Environment - Will the Costa Concordia become an oil-spill disaster?

Pollution busters (Image: AGF/Rex Features )

Work is finally under way to begin pumping oil from the stricken Costa Concordia cruise liner. The vast ship ran aground and capsized off the Italian island of Giglio on 13 January. At least 16 people died and the search for bodies continues. Attention is now turning to the vessel's fuel, which could pollute the sensitive marine environment.

What are the risks to the environment?
The worst-case scenario is quite serious, as the Costa Concordia has run aground in the Pelagos Sanctuary for Mediterranean marine mammals, a protected area established in 2002 to safeguard species like fin whales and striped dolphins.

However, so far it looks as if an oil spill can be averted.

What is at risk?
The area has a rich marine ecosystem, and many local communities rely on fishing to sustain themselves when the tourist trade is slack. There are also several nature reserves and a national park on the coast of the nearby Italian mainland.

All this is threatened by the ship's fuel: about 2200 tonnes of heavy fuel oil and 185 tonnes of diesel, held in 17 tanks. Both fuels contain toxic compounds, says Nancy Kinner of the University of New Hampshire in Durham. Animals that ingest them may die, or suffer long-term harm that affects their ability to reproduce.

The fuels can also coat animals, just like crude oil. They will then struggle to retain heat, and so risk hypothermia.

What is being done?
A Dutch salvage company called Smit has been hired to remove the Costa Concordia's fuel. They began work yesterday morning and the operation is expected to last several weeks.

Smit plans to mount a control valve on the underside of the ship's hull. Beneath the valve, they will then drill through the hull into the chamber that houses the fuel tanks. They will pump the fuel out of each tank in turn, through a hose.

Isn't there a risk that the ship will move?
The Concordia is resting in two places on a submerged rock formation, which is holding it in place. It's unlikely, but stormy weather could destabilise it and cause it to slide into deeper water. This would lead to a fuel spill if pumping was under way at the time, or if the fuel tanks broke as a result.

Smit's spokesperson Martijn Schuttevaer says that the company's monitoring systems have not detected any significant movement in the last two days. Additionally, the company has run calculations based on the ship's mass, the amount of friction with the rocks, and the potential size of waves in the area. Results suggest the Concordia is stable.

 

Is it going to be an ecological disaster?
Only time will tell, but Smit seems confident that it won't be. The company has installed a double boom to contain any oil that does escape, and there is also an oil removal ship on the scene. These precautions were requested by the Italian authorities, but the company does not expect to need them.

The fact that the fuel is stored in many small tanks, rather than one big one, also reduces the risk of a major spill. Smit will pump only a small number of tanks, possibly just one, at a time. That means if anything goes wrong, only a fraction of the fuel could escape.

Kinner says that although the ship's location so close to shore increases the risks, it also makes the salvage operation easier. "It's bad," she says, "but there are things that make it easier."

http://www.newscientist.com/