Inhalation aerosol exposure

Heat-stable peptide toxin produced by the bacterium Staphylococcus aureus. Developed as a CW agent. Non-volatile, dispersed as an aerosol. Inhalation exposure to < lmg min/m3 produces fever, chills, myalgia, septic shock, death. 

International Standards Organisation, 2007. Workplace Atmospheres—Ultrafine, Nanoparticle and Nano-structured Aerosols—Inhalation Exposure Characterization and Assessment. Document ISO/TR 27628. 

Irregular respiration was observed in both male and female rats after a 4-hour nose-only inhalation exposure to aerosolized endosulfan (Hoechst 1983a). In both male and female rats, dyspnea was observed at the lowest concentrations tested (12.3 and 3.6 mg/m for males and females, respectively). Autopsies of the rats that died revealed dark-red, pinhead-sized foci on the lungs. It is unclear whether these effects represent direct effects of inhaled endosulfan on respiratory tissues or whether they are secondary to central nervous system effects on respiratory function. No treatment-related effects were... 

Available information from human exposures indicates that airborne americium-containing particles are deposited in the respiratory tract, cleared to some extent via mucociliary action, and swallowed or expelled (Edvardsson and Lindgren 1976 Fry 1976 Newton et al. 1983 Sanders 1974 Toohey and Essling 1980). Descriptions of human respiratory tract models that can be used for radiation protection also include relevant information regarding biokinetics of inhaled particles (ICRP 1994b, 1995 NCRP 1997). Quantitative data are not available, however. Supporting animal studies include inhalation exposure to aerosols of americium (Buldakov et al. 1972 DOE 1978 Gillett et al. 1985 Sanders and Mahaffey 1983 Talbot et al. 1989 Thomas et al. 1972) or intratracheal instillation of americium compounds (Moushatova et al. 1996). 

The ICRP (1994b, 1995) developed a Human Respiratory Tract Model for Radiological Protection, which contains respiratory tract deposition and clearance compartmental models for inhalation exposure that may be applied to particulate aerosols of americium compounds. The ICRP (1986, 1989) has a biokinetic model for human oral exposure that applies to americium. The National Council on Radiation Protection and Measurement (NCRP) has also developed a respiratory tract model for inhaled radionuclides (NCRP 1997). At this time, the NCRP recommends the use of the ICRP model for calculating exposures for radiation workers and the general public. Readers interested in this topic are referred to NCRP Report No. 125 Deposition, Retention and Dosimetry of Inhaled Radioactive Substances (NCRP 1997). In the appendix to the report, NCRP provides the animal testing clearance data and equations fitting the data that supported the development of the human mode for americium. 

Intermediate-duration inhalation exposures to aerosols of a few organophosphate ester hydraulic fluids (Durad MP280 and "triaryl phosphate ester") produced lethal neurotoxic effects in chickens and rabbits (MacEwen and Vemot 1983 Siegel 1965). Rats and hamsters appear to be less susceptible to the neurotoxic action of organophosphate esters tests of several organophosphate fluids produced no deaths in rats exposed to substantial aerosol concentrations. 

Polyalphaolefin Hydraulic Fluids. No studies were located regarding ocular effects in humans after inhalation exposure to polyalphaolefin hydraulic fluids. Ocular effects in animals resulting from direct contact with aerosols of polyalphaolefin hydraulic fluids are discussed in Section 2.3, Dermal Effects. 

No data were located regarding absorption in animals after inhalation exposure to organophosphate ester hydraulic fluids or specific organophosphate esters, except for the observation that parent material was not detected by gas chromatography in the blood or urine of male rats exposed to 5,120 mg/m3 of an aerosol of a cyclotriphosphazene (99.9%) hydraulic fluid for 4 hours, thereby suggesting that the extent of absorption was limited (Kinkead and Bashe 1987). Blood samples were collected at 0, 24, and 48 hours after exposure was terminated. Urine was collected for 24 hours after exposure. 

Acute inhalation exposure to aerosols of certain polyalphaolefin hydraulic fluids produced death in rats associated with respiratory tract irritation, while aerosols of other polyalphaolefin hydraulic fluids produced no apparent respiratory tract irritation or deaths (MacEwen and Vemot 1983 Kinkead et al. 1987b, 1992b). The mechanism by which certain polyalphaolefin fluids may produce respiratory tract irritation is not understood. 

No data were located regarding toxic effects in humans following inhalation exposure to polyalphaolefin hydraulic fluids. Three of nine tested polyalphaolefin hydraulic fluids were lethal in rats at 4-hour aerosol concentrations ranging from <5,330 to <10,720 mg/m3. LC50 values for the three lethal fluids in females ranged from 1,390 to 1,670 mg/m3. Deaths were associated with respiratory irritation. The data are inadequate for acute inhalation MRL derivation. No intermediate or chronic inhalation MRLs for polyalphaolefin hydraulic fluids were derived due to the lack of data. 

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. 

Lundgren, D. L., McClellan, R. O. and Hahn, F. F. (1975). Biological effects of repeated inhalation exposure of mice and Syrian hamsters to aerosols of l44Ce02. Ill, page 230 in Inhalation Toxicology Research Institute Annual Report 1974-1975, Report No. LF-52 (Lovelace Foundation, Albuquerque, New Mexico). 

Acute inhalation toxicity To determine the potential acute toxicity-lethality following a single 4-h inhalation exposure to a test atmosphere containing the new pharmaceutical excipient (aerosol, vapor or particles)... 

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