You are here:
CHARACTERIZING TRANSFER OF SURFACE RESIDUES TO SKIN USING A VIDEO-FLUORESCENT IMAGING TECHNIQUE
CohenHubal, E A., P P. Egeghy, M. G. Nishioka, AND W. Ivancic. CHARACTERIZING TRANSFER OF SURFACE RESIDUES TO SKIN USING A VIDEO-FLUORESCENT IMAGING TECHNIQUE. Presented at International Society of Exposure Analysis 14th Annual Conference, Philadelphia, PA, October 17-21, 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.
Surface-to-skin transfer of contaminants is a complex process. For children's residential exposure, transfer of chemicals from contaminated surfaces such as floors and furniture is potentially significant. Once on the skin, residues and contaminated particles can be transferred back to the contaminated surface during subsequent contact, lost by dislodgement or washing, or transferred into the body by percutaneous absorption or hand-to-mouth activity. Increased understanding of the relevant factors influencing transfers from contaminated surfaces to skin and the resulting dermal-loading will reduce uncertainty in exposure assessment.
In a previously reported study, a fluorescence imaging system was developed, tested and used to measure transfer of riboflavin residues from surfaces to hands (Ivancic et al. Ann. Occup. Hyg, in press ; Cohen Hubal et al., JEAEE, in press). Parameters evaluated included: surface type, surface loading, contact motion, pressure, duration, and skin condition. Results of this initial study indicated that contact duration and pressure were not significant for the range of values tested, but that there are potentially significant differences in the transfer efficiencies of different compounds.
In this study, the experimental methods were refined and additional transfer data collected. A second tracer, Uvitex OB, having very different physicochemical properties than riboflavin, was also evaluated to better characterize the range of transfers that may be expected for a variety of compounds. The fluorescent tracers were applied individually to surfaces and the transfers to skin were measured after each of seven repeated hand contacts with the surface. Application loadings of 0.2 and 2.0 µg/cm2 were used to approximate loadings that occur in homes after product use.
Results of this study indicate that for the average of all experiments, dermal loadings of both tracers increase in a linear fashion through the seventh contact. Dermal loading of Uvitex tends to increase at a higher rate than dermal loadings of riboflavin. At the 0.2 µg/cm2 surface loading, Uvitex transfers more efficiently than riboflavin.
Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy.