Unexploded ordnance has become a time bomb in the ocean

Mines and bombs left over from World War II pose a growing threat to marine life and coastal communities

David Adam

HONIARA/LONDON (DialogueEarth) – So many World War II ships and planes sank near Savo Island during months of conflict between the United States and Japan that this stretch of Pacific waters was named Iron Bottom Sound.

Decades later, the wrecks remain, as do the contents and cargo on board, including munitions, explosives and toxic chemicals from the fuel. As they corrode and leak in the deep waters of this archipelago of the Solomon Islands, chemicals such as heavy metals and hydrocarbons seep into the marine environment. These substances can pose a threat to surrounding ecosystems and even human health.

Iron Bottom Bay is just one example of a growing global problem. From Hawaii to the Baltic Sea, researchers are racing to understand the risks these munitions pose to the marine environment and what can be done about them.

Many of the munitions are deliberately dumped into the sea as a way to dispose of unused stockpiles after a conflict ends.“They’ve been dumping munitions into the ocean for a long time,” said Margo Edwards, director of the University of Hawaii’s Applied Research Laboratory, which has studied the issue.

The weapons have been there for almost a century, but now fishing and other marine activities, such as offshore wind power, are increasingly encroaching on those sites. As the munitions corrode, the risk of environmental contamination increases every year. “It’s a bit like our modern lives extending back to decisions made in the 1940s or even earlier that led to this conflict,” Edwards said.

Be prepared for disasters

In some cases, the ordnance is a well-known landmark. For example, the USS Richard Montgomery has been lying in the shallow waters of the Thames Estuary, about 50 miles east of London, since it ran aground during a storm in 1944. The wreck, whose masts are visible in the often choppy waters, carried an estimated 1,400 tons of unexploded ordnance. A 1970 assessment found that if the ship had exploded, it would have caused a tsunami large enough to engulf the nearby town of Sheerness.

But in many cases, the scale and exact location of underwater dangers remain unknown. Records have been lost or simply do not exist. Anxious sailors tasked with handling hazardous remnants often dump them overboard as quickly as possible.

For years, the problem has been ignored and neglected. But some experts say that’s no longer the right approach. The metal cans and boxes that hold the bulk of the dumped explosives have been gradually corroding, and now there’s a growing risk of leaks. If large amounts of explosives were to leak at once or in a short period of time, it could cause a serious contamination incident. At the very least, we need better investigations and monitoring to properly assess the level of risk, researchers say.

“All the mechanisms are ready for a huge environmental catastrophe,” said Jacek Beldowski, a geochemist who studies ocean-dumped munitions at the Polish Academy of Sciences’ Institute of Oceanology. “Everything depends on the rate of corrosion, and whether corrosion will occur simultaneously.”

Assessing environmental risks

The threat to the environment from unexploded underwater ordnance takes two forms.

The first is discarded chemical weapons, including mustard gas, used to produce the kind of poison that wreaked terror in the trenches of World War I. These gases and their breakdown products, such as arsenic, are toxic to marine life and accumulate in the bodies of fish and shellfish larvae.

The second is ingredients from conventional explosives, including TNT. These ingredients are known to cause cancer, so scientists cannot set a “safe” exposure level.

“Both are ongoing point sources of pollution on the seafloor and are releasing toxic components,” said Berdovsky, who has witnessed the conditions in the Baltic Sea firsthand.

“We have about 40,000 tons of chemical munitions in the Baltic region, and about 500,000 tons of conventional munitions,” he said. “If the chemical munitions are corroded, it’s easier to identify because you can see the explosive in the middle, which sprays the agent all around.”

There’s no doubt that toxic chemicals are being released, but that doesn’t always mean there’s a serious threat to the environment. It all depends on the concentration and how it affects marine life. That’s exactly what Edmund Mather, a toxicologist at the University of Kiel in Germany, is trying to find out.

Mather conducted experiments in the Baltic Sea, exposing mussels to corrosive mines laid by the British Navy in the 1940s and to fragments of TNT that fell from the mussels. After three months, they found that mussels near the fragments had absorbed 400 times more TNT and its derivatives than mussels near intact mines.

Mather said this suggests the risk of environmental contamination will rise dramatically as munitions corrode.

“If we wait too long, all of these bombs, mines and torpedo heads will lose their protective metal casings. That will give the explosives a greater surface area, and then we’ll have a higher rate of dissolution into the environment.”

Fishing is prohibited in the Baltic Sea where munitions depots are known. But research by Mather’s lab shows that mussels farmed elsewhere, including in the North Sea, are beginning to show similar signs of contamination. Mussels collected in the 1980s contained no toxins. “The first signs of munitions chemicals appeared in 2000. Starting in 2012, we have clear signs of these chemicals,” Mather said. He stressed that concentrations of these chemicals are still low but will continue to increase.

Mr Mather said action needed to be taken now before the situation deteriorated further. “We should start remediation now to prevent further corrosion and prevent further contamination of the marine environment.”

Who should solve this problem?

Securing the munition or removing it from the sea is a difficult task. Disturbing the site could cause an accident and cause the metal casing to disintegrate further. Controlled explosions have been carried out in the past, but this only spreads the contamination over a larger area.

There is also the question of who should be held responsible. David Alexander, a professor of emergency planning and management at University College London, has studied the risks posed by the SS Richard Montgomery in the Thames. He noted that efforts to make the wreck safer were complicated by the fact that it was an American ship in British waters.

“The US government offered to take steps to address this problem (in 1948 and 1967), but the British government said ‘no thanks’,” he said.

The issue of responsibility is particularly acute for Pacific Islanders, including those in the Solomon Islands, who have effectively inherited someone else’s problems. Lindsay Cottrell, environmental policy officer at the Conflict and Environment Observatory, noted that the United States and Japan have worked alongside international nongovernmental organizations to remove munitions from places like Palau.

Currently, the work focuses on munitions left behind on land, where they pose a greater threat to local residents, but Cottrell said the work must be extended to sea.

“Palau and the Solomon Islands are highly dependent on tourism and diving. Solving this problem is critical,” she said.

Next year will mark the 80th anniversary of the battle that gave Ironbottom Sound its name. The problems it created are still to be resolved… PACNEWS

David Adam is a freelance journalist based near London

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