions have been drawn (refer to
Table 4):
• Printing Papers:
- Coated ShB«r: Although the per capita consumption is high
and exposure to a single unit is repeated during the life of
a "page", the route is primarily dermal; furthermore, the
coating provides . barrier to potential matrix penetration
by skin oils. Therefore, this category comprises a low- risk
group.
- Unseated, h
mr: Although the exposure is mainly dermal,
there i. a subset of users who may also insert smaller
pieces of uncoated paper into the mouth for chewing,
spitting, or swallowing purposes. This user population
introduces a secondary ingestion- related risk. Since the
per capita consumption ranks second highest among the list
of categories (Table 3), its potential risk could not be
dismissed without further analysis.
Thin PflBftrii: The consumption is low/medium; exposure occurs
primarily by touching (dermal). The single exception is the
cigarette paper category but, as mentioned earlier,
39
-------
inhalation has not been addressed as a route of exposure.
Although the frequency of use may be high, each unit Is
generally used for a short period of time. Thus, this
category has been dismissed from further analysis.
Pleaded BrUmTi: The product use characterization Is
similar to that of thin papers, and the bleached Kraft
content is similar to uncoated sheets. Since the latter
category will be evaluated in further detail, these products
do not require additional scrutiny.
Packaging Papers:
Wrappings. Rag and ,^fiy SMpfftng; These three categories
do not appear to be high risk groups for three reasons:
consumption is relatively low; exposure is via dermal
contact since food packaging paper generally contacts dry
food; and since the glassine/greaseproof/vegetable parchment
papers that may contact wet or oily external phases are
coated, the potential risk via ingestion is minimized.
SBftcialtY P"Win: This category includes a variety of
end-user products such as' uncoated wrappers, doilies, gift
wrap, novelties and coffee filters. While the majority of
products represent exposure via dermal contact, one product
in particular, namely the coffee filter, involves direct
ingestion of the external phase (water). Total per capita
consumption is low; but frequency is medium-high. Also,
this single product is almost exclusively bleached Kraft
pulp. Due to the product use characterization parameters,
i.e., thorough contact and saturation with the extracting
medium during typical use, an analysis of exposure and risk
of coffee filters has been conducted.
40
-------
Tissue Papers:
r
These tissues have a medium level of
consumption but the duration of use is momentary. Moreover
user exposure is via skin contact. Although the bleached
Kraft content is high in these categories, the products
generally maintain their integrity during use, implying that
the matrix is not greatly affected by skin oils. Therefore,
these were not evaluated further.
Paper napkins, like tissues, also come in contact
with external skin and skin oils. However, unlike tissues
the use duration of a typical dinner napkin exceeds that of
a facial/toilet tissue. Assuming that skin oil penetration
in the matrix is a function of time, this category could
pose an increased risk. Therefor., it has been examined in
greater detail.
Ifiwfilling: Products in thi. category have varied uses which
could lead to a rang, of potential risks. The typical use
is for drying or wiping spills. Drying constitutes water
absorption into the paper; wiping Holies dermal contact
with skin oils. The absorbent nature of the products
introduces a third use, i..., greaae absorptlon during
microwave cooking. The consumption is medium, and the use
duration may be on the order of seconds or minutes.
However, th. pot.ntial risks du. to th. different external
phases Justify additional analysis.
Packaging Paperboard:
HliK C
rfr: There are three reasons that products in
this category may be of high-risk: consumption is medium,
use is for an extended duration, and exposure is via
ingestion of fluids contained within the cartons. However.
there is one overwhelming reason to dismiss this category.
41
-------
I.e., coatings. Since dairy and non-dairy (juice) carton
stock is laminated, the coating provides an effective
barrier for the paperboard matrix, thereby minimizing the
potential risk. One implicit assumption is that the
effectiveness of the coating is not time- dependent, i.e..
there is no penetration of the liquid into the matrix over
several days of contact time. This category has not been
further evaluated.
Pmr PlflrMflTHYi: The presence of laminations has
eliminated consideration of coated plates. For uncoated
Plates, consumption and duration are medium; exposure may
occur by touching the plat, surfaces or by inge.tion of food
that contacts the plate. Due to the potential range of
risks in this category, it has been evaluated further.
ftgfffl.tth; Consumption and use duration of uncoated
cups .re relatively low. Cups coated on the inside for
hot/cold beverages are analogous to the packaging paperboard
products: the coating has been assumed to eliminate the
potential exposure via ingestion. The exterior surfaces of
the cups, uncoated, are exposed to skin oils and dermal
contact. However. since the uncoated paper plates
constitute a similar exposure scenario, this category has
been exempted from a detailed analysis.
friable. Bftflrd. Linftrhoarda flnd r^dln* ^rr»nr 7^ ^
characterization, external phases and exposure route
features of products from these categories are all
considered in other product categories. Moreover.
consumption is low for ovenable board and linerboard.
Folding carton products are typically used for dry goods
storage such as medicines, cosmetics or prepared/packaged
food. Thus, the matrix is not penetrated by an external
fluid phase. Hence, these categories have not been
42
-------
considered for further evaluation.
Pulp:
Ptsppsabje
The product use parameters, i.e. high
frequency and per capita consumption, imply a high ejcposure
level. Although the mode of contact is dermal absorption
the extended duration for external phase saturation in the
pulp matrix may increase the potential dioxin availability
to a significant degree. Accordingly, this category has
required further analysis.
Feminine HYy1fne
sanltary napkin produ
-------
o dinner napkin,
o paper towel,
• coffee filter, and
• uncoated free sheet.
3-3-2 Estimate of Potantt^ P1ftfftn
Assuming a dioxin concentration level of 10 ppt or 10 pg/gm of
bleached Kraft fiber, the amount of dioxin mass available for exposure
can be calculated for a prototypical product as a function of several
estimated factors which include the following: MSs of the unit
product, surface area contacted, external phase penetration in the
matrix and fraction of the external phase ingested or absorbed. For
the seven products representing potential high-risk categories, the
total dioxin mass available for exposure following a typical use
situation is summarized in Table 7. The methodology for estimating
the potential exposure levels is outlined in this section.
Column (A) of Table 7 list, the seven sample products and their
associated bleached Kraft content. Although the primary component in
each product i, bleached Kraft fiber, the actual fraction ranges from
60 to 100 percent, appending on the quantity of other components such
as fillers or resin.. Also it i. important to not. that for three
product, (th. uncoated paper plate, paper towel, and uncoated sheet)
multiple u.. situation, have been postulated. Each use effectively
result, in a different potential exposure level. !„ subsequent
analyst., only th. highest exposure level i. considered. For the
remaining product., a single us. situation adequately defines the
potential dioxin mas. to which a user could be exposed.
Although the dioxin concentration in bleached Kraft fiber has baen
assumed to be constant, the amount of dioxin in each product varies
with the mass of bleached Kraft fiber in a product unit. Column (B)
presents the mass of each prototypical unit as measured during this
44
-------
TABLE 7
Ul
PRODUCT
PERCENT
BK/UNIT
(A)
UNCOATED
PAPER
PLATE
90.0
DISPOSABLE
DIAPER
60.0
SANITARY
TAMPON
95.0
DINNER
NAPKIN
98.0
PAPER
TOWEL
95.0
COFFEE
FILTER
100.0
UNCOATED
SHEET (L)
90.0
ESTIMATES OF POTENT]
UNIT EST.
MASS DIOXIN
WT/UNIT
(CM) (PC)
(C)
16.5 148.5
70.0 420.0
2.5 23.8
9.5 93.1
3.2 30.4
6.3 63.0
4.0 36.0
0.04 0.4
iAL DIOXIN EXPOSURE LEVELS BASED ON UNIT CONSUMPTION
PRODUCT
SURF
AREA
324.0
826.0
16.1
1865.0
671.0
881.0
603.0
1.6
UUNIAINIHU
BLEACHED
FOR A TYPICAL
EXTERNAL
PHASE
(EP)
SKIN OIL
OILS
URINE
BLOOD
SKIN OIL
SKIN OIL
WATER
OILS
WATER
SKIN OIL
SALIVA
EXPOSURE
TIME
(F)
30 MIN
30 MIN
4 HRS
4 HRS
30 MIN
15 SEC
15 SEC
3 MIN
5 MIN
15 SEC
30 SEC
i KRAFT (BK)
USE SITUATION
CONTACT
AREA
PERCENT
(C)
23
16
60
100
80
100
100
100
100
10
100
DEPTH
PENETRN
FRACTION
(H)
0.01
0.50
1.00
0.50
0.01
0.01
1.00
1.00
1.00
0.005
1.00
DIOX MASS
IN EP VOL
CONTACTED
(I)
0.3
11.9
252.0
11.9
0.7
0.3
30.4
30.4
63.0
0.01
0.4
-----...
EP
EXPOSURE
PERCENT
(J)
0.1
25.0
5.0
10.0
0.1
0.1
0.1
1.0
99.0
0.1
95.0
DIOX MASS
AVAILABLE
FOR EXPOSURE
(PC/UNIT)
|K /
3.4E-04
3.0E+00
1.3E+01
1.2E+00
7.4E-04
3.0E-04
3.0E-02
3.0E-01
6.2E+01
l.OE-05
3.4E-01
-------
NOTES FOR TABLE 7:
SSI S^Kfiyr^S^SIM^^
c-
D. BASED OH ADL ESTIIUTED VALUES AND MEASUREMENTS .
B. SEE TOT RK DISCUSSION OH EXTERNAL PHASE UNITATIONS.
t. EXPOSURE TIME IS BASED OH ADL ESTIMATE OF TYPICAL PRODUCT USE
.
,v
>Y
™E
J- PHASE
K. BASED ON THE TOTAL MASS OF DIOXIN IN A PRODUCT AND
-------
analysis. The product of the percent bleached Kraft, unit mass and
10 ppt concentration, as shown in Column <«. provides the estimated
dioxin mass per unit.
Based on the physical geometry, a single surface area for each product
is calculated and summarized in Column (D). The specific dimensions
and geometric assumptions are discussed on a p.r-product basis later
in this section.
The characterization of a typical use situation is defined in Columns
(E) through (H). The primary external phase, as shown in the Column
(E). may be water or a water-based solvent, skin oil, edible oil such
as hamburger or bacon grease, or body fluid such as saliva, blood or
urine. As discussed in Section 3, the quantity of dioxin solubilized
is not a function of the solvent type since it ha. been assumed that
dissolution is not limited by solubility. Inatead, the differences
among the solvent, represent the relative ease with which a pulp/paper
matrix could be penetrated, so that the dioxin could become available
for exposure. For example, the relative volume of skin oil that
touches a sheet of paper is much less than the volume of urine that is
absorbed in a diaper. Accordingly, the amount of bleached Kraft fiber
penetrated by the external phase varie. between the two products
Although the exact volumes of 'each external phase for all the
scenario, have not been quantified, the differences in matrix
penetration are accounted for using factors defined in Columns (E)
through (H).
The exposure time, .8 ilsted ln column (F), is not used in the actual
calculation scheme; however, it provide, a basis for a reasonable
estimate of the contact area percent and depth penetration fraction
which are tabulated in the two column, immediately following For
several product, and uses, it would be unrealistic to assume that an
external phase contacts the entire volume of bleached Kraft fiber and
saturates the entire matrix. If that were the case, then every
occurrence of touching a page would result in a soggy sheet with none
47
-------
of its initial integrity. In fact, only a portion of the surface is
contacted, and only a fraction of the depth is penetrated by the
external phase in most instances. Only in a few select cases does the
entire product volume (area x depth) encounter a volume of external
Phase. The estimated available dioxin per unit has been adjusted
accordingly for each product and summarized in Column (I) .
Of the total external phase chat is absorbed into the matrix, there is
always some fraction that remains in the web. Th. portion in direct
contact with the user accounts for the fraction of dioxin that is
potentially available. This exposure percent is listed in Column (J)
For example, given the total volume of urine in a diaper it is
estimated that about five percent comes in direct contact with the
infant's skin surface. On the other hand, about ninety nine percent
of the water passing through a coffee filter i. recovered and
subsequently ingested. Assuming the dioxin ha. been removed from the
matrix and solubilized in the external phas., a larger fraction of the
dioxin mass in the water is available for exposure than the aass in
the urine.
The last Column (K) contains the actual mass of dioxin that is
potentially available for ingestion or dermal absorption. In summary
the total estimated dioxin mass in'-th. product unit has been reduced
first by the fractional volume of product contacted, then further
attenuated by the portion of external phase exposed to the user In
the disc«.sion that follow,, the dimension, of each product and
assumption, of usage are outlined.
Pflpftr Plnrti: A sample eight- inch dinner plate weighs
16.5 gas, and the surface area of one face is 324 sq cm. The two
specific use .cenario. considered are (i) holding the plate, and
(ii) eacing a hamburger which is on the plate. Note that no
cumulative effects will be considered in this analysis.
48
-------
For the first situation, assume a one-Inch annular ring is
touched for about half an hour; therefore, skin oil encounters
about 23% of the total available surface area. For typical skin
011-matrix contact scenarios, assume a one-percent penetration
into the depth of the plate surface. Of the total volume of skin
oil that enters the paper web. a small fraction of a percent
returns to the user. This assumption has been maintained for
other products where the typical use Involve, dermal contact/skin
oil. Given this use situation, of the total dioxin mass of 148.5
pg. about 3.4 x 10- pg has been calculated to be available to
the user.
The second scenario assumes a four- inch hamburger eaten from a
paper plate. Hamburger oil covers about 16% of the top surface
and penetrates about half the depth of the plate. About one
fourth of the oil that contacts the pl.te is removed with the
burger and ..ten. In this ca.e, 3.0 pg of the total 148.5 pg has
been assumed to be available for exposure.
Although the weight of a diaper (70 g) is
high compared to other paper products, its bleached Kraft content
is only 60%. The remainder is fillers, plastic lining, tape
•tc. A st«dard absorbent diaper, when spread open, measures
•bout 8 in wide and 16 in long. The resultant surface area is
826 sq cm. The external phase 1. urine, which may have contact
with the diaper over several hours. About 60% of a diaper
surface 1, generally wet, and it is reasonable to assume that the
entire depth of the diaper i, saturated. The extended period of
u,. allow, for repeated contact with urine; therefore, It has
been estimated that the infant is exposed to about 5 percent of
the volume.
Given these us. conditions, an Initial dioxin content of 420 "'pg
per diaper is reduced to 13.0 pg available for exposure.
49
-------
This product consists primarily of bleached
Kraft pulp. Its mass (including the string, but not the outer
cardboard liner) is about 2.5 g. The geometry of a compressed
tampon is a solid cylinder with an outer area of 16.1 sq cm.
Over a period of 4 hours, blood, the external phase, is in
contact with the entire outer surface and is generally absorbed
through half the tampon thickness. About one- tenth of this
external phase may come in contact with the inner mucous
membranes. Applying these assumptions, a total mass of 23.8 pg
dioxin per tampon has been reduced to 1.2 pg available for
exposure .
Ptnner papMn: This paper producc haa
resin content. A typical napkin, 17 in. square, weighs about 9.5
gms and has a single surface area of 1865 sq cm. For a half-hour
use time, skin oils touch about 80 percent of the total surface.
As with the uncoated plate, the depth penetration is estimated to
be 1 percent and 0.1 percent of the skin oil remains on the skin
surface of the user. For this scenario, 93.1 pg of dioxin in the
product have been reduced to 7.4 x lO'4 pg available to the user.
faper Tgve.1; The presence of wet strength resins reduces the
bleached Kraft content slightly for this product. A typical
single unit has dimensions of 11.25 in x 9.25 in, resulting in an
available surface area of 671 sq cm. The potential use scenarios
which have been postulated to illustrate the range of results
are: (1) wiping up a spill, (2) drying hands, and (3) using the
towel for bacon grease absorption during microwave cooking.
Th« first use situation involves skin contact for a short period
of time. Essentially, an entire surface is touched, and depth
penetration is 1 percent, as assumed earlier. Less than 1
percent of the skin oil re-contacts the user; thus 30.4 pg in £he
product has been reduced to 3.0 x 10'4 pg available for the user.
50
-------
The second scenario postulates water as the external phase.
Although the use duration is short, the total area and depth are
saturated with water. Since the function of the product is to
dry, a fraction of a percent of water returns to the user In
this case, 3.0 x 10'2 pg of dioxin hav. been assumed to be
potentially available.
The third us. situation involves edible oils. namely bacon
grease, as the external phase. In the three-minute cooking time.
the entire paper towel is saturated with the grease and about 1
percent remains on the bacon strips to be eaten. For this
example, the dioxin mass calculated to be available is the
highest of the three scenarios: 0.30 pg from the initial 30.4
PS-
frf-fte "inn Of the seven selected products, this is the only
example of 100 percent bleached Kraft content. A medium-sized
filter, 11 3/8 in x 12 in, with a surface area of 881 sq cm
weighs about 6.3 gms. in a five-minute period of use, hot water
literally acts as an extracting solvent, contacting 100 percent
of the area and depth of the filter. The bulk of the water is
recovered a. coffee, and only about 1 percent is retained on the
wet filter. For this product, 62 of the total 63 pg have been
assumed to be available for exposure.
Vncoated iffiMr; This product, which contains about 90 percent
bleached Kraft, can have two very different use situations. The
first involves routine touching or handling of sheets/pages; the
second' scenario involve, chewing of paper fragments which may be
followed by ingestion or expectoration.
A typical sheet, 8.5 in x 11 in. has a surface area of about 103
sq cm. For reading/writing applications, skin oil touches the
sheet for about 15 sec, and generally is in contact with about 10
percent of the area. Due to the momentary nature of use, the
51
-------
assumed depth penetration Is less than I percent. Accordingly,
the 36 pg of dioxin In the sheet of paper has been reduced to 1.0
x 10 pg available for user exposure.
A fractional piece of a sheet of paper used for a spitball. on
the other hand, constitutes a potential ingestion exposure. A
half-inch square piece of paper weighing 0.04 ga has a single
surface area of 1.6 sq cm. Given 30 second, in the mouth, the
wad of paper is totally surrounded on .11 sides by saliva the
external phase. Of the total external phase contacting the paper
mass, a major fraction, about 95 percent ..y be ingested - the
remainder leaves with the paper. Thus, the total mass of dioxin
0.4 pg have been slightly reduced to 0.34 pg available for user
exposure.
4.0 RISK ASSESSMPMT
The process of risk assessment for exposure to dioxin contained in
bleached Kraft paper products involve, estimating average lifetime
daily exposure to dioxin. the efficiency of the exposure route in
absorbing dioxin, the estimated seventy-year lifetime use pattern of
the product and the average weight of the product user to calculate
the average lifetime daily dose per kilogram of body weight (U.S. EPA.
1984a, Eschenroeder. et al., 1986).
The dose is tran.l.t.d into risk by applying a potency factor or unit
risk multiplier *lch yields an estimate of the increased lifetime
cancer riak due to the particular exposure scenario.
4-1
Exposure^
For each type of paper product scenarios have been quantified and are
outlined in Table 8. Column B in Table 8 wa. previously generated in
52
-------
TABLE 8
UNIT
DIOXIN
DIOXIN NO. OF
U)
UNCOATED 3.0E-09
PAPER
PLATE
Sffi"" »-3E-08
?»" l"-<"
DINNER 7.4E-13
NAPKIN
PAPER 3 OE-10
TOWEL
COFFEE
FILTER
6.2E-08
UNCOATED 1 OE-14
SHEET 3.4E-10
50 1.5E-09
1.5 1.9E-10
50 5.9E-10
1.5 1.1E-14
50 1.5E-10
50 3.1E-08
1.5 1.5E-16
50 1.7E-10
1 1.5E-09
3 3.4E-14
2 3.0E-10
1 3.1E-08
1000 1.5E-13
5 8.6E-10
as™ spisT ilsiTi"'
^INC ESffiF SPSS1
70 2.1E-11
6 1.1E-09 10.2 1.1E-10
i
t 5.9E-10 60 9.8E-12
70 4.8E-16
70 4.3E-12
70 4.5E-10
60 2.5E-15
3^.8 2.5E-11
70
50
(J)
2. IE- 11 6.6E-06
3 4.8E-12 1.5E-06
40 5.6E-12 1.8E-06
70 4.BE-16 1.5E-10
70 4.3E-12 1.4E-06
3.2E-10 1.0E-04
50 1.8E-15 5.6E-10
9 3.2E-12 9.8E-07
-------
NOTES & ASSUMPTIONS FOR TABLE 8:
A- £25 oSSS^n1?11! 9N PROTOTYPICAL PAPER PRODUCT DIMENSIONS
c
INTERNAL CONTACT 50 PER CENT
INGESTION SO PER CENT
° ABSORPTION EFFICIENCY!1" °F PR°DUCT REFLECTS ™E «™CTI« DUE TO THE
E. THE NUMBER OF UNITS USED PER DAY ASSUMES A TYPICAL USER OF THAT PRODUCT.
F. THE DIOXIN DOSE PER DAY - DOSE/UNIT X NO.OF UNITS USED/DAY
Ul
*" H
•• • »•••* vawn AM uudn uun. mm* i np. n^w ftftf • im • c TUP iv« «* «• IVlCP
C. THE AVERACETWEIGHT OF THE TYPICAL USER IS INPUT ON THE FOLLOWING BASIS:
ADULT FEMALE 60 KG
CHILD UNDER 18 3.14 + (3.52 X MEDIAN AGE)
J.
K- EXroSURE^^THFMmllJL^^^^IS^FSSeyCT OF THE LIFETIME
-------
Table 7 and indicates the mass of dioxin (converted from pg to o,g)
which is ingested or contacted. The following sections address each
product and discuss how this dioxin exposure estimate has been
translated into an average lifetime daily dose.
4-l-l Uncoacsd
This potential exposure scenario for use of uncoated paper plates
involves ingestion of dioxin in food oils, it ha. been assumed that
50 percent of the ingested dioxin is absorbed by this route
(McConnell, et al., 1984). that one uncoated paper plate is used each
day and that the duration of paper plat, use Uses for a 70 year
lifetime. It ha. also been assumed that the user ha. an average adult
-ale weight of 70 kilograms and that the av.r.g. lifetime daily dose
is equal to the dose per day during use. A, .hown ln Column , of
Table . «. a lifetime dioxin dose for u.. of uncoated paper platM of
2.1 x 10 milligram, per kilogra. body weight per day (»gAg/day)
has been esti
has been estimated.
4.1.2.
This potential exposure scenario for use of disposable diapers
involves skin contact with dioxin in urine. It has been assumed that
1.5 percent of the contacted dioxin i, absorbed by thi. route (Poiger
and SchUtter, 1980), that six disposable diapers are used each day
and that the duration of diaper us. lasts for three years. It has
also been as.umed that the user ha. an average weight of 10 2
kilogram and that the average lifetime daily dose is equal to the
dose p.r day during u.. multiplied by the fraction of a 70 year
lifetim. during which the product i. used. A. shown in Column J of
Tabl.^8. . lifetime dioxin dose for u.. of disposable diapers of 4 8 x
10 milligram, per kilogram body weight per day (mgAg/day) has
been estimated.
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• 1 • 3 Sanitary Tanraon
This potential exposure scenario for use of sanitary tampons Involves
mucous membrane contact with dioxin in blood. It has been assumed
that 50 percent of the contacted dioxin is absorbed by this route (ADL
estimate). It has also been assumed that thirty sanitary tampons are
used each month, representing an annual daily use of on. tampon per
day; the duration of sanitary tampon use has been assumed to be 40
years. The user has an assumed average weight of 60 kilograms and the
average lifetime daily dose is equal to the dose per day during use
multiplied by the fraction of a 70 year lifetime during which the
product is used. As shown in Column J of Table 8, a lifetime dioxin
exposure for use of sanitary tampons of 5.6 x 10'12 milligrams per
kilogram body weight per day (mg/kg/day) has been estimated.
• 1.4 Dinner
This potential exposure scenario for use of dinner napkins involves
skin contact with dioxin in skin oil. It has been assumed that 1 5
percent of the contacted dioxin is absorbed by this route (Polger and
Schlatter, 1980), that thr.e dinner napkins are used each day and that
the duration of napkin us. lasts for 70 years. It has also been
assumed that the user has an average weight of 70 kilograms and that
the average lifetime daily dose is equal to the dose per day during
use multiplied by the fraction of a 70 year lif.tlm. during which the
product i. used. A. shown in Column J of Table 8, a lifetime dioxin
exposure for users of dinner napkins of 4.8 x 10'16 milligrams per
kilogram body weight per day (mgAg/day) has been estimated.
4.1.5 Pacer Towel
This potential exposure scenario for us. of paper towels in microwave
cooking involves inge.tion of dioxin in food oils. It has be'en
assumed that 50 percent of the contacted dioxin is absorbed by this
rout. (McConn.ll, .t al., 1984), that two paper towels are used each
day and that the duration of towel use lasts for 70 years. It has
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also been assum.d that the user has an average weight of 70
kilograms and that the average lifetime daily dose is equal to the
dose per day during use multiplied by the fraction of a 70 year
lifetime during which the product is used. As shown in Column J of
Table 8, a lifetime dioxln exposure for users of paper towels of a 3 x
10 milligrams per kilogram body weight per day (mg/lcg/day) has ben
estimated.
Coffee Filter
This potential exposure scenario for use of coffee filters involves
inges-tion of dioxin in coffee. It has been assumed that 50 percent of
the contacted dioxin is absorbed by this route (McConn.il, et al
1984), that one coffee filter is used each day and that the duration
of coffee filter use lasts for 50 years. It has also been assumed
that the user has an average weight of 70 kilograms and that the
average lifetime daily dose is equal to the dose par day during us.
-ultipled by the fraction of a 70 year lifetime during which the
product is used. AS shown in Column J of Table 8, a lif.tim. dioxin
exposure for users of coffe. filters of 3.2 x 10'10 milligrams per
kilogram body weight per day (mgAg/day) has been estimated.
4.1.7 Uneoated
This potential exposure scenario for us. of uncoated sheet involves
skin contact with dioxin in skin oil. Ic has been assumed that 1 5
percent of the contacted dioxin is absorbed by this route (Poiger &
Schl.tt.r, 1980), that 1000 uncoated sheets are used each day and that
the duration of this intensive us. of uncoated sheet lasts for 50
years. It has also been assumed that th. user ha. an average weight
of 60 kilograms and that the average lif.tim. daily dose is equal to
the dos. p.r day during us. multilpll.d by th. fraction of a 70 year
lif.tim. during which th. product is us.d. AS shown in Column J "of
Tabl. 8. a lif.tim. dioxin .xposur. for int.nslv. us. of uncoated
sheet of 1.8 x ID' milligrams per kilogram body waight p.r day
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(mgAg/day) has been estimated.
4-l-« Unseated sheet
This potential exposure scenario for use of uncoated sheet involves
ingestion of dioxin in saliva or in the paper itself. It has been
assumed that 50 percent of the contacted dioxin is absorbed by this
route (McConn.ll, et. al., 1984), that five fragments of uncoated
sheet are used in this manner, each day, and that the duration of this
type of paper use last, for 9 years. It has also been assumed that
the user has an average weight of 34.8 kilograms and that the average
lifetime daily dose Is equal to the dose per day during use multiplied
by the fraction of a 70 year lifetime during which the product is
used. As shown in Column J of Table 8, a lifeci«i dioxin exposure for
this type of use of unco.ted sheet of 3.2 x 10'12 milligrams per
kilogram body weight per day (mgAg/day) has been estimated.
Risk EgPimarion
The U.S. Environmental Protection Agency (EPA) has calculated an upper
95% confidence limit of the carcinogenic potency of 2,3,7,8-TCDD which
Is equal to 1.6 x 10 per mgAg/day of exposure (USEPA, 1984a, 1985).
Since this potency factor is based upon the administered dose it is
multiplied by 2 to give a potency of 3.1 x 105 per mgAg/day of
absorbed dose (U.S. EPA. 1984b, Eschenroeder. et .1., 1986). The EPA
has also developed procedure, for estimating risks associated with
mixture, of .pacific i.omer, of dioxin. and furans; however, for this
risk calculation it ha. been ...umed that all of the contaminants are
equivalent to 2,3,7,8-TCDD (USEPA, 1987).
The upper 95% confidence limit of exc.s. cancer risk resulting from
the dioxin dose 1, calculated by multiplying the absorbed potency
factor of 3.1 x 10 (mgAg/day)'l by the average daily lifetime
dose expressed as mgAg/day to yield a unities, expression of
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individual excess risk. When multiplied by the size of a user
population, this individual risk yields the expected number of excess
cancers which will result over the lifetime of the population as a
result of the exposure. An estimate of the annual number of excess
cancers to be expected in the population can be obtained by dividing
by the 70 year average lifetime.
Column K of Table 8 provides the estimated lifetime cancer risks for
an individual product user. Demographic data can b. used to evaluate
population-based risks (e.g., user population data in Table 3).
Overall, these individual risk estimates range from 1.5 x 10'10 for
dinner napkin, to 1.0 x 10*4 for coffee filter.. Coffee filters are
the only product category which results in a risk greater than the
conventional benchmark of 10'5. Using 10'6 a. the cut-off, four other
products are included: uncoated paper pl.tes, disposable diapers,
sanitary tampons and paper towels.
5.0 DISCUSSION
In this section the -sumption, underlying the analysi. have been
summarized and the result, and th.i* implication, have been discussed
Recommendations for additional work which may reduc. some of the
uncertainty associated with thi. preliminary study have elso been
provided.
5-l UncertaintyM *** A.11wr1
Throughout thi, ,tudy a,,u»ption, have been Mde. m some cases EPA
report, or .cientific literature have been u..d to .upport these
assumption,. Where such support wa, lacking or unavailable, estimates
have been made using p.se experience and Judgment. For example, In
the absence of data, important assumption, have been made about:
59
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o potential levels of dioxln contaalnatlon,
• the surface area of product contacted,
• the depth of penetration of the external phase,
• the availability of dioxin to the external phase,
• the extent of absorption or ingestion of external phase, and
• the duration and frequency of product
use.
Accepting the assumption that consumers may be exposed to dioxin
through us. of paper products, a rationale by which such exposure
could occur has been developed. The scenario, ar. reasonable and are
in accord with current understanding of the chemical and physical
behavior of dioxin; however, there is in.uffici.nt information to
estimate the magnitude of the uncertainty.
In addition to the uncertainty inherent in the evaluation of the
potential for exposure, there also exists substantial uncertainty in
the calculation of carcinogenic potency factors. The final
uncertainty associated with this analysis would thus be the product of
the uncertainty In the exposure estimates and the uncertainty in the
risk factor.
5-2 Implication* of t*.
The result. pr...nt.d in Table 8 imply that md,r certain
circx».t««:.. bl.Mh.d fcmfe product „,.„ My be ^^ ^ ^^
and, under the definition of zero thre.hold risk and using the
assumption. o«tlln.d in this report, will have a calculable lifetime
risk of cancer.
Although the risk, calculated in this study are relatively low.
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ranging approximately from lO'4 to 10'10. they are totally dependent
on the assumptions of the exposure scenarios. In the actual
population of product users, there may be group, who us. products more
or less intensively than has been assumed and, thus, have higher or
lower risks. Furthermore, the combined risk from using several
bleached Kraft paper products has not been considered.
Potential contamination of consumer paper product, with dioxin raises
questions about the impact of that contamination on emissions from
municipal solid waste (MSW) incinerators. A complete summary of the
literature on dioxin emissions from incinerator., dioxin content in
waste feed streams and generation of dioxin during the combustion
process is beyond the scope of this exposure and risk assessment
However, several observations can be made, and these have been
outlined below.
During the 1970's and 1980's, dioxins and furan. were identified in
precipitator fly ash samples fro. MSW incinerators in the U S
Canada. Europe and Asia. The rn.ctumi.rn of formation of dioxins and
furans ha, been studied extensively, but the relationship between
dioxin/furan emission, and the type of waste incinerated is still
controversial. There are essentially no data to confirm that
dioxins/furans In the wast, f..d'- material, result in dioxin/furan
emission,. Generation of dioxins/furan, a. product, of incomplete
co«bu.tion appear, to be more closely correlated with facility
operating condition, and with the availability of precursors such as
organochlorine compound, and po.sibly inorganic chlorine.
Paper i. a Mjor fraction of the wa.t. stream, of typical MSW
incinerator.. Domalski, et .1. (1986) reported that paper represented
approximately 50% of the ma,, of the MSW at a Brooklyn. N.w York
facility during 8ne week in early 1984; 42.5% w.. unbleached paper and
4.6% wa, bleached paper. Ac a Baltimore County, Maryland, facility.
approximately 60% of the waste stream during a week in early 1983 was
classified as paper materials. The amount, of chlorine contributed by
MSW component, at the two facilitie. were also determined. The major
61
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amounts of chlorine in MSW were contained in the paper and plastic
fractions.
The paper fractions contained approximately one-quarter to one-half of
the weekly average total chlorine content (0.45 - 0.89% mass)
One-third to two-thirds of the total chlorine content in pap.r was
determined to be water-soluble chlorine which is more likely to
represent inorganic materials. On the other hand, greater than 90% of
the chlorine in the plastic fraction was water-insoluble chlorine
compounds.
Although paper is a major portion of typical MSW feed streams and may
represent a source of chlorine, there is no evidence linking increased
paper content in MSW to increased dioxin emissions fro. an MSW
incinerator or documenting that dioxin in a waste stream would be
likely to survive the combustion process.
Another important implication of the results is that they may be used
as a basis for regulation or legal action, or they may unduly alarm
the public. It cannot be stated too strongly that these results have
been based on numerous assumptions and are intended to guide EPA
planning for data collection and relevant research studies The
following section identifies some areas where additional research may
help to resolve some of the uncertainty surrounding this subject.
5.3
In order to resolve some of the uncertainty regarding the potential
for exposure to dioxin in bleached Kraft paper products, several areas
where information is particularly lacking or where there are
significant uncertainties have been identifi.d. For example
additional data are needed on how dioxin may be generated in the
bleached Kraft process, on the relative levels of dioxin in bl.ache'd
and semi-bleached Kraft product and on the dioxin content of consumer
products.
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There are some fundamental questions regarding the physical
distribution of dioxin contamination in the paper matrix. For
example, is dioxin incorporated or bonded into the paper matrix, is it
adsorbed to the surface of the matrix, or is it free within the paper
as has been assumed in foregoing analysis?
Another fundamental area of uncertainty concern, the migration of
chemicals at very low (ppt) concentrations. Dioxin at 10 ppt may have
such a low migration rate that exposures, under normal scenario, will
not occur. Finally, it has been assumed that conventional coatings
act as a barrier and prevent exposure. One could also hypothesize
mechanisms by which the dioxin would be concentrated in the coating.
Another area which is important for accurate risJc assessment is
determination of usage pattern, for consumers of p.p.r products.
Marketing data, consumer survey,, and focu, group, could be used to
develop a better understanding of the extent of exposure, in terms of
both frequency and duration, and of the nature of any high risk user *
populations such a, children or user, of multiple type, of bleached
Kraft products.
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REFERENCES
1. Adams. W. and K.M. Blaine. 1986. A water solubility
determination of 2.3,7,8-TCDD. Chejnosphere 15 (9-12): 1397-1400.
2. American Paper Institute. 1986. Statistics of Paper, Pap.rboard
and Word Pulp Data Thru 1985. New York.
3. Domalski, E.S.; K.L. Churney; A.E. Ledford, Jr. and S.S. Bruce.
1986. Monitoring the fate of chlorine from MSW sampling through
combustion. Part 1: Analysis of the waste stream for chlorine.
Chemosphere 15(9-12): 1339-1354.
4. Eschenroeder, A., R.J. Jaeger, J.J. Ospital and C.P. Doyle.
1986. Health risk analysis of human exposures to soil amended
with sewage sludge contaminated with polychlorinated
dibenzodioxins and dibenzofurans. Vet. and Human Tox. 28(5)-
435 - 442.
5. F.landysz, J. and Z. Canowiak. 1982. Sources of contamination
of food with polychlorinated biphenyls (PCB). (Polish)
Bromatologia i Chemia Toksykologiczna 15 (3), 161-166.
6. Freeman, R.A. and J.M. Schroy. 1986. Modeling the transport of
2,3,7,8-TCDD and other low volatility chemicals in soils.
Environ. Prog. 5(1): 28-33.
7. Freeman, R.A. and J.M. Schroy. 1985. Environmental mobility of
TCDD. Chemosphere 14 (6/7): 873-876.
8. Hotchkiss, J.H. and A.J. Vecchio. 1983. Analysis of direct
contact paper and paperboard food packaging for N-nitrosomor-
pholine and morpholine. J. Food Sci. 48: 240-242.
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REFERENCES
9. laccarino, T. . L. Croci. S. Gizzarelli, A. Fcrrara, G. DeFellp
and M. Morgantini. 1982. Precise definition of microbial tests
on migration of antiseptics from food wrapping paper. (Italian)
Bullettino dei Chimici dell'Unione Italian* dei Laboratori
Provincial! 33 (S6), pp 629-637.
LO. Mackay, D, S. Paterson and B. Cheung. 1985. Evaluating the
environmental fate of chemicals. The fugacity level III approach
as applied to 2.3.7.8-TCDD. Chemosphere 14 (6/7): 859-863.
11. Marple, L., B. Berridge and L.Throop. 1986. Measurement of the
Water-octanol partition coefficient of 2,3,7,8-t.trachloro-
diBenzo-p-dioxin. Environ. Sci. Technol. 20(4): 397-399.
12. McConnell, E.. G. Lucier, R. Rumbaugh, et al. 1984. Dioxin in
soil: Unavailability after ingestion by rats and guinea pigs.
Science. March 9.
13. National Center for Health Statistics. 1986. Aging in the
Eighties, Prevalence and Impact of Urinary Problems in
Individual, Age 65 Years and Over. Advance Data from Vital and
Health Statistics. No. 121. DHHS Pub. No. (PHS) 86 . 1250.
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dioxin: rate, of volatilization and photolysis in the
environment. Environ. Sci. Technol. 20(5): 490-492.
15. Polgor, H. and C. Schlatt.r. 1980. Influence of solvents and
adsorbents on dermal and intestinal absorption of TCDD. Food
Cosmet. Toxicol. 18(5): 477-481.
16. Predicast Forecast: Paper, Paperboard and Pulp. 1985. p. B-183
thru B-192.
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REFERENCES
17. Schroy, J.M., F.D. Hileman and S.C. Cheng. 1985. Physical/
chemical properties of 2,3,7,8-TCDD. Chemosphere 14 (6/7)-
877-880.
18. Sen, N.P. and P.A. Baddoo. 1986. Origin of N-nitrosomorpholine
contamination in margarine. J. Food Sci., 51 (1): 216-217.
19. Stanovick, R.P., S.I. Shahied and E. Missaghi. 1973.
Determination of polychlorinated biphenyl (Aroclor 1242)
migration into food types. Bulletin of Envir. Contain, and Tox
10 (2): 101-107.
20. Till, D.E., D.J. Ehntholt, A.D. Schwope, K.R. Sidman, RH
Whelan and R.C. Reid. 1983. A study of indirect food additive
migration. Arthur D. Little, Inc. report to Department of Health
and Human Services, Public Health Service, Food and Drug
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21. U.S. Bureau of the Census. 1987. Statistical Abstract of the
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22. U.S. Department of Commerce. 1987. Paper and Allied Products,
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23. U.S. Dep.rtm.nt of Commerc., Bureau of the Census. 1985.
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24. U.S. Environmental Protection Agency. 1987. interim Procedures
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CDFs). EPA/625/3-87/012.
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REFERENCES
25. U.S. Environmental Protection Agency. 1985. Health Risk
Assessment Approach for 2,3,7,8-TCDD. EPA/600-8-85/013.
26. U.S. Environmental Protection Agency. 1984a. Ambient Water
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