New Delhi, Nov. 3: Eat fish, be healthy — that’s what doctors have been saying till now. Maybe, not anymore.

Environmentalists are now pointing to serious health problems that can arise from eating too much of the denizens of the deep as they contain high levels of mercury.

“The coastal areas of India are significantly polluted with high levels of mercury in Indian fish, both saline and freshwater,” says the Centre for Science and Environment.

Dr R.C. Srivastava, co-chairperson of the global mercury assessment drafting group and a former deputy director of Indian Toxicological Research Centre, believes it could be harmful for pregnant women to have such contaminated fish for more than twice a week.

“We have no proper data on what is happening to the mercury levels and what could be the safety limits. People, especially those living in the coastal areas, should know about the dangers they are exposed to,” he stresses.

According to the CSE, the compound methyl mercury is a confirmed neurotoxicant and damages the developing brain. It passes through the placental barrier and the blood-brain barrier, putting the unborn at tremendous risk.

“There is no method of reducing mercury content in fish through cleaning or cooking since mercury is tightly bound to proteins in all fish tissue,” say experts.

At a CSE-sponsored discussion on the dangers posed by mercury pollution, environmental and medical experts today expressed concern about India continuing to use mercury compounds in its industrial chemical processes. In developed countries, the use of mercury is either banned or regulated.

Thermometers, batteries, fluorescent lamps, thermostat switches, dental fittings, alarm clocks, hearing aids and cosmetics, including hair dyes and creams, contain mercury.

Mercury can be released into the air when coal, oil or wood is burned as fuel or when mercury-containing wastes are incinerated. Lakes and rivers are contaminated when there is a direct discharge of mercury-laden industrial or municipal waste into the water.

“The potential release of mercury into India’s environment could be anything between 172.5-200 tonnes every year,” the CSE says. In 2000, the ministry of environment and forests issued a notification for a phased elimination of mercury from consumer products, but no action has been taken so far.

According to Jagjit S. Chopra, the president of Neurological Society of India, the two organs most affected by mercury are the kidney and the brain. “It has severe neurological effects like depression, suicidal tendencies, loss of memory, Alzheimer’s Disease, numbness of the nerves and paralysis,” says Chopra.

Other symptoms include loss of appetite, repeated occurrence of infections and bleeding gums. “There are serious reproductive health hazards like frequent abortions, mentally challenged babies and impotency,” says Chopra. That is not all. Occupational absorption of mercury could also lead to fever, chills, respiratory diseases, abdominal cramps, vomiting, lethargy, confusion and abnormal heart rhythm.

Along with the US, India is among the biggest consumers of mercury.

It now consumes 50 per cent of the global production of mercury. Mercury imports into India have doubled between 1996 and 2002 from 254 tonnes a year to 531 tonnes.