Impact/Purpose:

The purpose of this research is to reduce uncertainties in exposure assessments of young children by improving EPA's ability to measure exposures in the context of aggregate and cumulative exposure assessments. The general objective of this research is to support FQPA children's exposure assessment efforts by improving procedures and reducing uncertainty in measurements for dietary exposure of young children, a critically needed area for improved risk assessment. Specifically, this research will evaluate a protocol and companion model for measuring or otherwise assessing the combined dietary intake of a young child as influenced by pesticides, or other environmental contaminants, which contaminate their foods during the eating process (indirect ingestion exposure). This research will continue to develop the important factors which are needed to characterize excess intake of pesticides by young children. Specifically, the research will measure pesticide surface transfer efficiencies for food contacts with surfaces and eating activity patterns of young children that define the frequency of contacts with contaminated surfaces. A series of reports/products are anticipated by the end of FY05.

Description:

Dietary exposure research supports the requirements of the Food Quality Protection Act (FQPA) of 1996 by improving methods of aggregate and cumulative exposure assessments for children. The goal of this research is to reduce the level of uncertainty in assessing the dietary pathway relative to other pathways. This will improve NERL's ability to measure dietary intake and contributions from indirect ingestion. Excess contamination due to surface-to-food and surface-to-hand-to-food contacts for young children occurs during their eating processes. This task describes research efforts in the areas of dietary measurement protocol improvements, field measurement evaluations, and improved modeling of dietary exposure to assess these excess exposures. Specifically, research will be conducted to further test and evaluate a protocol and companion model for measuring or otherwise assessing the combined dietary intake of a young child as influenced by pesticides, or other environmental contaminants, which contaminate their foods during the eating process (indirect ingestion exposure). The interactions of food with environmental media, such as hands, floors and other contaminated surfaces, will be characterized. An understanding of the child's eating activities will be developed in order to accurately measure and efficiently model indirect ingestion exposures of young children. A complete and valid model with protocols for collecting appropriate samples for model parameter input will be finalized and used in NERL multimedia/multipathway human exposure studies to evaluate total dietary exposure including indirect ingestion exposures.

Record Details:

Record Type:PROJECT

Start Date:07/01/1998

Projected Completion Date:09/01/2005

OMB Category:Other

Record ID: 29212

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Project Information:

Progress :Two major projects are addressed in this task; characterizing children's excess dietary exposure and determining transfers of pesticides from surfaces to foods. A protocol, which improved the procedures for collecting appropriate types of samples to evaluate the children's dietary intake model, was developed in FY99. The protocol more accurately characterizes a child's surface-to-hand-to-food process that is potentially a significant source of indirect ingestion exposures. It was evaluated with a field study in FY00 and FY01 and the activities contributing most to the child's excess intake were initially identified as multiple hand-to-food contacts. This protocol was finalized for use in the NERL Longitudinal Field Measurements Study of Infants and Toddlers Aggregate Exposures (CHEERS) conducted under a separate NERL task. The estimated parameters within the model are transfer and activity factors. In order to measure these in the field, a standard food item was developed and tested in a day-care setting in FY02-03. In FY04-05, the protocol will be tested in a residential setting. Model parameters have also been studied by laboratory experiments. In FY98-99, experiments to determine the amount of pesticides that transferred from a contaminated surface to various food items was initiated. In FY00, a new spray chamber was developed which allowed for more uniform spraying and controlled experiments. Transfer of pesticides from contaminated surfaces is dependent on the class of pesticide, surface type, sampling conditions (temperature and humidity), and food type. This research has continued through FY04.

Two manuscripts are being prepared for the field study results and one for the in-house press sampler (transfer) experiments.

Related Publications: Two publications resulted from a completed, related dietary lead study which summarize the preliminary results for the dietary intake model and are included as background information for this work:

Melnyk, L.J., Berry, M.R., Sheldon, L.S., Freeman, N.C.F., Pellizzari, E.D., and Kinman, R.N. "Dietary Exposure of Children Living in Lead-Laden Environments" Journal of Exposure Analysis and Environmental Epidemiology, 2000, 10: 723-731.

Akland, G., Pellizzari, E.D., Hu, Y., Roberds, J.M., Rohrer, C.A.., Leckie, J.O., and Berry, M.R. "Factors Influencing Total Dietary Exposures of Young Children" Journal of Exposure Analysis and Environmental Epidemiology, 2000, 10: 710-722.

Relevance :This research directly supports the USEPA's multimedia approach to human exposure and risk assessment and the goals of FQPA, which requires aggregate and cumulative exposure assessments, including specific children's exposures, for pesticides. Methods development consists of protocols and procedures to measure "true" dietary intake by children, collecting food and other samples and supporting information, and investigating ways to identify, predict and/or reduce exposures via the dietary pathway which supports NERL's multimedia human exposure program and the long-term goal (FQ-1). The model research consists of refining the dietary model for predicting exposure to environmental chemicals for young children (Children's Dietary Intake Model) that accounts for both duplicate diet samples as well as food categories and/or food items that become contaminated while being eaten by the child. Research conducted will improve OPPTS and NERL's understanding of the activities relating to how foods become contaminated by other environmental media. This is an important element in assessing dietary exposure of children which, in turn, will allow clients to regulate and conduct accurate risk assessments (FQ-1). Studies will include laboratory investigations designed to measure the contaminant transfer from various surfaces to different types of foods. This research will also identify and explore the important child dietary scenarios that warrant consideration in exposure assessments. Field studies will be used to validate models, investigate priority scenarios, determine potential excess dietary exposure of young children to selected pesticides, and identify associated activities requiring further research. The results will be used for NERL's multimedia / multipathway human exposure studies by providing protocols to measure dietary exposure in the context of total exposure. These activities are communicated to other NERL personnel through conference calls and planning meetings with NERL's Human Exposure and Atmospheric Sciences Division; to the scientific community by publications and presentations at international meetings; and to OPPTS through program discussions with Assistant Laboratory Directors.

Clients :NERL multimedia field programs, Office of Prevention, Pesticides & Toxic Substances (OPPTS), Office of Pesticide Program, industry

Project IDs:

ID Code :5438

Project type :OMIS