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Dissolution of cemented carbide powders in artificial sweat: implications for cobalt sensitization and contact dermatitis.

Authors
Stefaniak-AB; Harvey-CJ; Virji-MA; Day-GA
Source
J Environ Monit 2010 Oct; 12(10):1815-1822
NIOSHTIC No.
20037748
Abstract
Skin exposure to cobalt-containing materials can cause systemic immune sensitization and upon repeat contact, elicitation of allergic contact dermatitis (ACD). Data on cobalt dissolution rates are needed to calculate uptake through skin and for development of models to understand risk of sensitization or dermatitis. The purpose of this research was to measure the dissolution kinetics of feedstock and process-sampled powders encountered in the production of hard metal alloys using artificial sweat. The physicochemical properties of each material were characterized prior to evaluation of dissolution behavior. Variations in artificial sweat solvent pH and chemistry were used to understand critical factors in dissolution. Dissolution of cobalt, tungsten, and tungsten carbide was often biphasic with the initial rapid phase being up to three orders of magnitude faster than the latter long-term phase. Artificial sweat pH did not influence dissolution of cobalt or tungsten carbide. Solvent composition had little influence on observed dissolution rates; however, vitamin E suppressed the dissolution of cobalt and tungsten carbide from sintered particles obtained from a chamfer grinder. There was no effect of particle size on dissolution of feedstock cobalt, tungsten, tungsten carbide, and admixture powders. Particle physicochemical properties influenced observed dissolution rates with more cobalt and tungsten carbide dissolving from chamfer grinder particles compared to the feedstock powders or admixture powder. Calculations using the observed dissolution rates revealed that skin exposure concentrations were similar to concentrations known to induce cobalt sensitization and elicit ACD. Observed dissolution rates for cobalt in artificial sweat indicate that dermal uptake may be sufficient to induce cobalt sensitization and allergic dermatitis.
Keywords
Skin-exposure; Skin-irritants; Dermatitis; Exposure-limits; Tungsten-ore; Tungsten-compounds; Tungsten-minerals
Contact
A.B. Stefaniak, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Mailstop H-2800, Morgantown, WV, 26505
CODEN
JEMOFW
CAS No.
7440-48-4; 7440-33-7; 11130-73-7
Publication Date
20101001
Document Type
Journal Article
Email Address
AStefaniak@cdc.gov
Fiscal Year
2011
NTIS Accession No.
NTIS Price
Issue of Publication
10
ISSN
1464-0325
NIOSH Division
DRDS
Source Name
Journal of Environmental Monitoring
State
WV
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