Factors influencing total dietary exposures of young children

Abstract

A deterministic model was developed to identify the critical input parameters needed to assess dietary intakes of young children. The model was used as a framework for understanding the important factors in data collection and data analysis. Factors incorporated into the model included transfer efficiencies of pesticide from surfaces to food, transfer efficiencies of pesticide from surfaces to hands to food, and more accurate microactivity data related to contact frequency for the three variables of interest Ð hands, surfaces, and food. Results from range -finding measurements of transfer efficiencies using an aqueous pesticide solution of a mixture of malathion, diazinon, and chlorpyrifos sprayed on the surfaces indicate that a higher pesticide transfer occurred from hard surfaces to food ( hardwood, plastic ) , with low transfer from soft surfaces ( carpet, cloth ) . Six children, all less than 4 years old, were videotaped to obtain realistic contact frequency and times for the interaction of hands, surfaces, and foods during eating meals and snacks while in their homes or day care centers. The time range of eating events varied from about 2 to 55 min, with an average of about 20 min. The average number of contact frequencies between food and hands was 19 times for each eating event, with a range of 10 ± 40. Contacts between the surface and hand were about the same as the food and hands. Contacts between foods and surfaces ranged from 0 to 32, but only five or less of the contacts per eating event were associated with surfaces other than eating utensil. The children's microactivity data collected during the eating events, together with the laboratory results from the transfer studies, were provided as input into a Monte Carlo simulation of the dietary ingestion model. Simulation results indicate that children's handling of the food could contribute 20 ± 80% of the total dietary intake of pesticides. Dietary exposure due to residues in the food before handling accounted for 16% and 47%, respectively, of the total mean intake from simulations for a child's consumption of an apple or banana. These results indicated that transfer efficiencies for foods on various surfaces typically found in homes as well as children's hand contacts with the food and surfaces are important as determinants of dietary exposure. Journal of Exposure Analysis and Environmental Epidemiology ( 2000 ) 10, 710 ± 722.

Influences on transfer of selected synthetic pyrethroids from treated Formica to foods

“…This was evident from historical data (Akland et al, 2000;Rohrer et al, 2003). Therefore, the loadings on the foods must be normalized by calculating TEs.…”

“…And, because it is very difficult or impossible to capture handled food samples as they enter the mouths of young children, it is necessary to find procedures to fully characterize and evaluate this potentially important pathway. The Children's Dietary Intake Model (CDIM) has been developed to predict total dietary intake incorporating excess exposures because of handling of food before consumption (Akland et al, 2000;Hu et al, 2004). The model includes three terms added together to estimate intake of a single contaminant: Term 1 is the pesticide residue in the food; Term 2 is the contribution from surface-to-food contacts;…”

“…Earlier studies, conducted in the laboratory, determined TEs between certain food and surface combinations (Rohrer et al, 2003;Vonderheide et al, 2009a). The impact of activities, such as surface contacts of a single food item or contacts with food items in multiple locations, on the transfer of contaminants is largely unknown or has been estimated (Akland et al, 2000;Hu et al, 2004).…”

Surface-to-food pesticide transfer as a function of moisture and fat content

“…Such exposures, termed excess dietary exposures, are derived from contact between foods and contaminated surfaces (Melnyk et al, 2000). Limited data exist concerning these transfers, but they are thought to be a critical element in predicting total dietary exposure (Akland et al, 2000;Melnyk et al, 2000;Hu et al, 2004).…”

“…Children are particularly susceptible to such added exposures due to unstructured eating behaviors (Goldman, 1995;Landrigan et al, 1999;Hubal et al, 2000) and as a result, these activities can become an important factor in determining total dietary intakes (Akland et al, 2000;Melnyk et al, 2000;Freeman et al, 2001). In an effort to account for all routes of intake, a Children's Dietary Intake Model (CDIM) was developed (Akland et al, 2000).…”