methanol

A fatal case involving a 41-yr-old man who had ingested a large quantity of methanol disclosed a broad distribution of methanol in postmortem tissues and fluids. The highest content of methanol was found in the kidney (5.13 g/kg) followed by the liver (4.18 g/kg), vitreous humor (3.9 g/L), heart (3.45 g/kg), urine (3.43 g/L), pericardial fluid (3.29 g/L), blood (2.84 g/L) and stomach contents (2.21 g/L).

Pesticide Ecotoxicity Data from EPA: 1

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), methanol, which has a vapor pressure of 127 mm Hg at 25 °C(2), is expected to exist solely as a vapor in the ambient atmosphere. Vapor-phase methanol is degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals(SRC); the half-life for this reaction in air is estimated to be 17 days(SRC), calculated from its rate constant of 9.0X10-13 cu cm/molecule-sec at 25 °C(3). The major degradation product from reaction with hydroxyl radicals is formaldehyde(4).

The measured Koc for methanol is reported to be 2.75(1). According to a classification scheme(2), this estimated Koc value suggests that methanol is expected to have very high mobility in soil(SRC).

ANAEROBIC: Approximately 83-91% biodegradation was observed in an anaerobic die-away test, using marine water and sediment from the San Francisco Bay during a 3-day incubation period(1). Methanol was found to be susceptible to biodegradation in low oxygen subsurface regions in microcosm studies simulating subsurface conditions; complete degradation was observed within one year or less(2). Methanol degraded readily in test tube microcosms simulating subsurface soils and groundwaters from sites in VA and NY(3). Soil-sediment suspensions, maintained under anaerobic conditions, resulted in a 5-day CO2 evolution (14-C) of 46.3%(4).

Measured BCF values of less than 10 were reported for fish (golden ide (Leuciscus idus melanotus)) exposed to 0.05 mg/L of methanol for three days in an aquatic tank(1). According to a classification scheme(2), this BCF suggests the potential for bioconcentration in aquatic organisms is low(SRC).

The measured Henry's Law constant for methanol at 25 °C is 4.55X10-6 atm-cu m/mole(1). This Henry's Law constant indicates that methanol is expected to volatilize from water surfaces(2). Based on this Henry's Law constant, the volatilization half-life from a model river (1 m deep, flowing 1 m/sec, wind velocity of 3 m/sec)(2) is estimated as 4.6 days(SRC). The volatilization half-life from a model lake (1 m deep, flowing 0.05 m/sec, wind velocity of 0.5 m/sec)(2) is estimated as 35 days(SRC). Methanol's Henry's Law constant indicates that volatilization from moist soil surfaces may occur(SRC). The potential for volatilization of methanol from dry soil surfaces may exist(SRC) based upon a vapor pressure of 127 mm Hg(3).

The rate constant for the vapor-phase reaction of methanol with photochemically-produced hydroxyl radicals is 9.0X10-13 cu cm/molecule-sec at 25 °C(1). This corresponds to an atmospheric half-life of about 17 days at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(1). Methanol is not expected to undergo hydrolysis in the environment due to the lack of functional groups that hydrolyze under environmental conditions(2). Methanol does not contain chromophores that absorb at wavelengths >290 nm(2), and therefore is not expected to be susceptible to direct photolysis by sunlight(SRC). Methanol in aqueous solution exhibited no degradation when exposed to sunlight using an EPA test protocol(3). Sediment and clay suspension solution did not photocatalyze the degradation of me...

RAIN WATER: Methanol was detected at a mean level of 22 ppb in thunderstorm water collected from Santa Rita, AZ in Sept, 1982(1).

Some distilled fruit spirits contain, normally, high quantities of methanol. ...

ENVIRONMENTAL: Methanol was detected in 1 of 12 samples of human milk collected from volunteers in 4 USA cities(1).

Methanol levels of 18-70 ppm were detected in wastewater effluents from an unspecified US specialty chemical manufacturing facility (near a large brackish river which emptues into an estuary), but none was detected in associated river water or sediments(1). Methanol has been identified in wastewater effluents from chemical, paper, and latex manufacturing plants and from sewage treatment plants(2). Concentration of 42.4 ppm detected in leachate from the Love Canal in Niagara Falls, NY(3). Concentration of 1050 ppm detected in condensate waters from a coal-gasification plant(4). Levels of 0.1-0.6 ppm were found in exhausts from engines using simple hydrocarbon fuels(5). Methanol has been identified in exhausts from both gasoline and diesel engines(6).

Avoid release to the environment in circumstances different to normal use.

A small amount of methanol is found in the expired breath of normal subjects, possibly by endogenous metabolic production.

SOURCE DOMINATED: Methanol was tested for but not detected in gaseous emissions from a mechanical biological treatment plant for municipal solid waste, treating 1200 t/day(1).

Methanol's production and use as a solvent, fuel additive, and in the production of formaldehyde, acetic acid, and dimethyl terephthalate, chemical synthesis, antifreeze, fuel for utility plants, fermentation feedstock and home heating oil extender(1) may result in its release to the environment through various waste streams(SRC). Methanol's use in hydraulic fracturing fluids(2,3) will result in its direct release to the environment(SRC). The largest anthropogenic source of methanol release to the environment is evaporation from solvent uses which amounts to an estimated 1.1 billion lbs annually(4). Annual emission releases from methanol production, end-product manufacturing, and storage/handling have been estimated to be 68, 49, and 12 million lbs, respectively(4). Methanol has been id...

Although individual responses of man to methyl alcohol may vary considerably, industrial exposures are not very hazardous if concentrations are maintained within upper limit of 200 ppm by proper ventilation.

Methanol was identified as a component of several industrial paint strippers(1). Engine exhausts from both gasoline and diesel vehicles have been found to contain methanol(2). Methanol has been identified as a constituent of tobacco smoke(3,4), tobacco and tobacco substitute smoke(4).

Methanol's production and use as a solvent, fuel additive, and in the production of formaldehyde, acetic acid, and methyl tertiary butyl ether (MTBE) may result in its release to the environment through various waste streams. Its use in hydraulic fracturing fluids will result in its direct release to the environment. It can also be released directly to the environment in exhaust gases from combustion engines. Methanol has been identified as a natural emission product from various plants and as a biological decomposition product of biological wastes and sewage; natural emission sources include volcanic gases, vegetation, microbes, and insects, and methanol is a product of decaying organic material. If released to the atmosphere, a vapor pressure of 127 mm Hg at 25 °C indicates that metha...

Methanol can produce sensory irritation and narcosis at airborne concentrations below those which produce organ system pathology. (T10)

Eyes, skin, respiratory system, central nervous system, gastrointestinal tract

LC50 (rat) = 64,000 ppm/4 hr

Acute methanol poisoning in humans is characterized by an asymptomatic period of 12h to 24h followed by formic acidemia, ocular toxicity, coma, and in extreme cases death. Visual disturbances develop between 18h to 48h after ingestion and range from mild photophobia and blurred vision to markedly reduced visual acuity and complete blindness. (T10)

Reproductive Toxin - A chemical that is toxic to the reproductive system, including defects in the progeny and injury to male or female reproductive function. Reproductive toxicity includes developmental effects. See Guidelines for Reproductive Toxicity Risk Assessment.

Oral (T10)

The target of methanol in the eye is the retina, specifically the optic disk and optic nerve. Muller cells and rod and cone cells are altered functionally and structurally, because cytochrome oxidase activity in mitochondria is inhibited, resulting in a reduction in ATP. (T10)

Oral Subchronic Chronic Reference Dose Reference: HEAST Current

No indication of carcinogenicity to humans (not listed by IARC).

It has been suggested that the metabolic acidosis due to methanol might be exacerbated in individuals with diabetes since it is well known that these patients suffer from diabetic ketoacidosis. However, there are no clinical or experimental data on any interaction between methanol acidosis and diabetic ketoacidosis.

Soil Saturation Concentration (mg/kg): 1.06e+05

Soil Saturation Concentration (mg/kg): 1.06e+05