Mapping the Scourge
India is a mercury pollution hotspot
Water contamination
Mercury pollution in water is widespread in India. This is a very serious problem and
urgent steps need to be taken to completely 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
industrial practice of pumping 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 in the atmosphere from far-off
sources.
| Mercury
concentration in fish and other species |
| Place |
Fish/other species |
Hg concentration in mg total
Hg/kg dw permissible limit: 0.5 ppm) |
Maximum value:no. of times or
higher than ppm (permissible limit |
Reference |
| North Koel river, Bihar |
|
|
600 — 700 |
‘Mercury concentration of fishes
in north Koel river’, Rehela (Palamau), Bihar, India. Indian Biologist, 23 (2)
(1992), 58-60 |
Mumbai, West coast,
Maharashtra
Sagar Island, East coast West Bengal |
Fish
Bivalves
Gastropods
Crabs
Bivalves |
0.03 — 0.82
0.13 — 10.82
1.05 — 3.60
1.42 — 4.94
0.06 — 2.24 |
1.6
21.6
7.2
9.9
4.5 |
Chemosphere, Vol. 33, 147-158
(1996),cited in Global Mercury Assessment, UNEP
Chemicals, 2002 |
| Binage, Karwar, Karnataka |
Oysters |
0.18 — 0.54 |
1.1 |
Heavy Metal distribution in the biotic
and abiotic matrices along Karnataka coast, West coast of India, Indian Journal of
Marine Sciences, vol. 27, June 1998, pp. 201-205 |
Mercury has been detected in the water (ground-water and
surface-water) in the vicinity of 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.
Methyl mercury intake through tainted fish
can put the population at grave risk, especially the newly-born |
|
Fish contamination
The coastal areas of India are significantly polluted with mercury and high levels of
mercury is being detected in Indian fish, both saline and freshwater. The Minamata
disaster was caused by consuming mercury-tainted fish. To prevent such a tragedy from
happening in India, people who eat fish need to be made aware of mercury contamination and
its implications.
Soil and sediments contamination
The level of mercury in soil is an indicator of its potential to contaminate rainwater and
groundwater. It also gives an indication of its contamination potential in crops and
vegetables grown in that soil. Soil contamination could be caused either by direct dumping
or land-filling of mercury-contaminated wastes or due to the presence of mercury in the
atmosphere. The level of mercury in water-body sediments is a representation of the
history of contamination in that water body. Minamata bay had to be dredged of toxic
mercury-contaminated sediments in order to restore the water quality.
From the map (opposite), it is clear that mercury
hotspots are distributed uniformly throughout the country. Due to the extremely mobile
nature of mercury, it is likely that there could be more hotspots. This needs to be
investigated by further testing of point sources such as smokestacks, ambient air, surface
and groundwater and contaminated soil from dumping grounds and landfills, and random soil
samples from other locations.
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