Spacecraft Maximum Allowable Concentrations for Selected Airborne Contaminants Volume 1 (1994) / Chapter Skim
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B11: Vinyl Chloride
B11: Vinyl Chloride
Pages 185-219
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From page 185... ...
an odor like Hat of ether (ACGIH, 1986~. Synonyms: Formula: CAS number: Molecular weight: Boiling point: Melting point: Vapor pressure: Conversion factors at 25°C, ~ atm: OCCURRENCE AND USE Chloroethene, chloroe~ylene CH2CHC 75-01-4 62.5 -13.9°C Not applicable 2530 mm Hg at 20°C ppm = 2.55 mg/m3 mg/m3 = 0.39 ppm Vinyl chloride is used primarily in the manufacture of polyvinyl chloride resins (ACGIH, 1986~.
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From page 186... ...
Because pretreatment of rats with 6-nitro-l,2,3-benzothiadiazole, which inhibits some m~erosomal cytochrome P-450 pathways, completely blocked vinyl chloride metabolism in rats exposed to vinyl chloride, Bolt et al.
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From page 187... ...
chIoride's epoxide metabolite, 2-chloroethylene oxide, and its rearrangement product, 2-chloroacetalclehycle, could bind to macromolecules in rats. Watanabe and his colleagues showed ~at, in rats exposed to vinyl chloride, the amount of macromolecular binding directly increased with the exposure concentration or phenobarbital pretreatment (Watanabe et al., 1978a,b; Guengerich and Watanabe, 1979~.
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From page 188... ...
In that study, one of six human subjects exposed to viny} chloride at 20,000 ppm for 5 min experienced headache, which lasted for 30 min. Baretta et al.
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From page 189... ...
One of five mice died but no rats or guinea pigs cried at 20,000 ppm. At 30,000 ppm, all five mice and all five rats died, and one of the five guinea pigs died.
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From page 190... ...
Subchronic and Chronic Toxicity Liver Toxicity Liver is We major target organ of viny} chioricie. Liver function impairment and hepatic histological changes have been reported in workers employed in places where vinyl chloride was manufactured or used (Lillis et al., 1975; Popper and Thomas, 1975; Tamburro et al., 1984~.
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From page 191... ...
(1991) 12 of over 100 workers in a polyvinyl chloride plant in Singapore were found to have elevated serum glutamic pyruvic transaminase and gamma glutamy]
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From page 192... ...
found that vinyl chloride produced tubular nephrosis and chronic interstitial nephritis in rats exposed 4 in/d, 5 d/w for ~ y. Tubular nephrosis was also produced in rats exposed to vinyl chloride at 5000 ppm for 7 in/d, 5 d/w for ~ y (Feron and Kroes, 1979~.
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From page 193... ...
shower! Hat 5000 ppm failed to cause any nonneoplastic injuries in the brain of rats exposed 7 in/d, 5 ct/w for ~ y, the NOAEL for brain toxicity is 5000 ppm.
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From page 194... ...
Since emphysema and chronic obstructive pulmonary disease have not been found to be associated why occupational viny! chloride exposures in other epidemiology studies, it is uncertain whether viny]
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From page 195... ...
Both die U.S. and European studies confirmed the findings of earlier epidemiology studies on die excesses of liver cancers in general and angiosarcoma in particular caused by occupational exposures to viny} chloride (Won:,, et al., 1991; Simonato et al., 19914.
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From page 196... ...
It can be concluded from these recent epidemiology studies Mat viny! chIoricle could cause liver cancers in humans, but the evidence Mat vinyl chloride also causes tumors in other sites in humans is rawer weak.
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From page 197... ...
(1983) found that the earlier in life a rat is exposed to vinyl chloride, the higher the tumor risk.
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From page 198... ...
However, Here were no statistically significant increases in tumor incidences in He rats exposed in He last 12 mo of He 2-y study. Based on He data available, He International Agency for Research on Cancer concluded that there is sufficient evidence to support viny} chloride's carcinogenicity to both humans and animals (IARC, 1987~.
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From page 199... ...
In mice, an exposure of 500 ppm for 7 hid on gestation days 6-15 failed to produce any malformations, but vinyl chloride caused increased fetal resorption, decreased fetal weight, reduced litter size, retarded ossification of the cranium and sternum in the fetuses. Viny} chloride exposure at 500 ppm was also toxic to the mothers, causing mortality, reduced bodyweight gain, and decreased liver weight (John et al., 1977~.
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From page 200... ...
These findings support Me theory that vinyl chioride acts Trough its epoxide metabolite formed via m~crosomal oxidation. Therefore, in We event that an astronaut is exposed to vinyl chloride and a known microsomal inducer, one should be aware of the potential toxicity of vinyl chloride.
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202 s of Is _.
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From page 203... ...
203 D <5\ ~t_ ~a, ~=^ ^ - Ax ~ Ax ~^^ 0a at Cat ~ ~ ~Cotcat ·~^ =0 =0To ~ ~To N ~2 An, a, ~I, hi, 5 8 ~ § ~ .
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204 _1 C) PI · C, Cat ~ o Cot · no - m ~ ~ ~ ~ e ~ E e ~ ~ ~ e ~ e ~ Cot ~1 151 ~ bill ~ ~ ~ ~ ·', In .,, ' .
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From page 205... ...
TABLE 114 Spacecraft Maximum Allowable Concentrations Duration ppm 130 mg/m3 Target Toxicity 330 1 h 24 h 7 da 30d 180 d 30 1 1 1 80 2.6 2.6 2.6 Liver dysfunction, CNS impairment, headache Liver dysfunction, CNS impairment Testicular toxicity Testicular toxicity Testicular toxicity aFormer 7~ SMAC = 0.1 ppm. RATIONALE For each toxic end point worth considering, an acceptable concentration (AC)
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From page 206... ...
Two of seven human subjects experienced dryness of the nose and eyes at 500 ppm (Baretta et al., 1969~. Since slight mucosal irritation is acceptable in contingency situations, the 1-h and 24-h ACs are derives!
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From page 207... ...
Due to a lack of data on the time response of viny! chloride's CNS impairment, no acceptable concentrations are estimated beyond 24 h.
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From page 208... ...
(1969) did not detect any changes in Be serum levels of SGPT, alkaline phosphatase, lactic dehydrogenase, and bilirubin in seven workers exposed to vinyl chloride at 500 ppm for 3.5 h or in four workers exposed for 7.5 h (Baretta et al., 1969~.
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From page 209... ...
chloride concentration in the workplace averages 6 ppm and no liver dysfunction would be found at about i.5 ppm. It appears that the NOAEL for non-neoplastic liver toxicity is about I.5 ppm in occupational exposure.
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From page 210... ...
A reduction in testicular weight was noted in rats exposed to viny} chIoricle at 100 or 3000 ppm for 6 in/d, 6 d/w for 6 mot Bi et al. expressed the pathology data by combining We histopatholog~cal data of rats sacrificed after a 3-, 6-, 9-, or 12-mo exposure to viny} chloride at 0, 10, 100, or 3000 ppm.
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From page 211... ...
IS0-d AC based on testicular toxicity = 30-d AC = lppm. Because Here is no evidence that acute vinyl chloride exposures are toxic to He testis, He I-h ant!
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From page 212... ...
Because these toxic end points are not expected to be affected by any microgravity-inducecl physiological changes, Me SMACs are not acijustecl any further. TABLE 11-5 Acceptable Concentrations Acceptable Concentration, ppm Toxic End Point 1 h 24 h 7 d 30 d 180 d Mucosal irritation 500 500 50 50 50 Headache 130 50 - - CNS impairment 130 30 Liver toxicity 130 30 1.5 1.5 1.5 Kidney toxicity - - 20 20 20 Lung toxicity - - 25 25 4 Testicular toxicity - - 1 1 1 Carcinogenicity - 380 55 130 2 SMAC 130 30 1 1 1
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From page 213... ...
1969. Monitoring exposures to viny} chloride vapor breath analysis and continuous air sampling.
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From page 214... ...
1977. Mortality experience of workers exposed to viny} chloride monomer in the manufacture of polyvinyl chloride.
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From page 215... ...
mutagenic risks in communities with polyvinyl chloride production facilities.
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1975. Prevalence of disease among vinyl chloride and polyvinyl chloride workers .
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From page 217... ...
1992. Guidelines for Developing Spacecraft Maximum Allowable Concentrations for Space Station Contaminants.
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From page 218... ...
1978a. Comparison of He fate of vinyl chloride following single and repeated exposure in rats.
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From page 219... ...
1989. Cohort and case-control analyses of workers exposed to vinyl chloride: An update.
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