The environmental risks of World War II wrecks

Over 8,000 military and civilian ships sunk during World War II may soon begin releasing the contents of their tanks into the sea. An environmental disaster of proportions …

Here is the most dangerous bomb of World War II

At the bottom of the oceans there is an ecological bomb over 60 years old ready to explode, an environmental device so powerful it makes the Deep Water Horizon disaster seem little less than a firecracker: they are the fuel tanks of the more than 8500 sunken ships during the Second World War in the seas around the world. And among these more than 1500 oil tankers. The alarm from the columns of the NewScientist weeks are Trevor Gilbert , of the Australian Maritime Safety Authority and Dagmar Etkin of the Environmental Research Consulting in New York, who together with a group of colleagues have created the first database in the world of potentially war wrecks. dangerous.

Postwar Ecocatastrophe

Almost 70 years after the sinking, the salt water has corroded the plates of the ships to the edge of the seal and the tanks of many wrecks are beginning to leak. “There is evidence that many sunken vessels off the coast of the United States are on the verge of releasing fuels, lubricants and all sorts of dangerous substances into the water,” says Etkins. “Doing nothing and waiting is a possibility, but it’s a desperate attempt,” echoes Ian MacLeod, of the Australian Maritime Museum who has already worked on many wrecks. “Over the next 5-10 years we should expect a substantial increase in fuel outcrops from war wrecks that will last at least the next half century.” But how much fuel is there down there? “Calculating it exactly is very difficult,” the researchers explain, “the loss of Exxon Valdez .

And the confirmations of what the technicians say are already there: in 2001 the American military tanker US Mississinewa, which sank between the islands of Mirconesia on November 20, 1944 with over 20,000 tons of oil and aeronautical fuel, began to pour into the sea the contents of its cisterns. After 57 years of quiet a typhoon moved the wreck a few meters: it was enough to crack the metal sheets and cause the contents to spill onto the surrounding white beaches. According to experts, the sea “eats” about one millimeter of sheet metal every 10 years, but it is impossible to generalize: each wreck is a case in itself.

Just a hole that guarantees better oxygenation of the water and corrosion becomes much faster. And at the same time, the colonies of marine organisms that grow on the sheets can help improve the tightness of the entire structure. Inspecting and checking is therefore the only possible way.

Who pays? But once the potentially dangerous wrecks have been identified, how can we intervene? One of the most used techniques for emptying tanks is hot tapping. Holes are made in the tanks and the contents are heated with thermal lances to decrease their viscosity, then everything is pumped to the surface. However, the intervention is very expensive: in 2001, emptying the tanks of the Jacon Luckenbach, which sank in 1953 off the coast of San Francisco, cost 15 million euros. To save time, it is also possible to attach a sacrificial anode to the walls of sunken ships: a metal plate that alters the electrochemical properties of the surrounding water, stopping the corrosion process. Not only that: raising the PH levels favors the growth of marine deposits on the surface of the wreck (it is called “sacrificial” because the metal plate that acts as an anode wears out over time). It is certainly not a definitive solution but it does help to save some time. The next priority will be to intervene on the wreck of the Coimbra: an English tanker torpedoed in 1944 by a German Uboot off the coast of New York: it was carrying over 11,000 tons of lubricants that have been polluting the waters of Long Island for years. For this reason, the NOAA (National Oceanic Atmospheric Administration), together with other governmental and non-governmental organizations, managed to obtain from Congress 1 million dollars to finance a project that studies the problem and the possibilities of intervention in an organic way. The hottest issues are, however, more economic than technical: in 1999 Etikin had estimated between 2,300 and 17. $ 000 per ton the cost of remediation, depending on depth. And the poorer nations, for example Micronesia, cannot afford it.