Semester

Summer

Date of Graduation

2010

Document Type

Thesis

Degree Type

MS

College

Statler College of Engineering and Mineral Resources

Department

Industrial and Managements Systems Engineering

Committee Chair

Steve Guffey

Abstract

Metal and metal alloys are critical components of high-tech applications. Beryllium (Be), chromium (Cr), and nickel (Ni) are among the most economically important metals for high-tech applications because of their extraordinary physical properties. These metals pose two different problems for workers who work with them: (1) allergic contact dermatitis from exposure to Cr and Ni, which is widely accepted to account for a significant percentage of occupational skin irritations and (2) possible systemic sensitization from skin contact with airborne Be. Proper assessment of skin contact with allergenic metals during work is difficult. Current practices for the assessment of skin exposure are to either remove a sample of material from the skin surface or to intercept a sample of the material using a substrate such as cotton gloves or cloth patches. Upon collection, the metal content of the sample is dissolved completely using strong acids, followed by analysis using atomic spectroscopy. While this analytical approach is chemically valid (i.e., nitric acid and hydrochloric acid to dissolve beryllium, (NMAM 7303), a major shortcoming of this approach is that the masses of metals are reported without consideration of the bioaccessible (i.e., available for absorption) form and mass. The bioaccessible (water-soluble) form of these metals is of utmost concern because it is the form that can be readily absorbed through the upper layer of the skin and into the immunologically-active layer of the epidermis. This study investigated the extraction of bioaccessible forms of Be, Cr, and NI under physiologically relevant conditions as an alternative to acid-assisted digestion procedures in current use. Simulated human sweat was used to extract and quantify Be, Cr, and Ni metals in their bioaccessible forms. Specifically, this study evaluated the influence of simulated sweat contact time and skin temperature on the dissolution of Be, Cr, and Ni powders. Results from this study will be used to define the optimal simulated human sweat conditions for the dissolution of metal sensitizers into their bioaccessible forms for exposure assessment.

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