Inhaled cerium

Fig. 2b. Bone and liver uptake of inhaled cerium in Class D, W and Y compounds (no radioactive decay) as projected from the TGLD model coupled with the ICRP committee II model for radiocerium,...

Liebscher, K., Schoenfeld, T. and Schaller, A. (1961). Concentration of inhaled cerium-144 in pulmonary lymph nodes of human beings, Nature 192,1308. 

Most of the compounds of cerium are toxic if ingested or if the fumes are inhaled. Cerium will ignite when heated. 

Fig. 9. Rate of solubilization and absorption of l44Ce from lung after inhalation of three forms of cerium.

Fig. 17. Biological model recommended for describing the uptake and retention of cerium by humans after inhalation or ingestion. Numbers in parentheses give the fractions of the material in the originating compartments which are cleared to the indicated sites of deposition. Clearance from the pulmonary region results from competition between mechanical clearances to the lymph nodes and gastrointestinal tract and absorption of soluble material into the systemic circulation. The fractions included in parentheses by the pulmonary compartment indicate the distribution of material subject to the two clearance rates however, these amounts will not be cleared in this manner if the material is previously absorbed into blood. Transfer rate constants or functions, S(t), are given in fractions per unit time. Dashed lines indicate clearance pathways which exist but occur at such slow rates as to be considered insignificant compared to radioactive decay of the cerium isotopes.

Cuddihy, R. G., Gomez, S. R. and Pfleger, R. C. (1975). Inhalation exposures of beagle dogs to cerium aerosols Physical, chemical and mathematical analysis, Health Phys. 29, 257. 

Thomas, R. L., Scott, R. T. and McClellan, R. O. (1971). Influence of carrier cerium on retention and tissue distribution of injected 144Ce in the rat, page 86 in Fission Product Inhalation Program Annual Report 1970-1971, Report No. LF-44 (Lovelace Foundation, Albuquerque, New Mexico). 

Two epidemiology studies have examined mortality among thorium workers neither found significant excess mortality. The standard mortality ratio (SMR) for all causes of death in a cohort of 3039 male workers in a thorium processing plant was 1.05 in comparison to United States white males (Polednak et al. 1983). The estimated radiation levels to the workers for inhalation intake ranged from 0.003-0.192 nCi/m (0.001-0.007 Bq/m ) for a period of 1-33 years. No evidence of overt industrial disease was found in a cohort of 84 workers at a thorium refinery exposed to <0.045-450 nCi/m (<0.002-0.02 Bq/m ) for <1-20 years (Albert et al. 1955). In both studies, the workers were exposed to other toxic compounds (uranium dust) as well as other radioactive materials (thoron, uranium daughters, thorium daughters, cerium). 

Tran, L., Kelly, F., Mudway, I., Morin, J.P., Guest, R., Jenkinson, P., Samaras, Z., Giannouli, M., Kouridis, H. and Martin, P. (2008) Hazard and risk assessment of a nanoparticulate cerium oxide-based diesel fuel additive - a case study. Inhal. Toxicol., 20 (6), 547-566. 

The effect on the central nervous system of the rare-earth metals following inhalation may preclude welding operations with these materials to any large extent. Cerium is stated to produce polycythemia but is useless in the treatment of anemia owing to its toxic effects. The salts of cerium increase the blood coagulation rate. See also RARE... 

The presence of high levels of the radionuclides of cerium, zirconium, ruthenium and transuranic elements in foods and environmental materials indicates the presence of hot particles which may be of special importance in considering exposure by inhalation and/or ingestion. 

Cerium can increase blood coagulation rate and produce gastrointestinal effects. Inhalation can lead to polycythemia. 

An animal inhalation study involved exposure of rats to cerium oxide particles substantially larger than those in diesel emission. The exposure concentrations ranged between 5 and 500mgm for 13 weeks. Effects observed included lung discoloration. 

OTHER COMMENTS alpha-Naphthylamine is an extremely toxic chemical in any of its physical forms, such as flake, dust, liquid, or vapor may be fatal if absorbed through skin, if inhaled, or swallowed personnel should be completely protected against physical contact with this chemical this chemical has been used in the manufacture of dyes and toning prints made with cerium salts the hydrochloride with sulfanilic acid is a reagent for nitrate. 

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