KOLKATA: The presence of nitrate in drinking water may cause Methaemoglobinaemia, a condition which reduces the blood's ability to carry oxygen.
Most commonly found in bottle fed infants and water from wells in rural areas, this is a major concern.
Controlling nitrate levels in drinking water sources to below 50mg/litre is an effective preventive measure.
Methaemoglobinemia is characterized by reduced ability of the blood to carry oxygen because of reduced levels of normal hemoglobin.
Although uncommon it mostly affects infants. The child may seem healthy except for few symptoms like blueness around the mouth, hands, and feet, hence the common name "blue baby syndrome".
These children may also have trouble breathing as well as vomiting and diarrhoea.
In extreme cases, there is marked lethargy, an increase in the production of saliva, loss of consciousness and seizures. Some cases may be fatal.
In the body nitrates are converted to nitrites. The nitrites react with haemoglobin in the red blood cells to form methaemoglobin, affecting the blood's ability to carry oxygen. Bottle-fed infants less than three months of age are particularly at risk since their haemoglobin is more susceptible, made worse bygastrointestinal infection. Older people may also be at risk because of decreased gastric acid secretion.
The general health of the infant as well as Vitamin C intake may determine whether or not the condition develops
Others at risk for developing methaemoglobinaemia include: adults with a hereditary predisposition, people with peptic ulcers or chronic gastritis, as well as dialysis patients.