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CHARACTERIZING PESTICIDE RESIDUE TRANSFER EFFICIENCIES USING FLUORESCENT TRACER IMAGING TECHNIQUES
Citation:
CohenHubal, E A., J C. Suggs, N S. Tulve, AND M. G. Nishioka. CHARACTERIZING PESTICIDE RESIDUE TRANSFER EFFICIENCIES USING FLUORESCENT TRACER IMAGING TECHNIQUES. Presented at American Industrial Hygiene Conference and Exhibition, San Diego, CA, June 1-6, 2002.
Impact/Purpose:
1. To identify those pesticides, pathways, and activities that represent the highest potential exposures to children;
2. To determine the factors that influence pesticide exposures to children;
3. To develop methods for measuring multimedia exposures to children, including methods that account for important activities that take place in home, school, and day care settings;
4. To generate data on multimedia pesticide concentrations, pesticide biomarkers, and exposure factors that can be used as inputs to aggregate exposure models for children.
Description:
To reduce the uncertainty associated with current estimates of children's exposure to pesticides by dermal contact and non-dietary ingestion, residue transfer data are required. Prior to conducting exhaustive studies, a screening study was conducted to identify the important parameters for characterizing these transfers.
In this study, parameters that affect residue transfer from surface-to-skin were evaluated using a fluorescent tracer as a surrogate for pesticide residues. A fluorescent tracer was applied as a residue at levels typical of residential pesticide applications to surfaces of interest. Controlled transfer experiments were conducted by varying contact parameters with each trial. The mass of tracer transferred was measured and the contact surface area estimated using video imaging techniques. In addition, laboratory evaluations were conducted to relate transfer of tracer to transfer of pesticides.
To efficiently identify parameter changes resulting in significant effects, the Youden ruggedness test was used to select the combination of parameters varied in each contact trial. In this way, more than one parameter could be varied at a time and the number of trials required was minimized. Parameters evaluated included: surface type, surface loading, contact motion, pressure, duration, and skin condition. Both transfers onto and off of the hand were measured. For each set of conditions, contacts were conducted sequentially three to seven times. Results of this study show that surface loading and skin condition are among the important parameters for characterizing residue transfers (alpha =.05) and these parameters continue to be significant with repeated contact. Surface type is also significant, though less so under the conditions tested (alpha=.l). Duration of contact is not significant over the range of parameters tested in this study.
This work has been funded by the United States Environmental Protection Agency under contract no. 68-D-99-011 to Battelle. It has been subjected to Agency review and approved for publication.