Mercury
Pollution: Indian Scenario
Drinking
water standards for mercury
The Bureau of
Indian Standards (BIS) has laid down safety limits for drinking water at 0.001
mg of mercury per litre. A number of samples of groundwater in some industrial belts
have shown concentrations of mercury higher than safe standards. A study shows
levels of mercury to be very high as compared to the permissible limit. The
table above shows the critical geographical areas.
In India, some of
the major rivers tested for heavy metals by the Industrial Toxicological
Research Centre (ITRC), Lucknow, were found to contain mercury in alarming
levels. Testing of seawater by the National Institute
of Oceanography, Goa, found increased mercury concentrations in the Arabian
Sea. Several studies on fish and prawns in Mumbai,
Kolkata, Orissa, etc, have reported alarming rates of mercury concentrations.
Recent studies have shown that the total mercury pollution potential from coal
in India is estimated to be 77.91 tonnes per annum, if average concentration of
mercury in coal is assumed to be 0.272 ppm. About 59.29 tonnes of mercury per
annum is mobilised from coalfired thermal power plants alone. The
five super thermal power plants in the Singrauli area, which supply 10 per cent
of India’s power, are responsible for 16.85 per cent or 10 tonnes per annum of
total mercury pollution through power generation.
The Paryavaran
Suraksha Samiti (PSS) collected samples from over 20 villages affected by
industrial pollution in the Golden Corridor of Gujarat to investigate the water
situation
there. The samples
were analysed for Mercury and Chemical Oxygen Demand (COD). In
Haria village and
Atul Complex, mercury was shockingly high at 12 ppm – 1200 per cent
more than the
permissible limit of 1 ppm. Another sample in Ankleshwar showed mercury at a
high level of 2 ppm which is 200 per cent above the standard. Samples in
Vadodara-Nandesari ECP Area also showed high mercury levels at 6 ppm and 1.3
ppm, which are 600 per cent and 30 per cent more than the prescribed standards,
respectively.
The People’s
Science Institute (PSI) in Dehradun has recently found high levels of mercury
in the groundwater sources of Bhopal, especially near the Union Carbide
factory. The water is dangerous for human consumption as the area of
groundwater contamination is increasing. Water samples from various localities
taken for testing showed that contamination levels in some places were as high
as 2 ppm. A recent study conducted by the Environmental Science Department of
the Guru Gobind Singh Indraprastha University, Delhi, reveals that the
concentration of contaminants like arsenic, mercury, nitrates, etc, in the
groundwater of Delhi exceeds the permissible limits. The study entailed 50
samples of groundwater being lifted from random spots along a 22-km stretch
between Palla and Okhla. The mercury concentration in some samples was as high
as 4.6 ppm, 460 per cent above the permissible limit. This alarming presence of
mercury in groundwater can be traced to the continuous discharge of sewage and
industrial effluents into the Yamuna and, subsequently, into the groundwater
aquifer which, being sandy in nature, allows mercury pollution to spread at a
rapid rate.