Industrial sewage has been a major pollutant …….Chittaranjan Tembhekar
Mumbai: The survey of coastal waters suggests that the influx of industrial waste into inner estuarine zonestidal areas where the sea meets riversshould 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