Formalin is a 37-50% aqueous solution of formaldehyde used as an antiseptic, disinfectant and as a preservative. To prevent polymerisation of formaldehyde solution about 10-15% of methyl alcohol is added to form Formalin. Formalin is a highly toxic systemic poison that is well absorbed by inhalation.
It has extensive uses such as in adhesive and plastic, pressed wood products as nail hardener and polish, cosmetic, disinfectants and recently as illegal preservative of food stuffs. In air it is readily broken down by sunlight, with a half-life of approximately 30-50 minutes but in liquid form, it is stable over time. Formaldehyde is quickly absorbed from the gastrointestinal tract following ingestion and from the respiratory tract following inhalation which makes it a dangerous chemical to be used as preservative. However, it is inadequately absorbed following dermal contact. The vapor is a severe respiratory tract and skin irritant and on contact can cause severe burns to the eyes and skin. Formalin is a toxic substance that can kill bacteria and virus but at the same time damage human cells. It can prolong the shelf life of food stuffs by protecting against deterioration cause by microorganism. There are reports that currently formalin is been used widely and illegally in fishes to keep it fresh. The wide spread use of formalin in the preservation of fishes, meat, fruits, vegetables and milk for long term preservation pose a massive threat to public health at an alarming level. Several studies on experimental animals demonstrated a wide number of toxic effects including stomach lesions, allergy, asthma, abdominal pain and vomiting. Experiments on animals on ingestion of formalin showed pharyngeal and gastric irritation with a significant increase in the thickness of stomach lining epithelium and irritation to the mucus membrane. Formalin is significantly related with cancer particularly nasopharyngeal cancer in humans through inhalation during occupational exposure and can cause gastrointestinal cancer when administered with drinking water in high concentration. Ingestion of large amount of formalin can cause severe abdominal pain, vomiting, cancer, renal injury and possible death in humans.
Due to abundant use of formalin in different food items and consumption of the foods adulterated with this dangerous chemical, a huge number of population particularly the kids and the elderly are exposing themselves everyday to severe health hazard.
Experiments on mice after thirty-days of oral administration of formalin showed significant effects on the kidneys and liver. The animals fed with formalin mixed food showed that glomeruli (which is responsible for the normal functioning of the kidney) were degenerated, shrunken, ruptured and deformed. Similar damage to the cells of the liver were also observed. It is suspected that similar effects in the human kidneys and liver apart from other tissues/organs will occur following long term ingestion of formalin laced food stuffs. This probably explains the increasing number of chronic kidney diseases requiring dialysis and chronic liver diseases in the Naga population of late.
Naga Hospital Authority Kohima