Estimation of pesticide exposure to greenhouse applicators using video imaging and other assessment techniques.

Pesticide exposure in greenhouse applicators was measured using the video imaging technique to assess exposure (VITAE) along with dermal patches, air monitoring, and biological assessment techniques. The exposure of five males to pesticides during high- and low-volume application methods in commercial greenhouse operations was evaluated. Failure to use precautionary handling methods when using low-volume applications resulted in the highest level of dermal tracer deposition. Results demonstrated nonuniform deposition of tracer/pesticide mixtures on various body regions, supporting earlier work that questioned the assumption of uniform deposition when assessing exposure with the dermal patch technique. By combining the tracer with an oil-based concentrate, it remained uniformly suspended in the spray solution, and deposition ratios remained constant. Estimates of pirimicarb exposure using the VITAE method were highly correlated with excretion of urinary metabolites (r2 = 0.93). The immediate visual results provided by the VITAE system to applicators proved to be a powerful educational tool in helping them adopt precautionary application techniques. The need to employ protective operating procedures when handling pesticides was demonstrated, no matter how brief the exposure period.

Estimating pirimicarb exposure to greenhouse workers using video imaging.

Exposure of greenhouse chrysanthemum workers to the pesticide pirimicarb was measured by the Video Imaging Technique to Assess Exposure (VITAE) along with air monitoring and biological assessment techniques. Workers at five commercial chrysanthemum operations were video imaged prior to debudding plants which had been treated with a fluorescent tracer and the pesticide, pirimicarb, 36-48 h earlier. After 1-4 h of debudding, workers were again imaged and the rates of tracer deposition determined with the VITAE system. Tracer deposition from contact with treated foliage was found to increase in a linear fashion over 4 h. Greatest deposition occurred on the hands and arms and represented 42% and 20% of total exposure, respectively. No detectable air residue samples of pirimicarb were found while workers were debudding plants. Monitoring of four workers for pirimicarb and its urinary metabolites revealed no detectable residues following 4 h of contact with foliage, which had been treated 48 h earlier.

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.