DERMAL AND NON-DIETARY
INGESTION EXPOSURE WORKSHOP
NERL Human Exposure Research Program
September 17, 1998
by
Elaine Cohen Hubal
Kent Thomas
Jim Quackenboss
Ed Furtaw
Linda Sheldon
" CDA UnfcdSWa.
C i M 6i»>uniwal PwfcJm Aqwcy
Human Exposure Analysis Branch
Human Exposure & Atmospheric Sciences Division
National Exposure Research Laboratory
Research Triangle Park, North Carolina 27711
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ABSTRACT
A dermal and non-dietary ingestion exposure workshop was sponsored by U.S. EPA's National
Exposure Research Laboratory (NERL) on September 17, 1998. The purpose of this workshop
was to gatheT information on the state-of-the-art in measuring and assessing children's exposures
to pesticides via dermal contact with contaminated surfaces and objects as well as by non-dietary
ingestion. Although the NERL human exposure research program covers exposure from source
to dose, this workshop focused on characterizing concentrations of pesticides in the exposure
media (on surface/object) and on quantifying the transfer of contaminants to the skin surface or
mouth. The following report discusses the focus of the dermal exposure workshop, summarizes
the workshop discussions and identifies research priorities based on a review of the literature,
workshop discussions, and expert input.
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TABLE OF CONTENTS
I. Introduction 4
II. Goal and Objectives 4
III. NERL Dermal and Non-Dietary Ingestion Exposure Research Materials.... 5
IV. General Conclusions and Recommendations 11
V. Breakout Group Summaries 13
Group 1: Pesticide concentrations in exposure media and
scenarios for exposure 13
Group 2: Single event (microactivity) approach for assessing
dermal exposure 16
Group 3: Integrated activity (macroactivity) approach for assessing
dermal exposure 21
Group 4: Procedures for generating exposure data for children 24
List of Figures
Figure 1. Conceptual Model of Dermal Exposure 6
Figure 2. Mass Balance on Contaminated Surface 7
Figure 3. Mass Balance on Skin Surface 8
List of Appendices
Appendix A: Agenda A-l
Appendix B: List of Participants B-l
Appendix C: Dermal and Non-Dietary ingestion Exposure Research Questions C-l
Appendix D: Revised Bibliography D-l
Appendix E: Literature Summary E-l
Appendix F: Chlorpyrifos Exposure Assessment F-l
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I. Introduction
A dermal and non-dietary ingestion exposure workshop was sponsored by U.S. EPA's National
Exposure Research Laboratory (NERL) on September 17, 1998. The purpose of this workshop
was to gather information on the state-of-the- art in measuring and assessing children's exposures
to pesticides via dermal contact with contaminated surfaces and objects as well as by non-dietary
ingestion. The workshop agenda and a list of participants are provided in Appendices A and B,
respectively. The following report discusses the focus of the dermal exposure workshop,
summarizes the discussions held during the workshop, and identifies research priorities based on
review of the literature, workshop discussions, and expert input.
II. Goal and objective
NERL is currently evaluating and expanding its dermal and non-dietary ingestion exposure
research program. In addition, NERL is charged under the Food Quality Protection Act (FQPA)
to study children's total exposure to pesticides. Because direct dermal exposure and non-dietary
ingestion are potentially important pathways that are currently difficult to quantify, NERL will
be focusing a significant effort on understanding the important factors influencing these
exposures. We then plan to develop the data and models required to quantity' exposure (contact
with a contaminated medium or potential dose) by these routes. We also hope to structure our
dermal exposure research program to address the uncertainties and data gaps that can be used to
meet NERL's long-term objectives of developing methods for exposure assessments, conducting
exposure studies, and reducing the uncertainties associated with exposure estimates.
The September dermal and non-dietary ingestion exposure workshop was part of this research
effort. The goal of this workshop was to gather information on the state-of-the-art in
measuring and assessing children's exposures to pesticides via dermal contact with
contaminated surfaces and objects as well as by non-dietary ingestion. Although the NERL
human exposure research program covers exposure from source to dose, this workshop focused
on characterizing concentrations of pesticides in the exposure media (on surface/object) and on
quantifying the transfer of contaminants to the skin surface or mouth.
The five specific objectives of the workshop were to:
1. determine the best approach (quantifying micro versus macro activity exposures) for
assessing dermal and non-dietary ingestion exposure,
2. identify methods available to measure dermal and non-dietary ingestion exposure,
characterize strengths and weaknesses of each method, and understand how these
methods can be used to assess exposure,
3. identify data available to characterize and quantify dermal and non-dietary ingestion
exposure,
4. determine what additional data, measurement methods, and models are required to assess
dermal and non-dietary ingestion exposure, and
5. identify significant dermal and non-dietary research needs.
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III. NERL dermal and non-dietary ingestion exposure research materials
The following materials were prepared for use during the workshop.
A. Conceptual model of the dermal and non-dietary ingestion exposure process
A conceptual model of the dermal and non-dietary ingestion exposure process (Figure 1),
including detailed descriptions of the model components for the contaminated surface (Figure 2)
and the skin surface (Figure 3), was developed. This model will be used by NERL researchers to
identify and prioritize dermal exposure research needs.
The overall model depicted in Figure 1 shows the dermal exposure process from source to
absorbed dose. Only dermal contact and non-dietary ingestion are depicted in this figure.
Pesticides may be released into the outdoor or indoor environment by residential, commercial, or
agricultural use. Once released into the environment, pesticides can transfer from one medium to
another (e.g., air to soil) and from one microenvironment to another (e.g., yard to house).
Contact with an exposure medium results in an exposure. For these routes, exposure is a
function of the mass transfer of pesticide from the exposure medium to the skin or mouth per
contact. Contacts resulting in exposure are a function of human activity patterns (indicated bv
the shaded ovals). Finally, uptake of the pesticide through the skin or the gastrointestinal tract
will result in an absorbed dose. The transfer from source to exposure media and from exposure
media to the body are only superficially presented in the conceptual model. Each box on the
model could be expanded to show in detail the fate and transport of pesticides in the given
compartment.
For the purposes of this workshop, two of the model components were developed further. The
mass balance for pesticide on the contaminated surface is depicted in Figure 2. Pesticide
residues are initially deposited from the air onto the surface. Residues bound to soil and dust can
be transferred from the air onto the surface or directly deposited from shoes during track-in
events. Important losses from the surface include those due to vaporization and cleaning. Both
residues and contaminated particles can be transferred to and from the skin surface during
contact activities or irreversibly to the body during mouthing of the contaminated surface.
The mass balance for pesticide on the skin surface is presented in Figure 3. Pesticide can be
transferred during contact with any contaminated exposure media. For residential pesticide
exposure, transfer from contaminated surfaces such as floors and furniture is potentially
significant. Once on the skin, pesticide residues and contaminated particles can be transferred
back to the contaminated surface during subsequent contact, loss by dislodgement or washing, or
transferred into the body by percutaneous absorption or hand-to-mouth activity.
B. Dermal Exposure Assessment Approaches
Application of this conceptual model will depend on the assessment approach selected. Different
^assessment-approaches-provide-different-ways-of integrating exposure over ,time.and.space. It is
important to understand that the temporal and spatial scale of activity patterns, surface
concentrations, and transfer efficiencies that must be measured, will depend on the assessment
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approach that is used. Two main approaches are currently used and these are discussed in
general terms below.
J. Microactivity approach
In the microactivity approach, dermal and non-dietary ingestion exposure is explicitly modeled
as a series of discrete transfers resulting from each contact with a contaminated surface. In this
approach, the dermal or non-dietary ingestion exposure associated with a given microactivity or
event (e.g., each time a child touches a given object) is quantified, as is the number of times
during a day that each microactivity is performed.
Eder (mg/day) = C$urf (mg'cm2) x TF (unitless) * SA (cm2/event) * EV (events/day) (1)
Where Eder = dermal exposure associated with a given event (mg/day)
Csurf = total extractable contaminant loading on surface (rag/cm2)
TF = fraction available for transfer from surface to skin (unitless)
SA = area of surface that is contacted (cm2/event)
EV = event frequency (events/day)
The transfer factor, TF, can be further defined as:
TF (unitless) = TR (mg/cnr) / Csurf (mg/cm2) (2)
Where TR = transferable surface residue, the mass of contaminant transferred to
the skin or a skin surrogate per unit area of contacted surface (mg/cnr)
The simple equation presented here does not account for variations in transfer efficiency or
surface concentration with time and number of contacts. In addition, summation over all events
during a given time period is required to predict dermal exposure for a given activity. Data
required to use the microactivity assessment approach include measures of total extractable
pesticide, transferable pesticide associated with a particular surface, and microactivity
information.
2. Macroactivity approach
In the macroactivity approach, dermal and non-dietary ingestion exposure is modeled using
empirically-derived transfer coefficients to lump the mass transfer associated with a series of
contacts. The macroactivity approach has been used extensively to assess occupational exposure
of agricultural workers, and has also been applied in a residential setting for adults performing
choreographed reproducible activities. In this approach, the dermal and non-dietary ingestion
exposure associated with a given macroactivity (e.g., playing in the yard) is measured and used
to develop an activity-specific transfer coefficient.
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Edrr (rag/'day) = ED (hr/day) * TCdsr(cm2/'hr) * Csurf (mg/cm2)
(3)
Where Eder = dermal exposure resulting from the completion of the activity on
which the associated transfer coefficient is based (mg/day)
ED = exposure duration that represents the time spent involved in a
specific activity as defined by the transfer coefficient (hr/day)
TCder = dermal transfer coefficient (cm2/hr)
Csurf = total extractable contaminant loading on surface (mg/cm2)
The transfer coefficient. TCder, provides a measure of dermal exposure resulting from contact
with a contaminated surface while engaged in a specific activity. In equation 3, the transfer
coefficient has been defined as follows.
TCJer (cnr/hr) = Ede, (mg'day) /[ED (hr/day) * Csurf (mg/cm2)] (4)
By combining equations (1) and (3) and rearranging, the transfer coefficient can be related to the
transfer factor in equation (1).
TCder (cnr/hr) = TF (unitless) x SA (cnr/'event) * [EV (events/day) /ED (hr/day)] (5)
Equation (5) explicitly demonstrates that the transfer coefficient can be used to lump the
uncertainty associated with the transfer efficiency, contact surface area, and contact events into
one unknown factor. Dermal loading, exposure duration and aggregate surface loading data are
required to develop the activity specific transfer coefficients. Once transfer coefficients are
developed, exposure can be estimated by measuring surface loading and activity duration. The
dermal transfer coefficient can also be defined in terms of the transferable surface residue. In
that case, equation 3, as well as the input data, would need to be modified accordingly.
C. Dermal Exposure Research Questions (Appendix C)
A scries of questions was developed using the conceptual model. The questions provide a
framework for systematically reviewing the literature and evaluating the important factors for
measuring and assessing children's exposures to pesticides via dermal contact with contaminated
surfaces and objects as well as by non-dietary ingestion. The resulting information can be used
as input to both assessment approaches.
D. Bibliography and Literature Summary Sheets
A thorough review of the dermal and non-dietary ingestion exposure literature was performed.
Because several relevant reviews were identified for literature published prior to 1990, the
emphasis of this review was on literature published from 1990 to date. Workshop participants
reviewed this bibliography and provided the citations for any relevant literature and/or data that
had not.beenincluded. JThe revised bibliography,is presented in two parts (Appendix D). The
first covers the peer-reviewed literature and the second covers U.S. Government reports and
other Agency research products. In addition, many of the most significant references were read
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and summarized according to the dermal exposure research questions. This summary is
presented in Appendix E.
E. Working definitions of dislodgeable and transfer efficiency
In the course of conducting the literature survey and the workshop, it became apparent that there
was some discrepancy in the way that individual researchers define the term dislodgeable.
Researchers in the human exposure field currently use the term in two very different ways.
In the first, dislodgeable residue or dust is defined as the amount of residue or dust on a surface
(e.g., carpet) that can be dislodged using extraction methods including HVS3 (e.g., U.S. EPA
1998a). Others define dislodgeability as the percent of the pesticide deposited on, or extracted
from, a surface that is actually transferred to the skin (e.g., Camann, D., et al.,1996).
Therefore, for clarity in this report, we will avoid explicitly using the term dislodgeable. We will
define the term extractable surface loading as the total amount of residue or dust on a surface
that can be dislodged using extraction methods. Extractable surface loading is the quantity C5uJ(
used in equations 1 and 3. Methods that are used to measure extractable loading include
deposition coupons, HVS3, and some surface wipe techniques.
We will define transferable surface residue as the amount of residue or dust-bound residue on
a surface that can be transferred from the surface to the skin or a skin surrogate (TR in equation
2). Methods such as hand press and PUF roller are used to measure transferable surface residues.
Transfer fraction or transfer efficiency is then the ratio of transferable surface residue to
extractable surface loading.
IV. General conclusions and recommendations
The workshop was organized into four breakout groups to cover the following topics: Pesticide
concentrations in exposure media and scenarios for exposure, Microactivity approach for
assessing dermal exposure, Macroactivity approach for assessing dermal exposure, and
Procedures for generating exposure data for children
Each group was given specific questions to discuss and members were charged with identifying
data gaps and recommending research needs for the group topic. Each group considered the
specific objectives of the workshop. The EPA facilitators guided the group discussions to insure
that time was allotted to each of the questions and to keep discussions focused on addressing the
group charge. Toward the later part of the session, the group discussion was summarized by the
facilitator and the rapporteur. The rapporteurs then presented highlights of the group discussions
to all workshop participants. Breakout group summaries were prepared by the EPA facilitators
based on group discussions and the rapporteurs' presentations. These summaries are presented
below.
A final source of information was obtained from the group of external experts in the field of
dermal and non-dietary ingestion exposure who were charged with reviewing the materials
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prepared by EPA. Reviewers were also asked to identify the three most important research
questions that must be addressed to better understand, quantify, and assess children's exposures
to pesticides via dermal contact with contaminated surfaces. Finally, these experts reviewed the
NERJL bibliography and identified any relevant published materials that were not included.
One of the major issues that was discussed at length during the workshop involved the two
assessment approaches (quantifying micro versus macro activity exposures). Workshop
participants could not come to a consensus on which of the two approaches should be the focus
of future research and exposure assessment activities. Rather it was recommended that both
approaches for assessing dermal and non-dietary ingestion exposure be explored.
Research directed toward the microactivity approach will increase our fundamental
understanding of the mechanistic factors influencing dermal and non-dietary ingestion exposures.
Unfortunately, the data requirements associated with the microactivity approach are extensive
and the time and resources required to obtain sufficient data to perform reasonable exposure
assessments may be significant.
The macroactivity approach affords the possibility of developing screening level exposure
assessments in a shorter time frame and with fewer resources than would be required for the
microactivity approach. However, the macroactivity approach was developed to assess
occupational exposure in an agricultural setting where workers are engaged in similar activities
and are exposed to relatively homogeneous environmental concentrations of pesticides. The
feasibility of applying the macroactivity approach for the varied activities of infants and children
in the heterogeneous residential or other indoor and outdoor environments needs to be studied.
The macroactivity approach will only be useful if exposure can be adequately quantified by
lumping children's activities into a relatively small number of macroactivities.
Based on all sources of information (the NERL literature review, the workshop breakout group
discussions and summaries, and the expert review and input) the following significant dermal
and non-dietary data collection and research needs were identified. Only general
recommendations are summarized here. More specific research needs will be identified and
prioritized in a research strategy that will be published in the peer reviewed literature.
A. Environmental Concentrations
Although significant work has been done on developing methods and on measuring pesticide
concentrations in exposure media, more information is needed on the form of the pesticide
contamination (residue or bound to house dust), the transferability of the pesticide, the
distribution on surfaces throughout a residence, and the variations of these with time. A very
significant data gap exists related to the patterns of pesticide use in the microenvironments where
•xhildren^spend^the-majority-of-their-time. ' Detailed
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B. Microactivity Exposure Assessment Approach
Very little data on age-specific microactivity patterns have been collected. The need for
additional data in this area is significant. Information on the important microenvironments in
which children spend time is needed. Once these have been identified, the significant
microactivities occurring in the microenvironments need to be determined. Studies are also
needed to identify and understand the significant mechanisms and parameters that determine the
net transfer of pesticides from a surface to skin and from a surface or skin to the mouth.
C. Macroactivity Approach
The feasibility of using the macroactivity approach to assess children's exposures in a residential
setting should be tested with existing data or a small-scale study before additional research
priorities in this area are identified. As mentioned above, the macroactivity approach will only
be useful if exposure can be adequately quantified by lumping children's activities into a
relatively small number of macroactivities. The important macroactivities need to be identified.
D. Studies in Infants and Children
Both the microactivity and macroactivity exposure assessment approaches need to be confirmed.
It is universally recognized that to do so, exposure estimates must be compared with biological
measurements. Methods for biomonitoring in infants and young children need to be developed
and improved.
V. Breakout group summaries
A. Breakout Group 1: Pesticide Concentrations in Exposure Media and Scenarios for
Exposure
1. Charge
a. Identify and prioritize important scenarios
Several exposure scenario categories that need further study were identified. However, the
Group did not attempt to numerically prioritize such scenarios. These include low-income
housing scenarios, because some available data have suggested that low incomes are associated
with higher exposures; daycare centers and other locations where very young children spend time
have not been as well studied as have residences or school locations where older children spend
their time. These exposure scenarios warrant further research, especially since FQPA identifies
infants and children as targets for protection.
b. Determine what additional data and measurement methods are required to characterize
exposure media concentrations and associated potential exposures for the most important
scenarios
-The Group recognized that-many-sampling-and-analysis methods exist^for-determining-pesticide
residue concentrations in a wide variety of media. The available methods are adequate for
selected situations, but not for all conditions and pesticides of interest. In general, methods for
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residue transfer efficiency are not as robust as those for media concentrations. Perhaps the
greatest need in the area of transfer efficiency methods is to better understand the
representativeness of the various methods for actual human exposure. Additional data are
needed to allow better evaluation of all exposure pathways. Current data axe inadequate except
for initial approximations; hence, prioritization of scenarios cannot now be done rigorously.
2. Answers to workgroup questions
a. Availability of acceptable methods for measuring media concentrations of pesticide
residues and their dislodgeability, transfer efficiency, and dermal loading
For media concentrations, acceptable analytical methods are available for selected
but not all situations of concern, and for most, but not all, pesticides.
Transfer efficiency methods are also available, but are less robust than
concentration methods; transfer efficiency test results are highly variable.
Bioavailability of residues on skin is indeterminate (however, the charge to the
Workshop and Group did not encompass this issue).
b. Additional work needed with current methods so that resulting data can be used for
exposure assessment
- More study is needed on concentrations in media, changes in dermal loading over
time, and residue migration and redistribution among phases and media including
dust particles of various sizes.
- Studies are also needed to assess the transfer efficiency and relative
bioavailability of residues as a function of age of the residues.
- Sensitivity of methods must be consistent across media. Methods for certain
media may need improvement more than those for other media.
Transfer efficiency methods are surrogates for residue transfer to human skin; the
relationships among the various methods, and their representativeness for actual
human exposure, are questionable and need more study.
- More studies are needed to be able to apportion the sources and exposure
pathways.
- A better understanding of how to interpret dermal loading data is needed.
A tape stripping method has been reported for evaluating contamination within
different layers of skin. This method should be evaluated.
- A better understanding of the relationships between contact variables (pressure,
duration, repeated contact, existing dermal loading, wetness, static press vs.
smudge, etc.) and transfer of residues from surfaces to skin is needed.
There is uncertainty about the efficiency of transfer of residues from skin (and
other objects) to mouth in mouthing activities
- A broader range of pesticide ingredients and formulations should be studied.
- Correlation between air concentrations and dermal wipe residues was seen in
"someNHE-XAS-data;this-relationshipshouldbebetter understood.
There is a need for an "NHANES for kids" study.
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Adequacy of existing data to determine highest potential acute and chronic exposures
- For acute exposure - data are currently inadequate except for preliminary
estimates.
- We need to better evaluate all exposure pathways.
- For chronic exposure - relative importance of pathways is unknown.
- There is a lack of knowledge about the distributions of residue concentrations to
which the general population is exposed and the changes in these distributions
over time.
- Information on pesticide usage to determine acute exposures to children
- Currently available information on pesticide usage is inadequate, especially for
non-residential settings such as daycare centers. There are ongoing studies trying
to address this question.
Some states and institutional users may have information which could be obtained
about pesticide usage.
Usage patterns change over time.
- Formulation vehicles and application methods are changing over time. These
factors affect distribution, dislodgeability, and transfer efficiency.
Prioritize exposure scenarios
We need to better understand exposure scenarios for children living in
low-income housing. These settings may be related to higher exposures.
- Daycare centers and other exposure scenarios for very young children need more
study.
- The importance of many specific microactivities is not well understood.
Additional Literature and Data Identified During Discussions
Bob Krieger of UC-Riverside has data from a study of a family exposed after a fogger
was used; chlorpyrifos metabolite was detected in urine for >30 days. However, these
data are not reported in the peer reviewed literature. It is uncertain what the plans are to
report these data.
A tape stripping method for determining residues at different layers or depths within the
skin has been reported in the literature (Tsai et al.. 1991; Chambin-Remoussenard et al.,
1993).
S.C. Johnson Co. conducts usage surveys; perhaps some of their data could be obtained.
The Chemical Specialty Manufacturers Association (Jeff Driver ofrisksciences.com) has
a task force study underway; this may be a source of useful information.
John Adgate at the University of Minnesota supervises a Master's student working on a
thesis on household pesticide inventory data. Jim Quackenboss will obtain a copy of this
data when it becomes available.
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B. Breakout Group 2: Microactivity Approach for Assessing Dermal Exposure and
Non-Dietary Ingestion
1. Charge
a. Evaluate the feasibility of a single event (microactivity) approach for assessing exposure
The feasibility of the microactivity approach for assessing dermal and non-dietary ingestion
exposures is not yet known. Under this approach, knowledge about the frequency, duration, and
location of a person's activities and contact with contaminated surfaces is combined with
information on the transfer efficiency of a pollutant to assess exposure. Since dermal and
non-dietary ingestion exposure to many pollutants occurs as a series of discrete transfers
resulting from each contact with a contaminated surface, the microactivity approach would
appear to offeT the most realistic exposure assessment. However, implementing this approach
requires a great deal of information about how children's activities affect their contact with
surfaces over different time intervals and about the parameters associated with physical transfer
of the pollutant from surface to skin, from skin to mouth, and from surface to mouth. Use of a
microactivity approach will require much additional information about human activities and
pollutant transfer coefficients. Collection of these data will be particularly important for young
children since they are likely to have a much greater degree of dermal and non-dietary ingestion
exposures resulting from their increased contact with potentially contaminated surfaces.
b. Identify and prioritize important exposure events
On a larger scale, acute dermal and non-dietary ingestion exposure to pesticides will be highest
in locations where pesticides have been recently applied. Of particular importance are periods
shortly after pesticide application in the places children spend most of their time: indoor
residential, outdoor lawn, and daycare or school settings. These scenarios should receive the
highest research priority. Due to the persistence of many pesticides in indoor environments,
chronic dermal and non-dietary ingestion cannot be ruled out as an important exposure pathway
for long-term exposures. Again, the children that spend a great deal of time at locations with a
history of pesticide application are likely to be more highly exposed. To understand the relative
importance of different exposure pathways for chronic exposure, inhalation and dietary intake
data will be need to be collected or evaluated along with dermal and non-dietary ingestion
exposure data .
On a micro-scale, there is not much information available to determine the most important
individual exposure events. For example, il is not clear whether the cumulative dermal exposure
that would Tesult from playing on, or crawling over, a contaminated carpet leads to higher
exposures than non-dietary ingestion of dust from the carpet. An order-of-magnitude assessment
performed for chlorpyrifos using assumptions found in the Office of Pesticide Programs Standard
Operating Procedures for Residential Exposure Assessments (Appendix F) provides a first
approximation for prioritizing exposure pathways, and highlights the need for more information
to prioritize" the most important "dermal and non-dietary ingestion exposure pathways for
micro-scale events.
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c. Additional measurement methods and data requirements
In many cases, existing methods are available and are being applied to gather data that could be
used in the microactivity approach. Of particular interest are planned or ongoing studies
involving videotaping and activity classifications for children. The monitored activities include
children in indoor and outdoor residential settings and activities that could lead to contamination
of food as it is consumed by children in home and daycare settings. Activity data derived from
these planned studies, and additional data from new well-planned activity monitoring, will need
to be organized and made available to researchers with an interest in the microactivity approach
In order to better understand the physical processes of contaminant transfers on a microscale
level, additional data must be gathered through research. In particular, transfer factors must be
measured for a variety of conditions, with a particular emphasis on conditions that are applicable
to young children. Transfer efficiency data that are needed include factors from several different
kinds of surfaces, for a range of contact pressures, moisture, and durations, and for a range of
contaminants adsorbed to surfaces or on particles. Measurement methods that provide
information about transfer efficiency of residues have been developed. More testing is needed to
assess comparability of these methods and how well they represent actual transfer to skin and
mouth.
2. Answers to workgroup questions
a. Advantages of the microactivity approach
- If the microscale activity and transfer parameters are well understood, the
microactivity approach should provide dermal and non-dietary ingestion exposure
estimates that are much closer to reality than estimates derived from more general
approaches.
Performing research to characterize the activity and transfer parameters will lead
to an increased understanding of dermal and non-dietary ingestion exposure
pathways, the factors influencing these exposures.
- Both mechanistic (event-by-event) and stochastic (activity and contact
distribution) approaches and models can be supported using this approach.
The microactivity approach requires an understanding of the mechanism that may
lead to better characterization of dermal and non-dietary ingestion exposures for
younger children.
b. Disadvantages of the microactivity approach
- This approach requires many more data points to characterize or measure
exposures.
Laboratory generation of activity and transfer data will be labor and data
intensive, and field studies may also be more labor intensive in order to collect
and process detailed activity information.
- The large number of parameters that are needed for modeled or measured
,exposures-mayrCause.increased vanabilityin-exposure-estimates.dueto
propagation of errors or improper classification of an important variable.
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Understanding single transfer events is very complex due to the wide variety of
factors at work (surface area, pressure, moisture, surface type, residue type, etc.)
and the short time scales for changes in these factors.
Events likely to result in significant exposures
Crawling is believed to be one of the most important exposure events due to long
exposure times and the large surface area in contact with potentially contaminated
surfaces.
Non-dietary ingestion resulting from hand-to-mouth activities is potentially very
important due to the relatively large mass-transfer potential.
- Object-to-mouth contact events may be very important due to the direct nature of
ingestion and the possible increase in transfer efficiency resulting from saliva
contact.
Contact with less absorbent surfaces will likely make residues or contaminated
dusts more accessible for transfer during contact events.
- Contaminated clothing may be important because the coniact period may be
greatly extended.
- Indirect dietary ingestion exposure (contamination of foods during consumption)
may be important because of the direct nature of ingestion and the potential for
moisture and saliva increasing the mass transfer of residues.
Priority for method or data needs for the events
- Research and data needs could not be prioritized based on existing data. In
general, it is believed that these are all important events for cumulative exposures
in children and that data are needed to characterize each event.
Temporal and spatial scales
- Dermal and non-dietary ingestion will occur due to activities that result in contact
with contaminated surfaces over time scales of seconds to minutes.
On a microscale, the sequence of events is probably important. For example,
mass transfer to a hand after the child has put fingers in the mouth may be higher
than for a dry hand for some residues. Residues transferred to the skin during one
contact may be partially removed from a later contact. Also, residue transfer rates
may decrease as repeated contacts are made with a contaminated surface.
Contact and residue transfer will be an ongoing process. It may be necessary to
classify spatial scales in terms of specific locations (indoor home, lawn, daycare,
school) based on the contaminants available for transfer and the specific kinds of
activities performed by the child in those locations. It may be possible, from
observational data, to classify contact scenarios or parameters for specific
locations and to develop activity distributions for children in specific locations,
"his"kind of classification may'be bu'ilt into a macroactivity approach.
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Data that must be generated to characterize exposure events
Activity
• Time factors associated with specific activities (amount of time children
spend playing outdoors, watching TV, etc.).
• Microscale activity frequency and contact parameter data (surface area,
pressure, static vs. smeared, wet vs. dry) are needed by location and age.
¦ Video data (current collection in several studies) needs to be increased and
consolidated.
• Data needed should be a combination of National Human Activity Pattern
Survey (NHAPS) data for general location distributions and video data for
distributions of microscale activities within those locations.
Transfer
• Experiments are needed for existing methods to provide comparisons
(hand wipe, nnse, PUF roller, etc.) and relation to actual exposure [highest
priority].
• Contact duration effects on transfer need to be characterized [second
highest priority based on lack of existing data].
• Wet vs. dry skin and saliva effects on transfer factors need to be
measured.
• Differences and magnitudes of transfer coefficients resulting from
different contact factors (surface characteristics, contact surface, contact
pressure, static vs. smeared contact, contact orientation) need additional
data generation.
• Negative transfers from skin (losses from the skin back to surfaces during
contacts) need to be examined.
Methods needed to characterize events
- Videotaping on the appropriate scale to capture important contact events and
parameters. Both laboratory and real-world data are needed.
Biomechanical measurements are needed to better determine the appropriate
measurement methods and testing procedures for contaminant transfers.
- Methods that are applied to children at several age ranges are necessary.
- Due to the difficulties in using children in testing methods involving toxic
materials, a robotic approach might be considered.
In general, well characterized methods for measuring surface (or dislodgeable
residue) concentrations and residue transfers are needed to provide data for the
microactivity approach .
Do acceptable models exist?
The Stanford/Zartarian DERM model is based on the microactivity approach and
-includes-temporal-and-spatial parameters. -It-can be-used for simulations to
evaluate or rank the important parameters and may serve as a starting point for
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improved models based on new activity and transfer parameter data that become
available.
- Models from EPA (the Residential Exposure Assessment Guideline Method 2.3.2
for example) and other researchers are available for estimating dermal exposures.
In general, these models or guidelines do not allow input for all of the time and
spatial scales and the multiple contact parameters needed to fully implement the
microactivity approach for children. With additional data, it may be possible to
revise or update these models if the most important exposure factors and
parameters can be identified.
Non-dietary ingestion parameters or components need to be included in existing
models.
- A model for estimating indirect dietary ingestion exposures is currently under
development (Berry, EPA) ,
l. Confirmation of this exposure measurement approach
- Biomonitoring (urine or blood) is the best way to evaluate the measurement
approach, but in order to be applied effectively the following is needed:
• Absorption rates, metabolic pathways, and kinetics for the chemical of
interest
• A method for measurement of an appropriate biomarker
• To select the sample collection timing based on the exposure timing and
uptake and elimination kinetics
• To account for other exposure pathways (inhalation, dietary)
- Biomonitoring results within an order of magnitude of estimated exposure may be
adequate.
Using a robot, modeled after a young child, may be an experimental approach
worth examining due to the difficulty in performing controlled studies with
children and potentially toxic chemicals.
- Could be used in pesticide-treated rooms, turf, etc. where child exposure would
not be allowed.
- The robot would need to have the capability to mimic child activities and
movements, contact pressures, and surface areas.
The surface could be covered with material used as skin surrogate (i.e., cadaver
skin, artificial skin, others).
- Would not provide information on non-dietary ingestion pathway .
3. Recommendations
It is suggested that these recommendations be carried out in the general order presented so that
additional data gathering can focus on the most important needs.
-a. -Identify-the most important-pesticides for-fiiture study-based on-the likelihood of-dermal
contact by children (pesticides used in homes, on lawns, and in daycare or school
settings) and potential toxicity.
20
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b. Assess current data for defining activities for young children, including NHAPS and
video analysis data for microscale activities in specific locations or situations. Identify
the most important needs for additional data gathering for young children's activities .
Identify the most important physical contact activities for additional laboratory study of
transfer parameters.
c. Develop or refine models based on the microactivity approach. Perform sensitivity
testing to identify the most important parameters for children's exposures.
d. Perform a critical evaluation of existing data and methods for dermal transfer parameters.
Identify the most important parameters requinng laboratory data gathering needed to
reduce the uncertainty in dermal exposure estimates for children. Perform laboratory
measurements to define parameter ranges for the most important pesticides and transfer
parameters.
e. Perform a critical evaluation of existing data and methods for non-dietary ingestion
parameters. Identify the most important parameters requiring laboratory data gathering
needed to reduce the uncertainty in dermal exposure estimates for children. Perform
laboratory measurements to define parameter ranges for the most important pesticides
and transfer parameters.
f. Conduct small-scale field studies for young children to determine if predicted exposures
can be confirmed through the use of biomonitoring methods. Perform studies in locations
likely to lead to the highest short-term (acute) exposures (i.e., homes or daycare centers
where pesticides are routinely applied). Test measurement methods for surface
measurements, contact parameters, and child activities that could be used in large scale
studies of dermal and non-dietary ingestion exposures for young children .
C„ Breakout Group 3: Macroactivity Approach for Assessing Dermal Exposure
1. Charge
a. Feasibility of macroactivity approach for assessing exposure
The macroactivity approach has been used extensively to assess occupational exposure of
agricultural workers. In an agricultural setting, data on worker dermal exposure (from
dosimeters such as patches or cotton garments) and data on the amount of pesticide residue on
plant foliage that is available for transfer to skin (dislodgeable foliar residue or DFR) are used to
derive transfer coefficients. These transfer coefficients are thought to be activity and crop
specific, but not pesticide specific. As a result, the transfer coefficients can be used with DFR
measurements to estimate exposure to any given pesticide under the working and crop conditions
for which the transfer coefficient was derived. The macroactivity approach has also been applied
in a residential setting for adults performing choreographed reproducible activities. By studying
a choreographed situation, the variability associated with natural human activities in a natural
residential environment is minimized and transfer coefficients potentially representing a worst
case exposure are derived. Use of this protocol requires confirmation to determine that the
-transfer-coefficients-are representative-of-high-end residential exposures-to-children .
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Because the macroactivity approach was developed for use in the homogeneous agricultural
work environment and residential studies have been limited to reproducible activities of adults,
the feasibility of the macroactivity approach for assessing children's residential exposure to
pesticides needs to be tested. The macroactivity approach may be more easily adapted for use in
assessing children's exposures in outdoor residential environments than in indoor environments.
In addition, use of this approach to assess non-dietary ingestion will require development of an
additional transfer coefficient that is not currently considered for agricultural exposures.
b. Exposure activities
One advantage of the macroactivity approach is that identification of key activities may be less
critical than with a microactivity approach. One potential method for implementing the
macroactivity approach is to identify the most significant activities of infants and children and
then collect data using simulated reproducible activities. Confirmation of the resulting transfer
coefficients is then required to relate the results of the simulated exposures to real exposures. A
second method is to collect data and develop a distribution of transfer coefficients for children in
iheir natural environment. In this case the macroactivities are likely to be characterized by the
microenvironment in which the activity takes place. For example, transfer coefficients would be
derived for infants and children at home, at school, and outside. It is hypothesized that these
transfer coefficients would be microenvironment and age specific. The need for additional
breakdown of activities (e.g., active versus resting, by time spent in a given room in the house)
would need to be tested. This second method was the focus of workgroup discussions.
c. Additional measurement methods and data requirements
In order to apply the macroactivity approach, a standard method for obtaining an aggregate
measure of residential surface concentration will need to be developed. In addition, acceptable
methods for monitoring exposure of infants and children will be required. Biological
measurements will be needed to confirm results of the assessment approach. Data relating
children's activities to dose would also be needed to identify key activities.
2. Answers to Workgroup Questions
a. Advantages of macroactivity approach
Approach has been used successfully to assess occupational exposure to
agricultural workers.
- Potentially lower data requirements over microactivity approach. Need to obtain
aggregate measure of residential surface concentration and measure of exposure.
- Could provide useful (possibly screening level) assessment in less time.
Fewer parameters may result in less correlation error.
b. Disadvantages of macroactivity approach
- Approach is not clearly feasible.
. .-Problems associated with exposing children.
Unlike the agricultural environment, the residential environment is heterogeneous.
- Unlike occupational activity patterns, children's daily activities are heterogeneous.
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Can we overcome disadvantages
- Don't know
- Recommend looking for test cases in existing data
• Minnesota pesticide study
• Environmental and exposure monitoring associated with the "1996 Methyl
Parathion ATSDR Public Health Advisory"
Key activities
- The general lack of data relating children's activities to dose, make this question
difficult to address.
- Key activities may be less critical with a macroactivity approach.
Temporal and spatial scales
Both temporal and spatial scales will be greater than for the microactivity
approach.
Scales will be age specific.
- Important time scales
• Time between application and exposure
Time of loading (exposure)
Time until bathing
Important spatial scales
Microenvironment
• Hands
• Whole body
Data needs
- Skin loading (dermal exposure)
- Aggregate measure of surface concentration available for transfer to skin
(comparable to DFR in agricultural assessments)
- Exposure duration
- Biological measurements of metabolites (dose)
Available methods
- Overall method for using this approach is available from experience in
agricultural exposure assessment.
- Methods need to be developed for measurement of aggregate surface
concentration
- Methods for study of children or child surrogates
-Gonfirmation-of approach
- Need child studies with environmental, skin loading, and dose data
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3. Recommendations
a. Identify test cases in existing data to determine if application of the macroactivity
approach for assessing dermal exposure is feasible.
b. Need agency standard for age group (or physiological development) breakdowns for use
by all researchers.
4. Additional literature and data identified during discussions
a. EPA's National Center for Environmental Assessment (NCEA) has a group that is
currently developing a standard for age-group breakdowns for children, 6 months to 21
years. Rob Elias chairs that group.
b. Literature and data from environmental and exposure monitoring associated with the
"1996 Methyl Parathion ATSDR Public Health Advisory." EPA participants in this
project may have included Drs. Elmer Akin, David Charters, J. Milt Clark, and Jon
Rauscher. In this project extensive environmental monitoring was conducted and
absorption was assessed using urinary biomarkers.
D. Breakout Group 4; Procedures for Generating Exposure Data for Children
1. Charge
a. Determine best approach for studying pesticide exposure to young children and infants
Determine what additional data and measurement methods are required to quantify
dermal and non-dietary exposure of children
Consideration of approaches included both dermal exposure (contact) and non-dietary ingestion
exposures. The age groups of concern, in terms of the need to determine (and document) if there
are actually differences in exposures (and/or body burden), include infants and young children
(e.g., 0-6 months, 6-12 months, and 1-3 years in age). Identification of the "best" approaches
requires an appreciation of how these data will be used to conduct risk assessments, and to
identify options for risk management which are both "safe" and "reasonable."
2. Answers to Workgroup Questions
a. Since you cannot intentionally expose children to pesticides or other toxic substance what
are the approaches that can be used to generate the required data?
b. What are the advantages and disadvantages to these approaches?
Several approaches were discussed, and the advantages and limitations of each were identified:
- Biomonitoring was discussed at length as providing the "best" indicator of
distributions of aggregate exposure.
Advantages: Biomonitoring integrates all routes inhalation, ingestion, and dermal
_absorption)-and incorporates all activity-patterns (relatedto-contact-and
uptake/intake). The biomarker measurements can be conducted with known
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accuracy, and provide a "benchmark to judge" and/or a "foundation to develop"
exposure (and dose) models and assessment practices.
Limitations: It may be difficult to collect urine samples from infants and young
children. There is a need for reliable collection and analysis methods, accounting
for possible interferences and difficulties in extraction of pesticidemetabolites
from urine in diapers, and to determine or estimate (e.g., from weight) urine
volumes. Some concerns have been expressed about the use of creatinine to
adjust for the volume/concentration of urine with children. There are also
difficulties in identifying the relative contribution of different routes and
pathways (environments and sources), which indicates the need to make these
measurements in conjunction with environmental and exposure monitoring.
There must be reliable and sensitive methods available to analyze for the major
metabolites of the target pesticide compounds. Interpretation of the relationship
of the metabolite concentrations to exposures requires knowledge of
pharmacokinetics and requires information (or involves assumptions) on the
timing and routes of exposures (relative to experimental settings).
Environmental (e.g., air, water, surfaces), exposure (air, dermal, diet), and
activity pattern measurements should be made at the same time as
biomonitoring. These may be done in focused (or "situational") studies (e.g.,
post-application), or in population probability-based surveys (stratified by usage),
and/or under simulated (experimental/controlled) conditions.
Advantages: This combination provides evidence of the "total" (aggregate)
exposure under the conditions of study, as well as information to
estimate/evaluate the relative contributions of each route, and the influence of
activity patterns (e.g., diary reports and/or videography) on the frequency and
magnitude of exposures .
Limitations: These studies are usually only able to observe/measure
concentrations and exposures in a limited number of locations. It is difficult, both
in terms of cost and feasibility, to collect samples of environmental media
concentrations from sites which are "representative" of those likely to be
contacted by the study subject (e.g., stratification of air and surface concentrations
and availability).
Passive dosimetry (body suit, patches) can be used to measure/estimate dermal
exposure under specific conditions and time periods (e.g., post-application).
'Advantage: -The-dosimeter-can-be calibrated-to^estimate-the'proportion-of the
suit/patch measurement (concentration/loading) that would be transferred to the
skin, and the portion of this that would be absorbed (rate). Patches can be done in
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conjunction with biomonitoring studies (without interfering with the exposure and
absorption). It might be feasible to use patches with infants.
Limitations: The (structured) activities of adults then assumed to represent those
of children (unstructured) as they relate to calculation and use of a transfer
coefficient (cm2/hr). It can be difficult to extrapolate from patches to other skin
surfaces, both in terms of differences in exposures and the transferability and
retention of the patch relative to skin.
Fluorescent tracer methods can be used with children.
Advantages: this provide quantitative estimates of dermal exposure (qualitative
for hand-to-mouth).
Limitations: There may be some masking of surfaces; difficult to obtain
measurements from cylindrical surfaces (e.g., arms and legs). Differences
between the characteristics of the tracer and the target chemical may result in
differences in the distribution of the materials in the home, and in transferability
to the skin.
Dermal wash/rinse/wipe methods can be conducted with children for easily
accessible surfaces (e.g., hands). There were some concerns about the effects of
different solvents (isopropyl alcohol) on extraction efficiency or sample stability
Advantages: This provides a measure of the dermal loading/concentration on the
hands which is important for determining the potential for exposures associated
with mouthing events. The hands are frequently uncovered and are the point of
contact (exposure) with surfaces, so that a hand wipe/rinse is useful to say if there
is evidence of any dermal exposures. In controlled studies, this can be used to
assess recovery of residues from the skin.
Limitations: The sample is usually taken at a single point in time, and provides an
indication of the portion of the previous exposures which have not been absorbed
(or removed from the skin). It is probably a better indicator of the environmental
concentrations on surfaces contacted by the child than of the absorbed dose.
a. What type of data currently exist for children to evaluate dermal exposure methods or
models? From NHEXAS, NHAKES, other field studies?
There was only limited discussion of the currently available field studies. (Some of this had been
discussed in a previous workshop on Activity Patterns). The Minnesota Children's Pesticide
"study (component-'of"the NHEXAS study) provides concurrent-biomonitoring,-exposure (air,
diet, dermal), environmental (air, water, soil/dust), and activity patterns (self-reporting, limited
videography) for a sample of children, ages 3-12, selected with an emphasis on households w ith
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more frequent indoor insecticide use. NHANES-III provides reference ranges for pesticide
metabolites in adult urine samples (not intended to be a representative probability sample). Plans
for NHANES-IV are to collect and analyze urine samples from children ages 6 and older.
b. What additional data are needed?
- Concurrent biomonitoring and exposure/environmental/ activity monitoring
studies are needed for infants and young children. This requires some
development of methods for:
Biomonitoring -- both laboratory and field sampling (i.e.. for collection
and analysis of urine samples);
• Screening techniques which are reliable, sensitive, and low cost. For
example, the identification of exposed populations to OP pesticides would
be improved by improving the detection limits for alkyl phosphates (from
~25ppb to ~5 ppb).
Realistic estimates of the ranges of aggregate exposure, as determined from
biomarker data, are needed:
• to provide risk managers with a determination of whether there is an
immediate need to take actions to reduce exposures,
to determine if the current screening-level assessments (SOPs) are
"realistic" in representing potential exposures in the aggregate, and
• to provide a basis for developing and evaluating (validating) improved
models of aggregate exposure (and dose).
There is a need for more data on the activities/behaviors of infants (e.g., 0-6
months) and young children (e.g., crawling, 6-12 months).
c. Can we evaluate dermal models? What is the best way to do it?
- Dermal exposure. The basic information needed to develop and evaluate models
of dermal exposure could be developed in experimental studies/settings. This
allows one to control/modify the factors relating to exposures and focus on the
dermal route.
Advantages: This approach provides an understanding of the factors which
influence dermal exposure.
Disadvantages: There is a need to have marker compounds that can be safely used
with children, since there are physical and flexibility differences between children
and adults. There are possible adjustments that can be made for these differences
when detailed biomechanics measurements can be collected for a sample of
children and applied to the exposures of adults. Another approach suggested was
the possibility of linking the activities of unexposed children to that of a robot in
-an-exposure chamber.
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- Dermal dose. Consideration of dermal exposure in the context of its contribution
to aggregate exposure and risk also requires determination of the relative
bioavailability and uptake/absorption of pesticides via the dermal route. A
distinction was made between the potentially exposed surface area (total area of
hand, ~400 cm2) relative to the likely contact area (-55 cm2) and the implication
of this for dermal loading and mouthing-related ingestion (area of fingers < total
hand). Information is needed on:
the transfer of materials from surfaces to the skin from repeated contacts
(effects of increasing dermal loading and decreasing surface loadings);
• extraction efficiency of the mouth (i.e., saliva and sucking/ licking motion)
for both residues and particles (with residues).
- Indirect (non-dietary) ingestion. There was some discussion of how to
distinguish the contributions (to aggregate exposure) of dermal and ingestion
routes. One approach is to identify a model compound which would have a
different metabolic profile following oral and dermal dosing, and metabolites
which could be measured in urine.
3. Recommendations
a. Perform biomonitoring studies to provide a realistic estimate of the distribution of
aggregate "exposures" for children, These studies have immediate value in determining the
likely ranges (including "high-end") of exposures which may be associated with pesticide use.
For purposes of determining the relative contribution of different routes, pathways, contact
activities, and sources to aggregate exposures it is important to include environmental and
exposure monitoring (concurrent with biomonitoring). The major microenvironments of interest
include residential (indoor/outdoor),daycare, and school settings (and possibly other locations
where there is limited mobility, e.g., hospitals). The age groups of special concern include 0-6
month, 6-12 month, and 1-3 year old children. These studies could be done either as field studies
or experimental studies. Field studies include both probability surveys and "opportunistic"
studies following application events. Surveys may be stratified by usage and time, to provide
adequate representation of the more "highly exposed" individuals and time-periods.
Time-periods relevant to use-events include both the immediate post-application time frame and
extend for two-to-three weeks thereafter. Experimental (controlled) studies conducted in test
chambers, or outdoor locations, are useful to address mechanistic questions.
b. Exposure/dose models need to be simple, must be capable of representing "high end"
exposures {highest priority need}, must be realistic (within some margin of error), and must
specifically address children's acute and chronic exposure (age-related exposure,
activity/behavior). Exposure models should be evaluated using biomonitoring measurements.
An immediate need is to evaluate the acute exposures predicted by the EPA/OPP's current SOPs.
These are a series of scenario-based "models" (set of default assumptions) for various types of
-residential-pesticide-applications. -They-were developed-to-meet-a short term-need,-and were
based on information that was currently available as a consensus (based on professional
judgement). Major uncertainties in these include the frequency (and timing) of hand-to-mouth
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activities, the use of transfer factor/coefficients for children, and the availability/transferability of
residues from surfaces.
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APPENDIX A
AGENDA
7:45 Registration
8:00 Introduction
NERL dermal exposure research program
Conceptual model for dermal exposure process and exposure assessment
methodologies
EPA literature review
Charge to breakout groups
10:00 Breakout groups
1. Pesticide concentrations in exposure media and scenarios for exposure
2. Single event (microactivity) approach for assessing dermal exposure
3. Integrated activity (macroactivity) approach for assessing dermal
exposure
4. Procedures for generating exposure data for children
12:00 Lunch
1:00 Breakout continued
2:30 Report on results of breakout discussions
4:00 Summarize most significant uncertainties and data gaps associated with use of
measurements to assess dermal exposure
5:00 Adjourn
A-l
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APPENDIX B
LIST OF PARTICIPANTS
Qrpup 1
Edwin Furtaw
EPA/ORD/NERL-LV (EPA Facilita
Marcia Nishioka*
Battelle - Columbus (Rapporteur)
David Camann*
SWRI
JefT Dawson
EPA/OPP
John Deprospo
AgrEvo
Chris Fortune
ManTech
Dennis Klonne
Toxicol. Expos. Assess. Services
Bob Lewis
EPA/ORD/NERL-RTP
Charles Rodes*
RTI
Dan Stout
EPA/ORD/NERL-RTP
John Streicher
EPA/ORD/NERL-RTP
Group 2
Kent Thomas
EPA-NERL (EPA Facilitator)
James McDougal*
Wright Patterson AFB (Rapporteur)
Michael Dellarco
EPA-NCEA
Michael Firestone
EPA-OPPTS
Zhishi Giuo
EPA-NRMRL
Larry Hall
EPA-NHEERL
Marc Rigas
EPA-NERL
Leah Rosenheck
Novartis
Susan Hunter Youngren
Novigen Sciences, Inc.
Valerie Z art an an*
EPA-NERL
Group 3
Elaine Cohen Hubal
John Kissel*
Jeff Evans
Annette Bunge
Jim Riviere*
Frank Selman
Mark Boeniger*
Curt Dary
Muhilan Pandian
Rob Elias
NERL/ORD (EPA Facilitator)
University of Washington (Rapporteur)
OPP
Colorado School of Mines
North Carolina State University
Novartis
NIOSH
NERL/ORD
risksciences.com
NCEA/ORD
B-l
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Group 4
Jim Quackenboss
Bob Krieger*
Gerry Akland
Jeff Driver
Monte Eberhart
Natalie Freeman*
Steve Knott
Marsha Morgan
Bill Nelson
A1 Nielsen .
Margaret Stasikowski
Nancy Wilson
* External peer reviewer
NERL/ORD (EPA Facilitator)
University of California, Riverside (Rapporteur)
RTI
RiskSciences
BayeT Corp.
EOHSI
NCEA/ORD
NERL/ORD
NERL/ORD
OPP
OPP
NERL/ORD
B-2
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APPENDIX C
DERMAL EXPOSURE RESEARCH QUESTIONS
(focused on children's exposure to pesticides due to contact with contaminated surfaces)
Transfers from Source to Exposure Media
What are the significant sources of pesticides on contaminated surfaces that lead to dermal
exposure?
• What are the scenarios for transfer of contamination from the source to an environmental
medium and then to a surface or object (e.g. track in)?
• What measurement methods and models are available to relate sources of contamination to
contamination on surfaces and objects?
Exposure Media
• What are the concentrations on surfaces and objects (distinguish between total concentration
and concentration available for transfer to skin)?
What are the characteristics of the contamination (e.g. deposition form, physicochemical
properties)? How do these characteristics vary with time?
What are the characteristics of contaminated objects and surfaces?
• What methods and models are available to measure and predict contaminant concentrations on
surface and objects?
Transfer from Exposure Media to Skin
What are the major parameters that determine fraction and rate of mass transfer from the
exposure media to skin?
• How do characteristics of the skin affect mass transfer?
• How do characteristics of contaminated objects and surfaces affect transfer?
• How do the characteristics of the contaminant and the material being transferred affect
transfer?
• How does the type of contact affect mass transfer (contact pressure, motion, frequency,
duration)?
• How do environmental conditions affect mass transfer?
• What methods and models are available to measure and predict mass transfer rates and
-transferable fraction?
C-l
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• How can measurements of transferable fraction and mass transfer be used to estimate
exposure?
Contact Activities
Which objects and contact events contribute significantly to dermal exposure?
What is the frequency and duration of sequential contacts between various skin surfaces and
exposure media?
• What is the spatial distribution of contact events over the surface of the body?
What activities contribute to removal of contaminant from the skin (e.g. hand washing,
mouthing)?
• What are the activity patterns of susceptible subpopulations (children)?
What methods are available for quantifying and characterizing (e.g., contact pressure and
motion) contact activities?
Dermal Loading
What are the mechanisms (pathways) by which chemicals can be loaded onto the skin
surface? What are the important parameters for characterizing these pathways?
What are the mechanisms by which chemicals can be lost from the skin surface (e.g.,
mouthing)? What are the important parameters for characterizing these losses?
How can measurements of dermal loading be used to estimate exposure (applied dose)?
• How can the variation in dermal loading over time and body region be assessed?
What measurement methods are available to assess the contaminant adhering to skin surfaces?
• What models are available to predict dermal loading and to relate dermal loading
measurements to exposure?
Non-dietary Ingestion (mouthing of skin surfaces contaminated by contact with contaminated
surfaces and objects, and direct mouthing of contaminated objects and surfaces)
What activities are important for characterizing non-dietary ingestion of pesticides?
• What models and measurement methods are available to estimate and predict exposure to
pesticides by non-dietary ingestion?
C-2
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Dose/Uptake
What are the major parameters that determine uptake of pesticide residues and residues bound
to particles through skin?
• How do characteristics of the skin affect uptake?
• How do the characteristics of the contaminant affect uptake?
• How can biological monitoring be used to estimate dose due to dermal exposure?
• How can biological measurements be disaggregated to estimate exposure by route?
What models are available to relate dermal loading of and exposure (applied dose) to particles
and residues to uptake and absorbed dose?
C-3
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APPENDIX D
REVISED BIBLIOGRAPHY
Dermal Exposure Workshop Bibliography
Part 1: Peer Reviewed Literature
Archibald, B. A., K. R. Solomon, et al. (1994). "A new procedure for calibrating the video
imaging technique for assessing dennal exposure to pesticides." Arch Environ Con tarn
Toxicol 26(3): 398-402.
Archibald, B. A., K. R. Solomon, et al. (1995). "Estimation of pesticide exposure to greenhouse
applicators using video imaging and other assessment techniques." Am Ind Hve Assoc J
56(3): 226-35.
ASTM (1994). Standard Practice for Collection of Floor Dust for Chemical Analysis
ASTM (in press). Standard Practice for Collection of Dislodgeable Pesticide Residues from
Floors, American Society for Testing and Materials, Committee D-22 on Sampling and
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Derma] Exposure Workshop Bibliography
Part 2: Agency Reports and Other Publications
Bergeron, V., C. Norman, et al. (1997). Workshop on Postapplication Exposure Assessment —
Final Report. Toronto, Canada.
Budd, W. T., J. W. Roberts, et al. (1990). Field Evaluation of a High Volume Surface Sampler
for Pesticides in Floor Dust, EPA. EPA/600/S3-90/030.
Camann, D., Majumdar TK, Harding HJ, (1995). Comparison of Salivary Fluids with Respect to
Pesticide Transfer Efficiency from Carpet to Saliva-Moistened Hands, EPA, SwRl,
Mantech.EPA Contract Number 68-DO-)106; SwRI contract number 01-7131; ManTech
P.O. 96LP0047 Task 003.
Camann, D., Harding HJ, Geno PW, Agrawal SR (1996). Comparison of Methods to Determine
Dislodgeable Residue Transfer from Floors, RTP, NC, National Exposure Research
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Camann, D. E., B. Curwin, et al. (1998). Dermal Exposure to Groundboom-Applied Pesticides.
1SEE/ISEA Conference, Boston, MA.
Camann, D. E., A.Y. Yau (1998). Distributions of Pesticides. PAH and PCB Coeeners in Lone
Island Carpet Dust. ISEE/ISEA Conference, Boston, MA.
Camann, D. E. (1998). Results summary from experiments 6.1 and 6.2 of WA ID-76 task 3.
Camann , D. (1998). Protocol to Determine Dermal Transfer Efficiency From Used Cut-pile
Carpet and Dry and Wetted Palms, EPA. Experiment 6.2 of Work Assignment 11-47.
Chuang, J., Gordon SM, Roberts JW, Han W, Ruby MG (1995). Evaluation of HVS3 Sampler
for Sampling Polycyclic Aromatic Hydrocarbons and Polychlorinated Biphenyls, EPA.
EPS/600/SR-94/188.
Fortmann, R. C., L. S. Sheldon, et al. (1993). Field Evaluation of Methods to Monitor Potential
Exposure of Young Children to Pesticides in the Residential Environment, EPA / RTI
Fortune, C. (1997). Round-Robin Testing of Methods for Collecting Dislodgeable Residues
from Carpets, EPA. EPA/600/R-97/119.
Fortune, C. (1997). Evaluation of Methods for Collecting Dislodgeable Pesticide Residues from
Turf, EPA
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Freeman, N. C. G. and R. Edwards (1998). Hand surface area measurements.
Freeman, N. C. G. (1998). Data from NHEXAS Minnesota Children's Pesticide
Study.
Fieeman, C. G. (draft). Exposure Assessment for Children: Availability of Data to Estimate
Risk, Office of Research and Development, U.S. EPA
Geno, P. W., A. Yau, et al. (1998). Using Artificial Saliva to Estimate Pesticide Exposure in
Small Children: Hand Wipe and Skin Monitoring Methods for Dermal or Non-dietary
Ingestion, EPA, SwRJ, ManTech
Hsu, J. P., D. E. Camann, et al. (1990). New Dermal Exposure Sampling Technique.
EPA/AWMA International Symposium "Measurement of Toxic and Related Air Pollutants",
Raleigh, NC.
Nishioka, M. G., H. M. Burkholder, et al. Development of Analytical Methods for Lawn-
Applied Pesticides in House Dust
Nishioka, M., C. Hines, et al. (1997). Measurement of Toxic and Related Air Pollutants-
Comparison of Commercial vs. Homeowner Application for Transport of Lawn-Applied
Herbicide 2.4-D Into Homes. Proceedings of a specialty conference; Air and Waste
Management Association EPA/NERL.
Nishioka, M. G., H. M. Burkholder, et al. (1997). Simulation of Track-In of Lawn-Applied
Pesticides from Turf to Home : Comparison of Dislodgeable Turf Residues with Carpet Dust
and Carpet Surface Residues, EPA. EPA/600/R-97/108.
Nishioka, M., J. Menkedick, et al. (1998). Intrusion of Lawn-Applied 2,4-D into the Home:
Strategies for Assessing Transport and Role of Activity Patterns in Exposure. Chapel Hill,
NC, EPA and Battelle Memorial Institute
Roberts, J. W. and M. G. Ruby (1989). Development of a High Volume Surface Sampler for
Pesticides in FIoot Dust, EPA. EPA/600/S4-88/036.
Roberts, J. W., W. Han, et al. (1996). Evaluation of Dust Samplers for Bare Floors and
Upholstery, EPA. EPA/600/R-96/001.
U.S. EPA. (1992). Dermal Exposure Assessment — A Literature Review. Las Vegas, Nevada,
Office of Research and Development, U.S. EPA. EPA 600/X-92/002.
U.S. EPA. (1992). Dermal Exposure Assessment: Principles and Applications. Washington,
DC, Office of Research and Development, U.S. EPA. EPA/600/88-91/01 IB.
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U.S. EPA. (1993). Protocol for Dermal Assessment: A Technical Report. Las Vegas, Nevada,
Office of Research and Development, U.S. EPA. EPA/600/X-93/005.
U.S. EPA. (1993). Report from the workshop on the development of post-application exposure
monitoring and assessment guidelines for pesticides and consumer use products in residential
environments., Office of Research and Development
U.S. EPA. (1994). NHEXAS presents a workshop to identify optimal dermal exposure sampling
methodologies. Research Triangle Park, Atmospheric Research and Exposure Assessment
Laboratory
U.S. EPA. (1997). Evaluation of Methods for Collecting Dislodgeable Pesticide Residues from
Turf, EPA. EPA/600/R-97/107.
U.S. EPA. (1997). Development of Analytical Methods for Specific Lawn-Applied Pesticides in
House Dust, EPA. EPA/600/R-97/110.
U.S. EPA. (1997). Exposure Factors Handbook. Washington, DC, Office of Research and
Development, U.S. EPA. EPA/600/P-95/002Fa.
U.S. EPA. (1997). Workshop Report on Dermal Exposure Assessment: Review Draft (Do not
cite or quote). Washington D.C., Office of Research and Development. EPA/600/R-98/001.
U.S. EPA. (1998a). Assessment of Time-Motion Videoanalysis for the Acquisition of
Biomechanics Data.in the Calculation of Exposure to Children. Washington, DC, Office of
Research and Development, U.S. EPA. EPA/xxx/R-98/xxx.
U.S. EPA. (1998b). Laboratory and Field Methods to Establish a Dermal Transfer Coefficient
for Residential Exposure Monitoring. Washington, DC, Office of Research and
Development, U.S. EPA. EPA/xxx/R-98/xxx.
U.S. EPA. (1998). The role of child behavior and activities in determining exposure to
xenobiotics. Child behavior patterns: An analysis of the data. Washington, DC, Office of
Research and Development. EPA/600/X-98/005.
D-l 1
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APPENDIX E
U.S. EPA SEPTEMBER 1998 DERMAL EXPOSURE WORKSHOP
SUMMARY OF LITERATURE REVIEW FOR MEASUREMENT METHODS AND
RESULTS
Surface Measurements
¦ Extractable Residues
¦ Extractable Dust/Soil
¦ Transferable Residues
¦ Transferable Dust/Soil
Dermal Loading Measurements
¦ Dust/Soil Adhesion
¦ Whole Body Dosimeters and Hand Wipes
Non-Dietary Ingestion
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Method
Results
Surface lCleasurements
Extractaiile Residues Following Application
Chensene.1998
The purpose of this study was to measure surface concentrations of
chlorpyrifos following broadcast or aerosol applications.
Deposition samples were collected by applying double-layer 12-ply
cotton 7.6 x 7.6 cm gauze pads to randomly selected areas of carpet
before application.
After broadcast treatment carpet deposition sample loadings ranged from 19.7 to
22.3 ^g/cm*; furniture deposition sample loadings ranged from 0.003 to 0.004
jig/cm'. After aerosol treatment carpet deposition sample loadings ranged from 2.7
to 2.9 /jg/cm'; furniture deposition sample loadings ranged from 1.79 to 1.83
^g/cm'; wall deposition sample loadings ranged from 0.06 to 0.09 /ig/cmJ.
Fenskfc
Commercial broadcast application of chlorpyrifos (0.48 to 0.5% in
aqueous soiiition) was performed at three residential and one olTice
location. Deposition samples were collected on treated surfaces in
three of the four study sites and on untreated surfaces for three of
the four study sites. Deposition samples were collected on 100 cm2
aluminum foil squares.
1
Mean deposition loadings measured on treated surfaces immediately after
application ranged from 4.7 to 24 ^g/cm1 (mean 13.6 /ig/cm1) at one site; 1.2 to 5.1
Aig/cm' (mean 3.2 ^g/cm1) at a second site; and 0.7 to 3.7 /ig/cmJ (mean 1.9
Mg/cm1) at a third site. The variability across sites, even when using similar
application methods, shows the importance of measuring actual deposition for
comparability across studies.
Nlshloka. 1996
2,4-D and dicamba were professionally applied to lawn turf to
examine dislodgeable residue, track-in, and temporal changes.
Applied turf levels arc reported here.
Turf levels of applied herbicides were 26.7 * 10.0 mg/m1 for 2,4-D and 1.7 ± 0.9
mg/m2 for dicamba.
Ross. 1990
Home foggers were activated in hotel rooms with carpeted floors,
most fumitfire removed, under controlled conditions of access and
ventilation. Deposition samples were collected on the floor at four
locations td measure chlorpyrifos and allethrin. Deposition samples
were collected on 400 cm2 aluminum sheets and on 12-ply gauze
pads placeci in dosimeters with 23.8 cm1 exposed surface area.
Chlorpyrifos deposition measured on aluminum sheets ranged from 0.20 to 4.75
jig/cm1 across the four different locations and six different treated rooms. The
largest range within one room was 0.20 to 1.18 ^g/cm1 in opposite comers of the
room. Chlorpyrifos deposition measured on gauze pads (placed next to the
aluminum sheets) ranged from 0.47 to 4.75 /ig/cm1. The largest range within one
room 0.47 to 4.75 nfjcm1. Deposition rates measured with gauze pads were usually
higher than rates measured with aluminum foil, with ratios ranging from 0.76 to
8.8; typically the ratio was near 1.5 to 2. Allethrin deposition ranged from 0.10 to
0.40 Mg/cm2 as measured with aluminum sheets, and from 0.14 to 0.31 Mg/cm1
measured with gauze pads.
E-2
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Method
Wright, 1984
This study measured deposition of chlorpyrifos and Diazinon
following crack and crevice application. Tests were performed in
12 nonoccupied dormitory rooms. Aerosol or emulsion application
of the pesticides at 0.5% or 1% concentrations were made with
commercial application equipment into cracks and crevices to
simulate treatment for cockroaches. Pie plates were placed on a
table in the rooms during pesticide application and were
immediately samples after the application was finished and one day
post-application.
Residues were measured by placing stainless steel and formica
plates on a table in the center of the room. Plates were sampled,
using the wipe procedure, to recover pesticide residue at selected
post-application intervals. Wipe samples were collected from the
stainless steel and formica plates using cotton balls saturated with 10
mL of isopropanol. Two wipe samples were collected from an 80
cm2 area. Wipe samples were collected at 1,3,7,14, and 42 day
intervals.
Results
Diazinon was measured on the pie plates at 20 to 30 ng/cm2 immediately after
application and was not detected one day later. Chlorpyrifos was measured at 100
ng/cm1 immediately alter application; the loading decreased to I to 2 ng/cm1 one
day after application. No difference in deposition was observed between the aerosol
and emulsion applications.
Chlorpyrifos residues on the steel and formica plates ranged from 1,000 to 3,400
ng/cmJ on the day of application, decreasing to 50 to 130 ng/cmJ 7 days post-
application and 20 to 100 ng/cmJ 42 days post application.
Diazinon residues ranged from 700 to 1,600 ng/cm3 on the day of application,
decreasing to 290 to 660 ng/cmJ 7 days post-application and 310 to 370 ng/cm1 14
days post application
Camann ana Harding. 1996
Broadcast application by professional pest control applicator;
applied according to label instructions; ventilation for 2 hrs after.
Extractable residue measured using deposition coupons collected on
day of application.
Flooring
Active Inered.
Floor Cone
plush nylon
Chlorpyrifos
13,500
carpet
plush nylon
Chlorpyrifos
19,800
carpet
loop polyethy-
Chlorpyrifos
10,600
ene carpet
plush carpet
Chlorpyrifos
5,800
(used)
Piperonyl Out.
5,760
PyTClhrin 1
555
Sheet vinyl
Chlorpyrifos
8,000
(new)
Piperonyl Rut.
7,600
Pyrethrin I
1,200
(ng/cm2)
Others also reported
-------
Method ;
Results
Currle. 1990
-A commercial air sprayer was used to apply insecticides tu the
floors of seven offices (3 with carpet sprayed with Diazinon, three
with carpet sprayed with chlorpyrifos, and one office with a vinyl
floor sprayec) with bendiocarb).
-Air samples were collected prior to application, during application,
and at intervals of up to 10 days post-application.
-Surface deposition samples were collected by placing aluminum
pans on the floor and at selected heights above the floor and
removing them for extraction at intervals over the first 24 hours
post-application.
-Wipe samples were collected from the floor aluminum pans and
from furniture in the offices at intervals of 1 - 2 hours, 24 hours, and
48 hours post-application. Two isopropanol-soaked gauze pads
were used to wipe an area of 33 cm2, with the pads drawn across the
surface in both directions
Ą
Diazinon Results:
-Deposition on aluminum plates ranged from 0.4 to 15 ng/cm1. Concentrations on
suspended plates generally had higher amounts 24 hr post-application than they did
1 - 2 hr post-application.
-Wipe samples measured loadings ranging from 13 to 38 ng/cm2.
Chlorpyrifos Results:
-Deposition on aluminum plates ranged from 0.24 to 3.16 ng/cm2. Concentrations
on suspended plates generally had higher amounts 24 hr post-application than they
did 1 - 2 hr post-application.
-Wipe samples measured loadings ranging from <0.3 to 5.9 ng/cm2.
Bendiocarb Results:
-Deposition on aluminum plates ranged from 2.1 to 3.1 ng/cm1.
-Wipe samples measured loadings ranging from 11 to 25 ng/cm2.
R-5
-------
Method
Results
Extractable Dust/Soil
Simcox, 1995
Pesticide levels found in the soil of agricultural homes was
compared to nonagricultural homes. Soil samples were taken from
children's outdoor play areas (26 cm x 26 cm). The top 0.5-1.0 cm
of soil was taken and extracted to target four commonly used
pesticides: phosmet, chlorpyrifos, azinophosmethyl, and ethyl
parathion. The samples were sieved through 425 ^im mesh and
desiccated. The samples were then pre-wet with 400/^L distilled
water and 50 mL acetone, then sonicated.
Household (lust samples were collected with a HVS3 vacuum and
extracted to target the same four pesticides. The target sample
weight was 5 g ; samples were sieved through a 150 ^m mesh sieve.
r
Organophosphorous pesticide concentrations in soil (mean, ng/g):
Ag families Reference families
azinophosmethyl 60 <32
phosmet 26 <7
chlorpyrifos 17 It
ethyl parathion <34 <34
Organophosphorous pesticide concentrations in household dust (mean, ng/g)
Ag families Reference families
azinophosmethyl 1870 330
phosmet 2080 227
chlorpyrifos 429 168
ethyl parathion 365 76
Significantly higher levels of pesticides were found in the homes of agricultural
families. Much higher levels were found in household dust (see below), where
chemicals are not degraded or dispersed by environmental factors.
Bradman, 1991
This pilot study was to assess the level of pesticide contamination in
rural children's home environments. Carpet dust was sampled with
an HVS3; linoleum floors were sampled with a modified canister
vacuum and hose. The carpet dust samples were passed through a
150 ^m sieve and weighed. Bare floor dust samples were collected
on a pre-weighed filter, which was re-weighed aflcr sampling.
Diazinon was detected at four farmworker homes, with loading that ranged from
31-149 Mg/mJ. This pesticide was detected in two non-farmworker homes, with
loadings of <2^g/m2 at the daycare center and up to l4jzg/mJ in the other home.
Chlorpyrifos was detected in four farmworker homes and one non-farmworker
home. The loading in the farmworker homes ranged from not detected to 14 ng/m1.
The loading in the non-farmworker home was up to 2 f/g/m3. Chlordane and t-
nonachlor were detected in the daycare center and Fresno home at 1 to 3 ug/m3.
Most other pesticides detected in housedust were well below 1 ^g/mJ.
-------
Method
Results
Budd.1990
The purpose of this work was lo field test the H VS2 to provide
preliminary data on the amount and characteristics or dust in
residences, die concentration of 30 pesticides in house dust, and to
validate the methodology of the HVS2 in a nine-home pilot study.
The surface loading was calculated by dividing the lotal mass of the
pesticide by the area samples (ng/m1)
An average of 11.8 target pesticides were identified in the floor dust in the nine
sites. The highest concentrations in ng/m2 were found for o-phcnylphenol
(32,000), Diazinon (57,000), chlorpyriros (190,000), chlordane (184,000), cis-
pcrmclhrin (21,000), and tTans-permethrin (26,000). The range Bcross nine homes
for a few of the 30 pesticides were: for chlorpyrifos 260 lo 190.000 ng/m2; for
chlordane 225 to 184,000 ng/m2; dieldrin 32 to 7400 ng/m2; for Diazinon 22 lo
57,000 ng/m2; and for propoxur460 lo 42,000 ng/m2. The only relationship found
wilh any physical or socioeconomic variables was between the number of pesticides
and the age of ihe home.
Roberts and Rubv. 1989 (Method development)
The high volume surface sampler (HVS2) was evaluated as a
method to collect house dust (including semi-volatile organics).
The goal was to have a known and reproducible removal rale of
dust; relatively constant efficiency at different loadings of dust;
similar size distribution of retained material which would slick to a
child's skin/hand; and collect/extract the low and medium volatility
organics expected to be found on dust particles. The HVS2 was
tesied with pesticide-inoculated dusts on three different surfaces at
different surface loadings, with rfifTerent static pressures.
The static pressure was found to be the best measure of appropriate height for the
nozzle on carpets. When operated al the defined optimal settings, the fine materials
(less than 150 fim) collected are approximately 6% of Ihe total load of a standard
lest dusi and 30% of the fine materials in the test dusl. Collection efficiency on bare
floors was greater than 90%. Did not evaluate size distribution of material which
would stick to a child's hand.
E-7
-------
Method
Roberts. 1996 (Method development)
This project involved testing three devices (HVF3, HVTS, BRMCS)
in an attempt to find a reliable method for measuring dust on hare
floors and upholstery. The collection efficiencies of three new
devices were tested along with the accepted method of the High
Volume Small Surface Sampler (HVS3). The new devices are the
High Volume Tripod Sampler (HVTS), the High Volume Furniture
Sampler (HVFS), and the Baltimore R&M Cyclone Sampler
(BRMCS). The exposure media in this experiment were bare floors,
upholstery, and nigs (plush and level loop). The dust loadings used
in this study were
I) Bare floors: two loadings of 0.1 and 0.5 g/m1 dust (from
home vacuum cleaners) to represent light and heavy; applied to
bare floor with a baker shaker. Dust was first sieved with a mesh
screen so that the particles were <150 nm.
2) Upholstery: one gram of fine couch dust (two loadings of
2.5 and 5.6 g/m2) was embedded in the face and vacuumed from the
surface during testing.
Results
Collection Ffficiencies of the Dust Samplers:
HVS3
1IVTS
HVFS
BRMCS
bare floor
85-R7%
R4-85%
84%
85%
nigs:
plush
67%
62%
44%
level loop
69%
66%
61%
upholstery:
velvet
NA
NA
87-90%
72%
flat
NA
NA
89-91%
87%
The four devices tested were equally effective in collecting house dust from bare
floors. The HVFS was efficient in collecting dust from upholstery, and can be used
alone or as an attachment to the HVS3. The HVTS and the BRMCS are lower in
cost than the IIVS3 but have limitations when used on rugs and upholstery.
r>8
-------
Method
Camann anil Yau. 1998
Pesticides, PAHs, and PCBs were measured in dust samples
collected from >140 Long Island homes of women enrolled in
Breast Cancer Study. Carpet dust collected using the HVS3; <150
/^m dust fraction extracted and analyzed.
Results
Concentrations (ue/e)
% Delected
SO1" Percentile
90'" Percentile
Max
Aldrin
8
<003
<0.14
0 98
Atrazine
0
<002
<0 07
<0.30
BeU-miC
0
<0 01
<0.75
<4 8
Alpha -chlordane
91
0.20
092
6 2
(jamma-chlordane
94
026
14
8 5
Dielrtrin
24
<0 07
042
6.7
4,4'-DDD
19
<003
0.12
14
4,4'-DDE
62
0.04
023
0 86
4,4-UDT
75
0.15
1.4
46
Heptachlor
44
<0 04
0.28
1.2
Heptachlor Rpnxide
6
<002
<006
006
1 laxachlnrobcnzenc
1
<0.02
<0 06
0 31
Lindane
0
<003
<0.27
<76
Methonychlor
71
0.26
2 4
31
trans-Nonachlof
85
0.13
0.63
4 3
Oxychlordane
1
<0 05
<048
Oil
Chlordane Loadines (ue/m1)
Alpha-Chlordane
0.12
1.5
22
Gamma -Chlordane
0 18
1.9
31
Heptachlor
<003
0.28 .
7
transnonachlor
0.08
0 96
13
Data from the Long Island Study were compared to results from Childhood
Leukemia Study (n=362) in nine midwestcm states. Median pesticide dust
concentrations were similar in both studies for most pesticides. The percentage of
results above 0.1 ng/g was higher in Long Island for most pesticides. Maximum
concentrations were higher in the midwest. Median loadings (us/m2) were about
two times higher for most pesticides in the midwest homes.
B 9
-------
Method
Results
Transferable Residues
Geno. 1996
Hands arc pressed onto aluminum foil spiked with pesticides. Foil
allowed to dry.
Transfer efficiency from foil to hands of appox. 85% for chlorpyrifos and pyrethrin
1.
Gurunathaii. 1998
Chlorpyrifos residues measured after pesticide application. Surface
samples collected with LWW wipe method (filter material wetted
with methanol and hexane, S passes over 100 cm2). Plastic toys and
plush toys extracted with hexane.
Surface wipes: One-wipe samples had peak of 43 ng/cm1 on dresser top 36 h post-
application with subsequent decrease over time. Multiple wipe samples increased
through 72 h. Surface of plastic toys had mean residue of 11,500 ng/cm2 with peak
at 1 week post-application. Plush toys had mean residue of 15,000 ng/cm1 with
peak 2 weeks post-application.
NOTE: Toy extraction method may not represent transferable residue.
Chensene. 1998
The purpose of this study was lo measure surface concentrations of
chlorpyrifos following broadcast or aerosol applications. Surface
wipe samples were collected with surgical gauze pads sprayed
lightly two times with distilled water. An area nf 100 cm1 was
wiped with 3 strokes. A second pad was used in the same area with
the wipe performed at a 90s angle to the first wipe. Carpet and
other surface samples were collected using this wipe procedure to
measure transferable residue.
Transferable carpet residue measured after broadcast application was 143 lo 186
ng/cm2 one hour after application decreasing to 19 to 24 ng/cm12 days post-
application and 6 ng/cm2 7 days post-application.
Carpet residue measured after aerosol deposition was 98 to 131 ng/cmJ one hour
after application decreasing to 10 to 15 ng/cm2 2 days post-application and 1 to 2
ng/cm2 7days post-application. Differences in ventilation during the 7-day period
did not produce large effects in dislodgeable residue.
n io
-------
Method
L
Results
Fenske. 1991
Commercial broadcast application of chlorpyrifos (0.48 tn O.S% in
aqueous solution) was performed at three residential and one office
location. Wipe .samples were collected at eight times post-
application. Three replicate samples were collected at each location
to assess method and residue variability. Wipe sampling was
performed using a modification of the OSHA procedure. Iliree
strokes across a 100 cm1 were made with a 7.5 * 7.5 cm surgical
gauze pad, followed by three strokes with a second pad at a
Wangle to the direction of the first. At the first location, pads were
sprayed lightly with distilled water prior to wiping, while in the
remaining three sites (he pads were sprayed with isapropanol.
t
Wipe samples collected from treated synthetic carpet at one location, under three
sets of ventilation conditions, yielded surface loadings as follows:
No Ventilation - Mean 1.6 ^g/cm7, range 0.07 to 3.6 jig/cm2; CV 58%
Doors Open - Mean 0.67 j/g/cm2, range 0.25 to 1.0 /ig/cm2; CV 40%
Windows Open - Mean 0.71 /ig/cm\ range 0.13 to 1.8 fig/cm1,CV64%
Transferable residue on treated surfaces did not change substantially during the first
6 hr post-application, but decreased 30 to 40% within 24 hr post-application.
Residues decreased from a mean of 690 to 280 ng/cm: in 24 hr in rooms with
ventilation and from a mean of 1600 to 480 ng/cm2 in 24 hr in rooms with no
ventilation. Transferable residues on untreated surfaces increased during the 24
hours post application. Residues increased from a mean of 1.3 to 2.6 ng/cm2 in 24
hr in rooms with ventilation and from a mean of 1.4 to 4.7 ng/cm2 in 24 hr in rooms
with no ventilation.
EPA. 1993
The objective was to determine the quantity of malathion transferred
from carpet, painted sheetrock, and vinyl flooring onto skin or
gloves. Aqueous malathion formulation was sprayed onto 3x3 cm
patches of residential grade carpet, vinyl flooring, and painted
sheetrock. Samples equilibrated for lh. Either bare hand or hand
with cotton glove was placed on-treated surface. An inflatable cuff
was used tb apply even pressure for 15 sec. Malathion on bare hand
extracted with isopropanol rinse. Malathion on glove extracted with
acetonitrile.
Results:
% transferred (SD) at lh Ratiofhand/clovel
hand Suit
Carpet 152(0 64) 2 90(3.42) 0.94(0.53)
Vinyl Flooring 0.18(0.04) 0.10(0 03) 2.06(0.94)
Painted Sheetrock 0 03 (0 0) 0.02(0 0) 1.82(0.30)
Krieeer. 1996
In this study a solution of disodium octaborate tetrahydrate (DOT)
was applied to carpet at approximately 200 Mg/cm2 in an aqueous
solution. Transferable residues were sampled using a California
Dept. of Food and Agriculture (CDFA) roller method (roller over a
cotlon dosimeter with an area of 2,968 cm2). The dosimeter was
extracted with water.
Measurements of transferable residues made using the CDFA roller resulted in 0.15
± 0.01 mg/I. of boron in the water extract from carpet before treatment, 0.70 + 0.22
mg/L after treatment, and 0.22 * 0.05 after study participants exercised on the
carpet. [IF the roller dosimeter area is 2,96R cm2, the applied amount of boron was
200 /ig/cm\ and if the amount of water used to extract the dosimeter was 1 L, then
the approximate % transferable for boron was in the range of 0.1% as measured
with the CDFA method].
K-ll
-------
Method
Camann and Harding. 19%
This work compares the transfer efficiency of residues resulting
from broadcast application of pesticides onto several floor surfaces.
Included in the comparison were the Dow drag sled, the PUF roller,
and the California cloth roller, and a human hand press Samples
were collected 2 h afer application. The hand wipe was performed
with two 4"x4" dressing sponges, laced with lOmL isopropanol
Results
Mean Transfer %
Hand
Floonnn
Active Inured
Kloor Cone
Cloth roller
Drae .Sled
PUF roller
Press
(ng/cm2)
plush nylon
Chlorpyrifos
13.500
4.9
1.3
0 9
NT
carpel
plush nylon
Chtorpyrifos
19,H00
NT
0.40 dry
0.26 dry
NT
carpet
0.66 moisl
2 1 moisl
loop polyethy-
Chlorpyrifos
10,600
2.7
17
1.5
NT
ene carpel
plush carpel
ChlofpynTos
5.800
NT
005
002
0.02
(used)
Pipemnyl f!ut
5,760
NT
0.07
0.02
<0.005
Pyrethrin 1
555
NT
0.11
002
<0 01
sheet vinyl
Chlorpyrifos
8.000
NT
13
5.5
1.8
(new)
Piperonyl But
' 7,600
NT
12
4.7
2.2
Pyrethrin 1
1,200
NT
9
5 5
1.8
Experiments were also conducted to determine effect of # of passes, pass length,
pressure and speed on the transfer efficiency of PUF roller and drag sled method.
Results showed some variation in uptake although relationship was not linear.
E-12
-------
Method
Results
Camman, 1996
Compared the transfer efficiencies of dry pesticide residues to hands
moistened with human saliva, artificial saliva, or the surfactant
dioctyl sulfosuccinate (DSS)
-an 8 cm strip of palm (241 cm1 area) on the testers' hand was
wetted with 400 jiL of fluid, and then pressed onto the carpet (after
broadcast application of pesticide formulation) five times at 1
second and 1.0 psi each.
-gauze dressings sponges were wetted with 10 mL of isopropanol
for wiping, then placed in a container of 25 mL methanol. Wipe
samples were cold-shake extracted with diethyl ether and n-hexane
within 3 hours after collection.
-source: the pesticide mixture was 0.25% chlorpyrifos, 0.025%
pyrethrins, and 0.25% piperonyl butnxide in aqueous spray, applied
to a 7 fl. x 12 ft. piece of carpet at a rate of 1 gallon per 1600 ft2, 40
cm above test surface. Hand presses were made 5h, 1 day, and 2
days after application.
-The authors compared their transfer efficiencies to those of dry
hands, using values from a PUF roller and a drag sled obtained in a
prior experiment.
Mean Transfer lilficiencies (Calculated as the mass transferred / carpet loading)
Pyrethrin: DSS - 4.3%
Human saliva - 4.8%
Artificial saliva - 2.9%
Dry hand (puf roller estimate) - 0.01%
Dry hand (drag sled estimate) - 0.01%
Chlorpyrifos: DSS 1.3%
Human saliva - 1.1%
Artificial saliva - 0.73%
Dry hand (puf roller estimate) - 0.01%
Dry hand (drag sled estimate) - 0.01%
Piperonyl Dutoxide DSS - 2.8%
Human saliva - 2.8%
Artificial saliva - 1.5%
Dry hand (puf roller estimate) - 0.01%
Dry hand (drag sled estimate) - 0.01%
PUF roller used to estimate the transfer efficiency of a dry hand, about two orders
of magnitude lower than the transfer efficiency of a wet hand.
R-n
-------
Method
Results
Fortune. 1997
Performance of three transferable residue methods: the Dow drag
sled, the PUF roller, and the California roller was performed by
round-robin testing.
Testers used the methods according to modified SOPs.
f.
Sampling Precision
Chlorpyrifos Pyrelhrin I Piperonyt
Buloiide
PUF Roller 2K 3% 45 7% 39 7%
California Roller 27 1% 35 2% 29 7%
Dow Drag Sled 215% 2f> R% 25.8%
Transfer Efficiency
Chlorpyrifos Pyitthrin 1 Pipenmyl
Rutoxide
PUF Roller 14% 19% 1.8%
California Roller 4 2% 4 2% 6 6%
Dow Drag Sled 1.9% 2 .1% 2 3%
The authors conclude that reproducible and consistent data can be obtained for
transferable residues on carpet using any of the three methods described. The
subjective evaluations of the volunteers in the study consistently rank the California
roller lower than the Dow sled or the PUF roller (including ease of training,
cleanup, manipulations, time requirements, and assembly). Also, the high transfer
efficiency of the California roller is thought to be less representative of actual
human skin transfer efficiency.
E-14
-------
Method
Results
EPA, 1998 { Laboratory and field methods establish a dermal
transfer coelT...)
Experiments were conducted to determine the quantity of malathion
transferred from painted drywall, vinyl flooring, and nylon carpet to
human skin surrogates, cotton suit material and polyurethanc foam.
Malathion was applied to coupons of painted drywall, carpet, and
vinyl flooring by spray application of a technical grade malathion
solution. Coupons were conditioned, transfer experiments were
conducted at selected time intervals after application (0, 2,8,24, 48,
72 h).
Transferable residues were determined using the human hand and
different skin surrogates (cotton suit material), PUF, pig skin, and
cadaver skin. Transfer material was placed on coupon. An acrylic
plate was placed on top, 80 mm Hg applied, held for 15 s. Exposed
transfer materials were extracted with acetonitrile. Exposed hands
were rinsed with isopropanol.
Experiments were conducted to determine the dissipation rates of
malathion residues from typical residential surfaces. Data were also
generated on the effect of sampUng methods on the amount of
malathion recovered. Malathion as a chemical standard or as a
commercial product was spiked (25 uL aliquots) onto coupons
(usually 10 x 10 cm) of different material ( cotton suit material,
carpet, painted dry board, and vinyl flooring. Spiked coupons were
equilibrated under controlled temperature and humidity conditions.
Malathion remaining on the spike coupons at selected equilibration
times was measured using a) wipes with cotton suit material wetted
with acetonitrile - wipe extracted with acetonitrile; b)
extractabfe residue method - coupons shaken with water surfactant
solutions, aqueous solution extracted with methylene chloride.
Analysis also conducted for malaxon as the major breakdown
product of malathion.
% Transfer of Applied Malathion Measured Over 24 h After Application
Transfer Materia! Carpel Pitnkd Drywa!l Vinyl Floor
?h 24h Oh 74h 2h 24h
Human Hands 4 21% 015% 0.43% 0 077% 0 55% 0.35%
Pig Skin 2 1%% 0.054% 0 09% 0 015% 0 46% 0.025%
Catkin Suit Material 1.1% 0 4ft% 0 60% 0.006% 0.053% 0.023%
PI Jh 281% 0.55% 022% 001!% 0.39% 0.10%
Cadaver Skin 11% 0 22% 0 17% 0.014% 0.13% 0.20%
NOTb: Sample materials were spiked in a way that may not be representative of how pesticides are
applied to 01 transferred to surfaces in residential environments
No breakdown of malathion to malaxon observed. Wipe samples of carpet (26%),
vinyl flooring (89%), and painted drywall (78%) did not quantitatively recover
malathion. Recovery by cxtractable residue method, carpet (36%), painted drywall
(19%), and vinyl flooring (25%) were generally lower than by the wipe method.
All surfaces showed dissipation of malathion over a 72 h period - cotton suit
material showed the slowest dissipation, humidity showed little effect, dissipation
was highest at high temperatures. Different material showed different dissipation
rates using the wipe vs the extractable residue method. Rate constants and half-
lives were calculated for all conditions.
12 15
-------
Method
EPA. 1992 (
From literature review (Jurinski, 1984) surface wipe samples were
collected on gauze pads.
Results
Chlordane values of <0.1 to 39.8 ng/mi1
Transferable Dust
Edwards. In Preparation
A press sampler (EL sampler) was designed to collect surface dust
samples representative of what would be transferred to the human
hand during a single hand press. Housedust was allowed to settle on
precleaned glass slides. The slides were analyzed with an Adherent
Cell and Sorting (ACAS) interactive laser cytometer to determine
particle size distribution. The slides were next sampled with either
the EL sampler or a hand press. The EL sampler consists of a 10 x
15 cm extraction sheet loaded into a cassette. The sampler was
pressed onto the collection surface for a period of five seconds,
while all foiir legs of the sampler were in contact with the surface to
ensure equal pressure. The hand press was performed in a similar
mattner-a pressure as close to IS lb. was maintained for S seconds.
Both the EL sheet and hand were extracted with 2-propanol and
analyzed with GC/MS.
Cytometer analysis showed that both sampling methods removed 100% of the
particles between 60-250 In all size ranges, the amount of particles collected
was very similar. Pesticide recoveries were both found to be very high and very
similar, and the average collection efficiencies were also found to be very similar.
Particle Removal Efficiencies
Hand Press Test EL Sampler
0 - 2.5 um 68% 61%
2.5- 10 mn -0.8 % -64%
10 - 50 um 35% 56%
50 - 200 urn 100% 100%
Pesticide Collection Efficiency for
Hand Press Test EL Sampler
43 % 35%
29% 31%
43% 32%
21% 18%
Atrazine
Diazinon
Malathion
Chlorpyrifos
Lewis. 1994
Several types of measurements of surface pesticide loadings were
made in 9 homes with children. The HVS3 vacuum system was
used to collect carpet dust samples, a PUF roller was used to sample
carpet transferable residue, the investigator performed a hand press
(area of 97 cm2' on the carpet surface.
Mean results, all reported in Mg/m2 of carpet surface
HVS3
PUF Roller
Hand Press
Chlorpyrifos
1.3
0.11
0.03
Chlordane
4.5
0.54
0.56
Heptachlor
0.62
0.05
0.02
Dieldrin
0.12
003
-------
Method
Results
Nlshioka, 1996
Measurements were made for transferable turf residue after
herbicide application using a PUF roller method. Measurements of
residues in the homes resulting from track-in were made using the
MVS3 vacuum and carpet PUF roller methods.
Transferable Herbicide Residues (ppm):
Dicamha 2.4-D
Turf PUF roller 1800 1000
Carpet Dust (H VS3) 58 32
Carpet (PUF) 6 3
Percent transfers:
% turf transferables: 0.18 0.10
% transfer of turf
trans, to dust: 3.2 3.2
% transfer of turf
trans, to carpet: 0.35 0.32
The turf transferable levels were 0.1 - 0.2% of the turf application levels. This initial
transferable residue as measured by the PUF is much higher than the transferable or
total concentrations in the carpet, but there is a high correlation in their temporal
profiles. Both types of carpet residues decrease more slowly than the turf residue.
An increase in transferable residue was seen from 4-8 hours after application,
speculated to be due to the further drying of the pesticide. There were dramatic
decreases in residue after rainfalls, and decreases with time that are thought to be
due to enhanced absorption/binding to turf.
E-17
-------
Method
Results
Nlshloka. 1997
Transport of lawn-applied pesticides into the home via track-in on
shoes was measured. Lawns that had not previously hccn treated
with pesticides were divided into 20 ft x 20 ft plots. Herbicide
formulation applied: dicamba (1.7 mg/m1); 2,4-D (26.7 mg/m1);
dicamba isomer (0.16 mg/m1); granular chlorpyrifos (120 mg/m');
spray chlorpyrifos (140 mg/m1); chlorothalonil (970 mg/m2).
Carpeted track-in platforms were placed at one end of each lawn
plot, and 1.5 g of a sieved residential house dust was applied and
embedded (foil roller) in the carpet. Track-in was simulated when
participants walked 20 times through the right and left sides of a
given turf plot and stepped on the carpet. At the end of each
experiment, each participant had walked in each lane of each carpet
five times; residues from a total of 25 walks accumulated in each
lane of carpet. The PUF roller was used to collect residues on turf
(sampling rate of 40 cm/sec) and carpet (sampling rate of 17
cm/sec). Thfc HVS3 was used for a controlled dust collection of
areas that had been covered with tape during the experiment.
Relative Transfer of Pesticides from Turf
Transfer ppm (%)
Turf lo PUF Turf to Dust Turf to Carpel Surface
Dicamba spray 1800(0 18%) 58(3 2%) 6.2 (0 35%)
Dicamha isomer spray 2700(0 27%) 80(3 0%) 3 0(0 14%)
2.4-D spray 1000(0.10%) 32(3.2%) 3.2(0.32%)
Chlorothalonil spray 2100(0.21%) 42(2 0%) 6.1(0,28%)
Chlorpyrifos spray 76(0.008%) 1.3(1.6%) 0.3 (0.26%)
Chlofpynfus granular 45(0 005%) 8 0(18%) 0 2(0.44%)
Researchers also analyzed the temporal changes in pesticide levels in the turf and
carpet. They demonstrated that track-in on shoes is a reasonable mechanism by
which pesticides arc carried into the home. Data showed that the track-in of
residues occurred at 5-6 days after application, despite environmental conditions
(rain and voIatiliV^tion). They also showed that transferable residues were
detectable up to 14 days after application.
F.-I8
-------
Method
Results
Roberts. 19B9
Tesls were performed to determine if cotton gloves can be used to
measure the quantity of transferable pesticide residue in carpets
containing house dust with different pesticide concentrations
Reference carpet dust sections were prepared by first sieving house
dust to obtain the
-------
Method
Results
A
Dust/Soil - Adhesion
Durr. 1996
The purpose of this work was lo measure dermal absorption for
different skin soil loadings. Soils were loaded onto cadaver skin at
1 to 10 mg/cm1. Radiolabeled lindane and 2,4-D was added to the
soils. Amounts absorbed in the skin and through the skin were
measured.
v
Mean % absorptions were 0.45 to 2.35% for lindane and 0.18 to 1.59% for 2,4-D.
Percent of absorbed chemical will increase with decreasing soil load, providing that
monolayer or greater skin coverage is maintained. As loadings decrease below the
monolayer threshold, contact area and mass flux will decline leading to roughly
constant % absorption. Many activities are likely to result in loadings of 1 mg/cm2
or less, not providing complete monolayer coverage.
Kissel. 1996a
The relationship between activities and dermal loading over time
and body region were measured. Soil adhering to the subjects' skin
was measured by washing exposed body parts in water, filtering
these samples, and then weighing the desiccated samples. Pre-
activity levels were found in the same manner. The mass recovered
was converted to average skin loading using regression of the
surface area of the respective body parls. A ratio of pre- to post-
activity was also calculated. The data was compared to the current
default soil loading range (set at 0.2 - 1.0 mg/cm2 in 1992).
Post-activity hand, foot, arm, and leg data spanned the default range. In order of
lowest mean loading to highest, the activity groups were Tae Kwon Do, soccer,
groundskeepers, irrigation installers, rugby players, fanners, reed gatherers, and
kids playing in the mud. Only the loadings for the kids playing in the mud clearly
exceed the default range of 0.2 - 1.0 mg/cm1. Observed hand loadings varied over
five orders of magnitude (0.001 to 100 ng/cm2) and were dependent upon the type
of activity, dermal exposure lo soil appears to be episodic (daily periods of
exposure to higher loading levels arc likely to be less than 24 huurs for most
people).
EPA.. 1992
From literature review of soil skin loading estimates for children
-CDC (1984) - 1 g/day forO.75-1.5 years and 3.5-5 years; 10 g/day for 1.5-3.5
years
-EPA (1984)- 0.5 mg/cm2
-I.cpow (1975) - 0.5 mg/cm1
Roels (1980) 159 mg/hand
-Que-Hee (1985) - 0.2 mg/cm2
Driver (1989) - 1.298 mg/cm2 for particles < 150 ^m; 0 946 mg/cm1 for particles
< 250 fjm\ 0 582.1 mg/cm1 for unsieved soils (1989)
-Sedman (1989) - 1 g/day for 1-5 years
E-20
-------
Method
Kissel. 1996b
The effect of particle size and moisture content of soils on the
adherence of soils to skin was measured. Five soils were ublained
locally, and analyzed by hydrometer (settling velocity) to determine
composition (sand, silt, clay). Organic carbon contents were
determined by combustion.
The hand press protocol involved placing hand palm-down in a pan
of soil, gently agitating for 30 seconds, and (hen washing the hand
(2% detergent solution) into a sample jar. Wash water was filtered
through 37 nim glass Tiber filters with a nominal pore size of 0.5
^m. Vacuum was applied by aspirator or pump. Filters were then
oven dried overnight at 100°C, then cooled in a desiccator, and
weighed.
Results
With dry soil conditions (<2% moisture), adherence varied inversely with grain
size. In wet soils (12-18% moisture), adherence generally varied directly with
particle size. Effect of moisture on adherence of fine particles is inconsistent across
soils, which may reflect differences in the surface characteristics of the various
soils. Effects on larger particles arc less variable. For whole soils (unfractionated),
the adherence at moisture contents above 20% differed significantly from adherence
at less than 10% moisture and adherence at 10-20 % moisture. Results from post-
adherence sieving show a preferential selection of smaller sized particles under dry
conditions. For each soil, under dry conditions, the relative proportion of sub-65
Mm particles increases about 4-fold, while very little of the largest class adheres to
skin. The sub-65 tim grains represent the largest single fraction of the sieved
washed soil. A significant decline in the relative adherence of this size group is
apparent under wet conditions. Increasing adherence of unsieved soils with
increasing soil moisture appears to occur primarily as a result of the efTect of
moisture on adherence of larger size fractions.
Mean Adherence (mg/cm1)
Soil
Moisture
<0.1 to 9%
10 to 19%
21 to 27%
211
0.33
3.09
5.88
CP
0.22
2.98
14.8
85
0.25
1.26
5.99
228
0.22
0.45
1.64
72
0.54
0.39
2.10
Van Hrnimfen, 1995
From a review of dermal exposure research literature was a report
from Paustcribach, et al , 1992 estimating soil adhesion to skin.
A value of 0.5 mg/cm2 adherence of soil was proposed as a reasonable estimate
from contact with soils.
H 21
-------
Method
Results
WA-023 (Rodes/Lewlsl. 1998
A dust deposition chamber that uniformly applies dust loadings
typical of real indoor horizontal surfaces (30 to 50 ug/cm2) was
developed.. Dermal mass transfer rates of dust particles of known
diameters ^ere measured from smooth stainless steel surfaces,
carpet, and vinyl flooring. Tests were performed with dry and moist
hands, witKsynthetic saliva, and for direct and smudged contacts.
Actual contact areas are typically 30-40% of the entire hand projected area.
A portion of the particles transferred from a contact surface to the skin are often
transferred back to the contact surface in successive contacts, so that the mass
transfer rate afler 50 contact events may be only 20-30% of the rate for the first
transfer. Transfer rates of dust particles (0-80 /iin) from smooth stainless steel
surfaces to dry skin range are 60 to 80%. Particle mass transfer rates from vinyl
flooring are 20-40% less than from smooth stainless steel surfaces for
0-80 A/m bulk dust. Preliminary dermal mass transfer rates for 0-80 /zm particles
from medium pile carpeting show dry skin transfer rates are typically <10% of those
from smooth contact surfaces and that damp skin transfer rates are 2-3 times higher
than dry skin rates. The presence of a "wet" synthetic saliva layer on the skin does
not necessarily result in a greater mass transfer rate from stainless steel surfaces.
Damp skin particle mass transfer rates from smooth surfaces are typically 20-40%
less than dry skin rates for larger particles (40-80 pm), but somewhat higher than
dry skin for 0-10 nm fine particles. Fine particles (0-10 ^m) appear to transfer more
readily from an uncharged contact surface to the skin than large particles or bulk
dust.
Driver. 19$9
Soil conditions (soil type, particle size, and organic content)
affecting adherence to skin were assessed.
Three soil particles sizes tested were <150 ^m, <250 ^m, and
unsieved soil.
Five different Virginia soils types were tested.
-A known weight of soil was placed into a clean, tared plastic
container.
-Adult han&s were placed into the soil for a 30 second contact
period with constant agitation in the soil.
-The weight of soil adhering to the skin was measured by weighing
the plastic container after contact.
-Hand surface area was estimated empirically from body weight and
height.
The most important factor affecting adherence variability was particle size.
Soil Adherence bv Particle Size (me/cm1)
Unsieved soil: 0.17 to 0.90; mean = 0.58
<250/im: 0.80 to 1.23; mean - 0.95
<150 /im: was 0.76 to 1.85; mean =1.40
Soil Adherence bv Oreanic Content (me/cm1)
19% Organic: mean = 0.36 for unsieved soil and 0.79 for <150 /jm.
1% Organic: mean = 0.60 mg/cm2 for unsieved soil and 0.97 for <150 j/m.
Note: included review of related studies with values for soil adherence ranging
from 0.2 mg/cm2 to 0.9 (mg/cm1).
E-22
-------
Method
Results
EPA. 1992
From literature review Driver et al. (1989) and Sedmen (1989)
reviewed field studies of soil adherence to skin:
Lepow et al. (1975) use tape stripping
Roels et al. (1980) used nitric acid rinse (Tor lead)
Hrager (1979)
1
Lepow: 0.5 mg/cmJ
Rods: 0.9 mg/cm'
(larger: 1.45 mg/cm2 for potting soil and 2.77 mg/cm1 for kaolin dust
a
Whole body dosimeters
EPA. 19984
Work was conducted to generate a dermal transfer coefficient for
the crawling activity. This effort is based on the hypotheses that a
dermal transfer coefficient can be used to extrapolate adult human
test subject data to infants or children. It also assumes that accurate
transfer coefficients can be developed using concurrently generated
whole-body dosimetry, transferable residue data, and biomechanics
data. This study used video analysis to establish the relationship
between child contact activities and the uptake of dislodgeable
surface residues. A broadcast application of a 0 5% solution of
chlorpyrifos was made to carpet'. Four hours after application, an
adult test subject, wearing a whole-body dosimeter (cotton body
suit, gloves^ and socks), crawled on the treated carpet for
approximately 2.5 minutes. After this activity, the dosimeter was
removed, segmented to represent various body parts, and analyzed
for pesticide residue uptake. Coupon samples on the carpet were
used to measure chlorpyrifos deposition. The experiment was
repeated 3x with the same adult subject. Biomechanical data were
collected for # of contacts per body parts, duration of contact,
average surface area making contact, average body pari contact
pressures; and contact surface areas for each part.
1. Chlorpyrifos deposition was 13.6 to 11.9 ug/cm2 for carpet. Extractable
residues as measured by shaking with water/surfactant were 42, 58, and 44% of
deposition rates.
2. Total exposure measured (hands, feet, shins, and knees) were 1,326 to 1665 ug.
The mean exposure of the three replicates was not significantly different. In all
cases, the left side had higher levels of chlorpyrifos. The transfer coefficient was
5854 cm2/h.
3. % transferred residue was 0.21% for left hand, 0.19% for right hand, 0.61% for
left knee, and 0.45% for right knee.
4. A relationship between biomechanic activity and exposure (0.94 Spearman
coefficient between pressure and exposure) was shown.
F-23
-------
Method
Results
EPA. 1993
The objective was (o determine the transfer of malathion from
treated surfaces to a subject performing post-deposition activities. 1
h after spraying, an adult subject in full cotton body suit entered the
room and began a series of 16 crawling and playing activities. Each
activity was performed twice over a 32 minute period. AUcr
activities, the subject left the room, suit was removed, segmented by
body part; separate body parts were extracted and analyzed
individually. The study was conducted 3x.
Rear, feet, and hands showed the highest malathion levels. The overall mean
amount of malathion found on the dosimeter garments across the three tests was
1875 Atg. Amounts found on different body area segments ranged from 1.7 ^g (left
elbow) to 788 (pants, rear). Levels in second and third experiment were higher
than the first. The surface was still wet during exposure, the body suit may have
adsorbed higher concentrations.
Krleeer. 1996
In this study a solution of disodium octaborate tetryhydrate (DOT)
was applied to carpet at approximately 200 ^ig/cm2 in an aqueous
solution. ,Five volunteers wore whole-body dosimeter garments
and performed a Jazzercise® routine to measure potential dermal
transfer ami 17 others wore only bathing suits. Urinary boron
excretion was measured before and after the exposure. Each
volunteer collected urine specimens over four-hour intervals starting
the day before the exposure exercise event continuing through one
day after their exercise exposure event.
Measurements of transfer of boron to the whole body dosimeters during the exercise
routine were:
Socks: mean 18 mg range 1 to 56 mg
Gloves: mean 6 mg range 0-19 mg
Union suits: mean 19 mg range 0 - 82 mg
The large variability in whole body dosimeter results may reflect the distribution of
DOT on different areas of the carpet and variation in the residual moisture in the
carpet and carpet pad.
l;or the 17 exposed volunteers, mean urine boron concentrations were:
Day prior: 1.17 ± 0.63 mg/g of creatinine
Day of event: 1.33 ± 0.68 mg/g of creatinine
Day after: 1.31 ± 0.66 mg/g of creatinine
For the 5 volunteers wearing the body dosimeters, and presumably unexposed,
inean urine boron concentrations were:
Day prior: 1.26 ± 0.42 mg/g of creatinine
Day of event: 1.12* 0.30 mg/g of creatinine
Day after 1.26 ± 0.41 mg/g of creatinine
In summary, it was concluded that there was no measurable dermal absorption or
significant uptake of DOT.
F,-24
-------
Method
Results
Ross, 1990
Five volunteers wore dosimeter clothing during an exercise rouline
In measure dermal transfer in rooms treated with home foggers
containing chlorpyrifos and allethrin. Volunteers went through a 20
min orchestrated Jazzercise® routine on specified floor locations
At specific time intervals, they changed dosimeter clothing and went
through the same routine in a similarly treated room. Two
experiments' were performed at each of three Kmc intervals (0, 6,
and 12.5 hr) after fogger release and after a two hour unventilated
and 30 minute ventilated reentry waiting period. Four types of
clothing (cotton socks, cotton gloves, cotton shirts, and cotton
tights) were worn as dosimeters of dermal transfer.
Accumulated residues on dosimeter clothing were measured for three times after
reentry into the treated rooms; 0, 6, and 12 - 13 hr.
Mean results for chlorpyrifos combining results for all five volunteers:
l ights: 11'JU U> 12 JO Kg al 0 hr 853 k> 857 il 6 hr 298 to 497 II 12 - 13 hr
Shuts 946 to 1043 fig at 0 hr 557 lo 664 /jg at 6 hr 274 to 319 /ig at 12 - 13 hr
Socks: 7.54 lo 1020/jg at 0 hr 561 lo 706/jr at 6 hr 268 to 381 /jg at 12 - 13 hr
Gloves: 459 lo 570 al 0 hr 320 to 372 Kg al 6 hr 117 to 163 at 12 -13 hr
CV values ranged from approximately 22% to 82% across the five individuals for
one test. Next, the pesticide concentration on the clothing (j/g/cmJ) was divided by
the concentration measured on ihc floor to determine the percentage of applied
pesticide transferred. Results were:
Tights: 6.6%al0hr 7.5% at 6 hr 4.0% at 12 - 13 hr
Shirts: 5.6%atOhr 6.3% at 6 hr 3.1% al 12 - 13 hr
Socks: 32% at 0 hr 33% at 6 hr 20% at 12 - 13 hr
Gloves: 14%at0hr 14%at6hr 12% at 12-13 hr
Hand wipes
Geno. 1996
At a time of 15 - 30 sec after hand contact with a surface fortified
with pesticides, hands wiped with cellulose dressing sponge wetted
with 2-propanol.
Handwipe efficiency of 104 ±11% for chlorpyrifos and 92 ± 28% for pyrethrin 1.
Removal efficiencies for 29 other pesticides show most removal efficiencies are
>70%.
Bradman, 1997
Handwipe samples were collected from 11 rural children. All hand
surfaces were wiped 2x with gauze pads wetted with propanol.
Diazinon was detected (220 to 52 ng) on the hands of three of toddlers with the
highest housdust loadings; chlorpyrifos was detected (100 to 20 ng) on the hands of
the two toddlers that has the highest house dust loadings; all three resided in
farmworker homes; no other compounds were detected.
E-25
-------
Method ;
EPA. 1993
The objective was to determine the precision, accuracy, recovery
efficiency, and overall method quantitation limit for malathion on
hand and forearm skin.l in2 of each hand or forearm was spiked
with aqueous malathion suspension, equilibrated fnr 15 min liach
hand was placed in a separate polyethylene bag with 250 ml. of
isopropanol. Dag was sealed tightly and hand shaken in bag for 30
s. Forearm swabbed with cotton pieces wetted with isnpropanol.
Results
Both methods gave quantitative recovery ranging from 97 to 120% with RSD of 1.2
lo 26 %. The LOQ was lug/in2.
Lewis. 1994
Several types of measurements of surface pesticide loadings were
made in homes with children. Hand rinses were performed for 4
children using 2-propanol. Results from the hand rinses (assumed
total hand surface area of 300 cm1) were compared against results
for three other methods including the HVS3 vacuum system used to
collect carpet dust samples, a PUF roller used to sample carpet
dislodgeable residue, and an investigator hand press (area nf 97 cm3)
on the carpet surface.
Mean results, all reported in ng/cm*
Child
PUF
Investigator
Hands
HVS3
Roller
Hand Press
Chlorpyrifos (Home 1)
0 21
0.44
0.64
0.01
Dieldrin (Home 1)
0.01
0.04
0.05
ND '
Chlordane (Home 2)
1.2
1.6
1.5
0.40
Heptachlor (Home 2)
0.32
0.42
0.43
0.10
Heptachlor (Home 3)
0.03
0.03
0.43
0.04
PCP (Home 2)
0.06
0.02
0.04
0.04
PCP(Homc 4)
0.09
0.02
0.11
ND
E-26
-------
Method
Results
YukanaWee. 1997
Estimates of dermal (hand palm) loadings were derived primarily
from applicator/occupational literature reports, of hand skin and
glove measurements. Assumptions used in the derivation, many
derived from the literature, included:
-100% of the pesticide measured from hand rinse or gloved hand
studies was deposited on the palmer hand surfaces.
-Deposition was evenly distributed across fingers, thumbs, and
palms of both hands.
-Total surface area ranged from 73 to 1170 cm2. A rounded value of
500 cm1 is the area of one hand and 250 cm1 is the palmer surface
area of one hand.
-Deposition rates (mg/h) may be converted to mass by multiplying
by the collection duration since literature reports show is no
correlation between the length of a collection period and
establishment of a depositional steady state.
-Gloves used to measure deposition may retain 5 times mor
pesticide than skin. Hand rinses underestimate deposition. A factor
of two was used to adjust glove data downward and a factor of two
was used to adjust hand rinse data upward.
-Using these assumptions, the palmer mass was calculated from:
Palmer mass (fit/250 cm1)" [Exposure (j-ic/handsftri x coHecbcm duration fmin) x Adjustment (2
or 0-3)1
2 hinds ft 60 min/h
From literature reports of pesticide residues recovered from worker and applicator
hands, the above equation was used to calculate palmar mass ranges. Ten of the 34
calculated palmar mass ranges are reported here, spanning the range of reported
values:
1 to 4 /ig/250 cm' 750 to 31,000 ;ig/250 cm2
6 to 24 /ig/250cmJ 1500 to 5,100 jig/250 cm1
27 to 172 A/g/250 cm2 2000 to 5,000 >jg/250 em2
310 to 1,085 /ig/250cm2 3,900 to 14,000/ig/250 cm2
800 to 2,000 A/g/250 cm! 4,900 to 31,000 /ig/250 cm2
F.-27
-------
Method
Results
Non-Dietary Ingestion
Hand or Object to Mouth
Gurunathan. 1998
Measurement of toy and surface chlorpyrifos residues after
application. Use of video activity data to estimate hand-to-mouth
activity. Assuming 100% transfer for each touch and 365
contacts/hr, estimated oral dose calculated.
Estimated that an oral dose of 126 //g/Vg/day would be experienced by a child one
week after chlorpyrifos was applied.
Soil/dust ingestion
KisseL 1998
Hand-to-mouth transfer of soil was measured for adult subjects.
The soil usetl was the sub 2mm fraction of a locally obtained,
natural loamy sand, soil was autoclaved and stored at room
temperature under foil; moisture content ranged from O R to 1.6%.
The experimental protocol consisted of 9 steps: 1) washing and
drying the subject's hands; 2) loading one hand by pressing into a
shallow pan (palm down, fingers spread); 3) mouthing three fingers
above the first knuckle; 4) rinsing the mouth 3 times; 5) sucking
the thumb; 6) rinsing the mouth 3 times; 7) licking the palm (3x);
8) rinsing the mouth 3 times; 9) washing the remainder of the soil
from the hand. Initial soil loading on the hand was determined as
mass lost from the pan. Wash water was filtered through 47-mm
glass fiber filters with a nominal pore size of 0.5/jm. The pre-
weighed filters were oven dried overnight, cooled in a desiccator,
and weighed Surface area was calculated using correlations with
height and weight
Mean mass transferred from hand tn mouth was approximately 10 mg per event
(thumb sucking 7.4%, finger mouthing 11.6%, palm licking 16.0%) with a range of
5.9 to 20.4 mg.. The mean percentage of total soil on the hand recovered from
mouth was approximately 15% with a range of 6.2 to 23.7%. Soil mass transferred
to mouth tends to vary directly with hand loading.
Stanek. 1997
Soil ingestion among adults was measured. Test subjects were fed
soil tablets, and their total fecal output was collected for seven days.
Estimates of the soil ingested were constructed using the trace
element totals from the capsules.
Estimates indicate that the average adult ingests 10 mg soil/day, with an upper 95%
value of 331 mg soil/day
E-28
-------
Method
Results
Calabresel 1996
In this study, the authors addressed the large intertracer
inconsistencies present in soil ingestion estimates. They theorized
that the cause of the variability is differences in soil concentration
between elements by particle size. The authors re-analyzed the soil
ingested by children after it had been sieved to the smaller particle
size of <250 ^m. These new concentrations were then used to
estimate soil ingestion, and Ihe resulting estimates were compares
with the original ones (<2mm).
Soil samples were passed through a 250 f4m sieve. The
concentrations were estimated using inductively coupled plasma
atomic emission spectroscopy (ICP-AES) for Al, Ti, and Si, and
inductively coupled plasma mass spectroscopy (ICP-MS) for Ce,
Nd, La, Y, and Zr.
The data for this experiment came from another study (Calabrese ct al 1996), and
included the total amount of trace elements from food and fecal samples for 62
children, as well as concentrations of trace elements estimated from soil samples
collected in each child's yard.
Distributions of soil ingestion estimates were reported for the children residing in
Anaconda, Montana (n=62). Values presented included the minimum, 25%ile,
median, 75%ilc, 90%ile, 95%ile, and maximum. Only the mean and std are
included in this summary.
Tracer Specific Soil Ingestion (run/day)
Al: Mean = 1, Std = 90
Si: Mean = -19, Std = 64
Ti: Mean = -590, Std = 2606
Y: Mean = 38. Std = 116
Zr: Mean = -17, Std = 97
Calabresc. 1997a
This study was designed to assess soil ingestion in children who
were thought to display soil pica-like behavior based on
retrospective parental observations.
Food and fecal samples were collected from test subjects (described
by their parents as displaying frequent soil pica behavior), as well as
outdoor soil samples and indoor dust samples. The samples were
assessed for three tracer elements: AL, Si, and Ti. Mass-balance
estimates were calculated by subtracting the food amount from the
trace element amount in feces, and then dividing this difference by
the concentration of the trace element in either soil or dust.
Daily Median Soil and Dust Ineestion Rates fe/dav)
Soil Ingestion Dust Ineestion
Mean 0 135 0.271
Median 0.011 0 017
Std 0.278 0.758
One of the 12 children showed soil pica behavior. The remaining children had soil
ingestion estimates that were generally low, with median values under 40 mg/d for
each tracer.
F.-29
-------
r.'.
Method
Results
El* A. 1992
From EPA literature review, estimates of soil and dust ingestion for
children.
—KI'A(I984)- 100 mg/day
-CDC (1989) - 10,1)00 nig/day for 1.5-3 5 year olds; 1,000 mg/day for 0.75-1.5
years and 3.5-5 years
-Sedman (1989) - 590 mg/day
-Hawley (1985) - 165 mg/day
-LaGoy (1987) - 250 mg/day for 0-1 years and 6-11 years; 500 mg/day for 1-6
years
Calabrese (1987) 200 mg/day average for children under 7 years
-Clausing (1987) - 56 mg/day
- Binder (1986) - 121-184 mg/day
cllabrese. 1997b
In this report the authors examine potential acute exposures of
children exhibiting pica behavior. The authors argue that instead of
being a rare behavior confined to a small fraction of the population,
pica behavior may be normal but relatively infrequent for most
children in the general population.
Ingestion dose values were calculated for 13 chemicals (at EPA soil
screening levels) assuming pica soil ingestion rates of 5, 25, and 50
g/day. These estimated doses were then compared to reported
values for human toxicity and lethality.
i
The authors estimate that 62% of all children will ingest >1 g of soil,, 42% of
children will ingest >5 g, and 33% of children will ingest >10 g of soil on 1 - 2
days/year.
Potential doses from pica behavior of soils with contaminants present at the EPA
screening values were greater than reported lethal doses for cyanide, fluoride,
phenol, and vanadium. Potential doses greater than reported human toxic doses
were found for barium, cadmium, copper, lead, and nickel. Soil pica ingestion
doses lower than reported toxic doses were found for antimony, arsenic, and
naphthalene. Nonlethal toxic dose data were not found for pentachlorophenol.
EPA derived soil screening values are based on chronic ingestion of 200 mg/day for
soil, considered to be the upper 95"' percentile for soil ingestion. However,
contaminant levels that are safe for chronic exposure at this soil ingestion rate may
result in acute toxicity for pica behavior if 5 to 50 g of soil is consumed at one time.
E-30
-------
APPENDIX F: Chlorpyrifos Exposure Assessment
IMPORTANT PATHWAYS OF DERMAL ADSORPTION /NONDIETARY INGESTION FOR YOUNG CHILDREN IN THE
HOME - Chlorpyrifos estimated from available literature data.
Used is a first pass to determine which routes and scenarios would give the highest exposure
Form
Contact Surface
Contact
Type
Route
Assumptions
Estimated
Exposure
(ug/day)
Estimated
internal Dose
(ug/day)
CHRONIC DERMAL EXPOSURE
Dust
Carpet
5.0 ug/m2 -
extractable surface
concentration (HIPES,
Fenske);
5% transferable
(Rodes)
Hand
Ingestion
hand to surface contact - 0.035 m2
(EPA), 10 hand-to mouth per h
(Freeman), 4 hour ('/i EPA),50 %
available once absorbed
0.35
0.18
Body
Adsorption
**macroactivity approach - 50%
available for transfer, transfer
coefficient 0.87 m2/h, 4 h, 1%
dermal adsorption for pesticide not
bound to particles
8.7
0.087
Hard Surface
1.0 ug/m2 -
extractable surface
concentration (HIPES,
extrapolate Nishioka)
50% transferable
(Rodes, Edwards)
Hand
Ingestion
hand to surface contact - 0.035 m2,
10 hand-to mouth per h, 4 hour,
50% available once absorbed
0.7
0.35
Body
Adsorption
**macroactivity approach - 50%
available for transfer, transfer
coefficient 8.7 m2/h, 4 h, 1 % dermal
adsorption for pesticide not bound
to particles
17.4
0.17
F-l
-------
Form
Contact Surface
Contact
Type
Route
Assumptions
Estimated
Exposure
(ug/day)
Estimated
Internal Dose
(ug/day)
Dust
2.0 ug/g (HIPES)
Food or
hand-to-
moulh
Ingestion
50 mg dust ingested per day
(Calahrese), 50 % available once
ingested
0.1
0.05
-------
Form
Contact Surface
Contact
Type
Route
Assumptions
Estimated
Exposure
(ug/day)
Estimated
Internal Dose
(ug/day)
ACUTE DERMAL EXPOSURE
Residue
Carpet
75 mg/m2-
extractable surface
Hand
Ingestion
hand to surface contact - 0.035 m2,
10 hand-to mouth per h, 4 hour,
50% available once ingested
210
105
concentration (HfPES,
SwRJ)
0.2%
transfcrablc(SwRI)
microactivity approach - contact
area - 75 m2/hour, 4hour/day, 1%
dermal adsorption
45,000
450
Body
Adsorption
** macroactivity approach
50% available for transfer, transfer
coefficient 0.87 m2/h, 4 h, 1%
dermal adsorption,
130,500
1305
Hard Surface
75 mg/m2- extractable
surface concentration,
Hand
Ingestion
hand to surface contact - 0.035 m2,
10 hand-to mouth per h, 4 hour,
50% available once ingested
2100
1050
2% transferable
(SwRJ)
Body
Adsorption
** macroactivity approach
50% available for transfer, transfer
coefficient 8.7 m2/h, 4 h, 1% dermal
adsorption,
1,305,000
13,500
F-3
-------
Form
Contact Surface
Contact
Type
Route
Assumptions
Estimated
Exposure
(ug/day)
Estimated
Internal Dose
(ug/day)
HardToys
75 mg/m2 -extractable
surface concentration.
Hand
Ingestion
hand to surface contact - 0.035 m2,
10 contacis/h; 4 h/day, 50%
available once ingested
2100
1050
(Gurunathan),
2% transferable,
assumed as above
Hand
Adsorption
hand to surface contact - 0.035 m2,
10 contacts/h; 4 h/day, 1% dermal
adsorption,
42
21
direct
mouth
Ingestion
mouth to surface contact - -
0.0015m2,10 contacts/h; 4 h/day,
50% dislodgeablc, 50% available
once ingested
2250
1125
F-4
-------
Form
Contact Surface
Contact
Type
Route
Assumptions
Estimated
Exposure
(ug/day)
Estimated
Internal Dose
(ug/day)
OTHER EXPOSURE ROUTES
Food
Ingestion
3 ng/g; 500 g eaten; 50% available
1.5
0.75
Water
Ingestion
1 ng/g; 0.5 L; 100% available once
ingested
0.5
0.5
Air
Inhalation
application day - 15ugm3,; 10 m3
inhaled; 100% available
150
150
Inhalation
14 days post application - 0.5
ug/m3; 10 m3 inhaled
5
5
Inhalation
0.31 ug/m3 (NOPES) - 10m3 inhale
3.1
3.1
Inhalation
1.6 ug/m3 (HIPES) - 14 days post
application
16
16
micro activity approach
Exposure (ug/day) = extractable surface concentration (mg/m2) x fraction transferred x area of surface contact (m2/h) x h/day in
activity
macroactivlty approach (method used in OPP SOPs)
Exposure (ug/day) extractable surface concentration (mg/m2) x percent available to transfer x transfer coefficient* (m2/h) x h/day in
activity
* transfer coefficient takes into account both fraction transferred and the contact area
F-5
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06/01/99 TUE 13:14 FAX 9195410715 PROG OPS STAFF NERL RTP @002
NERL-RTP—0-631 TECHNICAL REPORT DAT
h
1. REPORT NO.
600/R-99/039
2.
3.RECIPIENT'S ACCESSION NO.
4. TITLE AND SUBTITLE
termal and Non-Dietary Exposure Workshop
5.REPORT DATE
G.PERFORMING ORGANIZATION CODE
7. AUTHOR(5)
Elaine Cohen-Hubal, Kent Thomas, Jim Quackenboss, Ed Pur taw
and Linda Sheldon
).
9 PERFORMING ORGANIZATION NAME AND ADDRESS
National Exposure Research Laboratory
I [uman Exposure Research and Atmospheric Scierces Division
U.S. Environmental Protection Agency
F^search Triangle Park, NC 27711
10.PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
1L SPONSORING AGENCY NAME AND ADDRESS
National Exposure Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
I.esearch Triangle Park, NC 27711
13.TYPE OF REPORT AND PERIOD COVERED
14. SPONSORING AGENCY CODE
15. SUPPLEMENTARY NOTES
15. ABSTRACT
A dermal and non-dietary ingestion exposure workshop was sponsored by U.S. EPA's National Exposure Research
Laboratory (NERL) on September 17,1998. The purpose of this workshop was co gather information on the state-of-the-art
in measuring and assessing children's exposures to pesticides via dermal contact with contaminated surfaces and objects as
v rell as by non-dietary ingestion. Although the NERL human exposure research program covers exposure from source to
dose, this workshop focused on characterizing concentrations of pesticides in the exposure media (on surface/object) and on
quantifying the transfer of contaminants to the skin surface or mouth. The following report discusses the focus of the
dermal exposure workshop, summarizes the workshop discussions and identifies research priorities based on a review of
the literature, workshop discussions, and expert input
17. KEY WORDS AND DOCUMENT ANALYSIS
a DESCRIPTORS
b. IDENTIFIERS/ OPEN ENDED
TERMS
c.COSATI
1 i DISTRIBUTION STATEMENT
FULEASE TO PUBLIC
19. SECURITY CLASS (This Report)
UNCLASSIFIED
21. NO. OF PAGES
20. SECURITY CLASS (This Page)
UNCLASSIFIED
22. PRICE
22::o-i
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