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Loretta Fernandez and her colleagues have been working on creating passive samplers that would allow them to locate old munitions by detecting degraded compounds in the water.
The two world wars that took place during — and in many ways defined — the 20th century left a legacy of trauma and devastation that’s echoed throughout the years. But the threat of those old weapons persists in the form of unexploded munitions, which litter many of the world’s oceans.
In the North and Baltic seas, the problem is so complex that German officials have deployed remote-controlled seabed crawlers and robots to remove old weapons that release toxic chemicals in the water. In recent weeks, Swiss officials began soliciting researchers for ideas to help them clean up munitions in deep lakes, offering a cash prize of $58,000 to the top three entries in a competition.
That’s where Loretta Fernandez, an associate professor of civil and environmental engineering and marine and environmental sciences at Northeastern University, comes in. Fernandez and her colleagues have been working on creating passive samplers that would allow them to locate these munitions by detecting degraded compounds in the water.
“There’s the explosive threat,” Fernandez notes, “like what happens if it comes up in someone’s fishing net and it explodes, because some of them are armed.”
And then there are the less obvious threats, like the environmental fallout from the chemical breakdown of munitions over decades. An explosive compound widely manufactured and used during World War I, trinitrotoluene (TNT), for example, has been shown to be toxic to human beings. When TNT-based explosives degrade, they release chemical byproducts that can harm aquatic ecosystems and pollute soil.
Other explosive compounds, such as cyclonite or hexogen (RDX) and octogen (HMX), are less well-studied, Fernandez says, but potentially just as hazardous.
She’s studying how those (and other) munitions compounds degrade.
“What we know less about is what they transform into and how toxic those degradation byproducts are,” she says.
Those toxic chemical corollaries, Fernandez says, affect different organisms in different ways. It’s a growing area of research that can help scientists and authorities determine how urgent the task of munitions removal really is in the world’s water bodies. Switzerland, for example, has been analyzing its lakes’ water and sediment for more than a decade to ensure that leftover munitions are not harming its fragile ecosystems.
“As they start leaching into the water, there have been a lot of studies looking at the toxicity,” Fernandez says. “Who are these components toxic to? How long do they last? How quickly do they degrade in water?”
Fernandez says based on the current understanding of the toxicity of the most common compounds (TNT and RDX), the risk to human beings at present is fairly low. That’s because those compounds degrade relatively quickly, she notes. In Swiss lakes such as Lake Lucerne, Lake Thun, Lake Brienz and others where munitions may reside, the concentration of harmful chemicals isn’t likely to reach the point where it would present a health threat to swimmers or residents.
The Swiss government has noted that in addition to “poor visibility and the risks of explosion, the water depth, the current and the dimensions as well as the condition of the submerged ammunition present a further challenge.”
Not all unexploded ordnances are armed or pose an explosive threat. But many are — and still do.
“The way that people have been disposing of these unexploded ordnances, if they’re armed — and you don’t know, unless you have a record of that one being dumped — is that they’ll go out and explode them in place,” Fernandez says.
Detonating munitions found in the water, however, can cause devastation to underwater life.
“If you’re a fish, that’s going to be bad,” she says. “There’s going to be this huge shock wave, and everything within the vicinity is going to die. So that’s not always a great option.”
In the U.S., unexploded ordnances tend to be clustered in coastal oceans, particularly in waters surrounding Hawaii and Guam. Vieques, an island in Puerto Rico that was a World War II-era naval base, is home to an alarming concentration of unexploded ordnances that have been found on land and sea.
Military officials there have removed hundreds of thousands of munitions on land, but haven’t yet begun to plumb the seafloor for remnant weapons.
During World War II, some 10,000 unexploded munitions were dropped on Guam, and the Department of Defense is still working to clear them out more than a half-century later.
“Some of them were dumped deliberately, and you can see when you look at pictures of the sea floor — there’s a trail,” Fernandez says. “You can see the direction the boat was going as they were pushing these things off the back.”
The scope of the problem is well-understood: military weapons from the old world are still omnipresent. As they age and degrade, new methods for monitoring and extracting those hard-to-reach munitions will be necessary.
“Other people are taking different strategies,” she says. “We’re taking a sniffing the water sort of approach.”