A new procedure for calibrating the video imaging technique for assessing dermal exposure to pesticides

Improvements in the calibration techniques used in a Video Imaging Technique for Assessing Exposure (VITAE) were examined. A series of standard curves measuring change in fluorescence with increased tracer deposition within narrow pre-exposure skin tone groupings on volunteer human subjects were developed. Nine highly linear curves were generated. Data from these curves were used to develop calibration curves which permitted the computerized correction of fluorescence based on the pre-exposure skin fluorescence. VITAE estimates of dermal tracer deposition were highly correlated with application rates (r2 = 0.98). The fluorescent tracer 4-methyl-7-diethylaminocoumarin was found to be stable for up to 48 h in a greenhouse environment when applied to chrysanthemum foliage or alpha-cellulose patches. The percentage of tracer which could be dislodged from chrysanthemum foliage was constant over 48 h. Improvements in the VITAE calibration techniques increase its value in providing full-body dosimetric estimates of dermal exposure to pesticides in enclosed environments.