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DEVELOPMENT OF EVALUATION OF A QUANTITATIVE VIDEO-FLUORESCENCE IMAGING SYSTEM AND FLUORESCENT TRACER FOR MEASURING TRANSFER OF PESTICIDE RESIDUES FROM SURFACES TO HANDS WITH REPEATED CONTACTS
Ivancic, W., M. G. Nishioka, R. Barnes, E A. CohenHubal, M. Morara, AND S. Bortnick. DEVELOPMENT OF 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 48(6):519-531, (2004).
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.
A video imaging system and the associated quantification methods have been developed for measurement of the transfers of a fluorescent tracer from surfaces to hands. The highly fluorescent compound riboflavin (Vitamin B2), which is also water soluble and non-toxic, was chosen as the tracer compound to simulate the transfers from surfaces to hands of pesticide residues deposited on carpeted and laminate surfaces of a residence. The system was designed around the unique properties of riboflavin. Excitation energy was centered near 440 nm (in the blue region of the visible spectrum); emitted energy was measured at 600 nm (in the red/orange region), well beyond the significant fluorescence peak maximum of natural skin. A video camera system with an image intensifier was interfaced to an image processing analysis software system. Quantification utilized chemometric techniques to account for the non-linearity of pixel detectivity and non-linear excitation strength. Method quantification and detection limits were approximately 0.1 ug/cm2 and 0.02 ug/cm2, respectively. The relative error was ~100% at the quantification limit, but <20% at higher levels. Transfers of riboflavin to hands, resulting in dermal loadings in the range of 0.1 - 2.0 ug/cm2, were measured with this system from surfaces whose loadings approximated the pesticide levels that occur in homes after broadcast application.
This work has been funded by the US EPA under contract No. 68-D-99-011 to Battelle. It has been subjected to agency review and approved for publication