The Soil and Superfund Sites Beneath Us: The Chemistry of Pollution, Episode 3

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<v SPEAKER_06>This is Chain Reaction, a podcast from the American Chemical Society, where we link chemistry's past to its future.

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<v SPEAKER_06>I'm your host, Marg Wall, and I'm Sam Jones.

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<v SPEAKER_01>Find your way to the real America.

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<v SPEAKER_01>And then find a surprise.

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<v SPEAKER_01>The Town Dump.

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<v SPEAKER_01>Burning one moment, smoldering the next.

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<v SPEAKER_01>A reminder that ugliness can be anywhere.

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<v SPEAKER_01>Open dumping is a health hazard.

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<v SPEAKER_06>Oddly cheerful music at the end there from this EPA production from 1972.

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<v SPEAKER_06>But the point is, Sam, for a long time humans have grappled with where to put their waste.

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<v SPEAKER_06>I mean, especially now that there are so many of us.

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<v SPEAKER_06>Yeah.

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<v SPEAKER_06>And of course, the problem is even more serious when the waste to be disposed of is toxic.

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<v SPEAKER_06>Say the waste of a factory with hazardous byproducts that can volatilize into the airstream or leach into the groundwater.

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<v SPEAKER_06>Let me tell you a story, Sam.

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<v SPEAKER_06>Please do.

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<v SPEAKER_06>Okay, so in the late 1800s, this guy, William T.

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<v SPEAKER_06>Love, decided he wanted to start a new town in Niagara Falls, New York.

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<v SPEAKER_06>And he figured if he built a canal that routes water from Niagara River to this town, the town could have a cheap source of hydroelectric power.

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<v SPEAKER_06>But after running out of money, he abandoned the project, leaving a large ditch called Love Canal.

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<v SPEAKER_06>Decades later, the Hooker Electrochemical Company used the canal to dispose of over 20,000 tons of chemical waste with governmental permission.

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<v SPEAKER_04>Love Canal is a, I would say an ironic name for a canal that's filled with waste.

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<v SPEAKER_04>Yeah, definitely.

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<v SPEAKER_06>So at some point, this canal, it's full of waste.

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<v SPEAKER_06>The company covers the canal with soil and then sells the land to the Niagara Board of Education for one dollar.

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<v SPEAKER_06>A school ended up being built on the property, and houses popped up around it, so this was like a nice little neighborhood.

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<v SPEAKER_06>But homeowners had reported weird smells, rashes, residues left in basements after flooding.

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<v SPEAKER_06>Some reported birth defects and new ailments.

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<v SPEAKER_04>That's awful.

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<v SPEAKER_04>I'm like kind of shocked that I had never heard about this before.

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<v SPEAKER_04>I looked it up because I was like, I've heard of a movie with the name Love Canal in it.

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<v SPEAKER_04>Yeah.

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<v SPEAKER_04>And there's one called Lewis Gibbs and the Love Canal.

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<v SPEAKER_04>We should watch this movie.

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<v SPEAKER_04>Yeah, no.

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<v SPEAKER_04>I was so curious.

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<v SPEAKER_06>Anyways.

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<v SPEAKER_06>So the state didn't confirm that chemicals were leaching from the Love Canal site into the groundwater until the 70s, when they found numerous toxic chemicals adjacent to the canal.

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<v SPEAKER_06>President Jimmy Carter issued an emergency declaration to get funds to start cleaning up the site and relocate residents closest to the Love Canal.

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<v SPEAKER_06>Wow.

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<v SPEAKER_06>Yeah.

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<v SPEAKER_06>So this actually spawned a new law in 1980 called the Comprehensive Response Compensation and Liability Act.

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<v SPEAKER_06>But you may know it by another name, the Superfund Act.

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<v SPEAKER_06>And Love Canal became one of the first official Superfund sites.

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<v SPEAKER_04>So I have heard of Superfund sites before.

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<v SPEAKER_04>Centuries ago in graduate school, actually, I don't know, like 10 years ago, one of my lab mates was working on a project related to arsenic.

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<v SPEAKER_04>And she was given funding by the NIH's Superfund Research Program.

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<v SPEAKER_04>But still, my understanding of superfunds is super limited.

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<v SPEAKER_06>Well, a superfund site is essentially just an area that has been designated by the government as having troubling amounts of hazardous materials.

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<v SPEAKER_06>Then either the responsible party, the polluter, has to pay for cleanup under supervision of the EPA, or the money comes from that superfund, which is a collection of money from different tax revenue streams.

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<v SPEAKER_04>So unfortunately, it does seem like this environmental disaster was a turning point that was needed to take land pollution more seriously.

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<v SPEAKER_06>Yeah, it was one of a few.

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<v SPEAKER_06>And when reading about this story, I got pretty curious about how you would determine that land or soil is polluted, how far you determine like a pollutant will spread, and how long it'll take to break down in different environments.

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<v SPEAKER_06>So I chatted with Owen Duckworth, a soil scientist at NC State University.

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<v SPEAKER_06>He started by explaining some of the basics of soil chemistry.

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<v SPEAKER_02>So soil chemistry is a study of how things move and react in soil.

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<v SPEAKER_02>So the composition of soils, properties of soils, chemical reactions that happen in soils.

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<v SPEAKER_02>It's got a lot to do with how sort of nutrients and contaminants and other important things move and behave in soils.

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<v SPEAKER_06>And why is it important?

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<v SPEAKER_02>So soils are super important because they're the interface between us and the earth, right?

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<v SPEAKER_02>We're walking around on them, they're very familiar to us, but we don't we don't think about them that much.

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<v SPEAKER_02>But the most obvious reason that they're important is that most of the food we consume comes from soils, right?

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<v SPEAKER_02>It's grown on it or it's grown and then fed to animals.

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<v SPEAKER_02>Also, it has a lot to do with the water we drink, right?

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<v SPEAKER_02>So more water moves through the roots of plants than moves through rivers to the ocean, which is kind of a shocking statistic.

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<v SPEAKER_02>Yeah.

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<v SPEAKER_02>The stuff that doesn't do either tends to go into the ground, and groundwater is a more important resource than ever nowadays worldwide for people to use for domestic water sources.

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<v SPEAKER_02>So soil is incredibly important.

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<v SPEAKER_06>Yeah.

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<v SPEAKER_06>Why is it so complicated to study?

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<v SPEAKER_06>Well, you know what?

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<v SPEAKER_06>I I'm assuming it's complicated to study.

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<v SPEAKER_06>I don't know.

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<v SPEAKER_06>Is that true?

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<v SPEAKER_02>Aaron Ross Powell, you're right.

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<v SPEAKER_02>Soil scientists like to say that soil is the most complicated thing that we know about in the world.

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<v SPEAKER_02>That's up for debate, of course, right?

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<v SPEAKER_02>Like neuroscientists have their own things, and I'm sure you know rocket scientists and people like that, but we got our thing too.

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<v SPEAKER_02>Every chemical element that's naturally occurring has been found in soil somewhere on the earth.

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<v SPEAKER_02>There are more than a billion bacteria in a teaspoon of soil.

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<v SPEAKER_02>So there's a tremendous biodiversity.

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<v SPEAKER_02>More than half the species of organisms live on our live in the soil.

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<v SPEAKER_02>That's wild.

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<v SPEAKER_02>It's a really complex system, right?

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<v SPEAKER_02>It's a it's the interface between minerals and and organics that are in the soils and organisms.

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<v SPEAKER_02>It's a really just rich thing to study.

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<v SPEAKER_06>Yeah.

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<v SPEAKER_06>And also I guess like it's full of solids and water too and air.

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<v SPEAKER_02>Yeah, it's got all the phases in it.

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<v SPEAKER_02>Yeah, well, no plasmas, hopefully.

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<v SPEAKER_02>But solids, liquids, and gases.

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<v SPEAKER_02>Yeah.

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<v SPEAKER_02>And they're all changing with time, right?

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<v SPEAKER_02>Because if you think about it, when it rains, water comes in, it completely changes the chemistry and all the reactions, and then it dries out again, and you can continue with these cycles and changes continuously.

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<v SPEAKER_06>So then how do you go about studying soil?

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<v SPEAKER_06>What kind of instruments do you use?

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<v SPEAKER_06>What do you do to it?

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<v SPEAKER_02>Trevor Burrus, Jr.: Well, lots of people study it in different ways, right?

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<v SPEAKER_02>We usually think about problems with sustainability and public health.

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<v SPEAKER_02>So we look at the cycling of nutrients in soils and how contaminants move and how people might get exposed to contaminants in soils.

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<v SPEAKER_02>So we try to tailor the approach to what we need, but we use a lot of x-ray techniques because x-rays are really special.

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<v SPEAKER_02>The wavelength of them is about the wavelength of an atom, so they see things at the atom scale.

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<v SPEAKER_02>And the way that X-rays interact with matter is often specific to elements.

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<v SPEAKER_02>So if we have all this complexity in soils where we have potentially every naturally occurring element on the periodic table, we need to cut out some of that and focus on one thing at a time.

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<v SPEAKER_06>I'm imagining like a laser gun or like one of those things that the aliens have, a beam coming out.

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<v SPEAKER_06>What does it actually look like?

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<v SPEAKER_02>Aaron Powell There's two different things that we use a lot.

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<v SPEAKER_02>So one of them is called a synchrotron.

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<v SPEAKER_02>And that sounds very cool.

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<v SPEAKER_02>It is.

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<v SPEAKER_02>It's a government facility run by the Department of Energy.

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<v SPEAKER_02>And there are maybe four or five big ones in North America, depending on how you count them.

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<v SPEAKER_02>And it's a giant ring that you I mean, by big I mean you you walk around and it's, you know, it takes you ten minutes to walk around in terms of size.

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<v SPEAKER_02>And what it does is it accelerates particles in a circle.

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<v SPEAKER_02>And when it does that, the particles are constantly changing direction, it gives off X-rays.

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<v SPEAKER_02>And those X-rays are significantly brighter, and there's significantly more of them, if you will, than there would be if you generate in the lab.

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<v SPEAKER_02>So it allows you to do experiments that are you can't do otherwise.

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<v SPEAKER_02>The other kind of thing we do a lot of is we have a portable X-ray analyzer.

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<v SPEAKER_02>It looks like a price scanner, and it generates high energy x-rays, and the matter absorbs them, the different atoms absorb them, and then they re-emit X-rays at energies that are specific to the atoms themselves.

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<v SPEAKER_02>So we put in one energy of X-rays and then we get a whole bunch of different ones coming off.

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<v SPEAKER_02>If we measure and count those X-rays at different energies, we can tell what something's made of.

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<v SPEAKER_02>Kind of there on the spot.

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<v SPEAKER_02>Like because this is portable, it runs on a battery, we can take this into the field and do things there.

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<v SPEAKER_06>You're just like price scanning the earth.

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<v SPEAKER_02>Indeed.

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<v SPEAKER_06>Element scanning.

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<v SPEAKER_02>It's priceless though.

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<v SPEAKER_06>Nice.

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<v SPEAKER_06>So how did you actually get into studying something like soil?

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<v SPEAKER_02>When I was in college, I went to William Mary in in Virginia.

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<v SPEAKER_02>Um and there was a lake on campus.

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<v SPEAKER_02>And I used to go hiking around it, and I'd find fossils in the woods there, and I learned a canoe and kayak there.

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<v SPEAKER_02>It was just a a really great place to get outside and escape from classes and stuff.

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<v SPEAKER_02>And um one time this group went out there and when they came back, a bunch of them got sores on their legs from um contamination in the lake.

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<v SPEAKER_02>Uh and I really liked this lake.

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<v SPEAKER_02>I wanted to know more about it.

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<v SPEAKER_02>So I was a chemistry major and a geology major at the time.

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<v SPEAKER_02>I went out there and kind of put on some waiters and stomped out into this area and I took cores and I tried to figure out like from the depth of these cores what was going on over time.

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<v SPEAKER_02>I like measured the composition and I I looked at some of the chemistry of things and I I tried to reconstruct of what had happened.

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<v SPEAKER_02>And uh it wasn't well this successful because it was a college undergraduate project, but I learned a lot and it made me realize the importance of soil and sediment and things like that, but also it made me realize kind of what's held there.

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<v SPEAKER_02>Like that there's all this information that's potentially buried there, as well as all these potential events, potential hazards, things that could be lying underneath your feet.

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<v SPEAKER_06>Oh, that's cool.

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<v SPEAKER_06>So it's kind of like you're taking a time machine.

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<v SPEAKER_06>When you take a core, you get a slice of all these different time periods.

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<v SPEAKER_02>Yep.

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<v SPEAKER_02>It's uh it's a little bit of archaeology, if you will, as well as just uh just looking at natural processes too.

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<v SPEAKER_06>Super cool.

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<v SPEAKER_06>So why is soil different from water and air when it comes to pollution?

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<v SPEAKER_02>Yeah, there's a lot of differences actually.

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<v SPEAKER_02>So one of them is like air and water pollution are much more transient.

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<v SPEAKER_02>If there's pollution in a river, it's gotta have a source or it's gonna wash down river.

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<v SPEAKER_02>Same with air pollution, right?

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<v SPEAKER_02>If the wind changes, the air might clear.

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<v SPEAKER_02>Soils are much less mobile, so they have the ability to have contamination linger in them for a much longer period of time.

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<v SPEAKER_02>The other thing is that uh air pollution and water pollution are pretty straightforward in thinking about how you're exposed, right?

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<v SPEAKER_02>There's some sort of gas or something in the air and you breathe it in, you're exposed.

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<v SPEAKER_02>If you drink water, you'll be exposed to whatever's in it.

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<v SPEAKER_02>Soil, it's a little more indirect, right?

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<v SPEAKER_02>It it could be you do you eat it or you consume it, and maybe it's on leaves of vegetables, or maybe a a child plays in it and consumes some of it.

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<v SPEAKER_02>Or maybe you breathe in dust.

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<v SPEAKER_02>Or maybe you get exposed because it contaminates the water you're drinking.

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<v SPEAKER_02>Or maybe you get exposed because the food that was grown in that soil takes up some of it.

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<v SPEAKER_02>So in some ways, there's more chance for indirect exposure, but it's also a little harder to gauge and think about.

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<v SPEAKER_06>Yeah.

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<v SPEAKER_06>I think that's interesting.

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<v SPEAKER_06>I mean, I've heard of all these superfund sites where there have been incidents or things have been put into the ground and it's still there.

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<v SPEAKER_06>Like it happened, it hasn't been remediated.

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<v SPEAKER_02>So the super funds are the big ones, right?

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<v SPEAKER_02>So there are surprisingly many of them.

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<v SPEAKER_02>Uh I can't remember the exact statistic off the top of my head, but I think something like one in four Americans lives within three miles of a superfund site.

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<v SPEAKER_02>Um superfund sites are are designated based on hazard.

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<v SPEAKER_02>So like it's not just that there's a a threat because of contamination in them, but also that there's people nearby.

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<v SPEAKER_02>So those are really big ones.

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<v SPEAKER_02>But there's also lots of little contamination out there, too.

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<v SPEAKER_02>People have lived in uh the world for a long time and they've done things sometimes not really understanding the consequences of them that have resulted in contamination.

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<v SPEAKER_02>If you think about it, anything that we have that's waste that we don't want anymore, it's either gonna end up in the ocean, but we don't like to dump things in the ocean anymore.

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<v SPEAKER_02>That's that's pretty much a no-no in in most people's mind.

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<v SPEAKER_02>Yeah.

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<v SPEAKER_02>Or it's it's either buried in the land or applied to the land.

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<v SPEAKER_06>I mean, I guess uh in the grand scheme of thing, right, that's like the better of the two options, and that at least like things can stay put for longer.

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<v SPEAKER_02>I think if you uh know where things are and you know what you're putting out, and you do things responsibly, like you know, if you have something that's gotta go in a landfill that's aligned and properly made, that's probably the best option.

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<v SPEAKER_02>But sometimes mistakes are made.

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<v SPEAKER_02>And of course, historically mistakes are made, and the problem is is that they stay with us for sometimes quite some time.

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<v SPEAKER_02>Back before we knew any better, there was a movement to try to incinerate trash in cities instead of taking it to a landfill.

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<v SPEAKER_02>You know, reduce the volume of it and then bury it or whatever.

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<v SPEAKER_02>So the problem with that is of course, beyond number one, you have all this ash now to deal with that's looks more sort of concentrated, but it's also affects air quality around it.

00:14:01.039 --> 00:14:06.480
<v SPEAKER_02>And that trend sort of ended maybe like the 1940s or so, somewhere in that era.

00:14:06.879 --> 00:14:10.879
<v SPEAKER_02>So you have these areas where there was an incinerator and what do you do with it?

00:14:11.039 --> 00:14:13.279
<v SPEAKER_02>Well, you just kind of cover up the ash, right?

00:14:13.360 --> 00:14:21.039
<v SPEAKER_02>And then over like decades, people kind of forget about it, and then you say, Hey, we got this nice green spot in the middle of town, let's make a park.

00:14:21.919 --> 00:14:31.919
<v SPEAKER_02>And then you slowly but surely realize that potentially your soils are contaminated because they're underlain by this material that was sort of domestic waste that was full of lead and other things.

00:14:32.159 --> 00:14:40.320
<v SPEAKER_02>So they found some issues of that in Durham, North Carolina, and in Greensboro, North Carolina, and it's not clear how spread it is, but it's also been found in other cities that did the same thing.

00:14:40.559 --> 00:14:49.759
<v SPEAKER_02>So there's lots of opportunities to to use that price scanner to go around and see if you can find these issues to try to reduce human exposure to potential hazards.

00:14:50.159 --> 00:14:55.679
<v SPEAKER_06>Gosh, that's like, you know, when people go scanning for metal, I like think of it that way, except like you're not finding stuff you want to find.

00:14:56.159 --> 00:14:57.440
<v SPEAKER_02>It's like a metal detector, right?

00:14:57.519 --> 00:14:59.120
<v SPEAKER_02>Except it's not the metals you want, right?

00:14:59.440 --> 00:15:00.000
<v SPEAKER_06>Oh, okay.

00:15:00.240 --> 00:15:00.399
<v SPEAKER_06>Yep.

00:15:01.120 --> 00:15:06.879
<v SPEAKER_06>I know that you've written about how soil chemists and environmental health sciences need to team up more.

00:15:07.360 --> 00:15:08.879
<v SPEAKER_06>Why is that important?

00:15:08.960 --> 00:15:11.440
<v SPEAKER_06>And and what do you think they can accomplish together?

00:15:12.000 --> 00:15:21.039
<v SPEAKER_02>If we're gonna solve problems out there, like really big complicated problems, we have to we have to form teams because not everybody can do everything.

00:15:21.279 --> 00:15:28.320
<v SPEAKER_02>So I have a narrow range of expertise, but I do have some expertise that is related to how chemicals move in soils.

00:15:28.639 --> 00:15:32.879
<v SPEAKER_02>And that might be important in certain situations where you're working with public health people.

00:15:33.039 --> 00:15:40.240
<v SPEAKER_02>Maybe they know more about how exposure happens and how to make interventions to try to stop exposure to those chemicals.

00:15:41.279 --> 00:15:56.960
<v SPEAKER_02>So I can run around with my with my little price scanner and tell you how much lead is in your soil, but then it really makes that much more impactful if someone is there to better interpret what that means for somebody's health and better explain to that person what it might mean for their health.

00:15:57.440 --> 00:16:02.080
<v SPEAKER_06>What keeps you up at night knowing what you know about what's in soil?

00:16:03.200 --> 00:16:09.919
<v SPEAKER_02>So when I was teaching my undergraduate class, I got a comment at the end of the year that said, This is a great class.

00:16:10.000 --> 00:16:10.720
<v SPEAKER_02>I really liked it.

00:16:10.879 --> 00:16:16.000
<v SPEAKER_02>Instructor's nice, but I will never eat, drink, or breathe anything ever again.

00:16:17.279 --> 00:16:17.919
<v SPEAKER_06>Oh my god.

00:16:19.440 --> 00:16:21.360
<v SPEAKER_02>I think that's that's one way to look at it.

00:16:21.759 --> 00:16:22.399
<v SPEAKER_06>Yeah.

00:16:22.639 --> 00:16:28.960
<v SPEAKER_06>Um what do you feel like the role of chemists is in protecting our soil?

00:16:29.519 --> 00:16:36.480
<v SPEAKER_02>I'm one of these people that believes that it's better to not make a mess ahead of time and have to go clean it up.

00:16:36.879 --> 00:16:44.000
<v SPEAKER_02>So I think it's important to think about these things and to try to develop pollution controls that allow us to not spread out things.

00:16:44.240 --> 00:16:51.600
<v SPEAKER_02>So I think a major goal is to think of ways to help mitigate pollution before it happens, as well as come up with new ways to clean it up.

00:16:58.159 --> 00:17:06.160
<v SPEAKER_04>So I know that Owen said it's of course better to not pollute in the first place, but what happens when something has been polluted?

00:17:06.319 --> 00:17:09.839
<v SPEAKER_04>Like, how do you clean up an area of polluted land?

00:17:10.160 --> 00:17:10.400
<v SPEAKER_06>Right.

00:17:10.480 --> 00:17:14.799
<v SPEAKER_06>Like what goes into remediating a site if it can be remediated?

00:17:15.119 --> 00:17:15.359
<v SPEAKER_06>Yeah.

00:17:15.680 --> 00:17:17.519
<v SPEAKER_06>I had a similar question.

00:17:17.599 --> 00:17:28.240
<v SPEAKER_06>Uh, so I talked with William Burgos, a professor of civil and environmental engineering at Penn State University, who focuses on remediation of polluted soils.

00:17:28.480 --> 00:17:36.400
<v SPEAKER_06>Specifically, he studies how microbes can be enlisted to help break down toxic waste, something known as bioremediation.

00:17:38.960 --> 00:17:45.359
<v SPEAKER_06>Penn State is located at the northern end of Appalachia, or Appalachia, however you like to pronounce it.

00:17:45.599 --> 00:17:48.720
<v SPEAKER_06>And that's a region that stretches across 13 U.S.

00:17:48.880 --> 00:17:54.000
<v SPEAKER_06>states from as far south as Mississippi and Alabama through parts of southern New York.

00:17:54.160 --> 00:18:02.480
<v SPEAKER_06>Apart from being a beautiful part of the country, Appalachia used to be a massive tropical swamp hundreds of millions of years ago.

00:18:02.720 --> 00:18:04.240
<v SPEAKER_06>Oh, that's that's crazy.

00:18:04.319 --> 00:18:05.279
<v SPEAKER_04>And so cool.

00:18:05.440 --> 00:18:08.240
<v SPEAKER_04>I love thinking about our landscape that long ago.

00:18:08.559 --> 00:18:09.920
<v SPEAKER_06>Yeah, and how different it was.

00:18:10.160 --> 00:18:10.480
<v SPEAKER_06>Yeah.

00:18:10.720 --> 00:18:22.319
<v SPEAKER_06>And that like wet, low oxygen environment with lots of plant matter led to kind of these perfect conditions to produce lots of coal, you know, for like millions of years.

00:18:24.319 --> 00:18:35.359
<v SPEAKER_01>Leave your big cities with their urban problems, drive along the highways, then off of them into God's country, up into the rolling Appalachian Mountains.

00:18:36.000 --> 00:18:37.359
<v SPEAKER_00>Coal is power.

00:18:37.680 --> 00:18:40.319
<v SPEAKER_00>And under the ground, we've got lots of it.

00:18:40.480 --> 00:18:44.559
<v SPEAKER_00>The coal lies under the surface in seams that run for miles.

00:18:44.640 --> 00:18:48.880
<v SPEAKER_00>And to get it out, miles of the country have to be gouged open.

00:18:50.880 --> 00:18:57.519
<v SPEAKER_06>With coal mining comes pollution from the ground that's dug up, uh, which is filled with heavy metals.

00:18:59.920 --> 00:19:07.440
<v SPEAKER_06>Appalachia has been known for mining since the 1700s, and at its peak, there were thousands of mines.

00:19:07.759 --> 00:19:15.119
<v SPEAKER_06>Today, though, only hundreds of mines are still in operation, and that means that many of them have become inactive.

00:19:15.599 --> 00:19:25.759
<v SPEAKER_06>So I started off my conversation with William by asking about these abandoned mines in his home state, how they affect the land, and ways to clean them up.

00:19:26.000 --> 00:19:27.440
<v SPEAKER_06>Here's our interview.

00:19:29.359 --> 00:19:39.039
<v SPEAKER_03>In 1917, I believe Pennsylvania generated the single largest amount of coal ever annually.

00:19:39.359 --> 00:19:44.720
<v SPEAKER_03>There was something like 217 million tons of coal generated by the state.

00:19:44.880 --> 00:19:51.759
<v SPEAKER_03>It arguably won World War I with respect to what all of that coal was used for.

00:19:51.920 --> 00:19:52.240
<v SPEAKER_05>Wow.

00:19:52.480 --> 00:19:57.839
<v SPEAKER_03>And you don't have to go far to encounter areas that have been impacted by coal mining.

00:19:58.079 --> 00:20:16.000
<v SPEAKER_03>And those impacts are fairly obvious in some cases where you just see massive remnants of unreclaimed land, poorly or unvegetated soils that are just sort of like spoil and refuse piled up from preparation of the coal.

00:20:16.240 --> 00:20:31.200
<v SPEAKER_03>And then, of course, on the waterways, where you see the acid mine drainage that comes out of these coal mines goes through a series of reactions that leads to the orange staining that you see on the stream bottoms.

00:20:31.359 --> 00:20:42.559
<v SPEAKER_03>There's a lot of iron sulfides that got oxidized in the mine or in the refuse piles that leads to soluble iron in the water running into the streams, causing all sorts of problems.

00:20:42.720 --> 00:20:47.279
<v SPEAKER_03>So the mining engineers are very talented and sophisticated people.

00:20:47.440 --> 00:20:51.440
<v SPEAKER_03>The legacy they left, unfortunately, is quite substantial.

00:20:52.000 --> 00:20:58.480
<v SPEAKER_03>So the net effect of those land disturbances all leads to the water contamination issue.

00:20:58.720 --> 00:21:04.079
<v SPEAKER_03>The obvious like discoloration, but uh there's also just habitat destruction and other things.

00:21:04.559 --> 00:21:11.039
<v SPEAKER_06>And so what is the work that you are doing to help remediate that situation?

00:21:11.839 --> 00:21:16.880
<v SPEAKER_03>In the case of Appalachian mine drainage, you want to oxidize the metals.

00:21:17.119 --> 00:21:34.559
<v SPEAKER_03>And so we've been looking at all of these natural processes, natural microbes that can oxidize iron and manganese out of the mine drainage and basically precipitate these oxides that can be collected in ponds or can be shoveled out.

00:21:34.880 --> 00:21:39.519
<v SPEAKER_03>So if we were to back way out, we can step back and talk about soils.

00:21:39.839 --> 00:21:50.319
<v SPEAKER_03>Because soils themselves are a key indicator of whether you're going to be successful in remediating them or not.

00:21:50.720 --> 00:21:50.960
<v SPEAKER_06>Okay.

00:21:51.279 --> 00:21:57.359
<v SPEAKER_03>And so soils can be classified by where they are vertically in the soil column.

00:21:58.319 --> 00:21:59.599
<v SPEAKER_03>They can also be classified.

00:22:00.319 --> 00:22:02.640
<v SPEAKER_03>Based on textural differences.

00:22:02.960 --> 00:22:19.599
<v SPEAKER_03>And so you dig up a pit of soil, you dry it out, you shake it through a series of different size graded sieves, and then you weigh the mass of soil that ends up in each sieve fraction.

00:22:20.079 --> 00:22:23.200
<v SPEAKER_03>And from that, you can define a soil type.

00:22:23.359 --> 00:22:26.799
<v SPEAKER_03>So if there's a lot of super fine stuff, then it's mainly clays.

00:22:27.039 --> 00:22:29.839
<v SPEAKER_03>If there's a lot of big, chunky stuff, it's more gravelly.

00:22:29.920 --> 00:22:33.759
<v SPEAKER_03>And there's all these different textures of soils.

00:22:34.079 --> 00:22:40.319
<v SPEAKER_03>There's also different letters that are assigned to that vertical soil horizon.

00:22:40.640 --> 00:22:42.160
<v SPEAKER_03>O A B C.

00:22:42.319 --> 00:22:43.519
<v SPEAKER_03>Have you have you heard of any of these?

00:22:43.759 --> 00:22:44.000
<v SPEAKER_03>I'm not.

00:22:44.160 --> 00:22:46.319
<v SPEAKER_06>I sound like blood types, but okay.

00:22:46.480 --> 00:22:49.359
<v SPEAKER_03>So the O, I believe, is for organic.

00:22:49.599 --> 00:22:50.640
<v SPEAKER_06>Is that at the very top?

00:22:50.880 --> 00:22:51.920
<v SPEAKER_03>It's at the very top.

00:22:52.079 --> 00:22:56.000
<v SPEAKER_03>And then the A is rather rich.

00:22:56.319 --> 00:23:00.640
<v SPEAKER_03>That's the brown kind of soil that you would like to see in your garden.

00:23:01.039 --> 00:23:08.960
<v SPEAKER_03>The B might be near the bottom of the garden where there's so much less organic matter that you can actually see the color change.

00:23:09.039 --> 00:23:11.920
<v SPEAKER_03>It's no longer primarily a brown color.

00:23:12.079 --> 00:23:14.880
<v SPEAKER_03>It's whatever your mineral soil is beneath it.

00:23:15.200 --> 00:23:27.039
<v SPEAKER_03>And then the sea horizon, which is where most of these deep groundwater contaminants end up going, is the sort of more mineral bedrock at the bottom of the well.

00:23:27.440 --> 00:23:39.200
<v SPEAKER_03>An A soil, you know, a nice organic rich soil that texturally matches like a large pore kind of structure.

00:23:39.359 --> 00:23:47.599
<v SPEAKER_03>That stuff's so much easier to remediate than a clay that is all these fine materials.

00:23:47.920 --> 00:23:53.119
<v SPEAKER_03>It's really difficult and slow for water and air to move through.

00:23:53.839 --> 00:24:06.720
<v SPEAKER_03>And so a a combination of this texture and location in the profile are as important as anything with respect to the success that you might have.

00:24:07.279 --> 00:24:07.759
<v SPEAKER_06>Yeah.

00:24:08.079 --> 00:24:17.759
<v SPEAKER_06>So then historically, like how have we gone about remediation of soil when we know it's contaminated with something?

00:24:18.079 --> 00:24:18.400
<v SPEAKER_03>Yeah.

00:24:18.640 --> 00:24:22.240
<v SPEAKER_03>Well, the the classic one is excavation and disposal.

00:24:22.960 --> 00:24:23.279
<v SPEAKER_03>Right?

00:24:23.440 --> 00:24:35.200
<v SPEAKER_03>You dig it up and you take it somewhere that ideally is a a better engineered setting where the chance of migration of those plutons has been minimized.

00:24:35.440 --> 00:24:35.680
<v SPEAKER_06>Okay.

00:24:35.920 --> 00:24:43.519
<v SPEAKER_03>So the classic, or let's say the first, you know, who knows how could be Romans even had this issue, right?

00:24:43.599 --> 00:24:44.079
<v SPEAKER_03>Like maybe.

00:24:44.400 --> 00:24:50.720
<v SPEAKER_03>You know, like you have a painting operation and the painter has been throwing all his waste paints out the back.

00:24:51.119 --> 00:24:52.720
<v SPEAKER_06>Michelangelo, stop doing that.

00:24:53.039 --> 00:24:56.160
<v SPEAKER_03>And you realize, like, hey, nothing's growing here anymore.

00:24:56.319 --> 00:25:02.400
<v SPEAKER_03>And so you excavate to what you believe is the extent of the contamination.

00:25:02.559 --> 00:25:03.839
<v SPEAKER_03>It's like a landfill, right?

00:25:03.920 --> 00:25:04.240
<v SPEAKER_03>Uh-huh.

00:25:04.559 --> 00:25:14.480
<v SPEAKER_03>In many cases, you're hoping for like a dry tomb kind of setting because you're also limiting the potential migration of any water contacting that and moving it off site.

00:25:14.559 --> 00:25:17.759
<v SPEAKER_03>So you have a membrane impermeable to water.

00:25:18.000 --> 00:25:18.480
<v SPEAKER_03>To water.

00:25:18.640 --> 00:25:18.799
<v SPEAKER_03>Okay.

00:25:18.960 --> 00:25:21.279
<v SPEAKER_03>And then you start bringing clay in.

00:25:21.519 --> 00:25:32.000
<v SPEAKER_03>You then compact to make a very resistant hydraulic layer so that any water that might move through that is going to go very, very slow.

00:25:32.480 --> 00:25:35.680
<v SPEAKER_03>And then on top of that, you start bringing in your material.

00:25:36.319 --> 00:25:39.599
<v SPEAKER_03>And then you do it on the sides and you do it on the top.

00:25:40.000 --> 00:25:42.799
<v SPEAKER_03>And you dry tomb it all all around.

00:25:43.119 --> 00:25:51.839
<v SPEAKER_03>And then you bring in topsoil and you put grass up there and some no trespassing signs so that nobody breaks that tomb cap.

00:25:52.079 --> 00:25:52.480
<v SPEAKER_06>I see.

00:25:52.720 --> 00:25:59.599
<v SPEAKER_03>And then the stuff that's in there should have very limited interaction with its environment.

00:26:00.079 --> 00:26:00.240
<v SPEAKER_06>Okay.

00:26:00.400 --> 00:26:09.359
<v SPEAKER_06>So you can take the waste that's in an area, you shovel it up, put it in a dry tomb, put a fence around it, and say, all done.

00:26:09.680 --> 00:26:15.039
<v SPEAKER_06>Are there more sophisticated methods now that we use for remediation?

00:26:15.440 --> 00:26:16.160
<v SPEAKER_03>Uh yes.

00:26:16.559 --> 00:26:17.680
<v SPEAKER_06>Okay, that's good.

00:26:18.319 --> 00:26:24.640
<v SPEAKER_03>The next most common one is when applicable, a bioremediation option.

00:26:25.119 --> 00:26:41.680
<v SPEAKER_03>And basically what you do is instead of digging those materials up and just hauling them to the landfill, you basically garden it to promote indigenous microbes that are there to oxidize organic contaminants.

00:26:50.160 --> 00:26:50.480
<v SPEAKER_03>Right.

00:26:50.720 --> 00:27:09.359
<v SPEAKER_03>Except on a grand scale, because who knows how much contaminated soil came out from that refinery or that pipeline rupture or something where you're taking all of these contaminated soils and you're sort of laying them out, but instead of burying them away forever, you're hoping to rehabilitate them basically.

00:27:09.519 --> 00:27:17.440
<v SPEAKER_03>And then you just run it to a point until that contaminant concentration drops below the regulatory threshold.

00:27:17.519 --> 00:27:21.279
<v SPEAKER_03>And then it's like, okay, hey, we can use it as clean fills somewhere.

00:27:21.599 --> 00:27:21.920
<v SPEAKER_06>Wow.

00:27:22.000 --> 00:27:23.039
<v SPEAKER_06>Thanks, bacteria.

00:27:23.279 --> 00:27:23.680
<v SPEAKER_03>Right, right.

00:27:23.759 --> 00:27:29.359
<v SPEAKER_03>So you have bioremediation, aerobic oxidative destruction of it.

00:27:29.599 --> 00:27:47.279
<v SPEAKER_03>Now, because of the predominance of chlorinated solvents, you know, vinyl chloride and TCE, trichloroethylene, and a bunch of other common industrial solvents that other technologies have developed to deal with these.

00:27:47.680 --> 00:28:12.880
<v SPEAKER_03>And these compounds, these, you know, polyhalogenated compounds, are only going to be bioremediated under anaerobic conditions, where you promote a process called reductive dehalogenation, which is taking chlorines or fluorines off of those carbon backbones that can be converted to CO2 or methane or something like that.

00:28:13.680 --> 00:28:20.720
<v SPEAKER_06>So you're saying that I mean this once again would be done by microbes, but microbes that need to not have any oxygen.

00:28:20.960 --> 00:28:21.119
<v SPEAKER_05>Right.

00:28:21.359 --> 00:28:26.880
<v SPEAKER_06>And luckily those compounds, because they're so dense, they end up in the area where there's really not that much oxygen.

00:28:26.960 --> 00:28:30.640
<v SPEAKER_06>And so the microbes that are there are also the ones that can do the work.

00:28:31.279 --> 00:28:31.519
<v SPEAKER_03>Right.

00:28:31.839 --> 00:28:35.839
<v SPEAKER_03>Now the the the challenge there is that the bioenergetics is low.

00:28:36.079 --> 00:28:36.240
<v SPEAKER_03>Okay.

00:28:36.480 --> 00:28:49.200
<v SPEAKER_03>And so this process takes so long that there has been this pivot, and I shouldn't diminish it, but this idea of monitored natural attenuation.

00:28:49.599 --> 00:28:51.680
<v SPEAKER_06>Monitored natural attenuation.

00:28:52.160 --> 00:28:52.480
<v SPEAKER_03>Okay.

00:28:52.720 --> 00:28:58.400
<v SPEAKER_03>Which is basically you're just leaving all the mess underground and you monitor.

00:28:58.720 --> 00:29:00.960
<v SPEAKER_06>And you just don't use it until it's okay.

00:29:01.279 --> 00:29:01.519
<v SPEAKER_03>Yeah.

00:29:01.680 --> 00:29:05.200
<v SPEAKER_03>And you just hope that over time, you know, 20 years later or something like that.

00:29:05.519 --> 00:29:09.359
<v SPEAKER_06>That's the do nothing approach to uh bio to remediation.

00:29:09.839 --> 00:29:11.920
<v SPEAKER_03>Now it has the an its own acronym.

00:29:12.240 --> 00:29:12.799
<v SPEAKER_06>Nice.

00:29:13.119 --> 00:29:13.599
<v SPEAKER_03>Yes.

00:29:13.839 --> 00:29:14.160
<v SPEAKER_03>Yes.

00:29:14.240 --> 00:29:15.759
<v SPEAKER_03>So we can excavate it.

00:29:15.920 --> 00:29:20.000
<v SPEAKER_03>We can bioremediate the oxidizable organics.

00:29:20.160 --> 00:29:26.400
<v SPEAKER_03>We can anaerobically degrade the halogenated ones, but it's very complicated, it takes a long time.

00:29:26.559 --> 00:29:28.240
<v SPEAKER_03>And then of course, you can burn it.

00:29:28.720 --> 00:29:29.920
<v SPEAKER_03>Thermal oxidation.

00:29:30.079 --> 00:29:32.079
<v SPEAKER_03>Yeah, like burn everything.

00:29:32.319 --> 00:29:36.720
<v SPEAKER_03>Now, the problem with that is the energy involved in it.

00:29:36.799 --> 00:29:36.960
<v SPEAKER_03>Yeah.

00:29:37.200 --> 00:29:41.680
<v SPEAKER_03>You still have a combustion off-gas treatment train that you have to deal with.

00:29:41.920 --> 00:29:42.160
<v SPEAKER_06>Right.

00:29:42.319 --> 00:29:42.559
<v SPEAKER_03>Yeah.

00:29:42.720 --> 00:29:46.319
<v SPEAKER_03>And then you're turning a soil into mineral.

00:29:47.599 --> 00:29:55.519
<v SPEAKER_03>You're burning, you're burning every bit of leaf litter, any fertile component out of that soil.

00:29:56.240 --> 00:29:59.119
<v SPEAKER_06>And you're you're adding to greenhouse gases.

00:29:59.519 --> 00:30:01.119
<v SPEAKER_03>Well, for sure there's CO2.

00:30:01.200 --> 00:30:04.400
<v SPEAKER_03>And you're burning the fuel to jack it up there too, right?

00:30:04.880 --> 00:30:05.119
<v SPEAKER_06>Right.

00:30:05.599 --> 00:30:08.720
<v SPEAKER_03>But the cheapest option is always going to be the one selected.

00:30:08.960 --> 00:30:20.079
<v SPEAKER_03>And if truck and tomb is the cheapest, then the technology doesn't advance to using other things that say people in the research community are looking at.

00:30:21.200 --> 00:30:24.000
<v SPEAKER_06>So what is Cueva de la Mora pit lake?

00:30:24.079 --> 00:30:25.279
<v SPEAKER_06>I know you've done work there.

00:30:25.440 --> 00:30:28.480
<v SPEAKER_06>What does it look like and why did you want to study it?

00:30:28.880 --> 00:30:36.400
<v SPEAKER_03>So Cueva de la Mora is an acidic pit lake in the Iberian pyrite belt in southwestern Spain.

00:30:36.559 --> 00:30:43.359
<v SPEAKER_03>So the Iberian pyrite belt, the IPB, spans Portugal and Spain.

00:30:43.599 --> 00:30:43.920
<v SPEAKER_05>Okay.

00:30:44.160 --> 00:30:47.359
<v SPEAKER_03>It's the largest sulfide body in the world.

00:30:47.519 --> 00:30:52.400
<v SPEAKER_03>You know, the amount of metals that have been extracted out of there are tremendous.

00:30:52.960 --> 00:30:59.440
<v SPEAKER_03>It's been mined since like the Phoenicians and the Romans mined it actively.

00:30:59.920 --> 00:31:07.920
<v SPEAKER_03>So much of the Roman weaponry and sculpture probably came out of this part of the world.

00:31:08.160 --> 00:31:08.559
<v SPEAKER_03>Wow.

00:31:08.720 --> 00:31:12.640
<v SPEAKER_03>And Cueva de la Mora is a so-called open cast mine.

00:31:13.039 --> 00:31:20.799
<v SPEAKER_03>So a famous one in the United States is the Berkeley Pit, which is a massive copper mine up in Montana.

00:31:20.960 --> 00:31:24.000
<v SPEAKER_03>It's also the largest super fund site in the country.

00:31:24.240 --> 00:31:24.559
<v SPEAKER_05>Really?

00:31:24.799 --> 00:31:33.440
<v SPEAKER_03>And so these are massive corkscrew-like pits where you start working your way down to get more and more of it.

00:31:33.599 --> 00:31:33.920
<v SPEAKER_06>Okay.

00:31:34.160 --> 00:31:37.680
<v SPEAKER_03>So these things become these deep conical pits.

00:31:37.839 --> 00:31:38.160
<v SPEAKER_06>Ah.

00:31:38.400 --> 00:31:41.759
<v SPEAKER_03>But then eventually one day they stop and they walk away from it.

00:31:42.000 --> 00:31:46.160
<v SPEAKER_03>And they start to fill with water and they become an acidic pit lake.

00:31:46.400 --> 00:31:46.720
<v SPEAKER_06>Ah.

00:31:47.200 --> 00:31:50.000
<v SPEAKER_03>And so that's what Cueva de la Mora is.

00:31:50.079 --> 00:32:03.039
<v SPEAKER_03>And the IPB is such a big and metal-rich area that it has like 20 or more of these lakes that rival the Berkeley Pit, which is the largest one in our country, right?

00:32:03.119 --> 00:32:04.880
<v SPEAKER_03>So there's many of them.

00:32:05.200 --> 00:32:11.200
<v SPEAKER_03>Cueva de la Mora, though, has been studied intensively by the Spanish Geological Survey.

00:32:11.440 --> 00:32:21.680
<v SPEAKER_03>So they've equipped the lake with like permanent buoys so you can go out there and clip your boat to it and do your field work, do your sampling always in the same location.

00:32:22.000 --> 00:32:26.480
<v SPEAKER_03>And the lakes are really fascinating because the chemistry is so extreme.

00:32:27.119 --> 00:32:30.799
<v SPEAKER_03>At least one of these pit lakes has a pH of 0.7.

00:32:32.079 --> 00:32:33.039
<v SPEAKER_06>Oh my gosh.

00:32:33.279 --> 00:32:33.599
<v SPEAKER_03>Right?

00:32:33.759 --> 00:32:35.599
<v SPEAKER_06>Like that's like dangerous.

00:32:35.759 --> 00:32:38.960
<v SPEAKER_03>Like you'd you fall in, you would burn yourself for sure.

00:32:39.200 --> 00:32:39.920
<v SPEAKER_06>Oh my gosh.

00:32:40.160 --> 00:32:41.200
<v SPEAKER_03>And they're very deep.

00:32:41.279 --> 00:32:49.200
<v SPEAKER_03>And the metal concentration is so high that they're so dense that they remain permanently stratified.

00:32:49.359 --> 00:32:58.720
<v SPEAKER_03>And so now you have this extreme geochemistry and this extreme isolation from the surface in the deep layer of these lakes.

00:32:58.799 --> 00:33:11.839
<v SPEAKER_03>And so that's what we've been really interested in, because there are these very exotic and rare extremophiles, these microbes that are somehow living in these really harsh conditions.

00:33:12.480 --> 00:33:23.680
<v SPEAKER_03>We are interested in whether these microbes could be exploited in some way for remediation purposes, kind of like what we've done in the Appalachian system.

00:33:23.839 --> 00:33:28.880
<v SPEAKER_03>Except in the Appalachian system, we're looking at aerobic surface waters.

00:33:29.039 --> 00:33:33.599
<v SPEAKER_03>And in the Spanish system, we're looking at anaerobic deep waters.

00:33:33.839 --> 00:33:34.079
<v SPEAKER_05>Okay.

00:33:34.240 --> 00:33:45.680
<v SPEAKER_03>But in either case, the the goal is to promote biological reactions that lead to the precipitation of the metals into some very sparingly soluble form.

00:33:46.079 --> 00:33:53.759
<v SPEAKER_06>And so uh have you found any like really cool microbes that you weren't expecting to find, some crazy extremophiles?

00:33:54.240 --> 00:33:59.759
<v SPEAKER_03>The challenge with the extremophile kind of research is you have to figure out what the thing is.

00:34:00.880 --> 00:34:03.519
<v SPEAKER_03>Because right, like nobody's found it before.

00:34:03.599 --> 00:34:08.400
<v SPEAKER_03>And uh, we have been able to identify a number of unique organisms that are down there.

00:34:08.719 --> 00:34:09.519
<v SPEAKER_06>That's so cool.

00:34:09.920 --> 00:34:10.639
<v SPEAKER_06>That's exciting.

00:34:10.960 --> 00:34:12.960
<v SPEAKER_03>Yeah, Cueva de la More is very cool.

00:34:13.280 --> 00:34:16.320
<v SPEAKER_06>What did you think when you first saw the lake?

00:34:16.719 --> 00:34:23.039
<v SPEAKER_03>You know, for for certain geochemists, it's like a place you must go.

00:34:23.119 --> 00:34:24.960
<v SPEAKER_03>You know, it's like Yellowstone.

00:34:25.360 --> 00:34:27.840
<v SPEAKER_03>Like you you have to go to this place.

00:34:28.000 --> 00:34:28.400
<v SPEAKER_06>Yeah.

00:34:28.639 --> 00:34:34.079
<v SPEAKER_03>And I'm looking around and I'm like, this is a tremendously impacted landscape.

00:34:34.239 --> 00:34:38.159
<v SPEAKER_03>Because right next to Cueva de la Mora is the refuse pile.

00:34:38.320 --> 00:34:46.079
<v SPEAKER_03>And so my initial impression of that area, as excited as I was, was just ghastly human impact.

00:34:47.119 --> 00:34:53.679
<v SPEAKER_06>Speaking of ghastly human impact, uh, what what do you think is like most concerning about the state of our soil?

00:34:53.760 --> 00:34:55.679
<v SPEAKER_06>Like what keeps you up at night?

00:34:56.960 --> 00:35:02.480
<v SPEAKER_03>Well, our soils feed us and filter all our water, right?

00:35:02.559 --> 00:35:09.599
<v SPEAKER_03>Like and if you say that enough times, then you start to appreciate that stuff a little bit more.

00:35:10.559 --> 00:35:23.519
<v SPEAKER_03>So any activity that disrupts the function of the soils with respect to allowing for crops to grow or for clean water to come through is of concern, you know?

00:35:23.760 --> 00:35:28.639
<v SPEAKER_03>And so if you have to have a landfill, we make a lot of trash.

00:35:28.880 --> 00:35:30.400
<v SPEAKER_03>Our trash is going somewhere.

00:35:30.480 --> 00:35:30.719
<v SPEAKER_03>Right.

00:35:30.880 --> 00:35:37.199
<v SPEAKER_03>You got to make sure it's located in areas that minimize environmental risks to the surroundings.

00:35:37.440 --> 00:35:44.159
<v SPEAKER_03>A good friend of mine liked to say that soils are the living skin of the world.

00:35:45.440 --> 00:35:50.159
<v SPEAKER_03>And they're so more complex than we really appreciate.

00:35:50.320 --> 00:35:57.440
<v SPEAKER_03>You know, textures, minerals, microbes, climate variations, all sorts of stuff.

00:35:57.599 --> 00:36:01.840
<v SPEAKER_03>You know, again, the soil feeds us and filters our water.

00:36:02.000 --> 00:36:03.280
<v SPEAKER_03>That's all I gotta say.

00:36:08.320 --> 00:36:13.039
<v SPEAKER_03>And so we just need to respect our soils and treat them right.

00:36:13.280 --> 00:36:15.119
<v SPEAKER_06>Treat them right, they'll treat us right.

00:36:15.440 --> 00:36:16.719
<v SPEAKER_03>That's the mic drop.

00:36:16.880 --> 00:36:18.880
<v SPEAKER_06>That's nice, I'll take it.

00:36:38.000 --> 00:36:41.840
<v SPEAKER_06>Yes, just want to say no mics were harmed in this recording.

00:36:42.159 --> 00:36:47.920
<v SPEAKER_06>But I did learn a lot more about soil than I ever thought that I would, and it turned out to be fascinating.

00:36:48.239 --> 00:36:54.559
<v SPEAKER_06>Also, William mentioned this other polluted water source in the Iberian pyrite belt.

00:36:54.800 --> 00:36:57.039
<v SPEAKER_06>It's called Rio Tinto.

00:36:57.199 --> 00:37:00.320
<v SPEAKER_06>And Sam, I'm gonna need you to look this up.

00:37:00.639 --> 00:37:01.039
<v SPEAKER_06>All right.

00:37:01.280 --> 00:37:03.360
<v SPEAKER_06>So, like the first picture that pops up.

00:37:03.679 --> 00:37:04.000
<v SPEAKER_06>Okay.

00:37:06.559 --> 00:37:09.840
<v SPEAKER_04>Wow, that is very, very red.

00:37:10.639 --> 00:37:11.920
<v SPEAKER_04>Like it looks fake.

00:37:12.159 --> 00:37:13.760
<v SPEAKER_06>Yeah, it does look fake.

00:37:13.920 --> 00:37:21.679
<v SPEAKER_06>And that's actually from lots of dissolved metal, especially iron, in this extremely acidic environment.

00:37:21.840 --> 00:37:25.840
<v SPEAKER_06>I think the pH is like around, I don't know, somewhere around 2, 2.5.

00:37:26.079 --> 00:37:27.360
<v SPEAKER_06>Crazy acidic.

00:37:27.599 --> 00:37:41.280
<v SPEAKER_06>And while it is really fascinating to scientists to study the extremophiles that can somehow make it in these conditions, obviously the absence of other organisms that once thrived in the area is an issue.

00:37:41.519 --> 00:37:41.920
<v SPEAKER_04>Right.

00:37:42.079 --> 00:37:56.639
<v SPEAKER_04>I mean, this whole mini-series so far has brought home the different ways that we can really affect our environment with chemistry, but also all the ways that chemistry can help us measure those changes and lead to new solutions to the problems that we've caused.

00:37:56.880 --> 00:37:57.679
<v SPEAKER_04>True.

00:38:01.280 --> 00:38:07.119
<v SPEAKER_06>Sam, I think it's time to zoom out and take a look at our impact on Earth as a whole.

00:38:07.280 --> 00:38:15.199
<v SPEAKER_06>Not just pollution per se, but all the ways that we perturb our big blue planet in ways that will be difficult to recover from.

00:38:15.440 --> 00:38:22.480
<v SPEAKER_06>And also how scientists are monitoring these global changes and deciding when something's a problem.

00:38:22.719 --> 00:38:24.239
<v SPEAKER_06>Not an easy task.

00:38:24.480 --> 00:38:28.079
<v SPEAKER_06>And that's on the final episode of this mini-series.

00:38:28.320 --> 00:38:30.480
<v SPEAKER_06>So join us next week.

00:38:36.159 --> 00:38:41.119
<v SPEAKER_06>This was Chain Reaction, a podcast by the American Chemical Society.

00:38:41.360 --> 00:38:43.760
<v SPEAKER_06>Our executive producer is Sam Jones.

00:38:43.920 --> 00:38:46.000
<v SPEAKER_06>The producer is me, Margot Wall.

00:38:46.320 --> 00:38:48.320
<v SPEAKER_06>Research was done by Beck Roll Don.

00:38:48.800 --> 00:38:50.639
<v SPEAKER_06>Fact-checking by Michelle Boucher.

00:38:51.039 --> 00:38:54.159
<v SPEAKER_06>Production help from Michael David and Matt Radcliffe.

00:38:54.400 --> 00:38:55.920
<v SPEAKER_06>Our theme song is by D.

00:38:56.079 --> 00:38:57.039
<v SPEAKER_06>Peterschmidt.

00:38:57.280 --> 00:39:03.199
<v SPEAKER_06>The use of archival sound for the 1972 EPA film 5,000 Dumps was granted by A.

00:39:03.360 --> 00:39:03.519
<v SPEAKER_06>B.

00:39:03.679 --> 00:39:04.079
<v SPEAKER_06>Geeks.

00:39:04.800 --> 00:39:08.239
<v SPEAKER_06>Do you have a comment or a question about the podcast?

00:39:08.480 --> 00:39:12.639
<v SPEAKER_06>Email us at chainreaction atacs.org.

00:39:12.800 --> 00:39:14.719
<v SPEAKER_06>We would love to hear from you.