ESTIMATED WORKER EXPOSURE
TO 2378 TCDD AND 2378 TCDF
IN THE MANUFACTURE, PROCESSING, AND
COMMERCIAL USE OF PULP, PAPER,
AND PAPER PRODUCTS
PEI Associates, Inc.
11499 Chester Road
Cincinnati, Ohio 45246
Contract No. 68-D8-0112
Work Assignment No. P2-2
PN 3786-26
for
U.S. ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF TOXIC SUBSTANCES
401 M STREET, S.W.
WASHINGTON, D.C. 20460
March 1990
-------
EPA 560/4-90-015
July 1990
ESTIMATED WORKER EXPOSURE TO 2378 TCDD
AND 2378 TCDF IN THE MANUFACTURE, PROCESSING,
AND COMMERCIAL USE OF PULP, PAPER, AND
PAPER PRODUCTS
by
Radha Krishnan, Chris Meyer, Bob Goodman,
Mary Beth Foerst
Contract No. 68-D8-0112
Work Assignment No. P2-2
PN 3786-26
U.S. ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF TOXIC SUBSTANCES
401 M STREET, S.W.
WASHINGTON, D.C. 20460
-------
DISCLAIMER
This document has been reviewed and approved for publication by the Office of Toxic
Substances, Office of Pesticides and Toxic Substances, U.S. Environmental Protection Agency. The
use of trade names or commercial products does not constitute Agency endorsement or
recommendation for use.
-------
ACKNOWLEDGEMENTS
This report was prepared by PEI Associates, Inc. of Cincinnati, Ohio for the U.S.
Environmental Protection Agency's Office of Toxic Substances (OTS) under EPA Contract No.
68-D8-0112, Work Assignment Nos. Pl-20 and P2-2. The OTS Task Managers, George Heath and
Nhan Nguyen, and Ward Penberthy of OTS provided overall guidance in this effort. The PEI
Program Manager was Tom Corwin, and The Task Manager was Radha Krishnan, P.E. The
principal authors of the report were Radha Krishnan, Bob Goodman, Chris Meyer and Mary Beth
Foerst. The comments provided by the following individuals during the preparation of the report
are gratefully acknowledged: Mike Babich of the Consumer Products Safety Commission (CPSC);
Bob Fisher of the National Council of the Paper Industry for Air and Stream Improvement
(NCASI); and Claire Sullivan of the United Paperworkers International Union (UPIU).
-------
CONTENTS
Figures iii
Tables v
1. Introduction 1-1
2. Industry Profile 2-1
2.1 Pulp and papermaking operations 2-1
2.2 Dioxin formation in pulp and paper mills 2-14
2.3 Pulp and paper industry workforce characterization 2-24
3. Worker Exposure 3-1
3.1 Potential for worker exposure 3-2
3.2 Personal protective equipment 3-75
3.3 Method of absorption/inhalation 3-75
4. Conclusions and Recommendations 4-1
References R-l
Appendix A 104-Mill Study: 2378 TCDD and 2378 TCDF Concentra-
tions in Bleached Pulp on a Dry Basis A-l
Appendix B Risk Assessment Methodology B-l
ii
-------
FIGURES
Number Page
2-1 Typical Pulp and Paper Mill 2-4
2-2 Typical Four-Stage Bleach Process 2-7
2-3 Typical Papermaking Process 2-11
TABLES
Number Page
2-1 Abbreviations Used to Designate Bleaching Sequences 2-8
2-2 Effect of Defoamer Addition to Brownstock Kraft Pulp on
Subsequent Dioxin Formation During the Bleaching Process 2-17
2-3 Summary of TEQ and Corresponding 2378 TCDD and 2378 TCDF
Concentrations in Unbleached and Bleached Pulps (Five-
Mill Study) 2-19
2-4 Summary of TEQ and Corresponding 2378 TCDD and 2378 TCDF
Concentrations in Filtrates From Various Stages of the
Bleaching Process (Five-Mill Study) 2-21
2-5 Summary of TEQ and Corresponding 2378 TCDD and 2378 TCDF
Concentrations in Bleached Pulp Following Final Stage
of Bleaching Process (104-Mill Study) 2-24
2-6 Total Employees and Production Workers in the Entire
Paper and Allied Products Industry, 1985 2-25
2-7 Pulp Production and Number of Workers in Brown Stock
Washing Area Per Shift at Mills Surveyed in a NIOSH
Study _ 2-27
2-8 Staffing Arrangements, Workforce Size, Production Data,
and Job Task Assignments Per Shift for Bleaching Opera-
tions at Mills Surveyed in a NIOSH Study 2-29
2-9 Number of Workers in Papermaking Operations 2-31
(continued)
-------
TABLES (continued)
Number Page
2-10 Number of Commercial Users of Paper Products 2-35
2-11 Number of Workers in the Pulp and Paper Mill Job
Categories 2-36
3-1 Mass Balance Models 3-7
3-2A Estimated Inhalation Exposure to 2378 TCDD and 2378 TCDF
for Pulp Testers in Pulp Mills From Volatilization 3-13
3-2B Estimated Inhalation Exposure to 2378 TCDD and 2378 TCDF
for Bleach and Utility Operators in Pulp Mills From
Volatilization 3-14
3-3 Estimated Toxicity Equivalents and Percent Exposure Due to
2378 TCDD For Pulp Mill Workers From Volatilization 3-16
3-4 Assumptions and Uncertainties in Variables for Calculating
Life Average Daily TEQ from Daily Exposures 3-17
3-5 Assumptions and Uncertainties in Estimating Inhalation
Exposure to 2378 TCDD and 2378 TCDF for Pulp Mill
Workers From Volatilization 3-18
3-6 Estimated Dermal Exposure to 2378 TCDD and 2378 TCDF for
Pulp Mill Workers 3-24
3-7 Estimated Toxicity Equivalents and Percent Exposure Due to
2378 TCDD For Pulp Mill Workers From Dermal Exposure 3-25
3-8 Assumptions and Uncertainties in Estimating Dermal
Exposure to 2378 TCDD and 2378 TCDF for Pulp Mill
Workers 3-27
3-9 Estimated Inhalation Exposure to 2378 TCDD and 2378 TCDF
for Pulp Drying Workers From Volatilization 3-31
3-10 Estimated Toxicity Equivalents and Percent Exposure
Due to 2378 TCDD for Pulp Drying Workers From
Volatilization 3-32
3-11 Assumptions and Uncertainities in Estimating Inhalation
Exposure to 2378 TCDD and 2378 TCDF for Paper Mill
Workers From Volatilization 3-33
3-12 Estimated Dermal Exposure to 2378 TCDD and 2378 TCDF
for Pulp Drying Operators 3-36
(continued)
IV
-------
TABLES (continued)
Number Page
3-13 Estimated Dermal Exposure to 2378 TCDD and 2378 TCDF
for Pulp Drying Utility Operators 3-38
3-14 Estimated Toxicity Equivalents and Percent Exposure Due
to 2378 TCDD for Pulp-Drying Operations From Dermal
Exposure 3-39
3-15 Assumptions and Uncertainties in Estimating Dermal
Exposure to 2378 TCDD and 2378 TCDF for Pulp
Drying Operators 3-40
3-16 Particulate Size Distribution by Total Dust Concentration 3-43
3-17 Estimated Inhalation Exposure to 2378 TCDD and 2378 TCDF
for Paper Mill Workers From Volatilization 3-45
3-18 Estimated Toxicity Equivalents and Percent Exposure Due to
2378 TCDD for Paper Mill Operators From Volatilization 3-46
3-19 Assumptions and Uncertainties in Estimating Inhalation
Exposure to 2378 TCDD and 2378 TCDF for Paper Mill
Workers From Volatilization 3-47
3-20 Estimated Inhalation Exposure to 2378 TCDD and 2378 TCDF
for Paper Mill Operators From Particulate Matter 3-49
3-21 Estimated Toxicity Equivalents and Percent Exposure
Due to 2378 TCDD for Paper Mill Operators From
Particulate Matter 3-50
3-22 Assumption and Uncertainities in Estimating Inhalation
Exposure to 2378 TCDD and 2378 TCDF for Paper Mill
Workers From Particulate Matter 3-50
3-23 Estimated Dermal Exposure to 2378 TCDD and 2378 TCDF
For Wet-End Operators in Paper Mills 3-52
3-24 Estimated Dermal Exposure to 2378 TCDD and 2378 TCDF
for Paper Mill Dry-End Operators and Utility Operators 3-53
3-25 Estimated Toxicity Equivalents and Percent Exposure Due
to 2378 TCDD for Paper Mill Operators From Dermal
Exposure 3-55
3-26 Assumption and Uncertainities in Estimating Dermal
Exposure to 2378 TCDD and 2378 TCDF for Paper Mill
Workers 3-56
(continued)
-------
TABLES (continued)
Number Page
3-27 Personal Monitoring Results for Exposure to Dusts in
Paper Converting Operations 3-58
3-28 Estimated Inhalation Exposure to 2378 TCDD and 2378
TCDF for Paper Converting Workers From Particulate
Matter 3-59
3-29 Estimated Toxicity Equivalents and Percent Exposure Due
to 2378 TCDD for Paper Converting Operators From
Particulate Matter 3-61
3-30 Assumptions and Uncertainties in Estimating Inhalation
Exposure to 2378 TCDD and 2378 TCDF for Paper
Converting Workers From Particulate Matter 3-61
3-31 Estimated Dermal Exposure to 2378 TCDD and 2378 TCDF
For Paper Converting Workers 3-62
3-32 Estimated TCDD Equivalents and Percent Exposure Due to
2378 TCDD for Paper Converting Operators From Dermal
Exposure 3-63
3-33 Assumptions and Uncertainties in Estimating Dermal
Exposure to 2378 TCDD and 2378 TCDF for Paper
Converting Workers 3-64
3-34 Estimated Inhalation Exposure to 2378 TCDD and 2378
TCDF for Nonwoven Workers From Pulp Dust 3-66
3-35 Estimated Toxicity Equivalents and Percent Exposure Due to
2378 TCDD for Nonwoven Operators From Particulate Matter 3-67
3-36 Assumptions and Uncertainties in Estimating Inhalation
Exposure to 2378 TCDD and 2378 TCDF for Nonwoven
Workers From Particulate Matter 3-67
3-37 Estimated Dermal Exposure to 2378 TCDD and 2378 TCDF
for Nonwoven Workers 3-69
3-38 Estimated Toxicity Equivalents and Percent Exposure Due
to 2378 TCDD for Nonwoven Operators From Dermal Exposure 3-69
3-39 Assumptions and Uncertainities in Estimating Dermal
Exposure to 2378 TCDD and 2378 TCDF for Nonwoven
Workers 3-70
3-40 Estimated Dermal Exposure to 2378 TCDD and 2378 TCDF
for Commercial Users of Paper and Nonwoven Products 3-72
(continued)
VI
-------
TABLES (continued)
Number Page
3-41 Estimated Toxicity Equivalents and Percent Exposure
Due to 2378 TCDD for Commercial Users of Paper From
Dermal Exposure 3-74
3-42 Assumptions and Uncertainties in Estimating Dermal
Exposure to 2378 TCDD and 2378 TCDF for Commercial
Users of Paper Products 3-76
4-1 Summary of 2378 TCDD and 2378 TCDF Daily Inhalation
and Dermal Exposure Estimates for Workers Involved
in Manufacture, Processing, and Commercial Usage
of Pulp, Paper, and Paper Products 4-4
4-2 Summary of Daily Toxicity Equivalents Lifetime Average
Daily Toxicity Equivalents, and Percentage Exposure
to 2378 TCDD for Workers Involved in Manufacture,
Processing, and Commercial Usage of Pulp, Paper, and
Paper Products 4-6
4-3 Summary of Outer Bounds of Average Individual and
Population Risks Based on Toxicity Equivalents for
Workers Involved in Manufacturing, Processing, and
Commercial Usage of Pulp, Paper, and Paper Products 4-9
B-l Variables For Estimating Average Risks and Population
Risks B-3
-------
SECTION 1
INTRODUCTION
Various isomers of polychlorinated dibenzodioxins (PCDDs) and polychlo-
rinated dibenzofurans (PCDFs) have been found to be formed during bleaching
of wood pulp with chlorine or chlorine-based bleaching chemicals. Quanti-
tative studies conducted by the U.S. Environmental Protection Agency (EPA)
and the paper industry (which include the Five-Mill Study, the 104-Mill
Study, and the 25-Bleach Line Study) have shown that PCDDs and PCDFs may be
retained in low levels in bleached pulp, crude paper products (e.g., uncon-
verted paper, paperboard, fibers), and finished commercial and consumer grade
pulp-/paper-based products. Furthermore, PCDDs and PCDFs may also be re-
tained in wastewater and sludge generated during the manufacture of these
products or be released to the air through volatization or particulates.
On July 27, 1988, the EPA entered into a Consent Agreement with the
Environmental Defense Fund and National Wildlife Federation regarding a
schedule for review of PCDDs and PCDFs from pulp and paper mills. In re-
sponse to the Consent Decree, EPA is in the process of characterizing risks
in order to decide whether to initiate regulatory action to limit PCDD and
PCDF production at pulp and paper mills.
The purpose of this report is to aid OTS in its characterization of
worker exposure to PCDDs and PCDFs during the manufacturing, processing, and
commercial use of pulp, paper, and paper products. A separate report
1-1
-------
addresses worker exposure to PCDDs and PCDFs from the processing and commer-
cial use of sludge generated from wastewater treatment operations in paper
and pulp mills.
This report is organized into four sections. This section (Section 1)
provides the background and purpose of the study. Section 2 provides a
profile of industrial processes and operations that may result in exposure to
PCDDs and PCDFs during the manufacture of pulp, paper, and paper products.
It summarizes the results of the 5-Mill and 104-Mill studies, and includes a
workforce characterization for different operations involving the manufac-
ture, processing, and commercial usage of pulp, paper, and paper products.
Section 3 discusses the potential for dermal and inhalation exposure to PCDDs
and PCDFs for the processes/operations discussed in Section 2. It includes
engineering estimates of the levels of inhalation and dermal exposure for
workers involved in different types of processes. Section 4 presents the
conclusions and recommendations of this study, including a summary of 2,3,7,8-
tetrachlorodibenzo-p-dioxin (2378 TCDD) and 2,3,7,8-tetrachlorodibenzofuran
(2378 TCDF) daily exposure, toxicity equivalent (TEQ) daily exposure and
lifetime average daily exposures, and average and population risks for
workers involved in the manufacture, processing, and commercial use of pulp,
paper, and paper products. Appendix A presents 2378 TCDD and 2378 TCDF
concentrations for bleached pulp on a dry basis, as reported in the 104-mill
study. Appendix B presents the methodology employed in this report to calcu-
late average and population risks.
1-2
-------
SECTION 2
INDUSTRY PROFILE
This section presents descriptions of the operations in pulp, paper-
making, and nonwoven fabric production processes that result in formation of
and/or worker exposure to PCDDs and PCDFs. It includes results from quanti-
tative studies conducted by the EPA and the paper industry to determine
concentrations of PCDDs and PCDFs in streams from pulp and papermaking opera-
tions. In addition, the workforce is characterized in detail for those
processes with potential for exposure to PCDDs and PCDFs.
2.1 PULP, PAPER, AND NONWOVEN FABRIC MANUFACTURING OPERATIONS
The pulp, paper, and paperboard industry is a major industry in the
United States consisting of approximately 700 facilities producing 75 million
tons of product annually. It is divided into two major segments: integrated
mills where pulp, pulp and paper, or pulp and paperboard are produced; and
nonintegrated mills where paper and/or paperboard are manufactured from pulp
produced off site. Facilities range from large integrated kraft mills pro-
ducing over 2000 tons per day to small nonintegrated mills producing less
than 1.1 tons per day of product (Hanmer 1988).
The nonwoven industry manufactures many needle punched fabrics from
textile (including cellulose) fibers. The fibers are bonded to provide
integrity by means of heat bonding (fusion) or a surface application of
adhesive. Nonwoven fabric compositions are processed into numerous products
2-1
-------
including diapers, sanitary napkins, interliners, medical supplies, and both
consumer and work place (medical) garments. Usually nonwoven material which
are designed to absorb moisture utilize cellulosic fibers because of their
relatively high absorbency. There are approximately 125 plants which use
wood pulp to produce nonwovens (Cunningham 1990).
There are three basic pulping techniques currently used in industry:
mechanical, semi-chemical, and chemical. Mechanical pulping, which involves
separation of wood fibers by mechanical grinding, includes the stone ground-
wood refiner, the mechanical and thermomechanical pulping techniques. Semi-
chemical pulping, which involves chemical softening of wood chips prior to
mechanical grinding, includes the cold-caustic process and neutral sulfite
process. Chemical pulping, which involves the chemical separation of wood
fibers to dissolve lignin, includes dissolving pulp, sulfite pulp, and kraft
pulp techniques (OTA 1989).
The kraft pulping process dominates the pulp and paper industry, ac-
counting for greater than 75 percent of all pulp produced for paper and pa-
perboard in 1987. In addition, the greatest proportion of bleached chemical
pulp is produced by the kraft process, which accounts for 88 percent of pulp
bleached in 1987 (OTA 1989). There are four significant uses for bleached
pulp 1) the manufacture of paper and paperboard either in an integrated or
nonintegrated mill, 2) the manufacture of nonwoven textiles, 3) the manufac-
ture of cellulose or cellulose acetate, and 4) the manufacture of powdered
a-cellulose as a food additive. Cellulose is used for producing viscose
rayon textile fibers, cellulose di- and tri-acetate textile fibers, and
cellulose acetate cigarette filters. The kraft process requires the greatest
2-2
-------
degree of bleaching in order to achieve the desired color in the paper pro-
ducts. Mechanical pulping techniques are not studied in this report; mechan-
ical pulp bleaching processes uses bleaching agents other than chlorine such
as hydrogen peroxide or sodium hypochlorite (OTA 1989). This report focuses
on bleached kraft and sulfite pulp manufacture, the processing of pulp in
papermaking and nonwoven fabric production, and the commercial use of these
products. This report does not address other uses of pulp in the manufacture
of rayon or cellulose acetate for use in textile fibers, filters, and food
additives.
Regardless of the pulping technique employed at pulp and/or paper mills,
the same general steps are followed in the production of pulp. These include
raw material preparation (e.g., debarking and chipping); mechanical and/or
chemical separation of wood fibers (i.e., grinding, refining, or digestion)
to separate lignin; removal of coloring agents primarily in the form of
residual lignin oxidized to a soluble form by bleaching; and either on-site
paper formation or drying of pulp into sheets for shipment for off-site paper
formation or needle bonding into nonwoven products (OTA 1989). Figure 2-1
shows a flow diagram depicting operations in a typical integrated kraft pulp
and paper mill.
2.1.1 Raw Material Preparation
Wood can be received at the pulp mill in several forms. It may be
received as short logs of roundwood with bark still attached, as chips, or
even as waste sawdust. Typically, roundwood is used and it is debarked by
agitating in mechanical strippers or tumbling in steel drums in which wash
water may be applied. The debarked wood logs are chipped in a chipper and
subsequently are screened, sized, and temporarily stored (OTA 1989). As
2-3
-------
2-4
-------
dioxin/furan precursors have not yet been exposed to chlorinated compounds,
no worker exposure to PCDDs and PCDFs at this stage of the pulp and paper-
making process is expected unless PCDD/PCDF is introduced from raw materials
or recycled process water.
2.1.2 Fiber Separation
Fiber separation is accomplished in the kraft pulping process by cooking
the wood chips in the digester. Chips are fed countercurrently to a fresh
chemical stream known as white liquor which contains sodium hydroxide and
sodium sulfide. The chips are cooked with steam at 170° to 175°C for a
specific time period to separate fibers and to partially dissolve lignin and
other extractives (Soklow 1984).
After digestion is complete, the cooked pulp, which is referred to as
brown stock, exits the digester into a blow tank. The violent mechanical
action separates components of the wood, and steam and volatile materials are
separated out of the mixture. The cooked pulp is then sent to the brown
stock washing operation that separates cooked pulp from the spent cooking
liquor, which is referred to as black liquor. The black liquor is returned
to the chemical recovery operations (Soklow 1984).
The most common brown stock washing operation is a three-stage system
using rotary filters and countercurrent washing. The suspension of pulp and
black liquor is pumped into the first filter where it forms a cake and is
washed by effluent from the second filter. The first stage effluent is black
liquor which is sent to chemical recovery operations. The cake from the
first stage which has been resuspended in the effluent from the second filter
is pumped to the second filter. The cake formed in .the second filter is
washed by effluent from the third filter and is resuspended. It is pumped to
2-5
-------
the third filter in which the cake formed is washed with fresh hot water
(Soklow 1984).
2.1.3 Bleaching Operations
The brown stock must be bleached to produce light colored or white
papers preferred for many products, because it still contains an appreciable
amount of lignin and other discolorations. Bleaching not only removes and
decolorizes lignin but also serves to clean the brown stock of any dirt or
foreign matter. Bleaching also removes hemicellulose and extractives (OTA
1989).
Bleaching is normally accomplished in several stages, referred to as
multistage bleaching. A typical four-stage bleach plant is presented in
Figure 2-2. The bleaching chemicals and the order in which they are used
constitute the "bleaching sequence." Bleaching sequences generally contain
two phases within each sequence: a delignification segment, whose function
is to remove lignin; and a brightening segment, whose principal function is
to increase the brightness of the pulp. Delignification segments use chlo-
rination followed by extraction with sodium hydroxide. Brightening segments
use sodium hypochlorite and/or chlorine dioxide. Oxygen can be used for the
delignification and improved extraction of lignin during the alkali stage
(OTA 1989). Table 2-1 presents abbreviations used to designate bleaching
sequences.
Several of the most commonly used bleaching sequences in U.S. and Cana-
dian pulp mills are CEDED, CEDH, CEHDED, CEH, and CED. The specific opera-
tions of these sequences can be identified by referring to Table 2-1. An
2-6
-------
(RECYCLED OR RAW )
^ PROCESS WATER J-^
I BROWN I
UTOCK CHESTJ
r
^ I CHLOHIr
\\ V
1 CHLORINE 1
I TOWER J
j
x" 'XTOSkWhH
__^J WASHER V- ^>
L-
r
/^ N
D
I CAUSTIC I f "N
^ TOWER J (CAUSTIC SODA;
f PORTION TO
1 X" "N SEWER
^( WASHER \ *~
(^
1
[ HYPOCHLORITE | [ HYPOCHLORITE |
^ TOWER J ^PREPARATION^
f PORTION TO
/* N SEWER
^( WASHER ) *~
i^
r
[ CHLORINE J | CHLORINE )
^DIOXIDE TOWERj ^DIOXIDE PREPARATION J
f PORTION TO
X* N SEWER
^f WASHER V *-
1
I3LEACHED PULP 1
STOCK CHEST J
\ ON-SITE ]
I PAPERMAKING J
i
[ OFF-SITE PAPER | \
^MANUFACTURING^ U
1
NONWOVEN I
MANUFACTURING^
Figure 2-2. Typical four-stage bleach process.
(Soklow 1984 and OTA 1989)
2-7
-------
increasing number of mills, however, are currently using oxygen in combina-
tion with alkali for extraction (E ) and chlorine dioxide (CD, D ) in the
chlorination stage (OTA 1989).
TABLE 2-1. ABBREVIATIONS USED TO DESIGNATE BLEACHING SEQUENCES3
Symbol
C
E
H
D
P
0
N
Z
Description
Chlorination
Extraction with sodium hydroxide
Hypochlorite (sodium or calcium)
Chlorine dioxide
Hydrogen peroxide
Oxygen
Nitrogen dioxide
Ozone
a OTA 1989.
Note: Two bleaching agents may be used in a single stage. For
example, chlorine gas and chlorine dioxide are sometimes
combined in an early bleaching stage. If chlorine gas is
the predominant agent in the mixture, the treatment would
be designated "Cp." If the chlorine dioxide is the pre-
dominant agent in the mixture, the treatment would be
designated "D ."
In the bleaching process, each stage consists of a closed reaction tower
in which the pulp is retained in contact with the particular chemical agent
for the optimum retention time. The pulp is washed in vacuum washers or dif-
fusers and then proceeds to the next stage of the bleaching process. (Soklow
1984). The water used for washing is either raw water or white waters recy-
cled from papermaking operations. Typically, the wash water is introduced
into the washer associated with the final stage and proceeds by countercur-
rent flow to washers associated with the previous stage of bleaching. The
rinsing operations can be, and often are, open to the atmosphere. After the
final stage of bleaching, the bleached pulp is placed in a storage tank,
awaiting further processing into a variety of products (OTA 1989).
2-8
-------
All process operations used during a particular bleaching sequence
constitute the "bleach line." Bleach lines have an average pulp processing
rate of 600 tons/day. For the most part, pulp mills have either one or two
bleach lines (Hawks 1989).
2.1.4 Pulp Drying
Pulp to be used off site (in paper, nonwovens, textile fibers, filters,
food additives, etc.) is usually dried and either formed into sheets or baled
before shipment. Pulp drying is achieved by first partially dewatering the
pulp on a Fourdrinier or cylinder, pressing it into sheets, and then drying
it by contact with heated rotating cylinders or while conveying through a
hot-air drying chamber. Some mills in recent years have used flash-drying
systems in which the pulp is shredded after being dewatered and pressed, and
is then simultaneously conveyed and dried in a hot-air drying system. The
last preparation of the pulp before shipment is the final pressing and baling
of the pulp. Most drying operations in the industry are automated to some
degree. The white waters generated during pulp drying are usually recycled
back to the system in certain areas, such as the head box or the debarking
equipment (McCubbin 1989).
2.1.5 Papermaking Operations
Papermaking operations occur at integrated mills where both pulp and
paper are produced onsite, and at nonintegrated mills where paper is manufac-
tured from pulp produced offsite. Pulp is delivered from the pulp mill to
papermaking operations in an aqueous slurry (in the case of integrated facil-
ities), or as dry sheets, referred to as laps, which must be slushed prior to
processing (in the case of nonintegrated facilities) (Kirk-Othmer 1981a). In
2-9
-------
1987, 86 percent of the sulfite and kraft pulp consumption belonged to inte-
grated mills consuming their own pulp (Census 1988). Figure 2-3 presents a
flow diagram for a typical paper-making plant.
Almost all of the pulp is subjected to mechanical action prior to paper
sheet formation to improve the strength and other physical properties of the
finished sheet. This mechanical action is referred to as beating or refin-
ing. Various additives are introduced into the pulp depending upon the
desired grade of paper. These include sizing additives, fillers, and color-
ing agents. The refined pulp, into which the various additives are incorpo-
rated, is referred to as furnish (Soklow 1984).
The furnish is further diluted with recycled white water from the paper-
making machine to form a mixture containing approximately 0.5 percent fiber
(Soklow 1984). The diluted slurry is cleaned in cyclone cleaners and
screened in centrifugal screens prior to feeding into the "wet-end" of the
papermaking machine (OTA 1989).
The standard papermaking machine in the industry is the Fourdrinier
machine. There may be a wide range of papermaking machines used at a par-
ticular facility; in general, however, most plants operate two machines
(Kirk-Othmer 1981a). The number of machines used at a papermaking facility
typically ranges from one to four, with production volumes typically ranging
from 200 to 1500 tons per day (Hawks 1989). The diluted slurry passes
through the head box of this machine in which the slurry is uniformly
distributed over the desired sheet width. A sheet of pulp is formed on the
continuously-moving Fourdrinier wire which is a bronze or polymer screen.
Water drains from the pump sheet through the screen mesh; increased water
removal is facilitated by foils, table rolls, and suction boxes (Soklow
1984).
2-10
-------
f PROCESS I
IWATER J
i
I
FILTERED
WHITE WATER |
TANK
_f SAVEALL J
«FIBERS [ SAVEALL
f RICH WHITE |
UvATERTANiy
Figure 2-3. Typical closed papermaking process.
(Soklow1984)
2-11
-------
The wet sheet is continuously lifted from the Fourdrinier wire by the
couch roll and is transferred to the wet-pressing section. The wet-pressing
section is a woven felt belt where additional water is removed by pressure
rollers. The paper passes into the drying section where the remaining water
is removed by hot air circulated under a hooded ventilation system. After
drying, the sheet may pass through a coater (where a combination of pigments,
adhesives, and additives are applied) and an additional drying section, prior
to pressing through the calendar rolls. Pressing with calendar rolls imparts
a surface finish to the paper sheets by a combination of compression and fric-
tion. Usually two stacks of calendar rolls are used in paper manufacturing
operations. The paper sheets are then wound onto the reel (Soklow 1984).
Coating may occur in a separate operation following drying and calendering.
Finishing operations begin after the last operation of the papermaking
machine and end where the product leaves the mill. These operations include
coating, supercalendering, rewinding, slitting, cutting and sheeting, trim-
ming, packaging, and shipping. Supercalenders are used to impart a smoother
finish to the paper. Rewinders are used to reduce the machine width sheets
into smaller widths to meet customer specifications and are equipped with
slitters which are used to cut paper sheets into specific lengths. Trimmers
are used to trim the dimensions of a paper sheet to its final exact size.
The last part of the finishing operation involves packaging of the paper-
based product and preparing it for shipping (Soklow 1984).
A variety of finishing operations will be employed, depending upon the
grade of paper manufactured and the intended end-product use. In addition,
the product determines the mix of various types of pulp. For instance,
sulfite pulp is used in the manufacture of fine and printing papers; bleached
2-12
-------
kraft pulp is used to produce paperboard and tissue, printing, and writing
papers; and dissolving kraft or sulfite pulp is used in the manufacture of
viscose rayon and acetate fibers (OTA 1989).
2.1.6 Converting Operations
Nearly all paper is converted by undergoing further treatment after man-
ufacture. Among the many converting operations are embossing, impregnating,
saturating, laminating, and forming of specific shapes and sizes such as bags
and boxes (Kirk-Othmer 1981a). Converting operations may be done at paper-
making mills or at facilities which simply purchase paper stock from the
papermaking mills. There are thousands of converting establishments which
purchase and process paper stock into a wide variety of products. Conse-
quently, it is rather difficult to define a single converting operation which
would be representative of the entire converting industry (Festa 1989).
There are very limited data in the open literature on converting opera-
tions for bleached kraft paper. Bleached paper and paperboard are used for
products such as envelopes, tissue, writing, bond, and publication and print-
ing paper, shipping bags and sacks, linerboard, folding cartons, milk car-
tons, and paper plates and towels. The operations used to convert paper
stock into these products may involve cutting, slitting, and hole punching of
the paper stock. These operations may result in the creation of paper dust,
and involve manual handling of the paper stock and finished product.
2.1.7 Nonwovens
The nonwoven industry produces goods such as disposable diapers, hospi-
tal wear, bandages, medical supplies, sanitary napkins, wipes, towels, and
other associated products. Raw materials used for the production of these
goods include wood pulp, synthetic and textile fibers, and cellulosic fibers.
2-13
-------
Wood pulp makes up only 5 percent of the raw materials used in the nonwoven
industry (Nonwovens 1989). In 1988, the nonwoven industry consumed over
100,000 metric tons of bleached pulp that was manufactured (Grant 1990). The
most popular pulp converting production techniques include wet formation,
thermal bonding, fiber entanglement, and needle-punching. Dried pulp is
received in roll form from a pulp mill and is transported by forktruck to the
unwinder. The pulp roll is unwound into a pulp sheet and is manually or
automatically fed into the hammer mill, which shreds and fluffs the pulp
sheet. Typically, pulp dust resulting from the hammer mill is reclaimed
through a vacuum screen formed by a vacuum filter. The pulp fluff is then
placed on a forming belt and is machined, wrapped, and packaged using various
techniques and equipment. The nonwoven industry has an equally varied list
of products and manufacturing techniques as paper converting, therefore a
general description of the product finishing step could not be defined (Cun-
ningham 1990). Most machines used in the nonwoven industry are highly auto-
mated. Operations in the nonwoven industry include spun bonded, spun laced,
dry laid, wet laid, melt blown, and melt blown composites. All are not
adaptable to cellulosic fibers.
2.2 DIOXIN FORMATION IN PULP AND PAPER MILLS
Samples of pulp and paper mill wastewater treatment effluent and sludge,
as well as bleached pulp and bleached pulp-based products, have shown that
PCDDs and PCDFs are formed during the bleaching of pulp if chlorine or pos-
sibly chlorine compounds are used as bleaching agents. Three isomers domi-
nate the PCDD and PCDF formation during chlorine bleaching of chemical pulp
(Voss 1988):
2-14
-------
2,3,7,8-tetrachlorodibenzo-p-dioxin (2378 TCDD)
2,3,7,8-tetrachlorodibenzofuran (2378 TCDF)
1,2,7,8-tetrachlorodibenzofuran (1278 TCDF)
Of the TCDD isomers, only 2378 TCDD was found in detectable quantities in
pulp mill wastes. The total of other TCDDs were not detected at a detection
level of 1 ppt (Kuehl et al. 1987). The TCDF compounds found in pulp mill
wastes were dominated by two isomers, 2378 TCDF and 1278 TCDF, but other TCDF
isomers were present in minimal quantities. Previous studies have mainly fo-
cused on 2378 TCDD, which is the most toxic member of the PCDD and PCDF fami-
ly, and 2378 TCDF, which is believed to be one-tenth as toxic as 2378 TCDD.
2.2.1 PCDD and PCDF Precursors and Formation
The chemical reactions and conditions under which PCDDs and PCDFs are
formed in pulp and papermaking operations are not yet completely understood.
PCDDs and PCDFs are formed as byproducts during these manufacturing opera-
tions and are considered contaminants. Chiorination of a PCDD or PCDF pre-
cursors in the pulp during bleaching stages may result in the production of
chlorinated dioxins, furans, and other chlorinated organic compounds which
are of concern to human health.
Possible sources of PCDD and PCDF precursors include natural constitu-
ents in wood, contaminants in plant pipes and machinery, and additives (OTA
1989). PCDD/PCDF formation may result from condensation of chlorophenols
formed by chlorination of naturally occurring phenolic compounds such as
lignin, which comprises 25 percent of wood (Beck 1988). To date, the only
substances found to contain precursors that have been studied in depth are
the oil-based defoamers, which are additives that enhance the washing of
unbleached pulp by controlling foam production.
2-15
-------
A recent Canadian study (Voss 1988) has uncovered the possibility that
oil-based defoamer additives may be serving as carriers of unchlorinated pre-
cursor compounds. The study positively identified the presence of one PCDF
precursor, dibenzofuran (DBF), which is a contaminant in oil-based defoamers.
The study revealed the potential for DBF contamination in tap water used for
process makeup water, air, and raw wood. The presence of another precursor,
dibenzo-p-dioxin (DBF), was suspected in oil-based defoamers; however, it
could not be confirmed because of excessive interference from other substanc-
es during analysis. Tests revealed that the addition of oil-based defoamers
resulted in elevated levels of 2378 TCDD and 2378 TCDF in the final chlori-
nated pulp. The pulp and paper industry is currently investigating replace-
ments for oil-based defoamers, but little information is available on the
extent of replacement of oil-based defoamers or the limitations of the sub-
stitutes. One contact stated that his company successfully replaced the
oil-based defoamers without affecting operations. A NCASI/API joint study is
currently being performed as a followup study to the 104-Mill Study. This
study will investigate the effectiveness of measures taken by certain mills
to reduce PCDDs and PCDFs. The followup study will include the extent of
oil-based defoamer replacement and the resulting reduction of PCDD/PCDF
production (Grant, 1990). Table 2-2 presents data on the effect of defoamer
addition to laboratory-prepared brown stock kraft pulp on subsequent 2378
TCDD and 2378 TCDF formation during the bleaching process. The data were
collected from studies using laboratory-prepared western hemlock kraft pulp.
Various oil-based defoamers were added at 1 percent the weight of the pulp,
which is 10 times greater than normal industry practice. This was done so
2-16
-------
that oil-based defoamers could be identified as being the source of the
precursors.
TABLE 2-2. EFFECT OF DEFOAMER ADDITION TO BROWNSTOCK KRAFT PULP
ON SUBSEQUENT DIOXIN FORMATION DURING THE BLEACHING PROCESS3
2378 TCDD
Pulp concentration,
additive ppt
None
1% of oil -based defoamer A
(virgin oil base)
1% of oil -based defoamer B
from Canadian kraft mill
1% of oil -based defoamer C
(recycled oil base)
1% of recycled oil base used in
defoamer C
11
110
81
140
170
2378 TCDF
concentration,
ppt
160
910
280
1200
1400
a Source: (Voss 1988)
2.2.2 Quantitative Studies
In an attempt to quantify concentrations of PCDD and PCDF produced
during pulp and paper manufacturing operations, several recent studies have
been undertaken by the EPA and the paper industry. These studies include the
Cooperative Dioxin Screening Study (or Five-Mill Study), the 104-Mill Study,
and the 25 Bleach Line Study. The Five-Mill Study and 104-Mill Study were
undertaken as a joint investigation by EPA and the industry, whereas the
25 Bleach Line Study is solely industry-sponsored. Data have been released
from the Cooperative Dioxin Screening Study and the 104-Mill Study; however,
the results of the 25 Bleach Line Study (which involves measurements of PCDD
and PCDF concentrations in effluent, sludge, pulp and intermediate pulps, and
filtrates) will not be available until early 1990 (Bond 1989).
2-17
-------
All of these studies involve analysis of PCDD and PCDF concentrations
from the bleaching of kraft pulp. Kraft pulp was selected for a number of
reasons. Sampling data from screening studies conducted by EPA revealed that
the highest concentrations of PCDDs and PCDFs within the paper industry were
associated with kraft pulp mills (Hanmer 1988). Chlorine and chlorine deriv-
atives, which are necessary for PCDD and PCDF formation, are used in the
kraft pulp bleaching process.
2.2.2.1 Cooperative Dioxin Screening Study--
The Cooperative Dioxin Screening Study, or Five-Mill Study, was conduct-
ed from June 1986 to January 1987 at five bleached kraft pulp and paper mills
as a joint investigation by EPA and the industry. The study focused on three
mills known to have PCDD/PCDF in their waste sludge and two additional mills
that were volunteered by their firms to provide geographical coverage. In
this study, concentrations of 2378 TCDD and 2378 TCDF were measured in un-
bleached and bleached pulps, bleach line filtrates, paper machine wastewater,
sludge, and wastewater effluent. The results of this study indicated that
the bleaching of kraft pulp with chlorine and chlorine derivatives is respon-
sible for the production of 2378 TCDD and 2378 TCDF as byproducts of the
kraft pulping process.
Table 2-3 presents a summary of the range, mean, and median concentra-
tions for 2378 TCDD toxicity equivalents (TEQ) and the corresponding range of
2378 TCDD and 2378 TCDF concentrations in unbleached and bleached pulp from
the five mills. The TEQ values reflect the relative toxicity of 2378 TCDF
with respect to 2378 TCDD. Equation 1A is used to calculate TEQ while Equa-
tion IB is used for calculating the percent contribution due to 2378 TCDD.
2-18
-------
TEQ = C
TCDD
TCDF
Equation 1A
%TCDD =
where
x 100
Equation IB
TCDD TCDF
TEQ = toxicity equivalent, ppt
CTCDD = concentration of 2378 TCDD in pulp, ppt
CTCDF = concentration of 2378 TCDF in pulp, ppt
%TCDD = percent of the contribution due to 2378 TCDD, percent
The low and high plant TEQs provide the lower and upper ranges of 2378 TCDD
and 2378 TCDF concentrations.
TABLE 2-3. SUMMARY OF TEQ AND CORRESPONDING 2378 TCDD AND
2378 TCDF CONCENTRATIONS IN UNBLEACHED AND BLEACHED PULPS (FIVE-MILL STUDY)a
(ppt)
Pulp type
Unbleached0
Bleachedd
a EPA 1988.
w * 1 ** *-. £ M
No. of
samples
8
9
TEQ
b
Range
0.17(57)-0. 72(18)
0.56(45) - 69(22)
Concentrations reported on
Mean Median
0.40 0.36
22.2 9.6
a dry basis.
2378
TCDD range
0.16-0.49
0.5-51
~ OOTO Trnn
2378
TCDF range
0.12-2.3
0.6-180
c 2378 TCDD was not detected in all samples with detection levels of 0.3 to
1 ppt. 2378 TCDF was not detected in five samples with detection levels of
0.16 to 0.27 ppt.
2378 TCDD was not detected in two samples with detection levels of 0.62
and 1.0 ppt. 2378 TCDF was not detected in one sample with a detection level
of 1.2 ppt.
For the purpose of calculating TEQ range, mean, and median concentra-
tions, PEI assumed the concentration of samples in which 2378 TCDD and 2378
TCDF were not detected to be half of the detection level. It must be noted
2-19
-------
that the mean and median concentrations presented in Table 2-3 may not neces-
sarily be representative of all pulp and paper mills.
Although no 2378 TCDD was detected in unbleached pulp, three of the sev-
en samples tested above detection levels for 2378 TCDF. The positive analy-
sis for 2378 TCDF in unbleached pulp may be due to reuse of PCDF and PCDD
contaminated paper machine wastewater for brown stock pulping or dilution at
the mill where the samples were taken. Most of the bleached pulp samples
tested positively for 2378 TCDD and 2378 TCDF, which led to the hypothesis
that their formation originated in the kraft bleaching process.
Table 2-4 presents a summary of the range, mean, and median concentra-
tions for the TEQ and corresponding range of 2378 TCDD and 2378 TCDF concen-
trations in untreated filtrates from the various stages of the bleaching
processes used at the five mills. All of the samples tested above detection
levels for 2378 TCDF. In five samples, 2378 TCDD was not detected. For the
purpose of calculating TEQ range, mean, and median concentrations, PEI as-
sumed the concentration of samples in which 2378 TCDD and 2378 TCDF were not
detected to be half of the detection level. It must be noted that the mean
and median concentrations presented in Table 2-4 may not necessarily be
representative of all pulp and paper mills. The low and high plant TEQs
provide the data points for the lower and upper ranges of 2378 TCDD and 2378
TCDF concentrations.
Table 2-4 shows that filtrate wastewater from the caustic extraction
stage generally contained the highest concentrations of 2378 TCDD and 2378
TCDF, followed by the hypochlorite, chlorination, and chlorine dioxide stag-
es. The bleach plant filtrate data do not clearly define the point of 2378
TCDD and 2378 TCDF formation but do indicate formation in the chlorination
2-20
-------
TABLE 2-4. SUMMARY OF TEQ AND CORRESPONDING 2378 TCDD AND 2378 TCDF
CONCENTRATIONS IN FILTRATES FROM VARIOUS
STAGES OF THE BLEACHING PROCESS (FIVE-MILL STUDY)3
(ppt)
TEQ
No. of .
Filtrate sam- Range
type
C stages
(C, CD, C/D)C
E stages .
(E, EQ)d
H stages
(H, H/D)e
D stages (D)
pies
8
9
10
2
(3)
0.012(3)-0.62(6)
0.012(10)-5.1
0.019(7)-2.8(17)
0.0034(13)-0. 043(19)
Mean Median
0
1
0
0
.14
.61
.62
.023
0.059
0.31
0.28
NA9
2378
TCDD range
0.
0.
0.
0.
003-0
006-1
008-1
002-0
.24
.8
.9
.03
2378
TCDF range
0
0
0
0
.093-3.
.056-33
.11-9.2
.014-0.
8
13
3 EPA 1988.
Values in parentheses are percent contributions due to 2378 TCDD.
c C Stage represents chlorination stage of the mills. C represents use of
chlorine only. Cn represents use of a mixture of chlorine dioxide and
chlorine, which is predominantly chlorine. C/D represents use of a mixture
of chlorine and chlorine dioxide. 2378 TCDD was not detected in one sample
(Cn) with a detection level of 0.006 ppt.
H
E Stage represents caustic extraction stage following the bleaching stages
at the mills. E represents use of sodium hydroxide only. EQ represents
use of a mixture of sodium hydroxide and oxygen, which is predominantly
sodium hydroxide. 2378 TCDD was not detected in two samples (both En) with
detection levels of 0.011 and 0.033 ppt.
e H Stage represents hypochlorite stage of the mills. H represents use of
sodium or calcium hypochlorite only. H/D represents use of a mixture of
sodium or calcium hypochlorite and chlorine dioxide. 2378 TCDD was not
detected in one sample (H) with a detection limit of 0.017 ppt.
D stage represents chlorine dioxide stage at the mills. D represents use
of chlorine dioxide only. 2378 TCDD was not detected in one sample with a
detection level of 0.003 ppt.
9 NA = Not applicable.
2-21
-------
(C) stage and possibly in the extraction (E) stage. It is not possible from
the data to determine whether 2378 TCDD and 2378 TCDF are formed in the C
stage and extracted in the E stage or if there is additional formation in the
E stage. The data also suggest formation of these compounds in subsequent
bleaching stages (EPA 1988).
In summary, the results of the Cooperative Dioxin Screening Study indi-
cate that 2378 TCDD and 2378 TCDF are formed during the bleaching of kraft
hardwood and softwood pulps with chlorine and chlorine derivatives, and that
they are the principal PCDDs and PCDFs found in samples.
At the time of the Five-Mill Study, information regarding the possibil-
ity of the presence of PCDD and PCDF precursors in oil-based defoamers was
not available. Depending on the extent of use of water-based or other types
of defoamers in industry today (and a knowledge of the washing stages in
which they are introduced), concentrations of 2378 TCDD and 2378 TCDF found
in the Five-Mill Study may therefore be higher than those representative of
current industry practices.
2.2.2.2 The 104-Mill Study
The 104-Mill Study or Cooperative Dioxin Study was conducted from April
1988 to August 1989 at 104 domestic pulp mills manufacturing chemical pulp as
a joint investigation by EPA and the industry. In this study, concentrations
of 2378 TCDD and 2378 TCDF were measured at 87 kraft (sulfate) and 17 sulfite
pulp mills that use chlorine-based bleaching processes (chlorine, chlorine
dioxide, or hypochlorite). Samples were taken of the following: 1) bleached
pulp after the final stage of bleaching, 2) combined dewatered wastewater
sludge, and 3) treated wastewater effluent prior to dilution with cooling
water (UPIU 1989). The study also collected data on waste treatment opera-
tions, waste discharge characteristics, and sludge disposal information.
2-22
-------
Appendix A to this report presents 2378 TCDD and 2378 TCDF concentrations on
a dry basis in bleached pulp samples for the 104 plants.
The 2378 TCDD concentrations in sulfite pulp were much lower than the
kraft pulp concentrations, ranging from 1 ppt to 15 ppt with no detection
corresponding to a detection level of 1 ppt (UPIU 1989). This finding con-
firms the EPA screening studies which showed that the highest level of PCDD/
PCDF concentrations were associated with the kraft process. Kraft pulp
typically will require more bleaching stages than will sulfite pulp to bring
it to the same level of brightness (Kirk-Othmer 1981b).
PEI evaluated the reported concentrations of 2378 TCDD and 2378 TCDF in
bleached pulp samples. An analysis of the concentrations in the sludge will
be presented in a separate report. For the purpose of calculating mean and
median TEQ concentrations, PEI assumed the concentrations of samples in which
2378 TCDD and 2378 TCDF were not detected to be half of the detection level,
and samples which were not quantified were rejected. The results of this
analysis are presented in Table 2-5. The low and high plant TEQs provide the
data points for the lower and upper ranges of 2378 TCDD and 2378 TCDF concen-
trations, used for the exposure and risk assessment estimates in this report.
It must be noted that the concentrations of 2378 TCDD and 2378 TCDF mea-
sured in pulp and papermaking operations do not necessarily represent worker
exposure to these compounds. The data collected from the 104-Mill Study are
used in Section 3 for estimating occupational exposures. Worker exposure
depends on a variety of conditions (e.g., engineering controls, personal
protective equipment, work practices) which are addressed in Section 3.
2-23
-------
TABLE 2-5. SUMMARY OF TEQ AND CORRESPONDING 2378 TCDD AND
2378 TCDF CONCENTRATIONS IN BLEACHED PULP
FOLLOWING FINAL STAGE OF BLEACHING (104-MILL STUDY)3
(ppt)
TEQ
2378 2378
No. of samples Range Mean Median TCDD range TCDF range
219C 0.13(29)-311(2) 17.0 6.9 0.10-49 0.25-2620
3 Information furnished by U.S. Environmental Protection Agency, Washington,
D.C., based on 104-mill survey; updated results provided in computer
diskette form. Concentrations reported on a dry basis.
Values in parentheses are percent contributors due to 2378 TCDD.
c 2378 TCDD was not detected in 39 samples. 2378 TCDF was not detected in
10 samples.
2.2.2.3 Analyses of Paper Products
The National Council of the Paper Industry for Air and Stream Improve-
ment (NCASI) has performed some preliminary analyses for 2378 TCDD and 2378
TCDF in composites of several bleached pulp-based products. Because of the
limited number of samples analyzed in the NCASI effort, 2378 TCDD and 2378
TCDF concentrations in the pulp from the comprehensive 104-Mill Study were
used for all exposure estimation calculations found in Section 3.
2.3 PULP AND PAPER INDUSTRY WORKFORCE CHARACTERIZATION
In 1986, the paper and allied products industry employed over 674,000
people, of which approximately three-fourths were directly involved in pulp
and paper production (OTA 1989). Table 2-6 summarizes the total number of
employees and production workers in 1985 in the various paper and allied
product categories. Both integrated and nonintegrated paper mills are in-
cluded in Table 2-6. Some data on the number of workers in the pulp and
paper industry were also obtained from the National Occupational Exposure
Survey (NOES); however, the NOES data only included a limited number of
2-24
-------
plants, making the data incomplete. As Table 2-6 shows, over 75 percent of
the employees in the industry are production workers. Not all of these pro-
duction workers, however, are exposed to PCDDs and PCDFs; the exposure varies
for different job categories. Worker job descriptions and characteristics
are discussed herein for the areas/process operations where exposure can oc-
cur: brown stock washing, bleaching, papermaking and finishing, pulp-drying,
and paper and pulp converting. It is important to note that job categories
and descriptions vary considerably throughout the industry depending on
equipment layout, degree of automation, and complexity.
TABLE 2-6. TOTAL EMPLOYEES AND PRODUCTION WORKERS IN THE ENTIRE
PAPER AND ALLIED PRODUCTS INDUSTRY, 1985a
Industry group
Pulp mills
Paper mills, except building paper
Paperboard mills
Miscellaneous converted paper 'products
Paperboard containers and boxes
Building paper and board mills
Total
Total number
of employees
16,000
132,000
54,000
211,000
188,000
4,000
604,000
Production
workers
12,000
102,000
41,000
161,000
143,000
3,000
462,000
a (Census 1987)
Generally, pulp and papermaking mills operate 24 hours per day, 4 shifts
per 24-hour day (one shift is off), 7 days per week. Paper converting opera-
tions usually shut down at night and on weekends (Soklow 1984).
The workforce characterization in kraft pulp and paper mills has not
been fully studied. A limited amount of information was obtained from such
sources as EPA literature, NIOSH databases, industry data, and various
2-25
-------
industrial contacts. However, numerous additional assumptions were needed to
calculate the number of workers in each job category. It was assumed that
the number of workers in kraft pulp mills was proportional to the ratio of
the amount of bleached pulp to the total amount of pulp produced. Other
assumptions are stated in the respective sections.
2.3.1 Brown Stock Washing
In brown stock washing operations, the potential for PCDD/PCDF exposure
exists only if paper machine white waters, which have been used in the
processing of bleached pulp, are recycled. However, the recycling of white
waters is a rare practice in brown stock washing operations throughout the
pulp and paper industry. The job categories in brown stock washing opera-
tions which could have the greatest potential for exposure to PCDDs and PCDFs
are the wash and screen room operators, pulp tests, and utility employees.
Table 2-7 summarizes the number of these employees per shift and pulp produc-
tion at mills surveyed in a study conducted by the National Institute for
Occupational Safety and Health (NIOSH 1983).
The wash and screen room operators monitor and control operations of
washer lines, screens, filtrates, and high-density storage tanks (Soklow
1984). The number of wash and screen operators in a plant may range from 0
to 4, averaging 1 to 2 per shift (NIOSH 1983).
Pulp testers are responsible for retrieving and analyzing production
area samples. Samples are usually analyzed in laboratory areas located away
from the production area such as a wash/screen control room (Soklow, 84).
The number of testers per shift may range from 0 to 3, but is usually 1
(NIOSH 1983).
2-26
-------
TABLE 2-7. PULP PRODUCTION AND NUMBER OF WORKERS IN BROWN,STOCK
WASHING AREA PER SHIFT AT MILLS SURVEYED IN A NIOSH STUDY3
Mill
No.
1
8
11
20
26
29
33
36
38
Pulp production
(tons/day)
800
250
NAb
1,050
1,200
1,300
100
NAb
950
Wash
and screen
operator
lc
1
4d
2
2
-
-
1
1
Pulp tester
1
1
2e
1
1
3f
-
1
1
Utility
empl oyee
1
1
-
-
-
-
-
-
1
3 (NIOSH 1983)
b NA = Not available.
Also responsible for bleach plant.
Wash room operator, two helpers, and a screen room operator.
e Pulp tester (brown stock washers, refiners) and stock sampler (digester),
Collect and analyze samples from pulp mill and bleach plant.
2-27
-------
Utility employees are responsible for keeping the pulp mill clean, con-
ducting routine maintenance, and assisting the operators (EPA 1988). The
number of utility employees per shift may range from 0 to 1 (NIOSH 1983).
2.3.2 Bleaching Operations
In the bleaching operations, PCDDs and PCDFs are formed through the use
of chlorine or chlorine derivatives, and thus are expected to be at their
highest concentrations in the pulp and papermaking process. Four major work-
er activities include: 1) process monitoring and control; 2) manual opera-
tion, and adjustment of equipment, or inspection; 3) process quality control
sampling and testing; and 4) housekeeping and spill cleanup (NIOSH 1983).
Table 2-8 presents staffing arrangements, workforce size, production
data, and job task assignments for bleaching operations at mills surveyed
during a NIOSH study (NIOSH 1983). Table 2-8 confirms the wide variety of
job descriptions/categories found throughout the paper industry. Many of the
job responsibilities are performed by workers in different job categories,
but no two bleach plant workers perform the exact same duties. This overlap
is found throughout the pulp and paper industry. The operator is solely
responsible for process monitoring and control but is assisted by equipment
tenders and helpers for equipment inspection and operation. Quality control
testing is performed primarily by helpers, although assistant operators may
be assigned to this task. Housekeeping and spill cleanup operations are
usually done by utility employees, although operators and assistant operators
may perform these functions in small mills. The total number of production
workers per shift ranges from 2 to 5 (NIOSH 1983). The bleach plant popula-
tion potentially exposed to dioxins and dibenzofurans is estimated to be
2-28
-------
to
^ >-
CO Q
1 1
CO
CO
o m
-3 co
o
Q 1-1
rf? ^~
-
O UJ
i o:
O ^
^
^3 CO
o
O CO
0 1
1 1
1 1 1
I* ^
co
co
1 1 1 2^
O O
Q£ I i
O I--
LL. <
SX fV
or ui
0 0.
3 O
«% £_3
co z
1 >
z n:
1 1 i tj
S et
UJ UJ
o _i
or a:
ry o
«I U.
CD 1
Z U.
HH 1 1
li -T-
I_I_ i/~t
^£
H CC
CO UJ
Q.
{/}
CO 1
1 Z
CM UJ
UJ Z
i cj
00 -.
«C CO
1 CO
CX
Ol 3
C C
i- IO
Q. Ol
0)-0i-
01 C U
O> *° t
3 ^
o a.
X OO
tn
c
ft >> Ol
e ffo c
Ol f- kt-
»- I 4-» 4-»
in 10 c in
UI 3 O 0)
« cro 1
in
8 i
"I C -^
4J O 4J
k e i- 10
O Ol 4-1 U
«> e o oi
IO CX Ol Q.
Z f- CXO
3 in
O- C TJ
LUI-H e
oi p
c u
in t- 4->
in u c
Ol O O
k°c-a
o. o c
X. 10
^^
oi in
i- Ol
JZ U
u c
10 oi
Ol 3
cr
CO 01
o u m
IO 01
Ol C
O r- -i-
Z J3 r
C *~^
o >,
*- IO
CL U .
r 3 «
3 TU C
a. o o
i- 4->
CX '
d 1"i->
Z i c in 14-
P P k -r-
t-j 1. ^- 01 J=
4-> U "tl "*
O 14- 3 O k
(- P T3 S 01
CX
c
g
of
Ol
c
z
i.
10
Ol
c
£
ia
4->
o
f- Z
X
^J
f
^J
3
^_
^
E t-
01
CXJrf
cis
1.
a.
r- 4J
3 IA
O. --«
o «-
c a>
CM -o
1*2
o y
4-1 B
10 S.
ft) 3
CL ^f
o ai
t-
o
£
o
a
LU
o
UJ
*-l
o
o
ao
in
i
01 o>
c c
JZ r
o -o
10 C
01 10
JQ"
r~
0 S
t- §
<4- JZ
IO U
4J
VI JZ
u
o 10
Ol Ol
C r-
o c
U 10
r-4
O
u
Ol
c u
iO O
"a.
J!» j^J
U »-
CO 3
u 4-1 ai
IO C CX
Ol 10 r
p- r- 01
CO CXJ=
u
s
T3 k.
c ai
IO CX
4J
L. C
<^ ^
O CX
V.
o
4J
£
s.
0
o
UI
t-4
in
CM
C^ Ol
4=.J:
u -a
01 10
^
p_
0 S
<4- 1
t- J=
IO U
in j=
u
T9 iO
.JE 3
o c
O IO
o
u
o
«
L,
Ol
CX
S. P
p
u c
P IO
4J *J
10 in
U -r-
Oi in
CX in
O 10
C k.
5°
in ia
in at
in ex
«t p
in
in
in
i- p
P 4J
IO
k. L.
P Ol
4-> CL
2°
&. C
O 3 X
C CX
ia >>
in p -p-
in L. f-
in p 4-1
«« 4-> 3
O 4-> O)
IO C 4->
oi ia in
i r- Ol
ca cX4->
L,
p
4J
iO
1.
Ol
a.
p
4->
C
10
I/I
r-
in
in
L.
P
ie
k
Ol
CX
o
a
a
UJ
a
LU
0
CM
O
o
CM
« 1
Ol Ol
c c
u -a
10 C
ai ie
J3
r
V. IO
P O
4- 1
a 10
O U
C i
l~ ^
1?
tJ 10
in
CM
CX
g.
X
k 4J
P -
W *^
P 4-1
4J 3 k
IO Ol
Ol i k
<§"iS
5
*O)
JZ
u
IO
ai
o k
IO CX
P JZ
10 4J
k. C
CLf~~
O CX
k.
p
£
s.
0
a
UJ
r ^
T-l
O
CVJ
IO
CM
^i^
r~
+J
U
r
^3
in
ai
01
r
in
in
IO
14- C
<4- 10
ia
+J CX
in
ai u
4-> 10
a oi
Ol p
GO 4J
O
CO
i
IO
k
CL
p
c
IO
in
in k
in p
k
in
ai
p
(O
k
Ol
CX
p
c
2
in
in
in
<.
k
p
IO
k
S.
o
o
UJ
u
f 1
o
o
ro
^.
r
U
'k
in
Ol
Ol
in
m
IO
14- ia
4-1 a.
m
JZ
Oi u
4J 10
24!
10 J3
a.
Ol P
00 4->
in
14-
Ol
f
£
k
^^ P
4^ 44
»- IO
1- Ol
4-> Q.
3 P
k
5
2
£
0
k
p
IO
ai
o.
0
in
k
p
iO Ol
Ol Ol IO
CX k. Ol
O O r
O
UJ
a
UJ
u
CM
1
!b
P IO
k -t-J
a. ai
in
y
ID
Ol r
J3 U
ll
U
t/)
a> ^
^o o
^ "O
S.k
O 4J
14- k in
14- p .^
10 X m
4-> IO
in ai 4J
Oi P Ol
2 in^
3.21
Ol -r- 10
OO ^- JZ
fl^
CO
in
in
11
U
p
CX
01
c
a.
3
CX
01
£
"3
in
Ol
JZ
4->
in
Ol
10
3
f
U
2
CM
CXJ
,
0
21
f_p
>
p ai
in r
k >2?
S. 1o
3 >
in ie
in 4->
Oi p
-o z
3
p- II
U
X <£
LU Z
u -o
2-29
-------
1,300 workers total, based on the assumption that there are three employees
on each of the four shifts within the 104 mills.
2.3.3 Papermaking and Finishing
In this stage, additives such as coatings, colorings, or sizing agents
can be mixed with the pulp stock. Job categories potentially exposed to
PCDDs and PCDFs include operators, assistants, and utility employees. Ta-
ble 2-9 presents the estimated number of workers per shift for general
papermaking operations. The number of workers per shift in the papermaking
operations will vary depending on 1) number and location of paper machines,
coaters, and slitters/rewinders; 2) the type and complexity of wet-end opera-
tions; 3) the complexity, speed, and extent of automation of papermaking
equipment; and 4) the type, number, and complexity of the dry-end operations
(NIOSH 1983).
Wet-end additives/stock preparation operators are responsible for oper-
ating and monitoring the equipment during the following types of activities:
dry pulp dissolving; beating, refining, thickening, cleaning, and blending of
pulps; preparing additives such as sizes, fillers, and covering agents; and
mixing and blending of ingredients. Operators in the coating preparation
category are responsible for the preparation of the coatings, unloading the
raw materials, and monitoring the system. Coating ingredients include de-
foamers, sodium hydroxide, ammonia, and latex. The paper machine wet-end
operators perform web forming and water removal by suction and/or pressing in
a Fourdrinier or cylinder machine which removes most of the water from the
formed sheet (Soklow 1984).
2-30
-------
TABLE 2-9. NUMBER OF WORKERS IN PAPERMAKING OPERATIONS0
General process
operations
Wet-end additives and
stock preparations
Coating preparation
Paper machine
wet-end
Paper machine
dry-end
Off -machine coating
Estimated No.
of workers
General job per shift
categories (per machine)
Operator (beater man)
Assistant
Utility
Operator
Assistant
Utility
Machine tender
Assistant
Utility
Back tender
Splitter/winder operator
(3rd hand)
Assistants (4th/5th hands)
Coater operator
Utility
Operator
Assistant
Utility
1
1-2
0-1
1
1-2
0-1
1
0-1
0-1
1
1
1-3
1
0-2
1
1
0-2
(NIOSH 1983)
2-31
-------
Dry-end paper machine operators are responsible for web drying, on-
machine coating and drying, reeling, on-machine calendering, slitting/rewind-
ing, quality control testing, and packaging and shipping. Drying operations
utilize hot air circulated under a hooded ventilation system for the final
drying step. The back tender is responsible for the drying, reeling, and
calendering operations. The third-hand's duties include operating the winder
and finishing the rolls for wrapping. The third-hand spends the majority of
his time at the winder control console; however, the third-hand also performs
the area blowdown operations (cleaning of equipment to remove excess paper
dust). Fourth- and fifth-hands do various tasks including threading paper,
preparing cores, and assisting with the blowdown (Soklow 1984).
Off-machine coating operations include application of the coating formu-
lation, paper drying, and rewinding of the paper into rolls. Operators are
responsible for monitoring the process, checking paper quality, assisting the
utility personnel with loading or unloading rolls of coated paper, and clean-
ing of the dryer during upsets (Soklow 1984).
The paper mill population potentially exposed to PCDDs and PCDFs is
estimated to be 32,000 workers total, based on the assumption that there are
two machines per facility, with 18 people per each of the four shifts working
at each machine in the 221 facilities processing bleached kraft and sulfite
pulp. The number of facilities processing bleached pulp was estimated to be
proportional to the quantity of bleached pulp production.
2.3.4 Pulp Drying
In the drying operations there are typically three to five workers per
shift, including one to three equipment operators, a fork-truck driver, and a
utility person. No information was available on the total number of pulp
2-32
-------
drying workers. The number of pulp drying operators potentially exposed to
PCDDs and PCDFs was estimated to be 240 people assuming four workers in each
shift of the 15 mills that use pulp drying (Census 1988). Operators in the
drying stage of pulp production are responsible for monitoring the equipment,
weighing the pulp sheets, off-loading and stacking the pressed pulp sheets,
and cutting and baling the dry pulp. Fork-truck drivers are responsible for
removing the finished bales of pulp and stacking them for shipment. The
utility operators clean up any spills and assist the operators in keeping the
production area clean (McCubbin 1989).
2.3.5 Converting Operations
Converting operations transform paper into end products such as paper
towels, cardboard boxes, and typing paper. Since there is a wide variety of
paper products made by converting operations, a generalized workforce charac-
terization is not reported in the literature.
Of the 304,000 paper converting workers, 129,000 workers are estimated
to be potentially exposed to PCDDs and PCDFs based on the Bureau of Census
data from Table 2-7 and the assumption that the number of workers is propor-
tional to the amount of bleached paper produced.
2.3.6 Nonwoven Operations
Operators in the nonwoven industry are responsible for machine operation
and monitoring the system, raw material handling, quality control testing,
and general housekeeping. Operators load the pulp rolls onto the unwinder
and operate the machinery which includes the unwinder, the hammer mill, and
the product packaging and forming equipment. The newer nonwoven plants are
automated; however, the older plants may require manual feeding of the hammer
mill. Nonwoven products made from pulp are part textile and part pulp. For
the exposure calculations, PEI assumed that nonwovens are made from 50 percent
2-33
-------
pulp/50 percent textiles. The products from nonwoven operations vary from
diapers to surgical gowns, but are all treated as a single operation for this
report. Typically, there are two to four operators per shift for each finish-
ed-product machine (Nonwovens 1989). No precise information was available on
the total number of workers in the nonwoven industry; however, the number of
workers has been estimated to be more than 15,000 workers (Cunningham, 1990).
Exposures are assumed to be similar regardless of the product manufactured
(i.e., diapers, surgical gowns, etc.). Although not evaluated in this report,
a potential for worker exposure exists in the manufacture of rayon or cellulose
for use in textile fibers, filters, and food additives.
2.3.7 Commercial Users
Commercial users of paper products include almost all workers. Some
occupational classifications where workers are exposed for large portions of
their work day include lawyers, computer programmers, secretaries, account-
ants, librarians, teachers, architects, postal workers, printers, and other
government workers. Several types of paper products are utilized in various
ways which makes the workforce characterization difficult. According to
information from the Bureau of Census, over 50 million workers in the United
States have occupations which involve handling bleached paper products.
Table 2-10 presents the number of workers in each job category who may be
exposed to bleached paper products.
Medical workers who use nonwoven products containing bleached pulp
include doctors, nurses, dentists, and other workers involved in health
maintenance and diagnosing. These workers may wear nonwoven garments or
breathe through nonwoven face masks for several hours each day. Table 2-10
2-34
-------
TABLE 2-10. NUMBER OF COMMERCIAL USERS OF PAPER AND NONWOVEN PRODUCTS3
Occupation Total employed
Paper user
Managerial and professional specialty
Accountants and auditors 1,255,000
Architects 135,000
Teachers, college and university 661,000
Teachers, prekindergarten, kindergarten 3,587,000
elementary, and secondary
Librarians, archivists, and curators 219,000
Lawyers and judges 707,000
Management 18,404,000
SUBTOTAL 24,968,000
Technical, sales, and administrative support
Computer programmers 527,000
Sales representatives and workers 9,847,000
Computer operators 911,000
Secretaries, stenographers, and typists 5,004,000
Records and financial records processing 3,313,000
Duplicating and mail/message distribution 1,030,000
Miscellaneous administrative support 3,071,000
SUBTOTAL 23,703,000
Nonwovens user
Medical workers (dentists, physicians, dentists, 2,895,000
registered nurses)
TOTAL 51,566,000
a (Census 1988)
2-35
-------
presents the number of medical workers who may be exposed to bleached pulp in
nonwoven products.
Table 2-11 summarizes the overall number of workers (by industry segment
and job category) exposed to bleached pulp and paper products. These values
will be used in Section 3 for the population risk calculations.
TABLE 2-11. NUMBER OF WORKERS IN THE
PULP AND PULP PRODUCTS JOB CATEGORIES
Job category No. of workers
Pulp mill
Pulp manufacture 1,300
-Bleach operators 434
-Pulp testers 433
-Utility operators 433
Pulp drying 240
-Operators 160
-Utility workers 80
Paper mill
Paper and paperboard manufacture 32,000
-Wet-end operator 10,667
-Dry-end operator 12,445
-Utility operator 8,888
Converting operations
Paper converting operations 68,000
-General worker
Paperboard converting operations 61,000
-General worker
Nonwovens production (pulp converting) 15,000
-General worker
Commercial users
Paper and paperboard (see Table 2-10) 48,671,000
Nonwovens (see Table 2-10) 2,895,000
2-36
-------
SECTION 3
WORKER EXPOSURE
Although considerable data have been collected on concentrations of 2378
TCDD and 2378 TCDF, for pulp, sludge, and wastewaters in the pulp and paper
industry, no inhalation or dermal exposure data for 2378 TCDD and 2378 TCDF
are currently available. This is in part because of the lack of a validated
sampling and analytical method for measuring worker exposures to these chem-
icals. Furthermore, little information is available on the effectiveness of
engineering controls or the use of personal protective equipment in this
industry. PEI, therefore, had to resort to exposure modeling techniques
based on numerous assumptions in order to estimate worker exposure to 2378
TCDD and 2378 TCDF.
Pulp and paper mill workers may be exposed to 2378 TCDD and 2378 TCDF
either through dermal contact with wet or dry pulp, paper, or bleaching fil-
trates, or through inhalation of volatilized 2378 TCDD/2378 TCDF or particu-
late containing these chemicals. The source of particulates is paper dust
generated from paper cutting, rolling, or packaging operations. Mists from
the mechanical handling of wet pulp may be generated, but there is less
potential for aerosol generation in the pulp mill than there is for volatili-
zation (Sullivan 1989).
The estimates of inhalation exposures due to volatilized 2378 TCDD/2378
TCDF presented in this section are relatively low because of the low vapor
pressures of these chemicals. In addition, TCDDs/TCDFs have a tendency to
3-1
-------
preferentially bind with organic matter. No attempt was made to compensate
for 2378 TCDD/2378 TCDF affinity for organic materials.
Some exposure estimates are based on the assumption that TCDDs, TCDFs,
pulp and water mixtures have two phasesan aqueous phase and a solid or pulp
phase. Furthermore, TCDDs and TCDFs are assumed to reside only in the
aqueous portion of the mixture. The aqueous phase is assumed to consist only
of TCDDs, TCDFs, and water and is assumed to behave as an ideal solution.
Consequently, the estimates presented here represent worst-case values.
NIOSH has recently developed a sampling and analytical method for PCDDs
and PCDFs and is planning an extent-of-exposure study at 4 kraft pulp mills.
To date, NIOSH has taken five samples at one pulp and paper mill that uses
both softwood and hardwood; the sampling effort at other mills will depend on
the analytical results from the study at the first mill.
3.1 POTENTIAL FOR WORKER EXPOSURE
The potential for inhalation and dermal exposures from pulp and paper
manufacturing, converting, and nonwovens operation will vary in the industry,
depending on the worker job category, whether the process is enclosed, extent
of automation, and equipment layout.
3.1.1 Pulp Manufacture
In pulp manufacturing operations, the potential for exposure to PCDDs
and PCDFs exists primarily in the bleaching operations. In brown stock wash-
ing operations, exposure to PCDDs and PCDFs occurs if water used for these
operations is recycled paper machine white waters containing PCDDs and PCDFs
formed during bleach operations. The most common wash method, however, is
effluent from the filters and fresh hot water which are not likely to contain
PCDDs, PCDFs, or their precursors. Worker activities in brownstock
3-2
-------
operations include servicing of the brownstock washers and screens, sample
collection and testing, and general plant maintenance, which usually involves
cleanup of spills. Brown stock washers are well ventilated, with exhausts
through canopy hoods or full enclosures. These hoods are necessary to
control workplace contamination with hydrogen sulfide, methyl mercaptan,
dimethyl sulfide, and dimethyl disulfide to below regulatory limits. For
hydrogen sulfide, the acceptable Occupational Safety and Health Administra-
tion (OSHA) ceiling concentration is 20 ppm, and the acceptable OSHA maximum
peak concentration for an 8-hour shift is 10 ppm over a maximum duration of
10 minutes. For methyl mercaptan, the NIOSH recommended 15-minute ceiling
value is 0.5 ppm; the OSHA 8-hour revised Permissible Exposure Limit (PEL) is
0.5 ppm.
Most kraft pulping processes are highly automated and, consequently, the
operators spend considerable portions of each shift inside control rooms
(NIOSH 1983). In brownstock washing operations with no isolated control room
in the washer area, operators may spend essentially the entire shift in the
production area, usually at operating consoles (Soklow 1984). The percentage
of time spent in the control room ranges from 0 to 90 percent for operators,
50 to 90 percent for testers, and 30 to 40 percent for utility employees
(NIOSH 1983). Based on a NIOSH study, average times spent in the control
rooms for workers involved in brownstocking were 65 percent, 75 percent, and
33 percent for the operators, testers, and utility employees, respectively.
Since the practice of recycling white waters is rarely done in brownstock
washing operations, exposures are not estimated for workers in this area
because it is unlikely that these workers will be exposed to 2378 TCDD/2378
TCDF.
3-3
-------
The number of bleach plant workers potentially exposed to PCDDs and
PCDFs and their job descriptions depend upon the process size, degree of
automation, plant layout and equipment, and integration of bleach chemical
handling and preparation operations. Various bleaching process characteris-
tics may reduce the potential for exposure to PCDDs and PCDFs. Ventilation
of workplace areas that contain chlorine and chlorine dioxide towers,
washers, and washer filtrate tanks potentially reduce worker inhalation expo-
sure to PCDDs and PCDFs. Chlorine and chlorine dioxide towers are often
installed outdoors for greater ventilation and isolation; however, the actual
bleaching process is a closed system with limited potential for leaks.
Chlorine alarms are installed in the pulp bleaching building and usually set
to go off at 1 ppm, which is the revised OSHA Short-Term Exposure Limit
(STEL) over 15 minutes for chlorine. The revised OSHA PEL for chlorine is
0.5 ppm. These engineering controls would also limit exposure to PCDD/PCDF
vapors in the building. Rinsing operations often occur in open washers.
Consequently, the potential exists for vapor and dermal exposure. Closed
pulp conveyance systems are typically used throughout the industry in the
post-chlorination, post-hypochlorite, and post-chlorine dioxide stages.
Sampling of the wet bleached pulp or spill cleanup provides potential for
worker dermal exposure unless proper personal protective equipment is worn.
Workers can often reach into the wash stream to gather samples of bleached or
partially bleached wet pulp. The above-mentioned controls could greatly
minimize the potential for inhalation and dermal exposure to workers involved
in the bleaching process. Furthermore, worker isolation through the use of
isolated control rooms is prevalent throughout the industry. Workers are
generally provided with escape respirators in case of a chlorine leak, but
3-4
-------
typically respirators are not used in everyday bleach plant operator activi-
ties (Soklow 1984). The amount of time per shift typically spent in the
control room ranges between 75 and 90 percent for operators, 60 and 75 per-
cent for helpers, and less than 20 percent for utility workers (NIOSH 1983).
The following is an estimation of both inhalation and dermal exposures for
each pulp mill job category.
3.1.1.1 Level of Inhalation Exposure--
In the pulp mill, there are three job categories of workers (bleach
plant operators, pulp testers, and utility operators) who are potentially
exposed to PCDDs and PCDFs through inhalation. These workers spend approxi-
mately 75, 25, and 20 percent of their shifts in the control room.
In the manufacture of pulp, only vapors generated from volatilization of
the PCDDs and PCDFs constitute a potential route for inhalation exposure. No
pulp dust is generated at this point in the production process. Pulp dust
may be generated during pulp drying operations, which are discussed in the
next subsection. There are no existing data available to determine inhala-
tion exposure to 2378 TCDD/2378 TCDF vapors during pulp manufacturing. In
the absence of exposure monitoring data, PEI estimated worker exposure to
2378 TCDD/2378 TCDF using two different approaches (based on the nature of
the worker activities). The first approach utilizes a mass balance model to
estimate worker exposure for specific activities (e.g., for pulp testers
during sampling). The second approach is applicable for workers in a general
area (e.g., bleach plant operators, utility operators) and is based on
estimating the maximum 2378 TCDD/2378 TCDF air concentration available for
inhalation based on their partial pressures. These partial pressures are
calculated by assuming that TCDD, TCDF, and pulp water solutions behave as
3-5
-------
ideal mixtures. Specific details of the approaches are discussed under each
scenario for which worker exposures are estimated.
There are many mass balance models available for estimating worker expo-
sure. Table 3-1 presents some of the mass balance models (equations and so-
lutions) which can be used to estimate contaminant concentrations in confined
spaces. These models only differ by factors added to or subtracted from the
first mass balance equation in Table 3-1. The most common models used to
describe workplace contaminant concentrations are equations representing the
mass balance of a contaminant as it is generated and removed from an enclosed
space. Clement (Clement 1982) recommends using the fourth model listed for
situations with generation sources and ventilation rate. The solution of
this mass balance model can be simplified by assuming generation rate and
ventilation rate are constant and steady state is reached. Under these
conditions, the fourth equation in Table 3-1 reduces to:
C = G/kQ Equation 2
where: C = vapor concentration, g/m3
6 = generation rate, g/sec
k = mixing factor, unitless
Q = ventilation rate, m3/sec
The simplest equation describing the generation rate for a volatile
liquid (Thibodeaux 1979) is presented in Equation 3.
G = M K A (P° - P) Equation 3
R T
where: G = generation rate, g/sec
M = molecular weight, g/mole
K = gas transfer coefficient, cm/sec
A = surface area of the pure component, cm2
P° = vapor pressure of the pure component, atm
P = actual partial pressure of the vapor in the gas phase, atm
R = universal gas constant (82.05 cm3 atm/mole degrees Kelvin)
T = temperature, K
3-6
-------
0")
_J
UJ
a
o
2:
UJ
o
4^ rH
1 00
CO T-l
1/1 4->
00 C
«ac 0)
z: E
(U
O
t (
1
CO
UJ
1
co
h-
o
1
(O
3
O"
UJ
c
o
r
4_>
3
o
C
o
r
4-3
f&
3
CT
QJ
O)
O
c
to
jQ
to
(O
z:
t I CJ CO «^ Lf) VD I*"
**.^ » ^ *^^* *~-^ ^v* ^v' **
-
UJ
cr"
^ O)
> Cr
*^it. ** -^ ^^
cr -^ «
« i
1 OJ O
x O
* * ^ C^ tj~
"^ S -^.o
-_^ .^ ^. < .
11+ =»
Dfl; -r -^
*-^ ^-^ «^ f ^ ^ ^
Cr cr O S-
-^, -^ , * OT
(9 CD + ' ' '
^
+-> 1 1 4-> 4-
^-> ^ ^ 4-> -- *x
^-v > O O ^ 5» !-
> -~. O <_) > ^v. Cr
\ cr - --> cr '
cr * ** CT ^^^ ^ ^
*»<* ^^ ^- + ^« ^ ^ i
II 1 1 OJ
a)
c
o
to
-a
c
a>
Q.
a;
-o
i
i
0)
1-^
oo^-»~^ ooo .a
O O tD CD O O O
II II II II II II II
0 0 O 0 0 0 0
^^
^_>
x^^"
C3
11
O1-4-J O I-4-* C_?|4-* CJ|4-* O *-* OI4-* CJl*^ Ol+J
OTO -o|-a -o|-o -D|-O -o -a -oro -OTO -OTO
=- =» > 5» > > >
>
3-7
-------
The generation rate is a function of 1) the difference between the
equilibrium vapor pressure (P°) of the substance at ambient temperature and
the actual partial pressure (?) of the vapor present in the gas phase, 2) the
surface area of the liquid in contact with the air (A), and 3) the overall
mass transport coefficient (K). For most applications, P° is greater than P,
so G is effectively independent of the ambient gas phase concentration (i.e.,
P is negligible).
Combining Equations 2 and 3 and assuming P is negligible results in
Equation 4. Since the units in Equations 2 and 3 are different, a constant
was calculated to convert the units of Equation 4 into ppm. This factor is
333
based on converting m /sec into ft /min and g/m into ppm, and dividing by
the universal gas constant (R). The mass transfer coefficient (K) in Equa-
tion 4 varies with the intrinsic properties of the liquid and properties of
the medium into which the liquid evaporates. A typical mass transfer coeffi-
cient varies by a constant times the diffusion coefficient to some power.
Since the mass transfer coefficients (K) were not available in the literature
for 2378 TCDD and 2378 TCDF, Equation 5 was used to estimate the mass transfer
coefficients. The derivation of this equation is presented in Clement 1982.
In addition, the vapor pressure of the pure component is replaced by the
partial pressure of 2378 TCDD/2378 TCDF in the mixture. Equation 6 presents
the equation for calculating partial pressure based on Raoult's Law. The
weight fraction of the 2378 TCDD/2378 TCDF in the dry pulp is available.
However, the mole fraction of 2378 TCDD and 2378 TCDF on a wet basis is re-
quired for Equation 6.
3-8
-------
Cv . 6"3 I K * Pa Equation 4
K = 0.83 (18/M)1/3 Equation 5
Pa = P° Xa Equation 6
where Cv = concentration of 2378 TCDD/2378 TCDF in the vapor, ppm
K = gas mass transfer coefficient, cm/sec
2
A = surface area, cm
Pa = partial pressure of a component, atm
k = mixing factor, unitless
T = temperature, K
3
Q = ventilation rate, ft /min
M = molecular weight, g/g-mole
P° = vapor pressure of pure component, atm
Xa = mole fraction 2378 TCDD/2378 TCDF in the wet pulp
Exposure estimates during pulp drying are based on the assumption that
TCDDs, TCDFs, pulp and water mixtures have two phases--an aqueous phase and a
solid or pulp phase. Furthermore, TCDDs and TCDFs are assumed to reside only
in the aqueous portion of the mixture. The aqueous phase is assumed to
consist only of TCDDs, TCDFs, and water and is assumed to behave as an ideal
solution and obey Raoult's Law. It was assumed that TCDDs/TCDFs and water
are removed from the pulp at rates that ensure that relative concentrations
of these components in the ideal mixture remain constant.
The weight fraction on a dry basis for 2378 TCDD and 2378 TCDF is pres-
ent in the 104-Mill Study data. However, for the calculation of 2378 TCDD
and 2378 TCDF exposure to vapors, the mole fraction of 2378 TCDD and 2378
TCDF on a wet basis is required. There are two steps to convert from a
weight fraction on a dry basis to a mole fraction on a wet basis. The first
3-9
-------
step is to convert from a weight fraction on a dry basis to a weight fraction
on a wet basis. Based on an average pulp composition of 11 weight percent
pulp (NIOSH 1983) and the assumption that the aqueous phase contains 2378
TCDD, 2378 TCDF, and water, the weight fraction in the aqueous phase is
approximately 0.12 times the weight fraction on a dry basis. The second
conversion involves transforming the weight fraction on a wet basis to a mole
fraction on a wet basis. The mole fraction in the aqueous phase can then be
computed from a knowledge of the molecular weight of water, molecular weight
of 2378 TCDD/2378 TCDF, and the weight fraction of 2378 TCDD/2378 TCDF on a
wet basis. The mole fraction of 2378 TCDF/2378 TCDF in the aqueous phase is
thus approximately 0.06 times the weight fraction of 2378 TCDD/2378 TCDF in
the aqueous phase. Thus, the mole fraction of 2378 TCDD/2378 TCDF in the
aqueous phase is approximately 0.007 times the weight fraction of 2378
TCDD/2378 TCDF on a dry basis.
The approach for estimating worker inhalation exposure concentrations to
2378 TCDD/2378 TCDF around closed systems in the bleaching area was based on
comparison with the OSHA PEL for another chemical (chlorine) handled in the
same process area and a knowledge of the vapor pressures of chlorine and 2378
TCDD/2378 TCDF. The airborne concentrations of 2378 TCDD and 2378 TCDF were
estimated based on a comparison with the PEL for chlorine, since there are
alarms in the bleach processing area for chlorine to limit workers' exposure
to this chemical below its PEL. The use of a PEL to estimate inhalation
exposures gives a maximum or reasonable worst case workplace concentration.
The exposures for the bleach plant operator and utility operator were assumed
to be comparable since their job duties require them to be in the bleaching
area of the pulping process for a portion of the shift. Therefore, the same
3-10
-------
approach was used to estimate inhalation exposure for these job categories;
and the empirical equation for this approach is presented in Equation 7:
Po
Cv = Cvc x -p- Equation 7
where Cv = hourly concentration of 2378 TCDD/2378 TCDF, ppm
Cvc = 8-hour PEL for chlorine, ppm (0.5 ppm) (Federal Register 1989)
Po = vapor pressure of the pure component at 25 °C, atm
PC = vapor pressure of chlorine at 25 °C, atm (7.9 atm)
The inhalation exposure from volatilization for all job categories is
converted from ppm to mg/m using the equation presented in Equation 8. This
value is substituted into Equation 9 resulting in a daily inhalation exposure
(Iv) in mg/day.
It is pointed out that all the calculated inhalation exposure levels
from volatilization presented in this report are biased high because no
consideration is given to the 2378 TCDD/2378 TCDF binding with organic matter
and the presence of other chemicals in the matrices that could interfere with
the volatilization of the 2378 TCDD/2378 TCDF. No estimates could be either
found in the literature or provided by contacts in the field which would
allow for quantifying the impact of these interferences on volatilization.
Cm = Cv M/Vm Equation 8
Iv = Cm x 1.25 m3/h x ED Equation 9
o
where Cm = concentration of 2378 TCDD/2378 TCDF in the vapor, mg/m
Cv = concentration of 2378 TCDD/2378 TCDF in the vapor, ppm
M = molecular weight, g/mole
Vm = molar volume, liter/mole (24.45 liter/mole at T = 25°C
and P = 760 mm Hg)
Iv = daily inhalation exposure from volatilization, mg/day
ED = exposure duration, h/day
3-11
-------
Table 3-2A summarizes the variables and results from using Equations 4
through 6 and Equations 8 and 9 for the pulp testers. Table 3-2B summarizes
the variables and results from using Equations 7 through 9 for the bleach
plant and utility operators. The tables present estimated daily exposure to
2378 TCDD and 2378 TCDF for pulp mill workers from volatilization.
The relative toxicity of 2378 TCDF with respect to 2378 TCDD can be
determined by calculating toxicity equivalents (TEQ) for the daily exposure.
In addition, the percent exposure due to 2378 TCDD can also be calculated.
Equation 10 presents the equation for calculating TEQ, while Equation 11 is
used for calculating the percent of the exposure due to 2378 TCDD. These
equations are found in EPA 1989a. Table 3-3 presents the daily and lifetime
average daily TEQ and percent exposure due to TCDD from volatilization for
pulp mill workers.
DTEQv = !VTCDD +0.1 !VTCDF Equation 10
%TCDDv = j- J^j£ x 100 Equation 11
1VTCDD 1VTCDF
where:
DTEQv = daily toxicity equivalents from volatilization of 2378 TCDD
and 2378 TCDF
IvTCDD = daily exposure to 2378 TCDD from volatilization, mg/day
Iv,CDp = daily exposure to 2378 TCDF from volatilization, mg/day
%TCDDv = percent of the exposure from volatilization due to 2378 TCDD, %
In addition to daily TEQ, the lifetime average daily TEQ (LTEQv) for
workers was also calculated. This is presented in Equation 12:
LTEQv = DTEQv x DY x LF/(BW x LE) Equation 12
3-12
-------
TABLE 3-2A. ESTIMATED INHALATION EXPOSURE TO 2378 TCDD AND 2378 TCDF FOR
PULP TESTERS IN PULP MILLS FROM VOLATILIZATION
2378 TCDD
2378 TCDF
Variable
Low
High
Low
High
Reference
Surface area of
sampling port -
pulp tester, cm2
(A)
Vapor pressure,
atm (P°) G> 25°C
Molecular weight,
g/g-mole (M)
Mixing factor,
dimensionless (k)
Ventilation rate,
ft3/min (Q)
Temperature, K
Weight fraction of
2378 TCDD/2378
TCDF in the pulp,
for the pulp
tester dry basis
Mole fraction of
2378 TCDD/2378
TCDF wet basis
(Xa)
Gas mass transfer
coefficient,
cm/s (K)
Concentration of
2378 TCDD/2378
TCDF in the
vapor, ppm (Cv)
Exposure dura-
tion, h/day (ED)
Daily inhalation,
mg/day (Iv)
40
80
40
80
See Table 3-5
9.7xlO"13 9.7xlO"13 1.2xlO"9 1.2xlO"9 Eitzer and Hites
1986, Podoll
1986
3
i
322
0.5
,000
298
1 O ^ ^
322
0.5
3,000
298
A rwi n~*l '
306
0.5
3,000
298
> Cwin"-!-^
306
0.5
3,000
298
o cf>~'\r
EPA
See
See
See
1~9 T-,k'
1989b
Table
Table
Table
1 « O C
3-5
3-5
3-5
7.0xlO"16 3.4xlO"13 l.SxlO"15 l.SxlO"11 See Table 3-5
0.32
0.32
0.33 0.33 Calculated
-9f> ~9"\ -91 -1Q
1.2x10 " 1.2x10 " 3.9x10 " 8.1x10 iy Equation 4
1
1
1
See Table 3-5
2.0xlO"25 1.9xlO"22 6.0xlO"22 1.3xlO"17 Calculated
3-13
-------
TABLE 3-2B. ESTIMATED INHALATION EXPOSURE TO 2378 TCDD AND 2378 TCDF FOR
BLEACH AND UTILITY OPERATORS IN PULP MILLS FROM VOLATILIZATION
2378 TCDD
2378 TCDF
Variable
Low
High
Low
High
Reference
Vapor pressure
atm
(P°)
9
25
9.7xlO"13 9.7xlO"13 1.2xlO"9 1.2xlO"9 Eitzer
°C
1986,
1986
and Hites
Podol
1
Concentration of
2378 TCDD/2378
TCDF in the
vapor, ppm (Cv)
- Bleach operator 6.1x10"
- Utility operator 6.1x10"
Exposure dura-
tion, h/day (ED)
-Bleach operator 2
-Utility operator 6
Daily inhalation,
mg/day (Iv)
6.1x10"
7.7x10"}} 7.7x10"}}
7.7X10"11 7.7X10"11
2
6
2
6
2
6
iiiy/uoy uvy , ? -, ? q
-Bleach operator 2.0x10",, 2.0x10",, 2.4xlO~Q 2.4x10"
-Utility operator 6.1x10"" 6.1x10"" 7.2xlO~3 7.2x10"
Equation 7
Equation 7
See Table 3-5
See Table 3-5
Calculated
Calculated
3-14
-------
where:
LTEQv = lifetime average daily TEQ from volatilization, mg/day-kg
DTEQv - daily TEQ from volatilization, mg/day
DY = number of days per year exposed, day/year
LF = number of years of exposure per lifetime, years/lifetime
BW = average body weight for a worker, kg
LE = lifetime expectancy, days/lifetime
The number of years of exposure per lifetime (LF) was assumed to be 40
years and the lifetime expectancy (LE) was assumed to be 25,550 days (i.e.,
70 years). The average body weight for male workers (BW) is 70 kg and a
female worker is 58 kg (NCASI 1988). PEI assumed that the worker would be in
the plant for 250 days per year. Table 3-3 presents the lifetime average
daily TEQ. Table 3-4 presents the assumptions and uncertainties of those
variables used to calculate lifetime average daily TEQ from daily TEQ.
Table 3-5 presents the assumptions and uncertainties in the variables
used to calculate inhalation exposure from volatilization from wet pulp, as
presented in Table 3-2. The bleach operators, pulp testers, and utility
operators were assumed to be exposed to the PCDD and PCDF vapors during the
entire time they are not in the control room.
The following are examples of the calculation procedures used for esti-
mating levels of daily inhalation exposure to 2378 TCDD and 2378 TCDF from
volatilization. The first example is for the pulp tester using Equations 4
through 6 and Equations 8 and 9, while the second example is for the bleach
plant operator using Equations 7 through 9.
Lower limit of 2378 TCDD inhalation exposure level from volatilization for
pulp tester
Pa = 9.7 x 10"13 atm x 7.0 x 10"16
= 6.8 x 10"28 atm
3-15
-------
TABLE 3-3. ESTIMATED TOXICITY EQUIVALENTS AND PERCENT EXPOSURE DUE TO
2378 TCDD FOR PULP MILL WORKERS FROM VOLATILIZATION
Lifetime
average daily TEQ,
Daily TEQ, mg/day mg/day-kg
Job category
Bleach operators
Pulp testers
Utility operator
Low
2.4X10-10
(0.08)
e.ixio"23
(0.03)
7.3X10-10
(0.08)
High
2.4xlO"10
(0.08)
1.3xlO"18
(0.002)
7.3xlO"10
(0.08)
Low
1.4xlO"12
(0.08)
3.4xlO"25
(0.03)
4.1xlO"12
(0.08)
High
l.GxlO"12
(0.08)
8.6xlO"21
(0.002)
4.9xlO"12
(0.08)
Values in parentheses are percent exposure due to 2378 TCDD.
3-16
-------
TABLE 3-4. ASSUMPTIONS AND UNCERTAINTIES IN VARIABLES FOR CALCULATING
LIFETIME AVERAGE DAILY TEQ FROM DAILY TEQ
Uncertainty
Associated
assumption
Reasonable
possible variance
of assumption
Effects
on results
Number of days per
year workers are
exposed.
Number of years
of exposure per
lifetime.
Average body
weight of a
worker.
Lifetime expect-
ancy of a worker.
Workers were assumed
to be exposed for
250 days per year
(PEI estimate).
Workers were assumed
to be exposed for
40 years (EPA 1989a).
The average body
weight of a male
worker is 70 kg and
a female worker is
58 kg (NCASI 1988c).
Workers were assumed
to live for 70 years
(NCASI 1988c).
A maximum exposure
duration is 365
days.
Maximum of 1.5
times greater
exposure.
3-17
-------
TABLE 3-5. ASSUMPTION AND UNCERTAINTIES IN ESTIMATING INHALATION EXPOSURE TO
2378 TCDD AND 2378 TCDF FOR PULP MILL WORKERS FROM VOLATILIZATION
Uncertainty
Associated
assumption
Reasonable
possible variance
of assumption
Effects on results
The surface area
where the pulp tester
would be exposed to
2378 TCDD and 2378
TCDF.
There is not ideal
mixing of 2378 TCDD
and 2378 TCDF in
the area during
sampling.
The ventilation rate
in the area where
2378 TCDD and 2378
TCDF exposures occur
during sampling.
Temperature in the
area where the pulp
mill workers would
be exposed to 2378
TCDD/2378 TCDF.
Mole fraction of
2378 TCDD/2378 TCDF
for use in Equation 6,
The surface area
of a sample jar
ranges from
40 to 80 cm2.
The mixing fac-
tor was assumed
to be 0.5
(Drivas, Sim-
monds, and Shair
1981) for a
typical mixing
operation.
A typical venti-
lation rate is
3,000 ftVmln
(Clement 1982).
The temperature
at the bleach-
ing portion of
the process is
25°C (Soklow
1989).
Reasonable range
in the mixing
factor is 0.1 to
1.0 (Drivas,
Simmonds, and
Shair 1981).
Reasonable range
in industrial
ventilation
rates is 500 to
10,000 ft3/min
(Clement 1982).
Exposure would
range from 0.2 to
5 times the
exposure level.
Exposure would
range from 0.2 to
3.3 times the
exposure level.
At the extraction Exposure would
portion of the
pulp process the
temperature can
reach 60°C.
be 1.1 times the
exposure level
however, the
vapor pressure
would also in-
crease.
(continued)
Based on rough
approximations,
PEI computed
mole fraction of
the 2378 TCDD/
2378 TCDF in the
aqueous phase to
be equal to 0.007
times the dry
weight fraction
of the 2378 TCDD/
2378 TCDF in the
pulp. See text
for additional
information.
3-18
-------
TABLE 3-5 (continued)
Uncertainty
Associated
assumption
Reasonable
possible variance
of assumption Effects
on results
Inhalation exposure
duration for bleach
plant operator.
The duration of
the exposure was
assumed to be
2 hours since
the operator
spends the
majority of the
shift in the
control room
(NIOSH 1983).
Reasonable range
in the duration
would be 0.8 to
2 hours since
the operator
spends 75 to 90
percent of the
shift in the
control room
(NIOSH 1983).
Exposure would
range from 0.5
to 1.3 times the
exposure level.
Inhalation exposure
duration for pulp
testers.
The duration of Reasonable range Exposure would
Inhalation exposure
duration for utility
operator.
the exposure was
assumed to be 1
hour since the
worker was as-
sumed to collect
samples every 2
hours for 15
minutes during
an 8-hour shift
(NIOSH 1983).
The duration of
the exposure was
assumed to be
6 hours, since
the operator
spends the
majority of the
shift outside
the control room
(NIOSH 1983).
in the duration
would be 0.5 to
2 hours.
Reasonable range
in the duration
would be 4 to 8
hours.
range from 0.5
2 times the
exposure level.
Exposure would
range from 0.7 to
1.3 times the
exposure level.
3-19
-------
K = 0.83 x (18/322)1/3
= 0.32 cm/s
Cy = 6.3 x 105x 0.32 cm/s x 40 cm2 x 6.8 x 10"28 atm
0.5 x 3000 ftVtm'n x 298 °K
= 1.2 x 10"26 ppm
rm 1.2 x 10"26 x 322
Cm- 205
= 1.6 x 10"25 mg/m3
Iv = 1.6 x 10"25 mg/m3 x 1.25 m3/h x 1 h/day
= 2.0 x 10"25 mg/day
Lower limit of 2378 TCDD inhalation exposure level from volatilization for
bleach plant operators
Cv . o.5 ppm x
= 6.1 x 10"14 ppm
-14 322
Cm = 6.1 x 10 ppm x ^ ^
= 8.1 x 10"13 mg/m3
Iv = 8.1 x 10"13 mg/m3 x 1.25 m3/h x 2 h/day
= 2.0 x 10"12 mg/day
The following is an example of the calculation procedure (Equations 10
and 11} for estimating TEQ daily exposure and percent daily exposure due to
TCDD for pulp mill workers from volatilization from wet pulp.
3-20
-------
Lower limit for TEQ dally exposure and percent daily exposure due to TCDD for
bleach plant operators from volatilization
DTEQv = 2.0 x 10"12 mg/day + (0.1 x 2.4 x 10"9 mg/day)
= 2.4 x 10"10 mg/day
%TCDDv = 2.0 x 10"12 mg/day/(2.0 x 10"12 mg/day + 2.4 x 10"9 mg/day) x 100
= 0.08%
The following is an example of the calculation procedure using Equation
12 for estimating lifetime average daily TEQ.
Lower IJmit for lifetime average daily TEQ to bleach plant operators from
volatilization
LTEQv = (3.0 x 10"11 mg/day x 250 days/yr x 40 years/lifetime)/
(70 kg x 25,550 days/lifetime)
= 1.7 x 10"13 mg/day-kg
3.1.1.2 Level of Dermal Exposure--
Dermal exposure levels to 2378 TCDD and 2378 TCDF were computed based on
the assumption that workers do not wear any type of gloves that effectively
limit exposure to PCDDs and PCDFs. However, in actual practice, some opera-
tors may wear chemical-resistant gloves during the handling of the pulp.
Since the type of glove used, the extent of glove use, and the frequency of
glove replacement could not be determined, consideration in the estimation of
dermal exposure could not be given to the degree of protection provided by
personal protective equipment.
There are a few different approaches available for estimating dermal
exposure. The approach used was that agreed upon by EPA, the Federal Drug
Administration, and the Consumer Product Safety Commission (EPA 1989b) for
use in this project. This approach considers the partitioning of PCDD/PCDF
from the appropriate matrix (e.g., soil, sludges, paper) to a liquid (i.e.,
3-21
-------
water, skin oils, urine, blood) and percutaneous absorption of PCDDs and
PCDFs from the liquid. In this reference, common assumptions for the as-
sessment of dermal exposure are presented; however, equations for estimating
dermal exposures were not provided. CPSC supplied three equations to PEI for
estimating dermal exposure (CPSC 1989); these equations are for estimating
dermal exposure to pulp, paper, and sludge/soil. The equation for handling
wet pulp was selected and is presented in Equation 13.
DEW = DC (ppt) x p (mg/cm3) x FT (cm) x | x AD (h"1) x S (cm2) x
ED (h/day) Equation 13
where:
DEW = dermal exposure from handling wet pulp, mg/day
DC = 2378 TCDD/2378 TCDF concentration in the wet pulp, ppt
p = density of the wet pulp, mg/cm3
FT = liquid film thickness, cm
K = liquid equilibrium partition coefficient of TCDD and TCDF from
water, unitless
AD = absorption coefficient of TCDD/TCDF through the skin, h
S = skin surface area, cm2
ED = exposure duration, h/day
The concentrations reported in the 104 Mill Study for 2378 TCDD and 2378
TCDF were based on dry weight fraction; however, a wet weight fraction for
2378 TCDD and 2378 TCDF was needed for Equation 13. Based on an average pulp
composition of 11 weight percent pulp (NIOSH 1983) and the assumption that
the aqueous phase contains 2378 TCDD/2378 TCDF and water, the weight fraction
in the aqueous phase is 0.12 times the weight fraction on a dry basis.
The bleach plant operator was assumed to spend approximately 75 percent
of his shift in the control room which corresponds to 6 hours. The operator
leaves the control room to inspect equipment, occasionally collect samples
3-22
-------
(typically done by pulp testers), routinely clean up spills, supervise equip-
ment startup and shutdown, and supervise maintenance operations. The major
responsibility of this operator is to supervise the pulp mill operation. The
density for pulp is assumed to be 1000 mg/cm3 and a 2378 TCDD/2378 TCDF
liquid film thickness was estimated to be 0.25 mm. Dermal exposure duration
was assumed to equal the amount of time the operator spends outside the
control room.
The pulp testers spend approximately 75 percent of their shift outside
the control room which corresponds to 6 hours. The worker leaves the control
room to collect and analyze samples and inspect equipment. Sample collection
and testing was assumed to occur for 15 minutes every 2 hours. The range of
the dermal exposure duration was based on the time for sampling and analysis
and the amount of time the operator spends outside the control room.
The utility operators spend approximately 75 percent of their shift in
the bleach plant which corresponds to 6 hours. The utility operator is
responsible for cleaning the plant, any spills from the conveyor, and the
wash stock from washers and refiners. Dermal exposure duration was based on
the time the operator spends outside the control room.
Table 3-6 summarizes the variables and results for dermal exposure for
bleach plant operators, pulp testers, utility operators in pulp mills. The
relative toxicity of 2378 TCDF with respect to 2378 TCDD can be determined by
calculating TEQ. The percent exposure due to 2378 TCDD can also be calcu-
lated. Equations 10 and 11 are used to calculate these two variables. In
these two equations, the daily inhalation exposure from volatilization (Iv)
for 2378 TCDD and 2378 TCDF are replaced with the daily dermal exposure (DEW)
for 2378 TCDD and 2378 TCDF. Table 3-7 presents the daily and lifetime
3-23
-------
TABLE 3-6. ESTIMATED DERMAL EXPOSURE TO 2378 TCDD AND 2378 TCDF FOR
FOR PULP MILL WORKERS
2378 TCDD
Variable
2378 TCDD/2378 TCDF
concentration of
wet pulp, wet
basis, ppt (DC)
Density of the
pulp, mg/cm3 (p)
Liquid film thick-
ness of the
pulp, cm (FT)
Liquid equilibrium
partition coef-
ficient of TCDD/
TCDF from water,
unitless (K)
Absorption coef-
ficient of PCDD/
PCDF through the
skin, h"1 (AD)
Skin surface
area, cm2 (S)
- Bleach
operator
- Pulp testers
- Utility
operators
Exposure dura-
tion, h/day (ED)
- Bleach
operators
- Pulp testers
- Utility
operators
Dermal exposure,
ing/day (DEW)
- Bleach 1
operator
- Pulp testers 1
- Utility 2
operators
Low
0.012
1000
0.025
13,000
0.012
250
650
1300
2
6
6
.4xlO"16
lxlO'15
.2xlO"15>
High
5.88
1000
0.025
13,000
0.012
300
650
1300
2
6
6
S.lxlO"14
5.3xlO~J2
2378 TCDF
Low
0.03
1000
0.025
29,000
0.012
250
650
1300
2
6
6
1.6X10'16
1.2xlO"J5
2.4X10"15
High Reference
314 See Table 3-8
1000 See Table 3-8
0.025 See Table 3-8
29,000 EPA 1989c
0.012 EPA 1989c
300 See Table 3-8
650 See Table 3-8
1300 See Table 3-8
2 See Table 3-8
6 See Table 3-8
6 See Table 3-8
2.0xlO"12 Calculated
1.3x10"}} Calculated
2.5X10"11 Calculated
3-24
-------
TABLE 3-7. ESTIMATED TOXICITY EQUIVALENTS AND PERCENT EXPOSURE DUE TO
2378 TCDD FOR PULP MILL WORKERS FROM DERMAL EXPOSURE
Parameter
Bleach operators
Pulp testers
Utility operator
Daily TEQ
Low
1.5xlO'16
(47)
1.2xlO"15
(47)
2.4xlO"15
(47)
,a mg/day
High
2.8xlO"13
(4)
l.SxlO"12
(4)
3.6xlO"12
(4)
Lifetime
average daily
TEQ,a mg/day-kg
Low
8.6xlO"19
(47)
6.7xlO-18
(47)
1.3xlO"17
(47)
High
1.9xlO"15
(4)
1.2xlO"14
(4)
2.4xlO"14
(4)
Values in parentheses are percent exposure to 2378 TCDD.
3-25
-------
average daily TEQ and percent exposure due to 2378 TCDD from dermal exposure
to wet pulp for pulp mill workers. Table 3-8 presents the assumptions and
uncertainties in the variables used to calculate the dermal exposures for
pulp mill workers in Table 3-6.
The following is an example of the calculation procedure (Equation 13)
used for estimating levels of daily dermal exposure for pulp mill workers
potentially exposed to TCDDs and TCDFs in the handling of wet pulp. Lower
limit of 2378 TCDD dermal exposure level for the bleach plant operator is
computed as follows:
DEW
= 1.1 x 10"14 x 1000 mg/cm3 x 0.025 cm /13.000 x 0.012 h"1 x
250 cm2 x 2 h/day
= 1.3 x 10"16 rug/day
3.1.2 Pulp Drying
3.1.2.1 Level of Inhalation Exposure--
Inhalation is one route of exposure to PCDDs and PCDFs in pulp-drying
operations. During drying of the pulp, vapors are released into the air. It
is estimated that the pulp-drying and utility operators may be exposed to
PCDDs and PCDFs by inhalation for 2-hours during their shift because their
job activities are conducted away from the drying machines for a majority of
the shift. The method for estimating inhalation exposure from volatilization
for this open operation is based on the maximum partial pressure of 2378 TCDD
and 2378 TCDF computed using the ideal gas law. This is a worst-case approach.
In this approach, it is assumed that 2378 TCDD and 2378 TCDF are in an ideal
solution with water. Pulp was assumed to be a separate solid phase. This
approach assumes that the relative amounts of 2378 TCDD/2378 TCDF and water
3-26
-------
o
1
LU
rv
~~~*
oo
O
Q.
X
Ll 1
LLJ
_J
^T
2:00
fy e£
LU LU
Q ^
o:
CO O
Z 3
HH
H* *
CM
oo
oo
"*
.
CO
1
co
LU
i
CQ
a:
i
CO
4J
r
3
CO
(U
t-
o
{/)
4-*
0
QJ
M-
LU
<*^ E
C 3
o a; to
CO i CO
to ^^ to
01 °*~
a: co M-
co O
o
a.
o c
r-
fO 4->
i- Q.
0 E
O 3
CO CO
CO CO
CC 03
>^
^>
C
^
re
^_>
s-
01
o
c
^
to CO
01 01 QJ QJ QJ
CD E * CD E * CD I/)
C'l-r c.,-, COJi
to 4^ 01 ro +-> O) n3 £ S- > S- -r- >
r-4 01 O ^ +^ 01
"O r~ T3 f-* X) ^
1^-1 I r-t 1 C\J
3d) 3 0) 3 cno a>4-o o
i- a. j_ . Q. s_ o.
3OX -3OX 3LOX
co a) co 01 co 01
o E o E o E
Q.OO) O.OO) Q.OOI
Xi-.C X S- _C X S- ^=
LU 4- -t-> UJ H- -(-> LU>t--4->
CD Of JZ O
CM 1 C O +J * O
c d) «"H CJ" o re ^> o ^ re co
OCD' r-E3' - >+_ i J2 U O) «^-»
r- re o - i o CM s- i re i- i i CM
i->-t->+->c«o s-co sreojareco
recoco t-l*-Ecri COT-+-> OCTi
t.ocr> o E i i -t-> x> a> 4-> i i
+-> CDt i » i if-'o ccaicu
cc ai LO s_ T-a>s-rerea>M-
01 ! CH COCDCMre i^ 4-* 3 *4 CO 1-
o.ccvco toc'to too«/>4->i-reo
coajo aireos- o-ocsai-o
ores' ci-o) -ao-ocoi-c
O 0) 4-^ ^^* ^x Q ^> ^ XJ X i- O QJ
i oai+-> co i aj 4- c c a.
CXX)^ 'i > "O O 3 * '> 'f~ O
i +j ^:reEc CL o 01 ^: Q-
3O)coc: -i->i:Ere XOTDCOCOXJ
Q..C ai a> a> 3 13 i
+>>- o ECO> ico rei crea) T--I-.CTI .c s- c ^: i so
I re>cx LL. 3 o i H-re-i-
>, 01 4-> 1 i
o-co j= >, cc OILU surec
3ooo -Of re-r-**-s- co. re o-»-»rcs-co^$-o
Q.CM »re >>-t->oc3 res <4->>co (ure-coOM-
&-aire3re -MC3 SE i-xjre^~ai- c<4- «
+->i«-a>cocr -i- o i >> 3 c a> -a PJ ~
co-«->reca>c co o-t->«n COLO coxJEM-re^-oEaiNEo
01 (O.CO O CXJco-i-E COCM OJi O ^(OOtogtJCO
OOJSQ.CM i
^> 01 C 3 "H" CD *r~ to f> 3 "O O 01 CO "p** 4 O ^" QJ CO C QJ LO CO
coreo-i->4-> EO.CM -"-^ »-> o re j= re CM i <
f-H QJ 01 o co o o xj cxr** .c X? co tj QJ ^ 01 01 *o oo
f~4 t- CO 3 re QJ re *^^ QJ 4-* r~ 4^ O QJ QJ ^^ I- ^ g (^ ^ j/^ ^ ^f
cxr^crs-ES-co CDEC3O +-> co O3i +->4->-h--'-reo
CfOreM-'i-tt-'r- E3OIQ. E OCOOCO C C Z
o QJ CM 4-> co coo o i ~o ex re i i ajcai QJCO v
.c ai4-> -»->re otos_re4->« -r-aj xs i-.toa>E»oa;
o 4-> »-x: .c to .c xi CD re QJ - 4-E QJ QJOICOOJOJ corei to
QJ O4->CD-r-CD O D-.C CO O 3 reXJCD"Oi-Sre"Dt+-reQJ
COT3Q 'i-COT-4-> t-4CO 4->VOCn QJCO QJQJ CCCX4-> Cl-Ef
recocajreojoj re i i -i- . en .ceo x:i-o-r-reQjajcj-re3ajre
corei -I-S-QS5 «CS«-iSOi-i 1 re i re4J«4_^;i.^ao.cco4-E
CO
*r
00 co Q.
t»« re i QJ 4->
co x> 3 co j= re c
CM a. co 4-> QJ re
4-> QJ S- i t3
4-QJ 4-> CC reO-C
os co -^ o QJ re
S O -i- Q. O O Q
OLL. QJ jz r rerexJQ
i-Q .C 4J3 C|_o)i O
4->O 4-> Q. S- i 3 K
0| E 3 J3 O
re i»- r +-> co s o
i- OO O -i 01 QJ 4->
*t- 1**- 't- s c j= s-
CO >, -r- 4-» O XJ
.c ^^ -i «t .c co QJ re co
CDQ' . co 3+->C S_ S- O LL.
^" O CJ C O" *^ QJ QJ QJ O- Q
QJOO QJ -i M .^ JC£Q.XCJ
31 Q -JOCO » SOQJI
(U
c
o
(J
3-27
-------
^~^
o
d)
3
C
r-
4^
C
o
u
CO
1
CO
UJ
fm J
CO
1
QJ
0
c
to
d) T-
r L.
J3 03
03 >
C
0 d>
CO l
03 -Ct
dl T-
C£ CO
CO
o
CL
"^
d>
4->
n3
r
U
O
10
to
^
3
to
d)
S-
c
o
to
4-*
u
dl
C|-
UJ
c
o
r
4-)
CL
E
to
«n
to
t-
O
C
o
^
4»>
CL
E
3
to
to
Iti
2^)
4-3
C
r
to
+J
S-
dl
u
c
~*^
dl
en
C r
03 to dl
J- dl >
E d)
XJ <-
i 4->
3 dl
O CM l-
]j 3
O CO
dl 4-» O
t- CL
3 f~* X
CO dl
0 E
Q. O dl
X i- -C
dl f
O 4->
re >> O
IK- r~ *"** *^
i- r- U
13 fO O fO
(/) »r_ +j ^"i
+J
C C dl TJ
i- dl i. C
vx 4_> 3 fO
co O to
CL o 4->
o CL c
dl -0 X O
tO i dl S-
O 3 M-
CL O dl^
X 0 -0
dl 3 to
(O r T3
dl dl O C
X: S- C 03
^ o3 *r ^
*-^ "O
dl LU C
o Q- re QJ
re (J
<+- >>4-> 10
S_ X) C 4_
3 O S-
in -o s- 3
dl *^ (/I
C 4-> ** -*
i- (O C
^ E ^3 "*""
CO *" C* ^
4-> eo co
O to .c
dl dl dl
in di .c
O CO C 1
CL re o
X 2
d) dl *-
O3 -Q -i£
dl dl O
x: J- 0 03
1 rO 4-> X>
to
(0 S-
dl dl
^ 4-3 O
03 CO 4->
dl
dl 4-> "X3
U O)
re CL to
it- i O Li_
S_ 3 CLO
3 CL X O
CO dl (
d)
C .C dl -O
-^ re
(/) dl "D
S- r 0
dl dl 3 O
^ -e o o
f S S h
o
T3 OO
O) *- *
t- i"-l CNJ
(0 00
o cr>
dl 4-> i-H
o
n3 dl ^^
*«- to i.
i- 03 O
3 dl T3
to s_ c
U d)
i- -r- O
-* Cu
to T3 -
^»
d) 3 M
f O E
H- S 0
d)
C
o--»
CSJ
J-CO
O CTi
^r~ i^
M C|_
£ i-
O O
"O
0 C
LO OJ
^O O
o
CO Q.
03 -O
dl C
S- 03
re .c
d) dl
cn E *
C !- r
rtJ 4-> dl
S- >
O dl
T3 r
r CVJ
3 dl
O O S-
to
dl O O
i. ' Q.
3 "* X
to d)
o E
CL O QJ
X i. ^
L±J *+ 4-*
d> f
U 4-»
*f 1 ~ ^
S- r
3 (O O
to *^~ 4^
4^
C C dl
- d> i-
in O co
CL o
o CL
d) T3 X
in i di
O 3
CL O QJ
X U T3
d) 3
fl3 i
di d) u
j= s_ c:
K (0 *^
( H
dl LU
O Q- 4->
03 C
C|- >, 0
L- !_Q (_
3 S-
tO T3
QJ
f" ^J (/)
r- *O "O
^ £ C
(/) *r~ fO
+-* i^
"O 01
OJ OJ J=
t/1) ^^
^D ^0 ^5
CL re J3
X 2
03 X)
d) dl
J= 1- O
1 (O 4->
1
s_
CO d> T3
dl CL d)
^ O to
ro o
^ ^
*^
U
03 dl
f^ C"
4^)
T3
C O
4-> d)
C S_
O 3
s- to
M- 0
^-^ CL
X
in di
o
C TJ
03 C
^ 03
«M
E
u
o
c <^
r- CO
^^ M
w 1-*
QJ t/)
,g" »n"
^_
fO
dl
s-
^"^ fO
t^/
U dl
re u
q-
T3 S-
C 3
re to
1
i_
3
i/)
c
.»
^^
(/>
QJ
.c
h-
CO
03
dl
t-
o
t^
c^
1.
o
"^3
C
dl
CL
O
SM<*
^J
C
ro
ft
di
c
s-
o
d)
to 4-
03 S-
dl O
i- "O
o c
C QJ
^ ^L
o
a a.
3
O M
2 E
u
«3
dl O
i- O
re co
d) CM CM
u oo
03 o cr>
,m«t
ro
co
CTl
>> CL
d) 4-> X
O -r- d)
(O r
S- 4-> J3
3 3
in "O
dl r
C .C 3
r~ 4«) O
^ S
10 dl
i- S-
dl dl O
.C .C 4->
1 5
O d>
T3 r-
^ dl
o o s-
tn
di ^± O
S- Q.
3 O X
CO dl
O E
CL O dl
l2ct 5
dl
_c
4^ CO
. dl
*r~ | *
dl
a> _a QJ
C71 O
C "O C
(O i -i-
i- 3 in
0
di 2 to
S C 3
03 O O
0 4J
to re CM
ra S-
d) 3 O
1
X
dl O
4-> dl
dl f
-C -O 4->
4-> dl
E d)
o to c
in !-
c re to
o
r- CO CO
4^ re ^-
03 2 3
S- O
3 QJ x:
3 CM
dl CO
-C O QJ
r CLJO
c
O
r"
4->
re 4->
i- C
3 re
0 r
CL
d)
i- J=
3 U
in ro
O d)
Cvi
X J3
dl S-
dl O
r ^* 4^
re 4-> re
E s-
C t- di
QJ O CL
0 H- O
dl
O 4J
4J
C
^^
4->
to c^_
^3 *r
c x:
di to
CL E
to di O
r- Q
S_ 4-> S-
o
re o 'o
s- s-
QJ ^e 4->
cuo c
u
j '
1 H- 1
X - 5- E
OJ= 33
S- CO T3 E
§*^
dl X
re x: o x: re
4«) ff L^ ^
in
T3 4- i dl
coo x:
d) %~-~~ 4->
CLV« 4-> CO
to LO c oo di
^* O CTl f-
J- (J >-H re
0 >,
4-> f dl 31 in
i. 4-> 4-> O O
di re i -i-
CL E C Z 4->
O *f~ *r ^^^* rO
di
i-
dl 1
S T> >, C
dl dl O
co in x: o
S- O 4->
O CL di
4^ X d) ^
re di E ^
S- !-
dl dl 4-> dl
O dl -
o x: co
dl 4~* 4^ 4~^ E
x: 3 o
4-> T3 r O O
dl r S-
O 3 C r
C CO S- dl O
r- CO O O- S-
cn re <+- co 4-»
-o
d>
C
O
(J
3-28
-------
o
OJ
3
C
+J
C
o
(J
GO
1
CO
LU
_J
CO
<£
I
CO
4-J
r
3
CO
OJ
s_
c
o
CO
4_>
o
QJ
4-
LU
OJ
U
^ ^
03 O
QJ - !-
r i. 4->
JO 03 Q.
03 > E
C 3
O QJ CO
CO r CO
03 JO 03
QJ -r-
o: co 4-
CO O
o
o.
T3 C
OJ O
4-* *^
03 4->
i- Q.
U E
O 3
CO CO
CO CO
CC 10
>n
+J
c
*Jo
*4-*
J-
QJ
(J
r-
=3
CO
OJ QJ
CT> E
C - r
03 4-> OJ
J. >
«3- QJ
"O ^~
i i I
3 OJ
O O S-
5 -t-> 3
CO
QJ 1^ O
S- D.
3 O X
CO OJ
O E
Q. O OJ
X i- J=
LU 4- 4J
OJ
J= O
4-> 4->
C -ej-
*~ QJ
OJ JO
CD
c -o
03 r-
S- 3
O
OJ 2
^~
JO C
03 O CO
C - S-
O-4->3
CO 03 O
(O t ^C
OJ 3
QC T3 00
OJ 1 O 1 OJ OJ
1 JO 03 O 03 S_ -O
X i. i- i. OJ -r-
OJ O OJ OJ 3 E S "O CO
t-) O-J= i -O 3 QJ !->
QJ O-4->O ECOC03
JEt3 l_OJ'.-i_OO
*-" cj^'S'^f X5 x'oj E
C)_34J O£«30JEO
O CO &« 0 t- -i- O
oo a> in QJ oj a) -t-> t-
C 03 U C\J QJ^-NJZ Q.J3
O C J=CO-»->O QJi
i-CO'(-CO-t->00 OJZO
+^ n3 CO "O O> OJ QJ 4^ 4^ S»
(05 CCrHl_J= 4J
L. COOJ1'- n34->"O*f-C
3QJS-Q. a: OJ o o
OS-3C04->1/OCOOJ£ O
3O <+-OCCJ3S^
OJCOJZS-'»-> iQCCOOOJ
JCO OJCZ'i-'i-cOOJC
h Q.VD 4-> 4-» CO n3 i 4->
a.
OJ *3
s- a.
3
co i.
O O
X
OJ C
O CO
- J.
(O 4J QJ
E
S- CO
OJ 3 OJ
Q -O !->
CO
QJ OJ
cn E
C V- 1
ro 4-> OJ
^ >
*^ OJ
-o
I I 1
3 QJ
o o s-
5 +-> 3
CO
QJ r*. o
t- Q.
3 O X
CO QJ
o E
a. o oj
X S- J=
UJ H- +J
OJ
J= O
4-> 4J
C «3"
*~ QJ
OJ JO
a>
c ~o
03 r
i- 3
0
OJ 3. CO
i-
JO C 3
03 O O
C «- JZ
O 4->
CO 03 00
03 S_
OJ 3 O
ac-o 4->
QJ i CO 1 QJ E
1 JO 1 OJ OJ CO 03 OJ E O
x J- 4-> j= cn t-jo-r-o
aioajo34->f-iaja) +-> j_
QJ O'--C3I4->O4->QJr
4->QJQJOI~OQJQJ-O4->J-
4- 3 4-> Q.4- Z 03 4-> E ««- C
O CO Q.-t-N 3 O O
co QJ O3 J^ CO QJ CO O
C 03 O CO E C O CO 3-e
O Ceo OOC03OQJ
i- CO -i- T3 OJ O 'i- -i- O J=
4->03COCJCl-4->COQJi-i4->
03 3 QJ 4-> 03 S-
S- co CL i i- E QJ "O QJ
3QJUcO -i-COOcO
J=O 4->OOJ=o3OX3
1 Q.VO OSCMOt E4JQJO
1 *
>r_
OJ +J
l_ 3
3
CO J-
0 0
X
OJ C l-
o o
03 4-> 03
E 03 t-
i- J- QJ
OJ 3 Q.
Q -a o
3-29
-------
remain constant throughout the drying phase. The partial pressure of 2378
TCDD and 2378 TCDF are calculated using Equation 6. The ideal gas law
equation is presented in Equation 14. This equation transforms into Equation
15 by solving the right-hand side of the equation for moles per volume (m)
and then multiplying both sides of the equation by the molecular weight to
obtain the inhalation exposure concentration of 2378 TCDD/2378 TCDF.
PxV=nxRxT Equation 14
Cm = Mxy=Mx^p xlxlO6 Equation 15
where: P = partial pressure of 2378 TCDD/2378 TCDF, atm
V = volume of the gas, m3
n = number of moles, moles
R = ideal gas constant, atm. liter/mole.K (0.0821)
T = temperature of the gas, K
Cm = concentration of 2378 TCDD/2378 TCDF in the vapor, mg/m3
M = molecular weight, g/mole
3
The inhalation exposure concentration in mg/m based on the ideal gas
law is then substituted into Equation 9 resulting in a daily inhalation
exposure (Iv) in mg/day. Table 3-9 summarizes the variables used to calcu-
late inhalation exposure levels for pulp-drying and utility operators from
volatilization from wet pulp and presents exposure estimates.
The relative toxicity of 2378 TCDF with respect to 2378 TCDD can be
determined by calculating TEQ values. The percent exposure due to 2378 TCDD
can also be calculated. Using Equations 10 and 11, these two variables are
calculated. Table 3-10 presents the daily and lifetime average daily TEQ and
percent exposure due to 2378 TCDD from volatilization from wet pulp for
pulp-drying operators. Table 3-11 presents the assumptions and uncertainties
in the variables used to calculate the daily exposure for the pulp-drying
operators from volatilization.
3-30
-------
TABLE 3-9. ESTIMATED INHALATION EXPOSURE TO 2378 TCDD and 2378 TCDF
FOR PULP DRYING WORKERS FROM VOLATILIZATION
Variable
Vapor pressure,
atm (P°) @ 71°C
Weight fraction of
2378 TCDD/2378
TCDF in the wet
pulp, dry basis
2378 TCDD
Low High
1.6xlO"9 1.6xlO"9
O.lxlO"12 4.9xlO~U
2378
Low
2.0xlO"6
2.5xlO"13
TCDF
High
2.0xlO"6
2.62xlO"9
Reference
Schroy 1984,
See Table 3-11
Table 2-5 104-
Mill Study
data
Mole fraction of
2378 TCDD/2378
TCDF (Xa), wet
basis
Partial pressure
of 2378 TCDD/
2378 TCDF, atm
(P)
Molecular weight,
g/g-mole (M)
7.0x10
-16
1.1x10
-24
322
Ideal gas constant, 0.0821
atm liter/g-mole
°K
Temperature, °K (T) 298
Concentration of 1.5x10"
2378 TCDD/2378
TCDF in the
vapor, mg/m3
(Cm)
Exposure dura-
tion, h/day (ED)
- Pulp-drying 2
operators
- Utility 2
operators
Daily inhalation,
nig/day (Iv)
- Pulp-drying 3.7x10
operators
- Utility opera- 3.7x10
tors
-17
-17
3.4x10
-13
5.5x10
-22
1.8xlO"15 l.SxlO"11
3.5xlO"21 3.7xlO"17
See Table 3-5
Calculated
322
0.0821
7.2X10
306 306
0.0821 0.0821
298 4 2981Q
4.4x10 ^ 4.6x10 iu
EPA 1989b
Felder 1978
See Table 3-11
Calculated
1.8x10
1.8x10
2
2
-14
-14
2
2
2
2
l.lxlO"13 l.lxlO"9
l.lxlO'13 l.lxlO"9
See Table 3-11
See Table 3-11
Calculated
Calculated
3-31
-------
TABLE 3-10. ESTIMATED TOXICITY EQUIVALENTS AND PERCENT EXPOSURE DUE
TO 2378 TCDD FOR PULP DRYING WORKERS FROM VOLATILIZATION
Lifetime
/erage da-
Daily TEQ,d mg/day TEQ, mg/day-kg
Job category
Pulp-drying operator
Utility operator
Low
l.lxlO"14
(0.03)
l.lxlO"14
(0.03)
High
l.lxlO-10
(0.002)
l.lxlO-10
(0.002)
Low
e.ixio'17
(0.03)
6.1xlO'17
(0.03)
High
7.7xlO'13
(0.002)
7.7xlO'13
(0.002)
a Values in parentheses are percent exposure to 2378 TCDD.
3-32
-------
TABLE 3-11. ASSUMPTION AND UNCERTAINTIES IN ESTIMATING INHALATION EXPOSURE TO
2378 TCDD AND 2378 TCDF FOR PAPER MILL WORKERS FROM VOLATILIZATION
Uncertainty
Associated
assumption
Reasonable
possible variance
of assumption Effects
on results
Vapor pressure for
2378 TCDF at 71°C
was not found in
literature.
Temperature that the
pulp/paper drying
occurs.
Temperature of the
air which contains
2378 TCDD/2378 TCDF.
Inhalation exposure
duration for pulp-
drying operator.
Inhalation exposure
duration for pulp-
drying utility
operator.
The vapor pres-
sure for 2378
TCDD from 25 to
71°C increased
from 9.7 x 10"13
to 1.6 x 10"9
atm. Using the
same increase in
vapor presure as
2378 TCDD, the
vapor pressure
of 2378 TCDF
from 25 to 71°C
would increase
from 1.2 x 10"9
to 2.6 x 10"6
atm.
The temperature
would be approx-
imately 70°C
(Grant 1989.)
The temperature
would be approx-
imately 25°C when
the vapors would
be inhaled by the
worker.
The duration of
the exposure was
assumed to be 2
hours, since the
operator spends a
majority of the
shift away from
the drying ma-
chine.
The duration of
the exposure was
assumed to be 2
hours since the
operator spends
majority of the
shift away from
the drying ma-
chine.
Reasonable range
in the duration
would be 1 to 4
hours.
Exposure would
range from 0.5
to 2 times the
exposure level.
Reasonable range
in the duration
would be 1 to 6
hours.
Exposure would
range from 0.5
to 3 times the
exposure level.
3-33
-------
The following is an example of the calculation procedure (Equations 6,
15, and 9) used for estimating levels of daily inhalation exposure for pulp
mill drying operators potentially exposed to 2378 TCDD/2378 TCDF from vola-
tilization of wet pulp.
Lower limit of 2378 TCDD inhalation exposure level from volatilization
for pulp operate"??
Pa = Pa° x X,
a
= 1.6 x 10"9 atm x 7.0 x 10"16 (at 71°C)
= 1.1 x 10~24 atm
_24
Cm = 322 g/g-mole x 0 0821 atm ?iterx298 K x 100° 1iter/m x 100°
g-mole K°
= 1.5 x 10"17 mg/m3
Iv = 1.5 x 10"17 mg/m3 x 1.25 m3/h x 2 h/day
= 3.7 x 10"17 mg/day
Pulp dust may be generated during the pulp-drying and -handling opera-
tions, but actual dust concentration levels have not been measured (McCubbin
1989).
3.1.2.2 Level of Dermal Exposure-
Workers in the pulp-drying operations are potentially exposed to PCDDs
and PCDFs through dermal contact with the wet or dry pulp. Dermal exposure
may occur during pulp sheet weighing when sheets are added or removed by hand
to achieve a predetermined weight. Fork-truck drivers usually do not handle
the dry pulp. Dermal exposure to the wet or dry pulp is possible for the
utility workers if personal protective equipment is not worn.
Dermal exposures to PCDDs and PCDFs were based on the worst-case assump-
tion that pulp-drying workers do not wear any type of gloves that effectively
limits exposure to PCDDs and PCDFs. Pulp-drying operators are potentially
exposed to PCDDs and PCDFs while handling the dry pulp sheets during weighing
3-34
-------
operations. This is similar to the handling of dry paper; therefore, the
equation for handling paper was selected for the pulp-drying workers. Dermal
exposure from handling dry paper or pulp is presented in Equation 16 (CPSC
1989).
DED (nig/day) = DC (ppt) x PW (g) / PS (cm2) x R (h"1) x %AD x S (cm2) x
ED (h/day) Equation 16
where DED = dermal exposure from handling dry material, mg/day
DC = 2378 TCDD/2378 TCDF concentration in the dry pulp, ppt
PW = weight of the dry pulp sheets, g
PS = surface area of the dry pulp sheets, cm2 _.
R = rate of transfer from pulp to the skin, h"
%AD = percent 2378 TCDD/2378 TCDF available for dermal absorption;
fractional value used in calculations
S = skin surface area, cm2
ED = exposure duration, h/day
Dermal exposure duration was based on engineering judgment. It was
assumed that only the palms and fingers of both hands of the pulp drying
operator are in contact with the dry pulp sheets. Table 3-12 summarizes the
variables and results for dermal exposure for the pulp-drying operator.
The following is an example of the calculation procedure used for esti-
mating levels of dermal exposure for the pulp-drying operator potentially
exposed to TCDDs and TCDFs in the handling of dry pulp; the lower limit of
exposure to 2378 TCDD is used in the example:
DED = 0.1 x 10~12 | x 454 g/6000 cm2 x 0.0005 h"1 x 0.25 x 250 cm2 x 2 h/day
x 1000 mg/g
= 4.7 x 10"13 mg/day
Utility workers who handle the wet and dry pulp during cleanup of the
production area were assumed to come into contact with the pulp 2 hours per
day. The worst-case assumption that the workers do not wear any type of
glove that effectively limits exposure to PCDDs and PCDFs was also used in
3-35
-------
TABLE 3-12. ESTIMATED DERMAL EXPOSURE TO 2378 TCDD AND 2378 TCDF
FOR PULP DRYING OPERATORS
2378 TCDD 2378 TCDF
Variable
2378 TCDD/2378 TCDF
Low High Low High Reference
0.1 49 0.25 2,620 See Table 2-5
concentration in
the dry pulp, dry
basis, ppt (DC)
Weight of the dry pulp
sheets, g (PW)
454
454
454
454
Surface area of the dry
pulp sheets, cm2 (PS)
Rate of transfer from
the pulp to the skin,
h'1 (R)
Percent 2378 TCDD/2378 TCDF 25
available for dermal
absorption, percent (%AD)
Skin surface area, cm2 250
Exposure duration, 2
h/day (ED)
6,000 6,000
Dermal exposure,
mg/day (DED)
0.0005 0.0005
25
300
2
See Table 3-15
6,000 6,000 See Table 3-15
0.0005 0.0005 EPA 1989c
,-13
,-10
25
250
2
-12
25 EPA 1989c
300 See Table 3-15
2 See Table 3-15
4.7x10 ij 2.8x10 1U 1.2x10 ic 1.5x10 ° Calculated
3-36
-------
this exposure assessment. The equation for handling wet pulp was selected
for this operation since the workers have a higher potential for contacting
wet pulp rather than dry pulp. This equation was presented previously in
Equation 12. The 2378 TCDD and 2378 TCDF concentrations for pulp from Table
2-5 are reported on a dry basis. Since the utility workers are handling wet
pulp, this concentration was adjusted to a wet basis by adjusting for the
estimated average pulp composition (11 percent) and assuming that only the
aqueous phase contains 2378 TCDD/2378 TCDF and water. This corresponds to
multiplying the 2378 TCDD/2378 TCDF weight fractions on a dry basis by 0.12
to obtain weight fractions on a wet basis. Table 3-13 summarizes the
variables and results for dermal exposure for the pulp drying operator and
the utility pulp drying operator.
Equations 10 and 11 are used to calculate the TEQ and the percent expo-
sure due to 2378 TCDD. In these two equations, the daily inhalation exposure
from volatilization (Iv) is replaced with the daily dermal exposure (DEW or
DED) from 2378 TCDD and 2378 TCDF. Table 3-14 presents daily and lifetime
average daily TEQ and percent exposure due to 2378 TCDD from dermal exposure
to wet and dry pulp for workers in the pulp-drying operations. Table 3-15
presents the assumptions and uncertainties in the variables used to calculate
dermal exposures for workers in the pulp drying operations.
3.1.3 Papermaking
Papermaking operations include wet-end additives/stock preparations,
coating preparation, paper machine wet-end, paper machine dry-end, and off-
machine coating. There is potential for pulp exposure in the papermaking
stage of pulp and papermaking operations. In this stage, bleached pulp con-
taining PCDDs and PCDFs is processed, and it is assumed that the concentra-
tions of PCDDs and PCDFs remain constant. PCDDs and PCDFs can also be intro-
duced into this stage by the use of recycled white water from the paper
3-37
-------
TABLE 3-13. ESTIMATED DERMAL EXPOSURE TO 2378 TCDD AND 2378 TCDF
FOR PULP DRYING UTILITY OPERATORS
Variable
2378 TCDD/2378 TCDF
concentration, wet
basis, ppt (DC)
Density of the wet
pulp, mg/cm3 (p)
Liquid film thick-
2378
Low
0.012
1,000
0.025
TCDD
High
5.88
1,000
0.025
2378
Low
0.03
1,000
0.025
TCDF
High
314
1,000
0.025
Reference
See Table 3-8
See Table 3-8
See Table 3-8
ness of the wet
pulp, cm (FT)
Liquid equilibrium 13,000
partition coef-
ficient of 2378
TCDD/2378 TCDF from
water, dimension-
less (K)
Absorption coeffi- 0.012
cient of 2378
TCDD/2378 TCDF
through the skin,
h"1 (AD)
Skin surface 250
area, cm2 (S)
Exposure duration, 2
h/day (ED)
13,000
29,000 29,000 EPA 1989c
0.012
0.012
0.012 EPA 1989C
300
250
300
Dermal exposure, 1.4x10
nig/day (DEW)
-16
8.1x10
-14
1.6x10
-16
2.0x10
2
-12
See Table 3-15
See Table 3-15
Calculated
3-38
-------
TABLE 3-14. ESTIMATED TOXICITY EQUIVALENTS AND PERCENT EXPOSURE DUE
TO 2378 TCDD FOR PULP-DRYING OPERATIONS FROM DERMAL EXPOSURE
Daily TEQ, mg/kga
Variable
Pulp-drying operator
Pulp-drying utility
operator
Low
5.9xlO"13
(29)
1.5xlO'16
(47)
High
l.SxlO"9
(2)
2.8xlO"13
(4)
Lifetime
average daily
TEQ, mg/day-kg
Low
3.3xlO"15
(29)
8.6xlO"19
(47)
High
l.ZxlO"11
(2)
1.9xlO"15
(4)
Value in parentheses are percent exposure to 2378 TCDD.
3-39
-------
LU
OH
ZD
I/)
O
Q.
X
LU
_J
SI 00
cc Q;
LU O
Q 1
^^
CD a:
Z. LU
i i CL,
1 0
^£
s: o
I-H ^^
^ K t
oo >-
LU o:
o
z.
t-4 O.
1
00 Z3
LU CL.
\ a:
-. o
Z. Lu
1 H
«=C LU
1 Q
OH 0
LU H-
O
Z CO
^^ r^
CO
a CM
^^
O
(L)
4-
4-
LU
d)
U
C C
CO O
0) - -r-
^ &> 4-*
JD ro CL
co ^ E
C 3
O d) in
in i in
ro JD ro
d) **~
cn to 4-
to o
o
CL
o c
a> o
4J -r-
ro 4->
r- OL
0 E
O 3
tn to
(/) to
«*f| CO
>^
+J
^
C
(O
4»>
t-
O)
0
C
~"i
ai
.c
ai
CD to
c ai
i- -
^_>
O r
r- CM 0)
3 >
O LO O)
o *"*
dJ 4-1
ra *-> co « i
T»3 Q^ ^> O C QJ CO O
0) l_i (-> O.C l-4->4-
in co r u i ro s-
O CO O) 4- O) O
Q-O)-!-! CUifl-O
X (J -> 3 (J co C
cj) ro C I/) I/) --~ co O) O)
4 QJ O ^3 \^ 4_ t f^
OJS--I->CLCOS-OO
r" 3 O X ro CO 3 C *"*
( wi Q.co^:j2 (/>!-«
i i/?
x a. >-H coinscc
O r OLUQJ ? 1 a.EE i- o r a> .^
Q.^^ Q.C Oco fOOIfOSXItOtO
CLO~I ro S- i- to O OJ CL4- "D 4-> C >> OJ.4- 4-> $- S-COJCOTDS-r
O» i- <- CL.- O) ro O 3 ro JD O> O ro
J=«-i TJi ro O i ait-i j=ai-o
-C O3 COCO 3 O i-CDUC CLM l-
Q) cO «C OO E Cn t- Q) Q. CO O CU '" C !->> O r-t jQ 4- JD CDJZ O) E , S- C i_
(/) ^ (^ cxj 4 GC d) "O &- 3O *^ d) QJ l^ CD CO cy
4->r OE Q.4-1 -O t04->4-JC4-OJCLnE
CU3 O O)LUtO3 ( 4-1 CMO
O) OO CO (-> « COE C i ' "O -f-cO
JZ (DO CO rO 2 O -r-LUC T30) tnO
to S- O S.LOL. I- -*: O- ro S_ -r- O
CDCOO o-*->c:4- tn CD to i/i ro
CL «* &- O tf~ "^ E *^ ^^ ^3 rO ^"^»
r^ *S" d) IO d) O d) ^^ fc- T3 J2 r~ C 4-> d) C dJ "O CO
3 LO U 4- J= 10 OJ d> coco O ro S- C CO
CLM- ratn toO-«-> 4- tn~O CLJZ +-> ro JC ro co Cn
4--i- C OtO Od) C4- I
l-i 3in- t->»-d) co XroO-^ins-OdJi i
o d» to -M * > *-> E i- s- a>E odJtocroi oo
-t-> O) Ol C3d)+JC -(-) JD S_ OI4-COGC
O) ro d)O)CO d) -i to CL "- O) (-> C CL OJ E S- E <_)
r~ c f ^^ cjj ^ ,^ (/) co I/) ^ f^ j/) d) *^ d) ^* O 3 d) ^^
c t- ( to <-i ( to co O. co to H-CUUOS-4-'2vi4
o -o
d) (-> CL c
J= i co
>> +-> CL 3 tO
1- 5 r d) CL t/> 1- "O TD
O 4-1/1 d)3 OS-Od)E
O -t-> 4- CL re OJ O (-> i/l ro
O) d) to 4-J=4->cOO
f>cod) C >, i_ -t-> ro S- CLO
4-> M a> f cos- 3S-d)xo >
*->(-in S- T3 oo QJ O) CL QJ O "O
4-d)iO «-> S- CL O 1 Lu CU
Od) CL d)C Cd)Od)O 3
JC dJ i 4- -C - -t- JZ >>JD CO CJ C
4J o 3 o +-> ^»; j^2CD4->r^-t -
J= COQ. W i/» C «- "O CO »->
CDQ.4- d»E co-i-r r CMCO C
i-f i->> +->od) aja) >»<- 31^ o
d)3 3S. cai-J= x:i-s--4->ooro u
3Q.OO-O Oi4--»-> 1 ro TJ 3 5 +J CM *-*
3-40
-------
TJ
CO
3
t
1 *
C
0
u
If)
T-l
I
ro
LU
CO
1-
10
i
3
CO
cu
c
O
in
4 *
O
CU
'[
UJ
CU
o
c c
ro O
CO - -i-
i S- -M
JO ro Q-
fO > E
C 3
O CO in
CO r CO
ro JO ro
CO !-
o: m M-
co o
O
Q.
a c
CO O
4-> -r-
rO -M
i- Q.
U E
0 3
CO CO
co in
c£ ro
>-j
_*->
C
r_
ro
^J
S-
cu
u
c
=3
in i o
ro C 'i-j+J
3 O M-
> O CO !-
CU in !- J=
J- 1- C J= in
3 3 -
CO O CD CU
O -C CO C -C
Q. r*» .r- 4_>
X CO S-
CO i 3 +J
CU i TO 3
CU JO -r- O
J= S O-J=
+-> O > CD
»-> S- 3 3
C|- Q) Q. O
O i-« ^£ S-
LU i- CO J=
C Q. O JC »->
0 5 +->
i- >> CO
-t-> JD CO JZ Ol
ro JC 4-> -i-
3 CU 5 T-
"O E CU >
3 O »-> T-
JZ co -i- ro O
1 ro CO +J ro
Q.
I CO
CU 3 S-
S- Q. O
3 +>
co 1- ro
O O l-
X Q-
CO C O
O
-i- CD
ro 4-> C
E ro -i-
C I- >,
CU 3 S-
Q T3 -O
CU
JC
CU
CD in
C CO
ro E
J- -r-
4-*
0 i
r-~ ^" OJ
3 >
O O QJ
^ -l-> i
CU LO CU
S- S-
3 O 3
CO CO
0 E O
Q. O Q.
X S- X
UJ «t- O
J2 ro J=
ro S-
C 3 CO
^5 ^3
t/> O
U3
3 3 CO ro
CO O JO S- C
O J= O Q.T-
0- «»- 3
X CM r C CO
cu <- a. to co
CO ? i CO !-
CO *""* 3 r^ 4^
JC 1- Q. O -i-
4-> O O >
+J 4-> CO CD'i-
<4- ro J= C 4J ro
O > i i- !-> - O CO
LU CO S- ro S-
C Cu CL.C 3 (0
O O +-> T3 CO
1- >, T- 0 C
-t-> JD co s +-> c o
ro J= «4- ro -i-
S- X) 4-> 4-> !- C -t->
3 CU U J= O) O
T3 E CO ro in 4-> 3
3 O 4J C "O
CU CO C C CU !- O
JZ CO -i- O JC ro fc.
| ro CO O +J E CL
1 1
>> s-
CO i- CU
$- x» CL
3 O
CO S-
O 0 >>
cm- +j
X 'I-
CU C i
O !-
r -r- 4->
ro (-> 3 CO
E (0 S-
C S. CD O
CO 3 C 4->
(""*> "O *r *O
3-41
-------
machine to dilute the pulp slurry prior to its feeding into the wet end of
the papermaking machine. The additional PCDD/PCDF contribution, however,
should be small in comparison to the concentrations of PCDDs and PCDFs in the
bleached pulp. In the papermaking and finishing operations, a potential for
PCDD and PCDF exposure through dermal absorption exists if workers come in
contact with either dioxin/furan-contaminated wet pulp which is to be fed
into beaters or refining equipment or with the paper products.
The workers in dry-end operations are potentially exposed to PCDDs and
PCDFs through dermal contact with paper products, inhalation of vapors during
drying operations, and inhalation of paper dust during normal process opera-
tions. For a particular plant evaluated in a NIOSH study, engineering con-
trols and work practices used to prevent or decrease the amount of dust
inhaled included exhaust systems, the use of dust masks, and cleaning of
equipment every shift to remove accumulated paper dust. A NCASI study to
determine the particulate size distribution of paper dust showed that total
paper dust mass concentration levels ranged from 0.2 to 4.90 mg/m during
3
normal operations, and 31 to 109 mg/m at the time of operation during blow-
down (operations requiring approximately 15 minutes per shift for machinery
cleaning) (NCASI 1988a). Table 3-16 presents the particulate size distribu-
tion results from the NCASI study. In the NIOSH study, both general ventila-
tion and local ventilation (Torit Dust Collection Systems) were provided in
one of the eighteen plants studied; dilution ventilation rates were reported
to be 6 to 10 air changes per hour. The number of air changes was not used
to calculate the ventilation rate.
3-42
-------
TABLE 3-16. PARTICULATE SIZE DISTRIBUTION BY TOTAL DUST CONCENTRATION'
Mass
concentration
range
Low
Medium
High
Slowdown
Average
Minimum
Maximum
Average
Minimum
Maximum
Average
Minimum
Maximum
Average
Minimum
Maximum
<2 ym
0.12
0.07
0.16
0.31
0.00
1.05
0.09
0.00
0.24
0.30
0.00
0.56
Concentration
1 to 10 ym >
0.08
0.00
0.20
0.32
0.11
0.70
0.60
0.19
1.00
4.76
2.12
/ 3
» mg/m
10 ym
0.09
0.05
0.18
0.41
0.16
0.66
3.04
2.30
3.73
62.78
25.56
7.35 101.69
Total
0.28
0.21
0.46
1.04
0.77
1.51
3.73
2.97
4.90
67.84
30.93
109.03
d (NCASI 1988a)
3.1.3.1 Level of Inhalation Exposure--
Three job categories of workers in the paper mill (i.e., wet-end opera-
tor, dry-end operator, and utility operator) are potentially exposed to PCDDs
and PCDFs.
There are two routes for inhalation exposure: 1) vapors from volatil-
ization of PCDDs and PCDFs, and 2) particulates (dust). The utility operator
and dry-end operator may be exposed by both routes of inhalation exposure,
while the wet-end operator is estimated to be exposed only from volatiliza-
tion of PCDDs and PCDFs. It was estimated that wet-end operators, dry-end
operators, and utility operators spend 2, 4, and 6 hours of their shifts,
respectively, in areas of the plant in which there is a potential for inhala-
tion exposure.
VolatilizationThe same calculation procedures previously employed to
estimate inhalation exposure to PCDDs and PCDFs by vaporization (using Equa-
tions 6, 15, and 9) for pulp drying workers was used to estimate inhalation
3-43
-------
exposure to paper mill workers. Table 3-17 summarizes the variables used to
calculate inhalation exposure for the paper mill workers to volatilization of
PCDDs and PCDFs and presents exposure estimates.
The relative toxicity of 2378 TCDF with respect to 2378 TCDD can be
determined by calculating TEQ. In addition, the percent exposure due to 2378
TCDD can also be calculated. Using Equations 10 and 11, these two variables
are calculated. Table 3-18 presents the daily and lifetime average daily TEQ
and percent exposure due to 2378 TCDD for paper mill workers from volatiliza-
tion from wet pulp. Table 3-19 presents the assumptions and uncertainties in
the variables used to calculate the daily exposure and lifetime average daily
exposure for paper mill workers from volatilization from wet pulp.
Particulate matterEquation 17 was used to calculate the inhalation
exposure from PCDD and PCDF contained in particulate matter generated during
paper mill operations. This equation is similar to Equation 9 except that
the Cm in this equation is for the total particulate concentration rather
than the 2378 TCDD/2378 TCDF concentration. In the absence of data on 2378
TCDD/2378 TCDF concentrations in the paper dust, the fraction of 2378 TCDD/
2378 TCDF in the dry pulp was used to allocate the portion of the paper dust
which is 2378 TCDD/2378 TCDF. The dry weight fraction of 2378 TCDD/2378 TCDF
in the pulp, as reported in the 104-Mill Study, was used in the calculation
because the paper dust that is emitted is dry.
Ip = Cm (mg/m3) x 1.25 m3/h x ED (h/day) x W Equation 17
where Ip = daily inhalation of particulate matter, mg/day
Cm = concentration of paper mill dust, mg/m3 (with existing engineering
controls)
3-44
-------
TABLE 3-17. ESTIMATED INHALATION EXPOSURE TO 2378 TCDD and 2378 TCDF
FOR PAPER MILL WORKERS FROM VOLATILIZATION
2378 TCDD
2378 TCDF
Variable
Low
High
Low
High
Reference
Weight fraction of
2378 TCDD/2378
TCDF in the dry
pulp, dry basis
Mole fraction of
2378 TCDD/2378
TCDF in the
pulp, wet basis
(Xa)
Vapor pressure,
atm (P°) (<> 71°C
Molecular weight,
g/g-mole (M)
Temperature, °K (T)
Concentration of
2378 TCDD/2378
TCDF in the
vapor, ppm (Cv)
Ideal gas constant,
atm liter/g-mole
°K
Exposure dura-
tion, h/day (ED)
- Wet-end
operators
- Dry-end
operators
- Utility
operators
Daily inhalation,
mg/day (Iv)
- Wet-end
operators
- Dry-end
operators
- Utility
operators
O.lxlO"12 4.9xlO"U
7.0xlO"16 3.4xlO"13
1.6xlO"9 1.6xlO"9
322 322
298 298
1.5xlO"17 7.2xlO"15
0.0821 0.0821
3.7xlO"17 1.8xlO"14
7.4xlO"17 3.6xlO"14
l.lxlO"16 5.4xlO~14
2.5xlO"13 2.62xlO"9 Table 2-5 104-
Mill Study
data
1.8xlO"15 l.SxlO"11 See Table 3-5
-6
2.0x10
306
298
2.0x10
-6
Schroy 1984,
See Table 3-11
306 EPA 1989b
298 See Table 3-11
4.4xlO"14 4.6xlO"10 Calculated
0.0821 0.0821 Felder 1978
2
4
6
2
4
6
2
4
6
2 See Table 3-19
4 See Table 3-19
6 See Table 3-19
l.lxlO"13 l.lxlO"9 Calculated
2.2xlO"13 2.3xlO"9 Calculated
3.3xlO"13 3.4xlO"9 Calculated
3-45
-------
TABLE 3-18. ESTIMATED TOXICITY EQUIVALENTS AND PERCENT
EXPOSURE DUE TO 2378 TCDD FOR PAPER MILL WORKERS FROM VOLATILIZATION
Lifetime
average daily
Daily TEQ, nig/day TEQ, mg/day-kg
Job category
Wet-end operator
Dry-end operator
Utility operator
Low
l.lxlO"14
(0.03)
2.2xlO"14
(0.03)
-14
3.3x10 1H
(0.03)
High
l.lxlO'10
(0.002)
2.3xlO"10
(0.002)
3.4xlO"10
(0.002)
Low High
6.1xlO"17 7.7xlO"13
(0.03) (0.002)
1.2xlO"16 1.5xlO"12
(0.03) (0.002)
l.BxlO"16 2.3xlO"12
(0.03) (0.002)
Values in parentheses are percent exposure to 2378 TCDD.
3-46
-------
TABLE 3-19. ASSUMPTION AND UNCERTAINTIES IN ESTIMATING INHALATION EXPOSURE TO
2378 TCDD AND 2378 TCDF FOR PAPER MILL WORKERS FROM VOLATILIZATION
Uncertainty
Associated
assumption
Reasonable
possible variance
of assumption
Effects on results
The amount of 2378
TCDD/2378 TCDF in
the paper dust.
Inhalation exposure
duration for wet-end
operator.
The fraction of
2378 TCDD/2378
TCDF in the paper
dust was assumed
to equal the dry
weight fraction
in the pulp.
The duration of Reasonable range Exposure would
in the duration
would be 1 to 4
hours.
range from 0.5
to 2 times the
exposure level.
Inhalation exposure
duration for dry-end
operator.
the exposure was
assumed to be 2
hours, since the
operator spends a
majority of the
shift away from
the paper ma-
chine.
The duration of Reasonable range Exposure would
in the duration
would be 2 to 6
hours.
range from 0.5
to 1.5 times the
exposure level.
the exposure was
assumed to be 4
hours since the
operator spends
half of the shift
away from the
paper machine.
Inhalation exposure The duration of Reasonable range Exposure would
duration for utility
operator.
the exposure was
assumed to be
6 hours, since
the operator
spends a majority
of the shift
near the paper
machine.
in the duration
would be 4 to 8
hours.
range from 0.7 to
1.3 times the
exposure level.
3-47
-------
ED = exposure duration, h/day
W = weight fraction 2378 TCDD/2378 TCDF in the paper dust
Table 3-20 summarizes the variables used to calculate the exposure to
workers from the particulate matter containing PCDDs and PCDFs generated
during paper mill operations.
Equations 10 and 11 are used to calculate the TEQ and the percent ex-
posure due to 2378 TCDD. In these two equations, the daily inhalation expo-
sure from volatilization (TEQv) for 2378 TCDD and 2378 TCDF are replaced with
the daily inhalation exposure from particulate matter (TEQp) for 2378 TCDD
and 2378 TCDF. Table 3-21 presents the daily and lifetime average daily TEQ
and percent exposure due to 2378 TCDD from dry particulate matter for paper
mill workers. Table 3-22 presents the assumptions and uncertainties in the
variables used to calculate the daily exposure for paper mill workers.
The following is an example of the calculation procedure (Equation 17)
used for estimating levels of daily inhalation exposure for dry-end operators
exposed to TCDD from particulate matter:
Lower limit for 2378 TCDD inhalation exposure levels from particulate matter
for dry-end operators
Ip = 0.21 mg/m3 x 1.25 m3/h x 4 h/day x 0.1 x 10"12
= 1.0 x 10"13 mg/day
The following is an example of the calculation procedure for estimating
daily TEQ and percent daily exposure due to 2378 from particulate matter.
Lower limit for dally TEQ and percent daily exposure due to TCDD for dry-end
loader operators from particulate matter
DTEQp = 1.0 x 10"13 + (0.1 x 2.6 x 10"13)
= 1.3 x 10"13
STCDDp = 1.0 x 10"13/(1.0 x 10"13 + 2.6 xlO"13) x 100
= 29%
3-48
-------
TABLE 3-20. ESTIMATED INHALATION EXPOSURE TO 2378 TCDD AND 2378 TCDF
FOR PAPER MILL OPERATORS FROM PARTICULATE MATTER
Variable
Concentration of paper
mill dust, mg/m3 (Cm)
- Dry-end operator
- Utility operator
Amount of 2378 TCDD/-
2378 TCDF in the paper
dust, dry basis (WF)
- Dry-end operator 0
- Utility operator 0
Exposure duration,
h/day (ED)
- Dry-end operator
- Utility operator
Daily inhalation,
mg/day (Ip)
- Dry-end operator 1
- Utility operator 3
2378
Low
0.21
31
.1x10"}?
.1x10""
4
1
.0x10"}?
.9x10""
TCDD
High
4.9
109
4.9x10"}}
4.9x10"*
4
1
1.2x10"?
6.7xlO"y
2378
Low
0.21
31
2.5xlO~J3
4
1
2.6xlO~}2
9.7x10""
TCDF
High
4.9
109
2.62xlO~Q
2.62xlO~y
4
1
6.4x10"?
3.6x10"'
Reference
Table 3-16
Table 3-16
Table 2-5
Table 2-5
Table 3-22
Table 3-22
Calculated
Calculated
The high dust concentration reported for utility operators represent those
achieved during blowdown operations over a short time period and do not
represent a violation of the 8-hour OSHA PEL of 15 mg/m3 for nuisance dust.
3-49
-------
TABLE 3-21. ESTIMATED TOXICITY EQUIVALENTS AND PERCENT
EXPOSURE DUE TO 2378 TCDD FOR PAPER MILL OPERATORS
FROM PARTICULATE MATTER
Lifetime
average daily
Daily TEQ, ing/day TEQ, mg/day-kg
Job category
Low
High
Low
High
Dry-end operator 1.3xlO"13 7.6xlO"9 7.3xlO"16 5.1xlO~n
(29) (2) (29) (2)
Utility operator 4.8xlO"12 4.2xlO"8 2.7xlO"14 2.9xlO"10
(29) (2) (29) (2)
Values in parentheses are percent exposure to 2378 TCDD.
TABLE 3-22. ASSUMPTION AND UNCERTAINTIES IN ESTIMATING INHALATION EXPOSURE TO
2378 TCDD AND 2378 TCDF FOR PAPER MILL WORKERS FROM PARTICULATE MATTER
Uncertainty
Associated
assumption
Reasonable
possible variance
of assumption Effects
on results
Inhalation exposure
duration for dry-end
operator.
Inhalation exposure
duration for utility
operator.
The duration of Reasonable range Exposure would
the exposure was
assumed to be
4 hours, since
the operator
spends half of
the shift in
operations which
generates dust.
The duration of
the exposure was
assumed to be
1 hour. The op-
erator would be
exposed to paper
dust during
blowdown and for
a period of time
after blowdown
for the dust to
settle.
in the duration
would be 2 to 8
hours.
Reasonable range
in the duration
would be 0.5 to
1.5 hours.
range from 0.5
to 2 times the
exposure level.
Exposure would
range from 0.5 to
1.5 times the
exposure level.
3-50
-------
3.1.3.2 Level of Dermal Exposure--
Dermal exposure levels to 2378 TCDD and 2378 TCDF were computed based on
the worst-case assumption that workers do not wear any type of gloves that
effectively limit exposure to PCDDs and PCDFs. The same calculation pro-
cedures previously employed to estimate dermal exposure levels for the pulp
mill operators and pulp-drying workers were used to estimate the dermal
exposure levels for the paper mill operators.
The wet-end operator responsibilities include pulping, bleaching, beat-
ing, refining, application of additives, and blending proportioning. Dermal
exposure duration was based on engineering judgment. The equation for han-
dling wet material was selected for this operation, since the worker will be
handling the wet end of the process line. This equation was presented in
Equation 13. Table 3-23 summarizes the variables and results for dermal
exposure for the paper mill wet-end operators.
The dry-end operator responsibilities include supercalendering, rewind-
ing, slitting, cutting and sheeting, trimming, packaging, and shipping. Some
shipping and packaging operations may be performed in a separate part of the
same plant. Dermal exposure duration was based on engineering judgment. The
equation for handling dry material was selected for this operation, since the
worker handles dry paper. This equation was presented in Equation 17.
The utility operator responsibilities include machine cleaning (blow-
down), and assisting dry-end and wet-end operators. Dermal exposure duration
was based on engineering judgment. The equation for handling dry material
was selected for this operation, since the worker has a higher potential for
contacting dry paper than wet paper. This equation was presented in Equa-
tion 13. Table 3-24 presents the estimated dermal exposure to 2378 TCDD and
2378 TCDF for dry-end and utility operators.
3-51
-------
TABLE 3-23. ESTIMATED DERMAL EXPOSURE TO 2378 TCDD AND 2378 TCDF
FOR WET-END OPERATORS IN PAPER MILLS
Variable
2378 TCDD/2378 TCDF
concentration, wet
basis, ppt (DC)
Density of the wet
pulp, mg/cm3 (p)
Liquid film thick-
ness of the
pulp, cm (FT)
Liquid equilibrium
partition coeffi-
cient of 2378 TCDD/-
2378 TCDF from
water deminsionless
(K)
Absorption coeffi-
cient of 2378 TCDD/-
2378 TCDF through
the skin h"1 (AD)
Skin surface
area, cm2 (S)
Exposure duration,
h/day (ED)
Dermal exposure, 1
mg/day (DEW)
2378 TCDD
Low High
0.012 5.88
1,000 1,000
0.025 0.025
13,000 13,000
0.012 0.012
250 300
2 2
.4xlO"16 S.lxlO"14
2378 TCDF
Low High
0.03 314
1,000 1,000
0.025 0.025
29,000 29,000
0.012 0.012
250 300
2 2
1.6xlO"16 2.0xlO"12
Reference
See Table 3-8
See Table 3-8
See Table 3-8
EPA 1989c
EPA 1989C
See Table 3-23
See Table 3-23
Calculated
3-52
-------
TABLE 3-24. ESTIMATED DERMAL EXPOSURE TO 2378 TCDD AND 2378 TCDF
FOR PAPER MILL DRY-END OPERATORS AND UTILITY OPERATORS
2378 TCDD
2378 TCDF
Variable
Low
High
Low
High Reference
2378.TCDD/2378 TCDF 0.1
concentration in the
dry paper, dry
basis, ppt (DC)
Weight of the dry 4.5
paper, g (PW)
Surface area of the 600
dry paper, cm2 (PS)
Rate of transfer 0.0005
from the paper to
the skin, h l (R)
Percent 2378 TCDD/ 25
2378 TCDF available
for dermal absorp-
tion, percent (%AD)
Skin surface area,
cm2 (S)
- Dry-end operator 250
- Utility operator 250
Exposure duration,
h/day (ED)
- Dry-end operator 4
- Utility operator 6
Dermal, exposure
nig/day (DED)
- Dry-end operator 9.4x10
- Utility operator 1.4x10
-14
-13
49
4.5
600
0.0005
25
300
300
4
6
5.5x10
8.3x10
-11
-11
0.25
4.5
600
0.0005
25
250
250
4
6
2,620 Table 2-5
4.5 NCASI 1988c
600 NCASI 1988c
0.0005 EPA 1989c
25 EPA 1989c
300 Table 3-26
300 Table 3-26
4
6
Table 3-26
Table 3-26
2.3xlO~j, 2.9xlO~Q Calculated
3.5xlO"1J 4.4xlO"y Calculated
3-53
-------
Equations 10 and 11 are used to calculate TEQ and percent exposure to
2378 TCDD. Table 3-25 presents daily and lifetime average daily TEQ and
percent exposure due to 2378 TCDD for dermal exposure for workers in the
papermill operations. Table 3-26 presents the assumptions and uncertainties
in the variables used to calculate dermal exposures for paper mill workers.
This includes the variables used to calculate dermal exposure from handling
wet paper from Table 3-23 and handling dry paper from Table 3-24.
3.1.4 Paper Converting
There is potential for PCDD and PCDF exposure in converting operations.
The potential for dermal exposure arises from manual handling of dry bleached
paper-based stock and finished product which contain PCDDs and PCDFs, whereas
the potential for inhalation exposure arises from dry paper dusts created
during the various converting operations. In the finishing stages, dermal
contact may occur through arm and other skin surfaces during the following
building operations: 1) building of the reel; 2) changing of the roll; and
3) trimming, cutting, transporting, wrapping, or packaging of the paper. For
certain activities during converting operations (e.g., quality assurance),
workers may also have skin contact with the final paper product.
Table 3-27 presents data from a NIOSH study of worker exposures to paper
dust from the dry end of paper machines producing tissue paper, paper towels,
and newsprint. The following is an estimation of inhalation exposure to 2378
TCDD and 2378 TCDF for pulp mill workers.
3.1.4.1 Level of Inhalation Exposure
The various job categories in the converting operation include machine
operators; 3rd, 4th, and 5th hands; back tenders; slitters; and cutters. In
3-54
-------
TABLE 3-25. ESTIMATED TOXICITY EQUIVALENTS AND PERCENT EXPOSURE
DUE TO 2378 TCDD FOR PAPER MILL OPERATORS FROM DERMAL EXPOSURE
Job category
Wet-end operator
Dry-end operator
Utility operator
Daily TEQ
Low
l.SxHT16
(47)
1.2xlO"13
(29)
l.SxlO"13
(29)
a
, mg/day
High
2.8xlO"13
(4)
3.5xlO"10
(2)
5.2xlO-10
(2)
Lifetime
average daily
TEQ, mg/day-kg
Low
8.6xlO"19
(47)
6.6xlO"16
(29)
9.8xlO"16
(29)
High
1.9xlO"15
(4)
2.4xlO"12
(2)
3.5xlO"12
(2)
a Values in parentheses are percent exposure to 2378 TCDD.
3-55
-------
o
H-
LU
ce
~^
oo
0
o.
X
LU
_,
^£
z:
a: to
LU C£
O LU
^x
cr a;
z c.-
P "*
«t _j
s: _i
1 1 I 1
r- S
00
LU ce
LU
z o-
HH ^t
O.
00
LU O£
0
1 | |
P fc^»
Z
l i U_
«£ 0
r <_>
cr 1-
LU
<_> cc
^*^ I*"***
^5 OO
C\j
o
z o
«c z
^c
00
z o
o o
i i O
H- r-
0-
2: oo
"""^ rx.
00 CO
OO CM
«£
VO
CM
|
ro
LU
_J
CO
^^
1
CO
4->
^~
3
CO
QJ
J-
C
o
CO
4*J
O
QJ
t^_
t^_
LU
CJ
u
c c
(O O
QJ *- !
* 1- 4->
.O CO O.
co ^ E
C 3
O CJ CO
CO i CO
CO .O CO
QJ »r-
or to M-
to o
o
D.
o c
QJ O
4-^ 'f°*
tO 4->
r- Q.
U E
0 3
to to
to co
e£ CO
>^
+J
C
^
CO
4-}
I_
QJ
U
C
^^
OJ
Cn co
f* QJ F~~
cc E cu
$-->
C 4-> o;
"O4-Ji -DI -OLnaji
i 0,'CU i CM i --CO-'
31T>.C> 3O) 3O4->>
O4->QJ COS- CCtl
§r* 2 4-^ 3 ^ E CO r-~
co co O CJ
QJ i- CJ QJ UO O QJ i- E CJ
J-4-ES- i_.Q- i. i*_ .!= j_
3-t-3 30X 34^3
COCJ4-'tO tOCJ tOQJcO
O 9v O OE CC71CMO
O.CCMQ. Q.OQJ Q. C O.
xco«x x s- x: xroox
LU S- in OJ LU 4- 4-' LU S- -M QJ
QJ x: ^r
O 4-* O CJ CJ
CO >> 0*"^ O -CO -CO
*4~ ^^ o ^** CO CO 4-3 4-^ 4-^ 4-^
l-i O CJ »
3cOOCoS-r-iCM C ii CCM
CO >- 4-> .C co 00 -r- -r-
4-J o cr> CJ a-
- CD t- C O C7> CD
COOtO<4-COl- COi COi
Q-O4->J-COO S-3 J-3
-OCLC3CJT3 O O
QJ "O XOcoL-C CJj^ CJ3
coi cji-oa/ i i
O 3 H . g~ f cS c^ c /^ c
O. O CJ ^^ !-!- o co O CO O to
XOX3-^O- C-i-' C-r-S-
O 3 CO CO T3 O 4-> to O 4-> 3
COi T3r COCOi- COCOO
aJOJUCCJ3cg COS-3 CCS-.C
JT&-CCO.COE CJ3O a' 3
1 cO-r-.Cr 2U Oi-D^: QC'OCO
j_
' O
QJ LU 5 QJ CO C QJ 1 QJ4->4->
UO. -COUCJ -r- i. 1 -O rc >> 1 ^2 ro 4-
co X>4->r-Ci-COJ!K:i-O X S-4-»E X S-T-
»4_>,c:o aico-coof- cjoo-r-c cuocjx:
S-JDco^Jt3S- C M- 4JQ.S-S- 4->Q.co-
3 C CJ CJ CJ T3 c«a ^^ CJ O O t) CJ O co
CO ^D E ^" 'C ^4 U E CJ w E U f~ ^3 fr} t~ "^3 QJ CJ
CU f~~ C^ ^^~ CO {"^ CO E t^ 00 4^ QJ CJ CO ^^ * 4*^ CJ CJ >^^ ^
^ 4^ co ^c *^ t^_ jc c^ LJ? CO E ^^ E '^ *O E ^ 4^ co
r- CO CX CO 9>"G 1- CL OCTi l4_34-> XO) M-34->
-^E C!-'- 3-OXOO«-i OtO CJCOS. OtO <+_to
co'i-s-o-ccJcocotnco toaj.c co tocJOto
4->OCO -C CO CM i i CCOU4-J4J CCOU O
OtO 4- QJ 4J QJ QJ -OOO O C: t|_w o CH-c_)
QJ QJ 6-S S- -C jCflXrtOCef i-to-i-co-r- CO -i-CO-i-c O
CO O 3 r 4-> 4-' - I -i-cOO 4JCOCO-O-CCJ 4->COCOcol-
OcoOtO C C Z U>^3 i- ^ CO ^3 4 CO CU 3O 4-* 3 O £1 4-*
QJ QJ CCQ.4-) C=t-E> CJCO.C!~ QJ QJ CO -C QJ
g ^ Q »r CO CJ QJ tf CO 3 O CO f o O ^* ^ P*~ o *"> c~
1 co4->4_x:s-X)O.ctoti_E 1 Q.CM 4-> O 4-> t CL^J- co -i-
CO
J- c i- c s-
1 O U- O O O O
>>4-> O -i- 4J -i- 4J
ca&-cao 4-> ro 4->co
OJ'OS-r coi- cOS-
S- QJ O J- QJ S- QJ
CO«CX4->CO 3O. 3d.
o o r>- -co -a o
OJ C "C CO
O CJ ^> QJ CM CJ "O CJ ^3
CO 1 4-> tO i. C i- C
t- QJ r Q. C CO 1 CO 1
3 3 *^ X CO O 4~* O ^j ^"^
to 4-1 QJ d. QJ CL S- -D
QJ 3 Q X 5 X -O QJ
C -C QJ O QJ QJ 3
r-4J-0_aO CJ CJ C
\s p» i ,- ^ ^^ * ,__
Jt b. l~~ r^ &_ r~ ^_ Br~
t/1 OJ CD "O fO+-> rC4-> 4->
J- 00 E E C
QJ ^U ^D ^3 f^^ ^ t« ^ L- ^S
.c .c c o ro cio QJ o u
» X O 5 CM Qtn Qtl- «^
3-56
-------
o
o>
3
c
c
o
u
<£>
CVJ
1
n
LU
- I
CD
i^
1
CO
4_>
1
3
CO
JD re o.
re > E
C 3
o a; co
CO 1 CO
re jo re
^E^CL)
i C *->
3 OJ O)
c tv «* s-
22 '3
-t-> i 1 CO
0; QJ o
c r^ *^ Q_
3 C X
CO QJ re QJ
0 CT,
Q. C 1^- Q)
x re -C
UJ i- O 4J
QJ
J= O
»-> *->
r
QJ
QJ JO
o-.
c -o
re r
o
QJ 2
r«-
_(*^ ^
re o co
C -r- S-
O -t-> 3
co re o
03 S- Jn
QJ 3
Qi T3 CO
O) 1 **- CO
i jo re c co
X S- QJ
Q) 0 QJ >, 0
+J Q--t-> 0
Q; O -r- $-
JC -D 1- Q.
4-> QJ QJ O
E *~ "*~^ QJ
4- 3 -> re JZ
O CO E 4J
CO QJ
c re u re c
O C -i-
r- CO ! CO
-t-> re CO T3 -4->
re S c H-
s_ co a> -
3 QJ S- O.JZ
"D i- 3 CO CO
3 o re
QJ co J= i- QJ QJ
-c o o -c s.
H- O.VD +->»-> re
^^
M
r-
O) -!->
J- 3
3
CO S_
O C
Q.U-
X
QJ C S-
O O
. __ ,^_ » ^
re -p re
E re s-
t s-
-------
TABLE 3-27. PERSONAL MONITORING RESULTS FOR
EXPOSURE TO DUSTS IN PAPER CONVERTING OPERATIONS'
Line
Paper Machine 1
( 180-i n. tissue
machine)
Paper Machine 2
( 180-i n. tissue-
towel machine)
Paper Machine 3
(258-in. news-
print machine)
Sample
No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
Job
classifi-
cation
Third hand
Fourth hand
Fifth hand
Third hand
Fourth hand
Fifth hand
Third hand
Fourth hand
Fifth hand
Core cutter
Back tender
Roll wrapper
Total dust
sampling
time
(24-h)
0837-1533
1100-1124
0857-1533
1100-1124
1622-2256
1533-2228
1616-2256
1555-2238
0835-1533
1618-2140
1605-2239
0834-1533
1603-2241
0834-1533
1630-2312
1630-2300
1628-2300
1631-2255
1627-2258
1628-2256
Dura-
tion,
min.
416
24
396
24
394
415
400
403
418
322
394
419
398
419
402
390
392
384
391
388
Concen-
tration,
mg/m3
9.1
10.0
4.4
8.1
1.5
1.3
0.9
0.7
6.0
1.9
3.3
1.5
9.1
0.6
0.3
1.0
0.3
0.3
0.3
0.4
Concen-
tration
8-h TWA,C
mg/m3
7.89
0.50
3.6
0.4
1.2
1.1
0.8
0.6
5.2
1.3
2.7
1.3
7.5
0.52
0.20
0.81
0.25
0.20
0.20
0.3
3 (NIOSH 1983)
Collected on pretared 5-um PVC filters and determined by gravitational
analysis.
c The concentration data were recalculated for an 8-hour time-weighted
average (TWA) for exposure modeling purposes.
3-58
-------
the paper converting industry, dust generated during cutting and trimming
operations is the only potential route for inhalation exposure. All opera-
tors in the production area were assumed to be exposed to the paper dust for
the entire 8 hours of their shift.
The same calculation procedure previously employed to estimate inhala-
tion exposure from dust for the paper mill operators was used to estimate the
inhalation exposure levels from dust for the paper converting workers. Val-
ues for the dust concentration were calculated for an 8-hour exposure period
from concentrations given in Table 3-27. Table 3-28 summarizes the variables
and results used to calculate the exposure for the paper converting operator
to dust containing 2378 TCDD and 2378 TCDF at the facility. The concentra-
tions of 2378 TCDD and 2378 TCDF were obtained from Table 2-5. The concen-
trations were estimated to be the same in pulp as in paper assuming that
PCDDs and PCDFs remain in the pulp through the papermaking and converting
operations.
TABLE 3-28. ESTIMATED INHALATION EXPOSURE TO 2378 TCDD AND 2378 TCDF
FOR PAPER CONVERTING WORKERS FROM PARTICULATE MATTER
2378 TCDD
2378 TCDF
Variable
Low
High
Low
High
Reference
Concentration of
paper, mill dust,
mg/m3 (Cm)
Amount of dioxin in
the mixture, (W)
Exposure duration,
h/day (ED)
Daily inhalation,
mg/day (Id)
0.2
7.9
0.2
7.9 Table 3-27
O.lxlO"12 4.9X10"11 2.5xlO"13 2.62xlO"9 Table 2-5
2.0xlO"13 3.9x10
8 88 Table 3-30
"9 5.0xlO"13 2.1xlO"7 Calculated
3-59
-------
Equations 10 and 11 are used to calculate the TEQ and the percent expo-
sure due to 2378 TCDD. Table 3-29 presents the daily and lifetime average
daily TEQ and percent exposure due to 2378 TCDD for the paper converting
operators from particulate matter. Table 3-30 presents the assumptions and
uncertainties in the variables used to calculate the daily exposure and
lifetime average daily exposure for the paper converting operators from
particulate matter.
3.1.4.2 Level of Dermal Exposure
Dermal exposure to 2378 TCDD and 2378 TCDF was based on the assumption
that workers do not wear gloves that effectively limit exposure. The same
calculation procedure as that used for the paper mill operators' dermal
exposure was used to estimate the dermal exposure levels for the paper
converting operator. Dermal exposure was based on engineering judgment. The
equation for handling paper was selected for this operation since the worker
will be handling dry paper rather than wet pulp. This equation was presented
in Equation 17. Table 3-31 summarizes the variables and results for dermal
exposure for the paper converting operators.
Equations 10 and 11 are used to calculate TEQ and the percent exposure
due to 2378 TCDD. Table 3-32 presents the daily and lifetime average daily
TEQ and percent exposure due to 2378 TCDD from dermal exposure for paper
converting workers.
Table 3-33 presents the assumptions and uncertainties in the variables
used to calculate the dermal exposures for paper converting workers in Table
3-31.
3-60
-------
TABLE 3-29. ESTIMATED TOXICITY EQUIVALENTS AND PERCENT EXPOSURE DUE TO
2378 TCDD FOR PAPER CONVERTING OPERATORS FROM PARTICULATE MATTER
Daily TEQ, ing/day
Lifetime
average daily
TEQ, mg/day-kg
Variable
Low
High
Low
High
Toxicity equivalents
2.5xlO"13 2.5xlO"8 1.4xlO"15 1.7xlO"10
(29) (2) (29) (2)
Values in parentheses are percent exposure to 2378 TCDD.
TABLE 3-30. ASSUMPTIONS AND UNCERTAINTIES IN ESTIMATING
INHALATION EXPOSURE TO 2378 TCDD AND 2378 TCDF
FOR PAPER CONVERTING WORKERS FROM PARTICULATE MATTER
Uncertainty
Associated
assumption
Reasonable
possible variance
of assumption
Effects on results
Inhalation exposure
duration for paper
converting operator.
The duration of
the exposure was
assumed to be
8 hours since
the operator is
in the process
area the entire
shift.
3-61
-------
TABLE 3-31. ESTIMATED DERMAL EXPOSURE TO 2378 TCDD AND 2378 TCDF
FOR PAPER CONVERTING WORKERS
Variable
TCDD/TCDF concentra-
tion, ppt (DC)
Weight of the dry
paper, g (PW)
Surface area of the
dry paper, cm2 (PS)
Rate of transfer
from the paper to
the skin, h l (R)
Percent 2378 TCDD/
2378 TCDF available
for dermal absorp-
tion percent (% AD)
Skin surface area,
cm2 (S)
Exposure duration,
h/day (ED)
Daily dermal, mg/day
(DED)
2378
Low
0.1
4.5
600
0.0005
25
250
8
1.9xlO"13
TCDD
High
49
4.5
600
0.0005
25
300
8
l.lxlO"10
2378
Low
0.25
4.5
600
0.0005
25
250
8
4.7xlO"13
TCDF
High
2,620
4.5
600
0.0005
25
300
8
5.9xlO"9
Reference
Table 2-5
NCASI 1988c
NCASI 1988c
EPA 1989c
EPA 1989c
Table 3-30
Table 3-30
Calculated
3-62
-------
TABLE 3-32. ESTIMATED TCDD EQUIVALENTS AND PERCENT EXPOSURE DUE TO
2378 TCDD FOR PAPER CONVERTING OPERATORS FROM DERMAL EXPOSURE
Lifetime
/erage dai
exposure.
mg/day mg/day-kg
average daily
Daily exposure, exposure,
Variable Low High Low High
Toxicity equivalents 2.3xlO"13 7.0xlO"10 1.3xlO"15 4.7xlO"12
(29) (2) (29) (2)
Values in parentheses are percent exposure to TCDD.
3-63
-------
o
t
LU
ce
ra
OO
o
D-
X
LU
_J OO
^t *"***
s: LU
ce ^
1 1 1 fy
D O
0
Z CE
i Z
1 1-1
<: i
s: ce
I i LU
1 >
oo z
LU O
O
z
H«H fV*
LU
00 D-
LLJ c£
P
Z ^
i-i O
«=C u_
1-
fy 1 1
LU O
0 O
Z h-
Z3
00
o r*^
z co
f. oj
00 Q
Z Z
o <:
i i
1 0
Q- O
s: o
13 t
t/o
00 00
«C f-
CO
OJ
co
CO
i
CO
LU
i
CO
^^
1
00
+J
3
OO
QJ
S-
C
O
00
«4_)
O
OJ
«*-
LU
QJ
O
C C
ro O
QJ !- !-
i S- +->
-O rO O-
*o > E
C 3
O QJ 00
OO 1 OO
re J2 ro
QJ !
o: oo <4-
00 O
o
CL
o c
QJ O
4^ °r~
ro 4->
i- Q.
U E
O 3
to 10
OO OO
^^
+J
C
tfm
(O
4^
^
QJ
U
C
^
o
XJ -M r-
f QJ OJ
3 LO JC >
O -M QJ
S E i
O OO
QJ S- QJ QJ
S- >*- E S-
3 T- 3
(/) OJ 4~^ t/1
o o> o
a. c oj n.
X ro -X
LU S- LO QJ
QJ J=
(J 4J O
rO X O C
<4-l JQ ^: IT3 CO
S r CJ QJ ***
3 ro O rO i- t-n OJ
00 !-(-> JO (O CO
t-: O 0.
C. C t-l
- Q- S- C 0
Jxi +J 3 rO ro Q; >4-
00 O 00 <+- 00 S-
0. O (-> S- ro O
O Q. C 3 QJ -O
QJ T3 X O 00 S- C
OO i QJ S- O QJ
O 3 4- C C O-
D- O QJ " ^ *r- 'r- O
X O XJ ^< Q.
Q) 3 IO 00 XJ -
ro r X»
QJ QJ U C QJ 3 M
J= S- C rO J= O E
H- ro -r- J= I 2 U
i i ro
QJ LU 5 QJ *T3 C QJ 1 QJ
OO- JTOOOJ <- S- IJDrO S-
rO XJ4->f CS-OOJiJS-O X S- ro
«4->>CO QJro- OOOM- QJOQJQJ
S-JDroj^X;S- C 4- - 4->C.S-oo
3 C QJ QJ QJ XJ w *-^ QJ O M- 00
oo XJ E *^~ ro 4 o E QJ ^ E O «C X? ^-^ QJ
QJ i O M-fOOtoEOOO -MQJQJCO
C 4-* CO g~ »r- If ^ O O OO E J^ QJ O
f ro O. oo CD x) S- O- O Cft M 3 -I-* S
^E QJ-r- 3X)XOOt-H OOO QJQ.
OO *r H (J ^* QJ OO C QJ LO CO OO QJ *~
4JOrO J= ro OJ i i C(OO-»->QJ
X> OO *t QJ 4-> QJ QJ XJ OO O C t~
QJ QJ fe^ Sv ^ p j/j r* (/) c ^C "^ OO *^ OO ^-*
00 C 3 1 >->«->- 1 !- ro O -t-»rotOX>
OOOOlO C C Z ro2 CC
O.rOi-1 QJ C QJ QJOO S- OOQJ-i-
X jt S- 00 QJ E «J QJ 30JS-Q.
QJ QJ OJ OO OJ OJ OOrOr^OO X>S-3V)^->
fOjQO)*OL.2 QJOOJ=S--r-
g~ S O *^ ro QJ QJ *^- ro 3 QJ ro *~ o O g~
H_(04J<4-J=S-J3OJ=00»4-E r O.CO -t-> OO
1 XJ C
»-> C O
S. ro !-
rO QJ QJ 4-^
QJ > JD Q ro CD
s- c o s- c
ro O XJ O 3-i-
0 f- XJ «->
OJ 3 S-
0 S- O 00 QJ QJ
rO QJ 2 r^ S- >
«4- Q. CO 3 C
S. ro S- OJ 00 O
3 a, o o u
to 4-> o D-
QJ fO +-> U- X S- 00
C J= S- O QJ Q> S-
i- *-> QJ XJ t-5 O. O
^i Q. QJ r i fO +->
oo QJ O oo rOO.(O
S- O CO E S-
QJ QJ cn o.r^ s_ s_ QJ
J=J=CXCO QJOQ.
( S -i- QJ OJ O«4-O
3-64
-------
3.1.5 Nonwoven Industry
Workers in the nonwoven industry are potentially exposed to PCDDs and
PCDFs through the handling of the pulp. Inhalation of dust may be possible
during the machining of pulp; however, area dust samples for nonwoven opera-
tions are not available to identify any potential for dust inhalation.
Inhalation exposure to all workers in a nonwovens manufacturing facility
may occur because of the mechanical processing of the dry pulp, which may
create pulp dust in the workplace. Plants which produce personal and medical
hygiene products such as diapers and surgical masks are required to follow
Food and Drug Administration regulations on the amount of allowable area dust
(Cunningham 1990). Typically, pulp dust resulting from the hammer mill is
reclaimed through a vacuum screen formed by a vacuum filter. The filter has
a 99+% efficiency and can filter particles as low as 1 to H microns. These
filters recycle the pulp dust to the hammer mill (Lammers 1989). Dermal
exposure may occur to the operator feeding the pulp sheet manually into the
hammer mill, but in automated nonwoven facilities the pulp is machine-fed
into the hammer mill, and therefore there is no skin contact with the pulp.
No information was available on the number of manual versus automated plants
(Cunningham 1990).
3.1.5.1 Level of Inhalation Exposure
Inhalation exposure to PCDDs and PCDFs was based on the assumption that
workers do not wear respiratory protection. The same calculation method as
that used for paper converting operators was used to estimate the exposure
levels for nonwoven workers. Exposure duration was assumed to be the entire
3-65
-------
8-hour shift since no data were available. Table 3-34 summarizes the var-
iables and results for inhalation exposure from pulp dust for the nonwoven
workers. All workers in the nonwovens category were assumed to have similar
exposures regardless of the type of product manufactured.
TABLE 3-34. ESTIMATED INHALATION EXPOSURE TO 2378 TCDD AND 2378 TCDF
FOR NONWOVEN WORKERS FROM PULP DUST
Variable
Concentration of
2378 TCDD
Low High
0.2 0.5
2378 TCDF
Low High
0.2 0.5
Reference
NIOSH 1985
l.OxlO"13 4.9xlO~U 2.5xlO"13 2.62xlO"9
8
Table 2-5
Table 3-36
Calculated
pulp dust,
mg/m3 (Cm)a
Amount of TCDD/
TCDF in the
mixture, (WF)
Exposure duration,
h/day (ED)
Daily inhalation, 2.0xlO"13 2.4xlO"10 5.0xlO"13 1.3xlO"8
mg/day (Ip)
a These concentrations are below the OSHA nuisance dust standard of 15 mg/m3.
Equations 10 and 11 are used to calculate the TEQ and the percent expo-
sure due to TCDD. Table 3-35 presents the TEQ and percent exposure due to
2,3,7,8 TCDD from particulate matter for the daily exposure and lifetime
average daily exposure for the nonwoven workers. Table 3-36 presents the
assumptions and uncertainties in the variables used to calculate the inhala-
tion exposure from particulate matter for the nonwoven workers.
3.1.5.2 Level of Dermal Exposure--
Dermal exposure levels to PCDDs and PCDFs were based on the assumption
that workers do not wear any types of gloves that effectively limit exposure
to PCDDs and PCDFs. The same calculation method as that used for pulp mill
operators' dermal exposure was used to estimate the exposure levels for the
3-66
-------
TABLE 3-35. ESTIMATED TOXICITY EQUIVALENTS AND PERCENT EXPOSURE DUE TO
2378 TCDD FOR NONWOVEN WORKERS FROM PARTICULATE MATTER
Daily exposure,'
nig/day
Lifetime
average daily
exposure,
mg/day-kg
Variable
Low
High
Low
High
Toxicity equivalents 2.5xlO"13 1.6xlO"9 1.4xlO"15 l.OxlO"11
(29)
(2)
(29)
(2)
Values in parentheses are percent exposure to 2378 TCDD.
TABLE 3-36. ASSUMPTIONS AND UNCERTAINTIES IN ESTIMATING INHALATION EXPOSURE
TO 2378 TCDD AND 2378 TCDF FOR NONWOVEN WORKERS FROM PARTICULATE MATTER
Reasonable
Associated possible variance
assumption of assumption Effects on results
Uncertainty
Inhalation exposure The duration of
duration for nonwoven the exposure was
operator. assumed to be
8 hours since
the operator is
in the process
area the entire
shift.
3-67
-------
nonwoven workers. Since worker activity data were not available, it was
assumed that the nonwoven worker would come into contact with the pulp 6
hours per day. Dermal exposure duration was based on engineering judgment,
since no data were available. Table 3-37 summarizes the variables and
results for dermal exposure for the nonwoven workers.
Equations 10 and 11 are used to calculate the TEQ and the percent expo-
sure due to 2378 TCDD. Table 3-38 presents the daily and lifetime average
daily TEQ and percent exposure due to 2378 TCDD from dermal exposure for
nonwoven workers. Table 3-39 presents the assumptions and uncertainties in
the variables used to calculate the dermal exposures for the nonwoven workers
in Table 3-37.
3.1.6 Commercial Users
During the commercial use of paper products, workers may be exposed to
PCDDs and PCDFs through dermal contact with bleached paper products. The
skin surface area contacting the bleached paper product and the amount of
contact time varies with each job category. Almost all workers contact paper
at some point in the work day. A wide variety of worker categories includ-
ing secretaries, librarians, teachers, and accountants use various types of
paper products for a large portion of the work day. Since many of the varia-
bles for the calculation of dermal exposure are not known, some assumptions
were made. The number of workers in certain job categories was obtained from
the United States Census Bureau and was the most complete and recent data.
The concentration of 2378 TCDD and 2378 TCDF was estimated to be that of the
pulp concentration because the PCDD and PCDF levels in paper products mea-
sured in the NCASI study was not representative of the entire paper industry.
For medical workers, the concentration of 2378 TCDD and 2378 TCDF was assumed
3-68
-------
TABLE 3-37. ESTIMATED DERMAL EXPOSURE TO 2378 TCDD AND 2378 TCDF
FOR NONWOVEN WORKERS
Variable
TCDD/TCDF concen-
tration, ppt (DC)
Density of the
pulp, mg/cm3 (p)
Liquid film thick-
ness of the
pulp, cm (FT)
Liquid equilibrium
partition coef-
ficient of TCDD/
TCDF from water,
dimensionless (K)
Absorption coeffi-
cient of TCDD/TCDF
through the skin,
h"1 (AD)
Skin surface
area, cm2 (S)
Exposure duration,
h/day (ED)
Dermal exposure, 4
mg/day (DEW)
2378 TCDD
Low Hi
0.012
1,000 1
0.025 0
13,000 13
0.012 0
250
6
9h
5.88
,000
.025
,000
.012
300
6
.2xlO"16 2.4xlO"13 1.
TABLE 3-38. ESTIMATED TOXICITY
2378 TCDD
FOR NONWOVEN
2378
Low
0.03
1,000
0.025
29,000
0.012
250
6
OxlO"15
EQUIVALENTS AND
OPERATORS
TCDF
High Reference
314 See Table 3-8
1,000 See Table 3-8
0.025 See Table 3-8
29,000 EPA 1989c
0.012 EPA 1989c
300 See Table 3-39
6 See Table 3-39
l.SxlO"11 Calculated
PERCENT EXPOSURE DUE TO
FROM DERMAL EXPOSURE
Daily exposure,'
nig/day
Lifetime
average daily
exposure,
mg/day-kg
Variable
Toxicity equivalents
Low
5.2xlO"16
(29)
High
1.6xlO"12
(2)
Low
2.9xlO"18
(29)
High
l.OxlO"14
(2)
Values in parentheses are percent exposure to 2378 TCDD.
3-69
-------
o
1
UJ
C£
^"*
(/}
O
D-
X
LU
_J
«5J
2.
rx
UJ oo
o a:
UJ
CD ^
Z Qi
1-1 O
1 3
s: z:
» t UJ
1 IS-
C/0 O
LU 3
z
Z O
" Z
e/o a:
LU O
l i U.
t
z: u.
t i Q
^C C-3
t 1
a:
LU 00
o r^.
Z 00
=> CM
a o
z z
^c ^t
CO Q
Z O
O CJ
I
t
O- 00
§r>.
CO
^
3
to
QJ
S-
c
o
to
4->
o
QJ
(f_
LU
QJ
0
C C
re o
CD 'I *r-
i~ V 4 >
o re Q-
re > E
C 3
O QJ c/)
V) i tO
re -Q re
O) M-
O£ l/> 4-
ui o
o
Q.
T3 C
Q) O
4-* "r~
re -4->
i- a.
o E
0 3
to to
to to
O E QJ
0 4-> -C -i-
i Q) OJ » C (-»
3 Lf) J= > 3 OJ QJ
O 4-> 0) O QJ «d" i.
^ E 5 S 3
O to 4-> i 1 t/)
QJ L. QJ QJ QJ QJ O
I- «*- E J- i-J3-DQ.
3'i-3 3 C X
to QJ -M t/> to CO re QJ
O CD O O CD
CLCCMQ. Q.CI^CO
x re x x ta s^
LUS-LDQJ UJS~O-t->
QJ J=
0 +J O QJ
ro >> o *-* o jz o
i^- ^~ /^ v/ re oo 4-^ 4-^
S- i O QJ « -
3 re o re s- i i CM c^t
v) *^ 4-^ ^> re oo *^
4-> o en QJ
C C CO TD QJ 4-> i l QJJ3
i- QJ S- C O CD
\s 4_> 3 s-reo s-3
D Q- C 3 QJ T3 O
QJ "C X O t/) ^ C CO 3
IO r OJ i- O QJ i
O3H-CEQ- JOC-
CL o o; !-!- o re o to
X O "U ^ fi c~ *r c^_
OJ 3 tO tO -O O 4-> 3
re i "o i to re o
QjOJoca;3c\j ra i~ .c
e- ^ C re ^ O E QJ 3
I re -r- j= i So o:-oco
QJ i " QJ 1 It- to
o toojio'Ooo ijDreoto
re EH- QJ-JZ-i-CeC X 1- QJ
4 >^ ^ O g QJ JZI C ^ re (J QJ O CO ^s O
s_ jo ro cnjC4->Qj QJ z 4->CL4->o
3 CLtO'i-4-> E OI/) OJ O -i- J-
to-o aijc c «reco j=T3 i-n.
OJt-O 4-> Q) re I/) <4- to 4->O)QJO
c4->orea;caj xJi-reoj E-c-r-jco
r-ro M-JCCOSM-CSE' 4-34->reJC
**s E ^^ ^ H~ (/) 4-^ oretocore O(/i E 4^
l/l *^ C^ 3 CJ QJ * If- E I/I QJ
-4-> o to s_ jo ro c c ro o ro c
Ot/lt-t .Q. QJtO'i-S-S- O C -i-
(/) QJ QJ X7 t» O re £Z to 4 4 4-^ re (/) "O 4^
O to jo cn c c OJ reS C4-
fS f(j C re S QJ QJ E ^3 CM c\j f (/) QJ '*~
XSO'i-JZOi-OOOJEE 3QJS- O-J=
QJ 4->4- i QJ ro 3E to O O- ~ T3 i. 3 to «/l
ro J=4-4-O OO 3O re
CO QJ i T3 4-> T3 4- i_T3 Q.O OCX) OJtojri-COQJ
JCJ-LUCOC'i-3CXir5OCT> JZO OJ=S-
1 reo.reJore'Di/)(OQJC\iooi i » CLIO 4-> 4-> re
re c
QJ O QJ
J- 0 >
re c c_> o
OJ t S
QJ > QJ C
O O J3 00 CO O
re 2 r^ i- c
4- C T3 CO U, 3
J- O i CNJ Q to S-
3 E= 3 O O O
V) O O h- O.4-
QJ S 4-> X
C J= 00 QJ C
i- 4-> to -o r»» o to
^ s- co ro r- - i.
to OJ QJ to CM re4->QJ
i- ^ o E re ^
CO QJ $- CLT3 t S- S.
J=J=OXC QJ 3 O
H- S S QJ re Q -0 2
3-70
-------
to be half since it was assumed that the nonwoven garments these workers con-
tact are 50 percent pulp/50 percent textile fibers. The surface areas con-
tacted by nonwoven garments and masks were assumed to be half of the face,
and the entire palm and finger surfaces. Nonwoven garments worn by the
medical workers were assumed to be used as a covering over clothing or other
cloth garments. No data were available for exposure frequency and duration
except for clerical workers and managers. All other exposure durations were
based on engineering judgment and general knowledge of job related tasks
involving the handling of paper and nonwoven products. The skin contact area
for workers who are required to handle sheets of paper was assumed to be 20
percent of the total of palm and finger surfaces of both hands. These values
were derived from studies done by NCASI on typical commercial users of paper
products. The equation for handling dry material was used for commercial
users of paper since they handle the dry paper. This equation is presented
in Equation 16. Table 3-40 summarizes the variables and results for dermal
exposure for commercial users of paper and nonwoven products.
Several of the job categories were combined because exposures were
assumed to be similar. In Group 1, accountants, auditors, architects, libra-
rians, archivists, and duplicating and mail/message distribution personnel
were assumed to have similar exposures; Group 2 is made up of lawyers, judges,
computer programmers and operators, record processors, management, and miscel-
laneous administrative support personnel. Secretaries, stenographers, and
typists make up Group 3; Group 4 includes teachers and sales workers; and
Group 5 includes medical workers.
Equations 10 and 11 are used to calculate TEQ and percent exposure due
to 2378 TCDD. Table 3-41 presents daily lifetime average daily the TEQ and
3-71
-------
TABLE 3-40. ESTIMATED DERMAL EXPOSURE TO 2378 TCDD AND 2378 TCDF
FOR COMMERCIAL USERS OF PAPER AND NONWOVEN PRODUCTS
2378 TCDD
Variable3
2378 TCDD/2378 TCDF
concentration, ppt
(DC)
-Group 1
-Group 2
-Group 3
-Group 4
-Group 5
Weight of the dry
paper, g (PW)
Surface area of the
dry paper, cm2 (PS)
Low
0.1
0.1
0.1
0.1
0.05
4.5
600
Rate of transfer 0.0005
from the paper to
the skin, h l (R)
Percent 2378 TCDD/2378
TCDF available for
dermal absorption,
percent (%AD)
Skin surface area, cm2
-Group 1
-Group 2
-Group 3
-Group 4
-Group 5
Exposure duration,
h/day (ED)
-Group 1
-Group 2
-Group 3
-Group 4
-Group 5
Dermal exposure, mg/day
-Group 1
-Group 2
-Group 3
-Group 4
-Group 5
25
(S)
63
63
38
63
338
6
4
3
2
8
(DED) .
3.5x10 ::
2.4x101:7
1.1x10":.
1.2x10^3
1.3x10"
High
49
49
49
49
24.5
4.5
600
0.0005
25
75
75
45
75
350
6
4
3
2
8
2.1x10"}}
1.4xlO"f;
6.2x10" 9
6.9x10" i
6.4X10"11
2378 TCDF
Low
0.25
0.25
0.25
0.25
0.25
4.5
600
0.0005
25
63
63
38
63
338
6
4
3
2
8
8.9x10
5.9x10
2.7x10
3.0x10
3.2x10
High
2,620
2,620
2,620
2,620
1,310
4.5
600
0.0005
25
75
75
45
75
350
6
4
3
2
8
-14 -9
1 i Y i n
-14 -10
":? 3.3x10":^
"f^ 3.7x10 Q
"ir3 3.4xlO~y
Reference
Table 2-5
Table 2-5
Table 2-5
Table 2-5
Table 3-42
NCASI 1988c
NCASI 1988c
EPA 1989c
EPA 1989c
Table 3-42
Table 3-42
Table 3-42
Table 3-42
Table 3-42
Table 3-42
Table 3-42
Table 3-42
Table 3-42
Table 3-42
} Calculated
| Calculated
! Calculated
Calculated
Calculated
(continued)
3-72
-------
Group 1 includes accountants, auditors, architects, librarians, archivists,
curators, and duplicating and mail/message distribution occupations.
Group 2 includes lawyers, judges, computer programmers, computer operators,
record processing, management, and miscellaneous administrative support
occupations.
Group 3 includes secretaries, stenographers, and typists.
Group 4 includes teachers and sales representatives and workers.
Group 5 includes medical workers who may come in contact with nonwoven
products.
3-73
-------
TABLE 3-41. ESTIMATED TOXICITY EQUIVALENTS AND PERCENT EXPOSURE
DUE TO 2378 TCDD FOR COMMERCIAL USERS OF PAPER FROM DERMAL EXPOSURE
Daily exposure,
mg/day
Lifetime
average dai]y
exposure,
mg/day-Kg
Variable3
Low
High
Low
High
Toxicity equivalents
-Group
-Group
-Group
-Group
-Group
1
2
3
4
5
4
3
1
1
1
.4x10
(29)
.0x10
(29)
.3x10
(29)
.5x10
(29)
.6x10
(29)
-14
-14
-14
-14
-13
1
8
3
4
4
.3X10"10
(2)
.7xlO"U
(2)
.9xlO"U
(2)
.4xlO"U
(2)
.IxlO-10
(2)
2
1
7
8
8
.5xlO"16
(29)
.7xlO-16
(29)
.5xlO"17
(29)
.3xlO"17
(15)
.9xKf16
(29)
8
5
2
3
2
.9x10
(2)
.9x10
(2)
.7x10
(2)
.0x10
(2)
.8x10
(2)
-13
-13
-13
-13
-12
" /"*»*» i i »-i 1 £tf*r*Titfinf* ^xsmiM^«ii'i^f> -itift£±s*v*r> <«tA^«t*4^^^*+>r* 1^Wv*^w**i^«rI>
archivists, curators, and duplicating and mail/message distribution
occupations.
Group 2 includes lawyers, judges, computer programmers, computer
operators, record processing, management and miscellaneous adminis-
trative support occupations.
Group 3 includes secretaries, stenographers, and typists.
Group 4 includes teachers and sales representatives and workers.
Group 5 includes medical workers who may come in contact with non-
woven products.
Values in parentheses are percent exposure to 2378 TCDD.
3-74
-------
percent exposure due to 2378 TCDD from dermal exposure for commercial users
of paper and nonwoven products. Table 3-42 presents the assumptions and
uncertainties in the variables used to calculate the daily and lifetime
average daily dermal exposure for commercial users of paper and nonwoven
products in Table 3-40.
3.2 PERSONAL PROTECTIVE EQUIPMENT
Requirements for use of personal protective equipment vary from plant to
plant. Use of protective equipment such as protective clothing or gloves for
minimizing exposure to PCDDs and PCDFs through dermal contact was not men-
tioned in the literature; however, chemical-resistant gloves and other cloth-
ing are worn in pulp and paper manufacturing plants for protection from
caustic and other corrosive chemicals (EPA 1989). Many plants provide respi-
ratory devices for worker protection in emergency situations such as chlorine
leaks (Soklow 1984). No information could be found regarding the extent of
use of personal protective equipment such as dust masks or respirators in po-
tential dust areas in the pulp and paper industry. At one papermaking plant
studied by NIOSH, workers who performed the blowdown operations wore protec-
tive dust masks during this task. The other workers not performing this
operation usually retreated to an unaffected area during the blowdown opera-
tion. The amount of dust inhaled by workers may be decreased through the use
of better ventilation systems, wet methods or vacuums for cleaning dusts, and
well-sealed dust masks (UPIU 1989).
3.3 METHOD OF ABSORPTION/INHALATION
The methods for dermal absorption of PCDDs/PCDFs fall into two catego-
ries: the transfer of PCDDs and PCDFs from the pulp through the sweat medium
to the skin surface, and dry contact between the pulp or paper and the skin
3-75
-------
o
r
LU
fV
33
CO
O CO
0- 1
X 0
LU ID
0
JO
-.
LU O
t-i a:
1 LU
Z. 5.
< O
H * ^
a:
LU OC.
C_>0
z u.
^"1
LL.
o a
Z CJ
«c t
CO 00
z r»»
O CO
I-H CM
1-
G- ^^
§^>*
^^
co
co a
.a ro a.
co > E
C 3
O QJ co
CO i CO
n3 -O fO
QJ »r
a: co 4-
co O
0
o.
o c
QJ O
M v-
co *->
«- 0.
u E
0 3
C/) (/>
en en
^^ fO
>*
u
^
r-
CO
4_>
t-
O!
U
c
CO
to E
E QJ (-> QJ
r- S- L.
4-^3 VO 3
CO -CO
"M" O V£) O
0. Q.
M- X >4- X
O QJ O OJ
E S- E S-
3 QJ 3 Q)
£ 4-> _E 4->
X QJ X QJ
fD S- 10 S-
S CD 2: en
i- S-
QJ QJ Q; QJ
"D 1 Cn <_> -D 1 CT; U
X> i X C COO "C i X C COO
QJ 3 QJ "^ *~ ^V- 4-1 "CJ QJ 3 Q* *^~ ^ 4 4^ ^3
COO M-4->S- C COO <4_4->S- C
O 2 4-1 O 3 CD CO CO O ^ 4^ C 3 QJ CO CO
D- C "O _Q CO f> QJ Q- C "O J3 1/1 CO QJ
XCOQJC cOCOi « XcoQJC cCCOi
QJ QJ (j JQ (4 C QJ QJ co *""*» QJ QJ O co *4 C QJ QJ CO *^*-
S-i- O -i- S- r E CM i-S- O-i-S-i ECM
QJCOQJE ^:(JcOQJCO QJcaQJE ^^UcOQJOO
CO CLr CO CO C E *l- CT) CO DLI CO CO C E **- CTl
cCQJ COQJ-'- i t COQJ COQJT- i i
O O O Q- i- QJ i- S- UUOQ.S-QJ &-S-
IfOO cOXr-COOM- ICOO CO^TT3OO<4-
4-* ^ t~4 ^K- ^- ^~ C}~ (4 C 4_> C^ (~H (f. ^_ ^« C^. 1^-. $-
COJ- OCO 3 O COi- OCO 3 O
1-3QJ QJ OCMCM-O 1-3QJ QJ Ocjco-O
OCO"DQJU «5EEC OtO"OQJO »?EEC
~£ 3S-COCO (J (J QJ 2 3&-catO U U QJ
C i 3 >4- -O CO Q. C r 3 M- "C fO Q.
QJ-i-Ocoi-CQJOOO QJ-i-Ocoi-CQJOOO
f ^s C O 3 CO S- If) CO *"* ^ vx c O 3 CO I- LO CD *"*
1 COT- Q.CO.C COCMOO » I COT- D.CO.C COCMCO «
CO QJ COOQJCO QJ COOOJco
i-O. C U l»-QJeti OQJ O t- QJ U QJ
i «*^ O O Ci-co
i 3 QJQ-r- **->> COZ"DQJcO M->> COZ"OQJCO-
cOQ.t-i-O4-> l-^S4J«4-v_,cs_ to i-^D4->S -Ci- C
i- QJOOcO 3 Ci- COQJQJ- 3 CJ- coa'QJQJ
i- 4-> .C f- 1 i- (/)-OO)3cO H-OC CO-DQJ3CO <«-c_)E
QJC4JQJ 4J QJOtO-O^Clt-coaj QJOCO-O.C<4-COO
4JQJOS.COC C4Ji- C Cn-i- »1- E C 4-J S- C Cn-i- H- 5
COO QJr^-QJ r-cOQJi-CO'f-'Ol-O i-cOQJi-co-r-'Di-
ES-4->^:coo -^Ea-QJJC-c 32 ^; E Q- QJ -c ^: 3*0
QJCI CMC CO -i- CT: QJtO COv- CD QJCOC
CO.QJ O 4-> LD C -C QJ -C X) 4-> LD C JT QJ ^T CO
QJ U QJO "OCOCM->-4J^:4->QJC TJCOt l'f-4->.C4->QJ
>OS-*^ QJ QJ "+- O 1 ^=CO QJ QJ 4- O 1 .CCO
O LO Q) CO 4-> LJ_ « CO QJ .O 4->4-> CO Q) J2 4->4->-
2 Q-r Q-O OtO^STD C CO OCO.CJ-U C C
C<4- COM-OOI O-ca CM-«QJC- O-CO CH-«QJCQJ
OOO'r-OI to X2OCOO - COQJC X2OCOO - CO QJ E
C LO i- 3 QJ 4-> OOJOJOJCO QJ 4-> OQJQJ CO
QJ QJM-CO CO EcOCOi-2E'C CO EfOCOS-Sco-O
Qj-CJ'CJ4-Ji r--.CO QJQJi ii QJCOD-4-> C QJ QJ < i QJOOD-4J C
g*" to c CO CO CO CO g~ y^ 1 1 1 fQ ^ Q^ QJ QJ <+_ {Q ^ ^ ^i i (Q c fy* QJ Q« M CO
1 E CO CO^£4->CO
o i- QJ r^. t_ r O to 3 QJ CO 3 QJ
Q CO 2 O O- O O Q
OS- CS-3QJO CS-OJO
c_54JLn -i-CDO^O 'i-CD-jOO
t- C ^^ S- H- -^ r
QJ D- CO QJ tD T3 CO QJ T3
CO a 3 i- i 00 Ll_ S- r CO U-
coo£ ^^cocoo ^ *~ " "> o
CMOtS 1 2 CO 2 CM r 1 2 2 CM h-
T3
QJ
C
O
u
3-76
-------
^"N
o
0)
3
C
r
4J
C
o
(J
^.x
CM
^f
1
ro
tu
CO
ja re Q.
fO ^^ ^E
C 3
O CD CO
CO l CO
tO JO tO
O) -r-
o: to «*_
CO O
o
Q.
o c
CD O
4-^ *f~
re 4->
r- O-
0 E
O 3
co co
CO CO
«t re
>}
4-J
c
^
re
+*
L»
CU
s_
CO 3
CO
V£> 0
O.
«f- X
O CD
E S-
^3 (D
E 4->
- re
X CD
re S
s: en
(D X CD
"O 1 O^ QJ -g"
T3 i X C 1 1
CU 3 CU - X: 4-> C I- S-
COO <4_ 4-> c -i- O O
O 3 4-* O CU * ^t~ *4
a. c TD xi o -a "o
x re cu c s- re i N N
s- s- o CLX: o u u
CD ro CD E 2
CO O-i re if) CL> O O
recu re cu CM x: re LO o
O O CO *""* S 4-^ CU CM CO
i re o re co s.
4-> <+_ , i i+_ 3 o re o x>
COS- O to f 4-> 4-> C
S- 3 CD CD Q. CD re
O CO "O QJ O CU (J CU
3 3S-recoS-racoco
c p 3 tf *o 3 4 re cu
CU'r-OCOi-CCOl-CUi
^C ^^ C ^D ^t ^3 ^5 Z3 1^ fO
t** ^0 *^ D- ^0 «^Z ^^. ^0 C«) £*
t 4 "O
0) oo c:
o u- a> «=c ro
fO O U O +> 1
C^. >^ fQ ^^ C CIJ *t
S- XI +-> M O) T3 O !-
3 CS- U ro ro XI CD
co-e>O)3coi_CD4- x:
CDOCOTDCDX:S-CD-(->
C -M J- CO. 3 X:
i-racus-re a>co4->c
-x: E Q- CD x: LO x: CD
CO'i- Cn CM4->C4->O)
»-> to c x: -i- c S
*^t CO CM *r 4-^ CO O ^^ Cl) 4^
CD CD 4_ O 3 4-> CO CO CD
CO CD X3 i CD XI
O CO X) -O O.CUXIS.
Q. ro C C|_ S- en CL
^) ^5 ^5 CO
O $ CU CM
re to
^fr** ^o ^3 ^O
s- a. c
3 o, x re
CO 3 CD
o o
C S CU r *
i- (U X) (_>
to a
3 X
^5 P^ OJ
^f «
^*^ QJ
cu x:
S- C 4->
3 CU
CO CU CO
0 X CU
r"» -) ' ^
x ai -
LU X) (->
00
(D
x: o
C ^J~
«^
CU
CU r*"»
en
C T3
re i
S- 3
0
C
X> 'I-
CU CO
x: -o
p ai co
^§3
O co O
CO -C
c re
O CO
t- CO
4-> re cu
re 5 X3
S-
3 CU O
^0 t- "^^
3
CU to i i
x: o LU
t Q.D-
c
0
^
4J
re
l- to
3 S-
a cu
^X
CD S-
S- O
Z3 ^C
to
O rH
O.
X 0-
CU 3
0
re o
j^ j^
CU O
Q M-
*
r"
CU
2>
0)
r"~
O CU
r> S-
r
J 3
i- cr
cu cu
f j_
4-> S-
X) CU
*4- r- O-
o 3 re
0 0.
4-J l^.
r- tO O
i- 0)
^O *r- O>
*O *^" *r-
t~ ^^ p^
CU 4J C
x: (j re
M re x:
cu
c:
re
1- CM
-o o
i 4->
3
O LO
^
0
i. C
3 CD
CO CD
O 2
r"* 4-3
X CD
LU XI
00
CU
f Q
^ * 4->
C CM
"~ CU
en
>
CU
.C T3
4-> CU
.»-§
O CO
to
c re
o
r- tO
4-> re
re 2
3 CD
^O ^~
3
cu to
x: o
CU
L.
3
CO
o
CL
X
CU
(U
^
4->
CO i
CD CU
E >
f-
i- O CU
co re s-
co X) 3
s- o o-
3 !-> CU
o s-
x: s_
i- -O
x: 3
CD 4-> O
-Q 2
<+-
O O CO
+J QJ
4- -
1 1 l 4J
LU re >-
r O.O. XT >
c
0
r-
4->
re
s- to
^D 4-
v
i_
cu
o.
re
o.
*i
o
en
.,
^ .
a
c
re
x:
cu
c r~~
re
S- CM
o o
i 4->
3
o r^*
^
^^
CU
s- c
3 CU
CO (U
0 S
X (U
00
cu
[ * 4-3
C CM
(U
en
C "U
re i
S- 3
O
CU 5
o C
re o
O 4->
co re
re i-
i
x
cu ^^
^^
cu
-C T3
4-> CU
O CO
CO
c re
»~ CO
4-> re
re s
3
CO r
CD CD
^ ^
r- CU
v
CO
S-
3
CU
CD i- O.
o - re
c cu o.
r- x: "o
CO 4-> i M-
3 O
10 (f- o
s- o X en
3 C
O 4_ io -
X: r CU r
re - t3
co x: 4-> c
re
cu c > x:
xi re !-
x: 4-> CD
O 4-> U J-
4-> re
to 3
i i co xi cr
LU CU O QJ
1 Q.Q. i -r-J S-
C
o
4->
re
S- CO
o cu
j^
cu s-
s- o
3 f.
CO
O CO
a.
X Q.
CU 3
0
r S-
re cj
^ «
cu o
<*> H_
^.^
o
CD
3
C
4->
C
Q
U
3-77
-------
a
cu
c
r
C
o
(J
^^
CM
^^
1
CO
LU
CO
^^
1
co
4_>
i
3
co
CU
S-
c
0
CO
4_>
O
cu
c^
tl-
LU
CU
o
c ^z
ro O
CU - -r-
i S- 4J
.£> ra CL
rO > E
C 3
O CU CO
CO i CO
r- Q.
o E
O 3
CO CO
CO CO
^
4\J
C
c cu
ro S-
S- CM 3
CO
T3 O O
i 4-> Q.
3 X
O «d- CU
2
o cu
cu -c
S- C -M
3 CU
CO CO CO r
O S CU CU
CL4-> E >
X CU M- CO
LU O2 4-1 r
CU
J= O
C i 1
*~ cu
Ol
c -o
ro r
S- 3
0
CU 2
r
-Q C
ro O
C !
O 4-> CO
> C CO CL
.a -r- ^ -o
CO CO 4-> r ^-
J= T? 3 O
+-> cu to 4- O
E S- O 2 0>
*»- 3 3 C
O CO O M- CO !-
co jc i cu i
C ro ro >- "O
O CM .C 4-> C
r- CO < rO
+-> rO -C
«O 2 -Q ro -r-
S- J= 4-> CO
3 CU O +-> 0 S-
0 $- 4-> ro -r-
3 10 3
CO CO i < CO A CT
JZ O LU CO O CO
I a. a. i <-> i-
c
o
4J
ro
1- CO
3 S-
-0 CO
CO i.
S- O
3 2
CO
o **
a.
x CL
CO 3
0
r $_
ro U3
£ j_
CU O
O M-
CU
C7^ CO ^W
c s-
ro i I 3
S_ co
O 0
0 4J CL
3 X
O LO CU
2
CD a>
CU -C
S- C 4J
3 ai
CO CO CO i
O 2 CO CO
ca.4-> e >
X CU -r- CO
lil o 4-> i
CO
c
r- X3
CO "3
CD O
C 2
rO CO
S- C S-
O 3
CO «- O
r 4^ P"
J3 ra
ro S- O
C 3 «-
o -o
CO O
ro CU 4-»
CU -C
1
X
0) >>
X> CU
CU S-
t~ T3 «r
4-> CO 4->
E C
M- 3 CO
O CO
to cu
C ro .C 4->
O 4-> M-
r- CO >
4-» (0 CO -C
rO 2 ^ to
c
3 CO O S-
-a $- 4J 3
3 O
CO to t > -C
-C 0 LU
1 0.0. CO
c
o
4J
ro
S- to
3 S-
TJ CO
CO S-
S. 0
3 2
to
o in
CL
x a.
CO 3
o
ro t3
S- S-
cu o
Q <+-
3-78
-------
surface. Several factors affect the skin's ability to absorb PCDDs and
PCDFs, including skin barriers whose effectiveness are a function of age,
damage, or disease; increased PCDD/PCDF concentration and surface area con-
tact; or washing and rubbing of the skin. Absorption can also vary because
of differences in skin thickness, and diffusivity for different areas of the
body.
The amount of dust that workers inhale depends on several factors such
as airborne concentration, the amount of time spent in the contaminated area,
the particle size of dust and the proportion of breathing between nose and
mouth and the volume of inhaled air. The method of inhalation, either
through the mouth or the nose, can also affect the amount of dust inspired.
Once a dust particle has been inhaled, four different modes of deposition can
occur. Dust particles can deposit in the airways of the head and neck re-
gion, in the trachea, or in the lung; or they can be completely exhaled from
the lungs without depositing within the body.
3-79
-------
SECTION 4
CONCLUSIONS AND RECOMMENDATIONS
PCDDs and PCDFs are formed during the production of bleached pulp,
thereby resulting in a potential for worker exposure to these chemicals in
the production, processing, and commercial use of pulp, paper, and paper
products. Studies have shown that the use of chlorine and chlorine-based
bleaching agents could result in the generation of PCDDs and PCDFs such as
2378 TCDD, 2378 TCDF, and 1278 TCDF. This report focuses on 2378 TCDD and
2378 TCDF. Concentrations of PCDD and PCDF isomers have been detected in the
bleached pulp and in the paper products themselves. Results from the 104
Mill Study showed that PCDD/PCDF concentrations in bleached pulp ranged from
0.10 to 49 ppt for 2378 TCDD and 0.25 to 2620 ppt for 2378 TCDF. The mean
concentrations expressed as TEQ values for bleached pulp were 22.2 and 17.0
ppt for the Cooperative Dioxin Screening Study and 104 Mill Study, respec-
tively. TEQ values represent the relative toxicity of 2378 TCDF with respect
to 2378 TCDD, and were calculated by using Equation 1. The Cooperative
Dioxin Screening Study had much fewer pulp samples than the 104 Mill Study (9
compared to 199), but the mean TEQ values were similar.
The kraft pulping process, which comprises 88 percent of all the
bleached pulp processes, was the main focus of this report. Pulp and paper
mill workers may be exposed to 2378 TCDD and 2378 TCDF primarily via three
routes: 1} dermal contact with the bleaching wastewaters, bleached pulp or
paper products; 2) inhalation of particulate containing 2378 TCDD/2378 TCDF
4-1
-------
generated via paper dusts which are created during converting, rewinding,
sizing, pulp-fluffing, cutting, or other operations; and 3) inhalation
of 2378 TCDD/2378 TCDF volatilized from pulp and paper mills.
Although considerable data have been collected on PCDD and PCDF concen-
trations for pulp, sludge, and wastewaters in the pulp and paper industry,
exposure data for PCDDs and PCDFs are nonexistent. This is in part because
of a lack of a validated sampling and analytical method for measuring expo-
sures. Because of the lack of available data to determine inhalation expo-
sure from volatilization, PEI resorted to modeling techniques based on a
number of assumptions in order to estimate inhalation and dermal exposures to
2378 TCDD and 2378 TCDF. A range (i.e., low and high values) of exposure and
risk estimates are presented for each industry/worker scenario and exposure
route.
One of the models used in this report for estimating exposures to vapors
utilizes a mass balance approach to estimate worker exposure for specific
activities (e.g., for pulp testers during sampling). A second approach is
used for workers in a general area (e.g., bleach plant operators, utility
operators) and is based on estimating a maximum 2378 TCDD/2378 TCDF partial
pressure available for inhalation. In addition, the quantitative effects on
volatilization of 2378 TCDD and 2378 TCDF due to binding with organic matter,
and from interference due to other chemicals present in the pulp or paper
were not available, and hence, not included in the calculations; thus, the
inhalation exposure values provided are worst-case estimates. Some exposure
estimates are based on the assumption that TCDDs, TCDFs, pulp, and water
mixtures have two phases - an aqueous phase and a solid or pulp phase.
Furthermore, TCDDs and TCDFs were assumed to reside only in the aqueous phase
of the mixture.
4-2
-------
Data were available on the amount of dust generated from the pulp and
paper industry. These concentrations were below the OSHA nuisance dust
o
standard of 15 mg/m . No data were available on the amount of 2378 TCDD and
2378 TCDF in the pulp or paper dust; therefore, it was assumed that the
concentration of 2378 TCDD and 2378 TCDF in the bleached pulp was equal to
that in the paper and pulp dust. This approach results in an estimate of
worst-case exposure levels for 2378 TCDD and 2378 TCDF.
There were no data available on dermal exposures for workers in the pulp
and paper industry. PEI estimated exposures based on two CPSC models. These
models consider the partitioning of PCDD/PCDF from the appropriate matrix
(e.g., soil, sludges, paper) to a liquid (i.e., water, skin soil, urine,
blood) and percutaneous absorption of PCDDs and PCDFs from the liquid. One
model pertains to the handling of wet pulp or paper, while the other model
pertains to the handling of dry pulp or paper. The extent of dermal exposure
to workers varies depending on the handling of wet or dry material and the
duration of the exposure. PEI assumed worst case exposure durations when no
data on the duration was available.
Table 4-1 summarizes the 2378 TCDD and 2378 TCDF daily inhalation and
dermal exposure levels estimated in Section 3 for workers involved in produc-
tion, processing, and commercial use of pulp, paper, and paper products.
Table 4-2 summarizes daily toxicity equivalents, lifetime average daily
toxicity equivalents and the percentage of 2378 TCDD of these exposures
estimated in this report for pulp and paper mill workers and commercial users
of paper and nonwoven products. Appendix B presents the methodology for the
calculation of average and population risks for workers involved in the
production, processing, and commercial use of pulp, paper, and paper prod-
ucts. Table 4-3 summarizes the average risk and population risks based on
4-3
-------
co
o
o
a:
0.
fV Q£
O LU
U. Q-
<:
CO 0-
UJ
^~ \^
as:
ct ID
O Z
U. CO
Q CO
O LU
1 0
O
OO 0£
r»» CL
ro
CM "
111
L1J
o a:
-H
LL. 0
O LU
>- _J
Q£ O
is
co co
C£
UJ
»-i a:
1 O
LU
CO
«£
>1 »
c s^
ft) --».
3 "4- W>
cr o >>
a> ro
I- "U
u_ «.
o >^
4^ O T?
ro --^
Q ^"
L. .C
ftl Ol
i- u- 3:
1 §
ro oo
o r*-
I R S
ai
Is
£
3 cn
l/» !-
o Q a:
CL O
X O
ft) *-
>) CO
f f-*
-.- CO
o 2
1
ft)
a.
£»
ft)
u
t/l
o
a.
x
UJ
4- U.
o a>
o o
Z 2
k.
o
Ol
ai
4-)
IB
u
1
o
CM
CM
°i
O
x
**
CM
^
i
O
X
CM"
CM
O
x
O
CM
CM
'o
X
o
CM
C
o
^J
ro
r^
f-
4->
ro
o
i
c
0
ro
d
^
ro
t/i
o
k.
oj
c o
3 C
*-> ro
o ^~
*o a.
c o
ro ro
E 0)
3 1
O-
«t O O
in m
Z CM CM
^
Z CM i-i
CM r>.
1 (
Z X X
O ro
CM .-H
to CM
»-< CM
i i
COO
Z X X
VO O
f-t \O
*t CM
-i CM
i i
< S 2
^ x x
CO I-H
to in
r-» CM
*O N
3
O "^
4-> ro
t. ^-
2. >
c c
0 0
ro | 2
^ S £
ro
CO
i/i
w
Of
s
a.
3
CL.
\
^ O 0
***. i/> i/>
Z CM CM
^
z to to
1 1
coo
z x x
CO CM
t t-.
in
O o
^-v X X
Z CM CM
«« r*-
CO CM
« V2 72
*^ x x
z fo -<
in to
in CM
i i
0 O
* 1 ^H
«C x x
<-* to
ft*
4->
^ S
ftl 4->
4-» ro
CM
in
i
o
***. x
CM
CM
1-H
1
o
"** X
z -<
^4
in
o
«C X
"^-s. CM
CM
L-
S
4-J
I
QJ
ro
*^
u
'M
i-
Q.
C
0
4-)
I i
c a>
M M
m -*^ in tn -^. m
CM 3E CM CM Z CM
< ^
CM Z CM CM Z CM
CM
1 II 1
o «c o o *t o
x ac x x z x
^H m ^-» O
f-i t-. ^-i CM
f) CM CO tO
O o>
4-> 4-»
c ro c ro
0 E O E
4-* ft) 4-» ft>
M ro M ro
» 3 r- 3
to +J ^B 4^
» fc. f t.
o ro on
> CL S. 0.
it it
c c c c
o o o o
m CO
O >t
ro *^-
O 3
c c
- -r- fc.
"- ~O -D *
>> W
5 SO
i
0
CM
CM
T
0
X
"-J
V- 1
ro
i
0
X
^
^.
1
O
CO
« 1
f^
* 1
o
r^.
CO
c
0
4->
1
c
o
A3
ro
c
Io
to
o
«
L. 0
t- <0
3 k.
4-- ftl
U CL
ro o
i!
IS 0>
fc z
o.
2 '
^ s
Z CM
^
Z CM
CM
«C 0
z x
CM,
to
1
< O
z x
^
^.
1
o
z «-<
CO
to
'o
Z
4J
E
ftj
10
3
'M
U.
O-
1
c
0
ro »
T
f-J
^
t-
ro
o
>
i
c
o
ro
5
c
in
^
CM
l
L.
O
ro
ro
E
ft)
ro
3
U
'£
ro
CL
i
O
ro
ro
c
O
CM
**
c^
O
x
CM
ro
i
O
x
CM
^
1
O
m
in
^.
0
^~
cr^
ro
ft)
-------
cr
0;
o o x
Q. ID
x -o
CL.C
w"""
<3>
I
CT>
O
O
X
ro
2 2
X X
v r*
o
at
o
u
o
4-)
D
O
X
§
fc
§
f
L,
1
o
&. VI
££
Z
<
Z
«t
«t
z
^
z
^
z
c
o
re
*^-
re
o
i
c
o
4->
IO
c
1
CM
&-
o>
§
re
k.
4)
i
*
o
in
CM
OO
1
o
X
CM
CO
'T*
O
X
O
in
i
o
X
o*
CO
m
i
0
X
O
CM
w
^J
re
E
re
3
U
4^
U
re
CL
I
C
o
re
c
0
in
CM
00
o
X
01
in
ro
i
O
x
^
o
*T
o
X
,_J
CO
1
o
X
^
i
ci
«c
z
c
0 fc-
re L.
1- O
£*
o.
o *-
re
C k.
QJ O>
g£
? °
I '
0 O
CM CO
00 VO
__,
oo -»
1 1
O 0
X X
CO CO
t-H t-H
co m
i i
O 0
X X
O 0
in « i
o co
i t
o o
X X
CM OJ
CO IO
1 1
o o
X X
o CM
CM <"
i-
^j
E
at
u
4-*
i-
s.
o
f c
c aj
i-* O
o
CM
VD
O
X
1 1
^
<
o
X
°J
oo
f 1
o
X
CM
<
1
O
X
in
CO
I
OJ
o
1
Ot
CO
(0
*
CM
L-
01
V)
=3
re
i- Q.
U 3
i!
u
o
in
CM
^~
o
1
o
X
f^
*r
i
o
X
^
m
-*
i
o
X
,_J
<4-
1
O
X
CM
re
a>
8
CO
CO
vo
CM
CM
CL
C0
i
O
IT)
CM
ro
O
i
O
X
CO
CO
*
1
o
X
r-.
CM
CM
O
X
CM
vo
^>
i
O
X
,_,
i
a
§
g
vn
en
CL
3
e
CD
1
0
in
CM
CM
O
r- <
0
X
CO
*r
0
X
o
ro
CM
1
O
X
Oi
vo
^J-
1
o
X
CM
,_«
i
o
i
in
§
a.
1
1
O
in
CM
CM
01
1
O
X
CO
ro
o
x
CM
CO
1
o
X
vo
CO
1
0
x
CO
^^
i
01
o
1
CO
r-
in
CL
1
1
in
3
O
CD C
re *o
l/l r
l/l «
QJ QJ
E <-J
"-». V>
^ E
1 j
"O C
QJ
- c
re E
u
r CT1
CL c
3 -r-
X) QJ
s g
L.
* Q.
i/>
i- vi
S L
re o
3 QJ 4-»
u t- u
* o X)
*J L P
v) o a.
> re c
* l_ QJ
0 CL O
1- O jt
10 L. . O
QJ VI C
l/l *-> t.
C 3 QJ f
r- E "tf «r-
J- 0 0 Jt
re u jt
U V) 4J
.O " 4-* X) U
i- vi vi c re
r- 1_ -^ re *>
O» CL c
E >> vi o
v> E +-> QJ y
U U X) - C
QJ t7> C +«> -
^ £ *° 2 QJ
£ CL C E
O V) QJ O
re QJ QJ QJ
4-> .£ t- >,
V," | & & I
O O en O
4-> U O V) f
r- V» C QJ Jt
O * C QJ
re QJ - m w i-
cn+J QJ
in 3 CL in C t-
4-> '«-^ 3 QJ tQ O
C 0 jt
re * o t- vi
4-* tn i/i o re L. >
3 O QJ 4-> , i- i- o -
r c>rereo.QjQjQj
ja re cu. CL v» 4J £
U vtuminininin
Q. 3 3 > 3 D 3
c -r- c re c c c
O 3 4->
Z t-t -O CM V) m *a- in
II CL tl CL'C CL ex CL
re A
ut
CO
-------
LU CO
cc. i
ID o
CO Z3
0 Q
a. o
X CC.
LU D-
LU cc.
CD LU
-i
h~ O
>- LU
-j s:
f
CD
i__i
LU CO
2£ co
» i LU
H- O
LU O
LU cc.
H-, Q.
_i
«
CO LU
t CC.
2» ^
LU |
1 O
> Lu
«-< 13
=} Z
1 1 1 ^^
>- Z
1 H-l
^H
0 O
l i LU
X >
O I
1- 0
>- z
J t 1
frM|
<; CO
Q «V
LU
U. i^
OQC
O
P"*
* *
u *> fc.
c u ^>
3 «t- i/i i/i
?°g.J-
u x -o
1*. ft) -I -
§ £~
v 3 >>
o .*T z
* s *
^ E ^
4-> *- >,-^
C 4-* . cn
^ ^-^ E
> J _J
3
4)
"u «T J=
X 3 »-
O trt I
*~ P
x «a
ai -o
^ ^
S |
ft)
o.
£
t
8.
X
UJ
vl
t.
ft)
fc.
o
^
O
(J
O
^
o
CM
CM
CM
t <
1
O
X
*£>
«-<
CM
*-*
O
X
^4
o
I CO
00
CM
o
"ts
X O
CM
C
o
(a
IT*
r-
4*J
g
1
C
O
1)
JC
5
VI
1.
o
IQ
L.
ft)
O) O.
C 0
3 C
a-
3 j;
C U
(O ID
^ '
^ s
Z CM
^
Z CM
in
i
«£ O
Z X
°i
^H
O"i
o
E
**
*c
*^
u
£
1-
s.
1
c
0
O f
f E
o
o
CM
,-.
CM
1
O
X
*o
CO
in
CM
1
CD
X
CO
OO ^*"
T S
00
rn£-
^4
CO
CSJ H
i ro
oo
x o
w
c
0
V CM
1 1
«C O O
Z X X
CM cn
t-« v
CO CM
1 1
O O
*^» X X
Z f** ^H
«> V
CM O
1 1 00
o o o
Z CO1 CO*'
in o
1 1 CO*
o o o
< *X V *X 0
^. CM' CO-*-
^H r*.
1.
4_>
I 0
O) '-^
>O Kl
3
o »-
£ *J
1 g
1 1
c c
0 0
*O ID
5 1 2
-« o
CO
CO
L.
o
ID
ft)
o.
o
4J
3
1
4-6
«C 0 O
-in in
Z CM CM
«£
3: V£> CM
^r ro
1 1
«c o o
Z X X
CM r-*
r** f**
o o
«t » -«
*-* x x
^ LO*
CM O
1 1 CM
0 OO
CO t-H
JQ 2
o o'co
« "x v fx°*
z *
CM i-l
L.
4_»
4-*
1 1
a> *3
4-> fO
10 N
*3 »
U -f-
f- 4^
4-» «
1 s
1 1
c c
o o
5 c £
o
VD
t-
o
£
&
o
c
c'u'
B&
-O r~
3
0,0.
3 I
(O
*^
- '
-f CM
-H ^H
1 *. 1
O ro o*
t-H O *f. «-^ t*-
X -^ X V
"~? °- z to'*^
t t f-H
t.
ft)
4->
C fO
0 E
*J ft)
N (Q
» *3
r- (J
4-> -r-
*O o.
1 1
c c
0 0
-c £ E
^^ ^-t O
o
oo
+J
p
"i
cn
c
*o
M
r
t-
+J
o
>
1
c
o
^
t 1
r-
u?
to
o
l_
1- O
££
3 1-
4-> OJ
U Q.
a o
c c
i;
S- ft)
£3
«O 1
«£ ^0
*-» t
2: x
CO
ro
1
o
«f ^H^^
Z 00^
CM
12
o -
^. *>(. V
z in-
^-1
t.
ft)
M
i
ft)
rt)
*^
u
4->
o
ex
c
o
^ j
i i o
"S
1
*J
c
o
u
-------
o
0)
age
re, Duration Frequency
of of
exposure exposure
gh (h/day) (days/yr)
11" i/> C" I
X >-,
«3 &> Qj *O
i/> E "C
*-> *- >»*-»
C *-» * CT>
4j QJ '~ E
i **- *O ^
3
CT
QJ
"o Qj ^
X 3 »-
3 S
o- >>
X fO
r^lf
Da
Job category workers Exposure type Low
ooo ooo ^ o o ^ o o ooooo
m in m mmm **^inir> ^ m in in in v> m m
CM CM e\j CMCMCM z CM CM ZCMCM CMCMCMCMCM
« n* 49- IO -* *O ***» CO CO "^-- CO ^ ^D *> rO CM CM
Z Z
CM -* CM CM O CM OCM .-H^T rOPOrOPOCM
III III II II I 1 1 1 1
ooo ooo «soo «too ooooo
XXX XXX ZXX ZXX XXXXX
^JmCM CMCMCO «-»v ^-«i-. cOincMPOCM
iii iii ii ii i i i t i
ooo ooo < o o «too ooooo
XXX XXX ZXX ZXX XXXXX
CM PO 10 co P^ co *f oo *T c^ in t** in PO &\
i^r^VO ^->CMCn *-* v-t ^(CM CMi-HP^COCO
0 OO O O ^J2^^I^2
1 - . 1 1 l-~-.il II II 1 1 1 1 1
O CM O O O CM O O OO OO OOOOO
XOXCMXCM XOXCMXCM -^.XCMXCM -^.XCMXCM XCMXCMXCMXCMXCM
O'» .o-> .....
CM- r*. PO ro - ^-in CM^» ,-t.-i >- co ro < «
*J-POPO «*CMPO coco roio «*-W^-«»-PO
1 ' 1 1 1 « - II II II 1 1 1 1 1
X'XCMXCM X X CM X CM -^XCMXCM ^. X CM X CM XCMXCMXCMXCMXCM
CM o P*"> - CM * co o co ' co *»-* ZUI-*^PO^-' z m * ' CM * * ^ w^ o* - PO - m N-- *o -
csj .-» < PO^-I-H CM CM CM in ^-PO*-I<-H<-I
i- L. k- t-
cm en c ro CQ
0£= O E OE OE
«} 4_> «4-> O N(O
*~^ f-»*3 ^*^ IE ^
f t. i i_ i- i u-
O«0 OiO O*O O«O
>cx >cx > ex. >cx
II II II II
cc cc cc cc
OO OO OO OO
ill iii iii iii iiiii
C C Qj C C QJ C C QJ CCO* O> QJ QJ O> QJ
, 0 « « 0 ^ « O , _- 0 OOODQ
CM co en in popooc^cft
VI t 1 * . * *
C CM V£) in *
O CM i
4-*
t- ex v»
o t. o c
*j o t- o i- u
<0 -M O> QJ *- Ol in
L. t) C ^ 4-» ^ k.
O» L, f- fc. m k- O>
O, QJ 4-> O k. O v\
0 % fc* g.*
"o >r o^- p ^-«CMPO^Fin
C V> C fl9 *O *O
QJ *J Ok. c k. «- cx o. ex ex CL
O *^ QJ CJD % C5 £ O ^ CD U C3
i I 41 O l Oiitii
o
u
CM
a
(U
4-7
Ul
CO
«I
c
o
-------
in p
O> OJ
r I
u i- o c
oj CT c *-
l/> O
t- U. k O
C 4» O»
** -C >>
- 3 O. O. (O
C I £ E
O O C7> O
+J U (/> O £
- C C *
O - O QJ
3 V> ^- *j m
<0 (U 4-> VI t-
.
3 3 VI
*
!T*,S
O t-»
j 4-> at «
o ^> o w w *^-
0) U X Q- O «D *O
* u a)
J3 « * 3 M W E
ia in tn
o vi c vi vt t/t t/i
a> o ^
-------
TABLE 4-3. SUMMARY OF OUTER BOUNDS OF AVERAGE INDIVIDUAL AND POPULATION
RISKS BASED ON TOXICITY EQUIVALENTS FOR WORKERS INVOLVED IN MANUFACTURING,
PROCESSING, AND COMMERCIAL USAGE OF PULP, PAPER, AND PAPER PRODUCTS
No. of
Job category workers
Pulp manufac-
turing
- Bleach plant 434
operators
- Pulp testers 433
- Utility 433
operator
Pulp drying
- Pulp drying 160
operator
Average risk
Exposure type
Inhalation-vol-
atilization
Inhalation-par-
ticulate matter
Dermal
Inhalation-vol-
atilization
Inhalation-par-
ticulate matter
Dermal
Inhalation-vol-
atilization
Inhalation-par-
ti cul ate matter
Dermal
Inhalation-vol-
atilization
Inhalation-par-
ti cul ate matter
Dermal
Low
4xlO"7
(0.08)
N/AC
2xlO~13
(47)
IxlO"19
(0.03)
N/A
2xlO"12
(47)
IxlO"6
(0.08)
N/A
4xlO~12
(47)
2xlO"U
(0.03)
N/A
9xlO"10
(29)
High
5xlO"7
(0.08)
N/A
5xlO"10
(4)
2xlO"15
(0.002)
N/A
3xlO"9
(4)
IxlO"6
(0.08)
N/A
7xlO"9
(4)
2xlO"7
(0.002)
N/A
3xlO"6
(2)
Population risk
Low
4xlO"6
N/A
3xlO"12
IxlO"18
N/A
2X10"11
IxlO"5
N/A
4xlO"U
7X10"11
N/A
4xlO"9
High
5xlO"6
N/A
6xlO"9
3xlO"14
N/A
4xlO"8
2xlO"5
N/A
7xlO"8
9xlO"7
N/A
IxlO"5
(continued)
4-9
-------
TABLE 4-3 (continued)
No. of
Job category workers
- Pulp drying 80
utility
operator
Paper manfac-
turer
- Wet-end 10,667
operator
- Dry-end 12,445
operator
- Utility 8,888
operator
Paper convert-
ing operations
- General 129,000
worker
Average risk
Exposure type
Inhalation-vol-
atilization
Inhalation-par-
ticulate matter
Dermal
Inhalation-vol-
atilization
Inhalation-par-
ti cul ate matter
Dermal
Inhalation-vol-
atilization
Inhalation-par-
ticulate matter
Dermal
Inhalation-vol-
atil ization
Inhalation-par-
ticulate matter
Dermal
Inhalation-vol-
atization
Inhalation-par-
ticulate matter
Dermal
Low
2xlO"U
(0.03)
N/A
2xlO"13
(29)
2xlO"U
(0.03)
N/A
2xlO"13
(47)
3xlO"U
(0.03)
2xlO-10
(29)
2X10'10
(29)
5X10'11
(0.03)
8xlO"9
(29)
3X10'10
(29)
N/A
4X10'10
(29)
4xlO"10
(29)
High
2xlO"7
(0.002)
N/A
5xlO-10
(2)
2xlO"7
(0.002)
N/A
5xlO-10
(4)
4xlO"7
(0.002)
IxlO"5
(2)
7xlO"7
(2)
7xlO"7
(0.002)
8xlO"5
(2)
IxlO-6
(2)
N/A
5xlO"5
(2)
IxlO"6
(2)
Population risk
Low
SxlO"11
N/A
5xlO"13
5xlO"9
N/A
7X10-11
IxlO'8
6xlO"8
6xlO"8
IxlO"8
2xlO"6
6xlO"8
N/A
IxlO"6
IxlO"6
High
4xlO"7
N/A
IxlO"9
6xlO"5
N/A
IxlO"7
IxlO"4
5xlO"3
2xlO"4
IxlO"4
2xlO"2
2xlO"4
N/A
2xlO"!
4xlO"3
(continued)
4-10
-------
TABLE 4-3 (continued)
No. of
Job category workers
Nonwoven
operations
- General 15,000
worker
Commercial
users
- Group 1 2,639,000
- Group 2 26,933,000
- Group 3 5,004,000
- Group 4 14,095,000
- Group 5 793,000
Exposure type
Inhalation-vol-
atization
Inhalation-par-
ticulate matter
Dermal
Dermal
Dermal
Dermal
Dermal
Dermal
Average
Low
N/A
4X10'10
(29)
8xlO~13
(29)
7X10-11
(29)
5xlO"U
(29)
2X10"11
(29)
2xlO"U
(29)
3xlO-10
(29)
risk
High
N/A
3xlO"6
(2)
3xlO"9
(2)
3xlO"7
(2)
2xlO"7
(2)
8xlO"8
(2)
8xlO"8
(2)
8xlO"7
(2)
Populati
Low
N/A
IxlO"7
3X10'10
5xlO"6
3xlO"6
IxlO'6
2xlO"6
2xlO"5
,b
on risk
High
N/A
IxlO"3
IxlO"6
2xlO"2
IxlO"2
5xlO"3
6xlO"3
5xlO"2
Values in parentheses are percent exposure to 2378 TCDD.
Values represent cases per year.
N/A = not applicable
Group 1 includes accountants, auditors, architects, librarians, archivists,
curators, and duplicating and mail/message distribution occupations.
Group 2 includes lawyers, judges, computer programmers, computer operators,
records processing, management, miscellaneous administrative support
occupations.
Group 3 includes secretaries, stenographers, and typists.
Group 4 includes teachers and sales representatives.
Group 5 includes medical workers who may come in contact with nonwoven
products such as garments and masks.
4-11
-------
lifetime average daily toxicity equivalents for pulp and paper mill workers
and commercial users of paper and nonwoven products.
There are several data needs for developing more refined estimates of
worker exposure to PCDDs and PCDFs in the pulp and paper industry. Some
areas in which additional information is needed include the following: 1)
characterization of worker activities in pulp (nonwovens) converting opera-
tions; 2) the frequency and duration of potential dermal and inhalation
worker exposure to PCDDs and PCDFs in the pulp and paper manufacturing,
converting, and nonwoven fabric and textile fiber industries; 3) the extent
of use and effectiveness of personal protective equipment and engineering
controls in this industry; and 4) the number of workers in each job category
potentially exposed to PCDDs and PCDFs. Additional information is also
needed on the potential for exposure to pulp and paper workers during infre-
quent activities such as bi-yearly cleaning of grinding pit and paper roll
residuals which may contain high PCDD/PCDF concentrations (Sullivan 1989).
There are some ongoing as well as planned studies which may clarify some
of the uncertainties found in this report. A NIOSH study to characterize
worker exposure to PCDDs and PCDFs at up to 4 kraft pulp/paper mills is
currently underway and is expected to be completed in 1990. The 104-Mill
Study has been completed; however, the data that was collected needs to be
analyzed with respect to plant operating parameters such as production rate,
type of wood used (e.g., softwood, hardwood), and quantity of bleaching
chemical used to determine variations in 2378 TCDD/2378 TCDF concentrations
(and hence risks) as a function of plant operations. A follow-up study to
the 104-Mill Study is being performed in early 1990 by members of NCASI, the
American Paper Institute (API), and participating pulp mills. This study
will provide new PCDD/PCDF concentration data at selected pulp and paper
4-12
-------
mills which will reflect advancements in PCDD/PCDF reduction. Elimination of
petroleum-based additives such as oil-based defoamers and pitch dispersant
has been achieved at some pulp mills. Also, reduction in chlorine usage
during the bleaching stage has been pursued at some mills with favorable
PCDD/PCDF reduction. This new study should provide some insight on the
amount and extent of PCDD/PCDF reduction in the pulp and paper industry.
Also, this new information should provide updated PCDD/PCDF concentrations
for the exposure calculations (Grant 1990). The 25 Bleach Line Study con-
ducted by NCASI will be completed in early 1990 and will provide PCDD/PCDF
concentration data for 25 bleach lines in 31 mills. PEI is also awaiting
additional information on workforce characterization, converting operations,
and production data from the API which should assist in filling some of the
data gaps. Site visits to pulp manufacturing, papermaking, and paper con-
verting operations would also provide additional insight on the potential for
exposure to workers when performing different activities.
4-13
-------
REFERENCES
(Beck 1988)
(Bond 1989)
(Census 1987)
(Census 1988)
Beck, H.t et al. Occurrence of PCDD and PCDF in Different
Kinds of Paper. Chemosphere, 17(l):51-57. 1988.
Personal communication with Gary Bond, NCASI. July 1989.
U.S. Department of Commerce, Bureau of the Census.
Statistical Abstract of the United States, 1988. 108th
Edition. Washington, D.C. December 1987.
U.S. Department of Commerce, Bureau of the Census. Current
Business Reports. Pulp, Paper, and Board 1987. Washington,
D.C. November 1988.
(Clement 1981) Clement Associates, Inc. Mathematical Models for Estimating
Workplace Concentration Levels: A Literature Review. Pre-
pared for the Economics and Technology Division of the U.S.
Environmental Protection Agency. October, 1981.
(Clement 1982) Clement Associates, Inc. Methods for Estimating Workplace
Exposure to PMN Substances. Prepared for the Economics and
Technology Division of the U.S. Environmental Protection
Agency. October, 1982.
(CPSC, 1989)
(Cunningham
1990)
(Drivas 1981)
Personal Communications between Mike Babich, Consumer Products
Safety Commission and PEI Associates, Inc. on equations for
estimating dermal exposures from wet and dry pulp, paper, and
sludges. October 1989.
Personal communication with Neil Cunningham, James River
Corporation. January 1990.
Drivas, P. S., Simmonds, P. G., and Shair, F. H. Experimental
Characteristics of Ventilation Systems in Buildings. Current
Research 6:609-614.
(Eitzzer 1986) Eitzer and Hites. 1986. Referenced in U.S. Environmental
Protection Agency Study Under Consent Agreement. 1989.
Section 2.0 Chemistry and Fate of Dioxins and Furans.
(EPA 1984) U.S. Environmental Protection Agency, Chemical Engineering
Branch. A Manual for the Preparation of Engineering
Assessments. September 1984.
(EPA 1988) U.S. Environmental Protection Agency. U.S. EPA/Paper Industry
Cooperative Dioxin Screening Study. EPA-440/1-88-025. March
1988.
R-l
-------
(EPA 1989a)
(EPA 19895)
(EPA 1989c)
(Federal
Register
1989)
(Felder 1978)
(Festa 1989)
(Grant 1990)
(Hanmer 1988)
(Hawks 1989)
(Hawley 1987)
(Kimbrough
1984)
(Kirk-Othmer
1981a)
(Kirk-Othmer
1981b)
Correspondence between Christina Cinalli, Environmental
Protection Agency (EPA) Exposure Assessment and George Heath,
EPA Engineering Technology Division on calculation procedure
for lifetime average daily exposures, percent exposure due to
TCDD and risk. October 1989.
U.S. Environmental Protection Agency. Study under Consent
Agreement. 1989. Section 2.0 Chemistry and Fate of Dioxins
and Furans.
U.S. Environmental Protection Agency. Interagency group from
EPA and Consumer Products Safety Commission. Common Assump-
tions for the Assessment of Human Dermal Exposure to Polychlo-
rinated Dibenzo-p-Dioxins and Dibenzofurans. July 1989.
Federal Register, Thursday January 19, 1989. U.S. Department
of Labor Occupational Safety and Health. Title 29 Code of
Federal Regulations Part 1910.0000.
Felder, R. M., and Rousseau, Elementary Principles of Chemical
Processes, 1978. John Wiley and Sons. New York, New York.
Personal communication with John Festa, American Paper
Institute. August 1989.
Personal communication with Terry Grant, Weyerhauser Paper
Company. January 1990.
Hanmer, R. W. Environmental Protection in the United States
Pulp, Paper, and Paperboard Industry: An Overview of
Regulation of Wastewater Under the U.S. Clean Water Act.
Water Science Technology, 20(1):1-7. 1988.
Personal communication with Ron Hawks, PEI Associates, Inc.
July and August 1989.
Hawley. 1987. Hawley's Condensed Chemical Dictionary,
Eleventh Edition. Van Nostrand Reinhold Company. New York,
New York.
Kimbrough, R., et al. Health Implications of 2,3,7,8-Tetra-
chlorodibenzo-p-dioxin (TCDD) Contamination of Residential
Soil. Journal of Toxicology and Environmental Health,
14:47-93. 1984.
Kirk-Othmer. 1981a. Encyclopedia of Chemical Technology.
3rd Ed., Vol. 16. John Wiley & Sons, New York.
Kirk-Othmer. 1981b. Encyclopedia of Chemical Technology.
3rd Ed., Vol. 19. John Wiley & Sons, New York.
R-2
-------
(Kuehl et al.
1987)
Kuehl, D. W., et al. 1987. Environmental Contamination by
Polychlorinated Dibenzo-p-Dioxins and Dibenzofurans Associated
with Pulp and Paper Mill Discharge. Biomedical and
Environmental Mass Spectrometry, 14:443-447.
(Lammers 1989) Personal communication with Don Lammers, Curt G. JOA, Inc.
December 1989.
(McCubbin
1989)
(NCASI 1987)
(NCASI 1988a)
(NCASI 1988b)
(NCASI 1988c)
(NIOSH 1983)
(NIOSH 1985)
(Nonwovens
1989)
(OTA 1989)
(Podoll 1986)
Personal communication with Neil McCubbin, Independent
Consultant. July and September 1989.
National Council of the Paper Industry for Air and Stream
Improvement, Inc. Assessment of Potential Health Risks From
Dermal Exposure to Dioxin in Paper Products. Technical
Bulletin No. 534. New York. November 1987.
National Council of the Paper Industry for Air and Stream Im-
provement, Inc. Risk Associated With Dioxin Exposure Through
Inhalation of Paper Dust in the Work Place. Technical Bulle-
tin No. 537. New York. January 1988.
National Council of the Paper Industry for Air and Stream
Improvement, Inc. Results of Measurements of Airborne
Particle Size Distributions in Paper Converting Areas.
Technical Bulletin No. 554. New York. August 1988.
National Council of the Paper Industry for Air and Stream
Improvement, Inc. Assessment of Potential Health Risks to
Pulp and Paper Mill Workers From Dermal Exposure to Dioxin in
Bleached Pulp, Paper, and Pulp-Based Products. Technical
Bulletin No. 549. New York. June 1988.
Anderson-Nichols and Co., Inc. Control Technology Assessment
in the Pulp and Paper Industry. Prepared for the U.S.
Department of Health and Human Services, National Institute
for Occupational Safety and Health under Contract No.
210-79-0008. April 1983.
NIOSH Pocket Guide to Chemical Hazards. U.S. Department of
Health and Human Services. NIOSH Publication No. 85-114.
September 1985.
Nonwovens Industry, Vol. 20, No. 5, Rodman Publications, Inc.
May 1989.
U.S. Congress, Office of Technology Assessment. Technologies
for Reducing Dioxin in the Manufacture of Bleached Wood Pulp.
OTA-BP-0-54. May 1989.
Podoll, et al. 1986. Referenced in U.S. Enviornmental Pro-
tection Agency Study under Consent Agreement. 1989. Section
2.0 Chemistry and Fate of Dioxins and Furans.
R-3
-------
(Popendorf
1982)
(Schroy 1984)
(Soklow 1984)
(Sullivan
1989)
(UPIU 1989)
(Versar 1982)
(Voss 1988)
Popendorf, W. J. and J. T. Leffingwell, 1982. "Regulating of
Pesticide Residues for Farmworker Protection". Residue
Review, 82, pp. 156-157. Springer-Verlog, New York.
Schroy, J.M., Hileman, F.D.; Chens, S.C., 1986. Physcial
Chemical Properties of 2,3,7,8-Tetrachlorodibenzo-p-dioxin.
ASTM Special Publication 891. (Aquat. Toxicalogy Hazard
Assessment, 6th Symposium: 409-21
Soklow, R. Paper Production and Processing Occupational
Exposure and Environmental Release Study. EPA-600/2-84-120.
July 1984.
Personal communication with Claire Sullivan, United Paper-
workers International Union. July 1989.
United Paperworkers International Union (UPIU), AFL-CIO/CLC.
The Dioxin Data: What Does It Mean? The Paperworker,
17(7):18-21. July 1989.
Versar 1984. Exposure Assessment for Retention of Chemical
Liquids or Blends. Prepares for the U.S. EPA under contract
No. 68-01-6271.
Voss, R. H., et al. Some New Insights Into the Origins of
Dioxins Formed during Chemical Pulp Bleaching. Pulp and Paper
Canada, 89(12):151-161. 1988.
(Wong 1983) Wong, K. 1983. Unpublished EPA report.
R-4
-------
APPENDIX A
104 MILL STUDY: 2378 TCDD AND 2378 TCDF
CONCENTRATION IN BLEACHED PULP ON A DRY BASIS
A-l
-------
104 MILL STUDY: 2378 TCDD AND 2378 TCDF
CONCENTRATIONS IN BLEACHED PULP ON A DRY BASIS
Company and location
Alabama River Pulp
Claiborne, AL
Alaska Pulp Corp.
Sitka, AK
Appleton Papers, Inc.
Roaring Springs, PA
Badger Paper Mills, Inc.
Peshtigo, WI
Boise Cascade Corp,
Jackson, AL
DeRidder, LA
St. Helens, OR
Rumford, ME
Wallula, WA
International Falls, MN
Bowater Corp.
Catawba, SC
Calhoun, TN
Brunswick Pulp/Paper
Brunswick, GA
Buckeye Cellulose (P&G)
Perry, FL
Oglethorpe, GA
Champion Intl . Corp.
Lufkin, TX
Courtland, AL
Quinnesec, MI
Cantonment, FL
Houston, TX
Canton, NC
Chesapeake Corp.
West Point, VA
Consolidated Papers, Inc.
Wisconsin Rapids, WI
Container Corp. of America
Brewton, AL
Flambeau Paper Corp.
Park Falls, WI
Federal Paper Board Co.
Augusta, GA
Riegelwood, NC
Finch, Pruyn & Co., Inc.
Glens Falls, NY
Gay lord Container
Antioch, CA
Georgia-Pacific Corp.
Bellingham, WA
Crossett, AR
Palatka, FL
Woodland, ME
Zachary, LA (Port Hudson)
Gilman Paper Co.
St. Marys, GA
Gulf States Paper Corp.
Demopolis, AL
Harmermm Papers (IP)
Erie, PA
Selna. AL
Ranges in
2378 TCDD
38-43.0
0.7
1.0
4.5
9.1-11.0
5.3
4.2-6.5
17.0-116.0
56.0
NAa
2.1
7.7
1.6-8.3
0.5b
0.5b
4.9
3.5-23.0
Z-8
0.7-4.9
4.9
4.6-17.0
6.3
18.0-20.0
2.3
K
0.5b
2.4-7.9
3.2-4.3
k
0.3b
32.0
k
6.2D
6.0-19.0
0.5°
0.4°
5.2-27.0
2.8-3.7
5.2
6.4
2.1-4.7
pulp (ppt)
2378 TCDF
97-120.0
1.4
21.0
110.0-323.0
71.0-104.0
8.7
11.0-18.0
111.0-800.0
1380.0
3.3
53.0
2.9-12.0
2.5
0.9b
6.8
7.6-102.0
45.0-50.0
0.7D-4.1
6.8
5.5-27.0
14.0
79.0-83.0
4.5
k
0.9D
7.9-19.0
1.3-4.7
k
0.3D
969.0
449.0
59.0r308.0
0.9-2.4
0.9
78.0-632.0
6.8-12.0
20.0
22.0
21.0-22.0
(continued)
A-2
-------
Ranges in pulp (ppt)
Company and location
International Paper Co.
Bastrop, LA
Georgetown, SC
Jay, ME
Mobile, AL
Moss Point, MS
Natchez, MS
Pine Bluff, AR
Texarkana, TX
Ticonderoga, NY
ITT-Rayonier, Inc.
Fernandina Beach, FL
Hoquiam, WA
Jesup, GA
Port Angeles, WA
James River Corp.
Berlin, KH
Camas, WA
Clatskanie, OR
Green bay, WI
Old Town, ME
St. Francisville, LA
Butler, AL
Kimberly-Clark Corp.
Coosa Pines, AL
Leaf River Forest Products
(Great Northern Nekoosa)
New Augusta, MS
Lincoln Pulp/Paper
Lincoln, ME
Longview Fibre Co.
Longview, WA
Louisiana-Pacific Corp.
Ketchikan, AK
Samoa, CA
Mead Corp.
Chillicothe, OH
Escanaba, MI
Kings port, TN
Nekoosa Papers, Inc.
(Great Northern Nekoosa)
Ashdown, AR
Nekoosa, WI
Port Edwards, WI
Penntech Papers, Inc.
Johnsonburg, PA
Pope & Talbot, Inc.
Halsey, OR
Potlatch Corp.
Cloquet, MN
Lewis ton, ID
McGhee, AR
P.M. Glatfelter Co.
Spring Grove, PA
Procter & Gamble Co.
Mehoopany, PA
Scott Paper Co.
Everett, WA
Mobile, AL
2378 TCDD
5.1-6.3
1.9-17.0
11 ft O
NA
3.5-21.0
7.3-15.0
3.6
5.0-23.0
7.0-12.0
16.0-31.0
K
°'2b
°'3b
°'3b
0.6D
3.3c32.0
0.0-12.0
NAb
0.8D
13.0
4.9-6.4
1.2-3.7
h
0.3-11.0
3.6
16.0
4.8
h
0.3D
9.1
a
NAa
15.0-25.0
1.5
2.8-5.5
22.0.
0.4b
3.1
10.0
1.2-2.4
25.0-27.0
12.0-21.0
0.4-6.5
2.0
L.
0.3b
0.6-1.7
2378 TCDF
22.0-42.0
7.7-55.0
14.0-106.0
36.0-105.0
15.0
5.7-0-661.0
51.0-81.0
103.0-185.0
K
0.5°
3.8
0.6-0.9
2.1
41.0-1110.0
0.6-152.0
7.1
51.0
15.0-19.0
1.4-30.0
1.0-38.0
15.0
94.0
18.0
k
0.3b
59.0
39.0-116.0
25.0
12.0-27.0
283.0
4.1
38.0
41.0
5.0-7.9
147.0-153.0
59.0-83.0
2.2-18.0
1.1
L.
O.lb
0.8-2.2
(continued)
A-3
-------
Ranges In pulp (ppt)
Company and location
2378 TCDD
2378 TCDF
S.D. Warren (Scott Paper)
Hinckley, ME
Muskegon, MI
Westbroo, ME
Simpson Paper Co.
Anderson, CA
Fairhaven, CA
Pasadena, TX
Tacoma, WA
St. Joe Paper Co.
Port St. Joe, FL
Stone Container Corp.
Missoula, MT
Panama City, FL
Snowflake, AZ
Temple-Eastex, Inc.
Evadale, TX
Union Camp Corp.
Eastover, SC
Franklin, VA
Wausau Paper Mills Co.
Brokaw, WI
Westvaco Corp.
Covington, VA
Luke, MD
Wickliffe, KY
Weyerhaeuser Co.
Cosmo polls, WA
Everett, WA
Long view, WA
New Bern, NC
Plymouth, NC
Rothchild, WI
Willamette, Ind.
Hawesville, KY
1.9-8 5
0.3D
4.2-8.1
49.0
20.0
4.5-18.0
12.0
2.2
4-!b
O.lJ
0.7b
1.9-7.8
h
0.4D-2.4
1.1-5.4
h
0.1D
5.9-13.0
29.0
2.1-12.0
h h
0.3-1.0°
3.4-5.2
1.6-7.7
7.5
10.0-33.0
15.0
bL
u.^ -0.5b
10.0-37.0
1.0
16.0-30.0
2620.0
106.0
11.0-66.0
38.0
5.7
13.0
6.6
1.3
6.3-22.0
1.3-5.6
2.1-69
9.9
19.0-105.0
157.0
25.0-55.0
2.9-6.4
16.0-20.0
2.8-20.0
45.0
82.0-318.0
26.0
1.1-1.9
0 NA - Not available.
Indicates nondetectable.
Note: For pulp analysis, the EPA results do not accurately distinguish
between levels of dioxin and furan found in hardwood and softwood
pulps, so the lowest and highest levels reported are presented to
represent the ranges found at each mill.
A-4
-------
APPENDIX B
RISK ASSESSMENT METHODOLOGY
B-l
-------
APPENDIX B
RISK ASSESSMENT
This section presents the metholodogy for the calculation of risk to
2378 TCDD and 2378 TCDF. Unit risk is used to compare the relative potencies
of carcinogens. Potency is defined as the linear portion of a given dose-
response curve which is used to calculate the unit risk factors. On a curve,
the upper confidence limit for the extra risk calculated at low doses is
always linear. The slope (q*) is taken as the upper-bound of the potency of
the chemical (TCDD) in inducing cancer at low doses. The 95% upper confi-
dence limit of dose-response functions for the linear slope factor q* of 2378
TCDD is 0.156 kg- d/ng or 1.56 x 10+5 (mg/kg/day)"1. The derivation of this
factor is described in EPA 1984.
During the development of the slope factor an absorption factor of 55
percent was applied. The percent of the TEQ available for absorption was
incorporated into the equations in Chapter 3 for inhalation and dermal expo-
sures. The equation for calculation of average risk and population risk are
presented in Equations B-l and B-2, respectively.
AVGRISK = LTEQ x PF / AF Equation B-l
POPRISK = AVGRISK x POP / YEAR Equation B-2
Where:
AVGRISK = average risk for lifetime average daily toxicity equivalents,
unitless
LTEQ = lifetime average daily TEQ, mg/day-kg
PF = potency factor, kg-day/mg
AF = absorption factor, unitless
POPRISK = population risk for lifetime average daily toxicity
equivalents, cases/year
POP = number of workers in the population
YEAR = number of years for worker exposure, years
B-2
-------
The lifetime average daily toxicity equivalents (LTEQ) which were used
in Equation B-l were presented in tables from Section 3. Three types of
lifetime average daily TEQs were calculated in Section 3 for inhalation
exposure from volatilization, inhalation exposure from particulate matter,
and dermal exposure. The potency factor used in the equation was 0.156
kg-day/ng (EPA 1984). The absorption factor (AF) was estimated to be 0.55
(Farland 1987).
Table B-l summarizes the variables for the estimated average risk and
population risk for workers involved in production, processing, and
commercial use of pulp, paper, and paper products. The average risks and
population risks are summarized in Table 5-3. The following is an example
calculation for calculating average risk and population risks.
Lower limit for average risk for bleach plant operators from volatilization
AVGRISK = 1.4 x 10"12 mg/day-kg x 1.56 x 105 kg-day/mg/0.55
= 4 x 10"7
Lower limit for population risk for bleach plant operators from volatiliza-
tion
POPRISK = 4 x 10"7 x 434 workers/40 years
= 4 x 10" cases/year
TABLE B-l. VARIABLES FOR ESTIMATING AVERAGE RISKS
AND POPULATION RISKS
Variable Value Reference
Potency factor, kg-day/mg 1.56xlO+5 EPA 1984
(PF)
Absorption factor, unitless 0.55 EPA 1998b
(AF)
B-3
-------
REPORT DOCUMENTATION J- REPORT NO. 2.
PAGE EPA 560/4-90-015
4. Title and Subtitle
Estimated Worker Exposure to 2378 TCDD and 2378 TCDF in the
Manufacture, Processing, and Commercial Use of Pulp, Paper,
and Paper Products
7. Author's)
PEI Associates, Inc.
9. Performing Organization Name and Address
PEI Associates, Inc.
11499 Chester Road
Cincinnati, OH 45246
12. Sponsoring Organization Name and Address
U.S. Environmental Protection Agency
Office of Toxic Substances
401 M Street, S.W.
Washington, DC 20460
3. Recipient's Accession No.
5. Report Date
July 1990
6.
8. Performing Organization Rept. No.
10. Proiect/Task/Worfc Unit No.
11. Contract(C) or Grant(G) No.
(o 68-D8-0112
(G)
13. Type of Report & Period Covered
Final Report
14.
15. Supplementary Notes
EPA Contract Officer: Paul Quillen
EPA Work Assignment Manager: Nhan T. Nguyen
16. Abstract (Limit: 200 words)
This report assesses potential worker exposures and risks to 2378 TCDD and 2378 TCDF in
the production, processing, and commercial use of pulp, paper, and paper products. The
report identifies the ijob categories in each operation and examines worker exposure via
the following three exposure pathways: 1) inhalation of volatilized 2378 TCDD/2378 TCDF,
2) inhalation of particulates containing 2378 TCDD/2378 TCDF, and 3) dermal contact with
pulp, paper, or sludge.
Since no available personnel exposure monitoring data is available, various modeling
techniques and assumptions are used to estimate exposures. A range (low and high values)
of exposure and risk estimates are presented for each industry/worker scenario and
exposure route. The "low" and "high" exposures and risks are estimated based on the
lowest and highest dioxin TEQ concentrations, as reported in the 104-Mill Study, and
typical to reasonable worst-case assumptions, respectively.
17. Document Analysis *. Descriptors
b. Identifiers/Open-Ended Terms
c. COSAT1 Field/Group
18. Availability Statement
Release Unlimited
19. Security Class (This Report)
20. Security Class (This Page)
21. No. of Pages
137
22. Price
,ee ANSI-Z39.18)
See Instructions on Reverse
OPTIONAL ro«tl 272 (4-77)
(Formerly NTIS-35)
Department of Commerce
------- |