Spacecraft Maximum Allowable Concentrations for Selected Airborne Contaminants Volume 1 (1994) / Chapter Skim
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B5: Freon 113
B5: Freon 113
Pages 121-138
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From page 121... ...
James, Ph.D. Johnson Space Center Toxicology Group Biomedical Operations and Research Branch Houston, Texas PHYSICAL AND CHEMICAL PROPERTIES Freon Il3 is a colorless, odorless, nonflammable liquid at room temperature (Sax, 1984; Tmbus and Atkins, 1972~.
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From page 122... ...
with half-lives for He elimination of FCIl3 in He bream of 0.22, 2.3, and 29 h, respectively. Blood concentrations of FCIl3 approached a plateau after approximately 30 min exposure and peak concentrations were related to the exposure concentrations.
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From page 123... ...
End tidal breath levels taken on the Bird day following the last exposure showed FCll3 concentrations of l.5 ppm in one subject and less than ~ ppm in the over three subjects. A1~ough this result demonstrates that almost all FCT 13 that might have been retained in He tissues under these exposure conditions was eliminated after two successive exposure-free clays, it is not sufficient to establish that a gradual tissue build up of FCIl3 would not occur under continuous exposure conditions.
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From page 124... ...
10,000 ppm (Reinhardt et al., 1973~. At 10,000 ppm, three of four dog exposures resulted in life-threatening cardiac arrhythmias (multiple consecutive ventricular beats or ventricular fibrillations after a challenge close of
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Sleepiness In a limited study involving six rats exposed to 12,000 ppm for up to 24 mo, a slight sleepiness was observed that disappeared immediately after daily exposure stopped (Desoille et al., 1968~.
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From page 126... ...
Dose-response or time-response effects were not demonstrated. Hepatotoxicity Male rats exposed to FCil3 at 1000 or 2000 ppm for 5 cl/w, 6 hid for or 2 w showed subtle changes in liver cells (Vainio et al., 1980~.
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From page 127... ...
biochemical changes reported at 1000 and 2000 ppm actually occurred, and if they did, whether Hey were detrimental or merely adaptive. Chronic Toxicity ~ ~ 13 w Exposure)
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From page 128... ...
heavy exposure to only FCll3 for 2.5-4.5 y: impaired psychomotor speed, impaired learning, and impaired long-term memory (Rasmussen et al., 1988~. Mechanistic Studies Comparison of Me relative potencies of a wide range of halogenatecl anti unsubshtuted hydrocarbons Mat can produce rapidly reversible effects on Me CNS and Me heart suggests Cat these effects are probably structurally nonspecific, i.e.
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From page 129... ...
physical exercise on a treadmill soon after Be EVA, he displayed marked tachycardia incommensurate wig the exercise level and a significant number of isolated supraventricular extrasystoles. Utilization of a number of medical measures, adjustment of the prophylactic program, and stringent organization of the work-rest scheclule led to gradual normalization of cardiac rhythm during exercise.
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From page 130... ...
Synergism FCIl3 has been widely used domestically and industrially as a propellant for pesticide mixtures containing piperony} butoxide (PB) as a synergist to inhibit detoxifying enzymes.
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132 GoGo _' .. a, oo~ I:: ===m ~ofor Cal CQ cn ~ ~ [L1 o D C)
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133 on ~ 2 it, .
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Subtle ulkas~uctural changes in liver cells have been reported at concentrations of 1000 ppm. Heart arrhythmias (usually multiple consecutive ventricular beats or ventricular fibrillations have been induced at concentrations of at least 5000 ppm if the heart has been challenged with exogenous epinephrine.
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From page 135... ...
Cardiac arrhythmias are unacceptable because, although they might not be incapacitating by themselves, some types might signal a substantially increased risk of incapacitating or fatal cardiac injury. The S MAC for a Ih exposure to FCIl3 was set at 50 ppm on the basis of the findings that a 10-m~n exposure to 2500 ppm clid not sensitize dog hearts to the arrhydlmogenic action of epinephrine and then applying a species extrapolation factor of 10 and an additional factor of 5 for possible spaceflight-e~anced sensitivity to arrhythmias.
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From page 136... ...
1983. Cardiovascular examinations and observations of Reconditioning during the space shuttle orbital flight test program.
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1975. Volatile organic components in the Skylab 4 spacecraft atmosphere.
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From page 138... ...
1967. Psychophysiological testing of human subjects exposed to solvent vapors.
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