Defining a tolerable concentration of methanol in alcoholic drinks

Abstract

<jats:p> Methanol, a potent toxicant in humans, occurs naturally at a low level in most alcoholic beverages without causing harm. However, illicit drinks made from “industrial methylated spirits” [5% (v/v) methanol:95% (v/v) ethanol] can cause severe and even fatal illness. Since documentation of a no-adverse-effect level for methanol is nonexistent in the literature a key question, from the public health perspective, is what is the maximum concentration of methanol in an alcoholic drink that an adult human could consume without risking toxicity due to its methanol content? Published information about methanol-intoxicated patients is reviewed and combined with findings in studies in volunteers given small doses of methanol, as well as occupational exposure limits (OELs), to indicate a tolerable (“safe”) daily dose of methanol in an adult as 2 g and a toxic dose as 8 g. The simultaneous ingestion of ethanol has no appreciable effect on the proposed “safe” and “toxic” doses when considering exposure over several hours. Thus, assuming that an adult consumes 425-ml standard measures of a drink containing 40% alcohol by volume over a period of 2 h, the maximum tolerable concentration (MTC) of methanol in such a drink would be 2% (v/v) by volume. However, this value only allows a safety factor of 4 to cover variation in the volume consumed and for the effects of malnutrition (i.e., folate deficiency), ill health and other personal factors (i.e., ethnicity). In contrast, the current EU general limit for naturally occurring methanol of 10 g methanol/l ethanol [which equates to 0.4% (v/v) methanol at 40% alcohol] provides a greater margin of safety. </jats:p>

Chemical Composition of Vintage Preban Absinthe with Special Reference to Thujone, Fenchone, Pinocamphone, Methanol, Copper, and Antimony Concentrations

“…This equates to approximately 1.7% vol of methanol in the absinthe, which nears the maximum tolerable concentration of methanol of 2% vol (39). The cause for the high methanol concentration is most probably the use of denatured industrial alcohol that usually contained around 5% vol of methylene (raw methyl alcohol produced from the dry distillation of wood) (40).…”

Renal Function in Male Sprague-Dawley Rats Concurrently Exposed to Long-Term Nicotine (3-{1-Methyl-2-Pyrrolidinyl}Pyridine) and Methylated Spirits (Methyl Alcohol)

“…Industrial methylated spirits is classically a combination of 5% (v/v) methanol and 95% (v/v) ethanol. [1] A safe daily dose of methanol (methyl alcohol; Mr 32.04 g/mol) in an adult is 2 g, whereas doses of 8 g and excess are toxic. In 2001, the EU general limit for naturally occurring methanol of 10 g methanol per litre of ethanol equates to 0.4% (v/v) methanol at 40% ethanol.…”

“…In 2001, the EU general limit for naturally occurring methanol of 10 g methanol per litre of ethanol equates to 0.4% (v/v) methanol at 40% ethanol. [1] The current workplace exposure limits include: Health and Safety Executive (HSE) Workplace Exposure Limit (WEL): 8-h Time-Weighted Average (TWA), 266 mg.m -3 and 200 ppm; 15-min Short-Term Exposure Limit (STEL): 333 mg.m -3 and 250 ppm. [2] In Australia, methanol poisoning is rare due to legislated removal of methanol from methylated spirits.…”

Nutritional and alcoholic contents of cheka: A traditional fermented beverage in Southwestern Ethiopia

“…The samples coded as K1, S2 and S3 had much higher methanol content than the specifications for maximum methanol and wine (ESA, 2013). All samples had methanol content higher than the maximum limit specified by East African Standards for gin (EAS, 2013) and also half of the samples had more methanol content than the limit set by EU regulation (cited in Paine & Davan, 2001). This shows that there might be the possibility of methanol toxicity in the study localities where the fermentation time is longer.…”

“…However, the presence of toxic substances such as methanol (Fite, Tadesse, Urga, & Seyoum, 1991; Paine & Davan, 2001) in alcoholic beverages puts them in suspicion due to their adverse effects on human health. On the other hand, alcohol (ethanol) in fermented beverages is reported to be the third highest risk for disease and disability, after childhood underweight and unsafe sex (WHO, 2014).…”