Calcutta, May 16: The several thousand tonnes of soda ash or sodium carbonate — in the hold of the sunken cargo ship Sigitika Biru — spells doom for marine life in its immediate vicinity where the ship ran aground last evening after developing a leak.
The 150 tonnes of diesel in the ship’s fuel tank also poses a major hazard. The oil slick that could result if the fuel escapes will also affect the marine environment unless it is contained and recovered.
The coast guard has called in one of its Dornier aircraft to make a disaster possibility assessment of the area around the sunken ship.
According to experts, the soda ash, if exposed to sea water, will dissolve causing the environment to become highly alkaline. “This will kill all marine life in the vicinity — fish, invertebrates and even the minuscule phyto-plankton that is a source of food for many marine animals,” said Dipak Chakraborty, the chief scientist of the state Pollution Control Board.
Being highly soluble, the chemical will, however, have an adverse effect on marine environment for a short period. The change in the tide will also cause it to dissipate and further dilution will make it disappear. “The turbulence and the changing tide will solve the problem of pollution over a short period, though it remains to be seen how much of sodium carbonate the vessel was carrying and how much damage has it caused to contaminate the area,” Chakraborty added.
Soda ash is a white, odourless, granular substance used in a wide-range of industries like glass manufacturing, metal refining, detergents, polymer production, tanning and cement among other manufacturing processes. Ironically, sodium carbonate is also used for effluent neutralisation and water purification.
Saying that all coastal pollution matters were handled by the coast guard, a senior board official said: “The organisation has equipment to tackle events such as oil spills and at best they send a report to us and the Central Pollution Control Board (CPCB).”
Regarding the oil spill, the experts pointed out that the vessel was almost at the end of its voyage — from Porbandar in Gujarat to Chittagong in Bangladesh — and that most of the fuel on board to run its engine and generators had been used up, minimising the chances of environmental damage.