|
|
|
The Mercurial Menace
More and more Indians today face the threat of being crippled by mercury poisoning. The
use of this deadly metal that plays havoc with human health is growing rapidly in India,
unfettered by any rules or regulations
Mercury, a heavy metal, is
used in a number of industrial applications and products. It is a highly mobile element
and cannot be broken down into harmless components. No mercury is actually consumed, so
whatever is used has to be discharged with effluents, wastes, air emissions or has to be
present in the products. As it is a highly mobile substance it continuously escapes in
traces, even from sludge buried deep within "secure" landfills, and companies
have no facilities to monitor this escape. More than 90 per cent of the mercury used in
industrial processes literally vanishes into thin air. Though elemental mercury is less
hazardous, its other forms, especially organic mercury compounds (when it combines with
carbon) such as methyl-mercury are more toxic.
Methyl-mercury, is the most common form of mercury found in the
environment. It can pass into the air, soil and the foodchain, mostly through aquatic
animals and can become a considerable health risk.
Presently, India is the largest user of mercury in
the world (207–531 tonnes annually). While the developed world has an effective
retrieval system and strict norms, India hardly has any regulation worth speaking of. In
India, there are no norms for controlling the use of mercury in various products.
Chlor-alkali industries are the major source of mercury release in the atmosphere and
surface water in India. Other contributors are coal-fired plants viz. thermal power
plants, steel industries and cement plants. Plastic industry (mercury is used as a
catalyst), pulp and paper industry, medical instruments and electrical appliances, certain
pharmaceutical and agricultural product account for additional consumption of mercury. A
draft notification was issued by the Ministry of environment and forests in 2000 for a
phased elimination of mercury from consumer products like caustic soda but so far no
action has been taken. The government may have banned the setting up of new mercury-based
caustic soda plants, but it does not have any concrete plans to phase out the existing
ones.
| India’s
industry continues to consume and emit mercury at alarming rates. |
According to the Canadian global
emissions interpretation centre (CGEIC), which has published data on the spatial
distribution of mercury emissions in air, India is one of the world’s mercury
hotspots, with mercury being released into the air uniformly at a rate of 0.1–0.5
tonnes per year, with coastal areas having an even higher emission rate ranging between
0.5 to two tonnes per year. According to the CGEIC, anthropogenic emission of mercury is
estimated to have increased in India by 27 per cent between 1990-2000. Clearly, mercury is
a major problem and action needs to be taken now.
Regulations compare poorly to those in developed countries
The Indian government has so far been unable to compile any
comprehensive data on all the uses of mercury in the country. There are some 3,000
industrial uses. Chlor-alkali industry is the single largest mercury consuming industry in
India, consuming about 55 tonnes of mercury each year. After the chlor-alkali industry,
the major consumption of mercury in India happens during the production of batteries,
thermostats, thermometers and barometers, and other electrical appliances such as mercury
vapour lamps, electrical switches and fluorescent lamps. As India does not produce any
mercury, it has to be imported. In 2002-03 India imported 531 tonnes of elemental mercury
and 1,312 tonnes of organo-mercury compounds. Nevertheless, it is important to mention
that this is probably an underestimation of the real picture as there is a thriving
illegal trade of the commodity. In developed countries, the use of mercury in various
products is either banned or regulated. However, no concrete initiative has been taken by
the government of India to address the issue. India is one of the very few countries,
which still allows the use of catalytic mercury compounds in industrial chemical
processes.
Unintentional
mercury releases
The mercury content in coal found in India ranges between 0.01 parts per million (ppm) to
1.1 ppm. A typical power plant emits 90 per cent of its mercury into the air and 10 per
cent to the land. The main reason for such a high rate of emission is that mercury boils
at low temperatures. Assuming the average mercury content in coal found in India to be
0.25 ppm, about 65 tonnes of mercury has been released every year between 1991–92 and
2000–2001 into the environment due to coal consumption alone, of which about 45.5
tonnes comes from thermal power plants. The thermal power plants account for 70 per cent
of the unintentional mercury emissions in India
Total annual mercury pollution in India |
| Average between 1991-92
and 2000-2001 |
| Sources
|
Mercury use (tonnes/annum) |
Mercury released (tonnes/annum) |
| Chlor-alkali Industry |
70 |
70 |
| Other mercury containing
products |
100 |
27.5–55 |
| Unintentional mercury
release due to coal use |
Nil * |
75 |
| Total |
170 |
172.5–200 |
| Southeast Asia |
5,730 |
7,423 |
| Source:
Anon 2003, calculations done by Green Rating Project, Centre for Science and
Environment (CSE), New Delhi. |
End-of-pipe treatment technologies can effectively control this
unintentional release (see
Table: Total annual mercury pollution in India). Unfortunately, the
issue of unintentional release of mercury has not even been identified by the government
as an environmental problem and therefore no initiatives have been taken to reduce the
risks.
Developed countries routinely use India as a dumping
ground for mercury
Two multilateral environmental agreements cover mercury and
mercury compounds: The Basel Convention on Control of Transboundary Movements of Hazardous
Wastes and their Disposal; and the Rotterdam Convention on the Prior Informed Consent
Procedure for Certain Chemicals and Pesticides in International Trade.
These instruments regulate trade in unwanted chemicals, pesticides and
hazardous wastes. However, they do not contain any specific commitment to directly reduce
usage and release of mercury. These loopholes are effectively exploited by multinational
industries, which virtually use developing countries like India as a dumping ground for
cheap mercury and outdated mercury technologies. Pure elemental mercury is not included in
the list. It is the mercury in pure form that is used as a raw material in a large number
of industries and this is one of the main reasons why even the Rotterdam convention does
not apply to mercury compounds with industrial uses. Only mercury wastes of various
categories are included in the Basel convention hazardous wastes list.
India growing as a mercury pollution hotspot
Mercury pollution is widespread in India, water pollution being the main concern (see Map: Some mercury
hotspots in India). This is a very serious problem and urgent steps need to be
taken to ban or severely restrict the usage of mercury.
The main reason for groundwater contamination in places like Gujarat
(Vatva, Ankleshwar and Vapi) and Andhra Pradesh (Patancheru, Medak) is the practice by
rogue industries of discharging untreated effluents into the ground through borewells.
Even contaminated effluent flowing through rivers and streams or rainwater percolating
through contaminated soil (at sites where toxic wastes are dumped or land-filled) can
leach into the groundwater. Rainwater also absorbs mercury vapours present in the
atmosphere.
Mercury has been detected in the water (groundwater and surface water)
in the vicinity of the chlor-alkali industries using the mercury cell technology and in
the vicinity of dyes, paints and pigments manufacturing units that use mercury-based
catalysts in their manufacturing processes.
To avoid a mercury disaster in the near future, industries using
mercury in its processes should immediately shift to non-mercury alternatives.
|
|
