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INDUSTRIAL HEALTH 1990,28,185-197
Development of an Inhalation System of High Melting
Point Metal Fumes and Its Use for Exposure of
Rats to Chromium and Nickel Fumes
Fumio SERITA, Katsunori HOMMA, Kazuo FUKUDA,
Katsuhiko SAWATARI, Yasutomo SUZUKI and Tadao TOYA
National Institute of Industrial Health
21-1, Nagao 6-chome, Tama-ku, Kawasaki 214, Japan
(Received August 2, 1990 and in revised form October 12, 1990)
Abstract: An experimental inhalation system was developed for fumes generated from powders of high melting point metals such as chromium, nickel, manganese and iron. The system consisted of a plasma flame metal sprayer as a fume generator, a granular bed type fume collector, a fluicized bed areosol generator, an exposure and a control chamber of a horizontal-flow type and inhalant monitoring and controlling units. Performance of the chambers was ensured by a distribution test using flyash as a test aerosol.
Using this system, rats were exposed to chromium fumes for one week or to nickel fumes for two months. The exposure concentrations of the chromium and nickel fumes 1.85[+-]0.55 mg/cube meters and 0.51[+-]0.15mg/cube meters (mean[+-]SD), near the target levels of 2 mg/cube meters and 0.5 mg/cube meters, respectively. The mass median aerodynamic diameter and the geometric standard deviation of the chromium fumes were 2.1mum and 2.00, respectively. Those of the nickel fumes were 3.7mu m and 1.74, respectively. Species analysis of these fume particles revealed that 26.4% of the total chromium was hexavalent and the residue was trivalent and that 1-3% of the total nickel was nickel(III) and the resicue was nickel(II). Inhaled-metal concentrations in the lungs showed steady increases with the exposure periosds and were wihtin the normal range of variation.
On the basis of these results, it is concluded that this system is useful for long-term inhalation experiments using high melting point metal fumes.
Key words: High melting point metals-Fumes-Generation-Chromium-Nickel-Inhalation-Rat
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