Methanol Poisoning

What’s in today’s article?

• Why in News?
• The Science of Creating Alcohol
• What are adverse effects of Ethanol on Human Health?
• What is Hooch/Spurious Liquor?
• Regulation of Methanol in India
• How can Methanol Poisoning be Treated?

Why in News?

In Tamil Nadu's Kallakurichi, at least 34 people have died and around 100 others are in the hospital after drinking spurious liquor, also known as hooch. It's possible that more people have died than reported, as some may have passed away before reaching medical help.

The Science of Creating Alcohol

• Alcohol is produced using two basic processes: fermentation and distillation. 
• Fermentation is a chemical reaction where yeast or bacteria react with the sugars (from grain, fruits, sugarcane, etc.) to produce ethanol (the alcohol in the drink).
  • Liquor is differentiated by its alcohol content from the 5% by volume (beer) to the 12% (wine) to the 40% (distilled spirits). 
  • Distillation is important because with more of the sugar getting converted to alcohol, the conditions become toxic. 
• Distillation is the process of physically separating the alcohol from the rest of the mixture using evaporation and condensation. 

What are adverse effects of Ethanol on Human Health?

• Ethanol (C2H5OH) is metabolised in the liver and the stomach by alcohol dehydrogenase (ADH) enzymes to acetaldehyde. 
• Then aldehyde dehydrogenase (ALDH) enzymes transform the acetaldehyde into acetate. 
• The adverse effects of alcohol consumption, from the hangover to cancer, are due to acetaldehyde. 
• Contrary to popular belief, the World Health Organization (WHO) has found that “no level of alcohol consumption is safe for health”. 

What is Hooch/Spurious Liquor?

About

• Hooch is a commonly used term for poor quality alcohol, derived from Hoochinoo, a native Alaskan tribe that was known to produce very strong liquor.
• Unlike branded liquor which is produced in factories with sophisticated equipment and rigorous quality control, hooch is made in more crude settings (in many cases homemade) without any quality checks.

Process

• Like all alcohol, hooch is produced using two basic processes: fermentation and distillation.
• Hooch is produced using distillation of a fermented mixture, generally of locally available yeast, and sugar or fruit (often fruit waste).
  • The fermented mixture which is to be distilled contains more than just consumable alcohol (ethanol). 
  • It also contains methanol (CH3OH), a different form of alcohol which is highly toxic for human beings. 
  • During the distillation, both ethanol (boiling point of 78.37 °C) and methanol (boiling point of 64.7 °C) are concentrated. 
  • Thus, if done incorrectly, distillation can lead to an end product which contains high quantities of toxic methanol.
• The end product can have a high concentration of methanol (instead of harmless trace amounts), which is poisonous and can also cause cerebral edema (swelling of the brain), haemorrhage, and death.
• Importantly, it is near impossible to tell whether hooch is safe to consume before actual consumption.
• Dangers associated with hooch
• There is an inherent risk associated with the crude methods of hooch production. 
• The fermented mixture which is distilled contains more than just consumable alcohol (ethanol). 
• It also contains methanol, an industrial alcohol which is highly toxic for human beings.
  • Non-distilled alcoholic beverages like wine contain relatively harmless trace amounts of methanol. 

Regulation of Methanol in India

• Schedule I of the Manufacture, Storage and Import of Hazardous Chemical Rules 1989 includes methanol.
• The Food Safety and Standards (Alcoholic Beverages) Regulations 2018 stipulate the maximum permissible quantity of methanol in different liquors. 
  • For example, these values span a wide range including “absent” in coconut fenny, 50 grams per 100 litres in country liquor, etc.
• The Indian Standard (IS 517) applies to how the quality of methanol is to be ascertained, and together with the Tamil Nadu Denatured Spirit, Methyl Alcohol, and Varnish (French Polish) Rules 1959, what signage, methanol packaging should carry

How can Methanol Poisoning be Treated?

• Once methanol is ingested, the body takes some time to completely eliminate it. There are two immediate ways to treat methanol poisoning. 
• One is to administer ethanol (of a pharmaceutical grade, by healthcare workers). Ethanol competes with methanol for the ADH enzymes. As a result, the methanol is kept from being metabolised to formaldehyde. 

The other option is to administer an antidote called fomepizole, which slows the action of the ADH enzymes, causing the body to produce formaldehyde at a rate that the body can quickly excrete, preventing the deadlier effects from kicking in.

Q.1. What are ADH enzymes?

ADH enzymes, or alcohol dehydrogenase enzymes, are a group of enzymes that facilitate the conversion of alcohol (ethanol) into acetaldehyde in the body. These enzymes are primarily found in the liver and the stomach. 

Q.2. What is ethanol?

Ethanol, also known as ethyl alcohol or grain alcohol, is a clear, colorless liquid that is commonly used as a recreational drug and is the active ingredient in alcoholic beverages. It is produced by the fermentation of sugars by yeasts, and it is also synthesized for use as a solvent, in the production of other chemicals, and as an alternative fuel source.

Source: Tamil Nadu hooch tragedy: Why spurious liquor can be deadly | Indian Express | The Hindu