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DIETARY EXPOSURES OF YOUNG CHILDREN, PART 1: MODEL DEVELOPMENT AND STUDY DESIGN
Citation:
Melnyk, L J., M R. Berry Jr., G G. Akland, Y. Hu, AND E. D. Pellizzari. DIETARY EXPOSURES OF YOUNG CHILDREN, PART 1: MODEL DEVELOPMENT AND STUDY DESIGN. Presented at ISEA Annual Conference, Monterey, CA, October 24-27, 2000.
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:
Young children contact surfaces (hands, floors, etc.) that may be contaminated with pesticides. Thus, dietary exposures of young children are difficult to measure, but are needed to support the aggregate exposure assessments. Evaluation of dietary field protocols and a total dietary intake model was the goal of this study. Diazinon with a half life of 8 hrs was chosen as the primary pesticide in order to detect a difference in exposure as indicated by the amount of metabolite in urine samples on a daily basis. Other samples collected to determine the model parameters included a 24-hr duplicate-diet, leftover touched and untouched foods, food-surface samples, food-press sampler samples, an activity diary, video tape, hand prints and wipes, surface wipes and press, indoor/outdoor air, entrance soil, and morning urine. One to three year old children were recruited based on diazinon use in their home and a surface wipe screening of diazinon at levels greater than 5 ng/cm2. Sampling was scheduled for six consecutive days following the day of applicabion. The child performed routine activities on exposed days. Controlled activities for eating and handling foods by the child were monitored on alternate unexposed days to determine if differences in exposure were detectable using food, environmental, and morning urine samples. Video tapes were analyzed to obtain contact frequencies and durations. The various samples were successfully collected and dietary exposures calculated from the collected samples. The estimated total dietary exposure calculated from the model will determine if the model adequately predicts dietary exposures of chidlren to pesticides when incorporating their activities.