U.S. EPA Office of Research
and Development's Science
To Achieve Results (STAR)
Research in Progress
Vol.1 Issue 1 Oct. 1997 A product of the National Center for Environmental Research and Quality Assurance
CHILDREN'S EXPOSURE
TO PESTICIDES
Children face an array of complex envi-
ronmental health threats. They are more
susceptible than adults to harmful health
effects from some chemicals, including
pesticides, because of their activities, and
because their small, developing bodies are
more sensitive to toxic stress. Because of
this, EPA has made a special commitment
to ensure that all children are protected
against harm from pesticides and other
chemicals.
The exposure of children to pesticides
around their homes, and in public areas such
as schools, playgrounds or day care centers,
has been recognized as an important and
inadequately understood problem. In con-
ducting a 1993 review of potential risks due to
pesticides in the diets of children, the National
Research Council (NRC) determined that
children, including infants, might be at greater
risk than adults from harmful effects that
pesticides can cause. Potential effects of
pesticides on people of any age include cen-
tral nervous system damage, cancer and
respiratory illness. In addition, based on the
NRC report and other studies, EPA has taken
steps to ensure that necessary additional
testing will be undertaken to assess any special
vulnerability of children to pesticide effects on
development, the immune system, the repro-
ductive system and the visual system.
Several factors may contribute to increased
vulnerability of children to pesticides. The rapid
development and immaturity of their body or-
gans and systems makes them more susceptible
than adults to toxic effects of any chemicals.
For example, children's tissues may absorb chemi-
cals more readily and be less able to break them
down, and their organ systems may be less effec-
tive at passing some chemicals out of the body.
The protection of children's health is one of the highest priorities
of the Environmental Protection Agency
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In addition, the amount of expo-
sure to pesticides is quite different
for children than for adults, be-
cause of differences in physical en-
vironment, activities and diet. The
NRC study considered all of these
factors, and concluded that differ-
ences in exposure between adults
and children were more likely to
account for differences in risk than
were age-related differences in tox-
icity. Based on this, the NRC
strongly recommended research
to better understand the extent to
which children are exposed to pes-
ticides.
Responding to this need, EPA's
major external research program,
Science to Achieve Results (the
"STAR program") allocated funds
in fiscal year 1996 to research the
most urgent issues regarding ex-
posure of children to pesticides.
The grants were awarded for three
year time periods. Resulting find-
ings, along with the results of some
related research under other com-
ponents of the STAR program, will
provide a far more comprehensive
understanding of children's pesti-
cide exposures. Research currently
underway in these STAR projects
is summarized in this report. Re-
sults will be presented in future
reports over the coming one to
three years, as findings are com-
pleted and peer reviewed.
Settings of Special Concern
Greater exposures of children to
pesticides than is typical for the
general population may occur in
some settings. In some cases, but
not all cases, these settings involve
a disproportionate number of
people of disadvantaged socio-
economic groups, such as migrant
agricultural workers, or residents of
older urban public housing com-
plexes. Settings of particular con-
cern including the following:
• Urban homes subjected to fre-
quent applications of insecti-
cides and/or rodenticides;
• Homes of agricultural workers, or
other rural homes, where chil-
dren may be exposed to con-
taminated clothing or skin of
adults, or to agricultural chemi-
cals coming into the home in
other ways;
Institutional settings such as day
care centers in which infants
and very young children have a
high degree of exposure to car-
pets and other surfaces that
may be treated with commer-
cial pesticide applications; and
Homes with pets treated with pes-
ticides to control fleas or other
pests, or that track in pesticides
from outside the home.
Children's Behavior
Behavioral factors that can make
children, including infants, more
likely to be exposed to pesticides
include the following:
crawling, sitting and lying on con-
taminated surfaces such as car-
pets, floors and lawns;
transfers of contaminants from
objects or surfaces through di-
rectly mouthing hands, ob-
jects or plants, and ingesting
dust or soil,
greater time spent in household
gardens, or in private or pub-
lic play areas treated with pes-
ticides.
General Information: The Environmental Protection Agency's STAR Research Program
Grants described in this report are part of EPA's Science to Achieve Results (STAR) program, a major
research initiative designed to improve the quality of scientific information available to support environ-
mental decision making. The STAR program is managed by EPA's Office of Research and Development
(ORD) out of the National Center for Environmental Research and Quality Assurance. The program is
expected to fund approximately 200 new grants every year, with the typical grant lasting three years.
Funding levels vary from $75,000 to $500,000 per year, with FY 1997 funding levels expected to reach
over $100 million for grants to individual principal investigators or groups of investigators. Additional
STAR funds are provided for a number of Research Centers specializing in scientific areas of particular
concern to EPA, and for a fellowship program supporting graduate students conducting environmental
research.
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STAR Research Focusing on Children's Exposures to Pesticides
because they are widely used, and
they can cause neurotoxic effects
with high exposures.
Exposures of Children to Pets' Flea
Control Chemicals. Complete in-
formation is not currently available
on how much pesticide exposure
children may experience from pets
treated with flea control products.
These products often contain or-
STAR research projects are collecting data on children's behavior and environment that will be used to
assess exposure and risk. The extensive environmental and biological sampling proposed in the field
studies will allow further refinement in sampling design, field study protocols, analytical techniques,
human activity databases, and data interpretation for exposure assessments. The studies are looking at all
types of exposure (touching, eating, crawling, etc.), and at seasonal and locational differences. When
considered along with improved information on differences in toxicities of pesticides between children and
adults, the improved exposure information will give a much more complete picture of the differences in
overall pesticide risks. This will support regulations and public education efforts that are more fully protec-
tive of children, for example through revised use restrictions and labeling requirements, and improved
training and public information materials.
Total Exposure Assessments
Three research projects are fo-
cusing on children's exposures in
urban, suburban and suburban
settings. A study led by the Uni-
versity of Minnesota (1) is assess-
ing amounts of the principal types
of pesticide that children encoun-
ter through all "exposure routes"
(for example: touching surfaces
in homes, schools and day care
centers; from outdoor exposures;
secondary contamina-
tion from family mem-
bers; and contamination
of foods or drinks.) The
study will compare ex-
posures in three types of
neighborhood: central
city, suburban, and rural.
In Yuma County, Ari-
zona, investigators from
the University of
Arizonia (2) are assess-
ing exposures of the chil-
dren of seasonal and mi-
grant laborers to agricul-
tural pesticides. These
families frequently live near the
edges of fields. In eastern and
western Washington state, the
University of Washington (3) is
assessing, on a comprehensive sea-
sonal basis, children's exposures to
organophosphorus pesticides.
These are of particular concern
ganophosphorus compounds,
which are more readily absored
into the body through ingestion,
or hand-to mouth contact, than
through skin contact alone. This
study will help to determine
whether there are greater expo-
sures, and thus potential for
greater risks, to children than
adults, due to greater likelihood of
exposure through fur contact with
skin, transfers from hands to
mouth, etc.. A grant was awarded
in FY 1996 to researchers at Mis-
sissippi State University (4), who
are determining how much active
ingredient from the most common
types of flea product is transferred
to children through the kinds of
interactions that can occur with
family dogs.
Other Related STAR
Research
In addition to the com-
ponent of the STAR pro-
gram exclusively focused
on children and pesticides,
several projects funded
through other compo-
nents of the STAR program
will also contribute infor-
mation about potential
pesticide exposure or ef-
fects in children.
Potential Chromosome
Damage in Male Pesticide Appli-
cators. In the "Environmental
Health" category of STAR research
studies, a grant has been awarded
to the University of California,
Riverside (5), for some relevant
laboratory studies of cell cultures,
and for field studies of male pesti-
cide applicators. The study will
assess whether laboratory expo-
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sures of human cells to cancer
causing chemicals, or exposures of
men to pesticides in agricultural
work settings, are associated with
chromosome damage in human
cells, including sperm or lymphatic
system cells. Findings of chromo-
some damage would not directly
demonstrate what health or fertil-
ity impacts might be resulting in
exposed men or their children. If
chromosome changes were found
in the laboratory studies with hu-
man cells, and were confirmed in
studies of exposed people (for ex-
ample through "exposure marker"
techniques), it would suggest an
important need for comprehensive
health effects studies, to determine
what relationships there are be-
tween specific pesticide exposures,
chromosome effects, and health
effects in adults and their children.
Potential Endocrine Disrupter Ef-
fects due to Maternal Exposure
in Rats. Wildlife observations have
found a number of initially unex-
plained incidents of reproductive
disorders, deformities or other
health effects related to the ani-
mals' endocrine (hormone) sys-
tems. Subsequent studies have
found that some of these effects
were caused by toxic chemicals in
the environment, some of them
pesticides. Concern has been
raised that similar effects may oc-
cur in humans exposed to endo-
crine disrupter chemicals, includ-
ing some pesticides and their
breakdown products. The STAR
program includes a research area
devoted to laboratory and field
studies of potential endocrine
disrupter effects relevant to people
or wildlife.
One of the studies is looking at
a pesticide that could pose risks to
children. In this case the concern
is based on potential exposures of
mothers, rather than exposure of
children due to their own activi-
ties. Mississippi State University
(6) is using laboratory studies to
assess the effects of the insecticide
methoxychlor, as well as the indus-
trial chemicals PCBs. They are test-
ing the hypothesis that exposures
of female rats to a breakdown
product of methoxychlor may re-
sult in exposures of the young dur-
ing pregnancy or while
nursing, thereby causing
abnormal sex hormone
levels and developmental
abnormalities in the
young as they mature. Be-
cause exposures tested will
include low levels that
could occur in the envi-
ronment, findings of
harmful effects in rats
would indicate a possibil-
ity of risks to humans due
to maternal exposures.
This would indicate a need
for more work to thor-
oughly assess possible hu-
man exposure, and for
consideration of the new
information in regulating
insecticide uses.
Households' Choices in
Chemical Uses for Gar-
dening and Landscap-
ing. One of the less well
known aspects of pesticide
exposure is the ways that
families use pesticides in
home gardening, and the
information people take
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into account in making
choices about home chemi-
cal use. Under a component
of the STAR program devoted
to socio-economic research,
investigators at the Univer-
sity of California, Berkeley
(7), are studying factors that
affect the choices families
make in garden landscaping
and chemical use. The study
will assess which types of gar-
den and landscape are cho-
sen based on maintenance
time and costs, and whether
having children in the house-
hold affects uses of garden
pesticides. Results will be use-
ful in evaluting regulatory, la-
beling, and public education
strategies for reducing risks.
Related Research of EPA's In-House Laboratories
Related research relevant to
children's exposures to pesticides
is also conducted directly in the
laboratories of EPA's Office of Re-
search and Development (ORD).
The Agency's historical work on
pesticides and human develop-
ment was summarized in a 1995
EPA report, "Pesticides in the Diets
of Infants and Children". EPA's
principal current research in this
area is through the "National Hu-
man Exposure Assessment" pro-
gram (NHEXAS), being performed
by EPA/ORD, academic and other
research institutions, and other fed-
eral agencies. Also, EPA is conduct-
ing special regional studies
(complementing programs associ-
ated with the North American Free
Trade Agreement), assessing
children's exposures to pesticides
in U.S.-Mexican border areas.
There is on-going coordination be-
tween the STAR research projects
conducted by external scientists
and EPA's in-house research. In
addition, STAR researchers and EPA
researchers are coordinating with
research by state health agencies.
Find Out More About the STAR Research Program
Further information on the STAR program is available from
the following sources:
Internet Website, managed by the ORD National Center for Envi-
ronmental Research and Quality Assurance (NCERQA):
URL: http://www.epa.gov/ncerqa
Mailing Address:
Office of Research and Development
National Center for Environmental Research and Quality
Assurance
Office of the Director (8701 R)
401 M Street
Washington, DC 20460
Or, use the Telephone Hotline, 1-800-490-9194, to leave mes-
sages and receive auto faxes of announcements.
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Specific Research Projects Described in This Report
1) Measuring and Apportion-
ing Children's Exposure to Pes-
ticides in Urban, Suburban,
and Rural Communities.
School of Public Health,
University of Minnesota.
2) Exposure of Children to Pes-
ticides in Yum a County. £
Arizona College of Medi- **
cine, University of Arizona.
3) Total Organophosphorus
(Op) Pesticide Exposure among
Children in Urban and Rural
Environments. Department
of Environmental Health,
University of Washington.
4) Assessing Levels of Organo-
phosphorus Insecticides Which
Could Expose Children from
Pets Treated with Flea Control
Insecticides. College of Vet-
erinary Medicine, Missis-
sippi State University.
5) Development of Molecular
Cytogenetic Techniques to De-
tect Chromosomal Aberrations
in Human Sperm and Lympho-
cytes. University of Califor-
nia, Riverside.
6) Biochemical and Reproduc-
tive Effects of Gestational/Lac-
tational Exposure to PCB's with
Respect to Endogenous Sex Ste-
roids and the Proestrogen,
Methoxychlor. Mississippi
State University.
7) The Microeconomy of
Chemical Use on Residential
Landscapes. University of
California, Berkeley.
United States
Environmental Protection Agency
Mail Code 8701R
Washington, D.C. 20460
Offical Business
Penalty for Private Use
$300
EPA/600/F-97/020
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