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4 Methanol
Pages 126-146

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From page 126... ... Its physical and chemical properties are shown in Table 4-1. TABLE 4-1 Physical and Chemical Properties of Methanol Formula CH3OH Chemical name Methanol Synonyms Methyl alcohol, wood spirit, carbinol, Columbian spirits, wood alcohol, wood naphtha, methyl hydroxide, hydroxy methane, methyl hydrate, methylol, monohydroxymethane CAS registry no. Read the entire page →
From page 127... ... It is used industrially in the manufacture of other chemicals and as a solvent. It is added to various commercial and consumer products, including windshield washing solutions, deicing solutions, glass cleaners, duplicating fluids, solid canned fuels, paint thinners and removers, model airplane fuels, embalming fluids, lacquers, inks, and some formulations of gasohol motor fuel. Read the entire page →
From page 128... ... 128 Spacecraft Water Exposure Guidelines TABLE 4-3 Background Blood Methanol and Formate Concentrations in Humans Methanol, mg/dL Formate, mg/dL Mean ± SD Mean ± SD Subjects (Range) (Range) Read the entire page →
From page 129... ... . Short-term inhalation exposure of adult volunteers to methanol vapors at 800 ppm for 0, 0.5, 1, 2, and 8 h produced maximal average blood methanol concentrations of 0.06, 0.53, 0.66, 1.40, and 3.07 mg/dL, respectively (Batterman et al. Read the entire page →
From page 130... ... . Two mechanisms may be operative in explaining low formate oxidation in species susceptible to methanol toxicity: low hepatic tetrahydrofolate concentrations and reduced hepatic 10-formyltetrahydrofolate dehydrogenase activity (Johlin et al. Read the entire page →
From page 131... ... 1991 reasoning effects 200 ppm vapors Inhalation 4h Humans, n = 26 NOAEL for visual, neurophysiologic, and Chuwers et al 1995 neurobehavioral effects 200 ppm vapors Inhalation 4h Humans, n = 26 No significant increase in formate in serum or D'Alessandro et al. urine 1994 200 ppm vapors Inhalation 4h Humans, n = 22 Serum methanol increased 4-fold to 6.5 mg/L; Osterloh et al. Read the entire page →
From page 132... ... formate in blood Subchronic Exposures (11-100 d) 2,500 mg of Ingestion 90 d Rats, male and LOAEL for elevated SGPT and SAP and EPA 1986 methanol/kg/d female, Sprague- decreased brain weight Dawley, n = 30/sex/dose 365-3,080 ppm vapors Inhalation 1 h/wk – 40 Teacher aids, Dose-dependent incidence of blurred vision, Frederick et al. Read the entire page →
From page 133... ... No detectable effects were seen except for two tests in which minor effects were within the range of test values seen in control subjects exposed to air. No significant neurobehavioral effects were seen in 26 volunteers exposed once for 4 h to 200 ppm of methanol vapors and tested for color discrimination (Stroop test and Lanthony 15) Read the entire page →
From page 134... ... . Clinical observations in methanol-intoxicated humans have shown that, in its initial stages, developing ocular toxicity can be reversed, even >24 h after methanol ingestion, by treatments such as bicarbonate, fomepizole or ethanol, intravenous folinic acid, and dialysis, which reduce blood formate concentrations and metabolic acidosis (Barceloux et al. Read the entire page →
From page 135... ... epidemiology study of adverse health effects in 66 female teacher aides exposed to methanol vapors from duplicating fluid (99% methanol) found that aides exposed to 365-3,080 ppm of methanol reported significantly more blurred vision, headache, dizziness, and nausea than a comparison group of 66 unexposed female teachers randomly selected from 287 respondents to the questionnaire (Frederick et al. Read the entire page →
From page 136... ... In CD-1 mice, inhaled methanol vapors caused developmental abnormalities (neural and ocular defects, cleft palate, hydronephrosis, Read the entire page →
From page 137... ... However, rodents are poor models for methanol toxicity in humans. In addition, for a given daily dose rate, the use of gavage treatments would be expected to result TABLE 4-5 Drinking Water Standards for Methanol Set by Other Organizations Organization, Reference Standard Amount Concentration EPA 1993 Reference dose 0.5 mg/kg/d 12.5 mg/La (oral, chronic) Read the entire page →
From page 138... ... ; STEL, short-term exposure limit; TLV, Threshold Limit Value; TWA; time-weighted average. in higher peak blood methanol concentrations compared with what would be expected from smaller fractionated doses throughout the day for drinking water exposures. Read the entire page →
From page 139... ... Spaceflight Effects None of the reported adverse effects of methanol exposures are known to be affected by spaceflight, but the 1.7% to 12% reduction in total body water associated with prolonged microgravity would proportionately increase the blood concentration of any methanol ingested. This effect is too small to significantly change the spacecraft water exposure guideline (SWEG) Read the entire page →
From page 140... ... Thus, in calculating an acceptable concentration of methanol in drinking water, the use of the longest half-life (3.6 h) seen in any tested individual at low doses should provide a high level of confidence that methanol concentrations that do not exceed the calculated concentrations will not produce methanol toxicity in astronauts. Read the entire page →
From page 141... ... TABLE 4-8 Acceptable Concentrations for Methanol Uncertainty Factor Acceptable Concentrations, mg/L Exposure Inter- LOAEL to Inter- SpaceEnd Point Data Species individual NOAEL species Time flight 1d 10 d 100 d 1,000 d NOAEL for neuro- 200 ppm, Human, 0.51 1 1 PK model 1 40 40 40 40 behavioral toxicity 4h n = 26 SWEG 40 40 40 40 141 Read the entire page →
From page 142... ... in the blood, SWEG values for exposures >1 d should be set to ensure that methanol does not accumulate in the blood -- that is, the peak methanol concentration does not increase during a multiday exposure. Thus, the methodology used to calculate blood methanol kinetics for a 1-d SWEG of 40 mg/L can also be applied to calculating SWEG values for 10, 100, and 1,000 d. Read the entire page →
From page 143... ... , 670 mL at 12 h, 400 mL at 15 h, 670 mL at 19 h, and 400 mL at 21 h, repeating each 24-h period. REFERENCES ACGIH (American Conference of Governmental Industrial Hygienists) Read the entire page →
From page 144... ... 1995. Neurobehavioral effects of low-level methanol vapor exposure in healthy human volunteers. Read the entire page →
From page 145... ... 1992. Lack of blood formate accumulation in humans following exposure to methanol vapor at the cur rent permissible exposure limit of 200 ppm. Read the entire page →
From page 146... ... 1981. Blood methanol concentrations in normal adult subjects administered abuse doses of aspartame. Read the entire page →

From page 126...

... Its physical and chemical properties are shown in Table 4-1. TABLE 4-1 Physical and Chemical Properties of Methanol Formula CH3OH Chemical name Methanol Synonyms Methyl alcohol, wood spirit, carbinol, Columbian spirits, wood alcohol, wood naphtha, methyl hydroxide, hydroxy methane, methyl hydrate, methylol, monohydroxymethane CAS registry no.

4 Methanol Pages 126-146

4 Methanol
Pages 126-146