Abstract for Poster 18

 

 

Model experiments for assessing dermal exposure from different spraying operations at workplaces

E. Berger-Preiß¹, I. Mangelsdorf¹, D. Holthenrich², W. Koch¹, S. Melching-Kollmuss*^1
1Fraunhofer Institute of Toxicology and Experimental Medicine, Hannover, Germany
²Federal Institute for Occupational Safety and Health, Dortmund, Germany

Background

Data on dermal exposure during spray application of biocides are sparse in the available literature. Furthermore, it is not quite clear in many of the measurements whether the dermal exposure is related only to the spraying process or to the handling of the biocidal product altogether (i. e. including preparation of the spraying broth). In order to derive general principles for the assessment of exposure during spray applications of liquid biocidal products, a research project was initiated which focused on generating data on inhalational and dermal exposures of spray operators.

Methods

In the first step of the study, simulation experiments with different spraying devices using tracer solutions were carried out in model rooms in order to investigate the influence of different spraying parameters (e. g. spraying equipment, nozzle size, direction of application, type of solvent) on inhalation and dermal exposures. In the second step, the model experiments were verified using exposure data (inhalational and dermal exposures) from field measurements in selected branches where the use of liquid biocidal products by spraying is a relevant factor (e. g. disinfection operations in food and feed areas; pest control operations for private, public and veterinary hygiene; wood protection and antifouling applications). 1 % solutions of fluorescein-Na (aqueous solutions) and 7-diethylamino-4-methylcoumarin (organic solutions) as fluorescence tracers and surrogates for the active ingredient were sprayed. Dermal exposure was assessed using exposure pads. The substance amount per pad was related to the area of the respective part of the body using standard factors in order to determine the amount of active substance deposited on individual body parts. The resulting amounts were added up to calculate the potential total dermal exposure.

Results

In the model experiments dermal exposure depended on the spraying apparatus and on the spraying direction. The spray applicator’s potential dermal exposure decreased in the order: spraying with low pressure (upper part of the room) > fogging > airless spraying > spraying with low pressure (lower part of the room). The dermal dose rates determined varied considerably between the different application techniques. Also the contamination of individual parts of the body was very strongly dependent on the spraying direction and apparatus. As can be seen from the data, the main parameter for potential dermal exposure appears to be the spraying direction, whereas the spraying pressure of the apparatus used was of minor importance.

Using the same spraying devices and techniques, the potential dermal exposure was slightly lower when spraying organic tracer solutions compared to aqueous solutions. The results generated with the model experiments were in good agreement with workplace measurements when using similar spraying devices, conditions and preparations. Furthermore, they show that dermal exposure, compared to inhalational exposure is considerable.

Conclusion

From these results it can be concluded that model experiments could be an alternative way to generate exposure data for health risk assessment and can be used as basis for developing models for dermal exposure assessment.

 

Content last modified: 17 May 2005