Industrial sewage has been a major pollutant
 Mumbai:
The survey of coastal waters suggests that the influx of
industrial waste into inner estuarine zones—tidal areas where
the sea meets rivers—should be discouraged for new industries.
Stringent measures are also suggested for the treatment of
effluents that are presently released into the sea without any
controls.
The study, done by the National Institute of Oceanography (NIO)
for the Maharashtra Pollution Control Board (MPCB), warns of
heavy environmental degradation if the measures are not taken
seriously and immediately.
The study suggests that industrial effluents be emptied into
waterways at more downstream locations wherever a crisis is
observed. “In the case of existing discharges, a detailed
site-specific survey should be conducted to assess the ecology
of the estuarine segment receiving the contaminants. If the
results, particularly of pre-monsoon periods, are unacceptable,
the effluent release should be shifted to a suitable downstream
location in the estuary where assured dilution is available so
that the impact on the ecology is minimised,’’ the survey says.
The survey says the release of effluents meeting MPCB and
Central Pollution Control Board norms in
estuaries where tidal flushing is high, should be permitted only
after proper studies of pollutants and
the impact on the ecology. New industries should be persuaded to
release treated effluents deep into the open sea at specific
sites, as organic waste, particularly sewage, has been the major
contaminant in estuaries, creeks and coastal waters of the
state. The study says domestic sewage, if treated and
disinfected, is not harmful to aquatic life, provided its
release does not cause depletion of dissolved oxygen.
Hence, it is vital to assess the capacity of creeks and
estuaries to assimilate organic waste. It suggests analyses of
each creek and estuary in summer so that a plan can be drawn up
to protect the environment and have sustainable development.
SAVING THE SHORE: The Next Steps
Effluent releases to inner creek/estuarine zones should be
discouraged
For existing effluent discharges, a detailed site-specific
survey should be conducted to assess whether the water body can
assimilate the discharge
Existing effluent releases should be shifted downstream with
additional treatment as required
Effluent releases may be permitted in the lower estuary (closer
to the sea) only after asserting if the discharge can
assimilative with the water
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