CHENNAI:It has been 10 days since the oil spill played havoc in the bay. The Coast Guard on Tuesday claimed that the clean-up has entered the final lap and Dornier aircraft were deployed to ensure there are no traces of oil in the sea.
However, ecological concerns still loom large.
Experts say the damage done is irreversible and the high dose of chemical dispersants sprayed only adds to the problem.
The Coast Guard has sprayed about 2,700 litres of oil spill dispersants that are non-degradable. Dispersants generally serve to decrease the interfacial surface tension of oil, thus facilitating its weathering under low-energy conditions. However, in order to neutralise one threat, another environmental hazard cropped up as most dispersed oil remains in the water column where it mainly threatens pelagic and benthic organisms.
In Chennai oil spill case, the pollutant being Heavy Furnace Oil (HFO) or Bunker oil with high viscosity, dispersants typically don’t work unless a huge quantity is dumped.
“I feel the Coast Guard has hurried the process of use of dispersants. The vessel that leaked the bunker oil has done great harm by not telling the quantity and the nature of oil and the use of dispersants in high dosage has just worsened the ecology safety parameters. The Tamil Nadu Pollution Control Board (TNPCB) should conduct an environment impact assessment study,” Banwari Lal, senior director, The Energy and Resources Institute (TERI) told Express.
During the recent hearing at the National Green Tribunal (NGT) here, TNPCB counsel agreed that the dispersants proved to be ineffective.
Lal said TERI was part of Mumbai oil spill
clean-up and remediation process in 2010, which was the biggest incident in terms of quantum of oil spillage and in that case dispersants were used to minimum effect.
In response, Coast Guard officials said it’s like one has to decide which the bigger evil is. “If left unattended, the surface oil will decompose and pose the greatest threat to shoreline,” Deputy Inspector-General of Indian Coast Guard (Eastern) MA Warsi, who is the chief coordinating officer for the
operations, said.
He said that dispersants were used in deeper waters where the depth is greater than 10 metres.
Also, they were sprayed in accordance with the international standard norms and Tamil Nadu Pollution Control Board was kept in the loop.
“I have strictly instructed the ground teams not to use any chemical-based dispersants in shallow waters close to the shore. There was a meeting held on Tuesday wherein it was decided to rope in Indian Institute of Technology (IIT)-Madras and other research institutes to study a few dispersants suited for spraying in shallow waters. Once, that is done it will be tried in a smaller area to begin with,” he said.
However, sources in Tamil Nadu Pollution Control Board confirmed that dispersants were used in shallow waters too, but failed to yield any results.
No trace of oil up to 40 miles into the sea
Coast guard officials said Dornier aircraft were deployed on Tuesday and no trace of oil was found 40 miles into the sea along the coast. “We are mapping the entire coast to ensure there are no chances of oil spill escaping into the deep sea and left unattended,” an official said.
Meanwhile, DIG Warsi said the clean-up was now being monitored by the district administration and Kamarajar Port. “We have mobilised the resources and cleaned-up most of the beached oil deposits. The work is progressing in RK Kuppam where the pollution is restricted to 20-30 metres area. Steam wash is being given to the rocks,” he said.
Officials are also likely to use skimmers to pump out oil into buckets rather than manually mopping the coast. The skimmer technology was provided by Alpha Mers Bangalore. “We are using a funnel shaped skimmer which is connected to a pump and a generator.
The skimmer will suck the oil and it will be pumped out into the drums, said an official of the company, which is specialised in clearing spills.