A laboratory evaluation of wipe testing based on lead oxide surface contamination.

Although wipe testing has been used extensively as a measure of surface contamination in industrial hygiene, few scientific studies have been reported to validate the procedure with respect to quantitative recovery, repeatability or methodology. Consequently, a laboratory evaluation of wipe testing with particular attention to the OSHA procedure was undertaken using lead oxide dust as the test contaminant. A dust dispersion system was devised using a Wright dust feeder to produce relatively uniform surface concentrations in an aerosol chamber. Wipe materials included moistened filter paper, commercial paper towels, adhesive paper labels and adhesive tape. The quantitative recovery and repeatability of the wipe procedures were related to surface concentrations and the operational and material variables. Significant improvements in recoveries of up to 90% can be obtained with good repeatability for removable lead oxide dust on non-porous surfaces using moist paper on a fixed test surface area. For porous surfaces, which show significantly lower recovery by all methods, adhesive sampling materials applied at maximum pressure provided an optimum recovery of 77%. The importance of reliable surface contamination measurements in assessing potential health hazards underscores the desirability of improving the demonstrated deficiencies of the OSHA and other wipe sampling procedures.