Exposure to mercury through food, water and air can cause significant harm to human health. Methyl mercury, which is the most commonly found form of mercury in the environment, can cause permanent damage to the central nervous system, lungs and kidneys.
Methyl mercury intake through fish can put unborn foetuses at great risk. The mercury can cross the placental barrier and cause foetal brain damage without any symptoms in the expectant mother. Newly born infants may experience mental and physical disabilities and delayed development of motor and verbal skills.
The symptoms of methyl mercury poisoning are varied and difficult to detect as they can mimic other illnesses. In relatively mild cases, the condition is barely distinguishable from common ailments. Some common symptoms are headache, fatigue, numbness of extremities, depression, memory loss, and in extreme cases, madness, coma or death.
Then why, despite such high levels of mercury in the environment and food chain, has India not yet witnessed a Minamata-like disaster? (see box)
To start with, no comprehensive study linking mercury pollution and health has been made in India. Mercurys health impacts are chronic and take time to manifest. Short-term impacts are so similar to normal diseases that they are difficult to isolate. Long-term impacts, such as neurological disorders, cardio-vascular problems and possibly cancer, can also be caused by other factors. Although the cancer rate in India is growing alarmingly, nobody can say for sure that it is caused by mercury pollution.
Minimata was a small area, where a large proportion of people had similar diet patterns. In India, mercury poisoning affects a widespread population. Studies also indicate that a healthy diet could neutralise some adverse impacts of mercury. Therefore it is the poor who are the most affected. l