Student Research: Keith M. Groth
Assessing exposures to chemicals that can be absorbed through the skin presents the industrial hygienist with a perplexing and sometimes frustrating dilemma. The fact that three of the articles appearing in the February 1993 AIHA Journal addressed surface wipe sampling is a testament to an increasing concern over the impact of dermally absorbed chemicals. In addition to increased awareness of percutaneous absorption as a potentially major factor in total body burden, this concern probably is fueled by frequent reductions in the allowable levels of many airborne contaminants for the workplace. As allowable workplace levels drop, the percentage of total body burden that is a result of dermal absorption may increase. This is especially true if dermal exposures are not controlled as rigorously as inhalation exposures. In fact, in many instance where the chemical has a lower vapor pressure and is not aerosolized, dermal absorption is the primary route of exposure.
Several issues must be addressed if VITAE is to be a valid tool for assessing occupation, dermal exposures. First, it must be demonstrated that VITAE predictions correlate well to known tracer densities. Second, it must be shown that the impact of varying skin pigmentation (background grey level) can be controlled across the quantifiable range of the system. Thirs, a lower quantifiable limit must be established and exposures exceeding this limit reliably identified by the system. Finally, it must be shown that an upper quantifiable limit can be determined, allowing investigators to calculate the maximum concentration of tracer that can be introduced and still produce acceptable correlations to contaminant concentration.
Taken from the beginning of thesis.