Facing the heavy metal challenge

To make matters worse for the Capital, mercury has emerged as the most alarming, disease-causing source of toxicity. Authorities need to implement a judicious combination of emission prevention and control measures to achieve an optimal reduction of mercury release

The national Capital of Delhi is not new to some of the worst levels of air pollution in the country with heightened concentrations of carbon dioxide and particulate matter ruling the roost. Now, to make matters worse, a variety of air pollutants are turning lethal, posing a never before threat to the human well-being. According to the findings of an experimental station being run by the Central Pollution Control Board (CPCB), the city’s air is also laced with toxic pollutants, such as mercury and formaldehyde.

Given this background, it now seems obvious that Delhi ended up earning the dubious distinction of becoming the most polluted city on earth in November 2017, after the city’s pollution level hit almost 30 times the World Health Organisation’s (WHO) safe limits.

Since there are no permissible standard sets in India yet for mercury, the CPCB has not stated if the levels being recorded at the station are too high or within the acceptable limit. But according to environmental experts, these pollutants, even at trace levels, present a deadly threat.

Mercury is considered to be highly toxic and is most detrimental to children and pregnant women that can cause developmental abnormalities. Mercury is, in fact, considered by the WHO as one of the top 10 chemicals or group of chemicals of major public health concern.

The WHO also states that inhalation of mercury vapour can produce harmful effects on the nervous, digestive and immune systems, lungs and kidneys and may lead to fatalities in extreme cases. The inorganic salts of mercury are corrosive to the skin, eyes and gastrointestinal tract, and may induce kidney toxicity if ingested. Even the United States Environmental Protection Agency has identified methyl mercury as a possible human carcinogen.

The bad news about mercury does not end here. Mercury is an element and, hence, it never breaks down. It evaporates readily and travels long distances in the atmosphere, causing local, regional and global pollution. Worse, the amount of mercury being deposited from the atmosphere today is three to four times as much as was deposited 150 years ago and the cause of this is man-made. About 30 per cent of mercury in the atmosphere comes from natural sources such as volcanoes or forest fires. But 70 per cent of the mercury is a result of human activities.

Evidently, stringent Government regulations are the only options to rein in this dangerous pollutant. Authorities need to practice zero tolerance on violations made by manufacturers of mercury-containing products. Additionally, Government programmes and solid waste management facilities can significantly reduce the quantum of mercury entering the environment from products that contain it.

The United States has set up a very successful example in containing and reducing mercury pollution. The Hennepin County, Minnesota programme, to keep mercury out of the waste stream, together with pollution control equipment on the county’s waste-to-energy plant, have brought mercury emission levels down from 496 pounds to less than 21 pounds which is a reduction of over 95 per cent. Examples such as these serve as a pointer to India on how to handle this emerging threat.

It is also critical for India to put control on coal-based power plants as they are one of the major sources of mercury pollution. Coal combustion residuals, commonly known as coal ash, are created when coal is burned by power plants to produce electricity. Coal ash contains contaminants like mercury, cadmium and arsenic.

Given the alarming presence of mercury in air, the Government must quickly revise and strengthen the regulations to reduce emissions of toxic air pollutants from coal and oil-fired power plants; this will have a positive cascading impact and provide relief and succor to beleaguered cities such as Delhi.  The tightened regulations, once in place, will induce the power plants to take steps such as installing controls or updating operations, which can protect public health.

The need of the hour is a well- thought-out combination of emission prevention and control measures in order to achieve an optimal reduction of mercury releases. The National Green Tribunal has established a blazing track record as a guardian of the environment and must now step in and examine the causes for the spike in mercury levels in the air we breath and ensure that the Government does the need full in not only setting up the required regulations but also implementing the same so that the people, especially the children and the elderly of Delhi and other cities in India can breathe easy.

(The writer is an environmental journalist)