MICHEL MARTIN, HOST:

By now, the world knows that Russia's invasion of Ukraine has devastated parts of the country, killed hundreds of thousands of people and displaced millions more, and destroyed huge swaths of critical infrastructure. And many people also know that the invasion has affected food supplies around the world since Ukraine was the breadbasket of Europe. But what many people might not know or have focused on yet is that these effects may last for years. As a result of the weaponry used, the toxic remnants of the war can indefinitely change the agricultural landscape of the country.

Joe Hupy has studied this. He is a digital soil geomorphologist in aviation and forestry at Purdue University. He's tested and analyzed the soil in Vietnam and areas of France that were affected by the world wars. And he's with us now to tell us more. Professor Hupy, thanks so much for joining us.

JOE HUPY: Yes. Thank you for having me on the show.

MARTIN: Soil tests performed by scientists found high concentrations of toxins like mercury, arsenic and other pollutants that, you know, we assume are byproducts of the war in Ukraine. It's my understanding that these tests show that these toxins are in millions of acres of farmland and forests. Can you help us try to understand the scope of the long-term issues that Ukraine farmlands could be facing?

HUPY: The same soil that's extremely fertile is also a soil that is going to cling on to a lot of these toxins following the war. And even though we're kind of winding back to stalemate conditions like we had in World War I, we have much, much more modern munitions. We have cluster bomblets that can linger around and degrade, and we also have depleted uranium rounds. And we have explosives that have a lot more different types of chemicals in them than we did in the past.

MARTIN: That sounds very dire. And so I guess the question now is, is there any way this can be fixed? I mean, is there any way this can be - that these harmful effects can be reversed?

HUPY: I mean, yes. And if we look at this, you know, such as with other wars, one of the things that you would see is that in Vietnam, in France, on the Verdun battlefield is that there are areas that are much more heavily disturbed than in others. And a lot of this comes down to where the stalemate conditions were and proximity to water table, how much clay you have in the soil. And a lot of that is just going to relate to, more or less, a lot of the tools that Ukraine uses right now in waging warfare, such as the drones that can take high-resolution imagery on demand. Following this war effort, those same pieces of technology can be first used to assess the amount of damage. But then, with the right sensors on board, you can monitor areas where you have stress in the crops, where you have stressed conditions, and those areas can be pinpointed to address the mitigation efforts.

MARTIN: But I guess the question I have is, like, how long does that take, assuming that at some point, hopefully, this conflict comes to an end?

HUPY: I wish I knew the answer to that. But what's really interesting is if we look at one of the largest acute high-magnitude disturbances rendered by humans, it occurred in Ukraine, and that's Chernobyl. And, in fact, one of the issues is that in Ukraine, where the Russians were around Chernobyl, there were many reports of them being forced to dig trenches in contaminated soils and kicking back up the same radioactive contaminants that were supposed to be left lying in place. But if we look at something like Chernobyl and we look at what is now one of the most diverse ecosystems out there, because of the lack of human impact, we might be able to kind of look at this and say, the vestiges of this war are going to last for a very long time. And if we look at the impacts of this war, we don't want to just think about the chemical contaminants in the soil.

One of the biggest issues that we're going to see here is that you have trenches crisscrossing the eastern portions of this war. In the eastern portions of Ukraine, where these stalemate conditions are, those trenches are probably going to linger for a long time because in many cases, it's not going to be that easy to plow them over. In those trenches, you're going to have a lot of stored munitions that might be left behind. You have issues from heavy vehicles and tanks going through areas when they were quagmired in mud. And then, of course, you had munitions storage. And so those areas, I would say, are going to last for a very, very long time.

All these unexploded shells, that's one of the saddest and most apparent vestiges of war. And when we think of the chemical contamination, a lot of that can and will be leached out through time in the order of maybe 10 years, 20 years, 50 years, in some cases up to a hundred years. But that'll go away. But if we think about the vestiges of war in terms of unexploded shells, in France, there are still tractors that are hitting unexploded shells and blowing up tractors. There are still stacks of unexploded shells on the sides of fields from farmers having to get out and physically remove them. And what we'll see in Ukraine is - unfortunately, we're going to see a lot of people getting killed or injured in the years afterwards from all of these forgotten unexploded shells.

MARTIN: That is Professor Joe Hupy. He teaches at Purdue University, and he joined us to talk about the toxic substances accumulating in Ukraine, especially on their farmland. Professor Hupy, thanks so much for talking to us about this.

HUPY: Thank you so much for having me. Transcript provided by NPR, Copyright NPR.