High levels of mercury seen in Hyderabad residents

Hyderabad: The mercury level in the bodies of people living in Hyderabad, Nellore and Goa has been found to be higher than the prescribed safe level owing to their proximity to active coal-fired power plants and consumption of contaminated sea food.

These two factors facilitated an increase in the concentration of mercury in the air and water, which found its way into the body. according to a study carried out by Indian Institute of Technology, Hyderabad (IIT-H).

Hyderabad was selected as it was in the interior of the country with no specific local mercury source, Vasco da Gama, a city along the west coast, with no specific mercury source but probably more fish-eaters, and Nellore, a coastal city in Andhra Pradesh with several coal-fired power plants.

The study, which covered 668 volunteers, has been published in the Journal of Exposure Science and Environmental Epidemiology.

Hair samples of the respondents were used to assess their mercury levels. It found that 5.5 per cent of all the volunteers were found to have mercury levels higher than the prescribed maximum safe level i.e. 1.1 parts per million.

The researchers collected information on demography, body mass index, dietary patterns, professions and other variables from the respondents in these cities before analysing the amount of mercury in their hair samples.

While mercury in the hair is non-invasive, mercury enters the bloodstream primarily through breathing polluted air and consuming foods like fish, rice, and other foods cultivated in areas where untreated water is used for agricultural processes.

IIT-H researchers had hypothesised that those consuming seafood in large quantities would have higher levels of mercury in their bloodstream than the others, and their research has confirmed their hypothesis. Further, even the rice eaters in Nellore showed higher mercury levels, thereby pointing at the fact that untreated water is being used to cultivate rice in Nellore.

In addition to the above, goldsmiths, too, were found to have higher levels of mercury, which, in their case, can be attributed to the occupational inhalation of mercury vapour. Dr Asif Qureshi, associate professor, department of civil engineering, IIT Hyderabad, who headed the research team, said, “Non-occupational exposure to toxic elements through the food chain is increasing at an alarming pace. Coal-fired power plants happen to the largest contributing factors behind the increasing levels of mercury in our environment. The total mercury emission is estimated to reach 540 tons by 2020. Other than its neurotoxic nature, mercury is also found to affect the heart and lungs.”

Dr Qureshi did acknowledge the high nutritional value of fish and said that the government should issue advise on which fish to eat and in what quantities so as to minimise the likelihood of mercury poisoning. It is very critical for corrective steps to be taken in order to reduce the toxicity in our environment and to protect human health, he said.

Senior general physician Dr Govardhan Mandula explained, “A direct co-relation between mercury levels and disease is not drawn even during clinical examinations unless its severity is found to increase despite medication. High levels of mercury can lead to neurological and behavioural disorders. Blood tests are carried out when medication is found to be ineffective. If mercury levels persist despite treatment, however, then it can cause damage, sometimes even fatal, to the lungs.”