What impact will the Costa Concordia disaster have on the environment?

Now that the search-and-rescue teams trying to find survivors in the wreck of the Costa Concordia have signalled that the operation is moving into the "recovery" stage, there is growing concern about the environmental impact that the half-submerged ship might have on the local coastline.

Sergio Ortelli, the mayor of the small Tuscan island of Giglio where the cruise ship grounded last Friday, said on Monday that "this is an ecological timebomb". The area is a well-known tourist destination where diving is a popular past-time. One diving website describes the waters off Giglio as "one of the most beautiful and fascinating" diving sites in the Mediterranean. With an estimated 2,380 tonnes of fuel on board, the race is now on to secure the ship – it is believed to have slipped on the seabed on Monday from a ledge 15-20 metres under the surface towards a far deeper channel – and prevent any fuel or other pollutants from escaping.

Booms have already been placed on the surface around the stricken ship to try to minimise the damage caused by any fuel spills and the local coastguard has already instructed Costa Crociere, the ship's owner, to remove the ship. Smit, a Dutch salvage firm, has been hired to remove the fuel from the 114,500-tonne ship and has said it will start the procedure "within days".

Agence France-Presse has more details:

A representative from US-based Titan Salvage said the [Smit] contract could run into the millions of euros.
"They've been phenomenally lucky there's been no spill. If the hole in the hull had been four or five metres further along it would have punctured the tanks," he said.
"It's very close to the edge of much deeper water," said the man, explaining that the waves could push it off its resting place and it could sink entirely.
The fuel pumped out of the ship will be replaced by water in the tanks to ensure that the ship remained stable in a practice known as "hot tapping".
[Italy's] environment Minister Corrado Clini meanwhile said that the environmental risk has been "our nightmare."
"The vessel has reservoirs full of fuel, it is a heavy diesel which could sink down to the seabed, that would be a disaster," he said.
In a worst-case scenario, the fuel could "leak into the sea, contaminating an exceptional coastline and affecting marine and bird life," he warned.
"We are ready to intervene if there is a spill," Clini said. "As soon as possible, the fuel will be removed from the vessel. But we have to take into account the precarious state of the ship."

Pier Luigi Foschi, Costa Crociere's chairman, told the media on Monday that, once the fuel was removed, the plan was to refloat the ship then tow it away for possible repairs and reuse. But, he added, if that fails then the ship would have to be cut up for scrap, a process that could take months, even years, as proved the case (admittedly, a very different scenario) with the salvage of the MSC Napoli off the Dorset coast in 2007. [more The Guardian]