vxEPA
United States
Environmental Protection
Agency
Important Exposure Factors
for Children
An Analysis of Laboratory and
Observational Field Data Characterizing
Cumulative Exposure to Pesticides
RESEARCH AND DEVELOPMENT
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EPA600/R-07/013
March 2007
Important Exposure Factors
for Children
An Analysis of Laboratory and Observational
Field Data Characterizing Cumulative
Exposure to Pesticides
By
Peter P. Egeghy1, Linda S. Sheldon1, Roy C. Fortmann1, Daniel M. Stout II1, Nicolle S. Tulve1, Elaine Cohen
Hubal2, Lisa J. Melnyk3, Marsha Morgan1, Paul A. Jones1, Donald A. Whitaker1, Carry W. Croghan1, April Coan1
1US EPA, Office of Research and Development, National Exposure Research Laboratory, Human Exposure and
Atmospheric Sciences Division, Research Triangle Park, NC 27711
2US EPA, Office of Research and Development, National Center for Computational Toxicology, Research
Triangle Park, NC 27711
pment, National Exposure
Chemical Exposure Assessment Research Division, Cincinnati, OH 45268
3US EPA, Office of Research and Development, National Exposure Research Laboratory, Microbiological and
National Exposure Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Research Triangle Park, NC, 27711
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Notice
The U.S. Environmental Protection Agency, through its Office of Research and Development, funded and
managed or partially funded and collaborated in the research described in this report. 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.
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Abstract
In an effort to facilitate more realistic risk assessments that take into account unique childhood
vulnerabilities to environmental toxicants, the U.S. EPA's National Exposure Research
Laboratory (NERL) developed a framework for systematically identifying and addressing the
most important sources, routes, and pathways of children's exposure to pesticides. Four priority
research areas were identified as representing critical data gaps in our understanding of
environmental risks to children. Several targeted studies were conducted under NERL's
children's exposure research program to specifically address these priority research needs. This
document is a comprehensive summary report of data collected in these studies to address the
priority research needs and is intended for an audience of exposure scientists, exposure modelers,
and risk assessors. The parameters measured and the measurement methods are described. Data
on representative organophosphate and pyrethroid pesticides are compared across studies and
across compounds with the primary purpose of identifying or evaluating important factors
influencing exposures along each relevant pathway. Summary statistics, comparative analyses,
and spatial and temporal patterns are presented to address previously identified data gaps.
Results are compared across studies in order to identify trends that might provide a better
understanding of the factors affecting children's exposures. While highlights of the results of
individual studies are presented, the focus is on presenting insights gleaned from the analysis of
the aggregated data from several studies. By examining relationships among application
patterns, exposures, and biomarkers for multiple compounds from different classes of pesticides,
this report strives to help produce more reliable approaches for assessing cumulative exposure.
in
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Executive Summary
In an effort to facilitate more realistic risk assessments that take into account unique childhood
vulnerabilities to environmental toxicants, the National Exposure Research Laboratory (NERL)
in the U.S. Environmental Protection Agency's (U.S. EPA) Office of Research and Development
(ORD) developed a framework for systematically identifying and addressing the most important
sources, routes, and pathways of children's exposure to pesticides (Cohen Hubal et al, 2000a,
2000b). Using this framework, a screening-level assessment was performed to identify the
exposure pathways with the greatest potential exposures. The uncertainty associated with
assessing exposure along each pathway was then evaluated through an exhaustive review of
available data. Four priority research areas were identified as representing critical data gaps in
our understanding of environmental risks to children. The absence of sufficient real-world data
in all four of these areas produces an excessive reliance on default assumptions when assessing
exposure. These priority research areas are: 1) pesticide use patterns; 2) spatial and temporal
distributions of residues in residential dwellings; 3) dermal absorption and indirect (non-dietary)
ingestion; and 4) dietary ingestion.
Several targeted studies were conducted or financially supported by NERL under the children's
exposure research program to specifically address these priority research needs. These studies
included:
Children's Total Exposure to Persistent Pesticides and Other Persistent Organic
Pollutants ("CTEPP")
First National Environmental Health Survey of Child Care Centers ("CCC")
Biological and Environmental Monitoring for Organophosphate and Pyrethroid Pesticide
Exposures in Children Living in Jacksonville, Florida ("TAX")
Center for the Health Assessment of Mothers and Children of Salinas Quantitative
Exposure Assessment Study ("CHAMACOS")
Children's Pesticide Post-Application Exposure Study ("CPPAES")
Distribution of Chlorpyrifos Following a Crack and Crevice Type Application in the US
EPA Indoor Air Quality Test Research House ("Test House")
Pilot Study Examining Translocation Pathways Following a Granular Application of
Diazinon to Residential Lawns ("PET")
Dietary Intake of Young Children ("DIYC")
Characterizing Pesticide Residue Transfer Efficiencies ("Transfer")
Food Transfer Studies ("Food")
Feasibility of Macroactivity Approach to Assess Dermal Exposure ("Daycare")
Two studies performed prior to the identification of priority research areas also provided useful
data. These were:
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National Human Exposure Assessment Survey in Arizona (NHEXAS-AZ)
Minnesota Children's Pesticide Exposure Study ("MNCPES")
All studies involving children were observational research studies, as defined in 40 CFR Part
26.402. All study protocols and procedures to obtain the assent of the children and informed
consent of their parents or guardians were reviewed and approved by an independent institutional
review board (1KB) and complied with all applicable requirements of the Common Rule
regarding additional protections for children. Further, all protocols regarding recruitment and
treatment of participants were reviewed by the EPA Human Subjects Research Review Official
(HSRRO) to assure compliance with the Federal Policy for the Protection of Human Subjects.
The studies took place in EPA research laboratories, in the EPA Indoor Air Quality Research
Test House, in private residences, and in child care centers. The studies have been grouped as
a) large observational field studies (NHEXAS-AZ, MNCPES, CTEPP, and CCC), b) small pilot-
scale observational studies (JAX, CPPAES, DIYC, CHAMACOS, and Daycare), and
c) laboratory studies (Test House, Transfer, and Food). The large observational field studies had
either a regional (NHEXAS-AZ, MNCPES, CTEPP) or national (CCC) focus. A broad suite of
chemical contaminants, including organophosphate and pyrethroid pesticides and their metab-
olites, were typically measured in multiple environmental media and in urine. Some of the small
pilot-scale studies included measurements of multiple chemicals in multiple media in locations
either with year-round residential pesticide use (JAX) or in close proximity to agricultural fields
(CHAMACOS). Other pilot-scale studies focused on a single compound (CPPAES, DIYC, PET,
Daycare). The laboratory studies (Transfer, Food, Test House) evaluated factors affecting
transfer from surfaces or investigated post-application spatial and temporal variability. One of
the primary objectives for all of these studies was to determine and quantify the key factors that
influence exposure along the pathways relevant to the four priority research areas.
This document is a comprehensive summary report of data collected under the NERL children's
exposure research program and is intended for an audience of exposure scientists, exposure
modelers, and risk assessors. The parameters measured and the measurement methods are
described. Data on representative organophosphate and pyrethroid pesticides are compared
across studies and across compounds with the primary purpose of identifying or evaluating
important factors influencing exposures along each relevant pathway. Summary statistics,
comparative analyses, and spatial and temporal patterns are presented to address previously
identified data gaps. Results are compared across studies in order to identify trends that might
provide a better understanding of the factors affecting children's exposures. While highlights of
the results of individual studies are presented, the focus is on presenting insights gleaned from
the analysis of the aggregated data from several studies. By examining relationships among
application patterns, exposures, and biomarkers for multiple compounds from different classes of
pesticides, this report strives to help produce more reliable approaches for assessing cumulative
exposure.
With limited data available to EPA researchers on the types, locations, and frequency of
pesticide usage in residential and other non-occupational environments, pesticide use patterns
were identified as a priority research area. Accordingly, pesticide use information was collected
by inventory and questionnaire in each of the field studies. Questionnaire items and inventory
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forms differed, geographic regions represented were limited, and the total number of study
participants was relatively small. Furthermore, during the period of four years covered (1997 to
2001), pesticide manufacturers were increasingly replacing organophosphates with pyrethroids in
their formulations, and restrictions on residential applications of the most commonly used
organophosphates were approaching. Nevertheless, important usage information was produced
by the studies. Pyrethrins and their synthetic analogs (pyrethroids), specifically permethrin,
cypermethrin, and allethrin, are clearly the most frequently used insecticides for indoor appli-
cations in homes and child care centers based on inventories and records. Organophosphates
appear to persist in indoor environments, as chlorpyrifos and diazinon were more frequently
detected in screening wipes (at frequencies comparable to permethrin) than in inventories.
Among the carbamates, only propoxur and carbaryl were inventoried or reportedly used.
"Crack-and-crevice" type applications were used more often than either broadcast or total release
aerosol ("fogger") applications. Applications were more likely to be performed by the resident
than by a professional service in JAX, and also as reported in NHANES. In JAX, the modes of
application included hand pump sprayer (37%), aerosol can (24%), fogger (3%), and baits (3%),
but the pertinence of these results to other locations is unknown. Apart from these results,
information on application type and method was not collected.
Pesticide products were found in at least 86% of JAX and MNCPES screening households, with
a mean of three products per household. There is evidence in support of a pattern of higher
application frequencies in warmer climates, with the percentage of participants reporting use in a
given time period highest in Florida, lower in North Carolina and Ohio, and lowest in Minnesota.
The percentage in Jacksonville, FL is substantially higher, and the percentage in Minnesota is
substantially lower, than the national average reported in NHANES. In childcare centers,
monthly interior pesticide applications were performed in about a third of the CCC facilities
nationwide and were anecdotally found to be standard practice among daycares contacted in
North Carolina.
There were no statistically significant differences in the total number of products found or
reportedly used in MNCPES based on either population density (urban vs. non-urban
households) or other socio-demographic factors including race, ethnicity, home type, income,
and level of education. Similarly, analysis of CTEPP data found no association between
application frequency and either population density or income class.
A second primary research area is spatial and temporal distributions of pesticides in residential
dwellings. Spatial and temporal heterogeneity may affect exposure estimates along all exposure
routes. Absorption via the inhalation route relies on the measured airborne concentration.
Absorption via the dermal and indirect ingestion routes relies on the measured surface loading.
Even estimates of dietary ingestion for children may depend on surface concentrations due to
pesticide transfer during food preparation and handling. Examination of distribution patterns of
airborne and surface residues has yielded important insights.
The organophosphate insecticides chlorpyrifos and diazinon were most frequently detected in
both indoor air and outdoor air in these field studies, but the detection frequencies in outdoor air
were lower and more variable across studies. Chlorpyrifos was frequently detected even after its
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indoor residential use was restricted, perhaps due to emissions from indoor sinks (e.g., carpets)
and from continued use of existing home inventories. Indoor air concentrations were typically
an order of magnitude higher than outdoor air concentrations, with notable exceptions of outdoor
diazinon and permethrin levels which were nearly as high as indoor levels in JAX, and outdoor
diazinon levels that exceeded indoor levels in the agricultural community monitored in
CHAMACOS. The low pesticide concentrations routinely measured outdoors (notwithstanding
the exceptions noted) together with the relatively short time spent outdoors suggests that
inhalation of outdoor air is not typically an important contributor to aggregate pesticide
exposure. The similarity across large observational field studies in the variability of the
observed indoor air chlorpyrifos concentrations, despite sample collection periods ranging from
1 to 7 days, suggests that air concentrations are reasonably consistent from day-to-day in the
absence of a recent application.
The median indoor air concentrations of the organophosphates are higher than that of the
pyrethroids. While these studies were conducted at a time when organophosphates arguably
dominated the marketplace, a comparison of the mean levels of various organochlorine,
organophosphate, and pyrethroid pesticides measured in CTEPP finds that the concentrations
measured in the absence of recent applications appear to be strongly influenced by vapor
pressure, with the more volatile pesticides, such as chlorpyrifos, found at the highest levels.
Consequently, the importance of inhalation as a route of exposure for pesticides is likely to
decrease as less volatile pesticides, such as the pyrethroids, are introduced into the market.
Differences in sampling methods, year of the study, and time of year when samples were
collected make it difficult to distinguish any regional differences in pesticide concentrations. In
general, median indoor air concentrations were somewhat higher in southern states (NHEXAS-
AZ and CTEPP-NC) than in northern states (MNCPES and CTEPP-OH). However, the
distributions exhibit considerable overlap across geographical locations. When daycare
measurements are included, a geographical difference is less obvious, perhaps due to regular,
calendar-based pesticide treatments at many daycare facilities.
Irrespective of region, differences in indoor air levels between homes and daycares were not
found to be statistically significant. Similar mean indoor air levels observed in homes and
daycares demonstrate the potential for continued exposure as a child spends time in other indoor
locations. Additional concentration measurements in other locations would be useful to examine
exposure potential from different settings such as schools, restaurants, and other public and
private locations where pesticides are also applied.
Differences in indoor air concentrations associated with population density and income level
were observed in the field studies. Differences between urban and rural air concentrations were
observed in both MNCPES and CTEPP. In fact, urban chlorpyrifos levels were about 25%
higher than rural levels across studies. A reasonable explanation may be that urban areas require
more intensive use of pesticide products to control a range of pests over a wider seasonal span.
Concentrations of chlorpyrifos and diazinon were higher in low-income homes than in
medium/high income homes in CTEPP, but the difference was statistically significant only for
diazinon, and only in NC.
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Within-home spatial and temporal patterns were investigated following a crack and crevice
application of chlorpyrifos in the kitchen of the Test House. The pesticide was detected even in
the farthest bedroom from the application, with a concentration gradient observed from the
kitchen to the den (proximal area) to the master bedroom (distal area). Temporally, airborne
concentrations peaked on day 1, then decreased by approximately 80%, but were still
measurable, at 21 days after application. In contrast, airborne diazinon concentrations among
homes in the DIYC study were most pronounced 4-5 days after application. Between-home
spatial variability following a pesticide application was investigated in the CPPAES study.
Indoor air chlorpyrifos concentrations spanned more than an order of magnitude among the
homes one day after application.
Significant progress has also been made in understanding spatial and temporal distributions of
organophosphate residues on surfaces. In a published analysis of the MNCPES surface wipe
data, Lioy and colleagues (2000) reported substantial variability in surface chlorpyrifos levels
among different rooms. Substantial variability among and within rooms is also evident in the
Daycare data. Furthermore, data from the Test House also show that surface loadings cannot be
assumed to be homogenous even within a room. These observations suggest that multiple
locations should be sampled to more accurately represent surface loadings. Exposure modelers
using probabilistic methods have already begun to account for differences in surface loadings
based on proximity to application sites in order to reduce possible exposure misclassification in
their exposure estimates.
A number of observations suggest that there is substantial translocation of pesticides from
application surfaces to adjacent surfaces, but levels remain higher at the application location. In
CPPAES, the post-application chlorpyrifos loadings were higher than the pre-application values
even on surfaces that did not receive a direct application. In DIYC, the transferable residues on
the counters were nearly as high as those on the floors immediately after application. In JAX,
the application area surface residue loadings were generally higher than the play area surface
residue concentrations. In the CCC, the floor residue loadings were generally higher than the
desk top loadings. High loadings of diazinon in indoor house dust following the lawn treatment
in the PET study suggest that transfer into the house may also occur.
Examination of chlorpyrifos and diazinon loadings following applications indicates that total
available residue loadings decay at a slower rate than airborne concentrations. Total available
residue loadings (obtained by methods intended to measure the total amount of contaminant on a
surface) also appear to decline at a slower rate than transferable residue loadings (intended to
represent the amount that is transferred as a result of contact with the contaminated surface). In
fact, using a total available residue method, chlorpyrifos was measured in 62% of the MNCPES
samples, even in the absence of a recent pesticide application.
On a regional level, Jacksonville, Florida, an area known for year-round pest control issues and
identified as having high pesticide usage during the NOPES study (Whitmore et al, 1994), had
much higher surface concentrations than any of the other studies without recent applications.
Within a given region, however, there appears to be little relationship between questionnaire
information and measured surface values. Previously published results from the MNCPES
indicate that the residential pesticide use questions and overall screening approach used in the
MNCPES were ineffective for identifying households with higher levels of individual target
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pesticides (Sexton et al, 2003). Results from the CPPAES study suggest that cleaning activities
and ventilation influence surface concentrations; it appears that the surface chlorpyrifos loadings
were lower in those homes in which the occupants reported additional cleaning activities and/or
high ventilation rates.
While significant progress has been made in understanding spatial distributions of organo-
phosphate and pyrethroid pesticides in the absence of a recent application and in understanding
spatial and temporal distributions of organophosphate pesticides following an application, no
data have been produced on the spatial and temporal distributions of pyrethroids following
applications. The movement of residentially applied insecticides follows a complex and poorly
understood process of transformation and phase distribution and is influenced by several factors.
Differences in physicochemical characteristics make it difficult to generalize the spatial and
temporal distributions of organophosphate pesticides to pyrethroid pesticides, but with
information on chemical properties and on human activities, distribution patterns can be
modeled.
The third primary research area was identified as dermal absorption and indirect ingestion.
Intake via these exposure routes is often estimated using measurements of pesticide
concentrations in dust and soil and pesticide loadings on surfaces. Intake estimates also rely on
numerous default exposure factor assumptions. Pesticides in dust generally had high detection
frequencies, consistent with dust being considered a repository of contaminants. Detection
frequencies for soil samples, on the other hand, were generally low (with the exception of
measurements made immediately following lawn applications).
Compounds found at relatively higher concentrations in dust tend to be found at relatively lower
concentrations in air. The less volatile pyrethroid pesticides tend to partition to the dust and may
degrade more slowly allowing accumulation over time from repeated applications. This
underscores the importance of dust as a primary residential exposure medium for the less volatile
pesticides. In addition, the exposure factors that are important for other nonvolatile
contaminants such as lead may also be important for the less volatile pesticides.
Pyrethroids generally have low vapor pressures and Henry's Law constants, thus they are poorly
volatilized and exist almost entirely in the particulate phase at room temperature. Furthermore,
high octanol/water (Kow) and water/organic carbon (Koc) partition coefficients cause pyrethroids
to partition into lipids and into organic matter. With these characteristics, pyrethroids can be
expected to bind readily to the particulate matter that comprises house dust. Particles
resuspended by human activity then act as the primary vector for pyrethroid transport and for
human exposure. Particle-bound movement and transfer of pyrethroids imply a decreased
importance of the inhalation route and an increased importance of routes that involve dermal
transfer, such as indirect ingestion and dermal absorption. Exposure of young children, for
whom indirect ingestion of residues from object- and hand-to-mouth activities is particularly
important, may be most strongly affected. In fact, algorithm-based estimates of distributions of
intake of chlorpyrifos and permethrin from the four contributing routes among the CTEPP-OH
children indicated that the contribution from the indirect route is much more important for
permethrin than for chlorpyrifos.
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Comparisons of pesticide surface loadings (ng/cm2) showed higher levels in the CTEPP day care
centers than in the homes. This appears to be the result of higher amounts of dust in the daycare
centers, as there is not as large of a difference in the pesticide concentrations (ng/g) in the dust.
Studies with lead have suggested that loading may have a greater impact than concentration on
actual intake, thus higher amounts of dust may be important even if the concentration within the
dust is similar.
Data from our studies show that the collection methods utilized may have sizeable effects on
estimates of dermal exposure and indirect ingestion. Total residue methods, which use both
solvent and mechanical action to remove residues that may have penetrated into the surface,
produce the highest values, followed by dust methods, and then by transferable residue methods.
These methods are intended to measures different types of transfer, and efficiencies for various
methods have been previously published. Use of total residue methods allows the assessor to use
appropriate transfer factors to represent a transfer efficiency applicable to a given scenario.
Questions remain, however, on exactly how much of what is measured by total residue methods
is truly available for transfer and how much would otherwise be trapped in the pores and/or body
material of the surfaces if not for the mechanical and solvent action of the methods.
Even the amount of solvent used with wipe samples affects the results. The low pesticide
surface loadings obtained with 2 mL isopropyl alcohol wipes in both the NC and OH CTEPP
studies (loadings similar to those obtained with the polyurethane foam [PUF] roller) suggest that
the amount of IP A applied to the wipe may affect the amount of pesticide residue recovered.
Surface type has also been shown to affect the collection efficiency of wipes. Recently
published NERL data (Rohrer et al, 2003) found that with respect to pesticide transfer, wiping
from hard surfaces greatly exceeded carpet, and wiping from tile generally exceeded hardwood.
Clearly, some standardization of surface sampling methods is needed.
Although successfully used in laboratory studies, the Modified CIS Surface Press Sampler was
rarely able to measure pesticide residues in field studies. The original press sampler was
designed to measure transfer of dust-bound pesticides to the skin from a single hand press onto a
carpeted surface. The uses for the modified CIS surface press sampler have expanded to include
hard surfaces and longer contact times, effectively using the press sampler in a manner for which
it was not intended. Our data suggest that the sensitivity of the modified CIS surface press
sampler may be too low to measure residential pesticide residues (which may transfer by both
equilibrium mass transfer and mechanical transfer).
Laboratory studies using fluorescent tracers (as surrogates for pesticide residues) indicated that
tracer type, surface type, contact motion, and skin condition were all significant factors.
Transfer was greater with laminate (over carpet), smudge (over press), and sticky skin (over
moist or dry). Contact duration andpressure (force) were not found to be important factors.
The effect of surface type appeared to diminish with repeated contact, while the effect of skin
condition (moist vs. dry) appeared to increase with repeated contact. Additional studies are still
needed to gain a better understanding of the key factors that influence the dermal transfer and
indirect ingestion of pesticides.
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The frequencies of hand- and object-to-mouth contacts were quantified for preschool children in
the CTEPP and CPPEAS studies using the Virtual Timing Device (VTD) software (Zartarian et
al.. 1997). The CPPAES results support the use of the commonly assumed median count of 9.5
hand-to-mouth contacts per hour; however CTEPP data suggest a much higher value for younger
children. The CTEPP methodology also accounts for combination hand- and object-to-mouth
contacts during both eating and non-eating events.
The fourth primary research area was identified as dietary ingestion. Diet can be an important
pathway of exposure. Foods may contain residues of pesticides and other environmental
chemicals because of intentional applications or may become contaminated during processing,
distribution, storage, and consumption. For certain chemicals, diet is potentially the predominant
pathway of exposure. Children's dietary exposure to pesticides is not limited to the residues in
or on foods when they are brought into the home. Children's unique handling of foods prior to
consumption requires special attention, but it is rarely considered in study designs.
Based on route-specific intake estimates, dietary ingestion represented the dominant route of
exposure for chlorpyrifos, diazinon, and permethrin in the CTEPP study. Unfortunately, the
route that represented the dominant route of exposure was also the route with the lowest
detection frequencies (approximately 2/3 of the values for permethrin in CTEPP were
nondetects), which increases the uncertainty in the estimates. Substituting a fraction of the
detection limit for values below the limit of detection may have a disproportionate impact on
assessing the importance of the dietary route.
The most common measure of dietary exposure was by composited duplicate diet analyses.
However, great care must be taken to ensure that the duplicate diet accurately reflects what is
actually consumed instead of what is served because significant quantities of food may remain
uneaten by children. Duplicate diets fail to capture those pesticide residues transferred to foods
as a result of the child's handling of food prior to and during consumption. In DIYC, estimates
of dietary intake that included excess contamination due to handling were as much as double the
estimates of intake based on duplicate diet alone. These results suggest that dietary estimates
based on duplicate diet may not be as reliable for young children as they are for adults.
Progress has been made in many areas and we are beginning to understand the environment that
children live in, their activities, and the resulting exposures. However, research is still needed to
adequately characterize the magnitude, routes and pathways of exposure. We still need to
understand the key factors that influence the dermal transfer and indirect ingestion of pesticides.
We need to be able to more accurately assess dietary exposure. In order to evaluate exposure
models, we must be able to quantify the relationships between and among environmental
concentrations of pesticides in various media, children's activities, and the results of biomarkers
of exposures as measured in urine and/or blood. Exposure models outputs that include the
timing and route of exposure need to be linked to PBPK models in order to develop accurate
assessment of target tissue dose. Research, especially model development, needs to extend
beyond single chemical aggregate exposures and dose to include exposures and risks that
accumulate across chemicals and over time.
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Table of Contents
Abstract iii
Executive Summary v
Tables xvi
Figures xx
Acknowledgments xxiii
Abbreviations and Acronyms xxiv
1.0 INTRODUCTION 1
1.1 Background 1
1.2 Purpose of the Report and Intended Audience 2
1.3 Structure of the Report 4
1.4 Data Treatment 5
1.5 Description of the Studies and Data Collected 5
1.6 Pesticides of Interest to this Report 7
1.7 Summary Descriptions of the Studies 9
1.8 Exposure and Dose Models 12
2.0 PESTICIDE USE PATTERNS 13
2.1 Sources of Information 13
2.2 Application Frequency 17
2.3 Application Locations 19
2.4 Application Types and Methods 20
2.5 Pesticides Identified in Inventories, Records and Wipe Samples 20
2.6 Demographic Factors Influencing Applications 21
3.0 AIR CONCENTRATION MEASUREMENTS 25
3.1 Introduction and Data Availability 25
3.2 Pesticide Presence 25
3.3 Comparisons of Air Concentrations 30
3.4 Differences Related to Location 37
3.5 Spatial and Temporal Variability 41
3.6 Factors that Influence Air Concentrations 41
3.7 Summary: Air Concentrations 43
4.0 SURFACE MEASUREMENTS 47
4.1 Introduction and Data Availability 47
4.2 Dust and Soil Measurements 50
4.3 Total Available Residue Measurements 59
4.4 Transferable Residue Measurements 66
4.5 Spatial and Temporal Variability 73
4.6 Differences Related to Location 77
4.7 Influential Factors 78
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4.8 Correlations among Soil, Wipes, and Dust 79
4.9 Particle-Bound Pyrethroid Residues: Implications toward Exposure 80
5.0 DIETARY EXPOSURE MEASUREMENTS 81
5.1 Introduction and Data Availability 81
5.2 Pesticide Presence 83
5.3 Relative Importance of the Inge sti on Route 90
6.0 INDIRECT INGESTION MEASUREMENTS 93
6.1 Characterizing Hand- and Object-to-Mouth Activities 93
6.2 Residue Loadings on Mouthed Objects and Removal by Mouthing 94
6.3 Transfer of Pesticide Residues to Food 98
6.4 Indirect Ingestion of Dust and Soil 103
6.5 Indirect Ingesti on: Summary 104
7.0 DERMAL EXPOSURE MEASUREMENTS 105
7.1 Laboratory Fluorescent Measurement Studies 106
7.2 Measurements of Pesticides on Hands by Wipe and Rinse Methods 112
7.3 Measurements with Cotton Garments 123
8.0 URINARY BIOMARKER MEASUREMENTS 129
8.1 Toxicokinetics of Organophosphate and Pyrethroid Pesticides 129
8.2 Measurements of Pesticide Metabolites in Urine 133
8.3 Temporal Variability in Biomarker Measurements 141
8.4 Urine and Creatinine Excretion among Children 144
8.5 Relative Importance of Exposure Routes 146
8.6 Model Predictions 152
9.0 SUMMARY AND CONCLUSIONS 153
10.0 REFERENCES 155
11.0 BIBLIOGRAPHY 162
APPENDIX A: Summary Statistics 165
Air Concentrations 166
Dust and Soil Concentrations and Loadings 170
Total Available Surface Residue Loadings 176
Transferable Surface Residue Loadings 179
Solid Food Concentrations and Intakes 182
Hand Loadings 186
Urinary Metabolite Concentrations 188
APPENDIX B: Individual Study Details 189
National Human Exposure Assessment Survey in Arizona (NHEXAS-AZ) 190
Minnesota Children's Pesticide Exposure Study (MNCPES) 191
Children's Total Exposure to Persistent Pesticides and Other Persistent Organic Pollutants
Study (CTEPP) 192
First National Environmental Health Survey of Child Care Centers (CCC) 193
Biological and Environmental Monitoring for Organophosphate and Pyrethroid Pesticide
Exposures in Children Living in Jacksonville, Florida (JAX) 194
Center for the Health Assessment of Mothers and Children of Salinas Quantitative Exposure
Assessment Study (CHAMACOS) 195
Children's Pesticide Post-Application Exposure Study (CPPAES) 196
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The Distribution of Chlorpyrifos Following a Crack and Crevice Type Application in the US
EPA Indoor Air Quality Research Test House (Test House) 197
A Pilot Study Examining Translocation Pathways Following a Granular Application of
Diazinon to Residential Lawns (PET) 198
Dietary Intake of Young Children (DIYC) 199
Characterizing Pesticide Residue Transfer Efficiencies (Transfer) 200
Feasibility of Macroactivity Approach to Assess Dermal Exposure (Daycare) 201
Food Transfer Studies, also known as Press Evaluation Studies (Food) 202
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Tables
Table 1.1 Available media, participant characteristics, and activities by study 8
Table 1.2 Pesticides and metabolites measured in the studies 8
Table 2.1 Pesticides use information collection methods 16
Table 2.2 Proportion (unweighted) of participants reporting pesticide use by study 18
Table 2.3 The proportion of CTEPP participants reporting use of four types of pesticides 18
Table 2.4 Pesticides inventoried in 36 households in Jacksonville, FL (JAX) in fall 2001 22
Table 2.5 Most commonly applied pyrethroids in 1217 households with complete 12 month
REJV survey data, as reported by Ozkaynak (2005) 22
Table 2.6 Number of pesticide products applied during one year (2001) in 168 child care centers
(CCC), as reported by the center directors and/or professional applicators 23
Table 2.7 Pesticides inventoried and used in 308 households in Minnesota (MNCPES) in
summer 1997 (adapted from Adgate et al, 2000) 23
Table 2.8 Detection frequencies of target analytes in soil and wipe samples in the CCC study
(weighted) and in screening wipe samples collected in JAX (unweighted) 24
Table 3.1 Summary of air sample collection methods 27
Table 3.2 Limits of detection (ng/m3) for air samples by compound and study 28
Table 3.3 Median and 95th percentile air concentrations (ng/m3, unweighted) for frequently
detected pesticides 31
Table 3.4 Spearman correlations among personal, indoor, and outdoor concentrations of
chlorpyrifos and diazinon measured in MNCPES 39
Table 3.5 Urban and rural differences in airborne concentrations of chlorpyrifos and diazinon
measured in MNCPES 39
Table 3.6 Differences in airborne concentrations measured in CTEPP for urban versus rural, low
versus medium income, and home versus daycare expressed as ratios of geometric means 39
Table 3.7 Airborne chlorpyrifos residues collected following a crack and crevice type application
versus a total release aerosol in the EPA Test House 44
Table 4.1 Studies and sample collection methods for surface measurements 48
Table 4.2 Limits of detection (ng/g or ng/cm2) for surface measurements by study, method, and
compound 49
Table 4.3 Median and 95th percentile values for soil (ng/g) and dust (ng/cm2 and ng/g)
measurements by study 52
Table 4.4 Median and 95th percentile values for total available residues (ng/cm2) by study 63
Table 4.5 Median and 95th percentile values for transferable residues (ng/cm2) by study 70
Table 5.1 Dietary exposure sample collection methods for pesticides 82
Table 5.2 Limits of detection (|ig/kg) for pesticides measured in duplicate diets 84
Table 5.3 Median and 95th percentile pesticide concentrations (|ig/kg) measured in duplicate diet
food samples 84
Table 6.1 Collection methods for the transfer of pesticide surface residues to food or objects... 95
xvi
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Table 6.2 Videotaped children's hand- and object-to-mouth activity details 96
Table 6.3 Videotaped hand-to-mouth and object-to-mouth counts 96
Table 6.4 Objects commonly mouthed by preschoolers in CTEPP 96
Table 6.5 Median and 95th percentile pesticide loadings (ng/cm2) measured on toy surfaces 97
Table 6.6 The transfer efficiency (percent transfer, mean ฑ sd) of pesticide residues from treated
surfaces to foods (relative to transfer to IP A wipes), after a 10-min contact duration (Food
Transfer Studies) 99
Table 6.7 The transfer efficiency (percent transfer, mean ฑ sd) of pesticide residues from a
treated ceramic tile surface to various foods and to an IPA Wipe (Food Transfer Studies) 100
Table 6.8 The measured and predicted ingestion (ng/day) of diazinon from the DIYC 101
Table 6.9 The estimated exposures (ng/day) of NC and OH preschool children in the CTEPP
study to chlorpyrifos, diazinon, and permethrin through indirect ingestion 103
Table 7.1 Factors commonly believed to affect dermal transfer 107
Table 7.2 Study parameters tested in surface-to-skin transfer experiments in the Characterizing
Pesticide Residue Transfer Efficiencies study 107
Table 7.3 Skin loadings (mean, standard deviation) measured following surface-to-skin transfer
experiments (initial experiments) 108
Table 7.4 Statistical analysis results (p-values) from initial surface-to-hand transfer experiments
(Riboflavin) 109
Table 7.5 Statistical analysis results (p-values) from refined, follow-up surface-to-hand transfer
experiments (Riboflavin andUvitex) 109
Table 7.6 Evidence of importance of factors tested across surface-to-skin transfer experiments.
110
Table 7.7 Limits of detection (ng/cm2) for dermal measurements by compound and study 114
Table 7.8 Median and 95th percentile values of pesticide hand loadings (ng/cm2) measured by
hand rinse (FIR) or hand wipe (HW) in the large observational field studies 114
Table 7.9 Comparison of chlorpyrifos and diazinon loadings (ng/cm2) on children's hands
measured with hand rinse (HR) and hand wipe (HW) methods 115
Table 7.10 Pesticide loading (ng/cm2) on cotton garments worn by children in three studies... 125
Table 7.11 Results of multiple linear regression modeling of measured bodysuit pesticide loading
(ng/cm2/sec) from data collected in the daycare study 126
Table 7.12 Estimates of between- and within-person variability for loading on individual
bodysuit sections 126
Table 8.1 Absorption and elimination characteristics for pesticides and urinary biomarkers of
pesticide exposure 132
Table 8.2 Summary of the children's urinary biomarker collection methods 135
Table 8.3 Urinary metabolites of organophosphate and pyrethroid pesticides measured in the
children's observational measurement studies 136
Table 8.4 Limits of detection (ng/mL) for each pesticide metabolite measured in the children's
urine samples by study 136
Table 8.5 Median and 95th percentile values (ng/mL) for the pesticide metabolites TCPy, IMP,
and 3-PBA measured in the children's urine samples by study 136
Table 8.6 Intraclass correlation coefficients (ICC) for logged CTEPP urinary metabolites 142
Table 8.7 Between- and within-person geometric standard deviations (GSDs) for logged urinary
concentrations from children in the CTEPP study 142
xvn
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Table 8.8 Estimated relative importance of the inhalation, dietary ingestion, and indirect
ingestion routes of exposure among children in CTEPP NC and OH 147
Table A.I Summary statistics for airborne chlorpyrifos concentrations (ng/m3) by study 166
Table A.2 Summary statistics for airborne diazinon concentrations (ng/m3) by study 167
Table A.3 Summary statistics for airborne malathion concentrations (ng/m3) by study 167
Table A.4 Summary statistics for airborne c/'s-permethrin concentrations (ng/m3) by study 168
Table A.5 Summary statistics for airborne trans-permethrin concentrations (ng/m3) by study. 168
Table A.6 Summary statistics for airborne TCPy concentrations (ng/m3) by study 169
Table A.7 Summary statistics for airborne IMP concentrations (ng/m3) by study 169
Table A.8 Summary statistics for chlorpyrifos concentrations measured in soil (ng/g) 170
Table A.9 Summary statistics for chlorpyrifos measured in dust, presented as both loading
(ng/cm2) and concentration (ng/g) 170
Table A. 10 Summary statistics for diazinon concentrations measured in soil (ng/g) 171
Table A.I 1 Summary statistics for diazinon measured in dust, presented as both loading (ng/cm2)
and concentration (ng/g) 171
Table A.12 Summary statistics for c/'s-permethrin concentrations measured in soil (ng/g) 172
Table A. 13 Summary statistics for c/'s-permethrin measured in dust, presented as both loading
(ng/cm2) and concentration (ng/g) 172
Table A. 14 Summary statistics for trans-permethrin concentrations measured in soil (ng/g)... 173
Table A. 15 Summary statistics for rram'-permethrin measured in dust, presented as both loading
(ng/cm2) and concentration (ng/g) 173
Table A. 16 Summary statistics for cyfluthrin concentrations measured in soil (ng/g) 174
Table A. 17 Summary statistics for cyfluthrin measured in dust, presented as both loading
(ng/cm2) and concentration (ng/g) 174
Table A. 18 Summary statistics for TCPy concentrations measured in soil (ng/g) 175
Table A. 19 Summary statistics for IMP concentrations measured in soil (ng/g) 175
Table A.20 Summary statistics for chlorpyrifos in Total Available Residue (ng/cm2) 176
Table A.21 Summary statistics for diazinon in Total Available Residue (ng/cm2) 177
Table A.22 Summary statistics for cis-permethrin in Total Available Residue (ng/cm2) 177
Table A.23 Summary statistics for trans-permethrin in Total Available Residue (ng/cm2) 178
Table A.24 Summary statistics for cyfluthrin in Total Available Residue (ng/cm2) 178
Table A.25 Summary statistics for chlorpyrifos in Transferable Residue (ng/cm2) 179
Table A.26 Summary statistics for diazinon in Transferable Residue (ng/cm2) 180
Table A.27 Summary statistics for c/'s-permethrin in Transferable Residue (ng/cm2) 180
Table A.28 Summary statistics for trans-permethrin in Transferable Residue (ng/cm2) 181
Table A.29 Summary statistics for cyfluthrin using in Transferable Residue (ng/cm2) 181
Table A.30 Summary statistics for chlorpyrifos measured in solid food, presented as both intake
(ug/day) and concentration (ug/kg) 182
Table A.31 Summary statistics for diazinon measured in solid food, presented as both intake
(ug/day) and concentration (ug/kg) 183
Table A.32 Summary statistics for c/'s-permethrin measured in solid food, presented as both
intake (ug/day) and concentration (ug/kg) 184
Table A.33 Summary statistics for trans-permethrin measured in solid food, presented as both
intake (ug/day) and concentration (ug/kg) 184
Table A.34 Summary statistics for TCPy measured in solid food, presented as both intake
(ug/day) and concentration (ug/kg) 185
xvin
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Table A.35 Summary statistics for IMP measured in solid food, presented as both intake (ug/day)
and concentration (ug/kg) 185
Table A.36 Summary statistics for chlorpyrifos hand loadings (ng/cm2) 186
Table A.37 Summary statistics for diazinon hand loadings (ng/cm2) 186
Table A.38 Summary statistics for c/'s-permethrin hand loadings (ng/cm2) 186
Table A.39 Summary statistics for trans-permethrin hand loadings (ng/cm2) 187
Table A.40 Summary statistics for TCPy hand loadings (ng/cm2) 187
Table A.41 Summary statistics for IMP hand loadings (ng/cm2) 187
Table A.42 Summary statistics for TCPy measured in urine (ng/mL) 188
Table A.43 Summary statistics for 3-PBA measured in urine (ng/mL) 188
Table A.44 Summary statistics for IMP measured in urine (ng/mL) 188
xix
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Figures
Figure 1.1 Modeling framework for children's pesticide exposure from Cohen Hubal etal.
(2000b) 3
Figure 2.1 Weighted percentage of child care centers reporting treatment of various rooms in the
Child Care Centers (CCC) study 19
Figure 3.1 Frequency of detection of pesticides measured in indoor and outdoor air in selected
studies 29
Figure 3.2 Log probability plots for chlorpyrifos, diazinon, and c/'s-permethrin measured in large
observational field studies 32
Figure 3.3 Log probability plots for /ram'-permethrin, TCPy, and IMP measured in large
observational field studies 33
Figure 3.4 Indoor and outdoor air concentrations of chlorpyrifos, diazinon, and c/'s-permethrin
measured in selected studies 34
Figure 3.5 Indoor and outdoor air concentrations of frYms-permethrin and TCPy measured in
selected studies 35
Figure 3.6 Log-scale relationships between levels of parent pesticide (ng/m3) and degradate
(ng/m3) measured in CTEPP 36
Figure 3.7 The detection frequencies of select pesticides and their metabolites measured from the
indoor air (A) and outdoor air (B) of homes and daycares inNC and OH 40
Figure 3.8 Airborne concentrations (ng/m3) of chlorpyrifos or diazinon measured from indoor air
over time in the Test House, PET, CPPAES, and DIYC studies 45
Figure 3.9 Association between measured air concentration (ng/m3) and Applied Effective
Volume (ng/m3/h) on the second day after application of chlorpyrifos in CPPAES homes 46
Figure 3.10 Pesticide air concentrations as a function of vapor pressure in CTEPP homes (A) and
daycares (B) 46
Figure 4.1 Detection frequencies of pesticides and degradates in soil 53
Figure 4.2 Detection frequencies of pesticides and degradates in dust 53
Figure 4.3 Lognormal probability plots of soil concentrations (ng/g) for chlorpyrifos, diazinon,
c/s-permethrin, frYms-permethrin, cyfluthrin, and TCPy 54
Figure 4.4 Lognormal probability plots of dust concentrations (ng/g) and loadings (ng/cm2) for
chlorpyrifos, diazinon, and c/'s-permethrin 55
Figure 4.5 Lognormal probability plots of dust concentrations (ng/g) and loadings (ng/cm2) for
^raซ5-permethrin, cyfluthrin, and TCPy 56
Figure 4.6 Box-and-whisker plots of dust concentrations (ng/g) and loadings (ng/cm2) for
chlorpyrifos, diazinon, and c/s-permethrin 57
Figure 4.7 Box-and-whisker plots of dust concentrations (ng/g) and loadings (ng/cm2) for trans-
permethrin, cyfluthrin, and TCPy 58
Figure 4.8 Detection frequencies for pesticides using total available residue collection methods.
62
xx
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Figure 4.9 Lognormal probability plots for the most frequently detected pesticides which include
chlorpyrifos, diazinon, cis- and ^ram'-permethrin, cyfluthrin, and cypermethrin 64
Figure 4.10 Box-and-whisker plots of total available residue surface loadings (ng/cm2) for
chlorpyrifos, diazinon, c/s-permethrin, ^ram'-permethrin, cypermethrin, and esfenvalerate 65
Figure 4.11 Detection frequencies for pesticides using transferable residue collection methods. 68
Figure 4.12 Lognormal probability plots for transferable residue loadings for the most frequently
detected pesticides which include chlorpyrifos, diazinon, and cis- and ^ram'-permethrin from
CTEPP 71
Figure 4.13 Box-and-whisker plots for transferable residue loadings for the most frequently
detected pesticides which include chlorpyrifos, diazinon, cis- and ^rara'-permethrin, cyfluthrin,
andTCPy 72
Figure 4.14 Total available surface residue loadings measured in multiple rooms over time in the
Test House, in multiple rooms in ten homes in CPPAES, and on multiple surfaces in three homes
inDIYC 75
Figure 4.15 Transferable residue measurements overtime following an application from multiple
locations in multiple rooms of the Test House and multiple surfaces in three homes in DIYC... 75
Figure 4.16 Total available residue measurements from the Daycare study 76
Figure 4.17 Spatial variability in deposition coupon loadings in the kitchen (application site) and
den (adjoining room) of Test House following pesticide application 76
Figure 5.1 The detection frequency of pesticides measured in duplicate diet food samples 85
Figure 5.2 Lognormal probability plots of solid food concentrations (ng/kg) and intakes (jig/day)
for chlorpyrifos, diazinon, and c/'s-permethrin from large observational field studies 86
Figure 5.3 Lognormal probability plots of solid food concentrations (|ig/kg) and intakes (jig/day)
for frYms-permethrin, TCPy, and IMP from large observational field studies 87
Figure 5.4 Box-and-whisker plots of solid food concentrations (|ig/kg) and intakes (jig/day) for
chlorpyrifos, diazinon, and c/'s-permethrin across all studies 88
Figure 5.5 Box-and-whisker plots of solid food concentrations (|ig/kg) and intakes (jig/day) for
rram'-permethrin, TCPy, and IMP across all studies 89
Figure 5.6 Comparison of SHEDS model prediction for dietary intake of c/'s-permethrin
(|ig/kg/day) and CTEPP measurement data 90
Figure 5.7 Estimated mean proportion of aggregate potential exposure for CTEPP-NC children
by exposure route 91
Figure 5.8 Estimated mean proportion of aggregated potential exposure for CTEPP-OH children
by exposure route 92
Figure 6.1 Comparison of the median hand-to-mouth and object-to-mouth contacts per hour
among CPPAES and MNCPES children 97
Figure 6.2 Comparison of measured and predicted ingestion of diazinon (ng/day) from the
DIYC 102
Figure 7.1 Comparison of transfer efficiencies of fluorescent tracers and pesticides from laminate
and carpet surfaces to various sampling media 110
Figure 7.2 Hand loading by contact number, from the refined, follow-up experiments using
Riboflavin (left panels) or Uvitex (right panels) Ill
Figure 7.3 Log probability plots of hand loadings (MNCPES data are hand rinses, all others are
hand wipes) 116
Figure 7.4 Comparison of hand loadings across studies 117
xxi
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Figure 7.5 Ratios of hand wipe loading to floor wipe loading (left panel) and hand wipe loading
to dust loading (right panel) for pesticides in CTEPP 118
Figure 7.6 Relationship between children's hand loadings measured at CTEPP homes and
daycares 119
Figure 7.7 Relationship between hand loadings among children and adults in CTEPP 120
Figure 7.8 Relationship between hand wipe measurements and floor wipe measurements in
CTEPP 121
Figure 7.9 Relationship between hand wipe measurements and floor dust measurements in
CTEPP 122
Figure 7.10 Bodysuit section loadings (ng/cm2) by monitoring period from the Daycare study 127
Figure 7.11 Relative standard deviations of esfenvalerate loadings on cotton garment sections
among infants and preschoolers in the Daycare study 128
Figure 7.12 Handwipe loadings (ng/cm2) above method detection limit among infants and
preschoolers in the Day care study 128
Figure 8.1 Detection frequencies of pesticide metabolites in the children's urines samples by
study 137
Figure 8.2 Log probability plots of urinary TCPy, 3-PBA, and IMP concentrations across large
observational field studies. NHANES results are included for comparison 138
Figure 8.3 Box-and-whisker plots comparing the urinary TCPy and 3-PBA concentrations across
studies 139
Figure 8.4 Urinary TCPy concentrations (ng/mL) over time for the children in the high and low
application groups in CPPAES 140
Figure 8.5 Time profiles for chlorpyrifos in environmental media and TCPy concentrations in
urine for all children in the CPPAES 140
Figure 8.6 Concentration versus time plots for urinary TCPy measurements among CTEPP-NC
and CTEPP-OH participants reporting a recent pesticide application 143
Figure 8.7 Time-concentration profile for urinary IMP measurements among child and adult PET
study participants following an outdoor granular turf pesticide application 143
Figure 8.8 Estimates of age-specific urinary output and creatinine excretion, based on data from
theMNCPES 145
Figure 8.9 The median estimated intakes of chlorpyrifos and TCPy in CTEPP-NC compared with
the excreted median amounts of TCPy in the preschool children's urine 147
Figure 8.10 Intake of environmental TCPy through the dietary route correlated poorly (r2=0.01)
with the amount of TCPy excreted in the urine of CTEPP-NC preschool children 148
Figure 8.11 Estimated distributions of aggregate intake ("AGGR") of chlorpyrifos and
permethrin (ng/kg/day) and estimated distributions of the four contributing routes 148
Figure 8.12 The contributions of inhalation, dermal absorption, diet, and nondietary ingestion to
aggregate intake of c/s-permethrin 149
Figure 8.13 Children's estimated aggregate intake of chlorpyrifos and permethrin compared to
their measured urinary metabolites (CTEPP) 149
Figure 8.14 Distributions of TCPy in urine across studies (bottom right panel) in comparison to
distributions of chlorpyrifos in indoor air, outdoor air, dust, and soil across studies 150
Figure 8.15 Distributions of TCPy in urine across studies (bottom right panel) in comparison to
distributions of chlorpyrifos on surfaces, in solid food, and on hands across studies 151
Figure 8.16 Comparison of TCPy in urine between SHEDS model and observed MNCPES data
when TCPy in the environment is not considered (Source: Xue et al, 2004) 152
xxn
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Acknowledgments
We would like to acknowledge the many researchers and support staff who contributed to this
report by their design and implementation of the included studies. The contributors are too
numerous to acknowledge individually, but the organizations that collaborated on this research
are listed in the report and Appendix B. This report would not be possible without all of the hard
work that was put into the individual studies. A number of other researchers in the Human
Exposure and Atmospheric Sciences Division, including Dr. Jianping (Jim) Xue, Mr. Thomas
McCurdy, Dr. Rogelio Tornero-Velez, and Mr. M. Scott Clifton, made valuable contributions to
this report by their analyses of data, reviews, and comments.
We would like to acknowledge the EPA Program Office scientists, NERL researchers, and
Science to Achieve Results (STAR) program grantees who gathered at the NERL Workshop on
the Analysis of Children's Measurements Data (Tulve etal., 2006) in September 2005 to assess
the suitability of the data for testing key hypotheses and to suggest additional analyses.
The authors also gratefully acknowledge the time, effort, and constructive comments offered by
the peer reviewers, Dr. Laura Geer (Johns Hopkins University), Dr. Miles Okino (EPA), Dr. B.J.
George (EPA), and Dr. Valerie Zartarian (EPA). The comprehensive review and comments by
Mr. Kent Thomas (Associate Director for Human Health in the Human Exposure and
Atmospheric Sciences Division) also contributed significantly to the quality of the final
document.
We would especially like to thank all of the study participants who worked so generously with
the researchers to help make these observational studies a success.
xxin
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Abbreviations and Acronyms
%Det
2,4-D
3-PBA
ACH
AER
AEV
ANOVA
ASTM
ATSDR
AZ
CIS Press
ccc
CDC
CDIM
CHA
CHAMACOS
cis-P
c-Perm
c-Permethrin
CPPAES Pre
CPPAES
CRE
CTEPP
CTEPP-NC
CTEPP-NC d
CTEPP-NC DAYCARE
CTEPP-NC h
CTEPP-NC HOME
CTEPP-OH
CTEPP-OH d
CTEPP-OH DAYCARE
CTEPP-OH h
CTEPP-OH HOME
DAP
Percent of samples above detection limit
2,4-Dichlorophenoxyacetic acid
3-Phenoxybenzoic acid
Air exchanges per hour
Air exchange rate
Application effective volume
Analysis of variance
American Society for Testing and Materials
Agency for Toxic Substances and Disease Registry
National Human Exposure Assessment Survey in Arizona
CIS surface press sampler
First National Environmental Health Survey of Child Care
Centers Study
Centers for Disease Control
Children's Dietary Intake Model
Center for the Health Assessment of Mothers and Children
of Salinas Quantitative Exposure Assessment Study
Center for the Health Assessment of Mothers and Children
of Salinas Quantitative Exposure Assessment Study
c/5-Permethrin
c/5-Permethrin
c/5-Permethrin
CPPAES Study, pre-application days only
Children's Pesticide Post-Application Exposure Study
Creatinine
Children's Total Exposure to Persistent Pesticides and
Other Persistent Organic Pollutants Study
CTEPP Study, North Carolina homes and daycares
CTEPP Study, North Carolina daycares only
CTEPP Study, North Carolina daycares only
CTEPP Study, North Carolina homes only
CTEPP Study, North Carolina homes only
CTEPP Study, Ohio homes and daycares
CTEPP Study, Ohio daycares only
CTEPP Study, Ohio daycares only
CTEPP Study, Ohio homes only
CTEPP Study, Ohio homes only
Dialkylphosphate
xxiv
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Daycare / DAYCARE
Dep Coup
DC
DCHD
DEBT
DIYC
EOSHI
Food
FQPA
GC/ECD
GC/MS
GLM
GM
GSD
HUD
HVS3
ICC
IMP / IMPy
IPA
IPA Wipe
JAX
JAX-AG
JAX-AGG
JAXAGGREGATE
JAX-SC
JAX-SCR
JAXSCREENING
LOD
LWW
Max
MCPA
MDA
MDL
MGK 264
Min
MNCPES / MN
MPA
N
NC Daycare
NCDC
NCHM
NC Home
Feasibility of Macroactivity Approach to Assess Dermal
Exposure Study
Deposition coupon
Deposition coupon
Duval County Health Department
N,N-diethyl-meta-toluamide
Dietary Intake of Young Children Study
Environmental and Occupational Health Sciences Institute
Study
Food Transfer Studies
Food Quality Protection Act
Gas Chromatography/Electron Capture Detector
Gas Chromatography/Mass Spectroscopy
Generalized linear model
Geometric mean
Standard deviation of the geometric mean
US Department of Housing and Urban Development
High Volume Small Surface Sampler
Intraclass Correlation Coefficient
2-Isopropyl-6-methyl-4-pyrimidinol
Isopropyl alcohol
Isopropyl alcohol wipe
Biological and Environmental Monitoring for
Organophosphate and Pyrethroid Pesticide Exposures in
Children Living in Jacksonville, Florida Study
JAX Study, Aggregate Exposure Assessment phase
JAX Study, Aggregate Exposure Assessment phase
JAX Study, Aggregate Exposure Assessment phase
JAX Study, Screening phase
JAX Study, Screening phase
JAX Study, Screening phase
Limit of detection
Lioy-Weisel-Wainman wipe sampler
Maximum
(4-chloro-2-methylphenoxy)acetic acid
Malathion dicarboxylic acid
Minimum detection limit
N-octyl bicycloheptene dicarboximide
Minimum
Minnesota Children's Pesticide Exposure Study
2-methyl-3-phenylbenzoic acid
Sample size
CTEPP Study, North Carolina daycares only
CTEPP Study, North Carolina daycares only
CTEPP Study, North Carolina homes only
CTEPP Study, North Carolina homes only
XXV
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NC
NERL
NHANES
NHEXAS-AZ
NOPES
NRMRL
OCHP
OH Daycare
OH DC
OHHM
OH Home
OH
OP
OPP
OPPT
ORD
P25
P50
P75
P95
PBPK
PET
PUF
PYR
REJV
RTI
SD
SHEDS
STAR
TCPY / TCP / TCPy
TE
TEST / TESTHOUSE / Test House
TESTHOUSE Pre
^-Permethrin
r-Perm
trans-?
Transfer
US CPSC
US EPA
VTD
North Carolina
National Exposure Research Laboratory
National Health and Nutrition Examination Survey Study
National Human Exposure Assessment Survey in Arizona
Non-Occupational Pesticide Exposure Study
National Risk Management Research Laboratory
Office of Children's Health Protection
CTEPP Study, Ohio daycares only
CTEPP Study, Ohio daycares only
CTEPP Study, Ohio homes only
CTEPP Study, Ohio homes only
CTEPP Study, Ohio
Organophosphate
Office of Pesticide Programs
Office of Pollution Prevention and Toxics
Office of Research and Development
25th percentile
Median / 50th percentile
75th percentile
95th percentile
Physiologically-Based Pharmacokinetic Model
A Pilot Study Examining Translocation Pathways
Following a Granular Application of Diazinon to
Residential Lawns Study
Polyurethane foam
Pyrethroid
Residential Exposure Joint Venture
Research Triangle Institute
Standard deviation of the arithmetic mean
Stochastic Human Exposure and Dose Simulation Model
Science to Achieve Results
3,5,6-Trichloro-2-pyridinol
Transfer Efficiency
The Distribution of Chlorpyrifos Following a Crack and
Crevice Type Application in the US EPA Indoor Air
Quality (IAQ) Research House Study
Test House Study, pre-application day only
tmns-Permethrin
trans-Permethrin
trans-Permethrin
Characterizing Pesticide Residue Transfer Efficiencies
US Consumer Product Safety Commission
U.S. Environmental Protection Agency
Virtual Timing Device
xxvi
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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. Children are behaviorally and physiologically different from adults.
Their interaction with their environment, through activities such as playing on floors, and
mouthing of hands and objects, and handling of food, may increase contact with contaminated
surfaces. Proportionately higher breathing rates, relative surface area, and food intake
requirements may increase exposure. Differences in absorption, metabolism, storage, and
excretion may result in higher biologically effective doses to target tissues. Immature organ
systems may be more susceptible to toxicological challenges. Windows of vulnerability, when
specific toxicants may permanently alter the function of an organ system, are thought to exist at
various stages of development.
Children are exposed to a wide variety of chemicals in their homes, schools, daycare centers, and
other environments that they occupy. The chemicals to which they are exposed may originate
from outdoor sources, such as ambient air contaminants, indoor sources such as building
materials and furnishings, and from consumer products used indoors. One category of consumer
products to which children may be exposed is pesticides that are used to control roaches, rats,
termites, ants, and other vermin. Despite widespread residential and agricultural use of
pesticides, only limited measurement data are available for pesticide levels in environments that
children occupy and little is known about the factors that impact children's exposures to
pesticides. The Food Quality Protection Act (FQPA) of 1996 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. FQPA requires risk assessments to be based on
exposure data that are of high quality and high quantity or on exposure models using factors that
are based on existing, reliable data.
EPA's Office of Research and Development (ORD) is responsible for conducting research to
provide the scientific foundation for risk assessment and risk management at EPA. In 2000,
ORD released its Strategy for Research on Environmental Risks to Children addressing research
needs and priorities associated with children's exposure to environmental pollutants and
providing a framework for a core program of research in hazard identification, dose-response
evaluation, exposure assessment, and risk management.
The National Exposure Research Laboratory (NERL) in ORD is working to achieve three
specific objectives of the Strategy through its children's exposure research program: (1) develop
improved exposure assessment methods and models for children using existing information;
(2) design and conduct research on age-related differences in exposure, effects, and dose-
response relationships to facilitate more accurate risk assessments for children; and (3) explore
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opportunities for reducing risks to children. After an exhaustive review of the volume and
quality of the data upon which default assumptions for exposure factors are based (Cohen Hubal
et al, 2000a), a framework for systematically identifying the important sources, routes, and
pathways for children's exposure was developed (Cohen Hubal etal., 2000b).
This framework (Figure 1.1), based on a conceptual model for aggregate exposure, provides the
foundation for a protocol for measuring aggregate exposures to pesticides (Berry et al., 2001)
and for developing sophisticated stochastic models (Zartarian et al., 2000). Using the
framework, four priority research areas, representing critical data gaps in our understanding of
environmental risks to children, have been identified:
(1) Pesticide use patterns;
(2) Spatial and temporal distribution in residential dwellings;
(3) Dermal absorption and indirect (non-dietary) ingestion (including micro- and
macro-activity approaches); and
(4) Direct ingestion.
Several targeted studies were designed and conducted to address these research needs. These
include laboratory studies, small pilot field studies, and large collaborative observational studies.
These studies aimed to: (1) evaluate methods and protocols for measuring children's exposure,
(2) collect data on exposure factors to reduce the uncertainty in exposure estimates and risk
assessments, and (3) collect data for use in exposure model development and evaluation.
1.2 Purpose of the Report and Intended Audience
This document is a comprehensive summary report of data collected under or otherwise related
to the NERL children's exposure research program. Data are compared across studies and across
compounds to identify or evaluate important factors influencing exposures along each relevant
pathway. Summary statistics, comparative analyses, and spatial and temporal patterns are
presented to address previously identified data gaps. The primary purpose of this document is to
identify factors that are most important for children's exposures to pesticides. The objectives of
this document are to:
Compare results across studies in order to identify trends or similar observations that
might provide a better understanding of the factors affecting children's exposures;
Describe recent children's exposure studies conducted or funded by NERL, including
descriptions of the parameters measured and the measurement methods;
Provide concentration data and summary statistics for comparison of the studies; and
Present highlights of the results of the studies.
The document was completed with input from staff in the EPA Program Offices, NERL
researchers, and Science to Achieve Results (STAR) program grantees who gathered at the US
EPA National Exposure Research Laboratory's Workshop on the Analysis of Children's
Measurement Data (Tulve et al., 2006) in September 2005 to discuss data presented in a draft
summary report, assess the suitability of the data for testing key hypotheses, and propose
additional analyses.
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Source
indoor
residential
ป outdoor
residential
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agricultural
Release
&
Transfer
Exposure \
Media
Outdoor
ป air
ป water
ป soil
ป plants
ป surfaces
A
f
T
Indoor
ซ air
ซ water
house dust
food
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ซ clothes
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Activ
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Inhalation
Inhalation
R,
Respiratory
Tract
Inhalation
Exposure
Rate
R.T. Uptake
Dermal
Contact
Ingestion
\ Rate /
Dietary Ingestion
-Exposure
Figure 1.1 Modeling framework for children's pesticide exposure from Cohen Hubal et al.
(2000b).
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The document is intended for an audience of exposure scientists, exposure modelers, and risk
assessors. Exposure scientists will find a useful evaluation of available sampling methods for all
media relevant to children's exposures. Exposure modelers will be able to use the data to
develop or improve probabilistic multimedia, multi-pathway human exposure models. Most
significantly, the report may be used by EPA Program offices such as the Office of Pesticide
Programs (OPP), the Office of Pollution Prevention and Toxics (OPPT), and the Office of
Children's Health Protection (OCHP) to enhance the Agency's risk assessment activities by
replacing default assumptions with high-quality, real-world data. Fewer default assumptions will
lead to more accurate assessments of exposure and risk and will bolster ensuing risk reducing
actions. Furthermore, by examining relationships among application patterns, exposures, and
biomarkers for multiple compounds from different classes of pesticides, this report contributes to
the development of more reliable approaches for assessing cumulative exposure. Some of the
analyses and comparisons that are presented in this summary report include the following:
Comparison of concentrations
Spatial variability
Temporal variability
Regional comparisons
Urban versus rural
Home versus daycare
Indoor versus outdoor
Parent compound versus metabolite
Effect of physical and chemical properties
Impact of air exchange rate
Effect of surface type
Effect of surface concentration
Effect of sampling method
Comparisons between studies may involve different numbers of measurements, different
sampling strategies and methods, and different chemical analysis methods
1.3 Structure of the Report
This document presents data from studies to evaluate children's exposure to pesticides, spanning
from pesticide use patterns, through concentrations in exposure media, to biological markers of
exposure. The exposure media are listed in an order that roughly mirrors the complexity of the
exposure mechanism; that is, beginning with inhalation exposure and ending with dermal
exposure. At the beginning of each section, available data from the relevant studies are listed.
Results are presented in tables and graphs to illustrate the available data and to facilitate
comparisons both across studies and across pesticides.
Throughout the document, lognormal probability plots ("logplots") and box-and-whisker plots
("box plots") are used to graphically depict and compare distributions of concentrations or
surface loadings. The logplots are used to compare results only from large observational field
studies and the boxplots are used to compare results from the focused studies against each other
and against the large observational field studies. In the lognormal probability plot, the ordered
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values of the measured concentration are plotted on a log-scale vertical axis, and the percentiles
of the theoretical normal distribution are plotted on the horizontal axis. If the points in the plot
form a nearly straight line, the data are approximately lognormal. The box-and-whisker plot is
actually a group of side-by-side box-and-whisker plots along the x-axis, each representing a
different study. The upper whisker extends to the maximum value, the upper edge of the box
represents the 75th percentile, the line inside the box represents the median (50th percentile), the
lower edge of the box represents the 25th percentile, and the lower whisker extends to the
minimum value. Note that the vertical axis is log-scale.
1.4 Data Treatment
Values that are below the method detection limit (MDL) are common in environmental data sets.
All values above the MDL are statistically different from zero; however, values near the MDL
are generally less accurate than those much higher than the MDL. Laboratories often report a
second limit, the Method Quantitation Limit (MQL), as the smallest amount that can be reliably
quantified m a sample. Despite the higher relative uncertainty in values between the MDL and
the MQL, all values above the MDL are retained for the purposes of this document. Values
below the MDL are treated using simple substitution, wherein they are replaced with a fraction
of the detection limit (MDL//2), a common practice originally proposed by Hornung and Reed
(1990). These substituted values are used in all statistical analyses performed specifically for
this report and are presented in all data plots, except for lognormal probability plots, in which
these substituted values were judged by the authors to be misleading. Detection frequencies (that
is, the percent of measurements above the MDL) are presented for each compound by each
relevant sampling method at the beginning of each chapter.
Sampling weights are available for all of the large-scale observational field studies, but, unless
otherwise noted, only unweighted concentrations are presented in this report. Summary statistics
based on unweighted observations may not provide as valid an estimate of true study population
values as those based on weighted observations, but are used nonetheless to maintain consistency
in comparisons with studies for which weights are not available. In all cases where a statistical
test was done to assess differences, the name of the test and the resulting p-value are presented.
1.5 Description of the Studies and Data Collected
Data are included in this report from the following studies. (The acronyms in parentheses are
used in the Tables and Figures of this report.)
National Human Exposure Assessment Survey in Arizona (NHEXAS-AZ)
Minnesota Children's Pesticide Exposure Study ("MNCPES")
Children's Total Exposure to Persistent Pesticides and Other Persistent Organic
Pollutants ("CTEPP")
First National Environmental Health Survey of Child Care Centers ("CCC")
Biological and Environmental Monitoring for Organophosphate and Pyrethroid Pesticide
Exposures in Children Living in Jacksonville, Florida ("TAX")
Center for the Health Assessment of Mothers and Children of Salinas Quantitative
Exposure Assessment Study ("CHAMACOS")
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Children's Pesticide Post-Application Exposure Study ("CPPAES")
Distribution of Chlorpyrifos Following a Crack and Crevice Type Application in the US
EPA Indoor Air Quality Research Test House ("Test House")
Pilot Study Examining Translocation Pathways Following a Granular Application of
Diazinon to Residential Lawns ("PET")
Dietary Intake of Young Children ("DIYC")
Characterizing Pesticide Residue Transfer Efficiencies ("Transfer")
Food Transfer Studies ("Food")
Feasibility of Macroactivity Approach to Assess Dermal Exposure ("Daycare")
All studies involving children were observational research studies, as defined in 40 CFR Part
26.402. All study protocols and procedures to obtain the assent of the children and informed
consent of their parents or guardians were reviewed and approved by independent Institutional
Review Boards (IRBs) and complied with all applicable requirements of the Common Rule (45
CFR 46) regarding additional protections for children (Subpart D). Further, all protocols
regarding recruitment and treatment of participants were reviewed by the EPA Human Subjects
Research Review Official (HSRRO) to assure compliance with the Federal Policy for the
Protection of Human Subjects.
The studies discussed in the report included large observational studies, such as NHEXAS-AZ,
MNCPES, CTEPP, and CCC, small pilot-scale observational studies (e.g., JAX, CPPAES,
DIYC, CHAMACOS, and Daycare), and laboratory studies (e.g., Test House, Transfer, and
Food).
MNCPES, NHEXAS-AZ, CTEPP, and CCC were large observational exposure
measurement studies with survey designs that involved random sampling. The CCC
study was a nationwide survey and the others had a regional focus. Sampling weights are
available for all of these studies, but, unless noted otherwise, only unweighted
concentrations are presented in this report.
The small pilot-scale observational studies are small-scale field studies, such as JAX and
CHAMACOS, which were performed to evaluate methods for conducting aggregate
exposure assessments for pesticides and to collect preliminary data that could be used to
assist in the design of larger observational studies. Like the large observational studies,
some of these smaller studies included measurements of multiple chemicals in multiple
media.
The laboratory studies consisted of experiments under controlled conditions to evaluate
factors affecting transfer from surfaces (Transfer and Food studies). The Test House
study investigated the fate and transport of chlorpyrifos following a crack and crevice
application and provided valuable information on spatial and temporal variability of
surface concentrations in the absence of human activity.
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During these studies, the following types of measurements were collected (not all types of
samples were collected in all studies):
Air (indoor and outdoor)
Soil
House dust - Floors (carpet and hard surface)
Surface wipes (including eating and food preparation surfaces)
Transferable residues (e.g.., polyurethane foam roller, CIS press)
Hand wipes
Dermal surrogates (cotton garment and socks)
Duplicate diet (solid food, beverages)
Handled food
Urine
Information was also typically collected by questionnaire on:
Housing characteristics
Participant characteristics
Children's activities (timelines and logs)
Recent pesticide use
The types of media sampled and questionnaires administered in each study are listed in Table
1.1. Other than the pesticide inventory and use questionnaires, questionnaire data are not the
focus of this document.
1.6 Pesticides of Interest to this Report
The studies presented here were performed when a number of organophosphate and pyrethroid
pesticides were in use; thus numerous pesticides from various chemical classes (including
insecticides and herbicides) were measured. All measured insecticides (and insecticides
synergists) are listed in Table 1.2, although not all of the studies collected data for all of the
insecticides listed. To reduce complexity, this report focuses on the most commonly detected
organophosphate and pyrethroid insecticides:
Chlorpyrifos
Diazinon
Permethrin
Cyfluthrin
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Table 1.1 Available media, participant characteristics, and activities by study.
Air - Indoor
Air - Outdoor
House Dust
Surface Residue Wipes
LWW Surface Sampler
Transferable Residues
Hand Wipes
Cotton Garments/Socks
Soil
Duplicate Diet
Handled Foods
Urine
Housing Characteristics
Participant Characteristics
Children's Activities
Recent Pesticide Use
Pesticide Inventory
NHEXAS-AZ
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1.7 Summary Descriptions of the Studies
Individual study details are listed in Appendix B. Journal articles presenting results of these
studies are listed in the Bibliography. The studies are summarized below.
The National Human Exposure Assessment Survey in Arizona (NHEXAS-AZ) was performed in
collaboration with the University of Arizona, the Illinois Institute of Technology, and Battelle
Memorial Institute. Probability-based samples were collected in each of Arizona's 15 counties
from December 1995 to March 1997. Although 176 households participated, this report only
includes data from 21 households with children ages 6-12 as primary participants. Environ-
mental samples included indoor and outdoor air (3-day integrated samples), personal air (1-day),
vacuumed surface dust, and window sill wipes. Personal samples included 24-hour duplicate
diet and hand wipes. Biological samples consisted of urine samples (first morning void).
Baseline and follow-up questionnaires and time-activity diaries captured activity patterns. Two
pesticides (and their metabolites) were of primary interest, namely chlorpyrifos (TCPy) and
diazinon, and two pesticides (and their metabolites) were of secondary interest, namely
malathion (MDA) and carbaryl (1-naphthol).
The Minnesota Children's Pesticide Exposure Study (MNCPES) was an observational measure-
ment study performed in collaboration with Research Triangle Institute (RTI), the Environmental
and Occupational Health Sciences Institute (EOHSI), the Minnesota Department of Health, and
the University of Minnesota. A telephone survey and in-home interviews were used to collect
data on pesticide storage and use patterns from 308 households in both urban centers (Minneap-
olis/St. Paul) and rural counties (Goodhue and Rice) during the summer of 1997. Probability-
based sampling weights were developed and intensive environmental and personal monitoring
were performed for 102 children, ages 3-13. Households reporting more frequent pesticide use
were oversampled. Environmental samples included personal, indoor, and outdoor air (6-day
integrated), surface dust (wipe and press), surface soil, and tap water. Personal samples included
solid food (4-day composite), beverages (4-day composite), hand rinse, and first morning void
urine (days 3, 5, and 7). In addition to questionnaires and diaries, videotaping was performed in
a subset of 20 homes. Four primary pesticides (and their metabolites), namely chlorpyrifos
(TCPy), atrazine (atrazine mercapturate), malathion (malathion dicarboxylic acid), and diazinon,
and 14 secondary pesticides were measured, along with 13 poly cyclic aromatic hydrocarbons
(PAHs).
The Children's Total Exposure to Persistent Pesticides and Other Persistent Organic Pollutants
(CTEPP) Study (Morgan et al, 2004) was performed in collaboration with Battelle Memorial
Institute as an observational study of preschool children's exposure to contaminants in their
everyday environments (i.e., homes and day care centers). Monitoring was performed from July
2000 to March 2001 in North Carolina (spanning summer, fall, and winter) and from April 2001
to November 2001 in Ohio (spanning spring, summer, and fall). The study population consisted
of 257 children, ages 18 months to five years, and their primary adult caregivers (130 children,
130 homes, and 13 day care centers in North Carolina; 127 children, 127 homes, and 16 day care
centers in Ohio). Samples were collected over a 48-hr period at each home and daycare center,
including indoor air, outdoor air, floor dust, soil, hand wipe, solid food, liquid food, and urine.
Supplemental information included a recruitment survey, a house/building characteristics survey,
pre- and post monitoring questionnaires, and activity and food diaries. In addition, 20% of the
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OH participants were videotaped at home for about 2 hours. Additional samples (hard floor and
food preparation surface wipes and transferable residues) were collected if the participant
reported indoor or outdoor applications of pesticides within 7 days of the monitoring period.
The First National Environmental Health Survey of Child Care Centers (CCC) was performed in
collaboration with HUD (US Department of Housing and Urban Development) and CPSC (US
Consumer Product Safety Commission). Samples were collected from August through October
(summer and fall) 2001, at 168 randomly-selected child care centers nationwide. Many facilities
reported recent pesticide application (either by professionals or by employees). Samples
included soil, surface wipes, and transferable residues (CIS Press). A multi-residue chemical
analysis method was used to measure a large suite of current-use pesticides. The study aimed to
collect data on pesticide use practices and to characterize the distributions of pesticide
concentrations in a nationally-representative sample of child care centers in the U.S.
The study titled Biological and Environmental Monitoring for Organophosphate and Pyrethroid
Pesticide Exposures in Children Living in Jacksonville, Florida (JAX) was performed in collab-
oration with CDC (Centers for Disease Control and Prevention) and DCHD (Duval County
Health Department) in Jacksonville (Duval County), Florida, from August through October
(summer and fall) 2001. The CDC performed a biomonitoring study to measure metabolites of
organophosphate and pyrethroid pesticides in a sample of 200 children who were 4-6 years of
age. The DCHD conducted a home screening survey in a subset of 42 of the homes. The
screening phase employed a pesticide screening inventory, surface wipes, and urine collection.
The EPA conducted an observational study in a subset of nine of the homes to evaluate sampling
and analysis methods and protocols for conducting aggregate exposure estimates for children.
The aggregate exposure study included the pesticide screening inventory, surface wipes, indoor
and outdoor air, cotton garment, duplicate diet, and transferable residue measurements, a time
activity diary, and a urine sample.
The Center for the Health Assessment of Mothers and Children of Salinas (CHAMACOS)
Quantitative Exposure Assessment Study was a collaboration with the University of California at
Berkeley. This observational study was performed in homes of agricultural workers living in
Salinas, California. Twenty households with children ages 5 months to 3 years old (10 female
and 10 male) were monitored during the period of June to October (summer and fall) 2002.
Samples were collected over a 24-hour monitoring period and included indoor and outdoor air,
house dust, transferable residues from floors (surface wipes and press samples), transferable
residues from toys (surface wipes), urine, and cotton union suits and socks. A time/activity diary
was also administered. The objective of the study was to evaluate sampling and analysis
methods and study protocols that might be applied in larger studies such as the National
Children's Study.
The Children's Pesticide Post-Application Exposure Study (CPPAES) was a collaborative field
study with EOHSI (Environmental and Occupational Health Sciences Institute) in urban New
Jersey over a two-year period stretching from April 1999 to March 2001. Ten homes with
children 2-5 years of age participated. Each of the homes had a professional "crack and
crevice"-type application of a chlorpyrifos-based formulation at the time of the study, but only
trace amounts of chlorpyrifos were applied in three of the homes. The monitoring period
typically lasted for two weeks with pre- and multiple post-application samples. Sampling was
10
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comprehensive with indoor air, deposition coupons, surface samples (LWW, Lioy-Weisel-
Wainman sampler), toys, hand wipes, urine, air exchange rate, and time activity diary data
collected throughout the study, and additional samples consisting of surface wipes, dermal
wipes, cotton garments, and videotaped activities collected on the second day of the study.
A field laboratory study titled the Distribution of Chlorpyrifos Following a Crack and Crevice
Type Application in the US EPA Indoor Air Quality Research Test House (Test House) was
performed in collaboration with the National Risk Management Research Laboratory (NRMRL).
The Test House is an unoccupied three-bedroom house in Gary, NC. The study investigated the
translocation of chlorpyrifos and the spatial and temporal variability of chlorpyrifos levels in air
and on surfaces following a professional "crack and crevice"-type application onto the floor and
cabinetry of a kitchen. Samples included air, polyurethane foam (PUF) roller, carpet sections,
CIS surface press, and surface wipes from multiple rooms. Samples were collected pre-
application and on days 1, 3, 7, 14 and 21 post-application.
The Pilot Study Examining Translocation Pathways Following a Granular Application of
Diazinon to Residential Lawns (PET) was performed during spring 2001 in six residential homes
within a 50-mile radius of Durham, NC. Measurements were performed at homes where a
homeowner applied a turf application of a granular formulation of diazinon. Sampling included
indoor air (multiple rooms), PUF roller (outdoor and indoor), soil, doormat, high-volume small
surface sampler (HVS3), dermal surrogate (cotton gloves), urine (adult and child), dog fur
clippings, dog paw wipes, dog blood, and videotaping (15-min). Samples were collected pre-
application and 1, 2, 4 and 8 days post-application. A feasibility study was also performed in a
single home. The study focused on pesticide translocation and exposure pathways.
The Dietary Intake of Young Children (DIYC) study was a small observational field study in
collaboration with RTI. It included three homes where diazinon had been applied (two homes
with commercial crack and crevice applications and one home with non-professional application)
and took place between November 1999 and January 2000 (fall and winter). Collected samples
included indoor air, outdoor air, surface wipes, hand wipes, surface press, food press, food
samples, PUF roller, entry wipe, and urine. A primary goal of the study was to evaluate the
potential for exposure to pesticides due to food preparation and handling in the home.
The Feasibility of the Macroactivity Approach to Assess Dermal Exposure (Daycare) study was
another collaboration with RTI (Cohen Hubal et a/., 2006). In this field study, nine day care
centers were identified that reported routine pesticide applications as part of the center's pest
control program. In each daycare, screening sampling was conducted to evaluate the distribution
of transferable pesticide residues on floor surfaces in the area where children spent the most
time. One daycare was selected for more intensive monitoring during the summer of 2001,
following a series of regularly scheduled (monthly) applications. Surface sampling and
videotaping of activities were conducted simultaneously with dermal surrogate (cotton garment)
sampling to calculate dermal transfer coefficients.
The Characterizing Pesticide Residue Transfer Efficiencies (Transfer) studies evaluated
parameters that are believed to affect residue transfer from surface-to-skin, skin-to-object, skin-
to-mouth, and object-to-mouth. The collaboration with Battelle was a series of controlled
laboratory studies using fluorescent tracers as surrogates for pesticide residues. The protocol
11
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involved applying fluorescent tracers to surfaces of interest as a residue at levels typical of
residential pesticide applications, and then conducting controlled transfer experiments varying
six parameters in a systematic fashion. Repetitive contacts with contaminated surfaces were
used to measure the following transfers: hand to clean surface, hand to washing solution, and
hand to mouth. In the mouthing trials, mouthing was simulated using saliva-moistened PUF
material to measure mass of tracer transferred. Laboratory evaluations were performed to relate
transfer of tracer to transfer of pesticides (Ivancic et a/., 2004; Cohen Hubal et a/., 2005).
The Food Transfer Studies were controlled laboratory experiments investigating pesticide
transfer from household surfaces to foods and evaluating factors that have been identified as
important, including surface type, duration of contact, surface loading, and contact pressure
(applied force). Organophosphate, pyrethroid, and pyrazole insecticides were applied onto
various household surfaces using a customized spray chamber. Pesticide transfer efficiencies
were measured for three different foods, with standardized surface contact areas. Amounts of
pesticide residue transferred to foods were compared to the amounts removed using surface
wipes. Transfer efficiency (TE) was defined as the amount of pesticide recovered from the food
item divided by the pesticide concentration or loading level.
1.8 Exposure and Dose Models
It is neither within the scope nor the intention of this report to provide a detailed discussion of
the exposure and dose models that have been developed using these data or applied to these data.
However, since human exposure research progresses through an iterative series of models and
measurements, it is often necessary to refer to these models. Models are constructed using
current knowledge and are subsequently used to identify areas of greatest uncertainty. Modeled
results are used to direct the focus of the measurement studies to address those identified
uncertainties. As newly collected data yields new knowledge, models are refined and the entire
process repeats. At each iteration, real-world data replace default assumptions to produce more
accurate assessments of exposure and risk. Throughout this document models are mentioned.
"Algorithms" are the set of deterministic mathematical expressions developed in the Draft
Protocol for Measuring Children's Non-Occupational Exposure to Pesticides by all Relevant
Pathways (Berry et a/., 2001) to assess exposure by each route as a function of concentration and
various exposure factors. The Stochastic Human Exposure and Dose Simulation (SHEDS)
model (Zartarian et a/., 2000) is a physically-based, probabilistic model that predicts multimedia/
multipathway exposures and doses incurred eating contaminated foods, inhaling contaminated
air, touching contaminated surfaces, and ingesting residues from hand- or object-to-mouth
activities. It combines information on pesticide usage, human activities, environmental concen-
trations, and exposure and dose factors using Monte Carlo methods. The Exposure Related Dose
Estimating Model (ERDEM) (Blancato et a/., 2004) is a physiologically-based pharmacokinetic
(PBPK) model used to make reliable estimates of the chemical dose to organs of animals or
humans. It solves a system of differential equations that describes the organ system, directly
addressing the uncertainties of making route-to-route, low-to-high exposure, and species-to-
species extrapolations when there are exposures to one or to multiple chemicals. The Children's
Dietary Intake Model (CDIM) (Hu etal., 2004) estimates total dietary exposure of children to
chemical contaminants by accounting for excess dietary exposures caused by chemical
contaminant transfer from surfaces and/or hands to foods prior to consumption.
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2.0 PESTICIDE USE PATTERNS
Very limited data are available to EPA researchers on what pesticides are currently being used in
non-occupational environments, where they are being used, and the frequency of use. The EPA
has not conducted a large scale survey to collect data on pesticide use patterns in the U.S. since
1990, but use patterns are believed to have substantially changed since that time. The children's
observational studies described in this report collected information on household pesticide use as
ancillary information that could be used to address this serious data gap. Despite the limited
coverage of geographic regions, a relatively small number of study participants, and the general
lack of knowledge about the active ingredients in brand name products on the part of consumers,
valuable information was obtained. The NERL studies described in this section covered a period
from 1997 to 2001. The indoor residential use of chlorpyrifos was cancelled while data
collection was still ongoing in several studies (JAX, CCC, and CTEPP).
The pesticides available to consumers or professionals for use in residential settings have
changed over time. By the late 1980s the use of most organochlorine pesticides (e.g., DDT,
chlordane, dieldrin, and heptachlor) was severely restricted in the U.S. The organophosphate
(OP) insecticides (e.g., malathion, chlorpyrifos, and diazinon), appealing for their high insect
toxicity, low costs, and low likelihood of pest resistance, quickly filled the void and became the
pesticides of choice for both consumers and professional pest control operators (Karalliedde et
a/., 2001). The popularity of pyrethroid insecticides increased throughout the 1990s because of
the following favorable properties: higher insecticidal toxicity, lower mammalian toxicity, and
more rapid environmental degradation (Baker et al, 2004). Passage of the Food Quality
Protection Act of 1996 led the EPA to consider aggregate childhood pesticide exposure. The
OPs were the first class of pesticides whose tolerances were reassessed, leading to withdrawal of
the registrations for indoor applications of chlorpyrifos and diazinon in 2001 and 2002,
respectively, because of concern regarding the risk to children. Consequently, pyrethroids have
become the leading residential insecticides. While household use of diazinon and chlorpyrifos is
now restricted, these and other OPs are still widely used in agriculture, and some structural uses
for chlorpyrifos, including the treatment of house foundations, are still approved.
2.1 Sources of Information
Important sources of information on pesticide use patterns in non-occupational environments
include Market Estimates from EPA's Office of Pesticide Programs (US EPA, 2004), national
pesticide usage surveys, the Residential Exposure Joint Venture (REJV), the National Health and
Nutrition Examination Survey (NHANES), and published scientific literature.
The Office of Pesticide Programs uses proprietary data sources in producing "Market Estimates"
of pesticide sales and use in various market sectors. According to their estimates, the annual
amount of insecticide active ingredients used in the home and garden sector declined from 24
million pounds in 1982, to less than 13 million pounds in 1988. Although the figure rose to 17
million pounds between 1998 and 2001, it still represents a significant decline from the early
1980s. In contrast, the amount of herbicides applied steadily increased over the same period,
nearly doubling from 37 million pounds in 1982 to 71 million pounds in 2001 (US EPA, 2004)
13
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as lawn coverage increased. In 2001, insecticides comprised nearly 60% and herbicides nearly
30% of the home and garden sector expenditures (US EPA, 2004).
The REJV is a program administered by eight pesticide registrants and is designed to provide
home pesticide usage information critical for risk assessments on individual active ingredients as
well as aggregate and cumulative risk assessments. Pesticide use by over 100,000 households in
nine regions of the U.S. is recorded, with a year-long monthly diary of all residential pesticide
applications in more than 4000 households. EPA expects to use the results of this
comprehensive pesticide use survey to refine or replace many of its residential exposure default
assumptions. Access to REJV results is restricted as confidential business information, thus only
very limited data are publicly available.
Results from two other national surveys are available: the National Household Pesticide Usage
Study (US EPA, 1980; Savage et a/., 1981) and the National Home and Garden Pesticide Use
Survey (US EPA 1992). The National Household Pesticide Usage Study (1976-1977) found that
91% of the more than 8200 households surveyed reported using pesticides in their home, garden,
or yard. According to the slightly more recent National Home and Garden Pesticide Use Survey
(1990), 75% of American households reported using insecticides. These surveys, it should be
noted, are old and the results are not considered relevant to current pesticide use patterns.
NHANES is an ongoing assessment of the exposure of the U.S. population to environmental
chemicals. Beginning with the 1999-2000 cycle, the interview included, at the request of EPA,
questions on pesticide applications performed in the past month. According to the most recent
survey (2001-2002), 18% of households used insecticides inside the home within the past month,
nearly 40% of which were professional treatments. Of households with private yards, 20%
reported pesticide applications in the yard during the month, roughly 36% of which were
professional treatments. NHANES does not report results by region or by season.
Studies in the open literature can also help to identify pesticide use patterns. Davis et al. (1992),
Bass et al. (2001), Curwin et al. (2002), Freeman et al. (2004), and Carlton et al. (2004) address
pesticide use patterns in various geographic locations within the U.S., including Missouri,
Arizona, Iowa, Texas, and New York.
A study conducted in Missouri from June 1989 to March 1990 using telephone interviews (Davis
et al., 1992) examined pesticide use in the home, garden, and yard. Nearly all 238 families
(98%) used pesticides at least one time per year, and two-thirds used pesticides more than five
times per year. Pesticides were most commonly used inside the home (80%), followed by in the
yard (57%). Flea collars were the most popular pest control product (50%). Diazinon and
carbaryl were identified as the two most commonly used active ingredients at that time.
The community-based survey conducted by Bass et al. (2001) in Douglas, Arizona in 1999
identified pesticides used in the home, use and storage locations, and disposal methods. All
(100%) of the 107 randomly chosen study participants reported using pesticides in the six
months prior to the survey, although only 75% reported pest problems. Over 30% used a
professional exterminator. A total of 148 pesticide products, representing more than 50 unique
active ingredients, were catalogued (1.4 products per home). The synergist piperonyl butoxide
14
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(34%) was most common, followed by pyrethrins (24%), permethrin (18%), allethrin (17%),
diazinon (16%), and boric acid (13%). The majority of the pesticides were stored inside the
house (70%), typically in the kitchen (45%).
Curwin et al. (2002) investigated the differences in pesticide use for 25 farm homes and 25 non-
farm homes in Iowa. The target pesticides included atrazine, metolachlor, acetochlor, alachlor,
2,4-D, glyphosate, and chlorpyrifos. Among the non-farm households, 84% used pesticides in
their homes or on their lawns or gardens. Only 17% of reported residential pesticide use was by
commercial application.
Freeman et al. (2004) examined pesticide use patterns during the summer 2000 and winter 2000-
2001 seasons among families with very young children in a Texas border community. Pesticide
use inside the home showed seasonal variation (82% of homes treated in summer versus 63% in
winter). The primary room treated was the kitchen, and the primary structures treated were the
floors, lower walls, and dish cupboards. The pesticides used were typically pyrethroid
formulations. For nearly all of the pesticides analyzed, no differences were found in pesticide
levels in house dust based on family reports of pesticide use in the home or yard.
Carlton et al. (2004) surveyed stores in New York City, NY in mid-2003 to determine whether
the phase-out of chlorpyrifos and diazinon had been effective and what alternative pesticides
were available. The authors found the phase-out to be more effective for chlorpyrifos than for
diazinon. The summer after chlorpyrifos sales were to have ended, chlorpyrifos-containing
products were found in only 4% of stores that sold pesticides; however, after diazinon sales were
to have ended, 18% of stores surveyed, including 80% of supermarkets, still stocked diazinon-
containing products. Lower toxicity pesticides, including gels, bait stations, and boric acid, were
available in only 69% of the stores and were typically more expensive.
The children's exposure research program collected pesticide use information from homes and
daycare centers in the MNCPES, JAX, CTEPP, CCC, and Daycare studies. Information on
collection methods is available in Table 2.1. In the context of this report, pesticide use patterns
include application frequency, locations, types, methods and active ingredients, as well as
pesticides identified in inventories and detected in screenings. The following are highlights of
the data collected on pesticide use patterns in these studies. A thorough discussion of MNCPES
storage and use patterns is found in Adgate et al. (2000).
15
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Table 2.1 Pesticides use information collection methods.
Study
MNCPES
CTEPP
CCC
JAX
Day care
Year
1997
2000-
2001
2001
2001
2000
Setting
Residence
Residence and
Day care
Center
Day care
Center
Residence
Day care
Center
Inventory
Brand name, type, EPA
registration number, use in
past year.
None
None
Brand name, type, EPA
registration number.
Use in past 6 months, use
frequency, use location, and
targeted pest noted for each
product.
None
Questionnaire
Baseline usage (past year) by
participant recollection. Recent
use (past week and during
monitoring period).
Baseline usage (ever) of
insecticides, herbicides,
fungicides, or shampoos. Recent
use (past week) of any pesticide.
Usage frequency (categories)
and locations for specific active
ingredients. Questionnaire
administered to Center Director
or professional applicator.
Usage frequency (categories),
locations, application methods,
and anticipated future use.
Specific active ingredient
verified by professional
applicator.
Screening
Wipes
No
No
Yes
Yes
Yes
16
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2.2 Application Frequency
The frequency of pesticide application, typically over the past month or year, is generally
gathered through questionnaires. Although there is little supporting empirical evidence, it is
believed that the frequency of application, along with the form and chemical properties of the
pesticide, is an important determinant of indoor air and surface concentrations. It is assumed that
residue levels within a residence will rise with increasing pesticide application frequency.
Conversely, infrequent pesticide application is assumed to decrease the likelihood of measuring
pesticide residues. Arguably, the more frequently pesticide applications occur, the more likely
the occupant is to have contact with pesticide residue.
As presented in Table 2.2, about 20% of study participants in Jacksonville, FL (JAX)
reported using pesticides in the past seven days (August to October 2001) compared to
14% in CTEPP-NC (July 2000 to March 2001), 13% in CTEPP-OH (April to November
2001), and only 10% in Minnesota (MNCPES) (May to August 1997). This provides
some evidence of a pattern of higher application frequencies in warmer climates. The
North Carolina study was the only one to include winter months; the percentage would
likely be higher if winter months were excluded.
About the same proportion (unweighted) of participants that used pesticides in the past
month (or planned to use them in the next month) in JAX (51%), used them in the past
six months in MNCPES (52%). The percentage of JAX participants is substantially
higher than 18-23% reporting insecticide use in the past month in NHANES (Table 2.2).
Differences according to geographical region become more evident in the CTEPP studies
(Table 2.3) when focusing on insecticides and rodenticides, as 74% of the participants in
warmer climate North Carolina reported using insecticides or rodenticides compared to
only 51% in colder climate Ohio.
In Minnesota (MNCPES), 88% of the participants used pesticides in the past year,
slightly more than the 84% reported by Curwin et al. (2002) in Iowa but less than the
98% reported by Davis et al. (1992) in Missouri and the 100% reported by Bass et al.
(2001) in Arizona.
In the CCC study, 74% of the facilities reported application of pesticides in the last year
(63% reported interior and 42% reported exterior applications), and 7% were unsure if
any application occurred. Up to 107 pesticide applications per year were reported.
About a third of the interior and a quarter of the exterior applications in the nationwide
CCC study were performed on a monthly basis. In the Daycare study, monthly or more
frequent pesticide applications were anecdotally found to be standard practice in the
Raleigh-Durham area of North Carolina.
17
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Table 2.2 Proportion (unweighted) of participants reporting pesticide use by study. NHANES
participant responses are included for comparison.
Study
CTEPP-NC
CTEPP-OH
JAX
MNCPES
NHANES 99-00
NHANES 01-02
Use within the past
seven days
14%
13%
20%
10% b
~
~
Use within the past
one month
a
~
51%
-
23% c
18%c
Use within the past
six months
-
~
~
52%
~
~
a Information not available
b Recruited households
0 Restricted to use inside of home
Table 2.3 The proportion of CTEPP participants reporting use of four types of pesticides.
Type of Pesticide
Herbicides
Insecticides / Rodenticides
Fungicides
Shampoos / Lotions
North Carolina
38%
74%
6%
8%
Ohio
50%
51%
4%
9%
18
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2.3 Application Locations
Although applied pesticides are redistributed throughout a home following an application, a
concentration gradient exists with higher concentrations in the application room and lower
concentrations in more distant rooms (Stout and Mason, 2003). Since residential applications
may be performed by someone other than the occupant (e.g., professional pest control service,
gardener, lawn service, or property management), the occupant may not know which locations
were treated.
In JAX, 58% reported treating all rooms in the home, and 15% reported treating just the
kitchen.
The most commonly treated room in the CCC study was the kitchen (62%), followed by
the bathroom (52%) (Figure 2.1). All rooms were treated in 23% of the centers.
Areas treated by professional crack and crevice applications in CPPAES represented 93%
of the homes' living areas.
purpose
room
Room
Figure 2.1 Weighted percentage of child care centers reporting treatment of various rooms in the
Child Care Centers (CCC) study.
19
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2.4 Application Types and Methods
The three common types of pesticide applications in the non-occupational environment are
broadcast, total release aerosol, and crack-and-crevice. A broadcast application spreads
insecticide onto broad surfaces, typically large sections of walls, floors, ceilings, or in and
around trash containers (Rust etal., 1995). Total release aerosols, also known as "foggers" or
"bug bombs," contain propellants that release their contents at once to fumigate a large area.
Alternatively, a crack-and-crevice application is the application of small amounts of insecticide
into areas where pests typically harbor or enter a building. Cracks and crevices are commonly
found between cabinets and walls, at expansion joints, and between equipment and floors (Rust
et a/., 1995). Crack and crevice type applications, which usually produce lower airborne
concentrations and surface loadings than broadcast or total release type applications, are favored
by professional pest control services.
Method of pesticide application (as differentiated from "type" of application) refers to the
equipment or product form used, and may include aerosol sprayer, hand pump sprayer, hose end
sprayer, spritz sprayer, hand trigger sprayer, liquid, fogger, gel, granules/dust/powder/pellets,
lotion, shampoo, bait station/trap, candle/coil, fly strip, pet collar, and spot-on pet treatment.
Only very limited information on application type and method was collected in any of the
field study questionnaires.
In CCC, 36% of the interior applications were reported by the center directors as crack
and crevice, and only 2% were reported as broadcast. In the Daycare study, all observed
pesticide applications were crack and crevice.
The most common application methods reported in JAX were as follows: 37% hand
pump sprayer, 24% aerosol can, 3% fogger, and 3% bait.
Applications in JAX were more likely to be performed by the respondent or respondent's
family member (41%) than by a professional service (35%). These results are similar to
NHANES 01-02, where 66% of the survey respondents reported non-professional
treatments compared to professional treatments that were reported by 40% of the
respondents. These results are also similar to the survey by Bass et al. (2001) in Douglas,
Arizona, where 30% used professional services.
2.5 Pesticides Identified in Inventories, Records and Wipe Samples
Pesticide products were found in 86% of the 36 homes inventoried in the JAX study
(Table 2.4), with up to three products per household. Pyrethroids were the most common
active ingredient (67% of homes), primarily cypermethrin (25%) and allethrin (12%),
followed by imiprothrin, pyrethrins, and tralomethrin (all 14%). Only one
organophosphate insecticide (diazinon) and one insect repellent (DEBT) were found.
The most commonly inventoried pyrethroids in JAX (Table 2.4) corresponded well with
commonly reported pyrethroids in the Residential Exposure Joint Venture (Table 2.5).
Cataloguing of pesticides in the CCC study (Table 2.6) gave results similar to JAX, with
pyrethroid products most commonly identified (second only to products with unknown
20
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active ingredients).
The finding of 145 application events (Table 2.6) with unidentified active ingredients in
the CCC study suggests that tracking of pesticide use in and around day care facilities
may require improved recordkeeping.
As reported in Adgate et al. (2000), pesticide products were found in 97% (weighted) of
the MNCPES households. The weighted mean number of pesticide products used per
household was 3.1. Participants reported that fewer than 25% of the pesticides
inventoried in their homes were used during the past year.
In MNCPES, DEET-containing products were used in 47% of the homes during the last
year (Table 2.7).
Repellents, pyrethrins and pyrethroids, organophosphates, chlorophenoxy herbicides, and
carbamates were present in more than 20% of the MNCPES households (Table 2.7).
In the Daycare study, professional pest control services applied pyrethroid or pyrethrin
pesticides in six of the eight facilities (data not presented). Esfenvalerate was applied in
two facilities while cyhalothrin, pyrethrins, cypermethrin, and tralomethrins were each
used in one.
Cypermethrin, c/'s-permethrin, and ^ram'-permethrin were detected in over 80% of the
surface wipe samples collected in 46 homes in JAX (Table 2.8), consistent with the
pesticide inventories. Chlorpyrifos and diazinon, although not identified in the
inventories, were present in 89% and 91%, respectively, of the surface wipe samples.
Permethrin and cypermethrin were the most frequently detected pyrethroid pesticides in
both JAX (homes) and CCC (childcare centers) (Table 2.8). Chlorpyrifos and diazinon
were the most frequently detected OPs, at frequencies comparable to permethrin.
As of 2001, the synthetic pyrethroids appeared to be the most frequently used insecticides
for indoor applications in homes and child care centers. It is anticipated that their use has
become even more common since the cancellation of indoor use registrations of
Chlorpyrifos (2001) and diazinon (2002).
2.6 Demographic Factors Influencing Applications
As reported by Adgate et a/., (2000), there were no statistically significant differences in
the weighted total number of products found or reportedly used in MNCPES based on
either population density (urban versus non-urban households) or other socio-
demographic factors including race, ethnicity, home type, income, and level of education.
Chi square analysis of CTEPP data (not presented) found no association between having
applied pesticides within the past week and either income class or urban/rural status.
21
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Table 2.4 Pesticides inventoried in 36 households in Jacksonville, FL (JAX) in fall 2001.
Active Ingredient
Cypermethrin
Allethrin
Pyrethrins
Imiprothrin
Tralomethrin
MGK 264 a
Permethrin
Fipronil
Piperonyl butoxide
Hydramethylnon
Tetramethrin
Cyfluthrin
Esfenvalerate
Prallethrin
Bifenthrin
DEBT
Diazinon
Pesticide Class
Pyrethrins/Pyrethroids
Pyrethrins/Pyrethroids
Pyrethrins/Pyrethroids
Pyrethrins/Pyrethroids
Pyrethrins/Pyrethroids
Synergist
Pyrethrins/Pyrethroids
Phenylpyrazole
Synergist
Aminohydrazone
Pyrethrins/Pyrethroids
Pyrethrins/Pyrethroids
Pyrethrins/Pyrethroids
Pyrethrins/Pyrethroids
Pyrethrins/Pyrethroids
Repellent
Organophosphate
Number of Homes Where
Found (% of Homes)
9 (25%)
8 (22%)
5 (14%)
5 (14%)
5 (14%)
4(11%)
4(11%)
4(11%)
4(11%)
3 (8%)
3 (8%)
2 (6%)
2 (6%)
2 (6%)
1 (6%)
1 (6%)
1 (6%)
' N-octyl bicycloheptene dicarboximide
Table 2.5 Most commonly applied pyrethroids in 1217 households with complete 12 month
REJV survey data, as reported by Ozkaynak (2005).
Pyrethroid Pesticide
Permethrin
Pyrethrins
Piperonyl Butoxide
Allethrin
Tetramethrin
Phenothrin
Tralomethrin
Cypermethrin
Resmethrin
Bifenthrin
Cyfluthrin
Fenvalerate
Esfenvalerate
Deltamethrin
Prallethrin
Cyhalothrin
Number of Homes Where
Applied (% of Homes)
518(43%)
472 (39%)
461 (38%)
437 (36%)
342 (28%)
293 (24%)
279 (23%)
163 (13%)
106 (9%)
99 (8%)
46 (4%)
37 (3%)
25 (2%)
22 (2%)
13 (1%)
4 (<1%)
22
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Table 2.6 Number of pesticide products applied during one year (2001) in 168 child care centers
(CCC), as reported by the center directors and/or professional applicators.
Pesticide Class or Type
Unknown
Pyrethroids
Phenyl pyrazole or unclassified insecticide
Pesticide mix
Fungicide/insecticide
Organophosphate
Glueboard/Mouse traps
Carbamates
Juvenile hormone mimic insecticide
Coumarin rodenticides
Herbicides
Insecticides
Unclassified acaricide
Unclassified insecticide
Biopesticides
Pheromone
Phosphoramidothioate acaricide
Rodenticides
Number of Products Applied in Past Year
(Unweighted % of All Products)
145 (39%)
93 (25%)
44 (12%)
22 (6%)
20 (5%)
10 (3%)
7 (2%)
6 (2%)
6 (2%)
5 (1%)
3 (1%)
3 (1%)
3 (1%)
3 (1%)
2 (1%)
1 (<1%)
1 (<1%)
1 (<1%)
Table 2.7 Pesticides inventoried and used in 308 households in Minnesota (MNCPES) in
summer 1997 (adapted from Adgate et al, 2000).
Active Ingredient
DEBT
Piperonyl butoxide
Pyrethrins
MCPA
Permethrin
Chlorpyrifos
Propoxur
MGK2643
Allethrin
2,4-D
Diazinon
Glyphosoate
Tetramethrin
Resmethrin
Carbaryl
Pesticide Class
Repellent
Synergist
Pyrethrins/Pyrethroids
Chlorphenoxy herbicide
Pyrethrins/Pyrethroids
Organophosphate
Carbamate
Synergist
Pyrethrins/Pyrethroids
Chlorphenoxy herbicide
Organophosphate
Aminophosphate
Pyrethrins/Pyrethroids
Pyrethrins/Pyrethroids
Carbamate
Homes Where Found
(Weighted Percent)
196 (58%)
152 (45%)
147 (43%)
107 (35%)
93 (35%)
89 (29%)
84 (25%)
83 (25%)
81 (24%)
74 (23%)
65 (18%)
62 (18%)
62 (18%)
60 (20%)
50 (14%)
Homes Where Used
in the Past Year
(Weighted Percent)
162 (47%)
91 (25%)
88 (25%)
55 (17%)
65 (15%)
55 (17%)
53 (17%)
43 (12%)
49 (13%)
37(11%)
37(11%)
37 (12%)
32 (8.5%)
24(8.1%)
24 (5.4%)
1 N-octyl bicycloheptene dicarboximide
23
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Table 2.8 Detection frequencies of target analytes in soil and wipe samples in the CCC study
(weighted) and in screening wipe samples collected in JAX (unweighted).
Compound
CCC
% Detect in
Soil Samples
% Detect in Floor
Wipes
% Detect in
Surface Wipes
JAX
% Detect in
Surface Wipes
PYRETHROIDS
c/5-Allethrin
/raws-Allethrin
Bifenthrin
Cyfluthrin
lambda-Cyhaloihnn
Cypermethrin
Delta/Tralomethrin
Esfenvalerate
c/5-Permethrin
/raws-Permethrin
Resmethrin
Sumithrin
Tetramethrin
5
5
14
7
6
8
5
9
12
15
5
5
5
2
2
5
7
7
23
2
6
63
64
3
2
2
0
0
4
1
5
9
0
0
48
64
6
1
0
22
22
20
20
9
80
15
30
89
87
0
4
13
ORGANOPHOSPHATES
Acephate
Azinphos methyl
Chlorpyrifos
Chlorpyrifos oxon
Demeton S
Diazinon
Diazinon oxon
Dichlorvos
Dimethoate
Disulfoton
Ethion
Ethyl parathion
Fonofos
Malathion
Malathion oxon
Methamidophos
Methidathion
Methyl parathion
c/5-Mevinphos
/raws-Mevinpho s
Naled
Phosmet
50
15
21
11
11
19
13
11
11
11
11
11
12
12
11
11
11
11
11
11
11
11
3
1
67
1
0
53
17
0
1
0
1
1
0
18
0
2
1
0
21
5
0
2
0
0
76
1
0
43
8
0
0
0
0
0
0
5
0
1
1
0
7
0
0
0
7
2
89
0
0
91
17
2
0
0
2
0
0
20
0
0
0
0
7
4
0
4
OTHER PRODUCTS
Fipronil
Piperonyl butoxide
11
12
8
23
10
11
7
50
24
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3.0 AIR CONCENTRATION MEASUREMENTS
3.1 Introduction and Data Availability
Children are exposed to residential pesticides via the ingestion, dermal, and inhalation routes. Of
these routes, inhalation is the best characterized and requires measurements that are simple to
collect in field studies. Estimating absorption via inhalation relies on measured airborne
chemical concentrations and on relatively few default exposure factor assumptions, such as the
inhalation rate and time spent in specific locations. Since indoor pesticide concentrations are
typically higher than outdoor concentrations, and since young children spend the majority of
their time indoors, indoor concentrations account for the bulk of their inhalation exposure.
Absorption via the inhalation pathway involves the uptake of vapors and particle-bound residues
present in the air. It is generally assumed that inhaled vapors will be readily absorbed across the
alveolar membrane into the bloodstream (at least for soluble compounds). Particle-bound
residue may vary in size and composition, both of which may influence thoracic penetration and
affect absorption. Inhaled particle-bound contaminants trapped in upper airway (nasal and upper
lung) mucosa may also be subsequently ingested.
The methods for measuring of airborne pesticide concentrations are well-developed and easily
implemented indoors and outdoors using stationary or personal samplers. The methods involve
collecting gases and/or particle-bound residues onto filters and sorbent media (the two are
combined so that no distinction is made between gases and particle-bound residues). Stationary
samplers are typically placed adjacent to treated areas and/or in the location where the participant
spends the most time. Samplers may be placed at several locations throughout the home to
investigate the spatial distribution of pesticides. Stationary samplers are located at specified
heights above the floor to represent the assumed breathing area of the study participants.
Personal samplers are worn by the study participants near the breathing zone. Either type of
sampler may be modified with a size selective inlet to exclude specific particle size fractions.
Sampling media vary but often consist of a pre-filter in tandem with a sorbent composed of
polyurethane foam (PUF) or polymeric resin beads (e.g., XAD).
The sampling approaches and methods for each study are described in Table 3.1. Since air
sampling techniques are fairly standardized, the methods are consistent across studies. In the
large observational field studies, air samples were collected over multiple days for reasons that
included reducing measurement error due to day-to-day variability, improving detection limits,
and reducing costs associated with changing and analyzing filters. The smaller, focused studies
typically employed multiple, consecutive 24-hour sampling periods to capture temporal
variability. Personal sampling was attempted in only one study, MNCPES, but compliance
issues were noted.
3.2 Pesticide Presence
All pesticides included in this report have been used in residential settings. Because of the
potentially long persistence of some pesticides in the indoor environment (Gurunathan et al,
1998), they may be detected even in the absence of a recent application. Detection frequencies
for indoor and outdoor samples are presented graphically in Figure 3.1. While detection
25
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frequency corresponds inversely to the limit of detection (LOD), the LOD for each compound is
relatively consistent across the large observational field studies. The exception to this is the
NHEXAS-Arizona study, which employed a collection method with a relatively small sample
volume, resulting in a higher LOD. The LODs for each pesticide by study are presented in Table
3.2.
Detection limits (Table 3.2) varied by as much as an order of magnitude across studies.
Within studies, detection limits were similar for organophosphate and pyrethroid
insecticides. Detection limits are influenced by sample volume (Table 3.1). For
example, the much lower detection limits for chlorpyrifos and diazinon in MNCPES
compared to NHEXAS-AZ reflects the much larger volume sampled in MNCPES.
The compounds most frequently detected in indoor air (Figure 3.1) were the
organophosphate (OP) insecticides chlorpyrifos, (typically > 90%) and diazinon
(typically > 75%), followed by the pyrethroid insecticide permethrin (typically > 50%).
The insecticides most frequently detected in outdoor air (Figure 3.1) were also
chlorpyrifos and diazinon, but the detection frequencies were lower and more variable
across studies.
Chlorpyrifos was detected at a high frequency (Figure 3.1) even in those studies
conducted after its indoor residential use was restricted (JAX and CHAMACOS).
The pesticide degradation products of chlorpyrifos and diazinon, TCPy and IMP,
respectively, were frequently detected in air samples collected in CTEPP (Figure 3.1);
none of the other studies included these as target analytes.
26
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Table 3.1 Summary of air sample collection methods.
Study
NHEXAS-AZ
MNCPES
CTEPP
JAX2001
CHAMACOS
CPPAES
Test House
PET Pilot Study
DIYC
Samples
Collected
Indoor
Personal
Indoor
Outdoor
Indoor
Outdoor
Indoor
Outdoor
Indoor
Outdoor
Indoor
Indoor
Indoor
Indoor
Outdoor
Cohort
Size
14
70
97
52
257
9
20
10
1
6
3
Sampling
Location
Home
Home
Home and
Daycare
Home
Home
Home
Test House
Home
Home
Sampling
Device
Pumps w/ 10 |im
inlet, PUT and
Teflon-coated
glass filters
Pumps w/ XAD
cartridge and
quartz filter
Pumps w/ 10 |im
inlet, quartz fiber
filter and XAD-2
cartridge
Constant-flow
battery powered
pump w/ PUT
cartridge
Sampling pump
with PUF cartridge
Harvard Sampler
w/PM10 inlet,
cotton filter
impregnated w/
activated carbon
Low volume pump
w/PUF
Low volume pump
w/PUF
Pump w/XAD
Device Details
Intermittent
sampling (total of
12 h over 3 d)
Backpack carrying
case for personal,
sound-proof
enclosure
Indoor: Styrofoam
box w/ cooling
fan; Outdoor:
plastic dog house.
75 cm height.
Breathing-zone
height indoor, 1.5
m height outdoor
Tamper-resistant
box
Placed in room
most frequented
by child, approx 1
m high.
Multiple rooms
Living room and
child's bedroom
Placed in room
most frequented
by child,
Sample Volume
Approx 3 m3 (4
L/min for 12 hr)
Approx 10.8m3
(1.25 L/min for
144 hr)
Approx 12 m3 (4
L/min for 48 hr)
Approx 5. 5 m3
(3. 8 L/min for
24h)
Approx. 3.6m3
(2. 5 L/min for 24
hr)
Approx. 14m3
(24h) and 29 m3
(48h)
Approx 5m3 (3.5
L/min for 24 hr)
Approx 5m3 (3.5
L/min for 24 hr)
Approx. 11.5 m3
(8 L/min for 24 hr)
Collection
Frequency
Integrated 3-day
monitoring period
Continuous, Days
1-7, integrated
One 48-hr sample
One 24-hr sample
One 24-hr sample
Four 24-hr
samples on days 0-
3; four 48-hr
samples days 3-11
Time series over
21 days
24-hr samples:
Pre-application
and days 1,2, 4, &
8 post-application
One pre- and six
post-application
measurements
Collection After
Pesticide Use
No
No
No
Yes, indoor
No
Yes, indoor
Yes
Yes, lawn
application
Yes, indoor (2
professional, 1
resident)
Relevant Analytes
Chlorpyrifos,
Diazinon, Malathion
Chlorpyrifos,
Diazinon,
Malathion, Atrazine
OPs & Pyrethroids
incl. Chlorpyrifos,
Diazinon, and
Permethrin
OPs & Pyrethroids
incl. Chlorpyrifos,
Diazinon, and
Permethrin
OPs & Pyrethroids
incl. Chlorpyrifos,
Diazinon, and
Permethrin
Chlorpyrifos
Chlorpyrifos
Diazinon
Diazinon
27
-------
Table 3.2 Limits of detection (ng/m3) for air samples by compound and study.
Compound
NHEXAS-AZ
MNCPES
CTEPP NC
CTEPP OH
JAX
CHAMACOS
CPPAES
DIYC
PET
Chlorpyrifos
3.2
0.10
0.09
0.09
1.0
0.3
2.0
-
-
Diazinon
2.1
0.10
0.09
0.09
0.4
0.3
-
1.2
1.0
cis-
Permethrin
a
0.09
0.09
0.39
1.0
0.6
-
-
-
trans-
Permethrin
-
0.09
0.09
0.33
1.0
0.6
-
-
-
Cyfluthrin
-
-
0.87
0.87
1.2
7.0
-
-
-
TCPy
-
-
0.09
0.09
-
~
-
-
-
IMP
-
-
0.09
0.09
-
~
-
-
-
"Blank cells (--) indicate that the pesticide or metabolite was not measured in the study.
28
-------
Detection Frequency in Indoor Air
90- 1 M
;
Frequency (%)
Ol O> -J 0
^ ฐ ฐ c
| 40- i
s so- ;:
ฐ M
10- !
| I I
i ! i
! '
i ' I
! i
i \ i
i '' I
; ; :
| : i
i '' ]-
! ' :
\ ' :
! ', :
i
i
'
i
i
i
1
1
i
i
i
i
'
i
i
i
1
1
i
Chlorpyrifos TCPY Diazinon IMP
^raMNCPES ^E3CTEPP-NC
^^CPPAES ^^ITest House
i
c-Perm t-Perm Cyfluthrin
^^CTEPP-OH
KSSPET IZZ2 DIYC
Detection Frequency in Outdoor Air
100-1
90-
80-
70-
60H
2 so-
01
3 30-
Q
20-
10-
Chlorpyrifos TCPY Diazinon
IMP
c-Perm t-Perm Cyfluthrin
3CTEPP-NC
1CTEPP-OH ^^CHAMACOS ^^ JAX
Figure 3.1 Frequency of detection of pesticides measured in indoor and outdoor air in selected
studies.
29
-------
3.3 Comparisons of Air Concentrations
Previous studies have reported post-application concentrations of semi-volatile pesticides in air
that may reach levels representing considerable exposure by the inhalation route (Byrne et al,
1998; Fenske et al., 1990; Lewis et al., 2001). Low measurable airborne levels have also been
reported even in the absence of a recent application event (Lewis et al., 1994; Whitmore et al.,
1994). Lognormal probability plots and box-and-whisker plots graphically depicting the
(unweighted) measurements of compounds of interest in our studies are presented in Figures 3.2
through 3.5. The median and 95th percentile concentrations are presented in Table 3.3 (complete
summary statistics are presented in Tables A.I through A.7 in Appendix A).
For pesticides measured in indoor and outdoor air, the observed concentrations typically
approximate lognormal distributions, as demonstrated in the lognormal probability plots
in Figures 3.2 and 3.3.
Despite differences in the lengths of the sample collection periods (1 to 7 days), the in-
door chlorpyrifos concentrations observed across the large observational field studies are
similar in their variability, as demonstrated by similar slopes in the probability plot
(Figure 3.2). Similar variability over varying collection periods suggests that air
concentrations are reasonably consistent from day-to-day in the absence of a recent
application.
Comparison of air concentrations across studies in the box-and-whisker plots (Figure 3.4)
finds that, as expected, pesticide concentrations in smaller studies, where measurements
immediately followed an application, are much higher than in the larger observational
field studies; for example, note the high indoor chlorpyrifos levels measured in CPPAES
and the Test House.
Median concentrations are typically an order of magnitude higher indoors than outdoors
(Table 3.3). Two notable exceptions are JAX and CHAMACOS. In the JAX samples,
collected in a community with high year-round pesticide usage, outdoor diazinon and cis-
and ^rara'-permethrin levels are nearly as high as indoor levels. In the CHAMACOS
samples, collected in an agricultural community, median outdoor diazinon levels exceed
indoor levels.
The low pesticide concentrations routinely measured outdoors (notwithstanding the
exceptions noted above) together with the relatively short amount of time that young
children typically spend outdoors suggest that inhalation of outdoor air is not an
important contributor to their aggregate pesticide exposure.
The median indoor concentrations in the large observational field studies are higher for
the organophosphates (OPs) than for the pyrethroids (Figure 3.4). Not only do OPs tend
to have higher vapor pressure, but at the time these studies were conducted, OPs still
dominated the marketplace. Detectable levels of chlorpyrifos and diazinon are likely to
exist for some time after restriction of their indoor uses due continued use of existing
home inventories and reemission from indoor surfaces serving as sinks (such as carpet).
30
-------
In indoor air measured in CTEPP (Figure 3.6), a relationship is evident between
chlorpyrifos and its degradation product TCPy. The same is true for diazinon and its
degradation product IMP. The nearly log-log relationship suggests a power relationship,
and at the median level the degradate is present at about 25 to 30% of the concentration
of its parent. Accordingly, the metabolites/degradates measured in urine may reflect
exposure to both the parent pesticide and the degradate, not just to the parent compound
as is often assumed.
Environmental concentrations of the degradation products were not measured in any of
the small, pilot-scale studies, thus the degradate-to-parent ratio immediately following
application is unknown.
Table 3.3 Median and 95th percentile air concentrations (ng/m3, unweighted) for frequently
detected pesticides.
Study
NHEXAS-AZ
MNCPES
CTEPP-OHC
CTEPP-NCC
JAX
CHAMACOS
CPPAES e
Test House e
PET
DIYC
Location
Indoor
Outdoor
Personal
Indoor
Outdoor
Indoor
Outdoor
Indoor
Outdoor
Indoor
Outdoor
Indoor
Outdoor
Indoor
Indoor
Indoor
Indoor
Chlorpyrifos
P50
3.37
NDb
1.52
1.85
0.10
1.75
0.20
6.07
0.28
20.37
3.77
1.90
0.90
149.0
290.0
-
-
P95
164.7
ND
16.86
30.25
0.19
21.69
1.13
62.22
3.99
84.92
6.62
NAd
NAd
815.6
1000
-
-
Diazinon
P50
5.59
ND
0.28
0.27
0.10
0.97
0.15
2.03
0.09
4.64
3.53
1.80
2.80
4.55
~
45.6
1800
P95
219.6
ND
4.66
8.59
0.22
56.87
1.49
63.66
0.98
28.04
6.76
NAd
NAd
23.88
~
562
4900
c/5-Permethrin
P50
a
-
0.20
0.09
0.09
0.28
0.28
0.41
0.06
0.71
2.13
0.50
0.10
-
~
-
-
P95
-
-
2.07
1.26
0.15
1.63
0.95
7.79
0.47
92.47
2.29
NAd
NAd
-
~
-
-
/raws-Permethrin
P50
-
-
O.09
0.09
0.09
0.23
0.23
0.27
0.06
3.06
2.50
O.10
O.10
-
~
-
-
P95
-
-
1.72
1.26
0.48
1.04
0.66
7.16
0.30
134.3
10.24
NAd
NAd
-
~
-
-
a Blank cells indicate the pesticide was not measured in the study
b ND = not detected
0 CTEPP samples collected at both homes and daycares
d NA = summary statistic not available at time the report was prepared
e Day 1 measurements only, multiple rooms
-------
CHLORPYRIFOS CHLORPYRIFOS
INDOOR NR (ng/m3) OUTDOOR AIR (ng/m3)
1 0000 1
1000 1
100 1
10
1
.1 '
01 "
* *00*
O
LX!
^jpp
**g!iPF^
X
*ฃ>
pv>
J>^
$&*
^
* *
SfeV
I
10000 1
1000 1
100 ]
10 -
1 -
.1 -
ni -
*ฃ
Zt
**
i*'
,^i
Bdra
(^s
,A
*i
s^'
A A A
xx
*ซ**o
<
X
.1.2.51 2 5 10 2030 50 7030 9095 99 99.9 .1.2.51 2 5 ID 2030 50 7080 9095 99 99
Percent Percent
+ + + NHEXAS-AZ
* * * CTEPP-NC HOME
000 CTEPP-OH HOME
DIAZINON
XXX MNCPES + + + NHEXAS-AZ XXX MNCPES
D D D CTEPP-NC DAYCARE * * * CTEPP-NC HOME D D D CTEPP-NC DAYCARE
A A A CTEPP-OH DAYCARE O O O CTEPP-OH HOME A A A CTEPP-OH DAYCARE
DIAZINON
INDOOR AIR (ng/m3) OUTDOOR AIR (ng/m3)
1 0000 1
1000 l
100 1
10
1 ]
.1 l
01 "
>W$
oo
.-ซJ
&HF
X )
+ +
^*
: *T
+ +r-t
P?
S***>
^
.^t
j-JB*5?
PLfj
5sK
jS*
*
*
**.
^
XX X
10000 -
1000 -
100 -i
10 1
1 1
.1 -
m -
i
s*t
fi
-------
1 0000 1
1DOO ]
100 1
10
1
.1 '
.01 -
TRANS-PERMETHRIN
INDOOR NR (ng/m3)
:
1
i
&
^
^
**#
jjpm-
jtT r
&*
r
* *
^ X
oO
r
1.2.51 2 5 10 2030 50 7030 9095 99 99
10000 1
1000 1
100 ]
10 -
1 -
.1 -
.01 -
9
TRANS-PERMETHRIN
OUTDOOR AIR (ng/m3)
n ^
ซ*"**
lฃf
&
<*>ซฃ $
p>*
1.2.51 2 5 ID 2030 50 7080 9095 99 99
Percent Percent
XXX MNCPES * * * CTEPP-NC HOME XXX MNCPES * * * CTEPP-NC HOME
D D D CTEPP-NC DAYCARE O O O CTEPP-OH HOME D D D CTEPP-NC DAYCARE O O O CTEPP-OH HOME
A A A CTEPP-OH DAYCARE A A A CTEPP-OH DAYCARE
1 0000 1
1000 1
100 1
10 -
1 -
.1 ]
.01 -
TCPY
INDOOR NR (ng/m3)
* #*H
*&ฃ&
a^e
i
_J
<ง
fS*
*ggi
&
ort*
tfS**'
IT"
ซKง$0
rf&
>
1.2.51 2 5 10 2030 50 70 SO 9095 99 99
10000 1
1000 ]
100 1
10 -
1 -
.1 1
.01 -
9
TCPY
OUTDOOR AIR (ng/m3)
r?
#*&?
ST:
**&#
ggP
4&
*
N^*ซ
1.2.51 2 5 10 2030 50 7080 9095 99 99
Percent Percent
* * * CTEPP-NC HOME ODD CTEPP-NC DAYCARE * * * CTEPP-NC HOME ODD CTEPP-NC DAYCARE
0 0 0 CTEPP-OH HOME A A A CTEPP-OH DAYCARE O O O CTEPP-OH HOME A A A CTEPP-OH DAYCARE
1 DOOO i
1DOO l
100 1
10 ;
1 1
.1 1
O1
IMP
INDOOR NR (ng/m3)
ซ>ซ*"
A
ntf*
BEf-
**
^
$*r
O
10000 -
1000 1
100 1
10 -
1 1
.1 -
m -
IMP
OUTDOOR AIR (ng/m3)
rfrf
^
^AA
. .
^-gU
. .
A
-ซ
#**"
.
O
.
.1.2.51 2 5 10 2030 50 7080 9095 99 99.9
Percent
.1.2.51 2 5 10 2030 50 7080 9095 99 99.9
Percent
000 CTEPP-OH HOME
A A A CTEPP-OH DAYCARE
000 CTEPP-OH HOME
A A A CTEPP-OH DAYCARE
Figure 3.3 Log probability plots for trans-permethnn, TCPy, and IMP measured in large
observational field studies. Only values above the limit of detection are plotted.
33
-------
CHLORPYRIFOS
INDOOR AIR (ng/m3)
CHLORPYRIFOS
OUTDOOR AIR (ng/m3)
ฃ
CT
O
z
o
10000
1000-
100-
10:
1
0.1
0.01 -
i I I I I I I i i r
AZ MN NC HM NC DC OH HM OH DC JAX CHA CPPAES TEST
I I I I I I
MN NC HM NC DC OH HM OH DC JAX
DIAZINON
INDOOR AIR (ng/n-13)
DIAZINON
OUTDOOR AIR (ng/m3)
ro
E
o
o
10000-i
10DO-!
100-
10-
1 -
0.1 -
0.01 -
T
r
t
:E
]J
T
A
10000-
Irj 1000 T
100-
3งfll ";
0.1 -
0.01 -
: E
i ง E
jO^S
3 B
\ I I I I I I I I
AZ MN NC HM NC DC OH HM OH DC JAX CHA PET DIYC
I I I I
MN NCHM NCDC OH HM OH DC JAX CHA DtfC
CIS-PERMETHRIN
INDOOR AIR (ng/m3)
CIS-PERMETHRIN
OUTDOOR AIR (ng/m3)
o
o
o
10000n
1000
100
10-
1
0.1 -
0.01 -
10
0.1
0.01 -
I I I I
NC DC CH HM OH DC JAX
MN NC HM NC DC OH HM OH DC JAX
Figure 3.4 Indoor and outdoor air concentrations of chlorpyrifos, diazinon, and c/'s-permethrin
measured in selected studies. Legend: AZ = NHEXAS-AZ, MN = MNCPES, NC HM =
CTEPP-NC Home, NC DC = CTEPP-NC Daycare, OH HM = CTEPP-OH Home, OH DC =
CTEPP-OH Daycare, CHA = CHAMACOS, TEST = Test House.
34
-------
TRANS-PERMETHRIN
INDOOR AIR (ng/m3)
TRANS-PERMETHRIN
OUTDOOR AIR (ng/m3)
10000-:
^ 1000-
S 10CH
Z
1 10^
Cฃ
1
Z 1 -
Ld
0 0.1 -
o
0.01 -
[
^
F
t
^
-p
i n
] y
- ฃ
I
F
L
^
10000-
1000-
100 ]
ifl;
] T i!
0.1 -
0.01 -
up
T I T
L ^ ^
\ I I I
MN NC HM NC DC OH HM OH DC JAX CHA
i i i i i r
MN NC HM NC DC OH HM OH DC JAX CHA
TCPY
INDOOR AIR (ng/m3)
TCPY
OUTDOOR AIR (ng/m3)
<
a:
O
o
100 DO -
1000-
100-
10-
0.1 -
D.D1 -
10000-
1000-
~r 100
-p 10
I 2 i y o.!
O.Q1 -
T -r
S 5 1 1
IMP
INDOOR AIR (ng/m3)
IMP
OUTDOOR AIR (ng/m3)
100 00-
^ 1000-
\ :
CD
d 1 00 -
| 10,
I
Z 1 i
Ld i
O '
O 0.1 -
u :
O.D1 -
10000-i
1000-
100-
~r 10-
T T M
1 1 "-I]
0.01 -
5 y
y s
OH HM
OH DC
OH HM
OH DC
Figure 3.5 Indoor and outdoor air concentrations of rram'-permethrin and TCPy measured in
selected studies. Legend: AZ = NHEXAS-AZ, MN = MNCPES, NC HM = CTEPP-NC Home,
NC DC = CTEPP-NC Daycare, OH HM = CTEPP-OH Home, OH DC = CTEPP-OH Daycare,
CHA = CHAMACOS, TEST = Test House.
35
-------
1 10
Chlorpyrifos
100 1000
o o oo
1 10
Diazinon
100 1000
Figure 3.6 Log-scale relationships between levels of parent pesticide (ng/m3) and degradate
(ng/m3) measured in CTEPP. Left Panel: Chlorpyrifos with TCPy. Right Panel: Diazinon with
IMP.
36
-------
3.4 Differences Related to Location
This section addresses differences in potential for exposure related to geographic region,
population density (urban vs. rural), and home vs. daycare environment. There is available
evidence to support all three of these location-related factors as having a discernable impact on
pesticide exposure.
The large observational field studies were conducted in several geographical regions. A
difference in climate impacts the type and density of pests found in the region. Residents of
areas with mild winter conditions, as exist in the southern United States, may experience
significant pest control problems throughout the year and may respond with increased pesticide
usage. The landmark EPA Non-Occupational Pesticide Exposure Study (NOPES) conducted
during 1986-1988 (Whitmore et al, 1994) reported much higher indoor air concentrations of
chlorpyrifos and diazinon in Jacksonville, Florida, than in Springfield and Chicopee,
Massachusetts (purposely selected as high-use and low-use regions, respectively).
The residents of rural communities may be exposed to pesticides from residential as well as
agricultural applications. Both spray drift and work-to-home transport are potential pathways of
exposure to agricultural pesticides, some of which have the same active ingredient as
formulations used within the home (Curl et al., 2002). Residents of urban areas, on the other
hand, may experience frequent applications to combat persistent pest control problems arising
from high population density (Landrigan et al., 1999), may have little control over pesticide
applications by building management, and may be exposed to pesticides applied in neighboring
residences.
Young children spend nearly 20 hours per day indoors (US EPA, 2002). For pre-school age
children, much of this time is spent in residences or in daycare facilities. According to recent
estimates, nearly 4 million children under age 6 spend some portion of their day in center-based
child care, with many children spending a full work day (8-10 hours) in the child care center (US
CPSC, 1999). Pesticide concentrations in daycare facilities are potentially significant (Wilson et
al., 2003) and are typically out of the control of the parents.
Positive and highly significant associations (p < 0.01) between personal-air exposures
and indoor air concentrations were observed in MNCPES for both chlorpyrifos and
diazinon with Spearman correlation coefficients of 0.81 and 0.62, respectively (Table
3.4).
Comparison of the box-and-whisker plots in Figure 3.4 of indoor air concentrations
measured in homes finds median values were somewhat higher in southern states
(NHEXAS-AZ and CTEPP-NC) than in northern states (MNCPES and CTEPP-OH).
However, considerable overlap in the interquartile ranges is evident. Since these studies
focus on compounds that have been used to control a variety of common insect pests both
inside and outside of homes (chlorpyrifos was until recently among the most poplar
residential insecticides for cockroach, flea, ant and termite control), it is not surprising
that the distributions would overlap across geographical locations.
37
-------
When daycare measurements are included, a geographical difference is less obvious
(results not shown). Despite recent gains in the adoption of integrated pest management
policies, many daycare facilities still have regular calendar-based pesticide treatments,
irrespective of actual demonstrated need. This may have the effect of minimizing
differences in usage in daycares among geographic regions.
CTEPP data (Figure 3.7) suggest that, within each state, indoor air levels in daycares are
similar to those in homes, particularly for diazinon and permethrin. This demonstrates
the potential for continued exposure as a child transitions from the home to a daycare. To
reduce the uncertainty of risk assessments for children, their exposures must be
considered for all indoor and outdoor environments they occupy, including homes, child
care centers, and other buildings. Additional information may be required to examine
exposure potential from schools, restaurants, and other public and private locations where
pesticides are also applied.
Differences between urban and rural air concentrations of chlorpyrifos were observed in
both MNCPES (Table 3.5) and CTEPP-OH (Table 3.6). The differences reached
statistical significance only in MNCPES, with higher concentrations in the urban areas.
Likewise, the detection frequencies for both chlorpyrifos and diazinon in indoor and
personal air were higher in urban locations (Table 3.5).
Across compounds in MNCPES, median levels were consistently higher in urban areas
than in rural areas. A reasonable explanation may be that urban areas require more
intensive use of pesticide products to control a range of pests over a wider seasonal span.
In addition the application may be of more mass of active ingredients in a smaller area, as
is the case with a liquid termiticide application. While it is not entirely clear why the
pattern of higher urban levels was not evident in CTEPP-NC, it may be due to a less
stringent definition of "urban" in CTEPP.
Air samples collected in low-income homes generally had higher concentrations of
chlorpyrifos and diazinon than samples collected in medium/high income homes (Table
3.6), but the difference was only statistically significant for diazinon in NC.
38
-------
Table 3.4 Spearman correlations among personal, indoor, and outdoor concentrations of
chlorpyrifos and diazinon measured in MNCPESa.
Type
Personal
Indoor
Chlorpyrifos
Indoor
0.81**
-
Outdoor
0.23
-0.01
Diazinon
Indoor
0.62**
-
Outdoor
0.67**
0.28
a Excerpted from Clayton et al., 2003
** Statistically significant at the 0.01 level.
Table 3.5 Urban and rural differences in airborne concentrations of chlorpyrifos and diazinon
measured in MNCPES. The limit of detection was 0.1 ng/m3.
Sample
Type
Personal
Indoor
Chemical
Chlorpyrifos*
Diazinon*
Chlorpyrifos*
Diazinon
Location
Urban/Suburban
Rural
Urban/Suburban
Rural
Urban/Suburban
Rural
Urban/Suburban
Rural
N
40
20
30
18
57
25
54
21
Detection
Frequency
98%
90%
77%
44%
96%
80%
74%
52%
Median
Concentration
(ng/m3)
2.2
1.2
0.4
0.1
2.2
0.7
0.4
0.1
* denotes significant (p < 0.05) difference in medians using two-sided Wilcoxon test.
Table 3.6 Differences in airborne concentrations measured in CTEPP for urban versus rural, low
versus medium income, and home versus day care expressed as ratios of geometric means.
Adapted from Morgan et al., 2004.
State
North
Carolina
Ohio
Chemical
Chlorpyrifos
Diazinon
Chlorpyrifos
Diazinon
Estimated Ratio of Geometric Means (95% C.I.)
Urban/Rural
0.94
(0.50, 1.77)
0.95
(0.43,2.11)
1.64
(0.80, 3.37)
1.04
(0.44, 2.49)
Low /Mid-High Income
1.36
(0.84, 2.21)
3.59*
(1.95,6.61)
1.63
(0.97, 2.74)
1.67
(0.89,3.12)
Home/Daycare
1.78
(0.81, 3.92)
0.82
(0.30, 2.24)
0.76
(0.38, 1.52)
0.78
(0.34, 1.80)
: denotes significance, p < 0.05.
39
-------
100% i
90%
80%
?
- 70%
C
3 60% -
O"
g 50%
* 40% -
0)
Q
o 30%-
-O
20%
10%
I
I
i
I
pi
>
s
N
N
N
N
N
N
N
S
N
N
N
N
N
N
N
S
N
N
N
N
N
N
N
h
ffS
-------
3.5 Spatial and Temporal Variability
Few studies have been designed to measure either the spatial variability of airborne pesticide
concentrations in a home or the temporal variability following crack-and-crevice pesticide app-
lications (Byrne etal, 1998; Lewis etal, 2001). Recently, the Test House, CPPAES, DIYC,
and PET studies have provided data on both spatial and temporal variability, as shown in Figure
3.8.
Within-home spatial patterns were investigated in the Test House experiments.
Following a crack and crevice application of chlorpyrifos (Figure 3.8 and Table 3.7), the
pesticide was detected in the application room (kitchen), adjacent den, and the farthest
bedroom from the application. Airborne concentrations in the kitchen peaked at 790
ng/m3, then decreased by approximately 80%, but were still measurable, at 21 days after
application. A concentration gradient was observed from the kitchen (application area) to
the den (proximal area) to the master bedroom (distal area).
Between-home spatial variability following a pesticide application was investigated in the
CPPAES and DIYC studies. Indoor air concentrations of chlorpyrifos among the 10
homes in the CPPAES spanned more than an order of magnitude one day after
application (Figure 3.8).
The highest measured chlorpyrifos indoor air concentrations following crack and crevice
applications among a subset of 5 CPPAES homes were between days 0 and 2 post applic-
ation (mean = 315 ng/m3), then decreased throughout the 2-week sampling period (mean
= 172 ng/m3), but were still greater than the pre application levels (mean =18 ng/m3).
The indoor air concentrations for the remaining CPPAES homes were much lower and
did not follow the same decay pattern (data not presented, see Hore et al, 2005).
Air concentrations of diazinon in the homes of the DIYC study were nearly an order of
magnitude higher than concentrations of chlorpyrifos in CPPAES, and the decay pattern
differed dramatically among the three DIYC homes. The difference in airborne diazinon
concentrations among the three homes was most pronounced 4-5 days after application
(Figure 3.8), perhaps partially attributable to both the application method employed and
the amount of active ingredient applied in each home.
Following outdoor granular application to lawns in the PET study, indoor air
concentrations of diazinon generally reached maximal levels by days 1 and 2 post
application and declined over the duration of the study (Figure 3.8).
3.6 Factors that Influence Air Concentrations
Multiple factors influence the concentration of pesticides in air and the potential for inhalation
exposure. The physico-chemical characteristics of the chemicals applied, the formulation type
and the frequency of application are believed to be some of the most important of these factors.
Other factors such as seasonal variation, housing type, pets, occupancy, application location,
type of surface to which the applications are made, and the rooms where the samples are
collected may also influence the concentrations measured. Some of these factors have been
41
-------
investigated using the data from NERL's pesticide exposure measurement program.
The impact of air exchange rate (AER) on air concentrations is shown in Figure 3.8 for
the CPPAES data. Indoor air concentrations of chlorpyrifos (immediately following
application) among the homes spanned more than an order of magnitude. Homes with
low air exchange rates had higher initial airborne concentrations and a noticeably slower
reduction of airborne levels.
The amount, or mass, of active ingredient applied also clearly affected the concentrations
measured in CPPAES, with low airborne concentrations observed in three homes
receiving applications containing only trace amounts of chlorpyrifos (data not presented,
please see Hore et al, 2005).
An empirically derived Application Effective Volume (AEV, applied mass divided by the
product of air changes per hour and home volume) was applied to the CPPAES data to
demonstrate the relationship between measured air concentrations, air exchange rate, and
mass of active ingredient applied. Measured airborne concentration was more
consistently correlated with AEV than with any of the constituents of AEV (Pearson
product-moment correlations, data not presented). The association of AEV with airborne
concentrations measured on the second day after application (Figure 3.9) suggests that
AEV may serve as an effective surrogate for air concentrations and that constituent
measures including air exchange rate are important determinants of air concentrations.
The geometric mean concentrations of the organochlorine, organophosphate, and
pyrethroid pesticides measured in indoor air in the absence of a recent application appear
to be strongly influenced by vapor pressure. Regressing concentrations measured in the
CTEPP study upon the logged vapor pressures (Figure 3.10) results in nearly equivalent
R2 values of 0.69 and 0.70 for homes and daycares, respectively. The importance of
inhalation as a route of exposure for pesticides is likely to decrease as less volatile
pesticides are introduced into the market.
Results in the US EPA Research Test House comparing total release aerosol to crack and
crevice applications confirm that the application method is an important factor
influencing the measured airborne concentration of chlorpyrifos (Table 3.7). The
application method is also suspected of being a factor responsible for the differences
observed among homes in the DIYC study.
The PET study demonstrates the intrusion of diazinon from an outdoor source. The lawn
applications resulted in a source of diazinon that contributed to indoor concentrations in
all homes. Indoor concentrations are likely associated with both the physical
translocation of particle bound residues and the intrusion of volatilized diazinon from the
source. The results suggest that lawn applications increase the potential for occupant
exposure both on the treated lawns and indoors.
While some progress has been made in understanding the multitude of factors that
influence the concentration of pesticides in air and the potential for inhalation exposure,
additional studies are needed.
42
-------
3.7 Summary: Air Concentrations
As shown in the bulleted lists of observations from these studies, there are a number of factors
that may impact children's exposure to pesticides in homes and child care centers. They include
the following:
The physical and chemical characteristics of the pesticides used indoors will have a
significant impact on exposure via the inhalation route. Airborne concentrations will be
higher for the more volatile pesticides, such as chlorpyrifos and diazinon (no longer
registered for indoor use). Use of less volatile alternatives, such as the pyrethroids, will
likely result in lower airborne concentrations of the active ingredients.
The type and method of pesticide application (see Section 2.4) are factors affecting
exposure. As shown in the Test House experiments, the airborne concentrations are
higher for foggers than for crack and crevice applications. Past studies have focused on
crack and crevice and other spray applications, although newer types of applications,
such as use of gels, may further reduce the translocation of pesticides to areas that may be
contacted by children.
The data from these studies highlight the importance of geographic location on airborne
concentrations. Frequency of application and total amount of pesticide used may be
associated with geographic location.
The data on spatial variability of pesticide residues within a home are limited. But, data
from the Test House and other studies show that pesticides are distributed to other
locations within a building from the point of application and are measurable in air
samples collected in other rooms.
The data also clearly show that there are temporal changes in concentrations following an
application. These changes are related to air infiltration and air exchange rates in the
home. The changes are also likely related to degradation processes, but there are few
studies that have addressed the temporal changes in concentration for different pesticides
as related specifically to the degradation process.
43
-------
Table 3.7 Airborne chlorpyrifos residues collected following a crack and crevice type application
versus a total release aerosol in the EPA Test House.
Application
Type
Crack and
Crevice
Total
Release
Aerosol
Room
Kitchen
Den
Bedroom
Living Room
Den
Bedroom
Indoor Air Concentration (ng/m3)
Pre
NCb
3
NC
NDC
ND
NC
3hr
NC
NC
NC
15
17
1.4
Day la
790
250
100
9200
8300
4700
Day 2
NC
NC
NC
4100
4000
NC
Day 3
770
140
0.07
2300
2100
NC
Day 7
320
90
60
860
1100
370
Day 14
220
60
40
450
410
320
Day 21
140
70
30
NC
NC
NC
a Air sampling was initiated immediately following the application and monitored continuously for 24-h.
b NC indicates the sample was not collected.
0 ND indicates the sample was not detected O.05 |j.g/m3
44
-------
900
E 800
1" 700
!ฑ" 600
^ 500
'in 400
O
ฃ 300
g. 200
| 100
ฐ 0
EPA Test House Rooms - Crack and Crevice
*" ^\
\
\
\
\^
*X ""
/. ^--^ .
y \ =
A Kitchen
Den
Bedroom
-
-30369
Days after Application
CPPAESLowand High AER
C
_C
C)
1_
0 mn
o
m\
/\ ,
/ V
-ฑ-
12
15
Homes
--Low AER
-G- High AER
/ \
/ / ~\
L/^\ *-----=*=__=
aซ7 \ ^ =ป -c^-;^^^
^___&_^s*= ซ 0 ~~
*
s=
-30369
Days after Application
_
=
12
I
15
900 -
5- 800 -
1 TOO-
S 600
5 500
.E 400
0 300
c
N 200
ra
b 100
0
PET Study Home
Bed Room
^_
^^''V^ ป
^ ^ -
3 0 3 6 9 12 15
Days after Application
DIYC Study Homes
onnn
D)
C
A Home 1
Home 2
Home 3
f\-*~*^
/ /*\
ฃ/ \
/" m^M
ป ^
~ '*"**-
0 -I 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
-3 0 3 6 9 12 15
Days after Application
Figure 3.8 Airborne concentrations (ng/m3) of chlorpyrifos or diazinon measured from indoor air over time in the Test House, PET,
CPPAES, and DIYC studies.
45
-------
1GGOf
c
o
100:
c
v
u
c
o
10:
1E-6 0.0001 0.01 1
Applied Effective Volume
100
Figure 3.9 Association between measured air concentration (ng/m3) and Applied Effective
Volume (ng/m3/h) on the second day after application of chlorpyrifos in CPPAES homes.
Pesticide Air Cones. In CTEPP Homes vs Vapor Pressure
-1 0
loglOVP(mPa)
1 2
y = 1.77x +3.90
R2 = 0.69
Pesticide Air Cones, in CTEPP Daycares vs Vapor Pressure
y = 1.83x +3.57
R2 = 0.70
Figure 3.10 Pesticide air concentrations as a function of vapor pressure in CTEPP homes (A) and
day cares (B).
46
-------
4.0 SURFACE MEASUREMENTS
4.1 Introduction and Data Availability
The objectives of measuring pesticide surface residue concentrations and loadings are to describe
the extent and distribution of concentrations, identify possible sources of indoor contamination,
evaluate factors that may impact concentrations, and identify elevated concentrations for the
purposes of intervention. Surface measurements tell us what pesticide residues are present in an
environment and at what concentrations. With appropriate transfer coefficients and activity data,
these measurements can be used to estimate dermal and nondietary ingestion exposure.
Although exposure potential is highest during the first few days following an application,
pesticide residues introduced into the indoor residential environment may persist for months or
even years on surfaces or embedded in carpets, where these are protected from sunlight, rain,
temperature extremes, and microbial action (Lewis etal., 1994). Surface residues may
contribute to the exposure of household occupants through multiple routes: dermal absorption,
inhalation of resuspended particles, nondietary ingestion of residues adhering to mouthed objects
and skin, and dietary ingestion resulting from children's unique handling of food (Butte and
Heinzow, 2002). Oral ingestion and dermal absorption of surface residues may be major routes
of exposure for infants and toddlers who spend much of their time on the floor, explore their
world through mouthing, experience frequent hand-to-mouth and object-to-mouth contacts, and
who may have pica tendencies (Butte and Heinzow, 2002; Cohen Hubal et al, 2000a, b;
Freeman et al., 2004; Lewis et al., 1994; Tulve et al., 2002). Ingestion of soil is also a special
concern for young children, who may ingest up to 10 times more soil than adults on a per
kilogram body weight basis (LaGoy, 1987).
Several surface sampling methods exist including deposition coupons, Octadecyl (CIS) surface
press sampler (EL Sampler), Lioy-Weisel-Wainman (LWW) sampler, vacuum, drag bar,
California-roller, PUF roller, and surface wipes. These methods are generally classified by the
degree to which they remove residues from surfaces: total available residue, transferable residue,
and dust (Lewis, 2001). Total available residue methods attempt to measure the total amount of
contaminant on a surface (often with the aid of isopropanol as a solvent), transferable residue
methods are intended to represent the amount that is transferred as a result of contact with the
contaminated surface, and dust collection methods use a vacuum to collect dust-borne residue on
surfaces and from carpet. Transferable residues are also referred to as dislodgeable residues. All
studies discussed in this chapter employed more than one sampling method for surface measure-
ments. Table 4.1 lists the studies that collected surface measurements along with the type of
measurement taken. Limits of detection for each chemical by study and method are listed in
Table 4.2.
Several variables may influence measured dust concentrations or surface loadings of pesticide
residues. These variables include the collection method itself, surface type, compound physico-
chemical characteristics, application method, application frequency, sampling locations,
participant activities, and analytical capabilities. This chapter examines how these factors may
have affected the surface residue measurements in the children's exposure measurement
program, the implications for interpreting the data, and the consequences for exposure estimates.
47
-------
Table 4.1 Studies and sample collection methods for surface measurements.
Study
NHEXAS-AZ
MNCPES
CTEPP
CCC
JAX
CHAMACOS
CPPAES
Test House
PET
DIYC
Daycare
Dust
(ng/g)
/
/
-
/
-
-
/
-
-
Dust Load
(ng/cm2)
/
/
-
/
-
-
-
-
Soil
(ng/g)
/
/
/
-
/
-
-
/
-
-
Total Surface Load
(ng/cm2)
~
LWW
-
Wipes (20 mL IP A)
Wipes (20 mL IP A)
Wipes (20 mL IP A)
Deposition Coupons,
LWW
Deposition Coupons,
Wipes (10 mL IP A)
Wipes (20 mL IP A)
Wipes (20 mL IP A)
Transferable Residues
(ng/cm2)
Wipes (water)
CIS Press
Wipes (2 mL IP A),
PUF Roller
CIS Press
CIS Press
CIS Press
-
PUF Roller
CIS Press
PUF Roller
PUF Roller
PUF Roller,
CIS Press
--, matrix not sampled
LWW, Lioy-Weisel-Wainman sampler
CIS, 3M Empore Octadecyl (CIS) filters
PUF, Polyurethane foam
48
-------
Table 4.2 Limits of detection (ng/g or ng/cm2) for surface measurements by study, method, and
compound.
Study
Method
Chlor-
pyrifos
Diaz-
inon
c-Per-
methrin
t-Per-
methrin
Cyflu-
thrin
Cyper-
methrin
Esfen-
valerate
TCPy
IMP
Soil (ng/g)
MNCPES
CTEPP
CCC
PET
Soil
Soil
Soil
Soil
10
0.5
5
~
10
0.5
2
60
10
0.5
5
~
10
0.5
5
~
~
5
6
-
~
~
6
~
~
~
~
~
~
0.2
~
~
~
0.2
~
~
Dust (ng/cm2 or ng/g)
NHEXAS-AZ
CTEPP
NHEXAS-AZ
CTEPP
CHAMACOS
PET
Dust (ng/cm2)
Dust (ng/cm2)
Dust (ng/g)
Dust (ng/g)
Dust (ng/g)
Dust (ng/g)
0.002
0.0003
4
2
1
~
0.002
0.0003
18
2
1
60
~
0.0003
~
2
1
-
~
0.0003
~
2
1
~
~
0.0030
~
10
100
~
~
~
~
~
~
~
~
~
~
~
~
~
~
0.0003
~
2
~
~
~
~
~
2
~
~
Total Available Residue (ng/cm2)
NHEXAS-AZ
MNCPES
CCC
JAX
CHAMACOS
CPPAES
CPPAES
CPPAES
TESTHOUSE
TESTHOUSE
DIYC
DAYCARE
IPA Wipe
LWW
IPA Wipe
IPA Wipe
IPA Wipe
IPA Wipe
LWW
Dep Coup
IPA Wipe
Dep Coup
IPA Wipe
IPA Wipe
0.070
1.200
0.005
0.005
0.005
0.001
0.030
0.010
0.001
0.010
~
~
2.00
3.50
0.002
0.002
0.005
~
~
~
~
~
0.300
~
~
~
0.005
0.005
0.005
~
~
~
~
~
~
~
~
~
0.005
0.005
0.002
~
~
~
~
~
~
~
~
~
0.006
0.006
~
~
~
~
~
~
~
~
~
~
0.006
0.006
~
~
~
-
~
-
~
~
~
~
~
0.008
~
~
~
~
~
~
~
0.400
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
Transferable Residue (ng/cm2)
MNCPES
CTEPP
CTEPP
TESTHOUSE
TESTHOUSE
PET
DIYC
CIS Press
IPA Wipe
PUF
CIS Press
PUF
PUF
CIS Press
0.330
0.0007
0.0004
0.030
0.001
~
~
0.140
0.0007
0.0004
~
~
0.030
1.200
~
0.0007
0.0004
~
~
~
~
~
0.0007
0.0004
~
~
~
~
~
0.007
0.004
~
~
~
~
-
~
~
~
~
~
~
~
~
~
~
~
~
~
~
0.0007
0.0004
~
~
~
~
~
0.0007
0.0004
~
~
~
~
, analyte not measured
49
-------
4.2 Dust and Soil Measurements
Dust is considered a repository of environmental pollutants that have accumulated indoors from
both internal and external sources. Dust collected by vacuum is usually sieved to retain a
particular size fraction for analysis, which may have important implications since pesticide
concentrations are inversely related to particle size (Lewis etal, 1999). Measurements in dust
may be reported as concentrations (mass residue per unit weight of dust, ng/g) or as loadings
(mass residue per unit area sampled, ng/cm2). There is a lack of consensus on which of these
metrics is more relevant to human exposure to pesticides; however, lead studies have suggested
that lead loading correlates better with children's blood lead levels than does lead concentration
(Lanphear, 1995).
Pesticides were measured in dust samples from the NHEXAS-AZ, CTEPP, CHAMACOS and
PET studies. The CTEPP, CHAMACOS, and PET studies used the High Volume Small Surface
Sampler (HVS3), whereas NHEXAS-AZ used a modified commercially available vacuum for
ease of sample collection. The HVS3 was developed for the EPA and efficiently collects carpet-
embedded dust retaining the associated pesticides (Roberts et al, 1991; Lewis et al, 1994). The
HVS3 is a high-powered vacuum cleaner equipped with a nozzle that can be adjusted to a
specific static pressure and air flow rate. A cyclone removes particles >5 urn from the air stream
for collection in a catch bottle. Use of this sampler is limited to floors or other large flat surfaces
(Roberts etal, 1991; Ness, 1994; Lewis et al, 1994). The ASTM (American Society for Testing
and Materials) method for the collection of carpet-embedded dust requires an apparatus with the
specifications of the HVS3 (ASTM, 1993). Pesticide concentrations in soil were measured in the
same studies and results have been included in this chapter to allow comparisons between indoor
and outdoor exposure pathways for the same children.
Pesticide Presence in Dust and Soil
Detection limits are listed in Table 4.2. Detection frequencies are presented in Figure 4.1 for soil
samples and Figure 4.2 for dust samples. Concentrations of pesticides in soil and dust samples at
the median and 95th percentile are listed in Table 4.3 (complete summary statistics are listed in
Tables A.8 through A. 19 in Appendix A).
With the exception of cyfluthrin (for which analytical difficulties produced a higher
detection limit), dust samples had high detection frequencies (>95%) in CTEPP and
CHAMACOS. Detection frequencies were lower in NHEXAS-AZ due to higher
detection limits.
The high detection frequencies of pesticides observed in dust across studies is consistent
with dust being a repository of contaminants.
Detection frequencies for soil samples, on the other hand, were generally low (Figure
4.1). The high detection frequency of diazinon in PET study soil was due to direct lawn
applications of the pesticide prior to sample collection.
Pesticide concentrations were much lower in soil samples than in dust samples. In
general, soil levels at the 95th percentile were a factor of 10 to 100 times lower than dust
levels at the same percentile. This result suggests that in the absence of outdoor turf
treatments, ingestion of soil may not be an important exposure pathway for these
50
-------
pesticides, with the possible exception of children exhibiting pica behavior.
Concentrations in Dust and Soil: Summary Findings
Lognormal probability plots that graphically depict pesticide concentrations in soil from large
observational field studies are presented in Figure 4.3. Plots that depict pesticide concentrations
and loadings in dust are given in Figures 4.4 and 4.5. Box-and-whisker plots comparing
pesticide concentrations and loadings in dust across all studies are given in Figures 4.6 and 4.7.
The upper tails of the soil concentration distributions tend to be in the same range as the
lower tails of the dust concentration distributions (Figures 4.3-4.5). For example, the 95th
percentile for both chlorpyrifos and diazinon in soil is approximately 10 ng/g, and the 5th
percentile for both of these compounds in dust is also near 10 ng/g.
Among the pesticides measured in soil, cyfluthrin stands out for its high values at the
95th percentile (Table 4.3). Due to the low detection frequencies, no additional analysis
was conducted with the soil data.
Comparisons of concentrations in dust across studies (Figures 4.4-4.5) show permethrin
(a pyrethroid) to be about an order of magnitude higher than chlorpyrifos and diazinon
(both organophosphates).
Overall, diazinon concentrations are lower than all other pesticides reported in dust, as
illustrated in the box-and-whisker plots (Figures 4.6-4.7).
High loadings of diazinon in indoor house dust following the lawn treatment in the PET
study suggest translocation into the house by the occupants and their pets.
The concentration ranking among the compounds in dust is the opposite of that found in
air where the more volatile pesticides showed the higher concentrations. The less volatile
pyrethroid pesticides tend to partition to the dust and may degrade more slowly, allowing
accumulation over time from repeated applications. These results point to the importance
of dust as a primary residential exposure medium for the less volatile pesticides. In
addition, the exposure factors that are important for other nonvolatile contaminants such
as lead (Melnyk et a/., 2000) may also be important for the less volatile pesticides.
In general, the lognormal plots (Figures 4.4-4.5) indicate that differences between study
populations are more apparent with dust loadings than with dust concentrations.
In CTEPP, pesticide loadings in surface dust (ng/cm2) were higher in daycare centers
(DC) than in homes (HM) (Figures 4.6-4.7). This appears to be a function of the amount
of surface dust present, as the pesticide concentrations in the dust do not differ by much
(Figures 4.6-4.7). Studies with lead have suggested that loading has a greater impact than
concentration on intake, and the same may or may not be true for pesticides.
Concentrations of chlorpyrifos in dust (ng/g) are similar across studies (Figure 4.4)
suggesting that the usage of chlorpyrifos did not change significantly from the timeframe
of the NHEXAS-AZ study (1995-1997) to the CTEPP study (2000-2001).
As with the other surface measurement methods, cis- and ^raw^-permethrin have similar
concentration profiles in dust samples.
51
-------
cth
Table 4.3 Median and 95 percentile values for soil (ng/g) and dust (ng/cm2 and ng/g) measurements by study.
Units
Chlorpyrifos
P50
P95
Diazinon
P50
P95
c-Permethrin
P50
P95
/-Permethrin
P50
P95
Cyfluthrin
P50
P95
TCPy
P50
P95
IMP
P50
P95
SOIL
MNCPES
CTEPP-NC If
CTEPP-NC d
CTEPP-OH h
CTEPP-OH d
CCC
PET
ng/g
ng/g
ng/g
ng/g
ng/g
ng/g
ng/g
<10.0
<0.5
<0.5
<0.5
<0.5
<5.0
~
<10.0
17.0
0.8
14.0
6.2
27.0
~
<10.0
<0.5
0.5
O.5
O.5
<2.0
22000
<10.0
4.2
0.5
4.7
7.1
22.0
50000
~
O.5
0.5
O.5
O.5
<5.0
~
~
13.0
2.6
2.7
O.5
8.6
~
~
O.5
0.5
O.5
O.5
<5.0
~
~
18.0
2.2
2.1
O.5
12
~
~
<5.0
<5.0
<5.0
<5.0
<6.0
~
~
32.0
42.0
64.0
42.0
8.6
~
~
0.6
0.2
0.7
0.6
-
~
~
11.0
1.2
8.9
6.3
~
~
~
~
~
O.2
O.2
~
~
~
~
~
2.1
1.4
~
~
DUST (Loadings)
NHEXAS-AZ
CTEPP-NC h
CTEPP-NC d
CTEPP-OH h
CTEPP-OH d
PET
ng/cm2
ng/cm2
ng/cm2
ng/cm2
ng/cm2
ng/cm2
0.007
0.009
0.066
0.006
0.046
~
2.80
0.42
1.30
0.35
0.89
~
0.002
0.002
0.026
0.002
0.022
0.350
0.18
0.12
9.90
0.31
0.39
68
~
0.10
0.69
0.05
0.27
~
~
4.90
5.50
3.80
4.80
~
~
0.09
0.41
0.03
0.31
~
~
4.40
6.30
3.90
4.70
~
~
O.003
O.003
0.018
0.140
~
~
0.16
0.60
0.25
1.10
~
~
0.008
0.020
0.004
0.024
~
~
0.37
0.37
0.16
0.40
~
~
~
~
0.001
0.004
~
~
~
~
0.046
0.072
~
DUST (Concentrations)
NHEXAS-AZ
CTEPP-NC h
CTEPP-NC d
CTEPP-OH h
CTEPP-OH d
CHAMACOS
PET
ng/g
ng/g
ng/g
ng/g
ng/g
ng/g
ng/g
140
130
140
52
180
49
~
120000
1200
920
1400
1100
1200
~
150
18
47
20
38
21
3100
8000
390
6900
1700
1600
820
150000
~
800
890
470
690
150
~
~
21000
10400
7600
3800
2900
~
~
630
760
340
480
40
~
~
19000
12000
9200
3400
15000
~
~
47
79
200
350
<50
~
~
1700
1500
1300
890
303.6
~
~
96
63
41
67
~
~
~
1100
300
820
500
~
~
~
~
~
14
17
~
~
~
~
~
310
~
~
a CTEPP: h = home, d = daycare
--, analyte not measured
52
-------
Detection Frequency: Soil
100-
90-
80-
ฃ 70-
o
S 60-
3
S. 50-
| 40-
t! 30-
Q
20-
10-
n-
IF
-
rm
i-i
-
-
-
r
In HI in n
Chlorpyrifos TCPy Diazinon IMP c-Perm t-Perm Cyfluthrin Cypermeth
^CTEPP-NC IZZICTEPP-OH IZZICCC I 1 PET
Figure 4.1 Detection frequencies of pesticides and degradates in soil.
Detection Frequency: Dust
100-
90-
80-
ฃ 70-
u
S 60-
O"
S. 50-
L|_
C
o 4Q.
1
ง 3ฐ-
20-
10-
|
|
|
|
I
1
1
1
H
M
M
-
I
|
|
|
|
I
1
1
1
H
H
n
-
-
1
1
1
1
I
1
1
1
n
n
M
-
I
III
Hi
Hi
Hi
ii
ii
ii
-
-
-
Chlorpyrifos TCPy Diazinon IMP c-Perm t-Perm Cyfluthrin
^CTEPP-NCCZICTEPP-OH CZICHAMACOS l~~1PET
Figure 4.2 Detection frequencies of pesticides and degradates in dust.
53
-------
CHLORPYRIFOS
SOIL CONCENTRATION (ng/g)
DIAZINON
SOIL CONCENTRATION (ng/g)
1 00000 -
10000 -
1000
100 -
10 -
1 -
>
9
ฃ
^
ฐT
if A
e
*
O
*o
X
1.2.51 2 5 10 2030 50 7080 9095 99 99
1 00000 ]
1000D 1
1000 1
100 -
ID I
1 ]
.1 -
9
J
*%
G*
.
*
O
S&SKX
fT
1.2.51 2 5 10 2030 50 7080 9095 99 99.
Percent Percent
XXX MNCPES * * * CTEPP-NC HOME XXX MNCPES * * * CTEPP-NC HOME
ODD CTEPP-NC DAYCARE O O O CTEPP-OH HOME D O D CTEPP-NC DAYCARE O ซ O CTEPP-OH HOME
A A A CTEPP-OH DAYCARE CCC A A A CTEPP-OH DAYCARE CCC
1 00000 '
10000 '
1000 -
100 -
10 -
1 '
CIS-PERM ETHRIN
SOIL CONCENTRATION (ng/g)
/*
*
oo?0
"
1.2.51 2 5 10 2030 50 7080 9095 99 99
1 00000 1
10000 ]
100D 1
100 1
10 -
1 -
.1 -
9
TRANS-PERM ETHRIN
SOIL CONCENTRATION (ng/g)
f*
*
ffig^S
1.2.51 2 5 10 2030 50 7080 9095 99 99.
Percent Percent
* * * CTEPP-NC HOME ODD CTEPP-NC DAYCARE * * * CTEPP-NC HOME ODD CTEPP-NC DAYCARE
O O O CTEPP-OH HOME A A A CTEPP-OH DAYCARE O O O CTEPP-OH HOME A A A CTEPP-OH DAYCARE
CCC CCC
1 00000
1 0000 -
1000 -
100
10 -
1 -
.1
CYFLUTHRIN
SOIL CONCENTRATION (ng/g)
'
^fiS*
^
1 0000 D 1
10000 1
1000 1
100 l
10 1
1 -
.1 -
TCPY
SOIL CONCENTRATION (ng/g)
*
,
*
ฃ
L^
P""~ A
,
**
0*
,
.1.2.51 2 5 10 2030 50 7080 9095 99 99.9
Percent
* * * CTEPP-NC HOME
000 CTEPP-OH HOME
CCC
D D D CTEPP-NC DAYCARE
A A A CTEPP-OH DAYCARE
.1.2.51 2 5 1D 2030 50 708D 9095 99 99.9
Percent
* * * CTEPP-NC HOME
000 CTEPP-OH HOME
n n n CTEPP-NC DAYCARE
A A A CTEPP-OH DAYCARE
Figure 4.3 Lognormal probability plots of soil concentrations (ng/g) for chlorpyrifos, diazinon,
c/5-permethrin, fr'am'-permethrin, cyfluthrin, and TCPy.
54
-------
CHLORPYRIFOS
DUST CONCENTRATION (ng/g)
CHLORPYRIFOS
DUST LOADING (ng/cm2)
.512 5 10 2030 50 7080 9095
Percent
ODD
A A A
NHEXAS-AZ
CTEPP-NC DAYCARE
CTEPP-OH DAYCARE
* * * CTEPP-NC HOME
000 CTEPP-OH HOME
.1.2.51 2 5 10 20304-0 607080 9095 99
Percent
+ + + NHEXAS-AZ
D O D CTEPP-NC DAYCARE
A A A CTEPP-OH DAYCARE
* * * CTEPP-NC HOME
O ซ O CTEPP-OH HOME
DIAZINON
DUST CONCENTRATION (ng/g)
DIAZINON
DUST LOADING (ng/cm2)
.51 2 5 10 2030 50 7080 9095
Percent
+ + -+
ODD
A A A
NHEXAS-AZ
CTEPP-NC DAYCARE
CTEPP-OH DAYCARE
* * * CTEPP-NC HOME
O O O CTEPP-OH HOME
.1.2.51 2 5 10 203D4-0 6D70 80 9095 99
Percent
+ + + NHEXAS-AZ
D O D CTEPP-NC DAYCARE
A A A CTEPP-OH DAYCARE
* * CTEPP-NC HOME
O O CTEPP-OH HOME
CIS-PERM ETHRIN
DUST CONCENTRATION (ng/g)
CIS-PERMETHRIN
DUST LOADING (ng/cmZ)
.1 .51 2 5 10 2030 50 7080 9095 99 99.9
Percent
.1.2.51 2 5 10 203D40 607080 9095 99 99.9
Percent
* * * CTEPP-NC HOME
O O ซ CTEPP-OH HOME
D D D CTEPP-NC DAYCARE
A A A CTEPP-OH DAYCARE
* * * CTEPP-NC HOME
O O O CTEPP-OH HOME
n n n CTEPP-NC DAYCARE
A A A CTEPP-OH DAYCARE
Figure 4.4 Lognormal probability plots of dust concentrations (ng/g) and loadings (ng/cm2) for
chlorpyrifos, diazinon, and c/'s-permethrin.
55
-------
TRANS-PERMETHRIN
DUST CONCENTRATION (ng/g)
TRANS-PERMETHRIN
DUST LOADING (ng/cm2)
.512 5 10 2030 50 70BO 9095
Percent
* * *
o o o
CTEPP-NC HOME
CTEPP-OH HOME
D D O CTEPP-NC DAYCARE
A A A CTEPP-OH DAYCARE
.1.2 .5 1 2 5 10 203040 607080 9095 99
Percent
* * * CTEPP-NC HOME
000 CTEPP-OH HOME
D D D CTEPP-NC DAYCARE
A A A CTEPP-OH DAYCARE
CYFLUTHRIN
DUST CONCENTRATION (ng/g)
CYFLUTHRIN
DUST LOADING (ng/cm2)
1 000000 1
100000 1
10000 1
1000 1
100 1
10 ]
1 ]
.1 -
<
A*
X
i
*
y&
7
n
sk
&*
H*Sซ*
r
1 .51 2 5 10 2030 50 7080 9095 99 99.
Percent
* * * CTEPP-NC HOME D D O CTEPP-NC DAYCARE
000 CTEPP-OH HOME A A A CTEPP-OH DAYCARE
.00001 \
.1.2 .5 1 2
5 10 203040 6070 SO 90 95 99
Percent
* * * CTEPP-NC HOME
O O O CTEPP-OH HOME
nan CTEPP-NC DAYCARE
A A A CTEPP-OH DAYCARE
TCPY
DUST CONCENTRATION (ng/g)
TCPY
DUST LOADING Cng/cmZ)
.512 5 10 2030 50 7DBO 9095
Percent
.1.2 .5 1 2 5 10 203040 6D70 80 9095 99
Percent
CTEPP-NC HOME
CTEPP-OH HOME
n n n CTEPP-NC DAYCARE
A A A CTEPP-OH DAYCARE
* * * CTEPP-NC HOME
000 CTEPP-OH HOME
n n n CTEPP-NC DAYCARE
A A A CTEPP-OH DAYCARE
Figure 4.5 Lognormal probability plots of dust concentrations (ng/g) and loadings (ng/cm2) for
tmns-permethrin, cyfluthrin, and TCPy.
56
-------
CHLORPYRIFOS
DUST CONCENTRATION (ng/g)
CHLORPYRIFOS
DUST LOADING (ng/cm2)
o
ฃ
UJ
o
o
o
10DOODO -i
100000
10000
1000
100
10
1
0.1 -
(N
E
o
en
c
u
z
Q
0.1
0.01
0.001
0.0001
0.00001 -
I
I I I I I I
AZ NC HM NC DC OH HM OH DC CHA
AZ
I I I I I
NC HM NC DC OH HM OH DC CHA
DIAZINON
DUST CONCENTRATION (ng/g)
DIAZINON
DUST LOADING (ng/cm2)
1 0DOODO i
^ 100000-
c 10000-
O 1000-
ฃ
0; 100-
UJ
0 10-
o
0 1 -
0.1 -
I
1
_
-, F
3
_
q r
L _
i n i
F I 2
_
100 i
o
"
0.1
0.01
0.001
0.0001
n i i i i r
K NC HM NC DC OH HM OH DC CHA PET
\ I I I I I I
AZ NC HM NC DC OH HM OH DC CHA PET
CIS-PERMETHRIN
DUST CONCENTRATION (ng/g)
CIS-PERMETHRIN
DUST LOADING (ng/cm2)
Dl
O
~
.
o
u
1000000
100000-
10000
1000
100
10
1
0.1 -
E
o
en
t;
u
z
Q
100
10-
1
0.1
0.01
0.001
0.0001
0.00001 -
I I I I I
NCHM NCDC OHHM OH DC CHA
I I I I I
NC HM NC DC OH HM OH DC CHA
Figure 4.6 Box-and-whisker plots of dust concentrations (ng/g) and loadings (ng/cm2) for
chlorpyrifos, diazinon, and c/'s-permethrin.
57
-------
TRANS-PERMETHRIN
DUST CONCENTRATION (ng/g)
TRANS-PERMETHRIN
DUST LOADING (ng/cm2)
O>
C
O
o
o
10DOODO
100000
10000
1000
100
10
1
0.1 -
(N
E
o
en
c
u
z
Q
0.1
0.01
0.001
0.0001
0.00001 -
I I I I I
NC HM NC DC OH HM OH DC CHA
I I I I I
NC HM NC DC OH HM OH DC CHA
CYFLUTHRIN
DUST CONCENTRATION (ng/g)
CYFLUTHRIN
DUST LOADING (ng/cm2)
o
UJ
0
o
o
10DOODO
100000
10000-
1000
100
10
1
0.1 -
I
I I I I I
NC HM NC DC OH HM OH DC CHA
100 1
10-
r~-^ '
CM
E 1 1
O :
> ฐ-1l
o 0.01 -
Q :
o ฐ-Da1 i
_1 :
0.0001 -
0.00001 -
T fi T f
^jQi
I I I I I
NC HM NC DC OH HM OH DC CHA
TCPY
DUST CONCENTRATION (ng/g)
TCPY
DUST LOADING (ng/cm2)
z
o
Ld
O
z
o
u
1000000
100000 i
10000
1000^
100
10-
0.1 -
I I I
NC m NC DC OH HM
(N
E
o
en
t;
U
z
Q
100-
10
1
0.1
0.01
0.001
0.0001 i
0.00001 -
OH DC
NCHM
NCDC
OHHM
OH DC
Figure 4.7 Box-and-whisker plots of dust concentrations (ng/g) and loadings (ng/cm2) for trans-
permethrin, cyfluthrin, and TCPy.
58
-------
4.3 Total Available Residue Measurements
Total available residue methods are intended to measure the total amount of contaminant on a
surface. These methods involve either a solvent-assisted mechanical (wiping) action or the
stationary capture of descending airborne droplets and particles. Total available residue loadings
were measured in:
NHEXAS-AZ using the LWW sampler,
MNCPES using the LWW sampler,
CCC from the floors and other surfaces (e.g., counters, desktops) using surface wipes,
JAX from the floor in the application area using surface wipes,
CHAMOCOS using surface wipes,
CPPAES using the LWW and deposition coupons,
Test House using deposition coupons and surface wipes,
DIYC using surface wipes, and
Day care using surface wipes.
The Lioy-Weisel-Wainman (LWW) sampler (Patent #RWJ-91-28) was developed to
quantitatively measure dust on smooth surfaces and has been validated in laboratory and field
tests (Lioy et al, 1993; Freeman et al, 1996). The LWW sampler achieves quantitative wipe
collection using a movable constant pressure block within a template marking a specific area of
100 cm2. Octadecyl-bonded (CIS) disks that have been immersed in isopropyl alcohol are
attached to a silicon rubber pad on the block. More details about this sampler can be found in
Gurunathan et al. (1998) and Hore (2003).
Surface wipes are typically surgical dressing sponges wetted with isopropyl alcohol (IPA). The
sponge is wiped multi-directionally through a defined area in an S-shaped configuration. Floor
locations where young children may spend the most amount of time are usually selected.
Residue loadings on irregularly shaped objects such as toys that are frequently handled by
children (for estimating indirect ingestion exposures) are also measured using the wipe method.
Deposition coupons are used to estimate surface loadings of airborne and dust-bound residues
that "settle out" of the air following an application (Ness, 1994). These consist of a sorptive
material (e.g., cotton, sponge, rayon) with a non-sorptive backing (aluminum foil) (Stout and
Mason, 2003) and are placed in locations where the coupons will not be disturbed. Coupons may
be repeatedly collected and replaced (interval) or collected only at the end of the sampling event
(cumulative). Both interval and cumulative types were collected in CPPAES, whereas only
interval deposition coupons were used in the Test House.
59
-------
Pesticide Presence in Total Available Residues
Limits of detection for each chemical by study are given above in Table 4.2. Detection
frequencies are given in Figure 4.8.
The limits of detection varied widely among studies, but are similar within a study for
both organophosphate and pyrethroid pesticides.
Following dust methods, total available residue methods have the lowest limits for
detection.
Detection frequencies were slightly higher for the organophosphate pesticides in two of
the three studies where both OP and pyrethroid pesticides were measured.
Detection frequencies were higher in the smaller, focused studies than in the survey
studies due to timing of the measurements with respect to recent applications.
Total Available Residues: Summary Findings
Surface loadings for the median and 95th percentile are listed in Table 4.4 for all of the pesticides
that were detected across studies (complete summary statistics are listed in Tables A.20 through
A.24 in Appendix A). Lognormal probability plots are presented in Figure 4.9 for the most
frequently detected pesticides which include chlorpyrifos, diazinon, cis- and ^ram'-permethrin,
cyfluthrin, and cypermethrin. The MNCPES data are not included because of the comparatively
high detection limit and low detection frequencies. Box and whisker plots that graphically depict
the total available residue loading results from all studies are given in Figure 4.10.
In wipe samples, permethrin levels reported at the 95th percentile were approximately an
order of magnitude higher than chlorpyrifos and diazinon levels at the 95 percentile
(Table 4.4).
Levels of diazinon and esfenvalerate reported at the 95th percentile were at least an order
of magnitude higher in studies with a known application (DIYC, Day care) than in the
survey studies (CCC, JAX-Screening).
The lognormal probability plots (Figure 4.9) show that loadings of all frequently detected
pesticides are substantially higher in the JAX screening wipe samples than in the CCC
and CHAMACOS wipe samples.
The total available residue distributions (Figure 4.9) of chlorpyrifos and cis- and trans-
permethrin are relatively similar to each other within a specific large observational field
study.
Cypermethrin loadings tend to be the highest and diazinon loadings tend to be the lowest
(Figure 4.9) of the pesticides of interest in the large observational field studies.
The boxplots (Figure 4.10) reveal that chlorpyrifos, diazinon, and esfenvalerate loadings
are substantially higher in those studies with a known application (CPPAES, Test House,
DIYC, and Daycare).
60
-------
Low cyfluthrin loadings in wipe samples in Figure 4.9 (substantially lower than all other
pesticide residues) suggest that cyfluthrin may not have been routinely used for pest
treatment.
MNCPES and CPPAES are the only studies that employed the LWW. The chlorpyrifos
loadings measured in CPPAES were significantly higher (ANOVA, p=0.002, test results
not presented) due to known pesticide applications coinciding with the sampling period.
Although the MNCPES measurements did not coincide with a pesticide application, 62%
of the LWW samples had detectable levels of chlorpyrifos, suggesting that chlorpyrifos
remains on residential surfaces for a long period of time. It is unclear, however, how
much of this is readily available for transfer and how much is freed from the pores and/or
body material of the surfaces by the mechanical and solvent action of the LWW sampler.
Mean post-application deposition coupon levels were significantly higher in the Test
House than in CPPAES (ANOVA, pO.OOOl, test results not presented). Factors
responsible may include the following: three CPPAES homes received applications with
only trace chlorpyrifos concentrations; the application performed in the Test House may
have been more thorough than applications in the CPPAES homes; the Test House may
have had a higher application of active ingredient per effective volume of the home (see
Section 3.6), and some of the CPPAES occupants reported cleaning their homes and/or
intentionally increasing ventilation after application, thereby reducing the amount of
chlorpyrifos available for movement and capture on a deposition coupon.
In studies (e.g., CPPAES) where surface wipe samples were collected both pre- and post-
application of a semi-volatile pesticide such as chlorpyrifos, the post-application
pesticide loadings were higher than the pre-application values, including on surfaces that
did not receive a direct application. This suggests that semi-volatile pesticides rapidly
translocate from application surfaces to adjacent surfaces. We do not yet have
information on the speed or extent of translocation for less volatile pesticides like
pyrethroids.
Two types of locations were sampled in JAX, the application area and a play area. In
general, the surface residue loadings were higher at the application area than at the play
area.
The surface wipe samples collected in the CCC study were collected from two locations
in each of the randomly selected rooms of the child care centers: a floor and desk
top/table top surface. In general, the floor residue loadings were higher.
61
-------
Detection Frequency: Total Surface Loading
IUU
90-
80-
2. 70-
o
g 60-
3
C
~ 40-
'S
01
la 30-
Q
20-
10-
|
3
|
i
i
g
JP
Chlorpyrifos Diazinon c-Perm t-Perm Cyfluthrin Cypermeth Esfenval
NHEXAS-AZIPA ^ffl MNCPES LWW t=l r.r.r. iPfl mTTIJAX-SCR IPA
IPA ^^CPPAES IPA K5S CPPAES LWW [ZZZCPPAESDC
IPA CLLDTESTHOUSE DC KX3DIYCIPA EI3 DAYCARE IPA
Figure 4.8 Detection frequencies for pesticides using total available residue collection methods.
62
-------
cth
Table 4.4 Median and 95 percentile values for total available residues (ng/cm2) by study.
Study
NHEXAS-AZ
MNCPES
ccc
JAX-SCR
JAX-AGG
CHAMACOS
CPPAES Pre
CPPAES
CPPAES
CPPAES
TESTHOUSE Pre
TESTHOUSE
TESTHOUSE
DIYC Pre
DIYC
DAYCARE
Method
IPA Wipe
LWW
IPA Wipe
IPA Wipe
IPA Wipe
IPA Wipe
LWW
LWW
IPA Wipe
Dep Coup
IPA Wipe
IPA Wipe
Dep Coup
IPA Wipe
IPA Wipe
IPA Wipe
Chlorpyrifos
P50
0.07
1.20
0.03
0.53
0.10
0.05
0.17
0.61
0.03
1.40
4.70
11.00
3.20
~
-
-
P95
7.5
1.5
0.9
10.0
3.1
0.2
1.3
10.0
0.2
9.6
9.1
36.0
62.0
~
-
-
Diazinon
P50
<2.000
<3.500
0.002
0.110
O.002
0.040
-
~
-
-
~
-
-
3.8
5.5
-
P95
<2.0
3.5
0.5
3.3
4.0
0.1
-
~
-
-
~
-
-
21.0
72.0
-
c-Permethrin
P50
-
~
0.009
2.200
0.210
0.100
-
~
-
-
~
-
-
~
-
-
P95
-
~
0.67
32.00
42.00
1.70
-
~
-
-
~
-
-
~
-
-
/-Permethrin
P50
-
~
0.02
2.90
0.26
0.20
-
~
-
-
~
-
-
~
-
-
P95
-
~
1.1
40.0
67.0
3.6
-
~
-
-
~
-
-
~
-
-
Cyfluthrin
P50
-
~
O.006
0.006
O.006
O.050
-
~
-
-
~
-
-
~
-
-
P95
-
~
0.08
4.30
10.00
0.40
-
~
-
-
~
-
-
~
-
-
Cypermethrin
P50
-
~
O.006
2.600
~
-
-
~
-
-
~
-
-
~
-
-
P95
-
~
0.8
750.0
~
-
-
~
-
-
~
-
-
~
-
-
Esfenvalerate
P50
-
~
0.008
~
-
-
~
-
-
~
-
-
~
-
3.200
P95
-
~
3.5
~
-
-
~
-
-
~
-
-
~
-
51.0
--, pesticide not measured
63
-------
CHLORPYRIFOS
TOTAL SURFACE LOADING (ng/cmZ)
DIAZINON
TOTAL SURFACE LOADING (ng/cm2)
10000 -
1000 -
100 '
10 '
1 -
.1 -
.01 -
.001
1
*
^ปM
j*"*"
P^
^
^
*r
'
^0***
f**^
^rf?
lฃ$' '
* #
^Fo
1 .2 .5 1 2 5 10 20304050607080 9095 99 99
10000 1
1000 1
100 1
10 1
1 i
.1 i
.01 1
.001
9
X x *?*&?*
Jr^
Jg*>*l4^r'
i i
*
ff8""
a
>
,
1.2 .5 1 2 5 10 20304050607080 9095 99 99.
Percent Percent
+ + -+ NHEXAS-AZ SILL WIPE CCC FLOOR WIPE + + + NHEXAS-AZ SILL WIPE XXX MNCPES LWW
O O O CCC PLAY AREA WIPE * * # JAX-SCR WIPE ) CCC FLOOR WIPE O O O CCC PLAY AREA WIPE
* * * CHAMACOS WIPE # # # JAX-SCR WIPE A * * CHAMACOS WIPE
10000 -
1000 '
100 -
10
1 -
.1
.01 -
.001 -
CIS-PERMETHRIN
TOTAL SURFACE LOADING (ng/cm2)
*
^*
*
ft
>
****
/
**
jjr
*
sฃ
^***
*#ป
^A
vf
r
ป*0
g**""
1 .2 .5 1 2 5 10 20304050607080 90 95 99 99
10000 1
1000 1
100 1
10 I
1 -
.1 1
.01 1
.001 -
9
TRANS-PERMETHRIN
TOTAL SURFACE LOADING (ng/cm2)
-
4
/
&*
/
^
w
.
**%
r
F^
*J^
^Btair
*
* 0
*
1.2 .5 1 2 5 10 203040506070 BO 90 95 99 99.
Percent Percent
CCC FLOOR WIPE O O O CCC PLAY AREA WIPE CCC FLOOR WIPE O O O CCC PLAY AREA WIPE
* * * JAX-SCR WIPE ft ft * CHAMACOS WIPE * * * JAX-SCR WIPE ft ft * CHAMACOS WIPE
10000 '
1000 -
100 '
10 '
1 -
.1 '
.01 -
.001 '
CYFLUTHRIN
TOTAL SURFACE LOADING (ng/cm2)
i
i
i
i
i
i
i
i
i
i
i *
^f**Lx*
i
i
i
* I a
1
1
i
1 .2 .5 1 2 5 10 20304050607080 9095 99 99
10000 1
1000 1
100 1
10 1
1 i
.1 i
.01 ]
.001 '
9
CYPERMETHRIN
TOTAL SURFACE LOADING (ng/cm2)
:
-------
CHLORPYRIFOS
TOTAL SURFACE LOADING (ng/cm2)
DIAZINON
TOTAL SURFACE LOADING (ng/cm2)
10000-;
1000-!
csT 100-.
E !
\ 10n
-5 i.;
C5 :
1 Ml
O D.01 n
0.001 -,
0.0001 -
__^
E
]
J
10000-j
1000-j
~ ~r iooi
~T Pn
n ^ ^ ^ y " ij
- h 1 1 o^
0.001 -i
0.0001 -
-T
B
IT i
GiiD?
JAX-SC JAX-AG
CIS-PERMETHRIN
TOTAL SURFACE LOADING (ng/cm2)
TRANS-PERMETHRIN
TOTAL SURFACE LOADING (ng/cm2)
10000-!
1000-
C? 100-
E
\ 10-
^
O
0.1 -
Q
O D.D1 -
0.001 -
0.0001 -
r
[
lOOOOi
1000-
100-
n T
1 -
I I I
1 1 Q J
"1 \~^
-J 0.01 -
~ 0.001 -
0.0001 -
r
I
_
S I T
I I-*"!
1 LT '
I 1 I
n^
CHA
CYPERMETHRIN
TOTAL SURFACE LOADING (ng/cm2)
ESFENVALERATE
TOTAL SURFACE LOADING (ng/cm2)
E
en
^c_
Q
0
10000-,
1000-j
IDO-i
1-
0.1 ;
0.01 !
0.001 i
0.0001 -
10000-!
1000-!
100-
H ,;
1 I
0.1 i
0.01 i
0.001 ,
0.0001 -
I
0
T
u
Figure 4.10 Box-and-whisker plots of total available residue surface loadings (ng/cm2) for
chlorpyrifos, diazinon, c/'s-permethrin, ^raw^-permethrin, cypermethrin, and esfenvalerate.
65
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4.4 Transferable Residue Measurements
Transferable residue methods are intended to represent the surface loading that may be
transferred as a result of contact with the contaminated surface; that is, instead of complete
removal, they are typically intended to mimic transfer to skin during a single dermal contact with
a surface, where transfer is aided by only saliva, sweat, or the sebum layer on the skin.
Transferable residue loadings were measured in:
MNCPES using the CIS press sampler on floors and non-floor surfaces,
CTEPP using surface wipes with 2 mL 75% IPA on hard-surface floors and counters and
a PUF roller on carpeted floors,
CCC using the CIS press sampler on carpeted floors,
JAX using the CIS press sampler on carpeted floors,
CHAMACOS using the CIS press sampler on carpeted floors,
Test House using the CIS press sampler and a PUF roller skin on carpeted floors,
DIYC using the PUF roller on both hard-surface and carpeted floors, and
Daycare using the CIS press sampler and the PUF roller on carpeted floors.
The Modified CIS Surface Press Sampler was based on the original EL Sampler designed by
Edwards and Lioy to collect pesticides in house dust from carpeted floors (Edwards and Lioy,
1999; Hore, 2003). EPA modified the press sampler to use two 9-cm diameter sampling discs
for a total sampling area of 114 cm2 and eliminated the spring mechanism, henceforth it became
known as the Modified CIS Surface Press Sampler. Unlike vacuum methods that collect
household dust from all depths of the carpet pile and base, the surface press sampler is designed
to only contact and remove residue from the surface. The developers maintain that the sampler
replicates the collection efficiency of human skin and reflects transfer from single hand press
(Edwards and Lioy, 1999; Lioy etal., 2000), ignoring the inter- and intra-individual factors that
may affect transfer.
The PUF roller transferable residue sampler was developed to simulate the pressure applied to a
surface by a crawling child weighing 9 kg (7,300 Pa) (Hsu et al, 1990). The PUF roller consists
of a weighted roller fitted with a thick, moistened polyurethane foam (PUF) cover.
Modifications include using either a dry PUF roller cover or a thinner PUF skin. More details
can be found in the literature (Hsu etal, 1990; Lewis etal., 1994; Stout and Mason, 2003).
Discussion of the CTEPP surface wipe samples is included here rather than in Section 4.3
because of the small volume (only 2 mL) of isopropyl alcohol used. Also, it should be restated
that in CTEPP transferable residue samples were only collected in those homes and daycare
centers that reported recent pesticide use.
Limits of detection for each method and chemical are given by study above in Table 4.2.
Detection frequencies are given in Figure 4.11. The CIS Press and PUF roller results from
Daycare are not included (or further discussed) due to extremely poor detection frequencies, with
only one CIS and two PUF samples above the limit of detection.
66
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Pesticide Presence in Transferable Residues
Overall, the detection frequencies for transferable residues were substantially lower than
those for total available residues.
Chlorpyrifos was detected in greater than 75% of transferable residues in all of the
studies except MNCPES.
Cis- and frvms'-permethrin were detected in greater than 50% of the transferable residue
samples collected in CTEPP. These measurements were made in a subset of homes with
recent indoor applications of unidentified pesticides.
Transferable residues were rarely detected in field studies by the modified CIS surface
press sampler. In CHAMACOS, the detection frequency for chlorpyrifos was zero. In
MNCPES, the detection frequencies on the floor and on other surfaces were 8 and 5
percent, respectively. The only exception was the DIYC study, where the post-
application detection frequency for diazinon was greater than 50%.
The modified CIS press sampler was more successfully used in the laboratory studies
(Test House and Food Transfer studies) where residues were measured on all surface
types sampled.
CTEPP used IPA wipes with only 2 mL isopropanol instead of the 10 to 20 mL often
applied for total available residue measurements. It is likely that the amount of pesticide
residue recovered from the sampled surfaces is influenced by the amount of IPA applied
to the wipe. Other variables that should be considered include location sampled within
the room and last known pesticide application.
67
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Detection Frequency: Transferable Residues
100-
90-
80-
E 70-
0
ซ 60-
3
L. oO-
ii.
c
.2 40-
o
o
O OU-
0
20-
10-
n- i
I
!
!
':
\
;
1
!
i
1
I
I
:
:
^
i
i
i
i
i
i
i
i
i
i
i
i
i
i
i
i
i
5
j
1 :
:
, :
-
:
;
-
;
-
i
s
Chlorpyrifos TCPy
Diazinon
IMP
c-Perm
t-Perm Cyfluthrin
PRESS
H IPA
PRESS
3-NC IPA
nrmcTEpp-oH PUF
E^CTEPP-NC PUF
^^TESTHOUSE PUF
K5SDIYC PRESS
Figure 4.11 Detection frequencies for pesticides using transferable residue collection methods.
All results from the CIS Press samplers used in CHAMACOS were below the limits of
detection.
68
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Transferable Residues: Summary Findings
-th
Transferable residue loadings at the median and 95 percentile are given in Table 4.5 for all of
the pesticides that were detected across studies (complete summary statistics are listed in Tables
A.25 through A.29 in Appendix A). Transferable residue loadings of chlorpyrifos, diazinon, and
permethrin are depicted in lognormal probability plots and box-and-whisker plots in Figures 4.12
and 4.13, respectively.
The original CIS press sampler was designed to represent what adheres to the skin from a
single hand press onto a carpeted surface. The uses for the modified CIS surface press
sampler have expanded to include hard surfaces and longer contact times, contrary to its
intended use. The data in Table 4.5 suggest that the sensitivity of the modified CIS
surface press sampler is not adequate to measure typical residential pesticide residue
levels due to its low collection efficiency (estimated as less than 1%).
The mean transferable (2 mL IPA wipe) loadings were significantly different between
CTEPP NC and OH for c/'s-permethrin (p<0.01), ^raw^-permethrin (p<0.05), and diazinon
(p<0.01). The mean loadings were not significantly different for either chlorpyrifos
(ANOVA, p=0.12) or cyfluthrin (ANOVA, p=0.17).
Wipe sampling methods varied in the volume of IPA used as a solvent (Table 4.1). The
2-mL IPA wipes used in CTEPP produced surface loading values that were very similar
to those produced with the PUF roller (Figure 4.13). Since the PUF roller is a
transferable residue method, it appears that the amount of IPA applied to the wipe
determines the type of surface residue collected (i.e., total or transferable residue).
Interpretation of these results is complicated by other factors including recent application
and sampling location with respect to application.
69
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cth
Table 4.5 Median and 95 percentile values for transferable residues (ng/cm2) by study.
Study
MNCPES
CTEPP-NCha
CTEPP-OHha
TESTHOUSE
TESTHOUSE
PET
DIYC
Method
Press
IPA Wipe
IPA Wipe
PUF
Press
PUF
Press
Chlorpyrifos
P50
0.330
0.007
0.002
0.005
0.230
-
-
P95
0.420
0.140
0.760
0.15
6.90
-
-
Diazinon
P50
0.140
0.001
O.001
-
~
O.005
3.80
P95
1.13
0.51
0.05
-
~
24.0
c-Permethrin
P50
-
0.050
0.005
-
~
-
-
P95
-
1.500
0.780
-
~
-
-
/-Permethrin
P50
-
0.034
0.005
-
~
-
-
P95
-
1.600
0.790
-
~
-
-
Cyfluthrin
P50
-
O.007
O.007
-
~
-
-
P95
-
O.007
0.041
-
~
-
-
TCPy
P50
-
0.005
0.001
-
~
-
-
P95
-
0.024
0.033
-
~
-
-
IMP
P50
-
O.001
-
~
-
-
P95
-
0.007
-
~
-
-
--, pesticide not measured
"Homes only (daycares excluded)
70
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CHLORPYRIFOS
TRANSFERABLE RESIDUE LOADING (ng/cmZ)
DIAZINON
TRANSFERABLE RESIDUE LOADING (ng/cmZ)
.1 .2 .5 1 2
5 ID 20304050607080 90 35
Percent
* * * CTEPP-NC HOME COUNTER WIPE
tt tt n CTEPP-NC HOME FLOOR PUF
n n n CTEPP-NC HOME FLOOR WIPE
O O O CTEPP-OH HOME COUNTER WIPE
ffl ffi ffi CTEPP-OH HOME FLOOR PUF
V V V CTEPP-OH HOME FLOOR WIPE
.01
.1 .2 .5 1 Z
5 10 20 3D 4050 BO 70 BO 3D 95
Percent
* * * CTEPP-NC HOME COUNTER WIPE
tt tt tt CTEPP-NC HOME FLOOR PUF
n n n CTEPP-NC HOME FLOOR WIPE
000 CTEPP-OH HOME COUNTER WIPE
ffl ffl ffl CTEPP-OH HOME FLOOR PUF
V <0 V CTEPP-OH HOME FLOOR WIPE
CIS-PERMETHRIN
TRANSFERABLE RESIDUE LOADING (ng/cm2)
TRANS-PERMETHRIN
TRANSFERABLE RESIDUE LOADING (ng/cm2)
.1 .2 .5 1 2 5 ID 20 3040S06070 BO 90 95 99 99.9
Percent
* * * CTEPP-NC HOME COUNTER WIPE
tt ป tt CTEPP-NC HOME FLOOR PUF
d d d CTEPP-NC HOME FLOOR WIPE
000 CTEPP-OH HOME COUNTER WIPE
ffl ffl ffi CTEPP-OH HOME FLOOR PUF
-------
CHLORPYRIFOS
TRANSFERABLE RESIDUE LOADING (ng/cm2)
DIAZINON
TRANSFERABLE RESIDUE LOADING (ng/cm2)
CM
E
o
100-j
10-!
1 ~:
0.1 -
0.01 -,
0.001 1
0.0001 -
NC HU NC HU OH HM OH HU TEST TEST
IPA PUF IPA PUF PUF PRESS
0.01
0.001 !
0.0001 -
NCHM
IPA
NCHM
PUF
OHHM
IPA
OHHM
PUF
PET
PUF
CIS-PERMETHRIN
TRANSFERABLE RESIDUE LOADING (ng/cm2)
TRANS-PERMETHRIN
TRANSFERABLE RESIDUE LOADING (ng/cm2)
100-j
101
o 1 i
^ 0.1 -
0 ;
Q 0.01 -
3 ;
0.001 -
0.0001 -
]
100-
10-
T
Hi "
r~i 0.01 -
D.001 -
0.0001 -
I
T
I
NCHM
IPA
NCHM
PUF
OH HM
IPA
OH HM
PUF
NCHM
IPA
NCHM
PUF
OHHM
IPA
OHHM
PUF
CYFLUTHRIN
TRANSFERABLE RESIDUE LOADING (ng/cm2)
TCPY
TRANSFERABLE RESIDUE LOADING (ng/cm2)
E
o
J>
u
1
g
100 i
10-
1 -
0.1 -
0.01 -
0.001 -
0.0001 -
T ~^\
1 1
_]_ T
L-
100-
D
10-
1 -
0.1-
0.01 -
0.001 -
0.0001 -
-r-
T
Ep
^ u
NCHM
IPA
NCHM
PLF
OHHM
IPA
OHHM
PUF
NCHM
IPA
OHHM
IPA
OHHM
PUF
Figure 4.13 Box-and-whisker plots for transferable residue loadings for the most frequently
detected pesticides which include chlorpyrifos, diazinon, cis- and ^ram'-permethrin, cyfluthrin,
and TCPy.
-------
4.5 Spatial and Temporal Variability
Spatial and temporal variability were investigated in studies involving recent pesticide
applications, including:
Test House using IP A wipes, deposition coupons, CIS press sampler and PUF roller;
CPPAES using IPA wipes, deposition coupons, and the LWW sampler;
DIYC using IPA wipes and CIS press; and
Day care study using the IPA wipes.
In studies with a series of measurements over time, the interval of time between measurements
ranged from one to three days. In CPPAES, multiple rooms in ten homes were monitored for
two weeks post application. In DIYC, multiple surfaces in three homes were monitored for one
week. In the Test House, multiple surfaces in multiple rooms of a single house were monitored
for 21 days. The Day care study included multiple applications, each separated by one to three
months, in a single daycare facility. In addition to sampling main activity areas, some studies
also sampled less frequently contacted areas.
Figure 4.14 presents total available surface residue loadings measured in multiple locations in
multiple rooms over time in the Test House, in multiple rooms in ten homes in CPPAES, and on
multiple surfaces in three homes in DIYC. Figure 4.15 presents transferable residue
measurements over time in multiple rooms of the Test House and on multiple surfaces in three
homes in DIYC. Figure 4.16 presents total available residue measurements from the Daycare
study, collected immediately following applications on multiple surfaces in two rooms. Figure
4.17 presents spatial variability in deposition coupon loadings in the kitchen (application site)
and den (adjoining room) of the Test House following pesticide application.
Spatial and Temporal Variability: Summary Findings
Preliminary examination indicates that total available residue loadings decay at a slower
rate than airborne concentrations (See Figures 4.14 and 3.8).
In the Test House experiment, the transferable residue loadings appeared to decrease at a
faster rate than the total available residues (Figures 4.14 and 4.15). This may have
occurred because the pesticide residue became less available for transfer (for example,
due to an interaction with the surface or because the dried residue was less available for
transfer).
The transferable residues on the counters in DIYC (Figure 4.15) are nearly as high as
those on the floors immediately after application, suggesting translocation of the pesticide
from the site of application (assuming counters were not application surfaces).
Substantial variability within rooms (at times a 100-fold difference in loadings) is evident
in the Daycare data (Figure 4.16). Exposure estimates using measurements at a single
location based on an assumption of homogenous surface loadings may result in exposure
misclassification. The spatial variability points to the need for sampling of multiple
locations and perhaps for better resolution in the activity data that is gathered.
73
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Data from the Test House (Figure 4.17) show that surface loadings cannot be assumed to
be homogenous within a room.
In the CCC study, loadings on floors were generally higher than loadings on table tops.
In a published analysis of the MNCPES LWW wipe data, Lioy and colleagues (2000)
reported substantial variability in surface chlorpyrifos levels among different rooms.
74
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EPA Test House -Chlorpyrifos
CPPAES-Chlorpyrifos
3"-
o
20-
10-
Deposit Coup - Kitchen
I PA Wipe- Kitchen
Deposit Coup - Den
12 15 18 21
7-
6-
5-
1 4-
3-
2-
1-
0-1-1
0.0'
LWW
Deposition Coupons
IPA Wipes
Day
9
Day
12 15 18 21
DIYC -Diazinon
-IPA Wipe- Floor
-IPA Wipe- Playmat
-IPA Wipe- Counter
12 15 18 21
Day
Figure 4.14
Test House.
in DIYC.
Total available surface residue loadings measured in multiple rooms over time in the
in multiple rooms in ten homes in CPPAES, and on multiple surfaces in three homes
EPA Test House -Chlorpyrifos
DIYC-Diazinon
u 4'
-Press -Kitchen
-Press -Den
-PUF-Kitchen
-PUF-Den
12 15 18 21
Day
-Press- Floor
- Press - Counter
-Press- Playmat
9 12 15 18 21
Day
Figure 4.15 Transferable residue measurements overtime following an application from multiple
locations in multiple rooms of the Test House and multiple surfaces in three homes in DIYC.
75
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1000.0 -,
0.1
6/10
6/25
7/10
7/25 8/9
Sampling Date
9/23
-ext door
-restrooms
-center -x- table/sink --3K-- entryway
Figure 4.16 Total available residue measurements from the Day care study, collected immediately
following applications on multiple surfaces in two rooms in a single daycare facility. Solid Line
represents the preschool room and dashed line represents infant room
Dotted vertical line represents application.
Kitchen Deposition Coupon Loading
Right
Location in Row
Center
Left
Den Deposition Coupon Loading
Location in Row
Right
Dleft Q Center n Right
Figure 4.17 Spatial variability in deposition coupon loadings in the kitchen (application site) and
den (adjoining room) of Test House following pesticide application.
76
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4.6 Differences Related to Location
Regional Differences
Studies dating back to the Non-Occupational Pesticide Exposure Study (NOPES) from 1986 to
1988 (Whitmore et al, 1994) have reported regional differences in environmental pesticide
concentrations and loadings. Differences are thought to result from heavier use of insecticides in
warm weather climates with higher year round insect control problems than in colder regions
where hard winters help to curb insect populations.
Median diazinon surface dust loadings (ng/cm2) in home environments (daycares
excluded) were very similar (about 0.002 ng/cm2) across three states (NC, OH, and AZ,
Table 4.3), and the 95th percentiles were also somewhat similar (0.12, 0.31, and 0.18,
respectively). ANOVA analysis with Bonferroni adjustment for multiple comparisons
found no significant differences among the three locations. These dust measurements do
not provide evidence of the geographic variations consistent with geographic differences
in pest treatment practices reported by Colt (1998).
The overlapping distributions of pesticide concentrations in dust (ng/g) in the large
observational field studies in Arizona, North Carolina, and Ohio (Figure 4.4) suggest that
concentrations in dust may not be useful for determining region-specific pesticide use.
For transferable residues obtained with 2-mL IPA surface wipes, the mean chlorpyrifos
and cyfluthrin loadings were higher for CTEPP-NC compared to CTEPP-OH but not
statistically different (Figures 4.12, 4.13). However, the mean loadings were
significantly higher in NC for c/'s-permethrin (ANOVA; p<0.01) and fram'-permethrin
(ANOVA; p<0.05) and marginally significant for diazinon (ANOVA; p<0.10).
Analysis of surface wipe samples from the national, probability-based Child Care Center
study indicated no differences in the mean pesticide loadings among daycares in the four
Census regions (data not shown, Tulve et al, 2006).
Differences in surface sampling methods, year of the study, and time of year when
samples were collected make it difficult to examine any regional differences in surface
pesticide loadings in homes. The transferable residue measurements suggest higher
levels in NC than in OH, but no systematic differences are evident in dust concentrations
or total surface residue loadings, although JAX had much higher surface loadings than
any of the other studies without recent applications.
Urban vs. Rural
Lu and colleagues (2004) recently reported that at least one organophosphate pesticide was
present in the house dust of 75% of agricultural area homes but only 7% of metropolitan area
homes, suggesting different exposure pathways for children living in agricultural and
nonagricultural regions. While concerns about pesticides may be more obvious in farming and
other rural areas, widespread elevated pesticide residue levels have also been reported in highly
urbanized minority communities of New York City (Whyatt et al., 2002).
77
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Neither the median nor 95th percentile concentrations of chlorpyrifos measured in
CHAMACOS dust was substantially higher than the median and 95th percentile in the
other studies (Table 4.3). The assumption that children living in agricultural areas
experience higher exposures than children in nonagricultural regions is not supported by
these chlorpyrifos in dust measurements.
Relatively high pre-application surface loadings in some of the CPPAES homes (data not
presented) suggest possible contamination from pesticides applied in neighboring
apartments in close proximity (Hore, 2003). Alternatively, the high loadings may suggest
frequent treatments in those homes.
4.7 Influential Factors
As discussed above, the following factors appear to influence measured surface concentration or
loading values:
Collection Methods
The different types of collection methods are intended to have different collection
efficiencies to serve different purposes. Efficiencies for various methods have been
previously published.
Total residue methods (which use both solvent and mechanical action to remove residues
that may have penetrated into the surface) produce the highest values, followed by dust
methods, and then by transferable residue methods.
The low pesticide surface loadings obtained with 2 mL IPA wipes in both the NC and OH
CTEPP studies (comparable to loadings obtained with the PUF roller) suggest that the
amount of IPA applied to the wipe affects the amount of pesticide residue recovered.
The CIS Press does not appear to be useful for determining typical surface pesticide
residue loadings, for which it was never intended, because of its low collection efficiency
and small size.
Surface Types
Surface type has been shown to affect the collection efficiency of wipes. Recently
published NERL data (Rohrer et al, 2003) found that wiping from hard surfaces greatly
exceeded carpet, and tile generally exceeded hardwood. As stated by Rohrer, "Highest
pesticide recoveries were from tile with diazinon (59%), chlorpyrifos (80%), and
permethrins (52% cis; 53% trans) being the only pesticides recovered by wiping at
greater than 50% of the applied concentrations."
Sampling Locations
Despite evidence of translocation from direct application areas, the application area
surface residue loadings were generally higher than the play area surface residue loadings
in JAX.
78
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In the CCC study, floor residue loadings were typically higher than table top or desk top
loadings.
Experiments in the Test House showed high spatial variability in loadings in the room of
application (kitchen) and transport of pesticide residues to the adjoining room.
Results from the Daycare study showed substantial differences in surface loadings (up to
two orders of magnitude) at different locations in a day care center.
Occupant Activities
Surface chlorpyrifos loadings were reportedly lower in the CPPAES homes in which the
occupants performed cleaning activities and/or the homes that had high ventilation rates
(Hore, 2003).
Crack and crevice applications in the unoccupied Test House produced higher surface
loadings and longer decay times than the same type of application (albeit with less active
ingredient released) in the occupied CPPAES homes.
Pesticide Use Patterns
On a regional level, surface loadings in Jacksonville, Florida, an area likely to have year-
round pest control issues and high pesticide usage, were much higher than in any of the
other observational studies.
Within a given region, however, pesticide use information collected with questionnaires
or inventories may not correlate with measured surface values. Published results from
the MNCPES indicate that the residential pesticide use questions and overall screening
approach used in the MNCPES were ineffective for identifying households with higher
levels of individual target pesticides (Sexton etal., 2003).
4.8 Correlations among Soil, Wipes, and Dust
Analysis of CCC data (Tulve et al., 2006) found little correlation between surface wipe
loadings and soil concentrations for 16 common organophosphate and pyrethroid
pesticides.
In the CTEPP study, significant Spearman correlations between dust and soil
concentrations were observed with diazinon (r=0.26, p<0.01) and TCPy (r=0.21, p<0.05)
in NC homes and chlorpyrifos (r=0.28, p<0.01) and TCPy (r=0.20, p<0.05) in OH homes
(data not presented).
Identification of correlations is hindered by the low detection frequencies for many
pesticides in soil.
79
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4.9 Particle-Bound Pyrethroid Residues: Implications toward Exposure
The recent shift in commonly applied residential pesticides from organophosphate to pyrethroid
compounds carries with it important implications for human exposure. The chemical and
physical properties of a pesticide govern its behavior with respect to movement and fate. In
general, pyrethroids have properties that favor the particulate phase, resulting in transport
mechanisms preferentially involving dust rather than vapor. A tendency towards the particulate
phase also suggests a decreased relative importance of the inhalation route and an increased
relative importance of the dermal and indirect ingestion routes.
Pesticides applied in homes translocate from the point of application and deposit onto non-target
surfaces. Because human contact with target surfaces (e.g., cracks and crevices) is typically
obstructed or otherwise hindered, it is largely the movement of residues from the point of
application into the air and onto non-target surfaces that results in exposure. The movement of
residentially applied insecticides follows a complex and poorly understood process of
transformation and phase distribution and is influenced by several factors, namely: delivery
system, application surface type, solvent, formulation, physicochemical properties of the active
insecticide, and human and companion animal activity.
Overall, pyrethroids have similar physicochemical properties, and as a result, they display
similar behavior in the residential environment (Laskowski, 2002; Oros and Werner, 2005).
Pyrethroids generally have low vapor pressures and Henry's Law constants, thus they resist
volatilization and exist almost entirely in the particulate phase at room temperature. They have
high octanol/water partition coefficients (Kow), which suggests they tend to partition into lipids,
and very high water/organic carbon partition coefficients (Koc), which suggests that they also
tend to partition into organic matter. With these characteristics, pyrethroids can be expected to
bind readily to the particulate matter that comprises house dust. Particles resuspended by human
activity then act as the primary vector for pyrethroid transport and for human exposure.
Particle-phase contaminant transfer is strongly particle size dependent (Rodes etal., 2001).
Kissel etal. (1996) reported that dermal adherence of dry soil primarily involves particles in the
<150 |im size fraction. Assuming that house dust behaves similarly with respect to transfer, the
size fraction that preferentially adheres to skin not only comprises the bulk of house dust, but
also contains the highest pesticide concentrations. Rodes et al. (2001) reported that the <150 jim
size fraction comprises about 60% of house dust. Pesticide concentrations in house dust increase
with decreasing particle size, and are highest in the <25 jim size fraction (Lewis etal., 1999).
Because the surface-to-volume ratio similarly increases with decreasing particle size, pesticides
appear to be primarily attached to the surfaces of the particles (rather than trapped within).
Particle-bound movement and transfer of pyrethroids imply a decreased importance of the
inhalation route and an increased importance of the indirect ingestion route. Exposure of young
children, for whom indirect ingestion of residues from object- and hand-to-mouth activities is
particularly important, may be most strongly affected. Particle-bound residues may also have a
reduced potential for dermal absorption, as a consequence of being bound to the particle.
80
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5.0 DIETARY EXPOSURE MEASUREMENTS
5.1 Introduction and Data Availability
Diet can be a significant pathway of exposure to humans. Infants and young children may be
particularly vulnerable to exposure by dietary ingestion because they eat more than adults do
relative to their body weights. Foods may contain residues of pesticides because of intentional
agricultural applications or they may become contaminated during processing, distribution,
storage, preparation, and even consumption. The ingestion of residues on foods resulting from
contact with hands and surfaces during consumption as well as the ingestion of pesticide residues
while mouthing contaminated hands and objects are considered "indirect ingestion" pathways
and are the subject of the next chapter (Chapter 6.0). This chapter provides a comparative
summary of measurements of pesticides in duplicate diet samples and of estimated dietary
intakes. The sample collection methods for the studies that included duplicate diet
measurements are summarized in Table 5.1.
Among the large observational studies, duplicate diet samples were collected in NHEXAS-AZ,
MNCPES, and CTEPP. In CTEPP, food and beverage samples were collected at both homes and
daycares. Duplicate diet samples were also collected in three pilot-scale studies, CHAMACOS
(20 participants), DIYC (three participants), and JAX (nine participants).
The most common measure of dietary exposure was by composited duplicate diet
analyses (Table 5.1). This approach reduces study costs compared to analyzing
individual foods, but it increases the complexity of the sample analysis and produces
higher method detection limits.
Duplicate diet samples measure the pesticide residues in the children's foods after
processing and preparation by the caregiver. The samples, therefore, may include
residues from contaminated food handling surfaces in addition to the residues contained
in the food products. However, duplicate diets fail to capture the additional intake of
pesticides resulting from the child's activities before and during consumption, as
discussed in Chapter 6.
Duplicate plate samples were used for dietary measurements at the daycares in CTEPP.
The distinction between a duplicate plate and a duplicate diet (with the latter accounting
for uneaten foods) is typically more important for children than adults because significant
quantities of food may be left uneaten.
81
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Table 5.1 Dietary exposure sample collection methods for pesticides.
Study
NHEXAS-AZ
MNCPES
CTEPP
JAX
CHAMACOS
DIYC
Children
Ages
(years)
6-12
3-12
2-5
4-6
0.5-2
1 -3
Sample Type
Duplicate diet
Duplicate diet
Duplicate diet
(homes), and
duplicate servings
(at daycare centers)
Duplicate diet
Duplicate Diet
Duplicate diet,
each food collected
individually
Collection
after Indoor
Pesticide Use
No
No
No
Yes
No
Yes
Mass
Recorded
No
Yes
Home
samples
only
Yes
Yes
Yes
Collection
Period
24 hr
4d
48hr
24 hr
24 hr
24 hr
Sample Handling
Liquid and solid food
collected separately in
polyethylene
containers
Liquid and solid food
collected separately;
solid food split into
potentially "high
pesticide" foods and
"remaining" foods
Liquid and solid food
collected separately in
glass jars
Solid and liquid food
stored in polyethylene
containers
Liquid collected in
polycarbonate bottles
and solid food in
polyethylene zip
closure bags
Each food stored in
individual zip-loc
bags
Composite
Yes
Yes
Yes
Yes
Yes
No
Relevant Analytes
Chlorpyrifos, diazinon
Chlorpyrifos, diazinon, cis-
permethrin, /raws-permethrin
Chlorpyrifos, TCPy, diazinon, IMP
(Ohio only)
Chlorpyrifos, diazinon, cis-
permethrin, /raws-permethrin,
cyfluthrin
Chlorpyrifos, diazinon, cis-
permethrin, /raws-permethrin,
cyfluthrin
Diazinon
82
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5.2 Pesticide Presence
Table 5.2 presents the detection limits for the studies. The frequency of detection for the
selected pesticides is presented in Figure 5.1. The median and 95th percentile concentrations are
presented in Table 5.3. Data are presented in lognormal probability plots (Figures 5.2 and 5.3)
for the large observational field studies and box-and-whisker plots (Figures 5.4 and 5.5) for all of
the studies. Where food mass measurements are available (Table 5.1), both concentration and
intake (mass of compound ingested) are presented. Intake is defined as ng/day in keeping with
the dietary exposure algorithm of the Draft Protocol (Berry et a/., 2001) rather than as |ig/kg-
bw/day which would be more consistent with the reference dose (RfD) paradigm.
Reported method detection limits for chlorpyrifos ranged from 0.04 |ig/kg in JAX up to
1.7 jig/kg in CHAMACOS (Table 5.2).
Chlorpyrifos was detected in over 50% of the duplicate diet samples in MNCPES,
CTEPP, and JAX (Figure 5.1). The median chlorpyrifos concentrations in the MNCPES
and JAX diet samples were at least twice as high as in the CTEPP samples (Table 5.3).
Diazinon was not frequently detected in any of the studies except DIYC, a study in which
there had been prior indoor applications. The data from DIYC suggest that
contamination of food due to handling and surface contact is important in homes with
recent applications (see Section 6).
While detection of diazinon in food samples was typically below 30% (Figure 5.1),
detection immediately following crack and crevice application in DIYC was 100%.
The logplots (Figures 5.2 and 5.3) show that in the upper half of the distribution (between
the 50l and the 95th percentiles), higher concentrations of cis- and trans-permethrin were
measured in solid food in North Carolina homes than in North Carolina daycares or Ohio
homes or daycares.
Model simulations using DIYC data (results not presented) revealed that pesticides
transferred to food during contact with surfaces and handling by a child may increase
dietary intake significantly (over 60% under the modeled scenario).
Published results from the MNCPES (Clayton et al, 2003) showed that extant residue
databases can successfully be used to select samples for analysis, potentially reducing
costs by avoiding analyses of foods not likely to contain measurable levels. Care must be
taken, however, to avoid neglecting those residues that are transferred during handling.
Measurable levels of these particular pesticides were rarely detected in beverages in any
of these studies. Future studies with other such pesticides that are not expected to be
found in drinking water may consider eliminating this costly measurement.
Infants and children consume far fewer types of foods than do adults (while consuming
much more of certain foods) (NRC, 1993). Thus, the number of days of collection may
be less important for children than for adults.
The large potential for enzymatic degradation of pesticides (especially chlorpyrifos)
during food sample storage and during homogenation prior to analysis has not been
directly addressed by any studies under this program.
83
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Table 5.2 Limits of detection (ng/kg) for pesticides measured in duplicate diets.
Study
NHEXAS-AZ
MNCPES
CTEPP
JAX
CHAMACOS
DIYC
Compounds
Chlorpyrifos
1.0
0.26
0.08
0.04
1.4
-
Diazinon
0.7
0.3
0.08
0.04
1.2
0.36-1.25
c/5-Permethrin
a
0.2
0.08
0.02
4.5
-
/raws-Permethrin
-
0.2
0.08
0.02
2.9
-
Cyfluthrin
-
~
0.83
0.4
~
-
"Blank cells (--) indicate that the pesticide was not measured in the study.
cth
Table 5.3 Median and 95 percentile pesticide concentrations (jig/kg) measured in duplicate diet
food samples.
Study
NHEXAS-AZ
MNCPES
CTEPP-NC Home
CTEPP-NC Daycare
CTEPP-OH Home
CTEPP-OH Daycare
JAX
CHAMACOS
DIYC
Chlorpyrifos
P50
BDLa
0.53
0.2
0.1
0.2
0.1
0.38
BDL
-
P95
5.7
2.4
2.1
0.9
1.6
0.6
7.4
1.4
-
Diazinon
P50
1.8
BDL
BDL
BDL
BDL
BDL
BDL
BDL
0.17
P95
1.9
0.38
0.4
0.2
0.2
0.2
1.0
BDL
0.78
c/5-Permethrin
P50
b
-
BDL
BDL
BDL
BDL
0.29
BDL
-
P95
~
-
15.6
5.2
8.8
2.2
13
BDL
-
/raws-Permethrin
P50
~
-
BDL
BDL
BDL
BDL
0.22
BDL
-
P95
~
-
8.7
3.0
8.0
1.4
22
BDL
-
Cyfluthrin
P50
~
-
BDL
BDL
BDL
BDL
BDL
-
-
P95
~
-
0.9
BDL
BDL
BDL
3.6
-
-
a BDL, Below minimum detection limit
b Blank cells (--) indicate the pesticide was not measured in the study
84
-------
Detection Frequency: Solid Food
100-1
90-
80-
g 70-
o
I 6'
2 so-
il.
.2 40-
+*
o
o
"o 30-
O
20-
10
0
Chlorpyrifos Diazinon
o-Perm
t-Perm
Cyfluthrin
TCPy
I
IMP
NHEXAS-AZ
CTEPP-OHHOME
MNCPES ^mCTEPP-NC HOME ^ffl CTEPP-NC DAYCARE
CTEPP-OHDAYCARE mTTIJAX I^3CHAMACOS KXS DIYC
Figure 5.1 The detection frequency of pesticides measured in duplicate diet food samples.
85
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CHLORPYRIFOS
SOLID FOOD CONCENTRATION (ug/kg)
CHLORPYRIFOS
SOLID FOOD INTAKE (ug/day)
100 ;
.001 -Li-
.1.2 .51 2 5 10 ZD304Q 607080 9095 99 99.9
Percent
+ + + NHEXAS-AZ
* * * CTEPP-NC HOME
O O O CTEPP-OH HOME
XXX MNCPES
a n n CTEPP-NC DAYCARE
A A A CTEPP-OH DAYCARE
100
10 ;
.1.2.51 2 5 10 203040 607080 9095 99 99.9
Percent
XXX MNCPES
Z Z Z CTEPP-QH
Y Y Y CTEPP-NC
DIAZINON
SOLID FOOD CONCENTRATION (ug/kg)
DIAZINON
SOLID FOOD INTAKE (ug/doy)
100 ;
.1.2 .51 2 5 10 20 3040 6070 BO 9095 99 99.9
Percent
+ + -+ NHEXAS-AZ
* * * CTEPP-NC HOME
000 CTEPP-OH HOME
XXX MNCPES
n n n CTEPP-NC DAYCARE
A A A CTEPP-OH DAYCARE
.1.2.51 2 5 10 203040 607080 9095 99 99.9
Percent
XXX MNCPES Y V Y CTEPP-NC
Z Z Z CTEPP-OH
CIS-PERM ETHRIN
SOLID FOOD CONCENTRATION (ug/kg)
CIS-PERMETHRIN
SOLID FOOD INTAKE (ug/day)
100 ;
10 1
.001 -L-r
.1.2.51 2 5 10 20 3040 607080 9095 99 99.9
Percent
XXX MNCPES * * * CTEPP-NC HOME
nan CTEPP-NC DAYCARE o o o CTEPP-OH HOME
A A A CTEPP-OH DAYCARE
.1.2.51 2 5 10 203040 607080 9095 99 99.9
Percent
XXX MNCPES Y Y Y CTEPP-NC
Z Z Z CTEPP-OH
Figure 5.2 Lognormal probability plots of solid food concentrations (|ig/kg) and intakes (jig/day)
for chlorpyrifos, diazinon, and c/'s-permethrin from large observational field studies.
86
-------
TRANS-PERMETHRIN
SOLID FOOD CONCENTRATION (ug/kg)
TRANS-PERMETHRIN
SOLID FOOD INTAKE (ug/day)
100 1
10
1 1
.1 I
.01
001 "
I
I
I
I
Jt
#ฃ
I ije qC
I jJ^vO
XS^*
i
i
i
i
i
i
iii i
***
J
n
A
X X
;xxx
100 i
10 1
1 -
.1 :
.01
.001
1
Y
Y
4
*&
z
^,
3r
^#
^
w**
Y
Y
^?Z Z
frf
x
XX
v
^
.1.2 .51 2 5 10 ZD304Q 607080 9095 99 99.9
Percent
XXX MNCPES * * * CTEPP-NC HOME
D D D CTEPP-NC DAYCARE <> O O CTEPP-OH HOME
A A A CTEPP-OH DAYCARE
.1.2.51 2 5 10 203040 607080 9095 99 99.9
Percent
XXX MNCPES Y Y Y CTEPP-NC
Z Z Z CTEPP-QH
TCPY
SOLID FOOD CONCENTRATION (ug/kg)
TCPY
SOLID FOOD INTAKE (ug/doy)
100 I
10 1
100 1
.001 -ITr-
.1.2 .51 2 5 10 203040 807080 9095 99 99.9
Percent
* * * CTEPP-NC HOME
000 CTEPP-OH HOME
n n n CTEPP-NC DAYCARE
A A A CTEPP-OH DAYCARE
.001 -L^
.1.2.51 2 5 10 203040 607080 8085 99 99.8
Percent
Y Y Y CTEPP-NC Z Z Z CTEPP-OH
IMP
SOLID FOOD CONCENTRATION (ug/kg)
IMP
SOLID FOOD INTAKE (ug/day)
100 -
100 -
.1.2 .51 2 5 10 203040 6070 BO 9095 99 99.9
Percent
.01
000 CTEPP-OH HOME
A A A CTEPP-OH DAYCARE
.1.2.51 2 5 10 203040 607080 9095 99 99.9
Percent
z z z CTEPP-OH
Figure 5.3 Lognormal probability plots of solid food concentrations (|ig/kg) and intakes (jig/day)
for ^rara'-permethrin, TCPy, and IMP from large observational field studies.
87
-------
CHLORPYRIFOS
SOLID FOOD CONCENTRATION (ug/kg)
CHLORPYRIFOS
SOLID FOOD INTAKE (ug/day)
Z
UJ
o
o
o
.
8
O>
D
z
g
tc
K
i-
8
1000-:
100
o.H
0.01
0.001
0.0001 -
1 1 1 1 1 1 1
a MM NCHM NCDC OH MM OH DC JAX
DIAZINON
SOLID FOOD CONCENTRATION (ug/kg)
1000-i
100
10
0.1
0.01
0.001 -
0.0001 -
ii i i i i i
AZ UN NCHM NCDC OH HM OH DC OYC JAX
CIS-PERMETHRIN
SOLID FOOD CONCENTRATION (ug/kg)
1000-
100
10
1
0.1
0.01
0.001
0.0001 -
rj
\IIIir^
MN NCHM NCDC OH HM OH DC JAX
(ug/day)
Ld
z
D
"O
1?
UJ
1
Z
(ug/day)
^
1
1000 ;
100 :
10;
1]
0.1 ;
0.01 :
0.001;
0.0001 -
1000 i
100 i
10
1
D.1
0.01
0.001
0.0001 -
1000 i
100 i
ll
0.1 i
0.01 i
0.001 i
0.0001 -
T T I
I B B
I I
1 1 1
MN CTEPP-NC CTEPF-OH JAX
DIAZINON
SOLID FOOD INTAKE (ug/day)
T T 5 F^
111
I T
MN CTEPP-NC CTEPP-OH DIYC JAX
CIS-PERMETHRIN
SOLID FOOD INTAKE (ug/day)
-p
-p
90
I 2
MN CTEPP-NC CTEPP-OH
Figure 5.4 Box-and-whisker plots of solid food concentrations (|ig/kg) and intakes (jig/day) for
chlorpyrifos, diazinon, and c/5-permethrin across all studies.
88
-------
TRANS-PERMETHRIN
SOLID FOOD CONCENTRATION (ug/kg)
TRANS-PERMETHRIN
SOLID FOOD INTAKE (ug/day)
'S
^
FRATION (
Z
Ld
O
O
0
a>
a>
13
Z
O
F
K.
\
Z
Ld
U
0
U
'3
Dl
D
Z
O
1
CONCENTRA"
1000;
100;
10-i
1 -1
0.1;
0.01;
0.001 -i
0.0001 -
-p
I B i i 1 |
-L
1 III
MN NOHM NCDC OHHM OH DC JAX
TCPY
SOLID FOOD CONCENTRATION (uq/kq)
1000-
100 i
10-
1 ,
0.1 -
0.01-
0.001 -
0.0001 -
T I T T g
T I T
-L -L
i i i i i
NCHM NCDC OHHM OH DC JAX
IMP
SOLID FOOD CONCENTRATION (ug/kg)
1000-
100-
10-
1 -
0.1 -
0.01 -
0.001 -
0.0001 -
J T
1 1
OHHM OH DC
(ug/day)
LJ
z
D
"O
1?
UJ
1
Z
1000 ;
100 ;
10;
1]
0.1 ;
0.01 ;
0.001;
0.0001 -
1000 i
100 i
10
1
D.1
0.01
0.001
0.0001 -
(ug/day)
LU
I
_^
-p
B P
I M
MN CTEPP-NC CTEPP-OH
TCPY
SOLID FOOD INTAKE (uq/day)
I I
T P
J
CTEPP-NC CTEPP-OH
IMP
SOLID FOOD INTAKE (uq/day)
1000-
lOO-i
10;
1-1
0.1 ] J
0.01 -i
0.001 -i
0.0001 -
CTEPP-OH
Figure 5.5 Box-and-whisker plots of solid food concentrations (|ig/kg) and intakes (jig/day) for
fraw^-permethrin, TCPy, and IMP across all studies.
89
-------
5.3 Relative Importance of the Ingestion Route
The Stochastic Human Exposure and Dose Simulation (SHEDS) model (Zartarian etal., 2000)
prediction for dietary intake of c/'s-permethrin is compared to CTEPP measurements in Figure
5.6. The estimated proportion of aggregate exposure represented by dietary intake for CTEPP -
NC and CTEPP-OH children is from the CTEPP Report (Morgan et al., 2004) and is presented in
Figures 5.6 and 5.7, respectively.
An example of use of the SHEDS model to predict dietary intake of c/'s-permethrin in a
study population is shown in Figure 5.6. The dietary intake estimates may then be
compared to SHEDS model estimates of intake by other relevant routes to determine the
relative importance of the ingestion route.
Based on route-specific estimates (Figures 5.7 and 5.8), dietary ingestion represents the
dominant route of exposure for chlorpyrifos, diazinon, and permethrin in the CTEPP
study. Indirect ingestion, estimated based on dust and soil measurements, is a far greater
concern for the permethrin than for chlorpyrifos and diazinon in the CTEPP study.
The route that represents the dominant route of exposure (dietary ingestion) is also the
route with the lowest detection frequencies (approximately 2/3 of the values for
permethrin in CTEPP are nondetects), which increases the uncertainty in the estimates.
Substituting a fraction of the detection limit for values below the limit of detection may
have a disproportionate impact on the outcome.
1.5
45 50 55 60 65 70 75 80 85 90 95 100
SHEDS model - Observed data
Figure 5.6 Comparison of SHEDS model prediction for dietary intake of c/'s-permethrin
(|ig/kg/day) and CTEPP measurement data.
90
-------
6 "Mi
39%
Cliloipyrifos
TCP
38ฐ
trans-P
Diaz in on
cis-P
2,4-D
Inhalation
Dietary
Indirect
Figure 5.7 Estimated mean proportion of aggregate potential exposure for CTEPP-NC children
by exposure route. (TCP = 3,5,6-Trichloro-2-pyridinol; cis-P and trans-P = cis- and trans-
Permethrin; 2,4-D = 2,4-Dichlorophenoxyacetic acid.) From Morgan etal., 2004.
91
-------
4 "Mi
; s "Mi
Chlorpyrifos
TCP
37ฐ<
trans-P
2,4-D
Inhalation
Dietary
Indirect
Figure 5.8 Estimated mean proportion of aggregated potential exposure for CTEPP-OH children
by exposure route. (TCP = 3,5,6-Trichloro-2-pyridinol; cis-P and trans-P = cis- and trans-
Permethrin; 2,4-D = 2,4-Dichlorophenoxyacetic acid.) From Morgan et a/., 2004.
92
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6.0 INDIRECT INGESTION MEASUREMENTS
Children's ingestion of pesticide residues is not limited to residues in food and beverages
acquired during cultivation, food production, and in-home preparation. Indirect ingestion refers
to the ingestion of residues from hands or objects that enter the mouth, as well as to the ingestion
of residues transferred to food items by contact with the floor or other contaminated surfaces
during consumption. Indirect ingestion is believed to be an important route of exposure for
children because of their frequent mouthing activities and their unique handling of foods while
eating. Indirect ingestion may be the result of hand-to-mouth, object-to-mouth, or hand-to-
object-to-mouth activity. Indirect ingestion may be estimated using an approach that lumps
some of the exposure factors and activity patterns associated with indirect ingestion. This
simplified approach allows for assessment of indirect ingestion exposure based on measurement
data collected in the field and on factors that characterize the activities that lead to indirect
ingestion. In this approach, objects (including 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 addition, the items identified as most often mouthed
and/or eaten are assumed to represent the most significant sources of indirect ingestion exposure.
This section presents summary data for studies addressing the indirect ingestion route of
exposure (Table 6.1). Highlights of the data are presented below.
6.1 Characterizing Hand- and Object-to-Mouth Activities
Exposure models are based on two factors: how much pesticide residue is available for human
uptake and what human activities occur that would result in contact with and uptake of residues.
Hand-to-mouth and object-to-mouth activities are believed to directly impact ingestion of
pesticides among children through the indirect ingestion exposure route, but the relative
importance of these activities has not been established. In fact, the lack of empirical data
showing that either hand- or object-to-mouth activities appreciably affect exposure makes it a
hypothesis that has not yet been adequately addressed. The frequency of hand-to-mouth, object-
to-mouth, and/or combo-to-mouth contacts were quantified for children in the MNCPES and
CPPAES studies using a computer software system (Table 6.2). These studies used Virtual
Timing Device (VTD) software (Zartarian etal.. 1997) to quantify the children's normal daily
activities captured on videotape. The following are highlights of the data from these studies.
Assigning contact as either a hand-to-mouth or an object-to-mouth contact can cause the
hand-to-mouth and/or object-to-mouth contacts per hour to be underestimated. A combo-
to-mouth category that accounts for both simultaneous types of contacts may provide a
more accurate estimate of the indirect ingestion route of exposure.
An average frequency of 9 hand-to-mouth contacts per hour among 2 to 5 year olds is
recommended for regulatory risk assessments (US EPA, 2002). The CPPAES results
suggest that a higher value may be appropriate (Table 6.3).
93
-------
Figure 6.1 presents the average frequency of hand- and object-to-mouth contacts during
all eating and non-eating events. The highest hand-to-mouth frequency was observed in
CPPAES.
Factors affecting hand-to-mouth contact frequencies may include inclusion of eating
events, amount of time on tape, types of activities, number of children, and age range.
An analysis of hand-to-mouth activities in MNCPES has been published by Freeman et
al. (2001). They reported that hand-to-mouth activities were significantly more frequent
(t test, P<0.05) among girls than among boys.
The MNCPES data also showed that hand-to-mouth and object-to-mouth activities were
more frequent (Mann-Whitney, p<0.05) indoors than outdoors (Freeman etal., 2001).
Published studies have quantified the hand- and object-to-mouth activities of young
children (Zartarian et al, 1998; Reed et al, 1999; Tulve et al, 2002; Freeman et al,
2005). These studies suggest that young children may exhibit higher hand-to-mouth
and/or object-to-mouth contacts than older children and adults.
Standardized approaches for quantifying the activity patterns of children are needed in
order to compare results among different studies.
6.2 Residue Loadings on Mouthed Objects and Removal by Mouthing
For indirect ingestion estimates, objects that are commonly mouthed are identified in the field
and the residue loadings on these objects are measured. Objects commonly mouthed by
preschoolers were identified in CTEPP. Pesticide loadings on toy surfaces were measured in the
CHAMACOS and CPPAES studies. Data on the fraction of residues that may be removed by
mouthing of fingers was collected in the laboratory-based Transfer studies using non-toxic
fluorescent surrogates.
Objects commonly mouthed by preschoolers were identified in CTEPP. These items
were typically toys and food-related items (Table 6.4).
Chlorpyrifos loadings on toy surfaces were much higher following recent applications, as
evidenced by the higher values in CPPAES than in CHAMACOS (Table 6.5). Loading
on toy surfaces in CPPAES (Table 6.5) were greater than surface loadings as measured
by deposition coupons (Table 4.4).
Measurements from CPPAES (data not presented) suggest that surface wiping of plush
toys yields only a small fraction of the total amount of chlorpyrifos absorbed into the toys
(as measured by extraction). Indirect ingestion among children who regularly mouth soft
toys may thus be underestimated by toy surface wipes.
In "transfer off experiments conducted with a fluorescent tracer (riboflavin) as part of
the Transfer studies, removal from skin via the mouthing of 4 fingers was measured.
Eight replicates were performed with each of three participants (data not presented), with
0 to 26% of the tracer removed per replicate (loss was significantly different from zero in
only one-half of the replicates).
94
-------
Table 6.1 Collection methods for the transfer of pesticide surface residues to food or objects.
Study
Food
(Surfaces to
Foods)
Food
(Tile to Foods)
DIYC
CHAMACOS
CPPAES
Transfer
Study Type
Laboratory
Laboratory
Field
Field
Field
Laboratory
Age Range
n/a
n/a
1-3 yr
0.5-2.5 yr
<5yr
Adult
Sampling Details
1, 10, & 60 min
contact between food
and contaminated
surfaces
10 min contact
between food and
contaminated tile
surface
Handled leftover food,
untouched leftover
food, food press
Teething ring or small
ball provided 1.5 days
before sampling
Plush toy given to
child to handle for 1 1
days
Mouthing removal of
fluorescent tracer
Collected After
Application
Yes-1 hr
following
applications
Yes-1 hr
following
applications
Yes
No
Yes
n/a
Sample Handling
Foods extracted
immediately
following
sampling
Foods extracted
immediately
following
sampling
Collected in
individual zip
closure bags
Stored at -20 C
until analysis
No information
Video-
fluorescence
imaging
Composite
Sample
No
No
Yes
No
No
No
Insecticides
Measured
Chlorpyrifos
Diazinon
Heptachlor
Isofenphos
Malathion
Permethrin
Chlorpyrifos
Cyfluthrin
Cypermethrin
Deltamethrin
Fipronil
Malathion
Permethrin
Diazinon
Chlorpyrifos
Diazinon
Permethrin
Chlorpyrifos
Surrogate
(Riboflavin)
Comments
Surface wipes were
collected. The
influence from
contact force and
duration were
evaluated
Surface wipes and
deposition on foil
coupons collected
Foods leftover from
meal were combined
into two types of
samples; i.e., all
handled foods
combined, all
untouched foods
combined
Surface of toys
wiped
Surface of toys
wiped; whole toys
extracted
Many measurements
at detection level of
technique
n/a, Not applicable
95
-------
Table 6.2 Videotaped children's hand- and object-to-mouth activity details.
Study
MNCPES
CPPAES
N
19
10
Age
(years)
3 to 12
2 to 5
Sampling
Location
Homes
(inside
and/or
outside)
Homes
(inside or
outside)
Time Period
4 consecutive
hours in normal
daily activities
4 hours on Day
2 following
crack and
crevice
application of
chlorpyrifos
Method of Analysis
Methods of Reed et
al., 1999
Computer software
(Virtual Timing
Device)
Quantified 4 hours
of videotape for
both hands
Activity of
Interest
Hand-to-mouth
Object-to-mouth
Hand-to-mouth
Object-to-mouth
Availability
Freeman et al. ,
2001.
Freeman et al. ,
2004.
Table 6.3 Videotaped hand-to-mouth and object-to-mouth counts.
Study
CPPAES (2 to 5 yrs)
Tulve a < 24 month old
Tulve >24 month old
MNCPES (3 to 12 yrs)
MNCPES boys indoor
MNCPES girls indoor
Hand-to-Mouth
Mean
19.8
18
16
5.7
4.7
8.1
Median
16
12
9
2.5
NR
NR
Object-to-Mouth
Mean
8.4
45
17
1.8
1.0
2.6
Median
6.4
39
9
0
NR
NR
Eating Events
Unspecified
Excluded
Excluded
Unspecified
Unspecified
Unspecified
NR, Not Reported
aTulve data (Tulve et al., 2002) included for comparison.
Table 6.4 Objects commonly mouthed by preschoolers in CTEPP.
Category
Toys
Food-Related Items
Miscellaneous
Items
Plastic rings/bracelets, stuffed animals, balls, walkie talkie, building
doll, bubble blower
; blocks,
Ice pops, candy wrapper, water bottle, utensils, napkins, drinks
Plastic blow-up chair, pens, greeting cards, clothing, CDs, towels, blanket, pets
96
-------
cth
Table 6.5 Median and 95 percentile pesticide loadings (ng/cm2) measured on toy surfaces.
Study
CHAMACOS
CPPAES
Chlorpyrifos
P50
BDLa
3.0
P95
0.15
21
Diazinon
P50
0.034
b
P95
0.27
-
c/5-Permethrin
P50
BDL
-
P95
0.053
-
/raws-Permethrin
P50
BDL
-
P95
0.072
-
cyfluthrin
P50
BDL
-
P95
BDL
-
a BDL, Below minimum detection limit
b Blank cells (--) indicate the pesticide was not measured in the study
40
oc
oo -
30 -
k.
fj 25
c
o
ซ> on _
Frequency
_k _i |>
o cn c
5 -
0 -
Hand-t
o-Mouth
I
' ' '
Objec
p CPPAES 2-5 yr.
B Tulve < 2 yr.
in Tulve >2 yr.
H MNCPES Girls <13yr.
in MMPDPQ Rn\/e < 1Q \/r
Mj>S55?3
:-to-Mouth
Figure 6.1 Comparison of the median hand-to-mouth and object-to-mouth contacts per hour
among CPPAES and MNCPES children. MNCPES values are means instead of medians. Tulve
data (Tulve etal., 2002) included for comparison.
97
-------
6.3 Transfer of Pesticide Residues to Food
The experiments reported here (Appendix B, Food Transfer Studies) used loadings that
were near to or greater than the 95th percentile for loadings in most of the recent field
studies (See Table 4.4).
Higher pesticide transfer to food occurred from hard, smooth surfaces, such as hardwood
flooring; lower transfer occurred from carpet. For example, 33% of chlorpyrifos was
transferred from wood flooring to an apple, whereas the amount transferred from carpet
was not enough to be reliably quantified (Table 6.6).
Bologna, a moist and fatty food, removed a higher percentage of pesticides from a hard
surface than did fruit leather, a low-fat and low-water content food (Table 6.7).
Comparison (Table 6.8, Figure 6.2) of measured dietary intake of diazinon (incorporating
excess contamination due to handling) with estimates predicted by the Children's Dietary
Intake Model (CDIM) suggests that use of fixed values for transfer efficiencies and for
activity factors in the model may result in inaccurate estimates of daily dietary intake.
Model-predicted estimates generally under-predicted intake.
Diazinon concentrations in untouched leftover food were compared with those in handled
leftover food in DIYC. Daily dietary intake estimates accounting for contamination due
to handling by children were often double the intake estimates based on untouched food
(Total Measured Dietary Intake vs. Duplicate Diet Intake, Table 6.8), indicating that
duplicate diets may significantly underestimate actual intake in homes that have high
surface pesticide residue loadings.
Food transfer studies have provided evidence that transfer of pesticide residues from
surfaces to foods is dependent on such factors as pesticide class, food type, contact
duration, and contact force (data not presented).
Applied force produced a considerable increase in transfer efficiency (data not
presented). Moreover, the effect of applied force was even more dramatic as contact
duration increased.
98
-------
Table 6.6 The transfer efficiency (percent transfer, mean ฑ sd) of pesticide residues from treated
surfaces to foods (relative to transfer to IP A wipes), after a 10-min contact duration (Food
Transfer Studies).
Pesticide
Chlorpyrifos
(21-38ng/cm2)
Diazinon
(20-30 ng/cm2)
Malathion
(33-45 ng/cm2)
c/5-Permethrin
(40-53 ng/cm2)
/raws-Permethrin
(43-55 ng/cm2)
Sampling Media
Bologna
Apple
Cheese
Bologna
Apple
Cheese
Bologna
Apple
Cheese
Bologna
Apple
Cheese
Bologna
Apple
Cheese
N
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
Treated Surface
Ceramic Tile
36 ฑ20
18 ฑ5
7ฑ0
41 ฑ5
35 ฑ8
20 ฑ7
60 ฑ21
132 ฑ74
94 ฑ33
19 ฑ15
26 ฑ13
BQL
23 ฑ20
29 ฑ14
BQL
Wood Flooring
15 ฑ4
33 ฑ8
26 ฑ1
29 ฑ0
50 ฑ5
103 ฑ 18
31ฑ1
18 ฑ1
52 ฑ37
70 ฑ86
3ฑ1
BQL
10 ฑ1
5ฑ0
BQL
Carpet
BQLa
BQL
BQL
BQL
BQL
BQL
BQL
212 ฑ60
400 ฑ 173
BQL
BQL
BQL
BQL
BQL
BQL
JBQL = Below Quantitation Limit
99
-------
Table 6.7 The transfer efficiency (percent transfer, mean ฑ sd) of pesticide residues from a
treated ceramic tile surface to various foods and to an IPA Wipe (Food Transfer Studies).
Pesticide Class
Organophosphate
Pyrethroid
Phenylpyrazole
Pesticide
Chlorpyrifos
(123 ng/cm2)
Malathion
(193 ng/cm2)
Cyfluthrin
(143 ng/cm2)
Cypermethrin
(185 ng/cm2)
Deltamethrin
(2 11 ng/cm2)
Permethrin
(147 ng/cm2)
Fipronil
(203 ng/cm2)
Sampling Media
Bologna
Apple
Fruit Leather
20-mL IPA Wipe
Bologna
Apple
Fruit Leather
20-mL IPA Wipe
Bologna
Apple
Fruit Leather
20-mL IPA Wipe
Bologna
Apple
Fruit Leather
20-mL IPA Wipe
Bologna
Apple
Fruit Leather
20-mL IPA Wipe
Bologna
Apple
Fruit Leather
20-mL IPA Wipe
Bologna
Apple
Fruit Leather
20-mL IPA Wipe
N
o
5
o
3
3
o
J
o
J
3
3
3
3
o
J
3
3
o
5
o
6
3
3
o
J
3
3
3
3
o
J
3
3
o
5
o
6
3
o
J
% Transfer
64.7 ฑ15.0
27.5 ฑ8.0
13. 5 ฑ2.0
99.8 ฑ10.8
74.9 ฑ17.7
29.7 ฑ8.4
8.7 ฑ2.7
104.6 ฑ10.9
47.8 ฑ13.4
24.0 ฑ3.4
0.7 ฑ0
108.5 ฑ12.1
45.0 ฑ10.7
21.5 ฑ6.9
0.6 ฑ0
101.5 ฑ7.0
39.2 ฑ6.1
22.2 ฑ5.1
2.4 ฑ0.2
83.7 ฑ4.3
44.0 ฑ11.5
19.8 ฑ7.1
1.3 ฑ0.1
100.8 ฑ4.8
43. 3 ฑ1.6
30.9 ฑ14.8
2.0 ฑ1.7
103. 8 ฑ10.4
100
-------
Table 6.8 The measured and predicted ingestion (ng/day) of diazinon from the DIYC.
Child
1
2
3
Sampling
Day
Pre
1
4
5
6
7
8
1
2
3
4
5
2
8
Duplicate Diet
Intake
ng/d
197
1063
280
270
140
563
253
455
233
212
260
188
95
412
Excess Dietary
Intake3
ng/d
384
1270
220
501
322
536
160
156
95
373
414
189
90
344
Total Measured
Dietary Intake b
ng/d
581
2333
500
771
462
1099
413
611
328
585
674
377
185
756
CDIM Predicted
Dietary Intake ฐ
ng/d
357
1271
281
333
142
702
397
663
402
392
612
278
509
940
Percent
Difference d
%
-39
-46
-44
-57
-69
-36
-4
9
23
-33
-9
-26
175
24
a Measured surface-to-food and hand-to-food transfer due to handling of foods, concentration in handled but uneaten
portion extrapolated to eaten portion.
bDuplicate Diet intake plus Excess Dietary intake.
0 Estimated by deterministic model using fixed transfer efficiency and activity values.
dPercent Difference = 100*[(CDIM Predicted Intake - Total Measured Intake)/(Total Measured Intake)].
101
-------
2500-1
2000-
^ 1500-
n
fl> 1000-
u
-------
6.4 Indirect Ingestion of Dust and Soil
The potential indirect ingestion exposure (ng/day) can be estimated using indoor floor dust
(ng/g) and outdoor soil sample concentrations (ng/g) together with the child's body weight (kg),
estimated daily dust ingestion rate (g/day), estimated daily soil ingestion rate (g/day), and the
estimated oral bioavailability. In CTEPP, the daily dust ingestion rates were calculated based on
questionnaire responses related to specific activities of each child in the month prior to field
sampling. These activities included pacifier use, teething, mouthing body parts, licking floors,
and placing toys or other objects into the mouth. The daily soil ingestion rates were estimated
based on how often a child played with sand/dirt and ate dirt, sand, or snow. Many of these
parameters have very high uncertainty associated with them. The daily dust and soil ingestion
rates were each estimated as 0.025, 0.050, or 0.100 g/day. The indirect exposure estimates,
presented in Table 6.9, showed the following:
Indirect ingestion estimates for the permethrin isomers were much higher than for
chlorpyrifos or diazinon, largely because permethrin was measured at much higher
concentrations in floor dust (Figures 4.6 and 4.7).
The differences between NC and OH in mean permethrin concentrations in dust suggest
potential regional differences in indirect ingestion.
Table 6.9 The estimated exposures (ng/day) of NC and OH preschool children in the CTEPP
study to chlorpyrifos, diazinon, and permethrin through indirect ingestion.
Pesticide
Chlorpyrifos
Diazinon
c/5-Permethrin
/raws-Permethrin
State
NC
OH
NC
OH
NC
OH
NC
OH
N
117
116
118
116
120
116
120
102
Mean
15.5
27.8
21.7
49.1
220
61.5
222
61.2
SD
29.0
164
81.9
367
670
139
698
153
GM
6.2
3.0
1.6
1.5
48.4
21.3
42.7
16.6
GSD
1.3
1.5
2.0
1.9
1.6
1.4
1.7
1.5
Min
0.3
0.2
-------
6.5 Indirect Ingestion: Summary
As shown in the bulleted lists of observations from these laboratory and observational studies,
progress has been achieved in identifying and quantifying a number of factors that are believed
to potentially impact indirect ingestion among children.
Videotape analysis of children's hand- and object-to-mouth contacts has provided
evidence that hand-to-mouth activities were more frequent: among infants and toddlers
than among older children, among girls than among boys, and at indoor locations than at
outdoor locations.
Objects most commonly mouthed by preschoolers were identified as typically being toys
and food-related items.
High chlorpyrifos loadings were measured on toy surfaces following routine residential
application.
Fluorescent tracer experiments found that removal from skin (at very high tracer
loadings) by mouthing was highly variable. Additional information is still needed on the
fraction of residue transferred from the hands to mouth during typical mouthing events at
dermal loading levels observed in field studies.
At high surface loadings, pesticide transfer to food was greater from hard, smooth
surfaces than from carpet.
In homes with high surface pesticide residue loadings, residue concentrations in foods
handled by children were often twice as high as concentrations in leftover unhandled
foods.
The transfer of pesticide residues from surfaces to foods appears to be dependent on such
factors as pesticide class, food type, contact duration, and applied force.
Indirect ingestion estimates for permethrin were much higher than for chlorpyrifos or
diazinon, largely because permethrin was measured at much higher concentrations in
floor dust.
104
-------
7.0 DERMAL EXPOSURE MEASUREMENTS
The ability to accurately estimate surface-to-skin transfer of contaminants from intermittent
contacts remains a critical and missing link in pesticide exposure and risk assessments. For
children's exposures, transfer of chemicals from contaminated surfaces such as floors and
furniture is potentially significant. Once on the skin, residues and contaminated particles can be
transferred back to the contaminated surface during subsequent contact, lost by dislodgement or
washing, or transferred into the body by percutaneous absorption or hand-to-mouth activity. A
better understanding of the relevant factors influencing transfers from contaminated surfaces to
skin and the resulting dermal loading will reduce uncertainty in exposure assessment. Areas of
uncertainty with respect to dermal transfer are related to the important factors that impact
transfer, whether or not a steady-state condition is reached, and the conditions that affect
removal. Laboratory tests were conducted by NERL using nontoxic fluorescent tracers to
evaluate significant transfer parameters. The results of these tests are described in this section
(Section 7.1).
Measurements of pesticide residues on children's hands have been performed in a number of
studies. Both hand wipe and hand rinse methods have been used. The collection efficiency of
different wipe and rinse methods can be expected to differ, with an eight-fold difference reported
between hand rinses and hand wipes in one study (Hore, 2003). Furthermore, differences in
dermal exposure and dose due to free pesticide residue versus particle- (or dust-) bound
pesticides may be important in interpreting the results. Results of wipes and rinses in selected
studies are summarized in tables and figures presented below (in Section 7.2).
An alternative approach for estimating dermal exposure is the cotton garment surrogate. Similar
to the approach used for measuring occupational exposures to pesticides, cotton garments, which
can consist of a bodysuit and/or socks, have been used in three studies that are reported below
(Section 7.3).
Important Factors Affecting Transfer
Dermal exposure to surface residues is dependent on human activities that result in contact with
surfaces and the physicochemical and mechanical mechanisms of transfer of residues from the
surface to the skin. Several factors are commonly believed to affect transfer (Table 7.1). These
factors can be grouped as characteristics of the surface (including contaminant loading, type of
surface, and temperature), of the contaminant (including formulation, physical state, particle size,
vapor pressure, viscosity, water solubility, lipophilicity, and being particle-bound), of the skin
(including moistness and contact area), of contact (including duration, force, frequency, motion,
and interval), and of protection measures (including clothing and hand washing).
Many of these have previously been investigated, though not necessarily specific to pesticides
and skin. Kissel et al. (1996) reported moisture content andparticle sizes of soil to be significant
factors affecting the process of adherence to skin. Rodes et al. (2001) reported that only about
1/3 of the palm contacted surfaces during a press and that dust-to-skin transfer increased with
hand dampness, decreased as surface roughness increased, and decreased with consecutive
presses (requiring about 100 presses to reach equilibrium). Brouwer et al. (1999) reported that
105
-------
whereas only 4-16% of the surface area of the palm of the hand is covered with a fluorescent
tracer after one contact with a hard surface, about 40% becomes covered after twelve
consecutive contacts. At least three studies have investigated the transfer of pesticides from
surfaces to hands (measured using IPA wipes of hands.). Briefly, Lu and Fenske (1999) reported
transfer of chlorpyrifos residues to hands to be 0.04 to 0.26% from carpets and 0.69% from
furniture. Camann et al. (1996) examined transfer from nylon carpet to dry or moistened hands
and reported transfers ranging from 0.7-1.3% for chlorpyrifos, 2.9-4.8% for pyrethrin I, and
1.5-2.8% for piperonyl butoxide. Clothier (2000) examined transfer of the same residues from
vinyl sheet flooring and reported transfers of 1.5% to dry and 4.4-5.2% to wet skin for
chlorpyrifos, 3.6% (dry) and 8.9- 11.9% (wet) for pyrethrin I, and 1.4% (dry) and 4.1-4.8%
(wet) for piperonyl butoxide.
7.1 Laboratory Fluorescent Measurement Studies
Laboratory tests were performed to evaluate transfer efficiencies (TEs) of nontoxic fluorescent
tracers (as surrogates for pesticide residues) from common household surfaces to hands (Cohen
Hubal etal, 2005). The laboratory studies evaluated parameters affecting surface-to-hand
transfer, including surface type, surface loading, contact motion, pressure, duration, and skin
condition in two sets of experiments (Table 7.2). The data from the laboratory fluorescent
measurement studies are presented in Tables 7.3 to 7.6 and Figures 7.1 and 7.2.
Tests comparing fluorescent tracers with pesticides (Figure 7.1) showed that the transfer
of riboflavin to PUF rollers and CIS disks is similar to that of chlorpyrifos, and that the
transfer of Uvitex is similar to that of the pyrethroids permethrin and esfenvalerate.
Laboratory studies using fluorescent tracers riboflavin and Uvitex OB (Tables 7.3 to 7.6)
indicated that tracer type, surface type, contact motion, and skin condition were all
significant factors. Transfer was greater with laminate (over carpet), smudge (over
press), and sticky skin (over moist or dry). Contact duration and pressure (force) were
not important factors.
Comparison of "first contact" to "repeated contact" results (Table 7.4) suggests that the
effect of surface type appears to diminish with repeated contact while the effect of skin
condition (moist vs. dry) appears to increase with repeated contact.
Laboratory surface loadings (0.2 and 2.0 jig/cm2) were much higher than the median
values of 0.032 and 0.0014 jig/cm2 measured by deposition coupons (Table 4.4) after
crack and crevice application of chlorpyrifos in the Test House and CPPAES studies,
respectively,
In the initial tracer experiments with high surface loadings, dermal loadings appear to
reach a maximum by the fourth or fifth contact (data not presented), suggesting a
saturation effect. In the follow-up experiments with lower surface loadings (Figure 7.2),
dermal loadings appear to increase linearly through the seventh contact, suggesting that at
lower surface loadings, more contacts may be required to reach steady state.
In "transfer off experiments described earlier (Section 6.2), the amount removed from
fingers by mouthing was significantly different from zero in only half of the replicates.
106
-------
Table 7.1 Factors commonly believed to affect dermal transfer.
Category
Surface
Contaminant
Skin
Contact
Protection
Parameter
Level of contamination
Type of surface: roughness, carpet vs. hard
surface
Formulation
Physical state: solid, liquid
Particle characteristics: particle size
distribution, moistness
Liquid characteristics: viscosity and related
properties
Physical properties of active ingredient:
vapor pressure, water solubility, lipophilicity
Moistness
Contact area
Frequency: number of contacts or objects
Interval between contacts
Motion: press, smudge, drag
Clothing: use, area covered, material
Hand washing: frequency
Source
Goede et al., 2003; This Report
Brouwer et al, 1999; Rodes et al, 2001
Marquarte/a/., 2005
Marquarte/a/., 2005
Kissel et al, 1996
Marquarte/a/., 2005
This Report
Camanne/a/., 1996; Clothier, 2000; Rodes et
al, 2001; This Report
Brouwer et al, 1999
Brouwer et al, 1999; Rodes et al, 2001; This
Report
Camanne/a/., 1996;
LuandFenske, 1999;
Marquarte/a/., 2005
This Report
Categories and parameters modified from Marquart et al, 2005.
Table 7.2 Study parameters tested in surface-to-skin transfer experiments in the Characterizing
Pesticide Residue Transfer Efficiencies study.
Parameter
Tracer
Skin Condition
Surface Type
Surface Loading
Contact Motion
Contact Duration
Contact Pressure
Contact Number
Initial Experiments
Riboflavin a
Dry, Moist, or Sticky
Carpet or Laminate
2 or 10 ug/cm2
Press or Smudge
2 sec or 20 sec
7 or 70 kg/cm2
Multiple
Refined Experiments a
Riboflavin b or Uvitex ฐ
Dry or Moist
Carpet or Laminate
0.2 or 2 ug/cm2
Press or Smudge
d
-
Multiple
a Refined experiments added Uvitex, reduced the loading levels, and reduced the number of parameters tested
b Relatively water soluble
0 Relatively water insoluble
d Blank cells indicate that parameter was not investigated in the study
107
-------
Table 7.3 Skin loadings (mean, standard deviation) measured following surface-to-skin transfer experiments (initial experiments).
(Source: Cohen Hubal etal, 2005.)
Contact
Hand condition
Dry
Moist
Sticky
Surface type
Carpet
Laminate
Surface loading
High
Low
Skin loading, ug/cm2, average (SD) a
1
2
o
6
4
5
0.3 (0.6)
0.4 (0.4)
0.5 (0.5)
0.6 (0.5)
0.5 (0.3)
0.4 (0.3)
0.9 (0.6)
1.0 (0.6)
1.3 (0.8)
1.3 (0.7)
0.7 (0.6)
1.2 (0.7)
1.5 (0.7)
1.6 (0.8)
1.8 (0.8)
0.4 (0.5)
0.8 (0.7)
1.0 (0.8)
1.2 (0.9)
1.3 (1.0)
0.5 (0.5)
0.8 (0.6)
1.0 (0.7)
1.2 (0.7)
1.0 (0.6)
0.6 (0.6)
1.0 (0.7)
1.2 (0.8)
1.4 (0.8)
1.4 (0.9)
0.3 (0.3)
0.6 (0.5)
0.8 (0.6)
0.9 (0.7)
0.9 (0.7)
Skin loading, ug/cm2 (without sticky hand condition), average (SD)
1
2
3
4
5
0.3 (0.6)
0.4 (0.4)
0.5 (0.5)
0.6 (0.5)
0.5 (0.3)
0.4 (0.3)
0.9 (0.6)
1.1 (0.6)
1.3 (0.8)
1.3 (0.7)
0.4 (0.6)
0.7 (0.7)
0.8 (0.8)
1.0 (0.9)
0.9 (0.9)
0.3 (0.2)
0.6 (0.4)
0.8 (0.5)
0.9 (0.5)
0.8 (0.4)
0.5 (0.6)
0.8 (0.7)
1.0 (0.7)
1.2 (0.8)
1.1 (0.8)
0.2 (0.2)
0.4 (0.3)
0.5 (0.4)
0.6 (0.4)
0.6 (0.4)
1 Three subjects provided three independent replicates for each experiment
108
-------
Table 7.4 Statistical analysis results (p-values) from initial surface-to-hand transfer experiments (Riboflavin).
Analysis
Tracer
Surface Type
Surface Loading
Contact Motion
Pressure
Duration
Skin Condition
First contact (ANOVA)
Transfer efficiency (%)
Loading (ug/cm2)
p<0.1
p>0.1
p<0.001 a
p<0.05
p<0.05
p<0.05
p>0.1
p>0.1
p>0.1
p>0.1
p<0.001
p<0.05
First contact, sticky hand excluded (ANOVA)
Transfer efficiency (%)
Loading (ug/cm2)
p>0.1
p>0.1
p<0.001
p<0.1
p>0.1
p<0.05
p>0.1
p>0.1
p>0.1
p>0.1
p< 0.001
p>0.1
Repeated contact (Mixed-Effects Model)
Loading (ug/cm2)
p>0.1
p<0.001
p<0.001
p>0.1
p>0.1
p<0.001
Repeated contact, sticky hand excluded (Mixed-Effects Model)
Loading (ug/cm2)
p>0.1
p<0.001
p<0.01
p>0.1
p<0.1
p<0.001
Contact
Number
p<0.001
p<0.001
1 Bold text indicates the parameter is significant.
Table 7.5 Statistical analysis results (p-values) from refined, follow-up surface-to-hand transfer experiments (Riboflavin and Uvitex).
Analysis
Tracer
Surface Type
Surface Loading
Contact Motion
Pressure a
Duration a
Skin Condition
Contact
Number
First Contact (ANOVA)
Transfer efficiency (%)
Loading (ug/cm2)
p<0.05b
n O 1
p<0.05
p<0.05
p<0.01
p=0.001
p<0.1
p<0.001
p>0.1
p>0.1
Repeated Contact (Mixed-Effects Model)
Loading (ug/cm2)
p<0.01
n O 1
p<0.001
p<0.001
p<0.05
p<0.001
a Pressure and duration not included in the follow-up experiments.
bBold text indicates the parameter is statistically significant at p<0.05.
109
-------
Table 7.6 Evidence of importance of factors tested across surface-to-skin transfer experiments.
Parameter
Tracer
Skin Condition
Surface Type
Surface Loading
Contact Motion
Contact Duration
Contact Pressure
Contact Number
Initial Experiments
-
O
00
0
00
00
Refined Experiments
0
O
0
O
~
-
~ not tested
OO not found to be significant
O mixed results or marginally significant at p<0.10
significant at p<0.05 in all tests
Transfer Efficiency (% Transfer) for Pesticides and Fluorescent Tracers
100
10
1 --
0.1
0.01
V V
V V
V V
V V
v x-
V \>
laminate
carpet
Transfer to Aqueous
Wipe
laminate
carpet
Transfer to PDF Roller
laminate
HDiazinon
QChlorpyrifos
Qcis-Permethrin
Strans-Permethrin
Q Esfenvalerate
DRiboflavin
DUvitex OB
carpet
Transfer to C18 Press
Disk (20 sec)
Figure 7.1 Comparison of transfer efficiencies of fluorescent tracers and pesticides from laminate
and carpet surfaces to various sampling media.
110
-------
Loading by Contact No., FollowUp Experiment
Loading = high
Analyte=Rfboflavfn
Loading by Contact No., FollowUp Experiment
Loading = high
Analyte=Uvitex
2400-
2200-
2000-
1800-
ฃJ 1500-
E
-e 1400-
a>
E, 1200-
i 1000-
O
ฐ 800-
c
m 500-
400-
200-
0-
-200-
-T
JL
D
1
T
7]
^
2
-.
I
--
_._
_^
_
_
; ^ i i I
3
4
5
6
7
Contact Number
2400-
2200-
2000-
1800-
1600-
1400-
1200-
1000-
800-
600-
400-
200-
0-
-200-
-p
0
I i
L i '
1
I
m
i
ซ
I
h~^
1 2 3 4 5 e
Contact Number
.
I
7
1300:
1200-
1100:
1DOO:
900-
800:
700:
600-
500-
400-
300:
200-
100-
0-
-100-
Loading by Contact No., FollowUp Experiment
Loading = low
Analyte=Rfboflavfn
Loading by Contact No,, FollowUp Experiment
Loading = low
Analyte=Uvitex
345
Contact Number
1300-
1200-
1100-
1000-
900-
800-
700-
600-
500-
400-
300-
200-
100-
0-
-100-
"
_^
T
|
1
1
It
2
i
b
3
V
-T-
m
I
i
"i n
*
^ I I
4567
Contact Number
Figure 7.2 Hand loading by contact number, from the refined, follow-up experiments using
Riboflavin (left panels) or Uvitex (right panels) with 2 ug/cm2 (high) (top panels) or 0.2 ug/cm2
(low) (bottom panels) surface loadings. In these particular box-and-whisker plots, means and
outliers (below 5th or above 95th percentiles) are represented by dots.
Ill
-------
7.2 Measurements of Pesticides on Hands by Wipe and Rinse Methods
Measurements of pesticide residues on children's hands have been performed in the MNCPES,
CTEPP, CPPAES, PET, and DIYC studies. Collection efficiencies may vary among studies for a
number of reasons. The method of wiping the surfaces of the hand may vary when performed by
different researchers or by study participants themselves. Hand rinses may be more effective
than hand wipes. Whether the method is a hand wipe or hand rinse, collection efficiency may
differ for free pesticide residues versus particle-bound residue. Most of the data presented in this
section were collected with hand wipes, except for MNCPES, in which rinses were collected.
Both hand wipes and rinses were collected in CPPAES (with mean hand rinse to hand wipe
ratios ranging from 4.1 to 7.8 by home). The amount of isopropanol used to collect the hand
wipes/ rinses varied by study. A major issue associated with interpreting results of these
measurements is the amount of a pesticide on the surface of skin that is never absorbed into the
bloodstream. Solvents may extract some of pesticide from top layers of skin, though the extent
of extraction will be a function of many factors including pesticide properties.
Methods
In CTEPP, hand wipe samples were collected from 257 preschool children using cotton sponges
(SOF-WICK gauze pad; 4" x 4" - 3 ply; Johnson & Johnson) that were pre-cleaned and wetted
with 2 mL of 75% isopropanol. The adult caregiver wiped the front and back of both hands of
the child. A total of four wipe samples were collected over a 48-hr period (two per day, one
before lunch and dinner, before washing hands). Samples were composited (combined) before
analysis. The MNCPES hand rinses were collected at home from 102 children on day 1 of the 7-
day monitoring period. A technician placed each of the child's hands into a separate zip-closure
bag containing 150 mL of isopropanol. Each hand's sample was analyzed separately. The
feasibility portion of the PET study collected hand wipes on multiple days from two children
after a granular application of diazinon to the lawn by the homeowner. The cotton sponges
(SOF-WICK gauze pad; 4" x 4" - 6 ply; Johnson & Johnson) were presoaked with 20 mL of
isopropanol. Each child wiped the front and back of each hand. A total of five samples were
collected from each child and each was analyzed separately. The CPPAES hand wipe samples
were collected from 10 children on multiple days following a professional crack and crevice
application of chlorpyrifos. Separate swabs that were wetted with an unreported amount of
isopropanol were used to wipe the front and back of each hand. A small number of hand rinse
samples were also collected. The DIYC study collected hand wipes on multiple days from three
children after a crack and crevice application of diazinon. Each of two gauze pads, pre-wetted
with 10 mL of isopropanol, was used to wipe both hands. The two wipes were extracted and
analyzed as one sample. In all studies, the surface area of the children's hands was measured.
Results
Table 7.7 summarizes the detection limits for the studies. The median and 95th percentile
concentrations are presented in Table 7.8. Individual hand loading measurements are presented
in Tables 7.9. Relationships among populations and locations are illustrated in Figures 7.3 to 7.9
and highlighted below.
112
-------
In the large observational field studies (Figure 7.3, Table 7.8), the loadings of
chlorpyrifos on children's hands measured with rinses in MNCPES were higher than the
loadings measured with wipes in the other studies.
For all compounds, the hand loadings measured with hand wipes in the large
observational field studies did not differ substantially (Figure 7.3, Table 7.8).
Median chlorpyrifos loadings on children's hands (Figure 7.4) were much higher in
CPPAES, where homes had recent crack and crevice applications, than in the large
observational CTEPP and MNCPES studies.
Median diazinon loadings on children's hands in the small, pilot-scale PET (lawn
application) and DIYC (crack and crevice application) studies were much higher than in
the large observational field study CTEPP (Figure 7.4).
Comparison of hand rinse and hand wipe samples collected from the same participants in
CPPAES suggests that hand rinses were more effective at removing residues (Table 7.9).
Hand rinses may be more efficient than hand wipes at removing chlorpyrifos from the
skin, but no information is available on which method better reflects the amount of
pesticide that is either absorbed (dermal absorption) or potentially transferred to the
mouth (indirect ingestion).
In the CTEPP study, the median chlorpyrifos hand loadings were higher in NC than OH
(at both homes and daycares), suggesting greater chlorpyrifos usage in NC than in OH.
Permethrin levels were only slightly higher in NC than in OH (Figure 7.4).
At residential levels observed in CTEPP, median hand wipe-to-surface loading ratios
reach or exceed 1 for the pesticides of interest (Figure 7.5). Please note that floor wipe
loadings were measured using an IPA wipe method that was not as efficient as typical
wipe methods (Section 4.4).
A strong relationship is evident in Figure 7.6 between CTEPP hand loadings measured at
homes and those measured at daycares for chlorpyrifos (R2=0.47), diazinon (R2=0.44),
and permethrin (R2=0.41). The relationship is weak for the degradation product TCPy
(R2=0.03).
There was a strong relationship between children's hand wipe loadings and adult hand
wipe loadings for chlorpyrifos (R2=0.64; P=0.77), diazinon (R2=0.77; P=0.81), and
permethrin (R2=0.49; P=0.65) measured in CTEPP (Figure 7.7), despite largely different
activity patterns between children and adults.
Based on regressions of CTEPP hand wipe measurements on either floor dust or floor
wipe measurements for chlorpyrifos, diazinon, and permethrin (Figures 7.8 and 7.9),
better relationships were observed between hand wipe and floor dust measurements
(Figure 7.9) than between hand wipe and floor wipe measurements (Figure 7.8).
113
-------
Table 7.7 Limits of detection (ng/cm2) for dermal measurements by compound and study.
Study
NHEXAS-AZ
MNCPES
CTEPP
CPPAES
CPPAES
DIYC
PET
Sample type
Hand wipe
Hand rinse
Hand wipe
Hand wipe
Hand rinse
Hand wipe
Hand wipe
Chlorpyrifos
0.004
0.06
0.003
NAb
NAb
~
-
Diazinon
0.016
0.08
0.003
-
-
0.02
0.01
c-Permethrin
a
-
0.003
-
-
~
-
/-Permethrin
-
-
0.003
-
-
~
-
'Blank cells indicate that the pesticide was not measured in the study.
3 Detection limit information unavailable.
Table 7.8 Median and 95th percentile values of pesticide hand loadings (ng/cm2) measured by hand rinse (HR) or hand wipe (HW) in
the large observational field studies.
Study
NHEXAS-AZ
MNCPES
CTEPP-NC hb
CTEPP-NC d
CTEPP-OH h
CTEPP-OH d
Type
HW
HR
HW
HW
HW
HW
Chlorpyrifos
P50
0.01
0.07
0.02
0.02
0.01
0.01
P95
0.1
0.3
0.3
0.1
0.2
0.1
Diazinon
P50
0.015
0.07
0.003
0.01
0.003
0.003
P95
0.1
0.1
0.1
0.1
0.1
0.04
c-Permethrin
P50
a
-
0.1
0.1
0.03
0.04
P95
-
-
1.5
0.3
0.8
0.6
/-Permethrin
P50
-
-
0.1
0.04
0.03
0.03
P95
-
-
1.3
0.3
0.8
0.8
Cyfluthrin
P50
-
-
0.03
0.03
0.03
-
P95
-
-
0.4
0.3
0.1
-
TCPY
P50
-
-
0.02
0.01
0.01
0.01
P95
-
-
0.1
0.03
0.03
0.03
IMP
P50
-
-
-
-
0.003
0.003
P95
-
-
-
-
0.02
0.02
a Blank cells indicate that the pesticide was not measured in the study.
b CTEPP: h = home, d = daycare
114
-------
Table 7.9 Comparison of chlorpyrifos and diazinon loadings (ng/cm2) on children's hands measured with hand rinse (HR) and hand
wipe (HW) methods.
Study
CPPAES
(chlorpyrifos)
PET
(diazinon)
DIYC
(diazinon)
Participant
Child 1 (4 yr)
Child 2 (4 yr)
Child 3 (4 yr)
Child 4 (2 yr)
Child 5 (4 yr)
Child 6 (3 yr)
Child 7 (3 yr)
Child 8 (3 yr)
Child 9 (4 yr)
Child 10 (4 yr)
Child 1 (6 yr)
Child 2 (10 yr)
Child 1 (2 yr)
Child 2 (3 yr)
Child 3 (1 yr)
Pre-Appl a
HR
b
0.53
~
0.57
0.09
~
2.3
0.21
~
-
-
~
-
-
-
HW
-
-
~
-
-
0.57
-
-
0.07
0.43
0.01
0.7
0.06 d
-
-
Day 1
HR
-
5.2
11
-
-
~
-
-
~
-
-
~
-
-
-
HW
-
-
~
0.79
0.3
0.36
0.17
0.1
0.08
0.43
0.6 c
0.7C
-
-
-
Day 3
HR
-
18
2.3
-
-
~
-
-
~
-
-
~
-
-
-
HW
-
-
~
0.34
1.4
0.67
0.25
0.01
~
0.68
0.9
0.6
-
0.03
0.10
0.10b
Day 5
HR
-
1.6
~
-
-
~
-
-
~
-
-
~
-
-
-
HW
-
-
~
0.81
0.28
0.35
0.22
0.02
0.09
0.5
0.14de
0.08 ef
-------
CHLORPYRIFOS
HAND LOADING (ng/cm2)
DIAZINON
HAND LOADING (ng/cm2)
.1.2 .5 1 2 5 10 20304050607080 90 95 99 99.9
Percent
XXX MNCPES * * # CTEPP-NC HOME
O O O CTEPP-NC DAYCARE O O O CTEPP-OH HOME
A A A CTEPP-OH DAYCARE
.1.2.51 2 5 10 20304050607080 9095 99 99.9
Percent
* * * CTEPP-NC HOME
ซ ซ ซ CTEPP-OH HOME
D D D CTEPP-NC DAYCARE
A A A CTEPP-OH DAYCARE
CIS-PERMETHRIN
HAND LOADING (ng/cm2)
TRANS-PERMETHRIN
HAND LOADING (nซ/cm2)
.1.2 .5 1 2 5 10 20 30405D6O7O BO 90 95 99 99.9
Percent
* * * CTEPP-NC HOME
000 CTEPP-OH HOME
a a a CTEPP-NC DAYCARE
A A A CTEPP-OH DAYCARE
.1.2 .5 1 2 5 10 2O 3D405O6070 SO 9O 95 99
Percent
* * * CTEPP-NC HOME
000 CTEPP-OH HOME
D D D CTEPP-NC DAYCARE
A A A CTEPP-OH DAYCARE
TCPY
HAND LOADING (ng/cmZ)
IMP
HAND LOADING (ng/cm2)
.1.2 .5 1 2 5 10 20 3040506070 BO 90 95 99 99.9
Percent
-------
CHLORPYRIFOS
HAND LOADING (ng/cm2)
DIAZINON
HAND LOADING (ng/cm2)
CM
I
cn
c
O
O
100-
10-
1 -
0.01 -
0.001 -
100
10
0.1 -
0.01 -
0.001 -
MN NC HM NC DC OH HM OH DC CPPAES CPPAES
HR HW
I I I I I I
NC HM NC DC OH HM OH DC PET DIYC
CIS-PERMETHRIN
HAND LOADING (ng/cm2)
TRANS-PERMETHRIN
HAND LOADING (ng/cm2)
CM
E
u
Q
<
O
11
0.1 i
0.01 -,
0.001 -
I I
NC DC OH HM
100-
10-
0.01 -
0.001 -
OH DC
NCHM
NCDC
OHHM
OH DC
TCPY
HAND LOADING (ng/cm2)
IMP
HAND LOADING (ng/cm2)
100 i
CM
E
u
\
Dl
C
Q
<
O
0.1 i
0.01
0.001 -
100-
10-
1 -
0.1 -
0.01 -
0.001 -
NC HM
NCDC
OH HM
Figure 7.4 Comparison of hand loadings across studies. MNCPES data are hand rinses,
CPPAES includes both hand rinses (HR) and hand wipes (HW), all others are hand wipes.
117
-------
o
K.
Ratio of Handwipe Loading to Floor Wipe Loading
10000]"
1000-
100
Ratio of Handwipe Loading to Dust Loading
1
0.1
0.01
0.001 -
I
I
10000]
1000-
100
10
1
0.1
0.01
0.001 -
Chlorpyrifos Diazmon cPermethrin tPermethrin
Chlorpyrifos Dfazfnon cPermethrin tPermethrin
Figure 7.5 Ratios of hand wipe loading to floor wipe loading (left panel) and hand wipe loading
to dust loading (right panel) for pesticides in CTEPP.
118
-------
CHLORPYRIFOS
DIAZINON
500-
^ 50^
CM
I
0.005 7
0.00054
o a
* ฐ
O.OO05 O.O5 5 500
Daycare Hand Loading (ng/cm2)
500:
50:
0.5:
0.05-
0.005-
0.0005-1
" *ฐ
O.OOO5 O.O5 5 5OO
Daycare Hand Loading (ng/cm2)
CIS-PERMETHRIN
CYFLUTHRIN
500:
5O-
0.5-
0.05-
0.005-
.0005 J
500-
50-
E
o
~g5 5.
ฐ en
T-ฐ ฐ ฐ 1 ฐ-5
* ^ฐAg 0 D i 0.05-
1 0.005-
tfP ฐ o
0.0005-
o
*
O
CO
ฐฐ ^
0.0005 0.05 5 500
Daycare Hand Loading (ng/cm2)
0.0005 0.05 5 500
Daycare Hand Loading (ng/cm2)
1
TCPy
i
O.OOO5 O.O5 5 50O
Daycare Hand Loadfng (ng/cm2)
O.OOO5 O.O5 5 5OO
Daycare Hand Loading (ng/cm2)
Figure 7.6 Relationship between children's hand loadings measured at CTEPP homes and
daycares. Coefficients of determination (R2) and slopes (P) for log (base 10) values: chlorpyrifos
(R2=0.47; P=0.91), diazinon (R2=0.44; P=0.81), permethrin (R2=0.41; P=0.72), cyfluthrin
(R2=0.02; P=0.19), TCPy (R2=0.03; P=0.54), and IMP (R2=0.31; p=0.54).
119
-------
CHLORPYRIFOS
DIAZINON
500-
4
ฃ 0.05:
0.005
0.0005-
0.0005 0.05 5
Adult Hand Loading (ng/cm2)
O
500-
50-
5-
0.5-
^ 0.05-
" 0.005-
0.0005-
0
ฐ
500
0.0005 0.05 5
Adult Hand Loading (ng/cm2)
500
CIS-PERMETHRIN
CYFLUTHRIN
J
CT
C
=0
500:
50^
0.05
0.005
0.0005 -^
0.0005 0.05 5
Adult Hand Loading (ng/cm2)
E
o
^
500-
BO-
0.5-
0.05-
0.005-
0.0005-
500
* ง
0.0005 0.05 5
Adult Hand Laadmg (ng/cm2)
500
TCPy
^
~l
*&
=5
5
g
ฃ
S
5
soo-
so
5
O.5-
0.05
O.OO5-
D.ODOS^
^^
4
"i-
5
0*^ "c
'ffi^^K' 0 ^
%^E^^I9& ^
s^Pf fi
SOD-
5D-
5-
O.5-
0.05
O.OOS-
O.DOO5-
o
J|iฐ
O.OOO5 O.O5 5
Adult Hand Loading (ng/cm2)
O.OOO5 O.O5 5
Adult Hand Loading (ng/cm2>
Figure 7.7 Relationship between hand loadings among children and adults in CTEPP.
Coefficients of determination (R2) and slopes (P) for log (base 10) values: chlorpyrifos (R2=0.64;
P=0.77), diazinon (R2=0.77; P=0.81), permethrin (R2=0.49; P=0.65), cyfluthrin (R2=0.20;
P=0.61), TCPy (R2=0.30; P=0.47), and IMP (R2=0.28; p=0.63).
120
-------
Com pound =Chlorpyrifos
Compound=Diazinon
100.000:
10.000:
CM
c 1.000:
1
O
31
U)
.0. 0.100:
0.010:
0.001 -
+
+
x+++++
+ *
*+ ++ + *
10.000:
1.000-
CM
c?
| 0.100-
V
_O.
1
0.010-
0.001 -
+
+ +
+
1 *+
0.0001 0.0010 0.0100 0.1000 1.0000 10.0000
Floor Wipe (Home). ng/cm2
0.0001 0.0010 0.0100 0.1000 1.0000
Floor Wipe (Home). ng/cm2
Compou nd =c-Permethrin
Com pound=t-Permethrin
100.000:
10.000-
N
I
" 1.000-
1
^r
.9- 0.100-
!
i
0.010-
0.001
+
,
+ +
+
+ +
+ """
+
+ ++ +
+ + +
+ ++ +
100.000:
10.000-
N
E
U
\
" 1.000-
1
'
Q. 0.100-
*
1
I
0.010-
0.001 -
+
-f
+
+
+ ++
+
+ +
+ + +
+ +
. + +
+ +
+ +
+ +
+
+ +
0.0001 0.0010 0.0100 0.1000 1.0000 10.0000
Floor Wipe (Home), ng/cm2
0.0001 0.0010 0.0100 0.1000 1.0000 10.0000
Floor Wipe (Home), ng/cm2
Figure 7.8 Relationship between hand wipe measurements and floor wipe measurements in
CTEPP. Coefficients of determination (R2) and slopes (P) for log (base 10) handwipe loadings
regressed on log (base 10) floor wipe loadings are as follows: chlorpyrifos (R2=0.38; P=0.64),
diazinon (R2=0.46; 0=0.64), c/'s-permethrin (R2=0.54; 0=0.78), and ฃr
-------
Com pound =Chlorpyrifos
Compound=Diazinon
100.000.
10.000-
CM
c 1.000
t
o
1
.Q. 0.100-
0.010:
"*
10.000:
0.100
0.0001 0.0010 0.0100 0.1000 1.0000 10.0000
Floor Dust Loading (Home), ng/cm2
0.0001 0.0010 0.0100 0.1000 1.0000 10.0000
Floor Dust Loading (Home). ng/cm2
Compound=c-Permethrin
Compound=t-Permethrin
10.000-
E
1.000
t
.3. 0.100
0.001 -
10.000:
CN1
1.000
t
.S. 0.100
I
0.001 -
0.010 0.100 1.000 10.000 100.000
Floor Dust Loading (Home), ng/cm2
0.010 0.100 1.000 10.000 100.000
Floor Dust Loading (Home), ng/cm2
Figure 7.9 Relationship between hand wipe measurements and floor dust measurements in
CTEPP. Coefficients of determination (R2) and slopes (P) for log (base 10) handwipe loadings
regressed on log (base 10) floor dust loadings are as follows: chlorpyrifos (R2=0.71; P=0.78),
diazinon (R2=0.69; 0=0.61), c/'s-permethrin (R2=0.72; P=0.86), and ฃr
-------
7.3 Measurements with Cotton Garments
The US EPA Office of Pesticide Programs uses a transfer coefficient approach to assess
children's residential exposures to pesticides. The transfer coefficient approach was developed
to assess occupational exposure in an agricultural setting, using empirically-derived dermal
transfer coefficients to aggregate the mass transfer associated with a series of contacts with a
contaminated medium. Dermal exposure sampling using a surrogate-skin technique such as a
patch sampler or a whole-body garment sampler is conducted simultaneously with surface
sampling for a specific activity, and a dermal transfer coefficient is then calculated. This
transfer coefficient can then be used to estimate exposure for a similar activity by collecting only
surface samples (Fenske, 1993), assuming that transfer is unidirectional (from surface to skin)
and linear with time. Only limited research has been conducted to develop transfer coefficients
for children in residential and daycare settings. Data were collected in the Daycare study (Cohen
Hubal et a/., 2006), JAX, and CPPAES with cotton garments. The data are presented in Tables
7.10 to 7.12 and Figures 7.10 to 7.12.
Comparison of mean chlorpyrifos loadings on socks in JAX and CPPAES (Table 7.10)
with surface loadings (Table 4.4) suggests that higher surface loadings do not necessarily
correspond to higher sock loadings across studies. It also suggests that perhaps activity
levels influence transfer.
The median chlorpyrifos loading on socks after a three-hour period in CPPAES was only
about twice as high as the median loading after a one-hour period in the same
environment (Table 7.10). This suggests that transfer to socks may not be linear with
time, and again points towards the importance of activity levels.
Bodysuit esfenvalerate loadings in the Daycare study were typically higher in the
mornings, corresponding to higher group activity levels at that time (Figure 7.10).
Depletion of surface loadings by morning activities is unlikely but was not tested.
Multiple regression analysis of Daycare data suggests that body section (arms, legs, lower
torso, and upper torso), relative activity level, and age group are all important predictors
of bodysuit loadings (Table 7.11).
The statistical significance of activity (Table 7.11), even when controlling for age group,
suggests that activity level within age groups may be as important as age-related
differences.
The between- and within-person variability (GSD) in dermal exposures in the daycare
setting (Table 7.12) is similar to what has been reported in agricultural/industrial settings.
High within-person variability (compared to between-person variability) in cotton
garment loadings (Table 7.12) suggests that factors related to changing environmental
conditions and to differences in structured activities may be more important than child-
specific characteristics.
The relative standard deviations (%) of esfenvalerate loadings on cotton garment sections
(Figure 7.11) were typically higher among infants during the morning sessions and
among preschoolers during the afternoon sessions. This suggests that the structured
123
-------
activities may have had a stronger influence on the observed variability than surface
loadings in the respective rooms.
Infants had 1.5 times as many hand wipe values (36%) above the MDL as preschool
children (24%), consistent with the higher bodysuit loadings, perhaps reflecting greater
contact with the floor surface. Figure 7.12 illustrates that among the hand wipes above
the MDL, infants typically had higher loadings, with greater variability.
The association between hand wipe samples above the limit of detection and average
body suit loadings was statistically significant (Spearman rho = 0.54, p < 0.05, data not
presented).
124
-------
Table 7.10 Pesticide loading (ng/cm2) on cotton garments worn by children in three studies.
Study
Day care
CPPAES
JAX
CHAMACOS
Compound
Esfenvalerate
Chlorpyrifos
Chlorpyrifos
Diazinon
Esfenvalerate
Cyfluthrin
c/5-Permethrin
/raws-Permethrin
Chlorpyrifos
Diazinon
Esfenvalerate
Cyfluthrin
cw-Permethrin
/raws-Permethrin
Garment
Type/Section
Arms
Legs
Lower Torso
Upper Torso
Bottom
Knee
Leg
Sock (1 hr)
Sock (3 hr)
Sock
Sock
Sock
Sock
Sock
Sock
Union Suit
Sock
Union Suit
Sock
Union Suit
Sock
Union Suit
Sock
Union Suit
Sock
Union Suit
Sock
Age
9-13 mo
24-38 mo
9-13 mo
24-38 mo
9-13 mo
24-38 mo
9-13 mo
24-38 mo
2-5 yr
2-5 yr
2-5 yr
2-5 yr
2-5 yr
4-6 yr
4-6 yr
4-6 yr
4-6 yr
4-6 yr
4-6 yr
6-10 mo
2 1-27 mo
6-10 mo
2 1-27 mo
6-10 mo
2 1-27 mo
6-10 mo
2 1-27 mo
6-10 mo
2 1-27 mo
6-10 mo
2 1-27 mo
6-10 mo
2 1-27 mo
6-10 mo
2 1-27 mo
6-10 mo
2 1-27 mo
6-10 mo
2 1-27 mo
6-10 mo
2 1-27 mo
6-10 mo
2 1-27 mo
N
26
28
26
28
26
28
26
28
7
14
14
14
14
9
9
9
9
9
9
10
10
9
10
10
10
9
10
10
10
9
10
10
10
9
10
10
10
9
10
10
10
9
10
%Det
92
100
100
93
100
100
96
100
100
100
100
100
100
100
33
22
0
44
100
100
100
89
90
100
100
78
90
10
10
11
10
10
0
0
10
100
100
100
100
100
100
100
100
MDL
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.4
0.08
0.28
0.24
0.8
0.2
0.001
0.001
0.05
0.05
0.001
0.001
0.02
0.02
0.02
0.01
0.25
0.25
0.07
0.04
2.5
2.5
0.001
0.001
0.02
0.02
0.001
0.001
0.02
0.02
Mean
0.12
0.1
0.27
0.2
0.28
0.2
0.05
0.09
0.58
0.62
0.38
8.6
10.8
2.3
NC
NC
NC
NC
23.6
0.026
0.016
0.18
0.28
0.017
0.052
0.099
0.50
NC
NC
NC
NC
NC
NC
NC
NC
0.19
0.96
2.0
6.2
0.18
0.96
2.6
10
SD
0.18
0.09
0.21
0.41
0.23
0.18
0.05
0.13
0.37
0.4
0.27
14
13
1.3
NC
NC
NC
NC
59
0.025
0.008
0.10
0.18
0.012
0.13
0.094
1.1
NC
NC
NC
NC
NC
NC
NC
NC
0.11
2.4
2.8
13
0.35
2.6
2.4
22
P50
0.06
0.07
0.22
0.1
0.18
0.12
0.03
0.05
0.7
0.7
0.45
3.5
7.6
2.2
0.08
O.28
O.24
<0.8
1.44
0.019
0.015
0.17
0.24
0.014
0.009
0.070
0.13
0.02
0.01
0.25
O.25
O.07
O.04
<2.5
<2.5
0.18
0.16
1.1
1.8
0.088
0.059
1.9
2.0
P95
0.42
0.23
0.75
0.46
0.73
0.52
0.12
0.16
1.0
1.2
0.8
53
30
5.1
1.8
2.6
O.24
128
180
0.095
0.025
0.37
0.64
0.043
0.42
0.29
3.5
0.038
0.047
1.9
2.3
1.1
O.04
<2.5
14
0.41
7.9
8.7
43
1.2
8.4
7.7
71
NC, Not calculated
125
-------
Table 7.11 Results of multiple linear regression modeling of measured bodysuit pesticide loading
(ng/cm2/sec) from data collected in the daycare study.
Effect
Intercept
Bodysuit Section
Visit
Session
Activity Level
Classroom
Level
intercept
arms
legs
lower torso
upper torso
first
second
third
am
pm
high
middle
low
infant
preschool
Estimate
-1.43
0.46
1.05
1.35
0
0.87
0.31
0
0.44
0
1.36
0.65
0
0.38
0
p-Value
0.0001
0.0001
0.0006
0.0006
O.0001
0.0386
Table 7.12 Estimates of between- and within-person variability for loading on individual
bodysuit sections.
Statistic
Between-person variance (logged)
Within-person variance (logged)
Intraclass Correlation Coefficient
GSD, between
GSD, within
Arms
0.26
0.76
0.25
1.7
2.4
Upper
0.04
0.76
0.05
1.2
2.4
Legs
0.67
1.02
0.40
2.3
2.7
Lower
0.37
0.59
0.39
1.8
2.2
126
-------
ARMS
UPPER TORSO
CM
E
10 -
1 -
0.1
0.01 -
T
T
r
1
18 Jul 2001 |22 Auq 2001 I 19 Sep 2001
am pm am pm am pm
10
1
0.1 -
0 01 "
-p
I I [==]
I I ' r-
1 ' I
I -L F^
I ~"~ -1-
1
18 Jul 2001 22 Auq 2001 19 Sep 2001
pm
pm
pm
LEGS
LOWER TORSO
10 -
x x
CM
! "
571
c
1 0.1 -
0.01 -
i
^ -T T
I
I
-1 ,-U
Ep
n^
J_ _L
18 Jul 2001 22 Auq 2001
am pm am pm
^
19
=1 T
Sep 2001
am pm
10 -
"cs"
0.1
0.01 -
T
T
18 Jul 2001
22 Auq 2001 19 Sep 2001
pm
pm
pm
Figure 7.10 Bodysuit section loadings (ng/cm2) by monitoring period from the Day care study.
127
-------
- 19D
e120-
O
~ 90
&
a
re
c 60 -f
re
CO
d> oj oj
o ฐ- o ฐ-
1 ID I ID
am pm am
Visit No. 1 Vi
D Infants
n_ Preschool
_
r r
p
r
1 f 1 1 1 f 1 1 1
d) d) d) d)
o ฐ- o ฐ-
1 ID 1 ID
pm am
=rs
[
o
0) W
jj ฐ
o
1
0 (/
(/) r
O >-
1- <
(D
Q.
Q.
pm
sit No. 2 Visit No. 3
)
Figure 7.11 Relative standard deviations of esfenvalerate loadings on cotton garment sections
among infants and preschoolers in the Daycare study.
0.12
0.00
1234567
9 10 11 12 13 14 15 16
Rank (Highest=1)
Figure 7.12 Handwipe loadings (ng/cm2) above method detection limit among infants and
preschoolers in the Daycare study. Values are sorted in descending order, illustrating that the
highest loadings were typically from infants and the lowest typically from preschoolers.
128
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8.0 URINARY BIOMARKER MEASUREMENTS
Biological markers are indicators of the actual body burden of a chemical. As such, they reflect
all routes of exposure, as well as inter-individual differences in absorption and metabolism.
Moreover, they are often more directly related to potential adverse health effects than the
external concentrations (Lowry, 1986: Hulka and Margolin, 1992). In human observational
measurement studies involving young children, urine is the primary vehicle for biomonitoring.
Urine is advantageous over blood because of its noninvasiveness, ease of collection, and large
available quantity. Urinary biomarkers, however, also have disadvantages related to
uncertainties in the fraction of the absorbed compound that is eliminated and in the precision of
the measurements.
The relationship between a biological marker and external exposure is influenced by factors
related both to the environment and to human physiology. Factors related to the environment
include spatial and temporal variability in exposure concentrations (as discussed in earlier
chapters of this report) and effects of the presence of other chemicals (Coble et al, 2005).
Factors related to human physiology include differences, both over time and across individuals,
in the rates of absorption, distribution, metabolism, and excretion (Droz, 1989). When biological
monitoring and exposure monitoring are used together, the relationship between the two may be
evaluated to investigate the relative contribution of the various exposure routes.
Evaluating the relative contribution of exposure routes to aggregate intake is subject to error
related to estimates of exposure and of aggregate intake. Issues related to route-specific
exposure estimates have been discussed earlier. Dependable information on the toxicokinetics
(absorption, distribution, metabolism, and excretion) of a compound are necessary for reliable
estimates of aggregate intake, whether those estimates are derived from the sum of route-specific
absorption estimates or from excreted biomarker levels. To accurately estimate aggregate intake
from excreted biomarker levels, urinary biomarker output rates must be calculated from the
biomarker levels. Such calculations require information on the entire urine volume and elapsed
time since previous void - information that has rarely been collected in field studies.
8.1 Toxicokinetics of Organophosphate and Pyrethroid Pesticides
Some understanding of organophosphate and pyrethroid pesticide toxicokinetics is necessary to
meaningfully compare the environmental and dietary concentrations presented in the previous
chapters with the urinary biomarker concentrations presented in this chapter. Despite extensive
usage, remarkably little is available from the scientific literature on kinetic parameters in
humans. Parameters reported for absorption of parent compounds and elimination of urinary
metabolites following pesticide exposure are summarized in Table 8.1.
Absorption
Inhalation studies with a variety of gases have shown that even the most efficiently absorbed low
molecular weight, highly water soluble compounds rarely exceed 70% uptake. No studies
reporting the fraction of organophosphate pesticides absorbed through inhalation were found, but
129
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Leng etal. (1997) reported that only about 16% of the pyrethroid cyfluthrin was absorbed
through inhalation.
The importance of the dietary contribution to aggregate exposure among infants and young
children is well known (NRC, 1993), but few studies have investigated what fraction of ingested
pesticide residue is absorbed. For organophosphates, Nolan etal. (1984) estimated 70%
absorption of chlorpyrifos based on urinary 3,5,6-trichloro-2-pyridinol (TCPy), whereas others
estimated 60% to 93% absorption based on dialkylphosphate (DAP) metabolites (Garfitt etal.,
2002; Griffin etal., 1999). Diet reportedly affects absorption (Timchalk etal., 2002). As for
pyrethroids, Woollen etal. (1992) estimated that 27-57% of cypermethrin was absorbed, while
Eadsforth and colleagues (1983; 1988) estimated 45-49% and 72-78% for the cis and trans
isomers, respectively.
Dermal absorption is typically low due to loss by washing, evaporation, or exfoliation (Feldmann
and Maibach, 1974). For organophosphate pesticides, absorption of chlorpyrifos was estimated,
based on its primary metabolite TCPy, to be 1.28% of an applied dose of 4 mg/cm2 (over 12-20
hr) (Nolan et al, 1984), and 1.2% and 4.3% of applied doses of 0.15 and 0.05 mg/cm2 (over 4
hr), respectively (Meuling et al., 2005). Absorption of both chlorpyrifos and diazinon was
estimated to be about 1% of applied doses of about 0.4 and 1.3 mg/cm2 (over 8 hr), respectively,
based on DAP metabolites (Griffin et al, 1999; Garfitt et al, 2002). The percent that is
absorbed increases as the applied dose (per cm2) decreases. Large differences have been
reported by anatomical area (Maibach et al, 1971) and among individuals (Feldmann and
Maibach, 1974). For pyrethroids, Bartelt and Hubbell (1987) found only about 2% of applied
permethrin to be absorbed within 24 h. Wester et al (1994) observed that approximately 2%
(forearm) and 7.5% (scalp) of radiolabeled pyrethrin was absorbed. The ATSDR (2001) has
concluded that for pyrethroids in general, < 2% of the applied dermal dose is absorbed, at a rate
much slower than that by the oral or inhaled routes.
Due to the paucity of available information on absorption from human studies, simple default
values based on human studies, animal studies, and conservative assumptions are often required.
For small children (ages 1-6) the following route-specific absorption is often assumed: 50-100%
for inhalation, 50% for ingestion, and 1-3% for dermal. In addition, a daily intake of 100 mg of
house dust is assumed for indirect ingestion. These absorption assumptions are a source of
substantial uncertainty in route-specific intake estimates. In fact, since dermal absorption
increases with decreasing dermal loadings (as demonstrated above with organophosphates),
default assumptions of less than 3% for dermal absorption may underestimate absorption at the
very low levels measured in field studies
Distribution and Metabolism
Once in the bloodstream, organophosphate or pyrethroid pesticides are rapidly distributed and
metabolized. A typical organophosphate (OP) pesticide is composed of a dialkyl (either
dimethyl or diethyl) phosphate moiety and an organic group. Hydrolytic cleavage of the ester
bond yields one dialkylphosphate (DAP) metabolite and one organic group moiety (Barr etal,
2004). Dimethyl OPs (including malathion, phosmet, and azinphos-methyl) produce dimethyl
metabolites and diethyl OPs (including chlorpyrifos and diazinon) produce diethyl metabolites
130
-------
(Aprea etal, 2002). The organic group metabolites, including 2-isopropyl-6-methyl-4-
pyrimidinol (IMPy) for diazinon and 3,5,6-trichloro-2-pyridinol (TCPy) for chlorpyrifos, are
considered to be semi-specific.
Pyrethroids are esters of chrysanthemic acid and benzyl alcohols. Hydrolytic cleavage of the
ester bond yields a benzoic acid and a chrysanthemic acid derivative. The 3-phenoxybenzoic
acid (3-PBA) metabolite is common to 10 of the 18 pyrethroids registered in the United States
including permethrin, cypermethrin, deltamethrin, esfenvalerate (Baker etal., 2004). Other
benzoic acid metabolites analogous to 3-PBA are more specific and include 4-fluoro-3-
phenoxybenzoic acid (4F3PBA) from cyfluthrin and 2-methyl-3-phenylbenzoic acid (MPA)
from bifenthrin. These are not necessarily terminal metabolites; for example, as much as 38% of
3-PBA has been reported by Woollen et al. (1992) to undergo further oxidation to 3-(4'-
hydroxyphenoxy) benzoic acid (4OH3PBA). The chrysanthemic acid derivative cis-2,2-
dibromovinyl-2,2-dimethyl-cyclopropane-l-carboxylic acid (DBCA) is specific to deltamethrin
while the cis- and trans- isomers of 2,2-dichlorovinyl-2,2-dimethyl- cyclopropane-1-carboxylic
acid (DCCA) are common to permethrin, cypermethrin, and cyfluthrin.
Excretion
Both the OPs and the pyrethroids are rapidly eliminated in urine. Elimination appears to follow
first-order kinetics, with elimination half-times in humans ranging from 2 to 41 hours for OPs
and from 6.4 to 16.5 hours for pyrethroids, depending on both the compound and the route of
exposure (ATSDR, 2001; Garfitt et al., 2002; Meuling et al., 2005). The elimination half-life of
about 8 hours reported for 3-PBA among workers exposed to cypermethrin (Kuhn etal., 1999)
suggests that 88% of the metabolite is excreted within the first 24 hours following exposure.
Route-specific differences in the peak excretion of urinary OP pesticide metabolites have been
reported (Griffin et al., 1999; Garfitt et al., 2002; Meuling et al., 2005). Peak excretion is
observed to occur 6 to 24 hours later when absorption is by the dermal route compared to when
absorption is by the oral route, largely because of route-specific differences in absorption. Peak
excretion may occur as late as 48 hours following dermal exposure, as observed among
volunteers performing scripted "Jazzercise" activities (Krieger etal., 2000). Extended peak
excretion times suggest that chlorpyrifos may be retained by the skin and may remain
systemically available for prolonged periods (Meuling et al., 2005)
While the above toxicokinetic studies evaluate excreted mass or mass rates, our past field studies
have largely evaluated only biomarker concentrations. In the future, all studies should include
information on void volumes and times to allow excreted mass to be calculated. Relevant
transformations can be found in Rigas et al. (2001) and are currently incorporated in the SHEDS
model.
131
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Table 8.1 Absorption and elimination characteristics for pesticides and urinary biomarkers of pesticide exposure.
COMPOUND
Chlorpyrifos
Diazinon
Pyrethroids
(as a group)
Permethrin
Cyfluthrin
Cypermethrin
ABSORPTION OF PARENT COMPOUND
ORAL
Volunteer studies: 70% of oral
dose excreted in urine as
TCPy (Nolan ef a/., 1984),
93% of oral dose excreted in
urine as dialkyl-phosphates
(Griffin et al, 1999).
Absorption factor estimated at
0.90 (ATSDR).
Human oral absorption
approx. 60% (Garfitt et al,
2002). Default oral absorption
factor of 0.85 (ATSDR).
Absorption is incomplete,
minimum estimate 40 - 60%,
but first- pass metabolism may
underestimate absorption
(ATSDR, 2001).
Oral absorption factor of 0.70
suggested (NRC).
No Information.
Human volunteer study 27-
57% (mean 36%)
cypermethrin absorbed
(Woollen et al, 1992).
DERMAL
Volunteer studies: 1.3% of
dermal dose excreted in urine
as TCPy (Nolan et al, 1984).
1% of dermal dose excreted as
dialkyl-phosphates (Griffin et
al, 1999), 1.2 - 4.3% of
dermal dose excreted as TCPy
(Meulingefa/., 2005).
Human dermal absorption rate:
456 ng/cmVh (Garfitt et al,
2002).
<2% of the applied dermal
dose is absorbed, rate of
absorption much slower than
by the oral or inhaled routes;
may be stored in skin and then
slowly released into the
systemic circulation (ATSDR,
2001).
Poor dermal absorption: 2%
of applied dose absorbed/24 h
(Bartelt and Hubbell, 1987);
7.5% (scalp) and 1.9%
(forearm) of applied dose
(Wester et al, 1994).
No Information.
No Information.
INHALATION
No Information.
No Information.
Rapidly absorbed in
humans following
inhalation, but no
estimates of fraction
absorbed are available
(ATSDR, 2001).
No Information.
Human data suggest
15% absorption
(Leng et al, 1997).
No Information.
ELIMINATION OF METABOLITES
ORAL
Volunteer study, 27 h oral
(Nolan et al, 1984).
Volunteer study, approx
15. 5 h oral (Griffin et al,
1999).
Human study, 2 h oral
(Garfitt et al, 2002).
DERMAL
Volunteer study, 27 h
dermal (Nolan et al,
1984). Volunteer study,
approx 30 h dermal
(Griffin et al, 1999).
Volunteer study, approx 41
h dermal (Meuling et al,
2005).
Human study, 9 h dermal
(Garfitt et al, 2002).
INHALATION
No Information.
No Information.
Elimination appears to follow first-order kinetics, with elimination half-times in
humans ranging from 6.4 to 16.5 hours, depending upon the specific pyrethroid and
exposure route studied (ATSDR, 2001).
No Information.
Human oral dosing
produced t-'/2 of 6.4 h
(Leng et al, 1997b).
Human oral dosing,
urinary metabolites have
mean '/z-life of 16.5 h
(Woollen et al, 1992).
No Information.
No Information.
Human dermal dosing,
excretion rates peaked at
12-36 h, mean '/z-life was
13 h (Woollen et al,
1992).
No Information.
Human H-lives of 6.9 h (c-
DCCA), 6.2 h (t-DCCA),
5.3 h(FPBA) (Leng etal,
1997).
No Information.
132
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8.2 Measurements of Pesticide Metabolites in Urine
Urinary biomarkers were measured in several large-scale and pilot-scale children's observational
measurement studies described in Table 8.2. These include the MNCPES, CTEPP, NHEXAS-
AZ, CPPAES, JAX, CHAMACOS, PET, and DIYC studies. All urine samples were collected
exclusively at the children's homes except for the CTEPP study, in which urine samples were
also collected at daycare centers. Urine collection followed outdoor turf applications in the PET
study and routine professional indoor applications in the DIYC and CPPAES studies.
Spot urine samples, mainly first morning voids, were collected using age-appropriate methods
including under-toilet seat bonnets (CTEPP, PET), collection cup (NHEXAS-AZ, MNCPES),
diaper insert (DIYC), and "potty chair" (CPPAES). Table 8.3 presents selected organophosphate
(OP) and pyrethroid metabolites that were measured in the children's urine samples in multiple
studies. The pesticide metabolites are 3,5,6-trichloro-2-pyridinol (TCPy), 2-isopropyl-6-methyl-
4-pyrimidinol (IMP), and 3-phenoxybenzoic acid (3-PBA).
Sample collection was performed by the children's caregivers following protocols provided by
the investigators. Chemical analysis of urinary metabolites in nearly all included studies was
performed by the National Center for Environmental Health of the Centers for Disease Control
and Prevention in Atlanta, GA, using validated tandem mass spectroscopy techniques (Baker et
al, 2000; Baker et al, 2004; Beeson etal, 1999; Hill etal, 1995). Chemical analysis for the
CTEPP study was performed by Battelle Institute using validated gas chromatography/mass
spectroscopy techniques.
Limits of detection for each pesticide metabolite are given by study in Table 8.4. Detection
frequencies are provided in Figure 8.1. Concentrations for the median and 95th percentiles for
each urinary metabolite are presented by study in Table 8.5. Figure 8.2 shows the log probability
plots of urinary TCPy and 3-PBA concentrations for children across large observational field
studies. Figure 8.3 presents the box-and-whisker plots that graphically depict the urinary TCPy
and 3-PBA concentrations for both the large-scale and pilot-scale children's observational
measurement studies.
The National Health and Nutrition Examination Survey (NHANES) includes an ongoing
assessment of the exposure of the U.S. population to environmental chemicals through the
measurement of biomarkers. Spot measurements of urinary pesticide biomarkers among children
6 to 12 years old from both the 1999-2000 and the 2001-2002 cycles are included for comparison
with results from our studies. Please note that NHANES does not report results by region or by
season.
The chlorpyrifos metabolite TCPy was detected in over 90% of the children's urine
samples in all listed studies. The pyrethroid metabolite 3-PBA was detected in over 60%
of the CTEPP-OH samples and over 90% of the JAX samples (Figure 8.1).
The urinary TCPy concentrations were at least an order of magnitude higher than the
urinary 3-PBA concentrations across studies (Figure 8.2).
133
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There is virtually no difference in urinary TCPy concentrations measured in CTEPP NC
and OH, but the concentrations from Minnesota and Arizona are substantially higher
(Figure 8.2, all unweighted). Higher levels in MNCPES and NHEXAS-AZ may reflect
intentional oversampling of pesticide-using households in MNCPES, and greater use of
chlorpyrifos at the time that MNCPES and NHEXAS-AZ were conducted.
Compared to values for children under 12 years old collected in the 1999-2002 NHANES
(Figure 8.2), the median TCPy values were higher in all of our studies, but the 95th
percentile values were only higher for MNCPES.
The children in JAX had levels of 3-PBA that were at least seven times higher than those
of children in CTEPP-OH (Figure 8.3). All urine data from JAX participants suggest that
JAX is a high pesticide usage area.
The median 3-PBA value in CTEPP (0.3 ng/mL) was similar to NHANES (0.3 ng/mL),
but the median JAX value (2.2 ng/mL) was much higher (Figure 8.3).
Levels of IMP were about an order of magnitude higher in DIYC compared to PET or
NHANES (Figure 8.3).
The median urinary TCPy concentration was the highest for the NHEXAS-AZ and JAX
studies and the lowest for the CTEPP-NC and CTEPP-OH studies (Table 8.5).
In the CPPAES study, the intensity of the crack and crevice applications of chlorpyrifos
was described as either high (n = 7) or low (n = 3), with mean air concentrations resulting
from "high" applications five orders of magnitude higher than those from "low"
applications. Figure 8.4 shows that the urinary TCPy concentrations over time were not
much different for the children in the high versus low application groups.
For children in the "high" application group in CPPAES, the median urinary TCPy
concentration one day before application of chlorpyrifos was higher than on the first two
days following application (Figure 8.4). Crack and crevice applications of chlorpyrifos at
these homes did not substantially increase the children's urinary TCPy concentrations.
The concentration-time profiles for urinary TCPy levels in CPPAES did not mirror the
environmental concentration time profiles (Figure 8.5).
134
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Table 8.2 Summary of the children's urinary biomarker collection methods.
Study
NHEXAS-AZ
(subset)
MNCPES
CTEPP
JAX
CHAMACOS
CPPAES
PET Pilot
DIYC
N
21
102
257
9
20
10
6
3
Age
Range
5 to!2 yr
3 to 13 yr
2 to 5 yr
4 to 6 yr
6 to 24 mo
2 to 4 yr
5 to 12 yr
1 to 3 yr
Sampling Device
Urine collection
cup
Urine collection
cup
Bonnet for
children, urine
collection cup for
adults
Plastic cup
Cotton diaper and
Infant urine
collection bag or
commode
container
Toys R' Us
child's potty,
plastic cup
Urine collection
bottle or urine
bonnet
Diaper insert or
collection cups
Collection
Strategy
Morning void
Morning void
Morning void,
after lunch, after
dinner/ before
bedtime
Morning void
One overnight
and one spot
sample
Morning void
Morning void
Morning void and
other spot
samples
Collection
After Pesticide
Use
No
No
Only for some
homes (-15%)
Yes, indoor
No
Yes, indoor
Yes, outdoor
Yes, indoor
Collection Frequency
Once (in 3 -day
monitoring period)
Days 3, 5, and? of
sampling period
Over a 48-hr period
1 day
Once
Pre- and days 1,2,3,5,
7,9, and 11 post-
application
Pre- and days 1,2,4,
and 8 post-application
Days 3, 5, and 7 post-
application
Analytes a
TCPy
TCPy
TCPy, 3-PBA
(Ohio, only)
TCPy, IMP,
3-PBA
Dialkyl
Phosphate
metabolites
TCPy
IMP
IMP
Urinary Output
Correction
Factors
Creatinine
Creatinine
Creatinine,
Specific gravity
Creatinine
Creatinine
Creatinine
Creatinine
Creatinine
1 Analytes relevant to interstudy comparison. Most studies included additional metabolites.
135
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Table 8.3 Urinary metabolites of organophosphate and pyrethroid pesticides measured in the
children's observational measurement studies.
Metabolite
3,5,6-Trichloro-2-pyridinol (TCPy)
2-Isopropyl-6-methyl-4-pyrimidinol (IMP)
3-Phenoxybenzoic acid (3-PBA)
Parent Compound
Chlorpyrifos a
Diazinon
Permethrin b
a TCPy is also a metabolite of chlorpyrifos-methyl, which may occur in children's diet.
b Several other pyrethroids are metabolized into 3-PBA including cypermethrin, deltamethrin, fenvalerate,
fluvalinate, permethrin, sumithrin.
Table 8.4 Limits of detection (ng/mL) for each pesticide metabolite measured in the children's
urine samples by study.
Study
NHEXAS-AZ
MNCPES
CTEPP-NC
CTEPP-OH
JAX
CPPAES
PET
DIYC
TCPy
1.0
1.4
1.0
1.0
0.4
1.0
NA
NA
IMP
NA
NA
NA
NA
2.0
NA
0.3
1.0
3-PBA
NA
NA
NA
0.2
0.5
NA
NA
NA
NA, Not Applicable.
Table 8.5 Median and 95th percentile values (ng/mL) for the pesticide metabolites TCPy, IMP,
and 3-PBA measured in the children's urine samples by study.
Study
NHEXAS-AZ
MNCPES
CTEPP-NC
CTEPP-OH
JAX
CPPAES
PET
DIYC
TCPy
P50
12.0
7.2
5.3
5.1
9.8
7.7
NA
NA
P95
26.0
23.0
15.5
12.3
21.2
18.0
NA
NA
IMP
P50
NA
NA
NA
NA
-------
Detection Frequency in Urine
100
90-
~ 80-
^
^ 70-
ฎ 60H
ฃ 50H
o 40H
30H
-------
TCPY
URINE (ng/ml)
3-PBA
URINE (ng/ml)
100
100 -
.1.2.51 2 5 10 203040 6070 80 9O 95 99 99.9
Percent
+ + + NHEXAS-AZ XXX MNCPES
Y Y Y CTEPP-NC Z Z Z CTEPP-OH
0 0 O NHANES
.1.2.51 2 5 10 203040 607080 9095 99 99.!
Percent
z z z CTEPP-OH a a e> NHANES
100 i
1
.01 H
IMP
URINE (ng/ml)
.1.2.51 2 5 10 203040 607080 GO 95 99 9S.S
Percent
ฉ 0 ฉ NHANES
Figure 8.2 Log probability plots of urinary TCPy, 3-PBA, and IMP concentrations across large
observational field studies. NHANES results are included for comparison.
138
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TCPY
URINE (rig/ml)
3-PBA
URINE (ng/mf
en
c
o
fee
o
o
10
0.1
0.01 -
IDDD-i
100i
1D-
1 -
0.1 -
0.01 -
I
\ i i i i r
UN CTEPP-NC CTEPP-QH JAX-EXPO CPPAES NHANES
I I I I
CTEPP-OH JAX-SCR JAX-EXPO NHANES
IMP
URINE (ng/ml)
O
O
1000-
100-
10-
1 -
0.1 -
0.01 -
CTEPP-OH PET
DIYC
Figure 8.3 Box-and-whisker plots comparing the urinary TCPy and 3-PBA concentrations across
studies.
139
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2O-
16-
16-
14-
12-
8-
6-
4-
2-
O-
r
Fi
_
I
C
- L
L
^
s
c
20-
18-
16-
14-
r*~i "dr
^E 12"
vS 10'
Si S-
II
0:
_
p
'
j I
,_
-
-
2 3 5 7 9 11
-11 236
Figure 8.4 Urinary TCPy concentrations (ng/mL) over time for the children in the high and low
application groups in CPPAES.
CPPAES - Chlorpyrifos in Air
CPPAES -Chlorpyrifos on Surfaces
CPPAES-TCPy in Urine
300
f250
I 200
o
*5 150
ง 100
c
o
0 50
0
'
/
/
8
-"-Air 1
\
\
I
/
1 ~I
1
"a 5
c^
oi 4-
_ c
-\ T "s 3'
^^-i_ T T S
I~~~^J 1 J t
~~$ 9 2'
/ ^ "*" "*" 1'
i 1 1 1 1 1 1 n
/
/
15
*LWW j 12
"a
\ T f 9
\ T ฐ
T\l '^
/ iNj - ฐ
/ ^ 5~--~jc ฐ
....... n
-TCP,
J T
I_ 1^^ ~\/\~~~ ^-~~^_ T __-i~~_ 1
1 l^^l 1 ^~~~^~~t^"~~"~l~~~~~~~~~ซ
1 L
-1 1 3 5 7 9 11
Day
-1 1 3 5 7 9 11
Day
-1 1 3 5 7 9 11
Day
Figure 8.5 Time profiles for Chlorpyrifos in environmental media and TCPy concentrations in
urine for all children in the CPPAES.
140
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8.3 Temporal Variability in Biomarker Measurements
In the CTEPP study, the children's spot urine samples (up to six per child) were analyzed
separately for pesticide metabolites if the participants reported that a pesticide had been used in
their homes within seven days of field monitoring. Figure 8.6 shows the variability of urinary
TCPy concentrations in the children's urine samples over a 48-h period.
Intraclass correlation coefficients (ICCs) for urinary TCPy and 3-PBA concentrations in NC and
OH children in the CTEPP study are provided in Table 8.6. The between and within-person
geometric standard deviations (GSDs) for logged urinary concentrations of TCPy and 3-PBA for
the NC and OH children in the CTEPP study are given in Table 8.7. Concentration-time profiles
for TCPy and 3-PBA among CTEPP children are provided in Figure 8.6 and for IMP among
PET study children in Figure 8.7.
Relatively low ICCs (Table 8.6) indicate that a single measurement may not adequately
represent the mean of the 48-hr sampling period for 3-PBA among adults and TCPy
among children. Consistency of urinary metabolite concentrations over even short
periods of time appears to be dependent on both the metabolite and the study population.
Within-person GSDs are equal to or nearly equal to between-person GSDs for both TCPy
and 3-PBA in urine measured in CTEPP (Table 8.7). This indicates that a single spot
urine measurement is not sufficient to differentiate among children over a 48-hr time
frame.
Spot urine measurements over 48 hours among CTEPP participants reporting recent
pesticide applications show large sample-to-sample variability and large differences
among individuals (Figure 8.6).
Adjustment of urinary metabolite values by specific gravity did not meaningfully reduce
within-person variability of TCPy (Figure 8.6).
While no statistically significant difference was observed between pre- and post-
application urinary IMP concentrations in the PET study, the time-concentration profile
clearly shows an observable decay in children's urinary biomarker concentrations in the
eight days following the outdoor lawn application (Figure 8.7). The pattern among adults
is not consistent with that among children.
Comparing first morning voids (FMV) to other spot samples collected among a
subsample of CTEPP children (data not presented), the median concentration in FMV is
substantially (43%) higher than the median of the non-FMV samples for TCPy, and
slightly (35%) higher for 3-PBA, due to longer urine accumulation time in the bladder.
In CHAMACOS, concentrations in overnight diapers were compared to concentrations in
spot samples (Bradman et a/., 2006; data not presented). In all cases, diethyl phosphates
were lower in overnight diaper samples than in spot samples, while for toddlers dimethyl
phosphates were higher in overnight diaper samples. Median total DAP concentrations
for all children were higher in the overnight samples compared to the spot samples (140
vs. 100 nmol/1), but the differences were not statistically significant (Wilcoxon test).
141
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Spearman correlations were calculated for CHAMACOS spot and overnight samples by
age (Bradman et al., 2006). Spot and overnight urine concentrations were significantly
correlated in CHAMACOS (Bradman et a/., 2006): dimethyl phosphate (Spearman
rho=0.53; p=0.02), diethyl phosphate (Spearman rho=0.48; p=0.03), and total DAP
metabolites (Spearman rho=0.57; p=0.009).
Table 8.6 Intraclass correlation coefficients (ICC) for logged CTEPP urinary metabolites. a
Metabolite
3-PBA
TCPy
NC Children
b
0.65
OH Children
0.70
0.48
a An ICC of 0.80 indicates that a single measurement reliably represents the average of a set of measurements.
b - = no data.
Table 8.7 Between- and within-person geometric standard deviations (GSDs) for logged urinary
concentrations from children in the CTEPP study.
Metabolite
3-PBA
TCPy
Measure
Between-person GSD
Within-person GSD
Between-person GSD
Within-person GSD
NC Children
a
-
1.5
1.3
OH Children
1.5
1.2
1.5
1.5
a - = no data.
142
-------
12:00 24:00 36:00 48:00 60:00
Time (Hours)
B
12:00 24:00
36:00 48:00
Time (Hours)
60:00 72:00
i
6
3
1
12:00 24:00
36:00 48:00
Time (Hours)
60:00 72:00
12:00 24:00 36:00 48:00 60:00
Time (Hours)
Figure 8.6 Concentration versus time plots for urinary TCPy measurements among CTEPP-NC
and CTEPP-OH participants reporting a recent pesticide application. Urines in panels A and B
are without adjustment. Urines in panels C and D are adjusted by specific gravity. Note that not
all voids within the 48 hour period were collected.
Children's IMP (mean +/- std err)
3.5
3.0
J2.5
0)2.0
oTl.5
S
~ 1.0
0.5
0.0
4
Day
Adults' IMP (mean +/-std err)
-2
4
Day
Figure 8.7 Time-concentration profile for urinary IMP measurements among child and adult PET
study participants following an outdoor granular turf pesticide application.
143
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8.4 Urine and Creatinine Excretion among Children
Urine output varies with water intake, urea, salt, specific gravity, and osmolality (Wessels et al,
2003). Consequently, the concentration of metabolites in spot urine samples may vary, even if
the internal dose remains constant. Since collecting 24-h urine samples from children is often
impractical, spot urine samples are commonly collected and normalized using creatinine (CRE)
concentration. However, CRE yield has been shown to be variable among children (Freeman et
al., 1995; O'Rourke et al., 2000). Furthermore, because CRE excretion is dependent upon
muscle mass, children inherently excrete less CRE than adults. This makes comparisons
between CRE-adjusted adult and children urinary biomarker concentrations subject to error due
to "over-correction" of children's samples. Age-dependent differences in daily creatinine
clearance must also be considered when comparing young children and older ones (Krieger et
al., 2001; Wessels et al, 2003), as differences are great even for 1-year olds (0.08 g
creatinine/day) relative to 5-year olds (0.4 g creatinine/day).
Alternative approaches for adjusting for urine dilution are based on urinary specific gravity and
on urinary output. Specific gravity adjustment accounts for all dissolved solids, with a specific
gravity of 1.024 considered normal for adults. Both specific gravity and creatinine were
measured in CTEPP urine samples.
Urinary output among young children is often estimated with equations from the Exposure
Factors Handbook. Zartarian et al (2000) estimated daily urinary output volumes of 500 and 800
mL for the children 0-4 and 5-9 years of age, respectively, based on Geigy Scientific Tables.
Estimated daily urinary output and creatinine excretion for children 3-12 years of age based on
first morning void measurements and recorded ancillary information from the MNCPES are
presented in Figure 8.8.
In unpooled samples from CTEPP, specific gravity of children's urine averaged 1.020,
significantly different than the 1.024 of adult urine (t-test, p < 0.001).
In the MNCPES study, the daily urine output rates (mean ฑ SD) increased from 13 ฑ 6
mL/hr for 3-4 year olds to 19 ฑ 7 mL/hr for 11-12 year olds (Figure 8.8) based on first
morning void samples with known volumes and void times.
In the MNCPES study, creatinine excretion rates (mean ฑ SD) increased from 10 ฑ 4
mg/hr for 3-4 year olds up to 24 ฑ 12 mg/hr for 11-12 year olds (Figure 8.8).
There was neither a substantial nor consistent difference between sexes for either daily
urine output or daily creatinine excretion rate, suggesting that sex is not an important
predictor of creatinine excretion for pre-pubescent children (Figure 8.8).
Failure to appropriately account for creatinine excretion results in "over-correction" of
children's samples when making comparisons between CRE-adjusted adult and children
urinary metabolite concentrations, making child levels appear higher by comparison.
An alternate approach for avoiding issues with variable urine volumes is to calculate
biomarker excretion rates. This requires collection of complete voids, void volume
measurements, and recording previous and final void times.
144
-------
Overnight Urine Output (mL)
5-6 7-8 9-10
Age (years)
Overnight Urine Output Rate (mL/hr)
5-6 7-8 9-10
Age (years)
11-12
Estimated 24-hr Urine Output (mL)
T
I
T
T
T
i
I
i
T
1
rF
T
1
ffi
5-6 7-8 9-10 11-12
Age (years)
c
o
1
c
o
U
0)
c
-------
8.5 Relative Importance of Exposure Routes
The relative importance of the dietary ingestion, indirect ingestion, dermal, and inhalation routes
of exposure with respect to aggregate intake has been investigated with data from both the
MNCPES and CTEPP studies. Daily inhalation and dietary intake estimates (ng/kg/day) for
chlorpyrifos among children in MNCPES are available in Clayton etal. (2003). Estimated
relative importance of the inhalation, dietary ingestion, and indirect ingestion routes of exposure
to OPs and pyrethroids among children in CTEPP are presented in Morgan etal. (2004).
MNCPES chlorpyrifos data showed that ingestion was a more dominant route of intake
than inhalation. Urinary metabolite levels, however, showed a stronger association with
air (r=0.42, p<0.01) than with dietary (r=0.22, p<0.05) measurements.
Using MNCPES data as an input, the SHEDS model suggested (data not presented) that
the dominant pathway for highly exposed chlorpyrifos users was non-dietary ingestion,
followed by dietary ingestion. The model also suggested that the relative contribution of
exposure pathways may differ by pesticide.
TCPy was found in several environmental media in CTEPP, particularly in solid food
samples. Estimated intake of TCPy (Figure 8.9) was about 12 times higher than intake of
chlorpyrifos for CTEPP children. Even when environmental TCPy is considered, nearly
60% of the TCPy excreted in urine remained unaccounted for. This suggests that either a
major pathway of children's exposure to chlorpyrifos and TCPy remains unaccounted for
in our algorithms or that some underlying assumptions are incorrect.
Despite indications that intake of TCPy from solid food may be responsible for the bulk
of TCPy intake, intake from solid food and excretion are poorly correlated (r2=0.01,
Figure 8.10). The absorption rate for TCPy remains unknown, as does whether or not it
is metabolized to other products in the body.
Based on exposure algorithms (with absorption assumed to be 50% by each route), the
primary route of exposure and intake for chlorpyrifos and permethrin among CTEPP
children was dietary ingestion (Table 8.8 and Figure 8.11). Inhalation was the secondary
route for chlorpyrifos and diazinon (organophosphates); while indirect ingestion was the
secondary route for permethrin (pyrethroid).
Based on algorithms, the contribution of diet to aggregate intake generally decreases as
intake increases (Figure 8.12). Conversely, nondietary ingestion becomes increasingly
important with increasing aggregate intake.
Unlike with TCPy, the estimated aggregate intake of cis- and ^raws-perm ethrin among
CTEPP-OH children was close to the excreted amount of 3-PBA (Figure 8.12).
However, children may have also been exposed to other pyrethroids that are metabolized
into 3-PBA and could have contributed to the excreted amounts measured.
Our studies consistently report a low correlation between concentrations of urinary
biomarkers of pesticide exposure and environmental concentrations. Algorithm-based
estimates of aggregate intake do little to improve the correlation. A better understanding
of how differences in activities between children affects intake may be needed.
Figures 8.14 and 8.15 present environmental and dietary levels of chlorpyrifos and
146
-------
urinary concentrations of TCPy by study. There is little evidence that differences in
environmental media concentrations translate into differences in urinary concentrations.
The pattern is most similar between food and urine concentrations (Figure 8.15).
Table 8.8 Estimated relative importance of the inhalation, dietary ingestion, and indirect
ingestion routes of exposure among children in CTEPP NC and OH.
Class
OP Insecticide
Pyrethroid Insecticide
Pollutants
Chlorpyrifos and Diazinon
cis- and /rans-Permethrin
Apportionment of Aggregated Exposure/Dose
NC: dietary ingestion ~ inhalation > indirect ingestion
OH: dietary ingestion > inhalation > indirect ingestion
NC: dietary ingestion ~ indirect ingestion > inhalation
OH: dietary ingestion > indirect ingestion > inhalation
120i
100
80
60
40
20
0.
^
y
/
/
/
/
/
^_
s ^
\ ffi
xซHPl
/
Intake of Intake of Excreted amount
Chlorpyrifos TCP of TCP in urine
Figure 8.9 The median estimated intakes of Chlorpyrifos and TCPy in CTEPP-NC compared with
the excreted median amounts of TCPy in the preschool children's urine (Morgan etal., 2005).
147
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60
PH
5-
$ 4
.S
w
3-
0 10 10 30 40 50 GO 70 BO 90 100 110 110 130 140 150 160 170 180 190 100
Dietary intake of TCPy (ng/kg/day)
Figure 8.10 Intake of environmental TCPy through the dietary route correlated poorly (r2=0.01)
with the amount of TCPy excreted in the urine of CTEPP-NC preschool children.
CHLORPYRIFOS
PERMETHRIN
100-
10-
o. 1 -
0.1 -
0.01 -
I I I I I
AGGR DIET INHAL INDIRECT DERMAL
100-
10-
0.1 -
0.01 -
I
AGGR
F=l
I I I I
DIET INHAL INDIRECT DERMAL
Figure 8.11 Estimated distributions of aggregate intake ("AGGR") of chlorpyrifos and
permethrin (ng/kg/day) and estimated distributions of the four contributing routes (diet,
inhalation, indirect ingestion, and dermal) among CTEPP-OH children.
148
-------
Dose (cis-Permethrin)
100%
o
o
01
Q.
90% -
80% -
70% -
60% -
50% -
40%
30% -
20% -
10% -
0%
Lowest to Highest Aggregate Dose
Figure 8.12 The contributions of inhalation, dermal absorption, diet, and nondietary ingestion to
aggregate intake of c/'s-permethrin.
TCPy
3-PBA
1000'
100-
10'
D)
C
0.1
1000'
100'
a
0) 10'
Intake (NC) Excretion (NC) Intake (OH) Excretion (OH)
0.1'
Intake (OH) Excretion (OH)
Figure 8.13 Children's estimated aggregate intake of chlorpyrifos and permethrin compared to
their measured urinary metabolites (CTEPP).
149
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CHLORPYRIFOS
INDOOR AIR (ng/m3)
CHLORPYRIFOS
OUTDOOR AIR (ng/m3)
E
Z
bJ
O
Z
o
u
10000-
1000-
10Q-;
10-
1 -
0.1 -
0.01 -
E
\
en
c
Z
O
i
LJ
u
o
u
10000-;
1000
1007
10 ]
1 -
0.1
0.01 -
\ i i i i i i i r i
K m NCHM NCDC OHHM OH DC JAX CHA CPPAES TEST
I I
NCHM NCDC
OH DC JAX
CHLORPYRIFOS
DUST CONCENTRATION (ng/g)
CHLORPYRIFOS
DUST LOADING (ng/cm2)
^^
oป
\
c
z
o
tc
K
|
z
LJ
O
Z
o
o
1000000-
100000-
10000-
1000-
100-
10-
1 1
0.1 -
_,_
r-
r
h r
J h
H
_
~
~r
T
P r1!
SI I td
i
1 1
AZ NC HM NC DC OH HM OH DC CHA
IN
E
o
u>
o
z
i
10
1-i
0.1
0.01 -
0.001
i
i i i i i i
KL NC HM NC DC OH HM OH DC CHA
CHLORPYRIFOS
SOIL CONCENTRATION (ng/g)
TCPY
URINE (ng/mi;
"3
c
Z
O
1
7
CONCEI
1000000-
100000-
10000-
1000-
100-
10-
1 n
0.1 -
I
. 5 [
]
I
I
1
MN NC HM NC DC OH HM OH DC CC
E
\
c
z
o
LJ
O
O
O
1000-
100
10-
0.1-
0.01-
\ \ \ \ \ \
IM CTEPP-NC CTEPP-OK JBC-EXPO CPPAES NHANES
Figure 8.14 Distributions of TCPy in urine across studies (bottom right panel) in comparison to
distributions of chlorpyrifos in indoor air, outdoor air, dust, and soil across studies.
150
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CHLORPYRIFOS
TOTAL SURFACE LOADING (ng/cm2)
CHLORPYRIFOS
TRANSFERABLE RESIDUE LOADING (ng/cm2)
CM
E
u
en
10000
1000
100 i
10
1
0.1
0.01
0.001
0.0001 -
CM
E
u
z
D
100
10-
0.1
0.01
0.001
0.0001 -
NCHM NCHM OH HM OH HM
CHLORPYRIFOS
SOLID FOOD CONCENTRATION (ug/kg)
CHLORPYRIFOS
SOLID FOOD INTAKE (ug/day)
Z
Id
O
Z
O
O
1000 ;
100
10
1
0.1
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0.0001 -
I
~~i 1 1 1 1 r~
UN NCHM NCDC OH HM OH DC Mt
(ug/day)
u
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z
1000-
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10
1
0.1
0.01
0.001-
0.0001 -
T T I
I O P
I I
CHLORPYRIFOS
HAND LOADING (ng/cm2)
TCPY
URINE (ng/ml)
E
o
en
c
Q
<
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0.001 -
\000-:
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NCHM NCDC OHHM OH DC CPPAES CPPAES
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CTEPP-NC CIEPP-OH JAX-EXPO CPPAES NHANES
Figure 8.15 Distributions of TCPy in urine across studies (bottom right panel) in comparison to
distributions of chlorpyrifos on surfaces, in solid food, and on hands across studies.
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8.6 Model Predictions
The Stochastic Human Exposure and Dose Simulation (SHEDS) model (Zartarian etal., 2000)
provides route-specific estimates of aggregate exposures, relying on input data from assorted
data sets, including those described in this report. The Safe Foods Project is currently
developing an exposure-dose-response model to address cumulative risks associated with
exposures to multiple pyrethroids. The Project intends to use the Exposure Related Dose
Estimating Model (ERDEM) (Blancato et a/., 2004) to predict internal dose based on cumulative
exposure estimates from SHEDS. The model will be used to identify critical pathways of human
exposure and dose. A meaningful discussion of SHEDS and ERDEM is beyond the scope of this
report, but an example of an important application of SHEDS is described below.
Use of the SHEDS model with MNCPES data (Figure 8.16) helped reveal the importance
of accounting for exposures to the metabolite/degradate TCPy in environmental media.
Without such accounting, the model under-predicted urinary TCPy concentrations.
SHEDS found that urinary biomarker concentrations depend mainly on dietary intake.
An uncertainty analysis (independent of dietary) found other important factors to be:
applied pesticide mass; surface area of treated rooms; time in treated rooms; air and
residue decay rates; surface-to-skin transfer efficiency; dermal transfer coefficient; saliva
removal efficiency; fraction hands mouthed; daily hand wash events; removal efficiency;
maximum dermal loading; dermal absorption rate; and frequency of hand-mouth activity.
By identifying critical pathways of human exposure and dose (and their associated
uncertainties), models such as SHEDS and ERDEM guide the planning for future
measurement studies so that newly identified data gaps may be filled with real-world
measurement data.
Applying SHEDS to different pesticide classes will provide information on degree to
which factors that affect exposure differ across pesticide classes (e.g., pyrethroids vs.
organophosphates).
c
o
01
o
o
o
- - 'Modeled Observed
Figure 8.16 Comparison of TCPy in urine between SHEDS model and observed MNCPES data
when TCPy in the environment is not considered (Source: Xue et al, 2004).
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9.0 SUMMARY AND CONCLUSIONS
In an effort to facilitate risk assessments that take into account unique childhood vulnerabilities
to environmental toxicants, the National Exposure Research Laboratory (NERL) in the U.S.
Environmental Protection Agency's (U.S. EPA) Office of Research and Development (ORD)
identified four priority research areas as representing critical data gaps in our understanding of
environmental risks to children. These priority research areas are: 1) pesticide use patterns;
2) spatial and temporal distributions of residues in residential dwellings; 3) dermal absorption
and indirect (non-dietary) ingestion; and 4) dietary ingestion. Several targeted studies were
conducted or financially supported by NERL to specifically address these priority research
needs. The studies were designed to address the largest uncertainties associated with children's
exposure and aimed to produce sufficient real-world data to eliminate excessive reliance on
default assumptions when assessing exposure. Significant progress has been made in each of the
four priority areas leading to a more comprehensive understanding of the exposures resulting
from children's interactions with their environment.
In the area of pesticide use patterns, our studies have taught us that pesticide products are likely
to be found in nearly 9 out of every 10 homes. The most frequently applied of these products
typically contain pyrethrins and pyrethroids (namely, permethrin, cypermethrin, and allethrin).
The applications are more likely to be performed by an occupant than by a professional, with
"crack-and-crevice" type applications favored over either the broadcast or total release aerosol
types. The application frequencies appear to be higher in warmer climates, but no differences
based on population density (urban vs. rural) or other socio-demographic factors including race,
ethnicity, home type, income, and level of education are evident. Despite much effort in
questionnaire development, we have had little success in correlating questionnaire responses
with residue measurements. More effort is still needed to improve questionnaires and to ensure
uniformity in inventory forms in future studies. Target populations for future studies should be
chosen from areas that extend outside the limited geographic regions that have previously been
studied to capture divergent use patterns, but previously studied populations should also be
included to document trends.
We have learned a great deal about spatial and temporal distributions of pesticide residues.
Indoor air concentrations are typically ten-fold higher than outdoor concentrations, but
surprisingly high outdoor air concentrations have also been measured. In the absence of any
recent application, concentrations in indoor air are strongly influenced by vapor pressure.
Immediately following an application, airborne concentrations peak within 24 hours and produce
a concentration gradient with levels decreasing with distance from the application site. Southern
states do have higher airborne concentrations than Northern states, but there is considerable
overlap. Population density (urban vs. rural) and income level differences are evident. With
surface residues, considerable variability exists not only among rooms but also in different
locations within a room. Substantial translocation of pesticides from application surfaces to
adjacent surfaces, and from outdoor surfaces to indoor surfaces has been observed. Cleaning
activities and ventilation have been found to be important for both air and surface concentrations.
Much, though not all, of what we have learned about spatial and temporal variability has come
from organophosphate pesticides, and more studies with pyrethroids are needed.
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These studies have added merit to earlier hypotheses that dermal transfer and indirect ingestion
are important routes of children's exposure to pesticides. In fact, the shift to less volatile, more
organophilic pyrethroid pesticides magnifies the importance of particle-bound transfer and
implies an increased significance of indirect ingestion. Substantial challenges still exist in this
area. One challenge is to incorporate into estimates of dermal exposure what we have learned
through laboratory studies of the importance of skin condition, contact motion, and number of
contacts. Another challenge is to standardize the collection methods used to measure the surface
residues that are a key part of dermal exposure estimates. A third challenge is to improve our
indirect ingestion exposure algorithms to ensure that we are not missing major transfer
mechanisms that may bridge the gap between what we are estimating as intake and what we are
measuring as excreted.
Analysis of the dietary ingestion components of our studies produce intake estimates that suggest
dietary ingestion may often be the dominant route of exposure (even with pyrethroids despite the
increased importance of the dermal and indirect ingestion routes). Low detection frequencies in
food measurements, however, increase uncertainty, as does the questionable reliability of
duplicate diet estimates for young children. Improvements are still essential in both the sample
collection and the chemical analysis methods. Large differences in dietary exposure estimates
among children in the same studies point to a need for a better understanding of the variability in
dietary exposure.
Clearly, more information is needed to assess the relative importance of the exposure routes
under different conditions and with pesticides from diverse compound classes. More work is
necessary to reconcile aggregate exposure estimates with levels of biomarkers measured in urine.
Moreover, more work is needed to better understand how exposures and important exposure
factors differ across age groups, as children move through different developmental stages.
We anticipate that the analyses presented in this report will be useful to the EPA Program
Offices, including the Office of Pesticide Programs and the Office of Children's Health
Protection, in their risk assessment and management activities. Although much of this high-
quality, real-world data has already been made available to the Program Offices piecemeal and
by publication in the peer reviewed literature, we expect consideration of the data collectively to
provide added value to the results of individual studies. Admittedly there are limitations inherent
in the comparisons: studies were performed in different seasons, in different years, using
different methods, and with different sample sizes. We are confident, however, that these
analyses will facilitate more accurate exposure and risk assessments, thereby strengthening
regulatory actions aimed at reducing risk, and helping to ensure that pesticides are appropriately
regulated.
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164
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APPENDIX A: Summary Statistics
165
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Air Concentrations
Table A.I Summary statistics for airborne chlorpyrifos concentrations (ng/m3) by study.
Study
NHEXAS-AZ
MNCPES
CTEPP-NC
CTEPP-OH
JAX
CHAMACOS
CPPAES (Day 1)
Test House (Day 1)
Location
Indoor
Outdoor
Personal
Indoor
Outdoor
Indoor
Outdoor
Indoor
Outdoor
Indoor
Outdoor
Indoor
Outdoor
Indoor
Indoor
N
14
3
61
80
52
148
140
147
126
9
9
20
19
10
6
%Det
50
0
95
93
6
100
83
98
75
100
56
100
84
100
100
Mean
25.9
NC
6.05
5.61
0.09
17.5
1.00
6.24
0.39
30.0
3.05
2.0
1.2
204
431
SD
44.6
NC
17.6
10.1
NC
39.3
4.02
13.8
0.75
23.3
2.35
1.1
1.1
247
376
GM
8.13
NC
1.91
1.71
NC
6.45
0.30
2.26
0.21
24.3
2.06
1.8
0.8
86.3
301
GSD
4.7
NC
4.2
5.1
NC
4.0
3.6
3.7
2.7
1.9
2.8
1.6
2.3
5.1
2.6
Min
<3.2
NC
0.10
0.10
O.10
0.31
O.10
0.10
0.10
9.81
<1.0
0.6
O.3
4.55
100
25th
<3.2
NC
0.93
0.50
O.10
2.26
0.11
0.93
0.07
18.3
<1.0
1.5
0.5
23.9
115
50th
3.37
NC
1.52
1.85
O.10
6.07
0.28
1.75
0.20
20.4
3.77
1.9
0.90
150
290
75th
31.6
NC
4.61
4.40
O.10
17.3
0.64
5.82
0.39
32.4
4.94
2.3
1.5
312
790
95th
165
NC
16.9
30.3
0.19
62.2
3.99
21.7
1.13
84.9
6.62
4.4
5.5
816
1000
Max
165
NC
135
49.5
0.91
391
45.9
98.0
6.50
84.9
6.62
5.9
5.5
816
1000
NC, not calculated due to low detection frequency
166
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Table A.2 Summary statistics for airborne diazinon concentrations (ng/m3) by study.
Study
NHEXAS -AZ
MNCPES
CTEPP-NC
CTEPP-OH
JAX
CHAMACOS
DIYC
PET
Location
Indoor
Outdoor
Personal
Indoor
Outdoor
Indoor
Outdoor
Indoor
Outdoor
Indoor
Outdoor
Indoor
Outdoor
Indoor
Indoor
N
14
o
J
48
73
52
148
140
147
143
9
9
20
19
16
60
%Det
64
0
65
66
12
100
52
98
74
78
67
100
100
100
77
Mean
30.9
NC
1.88
1.68
0.29
36.4
0.59
11.8
1.09
7.18
3.45
5.2
5.3
2280
127
SD
61.4
NC
7.86
5.76
NC
202
3.70
48.0
6.91
8.45
2.63
9.8
6.1
1790
196
GM
7.22
NC
0.34
0.35
NC
2.42
0.13
1.41
0.19
3.43
1.89
2.5
3.3
1470
25.8
GSD
5.4
NC
4.5
4.7
NC
6.0
3.0
5.3
3.3
4.7
4.2
2.8
2.6
3.0
10.7
Min
<2.0
NC
O.10
O.10
0.10
0.14
0.10
O.10
O.10
O.40
0.40
1.0
1.0
245
O.85
25th
<2.0
NC
O.10
O.10
0.10
0.66
0.10
0.51
O.10
3.43
0.40
1.3
1.4
541
7.60
50th
5.59
NC
0.28
0.27
0.10
2.03
0.09
0.97
0.15
4.64
3.53
1.8
2.8
1840
45.6
75th
12.0
NC
0.82
0.81
0.10
5.09
0.22
2.41
0.33
8.05
5.78
2.8
5.3
4060
163
95th
220
NC
4.66
8.59
0.22
63.7
0.98
56.9
1.49
28.0
6.76
29
21
4900
562
Max
220
NC
54.5
47.1
10.2
1780
42.8
482
78.9
28.0
6.76
44
21
4900
1040
NC, not calculated due to low detection frequency
Table A.3 Summary statistics for airborne malathion concentrations (ng/m3) by study.
Study
NHEXAS-AZ
MNCPES
JAX
CHAMACOS
Location
Indoor
Outdoor
Indoor
Outdoor
Indoor
Outdoor
Indoor
Outdoor
N
14
3
88
51
9
9
20
19
%Det
14
33
67
12
0
11
15
37
Mean
NC
NC
1.53
NC
NC
NC
NC
NC
SD
NC
NC
1.87
NC
NC
NC
NC
NC
GM
NC
NC
0.59
NC
NC
NC
NC
NC
GSD
NC
NC
5.3
NC
NC
<1.4
NC
NC
Min
<3.0
<3.0
O.10
O.10
NC
<1.4
0.5
0.5
25th
<3.0
<3.0
O.10
O.10
NC
<1.4
0.5
0.5
50th
<3.0
<3.0
1.18
O.10
NC
<1.4
0.5
0.5
75th
<3.0
6.85
2.11
O.10
NC
<1.4
0.5
2.6
95th
5.61
6.85
4.82
0.76
NC
6.57
5.6
17
Max
5.61
6.85
13.0
1.95
NC
6.57
7.8
17
NC, not calculated due to low detection frequency
167
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Table A.4 Summary statistics for airborne c/'s-permethrin concentrations (ng/m3) by study.
Study
MNCPES
CTEPP-NC
CTEPP-OH
JAX
CHAMACOS
Location
Personal
Indoor
Outdoor
Indoor
Outdoor
Indoor
Outdoor
Indoor
Outdoor
Indoor
Outdoor
N
64
89
51
148
140
147
143
9
9
20
20
%Det
86
69
43
65
19
22
21
44
56
40
32
Mean
0.78
0.53
NC
1.91
NC
NC
NC
NC
1.55
NC
NC
SD
2.21
2.34
NC
4.83
NC
NC
NC
NC
0.80
NC
NC
GM
0.23
0.11
NC
0.42
NC
NC
NC
NC
1.34
NC
NC
GSD
4.1
3.8
NC
5.5
NC
NC
NC
NC
1.8
NC
NC
Min
0.09
O.09
O.04
O.10
0.10
0.40
0.40
<1.0
<1.0
O.6
0.6
25th
0.09
O.09
O.04
O.10
0.10
0.40
0.40
<1.0
<1.0
O.6
0.6
50th
0.20
0.09
O.04
0.41
0.10
0.40
0.40
<1.0
2.13
O.6
0.6
75th
0.61
0.18
0.06
1.43
0.10
0.40
0.40
2.21
2.22
0.77
1.1
95th
2.07
1.26
0.15
7.79
0.47
1.63
0.95
92.5
2.29
1.2
1.4
Max
15.7
20.9
0.23
34.4
1.62
6.50
1.78
92.5
2.29
1.3
1.4
NC, not calculated due to low detection frequency
Table A.5 Summary statistics for airborne trans-permethnn concentrations (ng/m3) by study.
Study
MNCPES
CTEPP-NC
CTEPP-OH
JAX
CHAMACOS
Location
Personal
Indoor
Outdoor
Indoor
Outdoor
Indoor
Outdoor
Indoor
Outdoor
Indoor
Outdoor
N
68
96
51
148
140
147
143
9
9
19
18
%Det
63
42
14
63
19
19
17
67
78
16
0
Mean
0.61
NC
NC
1.72
NC
NC
NC
17.8
3.51
NC
NC
SD
1.95
NC
NC
4.89
NC
NC
NC
43.7
3.01
NC
NC
GM
0.11
NC
NC
0.35
NC
NC
NC
3.49
2.54
NC
NC
GSD
5.3
NC
NC
5.3
NC
NC
NC
5.3
2.4
NC
NC
Min
O.09
O.09
O.09
0.10
0.10
0.40
O.40
<1.0
<1.0
0.6
0.6
25th
O.09
O.09
O.09
0.10
0.10
0.40
O.40
<1.0
2.08
0.6
0.6
50th
O.09
O.09
O.09
0.27
0.10
0.40
O.40
3.06
2.50
0.6
0.6
75th
0.38
0.09
O.09
1.16
0.10
0.40
O.40
6.38
4.55
0.6
0.6
95th
1.72
1.26
0.48
7.16
0.30
1.04
0.66
134
10.2
1.8
0.6
Max
13.9
18.0
8.12
40.9
1.01
6.84
1.32
134
10.2
1.8
0.6
NC, not calculated due to low detection frequency
168
-------
Table A.6 Summary statistics for airborne TCPy concentrations (ng/m3) by study.
Study
CTEPP-NC
CTEPP-OH
Location
Indoor
Outdoor
Indoor
Outdoor
N
148
140
144
133
%Det
99
88
100
88
Mean
4.68
0.44
1.97
0.32
SD
12.47
0.91
4.62
0.48
GM
1.78
0.24
0.84
0.22
GSD
3.8
2.6
3.1
2.2
Min
0.09
O.09
0.09
O.09
25th
0.81
0.13
0.43
0.13
50th
1.77
0.22
0.65
0.21
75th
3.99
0.40
1.74
0.36
95th
14.3
1.57
8.60
0.88
Max
1040
9.06
42.0
4.86
Table A.7 Summary statistics for airborne IMP concentrations (ng/m3) by study.
Study
CTEPP-OH
Location
Indoor
Outdoor
N
147
141
%Det
95
86
Mean
1.52
1.48
SD
3.62
5.93
GM
0.64
0.36
GSD
3.1
3.7
Min
0.09
0.09
25th
0.35
0.14
50th
0.53
0.33
75th
1.04
0.77
95th
5.68
2.44
Max
27.4
49.6
169
-------
Dust and Soil Concentrations and Loadings
Table A.8 Summary statistics for chlorpyrifos concentrations measured in soil (ng/g).
Study
MNCPES
CTEPP (NC)
CTEPP (OH)
CCC
Method
Soil
Soil
Soil
Soil
Group
Home
Home
Daycare
Home
Daycare
Daycare
n
102
128
13
127
16
117
%Det
3
19
8
39
38
23
Mean
NC
NC
NC
NC
NC
NC
SD
NC
NC
NC
NC
NC
NC
GM
NC
NC
NC
NC
NC
NC
GSD
NC
NC
NC
NC
NC
NC
Min
<10
O.5
O.5
0.5
0.5
<5
25th
<10
O.5
O.5
0.5
0.5
<5
50th
<10
O.5
O.5
0.5
0.5
<5
75th
<10
O.5
O.5
3.92
1.32
<5
95th
<10
16.7
0.76
13.8
6.16
26.8
Max
24.9
1170
0.76
2930
6.16
1150
NC, Not calculated
Table A.9 Summary statistics for chlorpyrifos measured in dust, presented as both loading (ng/cm2) and concentration (ng/g).
W> fT^
II
^S
Concentration
(ng/g)
Study
NHEXAS-AZ
CTEPP (NC)
CTEPP (OH)
CHAMACOS
CTEPP (NC)
CTEPP (OH)
CHAMACOS
Method
Vacuum
Floor Dust
Floor Dust
House Dust
Floor Dust
Floor Dust
House Dust
Group
Children < 12
Home
Daycare
Home
Daycare
All
Home
Daycare
Home
Daycare
All
n
13
121
19
120
23
20
121
19
120
23
20
%Det
77
100
100
100
100
95
100
100
100
100
95
Mean
0.34
0.14
0.21
0.106
0.19
0.014
413
237
871
272
370
SD
0.80
0.63
0.37
0.54
0.33
0.030
1430
256
5030
285
684
GM
0.012
0.140
0.055
0.008
0.044
0.005
137
132
70.4
168
128
GSD
23
7.3
6.4
6.9
6.8
4.2
3.7
3.5
5.1
2.7
4.7
Min
0.002
0.0001
0.0009
0.0001
0.003
0.001
11.5
12.4
3.62
40.6
<4
25th
0.002
0.0034
0.014
0.002
0.008
0.004
47.5
94.2
23.1
67.0
78.5
50th
0.007
0.0094
0.057
0.006
0.045
0.005
135
142
52.0
174
120
75th
0.086
0.056
0.18
0.02
0.19
0.008
281
254
149
430
242
95th
2.81
0.42
1.32
0.35
0.89
0.098
1180
921
1410
897
2180
Max
2.81
5.16
1.32
5.41
1.34
0.12
15100
921
49600
1110
2840
170
-------
Table A. 10 Summary statistics for diazinon concentrations measured in soil (ng/g).
Study
MNCPES
CTEPP (NC)
CTEPP (OH)
CCC
PET
Method
Soil
Soil
Soil
Soil
Soil
Group
Home
Home
Daycare
Home
Daycare
Daycare
Home
n
102
129
13
127
16
117
4
%Det
4
18
0
34
19
20
100
Mean
NC
NC
NC
NC
NC
NC
16900
SD
NC
NC
NC
NC
NC
NC
6140
GM
NC
NC
NC
NC
NC
NC
16000
GSD
NC
NC
NC
NC
NC
NC
1.45
Min
<10
O.5
0.5
0.5
0.5
<2
10100
25th
<10
O.5
0.5
0.5
0.5
<2
12600
50th
<10
O.5
0.5
0.5
0.5
<2
16200
75th
<10
O.5
0.5
0.99
0.5
<2
21100
95th
<10
4.24
0.5
4.72
7.07
21.9
24900
Max
24.9
5470
0.5
28500
7.07
110000
2490
NC, Not calculated
Table A.I 1 Summary statistics for diazinon measured in dust, presented as both loading (ng/cm2) and concentration (ng/g).
ฃP?T
lง
^S
Concentration
(ng/g)
Study
NHEXAS-AZ
CTEPP (NC)
CTEPP (OH)
CHAMACOS
PET
CTEPP (NC)
CTEPP (OH)
CHAMACOS
PET
Method
Vacuum
Floor Dust
Floor Dust
House Dust
Floor Dust
Floor Dust
Floor Dust
House Dust
Floor Dust
Group
Children < 12
Home
Daycare
Home
Daycare
All
All
Home
Daycare
Home
Daycare
All
All
n
13
121
19
9120
23
20
17
121
19
120
23
20
17
%Det
54
96
100
96
100
100
100
96
100
96
100
100
100
Mean
0.035
0.0964
0.571
0.094
0.1
0.0065
5.72
282
439
1360
260
202
29200
SD
0.062
0.638
2.25
0.59
0.27
0.018
16.5
1380
1560
8470
472
562
53000
GM
0.007
0.0025
0.0235
0.004
0.02
0.0022
0.44
24.4
58.6
34.3
73.7
53.9
4990
GSD
7.1
8.8
11
7.5
5.9
3.2
2.4
5.1
5.6
7.2
4.8
3.9
2.1
Min
0.002
0.0003
0.0002
O.0003
0.001
0.0004
0.005
<2
3.06
<2
5.08
7.75
256
25th
0.002
0.0006
0.0032
0.001
0.004
0.0010
0.092
7.90
26.0
9.72
28.4
21.3
654
50th
0.002
0.0016
0.0177
0.002
0.022
0.0021
0.35
17.5
65.2
19.8
40.0
58.8
312
75th
0.035
0.0106
0.154
0.01
0.06
0.0032
1.4
54.4
138
73.2
210
74.4
18500
95th
0.18
0.123
9.86
0.31
0.39
0.048
68
388
6880
1710
1610
1470
149000
Max
0.18
5.63
9.86
6.24
1.25
0.081
68
11000
6880
79900
1630
2550
149000
NC, Not calculated
171
-------
Table A. 12 Summary statistics for c/'s-permethrin concentrations measured in soil (ng/g).
Study
MNCPES
CTEPP (NC)
CTEPP (OH)
CCC
Method
Soil
Soil
Soil
Soil
Group
Home
Home
Daycare
Home
Daycare
Daycare
n
102
128
13
127
16
117
%Det
3
19
8
39
0
23
Mean
NC
NC
NC
NC
NC
NC
SD
NC
NC
NC
NC
NC
NC
GM
NC
NC
NC
NC
NC
NC
GSD
NC
NC
NC
NC
NC
NC
Min
<10
<0.5
<0.5
O.5
O.5
<5
25th
<10
0.5
0.5
O.5
O.5
<5
50th
<10
0.5
0.5
O.5
O.5
<5
75th
<10
0.5
0.5
O.5
O.5
<5
95th
<10
16.7
0.76
13.8
O.5
26.8
Max
24.9
1170
0.76
2930
O.5
1150
NC, Not calculated
Table A. 13 Summary statistics for c/'s-permethrin measured in dust, presented as both loading (ng/cm2) and concentration (ng/g).
60 fT^
n
3^
Concentration
(ng/g)
Study
CTEPP (NC)
CTEPP (OH)
CHAMACOS
CTEPP (NC)
CTEPP (OH)
CHAMACOS
Method
Floor Dust
Floor Dust
House Dust
Floor Dust
Floor Dust
House Dust
Group
Home
Daycare
Home
Daycare
All
Home
Daycare
Home
Daycare
All
n
121
20
120
23
20
121
20
120
23
20
%Det
100
100
100
100
100
100
100
100
100
100
Mean
0.975
5.44
0.83
0.78
0.030
6080
3500
2320
1460
923
SD
3.02
19.6
4.32
1.36
0.063
29400
6760
8050
1300
2010
GM
0.104
0.507
0.063
0.26
0.013
995
1140
572
968
317
GSD
8.8
8.3
7.5
5.0
3.4
4.6
4.3
4.3
2.6
4.2
Min
0.0012
0.005
0.002
0.01
0.0013
67.1
113
16.6
127
25.6
25th
0.026
0.181
0.015
0.07
0.0057
347
455
197
418
113
50th
0.103
0.694
0.045
0.27
0.015
804
806
470
1010
345
75th
0.411
1.78
0.25
0.68
0.021
1850
2230
1550
1850
598
95th
4.94
46.9
3.85
4.82
0.17
21100
19700
7630
3830
5810
Max
23.0
88.3
45.4
5.03
0.29
311000
29000
79600
4630
9070
172
-------
Table A. 14 Summary statistics for ^raw^-permethrin concentrations measured in soil (ng/g).
Study
CTEPP (NC)
CTEPP (OH)
CCC
Method
Soil
Soil
Soil
Group
Home
Day care
Home
Day care
Daycare
n
129
13
124
14
117
%Det
22
8
6
0
16
Mean
NC
NC
NC
NC
NC
SD
NC
NC
NC
NC
NC
GM
NC
NC
NC
NC
NC
GSD
NC
NC
NC
NC
NC
Min
<0.5
<0.5
<0.5
<0.5
<5
25th
O.5
O.5
0.5
0.5
<5
50th
O.5
O.5
0.5
0.5
<5
75th
O.5
O.5
0.5
0.5
<5
95th
17.9
2.20
2.06
0.5
12.0
Max
1610
2.20
1400
0.5
136
NC, Not calculated
Table A. 15 Summary statistics for rram'-permethrin measured in dust, presented as both loading (ng/cm2) and concentration (ng/g).
60 ^
n
3^
Concentration
(ng/g)
Study
CTEPP (NC)
CTEPP (OH)
CHAMACOS
CTEPP (NC)
CTEPP (OH)
CHAMACOS
Method
Floor Dust
Floor Dust
House Dust
Floor Dust
Floor Dust
House Dust
Group
Home
Daycare
Home
Daycare
All
Home
Daycare
Home
Daycare
All
n
121
20
118
22
20
121
20
118
22
20
%Det
100
100
100
100
100
100
100
100
100
100
Mean
0.94
5.59
0.76
0.73
0.06
6120
3600
2340
1260
1860
SD
2.99
20.2
4.26
1.40
0.13
30400
7120
8320
1220
4030
GM
0.09
0.49
0.05
0.20
0.03
835
1110
453
784
655
GSD
10
8.2
8.2
6.0
3.4
5.0
4.5
5.0
2.7
4.0
Min
0.0006
0.005
0.002
0.007
0.002
51.3
125
16.5
126
43.2
25th
0.015
0.137
0.010
0.047
0.014
267
542
132
362
310
50th
0.09
0.41
0.03
0.26
0.02
629
856
344
554
608
75th
0.38
1.38
0.14
0.57
0.06
1850
1830
1270
1860
1250
95th
4.42
48.8
3.86
4.72
0.38
19400
20900
9210
3420
11300
Max
22.6
91.2
45.0
5.17
0.58
322000
29900
78800
3950
18200
173
-------
Table A. 16 Summary statistics for cyfluthrin concentrations measured in soil (ng/g).
Study
CTEPP (NC)
CTEPP (OH)
CCC
Method
Soil
Soil
Soil
Group
Home
Daycare
Home
Daycare
Daycare
n
129
13
127
16
117
%Det
12
8
17
25
10
Mean
NC
NC
NC
NC
NC
SD
NC
NC
NC
NC
NC
GM
NC
NC
NC
NC
NC
GSD
NC
NC
NC
NC
NC
Min
<5
<5
<5
<5
<6
25th
<5
<5
<5
<5
<6
50th
<5
<5
<5
<5
<6
75th
<5
<5
<5
<5
<6
95th
32.1
42.2
64.2
42.2
8.58
Max
187
42.2
644
42.2
11000
NC, Not calculated
Table A. 17 Summary statistics for cyfluthrin measured in dust, presented as both loading (ng/cm2) and concentration (ng/g).
60 fT^
a a
^ ^
^S
Concentration
(ng/g)
Study
CTEPP (NC)
CTEPP (OH)
CHAMACOS
CTEPP (NC)
CTEPP (OH)
CHAMACOS
Method
Floor Dust
Floor Dust
House Dust
Floor Dust
Floor Dust
House Dust
Group
Home
Day care
Home
Day care
All
Home
Day care
Home
Day care
All
n
121
19
119
23
20
121
19
119
23
20
%Det
48
42
74
74
10
48
42
74
74
10
Mean
NC
NC
0.056
0.37
NC
NC
NC
329
389
NC
SD
NC
NC
0.10
0.5
NC
NC
NC
482
323
NC
GM
NC
NC
0.016
0.059
NC
NC
NC
148
221
NC
GSD
NC
NC
5.6
14
NC
NC
NC
3.9
3.7
NC
Min
O.0003
O.0003
0.0003
0.0003
0.005
<10
<10
<10
<10
<100
25th
O.0003
O.0003
0.0003
0.0003
0.005
<10
<10
<10
<10
<100
50th
O.0003
O.0003
0.018
0.14
0.005
<10
<10
195
336
<100
75th
0.04
0.31
0.054
0.74
0.005
248
329
384
648
<100
95th
0.16
0.78
0.25
1.1
0.027
1660
1750
1280
890
828
Max
2.14
0.78
0.66
1.9
0.030
4100
1750
3040
1010
949
NC, Not calculated
174
-------
Table A. 18 Summary statistics for TCPy concentrations measured in soil (ng/g).
Study
CTEPP (NC)
CTEPP (OH)
Method
Soil
Soil
Group
Home
Daycare
Home
Daycare
n
129
13
127
16
%Det
71
46
80
81
Mean
3.61
NC
3.99
1.15
SD
14.9
NC
15.3
1.57
GM
0.62
NC
0.82
0.60
GSD
4.22
NC
4.35
3.17
Min
0.2
0.2
0.2
O.2
25th
0.2
0.2
0.23
0.22
50th
0.57
0.2
0.70
0.63
75th
1.25
0.35
2.02
1.35
95th
10.7
1.70
8.86
6.30
Max
111
1.70
127
6.30
NC, Not calculated
Table A. 19 Summary statistics for IMP concentrations measured in soil (ng/g).
Study
CTEPP (OH)
Method
Soil
Group
Home
Daycare
n
125
16
%Det
41
38
Mean
NC
NC
SD
NC
NC
GM
NC
NC
GSD
NC
NC
Min
O.2
0.2
25th
O.2
0.2
50th
O.2
0.2
75th
0.43
0.44
95th
2.07
1.43
Max
162
1.43
NC, Not calculated
175
-------
Total Available Surface Residue Loadings
Table A.20 Summary statistics for chlorpyrifos in Total Available Residue (ng/cm2).
Study
NHEXAS-AZ
MNCPES
ccc
JAX
CHAMACOS
CPPAES
Test House
Method
Surface Wipe
LWW
Surface Wipe
Surface Wipe
Surface Wipe
LWW
Deposition
Coupons
Deposition
Coupons
Surface Wipe
Group
Window Sill
Floor
Floor
Desk/Table
Floor (Screening)
Floor
Play Area
All
Living Area/Kitchen
(Pre-application)
Living Area/Kitchen
Bedroom
(Pre-application)
Bedroom
Cumulative
Interval
Bedroom
Den
Kitchen
All
Kitchen
n
6
99
168
80
46
9
9
20
20
97
20
64
39
40
5
28
24
57
9
%Det
17
62
64
73
87
78
67
95
60
100
65
100
100
100
100
100
100
100
100
Mean
NC
1.04
0.38
0.18
4.87
0.85
0.32
0.060
0.29
2.39
0.41
1.97
2.12
1.24
1.89
2.23
31.6
14.6
1548
SD
NC
0.41
2.28
0.53
20.32
1.11
0.77
0.057
0.38
4.30
0.48
4.84
2.66
1.59
2.12
2.57
56.4
39.0
2793
GM
NC
0.83
0.027
0.036
0.44
0.21
0.014
0.037
0.1
0.95
0.16
0.52
0.99
0.62
1.07
1.64
11.5
3.58
627
GSD
NC
1.4
7.7
6.4
12.5
12.0
17.0
2.96
4.91
3.68
5.24
4.40
4.17
3.96
3.81
2.07
4.16
4.46
3.71
Min
0.07
<1.15
-------
Table A.21 Summary statistics for diazinon in Total Available Residue (ng/cm2).
Study
NHEXAS-AZ
MNCPES
ccc
JAX
CHAMACOS
DIYC
Method
Surface Wipe
LWW
Surface Wipe
Surface Wipe
Surface Wipe
Surface Wipe
Group
Window Sill
Floor
Floor
Desk/Table
Floor (Screening)
Floor
Play Area
All
Floor
(Pre-application)
Floor
n
6
99
168
80
46
9
9
20
7
35
%Det
0
7
54
41
89
44
33
95
86
100
Mean
NC
NC
0.21
NC
1.35
NC
NC
0.041
7.06
12.7
SD
NC
NC
1.44
NC
5.07
NC
NC
0.033
6.87
20.4
GM
NC
NC
0.011
NC
0.11
NC
NC
0.024
4.71
6.35
GSD
NC
NC
9.1
NC
10.5
NC
NC
3.73
2.7
2.9
Min
<2.0
<3.5
0.001
0.001
O.002
O.002
0.002
0.005
0.3
0.71
25th
<2.0
<3.5
0.002
0.002
0.03
O.002
0.002
0.011
2.61
3.93
50th
<2.0
<3.5
0.004
0.002
0.11
O.002
0.002
0.038
3.85
5.54
75th
<2.0
<3.5
0.06
0.02
0.52
0.34
0.002
0.066
10.3
7.54
95th
<2.0
3.55
0.53
0.28
3.33
1.43
3.99
0.093
20.8
71.6
Max
<2.0
7.01
18.3
2.40
32.9
1.43
3.99
0.096
20.8
85.1
NC, Not calculated
LWW, Lioy-Weisel-Wainman sampler
Table A.22 Summary statistics for cis-permethrin in Total Available Residue (ng/cm2).
Study
CCC
JAX
CHAMACOS
Method
Surface Wipes
Surface Wipes
Surface Wipe
Group
Floor
Surfaces
Floor (Screening)
Floor
Play Area
All
n
168
80
46
9
9
20
%Det
60
44
87
78
67
85
Mean
0.14
1.55
8.46
8.56
1.57
0.21
SD
0.36
10.5
15.5
16.4
3.2
0.36
GM
0.022
0.015
0.93
0.35
0.09
0.1
GSD
6.3
8.4
19.9
28.3
23.3
6.8
Min
0.002
0.005
0.005
O.005
O.005
O.005
25th
0.004
0.005
0.19
0.13
O.005
0.053
50th
0.02
0.005
2.22
0.24
0.04
0.10
75th
0.08
0.06
10.0
1.69
0.89
0.21
95th
0.79
0.46
32.2
42.4
9.77
1.1
Max
2.81
89.8
75.8
42.4
9.77
1.7
177
-------
Table A.23 Summary statistics for trans-permethrin in Total Available Residue (ng/cm2).
Study
CCC
JAX
CHAMACOS
Method
Surface Wipe
Surface Wipe
Surface Wipe
Group
Floor
Desk/Table
Floor (Screening)
Floor
Play Area
All
n
168
80
46
9
9
20
%Det
62
60
89
78
89
95
Mean
0.25
3.23
10.2
12.9
2.06
0.43
SD
0.71
24.7
19.4
24.9
4.41
0.77
GM
0.031
0.027
1.18
0.44
0.14
0.18
GSD
8.1
9.0
19.3
34.1
19.8
5.1
Min
O.005
O.005
0.005
0.005
0.005
O.002
25th
O.005
O.005
0.26
0.12
0.02
0.14
50th
0.03
0.02
2.93
0.34
0.05
0.23
75th
0.17
0.11
11.7
3.48
1.45
0.39
95th
1.17
0.92
40.0
66.6
13.6
2.3
Max
6.96
219
94.3
66.6
13.6
3.6
Table A.24 Summary statistics for cyfluthrin in Total Available Residue (ng/cm2).
Study
CCC
JAX
CHAMACOS
Method
Surface Wipe
Surface Wipe
Surface Wipe
Group
Floor
Desk/Table
Floor (Screening)
Floor
Play Area
All
n
168
80
46
9
9
20
%Det
7
1
20
33
11
5
Mean
NC
NC
NC
NC
NC
NC
SD
NC
NC
NC
NC
NC
NC
GM
NC
NC
NC
NC
NC
NC
GSD
NC
NC
NC
NC
NC
NC
Min
0.006
0.006
0.006
O.006
O.006
O.05
25th
0.006
0.006
0.006
O.006
O.006
O.05
50th
0.006
0.006
0.006
O.006
O.006
O.05
75th
0.006
0.006
0.006
0.04
O.006
O.05
95th
0.4
0.006
4.33
10.1
3.45
O.05
Max
6.87
0.80
13.8
10.1
3.45
0.40
NC, Not calculated
178
-------
Transferable Surface Residue Loadings
Table A.25 Summary statistics for chlorpyrifos in Transferable Residue (ng/cm2).
Study
MNCPES
CTEPP (NC)
CTEPP (OH)
CHAMACOS
CPPAES
Test House
Method
CIS Press
Surface Wipe
PUF Roller
Surface Wipe
PUF Roller
CIS Press
Surface Wipe
CIS Press
PUF Roller
Group
Floor
Surface
Home Floor
Kitchen Counter
Home
Home Floor
Kitchen Counter
Home
All
Floor
Den/Kitchen
Den/Kitchen
n
102
102
28
18
18
21
13
13
20
41
16
6
%Det
8
5
89
89
94
86
62
85
0
100
94
100
Mean
NC
NC
0.02
0.03
0.01
0.19
0.068
0.25
NC
0.052
1.02
0.030
SD
NC
NC
0.05
0.04
0.023
0.84
0.21
0.89
NC
0.054
2.06
0.059
GM
NC
NC
0.0063
0.008
0.005
0.0043
0.0025
0.0026
NC
0.026
0.26
0.007
GSD
NC
NC
4.6
5.8
4.5
8.8
10
11
NC
4.02
5.13
5.97
Min
<0.33
0.33
0.0007
0.0007
O.0004
O.0007
O.0007
0.0004
0.09
0.002
O.03
0.001
25th
O.33
0.33
0.0031
0.003
0.0015
0.001
O.0007
0.001
0.09
0.014
0.11
0.002
50th
O.33
0.33
0.0066
0.007
0.0035
0.003
0.001
0.002
0.09
0.031
0.23
0.0045
75th
O.33
0.33
0.012
0.045
0.009
0.013
0.006
0.004
0.09
0.074
0.52
0.017
95th
0.44
0.33
0.15
0.14
0.072
0.11
0.76
3.22
0.09
0.163
6.86
0.15
Max
63.5
0.70
0.21
0.14
0.072
3.86
0.76
3.22
0.09
0.179
6.86
0.15
NC, Not calculated
179
-------
Table A.26 Summary statistics for diazinon in Transferable Residue (ng/cm2).
Study
MNCPES
CTEPP (NC)
CTEPP (OH)
CHAMACOS
DIYC
Method
CIS Press
Surface Wipe
PUF Roller
Surface Wipe
PUF Roller
CIS Press
CIS Press
Group
Floor
Surface
Home Floor
Kitchen Counter
Home
Home Floor
Kitchen Counter
Home
All
Floor
Counter
Play Area
n
102
102
28
18
18
21
13
13
20
9
o
6
o
5
%Det
8
8
68
61
67
38
31
54
0
89
67
33
Mean
NC
NC
0.056
0.063
0.075
NC
NC
0.01
NC
10.9
NC
NC
SD
NC
NC
0.19
0.21
0.22
NC
NC
0.03
NC
9.11
NC
NC
GM
NC
NC
0.002
0.003
0.004
NC
NC
0.001
NC
6.5
NC
NC
GSD
NC
NC
8.4
8.8
13
NC
NC
1.71
NC
3.5
NC
NC
Min
0.14
0.14
0.0007
O.0007
O.0004
O.0007
0.0007
0.0004
0.02
<1.2
<1.2
<1.2
25th
0.14
0.14
0.0007
O.0007
O.0004
O.0007
0.0007
0.0004
0.02
1.24
NC
NC
50th
0.14
0.14
0.001
0.002
0.003
O.0007
0.0007
0.001
0.02
3.78
3.18
<1.2
75th
0.14
0.14
0.003
0.008
0.034
0.001
0.001
0.002
0.02
11.7
NC
NC
95th
0.55
1.13
0.51
0.87
0.93
0.01
0.21
0.11
0.02
23.9
NC
NC
Max
13.0
2.68
0.91
0.87
0.93
0.05
0.21
0.11
0.02
23.9
9.46
3.89
NC, Not calculated
Table A.27 Summary statistics for c/s-permethrin in Transferable Residue (ng/cm2).
Study
CTEPP (NC)
CTEPP (OH)
CHAMACOS
Method
Surface Wipe
PUF Roller
Surface Wipe
PUF Roller
CIS Press
Group
Home Floor
Kitchen Counter
Home
Home Floor
Kitchen Counter
Home
All
n
28
18
18
21
13
13
20
%Det
93
83
83
71
39
69
0
Mean
0.161
3.05
0.164
0.28
NC
0.035
NC
SD
0.263
11.7
0.319
1.13
NC
0.08
NC
GM
0.034
0.044
0.020
0.011
NC
0.004
NC
GSD
8.6
24
13
12
NC
9.3
NC
Min
0.0007
O.0007
O.0004
O.0007
0.0007
0.0004
0.2
25th
0.0071
0.0062
0.0038
O.0007
0.0007
0.0004
0.2
50th
0.0443
0.0596
0.0229
0.009
0.0007
0.004
0.2
75th
0.192
0.361
0.139
0.064
0.006
0.012
0.2
95th
0.832
50.1
1.13
0.19
0.78
0.29
0.2
Max
0.874
50.1
1.13
5.2
0.78
0.29
0.2
NC, Not calculated
180
-------
Table A.28 Summary statistics for trans-permethrin in Transferable Residue (ng/cm2).
Study
CTEPP (NC)
CTEPP (OH)
CHAMACOS
Method
Surface Wipe
PUF Roller
Surface Wipe
PUF Roller
CIS Press
Group
Home Floor
Kitchen Counter
Home
Home Floor
Kitchen Counter
Home
All
n
28
18
18
21
13
13
20
%Det
93
83
83
71
39
69
0
Mean
0.157
3.48
0.18
0.28
NC
0.03
NC
SD
0.268
13.5
0.34
1.12
NC
0.08
NC
GM
0.027
0.041
0.018
0.011
NC
0.003
NC
GSD
9.8
26
14
13
NC
8.2
NC
Min
O.0007
O.0007
0.0004
0.0007
0.0007
O.0004
O.2
25th
0.005
0.006
0.003
0.0007
0.0007
O.0004
O.2
50th
0.04
0.026
0.02
0.01
0.0007
0.003
O.2
75th
0.19
0.375
0.17
0.07
0.005
0.008
O.2
95th
0.83
57.4
1.16
0.2
0.79
0.29
O.2
Max
1.01
57.4
1.16
5.18
0.79
0.29
O.2
NC, Not calculated
Table A.29 Summary statistics for cyfluthrin using in Transferable Residue (ng/cm2).
Study
CTEPP (NC)
CTEPP (OH)
CHAMACOS
Method
Surface Wipe
PUF Roller
Surface Wipe
PUF Roller
CIS Press
Group
Home Floor
Kitchen Counter
Home
Home Floor
Kitchen Counter
Home
All
n
28
18
18
21
13
13
20
%Det
7
0
78
10
0
0
0
Mean
NC
NC
0.11
NC
NC
NC
NC
SD
NC
NC
0.10
NC
NC
NC
NC
GM
NC
NC
0.05
NC
NC
NC
NC
GSD
NC
NC
5.4
NC
NC
NC
NC
Min
0.0007
0.0007
0.0004
O.0007
O.0007
O.0004
0.2
25th
0.0007
0.0007
0.02
O.0007
O.0007
O.0004
0.2
50th
0.0007
0.0007
0.10
O.0007
O.0007
O.0004
0.2
75th
0.0007
0.0007
0.16
O.0007
O.0007
O.0004
0.2
95th
0.05
0.0007
0.41
0.041
O.0007
O.0004
0.2
Max
0.13
0.0007
0.41
0.078
O.0007
O.0004
0.2
NC, Not calculated
181
-------
Solid Food Concentrations and Intakes
Table A.30 Summary statistics for chlorpyrifos measured in solid food, presented as both intake (ug/day) and concentration (ug/kg).
II
a ^
Concentration
(Jig/kg)
Study
MNCPES
CTEPP-NC
CTEPP-OH
JAX
NHEXAS-AZ
MNCPES
CTEPP (NC)
CTEPP (OH)
JAX
CHAMACOS
Method
Dup Diet
Dup Diet/
Dup Plate
Dup Diet/
Dup Plate
Dup Diet
Dup Diet
Dup Diet
Dup Diet/
Dup Plate
Dup Diet/
Dup Plate
Dup Diet
Dup Diet
Group
All
All
All
All
< 12 years
All
Home
Daycare
Home
Daycare
All
All
n
96
129
125
9
20
96
129
24
125
29
9
17
%Det
91
75
78
100
15
88
65
54
66
69
100
6
Mean
0.42
0.20
0.13
1.3
NC
0.79
0.57
0.23
0.38
0.20
1.3
NC
SD
0.64
0.66
0.18
1.6
NC
1.2
1.8
0.25
0.61
0.19
2.3
NC
GM
0.24
0.079
0.073
0.76
NC
0.51
0.20
0.14
0.19
0.15
0.51
NC
GSD
2.9
3.3
2.7
3.0
NC
2.3
3.4
2.7
3.0
2.3
4.2
NC
Min
<0.12
0.024
0.024
0.12
<1.0
O.26
O.08
0.08
0.08
0.08
0.050
<1.0
25th
0.14
0.029
0.035
0.48
<1.0
0.29
O.08
0.08
0.08
O.08
0.25
<1.0
50th
0.26
0.093
0.071
1.1
<1.0
0.53
0.19
0.10
0.19
0.14
0.38
<1.0
75th
0.38
0.18
0.13
1.2
<1.0
0.81
0.39
0.35
0.39
0.24
1.5
<1.0
95th
1.6
0.64
0.40
5.2
5.7
2.4
2.1
0.85
1.6
0.56
7.4
1.4
Max
4.8
7.3
1.3
5.2
7.2
7.1
20
0.95
3.5
0.88
7.4
1.4
Dup Diet, Duplicate Diet; Dup Plate, Duplicate Plate
NC, Not calculated
182
-------
Table A.31 Summary statistics for diazinon measured in solid food, presented as both intake (ug/day) and concentration (ug/kg).
p
T^A
s -5
M =ฃ
Concentration
(ug/kg)
Study
MNCPES
CTEPP-NC
CTEPP-OH
DIYC
JAX
NHEXAS-AZ
MNCPES
CTEPP (NC)
CTEPP (OH)
DIYC
JAX
CHAMACOS
Method
Dup Diet
Dup Diet/
Dup Plate
Dup Diet/
Dup Plate
Dup Diet
Dup Diet
Dup Diet
Dup Diet
Dup Diet/
Dup Plate
Dup Diet/
Dup Plate
Dup Diet
Dup Diet
Dup Diet
Group
All
All
All
All
All
< 12 years
All
Home
Daycare
Home
Daycare
All
All
All
n
101
128
125
16
9
20
101
128
24
125
29
16
9
17
%Det
20
32
23
100
11
10
6
22
25
15
24
100
44
12
Mean
NC
NC
NC
0.42
NC
NC
NC
NC
NC
NC
NC
0.29
NC
NC
SD
NC
NC
NC
0.29
NC
NC
NC
NC
NC
NC
NC
0.25
NC
NC
GM
NC
NC
NC
0.34
NC
NC
NC
NC
NC
NC
NC
0.23
NC
NC
GSD
NC
NC
NC
2.0
NC
NC
NC
NC
NC
NC
NC
1.9
NC
NC
Min
0.019
O.024
O.024
0.095
0.35
0.7
0.2
O.08
O.08
O.08
0.08
0.12
0.04
<1
25th
0.019
O.024
O.024
0.23
0.35
0.7
0.2
O.08
O.08
O.08
0.08
0.15
0.04
<1
50th
0.019
O.024
O.024
0.30
0.35
0.7
0.2
O.08
O.08
O.08
0.08
0.17
0.04
<1
75th
0.019
0.040
O.024
0.51
0.35
0.7
0.2
O.08
0.08
O.08
0.08
0.31
0.080
<1
95th
0.12
0.095
0.073
1.1
0.67
1.8
0.22
0.41
0.17
0.18
0.20
1.01
1.05
1.0
Max
0.64
1.3
0.21
1.1
0.67
1.9
2.0
6.7
0.89
0.72
0.23
1.01
1.05
1.0
Dup Diet, Duplicate Diet; Dup Plate, Duplicate Plate
NC, Not calculated
183
-------
Table A.32 Summary statistics for c/'s-permethrin measured in solid food, presented as both intake (ug/day) and concentration (ug/kg).
II
s w)
Concentration
(ug/kg)
Study
MNCPES
CTEPP-NC
CTEPP-OH
MNCPES
CTEPP (NC)
CTEPP (OH)
JAX
Method
Dup Diet
Dup Diet
Dup Diet
Dup Diet
Dup Diet/
Dup Plate
Dup Diet/
Dup Plate
Dup Diet
Group
All
All
All
All
Home
Daycare
Home
Daycare
All
n
100
129
125
100
129
24
125
29
9
%Det
30
50
38
20
46
25
31
24
78
Mean
NC
2.7
NC
NC
NC
NC
NC
NC
1.6
SD
NC
14
NC
NC
NC
NC
NC
NC
4.2
GM
NC
0.10
NC
NC
NC
NC
NC
NC
0.19
GSD
NC
7.3
NC
NC
NC
NC
NC
NC
7.9
Min
0.019
O.024
0.024
0.024
0.08
0.08
O.08
O.08
O.02
25th
0.019
O.024
0.024
0.024
0.08
0.08
O.08
O.08
0.080
50th
0.019
0.060
0.024
0.024
0.08
0.08
O.08
O.08
0.29
75th
0.019
0.23
0.090
0.14
0.59
0.22
0.19
O.08
0.35
95th
0.92
6.8
4.8
1.5
16
5.2
8.8
2.2
13
Max
2.6
93
113
4.9
81
218
560
31
13
Dup Diet, Duplicate Diet;
NC, Not calculated
Dup Plate, Duplicate Plate
Table A.33 Summary statistics for trans-permethrin measured in solid food, presented as both intake (ug/day) and concentration
u ^>
s -5
a 5P
Concentration
(lig/kg)
Study
MNCPES
CTEPP-NC
CTEPP-OH
MNCPES
CTEPP (NC)
CTEPP (OH)
JAX
Method
Dup Diet
Dup Diet/
Dup Plate
Dup Diet/
Dup Plate
Dup Diet
Dup Diet/
Dup Plate
Dup Diet/
Dup Plate
Dup Diet
Group
All
All
All
All
Home
Daycare
Home
Daycare
All
n
101
128
125
101
128
24
125
29
9
%Det
13
50
38
7
46
25
31
24
78
Mean
NC
1.5
NC
NC
NC
NC
NC
NC
2.8
SD
NC
8.0
NC
NC
NC
NC
NC
NC
7.3
GM
NC
0.087
NC
NC
NC
NC
NC
NC
0.27
GSD
NC
6.1
NC
NC
NC
NC
NC
NC
9.8
Min
O.01
0.024
O.024
O.08
O.08
0.08
0.08
0.08
O.02
25th
O.01
0.024
O.024
O.08
O.08
0.08
0.08
0.08
0.17
50th
O.01
0.051
O.024
O.08
O.08
0.08
0.08
0.08
0.22
75th
O.01
0.19
0.069
O.08
0.58
0.18
0.18
0.08
0.45
95th
0.15
4.6
4.2
0.33
8.7
3.0
8.0
1.4
22
Max
1.4
65
90
1.9
70
149
448
27
22
Dup Diet, Duplicate Diet; Dup Plate, Duplicate Plate
NC, Not calculated
184
-------
Table A.34 Summary statistics for TCPy measured in solid food, presented as both intake (ug/day) and concentration (ug/kg).
0 >*
_ ^ TO
fง ""3
s 5P
KH ^.
Concentration
(lig/kg)
Study
CTEPP-NC
CTEPP-OH
CTEPP (NC)
CTEPP (OH)
JAX
Method
Dup Diet/
Dup Plate
Dup Diet/
Dup Plate
Dup Diet/
Dup Plate
Dup Diet/
Dup Plate
Dup Diet
Group
All
All
Home
Daycare
Home
Daycare
All
n
128
127
128
24
127
29
9
%Det
99
100
98
100
99
100
100
Mean
1.4
1.0
3.1
3.8
2.6
2.8
5.0
SD
0.97
0.90
2.8
3.3
2.6
5.0
3.7
GM
0.99
0.70
2.1
2.8
1.7
1.7
4.0
GSD
2.6
2.5
2.6
2.3
2.7
2.4
1.9
Min
O.038
0.038
0.12
0.25
O.13
0.38
2.0
25th
0.71
0.41
1.5
2.3
1.0
0.98
2.4
50th
1.2
0.77
2.3
2.9
1.9
1.5
3.2
75th
1.8
1.4
3.8
4.5
3.3
2.5
7.1
95th
3.4
2.3
8.6
6.6
5.8
8.1
12
Max
5.5
7.8
18
18
23
27
12
Dup Diet, Duplicate Diet; Dup Plate, Duplicate Plate
NC, Not calculated
Table A.35 Summary statistics for IMP measured in solid food, presented as both intake (ug/day) and concentration (ug/kg).
it
s 59
^^ 2.
Concentration
(ug/kg)
Study
CTEPP-OH
CTEPP (OH)
Method
Dup Diet/
Dup Plate
Dup Diet/
Dup Plate
Group
All
Home
Daycare
n
32
40
29
%Det
97
88
83
Mean
0.19
0.52
0.40
SD
0.17
0.54
0.29
GM
0.14
0.36
0.30
GSD
2.2
2.4
2.3
Min
O.024
0.12
0.13
25th
0.093
0.26
0.14
50th
0.12
0.33
0.35
75th
0.20
0.63
0.58
95th
0.58
1.6
0.90
Max
0.63
2.7
1.2
Dup Diet, Duplicate Diet; Dup Plate, Duplicate Plate
NC, Not calculated
185
-------
Hand Loadings
Table A.36 Summary statistics for chlorpyrifos hand loadings (ng/cm2).
Study
MNCPES
CTEPP (NC)
CTEPP (OH)
CPPAES
Group
Rinse
Home
Daycare
Home
Daycare
Rinse
Wipe
n
97
96
31
97
29
38
44
%Det
39
78
68
55
55
100
100
Mean
NC
0.053
0.023
0.18
0.036
2.8
0.32
SD
NC
0.11
0.022
1.5
0.11
3.1
0.29
GM
NC
0.020
0.013
0.011
0.010
1.6
0.19
GSD
NC
3.9
3.4
4.8
4.0
3.2
3.3
Min
0.07
O.007
O.007
O.007
0.007
0.09
0.016
25th
0.07
0.0082
O.007
O.007
0.007
0.74
0.87
50th
0.07
0.020
0.017
0.011
0.010
1.9
0.30
75th
0.094
0.046
0.036
0.029
0.021
3.7
0.42
95th
0.27
0.28
0.073
0.17
0.075
11
0.77
Max
3.1
0.74
0.077
15
0.58
18
1.5
NC, Not calculated
Table A.37 Summary statistics for diazinon hand loadings (ng/cm ).
Study
CTEPP (NC)
CTEPP (OH)
PET
DIYC
Group
Home
Daycare
Home
Daycare
Feasibility
All
n
96
31
97
29
15
13
%Det
36
55
31
31
100
100
Mean
NC
0.015
NC
NC
0.32
0.12
SD
NC
0.032
NC
NC
0.29
0.063
GM
NC
0.0069
NC
NC
0.19
0.092
GSD
NC
3.0
NC
NC
3.6
2.3
Min
0.005
O.005
O.005
O.005
O.005
0.005
25th
0.005
O.005
O.005
O.005
O.005
0.005
50th
0.005
0.0065
O.005
O.005
O.005
0.005
75th
0.011
0.014
0.0068
0.0071
O.005
0.005
95th
0.084
0.051
0.075
0.043
0.94
0.21
Max
1.6
0.17
3.8
0.093
0.94
0.21
NC, Not calculated
Table A.38 Summary statistics for c/s-permethrin hand loadings (ng/cm ).
Study
CTEPP (NC)
CTEPP (OH)
Group
Home
Daycare
Home
Daycare
n
96
31
97
29
%Det
86
94
88
79
Mean
0.92
0.17
0.14
0.15
SD
6.5
0.38
0.30
0.29
GM
0.071
0.067
0.039
0.034
GSD
6.7
3.9
4.9
6.5
Min
0.005
0.005
0.005
O.005
25th
0.026
0.035
0.017
0.010
50th
0.062
0.073
0.033
0.035
75th
0.26
0.15
0.095
0.14
95th
1.5
0.31
0.88
0.65
Max
64
2.2
2.1
1.4
NC, Not calculated
186
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Table A.39 Summary statistics for ^ram'-permethrin hand loadings (ng/cm ).
Study
CTEPP (NC)
CTEPP (OH)
Group
Home
Daycare
Home
Daycare
n
96
31
97
29
%Det
86
94
88
79
Mean
0.93
0.14
0.13
0.15
SD
6.8
0.38
0.34
0.33
GM
0.055
0.046
0.032
0.030
GSD
6.9
4.0
4.9
6.5
Min
0.005
0.005
O.005
O.005
25th
0.015
0.020
0.013
0.011
50th
0.049
0.036
0.027
0.028
75th
0.18
0.12
0.072
0.087
95th
1.3
0.26
0.77
0.83
Max
67
2.1
2.1
1.5
NC, Not calculated
Table A.40 Summary statistics for TCPy hand loadings (ng/cm ).
Study
CTEPP (NC)
CTEPP (OH)
Group
Home
Daycare
Home
Daycare
n
99
32
98
29
%Det
100
94
98
90
Mean
0.023
0.012
0.015
0.012
SD
0.022
0.0076
0.012
0.0075
GM
0.018
0.010
0.012
0.010
GSD
1.9
2.0
2.0
1.9
Min
0.0041
0.003
0.003
O.003
25th
0.012
0.0066
0.0079
0.0062
50th
0.019
0.010
0.012
0.011
75th
0.026
0.017
0.019
0.015
95th
0.054
0.029
0.033
0.030
Max
0.17
0.032
0.067
0.036
NC, Not calculated
Table A.41 Summary statistics for IMP hand loadings (ng/cm ).
Study
CTEPP (OH)
Group
Home
Daycare
n
98
29
%Det
49
31
Mean
NC
NC
SD
NC
NC
GM
NC
NC
GSD
NC
NC
Min
O.003
0.003
25th
O.003
0.003
50th
O.003
0.003
75th
0.0040
0.0031
95th
0.017
0.017
Max
0.064
0.043
NC, Not calculated
187
-------
Urinary Metabolite Concentrations
Table A.42 Summary statistics for TCPy measured in urine (ng/mL).
Study
NHEXAS-AZ
MNCPES
CTEPP-NC
CTEPP-OH
JAX
CPPAES
NHANES
Group
< 12 years
All
All
All
All
All
< 12 years
n
21
263
129
123
9
81
1245
%Det
100
92
98
100
100
93
90
Mean
12
9.2
7.5
5.9
11
8.0
4.7
SD
7.6
7.7
10
3.5
6.4
4.7
6.1
GM
9.3
6.6
5.5
4.9
9.1
6.4
2.6
GSD
2.2
2.3
2.1
1.9
2.1
2.1
3.2
Min
2.0
<1.4
<1.0
1.2
2.9
<1.0
<0.4
25th
5.7
4.0
3.8
3.1
7.5
4.5
1.3
50th
12
7.2
5.3
5.2
9.8
7.7
2.8
75th
14
12
8.4
7.8
15
11
6.0
95th
26
23
16
12
21
18
15
Max
30
45
100
15
21
20
64
Table A.43 Summary statistics for 3-PBA measured in urine (ng/mL).
Study
CTEPP-OH
JAX
NHANES
Group
All
All
< 12 years
n
126
9
679
%Det
68
100
79
Mean
0.81
19.6
1.4
SD
3.0
33
10
GM
0.38
3.9
0.36
GSD
2.6
7.5
3.7
Min
O.20
0.39
0.10
25th
O.20
0.76
0.13
50th
0.32
2.2
0.34
75th
0.69
29
0.78
95th
1.9
99
3.8
Max
34
99
254
Table A.44 Summary statistics for IMP measured in urine (ng/mL).
Study
PET
DIYC
NHANES
Group
All
All
< 12 years
n
30
41
1220
%Det
77
100
15
Mean
1.3
9.0
NC
SD
1.6
6.9
NC
GM
0.75
7.1
NC
GSD
2.8
2.0
NC
Min
O.22
1.7
0.7
25th
0.39
4.4
0.7
50th
0.62
7.1
0.7
75th
1.5
10
0.7
95th
5.5
27
3.0
Max
6.2
29
145
NC, Not calculated
188
-------
APPENDIX B: Individual Study Details
189
-------
National Human Exposure Assessment Survey in Arizona (NHEXAS-AZ)
Collaborators: University of Arizona, Battelle Memorial Institute, and the Illinois Institute of
Technology
Study Design:
Type: Observational exposure measurement study with probability-based sample
Location: Each of the 15 counties in Arizona
Monitoring period: December 1995 to March 1997
Study population: 176 households (this report only includes data from 21 households in
which the primary participants were children, ages 6-12)
Pesticide Use: Participants did not report use prior to the study
Monitoring Protocol:
Indoor and Outdoor air: 3-day integrated samples; Personal air: 1-day sample
Surface Dust Loading: Modified Hoover "Port-a-Power" vacuum, center and corner of
living room and bedroom; Window sill wipes
Soil: Yard surface soil composite sample
Beverages and solid food: 24-hour duplicate diet
Hand wipes: 4-mL IP A wipes of both hands
Urine: First morning void samples
Activities: Baseline and follow-up questionnaires, time-activity diary
Analytes (Pesticides):
o Two pesticides of primary interest (and metabolites), namely chlorpyrifos (TCPy)
and diazinon, and 14 secondary pesticides, including malathion (MDA) and
carbaryl (1-naphthol)
Key Outputs:
Occurrence, distributions, and determinants of total exposure to the general population
Geographic trends in multimedia exposure
Total exposures in minority and disadvantaged subsets of the population
190
-------
Minnesota Children's Pesticide Exposure Study (MNCPES)
Collaborators: RTI, EOHSI, University of Minnesota, and Minnesota Department of Health
Study Design:
Type: Observational exposure measurement study with probability-based sample
Location: Minneapolis/St. Paul (urban) and Goodhue and Rice counties (rural)
Monitoring period: Summer 1997
Study population: 102 children, ages 3-13
Pesticide Use: Households reporting a history of more frequent pesticide use were
oversampled
Monitoring Protocol:
Environmental samples:
o Personal, indoor, and outdoor air: Integrated samples, days 1-7 (outdoor air for
only 10% of urban homes)
o Surface dust loading: Wipe and press, 2 indoor locations (main play area and
family room), day 4
o Soil: Surface soil grab sample, day 4
o Beverages and solid food: Duplicate diet, 4-d composite, days 3-6
o Tap water: Grab sample (10% urban homes), day 4
Biological/Personal samples:
o Hand rinse, day 3
o Urine: First morning void samples (88%) 3 samples per child, days 3, 5, and 7
Activities:
o Baseline and follow-up questionnaires, time-activity diary
o Videotape (4-h, about 20 homes)
Analytes (Pesticides and PAHs):
o Pesticides: 4 Primary pesticides and metabolites, namely chlorpyrifos (TCPy),
atrazine (atrazine mercapturate), malathion (malathion dicarboxylic acid), and
diazinon, and 14 secondary pesticides
o PAHs: 13 PAHs including fluoranthene, phenanthrene, and pyrene
Key Outputs:
An "inverse" PK model to predict chlorpyrifos dose resulting both from specific pesticide
applications and from average low-level exposures
Distributions and correlations in environmental and biological media (Adgate et al,
2001; Clayton et al, 2003)
Evaluation of pathways of exposure
191
-------
Children's Total Exposure to Persistent Pesticides and Other Persistent Organic Pollutants
Study (CTEPP)
Collaborators: Battelle
Study Design:
Type: Observational exposure measurement study with probability-based sample in
homes and child care centers
Location: North Carolina (NC) and Ohio (OH)
Monitoring period: NC (July 2000 to March 2001); OH (April 2001 to November 2001)
Study population: 257 children, ages 18 months to five years, and their primary adult
caregivers (NC = 130 children, 130 homes, 13 day care centers; OH =127 children; 127
homes, 16 day care centers)
Pesticide use: Use during previous seven days were reported by a subset (n=38) of
families in their homes
Monitoring Protocol:
Sampling times: Samples collected over a 48-hr period at a home and/or daycare center:
Samples/data collected: Soil, outdoor air, indoor air, indoor floor dust, hand wipe, liquid
food, solid food, urine
Supplemental information:
o Recruitment survey, house/building characteristics survey, pre- and post monitoring
questionnaires, activity and food diaries
o In addition, 20% of the participants from OH were videotaped about 2 hours at their
homes
o Additional samples were collected if a pesticide was reported by the participant as
having been applied indoors or outdoors at a home or daycare center within 7 days of
previously scheduled field sampling or during the 48-hr monitoring period (hard floor
surface wipe, food preparation surface wipe, and transferable residue)
Analytes of interest: Chlorpyrifos, diazinon, and c/W^ram'-permethrin
Key Outputs:
Pesticide distributions in microenvironments where children spend time
Transfer of pesticides from microenvironmental media to child and factors that affect
transfer
Evaluation of pathways of exposure
Evaluation of important factors the affect exposure
192
-------
First National Environmental Health Survey of Child Care Centers (CCC)
Collaborators: HUD, CPSC (US Department of Housing and Urban Development, US
Consumer Product Safety Commission)
Study Design:
Type: Observational study with probability-based sample of licensed child care centers
Location: Nationwide
Monitoring period: August 2001 to October 2001
Study population: 168 child care centers; no children or adults participated in the study
Pesticide use: Child care center directors reported on the professional or center staff
applications during the previous 12 months
Monitoring Protocol:
One time visit by field technicians to each child care center
Samples collected: Soil, surface wipes, transferable residues (surface press)
Analytes: Current-use pesticides - organophosphates and pyrethroids
Key Outputs:
Data relating to pesticide use practices in child care centers across the US
Characterization of spatial distribution and magnitude of pesticide concentrations on
surfaces in a sample of U.S. child care centers
193
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Biological and Environmental Monitoring for Organophosphate and Pyrethroid Pesticide
Exposures in Children Living in Jacksonville, Florida (JAX)
Collaborators: CDC (Centers for Disease Control and Prevention), DCHD (Duval County
Health Department)
Study Design:
Type: Observational pilot exposure measurement study
Location: Jacksonville, Florida (Duval County)
Monitoring period: August to October 2001
Study population: Nine children 4-6 years of age
Pesticide use: Participants report recent pesticide use in the residences
Monitoring Protocol:
Sampling times: One-time sample collection with 24-hour air samples
Samples collected:
o Surface wipe
o Indoor/outdoor air
o Duplicate diet
o Transferable residues
o Cotton garments
o Urine
Questionnaires:
o Pesticide screening inventory
o Time activity diary
Analytes: OP, pyrethroid pesticides, metabolites in urine
Key Outputs:
The CDC component of the study determined the distribution of urinary metabolite levels
of organophosphate and pyrethroid pesticides in a group of 4-6 year old children living in
the greater Jacksonville, Florida area
The DCHD component of the study evaluated the use of screening wipes and pesticide
inventories to identify homes with potentially elevated pesticide levels and to identify
potential household sources for pesticides
The EPA nine-home study was performed to evaluate methods for aggregate exposure
measurements, to determine whether environmental measures of pesticide exposure are
correlated with biological samples for a sub-sample of homes using pesticide inventories
and screening measurements, to evaluate if information collected from pesticide
screening inventories about pesticides used in the home correlates with environmental
measures found in the same homes, and to evaluate pathways of exposure and the
important factors that affect exposure
194
-------
Center for the Health Assessment of Mothers and Children of Salinas Quantitative
Exposure Assessment Study (CHAMACOS)
Collaborator: University of California at Berkeley
Study Design:
Type: Observational pilot exposure measurement study
Location: Salinas, California
Monitoring period: June 2002 to October 2002
Study population: Twenty children ages 5 to 35 months old, 10 female, 10 male
Pesticide use: Incidental for farmworker children
Monitoring Protocol:
Sampling times: 24-hour monitoring
Samples collected:
o Indoor and outdoor air
o House dust
o Transferable residues from floors (surface wipes and press samples)
o Transferable residues from toys (surface wipes)
o Cotton union suits and socks
o Urine
Activities
o Videotaping
o Time-activity diary
Analytes: acephate, azinphos methyl, bifenthrin, chlorpyrifos, chlorpyrifos oxon, cis-
allethrin, trans-aftethrin, c/'s-permethrin, /ram'-permethrin, cyfluthrin (I, II, III, IV),
cypermethrin ( I, II, II, IV), dacthal, deltamethrin (I, II), diazinon, dimethoate,
esfenvalerate, fonofos, iprodione, /awfo/a-cyhalothrin, malathion, methidathion, naled,
p,p'-DDE, p,p'-DDT, phosmet, resmethrin, sumithrin, tetramethrin (I, II), vincloziline
Key Outputs:
Evaluation of methods for aggregate exposure measurements
Pesticide distributions in microenvironments where children spend time
Transfer of pesticides from microenvironmental media to child and factors that affect
transfer
Evaluation of pathways of exposure and important factors that affect exposure
195
-------
Children's Pesticide Post-Application Exposure Study (CPPAES)
Collaborator: EOHSI (Environmental and Occupational Health Sciences Institute)
Study Design:
Type: Observational pilot exposure measurement study
Location: Urban New Jersey
Monitoring period: April 1999 to March 2001
Study population: 10 homes; children 2-5 years of age
Pesticide use: Crack and crevice application of chlorpyrifos was applied by a professional
applicator in these homes
Monitoring Protocol:
Sampling times: 1 day prior to application, 1, 2, 3, 5, 7, 9, and 11 days after application
Samples collected:
o All sampling days: indoor air, deposition coupons, surface samples (LWW), toys,
hand wipes, urine, air exchange rate, time activity diary
o Additional day 2 samples - surface wipes, hand wipes, dermal wipes, cotton
garments, videotaping
Analyte: Chlorpyrifos, TCPy in urine
Key Output:
Pesticides distributions in microenvironments where children spend time
Transfer of pesticide from microenvironmental media to child and factors that affect
transfer
Evaluation of pathways of exposure
Evaluation of important factors that affect exposure
196
-------
The Distribution of Chlorpyrifos Following a Crack and Crevice Type Application in the
US EPA Indoor Air Quality Research Test House (Test House)
Collaborator: National Risk Management Research Laboratory
Study Design:
Type: Field laboratory (Indoor Air Quality Research Test House)
Location: Gary, NC
Monitoring period: 3 weeks during November 2000
Study population: Single residential house; no occupants in the test house
Pesticide use: Chlorpyrifos, EC formulation, crack and crevice application in kitchen area
(floor and cabinetry)
Monitoring Protocol:
Sampling intervals: Pre, 1, 3, 7, 14 and 21 days post application
Sample types:
o Application formulation concentration
o Air (kitchen, den and master bedroom)
o PUF-skin roller (den and kitchen)
o Carpet sections (den and master bedroom)
o 10-min CIS surface press (den carpet and kitchen vinyl floor), wipes (kitchen
floor and counter)
Analyte: Chlorpyrifos
Key Outputs:
Translocation and exposure pathways
Inputs to algorithms and SHEDS
Temporal and spatial variability over sampling period
197
-------
A Pilot Study Examining Translocation Pathways Following a Granular Application of
Diazinon to Residential Lawns (PET)
Collaborators: None
Study Design:
Preceded by a 1-home feasibility study
Type: Observational pilot exposure measurement study residential homes
Location: 50 mile radius of Durham, NC
Monitoring period: Ten days in Spring 2001
Study population: 6 homes, 1 child and care giver (typically mother)
Pesticide use: Homeowner applied diazinon, granular formulation, residential lawns (turf)
Monitoring Protocol:
Sampling intervals: Pre, 1, 2, 4 and 8 days post application
Sample types:
o Application formulation concentration
o Air (living room and child's bedroom)
o PUF roller (lawn and indoor floor)
o Soil
o Entryway doormat
o HVS3
o Cotton gloves (technician and child)
o Urine (adult and child)
o Dog fur clippings
o Dog paw wipes
o Dog blood
o Videography (15-min)
Key Outputs:
Methods evaluation
Translocation and exposure pathways
Decay rates over sampling period
Inputs to algorithms and SHEDS
198
-------
Dietary Intake of Young Children (DIYC)
Collaborator: RTI
Study Design:
Type: Observational pilot exposure measurement study
Location: Raleigh, NC area
Monitoring period: November 1999 to January 2000
Study population: 3 homes; children 1-3 years old
Pesticide use: Diazinon applications reported by homeowner - commercial crack and
crevice (2 homes) or applied by resident (1 home)
Monitoring Protocol:
Sampling times: Pre-application to 8 days post-application (7 visits total)
Samples collected:
o Indoor and outdoor air
o Surface wipes (isopropanol)
o Entry wipe
o PUF roller
o Surface press
o Hand wipes
o Food press
o Food samples
o Urine
Analyte: Diazinon
Key Outputs:
Evaluation of methods to measure excess dietary exposures that occur from activities by
young children during eating
Children's dietary intake model accurately represents total dietary exposures of children
Model predictions are closest to measured results with the highest measured
environmental diazinon concentrations
Refinements for transfer and activity parameters within model are needed
Categories of transfers and activities for highly exposed vs. less exposed are needed
199
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Characterizing Pesticide Residue Transfer Efficiencies (Transfer)
Collaborator: Battelle
Study Design:
Type: Controlled laboratory study
Objective: Evaluate parameters that affect residue transfer from surface-to-skin, skin-to-
other objects, skin-to-mouth, and object-to-mouth
Monitoring period: not applicable
Study population: not applicable
Pesticide use: Nontoxic fluorescent tracers used as surrogates for pesticides
Monitoring Protocol:
Conduct study using nontoxic fluorescent tracers as a surrogate for pesticide residues
Apply fluorescent tracer as a residue at levels typical of residential pesticide applications
to surfaces of interest
Conduct controlled transfer experiments varying parameters in a systematic fashion
Hand Contact Trials
o Systematically varied six parameters
o Repetitive contacts with contaminated surface
Transfer off skin
o Hand to clean surface
o Hand to washing solution
o Hand to mouth
Mouthing Trials
o Varied 5 parameters
o Simulated mouthing using saliva moistened PUF
o Measured mass of tracer transferred and estimated contact surface area using
video imaging techniques
Conduct laboratory evaluations to relate transfer of tracer to transfer of pesticides
Key Outputs:
Transfer efficiency data
Information on type of microactivity data needed to estimate dermal exposure
Inputs for multipathway exposure models
200
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Feasibility of Macroactivity Approach to Assess Dermal Exposure (Daycare)
Collaborator: RTI
Study Design:
Type: Observational pilot exposure measurement study
Location: North Carolina
Monitoring period: Three occasions, twice per occasion
Study population: Infants and toddlers at daycare centers
Pesticide use: Professional crack and crevice applications as contracted by the daycare
center
Monitoring Protocol:
Identify up to 9 daycare centers with previously established contracts for routine monthly
pesticide applications
In each daycare, conduct screening sampling to evaluate the distribution of transferable
pesticide residue on floor surfaces in the area where children spend the most time
Select one daycare for intensive measurements
Children from different age groups volunteered to wear full-body cotton bodysuits for
short time periods
Conduct surface sampling and videotaping of activities simultaneously with dermal
loading sampling
Calculate dermal transfer coefficients
Key Outputs:
Pesticide distributions in nine daycare centers
Verified protocol for collecting aggregate surface measurement
Verified protocol for collecting transfer coefficients
Dermal transfer coefficients developed with children (to evaluate default assumptions
usedinOPP'sSOPs)
201
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Food Transfer Studies, also known as Press Evaluation Studies (Food)
Collaborator: RTI
Study Design:
Type: Controlled laboratory study
Location: NERL Cincinnati
Study period: Not applicable
Study population: Not applicable
Pesticide use: Organophosphate, pyrethroid, and pyrazole insecticides on various
household surfaces
Monitoring Protocol:
Surfaces:
o Surface Treatment: A customized spray chamber was used to spray Pesticide
Spray Solution (PSS) onto the ceramic tiles
o Surface Drying: Following spraying, each ceramic tile was transferred to a glove
box where it was air dried for an hour at constant temperature and humidity
o Surface Wipes: Pesticide transfer to foods were compared to the pesticides
removed using surface wipes (isopropanol moistened gauze pads), which were
wiped across the ceramic tile in both the horizontal and vertical direction
Food Items:
o Moisture Content: Moisture (%) content measured with a Denver Instrument IR-
30 moisture meter
o Fat Content: Fate (%) content determined from each food's Nutrition Facts label;
% fat = [total fat (g) / food serving size (g)] *100
o Food Items: Pesticide transfer efficiencies were measured for three different
foods, with standardized surface contact area; the foods were Fruit Roll-Ups
Blastin' Berry Hot Colorsฎ (Betty Crockerฎ), thinly sliced bologna (made with
chicken & pork), and Red Delicious apple slices
Transfer Efficiency (TE): TE is defined as the amount of pesticide recovered from the
food item divided by the pesticide concentration or loading level
Analytes: Malathion, Chlorpyrifos, Fipronil, Permethrin, Cyfluthrin, Cypermethrin,
Deltamethrin
Key Outputs:
Determine the extent of pesticide transfer from household surfaces to foods
Evaluate factors that have been identified as important, including surface type, duration
of contact, surface loading, and contact pressure (applied force or weight per area)
Compared surface wipes using cotton gauze pads with the pesticide transfer to the foods
202
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March 2007
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