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Samples of fish species tested from Chennai have shown positive for formalin. It is a cancer-inducing chemical used illegally to preserve fish.

Why it is used:

  • In Fish industry ,formalin or formaldehyde is sprayed on the fish or injected into the fish or the fish is dipped into the solution. This helps keep the fish fresh for a longer time.
  • When formalin is used the gills remain red for longer periods.


  • A solution of 35 to 40 per cent of water in formaldehyde.
  • Formalin is a colourless strong-smelling, toxic, flammable, explosive liquid substance usually used in industry of textiles, plastics, papers, paint, construction, and well known to preserve human corpse.
  • It is also used as raw material for organic combination, formaldehyde resin, plastic production, organic material synthesis, disinfection, and anatomic preparation conservation, as fungicide.
  • Effective against viruses.
  • Effective against mycobacteria so used as an antiseptic in sterilising surgical instruments.
  • It’s vapour together with air form explosive compounds.
  • Exposure from its gas or vapor can cause irritation to the eyes, nose and respiratory tract, causing sneezing, sore throat, larynx constriction, bronchitis and pneumonia. Multiple exposures can lead to asthma. It can also affect the skin, causing dermatitis or allergic reaction.
  • Formalin that was recently found in food, might not give such obvious reactions. However, this substance is known to be a carcinogenic substance, can precipitate cancer. Some other studies also show formalin will cause kidney, liver, and lung problems.
  • Formalin will make the fish become stiff, whitish and odourless. Even when cooked, i.e. fried, it will still be stiff.
  • Formalin must be disposed though the hazardous chemical waste disposal program.
Schizostachyum and amanicum – The bamboo species endemic to Andaman nicobar island. A green alternative to use-and-throw plastic drinking straws. Usually the bamboo species cannot be used as a straw. But this species can be. Bamboo straw biodegradable, it can be reused for years.

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