OCCUPATIONAL DERMAL EXPOSURE ASSESSMENT -
A REVIEW OF METHODOLOGIES AND FIELD DATA
FINAL REPORT
September 30, 1996
Submitted to:
Chemical Engineering Branch
Economics, Exposure and Technology Division
Office of Pollution Prevention and Toxics
U.S. Environmental Protection Agency
401 M Street, S.W.
Washington, D.C. 20460
Submitted by:
Science Applications International Corporation
11251 Roger Bacon Drive
Reston, Virginia 20190
Contract No. 68-D2-0157, WA No. 2-50
SAIC Project No.. 06-0758-07-5367-407
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TABLE OF CONTENTS
I. INTRODUCTION ....... !_!
A. OBJECTIVES ! 1-1
3. BACKGROUND 1-2
C. TECHNICAL- APPROACH 1-6
D. REPORT ORGANIZATION 1-10
II. DERMAL EXPOSURE ASSESSMENT METHODS . . . 2-1
A. DERMAL EXPOSURE MONITORING METHODS 2-1
1. Surrogate Skin Techniques 2-1
2. Removal Techniques 2-4
3 . Fluorescent Tracer and Other Light Sensing
Techniques 2-4
4. Surface Sampling Techniques 2-5
B. DERMAL EXPOSURE ESTIMATING METHODS 2-6
1. EAB Method 2-6
2. ORD Method ¦ 2-11
3. APPLICATION TO DERMAL ABSORPTION ASSESSMENT . . 2-14
III. SKIN SURFACE AREA 3-1
A. SKIN SURFACE AREA MEASUREMENTS 3-1
B. SURFACE AREA/BODY WEIGHT DISTRIBUTION DATA 3-3
IV. DERMAL EXPOSURE DATA FROM PUBLISHED REPORTS 4-1
A. Mixing of Dry Powder Materials 4-6
B. Bagging . . . . 4-7
C. Stacking . ' 4-13
D. Mixing of Powder with a Liquid 4-15
E. Liquid Mixing and Transfer ..... 4-21
F. Intermittent Contact . 4-31
V. DERMAL EXPOSURE DATA FROM PHED ¦ 5-1
A. OVERVIEW . . ' 5-1
B. DATA ANALYSIS PROCEDURES .' 5-2
1. Exposure Variables 5-2
2. Data Normalization and Correlation 5-2
3. Data Conversion, Data Quality, and Detection
Limit 5-4
C. GROSS- DERMAL DEPOSITION NORMALIZED BY QUANTITY OF
CHEMICALS FOR MIXING AND LOADING OPERATIONS .... 5-5
D. GROSS DERMAL DEPOSITION NORMALIZED BY EXPOSURE
DURATION FOR MIXING AND LOADING OPERATIONS .... 5-16
VI. EVALUATION OF AVAILABLE INFORMATION ON POTENTIAL
EXPOSURE 6-1
A. SUMMARY OF EXPOSURE ESTIMATES 6-1
B. ESTIMATE FOR DAILY POTENTIAL GROSS DERMAL RETENTION 6-1
C. COMPARISON WITH CEB METHOD PARAMETERS . . .• . . . .6-9
D. DATA UNCERTAINTIES 6-11
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TABLE OF CONTENTS (Cont'd)
VII. BARRIER EFFECT OF PROTECTIVE CLOTHING 7-1
VIII. CONCLUSIONS AND RECOMMENDATIONS 8-1
A. CONCLUSIONS 8-1
3. RECOMMENDATIONS FOR IMPROVING THE CEB METHOD .... 8-4
C. RECOMMENDATIONS FOR FUTURE RESEARCH 8-6
1. Work and Protective Clothing 8-8
2. Maximum Retention ,8-8
3. Effects of Washing 8-8
4. Chemical Loss Through Evaporation 8-8
5. Chemical "Loss" Through Dermal Absorption .... 8-9
.6. Skin Hydration 8-9
7. Transfer Rate from Surface to Skin 8-9
8. Activity Patterns 8-10
IX. REFERENCES 9-1
APPENDIX A
STATISTICAL DESCRIPTIONS OF ESTIMATED GROSS DERMAL
DEPOSITION NORMALIZED BY QUANTITY OF CHEMICAL HANDLED
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ACKNOWLEDGEMENT
Many individuals and organizations have been helpful in
developing this report; for their contributions the project
management extends its sincere gratitude.
Ms. Breeda Reilly and Ms. Beth Crowley were the EPA project
officers and Ms. Cathy Fehrenbacher was the EPA Work Assignment
Manager. The report was prepared by Science Applications
International Corporation (SAIC) under EPA Contracts No. 68-Dl-
0156, No. 68-D4-0098, and' 68-D2-0157. Dr. Ching K. Chen was the
SAIC Project Manager for this work assignment'.- The authors would
like'to thank Mr. Alan P. Nielsen of EPA's Office of Pesticide
Programs and Mr. Timothy Leighton of Versar, Inc., for the use of
the Pesticide Handlers Exposure Database (PHED).
Peer review was provided by Mr. Mark F. Boeniger, National
Institute for Occupational Safety and health';. Ms. Christine
Whittaker, Occupational Safety and Health Administration; Dr.
Richard A. Fenske,.University of Washington; Dr. Hans Marquart,
TNO Nutrition and Food.Research Department of Occupational
Toxicology, the Netherlands; Dr. Bert Hakkinen, The Procter and
Gamble-Company; Mr. Thomas D. Klingner, Colorimetric
Laboratories, Inc., and Dr. Franklin E. Mirer, United Auto
Workers. Dr. Kim-Chi T. Hoang, EPA Office of Research and
Development and Mary Katherine Powers, BPA Office of Pollution
Prevention and Toxics provided peer review input during the
development of the document.
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S'JMMARY 0? PEER REVIEW COMMENTS AND EPA RESPONSES
A peer review of'a draft of this document prepared before
June 30, 1994 was completed in August 1994. That draft document
was entitled "Occupational-Related Dermal Exposure Assessment
Methodology." It contained the same basic information, though
organized slightly differently, as in this final version of the
document. However, exposure data in that earlier draft were
presented in a different form: average exposure from published
reports and independently calculated arithmetic and geometric
means for various subsets of data from the Pesticide Handlers
Exposure Database (PHED) were used. The full peer review
comments can be obtained from the EPA's Chemical Engineering
Branch. The following is a summary of peer reviewer's comments
and EPA responses:
EPA Response eo Comment:
Peer Reviewer and Comment
Mark Boeniger, NIOSB
Suggested revisions to make soma of
the terminology more consistent
throughout the document. Provided an
update on NIOSH research and
suggested additional NIOSH and OSHA
documents Cor evaluation. Suggested
clarification on the scope of the
project, tabulations, and provided
comments to clari£y issue* discusaed
in the sampling methodology section
of the report.
Christine Whittaker, OSHA
Suggested to clarify the scope and
purpose of the document, consider
retitling the document to better
reflect the scope. Commented that no
new research is presented, although
the document clearly illustrates the
problems associated with assessing
dermal exposures in an occupational
setting.
We agree with the comments provided
which suggest additional
clarification and editorial review.
He have revised the report to make
the terminology consistent, and have
revised the document as suggested to
incorporate the clarifications. The
scope of the project was also
clarified as suggested.
We agree with the comments provided.
The document title was reworded to
more appropriately reflect the scope
and purpose.of the document. The
text was revised to better reflects
the scope and purpose as well. It
is hoped that this document, which
is the first of its kind for
industrial occupational
environments, will prompt additional
research into this important area of
dermal exposure assessment.
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Peer P.aviewer and Commons
EPA Response Co Comment
Tom Klingnar, CLI Laboratories, Inc.
Additional information regarding
limitations of the sampling
methodology, theoretical approaches
to predict K„ for organic solvents,
biological monitoring, and glove
permeation data were presented. In
addition, limitations of tha film
thickness method for liquids was
discussed. Suggested that exposure
duration for most of the cited
studies may not be comparable to
industrial exposures, and suggests
that pesticide re-entry is a closer
comparison of industry exposure
issues. Finally, suggested retitling
the document to better reflect the
scope and purpose.
Bert Hakkinen, The Procter 4 Qaable
Company
Recommended an expanded literature
search and numerous additional
references for inclusion; including
work by other Federal Agencies.
Suggested revising the tide to mora
accurately reflect tha scope and
purpose of the research. Provided a
great deal of additional information
regarding'the barrier effect of
protective clothing, tha OPPT's .
Exposure Assessment Branch (BAB)
DERMAL program, dermal deposition
rates from published reports, and
transfer of chemicals from fabric to
skin. A colleague with expertise in
dermal absorption and skin exposure
assessment also reviewed the document
and provided input. Suggested
additional information to provide
perspective on the use of the SPA's
Office of Research and Development
(ORD). Kj, approach, and discussion of
determination of K, values.
We agree with the comments provided.
A very thorough review of the
document was conducted, and the
comments were excellent. The
additional information was
incorporated into the document.
With respect to biological
monitoring, a detailed evaluation of
biolpcjical monitoring data is
outside the scope of this effort,
but it is discussed briefly in
several places in the document. The
reason for the exclusion is
primarily due to tha fact that
Chemical Engineering Branch (CSB)
only assesses dermal "exposure"
while another Division is
responsible for assessing potential
for "absorption" when evaluating
dermal exposure issues within EPA's
Office of Pollution Prevention and
Toxics (OPPT). Tha cited studies
were critically evaluated and
characterized with respect to
comparison to industrial operations.
As mentioned above, tha document was
retitled in response to comments
received.
We agree with the ccements and have
incorporated the relevant references
and additional information into the
report. A very thorough review and
excellent cannents were provided by
the reviewer. An expanded
literature search was conducted and
additional references were obtained..
The additional information was
incorporated into tha document. The
discussion of the ORD K, approach was
expanded, including determination of
K, values and experimental
methodology. The scope and purpose
of the document was clarified and
the title was changed to more
accurately reflect the content of
the document. Information available
on maximum skin loading of solids
and liquids was added.
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Peer Reviewer and Comm^nr r
Kui Mar quart, TOO, The Netherlands
Numerous additional references, many
from Europe, were recommended for
inclusion. Suggested revisiting the
methodology used to critically
evaluate and analyze the pesticides
exposure data in light of the recent
study by Van Hemmen which also
reviewed and evaluated pesticides
exposure data. Suggested clarifying
and clearly articulating the
conclusions and recommendations,
particularly use of the published and
PHED data in quantifying amount
retained on the skin. Cautioned on
the use of the PHED data due to
complexity and potential error in
calculation of statistical inference.
Suggested other areas for additional
research, including the effect of
washing the skin on the amount
available for penetration, and
collection of additional, data to
enable more accurate (less
conservative) estimates to be
developed. A colleague with
expertise in dermal absorption
reviewed the relevant portions of the
document and found them to be well
written. Provided specific comMnts
on the sampling methodology, cautions
against grouping of exposure
scenarios which may 'not be similar,
and additional information on the use
of barrier effect of clothing data.
Franklin ICirer, United Auto Workers
Suggested to include statistical
descriptors such as means, standard
deviations, and ranges to
characterize the exposure data from
published reports.
EPA Response to Commpnf ¦
We agree with the comments provided
and have incorporated them into the
document where possible. A thorough
review of the document and excellent
comments were provided by the
reviewer. The Van Hemmen study was
reviewed and found to be an
excellent addition to the report.
Additional references and
information from the study were
incorporated into the report. The
approach for analysis of the data
was revised; statistical analysis
within PHED were used directly. The
statistical approach used in Van
Hemmen's paper was adopted for this
document. The EPA's Office of
Pesticide Programs (OPP) has been
involved in reviewing the document
as it progressed to ensure
appropriate use of PHED database and
interpretation of data. According
to OPP, tha statistical calculations
in the PHED database are correct.
The additional areas for research
were incorporated and other comments
wera incorporated into tha document.
He agree with the conments and have
provided the ranges and means of
exposure data where available.
vii
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Peer Reviewer and Comment
EPA Response to Comment:
Richard fensks, Univ. of Washington
This reviewer was unable to review
and comment on the entire document,
but agreed to provide comments on
Chapters 3 and 7 of the document,
which address the evaluation of the
studies gathered from the literature
and evaluation of the applications of
the data. Numerous additional
references from Europe and the State
of California were suggested for
inclusion. Suggested a greater
clarity in the description of data
manipulation procedures, and
suggested a sample calculation with
some real data to add clarity.
Recommended to review a recent report
which suggests that soil loadings do
reach a maximum on the skin.
Provided reviews on the complexities
of the many issues associated with
dermal exposure assessment, and areas
needed further research. Questioned
why greenhouse studies were not
included within the report.
Expressed concern with the
normalization of exposures to 30-50
minutes per day as a standard daily
exposure period, which may be
appropriate for pesticides exposures,
but not for industrial exposures.
Suggested some additional references
for further investigation. Concurred
with the authors that the
extrapolation of data generated in
outdoor pesticid* application studies
to traditional industrial exposures
involves many assumptions and
uncertainties, and generally agreed
that the CEB values can be used.
The review of Chapters 3 and 7 of
the document was comprehensive and
excellent comments were provided.
The attempt to obtain additional
references from the State of
California was unsuccessful. The
data manipulation procedures in
Chapters 4 and 5 were clarified.
Additional evaluation of soil
loading data was conducted to help
interpret the data for predicting
the amount of solid retention in the
skin. Greenhouse studies were
excluded as most of the industrial
exposure scenarios evaluated by CEB
are not comparable to greenhouse
spraying. If greenhouse spraying-
type scenarios become more prevalent
in CEB assessments, additional data
will be compiled and evaluated.
Normalization of quantity retained
on the skin over a standard daily
exposure period or a standard daily
quantity handled was revisited and a .
revised approach was adopted.
viii
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OCC'JPArcwAL ;e?MAL iXPOSL'RE assessment • A review
I . INTRODUCTION
September 30, '996
A. OBJECTIVES
Dermal contact with chemical substances during industrial
operations represents a potentially significant route of exposure
for workers. Unlike other routes of exposure such as inhalation,
dermal exposure sampling methods and interpretation of monitoring
data have not been well defined. The only situation where dermal
exposure has been studied extensively is in pesticide operations.
Exposure is defined by the Agency as the amount of substance
contacted by the outer boundary of the organism integrated over
time (EPA, 1992a) . For dermal exposure, it represents the amount
of substance that contacts the.skin prior to any penetration.
Accurate assessment of dermal exposure hazards must account for
the complex mechanism of continuous deposition, retention,,
removal, evaporation, migration, and absorption at the skin
surface. However, there currently is no model that can describe
these processes adequately. As a-result-,-dermal exposure--has
been assessed by determining the amount of chemical deposited or
retained on the skin, or by determining the amount of chemical
that can be removed from the skin.
Because of a lack of field monitoring data on industrial
operations, the Chemical Engineering'Branch (CEB) of the EPA
Office of Pollution Prevention and Toxics uses a method based on
extrapolating an estimated quantity of chemical retained on a
unit area over the total exposed skin surface area to estimate
dermal exposure. However, only limited knowledge on the input
parameters and applications of this method exist. Consequently,
validation and improvement of the method are needed.
The objectives of this report are to:
e Provide a literature search of monitoring data on
dermal exposure; identify other methods used for'
predicting dermal exposure when monitoring data is not
available
• Evaluate the CEB method and revise or identify
additional values and input parameters (e.g., quantity
remained on the skin, skin surface area) for predicting
dermal exposure under various exposure scenarios;
• Make recommendations to improve the CEB method based on
the literature search and evaluation.
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otcuPAncm ijewai exposure assessment - * review
September 30, 1994
The field monitoring data available are almost exclusively
related to pesticide operations such as mixing, loading,
spraying, and flagging. When compared to typical industrial
operations, only the mixing and loading operations may find some
similarity with the corresponding industrial operations.
Therefore only dermal exposure data related to pesticide mixing
and loading operations are reviewed in this document. In
addition to presenting such dermal exposure data, several related
topics including dermal exposure monitoring methods, skin surface
area estimation, dermal absorption modeling, arid barrier effects
of protective clothing are discussed within the report. It
should be noted that for these topics, a comprehensive literature
search was not conducted, and the reader is referred to other
sources for additional information.
A review of available monitoring methods for assessing
dermal exposure is presented to provide an overview of the
difficulties and uncertainties involved in such monitoring. The
dermal absorption process and current knowledge on modeling are
discussed to reflect how they impact the exposure assessment.
The skin surface area at various anatomical regions of the body
is critical in estimating total dermal exposure. Thus, a review
of the historical practices and current recommendations on skin
surface area are presented. Many pesticide studies have included
the barrier effects of protective clothing, and a brief review of
the available data on this topic is presented.
Biological monitoring, which can be an important tool in
evaluating dermal exposure to some contaminants such as
polycyclic aromatic hydrocarbons and certain organic solvents, is
not addressed in this report. Recognized methods for conducting
biological monitoring are not available for the majority of the
substances evaluated by OPPT, and interpretation of biological
monitoring data in relationship to various routes of exposure is
often difficult.
B. BACKGROUND
The. Chemical Engineering Branch uses the following equation
for estimating dermal potential dose rate.(as the amount
available for absorption) (CEB, 1991):
D = SQC
where D = Dermal potential dose rate, mg/day
S = Surface area of contact, cm2
Q = Amount retained on skin, mg/cma
C = Concentration of chemical of concern, percent by
weight.
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OCCUPATIONAL 0E3MAL EXPOSURE ASSESSMEkT - A 3EVIEU
Sepcemoer 30, '996
The CEB method assumes chat a single contact with the
chemical results in the quantity retained on the skin for a
complete work day with exposure duration of 4 to 8 hours or
longer. It is also assumed that workers wash their hands at meal
break time and at the end of the shift. Additionally the CEB
method assumes that dermal protection, such as gloves,, is not
used by the worker to limit exposure. Therefore, the method
generates estimates of potential daily dermal exposure at the
hands for the sub-population of workers who do not use dermal
protection. The estimates provided by this method are believed
to be conservative (i.e., overestimates), and this is confirmed
by the evaluation of data as discussed in this document.
This dermal exposure assessment method is currently used to
develop bounding estimates of the potential dose in terms of the
amount of a chemical remaining on a worker's skin (usually
expressed in terms of mg/day) and available, for absorption, .after
the worker completes various common industrial activities leading
to occupational exposure. The dermal potential dose rate is
coupled with an estimate of the amount absorbed through the skin
to compute a predicted absorbed dose for purposes of risk
assessment. A bounding estimate is an estimate of individual
exposure or dose where the estimate is purposely constructed to
be higher than the individual in the distribution with the
highest exposure or dose. A bounding estimate is useful in
developing statements such as "the exposure or dose is no greater
than ." Bounding estimates are quite useful in screening
level assessments. However, a..bounding estimate cannot be used
for an estimate of actual exposure (EPA, 1992a).
Default input values for estimating the potential dose rate
on the hands have been developed for use in the above equation,
as shown in Table 1-1. The surface area of the hands is based on
Popendorf et al. (1983). The quantity of substance, remaining on
the hands and available for absorption is based on a laboratory
study by Versar (1984) . In the Versar study,, participants
immersed their hands in one of several liquids, or performed
other activities. The amount of. liquid retained on the hands was
then measured. The 1984 Versar 'study has been updated with the
most recent review dated 1992 (EPA, 1992c) . A summary of the
updated data on skin surface reteation rates in mg/cm5 is shown
in Table 1-2. The 1992 review followed a more rigorous treatment
of the data, however, the experimental subjects and procedures
still represent a significant source of variability.
As recommended in the CEB Engineering Manual (CEB, 1991) ,
dermal exposure- estimates should be adjusted by the following
factors when applicable:
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OCCUPATIONAL DERMAL EXPOSURE ASSESSMENT • A REVIEW
September 30, 1996
0
The concentration of the chemical in the mixture
(weight fraction)
The percent of the hand exposed if less than what would
be typically expected for the activity
Rapid evaporation of the chemical, and
The effect of an industrial hygiene program.
For substances which are corrosive, handled as hot liquids, or
not available for contact due to physical form (e.g.,
encapsulated within a matrix), dermal exposure is assumed to be
negligible and is not quantified..
The focus of this document is to identify pertinent data to
refine the "Q" and "S" factors and to evaluate the overall CEB
approach in estimating dermal exposure.
TABLE 1-1. TYPICAL FACTORS FOR ESTIMATING
DERMAL POTENTIAL DOSE RATE
Activity
Typical examples
S, ca* 0, ag/ca2 Resulting typical
contact, ng.
Rout in* insertion,
2 ha
Boutin* contact,
2 hand*
Routine contact,
1 hard
Incidental
contact,
2 hands
Incidental
contact,
1 hand
Source: CEB, 1991.
• Handling wet turface*
• Filling/during containers of
powders, flakes granules
• Spray painting
Maintenanee/a
equipment
(I cleaning of
• Unloading filter eaka
• Changing filter
• Filing drUa with liquid
• Connecting transfer line
• Weighing
ponder/acooping/aixIng
(I.e., dye neighing)
• Sailing
• Lading liquid/bench scale liquid
tranafer
1300 5-K
1300 1-3 *
650 1-3
6500 to 18200
1300 to 3900
650 1-3 650 to 1950
1300 1-3 1300 to 3900
650 to 1950
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OCCUPATIONAL OERMAl EXPOSURE ASSESSMENT - A REVIEW
September 30, ',994
TABLE 1-2 SURFACE RETENTION RATES
OF SELECTED LIQUIDS ON THE HANDS UNDER
VARIOUS EXPERIMENTAL CONDITIONS
Mineral oil
(mg/cn2)
Cooking oi I
Crng/cn2)
Sath oil
(mg/an*)
Initial nice
Initial film thickness of liquid on hands
1-36
2.07
1.49
Film thickness after partial wipe
0.54
0.75
0.51
Film thickness after full wipe
0.24
0.22
0.17
Secondary nioe
Initial film thickness of liquids on hands
1.22
1.72
1.34
Film thickness after partial wipe
0.41
0.48
0.41
Film thickness after full wipe
0.05
0.06
0.07
Immersion
Estimated Initial fila thickness of llqui^on
hand
10.33
6.02
S.94
Estimated ft In thickness of liquid rsaaining
afttr partial uipa
1.73
1.33
1.34
Handling « rw
Initial fila thickness of liquid on pel*
1.43
1.38
1.76
Film thickness sfter partial ulp*
0.38
0.31
0.46
Fill* thickness after full vtp*
0.11
o.ot
0.18
Soil I cleanuo
Estimated Initial ftl* thicknesa of liquid on
hand
1.07
0.67
0.77
Estimated ftl* thickness of liquid reaHining
after partial wipe
0.48
0.47
0.41
Source: Table 4-1, EPA, 1992c or Tabla 4«t, EM, 1999b for data under Initial Mipe,. secondary wipe, and
immersion. Other data froai Table 26, EM, 1967b.
Mate: Surface retention rate* not reported for handling ¦ raj and for spill clear**) in EPA 1987b. Values
in table are calculated using respective liquid density -feetor* m: Mineral oil, 0.87; cooking oil, 0.92;
and bath oil, 0.861.
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occbPAr:cn^l jesnai exposure assessment • a review
C. technical APPROACH
September 30, 1996
There are three variables in the CEB dermal exposure
equation: surface area of contact (S), quantity remaining on
skin (Q), and the concentration of chemical (C). The
concentration may be known or given or is estimated based on
available information. Specific values for Q and S for certain
work activities have been defined by CEB. The main focus of this
document is to evaluate and revise tr„-»se values and to develop
additional values through the analysis of reported monitoring
data.
The key data needed for this document are those that provide
dermal exposure data equivalent to "Q," in terms of mg/cm2 or
some other easily convertible units, and "S" in cm2. Two data
sources were used to gather the needed information:
• Dermal exposure data from published reports
• Dermal exposure data contained in the Pesticide
Handlers Exposure Database (PHED, 1992)
A literature search was conducted to identify published
reports for review and analysis of monitoring methods and data.
Then, pertinent dermal exposure data were extracted from PHED.
The exposure data were collated under various work activities for
use in evaluating the CEB method input parameters. A brief
overview of the literature search and data analysis procedures is
provided below.
Literature Search
A search of literature through the DIALOG system was
conducted to identify reports and papers that may contain dermal
exposure data. The DIALOG data files searched included:
• Chemical Safety Newsbase
• Chemsearch
• Enviroline
• Environmental Bibliography
• Pharmaceutical News Index
• NTIS
• Compendex Plus
• Chem Engineering and Biotech Abstracts
• Medline
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occupy;:nai des.mai exposure assessment • a review
Septemoer 30, '.996
• Toxline
e Occupational Safety and Health (NIOSH)
• FSTA
• Agrochemicals Handbook
• International Pharmaceutical Abstracts
• Biosis
• EMBASE
© Life Sciences Collection
• Federal Register
• Nursing and Allied Health
• RTECS
• CA Search
• CRIS USDA
® .SPIN
The literature search was conducted in several steps.
Initially all- titles in the DIALOG system whose abstracts
contained the selected key wordr or phrases were identified.
Only those reports or papers not already available from the EPA
were ordered. Each paper was reviewed to extract pertinent
information for analysis of dermal exposure data, work activity,
and work practices. Available data under similar work conditions
during mixing, loading, bagging, and other similar operations
were grouped together and analyzed to establish the exposure
range and to estimate the high end exposure. Data relating to
barrier effectiveness of the protective clothing were also
reviewed.
The DIALOG search was conducted in two phases. in trie first
phase, which was completed in 1992, the following keywords were
used:
dermal or skin exposure and qhemjca; or dy,gt;; and
dermal or skin exposure and PCB or hazardous chemicals.
Over 1800 titles in the DIALOG system were identified during
this search. The .Occupational Safety and Health file and the
Toxline file contained the most titles, each with over 700, the
EMBASE file with 106 titles had the next highest number. A
listing of those titles published since 1980 was then obtained.
Abstracts for those titles that suggest the inclusion of human
dermal exposure data were retrieved. The abstracts were then
reviewed to identify appropriate papers for acquisition.
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OCCUPATIONAL OERNAl EXPOSURE ASSESSMENT - A REVIEW
Septemc*r 30, 1994
A follow-up literature search on the DIALOG system was made
in September 1994 following the completion of a peer review with
a broader search strategy to include the use of the following key
words:
dermal or skin with exposure or contamination or wipe or
wash and chemical or dust or liquid, or vapor, or pesticide
This search identified more title's than the search conducted in
1992. Approximately 2580 titles were identified on the
Occupational Safety and Health and the Toxline files, of which
634 titles were published before 1980 and 1949 titles were
published after 1980. From this, additional papers were obtained
and reviewed.
In addition to the automated electronic database search, a
manual search of relevant secondary papers cited in the documents
already obtained was conducted. Reference papers recommended by
many peer reviewers of a draft copy of this document were also
obtained and reviewed for inclusion into the-report'.
Data on biological monitoring have been used to assess the
risk of dermal exposure or dermal absorption. However, it is
difficult to characterize biological monitoring results in terms
of relative contribution from inhalation, ingestion, and dermal
absorption (Klingner and McCorkle, 1993; Groth, 1992). Using
biological monitoring to assess dermal exposure is not the
subject of this document and reports related to biological
monitoring were not.searched or reviewed.
Aside from published reports, OSHA and NIOSH representatives
were contacted to inquire whether they have conducted any dermal
exposure studies. Both OSHA and NIOSH have expressed an interest
in dermal exposure research and assessment technology.. OSHA has
designated a surface wipe sampling technique for use by its
Compliance Safety and Health Officers (OSHA, 1990; OSHA, 1995).
However, the technique is designed primarily to evaluate
contamination on equipment or tool surfaces. OSHA has
participated-in a study to.evaluate dermal exposure to acrylamide
during grouting operations (Cummins et al., 1992). NIOSH
reported chat they had not conducted dermal exposure studies
similar to the Versar (1984) study, but numerous Health Hazard
Evaluation* (for example, NIOSH, 1982; NIOSH, 1983a; NIOSH,
1983b; NIOSH, 1984; NIOSH, 1985; and NIOSH, 1991) have been
conducted to evaluate the potential for dermal exposure (or the
effectiveness of controls) via surface wipes, luminoscope
readings on worker's skin, vacuum sampling, etc. One study
evaluated dermal exposure using cotton gauze pads_ (NIOSH, 1991).
Many of these studies included biological monitoring. NIOSH may
someday develop a Criteria Document on dermal exposure.
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che active ingredient in this mixture was analyzed by
investigators to assess the exposure hazard. Thus, the reported
exposure data represents the quantity of active ingredient, not
the amount of chemical mixture, remaining on the skin after a
certain period of exposure. Because.the focus of this document
is to determine "Q", the total mass of chemical retained on the
skin for generic uses, as opposed to the active ingredient (a
percentage of the total mass) of specific interest, all reported
pesticide exposure data were divided by' the fractional weight
concentration, "C", to back calculate the estimated total mass
retained defined herein as estimated gross dermal deposition:
Estimated Gross Dermal Deposition in Term9 of AI
Dermal Deposition = Fractional Concentration of AI in
Formulated or Mixed Product
Prior to the standardization of the pesticide testing
protocol by EPA in its Pesticide Assessment Guidelines,
Subdivision U, Application Exposure Monitoring (EPA, 1987a), the
surface area "S", used for each anatomical section of the body
varied depending on the investigators. Thus, the "S"" value for a
given section of the body is not consistent in the studies
reviewed. This presents a problem in interpreting unit area
exposure when only, the-exposure in a body section or several body
regions is reported. An appropriate "S" value is needed to back-
calculate the unit area exposure. To define."S", the data used
or recommended in various EPA reports were reviewed. Body
surface area measurements used by various investigators were
summarized for comparison with the EPA recommended values. . Based
on this comparison, the EPA recommended skin surface areas (EPA,
1987a) were used to estimate unit area deposition from the total
dermal deposition over one or several sections of the body.
The exposure data were collected, categorized, and
transformed to present estimated gross dermal deposition data in
units of ^g/cma. With a uniform measurement unit, the values can
then be compared with those reported in published reports,
contained in the PHED, and used in the CEB method.
D. REPORT ORGANIZATION
This report is organized into nine chapters:
• Chapter I, an'introduction is presented to identify the
objectives, background, and teqhnical approach of this
document.
• Chapter II, a brief review of dermal exposure
assessment methods is presented.
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:c:jpa::;mal :ermal expcslre assessment - a review
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e Chapter III, the skin surface area data are reviewed.
• Chapter IV, dermal deposition data as obtained from
published reports are categorized into various
operation or work activities for evaluation.
• Chapter V, dermal exposure data in the Mixer/Loader
file of the PHED are extracted and analyzed in this
section, an overview of the PHED is provided and data
processing procedures are described.
• Chapter VI, dermal deposition data developed in
Sections IV and V are collated in this section and
compared with corresponding input parameters for the
CEB method.
• Chapter VII, available data on barrier effects of.
various types of clothing are presented to evaluate
whether the current estimating method cam,be modified
to reflect the barrier effects.
• Chapter VIII, conclusions and recommendations for
improving the CEB methods and for future research are
presented.
• Chapter IX, References.
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OCCUPATIONAL 3ERHAI EXPOSURE ASSESSMENT • A REVIEW SfiDCSflC«r 30, '¦<}<;&
II. DERMAL EXPOSURE ASSESSMENT METHODS
A historical perspective and a general review of the
techniques of estimating dermal exposure to pesticides have been
provided in EPA's Pesticide Assessment Guidelines (EPA, L987a).
More recently, additional reviews of sampling techniques for
estimating dermal exposure have been presented by NIOSH (1991),
McArthur (1992), Van Hemmen (1992), Fenske (1993), and Ness
(1994). Based on these reviews and following F*enske's
terminology (1993), dermal exposure sampling techniques can be
classified as:
® Surrogate skin
® Removal
a Fluorescent tracer
• Surface sampling.
An overview of the commonly used methods under each of these
techniques is presented in this chapter. Additional details can
be found in the references cited above. In addition to actual
measurements of the amount of contaminants retained on skin
surfaces, various modeling parameters have been proposed by EPA.
A review of such estimating techniques is also provided in this
chapter.
A. DERMAL EXPOSURE MONITORING METHODS
Dermal exposure (the•amount of chemical contacted by the
skin and available for absorption) can be estimated by directly
sampling and measuring the amount of chemicals deposited or
retained on the skin.- Additionally, the potential for dermal
exposure can be estimated by indirectly sampling the chemicals on
the surfaces that the skin may come in contact with. This
section describes the methods available for such sampling and
discusses the advantages and disadvantages of each method.
1. Surrogate Skin Techniques
The surrogate skin techniques involve the use of a sampling
medium attached to the skin or clothing. The sampling medium may
be in the form of pads or patches, coveralls, special clothing,
and.gloves. The absorbent patch or pad method described by
Durham and Wolfe (19S2) is the most frequently used. This method
was originally developed to evaluate skin exposure to pesticide
and has since become recognized as the standard method for
pesticide exposure assessment (EPA, 1987a) .• With this technique,
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garment:, along with the patches on the garment as standard
protocol. The use of clothing as a sample collection medium
provides a more thorough representation of the exposure in the
body regions being monitored. In fact, pesticide exposure
assessment experts currently consider "whole body" (i.e., whole
garment) exposure assessment methods superior to pad sampling
(Chester, 1993). However, properly removing the garments without
contaminating them remains to be a challenging problem. Chemical
extraction from the garment requires large volumes of solvents
which may cause problems in terms of analytical sensitivity.
Each monitoring device (pads, gloves, garments, etc.,) has
its own merits and shortcomings in sample collection?- extraction,
and data interpretation. Ideally the pads should have
adsorption, absorption, and desorption characteristics similar to
the skin. Overabsorption by the pads {working as a sponge)
compared to the skin is one of the main potential biases in the
method. This problem may be of particular concern when gloves
are used to estimate hand-exposure. In an extensive review of
agricultural pesticide exposure databases, Van Hemman (1992)
could not find studies.that estimated the correlation between the
hand exposure and the deposit on gloves. Fenske (1993) stated
that the accuracy of glove and other garment samples remains an
open question.
The pad method is generally used for sampling of non-
volatile contaminants or those with a very low vapor pressure.
To sample for volatile compounds, charcoal impregnated, cloth has
been used as the sampling pad. Popendorf et al. (1983) used such
a pad to measure hand exposure to 1,3-dichloropropene during a
nematicide application. The treated cloth measured ambient air
concentrations as well as direct contact. Cohen and Popendorf
(1989) studied the use of a charcoal cloth for sampling volatile
liquid on clothing or skin. The charcoal cloth is a 100V
charcoal fabric that reportedly has good retention properties to
various solvents and vapors. . The authors found that evaporation
from liquid deposits was inversely proportional to the
logarithmic value of the droplet size, vapor pressure, and air
humidity; and that the adsorption of vapor was proportional to
the vapor concentration. The study concluded that the charcoal
cloth's accuracy and precision are optimal for monitoring dermal
exposure to materials with low to moderate volatility or with low
vapor concentration. However, no actual field measurements of
exposure were provided.
Another interest in the estimation of dermal exposure is how
much of the material collected on the pads outside the clothing
would have eventually penetrated the clothing. Thus, pads have
been placed inside the clothing to determine actual exposure and
to study pesticide penetration and permeation through the cloth.
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OCCUPATIONAL DESMAL exposure assessment • a REVIEW
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Pads have also been constructed with 'the sample of test fabric
backed up by an absorbent pad to provide a rough estimate of the
amount of residue that penetrated through the fabric.
¦2 . Removal Techniques
Chemicals can' be dissolved in solvents and thus it is
possible to remove the chemicals from the skin by washing,
wiping, or swabbing to estimate the amount deposited. Water-
surfactant mixes or water-alcohol wash solutions are generally
used to assess hand exposure in pesticide applications (Fenske,
1993). Accurate measurement of hand exposure is critical in
estimating over-all dermal exposure. According to the reviews
presented in the EPA Pesticide Assessment Guidelines (EPA,
1987a), 25 to 98 percent of total potential exposure may be from
hand exposure.
The EPA Guidelines (EPA, l?87a) suggested a standardized
hand rinse procedure for estimating hand exposure to pesticide.
With this method, each hand is placed in a plastic bag.containing
200 ml of a washing solution. The bag is held tightly just below
the wrist bone and the hand is shaken vigorously. However,
washing techniques can at best remove the chemicals that have not
yet been absorbed by or lost from the skin; removal efficiency
can vary with residence time of a chemical on the skin. The type
of solvent used will also affect the removal efficiency. Fenske
and Lu (1994) found that removal efficiency of the hand rinse
varies with chemical loading at the skin, the time between
exposure and washing, and the washing solvent. For example,
ethanol removed' 30% of the chlorpyrifos applied to the hands at
loadings of approximately 7 /xg/cnr with residence time showing no
effect. A 10% isopropanol/distilled water solution removed 43*
immediately after exposure. Swabbing or wiping is highly
operator-dependent, variability in removal efficiency is likely
to be even greater.
3. Fluorescent Tracer' and Other Light Sensing'Techniques
Fluorescent.tracers have been used as another method to
identify contaminated areas on the skin or cloth and to quantify'
dermal exposure. Franklin et al. (1981) ad4ed a fluorescent
whitening agent to azinphosmethyl in a pesticide spray mixture.
After removing exposed pads and clothing, each pesticide
applicator was examined with ultraviolet light. The tracer was
found in areas such as the face and neck which were not monitored
with pads. The tracers were also found underneath the clothing.
Fenske et al. (1985, 1986a, 1986b) combined the use of
fluorescent compounds and video imaging measurements to produce
exposure estimates over virtually the entire body. The
investigators used the pre- and post-exposure images, standard
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OCCUPA 7: :wal ;E3.«ML EX?OSuRE asshssment ¦ A REVIEW
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curve relating dermal fluorescence to skin-deposited tracer, and
chemical residue sampling to estimate the quantity of chemical
deposited on the skin.
The use of tracer technique has several important
limitations. As discussed by Fenske (1993), the limitations can
include: _ potential interference with the intended usage and
performance of the chemical; different rates of transfer between
the tracer and the chemical to the skin; potential degradation of
the tracer during field use; and varying penetration
characteristics between the tracer and the chemical through
clothing.
Analogous to the fluorescent tracer technique, some
investigators have used visible spectrum detection to estimate
dermal exposure. Hill (1984) described a method utilizing the UV
excitation principle to quantify surface or skin fluorescence
from contamination. Two developmental instruments, called the
Spill Spotter and the Lightpipe Luminoscope developed earlier
(Schuresko, 1980; Vo-Dinh and Gammage,. 1981) were used in this
study. Both instruments produce a beam of low-intensity,
longwave UV light to cause emission in the visible range from
excited polynuclear aromatic compounds. The emissions were then
measured by the instruments which quantify the fluorescence as
voltage response. By calibrating the' fluorescence against a
known area concentration of polynuclear aromatic compounds in a
heavy distillate on pigskin, it was possible to estimate the
heavy distillate equivalent of skin contamination.
Lengerich and Burroughs (1989) tested a near real-time
monitoring procedure for estimating potential dermal exposure
during backpack herbicide spraying. In this test, water-
sensitive paper strips, which stain blue upon contact with spray
droplets, were attached uniformly to the applicator on six
regions of the body. After field exposure, the density of stain
spots on paper strips was compared to standard strips sprayed
with known droplet density. This method provides an almost real-
time assessment of potential dermal exposure to various parts of
the body, but not the actual exposure.
4 . Surface Sampling Techniques
Dermal exposure, especially of the hands, can occur through
contact with contaminated surfaces, tools, and equipment.
Surface sampling is a logical approach to assess such exposure
hazards. OSHA's Technical Manual includes a surface
contamination sampling technique for use by its Compliance Safety
and Health Officers (OSHA, 1990;. OSHA, 1995). It is" designed to
evaluate potential contact of skin with contaminated surfaces, to
determine surface contamination that may come into contact with
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OCCUPATIONAL 3EW»l EXPOSURE ASSESSMENT • A REVIEW
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food or other materials that are ingested, and to assess the
effectiveness of personal protective equipment. Based on the
reports of several investigators using the OSHA or modified OSHA
procedure, Fenske .(1993) indicates that there is a need to
develop a surface sampling technique which employs standard
materials and procedures, samples a defined surface area, and is
operator independent. The author further states that the goal
should be to collect "transferable" residues, not 100% of- surface
residue, to be able to accurately assess the potential transfer
of surface residue to the contacted skin and that a Dermal
Transfer Coefficient may be estimated for specific work
activities.
Technically, it is possible to use the OSHA surface sampling
technique to sample for the chemical deposited on the skin.
However, the OSHA technical manual contains numerous
recommendations against the use of skin wipes. The manual states
that "direct skin wipes should not be taken when high skin
absorption of a substance is expected. Under no conditions
should any solvent other than distilled water be used.on skin,
..." (OSHA, 1995). Additionally, special considerations are
included in the OSHA'technical manual regarding skin wipe
samples. It states: "Do not take surface wipe samples on skin
if a) OSHA or American Conference of Governmental Industrial
Hygienists (ACGIH) exposure limit shows a "skin" notation, the
substance has a skin LD5Q of 200 mg/kg or less, or an acute oral
LD50 of 500 mg/kg or less, b) the substance is an irritant,
causes dermatitis, contact sensitization, or is termed
corrosive." Aside from these potential problems, the process of
collecting wipe samples can be very subjective (e.g., exerted
force) which introduces additional biases. Also, removal
efficiency of the wipe procedure is unknown.
B. DERMAL EXPOSURE ESTIMATING METHODS
In addition to the equation for estimating dermal exposure
used by CEB, the OPPT Exposure Assessment Branch (EAB) and the
EPA Office of Research and Development (ORD) have developed other
estimating methods. The EAB method and certain aspects of the
ORD method follow the same basic approach, in which the total
exposure ij calculated by extending the estimated exposure based
on deposition at unit areas over the entire exposed skin area.
Because each method was developed to address a specific need, the
input parameters are somewhat different. The following is a
review of the EAB and the ORD methods.
1. EAB Method.
The EAB assesses exposure to chemicals that results from
contact with consumer products. The' computer program, DERMAL,
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OCCUPATIONAL OERHAL EXPOSURE ASSESSMENT - A REVIEW
September 30, 1996
developed by the EAB is to be used in performing screening level
estimates of Potential Dose Rates (PDRs) from dermal contact with
consumer products (EPA, 1995; EPA, 1987b). The potential dermal
dose rate is defined as the amount of chemical contained in the
material applied to or contacting the skin (EPA, 1992b). The
PDRs resulting from contact with the following list of consume'r
products are assessed by DERMAL:
1.
General Purpose Cleaner - full strength and dilute
2 .
Liquid Laundry Detergent/Fabric Softener
3 .
Rug and Upholstery Cleaner
4 .
Floor Cleaner
5 .
Bar soap
6.
Vinyl Upholstery Cleaner
7 .
Wax strippers
8'.
Spray Paint - undiluted
9 .
Exterior Latex Paint
10.
Interior Latex Paint
11.
Oil-based Paint
12 .
News Ink (
13 .
Used Motor Oil
14.
Lubricating Greases
15.
Diesel Fuel
16 .
Gasoline
Assessors can also estimate PDRs from other products by using the
"generic products" scenario in DERMAL. Users of the program can
input product-specific data (e.g.,' weight fraction of chemical,
density of formulation, frequency of events, etc.) for a
particular scenario if relevant information i9 available.
Dermal exposure to the 16 products listed above can be
categorized as occurring by one of the following pathways:
1. Deposition of a film of liquid on the skin
Product Example: Used Motor Oil
2. Contact with solid surfaces
Product Example: News Ink.
PDRs resulting from dermal exposure are calculated by the
following equations:
PDR » WF X AV X T X DSY X FQ x DIL X 1000" mg/g (1)
PDR = WF x MASS x FQ (2)
where
PDR = potential dose rate (mg/yr)
WF = weight fraction of chemical substance in product
(unitless)
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3c;'_pat::nal :e*.mai exposure assessment • a review
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AV = skin surface area exposed per event (cm2/event)
T = film thickness of liquid on the skin surface (cm)
DSY = density of formulation (g/cm3)
FQ = frequency of events per year (events/yr).
DIL = dilution fraction (unitless)
MASS = mass of formulation
Equation (1) is used for all of the products in DERMAL except for
news ink. A slightly altered form of equation (l) is used for
bar soap because exposure to chemicals in soap can occur from
washing hands as well as taking baths/showers. The number of
events per year and the surface area exposed are different for
these two events. Equation (2) is used for news ink. The
calculation differs because news ink is a solid substance rather
than a film of liquid deposited on the skin.
Default values which can be changed by the assessor, are
currently used for all of these variables. The weight fraction
.of the chemical in the product is normally chosen from a list of
defaults based on information from the submitter-regarding the_
function (and sometimes the formulation percent) of the chemical
in the product. The default values currently in DERMAL come from
Standard Scenarios for Estimating Exposure to Chemical Substances
During Use of .Consumer Products (Versar, 1986) and from exposure
scenarios developed by the EAB.
In accordance with EPA's Guidelines for Exposure Assessment
(EPA, 1992a), the EAB will also calculate Lifetime Average Daily
Doses (LADDs) in terms of mg/kg/day. The same equations for PDRs
will be used, with appropriate default values for FQ, in
calculating, the LADDs-. PDRs for both acute and chronic exposures
will be calculated. Specific parameters in defining the input
values for these calculations have been suggested by the EAB.
The EAB currently characterizes' their consumer.dermal exposure
estimates as hypothetical "what-if" estimates because of the
numerous uncertainties associated with estimating the dermal PDR.
These uncertainties (particularly concerning skin surface area
and number of thin films contacts) prelude determining where the
estimates lie on the actual distribution of exposures.
The film thickness of a liquid on the skin (T) is the
quotient obtained by dividing the mass of liquid retained per
square centimeter (cm2) of skin surface by the density of the
liquid as used by the consumer. Table 2-1 presents values for
film thickness rate of selected liquids under various
experimental conditions based on data presented ir. EPA,'1992c,
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cc-jpa';cnal :e?mai exposure assessment • a review
September 30, '.?96
TABLE 2-1 FILM THICKNESS VALUES
OF SELECTED LIQUIDS ON THE HANDS UNDER
VARIOUS EXPERIMENTAL CONDITIONS
Hinersl oil
Ct/TD)
Cooking oil
(IM>
Bath at I
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OCCUPATIONAL 3ERHAL EXPOSURE ASSESSMENT • A REVIEW
September 30, 199,5
and EPA, 1989b. Jorresponding data expressed as skin surface
retention rates in mg/cm2 are already presented in Table 1-2.
These data were originally developed and reported in Exposure
Assessment for Retention of Chemical Liquids on Hands (Versar,
1984). In addition for use in the above equations, the surface
retention rates as found from this study form the basis for the
input parameters used in the CEB method.
In the Versar study, selected liquids were applied to the
hands of test subjects and then removed. The amount of liquid
initially applied and the amount retained after wiping were
determined. Originally, 3 aqueous and 3 non-aqueous liquids were
used. However, due to the difficulties of accounting for
volatilization and evaporation losses, only the data from non-
aqueous liquids (mineral oil, cooking oil, and bath oil) were
retained. In the study, the liquid was applied to the hands from
a saturated cloth. The amount of liquid initially retained on
the hands was determined by the_difference between the before and
after application weights of the cloth (and holding-cup).
Separate dry removal cloths were then used to wipe hands both
partially and fully. The difference between the amount of liquid
initially retained on the skin and the removal cloth was
determined as the amount remaining on the hands after wipe
removal. An "initial wipe" was performed with the hands washed
first before application of the liquid, while the "secondary
wipe" was performed immediately after the completion of the
initial wipe testa without intervening washing of hands. The
immersion tests were performed by dipping subjects' hands (after
thorough washing) into a container holding the liquid and then
wiping partially and then fully with separate dry cloths. In the
test of handling a rag, the test subject handles saturated rag
and the amount' retained on the hands was determir from the
partial and full wipes. For testing liquid retention from
cleanup, test subjects cleaned up 50 ml of spilled liquid with a
dry clean rag and the amount removed from partial and full wipes
were determined.
To assess dermal exposure to liquids that are not listed in
this table, one can use the data for the liquid that most closely
resembles the liquid for which one is trying to assess exposure.
Two physical properties that can be used to compare liquids for
the purpose of assessing dermal exposure are kinematic viscosity
and density. As a comparison, the maximum loading on the skin
can be interpreted as approximately 10 mg/cma based on the
immersion test with mineral oil (see Table 1-2). In a study by
Rutledge (1988), the maximum retention or the limit of ^
aDplication of an insect repellent was reported to be 4 mg/cm
before runoff will start. This value is very close to the values
in Table 2-1, considering the difference in viscosity and
density. It should be noted that the data in Tables 1-2 and 2-1
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should be applied only for estimating liquid retention on the
skin. Retention of solids on the skin was not tested in the
Versar Study (1984) and estimation of solid retention should rely
on" other more relevant data as presented in this document.
2. ORD Method
The ORD method was developed to estimate absorbed dose
through dermal contact with contaminated water and soil (EPA,
1992b). Due to the nature of dermal absorption processes,
different approaches are used for assessing absorption of
chemicals which are liquids versus solid or particulate
materials. For solid media such as dust, the assumption is that
the process o£ absorption into the skin is sufficiently slow that
one can separate the deposition from the absorption process.
However, for liquid media, there could be overlapping between tne
deposition and absorption because of the potential rapid
absorption. Both processes must- be considered together as a
continuous process in assessing dermal exposure hazard. The
permeability coefficient approach advocated by ORD for liquids
represents an attempt to address these considerations.
With the ORD approach, a permeation coefficient (Kp) that
represents the rate at which the chemical penetrates the skin
(cm/hr) is used to estimate absorbed dose per event from contact
with aqueous solutions. For contact with particulate matter such
as contaminated soil, an absorbed percent is used to estimate the
fraction of the applied dose or the estimated amount adhered to
the skin being absorbed across the skin in a specified time.
ORD's method in estimating dermal absorption from exposure
to an aqueous solution is based on a theoretical analysis of. the
physical processes and mathematics involved. To account for the
reservoir effect of the skin when in contact with organics, the
skin is divided into two layers: the stratum coraeum and the
epidermis. A differential equation was formulated to describe
the movement of the chemical in liquid media through each layer
as a function of,time and penetration flu*. By defining the
initial and boundary conditions for these equations, the
equations were solved to estimate the absorption rate. The
system of partial differential equations requires knowledge of
the initial conditions of exposure (i.e., at time 0, what is the
concentration of contaminant on each layer of the skin?) , and the
boundary conditions (i.e., what is the concentration of the
chemical on the surface of each layer at the end of the exposure
period?). It is important to note that the ORD approach was
developed for scenarios such as*swimming or bathing where an
"infinite" exposure or-boundary layer exists. -Thus, the system
of partial differential equations would need to be modified to
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OCC'JPAT [CNAl 2ESHAL EXPOSURE ASSESSMENT • A SEVIEW
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reflect the appropriate boundary conditions for occupational
exposure, which would generally be "finite" in comparison.
Based on a steady-state flux, absorption of an inorganic
chemical in water through the skin is estimated as:
^^event = ^ event
where:
DAavenE 3 Dose absorbed per unit area per event (mg/cm2 -
event)
Kpw = Permeability coefficient from water.(cm/hr)
C„ = Concentration of chemical in water (mg/cm3)
cav«nt = Duration of event (hr/year)
A default value of 10'1 cm/hr for Kp" for inorganics is
recommended.
For organics in an aqueous matrix, absorption under
unsteady-state must be accounted for, and mathematical formulas
for estimation of absorbed dose can be found in Chapter 4 of EPA,
1992b.
Experimentally measured Kp values for about 70 chemicals of
potential environmental interest in an aqueous solution are
available (See Table 5-3 of EPA, 1992b). Predicted Kp values for
another 200 chemicals in aqueous solutions are also available
(Table 5-7 in EPA) 1992b). An estimating method for other
organics not listed is provided in the document referenced (EPA,
1992b) . No information is provided on the values of Kp for
chemicals in a non-aqueous solution.
This predictive method is very new and the permeability
coefficient values will contribute the most to the uncertainty
associated with model .estimates* Permeability coefficient values
can be determined experimentally, but the result is dependent on
the experimental, conditions. This method is recommended by EPA's
ORD for inorganic liquids of infinite volume in aqueous media.
EPA recommends making a "reality check" when developing estimates
using this method.. The estimated absorbed dose, should not exceed
the amount of contaminant in the- water. The estimate should be
questioned if the estimated absorbed dose exceeds 50% of the
contaminant in water (EPA, 1992b)."
For estimating dermal absorption from contaminated soil, a
surface retention or adherence, rate is used with percent
absorption to calculate per event,dose:
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OCCUPATIONAL 3E*ML EXPOSURE ASSESSMENT - A REVIEW
September 30, 19V6
DA;vent — ^-soii x AF x ABS
where :
DA.venc = Absorbed dose per event - (mg/cm3 - event)
csoii = Contaminant concentration in. soil (mg/kg) (10"S kg/mg)
AF = Adherence factor of soil to skin (mg/cm: - event)
ABS = Absorption factor.
Life-time exposures are estimated by accounting for contact
time per event, frequency, life-time exposure duration, dose
absorbed per event, and total exposed skin surface area. The
range of recommended default values for dermal exposure factors
as recommended by ORD is presented :in Table 2-2. These default
values represent the central tendency and upper bound estimates
of each parameter. The soil adherence rates of 0.1 and 1.0
mg/cm2 are estimates of adherence over the entire potentially
exposed skin that covers several- regions -of the body. However,
Kissel et al. (1996a) reported that soil loading encountered in
realistic exposure scenarios car* extend beyond either end of this
range. The authors suggested a geometric mean hand loading of
0.01, 0.1, 1.0, and 10.0 "ttg/cm3 to characterize roughly the solid
adherence from background, low, moderate, and high contact
activities, respectively. Soil adherence to the skin is also
affected by the grain size and moisture content. Kissel et al.
(1996b) reported that for dry soil adherence varies inversely
with grain size but increases with grain size at moisture content
of 12 to 18%.
TABLE 2-2
RANGE OF RECOMMENDED DEFAULTS FOR DERMAL EXPOSURE FACTORS
Water Contact
Sail Contact
Bathing
Swfaaing
Cantral
upp
Cantral
Uepw
Cantral
Upper
Event tine
and
frequency
10 aln
/•van t
1 event/day
350 daya/yr
15 aln
/event.
1 avant/day
350 dey/yr
.0,3 hr/avent
1 avant/day
5 daya/yr
1.0 hr
/event
1 avant/day
150 daya/yr
40
eventt/yr
350
avants/yr
Exposure
. duration
9 yr
30 yaara
9 yr
30 yaara
? yr
30 yaars
Adult skin
surface
area*
20,000 e*2
23,000 eo2
20,000 enf
23,000 ca2
5000 oa2
5,WO cat2
Soi l-to-alcin
adherence
rate
0.2 ma/ea^
event
1.0 mg/aaJ-
evant
Sourca: EPA, 1992b, Tiblt 8-6.
* Sea Table S-3 of EPA, 1992b for children skin turface am.
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CCC'JPA T i 3NAL D£?MAL EXPOSURE ASSESSXEMT - A REVIEW
September 30, 19V6
3 . APPLICATION TO DERMAL ABSORPTION ASSESSMENT
For exposures to particulate or solid materials, the
critical factors in estimating dermal exposure are the adherence
rate or surface retention rate in terms of mg/cm2 and the surface
area in contact with the-contaminant. The EAB method contains
two factors, DSY and T, for liquid exposure which translates into
mg/cm2; the ORD method dust adherence factor is also expressed in
terms of mg/cm2. Using such parameters, total exposure can be
calculated for the total area of skin surface exposed either on a
daily, hourly, yearly, or per event basis. This approach is
similar to CEB's approach. In fact, the same database was used
to develop the default values in both the CEB and EAB methods.
The ORD adherence rate and the CEB surface retention
parameters will be influenced by factors such as the quantity of
material handled, the duration and frequency of exposure, and the
physical state of the material handled. The current method used
by CEB is fairly simplistic and does not fully consider these
factors.
The ultimate goal of developing a dermal exposure assessment
method is to allow estimation of the amount of chemical absorbed
through the dermal route of exposure. The current CEB method
generates an estimated potential dose retained on the skin over
the duration of one day's work. The estimated potential dermal
dose is then used with an estimated percent absorption factor to
predict absorbed dose for both the solid and liquid materials.
This approach is analogous to ORO's estimating method for.
absorption from-contaminated soil. It should be noted that the
percent absorption may be dependent on skin loading, at least for
solid materials. Duff and Kissel (1996) reported that relative
percent absorption increased significantly with decrease in soil
loading from 10 to 5 and from S to 1 mg/cm12. The authors
postulated that this inverse relationship was due to incomplete
coverage of the skin at the lower loading and multiple layer
loading at the higher loading. Loading of solids and.coverage on
the skin may be important parameters in assessing dermal
absorption of solids.
ORD uses a separate approach, the permeation coefficient
approach, to estimate dermal absorption of chemicals from water
during such activities as swimming and bathing. This_approach
was developed based on current understanding, of the biological
mechanism of dermal absorption including skin-structure,
transport processes, metabolism, and factors that affect dermal
absorption (e.g., body site, hydration level). The mechanism for
dermal absorption of chemical from a liquid matrix differs from
the dermal absorption from a solid or particulate matrix. The Kp
or skin permeation coefficient approach is recommended by ORD for
2-14
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:c:uPAr;;NAi de^hal exposure assessment - a sevieu
Sepcemcer 30, IWA
assessment of dermal exposure to liquid chemicals where
applicable, and surface deposition rate with an absorption
fraction is recommended for exposure to chemicals in solid form.
It may be possible to modify ORD's approach for use with
non-aqueous media to directly estimate absorbed dose in
occupational exposure situations. However, Kp values must be
available in order to use the ORD method. Kp values for a large
number of chemicals in aqueous solutions are available based on
experimental data. Some empirical equations have also been
developed to estimate Kp values. Information is not yet
available to estimate the value of K„ for chemicals in a non-
aqueous solution which is more often, encountered in many
occupational settings. Additionally, as pointed,out in the ORD
document (EPA, 1992b), the method represents a new and still
evolving approach and tends to give overly conservative estimates
of absorbed dose. The lack of data and associated uncertainties
may limit its applicability in the near future in assessing
dermal absorption from occupational exposures.
Much of the data needed in estimating dermal absorption have
been developed through in vitro or in vivo studies. Proposed
guidelines for.testing percutaneous absorption of .chemicals by
both the in vitro and in vivo methods have been developed by the
Organization for Economic Cooperation and Development (OECD)
Examples of other procedures that were used by various
investigators can be found in Bronaugh and Maibach (1991). and in
Wang et al. (1993) . The Interagency Testing Committee (ITC) is
in the process of reviewing the available- dermal absorption data
for approximately 600 chemicals submitted by QSHA. The ITC has
designated approximately 30 chemicals for dermal absorption rate
testing. This dermal absorption data is important not only in
determining the need for "skin.designations" under OSHA
regulations, but also in evaluating the potential impact of
dermal exposure.
2-15
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OCCUPATIONAL 0S3MAL EXPOSURE ASSESSMENT - A REVIEW
III. SKIN SURFACE AREA
September 30, 19<56
A. SKIN SURFACE AREA MEASUREMENTS
The CEB dermal exposure estimation method calculates
chemical deposition at a certain region of the body by extending
the unit area deposition over the entire region. Chapter II
describes various sampling methods and modeling techniques to
estimate unit area deposition or exposure. The other critical
factor needed to assess dermal exposure is the area of the skin
exposed. In this chapter, relevant EPA documents and other
published dermal exposure literature were reviewed to identify
the most current data on skin surface area.
. Several recent EPA documents contain reviews and
recommendations on skin surface area, including:
• Dermal Exposure Assessment: Principles and
Applications, Interim Report, January 1992 (EPA, 1992b)
® Exposure Factors Handbook, July 1989, (EPA, 1989a,
currently under revision)-
o Pesticide Assessment Guidelines, Subdivision U,
Applicator Exposure Monitoring, 1987 (EPA, 1987a)
© Methods for Assessing Exposure to Chemical Substances,
Volume 7, April 1987 (EPA, 1987b).
All of the above EPA documents present similar estimates of adult
human body skin surfaces. All reference the same data source:
EPA Report, Development of Statistical Distributions or Ranges of
Standard Factors Used in Exposure Assessments, 1985 (EPA, 1985).
A summary of these estimates is presented in Table 3-1.
A literature search for dermal exposure studies revealed
that a number of earlier studies have been frequently cited when
surface area estimates are required. These studies included
Dubois (1916), Boyd (1935), and Berkow (1931). Dubois (1916)
used a linear direct measurement technique and made estimates
based on the principle that surface area of the parts of the body
are proportional- to, rather than equal to, the surface area of
the solids they resemble. Berkow (1931) used Dubois' formula to
apportion surface areas at different parts of the body.. Boyd
(193 5) made direct measurements using body coatings,
triangulation, and surface integration. The Berkow (1931) study
is the most cited study for skin surface area. Other studies of
body surface areas have been reported by Popendorf (197S),
3-1
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OCCUPATIONAL DERMAL EXPOSURE ASSESSMENT • A REVIEW
Popendorf and Leffingwell (1982),
Burmascer (1992).
September 30, '.996
EPA (1985), and Murray and
TABLE 3-1 SURFACE AREA BY BODY PART FOR ADULTS (cm2)
Men
Women
Body Part
Mean
n
Mean
n
Head
1,180
29
1,110
54
Trunk
5, 690
29
5,420
54
Upper Extremities
3,190
48
2,760
57
Arms
2, 280
32
2,100
13
Upper Arms
1,430
6
Forearms
1,140
6
Hands
840
32
74S
12
Lower Extremities'
6,360
48
6,260
57
Legs
5, 050
32
4, 880
13
Thighs
1,980
32
2, 580
13
Lower Legs
2,070
32
1, 940
13
Feet
1,120
32
975
13
TOTAL
19,400
48
16,900
13
n = Number of observations.
Source: EPA, 1985.
The skin surface area estimates of the studies mentioned
above are made with differing methods and many are based on a
very small number, of subjects, creating some variation in the
values provided for the same body region. Variation between
studies is also due to differences in definition of the areas
that make up a particular portion of the body. One of the most
important and widest variations in surface area of a single body
part is the hands. Whole hand and finger measurements range from
808 cm2 (Berkow, 1931) to 1300 cm2 (Popendorf and Leffingwell,
1982). In addition, there may be measurement differences
relating to whether the surface areas measured include only the
3-2
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OCCUPATIONAL 3E3KAL EXPOSURE ASSESSMENT " A REVIEW
September 30, :996
nearly flat: aonfollicular areas or the three-dimensional
follicles as pointed out by Slone ( 1993 ) . Slone believed that
there is insufficient evidence that skin surface areas have ever
been measured accurately. Because dermal exposure estimates are
proportional to skin surface area, variation or error in the
surface area estimate will affect the outcome.
Based on the data reported in various dermal exposure
studies, the EPA Pesticide Assessment Guidelines (EPA, 1987a)
recommended the values as shown in Tabls 3-2' for the surface
areas for various regions of the body and locations of dermal
exposure pads that represent these regions. This set of data
matches very well with the data shown in-Table 3-1. In addition,
this document provides guidance on relating the deposition data
from exposure pads to appropriate body sections.
The recommended approach is to use the values presented in
Table 3-2 based on the EPA (1987a) guidelines. The guidelines
are based on recent data and are used in PHED. It should be
noted that the Chemical Engineering Branch method currently uses
the Popendorf and Leffingwell (1982) values to estimate surface
areas of the hands.
B. SURFACE AREA/BODY WEIGHT DISTRIBUTION DATA
As described in Chapter II, the EAB method recommends the
calculation of LADD-type values where exposure assessments will
be used to support risk assessment. The LADD equation involves a
surface area factor in the numerator and a body weight factor in
the denominator. The current OPPT default value for body weight
for risk assessment purposes is 70 kg for males and 60 kg for
females. However, the skin surface area or surface area
distribution values¦are not necessarily consistent with a 70 or
60 kg body. Thus the EAB Dermal Model suggests the use of a
surface area/body weight, ratio to replace the surface area and
body weight factors (Phillips et al., 1992)'. For instance, a 50
percentile surface area/body weight ratio for- an adult is 0.0286
m2/kg, while the 95 percentile ratio is 0.0329 m2/kg. By using
this approach, the EAB believes that a more accurate
representation of surface area and body weight could be made to
calculate dermal exposure.
3-3
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OCCUPATIONAL 3ERMAL EXPOSURE ASSESSMENT • A REVIEW
Septenear 30, I9"56
TABLE 3-2 EPA RECOMMENDED VALUES ON BODY SURFACE AREA
AND CORRESPONDING LOCATIONS OF DERMAL EXPOSURE PADS
Region of
the body
Surface area
(cm2) of region
Location of pad(s)
representing region
Head
1,300*
Shoulder, back, chestb
Face
650
Chest
Back of neck
110
Back
Front of neckc
150
Chest
Chest/stomach
3,550
Chest
Back
3,550
Back
Upper arms
2, 910
Shoulder and
forearm/upper arm
Forearms
1,210
Forearm
Hands
820
Thighs
3,820
Thigh
Lower legs
2,380
Shin
Feet
1,310
4 Surface area for-the head includes the 650 cm3, face surface
area.
b Exposure to the head may be estimated by using the mean of
the shoulder, back, and chest patches, or by using a head
patch.
c Includes "V" of the chest.
Source: EPA, 1987a.
3-4
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OCCUPATIONAL 3ERHAI EXPOSURE ASSESSMENT - A REVIEW Septwfcer 30, 1996
IV. DERMAL EXPOSURE DATA FROM PUBLISHED REPORTS
Dermal exposure data available from published reports are
almost exclusively reported as part of pesticide exposure studies
which typically include inhalation exposure as well. The extent
of exposure obviously is related to the type of operation
involved. Therefore, exposure is typically reported on the basis
of a pesticide-related operation such as mixing and loading,
application, flagging, or a combination of som£ of these
operations. -Among these operations, only the mixing and loading
operation can find comparable equivalents in an industrial
setting. For instance, raw ingredients are routinely weighed,
mixed, and loaded into a mixer, reaction vessel, or similar
equipment, during chemical manufacturing. Notwithstanding the
difference in the equipment, procedures, .and the scale of
operations, mixing and loading occur both in industrial and in
pesticide operations.
Other pesticide operations have little in common with even a
similarly termed industrial operation. For instance, the paint
spraying operation as used in industries generally involves the
use of spray paint booths with the spray jets pointed forward
while pesticide spraying is usually performed with the operator
in a tractor cab or an airplane cockpit with the spray jets
pointed upward' or downward. In the case of greenhouse pesticide
spraying, the movement of the sprayer and the direction of spray
jets also can not find comparable industrial spraying situations.
Therefore, data on pesticide spraying operations in both the
fields and greenhouses are excluded from this document. Data
related to flaggers are also excluded for the same reason.
Pesticide reentry dermal exposures also are not believed to be
comparable to industrial dermal exposures. After a designated
period of time post-application, a worker reenters an iarea where
pesticides have intentionally been applied. The worker may then
be potentially exposed to dislodgeable residues from foliage and
other surfaces which have been treated. Industrial workers may
also be potentially exposed to dislodgeable residues, but the
source of the contamination will be quite different. Therefore,
pesticide reentry exposure data-are not included for analysis.
From the literature search conducted, approximately 100
papers were identified to be related to pesticide mixing and
loading operations. A few pesticide studies with data on bagging
and stacking operations were also identified. Of the published
reports with data on mixing and loading operations, the types of
formulation and mixing-methods include mixing of dry
powder/materials, mixing of powder with a liquid, mixing of
liquids, and liquid pumping. Additionally, there are a few
papers that contain non-pesticide data, which generally report on
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OCCUPATIONAL DESML EXPOSURE ASSESSMENT • A REVIEW
September 30, '994
the exposure from intermittent contacts in industrial settings.
Based on this analysis of the available studies, the relevant
data are grouped into the following categories for discussion:
mixing of powders, bagging, stacking, mixing of powder with a
liquid, liquid mixing and transfer, and intermittent contact.
Typically, dermal exposure to pesticide was determined by
multiplying the amount of the active ingredient retained on
absorption pads attached to the skin or work clothing by the area
of the body section that the absorption pads represent. For hand
exposures, most studies analyzed hand wash solutions to determine
dermal exposure. Such data are commonly expressed in terms of
hourly exposure (mg/hr) since most: tests were conducted for a
duration of 30 to 60 minutes. Some studies chose to report the
exposure on a daily exposure basis (mg/day) by extending the
measured level to an assumed daily exposure duration. Such a
time normalized approach is particularly evident in those papers
published before the early 1980 "-s. Later papers often reported
dermal exposures in terms of the quantity of chemical or quantity
of active ingredient handled (mg/lb.AI).
With the CEB method, the potential dermal dose is estimated
on the basis of daily exposure (mg/day) and assuming one or two
dermal exposure events per day. It does not imply an estimate of
8 continuous hours of exposure. The implication is that the
calculated dermal dose represents a daily retention of
contaminants on the skin either through a single contact event or
multiple events.
Retention of chemicals on the skin surface does not
necessarily follow a linear relationship with exposure duration
or the quantity of chemical handled. There is a limit.to the
amount of chemical that can-be retained. A single exposure event
may be sufficient to reach the maximum retention, for instance,
immersion.' Therefore, using an hourly retention rate (e.g., in
mg/cma/hr or mg/hr) to characterize dermal exposure could be
misleading as reported by Kilgore et al. (1984) and Knarr et al.
(1985) . Normalizing, exposure on the basis of total quantity of
active ingredients (e.g., in ^g/cma/lb. Al) handled was found to
be more appropriate to evaluate'pesticide exposure (Franklin et
al., 1981). However, linear extrapolation of exposure by the
quantity handled can also lead to overestimation. For this
document, available data are normalized by both time and
quantity, where applicable. This way the data can be
extrapolated by either factor, whichever is applicable or more
appropriate.
As described in Section II, dermal exposure data in
pesticide studies are reported only for exposure to the active
ingredient. For this report, the total amount of chemical
4-2
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occjP4r;cnal ;e?mal exposure assessment • a review
September 30, 1994
deposited on the skin, not the active ingredient, is of primary
interest. Therefore, a term "Gross Dermal Deposition" is
designated to represent the estimated total mass of the chemical
product deposited on the skin. It is calculated by dividing the
reported exposure by the fractional weight concentration of
active ingredient in the chemical. This does not mean the inert
material and the diluent in the pesticide mixture are of concern
in exposure, rather, it is the numerical value of the "total
amount" that is of interest in this document for generic
applications.
For example, if a 25* Nitrofen powder is handled, the
reported exposure of 10 jig/cm2 to the active ingredient on the
skin would mean that an estimated 40 ^g/cmJ (10- divided by 0.25)
of the formulated powder product has been deposited on the skin.
If the same Nitrofen powder is mixed to make a spray solution
with a concentration of 0.5%, a dermal exposure of 10 ng/cm2
implies that an estimated 2000 /*g/cma (10 divided by 0.005) of
the spray mixture was retained on the skin. Most of the
pesticide studies provide- information on formulation
concentration and dilution factors; therefore the reported dennal
exposure can be converted into deposition. However, it should be
noted that this approach of Calculating the estimated gross
deposition from a given amount of active ingredient is rather
simplistic and assumes that all ingredients in a pesticide
mixture behave the same physically. Different ingredients may
have different, deposition, evaporation, or absorption rates.
Many different forms of data presentations are found in the
available reports. Exposure may be presented in detail with
individual data points and certain statistical descriptors; as a
range; and as arithmetic or geometric means with or without
standard deviations. The data may have been normalized by time
or quantity with or without the duration or quantity of chemical
reported. Additionally, some investigators only report the total
exposure at a body section or at several body sections combined
(e.g., mg/hr at forearms), while others report exposure in unit
area loading rate, i.e., the data from absorption pad. To be
able to combine and compare the data from various reports, a
uniform unit must be used. Thus, for this document, the reported
dermal exposure data are converted to estimated gross dermal
deposition first then.normalized by time to obtain a unit as
^ig/cmVhr and normalized by quantity of the formulated product to
obtain a unit of ^g/cma/gal or ^g/cmJ/lb, where applicable.
In the remainder of this chapter, dermal exposure data are
grouped by specific formulation type and operation for
discussion. Furthermore, operational factors such'as indoor or
outdoor operation, manual transfer or mechanical pumping, open or
closed mixing, and use of protective clothing are identified and
4-3
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3ccjpa::;nal :esmai exposure assessment • a review
Sepcemc«r 30, 1996
the underlying data categorized and treated accordingly. For
instance, most of the mixing and load-ing operations found in
published reports are performed outdoors, the few data points for
indoor mixing were presented but excluded from further
statistical analysis. Other factors that may affect dermal
exposure such as sampling and analysis method, study protocol,
work practices (use of protective clothing), and any unplanned
worker actions are usually reported in the papers cited in this
document. All these factors were evaluated to ensure that the
data can be properly interpreted and compared with other studies.
For instance, most of the studies use a hand rinse procedure to
determine hand exposure. Dubelman et al. (1982), Everhart and
Holt (1982), Nigg and Stamper (1983), and Wojeck et al. (1983)
used glove extract to determine hand exposure which may result in
overestimates. Their hand exposure data are included in the data
tables presented in this chapter but are not included for
distributional analysis. For exposure at other parts of the
body, absorption pads .are used in all studies cited except the
study by Chester et al. (1387) who used the entire corresponding
sections of Tyvek suits as samplers. Their data are well within
the range reported by other investigators and are included for
analysis.
A data table summarizing the data, including the reported
exposure and the normalized gross dermal deposition data, is
prepared for each operation. In each data table, chemical
product name and Al concentration-, is provided in the first
column. This is followed by specific body sections for which
exposure data are available. The reported average exposure
and/or range of exposure in mg/hr or /ig/cm2 depending on the unit
used by the original.investigators, is then provided for the body
section cited.- Exposure duration in hours and quantity of
chemicals handled in pounds or gallons then follow. In the next
column, the estimated gross dermal deposition in ng/cm2 for the
body section cited is presented. Where necessary, applicable
skin surface areas from an EPA report (EPA," 1987a) are used to
convert the data to a unit area gross deposition. If only the
hourly exposure rate is reported in the paper the gross dermal
deposition is calculated on the basis of the reported duration of
exposure, or an assumed exposure period is used. Data in the
last two columns are calculated by dividing the estimated gross
dermal deposition by the quantity of the formulated product
handled and by the exposure time in hours to obtain the
respective normalized rate.
Even though only the exposure data from peer reviewed
journals or well documented studies are included in this report,
any attempt to statistically analyze the combined exposure data
for a body section under each operation is inappropriate because
of differences in study objective, test protocol, data quality,
4-4
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ccc'jPArrcnAi :e?hal exposure assessment • a review
September 30, 1996
and analytical method. Besides, for many of the operations,
there are only a limited number of data points and even fewer
data points for certain specific body sections.
For two operations, mixing of powder into a solution or
slurry and liquid mixing and transfer, a relatively large amount
of data are available. The outside clothing exposure data
(calculated gross dermal deposition) for these operations are
also plotted on scatter diagrams to show the spread of the data.
Only the time normalized data are included in these diagrams
since there are much fewer data on a quantity normalized basis.
Following the approach used by Van Hemmen (1992), the scatter
diagrams are used to determine an "Indicative 90th percentile
deposition" as a conservative estimate of potential exposure.
The "Indicative 90th percentile deposition" is chosen at a
rounded value that is exceeded only by approximately 10 percent
of.the data points for each body section.
Only the calculated gross dermal deposition at an exposed
body section or outside the clothing are included in the scatter
diagrams for analysis as potential exposure. Exposure inside the
clothing would have reflected the barrier effects of the clothing
which introduced additional variables (the fabric material, weave
type, worker habit, etc.) in estimating dermal exposure.
Therefore, such data are excluded from analysis of Indicative
90th percentile exposure at this time.
Since most of the data in this section were derived from
pesticide studies, an explanation of some- of the chemical terms
commonly used in pesticide application is appropriate (Farm
Chemical Handbook, 1992) .
Dry Concentrate: A dry, relatively free-flowing
powder containing the maximum
possible amount of AI. A wetting
agent amy be included so that the
mixture is ready to be dispensed in
water for spray application in
which case it is termed a dry
wettable powder. Without wetting
agent, but suitable for further
dilution to form a dust,' it is
called a dust base.
Emulsifiable Concentrate: Produced by dissolving the AI and
emulsifying agent in an organic
solvent.
Encapsulated: Pesticide enclosed in tiny capsules
(or beads) of thin polyvinyl or
4-5
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OCCUPATICMAL 3E?MAL EXPOSURE ASSESSMENT - A REVIEW
Septenter 30, '996
Solution:
Suspension:
Wettable Powderi
other plastic material to control
release of the chemical and extend
the period of diffusion, thus,
providing increased safety to
applicators as well as to the
environment.
Mixture of one or more substances
in another substance (usually a
liquid) in which all the
ingredients are completely
dissolved.
A powdered preparation containing
sufficient suitable surface active
material (wetting agent) so that
the powder will be wetted and
suspensible in water as a spray
material.
Particles of a solid or immiscible
liquid dispersed in a liquid or gas
but not dissolved in it.
A. Mixing of Dry Powder Materials
Data grouped under this operation pertain to dermal exposure
to workers who open bags of powder or granular chemicals and pour
the contents into a mixing tank; or scoop out a measured portion
of the contents for mixing with other dry chemicals or
substances. A summary of the available data is shown in Table 4-
l. Some of the- available data are expressed in terms of total
amount of AI deposited on skin surfaces per hour (mg/hr) and
usually represent the total exposure on uncovered areas of the
body. In other cases, data on dermal exposure may be reported
for various parts of the body..
Of the six studies cited, only one (Fenske et al., 1990)
reported u^,it area deposition rate at the body sections
monitored. Other studies reported primarily combined deposition
at unclothed areas of the body, typically including face, neck, V
of neck, forearms, and hands. Without the studies' original
data, it is impossible to back calculate unit deposition rate at
individual body sections. However, total gross deposition at
these unclothed sections (face, neck, and forearms1 • of the body
would be 104 mg based on the mean exposure data fr •. Fenske et
al. (1990) . This is comparable to the range of 27 :o 154 mg
derived from mean exposure of other studies that aiso include
hand exposure.
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OCCUPATIONAL 3E3MAL HXPOSURE ASSESSMENT • A REVIEW
September 30, 199$
The pesticides used in the six studies included in Table 4-1
were all described as dust or powder except the disulfoton used
by Wolfe et al. (1987a) which was described as "-granular." It is
unclear whether there was a difference in particle size among the
various dust, powder, or granules cited in the studies. Nor was
it clear whether grain size has any effects on dermal exposure
from the studies. Kissel et al. (1996b) conducted a series of
laboratory studies to investigate the effect of particle size and
moisture content on soil adherence to skin. Their results
indicate that for dry soil (<2% moisture) adherence rate in
mg/cm1 varies inversely with grain size and adherence occurs
predominantly for particles small than 150 n or even 6 5 p.. For
wet soil (12-18* moisture), adherence generally varies directly
with particle size.
B. Bagging
Bagging operation refers to the operation where workers fill
bags of dry powder mix at the filler spout, remove, and then seal
the bags. Three studies were found to have included data on
dermal exposure during bagging operations. A summary of these
data is presented in Table 4-2. The data generally represent
total hourly exposure at unclothed -areas of the body including
face, neck, Vof neck, forearms, and gloved or ungloved hands.
From these data, the gross dermal deposition including exposure
at ungloved hands ranged from 49 to 1986 mg for 1 hr. of.
exposure. One other study, by Comer et al. (1975), also
contained exposure data that included bagging.operations.
However, the reported exposure represented the combined exposure
during mixing and bagging operations and are excluded from this
summary.
4-7
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OCCUPATIONAL DERMAL EXPOSURE ASSESSMENT - A KEVIEU September 30, 1996
TABLE 4-1 DERMAL EXPOSURE DATA AND ESTIMATES FOR DRY MIXING OPERATIONS
Chemical
Foimulalion
Body Section Of Pad Locaiion
Reported
Exposure*
Exposure
Duration
(hrl
Quentity
Handed
(toll
Estimated
Grose
Dermal
Deposition" *
Estimated
Gross
Deposition
by Quantity
Oig/cm'/lbl
Estimated
Gross
Deposition by
Time
Ipg/cm'/hrl
50% oor
Face.neck, V of neck, fwuimi, and hands
Iiwviwuii protection)
Face, met, and V of neck only IwJHfl
(mg/hrl
13.3-44.7132.7)
4.2-16.2112.8)
0.6-1.0
0.6-1.0
N.A.
N.A.
(mfll
28 6
88.4(66.4)
8.4-
38.4(25.8)
-
Wolfe and
Armstrong,
1971
Expoaura from 6 measurements mining DOT In formuisllng plama. Hand ••ootwa liom hand wssh. Exposure dataimined liom layered flxuie pad*.
Eapoaura duration and amount ol DOT handled not repotted. 1 hr exposure sssumed. Shan sleeve shirts and long panu with minimum protection (no
glowaal. ff£ uaad Included coverage. respirator. and iuUmt glivii.
10% Duulloton
Faca. nack. V of nack, forearms. and handa
(mg/hrl
27 ±36
N.A.
N-A.
Imgl
?7*36
..
Wolfe el el ,
1978a
tifHiwa horn 7 mee*u»menu duting mining ol dry grammar 10% dlautfoton formuletion to dry liaiiaf. Layaiad geuze absorbent pads wtra attached
lo worker's clothing. Hand expoeufe liom hand wflh. No glow* used. Quantity o< chemicals handled and duration of exposure not reported. 1 hr.
exposure assumed. -
26% Paiaituon
Face, neck, V of neck, forearms, and hands
(mg/hrl
38.4*37.6
0.6-1.0
N.A.
(mg)
163.01160
..
..
Wolle bi al ,
1978b
Exposure from 8 measurement* dufmg mining In perethlon formulating plant*. Exposure determined from layered gatue pad*. Hand exposure liom
hand «raoh. Workera mmra ahoft aleeved alMrte, long penis, no gtowee. Work leaf it 30-40 minute*. amount of chemicals processed not reportad. 1
hour exposure aaaumad.
Depending on the original data reported, range* with the mean value w p*ftntheais; mean value ± standard davialion; 01 only the mean value tin paiemheses) is presented
Gatculated by dividing percent Ioi mutation into lha reported |«poiui* and extended fw tha duration whcra appfopuata; data not proved unlets duianon data it available or assumed
4-8
-------
OCCUPATIONAL DERMAL EXPOSURE ASSESSMENT - A REVIEU September 30, 1996
TABLE 1-1 DERMAL EXPOSURE DATA AND ESTIMATES FOR DRY MIXING
OPERATIONS (Cont'd)
CharmcAl
FoimuUuon
Body Saction «f tod Location
Reponad
Exposura*
Exposure
Duration
(hrl
Quantity
Handled
llbsl
Esumstsd
Gross
Dsrmsl
Deposition * *
Eslimsted
Gross
Deposition
by Quantity
Ujg/cm'/lb)
Estimated
Gross
Deposition by
Time
U/g/cmJ/hr)
Relaiaiuo
6% Ckpun
Faca. neck, V of reck, outdoor
Hands, outdoor
Faca, neck, V of nack, indoor
H4nda, indoor
Img/hrl
4.6*0.2
3.0a 2.0
0.86*0.41
o.oa*o.o7
1
1
1
1
HA.
N.A.
HA.
N.A.
(jjg/cm'l
112.616 0
73.2x48.8
23.B± 10.3
2.2*1.7
--
) 12.5 * 5 0
73.2 * 48.0
23.8* 10 3
2.2* 1.7
Stevens and
Devil, 1981
Total exposure while filling iha hoppers of aaad dueling machines with Captan (1 1/2 lbs. of Captsn dust par 100 lbs. of cut poiatossl. Woikan wom
long-aleewad shirts or jackata. with haad covering and canvaa-back laathar glouaa. Exposure other than hands wara meesursd with multi-layered gaute
psda; hand exposure was maasurad with hand rinse techniques and axposura dursUbn tanged 3/4 to 2 lua (1 hr awumad). 3 outdoor and 7 3 indooi
measurements mada akin aurfaca araaa In EPA 1B87b used to calciiata groat dapoaltion from laponad axposura.
LifKUn*
| (concminlion
mi r«pod«d)
Chast
Alma
Hands
(mgihil
<0.1
<0.1
91.42 A 64.8
N.A.
NA.
NA.
N.A.
NA.
N.A.
NA.
N.A.
N.A.
--
-
Grey et al .
1983
Exposura maasurad while emptying bags of Manab-lindane into tha hoppara of commercial aaed traalet. Approximately 18.000 to 20,000 kg ol wheat
aaads are treated par hour. Expoeura wae found only m tha hands; worksra checked Iha uniformly of application using thaw bsra hands. Dermal
exposures other than hand expoauraa wara maasurad with multi-layered gauxa pads. Hand exposures were maasurad with tha rinse technique.
Exposure duration and application mas not reported. 2 maaauramanta mada.
• Depending on thi originet data rcpontd, ungii wiih the mean value in poiwiticm; maan vRkia t tundird deviation, or only the mean valua (in parentheses) is presented
"• CeJculeted by diyutng percent lotmuleiion into the reported aufwiuia and extended lex the duration what* appropriate; data no I provided unless duration data is available or aiiumoa
4-9
-------
0CCUPA1IONAL DERMAL EXPOSURE ASSESSMENI - A REVIEU
Septeaber 30, 1996
TABLE 4-1 DERMAL EXPOSURE DATA AND ESTIMATES FOR DRY MIXING
OPERATIONS (Cont'd)
1 Chemcel
j Formulation
Body Section or P»d Location
HSponed
Exposure*
Exposure
Duration
(hi)
Quantity
Handlad
(lbs)
Estimated
Gross
Oat ma)
Oapoanion * *
Estimalad
Gross
Oaposition
by Quanirty
(pg/cm'/lb)
Estimated
Gross
Deposition by
Tim*
(pg/cm'/hrl
Hefwanc*
18 76* Lindane
(rug)
(pg/cm*)
(pg/cm'/lb)
(pg/em'/hr)
Fenske al al .
Cheat. (Inside dollung)
0.07 0.71(0.461
0.4
7.6
0.11-1.07
O.Ol-O-14
0.28 2 68
1990
Back. (Inaida clothing)
0.11-2.69(0.711
0.4
7.6
0.17-3.89
0 02 0 62
0 41 9 73
Forearms. (Inalda clothing)
1-31-16.7(6.43)
0.4
7.6
6.77-73.8
0.77-9.81
14 4-184
Upper iim, (Inaida cMHtagl
0.12-2.81(1-12)
0.4
7.6
0.22-6.33
O.O3 0.71
0 66 13 3
Upper ligi, (Inaida clothing)
0.08-9.32(2.88)
0.4
7.8
0 11)3 0
O.OM.74
0 28 32 6
Lower toga. (Inakte dtlhlnol
00.33(0.16)
0.4
7.6
0-0.74
0-0.10
01.86
Chaal. (ouim clothing)
0 92 7.640.21)
0.4
7.6
1.38-11 8
0.18-1.67
3 46-29 4
Back, (ouim clothing)
0.66-4.66(2.48)
0.4
7.6
1.28-8.88
0.17 0.82
3 IS 17.20
Forearms. (ouim do thing)
6.67-61.M17.8I
0.4
7.6
24.6-228.3
3.27-30.4
61.4-670.8
Uppw Mtne, (outer clothing)
0.99-10.1(4.43)
0.4
7.6
1.81-18.6
0 24-2.46
4.64-46.3
Upper lege. (ouim clothing)
2.90-132.6134.0)
0.4
7.6
4-06-186.1
0.64-24.7
10.1 463
Low* logt, (ouim clothingl '
0.43-6.96(1.341
0.4
7.6
0 86 13.3
0.13-1.78
2.41 33.3
Handa. (maid* gloveal
(0.74)
4.81
0.64
12 0
tMpoaad ha ad Mid neck
(1.72)
-
-
WorkMa wore long aleava shirts. long pants, glovaa.and respitalora. Absorbent pa da with Impanioui backing waia placed outside and inside the
doihing. Exposure was measursd tot manual uealmant (scooping Undana from bag* and mixing with a slick) o( wheel grain with Lindane powder
tormutetion m planter boxes. Hand atprnwa measured with a handwash tachniquf. AVMiga duration of mixing waa 24.1 mnuiai and 3.4 kg ol
lindana lormuletlon wea handtad. 12, measurements mada.
" Oapanoing on in* onflinil dat^ reported. rangea with th* main value in parenthesis; mean value t. standaid deviation; or only lha maan valua (in parentheses) is presented
Celculaikd by dividing percent formulation into lha reported ikjmmii and extended 1« I he duration wtwa appropriate, data not provided unlasi duialion data is available oi assumed.
4-10
-------
OCCUPATIONAL DERMAL EXPOSURE ASSESSMENT - A REVIEM Septcebar 30. 1996
TABLE 4-2 DERMAL EXPOSURE DATA AND ESTIMATES FOR BAGGING OPERATION
1 Chamk:*!
! Foimutauon
Body Sacuon ot Pad Upatfon
Haponod
Exposure*
Eipoauie
Duration
lhr|
Quantity
Handled
l>M)
Eatlmaied
Otoaa
Oaifnal
Oepoattion"*
Eaumaled
Groaa
Depoeilion
by
Quantity
jag/em'/fe
Eilimiltd
Gioii
Deposition
by Timt
M0/cma/hr
1
Ri(«f»nc«
| 60* DOT
Faca. nock. V of nack. Ioimm, and
handa (workaro wntw IMad 4 * ft ft baga
at itia ipoui at Hani A. lafcilmi
protection)
(mg/hr)
•6-W34624.6)
0.6-1.0
N.A.
(mgl
lao-isae
--
Wo4U tnd
Atnuifoog,
1071
Faca. nack. V ol nack. lot aw ma. and
handa Iworfcara who Wad 60 k bap at
lha spout ai Plant A, mlrkmtm
protection)
106-2271163.6)
0.6-1.0
N.A.
210-443
Faca. nack. V ol nack, faraaima, and
handa Iwortara who IMad 4 fe baga (1
tha (pout at Plant 1. mtnJmui
protection)
24.ft-34431.3)
0.6-1.0
N-A.
46.2-66
Faca, nack, V ot nack, (workora who
IIM 4k (fe baga at tha apout al Rant
a. wjrrei
24.4-124(72.7|
0.6-1.9
N-A.
62.6-246
'
96-310
Faca, nack, V ol nack, Iwoikaia who
IWad 60 k baga al tha apout al Rant A.
w/PPCI
24.3-17.6(43.61
0.6-1.0
N>.
46.6-176
01-219
Faca, nack. V ol nack. Iworkara who
IWad 4 ft baga al lha apout at Plant 1,
wIPNI.
7.6-16.6114.31
0.6-1.0
N-A.
16.6-36.2
-
20-48
No tnlormatkin on (ho numfcaf ot Ugl handlod paf unit time. E«poaura datannlnad mMi layorad gauia pada and handwaah. Each axpoaura
moaaurameni laatad 30-00 mlnutaa. 1 hr aapoaura aaaumad. No (WOlacUva clothing at g>o»aa uoad undar mlnfcuuia protection. Iff uaod
Included covataMa. teepfcaMx. and iuMw gfovea. 4-5 meaauteaaenta ma da lot each taat. CPA IM7a aUn areaa uaad lo calculate groaa
dopoeition by time. vrfta>a appbcafela.
* DapandwQ on lha original data npMtd, ungu wtlh ih« maan vaiua In patanlhaaia; maan value t iiwdvd danatton; 01 only lha mean vaiua (tn paranthaaaal la praaantad.
* CaJcutalad by dividing patcanl lofmulalion into lha lamUM aapoauia and aaiandad lot lha duration wttara BlHMPptiata; data not ptovidad untax duration data la availabla cm aaauinad
4-11
-------
OCCUPATIONAL DERHAL EXPOSURE ASSESSMENT
- A REVIEW
StptMter 30, 1996
TABLE 4-2 DERMAL EXPOSURE DATA AND ESTIMATES ON BAGGING OPERATION (Cont'd)
I Chamictl
1 fotmul>Uon
Body Section oa M Location
Reported
Eapoaura*
Expoaura
Duration
thai
Quantity
HandUd
Ibel
Eatamatad
Oaoaa
Dartnal
Deposition"
Eailmatad
Gioaa
Oapoeition
hy
Quantity
jig/cm'/to
Eatlmaied
Croaa
Depoailion
by Tuna
jig/cm'/lif
Ralaianca 1
0 b*
Ouutfolon
Faca, neck, v ol nack, loaeaama, and
handa
Imflffifl
t.2±2.D
N.A.
N.A.
(tng)
240* 400
--
--
Wolla at al.. R
1978a 1
Expoaure horn ¦ ipeaauremeou uMi Wkn
workea'a ctalMng. Hand eapoetae kw ha
enpoaure aaaumod.
bege (Ml peelldde-laftWiai anta at lt>a IMea spout. Layaiad geuie pada Mia attached lo
mdwaah. No glona uaad. Nuaifaar o< hags handted and duration •/aapoeura not reported. 1 h».
1 26%
1 Pmihion
Faca. nack. V ol nack, for ear me. and
handa
Ima/lwt
•2.t*M.4
O.H.O
N.A.
Imgl
32«*3»t
--
-
Wolf® m\ ml . 1
18*86 I
J
Tola) maan eapoeura liona 17 meeeuremar
uaing leyarad game pade and handwMh.
aaaumad.
iU while MMng the ba
lk—t»i ol ba^a ham
iga at Iha apoul. Expoauaa determined during 30 lo 80 aninutaa of operelkm.
•ad not reported. Wort era mora work doth, no gtovaa uaad. 1 hr. aipowia
" D»p»ndino on lh» original dais laporlad. iwgti with Iha mmmn value in paianlhaau; (Man vaJua t alandafd daviatlon; or only Iha maan valua (in paranihaaaa) i< praaanud
• • Calculated by dividing percent formuielion Iota the reported •¦poauta and amended lor iha duration where appropriate; data not provtded unlaw duraiion data I* avuUbta o> aaaumad
4-12
-------
OCCUPATIONAL C'ERRAl EXPOSURE ASSESSMENT • A REVIEW
September 30, 1996
C. Stacking
A summary of dermal exposure data related to stacking
operations is presented in Table 4-3. Workers who perform
stacking operations generally stack full bags of powder or
granular material on pallets, operate the machine for closing bag
tops, or pack bags in cartons for shipment.
The three studies identified that contain -stacking operation
dermal exposure data are afll from the same research team. They
reported only total exposure at unclothed areas of the body
including face, neck, V of neck, forearms, and ungloved hands.
Based on 1 hr. of exposure, total gross deposition calculated
ranges from 3 0 to 4 80 mg.
4-13
-------
OCCUPAIIONAL DERMAL EXPOSURE ASSESSMENT - A REVIEW
SaptMbtr 30, 1996
TABLE 4-3 DERMAL EXPOSURE DATA AND ESTIMATES FOR STACKING OPERATIONS
1 Chamcal
1 Fotmulatnn
BodyiSaction MlMlMaiM
Haportad
Eapoauia*
Eapoaura
Duration
Quantity
Handlad
UM
Eaiimatad
Qroaa
Daroial
Oajuwininn**
Eawnaied
Qioaa
Oapoatuon
by Quantity
MB/cm'flb
Eatimatad
Cioai
Oapoaition by
Tuna
H)/cin'lhi
Bafaianca
1 60% DOT
Ftca; nack, V at nack. (oiaaraa, and
unglovad tianda
Ina/hrl
44.2-l44.7IM.il
0.6-1.0
Nik.
igi handlU not rapartad. 1 In. aipowa aaaumad.
26%
Paialtuon
Faca. nack. V ol nock, loraatm, and
handa
(¦(Ail
34.0*42.0
O.ft-I.O
NA.
(*0t
134*244
-
-
Wolla al al..
1878b
I
Total axpoauia liotn 26 mmmaanM
packing baga In can ana fo> aMptnani.
Iw. aipgawa aaaumad. Quantity at bai
SI
111
!
¦jlarton oMa
puia pada ai
atorapa pabau. epotatlng tag cktaura machina*. or
yi Madwub during 30 to 60 aamutaa ofMrauon. t
* OapandmQ on tha otlpmal data taportad. lanfla wttlt am vtluM In paiantftaata; maan value * uandard davtaUon; or only sha maan vaiua (in paianihaaial ii piataniad.
' * CaicuUtad by dtvMmg parcant formdauon M« ttta rapeIM aapoataa and aaundad lot ttta duration ttdtara aimHraHi; Oau not provldad untaaa duiaiton ia availabta o< asiumad.
4-14
-------
3C:.'P*r;:NAL 0E3XAL :XP0SU9e ASSESSMENT • A REVIEW
Septenrer 30, !?
-------
OCCUPATIONAL DERHAl EXPOSURE ASSESSMENT - A REVIEW
Septeaber 3Qa 1996
TABLE 4-4 DERMAL EXPOSURE DATA AND ESTIMATES FOR MIXING OF POWDER INTO LIQUID
1 1
Chamical
Fwmuidton
Body Saction « Pad Location
Raportad
Eipoiuia*
Exposure
Duration
Quantity
Handlad
Oba)
Estimated
Gioaa Dermal
Deposition"
Eitimatad
Gioaa
Da position by
Quantity
(jig/cm'/lb)
Etnmatad
Gross
Deposition by
Tima
tig/cmJ/hi|
Reference
Ntliolan
60% powdar
Foraatma (insida clothing)
Uppai Lao* lintlda clothing)
Chaai (malda clothing)
Back (inaida clothing)
Fenaima (outrida clothing)
Uppat Laga (outalda clothing)
Chad loutuda clothing)
Back loulilda clothing)
Hands tmaida glovaa)
(pg/cm'l
0.028-0.053
0.013-0.10
0.008-0.071
0.003-0.0)1
0.6-1.78
0.28-2.12
0.1B4.88
0.O7-O.41
673-1228
0.23-0.36
0.23-0.36
0.23-O.36
0.23-0.36
0.23-0.36
0.23-0.36
0.23-0.36
0.234.36
0.23-0.36
N.A.
N.A.
N.A.
N.A.
N.A.
N.A.
N.A.
N.A.
N.A.
(pg/cm'l
0.066-0. 10
0,020-0.20
0 010-0 14
0.008-0.022
1.0-3.68
0.68-4.2
0.38-1.8
0.14-0.82
1146-2468
-
0 16 0 36
0.096 0 69
0.060-0.21
0 018-0.072
2.86-12.67
2.62-14.9
1.08-6.67
0.44-2.66
1.4O-3.00
Maddy al al .
1980
Eipoauraa from 6 maaauramanti during mining and loading ol wattabla powdar. Workara woca long-alaavad ahirta. long panu. watarprool hat. glovaa.
boots. and (aspirator. Exposure datatmnad «dUi pada ma da out ol a top Iqyar of cotton duck cfcMti and Innai Isyars ol gauia pmnad to axtanor ol
diapoaabla covataka. Hand amaoaura dataonlnad wWi tha hand rinaa tachniqua. Ewpoauta niaursd tiff muing and loading oparatlon ol approximaialy
16 to 30 mlnutaa.
B Cutiivl
| 60-80%
R Watiabla
Powdac
Chad (outside)
Back (outtida)
Shouidars (outsida)
Foroarma (outsida)
Handa (without glovaa)
' Harw^a (wtth glovaa)
(ug/cm'/hr)
0.7-48.13
0.3-12.81
0.7-26.12
0.7-48.20
2.87-380
3.43-8.86
3-14 mtn-
3-14 mln.
3-14 min.
3-14 mln.
3-14 min.
3-14 mln.
N.A.'
N.A.
N.A.
N.A.
N.A.
N.A.
1.4-61.42
0.24-16.14
1.4-31.40
1.4-67.76
3.34-487
4.28 12.32
Maitlen at al
1382
Exposure liom 3 aipatunanu for 80% powdar wtth up to 10 (apfecataa. and 2 axparimants lot 60% powdar with 1 taat aach (14-20 maaturamami).
Eaposura taponad lot total pat body (action, valuaa ata back ralculatQrt to ahow par unit aiaa axpoauta using akin aurfaca araa ol Wfi, 1987a. Ringai
ol malng tlmo shown; total amount ol 'formUatian not raportad. Hand aaipoaura from rinaa pcocadura. othar axposwa from pada.
• D«pand«o0 on tit* ongmai d«ia taportmd. imgit wtih Itw tntmn w»lui in pwwithtui; moan vilut ± it«ndar
-------
OCCUPAT10NAL DERMAL EXPOSURE ASSESSMENT - A REVIEW SeptoAer JO, 1996
TABLE 4-4 DERMAL EXPOSURE DATA AND ESTIMATES FOR MIXING OF POWER INTO LIQUID (Cont'd)
Chtrrwcftl
Body Sacdon
ipoaed akin area and tor Inatda peraonal clothing (coverall). Reported inaide enpoiure calculated by auihora liom
oulalda pad data with a tealad penetration (actor ol 0.63. V
aluaa ahown here lot nut aula clothing expoaure ara back calculated. Raaultt lor 4 daya ol
i
taating and laportad aa iMy expoetae. Hand exposure Irorn rinae procedure-
Muter Aoeders win and load herbicide. refuel planaa. and claan windshields
¦
Daily axpoaura aaaumed to be 8 hi. and akin aurfaca araaa In EPA 1967a uaei
1 for calculation of gnu darmai deposition. Lafl axpoaura was high dua
1
to repealed contact wtlh tha a pray noule during rafuaimg.
' Depending on the original data reported, ranges with lha main valua in paranthaais; maan valua ± standard davialion; or only lha maan valua (in paianlhesas) it presented
• ¦ Calculated by dividing parcant InmiUiion inlo tha raponad axpoaura and axtandad loi tha duration wtvare appropriate, data not provided unless duiation data it available or asiumod
4-17
-------
OCCUPATIONAL DERMAL EXPOSURE ASSESSMENT * A REVIEW Septeatoer 30. 1996
TABLE 4-4 DERMAL EXPOSURE DATA AND ESTIMATES FOR MIXING OF POWER INTO LIQUID (Cont'd)
¦
Chemical
Body Section M Pad Location
Reported
Exposure
Quantity
Estimated
Eatimatad
Estimated
Ralaience
Formulation
Exposure*
Duration
Handiad
Gross Dermal
Giosa
Gioti
IMui
Deposition ' *
Dapotmon by
Deposition by
Quantity
Time
tpg/cm'/lbl
Ojg/cm'/hi)
Foaelvt-AJ
'
-------
FIGURE 4-1 ESTIMATED GROSS DERMA] )SIT10N DURING MIXING OF
POWDER WITH L.TQUID
s «
SB 4
9' ;
B ?
(W 6
5
4
3
2
I
1 -
* .
I
Head or Ficc
i ¦
i
•
•
•
t
•
•
•
•
•
•
«
•
Shoulders
• o • _ «« • mm • •
i
*
• • • • •• •••••••• •
Chest
• • • •
i «
• * • •
• • • • • •••»• «• I • • •
Back
• • • • •
Upper Anns '
4
1 1
~ " '
• •• • «•
Forcamu
• • •• • • •
» • ••
•
I
1
•
Upper Legs
«a • • •
Lower Leg» ' ¦
*
iUndi
• • •••• • • • • • •
6 ~
0.01
0.1
I MwUydaL. 1910
4. MmuHiI.191]
I 10
Gross Dermal Deposition, ug/cmA2/hr
2. EvofaMlJkHofe.1912
3 ICaarr st iL, |9SS
100
1.000
). Mutlcnrttl. 1912
6 Fottltc d al, 1917
Legend:
¦ Mean +/- standard deviation | 1 Range
I Mean
* Beyond scale
4-19
-------
OCCUPATIONAL OERMAL EXPOSURE ASSESSMENT - A REVIEW
September 30, 19"?6
TABLE 4-5
INDICATIVE 90TH PERCENTILE ESTIMATED GROSS DERMAL DEPOSITION
FOR MIXING OF POWDER WITH A LIQUID
Indicative 90th Percentile Deposition
Time Normalized
H g/cm2/hr
Quantity Normalized
^g/.cm2/lb
Head or Face
120
0.4
Shoulders
30
Upper Arms
0.5
0.6 .
Chest
40
1.0
Back
15
0 .15
Forearms
200
2.0
Upper Legs
15
3.0
Lower Legs
0.1
0.1
Hands
300
1.5
Determined from data in Table 4*4 and Figure 4-1 aa the value exceeded only by approximately 10% of the data
points reported for each body section; rufcar of data points variea between body sections and between
normallzfnfl factors.
4-20
-------
OCCUPATIONAL OERHAL EXPOSURE ASSESSMENT - A REVIEW
September 30, 1996
E. Liquid Mixing and Transfer
Liquid mixing and transfer operations refer to operations
where one liquid is added to another liquid either through tank-
top transfer or through an enclosed pumping system for mixing.
Depending on the type of transfer operation (e.g., manual liquid
transfer vs. automated closed system pumping), exposures could be
quite different. Available exposure data from 10 studies are
summarized in Table 4-6. Other studies on liquid mixing
operations, including those of Lavy et al. (1980), Wojeck and
Nigg (1980), and Byers et al. (1992) did not report the
concentration of the formulated pesticide used which made""the
calculation for gross deposition impossible. These data are
therefore excluded. One study by Knaak et al. (1989) contains
some incomplete data on dermal exposure for liquid mixing
operation and is also not included.
In pesticide application, liquid transfer occurs when an
emulsifiable concentrate, a solution, or a suspension is mixed
with a diluent for spraying. Except for spills and .splashes,
dermal exposure is likely to be the result of incidental contact
with contaminated equipment surfaces. Thus, personal work habit
can play a critical role in determining the extent of exposure.
For instance, Knaak et al. (1992) found a high exposure at the
lower leg because most of the mixing/loading operations studied
consisted of pouring liquid from one container to another below
the waist level and liquid splashing might have caused the
relatively high exposure at the lower part of the legs.
Unusually high exposure at the legs was found by Knarr et al.
(1995) due to frequent' contact with spray nozzles during the
loading operations. Conversely, Chester et al. (1987) found most
of the exposure was concentrated in the arras, trunk, and hands.
Lavy et al. (1980) reported high exposure at the thighs and
observed that workers frequently rubbed their hands against their
pants at the thigh area.
Comparing the estimated gross dermal deposition at the same
body section from the studies included in Table 4-6, one will see
a wide range of variations. A scatter diagram of the data as
shown in Figure 4-2 further illustrates, this point. Only the
data from-:) of the 12 studies are shown in Figure 4-2; data from
the remaining 3 studies do not provide- normalized deposition at
individual body sections. Of the 12 studies included in Table 4-
6, three are related (the last three studies in the table) to
exposures during closed-system pumping operations. The'range of
exposures reported in .closed system pumping are generally at the
mid- or lower-range of those reported for tank top transfers.
These data are included in the scatter diagram but are analyzed
separately for the Indicative 90th Percentile estimates. Based
on the data points pertaining to open mixing shown in Figure 4-2,
4-21
-------
OCCUPATIONAL DERMAL EXPOSURE ASSESSMENT - A REVIEW
September 30, 1996
the Indicative 90 Percentile estimated gross depositions for
various body sections are estimated as: hands, 200' ^xg/cm2/hr;
forearms 10 /xg/cm2/hr, chest, 8 /ig/cm2/hr; upper legs, 5.0
Hg/cm2/hr, back 3.0 ^g/cm2/hr, shoulder, 3.0 ^g/cm2/hr; lower
legs, 1.0 iig/cm2/hr; and head, 0.1 /xg/cm2/hr. For the quantity-
normalized data, the Indicative 90th Percentile estimated
depositions are: hands, 100 ^g/cm2/gal; forearms, 4.0
/xg/cm2/gal; chest, 0.4 ^g/cm2/gal; upper legs, 10 ^g/cm2/gal;
back, 0.2 /ig/cm2/gal; shoulders, 0.3 M5/cm2/gal; lower legs, 2.0
/ig/cm2/gal; and head, 0.4 /ig/cm2/gal. Table 4-^ summarized these
data.
4-22
-------
OCCUPATIONAL DERMAL EXPOSURE ASSESSMENT - A REVIEU Septeofcer 30, 1996
TABLE 4-6 DERMAL EXPOSURE DATA AND ESTIMATES FOR LIQUID MIXING OR TRANSFER OPERATION
Chemical
Body Section or Pad Location
Reported
Exposure
Quantity
Estimated
Estimated
Estimated
Reference
Formulation
Exposure*
Duration
Handled
Gross Dermal
Gross
Gioss
(hr)
(gallon)
Deposition*"
Reposition by
Deposition by
Quantity
Time
(/jg/cmx/gal)
(/
-------
OCCUPATIONAL DERMAL EXPOSURE ASSESSMENT - A REVIEW September 30. 1996
TABLE 4-6 DERMAL EXPOSURE DATA AND ESTIMATES FOR LIQUID MIXING OR TRANSFER OPERATION
(Cont'd)
Chemical
Body Section or : i oca lion
Reported
Exposure
Quantity
Estimated
Estimated
Estimated
Referenco
Formulation
Exposure*
Duration
Handled
Gross Dermal
Grosa
Gross
(hr)
(gallon)
Deposition**
Reposition by
Deposition by
Quantity
Time
(pg/cm'/gall
Org/cm'/hrl
EPN 13 4 lbs/gal.
lmg/8-hf)
(mgl
Atallah. ol
42%)
Faoa, V of neck, back of neck, for ear ma,
8.3±4.3
1.67-2.83
N.A.
3.76
--
al.. I9U2
and henda (unclothed regions)
1.67-2.B3
Total (on cloth and exposed akin)
86 ±62
N.A.
39.3
--
-
Total expo aura of loadaia reported for undothad and clothed region of tha body Irom denim patch aamplea axirspoleted to 8-hr exposure Itom 3 tests.
Loadera opened Inaacticida contalnar uanaferrad it to hofcfcng tank.
mixed, than attached to e hoee to uenatei Hie
.
-------
OCCUPATIONAL DERMAL EXPOSURE ASSESSMENT - A REVIEW Septenber 30. 1996
TABLE 4-6 DERMAL EXPOSURE DATA AND ESTIMATES FOR LIQUID MIXING OR TRANSFER OPERATION
(Cont'd)
Chemical
' ii gemag ' '
Body Sac lion m Pad Location
Reported
Exposure
Quantity
Estimated
Estimated
Estimated
RefarenLe
Formulation
Exposure*
Duration
Handled
Gross Dermal
Gross
Gross
(hr)
(gallonl
Deposition" *
Reposition by
Deposition by
Quantity
Time
Osg/cm'/gal)
UiQ/cm'/hi)
Estaron 99
(mg/cm'l
(/jg/cm'l
Levy ot
(4 lbs/gal. 48%
Right wrist (outside)
0.24-9 49 mg
13-78 mm
90 gal
0.6-19.8
0.006 0 22
1 25 15 2
al . 19B2
2.4-D)
Lall wrist loutsidel
0.06-10.0 mg
13-78 min
90 gal
0.10-20.8
0 001 0.23
0 26 )6 0
Neck (outaida)
0.10-0.29 mg
13-78 mm
90 gal
0.21 0.60
0.002-0 007
0 16-1.61
Head (outaida)
0.47-24.8 mg
13-78 min
90 gal
0.98-61.7
0.011-0.67
2 46 163.2
Right wrist (under Tyvak)
0.21-4.72 mg
13-78 min
90 gal
0.44-9.83
0.006-0.11
2 02-31.05
Lett wnat (under Tyvak)
0.06-9.28 mg
13-78 min
90 gal
0.10-19.33
0.001-0 21
0.48 44 4
Mack (undar Tyvak)
0.06-0.10 mg
13-78 mm
90 gal
0.10-0.21
0.001-0.002
0.16 0 96
Head (undar Tyvak)
0.36-6.30 mg
13-78 min
90 gal
0.73-11.0
0.008 0.12
1.04-34 9
Exposure ol 3 batchman-loadar mixing and loading formulation with open tanka on 3 day*, each lading 13 to 78 minutaa. Patch ol outer clothing (denim)
uaad aa pada lor exposure lasting.
4£ Xcuabin (4
pg/cfn'/hr
>jg/cm'
Nigg and
lb«/a«l 48%)
Back (outaide clothing)
O.Q9 ± 0.02
N.A.
1.126
0.19*0.04
0.17*0.04
0.09*0 02
Stamper.
chloiobetuilata
Chant (outaida clothing)
0.19 ±0.06
N.A,
1.126
0.40*0.10
0.36*0.09
0 19 ± 0.05
1983
Shouldera (oulaide clothing)
0.16*0.04
N.A.
1.126
0.31 *0.08
0.28*0.07
0.16*0.09
Wnat (outaida do thing)
0.46 ±0.13
N.A.
1.126
0.94*0.27
0.83*0.24
0.45*0.13
Shin (outside clothing)
0.66 ±0.32
N.A.
1.126
1.38 ±0.67
1.22*0.59
0 66 10.32
Hand (outaida clothing)
1000± 300
N.A.
1.126
2080 * 626-
1860*665
1000*300
Forearms (outaida clothing)
1.44*061
N.A.
1.126
3.0*1.27
2.67*1.13
1.44*0.61
Thigh (outaida dothingl
4.06 ±1.49
N.A.
1.126
8.44*3.10
7.60*2.76
4.06* 1.49
Fowarma (inaida clothing)
0.09 ±0.03
N.A.
1.126
o.is±o.oa
0.17*0.06
0.09*0.03
Thigha (inaida clothing)
0.03 ±0.02
N.A.
1.126
0 04 i u 04
0 66 i 0 04
0 03 t 0 02
Expoaure at outaida clothing (except otherwise notadl ol 18 replicataa. For torairma end thigh aemptea, 12 raplicatea ware mada lor outside patch
sample*. and 21 to 23 replicataa for inaida patch aamplaa. Workars wore long alaavad shirts. long panta, wida-brimmed hats, leather shoes, and cloth-
linaa rubber glovea plua, a rubber apron. t|and exposure Irom glova waah. Duration not raporiad. assumed 1 hr. exposure lor gross deposition calculation.
* Depending on the original data reported. range* with the mean value in parenihesia; mean value * standard deviation; or only tha mean value (m parentheses) is presented.
*" Calculated by dividing percent formulation Into tha raporiad exposure and amended for tha duration wftara appropriate; data not provided unless duration data is available or assumed
4-25
-------
OCCUPATIONAL DERMAL EXPOSURE ASSESSMENT - A REVIEW Septeaber 30. 1996
TABLE 4-6 DERMAL EXPOSURE. DATA AND ESTIMATES FOR LIQUID MIXING QR TRANSFER OPERATION
(Cont'd)
Qitrmcal
Body Section w P«d Location
Raportad
Expotura
Quantity
Eatimated
Estimated
Estimated
Reference
Formulation
Expoaura*
Duration
Handled
Grosa Darmal
Gross
Gross
(hr)
(galonl
Dapoaiuon**
Reposition by
Deposition by
Quantity
Time
(jig/cm'/gal)
Ipo/cm'/hrl
Diquart 36.3%
pg/cm'ftir
l/ig/cm1)
Wo|eck et
Coocintrid
Chad (outaida cloUung)
0±0
N.A.
N.A.
O
--
0x0
el.. 19U3
Back loutakta clolhlngi
0*0
N.A.
N.A.
0
~
0±0
Shouldara (outaida clothing)
0±0
N.A.
N.A.
0
-
0±0
Forearms (outaida do thing)
0.03 ±0.03
N.A.
N.A.
0.0910.09
--
0.09x0 09
1
Handa (on gloval
0.11 ±0.0?
N.A.
N.A.
0.31 ±0.20
--
0.31 £0.20
i
Stuna (outaida do thing)
o.oe±o.04
N.A.
N.A.
0.17 ±0.11
--
0.1 J ±0.11
J
Thighs (outaida clothing)
0.02 ±0.02
N.A.
N.A.
0.06 ±0.06
-
0 06 ±0 06
|
Exposure during opan mixing from 3 lapiicationa. The mixer wore normal work clolhea and glovaa. Pada attached outside tha clothing.
Hend exposure
1
from cotton glova samples. Exposure duration not reported, 1 hr. asaumad for groaa darmal deposition.
| Motinata (Ordrarn
(mg/dayl
(pg/dm'l
Knarr et
8E selective.
Trunk (inaida clolhlngi
0.22 ±0.22
N.A.
41
0.034 ±0.034
0.0008 ± 0.0008
--
al . 1985
91% liquid)
Arma (inaida clothing)
6-0± 16.0
N.A.
41
1.6±4.3
0.04±0.10
--
Laga (inside clothing)
1300x3100
N.A.
41
23O.0± 648
6.61 ±13.4
--
Head (unclothed)
0.007 ±0.006
N.A.
41
0.006 ±0.006
0.0002 ± 0.0001
--
Faca and neck I unclothed)
0.26±0.30
N.A.
41
0.36 ±0.41
0.009 ±0.01
-
Handa
0.46 ±0.36
N.A.
41
O.BO±0.47
0.015±0.012
-
Trunk (outaida clothing)
0.73 ±0.73
Nik.
41
0.11±0.11
0.003 ±0003
..
Arma (outaida clothing)
20.0 ±63.3
N.A.
41
6.33 ± 14.2
0.13*0.36
-
Laga (outaida clothing)
4333 ±10330
N.A.
41
768 ±1630
18.7x0.46
Exposure reported only for axpoaad akin araaa and for Inaida tha clothing. Reported inaida axpoaura calculated by authora from outside ped data with a
penetration factor of 0.3. Valua* ahown hare for outaida clothing axpoaura are back calculated from inaida clothing data. Results from 4 days of tasting
and raportad as daily axpoaura. Exposure at l<
sgs ware 'extraordinary* on 3 of tha day*. (Without thaaa 1)
-------
OCCUPATIONAL DERHAl EXPOSURE ASSESSMENT - A REVIEU September 30, 1996
TABLE 4-6 DERMAL EXPOSURE DATA AND ESTIMATES FOR LIQUID MIXING OR TRANSFER OPERATION
(Cont'd)
Oiemicat
Body Saction or fad Location
Reported
Expoaura
Quantity
Estimated
Estimated
Estimated
Referent, a
Formulation
Expoiuia'
Duration
Handled
Grosa Dermal
Gross
Gross
(hr)
(gallon)
Deposition" *
Reposition by
Deposition by
Quantity
Time
(pg/cm'/gal)
l^g/cm'/hrl
Cypernrwthfin <3
OiQ)
(pg/cm1)
Charier hi
iba/pal, 36%)
Hood
2.2160 3
0.6
4
0.006-1.29
0.0012-O.032
0.0094-0.26
al . 198/
Front trunk
3.99-674
0.6
4
0.003 0.63
0.0008 0.13
0 0062-J .05
Back trunk
6.07 274
0.6
4
0.004-0.21
O.OOI-O.Ob
O.OOBO.43
Forearm*
38.0-330
0.6
4
0.090-0.78
0 022 0.19
0.18-1 61
Upper arm
0.18-60
0.6
4
0.0087-0.048
0.0022-0 012
0.18 0.096
Thighs (above knee, undar apron)
4.8-188
OS
4
0.0036-0.138
0.0009-0.034
0 007-0.27
Lower laga (undar apron)
8.0-42.2
0.6
4
0.008-0.049
0.002-0.012
0 016-0.093
Sock* (inside boon)
8.1-76.6
0 6
4
0.017-0.16
0.004-0.04
0 012-0 32
glovea (undar rubber glovaa)
11.6-274
0.6
0.039-0.93
0.010-0.23
0.078-1 82
Exposure determined from aactiona ol antir* Tyvak auit. Worker*
>l*o wora ankla-langth apron* with full faca shield, coatad rubber gloves, and call-length
boota. Raaulia are rangaa of 8 utala of open lop mixing ind pumping Irom two mixer-loadera.
Each mixing/loading took no mora than 30 minutes.
Exposure* on body (action* with toft and right tidal ara combined In thi* libit (e.g.. toll and tight forearm*). Groia darmal deposition calculaiod based on
akin aurface araaa in EPA 1987a.
Paraquat (21.1%
(mg/hr)
Oig/cm*)
Chester
concintraftl
Forearm* (outaida clothing)
17.16)
N.A.
N.A.
2S.O
-
28 0
and Ward.
Thighi (outaida clothingl
14.23)
N.A.
N.A.
6.26
-
6.26
1984
Haad (axpaiedl
<
-------
OCCUPATIONAL DERMAL EXPOSURE ASSESSMENT - A REVIEW September 30, 1996
TABLE 4-6 DERMAL EXPOSURE DATA AND ESTIMATES FOR LIQUID MIXING OR TRANSFER OPERATION
(Cont'd)
Chamical
Formglalion
Body Sac lion or Pad Location
Raportad
Exposure'
Expoiura
Duration
(lul
Quantity
Handled
(gallon)
Estimated
Gross Darmal
Oaposiuon* *
Estimated
Gross
Reposition by
Quantity
Ipg/cm'/gsM
Estimated
Gioss
Deposition by
Time
(jig/cm'/hi)
Reference
Alachlor in 96%
concantrala
Forahaad and laca with EC formula!*
Cheat (outar clothing), neck and v ol rack
w/EC Chaat (Inside clothing), with EC
Back (outar clothing), with EC
Forahaad and laca with MT
Chaat (outar clothing). with MT
Chaat (inaida clothing), with MT
Maan exposure at back, outar clothing, with
MT
(P0>
0-6.33
Q-2.37
0
O-O.Q
0-7.8
0-48.8
0
0-1.47
00000000
10
10
10
10
10
10
10
10
(jig/cm1)
0-O.OOB6
0-0.0166
0
o-o.ooas
0-0.813
0-0.34
0
0-0.014
00 0009
aoooie
0
0-0.0009
0-0.0013
O-0.034
0
0-0.0014
ao.06i
ao 099
0
0-0.061
0-0.076
0-2.03
0
ao.084
Cowed ol
al.. 19tW
Oarmal exposure determined with multHayarad gauze pada. with 1 pad on chaat undar clothing. Liquid transferred with an anclosad pumping system;
aach transfer took (-10 mlnutaa. EC — EmUsjfiad Concantrata. MT " Micro-ancapaulatad. Workers wora work dothaa plua an unspacifiad protactiva
clothing. Hand axpoeura or hand protection not diacuaaad. EC tank 11 haa 4 rapHcataa, MT tank fiM haa B replicates. Exposure at chaat undar clothing
repotted aa *0". •
DEF 70 6*
Concenueta
Chaat
Back
big/cm')
0.027-0.131
0.014-0.061
1-7 hr
1-7 hr
N.A.
NA.
Org/cni'l
0.014-0.186
0.004-0.072
-
0.014-0.186
0 004 0.072
Kllgoia et
al., 1984
Flannal patch on outaida clothing aa pad. Avaraga exposure Irom 3 daya ol testing on ona mixer-loader with cloiad lystam mixing and loading. Data
(how larga variation* on hourly flux.' 1 tu. axpoaura aaaumad for groaa dermal dapoaluon.
* Dapanding on the oiiQinal data feponad. ranges with tha main valua in parenthesis; mean value ± atandaid deviation; or only the mean value (in paienthesesl is piasenied
*' Calculated by dividing paicani formulation into lha laporlad expoaute and extended for tha duiation what* appropriate; data not piovidad unless duration daia is available or assumod
4-28
-------
FIGURE 4-2 , ESTIMATED GROSS DERMiX^>EPOSITlON DURING MIXING AND
TRANSFER OF LIQUIDS
9 -
• i- • • • •
mm m • •
! =
i*i
Mead or Face
M M
IMI
•
Shoulders
•
• • © • •
1*1
9 ~
r=
6 -
5 • -
4 -
3 ~
? -
Chest
«• • • •
1 - <
l-l
•
¦ • *
1*1
M • •
¦ rr i n i n i
• •
y-me
i
Back
• • • • • •
• • • 1 •
l-l
• ¦
• • • •
l-l
• • • *
9 -
Udoct Amis
• «• • • •
9 -
i -
4 ~
1 -
Forearms
• • • • •
l-l
«
•
• • • • • w • •
• • • •
1 II 1 1
Upper Lefts
• • • • •
1*1
*
• •
• • • •
1 1 1
Lower Leas
• m •
4 '
Mill
Hands
I • •• •
•
« •• • • * ••••
1 ' ' '
i i i i 11 I I I I I II11 I 'I I I I 'I 111 I I I I I I I 11 i i I I I I i 11
0001
1 Middy. ««J.. 19(0
3 W<*cck««l. 1911
0.01 0 1 1 10 100
Gross Dermal Deposition, ug/cmA2/hr
2 DufcdmaaX«l. I9II 3 UutfanMil., I9ij 4 Niu*°<1 Sumpa, I9t)
6 Onto* Want. I9M 7. Kilmd ai. I9M f Cowdi c( *1. I9R7 9 Chafer d al. 1987
Legend: Mean +/- standard deviation | 1 Range |*| Mean * Beyond scale
4-29
-------
3CCJPAT:CNAL 3ESMAI EXPOSURE ASSESSMENT - A REVIEW
September 30, 19
-------
OCCUPATIONAL DERMAL EXPOSURE ASSESSMENT
A REVIEW
September 30, 1996
F. Intermittent Contact
Intermittent contact refers to skin exposure due to splashes
or direct contact with contaminated equipment or surfaces. Such
contact may result from wiping hands with contaminated rags,
wearing contaminated gloves, or handling contaminated tools.
There are very few studies that provide actual dermal exposure
data from such contact. One report by EPA (EPA, 1987c) presents
the results of a study.on inhalation exposure and dermal contact
to acrylamide during chemical grouting operations in sewer line
and manhole leak repairs. Dermal exposures were estimated using
absorption pads and hand washes. The study indicates that ¦
exposures were caused by contacts with contaminated equipment or
from runoff and splashes. A summary of the data is presented in
Table 4-8.
A similar study by Cummins et al. (1992) also found that
contacts with contaminated work-surfaces, equipment; and tools
were the ma.jor source of dermal exposure. Exposure at the hands
constituted the major portion of exposure. Because of pre-
existing contamination in the gloves, acrylamide loadings at the
hands determined from hand rinse often showed only a slight
increase between the post- and pre-shift (shortly after start of
work) samples. In three of the four paired tests conducted, the
pre-and post-shift samples showed total hand- contamination
changing from 30, 17, 86 /xg to 36, 20, and 90 pig, respectively;
the other pair .tested actually had a lower post-shift loading.
Surface contamination at three sites at the top of the acrylamide
mixing tank was found to be 6.2, 834, and 1348 ng per 100 cm2 of
wiped area.
A study by Maroni et al. (1981) reported dermal exposure to
polychlorinated biphenyls (PCB) in plants where PCB-containing
dielectric fluid was used to fill capacitors. Dermal contact
with PCB was believed to occur during the assembling,
handling,and testing of capacitors. The study only reported the
amount of PCB retained on worker's palms, which ranged from 2 to
28 ng/cm2 on 6 subjects. PCB contamination on workroom surfaces
and tools ranged from 0.20 to 6.17 fig/cm2 except for the surface
of a capacitor basket rolling carrier that showed a surface
contamination of 15 9 fig/cm.2. Lees et al. (1987) investigated
worker exposure to PCB during transformer maintenance and repair
operations. In addition to air samples, surface wipe and skin
wipe samples were collected to asses the potential of dermal
exposures. Geometric mean surface contamination was found to be
1.075 ng/cm2 at the work area, 0.007 jig/cm2 at an area contiguous
to the work area, 0.078 ^g/cm2 on tools and equipment, 0.006
pig/cm2 on a vehicle steering wheel, 0.018 pig/cm2 on personal
protective equipment, and 0.922 jig/cm2 per cigarette butt, and
0.008 ixg/cm2 at worker's skin (presumably the hands).
4-31
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OCCUPATIONAL DERHAL EXPOSURE ASSESSMENT - A REVIEW
September 30, 1996
TABLE 4-8 DERMAL EXPOSURE DATA AND ESTIMATES FOR INTERMITTENT CONTACT*
1 Chemical
1 Foimulation
Haponad
Exposure
(pg/cm'l
Eatimatad
Otoaa
Daiwal
ijiQfcm*)
(Eatimatad
Gross
D^poaltion by
Quantity
(jig/cm'/Bal)
Eatimatad
Grosa
Deposition fay
Tlma
(pg/em'/hr)
Raponad
Expoaura
(pg/cml
Eatlmitad
Qroaa
Darmai
Deposition
iH/cni'l
Eaumaiad
Groaa
Deposition by
Quantity
Org/cm'fgal)
Eatimatad
Groaa
Deposition by
Time
(pg/em'/tu)
Command
Reference
Shoulder
Back
1 Acrytamide
9.1%
4.4
48.4
0.74
16.7
0.646
6.99
0.092
2.07
111
EPA. 19B7c
oees
7.34
0.001
2.46
0.26
2.74
0023
0 91
12)
1.206
13.2
0.22
1.42
O.S1
6.90
0.16
0.96
(3)
0.79
8 68
0.14
0.93
0.87
7.36
0.12
0.79
(4)
0.09
0.99
0.10
0.12
0.08
0.88
0.88
0.11
161
QkmI
For»arma
1 Acrylamide
1 9.1%
33.76
371
6.7
128
0.986
10.6
0.16
3.66
111
0.10
1.10
0.0092
0.38
8.46
69.9
0.60
20.0
121
1.23
13.6
0.23
1.46
8.3
89.2
69.2
7.44
13)
0.99
10.8
0.18
1.16
0.43
4.73
4.73
0 61
(4)
o.oa
OM
0.066
0.06
0.22
2.42
2.42
0.30
(6)
Handa
Acrytamlda
9.1%
14.B
163
2.60
22.0
(1)
0.64
6.93
0.06
0.77
12)
9 02
99.1
1.86
9.72
13)
I
6 63
00.8
1.10
6.98
(4)
0 60
6.69
0.68
0.80
0.68
6.16
0.62
1.12
161
'Dermel exposure in EPA (1987c) determined lor worker* involved In grouting repair* ol sewer Una* and manholes. Exposure determined liom pads mada out of Whitman chiamatographic papar.
Hand expoaura deteimtnad from lha hand nnie technique. Hand axpotura cafcutatad liom total measured amount assuming hand aurfaca aiaa ol 820cm'.
4-32
-------
OCCUPATIONAL DERMAL EXPOSURE ASSESSMENT - A REVIEW September 30, 1996
TABLE 4-8 DERMAL EXPOSURE DATA AND ESTIMATES FOR INTERMITTENT CONTACT* (Cont'd)
(II M«an aapoiura of maintananca ar^tarvteo' fcvho fwlwimd tha grouting oparationa In a manhola. Tyvak covaraNa. hard hal, glovaa, boots, and raapuator wars worn 60 to 65 gallon* ol
compound* handled, hwtd ifrwa M 7.4 Iwa. olhar pads axpoaad 2.9 Iwa.
(21 Maan aapoaura of uNNy weitm wtw part or mad lh« grouting operation In tha manhole. Tyvak covaraia. hard hal. glovaa. boola and raaptralor were worn. 120 galtona ol compound*
handlad. hand not* ol 7.7 hn, Other pada aapoaad 3.0 Iwa.
I3| Maan expoaure ol grouting lorartten who mixed tha chemical, aaaamfclad tha equlpfnent, and oparatad tha equipment remotaly lor mainlma maintenance oparaiiona. 60 gallon* ol
compounda uaad, hand rinaa at 10.2 In, other pada aapoaad 1.3 hra.
(4) Maan expoaure ol grouting laborar who miatad tha grouting I or eaten In |3). Both tha Ipraman and laborar wore Tyvak coverall*. hard Data, boota, and glovaa. 60 gallon* ol compound*
uaad, hand rinaa at 10.2 hra, other pada aapoaad B.3 hn.
161 Maan axpoaura ol Uinrty wortac who Html tha chemlcol. aaiamtlad. and Inanlad tha equipment lor lataral Una maintananca oparation. Only atraat cloth** wara worn. 6-10 gallon* ol
compounda uaad, hand rinaa at 6.2 hra, othar pada aapoaad (.2.Iwa.
4-33
-------
OCCUPATIONAL DERMAL EXPOSURE ASSESSMENT - A REVIEW
September 30, 1996
Groth (1992) studied dermal exposure to 4,4'-methylene
dianiline (MDA) in aircraft maintenance operations through wipe
sampling of equipment and work surfaces, air sampling, and
urinalysis. The author found that removable MDA was present at
<0.004 to 1.0 ng/cm2 on all products including those considered
cured. However, the measured surface contamination did not
provide a viable indicator of the magnitude of absorbed dose from
handling MDA-contaminated materials. The author believed a more
aggressive sampling approach will be needed to yield useful data
to adequately estimate potential dermal exposure hazard.
Clapp et al. (1991) assessed various environmental exposure
measurements (air samples, surface wipes, and skin pads) to study
worker exposure (urine samples) to 4,4'-methylene bis(2-
chloroaniliAe) (MBOCA) in a cast polyurethane production
operation. Gauze pads at palms and the back of the latex gloves
worn by workers showed average total MBOCA of 4.7 to 24.6 pg/pair
of pads on mixers and 3.0 to 7. 3> /ig/pair of pads on molders and
2.3 ^g/pair of pads on a trimmer. Surface wipe samples showed
average contamination levels of 0.01 to 19.1 /xg/100 cm2 depending
on the surface sampled. The authors concluded that most exposure
occurs through direct contact and that even relatively low
surface contamination can lead to elevated urinary MBOCA levels.
Van Rooij et al. (1993) conducted a quantitative assessment
of both skin contamination and respiratory intake of polycyclic
aromatic hydrocarbons (PAHs) in coke oven workers. Based on skin
pad samples on 12 workers over five consecutive 8-hour work
shifts, average concentrations of.pyrene (as a marker compound)
on pads were 6.5 jig/cm2 at jaw/neck, 1.9 ng/cm2 at shoulders, 1.8
Mg/cm2 at upper arms, 6.4 ng/cm3 at wrist, 2.1 ^g/cma at groin,
and 2.0 /ig/cm2 at ankle. Based on these data and PAH absorption
rate constants, the authors concluded that 28 to 95% (average
75%) of the total absorbed amount of pyrene enters the body
through the skin. In another study related to exposures to PAHs,
Jongeneelen et al. (1988.) reported on the exposure of paving
workers who are exposed to coal tar derived road tars.
Contamination of the skin may result from deposition of airborne
solid and liquid particles and from direct contact with
contaminated surfaces. The end-of-shift hand washing showed a
geometric mean total hand exposure of 70 fig (pyrene) from 3 5
samples. Skin pad samples showed the wrist to have the highest
exposure with a geometric mean contamination level (pyrene) of
12.4 jj.g/cm2 from 40 samples. Significant correlations were-found
between the wrist pad or the hand wash data and the end-of-shift
urinary metabolite (1-hydroxypyrene).
' Dermal exposures at the hands and forearms to calcium
carbonate during filter press and tray drying operations were
reported in a pilot plant study by EPA (1992d) that developed
4-34
-------
OCCUPATIONAL OE3MAL EXPOSURE ASSESSMENT • A REVIEW
September 30, 1996
data on inhalation exposure, dermal exposure, and chemical
releases for use by PMN reviewers. Dermal exposures were
determined by rinsing both hands and forearms of the operator.
The measured amount of chemicals from the rinse solution were
divide'd by the total surface area of 2600 cm2 to determine unit
area deposition. The test results indicate a range of 0.039 to
0.60 mg/cm2 during filter cake removal, 0.0076 to 0.063 mg/cm2
during tray loading, and 0.0048 to 0.067 mg/cm2 during tray
unloading.
A study (Anonymous, 1996) submitted to EPA recently by a
manufacturer for PMN review has included some dermal exposure
data on trichloroketone (TCK). For the study, five process
operators and six maintenance mechanics were chosen. The study
was conducted for a full shift ranging from 6-12 hours over-one
work day. The workers were required to wear full-body cotton
underwear and cotton gloves underneath their regular work clothes
and nitrile gloves^ Workers were also required to change the
nitrile gloves every two hours, as required by EPA. Glove
permeation data for the TCK had previously- been submitted and
approved by the Agency. Both cotton and nitrile gloves worn by
workers welre collected and packaged daily. At the end of the
.work day, square sections of both coverall's and inner full-body
underwear were cut and prepared as samples to represent exposure
at various body regions. These samples were packaged,and sent to
a laboratory.
The study reported two types of dermal exposures,
unprotected and protected.. The unprotected exposure was
determined by analyzing TCK found on outer clothing, namely
coveralls and nitrile gloves. The protected exposure was
determined by measuring TCK found on inner clothing and cotton
gloves. The concentration of TCK found on a unit area of a
sample was then multiplied by the surface area corresponding to
the body region to yield- the exposure levels for a given region.
This follows the procedure used by EPA's Office of Pesticide
Programs (OPP) for assessing exposure to various regions of the
body. For the head region, where sampling was not possible, 70%
of the area was assumed to be unprotected. . This assumption was
based on the fact that hard hats and safety glasses were worn by
all workers. For the samples with non-detect or below the level
of quantification (LOQ), one-half of the LOQ was assumed to be
present for the corresponding body region. The total worker
exposure is determined by summing the exposures for each body
region and correcting with the percent field recovery. Field
fortified samples were used to estimate the percent field
recovery. The results of study are summarized in Table 4-9.
4-3 5
-------
OCCUPATICNAL OERHAL EXPOSURE ASSESSMENT - A REVIEW Septenfcer 30, 1996
TABLE 4-9 DERMAL EXPOSURE TO WORKERS IN TCK MANUFACTURING PLANT
Hand (mg/day)
Other Parts of
the Body
(mg/day)
Total (mg/day)
Average
(mg/day)
Process
Operator
Protected
0.0032-0.0074
0.0073-0.0263
0.0105-0.0337
0.0152
Unprotected
0.0027-2.422
0.0044-0.035
0.0071-2.457
0.5043
Maintenance
Mechanics
Protected
0.0024-0.200
0.0074-0.0413
0.Q098-0.2417
0.0801
Unprotected
0.0009-505.2
imj—i-i
0.0073-0.267
0.0081-505.4
163.5
The study results show that the exposures for protected
workers range from 0.010 5 mg/day to 0.03 37 mg/day for process
operators and 0.0098 to 0.2417 mg/day for the maintenance
mechanics. The unprotected workers' levels range from 0.0071
mg/day to 2.457 mg/day for process operators and 0.0081 to 505.4
mg/day for maintenance mechanics'". The results of the study show
that the dermal exposure varies widely with the worker activities
and worker habits. The range of variability for a given activity
can be quite broad between workers. In the case of maintenance
mechanics, the range of variability for unprotected exposures to
the hands is six order of magnitude. In general, maintenance
mechanics in this study were found to be potentially exposed at a
higher level than the process operators. For both maintenance
workers and process operators, the hands were found to be the
major routes of dermal exposures except for the process operators
wearing protective equipment. The protective equipment used in
this study greatly reduced exposures to TCK, especially at higher
levels of exposure..'
Dermal exposure data reported for incidental contacts as
reviewed above are all reported in terms of the chemical of
interest.¦ Only one report provided the concentration data;
calculations of gross dermal deposition for generic application
are impossible. No attempt is made here to further interpret
these data except to note that dermal exposure varies widely and
hand exposure tends to be the major contribution to total
exposure. One recent study by Popendorf et al. (1995) did report
the exposure only in terras of the formulated product
(antimicrobial pesticide) during pouring or placing of both the
solid and liquid formulations. However, only the combined total
dose from inhalation and dermal exposure (from under the clothing
and on bare skin) were provided in the report. No data were
provided on dermal deposition at various parts of the body. More
details were available on hand exposure data. The investigators
reported that during pouring and pumping of liquid, non-gloved
hands had geometric mean total' exposure of 118 mg with a
geometric standard deviation of 6.8, while the geometric mean had
4-36
-------
OCCUPATICNAL 3ERHAL EXPOSURE ASSESSMENT • A REVIEW Septentoer 30, 19
-------
OCCUPATIONAL 3E3NAI. EXPOSURE ASSESSMENT ' A REVIEW Septeflfcer 30, 1994
v. dermal exposure data from phed
A. OVERVIEW
The Pesticide Handlers Exposure Database (PHED), developed
under contract to EPA's Office of Pesticide. Programs, is a
generic database containing measured inhalation and dermal
exposure data for workers involved in the handling or application
of pesticides in the field. . The database is designed to allow
prediction of pesticide exposure during mixing/loading,
application, and flagging operations, based on any selected
combination of formulation type, mixing/loading procedure,
application equipment/procedure, clothing scenario, or other
parameters that may be relevant to exposure. It contains
exposure data generated by the EPA and pesticide registrants. In
submitting the data, each registrant is required to develop the
information following EPA guidelines and use the standard
Exposure Survey Forms for recordkeeping.
PHED also provides for certain statistical analysis of the
data. For instance, mean exposure, geometric mean exposure, or
quantile distribution from the pad or pads for a body section
under a particular operating parameter (e.g., outdoor open mixing
with an emulsifiable concentrate) with certain data quality
requirements can be easily obtained through proper subsetting of
the data parameters. Total body dermal exposure (i.e., sum of
the products of sampling pad deposition multiplied by the
corresponding body section surface area) under specific operating
parameters with specific clothing scenarios can also be obtained
through the PHED's internal statistical analysis routines..
As a database, PHED possesses certain uniformity in data
definition and QA/QC objectives. ..The dermal exposure data within
PHED thus represent a separate yet statistically more valid
database than individual studies for evaluating exposure
variables in estimating occupational related dermal exposure.
The data quality required in PHED is such that most standard
statistical analyses can be performed and'are available directly
through PHED's software. Therefore, all data derived from PHED
are presented in this chapter separate from the data from various
published reports.
• PHED VI.1 (March 1995) currently contains data on measured
exposure and- on parameters that may determine or. affect the
magnitude of exposures for over 1700 records, each record being
defined as one replicate of data representing a single worker
involved in 1 day or less of a given activity.' Each record may
include either respiratory exposure data or dermal exposure data,
or both. PHED is separated into four files: Mixer/Loader,
5-1
-------
OCCUPATIONAL dermal exposure ASSESSMENT - A REVIEW
Septetrtoer 30, 1996
Applicator, Flagger, and Mixer/Loader/Applicator. Only Che
dermal data in Mixer/Loader file were analyzed for inclusion in
this report.
B. DATA ANALYSIS PROCEDURES
1. Exposure Variables
Several important variables must be considered in analyzing
any set of pesticide dermal exposure data. In evaluating the
published studies in the previous chapter, the following factors
were included for consideration:
• Pesticide active ingredient
• Formulation type and concentration.
• Mixing and/or other work procedures
• Quantity of pesticide or active ingredient handled
• Duration of test
• Sampling pad location
• Exposure assessment method
« Clothing scenario (protective or otner clothing worn).
These factors have also been considered for PHED data input.
In addition, a data quality factor is available for
consideration. ' PHED grades the reported exposure by its quality
in terms of laboratory and field recovery data. So a user of the
database can choose only the data that meet certain quality
criteria (e.g., only analyzing those, data graded as A or B). To
obtain deposition data under specific operating and control
conditions, one needs only to define a subset of data meeting the
selection criteria, the PHED will then generate the desired
normalized exposure data through its own statistical routines.
PHED also will allow data extraction for a specific body section
or for total deposition over the entire body under various
clothing scenarios.
2. Data Normalization and Correlation
Dermal exposure sampling pad data in PHED are reported in
terms of iig/cm2 for non-hand body sections and in terms of /ig for
the hands, where available. As with other pesticide studies,
exposures are reported only for the active ingredient.
"Furthermore r-exposure-data—in- PHED -can- be - extracted_in „a
5-2
-------
occupational DERMAL exposure ASSESSMENT ¦ A REVIEW
September 30, 1996
normalized format, by quantity of AI handled, sampling time, or
AI handling rate with the data reported'as ^g/cm2/lb.AI,
ng/cnr/hr, or ^g/cm2/lb.Al/hr, respectively.
Normalized data are essential for comparing exposures
between different tests and may be useful in extrapolating
exposure if a linear relationship exists between the exposure and
the normalizing variable. This aspect was further examined using
PHED's statistical package. For this analysis,, correlation
coefficients between the exposure in ^g/cm2 and either the total
quantity of AI handled in lbs. or the sampling time in hours were
determined. The Spearman's Rank Correlation and Pearson's
Correlation coefficients were also determined using the PHED
statistical routines. The results reveal that:
® Dermal exposure at various body sections is only
slightly related to either the total quantity of AI
handled or the total test time. Only about one third
of the potentially available data sets were found to
show a significant correlation at the 95% level. (A
data set here means a set of exposure data at a body
section and the corresponding data for an independent
variable. For example, exposure data are available for
9 non-hand body sections under the open mixing arid
loading of powders packaged in bags. Testing the
correlation of this exposure data to the total lbs.AI
applied would involve '9 sets of analysis and in this
case 5 sets were found to-be-significantly correlated.)
® The number, of data sets found to have significant .
correlation are about the same for either the lb.AI or
duration variable. In other words, there is no
advantage of choosing one over the other variable to
predict exposure.
® Very high correlation coefficients are found only
between the hand exposure and either the total lbs. AI
mixed or the total hours of exposure from one operation
matrix: mixing and loading of wettable powder.
i
• Exposure at the hands may be significantly related to
the exposure at certain body sections (e.g., forearms,
thighs, and chest) but no consistent pattern is
observed among all formulation type/mixing method
matrices.
© No consistent patterns are seen from the Spearman's
Rank Correlation or the Pearson's Correlation
coefficients, implying that exposure at a specific body
5-3
-------
OCCUPATIONAL OESMAl EXPOSURE ASSESSMENT • A REVIEW
September 30, 1996
section may increase or decrease with increases in an
independent variable (lb. AI or hour).
3. Data Conversion, Data Quality, and Detection Limit
As the exposure data in PHED are reported for the AI only, a
conversion is needed to be able to interpret the exposure in
terms of estimated gross dermal deposition (i.e., the estimated
total mass of formulated product or mixed solution that is
retained in the sampling pad) as was done in Chapter IV. This
conversion calls for the reported exposure to be divided by the
weight concentration of the formulation. For a solid type
formulation, the quantity (lb.AI) normalized data from PHED can
be used directly to represent gross deposition normalized by the
amount of formulated product. This is because when converting
the lb.AI normalized data to lb. formulated product normalized
data, both the numerator (exposure) and denominator (quantity of
AI) would be divided by the same= constant, the weight
concentration of the formulation. For a liquid formulation, a
convenient normalization parameter is the volume (gallons) as has
been used in Chapter IV. Therefore, in the.data analyses for
liquid type formulations, the PHED normalized data must be
multiplied by a factor of 8..34, (assuming the. formulation weighs
the same as water which would be 8.34 lbs per gallon).
In terms of data quality, only those graded as A, B, or C in
PHED are included. At the lowest grade used, C, laboratory
recovery rate should fall between 70 and 120V with a coefficient
of variation of no less than 33%, field recovery should be 30-
120%, and the storage stability should be 50-120%. As required
under the PHED sampling protocol, dermal sampling pads are
located at the head, neck front, neck back, chest, back,
shoulder, upper arms, forearms, thigh, skin, calf., and ankle.
Hand exposures are evaluated with the hand rinse technique. For
the data extracted for this report, the average exposure is used
if more than one pad is used at a body section. Where available,
exposures outside the clothing and inside the clothing are.
extracted and processed separately. It should be noted that not
every pesticide registrant reported dermal exposure data at all
sections of the body.
In performing the statistical calculation, PHED uses one
half of the detection limit for those samples that contain non-
detectable quantity of the AI being analyzed. Also, the smallest
value reported in PHED?s statistical analysis is 0.0001 ^g/cm?
per pound of AI, this value is used in this report, where it
occurs.
5-4
-------
OCCUPATIONAL 0E3MAL EXPOSURE ASSESSMENT - A REVIEW
Sep tenter 30, 1996
C. GROSS DERMAL DEPOSITION NORMALIZED BY QUANTITY OF CHEMICALS
FOR MIXING AND LOADING OPERATIONS
Of the over 1700 PHED records, 556 records have dermal
exposure data under the Mixer/Loader file. Subsets of this data
file were developed to extract dermal exposure data under various
parameters including formulation type, mixing method, packaging
type, data grade, sampling pad location, and clothing scenario.
Within PHED, liquid formulation is classified into five types and
solid formulation is classified into 4 types. Mixing methods are
classified into 3 types. A matrix of the potential combination
of formulation and mixing method is shown in Table 5~1 to show'
which combinations contain relevant data in PHED. Packaging type
may have. an. effect on dermal exposure as it will dictate the
manual actions needed to open the package and mix the contents
with a diluent. Examining the data for all formulation types, it
appears that only the package type for wettable powder will have
a significant effect. The packaging used in other forms of
formulation tends to be of a single type (either bags or bottles)
or the difference in packaging type will have little effect on
dermal exposure, e.g., potential for dermal exposure should be.
very similar between opening-a can or a bottle and pouring the
contents into a mixing tank. Thus, only the data matrix for
wettable powder is further divided by packaging type into the bag
and soluble packet files.
Normalized dermal exposure data at various body sections
under each formulation/mixing method matrix can be processed
within PHED's statistical package to show sample size, arithmetic
mean, standard deviation, median, geometric mean, exposure values
at 10th, 25th,. 75th, and 90th percentile distribution, and the
data's variability including minimum, maximum, range, and 95%
confidence intervals. An excerpt of such data, including
arithmetic mean, standard deviation, geometric mean; and rrtedian
values, expressed as gross dermal deposition normalized by the
quantity of chemical handled is presented in Appendix A. The
type of statistical distribution of the data under each matrix as
determined in PHED is also indicated in the Appendix. For this
report, estimated gross dermal deposition at mean value and 90th
percentile distribution are used.
As described under Section B.2, the lb.AI normalized
exposure data in PHED for solid formulation is such that the data
can be used directly to represent gross deposition in terms of. ^g
of formulated product. For a liquid type formulation the PHED
data is multiplied by a constant of 8.34 to derive a gross
deposition in terms of -fig- of-formulated product per gallon of
liquid product used. The derived or converted data on gross
dermal deposition in terms of formulated product for both outside
and inside the clothing exposure are.presented in Tables 5-2
5-5
-------
OCCUPATIONAL OERML EXPOSURE ASSESSMENT • A REVIEW
September 30, 1996
through 5-9 under various combinations of formulation/packaging
types and mixing methods.
The quantity normalized gross dermal deposition as presented
here may be used to estimate total exposure if the amount of
chemical handled and operation scenario are known. However,
careful interpretation of the results is needed since deposition
is not necessarily linear to quantity and there is likely to be a
maximum loading under any situation. Such aspects are further
explored in Chapter VI where estimating for daily exposure is
discussed. The data are probably more useful in interpreting the
relative distribution of deposition at various body sections
under various operating scenarios. It should also be n
-------
0CCuP«*::ml hxposuse assessment a review
Seocenrwr 30, 'W6
TABLE 5-1
A MATRIX OF FORMULATION TYPE AND MIXING METHOD AS
CLASSIFIED IN PHED
¦ Liquid Code
Mixing Method
1
2
3
l
/
~
2
/
3
/~
4
/
5
Mixing Method
Solid Code
1
2
3
IB and IP
/
2
/
3
I 4
/
/ wfcart raltvant data art availabla froa NO.
* Only haa two data points for tiw body taction aaaaurad; axcludad frm this analysis.
Liquid Coda*
1 ¦ EajlsiflabU eoncantrata
2 ¦ turnout suaparalon
3 ¦ Nfcroancapaulatad
4 ¦ Solution
5 ¦ Undllutad liquid
Solid Codas
11 • uattabl* pointer in bags
1P ¦ VattaMa poNdar In aoltirt* pacfcats
2 ¦ OryfloMabla
3 ¦ Oust
4 ¦ Oramia
Mixing Nathod Codas
1 «'0pan
2 ¦ Cldaad, asdwitcal piap
3 « Cloaad, gravity faad
5-7
-------
xr-ptr::*al :£wl exposure assessment • * review
Seotenwr 30,
TABLE 5-2
Estimated Gross Dermal Deposition Normalized by Quantity of
Chemical Handled (jxg/cmVgal) from PHED for
Emulsifiable Concentrate (Liquid Code l) with
Open Mixing (Mixing Code 1)
iody Section
•katoar of Miaiur—ntl
Eatlaatad
Eatlaatad 90th
M««n Qapoaitfon*
Pareartila Oaooaicfon
OUTS IOC aOTHIW
h«#d
77
0.0817
0.2152
nmck front
23
0.0717
0.1476
nack back
13
0.0899/0.0300
0.0809
thouldar
81
0.0399
0.1076
ir*
IS
0.0M7
0.1789
cheat
80
0.07*7
0.1501
back
93
0.0267
0.1076
fomrm
109
0.8291/0.0342
0.7890
thiih
64
7.B29/0.0400
1.3261
tdtn
14
0.9129/0.0090
0.0217
calf
22
0.4449
0.9491
ankla
43
1.7009/0.0447
0.4149
hands
24
141.09
471.7
1
1
ML O0TH1H
haad
*
0.0000
0.0017
nack front
0
nack back
0
shoulder
2i
0.0025
0.0090
19
2.5837/0.0000
0.0033
chaat
96
0.0409
0.1076
back
82
0.0229
0.1078
foraarw
64
0.0499
0.1076
tMgh
40
0.0947
0.1776
ahfn
0
calf
22
0.0090
0.0090
ankla
32
0.3244/0.0017
0.0317
handa
0.7411
2.149
• Excapt in 3ati tats *(tn larfa variation* whara both ttia aatfaatad
nadlan (tha aacord valua showi) dapoaltlona ar* praaantad.
5-3
(tfM flrtt valua tltovn) wd tna
-------
:cr-p*":N*L :e?wl -xpcsure *ssessxcnt a review
5eptent5«r JO,
TABLE 5-3
Estimated Gross Dermal Deposition Normalized by Quantity of
Chemical Handled (jig/cmVgal) from PHED for
Emulsifiable Concentrate (Liquid Code l) with
Closed Mixing (Mixing Code 2)
Body Section
Muter of HaaauraMRts
Eatlmtad
Haan Oapoaition*
Sstiwetad 90th
Pareantila Oaposicion
OUTSIDE CLOTHING
h«ad
20
0.0117
0.0392
nack front
0
naek back
0
jhouldar
4
0.0025
0.0058
upper ana
13
0.0047
0.0092
efcMt
20
0.0275
0.0542
back
20
0.Q19O
0.0417
for«tm
14
0.1735
0.2043
(Hi 01
14
o.svvr
0.5473
idin
8
0.0S9O
0.100*
calf
0
ankla
J
0.0142
0.0325
hands
0
116IOC PERSONAL CL0TMIH
haad
0
nack frsnt
0
naek beck
0
ihouldar
0
43P*r ana
If
9.0025
0.0042
ehaot
14
0.0017
0.0042
back
14
o.oorr
0.0042
feraaraa
If
0.0017
0.0042
thfah
14
0.4262/0.0033
0.0042
»h
-------
xr„Ptr;;xAL :s?>ui ixPOSWE iSSESSWKT • * *EVtEV
Seo:»me«r 30, 'W$
TABLE 5-4
Estimated Gross Dermal Deposition Normalized by Quantity of
Chemical Handled (fig/cm2/gal) from PHED for
Aqueous Suspension (Liquid Code 2) with
Open Mixing (Mixing Code 1)
Sody Section
iMtoar of Naaauraaantt
Estimated
Maan Saoaairlon*
Fitiaated 90th
Percentile Depoeition
arrsroe clothing
h#ad
15
0.1668/0.0100
0.0554
naek front
0
nack back
0
shoulder
16
0.0292
0.0323
upp«r im
4
0.0083
0.0142
ChMt
16
0.5900/0.0040
0.2919
back
16
0.0200
0.0442
foraarw
6
0.0934
0.1774
th<«h
14
0.49T1
1.1047
iA
-------
xr.p*": >al !
-------
xrjP»r::*iL hxpcsijRs assessment • a review
SeotMBar JO, '994
TABLE 5-6
Estimated Gross Dermal Deposition Normalized by Quantity of
Chemical Handled (^g/cma/lb) from PHED for
Wettable Powder in Bags (Solid Code IB) with
Open Mixing (Mixing Code l)
Sody Section
feaear of Naaauraaants
EttfMtad
Estiaatad 90th
ffaan Oapoaitfon*
Pareartfta Oapoaition
QUT3IDC CLOTHING
hatd
10
0.039
0.075
rwck front
0
rack back
0
thou Idar
0.2062
0.4742
lopar *r*a
0
CTIMt
14
0.1322
0.2143
back
16
0.0AM
0.1323
foraarva
0.9214
1.7603
tAfgh
16
0.39*8
0.J127
•hln
4
o.oan
0.1734
calf
0
anfcla
4
0.04M
O.OflSO
handi
7
11.991
53.21
inside reea
ML CLOTH D®
haad
a
nack front
0
POCK D9CI
0
ihoul dar
11
0.1962
0.1602
n»* •<*
0
efcaat
10
0.1399/0.000
0.0133
back
10
0.14J7
0.1723
foraaraa
13
0.099S
0.124
thigh
9
0.0097
0.013
•Mn
4
0.00S7
0.0065
0
arid a
4
o.ooa
0.0013
8
0.04M
0.0977
nodi an (tha »»eand valua thown) dapoaitiora ara praaartad.
5-12
-------
xr_p*r::nai. ;e*Mi ;x?oslre *ssEss*enr ¦ a «eviev
Seoti
«r 30, "X*
TAJLE 5-7
Estimated Gross Dermal Deposition Normalized by Quantity of
Chemical Handled (Mg/cmJ/lb) from PHED for
Wettable Powder in Packets (Solid Code IP) with
Open Mixing (Mixing Code 1)
ledy Section
>fcj*ar of w«esursa«nti
Estfaattd
Estiaatad 90th
Naan Oapoaltion*
Pvrcjrrcila Oapoaition
0UT3I0C curmiw
h«ad
15
o.oojr
o.owa
nock front
3
0.0009
0.0014
rack back
6
0.0004
a.0004
shouldtr
&
0.0013
9.0020
LCP9T ir*a
ettaat
15
o.oba
0.0096
back
15
0.002*
0.0098
foraaros
15
0.0072
0.0090
tMflh
15
0.0211
o.ooos
•Mn .
3
0.000*
0.0008
ealf
6
0.0032
O.OOtt
«*la
3
0.0011
0.0023
hwvto
S
0.0265
0.0557
insik rasa
MlOOTXItt
haad
6
O.OOOf
0.0010
nack front
0
nack back
0
shoulder
6
0.000*
0.0010
uppar arai
0
chaat
12
0.0005
0.0010
back
12
0.0009
0.0010
foraarm
«
0.000*
0.0010
thigh
12
0.0013
a.0010
shin
3
0.0001
0.0001
erif
t
O.OOOf
0.0010
anklt
3
0.0001
0.0001
6
0.0001
0.0001
(ttw ffr«t valua draw) «nd tna
nadfan (ttia iKond vatua tironn)
ttlona *rt praaantarf.
5-13
-------
:cr_p»r::mi ;e5>ui =.t?csLiRE ass£ss*€*i' ¦ * review
S«otenc«r 30, ">9i
TABLE 5-8
Estimated Gross Dermal Deposition Normalized by Quantity of
Chemical Handled (^g/cm3/lb) from PHED for
Flowable Powder (Solid Code 2) with
Open Mixing (fixing Code l)
Body Section
faatoar of NeaauraMnt*
Esttaatad
Mean Oaooaftfon*
Estfaatad 90th
Pareantila Oapoaltion
OUTSIDE CLOTHING
haad
21
3.0118
0.0261
rwek front
0
nKk back
8
9.0006
0.0013
ihoul^ar
0
WOT ana
16
3.0393
0.W33
chaat
16
0.0927
0.2004
back
16
3.0394
0.1195
for—rm
24
o.ont
0.2127
thigh
16
9.42(0
i.aaat
ahin
16
0.0344
0.074
calf
0
ankla
0
harda
0
INSIDE PCRSOML CUJTXI*
haad
0
nack front
a
rtaek back
0
ahouldar
0
uppar
14
3.0024
0.0021
cheat
24
0.001S
0.00*2
back
24
0.0011
0.0020
foraaraa
14
0.0029
0.00(9
tMah
24
o.oasi
0.0410
thin
14
0.0114
0.0181
| calf
0
1 ankta
a
o.ooos
0.3004
25
.9.0094
0.0174
* Exeapt in data *at> with larga variations tfiara both
madian (tha sacond value ihOMT) dapoaltlona arc praaarr
tad.
5-14
-------
:cr-P<" :e?ml -xpcslse *ssess*cxt • « jeviev
'«t«nr 30, '996
TABLE 5-9
Estimated Gross Dermal Deposition Normalized by Quantity of
Chemical Handled (/j.g/cmJ/lb) from PHED for
Granule (Solid Code 4) with
Open Mixing (Mixing Code 1)
Body Section
feafear of Waiurawarti
Estfwtad
W«an OapMftton?
EttiMCad 90th
Ptrearrtfl* Oapoaitior
OUTSIDE aOTWW
fitad
3
0.0011
0.0021
nack front
0
rwck back
0
ihouldar
11
0.0039
0.0067
Looor im
3
0.0014
0.003
CftMt
11
0.0034
0.004
tack
11
0.000*
o.ooot
foraanaa
11
0.0099/9.0021
0.0061
thfah
11
a.azn/o.ossB
0.0240
thin
0
calf
0
•nfcla
3
o.osm
0.0671
hvwto
0
INS IOC KJtSO
DM. CL0TH1M
h««d
0
rwck front
0
ntck hack
0
shouldar
0
upper «r*a
3
0.0001
0.0003
dint
1
o.aoos
0.0008
back
s
0.0004
o.ooo*
fortaraa
3
0.0007
0.0014
thigh
0
ihin
0
eal f
0
ink I a
3
o.ooas
0.0007
harda_.
3
0.0033
0.006S
^xSp?TT^^^»trT?tTt«r9«T!n«fo5r,3i5f5ToStR!l^tTS?3?^S7SJTfpr^in3^35^r7tftr
madian (tha itcond vtlua thowU dapoaitlora art prwantad.
5-15
-------
:cr_p*r:cNAi ;e*hai. ^xpcsure assessment ¦ * review
ieocemc«r 30, '996
D. 3RCS3 DERMAL DEPOSITION NORMALIZED BY" EXPOSURE DURATION
FCR MIXING AND LOADING OPERATIONS
PHED_also permits normalization of dermal exposure data by
the duration of exposure or sampling test, with the data reported
as jig.AI/cmVhr. To convert the AI based data to a formulated
product based data, i.e., to derive estimated gross dermal
deposition data, data from PHED must be divided by a weight
concentration of the AI in formulated product. However, weight
concentration of the AI in formulated product varies from test to
test. To estimate any statistical parameters on gross dermal
deposition, it would have been necessary first' to convert the
measured raw data in each record to a gross dermal deposition
format then to perform the statistical analysis. However, the
PHED statistical package does not allow conversion of the raw
data before statistical calculations.
Instead of creating a new database for statistical analysis,
a simpler approach was used to utilize the statistical data
already available from PHED. With this approach, certain single
values from weight concentration distribution data were selected
to convert statistical parameters available from PHED into gross
dermal deposition data. As used in presenting the quantity
normalized data, the mean exposure and the 90th percentile
exposure will also be used here. To derive these estimates for
time normalized data, two concentration levels were selected:
the mean concentration of AI under each formulation type/mixing
method matrix for converting the mean exposure, and the 10th
percentile concentration to convert the 90th percentile exposure
to estimated gross dermal deposition. Statistical distribution
of the weight concentrations for various matrices of formulation
type and mixing method as derived from PHED are shown in Table 5-
10. The time normalized gross dermal deposition estimates as
calculated for various matrices- are shown in Tables 5-11 through
5-18.
The time normalized' data may be used to estimate total
dermal deposition expected at the end of a certain period of
exposure. Obviously/ there is a limit on how far this
extrapolation can be used because of questions on linear
relationship and maximum loading. Further discussion of this is
presented in Chapter VI. It should also be noted, as in the case
of quantity normalized data, that in some data sets, the mean
value is greater than the 90th percentile estimate because of the
wide range of data variation. In such cases, the median
estimates are also indicated.
5-16
-------
xrjP*r:ON*L SEXUAL EXPOSURE ASSESS**! ¦ A JEYIEV SecEemcwr 30, -994
TABLE 5-10
Distribution o£ Weight Concentration of AI in Formulation
Fomulation/HUing
Matrix
Xuifcar of Fiald
Test!
10th Parcantila
Concantration
Maan
Concantr»tion
90th Parcantila
Concantrition
Eirtjtsifiable
eoncantnte with opan
mixing
134
1.3 Iba/gal
4.25 Iba/gal
80 Iba/gal
Edlillif labia
concentration wi th
elosad Mixing
21
2 Iba/gal
3.24 Iba/gal
4 Iba/gal
Aquaoua tuapanafon with
open nixing
17
4.17 Iba/gal
4.16 Iba/gal
4.17 Iba/gal
Solution with opan
mixing
27
2 Iba/gal
3.09 Iba/gal
8 Iba/gal
Wottabla powdar in bags
with opan aixing
35
50%
6A.06X
80*
Wattable powdar in
packata with opan
¦ixing
12
40X
45X
5 OX
Flowafcla powdar with
opan aixlng
26
SOX
63.44*
8SX
Grarula Mi til opan
¦ixing
U
its
io.m
13.5X
5-17
-------
OCCIPUT: :E5M4L :
-------
:cr.P»-;:>m. :.x?csure assessment • * review
Sect
r 30. '996
TABLE 5-12
Estimated Gross Dermal Deposition Normalized by Time
(lug/cmI/hr) from PHED for
Emulsifiable Concentrate (Liquid Code l) with
8c*#y Section
Kufcer of Nessureaams
Estimated
Mean Deposit ion*
Estimated 90th
Percentile Deposition
OtfSIDE CLOTHIMS
ne*d
20
0.4474
3.439
neck front
0
neck beck
0
shoulder
4
0.3604
1.380
upper *rm
13
0.5725
0.8434
chest
20
1.9548
2.9807
back
20
1.43M/0.0134
0.3411
forearm
14
1.3604
5.087
thfgh
H
4.4519/0.5115
5.409
Kiln
8
0.0420
0.3092
calf
0
ankla
5
1.4451
5.203
hands
0
INSIDE PERSONAL CLOWNS
head
0
neck front
0
neck beck
0
shouldsr
0
upper irm
19
0.0T57
0.2014
cheat
14
0.0049
0.0100
back
14
0.0044
0.0100
foreeraa
19
0.0423
0.Z319
thfjh
14
27.056/0.0059
0.0780
shin
a
0.0059
0.0104
calf
0
inkle
ii
0.1511
0.3194
hands
15
0.1197
0.4915
* Except in data sets with
larfa variation* Mfiere bott)
the estiaated aaan (the first value show) and the
median (the second value show) depoaftfona are presented.
5-19
-------
3cr_'P*ric«*L i£?mal -:k?osur£ assessment - a review
Seoteirw 30, 'Wa
TABLE 5-13
Estimated Gross Dermal Deposition Normalized by Time
(/xg/cmVhr) from PHED for
Aqueous Suspension (Liquid Code 2) with
Body Sactfon
Muter of M«asur«antt
Estiaatid
Naan Oapoaition*
. EitiMtad 90th
Parcantfla Oapoaition
OUTSIDE CLOTHING
head
15
2.7376
J.215
neck front
0
rack back
0
jhouldar
16
1.6373/0.4056
1.626
i*par
6
0.1111
0.2118
ehatt
16
29.166/0.7839
15.90
back
16
1.1407
2.600
foraaraa
6
1.10M
2.157
thigh
16
19.825
28.40
thin
10
318.58/42.53
272.06
calf
0
ankla
6
1.1949
2.921
handa
16
180.55
444.27
116 IOC PdtSOWL OUTH1NB
haad
0
rtack front
0
nack back
0
sheuldar
0
i*par araa
0
chast
0.063*.
0.1234
back
6
0.0327
. 0.044
foraanaa
6
0.0922
0.1842
thfgh
0
thfn
6
0.1185
0.2178
calf
0
arttla
6
0.0527
0.0918.
6
13.349
23.11
rndian
-------
:cCwP*r::»ui =
-------
x:-_p* :e?M4L e
-------
:cz*pat::hal :e?wL :'
-------
ccr-p*r::M(. :ewl :*pcsu«s *ssEssw
0
INS IK PERSON. OOTXIW
head
0
neck front
0
neck back
0
shouldar
0
t«par araa
•16
0.0038
0.0076
chest
26
0.0200
0.0918
back
26
0.0055
0.0136
forearm
1*
0.0OU
0.0066
thigh
24
0.0972
0.1096
thin
16
0.0214
0.0396
calf
0
anklt
S
0.0409
0.1256
25
0.0979
0.4069
* Except in data tats with,
larfe variation* iriiera both
median (the second value ihoin)
It for* ara presented.
5-24
-------
scrjPAT::NAL :e?kal :.xposlre assesshent • a keview
Swcenx**- 30.
TABLE 5-18
Estimated Gross Dermal Deposition Normalized by Time
(/ig/cmVhr) from PHED for
Granule (Solid Code 4) with
Sody Section
ttiabtr of KmauraMnts
Estimated
H«*n Depoaition"
fstiimad 90th
Parctnti(• Oapositior I
0UT5IDE CLOTHING |
h#»d
3
2.6672
4.121
neck front
0
n«ck back
0
shoulder
11
1.6256
12.16
i£par im
3
5.1362
7.«0
ehtst
11
11.327
14.28
back
11
0.8337
2.029
forearm
11
17.239
58.68
thigh
1t
300.80/7.11
39.27
shin
a
calf
a
ankla
3
39.20
91.99
hando
0
INS IOC PCRS0MM. dOTHIW
haad
0
r*ek front
0
rttck b«ck
0
ihoutdtr
0
LBP«r inw
3
0.2164
0.276
cheat
8
0.9599.
1.576
back
8
0.7638
1.54
for«ar*a
3
1.6317
2.981
thigh
0
shin
0
calf
0
«nkl#
3
0.4127
0.64
hards
3
2.66*2
5.476
mdian (th« socond v«lu« shew) dapoaitiona ar« prwantad.
5-25
-------
OCCUPATIONAL 3ESMAI EXPOSURE ASSESSMENT - A REVIEW Septenfcer 30, ;
-------
JCCUPAT[CNAL OERMAL EXPOSURE ASSESSMENT - A REVIEW
September 30, 1996
TABLE 6-1
90TH PERCENTILE ESTIMATE OF POTENTIAL GROSS DERMAL DEPOSITION
NORMALIZED BY TIME (^g/cm2/hr) FROM TWO DATA SOURCES
Open Mining of
Emulsifiable
Concentrate
Closed Mixing of
Emulsifiable
Concentrate
wjii ¦» ft II - ==
Open Mixing of
Aqueous Suspension
Open Mixing of
Solution
Literature
PHED
Li terature
PHED
Literature
. PHED
Literature
PHED
Head
0.1
1.20
0.07
3.60
--
3.20
J.30.
Meek Front
..
2.60
..
Neck Back
a m
0.K
..
Shootder
3.0
0.97
1.40
..
1.60
2,10
Upp«r Arms
0.1
37.0
0.86
0.21
1.10
Cheat
8.0
3.30
1.0
3.00
..
16.0
9.10
Sack
3.0
0.89
0.2
0.34
..
2.60
1.50
Forearms
10
10.0
5.0
2.20
13.00
Thigh
5.0
59
5.0
..
28.0
. 7.40
Shin
¦ 1.0
1.80
0.30
27.0
..
Calf
17
6.60
Ankle
13
5.20
..
2.90
88.00
Hands
200 .
5,200
-*
UQ
120
6-2
-------
0CC'uP4T!;nAI OESHAL EXPOSURE ASSESSMENT - A REVIEW
September 30, 1996
TABLE 6-1 (Cont'd)
SUMMARY OF 90TH PERCENTILE ESTIMATE OF POTENTIAL GROSS DERMAL
DEPOSITION NORMALIZED BY TIME (Mg/cm2/hr) FROM TWO DATA SOURCES
Mixing of Uettable
Powder (in bags) to
Liquid
Mixing of Uettable
Powder (in packets)
to Liquid
Mixing of Flowable
Powder to Liquid
Mixing of Granules
Li terature
PHE0
Literature
PHED
Literature
PHED
Li terature
PHED
Head
120
2.10
..
0.49
0.18
4.0
Meek Front
• •
--
0.06
» m
Neck Back
..
0.03
0.23
Shoulder
30
27
0.015
12.0
Upper Arm*
O.S
--
--
0.20
7.30
Cheat
AO
29
0.49
0.38
14
Back
15
26
0.49
0.27
2.0
Forearm
200
59
0.54
1.40
59
Thigh
15
23
2.90
4.10
39
Shin
0.1
S.O
0.026
0.16
..
Calf
..
..
0.07
~
Ankle
0.14
0.094 '
92
Hands
300
420
2.Z0
--
--
I
6-3
-------
OCCUPATIONAL DERMAL EXPOSURE ASSESSMENT - A REVIEW
September 30, 1996
TABLE 6-2
SUMMARY OF 90TH PERCENTILE ESTIMATES OF POTENTIAL GROSS DERMAL
DEPOSITION NORMALIZED BY QUANTITY OF
CHEMICAL HANDLED (^g/cm2/gal or fig/cm'/lb) FROM TWO DATA SOURCES
Open Mixing of
Emulsi fiable
Concentrate
Closed Mixing of
Emultifiable
Concentrate
Open Mixing of
Aqueous Suspension
Open Mixing of
Solution
Literature
PHED
Li terature
PHE0
Literature
PHED
Literature
PHED
Head
0.4
0.22
0.039
0.058
0.074
Neclc Front
0.15
..
Neck Back
..
0.081
..
..
Shoulder
0.3
0.11
0.0058
0.033
0.063
Upper Arms
0.01
0.18
0.0092
0.014
0.010
Chest
0.4
0.15
0.054
0.29
0.25
Back
0.2
0.11
0.042
O.U
0.038
Forean*
4.0
0.79
0.20
0.18
0.14
Thigh
10
1.30
0.85
1.10
0.21
Shin
2.0
0.022
0.10
5.60
Calf
• m
0.95
0.013
Ankle
0.41
0.03
0.20
..
14
Honda
100
470
••
33
--
0.30
All initt art in (/g/aafygal.
6-4
-------
OCCUPATIONAL OESHAl EXPOSURE ASSESSMENT - A REVIEW
September 30, 1996
TABLE 6-2 (Cont'd)
SUMMARY OF 90TH PERCENTILE ESTIMATES OF POTENTIAL GROSS DERMAL
DEPOSITION NORMALIZED BY QUANTITY OF
CHEMICAL HANDLED (jig/cm2/gal or ^g/cm2/lb) FROM TWO DATA SOURCES
Mixing of Wet table
Powder (in bag*) to
Liqufd
Mixing of Uettablt
Powder (in packets)
to Liquid
Mixing of Flowabl*
Powder to Liquid
Mixing of Granules
Li terature
PHED
Literature
PHED
Li terature
PHED
Literature
PHED
Head
0.4
0.075
0.0098
0.026
0.0021
Meek Front
0.0014
..
..
Heck Sack
0.0006
0.0013
Shoulder
0.47
0.002
0.0067
Upper Arms
0.6
0.093
0.003
Cheat
1.0
0.21
0.0098
0.20
0.006
Back
0.1S
0.13
0.0098
0.12
0.0008
Foreanw
2.0
1.80
0.0098
0.21
0.0061
Thigh
3.0
0.S1
0.081
1.90
0.026
Shin
0.1
0.18
O.OOOS
0.08
Calf
0.0066
--
--
Ankle
0.035
0.0023
0.0671
Hands
1.5
53
0.056
--
--
All units art in yg/caVlb.
6-5
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OCCUPATIONAL DERMAL EXPOSURE ASSESSMENT - A REVIEW
September 30, 1996
exposure time, there is no particularly appropriate duration
based on a review of the literature for extension o£ the time
normalized data. For pesticide mixing and loading operations,
most of the studies cited in this document used a sampling time
of no more than 60 minutes. Some investigators then extrapolated
the measured exposure to a selected duration for an estimate of
daily exposure. For example, Maddy et al. (1980) used a 2-hour
time to calculate daily exposure. Others believed extrapolation
of short duration measurement to a daily exposure was
inappropriate and measured the exposure for the entire work day
(Knarr et al., 1985). Most of the mixing and loading operations
reported in PHED show an average sampling time of 0.30 to 2.8
hours among various formulation type and mixing method matrices.
For this document, a 4-hour duration is chosen for extending the
time normalized data. This is based on the observation that
workers typically take a meal break, perhaps with some washing
activities, in the middle of an 8-hour work shift.
As for the quantity of chemical handled per day, there is
even less data available. In most published reports, the
quantity of Al or formulated products handled is often not
reported. In PHED, the data on total quantity of Al mixed is
available thus permitting calculations of a total quantity of the
formulated product used in each test. Table 6-3 presents a
selected quantile distribution of the data on tot;al quantity of
pesticide product used in each matrix of formulation type and
mixing method. A-wide variation, is seen between different
matrices. There is no information on how such data relate to
industrial operations. As a preliminary estimate of daily
exposure, the 90th percentile quantity of the formulated product
reported in PHED is used in this document to extend the quantity
normalized data, assuming that larger quantities are more often
handled in industrial operations.
Data from PHED, as shown in Tables 6-1 and 6-2, ate grouped
by pesticide formulation type and mixing method. Such grouping
may not always be analogous to industrial operations. An
industrial mixing operation often is designed to mix or provide
contact between mutually insoluble liquids, between liquids and
solids, or between solids. Contrary .to pesticide mixing and
loading operation, for example, not many industrial mixing
operations involve dilution of an emulsifiable concentrate. Of
the four liquid formulation types, only the mixing of aqueous
suspension and solution may be considered as closer to some
equivalent' industrial operations. For the mixing of solids,
mixing wettable powder in bags into slurries and dry mixing of
granule may_find some equivalent operations in industries.
Therefore, only the"" data Tor thes"e"" "four Operations " are -extended
to estimate daily exposure. The extended data, defined as Daily
Potential Gross Dermal Retention, are presented in Table 6-4,
6-6
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OCCUPATIONAL OERMAl EXPOSURE ASSESSMENT
A REVIEW
Septeroer 30, 1996
TABLE 6-3
DISTRIBUTION OF THE QUANTITY OF
FORMULATED PESTICIDE HANDLED IN PHED
Formulation Type and Mixing
Method
Mean and Quantile Distribution
N
Mean
50th Percentile
90th Percentile
Emulsifiable concentrate
with open mixing
5.01 gallons
1.42 gallons
9.S2 gallons
136
Emulsifiable concentrate
with closed mixing
S2.10 gallons
10.0 gallons
175 gallons
22
Aqueous suspension with
open mixing
31.9 gallons
27.5 gallons
42.5 gallons
17
Solution with open mixing
2.84 gallons
1.2S gallons
4.0 gallons
27
Wettable powder (in bags)
with op*n mixing
74.6 lbs
'50 lbs
159 lbs
35
Uettable powder (in
pockets) with open mixing
8.79 Ibe
7.75 I be
18 lbs
12
Ory flowable powder with
open mixing
29.90 Ibe
11.8 lbs
74.8 Ibe
26
Granule with open Mixing
3871 Ibe
4020 lbs
9110 Ibe
14
6-7
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OCCUPATIONAL DERMAL EXPOSURE ASSESSMENT - A REV1EU
September 30, 1996
TABLE 6-4
ESTIMATED DAILY POTENTIAL GROSS DERMAL RETENTION
(outside clothing) IN ng/cm*
1 Body Section
Agiieoua Suapenaiart/Open
Mixing
Solution/Open Nixing
Wettable Powder (bags)/0pen
Nixing
Granule/Open Mixing
¦y
Time
By
Quantity
N
By
Tiae
By
Quantity
N
By
Time
By
Quantity
N
By
Tiae
By
Quantity
H
H Head/Face
12.8
2.47
15
13.20
0.30
23
8.40
11.9
10
16.0
19.1
3
Shoulder
6.4
1.40
16
8.40
0.25
16
108
74.7
13
48.0
61
11
Upper Arm
0.84
0.60
6
4.40
0.04
16
--
0
31.2
27.3
3
Cheat
64
12.3
16
36.4
1.0
23
116
3.34
16
56
54.7
11
Back
10.40
1.87
16
6.0
0.15
23
104
20.7
16
8.0
7.29
11
Forearms
8.80
7.65
6
52.0
0.56
23
236
286
18
236
55.7
11
Thigh
112
46.8
16
29.6
0.81
23
92
81.1
16
156
23.7
11
Shin
1080
238
10
0
32
28.6
4
--
--
0
Calf
0
26.4
0.052
7
..
0
--
0
1 Ankle
11.6
8.50
6
352
56.0
16
0.56
13.5
4
368
611
3
| Hands
1,760
1,403
16
480
1.2
6
1,680
8,427
7
--
--
0
Note: 1. Time normal I zod gross dermal deposition data are extended by a duration of 4 hour* to derive tiap normal i zed daily potential
retention.
2. Quantity normalized groat deraol deposition data are extended by 42.5 gallons for aqueous suspension; 40.0 gallons for solution; 159
lbs for wettable powder; and 9110 lbs for granule to derive quantity normalized potential retention.
3. Ns Niafcer of aeasureaenta.
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OCCUPATIONAL DERMAL EXPOSURE ASSESSMENT
A REVIEW
September 30, 1996
with the time and quantity based data listed side by side for
comparison. As discussed earlier, a 4-hour duration is used for
extension of time normalized data and the 90th percentile
quantity under each applicable matrix of formulation type and
mixing method is used for extending the quantity normalized data.
The number of measurements for each body section under each
scenario is also indicated in the table to show the relative
strength of each estimated retention rate.
As expected, the data presented in Table 6-4 shows that the
hands generally have the highest estimated gross dermal retention
among all body sections. The next highest retention is generally
found at the forearms, chest, or thigh. These are all body
sections more likely to come into direct contact with the
chemical during mixing and loading operations. Within each
formulation type/mixing method matrix, one or two body sections
may be found to have an extraordinary high retention as compared
to other body regions. For example, a retention of 56 ^g/cm2/lb.
is found at the ankle as compared to no greater than 1.2
fig/cm2/lb. for other parts of the body for open .mixing of
solutions. Further examination of the data often reveals the
presence of one or two unusually high exposures among all tests
reported for that body section which would have biased the data
toward the high end.
Comparing between the time and quantity extended data, the
time based data always has a higher value for each body section
than the quantity based data, with a few exceptions. It would
appear that the time based data would provide a more conservative
estimate of gross dermal retention.
C. COMPARISON WITH CEB •METHOD PARAMETERS
In reference to the. input parameters used in the CEB method,
only the retention at the hands can be directly compared to the
available PHED data. The CEB method uses 1 to 3 mg/cm2 for hand
exposure during various liquid mixing and solid handling
operations. The PHED data generates an estimate of 0.5 mg/cm2
(open mixing of solution) to 1.8 mg/cm2 (open mixing of aqueous
suspension).
A comparison of the CEB method "Q" values with the
equivalent PHED based data is provided in Table 6-5. Due to a
lack of data, not all work activities covered by the CEB method
can be addressed here. In Table 6-5, the activities implied for
any specific formulation type/mixing method were interpreted
liberally~so that there would -be more-equivalent data for
comparison. Specifically:
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OCCUPATIONAL OESHAL EXPOSURE ASSESSMENT - A REVIEW
September JO, 1994
TABLE 6-5
EQUIVALENT "Q" VALUE FOR HAND EXPOSURE
FROM CEB METHOD AND MONITORING DATA
Typical Work Activities Grouped
by CEB
CEB Value
(mg/cm2)
Monitoring
Data* (rag/cm2)
Handling wet surfaces
{immersion)
5-14
Filling, dumping containers of
powder, flakes, granules
1-3
1.7"
Spray painting
1-3
. Maintenance/manual cleaning of
equipment
1-3
Unloading filter cake
1-3
0.039-0.6e¦
Changing filter
1-3
Filling drums with liquid
1-3
0.5-1.8b
Connecting transfer line
1-3
Weighing powder/scooping/mixing
1-3
1. 7*
Sampling
1-3 .
Ladling liquid/bench scale
liquid transfer
1-3
0.5-1.8"
PHED data expressed as 90th percentile estimated exposure
with 4-hrs of exposure using time normalized data, except
otherwise noted
Considered to be represented by open mixing of wettable
powder
Considered to be represented by open mixing of aqueous
suspension or solution
Data from EPA 1992d.
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OCCUPATIONAL 3E3MAL EXPOSURE ASSESSMENT - A REVIEW
September 30, I9
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OCCUPATIONAL 9E3HAL EXPOSURE ASSESSMENT • A REVIEW
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these factors. Extrapolation of the normalized data by
any factor is necessary for estimating exposure in
industrial operations but will introduce additional
uncertainty.
o Varying field conditions, such as wind speed and
relative humidity, will affect the amount of splash or
spray droplets that may impinge and.retain on an
operator's skin or clothing.
• Retention rate on absorbent pads may be higher than the
actual retention rate on smooth skin surface.
Conceivably some droplets, when impinged on the skin
may quickly drip off the surface of the skin but would
be absorbed on the pad. The use of retention rates on
pads could thus result in an overestimate of exposure.
On the other hand, deposition or absorption at certain
parts of the body may-be overlooked. In most dermal
exposure studies, it is assumed that no absorption
through the hair will take place, but materials
deposited on or applied to the hair may also come in
contact with the skin. Some investigators have taken
this into account. For example, Rodricks and Tumbull
(1983) assumed a maximum of 2% of material applied to
the hair will be in contact with the skin and available
for absorption in their study of risk assessment from
skin penetration data.
• Several types of surrogate skins have been used as
samplers for dermal exposure, and results may not
always be comparable. Even if only absorbent pads were
used for sampling, variations in material,
construction, location, handling, etc., can cause
differences in analysis results.
e Duration of test varies among the' studies. The results
from a shorter duration test will have a higher
variability than a longer duration test. One reason is
that the effect of time-weighted averaging will tend to
minimize'the impact of peak exposure more pronouncedly
in a longer duration exposure than in shorter exposure.
Additional error may be introduced by extending the
measured short terra exposure to daily exposure.
© Other than the data from PHED, data in published
reports might have been developed with a methodology
not meeting quality assurance requirements of today's
standards.- For instance, analytical precision, spiked
sample recovery rates, and sampling design can vary
among investigators. Any statistical analysis on the
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occupational :e?mal exposure assessment - a review
September 30, 19"?6
combined data with varying quality is almost
meaningless.
Several factors and assumptions were considered when
applying the data from published pesticide studies and PHED data
to industrial operations. The impacts of these factors'and
assumptions include:
• Pesticide studies only report the exposure to the
active ingredient of the pesticide, which is usually
only a minor component of the mixture. For generic
applications, the desirable data is the amount of
mixture, not the active ingredient, that contacts the
skin. Therefore, it is assumed that the mixed solution
or the formulated product that contacts the skin has
the same concentration of active ingredient as in the
mixed solution or the formulated product itself. This
is a critical assumption in calculating the estimated
amount of mixture teaching the skin (gross dermal
deposition). However, different ingredients could vary
a great deal in physical properties, leading to
differences in deposition rate, evaporation, etc. In
some instances, the assumption may overestimate the
deposition.
• Data on concentrations of active ingredients in liquid
formulations are usually reported on a weight/volume
(lbs/gal) basis. A weight/weight ratio is needed if
the gross dermal deposition is to be calculated. Since
data.on the density of active ingredients is not
included in published reports or PHED, t-fiS density is
assumed to be the same as water. Up to ~'
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OCCL'PA TICNAl :£r«AL EXPCSURE ASSESSMENT - A REVIEW
Septemo«r 30, 1996
• Typical workplace conditions and work practices in ¦
pesticide operations are different than typical
industrial operations. For example, a pesticide mixing
operation tends to be of intermittent, short duration
operation. Industrial mixing may be continuous.
Pesticide mixing and loading may take place outdoors,
and the exposure reported may be affected by weather
conditions. Pesticide mixing involves more dilution
than a typical industrial mixing would. Another major
difference is in the amount of chemical handled. As
shown in Table 6-3, the amount of pesticide handled is
relatively small, except, for open mixing of granule, as
compared to a typical industrial operation. Industrial
mixing and loading often involve filling of 55-gallon
drums, tank cars, and tank trucks.
® The daily dermal retention shown in Table 6-4 is based
on the time or quantity normalized data extended to a
4-hr duration or to a quantity found in PHED tests.
The time normalized data provides a more conservative
estimate and is recommended for use with the CEB
method. If the quantity factor can be better
estimated, the quantity normalized data may turn out to
be more appropriate.
The current "Q" values for hand exposure in the CEB method
were developed primarily based on the data developed from a
series of experiments involving three kinds of oil applied to and
removed from the hands (Versar, 1984; EPA 1989b; EPA 1992c).
Though limited in scope and formulation type, this is the only
experimental data that were specifically designed to determine
generic dermal retention rate. The statistical design and test
protocol were such that the data also contain uncertainties
especially when applying it to industrial operations:
© Retention varies with individuals and techniques of
application on and removal from the hands. The
specific procedures tested may not be representative of
industrial scenarios.
• Data were reported on a per event basis; factors such
as duration or contact frequency were not documented
and are important factors that can affect dermal
retention.
• Data were developed only for three kinds of oils; they
may not apply to other kinds of liquids or solids.
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OCCUPATIONAL OERMAl EXPOSURE ASSESSMENT ¦ A REVIEW Septentwr 30, 1996
VII. BARRIER EFFECT OF PROTECTIVE CLOTHING
The wearing of protective clothing, work uniforms, or even
street clothes presents a barrier in the transmission of chemical
agent from the environment to the skin. Not all the chemical
deposited on the exterior of clothing will reach the skin. If
enough data existed, it might be possible to estimate a "Pass-
through" factor, defined as the percent of chemical reaching the
skin from outside the clothing, to assess the relative barrier
effect of protective clothing. The lower the factor, the better
the clothing in preventing the penetration and permeation of the
chemical. In this chapter, available'information and data on the
barrier effect of various types of clothing are evaluated to
determine whether there are sufficient data to allow modification
of the current estimating method.
The amount of chemical reaching the skin through clothing
and or protective equipment should be examined from two aspects:
the protection afforded by the clothing or protective equipment
per se and the nature of operation and work practices involved..
Many factors can affect the protection provided by clothing or
personal protective equipment, including, permeation, degradation,
and penetration. Consideration of the potential for permeation
and degradation of the protective clothing requires information
on the characteristics of the clothing, fabric construction and
finish, garment design and construction, and the characteristics
of the chemical (or formulation)- which is in contact with the
clothing:
• Fabric construction and finishes: Different fabric
characteristics such as fiber length, yarn size, and
fabric construction will affect chemical transmission
(Leonas et al., 1989). For example, fabric porosity
will determine how much direct penetration of chemical
agents can take.place. An open weave fabric will have
a higher penetration and permeation factors than a non-
woven fabric. Disposable clothing, with chemical
resistant coating will have a greater barrier effect
than uncoated clothing (Leonas and DeJonge, 1986) .
• Garment design: The shape, size, fit, and style of the
garment will determine how much skin area is covered
and how much chemical can enter the covered area
through openings. The need for comfort and manual
dexterity will dictate the types of clothing and
equipment used.
• Characteristics" of""the_"chemical-: - The-type -of—chemical
formulation will determine the mechanisms by which the
7-1
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OCCUPATIONAL GERWAl EXPOSURE ASSESSMENT • A REVIEW
September 30, 1996
chemical is actually transmitted through the 5 ;ic. A
dry powdery agent is likely to pass through t: fabric
by direct penetration, therefore the tightness the
weave will be the primary factor. A liquid formulation
can transmit through the fabric by permeation, i'.e.,
diffusion through wetting of fabric. A strong
absorbent such as cotton fabric will permit a faster
permeation or penetration than a less absorbing fabric
such as certain synthetic fiber. Even for the same
chemical,- different formulations can result in
different transmis'sion rates (Leonas", 1991; Staiff et
al., 1982) .
Penetration of the chemical through imperfections in the
protective clothing can be a significant contributor to dermal
exposure. The extent of penetration will be influenced by the
operation or work activity and work practices in using the
protective clothing:
• Operation or work activity: Body movement during the
course of work will affect the movement of chemical
agent through the fabric. For instance, movement of.
the forearms will create a "pumping action" between the
sleeve and the arm, promoting the migration of chemical
agent beyond the opening of the sleeve. Repeated
motion increases direct contact between the skin and
the clothing thus enhancing the transfer of permeated
chemical from the fabric to the skin.
• Work practices in using protective clothing: • How the
protective clothing is used also has an effect on
chemical pass through. If openings at sleeves, collar,
and pant legs are taped tight to the body, very little
entry through "pumping action" should occur. How often
protective clothing is changed also will affect how
much chemical will permeate through. Rips and tears
can occur during use, and any openings from rip.and
tears will become an entry point. Even if the
protective clothing is intact, heavier contaminant
loading expected near the end of a workshift may cause
a high rate of chemical penetration. All such factors
are in turn somewhat dictated by cost, comfort during
use, worker training and compliance, and other similar
factors.
Because of the factors as described above, dermal exposure
occurring while ^wearing ~wo"rk~or"protective -cloth-i-ng-is-best
determined under'actual field conditions for each type of
clothing for each chemical. While there is a considerable amount
of fabric and glove permeation data on different substances from
7-2
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OCCUPATIONAL OEXMAL EXPOSURE ASSESSMENT - A SEVIEU
Septentwr 30, 1996
laboratory studies, there are a limited number of field studies
on the barrier effect of clothing and gloves.
As described in Chapter II, the most commonly used approach
to evaluate dermal exposure is by the use of absorption pads. If
the pads are placed outside and inside the clothing, a comparison
of outside and inside deposition will indicate a pass- through ¦
factor. A different approach that uses pads made out of the test
fabric as the outer layer with absorption gauze underneath would
also allow evaluation of pass-through factor for the fabric. The
U.S. EPA's Office of Pesticide Programs suggested using data from
the outside patches in conjunction with standard "penetration
factors" generated from laboratory studies (EPA, 1987a) to
estimate exposure inside the clothing. These approaches
generally measure the amount of chemicals underneath the c
through penetration and permeation. Direct deposition through
openings on the clothing or through "pumping action" may not have
been included.
Another approach that had oeen used to account for the
effect of direct deposition used fluorescent tracers in
conjunction with video imaging technique (Fenske, 1988). This
method provides a visual display of deposition under the clothing
and allows an estimate of relative pass-through factors of test
"clothing covering all pathways of transmission. However, the
results provide only qualitative estimates of exposure.
Laboratory glove permeation testing is commonly used to
evaluate the permeation characteristics of a given
contaminant/glove matrix. Other factors such as elevated
temperature, stressing, and pressure applied to the glove during
use have been found to significantly reduce the protection
provided during actual use when compared with laboratory glove
permeation data (Gunderson et al., 1989; Zellers et'al*, 1993).
For those substances that are of high concern due to potential
dermal exposure, CEB currently only considers permeation and
degradation when, evaluating the effectiveness of gloves in
providing adequate protection (it is assumed that the glove
manufacturer's quality control'is acceptable to eliminate
imperfections in the glove material that may lead to
penetration).
The barrier effects of protective clothing has also been
examined by testing the absorption of chemicals through the skin
instead of just the chemicals penetrating through the clothing.
Keeble et al. (1993) used an in vitro skin model to examine the
capability of. fabric and skin alone and in combination in
reducing the dermal absorption of several organophosphorus
insecticides"The investigators found -that—the - knit- gloves ~o
100% cotton were effective in preventing the absorption of
7-3
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OCCUPATIONAL DERMAL EXPOSURE ASSESSMENT - A REVIEW
September 30, 19
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OCCUPATIONAL DERMAL EXPOSURE ASSESSMENT - A REVIEW Septerfjer 30, 1996
TABLE 7-1 PRELIMINARY DATA ON PASS-THROUGH FACTORS OF VARIOUS TYPES OF CLOTHING
] Chemical
J Formilation
Physical State
Operation
Pass Through Factor
Study Approach
Reference
Coveralls
Tyvek
Suit
Uorkpants I
Uorkshirt
Terbufos 15X
Granular
Loading and
spreading
10 - 20X
Comparison of
deposits on inside
and outside pads
Devine et. al.,
1986
Several
compounds IB-
reX
Uettabla powder
and aaulsified
concentrate
Mixing and
application
0 - 23X
Casparison of
deposits on inside
and outside pods.
Tyvek suits
include hood and
boots. Gloves
also used
EPA. 1988
FoaetylAl BOX
Uettable powder
in water
Mixing
15.9 X Shirt
3.5X Pants
Comparison of
deposits on inside
and outside pads
Fenske et. al.,
1987
Spraying
13.37* Shirt
2.IX Pants
Carberyl BOX
Uettable powder
Spraying
3.4X Chest
4.SX Back
6.9X Leg
Coeparison of
deposits on side
and outside pads
Leavi^t et.
al.'. 19B2
I Nitrofen 25X
Wettable powder
Nixing
4.12X
Deposit on pads
with test fabric
and absorbent
gauze at outside
of clothing*
Maddy et. al,
1980
H Nitrofen 75X
Ewtiificd
concentrate
Mixing
3.12X
Deposit on pads
with test fabric
and absorbent
gauie at outside
of clothing*
Maddy et. al,
1980
7-5
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OCCUPATIONAL DERMAL EXPOSURE ASSESSMENT - A REVIEW Septefflber 30, 1996
TABLE 7-1 PRELIMINARY DATA ON PASS-THROUGH FACTORS OF VARIOUS TYPES OF CLOTHING (Cont'd)
Chemical
Formulation
Phyaical Stat*
Operation
Pass Through Factor
Study Approach
Reference
Coveralls
Tyvek
Suit
Uorkpants &
Uorkshirt
Mitrofcn 25X
Uettable powder
Spraying
4.08X
Oeposit on pads
with test fabric
and absorbent
gauze at outside
of clothing*
Haddy et. al,
1980
Hitrofen 75X'
Eaulaifted
concentrate
Spraying
2.2«
Oeposit on pods
with test fabric
and ab6orbent
gauze at outside
of clothing*
Maddy et. at,
1980
Lindane 18.75X
Dry powder
Manual seed
treatment
(mixing)
25.3X Chest
2B.6X Back
30.6It For cam
25.OX Upper Arms
B.UX URier Legs
11.8X Lower Lega
Comparison of
deposits on inside
and outside pads
Fenske, et. al,
1990
Ethion 6X
Emulsion
Nixing
Spraying
4X
0.7X
Comparison of
deposits on inside
and outside pads
Davies et a I.,
1982
Dicofil
Eaulsified
concentrate
Mixing and
Spraying
3X
9X
Comparison of
deposits on inside
and outside pads
Nigg et al.,
1986
8 Molinate 10X
Granule
Mixing into
•praying solution
SIX
Comparison of
deposits on inside
and outside pads
Knarr et al.,
1985
Holinate 91X
Liquid
Mixing into
spraying solution
30X
Cooparison of
deposits on inside
and outside pads
Knarr et al.,
1985
* Pass-through factor calculated from reported dep, - itrat ion as: pass through factor « 100* inner layer deposit
exterior layer*inner layer deposits
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OCCUPATIONAL OESMAL EXPOSURE ASSESSMENT ¦ A REVIEW SepteiTtoer 30, 1996
VIII. CONCLUSIONS AND RECOMMENDATIONS
A. CONCLUSIONS
This document presents a review of available dermal exposure
data from pesticide mixing and loading and other similar
operations and evaluates the current method used by CEB in
estimating dermal exposure during industrial operations. The
important conclusions based on this evaluation are the following:
• The CEB method currently only assesses hand exposure.
The field monitoring studies routinely included
evaluation of exposure to other parts of the body, even
though hand exposure often constitutes the majority of
the total body exposure.
• The value of hand surface area used by CEB is not
current. Many other SPA publications cite other
values. The values as presented in Table 3-2 are .more
appropriate.
• The current input parameters for hand exposure using
the CEB method are found to be very similar to the
estimated gross dermal retention at the hands based on
the 90th percentile estimate from the PHED time
normalized data. The PHED estimated dermal retention
at other parts of the body could be used with the CEB
method.
• Available data in the literature indicate a maximum
dermal retention of 10 mg/cm2 for solids and 4 to 10
mg/cm2 for liquid. (Kissel et al., 1996a; Rutledge,
1988; Versar, 1984.) These maximum loading estimates
appear reasonable when- compated to a calculated
equivalent deposition of 0.95 mg/cm2 for solids and
0.98 mg/cm2 for liquid based on the study by Popendorf
et al. (1995)-. The maximum loading estimates are also
reasonable when compared to the 1,2 mg/cm2 deposition
for powder and 0.8 mg/cm2 for liquid mixing based on
the Indicative 90th percentile estimates of the
available data in published reports.
• Where comparable data are available, the 90th
percentile estimate from the PHED and the Indicative
90th Percentile deposition from published reports for
various body sections are generally within an order of
magnitude " oT~eacfi"othe r" However — there—i-s -no
consistent pattern as to which source of data will
8-1
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OCCUPATIONAL 3E5MAI EXPOSURE ASSESSMENT - A —VIEW
September 30, '996
generate a more nservative estimate for any body
section.
• In terras of evaluating the dose absorbed through the
skin, the deposition approach whereby only a fraction
of the deposit is considered absorbed, is acceptable
for solid or particulate media. The dermal absorption
approach whereby a skin permeation coefficient is used
to estimate absorbed dose directly, is theoretically
more appropriate for evaluating exposure to chemicals
in a liquid media. The methodology for estimating
dermal absorption for non-aqueous media for industrial
applications must be developed before this will be a
viable methodology. The absorption approach for liquid
chemical still needs additional research and further
evaluation.
• Significant correlation of dermal exposure with either
the total quantity of~AI handled or the total sampling
(exposure) duration was found only at a few body
sections based on PHED data. There is no clear
indication as to which factor is more appropriate for
predicting dermal exposure at any body section.
Similar arguments are found in published reports.
® The influence of physical properties such as particle
size, moisture content on solids deposition and
retention on the skin has been studied for soil
particulates, but has not been evaluated for industrial -
applications. There is limited data wi ./hich to
estimate the potential for dermal expos to solids in
industrial operations. However, a revi: af the
available data indicates that the curre;:. iefault
values used by the EPA for estimating deposition on the
skin appear to be reasonable. Two recent studies on
soil adherence rates on the skin found that physical
properties of the- soil such as grain size and moisture
content may affect the retention rate on the skin.
Similar factors may also have an effect on the
retention rate of solids in industrial operations on
the skin.
• The impact of clothing on providing a barrier to dermal
exposure needs further evaluation.
• There is very limited dermal exposure monitoring data
avaxlableTdr"i^ustrxal""activi-t-ies;--Thi3--LaGk--of-data
makes estimation of the potential for dermal exposure
during industrial operations very difficult. The
available-data with whi.ch. to assess dermal exposure is
8-2
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OCCUPATIONAL J=*MAI £XPCSUR£ ASSESSMENT - A REVIEW
SepteffiDer 30, '996
limited, but appears to result in reasonable estimates,
based on the analysis conducted for this report.
• Standardization of sampling methodologies ha3 largely-
been conducted in the pesticides areas, but sampling
techniques for the industrial environment have not been
standardized. Lack of standardization presents
difficulties in properly interpreting and comparing
data collected using different methodologies. Many
sampling and collection methodologies have not been
validated in industrial environmentsand quality
control procedures have not been standardized.
• Reporting of dermal exposure monitoring data is not
standardized. The lack of standardization in data
reporting makes interpretation of data, and comparison
between studies difficult.
• There is very limited information available on activity
patterns in industry. Unit area exposure at each body
section from the studies evaluated usually varies over
a range of several orders of magnitude. Based on a
review of the data available, variability in dermal
exposure may be influenced by a number of factors
including the task performed by the worker, worker
habits, and the physical properties of. the contaminant.
For example, unusually high exposure at the lower leg
was found in one study because most of the
mixing/loading operations studies consisted of pouring
liquid from 'one container to another below the waist
level, and liquid splashing may have cause relatively
high'exposure at lower part of the legs (Knaak, et al.
1989). Knarr et al. (1985) found unusually high
exposure at legs due to frequent contact with the spray
nozzle. Conversely, Chester et al. (1987) found that
most of exposure was concentrated in arms, trunk, and
hands. Lavy et al. (1980) reported high exposure at
the thighs, and observed that workers frequently rubbed
their hands against their pants at-the thigh area.
• Interpretation of results is critical. Retention of
chemicals on the skin surface is not necessarily linear
with exposure duration or quantity of chemical handled.
There is an upper limit to the amount of chemical which
can be retained on the skin. Due to extremely wide
variations of certain data sets, the mean value can
exceed the 90 percentile estimate.
• Hands generally have the highest estimated gross dermal
retention among all body sections during pesticide
8-3
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OCCUPATIONAL 3E3MAL
EXPOSURE ASSESSMENT
A REVIEW
Seocentier 30, 1996
mixing and loading operations. The next highest
retention is generally found at forearms, chest, thigh.
These are all body sections more likely to come into
direct contact with chemical during mixing and loading
operations. Within each formulation type/mixing method
matrix, one or two body sections may be found to have
an extraordinary high retention as compared to other
body regions. Further examination of the data often
reveals the presence of one or two unusually high
exposures among the data for that body section which
would have biased the data towards the upper end of the
distribution.
B. RECOMMENDATIONS FOR IMPROVING THE CEB METHOD
The CEB dermal exposure estimating method represents only a
preliminary estimate of the quantity of chemicals that may be
retained on the hands from a few, specific operations. Based cm
the field monitoring, data analyzed in this report, the following
approaches can be adopted to improve the application.of the
current CEB method:
• The.current "Q" values in the CEB method for hand
exposure tends to generate exposure estimates that fall
in the upper range of the distribution of the
applicable field data. Use-of the CEB method thus
provides a conservative estimate of exposure. Any
refinement in the estimates will need more field data
for validation. Based oil a review of the available
data and information collected and.evaluated, the
current methodology and input paramete. used by EPA in
estimating the potential for dermal ex- .. :ure during
industrial operations appear to be reasonable.
However, characterization of CEB estimates as bounding
estimates should be reevaluated for some operations.
The deposition of material on the skin may vary by
several orders of magnitude, depending on factors such
as the task performed by the worker, individual worker
habits, and other physical characteristics of the
contaminant. The data with which to estimate the
potential for dermal exposure in individual operations
is limited, and additional data and information is
needed to improve dermal exposure estimates.
• The estimate of dermal exposure on' outside clothing or .
on bare skin at various body sections can be 'calculated
using" "tfTe" PHED~'t~ime normalized data-.-—The—recommended,
values are shown in Table 8-1. These rates are
recommended for use with the CEB method to estimate
daily dermal potential dose rate. If the daily
8-4
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occupational :eswal exposure ASSESSMENT - A REVIEW
Seotemoer 30, 1996
exposure duration is much different than 4 hours or if
a better estimate of the quantity of chemical handled
is available, the time or quantity normalized gross
deposition rates presented in Chapter VII may be used.
• The EPA (1987a) values (shown in Table 3-2) for skin
surface area should be used.
• The deposition approach is appropriate to estimate
dermal absorption for solids but does not adequately
address the continuous process of deposition and
absorption for liquid media. The skin permeation
approach is more appropriate for estimating dermal
absorption for liquid media but further development is
needed before this will be a viable approach for
industrial scenarios. Appropriate initial and boundary
parameters may be developed from PHED data for use with
mathematical equations to estimate dermal absorption of
a liquid media in industrial operations.
TABLE 8-1
RECOMMENDED DERMAL RETENTION RATES AS
INPUT PARAMETERS FOR THE CEB DERMAL EXPOSURE ESTIMATING METHOD
Body Section
Demi Retention (M/ca1)
Mixing of Aqueous
Suspension
Nixing of Solution
Mixing of Uettable
Powder with Liquid
Dry Mixing of
Granule
Head/Face
15
15
10
20
Shoulder
10
10
110
50.
Upper Arm#
1 •
5
30
Chest
60
40
120
60
Back
10
10
100
10
Forearms
10
50
240
240
Thigh
110
30
90
160
Shin or Calf
• 30
30
..
Ankle
10
--
1
--
Source: Table 6-4, tias nsrsaWzsd data with rounding to the r»*r«st 1, 5, or 10 and with obviously irosuol
nutter' excluded. (1100 ag/ae2 at shin for mixing of aqueous suspension, 350 *g/cs^ at ankle for
nixing of solution; and 370 M/ca1 «t ankle for dry mixing of granule.) •
8-5
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OCCUPATIONAL DERMAL EXPOSURE ASSESSMENT • A REVIEW
September 30, 1996
C. RECOMMENDATIONS FOR FUTURE RESEARCH
The prediction of occupational dermal exposure is very
difficult because of the complex physical and physiological
processes involved and a lack of pertinent field data. The
available field data gathered in this document represent a
comprehensive review and analysis of readily available papers on
dermal exposure for mixing, loading, and associated operations
involving pesticides and a preliminary analysis of one of the
data files in PHED. The data should present a -fairly accurate
description of current knowledge and information on dermal
exposure from mixing and loading operations. However, much
research remains to be done. The following discussion provides a
few recommendations.
Further Analysis of PHED
By far, the PHED represents., the most structured source of
data, in fact, it is the only statistically valid data base
available. The PHED is a source of information which can be
extracted to further refine the estimating parameters needed in
predicting dermal deposition rate. Based on the data analyzed so
far, additional analysis on PHED data should include:
© Analysis of correlation between exposure and handling
rate (lb. Al/hr or gal. Al/hr). Current PHED structure
does not allow this analysis directly. The data will
need to be exported to a different data base file for
manipulation. If a better correlation is found with
this variable, a better estimate of exposure can be .
made.
• Comparison of exposure values measured outside of and
inside of protective clothing to evaluate .the barrier
effect of the clothing. Some of the records in PHED
contain both the inside and outside exposure values for
a body section on the same person. A comparison can be
made from such exposure values to evaluate the barrier
effect of various types of clothing. Inspection of raw
data input will be necessary to determine the type of
clothing used. Even if the outside and inside samples
are not from the same worker, it is possible to examine
all inside and outside data related to a specific type
of clothing'under similar work conditions to evaluate
the barrier effect of the clothing.
• With pass-through factors developed from applicable
PHED data to estimate the barrier effect of clothing,
it will be possible to estimate actual dermal exposure,
on bare skin underneath the clothing from the outside
8-6
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OCCUPATIONAL 3E5MAL EXPOSURE ASSESSMENT • A SEVIEV
September 30, 1996
clothing potential dermal retention data as recommended
in this document.
• Analysis of other data files in PHED. Dermal exposure
data relating to spraying operations are contained in
Applicators files and also in the
Mixer/Loader/Applicator files of the PHED. An analysis
on these additional files may yield results for
reference in developing a method to estimate dermal
exposure from industrial spray operations.
Field Studies
Ideally, field studies of actual dermal exposure monitoring
should be performed to validate a predictive model. At least,
laboratory simulation of industrial operations should be
conducted to evaluate the various parameters involved in any
modeling effort. The current CEB, EAB, and ORD particulate
estimating methods all are based_on a simple concept of extending
skin deposition on a unit area to- the entire section of the body.
Only a limited estimate of the deposition rate front hand
immersion tests and a few specific liquid handling operations has
been developed. The data developed in this document corroborate
the CEB estimates for hand exposure and add a few more parameters
for estimating deposition at other parts of the body. There is a
need for standardizing methodologies and interpretation of data.
Once the methodologies/interpretations are standardized, the
process of chemical deposition to be evaluated should include, in
addition to immersion:
• Settling of droplets, mist, or dust on skin
® Impingement of droplet, mist or dust particle on skin
• Chemical transfer through direct contact-
• Permeation or penetration through clothing, gloves, and
barrier cream .
« Retention of volatile compounds on the skin
• Retention of chemical on the skin and the total area of
skin contact from specific unit operations such as
electroplating, metal cleaning, spray painting,
pulverizing, spray drying, or liquid filtration.
Skin retention of chemicals through these processes needs to
be investigated and appropriate parameters developed.
Furthermore, there are many other factors that may greatly
influence the outcome of a dermal exposure assessment method.
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OCCUPATIONAL OERHAL EXPOSURE ASSESSMENT • A REVIEW
September 30, 19
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OCC'JPAnCNAL DE3MAL EXPOSURE ASSESSMENT - A REVIEW
September JO, 1994
only the net amount at the end of the sampling period.
Obviously, the volatility of the compound, the duration of
contact, the.original quantity deposited, and the ambient
temperature will all have an impact on how much is retained on
the skin at any time. A correction factor to adjust the estimate
downward needs to be considered.
5. Chemical "Loss" Through Dermal Absorption
For chemicals.with a property of rapid absorption through
the skin, the amount remaining on the skin will be in constant
flux reflecting the balance between the amount deposited and the ¦
amount absorbed (assuming little loss from evaporation). If a
dermal deposition rate for such chemicals is to be developed
through measurement with a pad or wipe sampling technique, the
amount measured may not represent the true exposure. Potential
"loss." through absorption should be considered to assess exposure
hazard through dermal absorption. The skin permeation
coefficient method of estimating: dermal absorption will be a
better approach to addressing such problems.
6. Skin-Hydration
Sweating may cause the migration of deposited chemicals from
one site to the other or cause the deposited chemicals to fall
off the body. It may also cause an increased absorption through
the skin. On,the other hand, it may increase the adhesion of
powdery chemicals. No quantitative estimate of these effects can
be made at this time. In general, skin hydration will tend to
cause an underestimate of the deposition factor.
7. Transfer Rate from Surface to Skin
Some industrial activities may be more appropriately
represented by a method which predicts the amount of contaminant
transferred from a surface to the skin. Such activities as
monitoring a process from an isolated control room, occasionally
entering a process area.to visually check equipment and process
monitors, taking samples using enclosed sampling apparatus, or
opening or closing-valves on a piece of equipment are common
activities where the primary exposure may result from contact
with contaminated surfaces. However, data on the transfer of
contaminants from surfaces such as these to the skin is currently
not available for industrial operations. This data is important
in improving, estimates of dermal exposure due to transfer of
contaminants from surface to skin in the industrial environment.
8-9
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CCC'jPAT !ONAl DERMAL EXPOSURE ASSESSMENT • A REVIEW
Septemcer 30, 19<36
8. Activity Patterns
There is very little information available with which to
characterize the activity patterns in the industrial environment.
Therefore, assumptions regarding the specific worker activities
or tasks performed, the duration of exposure, the quantity of
material handled, the potential surface area of contact (e.g., l-
hand, 2-hands, palm surface, etc.) are required to be made when
estimating the potential for dermal exposure. This information
is critical to improving our understanding of the environmental
and worker-related factors which contribute to dermal exposure.
Theoretical Studies
In this document, dermal deposition rates are developed for
estimating absorption with the fractional absorption approach fo:-
both the solid and liquid chemicals. Even though the fractional
approach is only appropriate for solids, the lack of adequate
skin permeation coefficients for- liquid media dictates that the
fractional, absorption approach be used for Liquids. -
At the present time, only the theoretical"equations for
estimating dermal absorption of chemicals in an aqueous solution
under "infinite" exposure conditions have been developed by ORD.
The permeation coefficients needed for these equations are
available for many chemicals either through experimental data or
through theoretical estimates.
However, data on permeation coefficients in non-aqueous
media, the type of data needed for occupational exposure
assessment, are not yet available. This is an obvious area for
future research. Furthermore, the ORD.equations developed for
dermal absorption of contaminants in polluted water will need to
be modified or used with different initial and boundary exposure
conditions to predict dermal absorption in occupational settings.
A wealth of data on surface retention rate for pesticide
exposures are available as shown in this.document. Studies
should investigate how such data can be used in conjunction with
the ORD equations to better estimate dermal absorption from
occupational exposure.
8-10
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OCC-JPATICML ;eshal EXPOSURE ASSESSMENT - A REVIEW
September 30, 1996
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occupational :eshal exposure ASSESSMENT • A REVIEW
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OCCUPATIONAL dermal exposure assessment • A REVIEW
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A REVIEW
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OCCUPATIONAL DERMAL EXPOSURE ASSESSMENT - A REVIEW
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OCCUPATION*!. DERMAL EXPOSURE ASSESSMENT • A REVIEW
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9-7
-------
OCCUPATIONAL DERHAL EXPOSURE ASSESSMENT • A REVIEW
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9-8
-------
OCCUPATIONAL DERMAL EXPOSURE ASSESSMENT • A REVIEW
September 30, 19
-------
OCCUPATIONAL DERMAL EXPOSURE ASSESSMENT - A REVIEW
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9-10
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OCCUPAT:CNAL 3E3HAL EXPOSURE ASSESSMENT - A REVIEW
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-------
OCCUPATIONAL 0E3HAL EXPOSURE ASSESSMENT
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9-12
-------
OCCUPATIONAL de?mal exposure assessment - A REVIEW
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9-13
-------
OCCUPATIONAL OERML EXPOSURE ASSESSMENT - A REVIEW
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9-14
-------
APPENDIX A
STATISTICAL DESCRIPTORS OF ESTIMATED GROSS DERMAL
DEPOSITION NORMALIZED BY QUANTITY OF CHEMICAL HANDLED
-------
io.-.-i.A-iw ..scss :ermal ;epos:ticn rates normalized 3y ^uantit^ ¦:?
HANDLED, ug/crn1/gal, ."SOU PKcD rOR EMULSIr IABL2I
CONCENTRATE l LIQUID CODE 1) WITH OPEN MIXING iMIXINC CCDE 1)
o:;ts::e :lcthing
Pr.dv ' zr.
V'/mtor -3 5 yaqsuremenr*
Arirh. X<*an
Standard Ce»viat:on
toaiflrri.-
Med: i.i
head
77
0. 0817
0.1551
0.0092
0.003J
neck front
23
0.0717
0 .0809
0.0367
0.0450
neck back
13
0.0959
0.2102
0.0L93
0.0300
.shoulder
81
0 .0359
0.0726
0.0075
0.0050
upper arms
15
0.0867
0.2235
0.0058
0.0033
cnest
80
0.0767
0.1593
0.0092
o.oaso
back
93
0.0267
0.0567
0.0050
0.0033
forearms
109
0.8299
4.0432
0.(2292
0.0342
thigh
64
7.8529
47 .9925
0.0125
0.0400
shin
14
0.5129
1.8907
A-087$
0.0050
cal £
22
0.4445
0 .8574
Q.04S0*
0.0384
ankle
43
1 .7005
7 .0623
0.«7S
0.0467
hands
21
141.0904
251.3890
3CJSH
64.6512
INSIDE PERSONAL CLOTHING
Rndv Sertian Niimh*r nf MMnurmamnta Ariel). Mean Standard DflViaCiOn gflgmfleric Mean UsdljUl
head
6
0.0008
0.0017
0 .0003
a.0008
neck front
0
neck back
0
shoulder
28
0.0025
0.0042
0.0017
Q.6QQ9
upper arms
15
2.S837
10.0022
0.0017
0.0008
chest
96
0.0409
0.1209
0.0058
Q.C03J
back
82
0.0225
0.0475
010033
0.0017
forearms
64
0.045?
0.0809
0.3058
0,00.5ft.
thigh
40
0.0567
0.0909
0.0133
shin
0
calf
22
0.0050
o
o
LTi
00
0.0008
0.0017-
ankle
32
0.324-4
1.7481
0.0025
o.ooir
hands
45 ¦
0.7481
1.5210
Q.M35
0.1896
Note: Values in shaded area represent the central tendency parameter that best characterizes
che distribution of Che data: arith. mean for normal distribution, geometric mean for log
normal distribution, and median Ear other distributions.
-------
TA3LE A-2
ESTIMATED 3P3SS DERMAL DEPOSITION PATES NORMALIZED BY 2CANTITY 3F CHEMICAL
HANDLED, ug/r.n:/gal, FROM ?HED FOR cMULSIFIABLE
CONCENTRATE (LIQUID CODE 1) WITH CLOSED MIXING (MIXING CODE 2)
u'ts::e :lathing
Icdv Sr>cz :~r. .V¦.¦.Trier
V=flqur«>ment.*n
VaW- 3 n
nead
20
0.0117
0.0192
0.CO33
0.003 3
r.eck front
0
neck back
0
shoulder
4
0 .0025
0 .0042
0.0008
0.0008
upper arms
13
0.0067
0.0125
0.CC33
0.0033
chesc
20
0.0275
0 .0475
0.0083
0.0058
back
20
0.0150
0 .0459
0 .0017
0.002S
forearms
14
0 .1735
0.5079
9>Qt<3
0.075L
thigh
14
0.3987
0.7097
9.0«7
0.0801
shin
S
0.0350
0.054 2
i,qio8
0 0042
calf
0
ankla
5
0.0142
0.0209
o.oass
0.0025
hands
0
INSIDE PERSONAL CLOTHING
Hnriv ><-cion Ahimbtir of r«mant-* irifk. Sfm*n StAndard Deviation C.anmatric Mm An Median
head
0
neck front
0
neck back
0
shoulder
0
upper arms
19
ff,0«»
0.0017
0.0009
0.0025
chest
14
0.0017
0.0017
ff:,090«
0.0025
back
14
0.0017
0.0017
wogt
0.0025
forearms
19
0.0017
0.0017
o.oooa
thigh
14
0.4262
1.5346
0.0025
o; o
-------
TABLE A-3
ESTIMAT ED :?.0S3 DEF.KAL DEPOSITION PATES NORMALIZED BY QUANTITY OF THEM IIAL
HANDLED, ug/cmV-jal, FROM ?HED FOR AQCIOUS
SUSPENSION !LIQUID
CODE -2) WITH
OPE.N MIXING (MIXING
CODE 1)
:-uts:3E clothing
Scdv Ssc.L-r. .Vu
nfcer 3f Measurements
Ariih. Mean
rH Hpyi^rinn
fjpomerrir vf«»fln
Vari' jr
haad
15
0. 1668
0 .5730
a.cuss
o ,oi:a
neck front
0
neck back
0
shoulder
16
0.0292
0 .0684
o.oioa
0 ,009 3
upper arms
6
0.0083
0.0050
a.0067
0.3067
chesc
16
0.5980
2 .1050
0.037S
0-. j 4 0 0
back
L6
0.0200
0.0294
0.0917
0.3067
forearms
6
0.0934-
0.1159
0,0417
3.0634
thigh
16
0.4971
0.6697
0.1785
0.2335
shin
10
5.1433
12.0780
Qv3»Si
0 .7599
calf
0
ankle
6
0.0809
0.1218
0,Q10»
0.0142
hands
16
10.6851
16.1038
3.1103:
3.4366
INSIDE' PERSONAL CLOTHING
Radv Sere i an ffimhar nf Mf>*xu n»irmng-« rtnTft, MfUM Standard navi*£inn Geammtric Mean Mgtii jf,
head
0
neck front
0
neck back
0
shoulder
0
upper arms
0
chase
6
0.0050
0.0067
0.Q633:
0.0025
back
6
0.0025
0.0025
~„
0 .0017
forearms
6
0.0075
0.0067
0,0050
0 .0050
thigh
0
s-hin
6
0.0033
0.0067:
O-'iCKW*
0.0067
calf
n
w
ankle
6
0.0042
0.0033
0.0033
0.0025
hands
6
1.0821
0.8406
0.768*
0.9777
Note: Values in shaded area represent the central tendency parameter that best characterizes
the distribution of tha data: arith. mean for normal distribution, geometric mean for log
normal distribution, and median for other distributions.
A-3
-------
TABLE AH
ESTIMATED DERMAL DEPCSITICJJ RATES NCP.MALIZED 9Y QUANTITY -ZF CHEMICAL
HANDLED, ug/cm1 .'gal, EROM PHED EOR SOLUTION
1 LIQUID CODE 4) WITH OPEN MIXING !MIXING CODE 1)
outs — i zlcthing
Sedy Si-zma number :£ Xpjsij r<=rrenr
-------
7A3LE A-5
estimated cscss :ermal deposition rates normaliced sy -jUANTirr of chemical
HANDLED-, ug/cm'/ib, FROM ?HED .-CR WE7TA3LE
PCWDER (SOLID CODE 1) WITH OPES MIXING (MIXING CCDE 1)
:ctsi:e :'_:thing
Irrv dumber of yaisuromenrg Arirh. Mean Standard Deviation r.eamec r re M°an
r.ead
25
0.0172
0.0284
5.0032
0.006 5
r.e:< :ronc
3
0.0009
0.0008
Q.0006
0.0008
neck back
S
¦0 .0004
0.0003
0.0002
0.0003
shoulder
19
0. 14 1S
0 .1353
0.-Q30€
0¦C'ii
upper arms
0
:hesc
31
0.0696
0.0307
0,0118
0 0157
back
31
0 .0356
0.0537
O.OOS7
0.0130
Sorearms
33
0.S060
1.4344
0.0345.
0.L5 51
thigh
31
0.2166
0.6961
0/0225
0.0627
shin
7
0.0512
0.0881
Q-0OS5;
0.0104
calf
6
0 .0032
0.0058
0.9014.
0 .0010
ankle
7
0.02ST
0.0445
0.0030
0.0125
hands
12
11.0889
25.9034
1.2306
INSIDE PERSONAL CLOTHING
Anriv i on
Vnmhor nF KM«urm«nt.»
Gnnrrmeri c Mn/in
Median
head
6
0.0009
0.0002
0.000*
0.0010
neck Eront
0
neck back
0
shoulder
17
0.1014
0.3398
c.oos*
0.0020
upper arms
0
chest
22
0.0637
0.2561
0.0015
0 .0010
back
22
0.0656
0.2604
(KQOIX-
0.0010
forearms
19
0.0412
0.0894
O.OOW
0.0071
thigh
21
0.0049
0.0065
&.0O1*
0.0010
shin
7
0.0021
0.0034
0.0005
0.0012
cal £
6
0.0009
0.0002
O.OOOf
0.0010
ankle
7
0.0048
0.0044
O.OOEOT
0.0083
hands
14
0.0279
0.0374
S-0O3*
0.0127 '
Note: Values
in
shaded
area represent
the central
tendency parameter
that best characterizes
cha distribution
of the
data: arith. mean for normal distribution, geometric mean for
log
normal distribution, and median for other distributions.
A-5
-------
TA3L2 A-5
estimated :scss dermal deposition RATES NORMALISED 3Y quantity cf chemical
HANDLED, uj/cm'/lb, FROM ?HED FOR FLCWABLE
POWDER '.SOLID CODE 2> WITH OPEN MIXING (MIXING CODE 1)
Ca.-- ¦
V'.i.TtfcT •?.*" y*>asur=rnf»ncs
A rich. Mean
Standard Dpviarinn
r.&nmpr r i r Moat
head
:i'
0.0119
0 .0193
0.003ft
neck front
0
neck back
3
0.0008
0.0006
0.0005
shculder
0
upper arm3
16
0.0393
0.0374
0.0235,
chest
16
0.0927
0.09S2
a:0388
back
16
0.03S4
0.0540
O.'OlOi
forearms
24
0.0939
0.1009
0.0374
thigh
16
0.6240.
1.0084
0.1.778
shin
16
0.0366
0.0425
0,0145
cal f
0
ankle
0
hands
0
Median
0 .003?
0.0007
0197
0,
o -
0
0
o.:. .3
0.0246
INSIDE PERSONAL CLOTHING
Radv Section Numhmr of Arir.h. Mmii Standard Omviar.inn Gmoamcric Mman . Median
head
0
neck front
0
neck back
0
shoulder
0
upper arms
16
0.0026
0.0032
0.0020
chest
24
0.0018
0.0016
a. mi
0.0015
back
24
0.0011
0.0009
0-0005
0.0015
forearms
16
0.0029
0.0022
».o
-------
ESTIMATED ZZCS3 DERMAL SEPCSITION' ?_ATES NOP-MALIIcD 8Y Quantity OF CHEMICAL
HANDLE:?, ug /Cir.' / L 3 » ?SCM PHED FOR GRANULE
'SOLID CODE -4 i WITH OPEN MIXING 'MIXING CODE 1)
v-.~y.zt
i:iv -¦? 7
Madsiiramsnrs
Arit.n. Mean Standard nevurtrin
Geometric V=sr
Med'»n
.-.sad
3
0 .0011
0.0015
5.0004
0 .00C3
r.aclc front
0
r.ecic bac'c
0
ahcuicer
LI
0.002S
0.0049
0.0006
0.000;
upper arms
3
0.0016
0.0021
,0.0503
0.:cod
chest
11
0.0036
0.0055
o.em
o
o
o
o
-J
back
u
0.0006
o .oooa
0.0002
0 . 0004
forearms
11
0.0095
0.0241
tr. 0033
0.0021
thigh
u
0.0273
0.OS 54
O.Ofi-45
0.0030
shin
0
cal f
0
ankle
3
0 .0336
0.0515
O.&C«
0.0065
hands
0
INSIDE PERSONAL CLOTHING
flarfv Ssgtion Numhor of Kms'jremanes Arich. MaanStandard Deviation gflfllMCrtg ttfMn iVfrfMrr
head
0
necJc front
0
neck back
0
shoulder
0
upper arms
3
0.0001
,0.0002
0.003*
0.0001
chest
s
0.0005
0.0002
QiBW*
0.0005
baclc
8
0.0004
0.0002
0.0QQ3
0.0004
forearms
3
0.0007
0.0010
0.0082
0.0002
t'high
0
shin
0
calf
0
ankle
3
0.0003
0.0005
0,0001
0.0001
hands
3
0.0033
0.0056
0.6062
0.0000
Mote: Values in shaded area represent the central tendency parameter that best characterises
the distribution of the data: arith. mean for normal distribution, geometric mean for log
normal'drstribut-ion-,- and median for other distributions.
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