United States Environmental Protection Agency	Office of Research and Development

National Exposure Research Laboratory
Research Abstract

Government Performance Results Act (GPRA) Goal 3
Annual Performance Measure 253

Significant Research Findings:

Understanding Exposure Factors that may Lead to High-Level,
Short-Term Exposures of Children to Pesticides

Scientific	The U.S. Environmental Protection Agency has pledged to increase its efforts to

Problem and	provide a safe and healthy environment for children. The Food Quality Protection

Policy Issues	Act of 1996 (FQPA), for example, requires that children's risks to pesticide

exposures be considered during the tolerance-setting process. FQPA requires
exposure assessments to be conducted for all pesticide sources. It also requires
that assessments use high quality and high quantity exposure data or models based
on exposure factors generated from existing, reliable data. Currently, data on
children's exposures and activities are insufficient to support quantitative exposure
assessments. Rather, they rely heavily on major default assumptions as substitutes
for missing information. An initial assessment of critical exposure pathways and
factors for assessing children's residential exposures to pesticides indicated that
data gaps existed in four areas: pesticide use patterns, spatial and temporal
distributions of pesticides in residential dwellings, dermal exposure assessment,
and dietary ingestion to include indirect ingestion due to the food handling by
children. Studies are needed to obtain a better understanding of the factors
impacting children's exposure to pesticides and to generate data for homes and
daycare centers.

The objective of this program was to identify the pesticides, pesticide use patterns,
exposure pathways, and activities that represent the highest potential exposures to
children and the factors that influence these exposures. To address these
objectives, a set of targeted laboratory and pilot field studies were conducted to
collect data to address one or more of the four focus areas of research. Pesticide
concentrations were measured indoors and outdoors at homes and daycare centers
for children 8 months to 5 years of age; laboratory and small field studies were
conducted to develop dermal transfer efficiency data and transfer coefficients;
children's activity pattern data were collected; and protocols for measuring and
assessing aggregate exposures were developed and tested in the field.

Children's exposures to pesticides and the factors impacting exposure have been
evaluated in laboratory and field measurement studies. Results of these
measurements have specifically addressed the following:

Development and evaluation of a quantitative video fluorescent tracer for

Research
Approach

Results and
Impact


-------
measuring transfer of pesticide residues from surfaces to hands with
repeated contacts.

Characterization of pesticide residue transfer efficiencies using a
fluorescent tracer.

Evaluation of pesticide occurrence and distributions in daycare centers.
Measurements of pesticide occurrence and surface residue concentrations
in homes.

Estimates of aggregate exposures of children to pesticides in residences.
Evaluation of the macroactivity approach for assessing children's dermal
exposure.

Measurements of transfer coefficients for estimating dermal and indirect
ingestion exposure.

Evaluation of human exposure to pet-borne diazinon residues following
lawn application.

Results of these studies will be used by EPA's Office of Pesticide Programs and
National Center for Environmental Assessment, as well as the pesticide industry,
to better understand the important factors for children's exposures . Data from
these studies can be used to replace and/or refine default assumptions, thereby
reducing the uncertainty in the risk assessments for pesticides and other persistent
pollutants.

The children's exposure measurements research in support of FQPA are being
conducted by EPA's National Exposure Research Laboratory, with support from
the Research Triangle Institute and the Battelle Memorial Institute under contract
to the EPA. Additionally, work is being performed in collaboration with the
Centers for Disease Control and Prevention, the Department of Housing and
Urban Development, the Consumer Product Safety Commission, and the Duval
County Health Department located in Jacksonville, FL.

Examples of publications from this research program include the following:

E.A. Cohen Hubal, L.S. Sheldon, J.M. Burke, T.R. McCurdy, M.R. Berry, M.L. Rigas, V.G.
Zartarian and N.C.G. Freeman. (2000) Children's exposure assessment: A review of factors
influencing children's exposure, and the data available to characterize and assess that
exposure. Environmental Health Perspectives. 108(6): 475-486.

E.A. Cohen Hubal, L.S. Sheldon, M.J. Zufall, J.M. Burke, K.W. Thomas. (2000) The challenge
of assessing children's residential exposure to pesticides. Journal of Exposure Analysis and
Environmental Epidemiology, 10(6), Part 2: 638-649.

Morgan, M., D.M. Stout II, and N. Wilson. (2001) A feasibility study of the potential for
human exposure to pet-borne diazinon residues following lawn applications. Bulletin of
Environmental Contamination and Toxicology 66(3):295-300.

Tulve, N.S., J.C. Suggs, T. McCurdy, E.A. Cohen Hubal, and J. Moya. (July, 2002) Frequency
of mouthing behavior in young children. Journal of Exposure Analysis and Environmental
Epidemiology 12(4):259-264.

Stout, D.M. II and M.A. Mason. (2003) The distribution of chlorpyrifos following a crack and
crevice type application in the U.S. EPA indoor air quality research house. Indoor Air (in
press).

Rohrer, C.A., T.E. Hieber, L.J. Melnyk, and M.R. Berry (2003). Transfer efficiencies of
pesticides from household flooring surfaces to foods. Journal of Exposure Analysis and
Environmental Epidemiology (in press).

Research
Collaboration and
Research
Products


-------
Melnyk, L.J., C.E. Bernard, J.N. Morgan, and M.R. Berry (2003) Excess exposures of young
children eating in contaminated environments. Environmental Health Perspectives
(submitted).

E.A. Cohen Hubal, J.C. Suggs, M.G. Nishioka, W.A. Ivancic (2003). Characterizing pesticide
residue transfer efficiencies using a fluorescent tracer imaging technique. Journal of Exposure
Analysis and Environmental Epidemiology (submitted).

Ivancic W.A., M.G. Nishioka, R.H. Barnes, and E.A. Cohen Hubal. (2003). Development and
evaluation of a quantitative video fluorescence imaging system and fluorescent tracer for
measuring transfer of pesticide residues from surfaces to hands with repeated contacts.

Annals of Occupational Hygiene (submitted).

Future Research Results of these studies have been used to design a large aggregate exposure study
of infant's and toddler's exposure to pesticides and persistent organic chemicals in
their homes, as described in the research abstract for the "Design for a Field Study
to Evaluate Protocols for Obtaining Reliable Data on Children's Exposure to
Pesticides," (FY03 APM 244). The study has been designed to develop reliable
protocols for estimating exposure for all relevant pathways and children's age
groups, develop critical inputs for models used in the regulatory process, develop
exposure factors as a function of age/developmental stage, evaluate age and
development-related differences in young children's exposures, determine the
impact of children's activities at different development ages on exposure, and
develop a core data set of high quality exposure concentration measurements. The
proposed longitudinal field study will be implemented over the next three years.


-------
Contacts for	Questions and inquiries can be directed to the principal investigators:

Additional	Nicolle Tulve, Ph.D.

Information	jj.S. EPA, Office of Research and Development

National Exposure Research Laboratory
MD E205-04

Research Triangle Park, NC, 27711
Phone: 919-541-1077
E-mail: tulve.nicolle@,epa.gov

Roy Fortmann, Ph.D.

U.S. EPA, Office of Research and Development
National Exposure Research Laboratory
MD E205-04

Research Triangle Park, NC, 27711

Phone: 919-541-1021

E-mail: fortmann.rov@,epa.gov

Linda Sheldon, Ph.D.

U.S. EPA, Office of Research and Development
National Exposure Research Laboratory
MD E205-01

Research Triangle Park, NC, 27711

Phone: 919-541-2205

E-mail: sheldon.linda@,epa.gov

Lisa Melnyk, Ph.D.

U.S. EPA, Office of Research and Development
National Exposure Research Laboratory
Mail Code 564
Cincinnati, OH, 45268
Phone:513-569-7494
E-mail: melnvk.lisa@,epa.gov

Extramural federal funding for this research was administered under EPA
contracts 68-D-99011 (Battelle Memorial Institute) and 68-D-99-012 (Research
Triangle Institute).


-------