xvEPA
United States
Environmental Protection
Agency
Draft Protocol for Measuring
Children's Non-Occupational
Exposure to Pesticides by all
Relevant Pathways
-------
EPA/600/R-03/026
September 2001
Draft Protocol for Measuring Children's
Non-Occupational Exposure to Pesticides by
all Relevant Pathways
by
Maurice R. Berry, Elaine A. Cohen Hubal, Roy C. Fortmann, Lisa J.Melnyk,
Linda S. Sheldon, Daniel M. Stout II, Nicolle S. Tulve, and Donald A. Whitaker
Human Exposure and Atmospheric Sciences Division
National Exposure Research Laboratory
Research Triangle Park, NC 27711
and
Microbiological and Chemical Exposure Assessment Research Division
National Exposure Research Laboratory
Cincinnati, OH 45268
Contract nos. 68-D-99-011 and 68-D-99-012
Ellen Streib, Project Officer
Human Exposure and Atmospheric Sciences Division
National Exposure Research Laboratory
Research Triangle Park, NC 27711
National Exposure Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
/T"V Recycled/Recyclable
Printed with vegetable-based ink on
paper that contains a minimum of
50% post-consumer fiber content
processed chlorine free.
-------
Notice
The U.S. Environmental Protection Agency through its Office of Research and
Development funded and managed the research described here under Contract Number 68-D-99-
011 to Battelle and Contract number 68-D-99-012 to RTI International. It has been subjected to
the Agency's peer and administrative review and has been approved for publication as an EPA
document.
Mention of trade names or commercial products does not constitute endorsement or
recommendation for use.
11
-------
Abstract
In support of the Food Quality Protection Act (FQPA) of 1996, research is being
conducted by the U.S. EPA National Exposure Research Laboratory to develop methods, data,
and models for evaluating children's aggregate exposure to pesticides by all relevant pathways.
The FQPA requires the EPA to use exposure assessments in the pesticide tolerance setting
process. The exposure assessments must consider the aggregate exposures of infants and
children from all sources (food, water, soil, dust, and air) and routes (inhalation, dermal
exposure, indirect ingestion, and dietary ingestion). FQPA requires that risk assessments must be
based on exposure data that are of high quality and high quantity or exposure models using
factors that are based on existing, reliable data. Currently, the data on children's exposures and
exposure factors are limited and generally not adequate to assess residential exposures to
consumer products and environmental contaminants. Several general areas of research are
needed to improve the quality and quantity of data available for exposure assessments for
children. Appropriate age and developmental benchmarks for categorizing children in exposure
assessments must be identified. The activity pattern data for children (especially very young
children) required to assess exposure by all routes need to be developed. Methods for measuring
children's exposures need to be developed and improved. Finally, field studies are needed to
develop distributions of exposure and associated exposure factors.
The goal of this document is to provide guidance for generating data that can be used to
improve exposure assessments for young children, as required by FQPA. Currently, standard
protocols for conducting exposure field studies that provide data for measurement-based
exposure assessments do not exist. Likewise, protocols for developing exposure factor data to be
used for modeling assessments are not available. Although research on children's exposure to
pesticides and other toxic chemicals is being performed within EPA, academia, industry, and
other research organizations, protocols that have been developed by individual researchers for
specific studies do not always collect all of the data required for reliable exposure assessments,
and the data collected cannot always be interpreted.
The draft protocol provides approaches and methods that can be used for conducting field
studies to collect exposure measurement data and to develop exposure factors. The protocol first
provides a framework for conducting measurement studies for aggregate exposure assessments
then describes the algorithms developed to assess exposure by each route. The algorithms are
used to determine a priori what data must be collected in field studies to quantify exposure; the
protocol provides explicit data requirements for each route of exposure. The approaches for
estimating exposure by each route are described and include discussions of the data requirements,
general considerations related to data collection, measurement methods, collection of activity
pattern information, and exposure factors. The use of activity diaries and questionnaires is
discussed for each route of exposure. The use of biomonitoring data is also discussed.
This report covers the period from January 1999 to September 2001.
in
-------
Page Intentionally Blank
-------
Contents
Abstract iii
Figures vii
Tables viii
Acknowledgment ix
1.0 INTRODUCTION 1
1.1 Background 1
1.2 Purpose 2
1.3 Scope 3
1.4 Format of the Document 4
2.0 BASIC CONCEPTS OF AGGREGATE EXPOSURE 5
2.1 Definitions 5
2.2 Measurement Methods Versus Approaches 5
2.3 Exposure Assessment 8
2.4 Framework for Exposure Assessment 9
3.0 EXPOSURE ALGORITHMS AND DATA REQUIREMENTS 15
3.1 Exposure Algorithms 15
3.2 Inhalation Route 16
3.3 Dermal Route 19
3.3.1 Macroactivity Approach 20
3.3.2 Microactivity Approach 21
3.4 Ingestion Route 23
3.4.1 Dietary Ingestion 25
3.4.2 Indirect Ingestion 26
4.0 EXPOSURE SCENARIO 31
5.0 APPROACH FOR ESTIMATING INHALATION EXPOSURE 35
5.1 Introduction 35
5.2 Summary of Data Requirements 35
5.3 General Considerations 35
5.4 Monitoring and Sampling Methods 37
5.5 Exposure Factor/Activity Pattern Information 40
5.6 Estimation of Inhalation Rates 42
6.0 MACROACTIVITY APPROACH FOR ESTIMATING DERMAL EXPOSURE .... 46
6.1 Introduction 46
-------
6.2 Summary of Data Requirements 46
6.3 General Considerations 46
6.4 Monitoring Methods 49
6.5 Exposure Factor/Questionnaire Information 54
6.6 Estimation of Transfer Coefficients 54
7.0 APPROACH FOR ESTIMATING DIETARY INGESTION EXPOSURE 57
7.1 Introduction 57
7.2 Summary of Data Requirements 58
7.3 General Considerations 58
7.4 Monitoring Method 59
7.5 Exposure Factor Information 60
8.0 APPROACH FOR ESTIMATING INDIRECT INGESTION EXPOSURE 62
8.1 Introduction 62
8.2 Summary of Data Requirements 62
8.3 General Considerations 63
8.4 Monitoring Methods 64
8.5 Exposure Factor Information 67
9.0 OTHER DATA COLLECTION 72
9.1. Questionnaire Data To Identify Sources and Usage of Pesticides in Residences
and Daycares 72
9.1.1 Introduction 72
9.1.2 Administering Questionnaires 72
9.1.3. Information on Sources to be Collected in Pesticide Exposure
Measurement Studies 73
9.1.4 Information on Microenvironment Surfaces, the Structure and the
Occupants 77
9.1.5 Additional Data Collection for SHEDS-Pesticide Model 77
10.0 REFERENCES 79
APPENDIX A - Description of the ORD/NERL Stochastic Human Exposure and Dose
Simulation Model for Pesticides (SHEDS-Pesticides)
APPENDIX B - Food Diary and Questionnaires
VI
-------
Figures
Figure 2-1. Conceptual model of children's residential exposure to pesticides. 10
Figure 3-1. Conceptual model of pesticide exposure by the ingestion route 24
Figure 5-1. Example of one page of the Indoors at Home section of a 24-h time-activity diary
for estimating inhalation and dermal exposure of young children 41
Figure 8-1. Examples of data required for assessing indirect ingestion exposure and sample
questions 68
Figure 8-2. Examples of questions included in the NERL Hygiene and Dietary Habit Survey
(included in Appendix B) 70
Figure 9-1. Example questions use to collect information on pesticide usage in a residence. 74
Figure 9-2. Questions on occupational exposure to pesticides 76
vn
-------
Table 2-1.
Table 2-2.
Table 3-1.
Table 4-1 .
Table 4-2.
Table 4-3.
Table 5-1.
Table 5-2.
Table 5-3.
Table 6-1 .
Table 6-2.
Tables
Definitions Related to Aggregate Exposure Assessments ................... 6
Pathways for Children's Non-Occupational Exposure to Pesticides .......... 12
Summary of Data Collection Requirements by Exposure Route ............. 18
Scenario for Protocol Development ................................... 31
Relevant Age-Related Developments (From U.S. EPA, 2000b) ............. 32
Behavioral Age Bins (From U.S. EPA, 2000b) .......................... 33
Data Requirements for Estimating Inhalation Exposure Route .............. 36
Ranges of Inhalation Rates (g) for "Normal" Female Children and Adolescents on
a per Body Mass Basis by Generalized Type of Activity (L min"' kg'1 ) ....... 43
Ranges of Inhalation Rates (E) for "Normal" Male Children and Adolescents on a
per Body Mass Basis by Generalized Type of Activity (L min"1 kg"1 ) ........ 44
Data Requirements for Estimating Dermal Exposure With the Macroactivity
Approach [[[ 47
Microenvironment/Macroactivity Combinations for Estimating Dermal Exposure
[[[ 48
Table 6-3. Microenvironments/Macroactivity Combinations and Surfaces for Which Activity
Data Are Collected .............................. .................. 55
Table 7-1. Data Requirements for Estimating Dietary Ingestion Exposure ............. 58
Table 7-2. Method Detection Limits and Pesticide Recoveries" from Medium Fat Composite
Diet Samples Fortified at 1 , 5 and 10 ng/g .............................. 61
-------
Acknowledgment
The authors would like to thank Dr. Valerie Zartarian and Dr. Thomas McCurdy of the
U.S. Environmental Protection Agency for their contributions to the protocol. The authors also
wish to acknowledge the contributions of Ross Highsmith, Dr. Daniel Vallero, and other staff in
the Human Exposure and Atmospheric Sciences Division who have been involved in the work
on the Human Exposure Measurements - Children's Focus research program.
IX
-------
1.0 INTRODUCTION
1.1 Background
The U.S. Environmental Protection Agency (U.S. EPA) has pledged to increase its efforts
to provide a safe and healthy environment for children by ensuring that all EPA regulations,
standards, policies, and risk assessments take into account special childhood vulnerabilities to
environmental toxicants.
In evaluating environmental health risks to children, it is important to understand that
children are not little adults. Children's exposures to environmental contaminants and consumer
products are expected to be different and, in many cases, much higher than older individuals.
These differences in exposure are due to differences in physiological function and surface to
volume ratio. Children's behavior and the way that they interact with their environment may
have a profound effect on the magnitude of their chemical exposures. Children crawl, roll, and
climb over contaminated surfaces, resulting in higher dermal contact than would be experienced
by adults in the same environment. Children's mouthing activities (hand-to-mouth and object-to-
mouth) will result in indirect ingestion of chemicals if the hands or objects are contaminated.
Increased indirect ingestion of contaminants also occurs when children handle and eat foods that
have come in contact with the floor or other contaminated surfaces.
In order to articulate the problems and research needs associated with children's exposure
to environmental pollutants, the EPA Office of Research and Development (ORD) developed the
Strategy for Research on Environmental Risks to Children (U.S. EPA, 2000a). This strategy is
centered on the child with the overall goal of improving risk assessments for children and
reducing those risks. Within the Children's Risk Strategy three specific objectives have been
formulated to (1) make use of existing information to develop improved risk assessment methods
and models for children; (2) design and conduct research on exposure, effects, and dose-response
that will answer questions about age-related differences in exposure and risks and that will lead
to better risk assessments for children; and (3) explore opportunities for prevention and reduction
of risks to children.
ORD also conducts research related to children's exposure in support of the Food Quality
Protection Act (FQPA) of 1996. FQPA requires EPA to upgrade the risk assessment procedures
for setting pesticide residue tolerances in food by considering the potential susceptibility of
infants and children to both aggregate and cumulative exposures to pesticides. Aggregate
exposures include exposures from all sources, routes and pathways for individual pesticides.
Cumulative exposures include aggregate exposures to multiple pesticides with the same mode of
action for toxicity. Very importantly, FQPA requires that risk assessments must be based on
exposure data that are of high quality and high quantity or exposure models using factors that are
based on existing, reliable data.
-------
Currently, the data on children's exposures and exposure factors are limited and generally
not adequate to assess residential exposures to consumer products and environmental
contaminants. Several general areas of research are needed to improve the quality and quantity
of data available for exposure assessments for children. Appropriate age/developmental
benchmarks for categorizing children in exposure assessments must be identified. The activity
pattern data for children (especially young children) required to assess exposure by all routes
need to be developed. Methods for measuring children's exposures need to be developed and
improved. Finally, field studies are needed to develop distributions of exposure and associated
exposure factors.
The Children's Exposure Research Program at the EPA National Exposure Research
Laboratory (NERL) is designed to meet several of the above research needs. Research in support
of FQPA has been conducted to: (1) identify those pathways and activities that represent the
highest potential exposures; (2) determine the factors that influence exposures; (3) develop
approaches and methods for measuring and assessing aggregate exposures that account for
children's activities; (4) develop distributional data on aggregate exposures; and (5) generate data
on multimedia pesticide concentrations, pesticide biomarkers, and exposure factors that can be
used as inputs to aggregate exposure models for exposure assessment.
1.2 Purpose
The overall goal of this document is to provide guidance for generating data that can be
used to improve exposure assessments for young children, as required by FQPA. Typically,
exposure assessments are conducted using either a measurement-based approach or a modeling-
based approach. Data requirements for both types of assessments are addressed in this document.
Exposure assessments for FQPA must consider pesticide exposures of infants and
children from all sources and all potential exposure media, including those from food, water,
dust, soil, and air. The definition of a complete and reliable data set for pesticide exposures of
children was provided in Exposure Data Requirements for Assessing Risks from Pesticides
Exposure of Children (U.S. EPA, 1999a). As specified in that document, an exposure
assessment should include the following four elements:
1. An initial screening-level exposure assessment to identify all important sources and
pathways of exposure for the pesticide.
2. An initial assessment to identify the age groups that are at the greatest risk from aggregate
pesticide exposures.
3. Protocols for measuring exposure for all relevant pathways and age groups. Protocols
should include:
• the algorithms for combining the environmental monitoring data with exposure
factor data to estimate an exposure,
• a description of the environmental media that should be measured,
-------
• standard methods for measuring pesticides in those environmental media,
• a description of the activity patterns and exposure factors required, and
• methods for collecting data for all of the relevant activity pattern and exposure
factors.
4. An aggregate exposure assessment using probabilistic multimedia, multipathway models
to develop population exposure distributions.
Currently, standard protocols for conducting exposure field studies that provide data for
measurement-based exposure assessments (element 3) do not exist. Likewise, protocols for
developing exposure factor data to be used for modeling assessments are not available. Although
research on children's exposure to pesticides and other toxic chemicals is being performed within
EPA, academia, industry, and other research organizations, protocols that have been developed
by individual researchers for specific studies do not always collect all of the data required for
reliable exposure assessments, and the data collected cannot always be interpreted.
The purpose of this document is to address element 3, as described above. This
document is a draft protocol that provides approaches and methods that can be used for: (1)
conducting field studies to collect exposure data, (2) developing exposure factor data, and (3)
interpreting data to estimate exposure.
The methods, measurements, and modeling research conducted by NERL in support of
FQPA serves as the basis for this document. The focus of this document is to provide a draft
protocol for measuring aggregate exposures for children from residential uses of pesticides
and/or for collecting data on exposure factors. However, the document is also intended to
provide basic insights into data requirements and approaches for assessing children's aggregate
and cumulative exposure and may be generalized to many environmental pollutants.
1.3 Scope
This document presents a draft protocol for measuring children's exposure to pesticides
by all relevant pathways. It addresses approaches and methods for measurements of children's
exposure that can be used as part of field monitoring studies. The protocol describes the
algorithms for each route of exposure, specifies the data required to conduct the aggregate
exposure assessment, and describes methods for collecting the data. The approach is provided
for estimating exposure by each route. References are provided to assist the reader in obtaining
detailed information on the utility of measurement methods, procurement of materials and
supplies, and implementation in the field.
There are a number of elements of an exposure measurement study that are not addressed
in this protocol because they are specific to the study objectives and study design and are beyond
the scope of this document. For example, this document does not discuss sample selection and
participant recruitment. The survey design is a critical, and very complex, element of any
-------
exposure study, but discussion of this study element is beyond the scope of this document. The
protocol also does not address screening methods that may be used to identify potentially highly
exposed sub-populations or environments. Because the methods in the protocol should be
applicable to a wide range of pesticides and to selected environmental contaminants with a
variety of analytical requirements, analytical methods are not discussed in the protocol. The user
of the protocol will need to identify and use the appropriate analytical methods to measure the
compounds of interest after collection.
This is a draft protocol that does not specify the detailed methods to be used for data
collection. A number of research studies are on-going or planned that will be used to further
evaluate the protocol, data collection methods, and questionnaires to be used in future children's
exposure measurement studies. Results of these studies will be used to refine the protocol and to
develop detailed specifications for approaches and methods.
1.4 Format of the Document
The document is organized to provide general information on exposure and a modeling
framework for addressing children's exposure. Information is given on the algorithms and
methods for collecting data on exposure and exposure factors. Specific sections are as follows:
• Section 2 discusses the basic concepts of exposure including definitions. It also provides
a framework for conducting measurement studies for aggregate exposure assessments.
• Section 3 gives proposed exposure algorithms along with explicit data requirements for
each route of exposure.
• Section 4 describes the exposure scenario addressed by this draft protocol.
• Sections 5 through 8 describes approaches for measuring exposure by various routes and
pathways.
• Section 9 discusses other data collection methods including questionnaires.
• Section 10 includes references cited in the document.
-------
2.0 BASIC CONCEPTS OF AGGREGATE EXPOSURE
The purpose of this chapter is to first define the concepts of exposure. The reader is then
introduced to the basic framework that NERL has been using to develop a protocol that defines
both approaches and methods for measuring exposure and exposure factors in field studies.
2.1 Definitions
Exposure is defined as the contact (at visible external boundaries) of an individual with a
pollutant for specific durations of time. For exposure to occur, environmental media must be
contaminated with a pollutant, an individual must be in the same microenvironment with the
contaminated media, s/he must come in contact with a contaminated medium, and the contact
activity must cause a transfer of the contaminant from the media to the portal of entry of the
individual.
Children's exposure to environmental contaminants is a complex process that may occur
from several sources through a number of different pathways and routes. Sources include all
uses of a chemical that could result in children's exposure. Within this document, only
nonoccupational exposures to environmental contaminants are considered. Route of exposure
(i.e., dermal, oral, inhalation) is defined as the portal of entry. There are three routes of
exposure: the skin is the portal of entry for the dermal exposure route; the mouth is the portal of
entry for the ingestion exposure route, and the lung is the portal of entry for the inhalation
exposure route. Pathway is defined as the course that the contaminant takes from its source to
the portal of entry, hi some cases, we have simplified the pathways to only include the
contaminated exposure media and route of exposure. Exposure pathways include those that
occur indoors and outdoors at the home and at other institutional and non-residential settings
(e.g., schools and daycare centers). Aggregate exposure is the combined exposures to a single
chemical from all sources across all routes and pathways.
Exposure Factors are the factors related to human behavior and characteristics that
determine an individual's exposure to a pesticide or contaminant. For example, an individual's
exposure to a pesticide by the inhalation route is determined by factors that include the duration
of time spent in different microenvironments during the day and the individual's inhalation rates
during the period of exposure.
Other definitions used in this document that are pertinent to conducting aggregate
exposure assessments are given in Table 2-1.
2.2 Measurement Methods Versus Approaches
Traditionally, exposure measurement studies have been based on using a set of methods
to measure contaminants in environmental media. Questionnaires and diaries are then used to
-------
Table 2-1. Definitions Related to Aggregate Exposure Assessments
Term
Acute exposure
Aggregate exposure
Approach
Biomarker of
exposure
Chronic exposure
Cumulative
exposure
Exposure
Exposure algorithm
Exposure factors
Exposure pathway
Exposure route
Exposure scenario
Definition
An exposure period of less than one day.
The combined exposures to a single chemical from all sources across
all routes and pathways.
The process for combining data from single determinants to estimate
exposure.
Exogenous chemicals, metabolites, or the products of interactions
between a chemical and target molecules or cells that are measured
within a compartment or within an organism. This includes internal
dosimeters of a chemical or metabolite concentrations and markers of
biologically effective doses.
An exposure presumed to occur over a substantial portion of the
individual's lifetime.
The total exposure to chemicals that cause a common toxic effect(s) to
human health by the same, or similar, sequence of major biochemical
events.
The contact (at visible external boundaries) of an individual with a
pollutant for specific durations of time.
A mathematical expression of the approach. It expresses exposure as a
function of pesticide concentration in the exposure medium, contact
rate, rate of transfer from the exposure medium to the portal of entry,
and exposure duration.
The factors related to human behavior and characteristics that
determine an individual's exposure to a pesticide or contaminant. For
example, duration of exposure, inhalation rates, transfer coefficients.
The course that the chemical takes from its source to the receptor's
portal of entry.
The portal of entry of a chemical into the body.
The combination of facts, assumptions, and inferences that define a
discrete situation or activity where potential exposures may occur.
These include the source, the exposed population, the time frame of
exposure, microenvironment(s), and activities.
-------
Term
Intermediate-term
exposure
Macroactivity
Method
Microactivity
Microenvironment
Pathway
Short-term exposure
Transfer coefficient
Transfer efficiency
Transferable surface
residue
Total surface
loading
Definition
An exposure lasting from one week to several months.
Aggregated series of contact events in the same microenvironment and
the same activity level.
A process for measuring a single determinant such as an environmental
concentration of a pesticide or an activity frequency.
Individual skin-to-surface or object-to-mouth contact event.
A space or location defined for dermal exposure on the basis of
specific surface types that may be contacted (e.g., indoors at home on
carpet). For inhalation exposure, it is defined as an air space with a
homogenous concentration of the chemical.
The course that the contaminant takes from its source to the portal of
entry.
An exposure lasting from one to seven days.
A measure of contaminant transfer resulting from contact of an object
or skin with a contaminated microenvironmental surface while engaged
in a specific macroactivity, expressed as surface contact area per unit
time (cnrVh).
The fraction of mass transferred from a contaminated surface to skin,
food, or other object per unit contact (unitless).
The mass of contaminant per unit area (ug/cm2) measured by a
standard transfer method.
The total mass of contaminant per unit area (ug/cm2).
collect information on activities and locations. Often a systematic selection of methods and
questions is not developed and the resulting data cannot be used to estimate exposure by multiple
routes and pathways. Within this document, the emphasis is on the use of approaches to estimate
exposure rather than the application of a set of methods. Such a process first determines how
exposure for each route will be estimated, then defines the data needed, and finally identifies
specific methods for data collection.
-------
Within this protocol, a method is defined as a process for measuring a single determinant
such as an environmental concentration of a pesticide or an activity frequency. An approach
defines the process for combining data from single determinates to estimate exposure. The
exposure algorithm defines the approach. For each route, the algorithm mathematically
expresses exposure as a function of pesticide concentration in the exposure medium, contact rate,
rate of transfer from the exposure medium to the portal of entry, and exposure duration.
Consequently, the exposure algorithm describes the specific data needs for estimating exposure
and the process for combining the data. This protocol describes both methods for the single
determinants and the algorithms for estimating exposure by each pathway and route.
2.3 Exposure Assessment
Typically, exposure assessments are conducted using either an individual measurement-
based approach or a population modeling-based approach. For simplicity, these will be referred
to as measurement and modeling assessments throughout this document. Data requirements and
measurement study designs will vary for the two approaches. This document emphasizes data
collection methods and approaches for measurement-based assessments.
Measurement assessments measure the contact of the individual with the chemical in
the exposure media over an identified period of time. Direct assessments are made through field
monitoring studies of children in their everyday environments. In such studies, data are collected
on pollutant concentrations in a variety of exposure media (i.e., air, drinking water, food, house
dust, surface residues), activities, and exposure factors so that exposure can be measured or
estimated for each child in the study. Often pesticides or their metabolites are analyzed in
biological media as a direct measure of exposure aggregated over all sources and pathways for a
given time period. A comparison of exposure estimated from measurement assessments to
exposure estimated with biomarkers often provides a evaluation of both approaches. For
measurement assessments, it is imperative to collect all of the data on exposure media
concentrations, activities, and exposure factors that are required to quantify exposure for an
individual using the exposure algorithms for each route and pathway.
Modeling assessments use available information on concentrations of chemicals in
exposure media along with information about when, where, and how individuals might contact
the exposure media. The modeling approach then uses models and a series of exposure factors
(i.e., contact duration, contact frequency, contaminant transfer) to estimate exposure. For
modeling assessments, distributional data on exposure factors and environmental concentrations
are used to estimate exposure distributions for a population. However, the data do not need to be
collected on the same individuals. For the modeling approach, studies can be conducted to
obtain data for only a single exposure factor or a combination of exposure factors. No attempt is
made to actually measure or estimate exposure for the individual participants in the study with
the modeling approach. Data on activities and exposure factors collected as part of a
measurement assessment can also be applied to modeling assessments.
8
-------
2.4 Framework for Exposure Assessment
Aggregate exposure includes exposure from all sources, routes and pathways for
individual pesticides. Given this definition, a comprehensive approach is required to understand
and adequately address all of the components of an aggregate exposure assessment. NERL has
developed a framework to systematically identify the important sources, routes, and pathways for
exposure (Cohen Hubal et ah, 2000). This framework is based upon the development of a
conceptual model for aggregate exposure and provides the basis for developing a protocol to
measure and assess aggregate exposures, as well as for developing sophisticated stochastic
models. This framework also allows us to systematically identify the most critical research needs
and data gaps associated with children's exposures to pesticides. The steps of the framework are
as follows:
1. Develop a model that describes aggregate exposure,
2. Identify potential exposure pathways and scenarios,
3. Define algorithms, exposure factors, and data requirements for each route,
4. Develop a probabilistic model for assessing aggregate exposure,
5. Perform a screening assessment to evaluate the range of exposures for, and significance
of, each pathway,
6. Identify critical data gaps in the assessment process, and
7. Conduct field studies to address data gaps and reduce uncertainty.
Steps 1 through 3 have been critical in the development of this protocol. Steps 4,5, and 6 have
been used to identify research needs. The protocol developed here will be applied to studies in
step 7.
Although the emphasis of this protocol is on measuring and assessing residential pesticide
exposure to infants and young children, this same framework could be adapted for other
exposure scenarios.
Model. A conceptual model of children's residential exposure to pesticides was
developed by NERL that was the initial focal point for the research strategy and protocol
development. This conceptual model (Figure 2-1) shows the exposure process from source to
absorbed dose for all routes of exposure. 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 micro-
environment to another (e.g., yard to house). Exposure occurs once a human contacts a
contaminated exposure medium and the contaminant is transferred from the medium to the portal
of entry. Exposure is a function of the time spent in the microenvironment of interest, contact
rate, and the mass transfer of pesticide from the exposure medium to the portal of entry.
Contacts rates and mass transfer are a function of human activity patterns (indicated by the
shaded ovals). Finally, uptake of the pesticide through the respiratory tract, the skin, or the
-------
k
• -o
o
pa
•o
u
,£> O
t* CO
0 0
<
,.
1 _
(^
V N,
00
-8
• 1—4
O
I
(U
13
I
1
o
V
u
^^ I—1 vw
illll!
^ w ti w ^ b.
*-* W3 'S W *O
.s 22 § e .s
•c
60
10
-------
gastrointestinal tract will result in an absorbed dose.
Exposure Pathways. The conceptual model was used to systematically identify all
potential exposure pathways. In general terms, a pathway is defined as the course that a pesticide
takes from its source to the receptor's portal of entry. However to specifically evaluate potential
for exposure, simplified pathways were defined by the exposure medium and the route of
exposure. Essentially, the evaluation focused on exposure, without considering transport of the
pesticide to the exposure medium. Using this simplified definition, the pathway crosses the
activity with the exposure medium that leads to exposure. For example, inhalation (activity) of
indoor air (exposure medium) is one pathway, and dermal contact (activity) with turf (exposure
medium) is another pathway. A comprehensive list of potential pathways was developed and is
presented in Table 2-2.
Exposure Algorithms. Algorithms were developed to assess exposure by each route.
The algorithm mathematically expresses exposure as a function of pesticide concentration in the
exposure medium and various exposure factors, including contact rate, rate of transfer from the
exposure medium to the portal of entry, and exposure duration. As described in Section 3,
exposure algorithms are also used to describe the data requirements for each route in field
monitoring studies to assess exposure using the measurement-based approach.
Time Frame for Exposure Measurements. Risk assessments must take into account
the frequency and duration of exposure, as well as its magnitude. In pesticide risk assessments,
four exposure durations generally are considered. Acute exposure is defined as an exposure
period of less than one day. Exposures through food and drinking water have been included in
acute exposure assessments. Short-term exposure is defined as an exposure lasting from one to
seven days. Possible short-term exposures to pesticides in and around the home could come
from uses such as on lawns and home gardens, as a crack and crevice treatment for
insects, a treatment for carpets or other surfaces, or a flea treatment for pets. Other short-term
exposures could occur in public places such as parks, school playgrounds, and playing fields.
Data indicate that post-application exposures from these uses typically last from a day to several
weeks. Intermediate-term exposure is defined from one week to several months. Possible
intermediate-term exposures to pesticides in and around the home could occur due to use of
rodenticides as well as some of the exposure scenarios described above in the acute and short-
term categories. Chronic exposure is presumed to occur over a substantial portion of the
individual's lifetime. Although chronic exposure can occur via all routes and pathways, dietary is
considered to be the largest component. Pesticides, such as those used as termite control, could
also result in chronic exposures.
Exposure Scenarios. For any given pathway, a set of associated exposure scenarios can
be described. An exposure scenario is defined by the combination of:
Source or application method (e.g., crack and crevice application of pesticides, residential
11
-------
Table 2-2: Pathways For Children's Non-occupational Exposure to Pesticides
Exposure Medium
Route
OUTDOOR PATHWAYS
Pesticide pellets and
granules
Outdoor air
Outdoor water
a) natural water body
b) swimming pool
Soil
Plants
a) turf
b) gardens
c) fruit on trees
Outdoor surfaces/objects
a) paint chips
b) concrete
c) toys, furniture, tools, etc.
Ingestion (direct)
Dermal contact
Ingestion (hand-to-mouth)
Inhalation
Dermal contact
Ingestion of particles
Dietary ingestion
Dermal contact (e.g. ,while swimming)
Ingestion (direct e.g., while swimming)
Inhalation of vapors (e.g., while swimming)
Ingestion (direct)
Indirect ingestion (object-to-mouth, hand-to-mouth)
Dermal contact
Ingestion (direct)
Indirect ingestion (object-to-mouth)
Dermal contact
Indirect ingestion (hand-to-mouth)
Indirect ingestion (object-to-mouth)
Dermal contact
Indirect ingestion (hand-to-mouth)
INDOOR PATHWAYS
Indoor air
Indoor water
Inhalation
Dermal contact
Ingestion of particles
Dietary ingestion
12
-------
Exposure Medium
Food
Indoor objects/surfaces:
a) carpeted surfaces
b) hard surfaces
c) upholstery and bedding
d) toys
House dust
(Includes tracked in soil)
Route
Dermal contact (e.g., showering)
Inhalation of vapors (e.g., showers, dishwashers, etc.)
Dietary ingestion (food contaminated with agricultural residues)
Indirect ingestion (food contaminated by contact with contaminated
residential surfaces)
Indirect ingestion (food contaminated by contact with contaminated
hands)
Indirect ingestion (object-to-mouth)
Dermal contact
Indirect ingestion (hand-to-mouth)
Ingestion (direct)
Indirect ingestion (object-to-mouth, hand-to-mouth)
Dermal contact
OTHER PATHWAYS
Pets
Material impregnated with
pesticides
Clothes
Dermal contact
Indirect ingestion (hand-to-mouth)
Dermal contact
Indirect ingestion (hand-to-mouth)
Indirect ingestion (object-to-mouth)
Inhalation of vapors
Dermal contact
Indirect ingestion (hand-to-mouth)
Indirect ingestion (object-to-mouth)
13
-------
use of consumer product, lawn and garden applications, agricultural use),
• Exposed population (e.g., age group, geographical location),
• Time frame of exposure (acute, short term, chronic), Microenvironments for exposure,
and
• Activity that results in exposure.
When exposure assessments are conducted by the modeling approach, specific exposure
scenarios determine the values of the exposure factors that should be used in the algorithms to
estimate exposures. For measurement assessments, field studies are conducted to assess
exposure for individual participants. For these studies, the participants actually define the
scenario based on their everyday activities. Field studies can be conducted on a general
population to understand distributions of exposures and exposure factors and the relationship
between various exposure factors. These studies can also provide information to determine what
scenarios actually exist hi the population and to aid in selecting the most appropriate scenarios
for modeling assessments. Alternately, studies can be conducted to evaluate exposure and
exposure factors for predefined scenarios. In either case, it is necessary to collect all of the data
that are needed to adequately define the scenario and the exposure factors that are used in the
algorithm for that scenario.
NERL has used the conceptual model discussed here to develop the Stochastic Human
Exposure and Dose Simulation Model for Pesticides (SHEDS-Pesticides). SHEDS is a
probabilistic multi-media, multi-pathway model (Zartarian et. al, 2000) that is designed to
develop probability distributions of exposure and to also estimate inter-individual variability in
the population and uncertainty in the estimated empirical exposure and dose distributions. The
model is described in Appendix A of this document. Measurement data collected with the
protocol described in this document will be used as inputs and for evaluation of the SHEDS-
Pesticides model. Results of the sensitivity and uncertainty analyses conducted with SHEDS-
Pesticides will be used to further refine the protocol for the exposure measurements. Hence,
SHEDS-Pesticides will be used in an iterative fashion with the conceptual framework presented
here to refine the protocol.
14
-------
3.0 EXPOSURE ALGORITHMS AND DATA REQUIREMENTS
The purpose of this chapter is to present the exposure algorithms that have been
developed for assessing exposure by each route and pathway. The data requirements associated
with the algorithms are also given. Details of the methods to collect these data are presented in
subsequent chapters.
3.1 Exposure Algorithms
Exposure algorithms have been developed to assess exposure by each route. The
algorithms are used here to determine a priori what data must be collected in field studies to
quantify exposure. Thus, the algorithms provide a convenient framework for developing and
using field monitoring methods.
Although it is convenient to identify pathways by first considering the exposure medium
and then considering the route, the associated exposure algorithms are route specific. Aggregate
assessments for children must include all three exposure routes: inhalation, dermal contact, and
ingestion. In addition, ingestion can be divided into two important subroutes, dietary and indirect
ingestion [i.e., ingesting pesticides from contaminated objects (including food) and hands placed
in the mouth].
The exposure algorithm defines the measurement approach. For each route, the algorithm
mathematically expresses exposure as a function of pesticide concentration in the exposure
medium, contact rate, rate of transfer from the exposure medium to the portal of entry, and
exposure duration. The basic components of the algorithm are used to define the monitoring,
activity pattern, and source usage data that must be collected to estimate exposure.
Algorithms are applied separately to all of the microenvironments and activities that an
individual experiences in a given time period. Within this document, microenvironment is
referred to as the location where an individual spends time. For inhalation exposure, Duan
(1982) defined a microenvironment as "a [portion] of air space with homogeneous pollutant
concentration." It has also been defined as a volume in space, for a specific time interval, during
which the variance of concentration within the volume is significantly less than the variance
between that microenvironment and surrounding microenvironments (Mage, 1985). For dermal
exposure, microenvironment has been defined based upon the location and surface type.
Homogeneity of the surface concentration has been considered within the algorithms.
Activities are defined as either macroactivities or microactivities. Macroactivity is a
series of contact events in the same microenvironment and the same activity level that are
aggregated for the purposes of estimating dermal exposure. The macroactivity approach has
been used extensively for estimating worker exposures to pesticides. For children, an example of
a macroactivity would be lying on a carpeted floor for one hour watching television in the family
15
-------
room. Microactivities are defined as discrete, individual, skin-to-surface or object-to-mouth
events, such as when a child puts a toy in his/her mouth.
Exposure models for assessments use one of two general approaches: a time-series
approach that estimates microenvironmental exposures sequentially as individuals go through
time, or a time-averaged approach that estimates microenvironmental exposures using average
microenvironmental concentrations and the total time spent in each microenvironment. The
tune-series approach to modeling personal exposures provides the appropriate structure for
accurately estimating personal exposures (Esmen and Hall, 2000; Mihlan et al., 2000). In
addition, the time-varying dose profile of an exposed individual can be modeled only by using
the time-series approach (McCurdy, 1997,2000). However, a time-averaged approach is
typically used since the input data needed to support a time-series model are usually not available
or cannot be easily collected. Real-time monitoring techniques for measuring pesticide
concentrations are very limited. Most environmental monitoring provides either an integrated
24-hour concentration (as in air or duplicate diet samples) or a single time-point concentration
(as in transferable residue samples). Thus, the algorithms presented here use a time-averaged
approach over a 24-hour period. They could, however, be modified to provide time-series data,
especially for activity patterns.
Approaches for aggregating exposure estimates across routes are not presented here.
Since absorbed dose may be different depending upon the route, it is not appropriate to sum
exposure across routes. Exposure for each route is estimated independently. These exposures
can then be used as inputs to exposure/dose models to estimate dose. The algorithms presented
here are similar to those used elsewhere in the literature (U.S. EPA, 1997a; U.S. EPA 1997b).
3.2 Inhalation Route
Inhalation exposure may result from pesticides applied indoors or due to infiltration of
pesticides applied adjacent to buildings. Although current use pesticides, such as the pyrethroids,
are generally less volatile than many of the pesticides previously used indoors (e.g., chlorpyrifos),
they may be detected in the air following application.
Exposure Algorithm. Inhalation exposure is estimated for each of the micro-
environments where a child spends time and each macroactivity that would result in a different
inhalation rate while engaging in that activity. Exposure over the 24-hour period is then the sum
of all of the microenvironmental/macroactivity (me/ma) exposures. This may be expressed
mathematically as:
Ei24 = EEime/ma 0)
where
Ei24 = the total inhalation exposure over a 24-hour period (ug/d)
16
-------
me inhalation exposure for a given me/ma over a 24-hour period (ug/d)
For each me/ma, inhalation exposure over the 24-hour period (Eirae/mJ is defined as:
= ^ame X Tme/ma X IR^ (2)
where
^ame = the air concentration measured in the micro environment (|ag/m3)
Tme/ma = the time spent in that me/ma over the 24 hour period (h/d)
IRjna = the child's inhalation rate representing his activity level for that
macroactivity (m3/h)
Data Requirements. In order to apply the above model, the following data are required:
• Definition of the important microenvironments/macroactivities for inhalation
exposure. Four generalized microenvironments have been defined for very young
children (4 years old and younger). These include indoors and outdoors at home and
indoors and outdoors at daycare centers. If the air concentrations indoors are not
homogenous, there may be more than one microenvironment indoors at home or indoors
at daycare. There may also be other indoor and other outdoor microenvironments that
are important if the child spends substantial amounts of time away from the home or
daycare. Four macroactivities have been defined for children: sleeping/napping, active
play, quiet play, and eating.
• Air concentration in each microenvironment. Ideally, an integrated air concentration
should be measured only during the time that the subject is in each microenvironment.
Alternatively, an integrated 24-hour measurement should be adequate if it is assumed that
air concentrations do not vary substantially over time or space within any
microenvironment. Since the air concentration for the other indoor and other outdoor
categories will not be measured, an approach for developing a reasonable estimate must
be made. This estimate becomes important for inhalation exposure if the subject spends
substantial time in these other microenvironments.
• Amount of time the child spends in each me/ma over 24-hours. The amount of time a
child spends in each microenvironment/macroactivity is collected with a tune-activity
diary for the period of monitoring. The diary, at a minimum, should record the child's
time in each microenvironment and information on the child's activities that can be used
to estimate inhalation rate while in that microenvironment.
• Inhalation rate for each me/ma. The rate of inhalation will be estimated based on age
and weight of the child and activity in each microenvironment.
Table 3-1 summarizes the data requirements as they relate to equation (2) to estimate
exposure by the inhalation route.
17
-------
Table 3-1. Summary of Data Collection Requirements by Exposure Route
Parameter
Measurement
How Collected
Units
Inhalation Exposure
kjme/ma ~ ^-'amts X ^ me/ma X "Sna
cm
T
* me/ma
IRma
Air concentration in me
Time spent in each
me/ma
Inhalation rate
Measured with active sorbent
collection
Time-activity diary, questionnaire
Estimated from size, age, and
activity data collected with diaries
and questionnaires using reference
values
ug/m3
h/d
m3/h
Dermal Exposure - Macroactivity Approach
^dme/ma = ^sarf X TCme/ma X ADmetoa
Csurf
'•Cme/mz
ADme/ma
Surface loading (total or
transferable) in each me
Transfer coefficient"
Activity duration for ma
in a specific me
Measured by wipe, press, or roller
methods
Empirically determined for each
me/ma from laboratory
experiments or field studies
Time-activity diary, questionnaire
Hg/cm2
cnrVh
h/d
Dermal Exposure - Microactivity Approach
E.W = CsurfxTExSAxEF
Csurf
TE
SA
EF
Surface loading (total or
transferable) in me
Transfer efficiency8
Surface area contacted
Frequency of contact
events
Measured by wipe, press, or roller
method
Empirically determined from
laboratory experiments
Visual observation or videotape
Visual observation or videotape
ug/cm2
unitless
cm2/event
events/d
Dietary Ingestion Exposure
Ef = S CfWf
cf
Concentration of pesticide
in the food item (s)
Measurement in individual food
items or composite duplicate diet
samples
ug/kg
18
-------
Parameter
wf
Measurement
Weight of food item
consumed
How Collected
Measured in duplicate diet sample
Units
kg/d
Indirect Ingestion Exposure - Microactivity Approach
Eingmi = CxxTExxSAxxEF
Csurfc
TEX
SAX
EF
Surface loading (total or
transferable) on object x
Transfer efficiency*
Surface area contacted
Frequency of mouthing
events
Measure by a wipe or press
method
Empirically determined from
laboratory experiments
Visual observation or videotape
Visual observation or videotape
Hg/cm2
unitless
cm2/event
events/d
* This parameter must be calculated using the same surface loading measurement method as used to
measure C
3.3 Dermal Route
Two main approaches are currently used to assess dermal exposure. These assessment
approaches provide different ways of integrating exposure over time and space. In the
macroactivity approach, exposure is estimated individually for each of the microenvironments
where a child spends time and each macroactivity that the child conducts within that
microenvironment. To do this, exposure is estimated using empirically derived transfer
coefficients to aggregate the mass transfer associated with a series of contacts with a
contaminated medium.
In the microactivity approach, exposure is explicitly modeled as a series of discrete
transfers resulting from each contact with a contaminated medium. To estimate dermal exposure
with the microactivity approach, exposure must be estimated for all contacts made by child
during a 24-hour period. To use the microactivity approach, a substantial amount of detail is
needed to characterize children's dermal contact with chemical residues in all of their
microenvironment/macroactivity combinations and to quantify subsequent dermal absorption.
These data include: definitions of the microenvironments/macroactivities that are important for
dermal exposure; surface loading measurements (total or transferable surface residue) for each
microenvironment/macroactivity combination; amount of time a child spends in each
microenvironment/macroactivity during a 24-h period; the transfer coefficient for each
microenvironment/macroactivity; surface area of exposed skin; contact frequency of exposed
skin in a given microenvironment; and transfer efficiency for each microactivity. Collection of
19
-------
this level of detailed data is extremely resource intensive and not practical in most field
measurement studies. The microactivity approach can be applied in small research studies, but
has limited utility for exposure measurement studies. Therefore, although the algorithm is
described below, methods for collection of the required data are not described in this protocol.
3.3.1 Macroactivity Approach
Exposure Algorithm. To estimate exposure using the macroactivity approach,
microenvironments are defined by location and surface type. Macroactivities (i.e., active play,
quiet play, sleeping/napping, and eating) are defined based on the expected magnitude and
variability of the pesticide transfer coefficient. For any given microenvironment/macroactivity
combination transfer coefficients are developed using carefully controlled laboratory or field
studies. Exposure in field studies can then be estimated individually for each of the
microenvironments where a child spends time and each macroactivity that the child conducts
within that microenvironment using transfer coefficients and the surface loading in the
microenvironment. The surface loading may be either the total residue concentration present on
a surface or the amount of pesticide residue on the surface that is available for transfer to the skin
(referred to as the transferable residue). Different methods are used to make the measurements of
these two categories of residues, as discussed in Section 6.0.
Exposure over a 24-hour period is the sum of all the microenvironment/macroactivity
exposures, expressed as:
where
dermal exposure over a 24-h period for all microenvironments and
macroactivities (jig/d)
dermal exposure for a given microenvironment/macroactivity combination
For each microenvironment/macroactivity combination, dermal exposure is defined as :
Edme/ma = (Csurf)(TCme/ma)(ADme/ma) (4)
where
Edme/ma = dermal exposure for a given microenvironment/macroactivity combination
over a 24-h period (p.g/d)
Csurf = surface loading (total or transferable) measured in the microenvironment
(ug/cm2)
TCme/ma = transfer coefficient for the microenvironment/macroactivity (cm2/h)
ADme/ma = activity duration that represents the time spent in each
20
-------
microenvironment/macroactivity combination with a specific clothing
pattern for the child that would affect the surface area available for transfer
over a 24-h period (h/d)
The transfer coefficient, TCme/ma, provides a measure of dermal exposure resulting from
contact with a contaminated microenvironmental surface while engaged in a specific
macroactivity. The transfer coefficient takes into account the fraction of the transferable surface
residue that is transferred from a surface to skin, the character of the microenvironmental surface
that is contacted, and the area of the microenvironmental surface that is contacted during a time
increment for a given activity. Transfer coefficients are empirically derived in laboratory tests or
controlled field experiments. TCder can be defined as follows:
TCme/ma = (Etoe/ma)/(CslJ(ADme/ma) (5)
Data Requirements. Table 3-1 shows the data requirements as they relate to equation
(4) which is used to estimate dermal exposure by the macroactivity approach. The following data
will be required for each microenvironment/macroactivity combination to estimate dermal
exposure:
• Definition of the microenvironments/macroactivities that are considered important
for dermal exposure. These microenvironments/macroactivities account for:
• Various microenvironments with different residue concentrations,
• Various types of surfaces that affect the transfer rate,
• Child activities that affect the transfer coefficient. Macroactivities have been
selected that should have fairly uniform transfer coefficients within a
microenvironment.
• Surface loading. For each microenvironment/surface combination, measurements will
be made on those surfaces for which the child is expected to have substantial contact.
Measurements should provide a representative loading for the entire area of contact. The
measurement may be of total residue or the transferable residue.
• Amount of time the child spends in each microenvironment/macroactivity during a
24-h period. These data can be collected using a time-activity diary or questionnaire.
• Transfer coefficient for each microenvironment/macroactivity. These are data that
are currently not available. NERL is in the process of developing specific children's age
related transfer coefficients in the laboratory and in controlled field experiments.
• Clothing pattern for the child that would affect the surface area available for
transfer. The amount of clothing and exposed skin needs to be determined.
3.3.2 Microactivity Approach
Exposure Algorithm. To assess dermal exposure using the microactivity approach,
exposure is estimated individually for all of the microactivities in a given microenvironment in
21
-------
which dermal contact occurs. Exposure over a 24-h period is then the sum of all of the
individual exposures:
Ederm24 = ZEEdmi (6)
i J
where
Ederm24 = dermal exposure over a 24-h period for all microactivities (ng/d)
i = sumofallmicroenvironments
j = sum of all microactivities in a given microenvironment
Edmi = dermal exposure for each microactivity over a 24-h period (ng/d)
For each microenvironment/microactivity, dermal exposure over a 24-h period can be defined as:
E^i - (Csurf)(TE)(SA)(EF) (7)
where
E^j = dermal exposure for each microactivity over a 24-h period (ng/d)
Csurf = surface loading (total or transferable) measured in the microenvironment
Og/cm2)
TE = transfer efficiency, fraction transferred from surface to skin (unitless)
SA = surface area contacted (cm2/event)
EF = frequency of contact events during a 24-h period (events/d)
Transfer efficiency is defined as the fraction of mass transferred from a contaminated surface to
skin per unit contact and can be represented as follows:
TE = (Lmi)/(Csurf) (8)
where
Lmi = loading (|j.g/cm2) on the transfer medium (i.e., skin)
Data Requirements. To use the microactivity approach, a greater level of detail is
needed to characterize children's dermal contact with chemical residues in their environments.
Given the greater level of detail that is required, the microactivity approach is not used for
directly estimating exposure in field studies. Rather, it is applied to indirect modeling
assessments. Data are usually only collected on exposure factors, most particularly in the form of
videotaping children's activities. Data required to estimate dermal exposure include:
• Definition of the microenvironments that are considered important for dermal
exposure. The microenvironments should account for:
• Various microenvironments with different residue concentrations,
• Various surfaces that affect the transfer rate, and
22
-------
• Clothing worn by the child.
• Contact frequency of exposed skin in a given microenvironment. This is determined
using a videography method or direct visual observations.
• Surface area of skin exposed during contact. Data are collected on a child specific
basis.
• Parameters describing the nature of the contact for each microactivity. Information
should be collected on a child specific basis on those parameters that influence transfer
efficiency from the surface to the skin. Currently, this information is not available;
however, research at NERL is underway to identify these parameters. Potentially
important contact parameters include duration, pressure, motion, and skin surface (sticky,
wet, dry).
• Surface loading at the point of contact. When surface loadings are not homogenous,
data should be collected for every point on the surface where contact is made.
Unfortunately, measurement data in this detail cannot be collected in a field study. Thus
pesticide distributions within each microenviornment must be modeled using data
generated during laboratory experiments or carefully controlled field experiments.
Sufficient field measurement data should be available to verify the modeled distributions.
• Transfer efficiency for each microenvironment and microactivity. These are data that
are currently not available and need to be generated experimentally in controlled
laboratory experiments.
Table 3-1 shows the data requirements as they relate to equation (7).
3.4 Ingestion Route
Characterizing ingestion of pesticides by children may involve several pathways:
• Direct ingestion of foods brought into the home or other eating places containing
pesticide residues primarily from agricultural applications, but also from contamination
during storage and preparation in the residential or other environments (i.e., dietary
ingestion),
• Ingestion of foods that have been contaminated as the result of contact with contaminated
hands and surfaces during preparation and consumption,
• Pesticide residues ingested while mouthing contaminated hands and objects, and
• Ingestion of contaminated soils or contaminated house dust found in the residential or
other environments.
A conceptual model of the potential pathways for ingestion exposure is presented in
Figure 3-1. Ingestion pathways 2 through 4 above are referred to here as indirect ingestion and
may be the result of hand-to-mouth, object-to-mouth, or hand-to-object-to-mouth activity where
the objects may be items such foods contaminated while being consumed or toys contaminated hi
the child's environment as a result of routine activities.
23
-------
Figure 3-1. Conceptual model of pesticide exposure by the ingestion route.
Loss by dislodgement,
degradation, food
preparation, etc.
Loss by
dislodgement
washing, etc. ./
Transfer by mouthing
24
-------
Infants and young children may be particularly vulnerable to exposure by the ingestion
route for several reasons. The specific foods comprising the diets children eat may result hi
higher dietary ingestion of contaminants and children eat more relative to then- body weights than
adults. Indirect ingestion of contaminants may also occur when children handle and eat foods
that have come in contact with the floor or other contaminated surfaces. In many cases, indirect
ingestion may occur after repeated contacts of the same object (food or any other object that
enters the mouth) with multiple contaminated media, and from multiple contacts with the mouth.
For example, a food item may contact several surfaces, including eating surfaces, hands, and
utensils, before it is partially or completely ingested. Finally, children's mouthing activities will
result in indirect ingestion of environmental contaminants if the hands or non-dietary objects
entering the mouth are contaminated.
3.4.1 Dietary Ingestion
To determine the ingestion of pesticides through the dietary pathway, duplicates of all
foods consumed (i.e., duplicate diets) during the monitoring period are collected and analyzed.
In duplicate diet studies for children, a caregiver generally provides second portions (e.g., a
duplicate plate) of the foods given to the child for consumption. The portions are identical to
what has been served to the child with respect to preparation, type of food, and amount of food.
Following the eating activity by the child, portions are adjusted to account for foods not
consumed (e.g., a duplicate diet). The distinction between a duplicate plate (consisting of all
foods served) and a duplicate diet (consisting of all foods eaten) is typically more significant for
children than adults because significant quantities of food may be left uneaten. During the brief
monitoring period for the child, duplicate diet methodology should provide the most accurate
measure of dietary exposure because it accounts for all foods consumed, even those from non-
commercial sources (Thomas et al., 1997). It accounts for gains or losses of the contaminant that
may occur during transport, storage, and preparation, and most importantly, when combined with
methodology to assess indirect ingestion during consumption, measures the actual and total
contaminant intake for the child during the exposure monitoring period.
Duplicate diets are collected over some specific period of time, with one day being the
time increment most often used (i.e., for acute assessment). For longer periods (i.e., short-term,
intermediate term or chronic assessments), multiple consecutive or non-consecutive days may be
used to better describe the child's contaminant intake, since there is the potential for a large daily
intake variability, hi some cases, particularly for risk assessment, it may be necessary to collect
duplicate diet samples at different times of the year to assess seasonal intake variability.
Exposure Algorithm. Assessing the dietary ingestion of a contaminant is estimated by
the sum of the concentration of the contaminants multiplied by the amount consumed of all foods
25
-------
eaten during the monitoring period.
Er - ECfWf (9)
where
Ef = the total dietary ingestion during the 24-hr period (|J.g/d)
Cf = concentration of pesticide in the food item (ug/kg)
Wf = weight of food item consumed (kg/d)
Data Requirements. To assess total contaminant intake, duplicate portions of all foods
and beverages consumed by the child must be collected and analyzed. In selected cases, a study
may focus on the contaminant intake from a single dietary source (e.g., fish or vegetables), and
the duplicate diet methodology can be applied to the specific food or group of foods.
3.4.2 Indirect Ingestion
To date, indirect ingestion has been estimated using two approaches. One approach is
similar to the microactivity approach described in Section 3.3.2 for assessing dermal exposure by
which each contact with a contaminated medium is described (U.S. EPA 1997b, Melnyk et al.,
2000, Akland et al., 2000). A second approach is to measure the concentration of pesticide or
contaminant in soil or house dust and then assume a mass of soil/dust that is consumed by the
child (U.S. EPA 1997b) in association with activities such as mouthing objects or eating foods.
A third approach is proposed here that uses some additional assumptions to lump details
associated with some of the exposure factors and activity patterns leading to indirect ingestion.
This macroactivity-type approach allows for a simplified assessment of indirect ingestion
exposure to an individual based on measurement data collected in the field and factors that
characterize the activities that lead to indirect ingestion of contaminants.
Exposure Algorithm for Microactivity Approach. To assess indirect ingestion
exposure using the microactivity approach, exposure is estimated individually for all of the
microactivities (e.g., hand-to-mouth, object-to-mouth, food-to-mouth, hand-to-food-to-mouth
contacts) in which indirect ingestion occurs. Exposure during the 24-h period is then the sum of
all of the individual exposures:
/mi (10)
where
indirect ingestion exposure during the 24-h period for all microactivities
(ug/d)
indirect ingestion exposure for each microactivity during the 24-h period
26
-------
For each microactivity, indirect ingestion exposure during the 24-h period can be defined as:
Eing/mi = (Csurfe)(TEx)(SAxm)(EF) (11)
where
^ing/mi = indirect ingestion exposure for each microactivity over a 24-h period
Gig/d)
x = hand, object, food item or anything else that enters the mouth
CSUrfx = surface loading (total or transferable) on x (ug/cm2)
TEX = transfer efficiency of contaminant from x to mouth (unitless)
SA^ = area of x contacted by mouth (cm2/event)
EF = frequency of indirect ingestion events over a 24-h period (event/d)
For food or any other item that is ultimately consumed, TEX is equal to unity. When transfer
from x to the mouth is for items other than food, TEX is a function of:
• Characteristics of x (hard, plush, porous, moisture, oil content, age, loading) and
• Contact mechanics (sucking, licking, duration, repetition)
hi addition, the loading of pesticide on an object (e.g., toy or food) contaminated as a result of
contact with a contaminated residential surface (e.g., hand or floor) can be defined as:
Csurfx - (CyXTE^KSA^) / (SAxy)] (12)
where
^surfx ~ surface loading (total or transferable) on x (ng/cm2)
x = hand, object, food item or anything else that enters the mouth
Cy = surface loading (total or transferable) on surface y (ug/cm2)
y = contaminated residential surface
TEy = transfer efficiency of contaminant from y to x (unitless)
SAxy = area of the object (x) contaminated as a result of contact with
contaminated surface (y) [cm2]
= area of the surface (y) contacted by the object (x) [cm2]
Note that the surface to object transfer efficiency (TEy) is a function of:
• Form of the pesticide (residue, particle bound, formulation, age, physicochemical
properties),
• Characteristics of surfaces (hard, plush, porous, loading, previous transfer),
• Characteristics of x (moisture, oil or fat content, age, loading, previous transfer),
• Contact mechanics (pressure, duration, smudge, repetition), and
• Environmental conditions (temperature, relative humidity, air exchange, redeposition
27
-------
rate).
Data Requirements for Microactivity Approach. To use the microactivity approach, a
significant level of detail is needed to characterize the potential for children's indirect ingestion
exposure to chemical residues and to quantify intake. Information and data required to estimate
indirect exposures include the following.
Common data needs for all events that lead to indirect ingestion exposure:
• Information on microenvironments/macroactivities that lead to indirect ingestion,
• Surface loadings in the important microenvironnients,
• Residue loadings on hands, if the child's hands are in contact with objects mouthed or
ingested, and
• Information on an individual child's hand washing practices.
Data needs for indirect ingestion exposure due to hand-to-mouth activities:
• Fraction of residue transferred from the hands to mouth during a mouthing event,
• Number of mouthing events in a 24-h period, and
• Surface area of hand contacted by the mouth.
Data needs for indirect ingestion exposure due to surface (including hand)- or object-to-mouth
activities:
• Information on what surfaces, body parts, toys, etc., are mouthed,
• Surface loadings for any objects or surfaces (including hands) mouthed by children,
• Transfer efficiency from the surface (including hands) to mouth during a mouthing event,
• Number of mouthing events during a 24-h period, and
• Surface area of object mouthed.
Data needs for indirect ingestion exposure due to consumption of handled food:
• Information on locations where an individual child consumes foods,
• Information on handled and consumed foods for an individual child,
• Area of surfaces and hands contacted by food,
• Transfer efficiency from surface or hand to food,
• Number and duration of food-to-hand and food-to-surface contact events, and
• Information on amount of specific foods that are consumed.
Macroactivity Approach. Because it would be too burdensome and costly to collect all
the data required to apply the microactivity approach for the time-sequence of events that occurs
on an individual basis, a macroactiviry approach is proposed here to provide a simplified
28
-------
assessment of indirect ingestion exposure to an individual based on measurement data collected
in the field. In this approach, objects (including hands and food) that are commonly handled,
mouthed, and/or ingested are identified in the field. The residue loadings on these objects are
measured directly or estimated from surface loading measurements combined with transfer
efficiencies measured in the laboratory. General information relating to the frequency and nature
of these mouthing and ingestion activities is also collected. Data on the fraction of residues that
may be removed from an object during mouthing that has been collected in the laboratory is then
required to complete the assessment. In this approach, only equations 10 and 11 are used.
Information on each of the individual contacts and transfer leading up to a surface loading on an
important item is lumped into the one loading measurement taken from that item. In addition,
the items identified as most often mouthed and/or eaten are assumed to represent the most
significant sources of indirect ingestion exposure. Note that a macroactivity approach analogous
to the one used for dermal exposure is not recommended here for indirect exposure. Currently, a
method for developing empirically derived transfer coefficients that lump mouthing contact,
surface area, and transfer for a series of mouthing events does not exist. No measure of indirect
ingestion exposure analogous to a dermal dosimeter exists. It is possible that in the future,
controlled studies could be conducted using a nontoxic tracer that could be tracked in biological
samples such as urine. Such a tracer would need to be applied as a surrogate for the
environmental contaminants of interest in a setting where children could interact with the items
of interest and exposures could be limited to indirect ingestion pathways. For now, we propose
an approach which attempts to directly link surface loadings and indirect ingestion activities to
provide a very basic screening assessment of indirect ingestion exposure.
Data Requirements for Macroactivity Approach. To use this macroactivity approach
to assess indirect ingestion exposure for an individual in a measurement study, information on
residue concentrations and factors characterizing general contact with items that are mouthed or
consumed is combined with transfer efficiencies that have been measured in the laboratory.
Research is continuing on the parameters that characterize the most common eating and
mouthing activities. The type of data that must be collected in the field include the following.
Data needs for indirect ingestion exposure due to hand-to-mouth activities:
• Residue loadings on the hands,
• General information on the frequency and nature (e.g., portion of hand that is mouthed) of
hand-to-mouth activity, and
• Information on an individual child's hand washing practices.
Data needs for indirect ingestion exposure due to surface- or object-to-mouth activities, other
than hands:
• Information on most commonly mouthed objects for an individual child,
• Surface residue loading measured from these objects, and
29
-------
• General information on the frequency and nature (e.g., portion of object that is mouthed)
of mouthing.
Data needs for indirect ingestion exposure due to consumption of handled food:
• Information on most commonly handled and consumed foods for an individual child,
• Information on contacts of foods with intermediate surfaces, including hands,
• Samples of these foods collected after handling, and
• General information on amount of these foods that are consumed.
30
-------
4.0 EXPOSURE SCENARIO
While many of the methods and approaches presented in this protocol should be generally
applicable or easily modified to address many children's exposure scenarios, this protocol
focuses on exposure of infants and young children to pesticides. The exposure scenarios used in
the development of this protocol are summarized in Table 4-1 and described below.
Table 4-1. Scenario for Protocol Development
Parameter
Pesticide Source
Exposure Population
Time Frame for Exposure
Microenvironments
Activities
Description
Any residential or daycare pesticide application
Children 4 years old or younger
Short-term, 1 to 7 days following application
Indoors at home, outdoors at home, indoors at daycare
centers, and outdoors at daycare centers
Active play, quiet play, sleeping, and eating
Sources. This protocol focuses on sources of pesticides in the residential and daycare
center environments. Indoor sources include: regularly scheduled professional crack and crevice
applications; general residential use of off-the-shelf formulations; and outdoor sources of turf and
garden pesticides. Following outdoor applications, exposure indoors may occur due to
infiltration of outdoor air into the residence or daycare or track-in of residues or particle-bound
pesticides.
For dietary exposures to occur, foods must contain pesticide residues, then the food must
be consumed. Many different sources can contribute to dietary residues and subsequent
exposure: foods containing pesticide residues are purchased from a commercial source and eaten;
foods containing residues are obtained from a noncommercial source (i.e., home gardens) and
eaten; and, foods from either commercial or noncommercial sources are obtained then
subsequently contaminated during transport, storage, or preparation. Lastly, foods from all
sources can be subsequently contaminated during consumption by a child (i.e., indirect ingestion
exposure).
Exposed population. The protocol describes the approaches for estimating the
exposures of children 4 years old or younger. Very young children may be particularly
31
-------
susceptible to pesticide exposures as the result of the microenvironments in which they spend
time (e.g., kitchen floor), and the activities in which they are involved (e.g., mouthing of hands
and toys and handling foods). It is important to understand that physiological characteristics and
behavioral patterns will result not only in different exposures for children and adults, but also for
children of different developmental stages. Thus, exposure assessments are required for children
in each age group, with age group being defined by developmental stage. Developing a
classification scheme for children by age group has been the subject of significant debate. The
Risk Assessment Forum (RAF) held a workshop on this topic hi July of 2000 (U.S. EPA, 2000b).
Some examples associated with relevant age-related developments for several exposure pathways
are presented hi Table 4-2. The age bins recommended by the RAF workshop for classifying
children based on behavior are presented in Table 4-3.
Table 4-2. Relevant Age-Related Developments (From U.S. EPA, 2000b)
Exposure Pathway
Breast Milk/Nursing
Bottle Feeding
Food
Water
Mouth-Hand Contact
Mouth-Object
Contact
Examples of Relevant Age-Related Developments
Nursing takes place roughly from 0 to 18 months of age, though this varies by
culture.
Bottle feeding takes place roughly from 0 to 12 or 24 months.
Head control (2 months), sitting (6 months), finger feeding (8 to 9 months),
use of utensils (10 to 12 months), and the final shift to adult patterns of eating.
Solid food, served in a bottle as a slurry, is often consumed as early as 1
month of age, but 4 to 6 months is the typical age range for beginning solid
foods by themselves.
Use of cups (6 to 9 months).
Prevalence of hand-to-mouth behaviors, such as thumb-sucking. Gross motor
skills determine access to areas where the hand can become contaminated.
Succession of gross motor milestones: rolling (4 months), creeping
(6 months), crawling (8 months), walking (12 months), and climbing
(18 months).
The ability to interact with objects is a major factor. The ability to grasp an
object to one's mouth begins roughly at 3 to 5 months. A pincer grasp and
moderate strength are achieved by 9 months. Children become aware that
objects exist even when covered around 6 months but generally do not
understand the meaning of the word "no" until 12 months.
32
-------
Table 4-3. Behavioral Age Bins (From U.S. EPA, 2000b).
Age Bin
0 to 2 months
3 to 5 months.
6 to 1 1 months
12 to 23
months
2 to 5 years
6 to 10 years
11 to 15 years
16 to 20 years
Characteristics Relevant to Oral and Dermal
Exposure
Breast and bottle feeding. Hand-to-mouth
activities. Rapid growth makes children
particularly vulnerable to chemicals.
Solid food is introduced. Contact with surfaces
increases. Object-to-mouth activities increase.
Food consumption expands. Children's floor
mobility increases. Children are increasingly
likely to mouth non-food items.
Children consume a full range of foods. They
participate in increased play activities, are
extremely curious, and exercise poor judgment.
Breast and bottle feeding cease.
Children begin wearing adult-style clothing.
Hand-to-mouth activities begin to approximate
adult patterns.
There is decreased oral contact with hands and
non-food items, as well as decreased dermal
contact with surfaces.
Smoking may begin. There is an increased rate
of food consumption.
High rate of food consumption continues.
Characteristics Relevant to
Inhalation Exposure
Children spend a great deal of
their time asleep.
Children may breathe close to
floor level when placed in play
pens or infant seats on the floor.
Development of personal dust
clouds.
Children walk upright, run, and
climb. They occupy a wider
variety of breathing zones and
engage in more vigorous
activities.
Occupancy of outdoor spaces
increases.
Children spend time in school
environments and begin playing
sports.
Increased independence. Work
outside of home begins.
Independent driving begins.
Expanded work opportunities.
Time frame of exposure. This protocol focuses on high-level, short-term (one to seven
days post-application) exposures resulting from recent pesticide applications. This time frame
may result in relatively high exposures. Because the explicit focus of this research is exposure
and not health risk, the relative health implications from a series of higher short-term exposures
versus lower chronic exposures were not considered although this is an important question
requiring a significant research effort. It is also assumed that for this time frame for indoor
applications, pesticides are primarily present in the form of residues, rather than being particle-
bound.
33
-------
Microenvironments of exposure. The protocol addresses data collection in residential
dwellings and daycare centers, which are considered the most important microenvironments for
the exposure of infants and very young children. Both the indoor and outdoor
microenvironments are considered.
Activities that result in exposure. Exposure associated with children's normal daily
activities are considered here. These include sleeping, quiet play, active play, and eating. The
activities most likely to result in significant exposures are likely to vary with the developmental
stage of the child. Activities specifically of interest for the ingestion pathways include all eating
and mouthing activities.
Assumptions. The most important assumptions made in applying this protocol for
assessing exposure for this scenario are as follows:
• The most significant concentrations of pesticide in this exposure time frame are present
as residues,
• The distribution of the pesticide residues on foods, objects, surfaces, and in the air in the
residential environment is not homogeneous,
• Measurement of residues on hands, objects, and foods collected at specific time points
can be used to estimate ingestion exposures over the time frame of interest, and
• In the time frame of concern for this scenario (short-term following an application),
exposure resulting from ingestion of soil and house dust is less important than indirect
ingestion of residues.
For dietary exposure, transport, storage, preparation, and consumption may have an affect
on the pesticide levels in the foods. All but the consumption aspects of these activities are taken
into consideration when duplicate diet samples are collected. The most important assumptions
made for assessing dietary exposure by the duplicate diet methods are as follows:
• Sample collected represents the foods consumed by the child,
• The portion sizes are adjusted for actual amounts of foods eaten,
• The variability in pesticide levels in the foods collected and those eaten is very small, and
• Exposures are only representative of those incurred during the monitoring period.
34
-------
5.0 APPROACH FOR ESTIMATING INHALATION EXPOSURE
5.1 Introduction
Inhalation is a potentially important route of exposure to pesticides for children in
residences, daycares, schools, and other microenvironments. Inhalation exposure depends on
many factors including the physical characteristics of the pesticides (e.g., vapor pressure),
formulation, application method (e.g., crack and crevice application versus room fogger),
location of application (e.g., indoors, outdoors, basement, living areas), and factors related to the
macroenvironment (e.g., air exchange rate of the building, mixing between rooms, indoor
temperature). Inhalation exposure may be more significant for very young children than for older
children or adults. Infants and young children have a higher resting metabolic rate and rate of
oxygen consumption per unit body weight than adults. They may also spend more time indoors
and in closer proximity to pesticide sources (e.g., while playing or sitting on the floor). Young
children who spend substantial amounts of time in residences may also have potentially higher
inhalation exposure than children in daycares or schools due to lower air exchange rates in homes
than in commercial buildings. However, the latter types of buildings may have higher pesticide
usage than residences.
Inhalation exposure has been estimated for a wide range of volatile and semi-volatile
organic compounds, including pesticides. There have been a number of studies involving
measurements of pesticides in air (e.g., Lewis, et al, 1994; Whitmore et al., 1994; Gordon et al.,
1999; Quackenboss et al., 2000). Much of the prior data on indoor air concentrations are for
concentrations of organophosphorous, organochlorine, and other pesticides that are not currently
used indoors. There are few data available on pesticides currently used indoors, such as the
pyrethroids. Of all the potential routes of exposure to pesticides, inhalation has been studied the
most. The protocols and methods for measurements of pesticides in air are the most well-
developed of the aggregate exposure measurement methods.
5.2 Summary of Data Requirements
As described in Section 3.2, inhalation exposure is estimated for each of the
microenvironments where a child spends time and for each macroactivity that would result in a
different inhalation rate while engaged in that activity. Exposure over the 24-hour period is then
the sum of all of the microenvironmental/macroactivity (me/ma) exposures.
The data required to estimate inhalation exposure are summarized in Table 5-1.
5.3 General Considerations
To estimate inhalation exposure for young children, it is necessary to use stationary
samplers in selected microenvironments to collect air samples for pesticide analyses. Although
35
-------
Table 5-1. Data Requirements for Estimating Inhalation Exposure Route
Parameter
Measurement
How Collected
Units
Inhalation Exposure
F =C x T v TR
*-'ime/ma vxame "• x me/ma "• " Tna
Came
T
A me/ma
IRm
Air concentration in me
Time spent in each
me/ma
Inhalation rate
Active sorbent collection
Time-activity diary,
questionnaire
Estimated from size, age, and
activity data collected with
diaries and questionnaires and
using reference values
Hg/m3
h/d
m3/h
a preferred method for measuring an individual's exposure to air contaminants is to have the
study participant wear a personal exposure monitor (PEM), this method is not suitable for young
children less than 4 years old. Because it is not possible to measure the air concentrations in all
microenvironments that a child may occupy, it is important to identify which microenvironments
represent the highest potential exposures based on the amount of time spent in each micro-
environment. For children age 0 through 4 years, the important microenvironments include the
residence and daycares. For infants, measurement of air concentrations in the home, preferably
in the room where the infant spends the most time during the day, will be representative.
Because of the small amount of time spent outdoors and the low outdoor concentrations relative
to indoor concentrations after pesticide applications, it may not be necessary to measure outdoor
air concentrations to estimate an infant's inhalation exposure. As children age and spend more
time outdoors, it becomes important to measure outdoor air concentrations, although the levels
may be very low for most pesticides.
Microenvironment/macroactivity data need to be collected to identify all of the important
microenvironments that a child may occupy. If there are important microenvironments other
than the residence and daycare, it is necessary to estimate air concentrations in those micro-
environments. To make these estimates, it is generally necessary to assume that there have been
no recent applications of the pesticides of concern in that microenvironment and a reasonable
concentration must be used for the exposure estimate. This reasonable concentration would be
the background concentrations measured outdoors or in indoor microenvironments without
recent applications of the target pesticide.
Measurements of indoor air concentrations of pesticides require active pumping systems
to collect air samples on sorbent media. Placement of the sampling equipment indoors presents a
36
-------
variety of sampling challenges because of presence of the occupants, including small children,
and the restricted space hi indoor environments. Because air monitoring is often intrusive, it is
particularly important that field personnel be sensitive to the burden placed on study participants.
Pump noise is a critical concern when sampling indoors, particularly in sleeping areas. Low-
noise pumps must be used indoors. Noise may be minimized by placing pumps hi a small ice
chests or metal boxes containing sufficient acoustic insulation to baffle the sound of pump
motors. Pumps may be located in closets or behind furnishings to further minimize noise and
remove the apparatus from traffic zones.
Because the sampling equipment is left unattended at the sampling site, field teams must
consider both the safety of the children in the location where sampling is performed and the
potential for tampering with instrumentation or theft (outdoors). Extreme care must be taken so
that the pumps, sampling trains, and sorbent tubes pose no safety concerns. Samplers can not be
accessible to children or placed on stands that can be tipped over. There should be no small parts
that could be removed by children that could cause potential choking hazards. If glass sampling
cartridges are used, they must be protected with unbreakable shields that prevent breakage or that
will contain all media if breakage occurs. Pumps and sampling cartridges should be place out of
the reach of small children. Appropriate security measures include placing pumps hi locked
boxes, tamper proof shielding over the pump controls, and the placement of sampling apparatus
out of the reach of small children and pets.
Power sources may be unstable hi some locations and may produce disruptions during
monitoring activities. When possible, battery back-up or an un-interruptible power source should
be used to decrease the impact of these occurrences on sample collection.
Selection of sampling locations within a room is important to obtain representative air
concentrations. As discussed in the following section, samplers should be placed at an
appropriate height and location in the room. They should not be placed near windows, air supply
diffusers or returns, or other locations where the air flow may affect air concentrations.
5.4 Monitoring and Sampling Methods
Measurements of pesticides in air for estimates of young children's inhalation exposure
require collection of air samples with active sampling systems consisting of sorbent media and
vacuum pumps. Concentrations of pesticides hi air are obtained by collection of integrated air
samples on the sorbent media, extraction of the sampling media, and analysis by an appropriate
method, generally gas chromatography (GC) or high performance liquid chromatography
(HPLC).
Pesticides are semi-volatile compounds with saturation vapor pressures of less than 10"2
kPa. Many of the synthetic pyrethroids (e.g., cyfluthrin, cypermethrin, esfenvalerate) that are
currently used for indoor applications, have saturation vapor pressures of less than 10"8 kPa As a
37
-------
result, the air concentrations of these compounds are generally low and decrease rapidly
following an application (Lewis et. al., 2001). Sampling and analysis methods for the current
generation of pesticides applied indoors must address the low volatility and potentially low
concentrations. The methods must have sufficiently low detection limits and good performance
characteristics at low levels. As an example, the median concentrations of chlorpyrifos and
diazinon, which are relatively volatile compounds compared to pyrethroids and other current use
pesticides, were 8.0 and 4.6 ng/m3' respectively, in the Arizona NHEXAS samples (Gordon et al.,
1999).
The collection of airborne pesticide residues on sorbent media is generally performed
using commercially available small, portable, low volume pumps that can be operated over a
range of flow rates of 0.1 to 4 L/min. The pumps, which can be operated on batteries or with AC
power, must be sufficiently quiet for use in occupied environments and suitable for collection of
integrated samples over a 24 hour period. It should be noted that these monitoring pumps as
purchased are typically powered by rechargeable NiCad battery packs and are generally designed
for 8 to 16 hour occupational exposure monitoring. These pumps may not have sufficient battery
life for a 24 hour monitoring, but can usually be modified by a qualified electronics technician or
by the manufacturer to operate using disposable alkaline batteries to provide adequate run times.
Such modifications will generally void warranties and void the intrinsic safety of the pump for
use in hazardous locations. Operation of the pumps on AC power circumvents the need to
modify the pumps but lack of easily accessible power outlets may add significant set-up time,
create safety hazards by requiring the use of extension cords, or force the collection of samples in
less desirable locations due to the difficulties of having to supply AC power. Pump failures may
also be caused by unstable or interrupted AC power. If rechargeable batteries are used, care must
be taken to insure that the batteries are discharged and charged properly to minimize failure due
to charge memory effects. Likewise, if alkaline batteries are used, voltages of the batteries
(especially partially used batteries) should be determined prior to beginning sample collection to
insure that the batteries will provide sufficient power to operate the pumps for the desired time
period.
Flow rates of sampling pumps are set to obtain a specified volume based on the duration
of the monitoring period, retention efficiency of the target pesticides on the sorbent, and the
sensitivity of the analytical method. High volume pumps are not appropriate for sampling
indoors because of considerations of noise and the impact that collection of high air volumes
indoors may have on air exchange rates and air movement in the rooms. High volume pumps
may be used outdoors.
A variety of sampling media are available for collection of pesticides in air. Available
sorbents include polyurethane foam (PUF), Amberlite® XAD-2, Amberlite® XAD-4,
Chromosorb® 102, Tenax® GC or TA, and Porapak®-R. These absorbents have similar
efficiencies for collection of most pesticides (Lewis, 2000). PUF has been used as the sorbent
media in a number of field measurement studies (e.g., Whitmore et al., 1994; Gordon et al.,
38
-------
1999) and its use is described in an ASTM standard practice (ASTM, 2000a). XAD resin has
been used extensively for collection of semi-volatile organic compounds (U.S. EPA, 1999b) and
can be used as an alternative to PUF.
Sorbent media may be used individually or in multi-bed combinations. The sample
media may be constructed in series to collect both gas phase residues as well as levels of airborne
particles. The sampler may consist of a combination of particle sizing devices (to collect only
inhalable or respirable particles below 10 or 2.5 urn diameter), membrane filters to collect
particles, sorbent resins, and/or polyurethane foam. Selection of the sampling media should be
based on the physio-chemical characteristics of the compound(s) of interest, sampling efficiency,
retention efficiency, performance characteristics based on available literature or laboratory
validation studies for all analytes of interest, cost, and ease of use.
The selection of the multi-residue sampling and analysis methods should consider the
following factors:
• The suite of pesticides to be targeted for quantification and their physical and chemical
properties,
• Range of air concentrations expected,
• Minimum detection and quantification limits required,
• Availability of validated methods for the pesticides of interest,
• Available performance data (accuracy, precision, detection limits) for the method,
• Required sampling volumes and sampling duration.
Information that can be used to select sampling and analysis methods is available in the
scientific literature, ASTM (2000a), and in U.S. EPA (1999b) methods. Information on pesticide
sampling methods for measurements in occupational settings is available in publications by
NIOSH (1994), OSHA (2000), and manufacturers of samplers and sorbent media. However,
researchers conducting exposure measurements in residential and daycare environments should
recognize that the methods developed to measure occupational exposure may not be sufficiently
sensitive to measure the lower concentrations often encountered in non-occupational
environments.
The performance of the sampling and analysis method needs to be fully evaluated prior to
use in field studies. As discussed previously, method detection limits must be sufficiently low
for measurements in residences and daycares. Typically, detection limits for analysis of
pesticides by GC/MS can be expected to be in the range of 5 to 50 ng/m3, which varies by
compound and sample collection volume. Precision should be ± 25% and the accuracy,
expressed as the percent recovery of spiked samples, should be in the range of 75 to 125%.
Users of the methods also need to determine the sampling and retention efficiency of the sorbent
media for the target pesticides. Sampling efficiency is the ability of the sampling medium to trap
the pesticides of interest (ASTM, 2000a). Retention efficiency is the ability of the sampling
39
-------
medium to retain the compound of interest. Methods for determining sampling and retention
efficiencies are described in ASTM practice D4861 (ASTM, 2000a). This practice lists sampling
and retention efficiencies for a number of organochlorine and organophosphorous pesticides and
for a few pyrethroids collected on PUF. However, there are limited data on performance
characteristics for many of the pyrethroids.
The selection of the indoor sampling locations is contingent on the study objectives.
Measurements of pesticide concentrations in the rooms where pesticide applications have been
performed recently may provide an estimate of the highest potential exposure. But,
measurements in locations where children spend the majority of their time may provide more
accurate exposure estimates. The concentrations of pesticides in the air of a residence or daycare
may vary substantially in different parts of the building following pesticide applications. Lewis
et al. (2001) observed concentrations of diazinon in a bedroom that were less than one-third the
concentrations measured in the room of application on the day following application. The
difference between the rooms was even greater on the following days. Spatial differences may
require measurements in more than one location in a residence or daycare to obtain accurate
estimates of inhalation exposure. This may be cost prohibitive in large field studies. Therefore,
emphasis should be placed on identifying the location where the child has the highest potential
for exposure due to proximity to a source, activities (crawling, playing with pet, eating, etc.) or
time spent in a location (i.e. living room, play ground, bedroom etc.). Outdoor sampling
locations should be selected that are representative of the areas where the child spends time
outdoors. Samplers should not be placed immediately adjacent to buildings where pesticides
may be used or stored.
5.5 Exposure Factor/Activity Pattern Information
To estimate inhalation exposure, information must be collected to describe the (1) child,
(2) microenvironments occupied by the child, and (3) the child's activity while in those
microenvironments.
The minimum information required to characterize the child is the child's age, weight,
and gender. These variables are used to estimate inhalation rates.
Information on the child's location (microenvironment) and activity need to be recorded
throughout the measurement period. For individual measurement assessments, the total time
spent at each level of activity in each microenvironment must be recorded. For studies currently
being performed in the NERL Human Exposure Analysis Branch, four microenvironments have
been defined: indoors at home, outdoors at home, indoors at daycare centers, and outdoors at
daycare centers. These four microenvironments are assumed to provide a reasonable estimate for
inhalation exposure for young children (under age 4). Four macroactivities have been defined for
this age group: active play, quiet play, sleeping/napping, and eating. An activity diary (Figure 5-
1) is used for recording the activities in these microenvironment/macroactivity combinations.
40
-------
Figure 5-1. Example of one page of the Indoors at Home section of a 24-h time-activity diary for estimating inhalation and dermal
exposure of young children
3
,lj
Microenv
§
ffi
3
52
o
o
a
"u
1
IP
£
o
O
£•
>
1
1
Active Play
Quiet Play
Eating
Sleeping/
Napping
^M
Hard Surface
Carpet
Upholstered
furniture/
Bedding
Hard Surface
Carpet
Upholstered
furniture/
Bedding
Hard Surface
Carpet
Upholstered
furniture/
Bedding
Hard Surface
Carpet
Upholstered
furniture/
Bedding
o
o
\o
v>
VO
O
w
o
Vl
•*•
VO
0
o
r~
VI
r~
o
CO
r~
>n
>^-
r~
I
oo
>o
oo
o
f>
oo
m
•«*
oo
o
o
0\
<0
o
o
f>
Os
IT)
TT
O
O
O
o
v>
o
o
m
o
V~l
•
rj-
1
O
O
1LS=long-sleeves; SS=short-sleeves; P=pants; S=socks; SH=shorts; N=naked
-------
The diary also collects information on clothing level and the type of surface in the
microenvironment, information needed for dermal exposure estimates. The diary includes
multiple pages, one each for indoors at home, outdoors at home, indoors at daycare, and outdoors
at daycare and covers a 24-h monitoring period. Activities must be recorded by the parent or
caregiver of the child. For the most accurate data collection, activity should be recorded on a
continuous basis during the 24-hour measurement period. However, data collection by recall
may be suitable if the parent or caregiver is provided with adequate instructions at the start of the
measurement period and is aware of the need to record the data at a later period. Recall periods
should be kept relatively short, generally no longer than 24 hours. Although, parents and
caregivers can provide reasonably accurate data on the location of the
child in the four microenvironments, they may have difficulty defining active versus quiet play.
Therefore, it is important to provide training to the parent or caregiver on how to determine what
to record for the child's activity. To improve estimates of inhalation rates, researchers may want
to define additional levels of activity. However, if additional levels of activity are defined,
additional training of the parent or caregiver will be required. A videotape of children's different
activity levels may be used for that purpose.
5.6 Estimation of Inhalation Rates
Inhalation rates for children are highly variable and are a function of the child's age,
weight, and activity. The actual inhalation rates are not routinely measured in individual
measurement studies. As an alternative, information on the child's activities is collected during
field measurement studies and used to estimate inhalation rates.
Ranges of inhalation rates for children developed by NERL (McCurdy, 2001) using
available measurement data are presented in Tables 5-2 and 5-3. The data presented in the tables
should be used to calculate inhalation rates based on children's age and weight. Data used to
compile the ranges of inhalation rates shown in the tables are the same as those used by the EPA
in the Exposure Factors Handbook (U.S. EPA, 1997a) and the Child-Specific Exposure Factors
Handbook (U.S. EPA 2000c).
Inhalation rates for short-term exposures of children under age 18 are presented in the
Child-Specific Exposure Factors Handbook. But they are based only on the activity levels and
do not account for the child's age or weight. The recommended rates from the handbook for
children 18 years of age and under are:
Rest: 0.3 m3/h,
• Sedentary Activities: 0.4 m3 /h,
• Light Activities: 1.0m 3/h,
• Moderate Activities: 1.2 m3 /h, and
• Heavy Activities: 1.9 m3 /h
42
-------
Table 5-2. Ranges of Inhalation Rates (VE) for "Normal" Female Children and Adolescents on a
per Body Mass Basis by Generalized Type of Activity (L min'1 kg'1)
Age
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
Sleep/Nap
/Rest
0.17-
0.16-
0.15-
0.14-
0.14-
0.13-
0.12-
0.11-
0.10-
0.10-
0.09-
0.09-
0.08-
0.08-
0.08-
0.07-
0.07-
0.06-
0.20
0.19
0.18
0.17
0.16
0.15
0.14
0.13
0.12
0.12
0.11
0.10
0.10
0.09
0.09
0.08
0.08
0.07
Sedentary/
Sitting Quietly
0.21
0.20
0.19
0.18
0.17
0.16
0.15
0.14
0.13
0.13
0.12
0.11
0.11
0.10
0.10
0.09
0.09
0.08
-0.26
-0.25
-0.23
-0.22
-0.21
-0.20
-0.18
-0.17
-0.16
-0.15
-0.14
-0.13
-0.13
-0.12
-0.11
-0.10
-0.10
-0.09
Light Activity
/Walking
0.27
0.26
0.24
0.23
0.22
0.21
0.19
0.18
0.17
0.16
0.15
0.14
0.14
0.13
0.12
0.11
0.11
0.10
-0.69
-0.68
-0.67
-0.66
-0.65
-0.64
-0.63
-0.60
-0.59
-0.57
-0.53
-0.50
-0.49
-0.48
-0.47
-0.44
-0.43
-0.42
Moderate
Activity
/Jogging
0.70-
0.69-
0.68-
0.67-
0.66-
0.65-
0.64-
0.61-
0.60-
0.58-
0.54-
0.51-
0.50-
0.49-
0.48-
0.45-
0.44-
0.43-
1.05
1.04
1.03
1.02
1.01
1.00
0.96
0.93
0.92
0.91
0.87
0.83
0.80
0.78
0.76
0.73
0.71
0.69
Vigorous
Activity/
Running
1.06-
1.05-
1.04-
1.03-
1.02-
1.01-
0.97-
0.94-
0.93-
0.92-
0.88-
0.84-
0.81-
0.79-
0.77-
0.74-
0.72-
0.70-
1.25
1.26
1.27
1.28
1.29
1.30
1.32
1.33
1.34
1.36
1.35
1.35
1.36
1.37
1.38
1.38
1.38
1.38
Notes: 1. These data should only be used for "normal" children and adolescents. Different estimates are
needed for obese, underweight/sickly kids, as well as children/adolescents who are very fit due to
partaking in frequent and "heavy" exercise.
2. To obtain activity-specific VE (in L), simply multiply the estimate shown above by time spent in
each category (in minutes) and also by body weight (in kg) of the child/adolescent in question. These
values can then be converted into m3 per whatever time period is of interest by multiplying
by the appropriate unit conversions.
3. The values shown have been "smoothed" to minimize abrupt jumps by age. The data within a range
for each activity level probably are distributed log-normally, but definitive information on this
distribution is scanty. The upper bound of the "Vigorous" class is the same as VEMax, and it cannot be
maintained more than approximately 5 minutes before it declines over time; see Bink (1962) and Erb
(1981).
Sources: U.S. EPA (2000c), U.S. EPA (1997a), and McCurdy (2001)
43
-------
Table 5-3. Ranges of Inhalation Rates (VE) for "Normal" Male Children and Adolescents on a
per Body Mass Basis by Generalized Type of Activity (L min'1 kg'1 )
Age
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
Sleep/Nap
/Rest
0.18
0.17
0.16
0.15
0.14
0.14
0.13
0.12
0.11
0.11
0.10
0.09
0.09
0.09
0.08
0.07
0.07
0.07
-0.21
-0.20
-0.19
-0.18
-0.17
-0.16
-0.15
-0.14
-0.13
-0.13
-0.12
-0.11
-0.10
-0.10
-0.09
-0.08
-0.08
-0.08
Sedentary Light Activity
/Sitting Quietly /Walking
0.22-
0.21-
0.20-
0.19-
0.18-
0.17-
0.16-
0.15-
0.14-
0.14-
0.13-
0.12-
0.11-
0.11-
0.10-
0.09-
0.09-
0.09-
0.27
0.26
0.24
0.23
0.21
0.20
0.19
0.17
0.16
0.15
0.15
0.13
0.12
0.12
0.11
0.10
0.10
0.09
0.28
0.27
0.25
0.24
0.22
0.21
0.20
0.18
0.17
0.16
0.16
0.14
0.13
0.13
0.12
0.11
0.11
0.10
-0.74
-0.74
-0.73
-0.72
-0.71
-0.70
-0.69
-0.64
-0.64
-0.63
-0.59
-0.57
-0.56
-0.55
-0.53
-0.52
-0.51
-0.51
Moderate
Activity
/Jogging
0.75
0.75
0.74
0.73
0.72
0.71
0.70
0.65
0.65
0.64
0.60
0.58
0.57
0.56
0.54
0.53
0.52
0.52
-1.13
-1.13
-1.12
-1.12
-1.11
-1.10
-1.05
-1.04
-1.03
-1.00
-0.95
-0.94
-0.93
-0.90
-0.89
-0.88
-0.87
-0.86
Vigorous
Activity
/Running
1.14-
1.05-
1.04-
1.13-
1.12-
1.11-
1.06-
1.05-
1.04-
1.01-
0.96-
0.95-
0.94-
0.91-
0.90-
0.89-
0.88-
0.87-
1.76
1.77
1.78
1.79
1.80
1.81
1.83
1.77
1.72
1.64
1.59
1.56
1.50
1.47
1.44
1.42
1.39
1.38
Notes: 1. These data should only be used for "normal" children and adolescents. Different estimates are
needed for obese, underweight/sickly kids, as well as children/adolescents who are very fit due
to partaking in frequent and "heavy" exercise.
2. To obtain activity-specific VE (in L), simply multiply the estimate shown above by time spent in
each category (in minutes) and also by body weight (in kg) of the child/adolescent in question. These
values can then be converted into m3 per whatever time period is of interest by multiplying
by the appropriate unit conversions.
3. The values shown have been "smoothed" to minimize abrupt jumps by age. The data within a range for
each activity level probably are distributed log-normally, but definitive information on this distribution
is scant. The upper bound of the "Vigorous" class is the same as VEMax, and it cannot be
maintained more than approximately 5 minutes before it declines over time; see Bink (1962) and
Erb(1981).
Sources: U.S. EPA (2000c), U.S. EPA (1997a), and McCurdy (2001)
44
-------
These inhalation rates are within the range of rates presented in Tables 5-2 and 5-3. But more
accurate estimates of inhalation exposure can be made using the range of rates presented hi the
tables for calculations based on the child's age and weight.
45
-------
6.0 MACROACTIVITY APPROACH FOR ESTIMATING DERMAL EXPOSURE
6.1 Introduction
Data on children's exposures and activities are currently very limited and insufficient to
support quantitative assessments that do not rely heavily on major default assumptions. Results
derived from an initial assessment of critical exposure pathways and factors for assessing
children's residential exposures to pesticides indicate that dermal exposure and indirect
nondietary ingestion exposure may result in high residential exposures for children (Cohen Hubal
et al. 2000).
Two main approaches are currently used to assess dermal exposure. These assessment
approaches provide different ways of integrating exposure over time and space. In the
macroactivity approach, exposure is estimated individually for each of the microenvironments
where a child spends time and each macroactivity that the child conducts within that
microenvironment. To do this, exposure is modeled using empirically derived transfer
coefficients to aggregate the mass transfer associated with a series of contacts with a
contaminated medium. In the microactivity approach, exposure is explicitly modeled as a series
of discrete transfers resulting from each contact with a contaminated medium. The algorithm and
data requirements for the microactivity approach were described briefly in Section 3.3.2.
However, as discussed in that section, implementation of the microactivity approach is not
practical in large exposure field studies. Therefore, details of the approach are not discussed in
this protocol. This section describes the macroactivity approach for estimating dermal exposure.
6.2 Summary of Data Requirements
To estimate exposure using the macroactivity approach, microenvironments are defined
by location and surface type. Activity- and microenvironment- specific transfer coefficients are
developed in laboratory experiments or controlled field studies. Exposure can then be estimated
individually for each of the microenvironments where a child spends time and each macroactivity
that the child conducts within that microenvironment using information on surface loadings, the
empirically-derived transfer coefficients, and information on the amount of time in that
microenvironment/macroactivity. The dermal exposure algorithm and data requirements are
presented in Table 6-1.
6.3 General Considerations
Numerous data must be considered for each microenvironment/macroactivity
combination when estimating dermal exposure. These data include: definitions of the
microenvironments/macroactivities that are important for dermal exposure; surface loadings
(total or transferable) of pesticides or chemicals for each microenvironment/macroactivity
combination; amount of time a child spends in each microenvironment/macroactivity during a
46
-------
Table 6-1. Data Requirements for Estimating Dermal Exposure With the Macroactivity
Approach
Parameter
Measurement
How Collected
Units
Dermal Exposure - Macroactivity approach
^dme/ma ~~ (^surfX * ^me/ma)(AU 'me/ma)
Csurf
TC
1 ^me/ma
•A~Dme/ma
Surface loading (total or
transferable) in the me
Transfer coefficient
Exposure duration based on
location, activity level,
clothing
Measure with Clg surface press
sampler, PUF roller, surface
wipe, or soil sample
Empirically determined for
each me/ma from laboratory or
field studies
Time-activity diary,
questionnaire
ug/cm2
cm2/h
h/d
24-h period; and, the transfer coefficient for each microenvironment/macroactivity. These data
considerations affect the subsequent sampling considerations. Each consideration is discussed
more fully in the following paragraphs. Table 6-2 lists the various microenvironment
/macroactivity combinations that are applicable to the exposure scenario described in Section 4.
For each microenvironment/macroactivity combination, the surface loading of the
chemical must be determined. For recent pesticide applications, the assumption, based on
limited field data, is that the pesticide surface loading is not homogeneous in the residential or
daycare center environment, hi order for the measurements that are collected to be most
applicable and representative of the child's environment, it is important to determine those
locations where the child spends the most time in the residential or daycare center environment
and sample accordingly. For each home or daycare center, measurements will be made for only
those surfaces for which the child is expected to have substantial contact. This sample
measurement can be collected using the C]g surface press sampler, a PUF roller, surface wipe, or
for outdoor locations to collect a soil or turf sample.
For each microenvironment/macroactivity combination, the amount of time the child
spends in each combination must be determined. These data are collected using time-activity
diaries or questionnaires.
47
-------
Table 6-2. Microenvironment/Macroactivity Combinations for Estimating Dermal Exposure
Location
Indoor at home
Outdoor at home
Indoor at daycare
Outdoor at daycare
Surface
Carpet
Hard surface
Upholstered
furniture/bedding
Grass
Soil
Pavement
Carpet
Hard surface
Upholstered
furniture/bedding
Grass
Soil
Pavement
Activity
Eating
X
X
X
X
X
X
X
X
X
X
X
X
Sleeping/
napping
X
X
X
X
X
X
X
X
Quiet play
X
X
X
X
X
X
X
X
X
X
X
X
Active play
X
X
X
X
X
X
X
X
X
X
X
X
The transfer coefficients for each microenvironment/macroactivity must also be
determined. These are data that are currently not available and need to be generated
experimentally in the laboratory or carefully controlled field experiments. This is discussed more
fully in Section 6.6, Estimation of Transfer Coefficients.
Environmental monitoring methods for assessing dermal exposure have few equipment
considerations, as compared to the inhalation route. However, the concentrations associated with
each sample are dependent on the locations sampled and the sampling method used. Pesticide
distributions in the residential environment are not homogeneous which may result in significant
concentration differences in adjacently sampled areas potentially leading to an over or
underestimation of exposures depending on the representativeness of the sampling locations. For
this reason, the appropriate sampling locations, sampling methods that address various surface
48
-------
types, and the number of samples required to provide representative information must all be
considered. Outlined below are issues that should be considered when assessing the dermal
route of exposure as a component of a large field study:
• Surface sampling methods should be matched to the sampling method that was used to
generate the transfer coefficients. For example, transferable residue measurements should
be collected using a Clg surface press sampler method if the C18 surface press sampler
method was used to generate the transfer coefficient.
• Methods of collection should be appropriate for the types of surfaces being monitored.
For example, surface wipe samples should be collected from hard surfaces and not from
carpets or other fabric surfaces.
• When possible, multiple individual samples (at least three) should be collected from
various areas in the microenvironment where the child is in contact with surfaces.
Analyzed individually, these samples will provide information regarding the distribution
of pesticides in the microenvironment; when the results are combined, they provide an
average value to help minimize under or overestimation of surface loadings, and thus,
exposure.
• Locations for monitoring and sample collection should be selected that are representative
of where the child spends his/her time. Locations targeted for monitoring should be
consistent with the study objective. Avoid monitoring locations that may bias the results
such as pouits of application or near sources of potential contamination unless they are
part of the study design.
• To reduce analytical costs, it may be possible to collect aggregate samples (e.g., surface
press), or combine samples (e.g., surface wipes) prior to analysis to obtain "average"
concentrations.
• Be cognizant of the potential damage that sampling methods may pose to personal
property. For example, isopropanol used during the collection of surface wipe samples
can cause damage to wood finishes or other sensitive surfaces; therefore, samples should
not be collected from surfaces that would be damaged by the collection method.
6.4 Monitoring Methods
As discussed above in General Considerations, the loadings of pesticides on surfaces
associated with each of the microenvironment/macroactivity combinations that a child conies
into contact with are essential data for estimating dermal exposure. However, since it is
impossible to measure the pesticide loadings for all surfaces in all situations, surface loadings are
measured for only those areas for which children are expected to have substantial dermal contact.
It is extremely important that the surfaces that are sampled are representative of the surfaces for
which the child may have appreciable contact during his/her various activities. These areas would
include indoor surfaces, either at home or in a daycare center, such as floors and furniture, as
well as outdoor surfaces such as grass, soil, and pavement. Floors include both carpeted areas
and hard surface areas such as vinyl, tile, or wood. Furniture can be categorized as upholstered
49
-------
(fabric) or hard (metal, vinyl, wood) surfaces. These previously mentioned microenvironment
locations are specific to the exposure scenario as defined in Section 4. It should be recognize
that other locations may be of equal, or greater importance for other exposure scenarios. For
example, the interior of motor vehicles may be an important microenvironment in agricultural
areas due to spray drift from pesticide applications on crops. Exposure to pesticides bound to
settled dust on the seats or other interior surfaces of a vehicle may be a source of exposure.
Measurements to determine surface loadings can be divided into two categories: those
representing the total amount of pesticide residue present on a surface and those representing the
amount of pesticide residue that is available for transfer (i.e., transferable residues). Methods for
estimating total pesticide residues include the collection, extraction, and analysis of upholstery
fabrics, carpet, and soil samples. Transferable residues can be estimated by collecting and
analyzing surface wipe, surface press or roller samples. These latter methods provide an
estimate of the amount of each pesticide that is available for transfer from one surface to another.
The methods used must be appropriate to the type of surface to be sampled.
The transferable residue measurement methods do not necessarily simulate the contact
that a child may make with the surface being sampled and should not be considered surrogate
exposure methods. It is not feasible to simulate all of the skin surfaces of a child that may
contact surfaces in the microenvironment. A child may contact a surface with the feet, knees,
legs, bottom, arms, hands, or face. Skin surfaces may be dry, wet, or sticky. Rather than
attempting to simulate these skin surfaces, the approach has been to use a method to measure
transferable residues on the surfaces in conjunction with transfer coefficients to estimate dermal
exposure. As discussed previously, the transfer coefficients must be developed in laboratory
tests or under carefully controlled field experiments. The transfer coefficients must be developed
using the same method for measuring surface loading as is used in the field measurement studies.
Transfer coefficients can be developed for a wide variety of microenvironment/macroactivity
combinations, hard and soft surfaces, as well as dry, wet, and/or sticky skin.
Brief descriptions of some of the more common methods developed for estimating total
and transferable pesticide residues are discussed below.
PUF Roller. The PUF roller method is designed to estimate transferable residues from
carpeted or hard flooring surfaces (Camann et al., 1996). It has also been used to measure
transferable residues from outdoor surfaces such as turf (Nishioka, et al., 1999). It is described in
ASTM Standard Practice D6333 (ASTM 2000b) and consists of a polyurethane foam sleeve
roller attached to an aluminum frame of specified dimensions and weight. The foam sleeve is
rolled across a specified area of the surface being monitored at a specified pressure (6900 to 8600
Pa). The foam sleeve is removed, solvent extracted and analyzed for pesticides by GC/MS,
GC/ECD, or other suitable instrumental method.
Drag Sled. The Drag Sled sampler is designed to estimate transferable residues from
50
-------
floor surfaces (Vaccaro and Cranston, 1990). The sampler consists of a 7.6 cm x 7.6 cm x 1.9
cm block of wood or other material that holds a 10 cm x 10 cm piece of denim cloth as the
sampling media. With the denim cloth in contact with the flooring surface, a weight is applied to
the block to provide a specified pressure (4500 Pa). The device is pulled at a specified rate
across the floor area. The denim cloth is removed, extracted, and analyzed for pesticides by
GC/MS, GC/ECD, or other suitable instrumental method. This method has not been used
extensively.
California Roller. The California Roller, described by Ross et al. (1991), is designed to
estimate transferable residues from indoor and outdoor surfaces. The sampler consists of a large
weighted roller that uses polyester-cotton percale bedding material as the sampling media. The
roller is a large cylinder (13 cm OD, 63 cm in length) constructed of polyvinyl chloride pipe,
partially filled with steel shot to provide a specified pressure (2300 Pa), and is covered with a 1
inch foam cushion. The polyester-cotton percale material is placed directly in contact with the
flooring surface to be sampled, a sheet of plastic is placed on top of the cloth and the roller is
rolled over the plastic/cloth. The cloth is solvent extracted and analyzed for pesticides by
GC/MS, GC/ECD, or other suitable instrumental method. The original method has been
modified and its performance has been compared to other methods (Fortune, 1997). The method
has been used most extensively by pesticide registrants.
Surface Press or Mechanical Press. The surface press or mechanical press method is used
to estimate transferable residues from hard and soft surfaces. Currently, a sampler based on the
design of the EL press sampler (Edwards and Lioy, 1999) is being evaluated in pilot studies by
NERL. In general, this method consists of a block shaped device constructed of Delrin polymer
and uses C,8 impregnated Teflon extraction disks (3M Empore® disks) as the sample collection
media. Other collection media are being considered but have not been fully evaluated at this
time. The surface press sampler holds two C,g disks while providing a specific contact area (114
cm2) and contact pressure (-1200 Pa). Once the disks are loaded into the sampler the sampler is
placed on the surface to be monitored and allowed to remain in contact for a specified period of
time. The Clg disks are then solvent extracted and analyzed for pesticides by GC/MS, GC/ECD,
or other suitable instrumental method.
Surface Wipe. Surface wipe methods are used to estimate the surface pesticide residue
loading on hard surfaces such as floors, furniture, window sills, counters, toys, and other surfaces
and objects a child may contact. Surface areas being sampled must be non-porous and relatively
smooth in texture. There are several methods that have been developed but all are similar in that
a material, generally cotton gauze or some filter material, often wetted with a solvent
(isopropanol or water), is used to wipe a specified surface area (Wright et al., 1993; Camann et
al., 1996; Lioy et al., 1998; Lu and Fenske, 1999). The collection material is then extracted and
analyzed for pesticides by GC/MS, GC/ECD, or other suitable instrumental method.
Selection of practical, representative surfaces for monitoring can be one of the most
51
-------
difficult issues associated with the collection of environmental samples for the estimation of
children's dermal exposures. Financial and physical resources generally limit the number of
samples that can be collected and analyzed at any one location making those that are collected
critical to the success of the study. Children contact a wide variety of surfaces during their
activities and, as previously discussed, the level of activity, surface type, and the number of
surface contacts are all important variables. While the study design and field sampling protocols
can define the appropriate criteria, the general surface types, and the general sample collection
locations, the ultimate decision for sample collection is the responsibility of the field sampling
personnel and relies to a great extent on their experience and training. Each home or daycare
center situation requires decisions to be made that are specific to that particular home or daycare
center and the activities of the children in those locations. The following are some general
guidelines for determining appropriate sampling locations. The area and surfaces sampled
should be:
• representative of where the child spends the majority of his/her time while awake,
• representative of the surfaces that the child frequently comes in contact with,
• amenable to the designated methods of sampling, and
• surfaces for which empirically-derived transfer coefficients are available.
Information pertaining to the first two guidelines is generally obtained through discussions with
the child's caretaker and/or by observation of the child's activities. Questionnaires can also be
developed to provide a systematic approach to defining the areas and surfaces appropriate for
sampling.
The preceding paragraphs provided a brief overview of the generally available methods
for measuring pesticide residue surface loadings. In NERL's children's exposure measurement
studies, the most commonly used methods to measure surface pesticide residue loadings are
surface wipes and the C18 surface press sampler. The following is a more detailed discussion of
these methods.
The surface wipe method used in the recent NERL children's exposure studies uses 4-in x
4-in, 6-ply, cotton dressing sponges wetted with pesticide grade isopropanol as the collection
media. The surface to be sampled is wiped with an isopropanol dampened dressing sponge hi
one direction while frequently exposing a fresh surface of the wipe. The surface is then wiped in
a perpendicular direction with the same wipe. Once this is complete, the first wipe is placed in a
storage container and a second wipe is prepared and the process is repeated with this second
wipe. The second wipe is added to the container holding the first wipe. Samples are stored
frozen (-20 °C) and analyzed by solvent extraction followed by GC/ECD, GC/MS, or other
appropriate analytical method.
A total sampled area of 930 cm2, representing an area with dimensions of 30.5 x 30.5 cm
(12x12 inches), is generally sampled when collecting samples from a flat surface. Other areas
52
-------
may also be used to accommodate spaces available. The area sampled for irregular shaped
surfaces may be measured and determined on an individual basis. Smaller surfaces may be used
if high concentrations are suspected or if there is limited area available for sampling. The actual
surface area sampled must be determined and recorded. This method should not be used on
surfaces that may be damaged by alcohol.
The surface press method used in recent NERL children's exposure studies consists of a
specially constructed sampling device and utilizes C,g extraction disks (3M Empore) as the
transfer/collection medium. The sampler is based on the design of the sampler described by
Edwards and Lioy (1999). Two 90 mm,C18 extraction disks are mounted in a specially
constructed sampling device constructed of Delrin polymer and having a total mass of 1340 g.
The two disks provide a net surface contact area of 114 cm2 and a contact pressure of 11.8 g/cm2.
The disks are secured in the surface press sampler by means of a clamping system and during use
are placed in direct contact with the surface being tested. The press sampler is left in contact
with the surface for a prescribed period (generally 2 or 5 minutes) after which time it is lifted
from the surface and the disks carefully removed, folded, and placed in a pre-cleaned and
labeled, glass storage container. Samples are stored frozen (-20 °C) and analyzed by solvent
extraction followed by GC/ECD, GC/MS, or other appropriate analytical method. Testing is on-
going in NERL to finalize the procedures for use of this method for a wide range of current use
pesticides, particularly for the pyrethroids.
It should be recognized that selection of the extraction and analysis methods for use with
these sampling media is critical to successful measurements of surface loading. Because of the
low surface loadings that may be encountered in residences and daycares, the extraction method
must have high recovery of the target compounds and the method detection limits must be
sufficiently low. Levels of pesticides measured in households are generally very low. In a recent
study, transferable residue concentrations measured from carpet with a PUF roller were in the
range of 0.03 to 0.61 ug/m2 in a room with a recent application of diazinon (Lewis et al., 2001).
There are many factors that ultimately guide the selection of sampling and analysis methods.
Among them are the sensitivity of the analytical instrument that will be used for the analysis of
the extract, the type of analytical detector, the final volume to which the sample extract is
concentrated, loading or concentration of the target compounds on the original sampled surface,
and the transfer efficiency of the target compounds from the surface to the sampling media. All
of the above parameters can be optimized by conducting pilot or scoping studies to field test
methods for the pesticides of interest before a large field study is conducted. Although
previously collected samples can initially be screened and the extracts adjusted by concentrating
or diluting specific samples to insure that they fall within the analytical range, this is not advised
due to the additional handling and potential associated errors as well as the inefficiency of
multiple analyses of the same sample, hi general, liquid injections of extracts on a GC/MS
system will be measurable in the low pg/uL (ng/mL) range while operating in the selective ion
mode and, therefore, an injected sample must be in this range to be measurable. If an area of 930
cm2 is wiped using the surface wipe method, the sample extract is concentrated to a final volume
53
-------
of 1.00 mL, and the transfer efficiency is near 100%, the initial surface concentration must be
approximately 11 pg/cm2 (0.11 ug/m2) in order to be measurable. Increasing the sampled surface
area, concentrating the extract to a smaller volume, or optimizing the instrument are all viable
steps to decreasing the detection limit. It should be noted that simply increasing the size of the
sampled area may not be sufficient to increase the measurable pesticides since detection of the
pesticides may also be affected by interferences associated with the sampled area. Precision for
the surface press and surface wipe samples should be ± 25% for duplicate samples and the
accuracy, expressed as the percent recovery of spiked samples, should be in the range of 75 to
125%.
6.5 Exposure Factor/Questionnaire Information
The numerous data parameters that need to be considered when estimating dermal
exposure were described above. Exposure factors are used in conjunction with the
environmental measurement data to estimate exposure. Collection of exposure factor
information is often accomplished through the use of activity diaries and questionnaires.
Questionnaires break the day into discrete time periods of interest. Activity diaries can provide
information as a function of time over the entire day. At a minimum, the diaries and
questionnaires must include a notation of the time period of interest, indoor versus outdoor
activities during this time period, clothing levels, and microenvironment/macroactivity
information. Table 6-3 shows the microenvironments/macroactivity combinations and surfaces
for which information is collected. An example of a time-activity diary that can be used to
collect the exposure factor information required when assessing dermal exposure using the
macroactivity approach and information for estimating inhalation exposure was depicted in
Figure 5-1 in Section 5.5.
6.6 Estimation of Transfer Coefficients
The transfer coefficient for each microenvironment/macroactivity must be empirically
determined from controlled laboratory experiments or field studies, hi laboratory studies,
experiments can be designed to develop transfer coefficients for a variety of micro-
environment/macroactivity combinations, hi field studies, transfer coefficients are determined
for a discrete period of time for a single microenvironment/macroactivity combination. For
children, it is necessary to record activity patterns (i.e., contact activities, activity level, amount
of clothing, locations), collect dermal wipes (i.e., based on exposed skin and activity
information), and measure transferable surface residue loadings (i.e., from the location where the
child spends the majority of his/her time). As an alternative to the dermal wipes, cotton
dosimeters may be worn in a specific microenvironment/macroactivity for a defined period of
time. These collected parameters can then be substituted into the equation to calculate the
transfer coefficient.
The transfer coefficient, TCme/ma, provides a measure of dermal exposure resulting from
54
-------
Table 6-3. Microenvironments/Macroactivity Combinations and Surfaces for Which Activity
Data Are Collected
Microenvironment
Indoors at Home
-Carpet
-Hard Floor
-Upholstery/Bedding
Outdoors at Home
-Grass
-Dirt/Soil
-Paved Surfaces
Indoors at Daycare
-Carpet
-Hard Floor
-Upholstery/Bedding
Outdoors at Daycare
-Grass
-Dirt/Soil
-Paved Surfaces
Macroactivity
Active Play
r-^v-cf
*S*V* ' st'JDc^' •** ? '-.
£Cr- **.;*?#
&',., t^ V^fe ,
^y^flvf^'^
Quiet Play
* ', y'>--*'
,v- * j
•' $*>'-.*»' , ^:'-^f
% * 3 > •*«-'' ^ "L
£• „>' * i ".fj" •"^T.*"
• <»« ,\.,'i^U.',- • <"
j/,,/^( -.;«»!,,«
Sleeping
^IS:
-*Mi^'U*W^^
-^ i-s^^4.?:W.' M«
Eating
contact with a contaminated microenvironmental surface while engaged in a specific
macroactivity. The transfer coefficient takes into account the fraction of the surface residue that
is transferred from a surface to skin, the character of the microenvironmental surface that is
contacted, and the area of the microenvironmental surface that is contacted during a time
increment for a given activity. TCder can be defined as follows:
TCme/ma = (Edme/ma)/[(Csurf)(ADme/ma)]
(13)
55
-------
where
TCme/ma = transfer coefficient for the microenvironment/macroactivity (cm2/h)
Edme/ma = dermal exposure for a given microenvironment/macroactivity combination
over a 24-h period (^g/d)
Csurf = surface loading (total or transferable) measured in the microenvironment
(Hg/cm2)
ADme/ma = activity duration that represents the time spent in each micro-
environment/macroactivity combination with a specific clothing pattern
for the child that would affect the surface area available for transfer over a
24-h period (h/d)
The transfer coefficient relates to the specific type of pesticide residue loading measured.
For example, if a transferable pesticide residue loading is measured, then the transfer coefficient
is related to the transferable residue. However, if a total pesticide residue loading is measured,
then the transfer coefficient must be related to the total residue. It is important to keep this
distinction in mind when performing environmental measurements. The same sampling methods
must be used both for the field surface loading measurements and in the experiments to
determine the transfer coefficients for the same microenvironment/macroactivity combination.
56
-------
7.0 APPROACH FOR ESTIMATING DIETARY INGESTION EXPOSURE
7.1 Introduction
Total ingestion of pesticides by children from foods and beverages involves two major
components: (1) directly ingested foods brought into the home or other eating places containing
pesticide residues primarily from agricultural applications (i.e., dietary ingestion exposure, or
simply dietary exposure), and (2) indirect ingestion exposures associated with additional
contamination of foods during consumption by children. This section focuses on the first
component and is termed dietary exposure because it is associated with pesticides that are
inherent to the foods themselves, and not how they may be further contaminated by the activities
of the child during consumption in the residential or other eating environment. Approaches for
estimating indirect ingestion from foods, as well as other pathways of indirect ingestion exposure
not associated with diet, are included in Section 8.0, Approach for Estimating Indirect Ingestion
Exposure.
For certain exposure scenarios (e.g., chronic exposures) and in the absence of recent
pesticide applications, the dietary component of ingestion exposure is likely the dominant
exposure pathway to pesticides, and potentially the most significant of all pathways for aggregate
exposure. Such scenarios occur in particular when handling of foods by the child is minimal and
when additional pathways of contamination, such as from surface deposits of residues resulting
from outdoor air, track-in of particles, and/or indoor sources of pesticides, are minimal. Then,
agricultural sources are typically the most significant sources of dietary, and hence aggregate
exposure.
Personal monitoring methodology for measuring dietary exposure of children is based on
the duplicate diet method for collection of food samples from study subjects with subsequent
measurement of pesticide residues in the collected food samples. These procedures provide the
ability to measure the importance of diet relative to other pathways of personal exposure and they
directly measure, with reasonable certainty, the exposure from all foods and beverages in the
diets presented to the child during the monitoring period. Children's diets differ significantly
from those of adults and children eat more than adults relative to their body weights. The diet of
newborns is limited exclusively to breast milk or formula, both of which may expose infants to
significant concentrations of environmental contaminants (Mukerjee, 1998 and Chance et al.,
1998). Infants and young children eat more fruit and milk products in proportion to their body
size and have a less varied diet than adults, hi addition, there may be tremendous variability in
diet among young children of similar ages and for a single child at different periods in time.
Some infants and toddlers go through phases where only a few preferred foods are eaten for
weeks and months at a time. Such a limited diet may potentially increase dietary exposure of
young children to environmental contaminants such as pesticide residues in fruit (NAS, 1993 and
Goldman, 1995). The numerous factors that influence the diets of young children and resulting
health implications make it extremely important to accurately assess their dietary intake of
57
-------
pesticides.
7.2 Summary of Data Requirements
Dietary exposure to a pesticide is defined as the amount of pesticide ingested in the foods
and beverages consumed by a child over some reference exposure period, exclusive of any
additional contamination occurring during the actual process of eating the foods, as discussed
above. Thus, exposure to pesticides in drinking water may also be included in estimating dietary
exposure. Depending on dietary collection objectives and economic considerations, foods may
be collected and analyzed as independent items or collections of items that are combined for
analysis. A summary of the data requirements for this approach is presented in Table 7-1.
Table 7-1. Data Requirements for Estimating Dietary Ingestion Exposure
Parameter
Measurement
How Collected
Units
Ef = S CfWf
f
cf
wf
food item or collection of items
concentration of contaminant in
foodf
weight of food f
Analyze food item or items
Weigh food item or items
ug/kg
kg/d
7.3 General Considerations
Dietary samples are specific to the subject being monitored and are typically collected
over intervals of one day, although other sample collection intervals may be used. Dietary
samples can be collected for several consecutive days, several non-consecutive days, or at widely
spaced times over weeks, months, or seasons. In most studies, the caregiver of the child will
prepare a duplicate plate by measuring or estimating duplicate portions of each food given to the
child. The portions are identical to those served to the child in all aspects of preparation, type of
food, and amount of food. Following the eating activity by the child, portions are adjusted to
account for foods not consumed, thus providing a duplicate diet sample. The distinction between
a duplicate plate and a duplicate diet is typically more significant for children than adults because
significant quantities of food may be left uneaten by the child. To accurately measure dietary
exposure, samples must be collected for all foods and beverages consumed, including those
obtained away from home at restaurants, schools, day cares, etc. The caregiver will often be
58
-------
responsible for recording a diary of the type and amount of each food the child consumes.
Supplemental questions are answered by the caregiver that allow evaluation of both the
completeness and representativeness of the collected sample, and hygiene and dietary habits of
the child. Duplicate diet samples are often separated into solid foods and beverages during the
monitoring period because of analytical and economical considerations. Drinking water can be
included in the beverage samples or collected separately. Both samples (i.e., solids and
beverages) are composited to create two samples for the monitoring period. This allows for an
exposure estimate for the dietary pathway that is equivalent to other pathways being measured.
In some studies, individual foods may be collected. This allows subsequent compositing in the
laboratory which may allow for improved detection limits and/or selection of foods that are more
likely to contain pesticide residues.
Sample collection containers should be sufficiently large for the largest sample that might
be collected or multiple containers must be provided. Container materials should neither add the
contaminant of interest (or analytical interferences) to the food sample nor cause losses of the
contaminant of interest from the collected foods. Containers should be made of materials that
will withstand transport, handling, and in some cases, freezing. Storage and transport of samples
are normally important parameters to prevent sample spoilage during collection. Samples should
be stored and shipped refrigerated or frozen.
7.4 Monitoring Method
To monitor dietary ingestion exposure of children, the duplicate diet methodology is
used. This is a well established method that has been used in several monitoring studies (Berry,
1997, Thomas et al., 1997, and Melnyk et al., 1997). Since children are the targeted subjects,
caregivers are trained to collect and record information on duplicates of foods consumed using
visual estimation procedures. Specifics of the sample collection are determined in the study
design prior to field activities. NERL has developed a dietary model and database system
(DEPM, Tomerlin et al., 1997) to assist in designing dietary monitoring studies and interpreting
the results of composite diet sampling. The DEPM includes both consumption and pesticide
residue data from existing notional monitoring programs. Consumption information for children
is included. DEPM uses historical food information to estimate total daily intake of pesticides,
and food groups and items that are major contributing factors to dietary exposure. DEPM is
available at http://www.epa.gov/nerlcwww/depm.htm.
Typically, analyzing composited food samples is an integral part of determining dietary
exposure. All methods for collection, storage, mixing, extraction, and analysis should be
selected and implemented in such a way that they provide residue concentration data that are of
known and acceptable quality for meeting the overall study objectives. Composited food
samples present unique analytical challenges because the samples are very diverse and may
contain varying amounts of fats and other interfering substances. In most cases, relatively few of
the individual food items in a composited sample contain residues. While these residues may or
59
-------
may not be present at high levels in the individual food item, the compositing process dilutes
them by combining the contaminated item or items with a large mass of food which does not
contain any residues. Thus, sensitivity of the analytical method for foods is extremely important.
Diet is often the limiting pathway hi multi-pathway assessments due to the relative
sensitivity of food analytical methods versus those for other media. A typical diet (even for a
child) may result in collection of 100 tO 500 g/d for composite solid food or beverage samples.
Typically, 25 g is the maximum practical aliquot for analysis. This limitation allows for the
analysis of only 5 to 25% of the total daily solid food or beverage sample. Analysis of other
media is not subject to such sample size limitations and it is possible to analyze the entire sample
collected in a one day period, and in some cases, even longer. Even with equivalent analytical
sensitivity among media, overall method detection limits are 10 -100 times higher for food than
for other media due to relative amount of the daily sample analyzed.
Analytical methods to obtain pesticide concentrations for composited food samples have
been developed with the goal of 1 ng/g detection limit. Specific detection limits for several
pesticides in daily composited solid food samples are listed in Table 7-2 with the recoveries from
medium fat composite diet samples (U.S. EPA, 2001).
7.5 Exposure Factor Information
Activities affecting dietary exposure are recorded in food diaries and supporting
questionnaires. This information includes what foods were eaten, where the foods were eaten,
and how much was eaten. Supporting questionnaires obtain other important information such as
whether the diet was typical, activities that occurred that may influence exposure like recent
application of pesticides, etc. The NERL Hygiene and Dietary Habit Survey and food diary are
presented in Appendix B.
60
-------
Table 7-2. Method Detection Limits and Pesticide Recoveries8 from Medium Fat Composite
Diet Samples Fortified at 1, 5 and 10 ng/g.
Pesticide
Trifluralin
Phorate
Hexachlorobenzene
Dicloran
Simazine
Atrazine
Terbufos
Fonofos
Diazinon
Chlorothalonil
Acetochlor
Alachlor
Aldrin
Malathion
Metolachlor
Chlorpyrifos
Parathion
Dacthal
Isofenphos
g-Chlordane
Endosulfan-I
a-Chlordane
Dieldrin
DDE
Endrin
ODD
cis-Permethrin
trans-Permethrin
%Recoverv
1 ne/e
93
80
68
41
56
101
80
99
101
77
184
106
108
109
78
97
101
91
80
62
96
69
115
80
0
111
175
175
5ne/g
104
94
82
86
86
100
96
101
102
75
95
88
84
106
92
97
119
94
99
81
82
82
92
94
89
145
120
134
10 ng/g
108
113
92
115
85
106
113
105
106
124
110
104
99
115
105
102
117
105
111
95
96
97
99
102
73
183
105
102
MDLb
0.4(1)
1.7(5)
0.4 (1)
1.7(5)
1.9f5}
2(5)
0.3 (1)
1.5(5)
1.4(5)
0.5 (1)
1.4(5)
0.4(1)
1(5)
1.7(5)
0.2 (1)
0.5 (1)
1.8(5)
0.3 (1)
0.4 (1)
0.2(1)
0.4(1)
0.2(1)
0.4(1)
0.2(1)
2.4 (10)
5.3 (10)
3.5 (10)
3.2 (10)
a n = 7 for each concentration.
b Method detection limits were
parentheses. Method detection
(Rosenblumetal.,2001)
calculated using either 1, 5 or 10 ng/g fortification levels as indicated in
limits are not reported for analytes with recoveries less than 60%.
61
-------
8.0 APPROACH FOR ESTIMATING INDIRECT INGESTION EXPOSURE
8.1 Introduction
Ingestion exposure by indirect pathways has been identified as a potentially significant
route of pesticide exposure for infants and young children (Cohen Hubal et al., 2000). Indirect
ingestion exposures occur when children place objects that have become contaminated with
pesticides, including their hands, in their mouths. Pesticides are ingested as a result of transfer
from the object, or, for foods, when they are consumed.
In addition to the dietary ingestion exposures associated with the foods that children eat
(Section 7.0), the manner in which children handle food as they eat may also impact their
exposure to environmental contaminants. Small children are less likely than adults to consume
food in a structured environment. Small children may sit on the floor or lawn to eat and often
pick up and eat foods that have fallen on the floor. Infants and young children also eat most of
their food with their hands. Increased exposure occurs when children handle and eat foods that
have come in contact with the floor or other contaminated residential surfaces (Melnyk et al.,
2000; Akland et al., 2000) and hands. Indirect ingestion associated with foods consumed,
together with dietary ingestion associated with contaminants inherent to foods, constitutes total
ingestion from the dietary pathway.
Children's mouthing behaviors also contribute to the potential for indirect ingestion
resulting from contact with contaminated objects and surfaces in the environment. Sucking and
mouthing hands and objects are natural behaviors in childhood development. Infants are born
with a sucking reflex, providing them with both nutrition and a sense of comfort or security. If
infants do not receive unrestricted breast feeding, they will suck on a pacifier, thumb (or other
finger), or other object like a blanket or stuffed animal. As infants develop, they begin to explore
their world through mouthing (Groot, 1998). During this stage of development, children put
almost everything that they contact into their mouths for a few seconds. Young children may
also begin to use the mouth as a third hand, placing some objects in the mouth in order to manage
them.
Teething is another important stimulus for mouthing activities. Biting and chewing on
fingers and objects to relieve the discomfort of teething may be extensive. Teething usually
begins between 4 and 7 months of age, but may start several months earlier or later. As with all
childhood behaviors, mouthing activities vary significantly from child to child and, therefore, the
impact on exposure will also be highly variable.
8.2 Summary of Data Requirements
Because it would be too burdensome and costly to collect all the data required to apply
the microactivity approach as presented hi Section 3.4, a macroactivity approach is presented
62
-------
here to provide a simplified assessment of indirect ingestion exposure to an individual based on
measurement data collected in the field. In this approach, objects (including hands and food) that
are commonly handled, mouthed, and/or ingested are identified in the field. The residue loadings
on these objects are measured directly or estimated from surface concentration measurements.
General information relating to the frequency and nature of these mouthing and ingestion
activities is also collected. Data on the fraction of residues that may be removed from an object
during mouthing that has been obtained in the laboratory experiments is then required to
complete the assessment. A summary of the data requirements for this approach is presented in
Table 8-1.
Table 8-1. Data Requirements for Estimating Indirect Ingestion Exposure
Parameter
Measurement
How Collected
Indirect Ingestion Exposure - Macroactivity Approach
Eing/mi = (CJCTEJCSAJCEF)
X
cx
TEX
SAX
EF
Hand, object, food item or
anything else that enters the mouth
Contaminant loading on x
Transfer efficiency of contaminant
from x to mouth
Area of x contacted by mouth
Frequency of indirect ingestion
events over a 24-h period
Wipes, washes or surface
samplers, samples of handled
food
Measured in the laboratory,
estimated from the literature
Questionnaire
Questionnaire
Units
u.g/cm2
unitless
cm2/event
event/d
8.3 General Considerations
Ingestion exposure occurs by direct ingestion of foods containing pesticide residues.
These residues are the result of agricultural use of pesticides and are in the food when the food is
brought into the residential environment. Ingestion exposure may also occur by indirect
ingestion of residues on objects, hands, and food that are placed in the mouth. These residues are
transferred from surfaces and objects in the residential environment directly to hands, to food, or
additionally from hands to food. Indirect ingestion exposures are difficult to quantify and assess
because there are no methods for directly measuring contaminants that are ingested by these
63
-------
pathways.
Instead, measurement of residues on hands, objects, and foods collected at specific time
points are used to estimate ingestion exposures over the time frame of interest. Measurements of
contaminant loading collected at a single point in time, however, may not reflect changes in
loading which occur prior to, or subsequent to, sampling (e.g., evaporation or removal by hand
washing or mouthing). Contaminant loading over time can vary significantly and is often the
result of discrete events. Thus, current sampling techniques result in an integrated loading over
extended time periods, and variations in time cannot be characterized. To facilitate interpretation
of these data, measurements of residues on hands, objects, and handled foods need to be related
to activities that occur in the same time interval. As much as is possible, exposure media
concentrations need to be linked directly to contact activities.
To conduct a more detailed analysis of the time course of exposure, as is the goal of an
exposure model like SHEDS, very detailed time-sequence activity data are required. To collect
this type of data, a diary survey structure designed to collect sequential location/activity data for
each discrete behavior of interest or videotaping is required. The burden of such a diary survey
precludes inclusion in the type of children's exposure study covered by this protocol and should
therefore be considered for a separate study.
One additional consideration: in the time frame of concern for this scenario (short term
following an application), exposure resulting from ingestion of soil and house dust is assumed to
be less important than indirect ingestion of residues. If during the preliminary screening
assessment, soil and dust ingestion pathways are identified as potentially important, these can be
easily addressed by the addition of dust and soil samples to the required field measurements.
8.4 Monitoring Methods
To estimate the contaminant loading on the objects which a child may contact by indirect
ingestion pathways, the following field samples are required:
• Samples of residue loadings from any residential surfaces that are frequently mouthed
(e.g., surface press on coffee table),
• Samples of residue loadings from the surfaces of objects that are frequently mouthed
(e.g., surface wipe on toy),
• Samples of residue loadings from the child's hands or other body parts that are frequently
mouthed (e.g., hand wipe),
• Samples of foods that have been handled in the child's normal eating environment (e.g.,
cheese handled by child prior to eating), and
• Samples of foods that have contacted surfaces during eating (e.g., cheese that has been
placed on counter tops, floors, or high chair trays).
64
-------
Information on the relevant surface sampling techniques has been included in Section 6
on dermal exposure. Removal techniques used to measure residues on smaller objects, hands,
and foods are discussed below.
Surface Loading Measurements. Surface wipe, press, or rolling methods are used to
estimate the total or potential amounts of pesticides available for transfer from surfaces such as
floors, furniture, window sills, counters, and toys. There are several methods that have been
developed, as described in Section 6.4, but all are similar in that a material, generally cotton
gauze or some filter material, either wetted with a solvent (isopropanol, water, saliva simulant) or
dry, is used to wipe, press, or roll on a specified surface area. Appropriate methods need to be
selected based on the type of surface (e.g., wipes are applicable for hard surfaces, but not for
carpet). The collection material is then extracted, and analyzed for pesticides by GC/MS,
GC/ECD, or other suitable instrumental method.
Hand Wipe or Rinse. Hand wipe and rinse methods are used to estimate the total or
potential amounts of pesticides available for mouthing. Handwash sampling procedures can be
standardized to ensure that they are operator-independent (Davies, 1980). Skin wiping
procedures are inherently operator dependent. Removal sampling techniques are limited in that
these measure only what can be removed from skin at the time of sampling rather than the actual
skin loading. Findings suggest that data collected using removal techniques are difficult to
interpret and require appropriate laboratory removal efficiency studies for use. However,
because hand wipes are being used here to assess indirect ingestion exposure and not dermal
exposure, the removal is likely more representative of what is available for indirect ingestion
than for dermal absorption. As such the major limitation is that current sampling techniques do
not reflect loadings or losses which occur subsequent to sampling. NERL is addressing issues
related to hand wipe sampling and is developing and evaluating standardized procedures.
Collection of Handled Food. Individual samples of foods that have been handled by the
child can be collected to estimate the pesticide loading on the food items caused by contact with
contaminated surfaces and hands. One approach used by NERL has been to identify food items
that a child in the study was known to handle when eating. During the monitoring period, the
caregiver for the child collects one set of the individual food items that were not touched by the
child and a second set that were touched (handled) by the child. Analyses of the two sets of the
individual food items provide the amount of pesticides transferred onto the foods. In other
studies, samples of foods have been contacted with surfaces by the monitoring technician to
directly measure the potential for transfer.
Soil and Dust Sampling. Although not included as part of this scenario, soil and dust
samples may be collected if it is determined that those pathways are potentially important for
indirect ingestion.
65
-------
Selection of Objects for Sampling. The objects to be sampled should be:
• representative of the objects that the child frequently comes in contact with and
• amenable to the designated methods of sampling.
Information pertaining to these two points is generally obtained through discussions with the
child's caregiver and/or by observation of the child's activities. Questionnaires can also be
developed to provide a systematic approach to defining the objects appropriate for sampling. All
samples should be collected such that the measurements can be related in tune to the activity data
in the questionnaires.
Sampling Considerations. Many of the sampling considerations for the indirect ingestion
route of exposure are similar to those presented for the dermal route. However, there are several
considerations specific to this route and the residue removal and food samples that must be
collected. Outlined below are the additional issues that should be considered when designing
and collecting samples associated with the indirect ingestion route in a measurement-based
assessment.
• Physical surface characteristics, contaminant surface loading, sampling material, and
wipe sampling procedures all influence accuracy and precision of measurements. (Fenske,
1993)
• Area dimensions of objects to be monitored should be based on a practical limit of
detection (LOD) for the analytical method that will be used. Samples being analyzed by a
laboratory method that is very sensitive (low LODs) will require a smaller sampled area
than samples being analyzed by a method that is less sensitive (high LODs). Detection
limits should be sufficiently low to insure that not detected values represent
concentrations considered insignificant as defined by the study goals.
• Practical limits of detection should also be considered in choosing the solvent for the
removal techniques. While a saliva simulant is likely to give a sample that is more
representative of a transferable residue, isopropanol may provide a sample that is easier to
analyze. Requirements for method detection limits and performance were discussed in
Section 6.4.
• Hand wipe and hand wash techniques assess contamination adhering to an individual's
skin at the time of sample collection. Measurements of skin loading do not reflect losses
which occur subsequent to sampling; e.g. evaporation or removal by hand washing. Skin
loading over time may vary significantly and may be the result of many discrete events.
Current sampling integrates dermal loading over extended time periods. Therefore,
variations in time cannot be characterized.
• Food items should be collected that are of sufficient quantity such that there will be
leftovers for collection, both handled and not handled. Alternatively, use standardized
food items that can be contacted with contaminated surfaces so that sources of
contamination can be identified, both within and among exposure scenarios.
66
-------
8.5 Exposure Factor Information
To estimate indirect ingestion exposure, information must be collected to describe the (1)
characteristics of the child, (2) activity information associated with mouthing and ingestion of
objects by the child, and (3) information on the transfer of residues from the objects to the mouth.
Characteristics of Child. The minimum information required to characterize the child is
the child's age, weight, gender, and hand surface area. These variables are used to estimate
ingestion rates and may be used to estimate mouthing and related behavior.
Activity information. An activity questionnaire is used to collect information on: (1) the
objects that are mouthed or eaten most often by a child and (2) the characteristics of the activities
that potentially result in indirect ingestion of the contaminant of interest. By collecting
information on the important objects, field sampling can be directed to collect residue loading
samples from these items. Information on mouthing characteristics (e.g., frequency, surface area
mouthed), hand washing practices, eating environment, and the likelihood of the child handling
food items should be linked to the sampled items to facilitate assessment of indirect ingestion
exposure. Examples of the information to be collected and the types of questions required to
collect the relevant activity information are presented in Figures 8-1 and 8-2. Figure 8-2 presents
examples of questions from the NERL Hygiene and Dietary Habit Survey, a copy of which is
included in its entirety in Appendix B of this document.
Object-to-Mouth Transfer Efficiencies. Object-to-mouth transfer efficiency may be a
function of object surface characteristics (e.g., plush vs hard), and mouthing mechanics (e.g.,
sucking vs licking). The need to develop residue transfer data for mouthing activities was
identified in the NERL Dermal and Non-dietary Exposure Workshop conducted in 1999.
Laboratory studies are being conducted by NERL using a surrogate mouthing method to identify
the important parameters for characterizing these transfer efficiencies and to develop a set of
transfer efficiency data.
Soil and dust ingestion rates. Indirect ingestion of soil and dust has been monitored in
fecal samples using tracer elements (Binder et al., 1986; Calabrese et al., 1989; Van Wijnen et
al., 1990; Davis et al, 1990; Calabrese et al., 1997). These studies require collection of dietary
data and concentrations of contaminants in residential soil and dust to link the tracers to ingested
soil and then to estimate ingestion of contaminants. Results of the limited monitoring conducted
using this technique are currently used to provide bounding estimates for soil ingestion which
can then be combined with information on the concentration of pesticides in dust and soil to
estimated indirect ingestion exposure by this pathway.
67
-------
Figure 8-1. Examples of data required for assessing indirect ingestion exposure and sample
questions.
HOME QUESTIONNAIRE
1. Hand surface area
2. Is your child currently teething?
3. Does your child, put toys or other objects in his/her mouth?
1. Frequently (greater than 10 time/hour)
2. Sometimes (2 to 10 times/hour)
3. Almost Never (less than 2 times/hour)
4. Please list the objects your child puts in his/her mouth most frequently
Object
1.
2.
3.
4.
5.
Portion put in mouth
Number of times/day
Where handled
Does you child lick or mouth surfaces?
1. Frequently (greater than 10 time/hour)
2. Sometimes (2 to 10 times/hour)
3. Almost Never (less than 2 times/hour)
What surfaces does you child lick or mouth most frequently? Please list surface and
location
a.
b.
c.
68
-------
7. How frequently does you child put his/her hands in his/her mouth?
Frequently (greater than 20 time/hour)
Sometimes (5 to 15 times/hour)
Occasionally (2 to 5 times/hour)
Almost Never (less than 2 times/hour)
During active play?
During quiet play?
8. How much of your child's hand does s/he put into his/her mouth?
a. thumb
b. 2 fingers
c. 4 fingers
d. whole hand
9. Does your child suck on his/her fingers when they are in the mouth?
10. Does you child put, his/her toes or feet in his/her mouth?
a. Frequently (greater than 10 time/hour)
b. Sometimes (2 to 10 times/hour)
c. Almost Never (less than 2 times/hour)
DAYCARE QUESTIONNAIRE (Ask for each participating child:)
1. Does s/he child, put toys or other objects in his/her mouth?
1. Frequently (greater than 10 time/hour)
2. Sometimes (2 to 10 times/hour)
3. Almost Never (less than 2 times/hour)
2. How frequently does s/he put his/her hands in his/her mouth?
1. Frequently (greater than 20 times/hour)
2. Sometimes (5 to 15 times/hour)
3. Occasionally (2 to 5 times/hour)
4. Almost never (less than 2 times/hour)
3. Please lists the 5 toys or objects that children put in their mouths most frequently and
where they are handled.
4. How are toys washed and recycled?
69
-------
Figure 8-2. Examples of questions included in the NERL Hygiene and Dietary Habit Survey
(included in Appendix B).
1. Does your child eat food with his/her lingers? What types?
1. Yes 1. Often
2. No 2. Sometimes
9. Unknown 3. Almost never
9. Unknown
2. Where does your child usually eat his/her meals when at home?
1. Kitchen 1. At table
2. Living room 2. High chair
3. Bedroom 3. Chair or couch
4. Dining room 4. Sitting on the floor
5. Other 5. Other
9. Unknown 9. Unknown
3. Where does your child usually eat his/her snacks?
1. Kitchen 1. At table
2. Living room 2. High chair
3. Bedroom 3. Chair or couch
4. Dining room 4. Sitting on the floor
5. Other 5. Other
9. Unknown 9. Unknown
4. What snacks does your child usually eat at home?
1.
2.
3.
4.
5.
5. How frequently does your child eat food off of the floor?
1. Often 2. Sometimes 3. Almost never
9. Unknown
70
-------
6. Does your child ever prepare or get his/her own food?
(for instance peel a banana, get a bowl of cereal, finger foods)
What foods?
1. Yes 1. Often
2. No 2. Sometimes
9. Unknown 3. Almost never
9. Unknown
7. Does an older brother or sister ever prepare or get your child's food?
(For instance peel a banana, get a bowl of cereal, finger foods)
What foods?
1. Yes 1. Often
2. No 2. Sometimes
9. Not applicable 3. Almost never
9. Unknown
8. Does your child ever eat food after it has dropped on the floor?
What foods?
1. Yes 1. Often
2. No 2. Sometimes
9. Not applicable 3. Almost never
9. Unknown
9. Does your child drink from bottles?
1. Yes 1. Often
2. No 2. Sometimes
9. Not applicable 3. Almost never
9. Unknown
71
-------
9.0 OTHER DATA COLLECTION
9.1. Questionnaire Data To Identify Sources and Usage of Pesticides in Residences and
Daycares
9.1.1 Introduction
The previous sections of this document have described the data requirements and
approaches for estimating children's aggregate exposure to pesticides. For the measurement
based approach described in the previous sections, time-activity diaries and questionnaires are
used to collect data on the exposure factors that are needed to estimate exposure by the different
routes and pathways. Well-designed questionnaires are also important to characterize sources,
transport processes, and parameters that may affect spatial and temporal distribution of pesticides
and environmental contaminants in human exposure studies. Information collected with
questionnaires during exposure measurement field studies can aid in the interpretation of the data
collected in measurement assessments and provide data for use in modeling assessments.
Exposures to pesticides and environmental contaminants may result from many different
sources and in many different microenvironments. Pesticide sources may include, but are not
limited, to applications for the control of agricultural pests, outdoor turf and landscape pests,
termite control, indoor pest control, and control of pests on pets. Pesticides may move or
translocate from their source and point of application. They move from one location to another
following several pathways. Pesticide applications may generate particles that drift from their
original source. In addition, depending on the physical nature of the pesticide active ingredient
and the formulation, vapors and/or pollutants sorbed to particles may result in pesticides or
contaminants moving from the source to deposit at other locations. Finally, the physical uptake
of residues and particles on an individual's hands, feet, or clothing or by adhesion on the fur of
pets such as cats and dogs may result in the physical translocation of contaminants or pesticides.
Pesticides and environmental contaminants in the air may also infiltrate into the homes, daycares,
schools and other buildings from the outdoors.
9.1.2 Administering Questionnaires
Site surveys and questionnaires are common methods to screen and characterize sources,
and aid in identifying transport mechanisms and exposure pathways. Furthermore, they can be
useful to gather general information regarding the study participants and their lifestyles and
activities, the home or facility under study, and other parameters that may affect exposure or the
interpretation of exposure measurement results.
Prior to the initiation of the study, the research team should concisely define the type of
information required to fulfill their research needs and evaluate the design to insure that while
effectively capturing the desired information an excessive burden is not placed on the study
72
-------
participants.
Surveys may be completed by field scientists or adult study participants. The survey team
should be available to address questions the participant may have regarding the survey. When
administering survey questionnaires that collect information on pesticide use, it is especially
important to have knowledgeable field team members who can provide assistance to study
participants to complete the questionnaires. Assistance may be particularly important when
querying the participants regarding specific products and pesticide applications because many
occupants of homes have little familiarity with specific terms, chemical classes, or product
groupings. To overcome some of the problems of obtaining accurate information about pesticide
use in residences, the field team may request to view areas where cleaners, pesticides and other
household products are stored in order to collect chemical names and registration numbers for
future identification. The problem of collecting accurate usage information may be even greater
when attempting to collect information in daycares or schools where pesticides are applied by
commercial applicators. In these environments, it is generally necessary to work with building
management and facility managers to obtain service and application records.
Following completion of questionnaires, a member of the survey team should review the
forms to insure completeness and legibility. Similarly, forms completed by the field team should
undergo a quality assurance check by the team lead to determine completeness, accuracy and
legibility.
9.1.3. Information on Sources to be Collected in Pesticide Exposure Measurement Studies
To obtain accurate information on pesticide sources and usage in residences, a simple
questionnaire should be designed that collects information on what pesticides were used, when
they were applied, where applied, and how applied. Figure 9-1 presents examples of questions
that can be used to collect this information. The example questions would be used to address the
specific scenario described in Section 4 for short-term exposure during a period of one to seven
days following application. The sample questions are not all inclusive. Additional questions will
be required to address different exposure scenarios. A different set of questions would be
required to assess long-term exposure to pesticides. Additional questions would also be required
for population modeling-based approaches for exposure assessment. Researchers hi NERL are
currently developing a questionnaire that will be used with this protocol.
In addition to the questions that specifically address recent pesticide applications in the
home, questions should be included to determine other potential sources of pesticides in the
home. Pesticide residues may be physically transported on the clothing, shoes and the body of
individuals from their workplace to home. Questions to determine occupational exposure as a
source might include those in Figure 9-2.
73
-------
Figure 9-1. Example questions use to collect information on pesticide usage in a residence.
1. Did anyone apply pesticides within your home, in your garden or in your yard within the
past 2 weeks?
Yes. (If yes, go to l.b. through l.h)
_No
Don't Know
1 .b. Where and when was it applied?
in the home (if checked, screen gives detailed list of choices for kitchen,
pantry, living room, bathrooms, bedrooms, under sinks, floors, at
baseboards, cupboards, window sills, at a specific site of infestation, etc.)
in the basement
in the garage
in storage areas
_outside along the walls
_under the crawl space
_in the yard
_in the garden
_on the pet (s)
_on a deck or wood surface
_on cement or patio surface
Don't know
(next screen gives choices of when applied)
today within 24-48 hours 3-5 days 1 week 2 weeks last month
1 .c. For indoor applications, how was it applied?
crack and crevice spray (liquid) along walls
sprayed (liquid) in the room
fogger (aerosol in a can)
dust
bait in a container
bait not in a container
applied to pet as a liquid or shampoo
_applied to pet as a powder
74
-------
1 .d. For non-indoor living area applications, including crawl space, how was it
applied?
foundation spray (liquid) along walls
dust or pellets on yard, garden or lawn
spray on yard, garden or lawn
bait in a container
bait not in a container
applied to pet as a liquid, shampoo, or powder
don't know
1 .e Who applied the pesticide?
applied by yourself
applied by another adult in the home
___applied by a commercial applicator
don't know
1 .f. For what purpose was the pesticide applied?
ants mosquitos fungi/molds/bacteria weed control
roaches other flying insects plant disease other purpose
fleas termites other insects don't know
1 .g. Did you have to mix the chemical with water before applying?
yes no
1 .h. Give the name and EPA number (if known) of the products that were applied
during the past 2 weeks. The EPA registration number is located on the label of
the product. (Photo to show example)
Pesticide #1: EPA Reg. No:
Pesticide #2: EPA Reg. No:
Pesticide #3: EPA Reg. No:
Pesticide #4: EPA Reg. No:
Pesticide #5: EPA Reg. No:
75
-------
Figure 9-2. Questions on occupational exposure to pesticides.
2. Does anyone in the home work in a manufacturing job that involves handling of
pesticides or who works in a facility where pesticides are produced or handled?
Yes No
2a. If yes, what pesticides?
Pesticide #1:
Pesticide #2:
Pesticide #3:
2b. If yes, are his/her clothes and shoes changed before leaving the facility?
Yes No
3. Does anyone in the home work in on a farm or in an agricultural job that involves
handling of pesticides or crops treated with pesticides? Yes No
3 a. If yes, what pesticides?
Pesticide #1:
Pesticide #2:
Pesticide #3:
Pesticide #4:
Pesticide #5:
3b. If yes, are his/her clothes and shoes changed before entering your home?
Yes No
76
-------
Additional questions with greater detail may be added for field studies involving
measurements of pesticide by children of agricultural farm worker's families. These questions
may include identification of local sources of agricultural pest control applications, proximity to
residences and daycares, direction from these sources, and questions related to potential spray
drift.
9.1.4 Information on Microenvironment Surfaces, the Structure and the Occupants
hi order to obtain accurate estimates of dermal exposure, it is important to collect
information on the surfaces that the child contacts in the residence or daycare. This information
will be used to determine the appropriate transfer coefficients and efficiencies to develop in
laboratory and field experiments and to use in the algorithms for estimating dermal and indirect
ingestion exposure. During field data collection, the type of flooring material should be
identified in each room where the child spends time. This may include hard surfaces such as
vinyl flooring, ceramic flooring, wood, and other materials. Carpet type (short nap, plush, etc.)
should also be recorded. This information should be recorded for all rooms that are occupied by
the child. Development of the questions to collect this information is on-going in NERL.
For most field exposure measurement studies, the information on the structure can be
limited to a simple diagram of the residence showing the locations of rooms in the structure and
the sampling locations. Detailed information on the construction materials, size, age, heating and
cooling systems, etc. are not required for the purpose of estimating exposure, although they may
be useful for understanding the measurement data. Similarly, detailed information on occupant
activities beyond that collected with the time-activity diaries described in the previous sections is
generally not required, but it may be useful for interpreting the measurement data.
The type of information to be collected on the structure and the occupant activities will be
determined by the study objectives. Superfluous information should not be collected as it
increases participant burden and resources for performing the field studies. If the study data
analysis plan does not include a purpose for collection of information about the structure or the
occupants, it should not be collected.
9.1.5 Additional Data Collection for SHEDS-Pesticide Model
Additional data are needed for the SHEDS-Pesticides model (described in Appendix A)
that are not required in exposure assessments that use the individual measurement-based
approach for which this protocol was developed. Some of those additional requirements for
pesticide usage include the following:
1. Number of Applications
2. Month First Applied
3. Time Interval Between Applications
77
-------
4. Day of Week Used
5. Reentry Interval
6. Scenario-Specific Area (e.g., Lawn, Garden, House)
7. Scenario-Specific Area with a Chemical
8. Scenario-Specific Area with the Chemical of Interest
9. Scenario-Specific Area with the Chemical of Interest via the Formulation
10. Scenario-Specific Area with the Chemical of Interest via the Formulation and Application
Method
11. Residences Treating Entire (vs. Spot Treatment of) Scenario-Specific Area with the
Chemical of Interest via the Formulation and Application Method
12. Number of Applications Treating Entire (or Spot Treated) Scenario-Specific Area with
the Chemical of Interest via the Formulation and Application Method
13. Area Treated for Total Area Application
14. Fraction of Total Area for Spot Treatment
15. Application Rate
78
-------
10.0 REFERENCES
ASTM (2000a). "Standard practice for sampling and selection of analytical techniques for
pesticides and polychlorinated biphenyls in air." ASTM D4861, In: Annual Book of ASTM
Standards, Volume 11.03, ASTM, West Conshohocken, PA.
ASTM (2000b). "Standard practice for collection of dislodgeable residues from floors." ASTM
D6333, In: Annual Book of ASTM Standards, Volume 11.03, ASTM, West Conshohocken, PA.
Akland, G. G., E. D. Pellizzari, Y. Hu, M. Roberds, C. A. Rohrer, J. O. Leckie, and M. R. Berry
(2000). "Factors influencing total dietary exposures of young children." J. Expo. Anal. Environ.
Epidemiol, 10(6, Part 2):710-722.
Berry, M. R. (1997). "Advances in dietary exposure research at the US Environmental
Protection Agency - National Exposure Research Laboratory." J. Expo. Anal. Environ.
Epidemiol., 7(1): 3-16.
Binder S., D. Sokal, and D. Maghan (1986). "Estimating soil ingestion: the use of tracer
elements in estimating the amount of soil ingested by young children." Arch. Environ. Health
41(6):341-345.
Bink, B. (1962). "The physical working capacity in relation to working time and age."
Ergonomics 5:25-29.
Calabrese E. J., R. Barnes, E. J. Stanek III,, H. Pastides, C. E. Gilbert, P. Veneman, X.Wang, A.
Lasztity, and P. T. Kostecki (1989). "How much soil do young children ingest: an
epidemiological study." Regul. Toxicol. Pharmacol 10:123-137.
Calabrese E. J., E. J. Stanek III, P. Pekow, R. M. Barnes (1997). "Soil ingestion estimates for
children residing on a superfund site." Ecotoxicol. -Environ. Saf. 36:258-268.
Camann, D. E., H. J. Harding, P. W. Geno, and S. R. Agrawal (1996). "Comparison of methods
to determine dislodgeable residue transfer from floors." EPA/600/R-96/089. U.S. Environmental
Protection Agency, Research Triangle Park, NC.
Chance, G. W. and E. Harmsen (1998). "Children are different: environmental contaminants and
children's health." Can J Public Health 89:S9-S15.
Cohen Hubal, E. A., L. S. Sheldon, M. J. Zufall, J. M. Burke, and K. W. Thomas (2000). "The
challenge of assessing children's exposure to pesticides." J. Expo. Anal. Environ.
Epidemiol.lO:638-649.
79
-------
Davis, J. E. (1980). "Minimizing occupational exposure to pesticides: Personnel monitoring."
Res. Rev. 75:33-50.
Davis S., P. Waller, R. Buschbom, J. Ballou, and P.White (1990). "Quantitative estimates of soil
ingestion in normal children between the ages of 2 and 7 years: Population-based estimates using
aluminum, silicon, and titanium as soil tracer elements." Arch. Environ. Health 45:112-122.
Duan, N. (1982). "Models for human exposure to air pollution." Environ. Int. 8:305-309.
Edwards, R. D. and P. J. Lioy (1999). "The EL sampler: A press sampler for the quantitative
estimation of dermal exposure to pesticides in housedust." J. Expo. Anal. Environ. Epidemiol.
9:521-529.
Erb, E. (1981). "Applying work physiology to occupational medicine." Occup. Health Safety
50: 20-24.
Esmen, N. A. and T. A. Hall (2000). "Theoretical investigation of the interrelationship between
stationary and personal sampling in exposure estimation." Appl. Occup. Environ. Hyg. 15:114-
119.
Fenske, R. A. (1993). "Dermal exposure assessment techniques." Annals Occup. Hyg.
37:687-706.
Fortune, C. R. (1997). "Round-robin testing of methods for collecting dislodgeable residues
from carpets." EPA/600/R-97/119. U.S. Environmental Protection Agency, Research Triangle
Park, NC.
Goldman, L. R. (1995). "Children - unique and vulnerable environmental risks facing children
and recommendations for response." Environ Health Perspect. 103(suppl 6):13-18.
Gordon, S. M., P. J. Callahan, M. G. Nishioka, M. C. Brinkman, M. K. O'Rourke, M. D.
Lebowitz, and D. J. Moschandreas. (1999). "Residential environmental measurements in the
National Human Exposure Assessment Survey (NHEXAS) pilot study in Arizona: Preliminary
results for pesticides and VOCs." J. Exp. Anal. Environ. Epidemiol. 9:456-470.
Groot, M. E., M. C. Lekkerkerk, and L. P. A., Steenbekkers (1998). "Mouthing behavior of
young children: an observational study." Wageningen, The Netherlands: Agricultural University
Wageningen, Household and Consumer Studies.
Lewis, R. G., R. C. Fortmann, and D. E. Camann (1994). "Evaluation of methods for monitoring
the potential exposure of small children to pesticides in the residential environment." Arch.
Environ. Contain. Toxicol. 26: 37-46.
80
-------
Lewis, R. G. (2000). "Residential post-application pesticide exposure monitoring." in
Occupational and Incidental Residential Exposure Assessment, J.P Worgan and C.A. Franklin,
eds., John Wiley & Sons, Ltd., Sussex.
Lewis, R. G., C. R. Fortune, F. T. Blanchard, and D. E. Camann (2001). "Movement and
deposition of two organophosphorus pesticides within a residence after interior and exterior
applications," Air & Waste Manage. Assoc. 51:339-351.
Lioy, P. J., T. Wainman, and C. Weisel (1998). "A wipe sampler for the quantitative
measurement of dust on smooth surfaces: Laboratory performance studies," J. Exp. Anal.
Environ. Epidemiol. 3:315-330.
Lu, C. and R. A. Fenske (1999). "Dermal transfer of chlorpyrifos residues from residential
surfaces: comparison of hand press, hand drag, wipe, and polyurethane foam roller measurements
after broadcast and aerosol pesticide applications." Environ. Health Perspect. 107:463-467.
Mage, D. T. (1985). "Concepts of human exposure assessment for airborne paniculate matter."
Environ. Int. 11:407-412.
McCurdy, T. (1997). "Modeling the dose profile in human exposure assessments: ozone as an
example." Rev. Toxicol. 1:3-23
McCurdy, T. (2000). "Conceptual basis for multi-route intake dose modeling using an energy
expenditure approach." J. Expo. Anal. Environ. Epidemiol, 10:86-97.
McCurdy, T. (2001). "Research Note: Analyses to understand relationships among physiological
parameters in children and adolescents aged 6-16." Technical Paper, Office of Research and
Development, U.S. Environmental Protection Agency Research, Triangle Park, NC (under
review).
Melnyk, L. J., M. R. Berry, and L. S. Sheldon (1997). "Dietary exposure from pesticide
application on farms in the agricultural health pilot study." J. Exp. Anal. Environ. Epidemiol. 1
(1): 61-80.
Melnyk, L. J., M. R. Berry, L. S. Sheldon, N. C. G. Freeman, E. D. Pellizzari, and R. N. Kinman
(2000). "Dietary exposure of children hi lead-laden environments." J. Exp. Anal. Environ.
Epidemiol. 10(6, Part 2): 723 - 731.
Mihlan, G. J., L. A. Todd, and K. N. Truong (2000). "Assessment of occupational exposure
patterns by frequency-domain analysis of time series data." Appl. Occup. Environ. Hyg. 15:120-
130.
81
-------
Mukerjee D. (1998). "Assessment of risk from multimedia exposures of children to
environmental chemicals." J. Air Waste Manag. Assoc. 48:483-501.
NAS (1993). Pesticides in the Diets of Infants and Children. National Academy of Sciences,
National Academy Press, Washington, DC.
NIOSH (1994). NIOSHManual of Analytical Methods, 4th ed., U.S. Department of Health and
Human Services, Publ. 94-113 (August, 1994), Eller, P. & Cassinelli, M., eds. Washington, D.C.:
U.S. Government Printing Office, http://www.cdc.gov/niosh/nmam/nmampub.html
Nishioka, M. G., H. Burkholder, M. Brinkman, and R. G. Lewis (1999). "Distribution of 2,4-
dichlorophenoxyacetic acid in floor dust throughout homes following homeowner and
commercial lawn applications: quantitative effects of children, pets, and shoes." Environ. Sci.
Technol. 33:1359-1365.
OSHA (2000). OSHA Sampling and Analytical Methods, U.S. Department of Labor,
Occupational Health and Safety Administration.
http://www.osha-slc.gov/dts/sltc/methods/index.html
Quackenboss, J. J., E. D. Pellizzari, P. Shubat, R. W. Whitmore, J. L. Adgate, K. W. Thomas, N.
C. G. Freeman, C. Stroebel, P. J. Lioy, A. C. Clayton, and K. Sexton (2000). "Design strategy
for assessing multi-pathway exposure for children: the Minnesota Children's Pesticide Exposure
Study (MNCPES)." J. Expo. Anal. Environ. Epidemiol. 10(2): 145-158.
Rohrer, C. A., T. Hieber, L. J. Melnyk, and M. R. Berry (2001). "Transfer efficiencies of
pesticides from household surfaces to foods," In preparation.
Rosenblum, L., T. Hieber, and J. Morgan (2001). "Determination of pesticides in composite
dietary samples by gas chromatography/mass spectrometry in the selected ion monitoring mode
by using a temperature-programable large volume injector with preseparation column." JAOAC
International 84(3): 891 - 900.
Ross, J., T. Thongsinthusak, H. R. Fong, S. Margetich, and R. I. Krieger (1991). "Measuring
potential dermal transfer of surface pesticide residue generated from indoor fogger use: An
interim report." Chemosphere 20:349-360.
Thomas, K. W., L. S. Sheldon, E. D. Pellizzari, R. W. Handy, J. M. Roberds, and M. R. Berry
(1997). "Testing duplicate diet sample collection methods for measuring personal dietary
exposure to chemical contaminants." J. Expo. Anal. Environ. Epidemiol, 7(l):17-36.
Tomerlin, J. R., M. R. Berry, N. T. Tran, S. Chew, B. J. Petersen, K. D. Tucker, and K. H.
Fleming (1997). "Development of a dietary exposure potential model for evaluating dietary
82
-------
exposure to chemical residues in food" J. Expo. Anal. Environ. Epidemiol, 7(1):81-102.
U.S. EPA (1997a). Exposure Factors Handbook Vol I-III. National Center for Environmental
Assessment, Washington DC: U.S. Environmental Protection Agency (EPA/600/P-95/002Fa, b,
c).
U.S. EPA (1997b) Standard Operating Procedures (SOPs) For Residential Exposure
Assessment. Office of Pesticide Programs, U.S. Environmental Protection Agency, Washington,
D.C., Federal Register: September 7,1999 (Volume 64, Number 172), Notices, Page
48617-48618, March 1999. Washington, D.C., http://www.epa.gov/oppfeadl/trac/science/
U.S. EPA (1999a). Exposure Data Requirements for Assessing Risks from Pesticide Exposure of
Children. Office of Pesticide Programs, U.S. Environmental Protection Agency, Washington,
D.C., Federal Register: September 7,1999 (Volume 64, Number 172), Notices, Page
48617-48618, March 1999. http://www.epa.gov/oppfead 1 /trac/science/# 10-fold
U.S. EPA. (1999b). Compendium of Methods for the Determination of Toxic Organic
Compounds in Ambient Air - Second Edition, EPA/625/R-96/01 Ob, Center for Environmental
Research Information, http://www.epa.gov/ttn/amtic/airtox.html
U.S. EPA (2000a). Strategy for Research on Environmental Risks to Children. Office of
Research and Development, Washington, D.C. EPA/600/R-00/068, August, 2000.
http://www.epa.gov/ncea/risk2kids.htni
U.S. EPA (2000b). Summary Report of the Technical Workshop on Issues Associated with
Considering Developmental Changes in Behavior and Anatomy when Assessing Exposure to
Children. EPA/630/R-00/005, U.S. Environmental Protection Agency, Washington DC.
http ://www. epa. gov/ncea/raf/wrkshops .htm
U.S. EPA (2000c). Child-Specific Exposure Factors Handbook. NCEA-W-0853 June 2000
External Review Draft, U.S. Environmental Protection Agency, Washington DC.
http://www.epa.gov/ncea/csefh2.htm
U.S. EPA (2001) Manual of Analytical Methods for Determination of Selected Environmental
Contaminants in Composite Food Samples. EPA report (in preparation).
VaccaroJ. R., and R. J. Cranston (1990). "Evaluation of dislodgeable residues and absorbed
doses of chlorpyrifos following indoor broadcast applications of chlorpyrifos-based emulsifiable
concentrate." Dow Chemical Company, Midland, MI.
Van Wijnen, P. Clausing, B. Brunekreff (1990). "Estimating soil ingestion by children."
Environ. Res. 51:141-162.
83
-------
Whitmore, R. W., F. W. Immerman, D. E. Camann, A. E. Bond, R. G. Lewis, and J. L. Schaum.
(1994). "Non-occupational exposures to pesticides for residents of two U.S. cities." Arch.
Environ. Contam. Toxicol. 26: 47-59.
Wright,C. G., R. B. Leidy, and H. E. Dupree (1993). "Cypermethrin in the ambient air and on
surfaces in rooms treated for cockroaches." Bull. Environ. Contam. Toxicol. 51:356-360.
Zartarian V. G., H. Ozkaynak, J. M. Burke, M. J. Zufall, M. L. Rigas, and E. J. Furtaw Jr. (2000).
"A modeling framework for estimating children's residential exposure and dose to chlorpyrifos
via dermal residue contact and non-dietary ingestion," Environ. Health Perspect., 108(6):505-
514.
84
-------
APPENDIX A
Description of the ORD/NERL Stochastic Human Exposure and Dose
Simulation Model for Pesticides (SHEDS-Pesticides)
-------
The Stochastic Human Exposure and Dose Simulation model for pesticides (SHEDS-
Pesticides) developed by ORD/NERL is a probabilistic, physically-based model that simulates
aggregate exposures for population cohorts and multi-media pollutants of interest. SHEDS
simulates individuals from the user-specified population cohort by selecting daily sequential
time/location/activity diaries from surveys contained in EPA's Consolidated Human Activity
Database (e.g., the National Human Activity Pattern Survey). Depending on the type of pesticide
usage information entered, SHEDS can be used to simulate one day post-application exposures
from a single application event or daily, weekly, monthly, seasonal, or annual average exposures
from repeated pesticide applications over a year. It can also yield results for user residences only
or for the entire population of both user and non-user residences.
Exposure time profiles are the basis of the SHEDS exposure calculations. These are plots
of instantaneous exposure (mass, concentration, or mass loading at the external human boundary)
against time that preserve within-day peaks and variability as an individual moves throughout his
or her day. These exposure profiles can yield lexicologically relevant dose profiles, and
ultimately, improved risk estimates. They are constructed separately for each of the four
exposure routes included in SHEDS ~ inhalation, dietary ingestion, dermal contact, and non-
dietary ingestion (from hand-to-mouth and object-to-mouth pathways)-- and the time step is the
duration of the CHAD diary location-activity combinations. To generate a daily inhalation
exposure profile, SHEDS samples from indoor or outdoor air concentration distributions
corresponding to locations occupied by the sampled individual's diary. The air concentrations
are then combined with sampled values from activity-specific energy expenditure distributions
and basal metabolic rates for the diary-reported activities. Dermal exposure is modeled by
combining dermal transfer coefficient information with surface residues and time spent at and
near the applied surfaces. For bathing related locations and activities, a washing removal
efficiency is applied to the profile to simulate the reduced dermal loading. Non-dietary ingestion
exposure from hand-to-mouth and object-to-mouth transfer is simulated by combining dermal
hand loading or object residues with fraction of hands or objects inserted into the mouth,
frequency of mouthing activities, and saliva removal efficiency. Non-dietary ingestion via hand-
to-mouth contact is subtracted from the dermal exposure profiles. The dietary module in SHEDS
uses the latest USDA/EPA recipe files and 1994-1996,1998 Continuing Survey of Food Intakes
by Individuals (CSFII) consumption data, which includes about 10,000 food types and 21,660
person-days. CHAD individuals are matched with CSFII individuals, and for each CSFII person,
the reported consumption data are combined with sampled residue values in foods as eaten to
yield a modeled mass of residue ingested by meal. To obtain residue values in foods as eaten,
SHEDS applies the recipe files to the CSFII food types to break the food into raw agricultural
commodities (RACs), and then combines the RAC residues with use and processing factors.
To simulate one day post-application exposures for a population cohort, SHEDS samples
a single diary and combines the sequential location-activity durations with sampled values from
user-specified probability distributions for environmental media concentrations (either calculated
from user-specified application rates or sampled from user-specified distributions of measured
Al
-------
values) and exposure factors (e.g., saliva and washing removal efficiency, skin surface area
contacted, surface area of objects mouthed) into route-specific algorithms described above to
construct daily exposure time profiles. These exposure profiles can be combined with
pharmacokinetic models to yield route-specific dose profiles that can then be aggregated.
To simulate exposures from repeated applications over a year, SHEDS-Pesticides
simulates, for each individual in an age-gender cohort, 365 days by sampling 8 CHAD diaries
representing 1 person from each of 4 seasons and 1 person from each of 2 day categories
(weekend and weekday); fixing 5 weekday dairies and 2 weekend diaries; and then repeating the
7 day activity patterns within each season. It then sets days and times of pesticide applications
over the year based on user-specified probabilities for pesticide usage. Based on these
application times, environmental media residues and concentrations, either calculated from
application rates or sampled from user-specified distributions of measured values, are set every
day of the year for that individual. SHEDS then combines activities and residues with sampled
values from probability distributions for exposure factors to generate longitudinal 1-year
exposure profiles that can be entered as inputs to pharmacokinetic models to simulate the
corresponding route-specific dose profiles. Once the dose profiles are obtained, they can be
summed across routes to yield an individual's aggregate dose profile for the chemical of interest.
Once the exposure and dose profiles are generated for each individual, the metrics of
interest (e.g., peak, time-averaged, time-integrated) are extracted from the individual's profiles,
and the process is repeated thousands of times to obtain population distributions. This approach
allows identification of the relative importance of routes, pathways, and model inputs. Sensitivity
analyses are conducted using stepwise regression and correlation methods to identify the relative
importance of routes and model inputs. If the user enters uncertainty distributions associated
with model inputs, SHEDS applies two-stage Monte-Carlo simulation to derive estimates of
inter-individual variability in the population and uncertainty in estimated empirical exposure and
dose distributions.
A2
-------
APPENDIX B
Examples of a Food Diary and a Hygiene and Dietary Habit Survey
Used in Recent NERL Pilot Studies
-------
HOW TO COLLECT FOODS AND BEVERAGES
WHERE WE WANT YOU TO COLLECT FOOD
1) Please collect only foods and beverages that are eaten at home, or are prepared at home
but are eaten elsewhere.
WHAT WE WANT YOU TO COLLECT
1) Please prepare and collect a second portion (as close as possible to the exact amount) of
every food or beverage your child eats at every meal, snack, or any other time on the
collection days.
2) This does not include vitamins, medicines, chewing gum, toothpaste, or any other non-
edible item.
3) Please collect a sample of any foods that your child has dropped on the floor. You should
collect only those foods from the floor that your child is likely to eat after they have
dropped on the floor.
4) Please have your child eat the same foods he/she would have eaten if we were not here.
WHEN WE WANT YOU TO COLLECT THE FOOD
1) Please collect the foods and beverages eaten from midnight to midnight on
HOW TO COLLECT THE DUPLICATE-DIET SAMPLE
1) At every meal or snack, prepare a second plate with the same type and amounts of food
you have prepared for your child. Include all spices, sauces, butter, salt, ketchup, etc.
Prepare a second cup, glass, or other container with the same amount of beverage that the
child will drink. If you can, please use the same kind of plates, cups, and glasses for the
food collection as used for the meal.
2) If you give your child more servings of food or beverage during the meal, add the same
amount to the second plate, cup, or glass. Use more plates, cups, or glasses if necessary.
3) At the end of the child's meal, remove from the second plate, cup or glass the same
amount of food as was left on your child's plate, glass or cup. If you are able, remove any
inedible portions, like bones or pits, from foods on the second plate. The food or
beverage that is now on the second plate or in the second cup should be the same amount
that your child ate or drank.
5) We have given you four zip-lock bags: one marked breakfast, one marked lunch, one
marked dinner, and one marked snacks. Transfer the food on the second plate (not your
Bl
-------
child's plate) to a zip-lock bag for the meal that was just eaten. Seal the bag. Place the
bag in your refrigerator if it contains foods that could spoil.
6) Add all beverages from the second cup (not your child's cup) to the plastic bottle. Frozen
items that could melt, like ice cream or popsicles, should also be put into the plastic bottle
with the beverage samples not with the food samples.
7) Close the jar lid and put the jar in your refrigerator.
HOW TO USE THE 24-HOUR FOOD DIARY
INSTRUCTIONS
(1) We want you to list all of the foods, beverages, or drinking water that your child
eats or drinks from midnight to midnight.
(2) Every time your child eats, write down the name of the meal (breakfast, lunch,
dinner, snack).
(3) Then write down on a separate line the name of every food or beverage that your
child eats or drinks.
(4) For food mixtures such as stews or potpies, please write down the major kinds of
foods in the mixture. Use the lines immediately below the one on which the name
of the mixture is entered.
(5) For beverages (including water), write down how many cups or glasses that your
child drink(s).
(6) When we collect the food samples, we will ask you several questions about each
food that your child ate. These will include:
(a) In the last month, how often did your child eat this food each week?
(b) Where was the food that you collected eaten?
(c) Did any of the food eaten have contact with your child's hands, the floor, or
other surfaces?
(d) Were foods cooked in or prepared with tap water?
(e) Were beverages cooked in or prepared with tap water?
B2
-------
FOOD DIARY
START DATE: TIME:
END DATE: TIME:
Meal
Lunch
PLEASE LIST ALL FOODS, BEVERAGES, THAT YOUR
CHILD EAT(S) OR DRINK(S) AND HOW MANY OF EACH
ITEM
EXAMPLE: CHEESEBURGER
EXAMPLE: SALAD WITH LETTUCE AND TOMATOES
EXAMPLE: WATER
How
Many
1
1
2
glasses
FOR INTERVIEWER USE ONLY
Portion
Size
Frequenc
y
Eaten
Where
Eaten
Contact With
Fingers
Floors
Other
Surfaces
Food
Tap
Water
Beverage
s
Tap
Water
W
U)
-------
FOOD DIARY - SUPPLEMENTARY QUESTIONS
COMPLETE ON SAME DAYS FOOD IS DAY:
RECORDED IN DIARY AND SAMPLES DATE:
COLLECTED
1 . Please think back, were there any foods or beverages that
you could not or did not collect for use: (LIST
IDENTITY, SOURCE, AND AMOUNT OF EACH
MISSING FOOD AND THE DAY IT WAS NOT
COLLECTED.)
a. At Breakfast
b. At Lunch
c. At Dinner
d. For Snacks
1
/ /
YN
YN
YN
YN
2
/ /
YN
YN
YN
YN
3
/ /
YN
YN
YN
YN
B4
-------
COMPLETE ON SAME DAYS FOOD IS DAY:
RECORDED IN DIARY AND SAMPLES DATE:
COLLECTED
2a. Did (your child), for any reason, eat more or less food
than usual? (READ CHOICES AND ENTER a OR b).
a. More food than usual -* GO TO 2b.
b. Less food than usual -» GO TO 2b.
c. Same as usual -4 GO TO 3 .
2b. Because of: (READ CHOICES AND CIRCLE ALL
THAT APPLY.)
a. Travel or vacation
b. Weight control diet
c. Illness or medical condition
d. Work or school schedule
e. Entertainment or social occasion
f. Because of the food collection study
g. Other (Specify dav):
3 a. Did (your child), for any reason, eat different foods than
(your/his/her) usual diet? (CIRCLE Y FOR YES AND N
FOR NO.)
3b. If yes, was that because: (READ CHOICES AND
CIRCLE ALL THAT APPLY.)
a. Travel or vacation
b. Weight control diet
c. Illness or medical condition
d. Work or school schedule
e. Entertainment or social occasion
f. Because of the food collection study
e. Other f Specify dav):
1
/ /
a
b
c
d
e
f
g
YN
a
b
c
d
e
f
g
2
/ /
a
b
c
d
e
f
g
YN
a
b
c
d
e
f
g
3
/ /
a
b
c
d
e
f
g
YN
a
b
c
d
e
f
g
B5
-------
COMPLETE ON SAME DAYS FOOD IS DAY:
RECORDED IN DIARY AND SAMPLES DATE:
COLLECTED
4a. List all of the floor foods collected.
4b. Where were floor foods collected from?
1
2
3
B6
-------
Hygiene and Dietary Habit Survey
Parent's name: Child's name:
How old is your child? DOB: .
How much does your child weigh (use a scale ?)
We want to ask some questions about (name of
child). We are interested in the foods your child eats, and how the food is stored and prepared.
We want to find out if these things influence your child's lead exposure.
Part 1. We now have some questions about your child's eating habits.
1. Does your child eat food with his/her fingers? What types?
1. Yes 1. Often
2. No 2. Sometimes
9. Unknown 3. Almost never
9. Unknown
2. Where does your child usually eat his/her meals when at home?
1. Kitchen 1. At table
2. Living room 2. High chair
3. Bedroom 3. Chair or couch
4. Dining room 4. Sitting on the floor
5. Other 5. Other
9. Unknown 9. Unknown
3. Where does your child usually eat his/her snacks?
1. Kitchen 1. At table
2. Living room 2. High chair
3. Bedroom 3. Chair or couch
4. Dining room 4. Sitting on the floor
5. Other 5. Other
9. Unknown 9. Unknown
B7
-------
4. What snacks does your child usually eat at home?
1.
2.
3.
4.
5.
5. How frequently does your child eat food off of the floor?
1. Often 2. Sometimes 3. Almost never
9. Unknown
6. Does your child ever prepare or get his/her own food?
(for instance peel a banana, get a bowl of cereal, finger foods)
What foods?
1. Yes 1. Often
2. No 2. Sometimes
9. Unknown 3. Almost never
9. Unknown
7. Does an older brother or sister ever prepare or get your child's food?
(For instance peel a banana, get a bowl of cereal, finger foods)
What foods?
1. Yes 1. Often
2. No 2. Sometimes
9. Not applicable 3. Almost never
9. Unknown
8. Does your child ever eat food after it has dropped on the floor?
What foods?
1. Yes 1. Often
2. No 2. Sometimes
9. Not applicable 3. Almost never
9. Unknown
B8
-------
9. Does your child drink from bottles?
1. Yes
2. No
9. Not applicable
10. Do you have a cat in the home?
1. Often
2. Sometimes
3. Almost never
9. Unknown
1. Yes a. Does your child play with it before meals?
2. No
b. Does your child play with it during meals?
11. Do you have a dog in the home?
1. Yes
2. No
a. Does your child play with it before meals?
b. Does your child play with it during meals?
1. Yes
2. No
9. Unknown
1. Yes
2. No
9. Unknown
1. Yes
2. No
9. Unknown
1. Yes
2. No
9. Unknown
12. Has your child eaten outside in the past 3 months?
1. Yes
2. No
9. Unknown
how often?
1. >3 times/week
where? (all that apply)
1. backyard at home
2. about l/week(go to 13) 2. yard at friend's or neighbors
3.
-------
6. stroller
7. other
9. unknown
9. unknown
13. a. How many times does your child wash his/her hands each day? _
b. When does your child wash his/her hands? (check all that apply)
1. before meals
2. after meals
3. before snacks
4. after snacks
5. after going to the bathroom
6. before going to bed
7. after coming in doors
8. other
Part 2. We would now like you to tell us about some of vour activities.
14. Where do you keep:
a. fresh fruits
1. on counter/table
2. in cabinet
3. in refrigerator
4. other
5. don't usually have
15. In what containers do you store
Raw fruits?
Covered?
Raw vegetables?
Covered?
16. In what containers do you store
Cereals?
Covered?
Pastas?
Covered?
17. In what containers do you store meats? Covered?
b. fresh vegetables
1. on counter/table
2. in cabinet
3. in refrigerator
4. other
5. don't usually have
BIO
-------
18. Where do you prepare foods? (check all that apply)
1. kitchen counter
2. kitchen table
3. kitchen sink
4. chopping board
5. other
yes
yes
yes
yes
no
no
no
no
19. Do you wash your hands before preparing the food?
1. yes
2. no
20. Do you wash your hands before
1. yes
2. no
1. always
2. usually
3. sometimes
4. seldom
serving the food?
1. always
2. usually
3. sometimes
4. seldom
21. Do you wash the food preparation surface....
a. before food preparation b. after food preparation
1. yes 1. yes
2. no 2. no
22. How do you wash plates and glasses?
23. How do you dry plates and glasses?
1. by hand
2. dishwasher
3. use throw aways/paper plates
4. other
1. air dry
2. cloth towel
3. paper towel
4. dishwasher
5. other
Bll
-------
24. What type of cookware (pots and pans) do you use? (check all that apply)
1. stainless
2. aluminum
3. cast iron
4. glass
5. ceramic/pottery
6. plastic
7. other
25. How do you wash cookware and utensils?
1. by hand
2. dishwasher
3. other
26. How do you dry cookware and utensils?
27. If you use cloth dish towels
How often are they washed
1. as needed
2. more than once a week
3. once a week
4. less than once a week
9. don't know
1. air dry
2. cloth (dish) towel
3. paper towel
4. dishwasher
5. other
Are they also used as
1. hand towels
2. face towels
3. to dry counters
4. other
9. don't know
Answer by Observation
1. Cleanliness of house
1. clean
3. dirty
2. Cleanliness of child
1. clean
3. dirty
2. somewhat clean
2. somewhat clean
B12
-------
3. Does the child fist his/her food when handling/eating?
1. yes
2. no
Thank you for your help. Do you have any questions at this time?
B13
------- |