Instant Genius - Poisons, with Dr Raychelle Burks

Episode Date: September 26, 2021

Chemist Dr Raychelle Burks tells us all about poisons, from how to tell what substance was used, to whether there are any poisons that are undetectable. Once you’ve mastered the basics with Instant Genius, dive deeper with Instant Genius Extra, where you’ll find longer, richer discussions about the most exciting ideas in the world of science and technology. Only available on Apple Podcasts. Produced by the team behind BBC Science Focus Magazine. Visit our website: sciencefocus.com Hosted on Acast. See acast.com/privacy for more information. Learn more about your ad choices. Visit podcastchoices.com/adchoices

You said this place was steps from the water. We just haven't found the steps yet. How much did we save? Enough. Enough to get lost. Or you could book a stay with Hilton. Welcome to your ocean front room. Just steps from the water.

The Hilton sale is on now. Book on Hilton.com or the Hilton app and save up to 20% to get the stay you expected. When you want savings, not surprises. It matters where you stay. Hilton, for the stay. It's peak pollination season, and my business is scaling fast. To keep the nectar flowing, I need a phone plan with top priority data speeds.

That's why I chose GoogleFi Wireless. My connections stay strong even when the hive is buzzing. Plus, unlimited plans started $35 a month. Now, that's a deal that doesn't stay. Explore Google Fi Wireless plans today. Plus taxes and government fees. GoogleFi Wireless is not subject to data traffic deprioritization during times of high network usage. No one goes to Hank's for his spreadsheets.

They go for a darn good pizza. Lately, though, the shop's been quiet. So Hank decides to bring back the $1 slice. He asks Copilot in Microsoft Excel to look at his sales and costs. Help him see if he can afford it. Co-pilot shows Hank where the money's going and which little extras make the dollar slice work. Now, Hank has a line out the door.

Hank makes the pizza. Co-Pilot handles the spreadsheets. Learn more at M365 copilot.com slash work. This podcast is sponsored by name, audio and focal. Streaming has made music more accessible than ever, but true listening is about more than ease. It's about quality. British audio experts name audio,

alongside French acoustic specialist focal, combine handcrafted tradition with cutting-edge innovation and high-end materials, delivering digital precision with analogue warmth. So you can experience exceptional sound at home. Music just as the artist intended. Visit name audio.com to learn more. Welcome to Instant Genius, a bite-sized masterclass in podcast form. I'm Sarah Rigley, online staff writer at BBC Science Focus magazine.

In this week's episode, I speak to Dr. Raichael Birx. She's an associate professor of chemistry at American University in Washington, D.C. And previously, she worked as a forensic scientist in a crime lab. She tells me all about poisons, from how to tell what substance was used in and attack to whether there really are any poisons that are completely undetectable. So first of all, just to begin, could you please tell us a bit about yourself? What do you do and how did you get there? So my name is Dr. Rachel Birx.

I am a chemist, specifically an analytical chemist. So I don't make chemicals, I find them. So I like to think of myself as a chemical detective. And I got there really from a life of crime. I've always been really interested in the legal system. I thought I was going to be a lawyer when I was little. And then I discovered forensic science around junior high, 12, 13, somewhere in that angle. And started my grandmother started giving me like Agatha Christie books and murder she wrote.

And so then I just was like really interested in how you could use science. to again live this life of crime. So it kind of really went in that area of being a detective on how we can discover different processes and how chemicals work and really solving a lot of puzzles. So you used to work in a crime lab, is that right? I did, yes, yes. When you would walk onto a crime scene, how would you go about figuring out whether or not someone had been poisoned? Well, you know, poisoning cases in that kind of context, they're kind of rare, right? In that most poisonings, the world over, are accidents because we do real wild stuff sometimes. And it's just a pure accident of just, you know, kids or you just thought it was something else or all of that. And so sometimes

you wouldn't know, right? And I personally did not ever run in to a kind of a scene where you would see that. But definitely the things that you would look for, if the person was deceased, if they were still living, there's lots of great questions you would ask and you would just consider, okay, you know, how are they feeling? Do they seem intoxicated? And we shouldn't always assume that that's a self-medicated, if I could use that phrase, state. But let's say that there, you know, let's go total midsummer murders. This is some scene is that you could look for, you know, signs of distress. And it's not always like, oh, this was a fighter struggle. It could be that when we're sick or distress, we show all kinds of signs of distress, right? There might be if there's

vomiting on the scene, because you have this physiochemical response where, you know, just you want to get it out, right? And we see that. And a lot of creatures do that, right? They're like, no, this has got to go. So you see something like that. Or even if there's maybe signs of, they, they've been taking something or there's a certain, you know, paler. There are certain poisons that are actually, there's going to be distinctive physical manifestations sometimes. So one that often people talk about, and I'm sure it's been on a lot of the classic crime shows, is, you know, if it's carbon monoxide, it's that, you know, sometimes that cherry red, right,

of the skin. But sometimes, you know, the most diabolical poisons can, can disguise. and every Agatha Christie fan knows this. It can seem like a long decline, some type of gastro, intestinal distress, right? So some of it, a lot of it would be asking the questions of, you know, how long have they been ill looking for those types of things. You know, there's a lot of the heavy metals, same type, you know, arsenic,

you know, the kind of classic ones you think of, have that gastrointestinal stress. But then other ones have such unique manifestations that the minute, that the minute you hear them, you're like, ah, and then you can go chemically check. And one would be thallium. You know, if you start seeing, of course, the gastro intestinal, which, you know, that doesn't narrow it down. There's a lot of them that cause that. But then it's tingling in the extremities, especially the lower extremities, feeling like the worst sleep, you know, when your legs are asleep, the worst ever. And hair falling out, thalium. Like that's, and then the minute,

the minute you have a good clue of the type of chemical you're looking for, then you can get that confirmatory validation by running the right test. And then you're like, go look and see if we've got Valium in blood and you might look at tissues depending on what kind of samples available. So you really are kind of, again, looking for the context clues. If the person can disclose things, physical appearance. And of course, from pathology standpoint, there can be some real signs when you start looking at tissues and organs and things like that. So when someone tried to poison someone else, you might think that they'd try and use something kind of innocuous. So something they'd find around the house or something they might expect to find in their system. So it could be a medication, it could be, you know, something like that.

So how would you define what a poison is? Is it just something that we try and use to hurt someone else? or does it have a specific definition? You know, it's a very broad definition. I think when we, you know, when the common person and our common conversation, when we use poison, we are meaning like pure, diabolical, you know, cyanide, arsenic, stricney, you know, that. But a poison really is anything you're exposed to that messes up your normal bodily functions. Alcohol, drinking alcohol, totally a poison.

Delicious for some of us. You know, and so it can, and that's a very, that's a very, broad category. And that's often why we have this true, but also cliche, when we say that dose makes the poison. And then, of course, though, when we think about the poisons, it's those things that you're like, there is no good reason for this to be there. Like, there's, it isn't like, oh, they just drank the wine. I mean, the red mine might be delicious, but it also could be a good disguise for stricting, which there's no good reason for that to be there. So, you know, it's really about that. way. But I think there's those dual uses, you know, when we kind of say in popular parlance and when

we just kind of mean, no, it is anything that could cause a disruption to your system, including if you drink far too much water. It can really upset your eye on balance. So it's a really broad category. Right. Okay. And what sort of tests would you do to say a dead body or even, I suppose, someone who's in hospital to figure out what they had been poisoned with? Oh, gosh. Okay. So of those, again, the contextual clues, because here's the challenge is that it's not so much that poisons are undetectable, you know, and they say, oh, it's non-detectable. Are we looking for it? Right? That's, you know, it sounds kind of silly to say, but we can only find what we're looking for. So, you know, you're, you know, when you run a tox panel or when someone goes, they're

not testing against everything in the known universe. They're going to go for like, okay, what are the most common things that we're seeing in our area that we know are kind of the big problem. So they might do those initial screens for those things. And a lot of the times, they also are informed by, you know, what is kind of in the drug usage scale, right? Because a lot of drugs, again, dose makes the poison. It could be that. But then again, it's informed by, okay, what are the tests, right? What are the symptoms? So if a person is able to communicate like with the thallium example, then you would be, you know, okay, do the heavy metal panel. And I think it's going to be this one, but let's do the

whole panel to be sure. And you could order very specific ones. And so based on kind of those manifestations that you would be looking at and that you've got to order the right one. So sometimes the examples of when, oh, it's, you know, hasn't been found, it's because we weren't looking for it. And sometimes, you know, some, including, you know, over the counter drug, the tricky things is because they're used up, they're metabolized by our body to kind of get them out as is possible. That interval of time is so short between the time you discover there might be a problem and the person has been exposed to it that the parent compound, the actual poison that we're looking for isn't around. But one of its little metabolites might be around. And some of those

metabolites, again, are as distinctive as the thing that you are really kind of suspicious of. And so that might actually be the thing that you're looking for. And probably maybe one that people have heard of would be like GHB, where again, depends on that time interval and when you're doing the test, but you might be able to find some of those metabolites. And if we can't, for some reason, test the individual or those screens are not useful, then is there some food problems? And or a drink product or something that they've been exposed to in the environment that you might also be able to test in that way. Right, I see.

So are there any poisons that are just totally undetectable? I as an analytical chemist would say a no. It's really a question of what samples do you have access to? And in analytical, you know, we like to think that we can find anything. You know, we're like that what is that Liam Neeson character? I have a particular set of skills. I will find you. Like this said with like, it's real bravado.

But when it comes down to it is, is it detectable? And it's not, we never say it's not there. We say it's not detected. And that sounds like a real like minutiae inside baseball thing. But it basically means every test that we do, it includes what's the lower limit of detection. What's the lowest amount we can compensate. confidently say is there. And that's different than a limit of quantitation, which is the lowest amount that we can reliably count over and over again and really get, you tell you how much is there,

not just what's there, but how much. And usually that what's called the LOD limit of detection is lower than the LOQ, limit of quantitation. But if you're even lower than that, because again, maybe lots of time is gone by in the metabod processes of even, a living person, but even if a deceased person, maybe, you know, the decay process and by the time that you're sampling remains, that could really be an issue, then if it's below that, what we would say is it's not detected, which in our technical doesn't mean it's not there. But we're always coming up with new analytical devices. You know, 100 years ago, 120 years ago, the lower limit of, say, arsenic in stomach contents, man, we can top that by orders of magnitude today. So we're always

kind of dropping it, right? And the thing is, are we looking for the right thing? So there has been some very high profile cases where, let's say the insulin murders, where there have been some real high profile cases in that, where it should already be there. So it's sometimes not a thing we're looking for. And if you found it, you'd be like, Okay, right? But it's about how much. It's about when you did the test. And did you actually look for insulin, you know, on how it manifests itself? So it's not that it's not a detectable because we can actually find it pretty well. We're very good at that. We have at home get. Like, you know, we're very good at kind of finding either whether it's working or not or locating it directly. But that doesn't mean that are we looking for it? That's the big question is, is are we looking for it? And that's where the sneaky part comes in is if you have, it's not so much that you've chosen some of these diabolical characters,

both truth and fiction, it's not so much that they've chosen like, this diabolical poiso ever. It's that they picked one that nobody was going to be looking for. They chose a collection of things where there was enough of a time interval or the person was already sick with something that looked very similar combined with a, you know, routine, there was something like super suspicious that came out of nowhere, like an insurance policy taken out two weeks before, or, you know, all of those kinds of tropes that we see,

then you just might get away with it because it's a combination of like nobody was looking. So not so much chemistry trickery than character trickery. So from a chemical point of view, are there any features of something that would make a point of poison particularly deadly? What makes a good poison? Ooh, my first question, and I've been asked this sometimes when I've consulted on shows and tea and stuff, is, well, what do you want it to do? And how do you want the person to suffer? Very diabolical, like, do you want them to die? How fast do you want them to die? Do you want to suffer, you know, and that, there's a range. There is this dizzying array of substances. I heard once

that, you know, nature is trying to kill us. Like, you know, doesn't care about us. But, you know, between, there's such a variety of poisons and attack. Like, it seems like every one of our systems that, you know, you can't pick even sometimes the best one because what is it that you want it to do? I mean, the go-toes, of course, I think people would be like, cyanide, right? Potentially, at a sufficient concentration, it can be very fast. But in the other hand, you might really hate somebody? And you're like, not only do I want them to die, I want them to suffer. And then that, I mean, that's a level of other stuff, right? But also it could be that you want to disguise it. So strychnine can be incredibly painful because contraction in the muscles,

works completely differently than cyanide, completely differently, the carbon dioxide. And sometimes those contractions are so violent, it pulls the muscle from the bone. Ooh, ouch. Right? So that's bad news, bears. There can be quite a long interval. But what it can also mimic is tetanus. So are you trying to kind of be a bit crafty?

Do you want? So there's a little bit, it sounds very weird, but you're like, what do you want it to do? And it's, man, that's creepy. And I know I sound creepy saying it. What's the fastest the poison can act? Oh, you know, it really, again, the dose and the delivery route. So some poisons, right, work better? Is that the right?

Are more lethal depending, you know, are they ingested, injected, inhaled, and really about concentration. And a lot of these, including drugs that we take for wellness and treatment, it's about an amount per unit of weight and how fast we want it to react, which is why if anyone's ever got in general anesthesia, don't lie about your weight. They're going to make you get out of scale because they want to balance it just right to do the anesthesia and the pain relief, right, and all of that kind of thing. And it's the same because of, you know, these are things that have a biochemical action.

It's the same. So a lot of times it's that. And it can also be underlying health conditions. Is there something else? Some of them, if they're adjusted, did you have a big meal that could maybe, you know, slow or if it's on an empty stomach could kind of speed it up. So there's a little bit, you know, of a give and take there. But sometimes, you know, again, if it's like bigger, you know, sometimes the general rule is

go big or go home. This case, it would be go big and they will not go home. That's kind of how they. that works. So in TV and things, you often see someone will be poisoned with something and it could be within seconds. They start feeling the effects. Is that realistic? My gut is a no. But that doesn't mean that it can't be incredibly fast. I mean sometimes, right, the minute that they ingest a poison, like the cup is still in their hand and they're like, boom, boom, right? It can be that fast. But however, you know, and especially if the

poison it is. And I say that because some of the ones that they've used that are plant alkaloids, something to know about alkaloids is their bitter. And so, you know, they name off the cocktail and they say, oh, it turned out to be, you know, strychnine or so. And you're like, and they didn't notice that because they've been sauced up for a while. They know what a martini tastes like and they should not have, you know, like, and that's how there's so many bitter receptors you would have, you know, known it unless, again, something's happened to you that you're not aware. And then, you know, what is it? You know, so sometimes it's weird stuff like that or sometimes it's, the speed is almost too fast. But is that, like sometimes the timing in these things, you're not sure how

much time has gone by. You know, if you're at a party, is it really the minute or is it supposedly been several minutes? And some of the concentrations, like with the cyanides, which is, you know, know, kind of the go-to in these scenarios. It can be quite fast, but is it as instantaneous as sip of a gimlet and boom? Not quite. So you mentioned about being able to taste bitter compounds in some poisons. So the reason we have these sort of bitter receptors on our tongue is to detect sort of poisons in food.

Is that right? Well, ooh, that's a good, that's a question for those environmental biologists. is that the idea is there's more bitter receptors. And one wonders, you know, and I'm sure that folks in that area have definitely done the research about, you know, is it some kind of co-evolution where if you have that many bitter receptors, when we think a lot of the alkaloids that are plant, we call them plant poisons that are all over the place, a lot of them are alkaloids. And a lot of them are in all kinds of plants. and even things like caffeine. That's a plant alkaloid. Man, is it bitter? Delicious.

Bitter. Right? And so is that it? You know, to kind of be a bit of a warning. And some people, right? That's why you also want to disguise it. Man, again, I sound really that that bitter flavor can be a big giveaway that something's not right.

So if you're going to try to disguise it, right? But yeah, one does wonder, like when you have this kind of, co-evolution or this ecological framework and everyone's in it, is that kind of nature trying to help you out while trying to kill you. So earlier you mentioned Agatha Christie and midsummer murders and things like that. I'm quite a fan of Poirot myself. Oh, I love Paro. Yeah? Do you read or watch a lot of crime fiction? I do. Order and method, Miss Lemon. Order and method. No, I do. I do. Do you think that crime fiction over time is getting better, more accurate in terms of, you know, things like poisonings, but also how forensics are done and things like that? You know, I think there's some that are and some that, you know, take artistic license to move some things along.

And some procedural, you're like, wow, it's really, you know, they've gotten the minutia as far as the details. And sometimes, again, the idea of like, well, we can only find what we're looking for and really the kind of the time scale too, some series really get the time skill, right? You know, some of them you're like, did we just get DNA results back in like the next day? Like, you know, some of those things that you're, you know, hmm. But I think it, you know, it depends on what they're trying to do.

There's definitely been ones where I'm like, I don't know if it quite works that way. But if it helps, you know, it's moving the plot along. There was a great one that Deborah Bloom, who wrote Poisoners Handbook, talked about Skyfall. You know, it's a hydrogen cyanide. So classic kind of spy, I think it doesn't work that way. I mean, it really doesn't work right. And so, but again, you know, I might, you know, it kind of fits in with the mythology of all the violations of physics and science in that series.

So you kind of, you know, you cut it some slack and you're like, okay, I can see. So even though I read all of these, and sometimes they are real wild, right? They don't quite work. I can almost read it with two minds, right? And you're like, oh, I can see why they made that choice. It moved, you know, these things along. And so I think it depends on kind of what they're trying to accomplish with the story. And, you know, and there's definitely been ones where I still am like, ooh, that was great.

not great on the old chemistry facts, but still it was a good story. So what are some of the most common misconceptions that you see in crime fiction? Well, I think when it comes to poisons, it would sometimes be the speed of which they can react. And, you know, that's definitely a big one. You know, the kind of instantaneous fun sip and down at a party. that can be one. And then also the idea that, oh, it was this rare. Sometimes they'll say it's a super rare. And sometimes the rare, they make it seem as if then you wouldn't find it. But if it's rare, sometimes that makes it more suspicious and more identifiable. And I get the rarity because, again, we can only find what we're looking for. So, you know, sometimes with these, I think there's actually a It's called this as a genre, like the English house party in the country and someone is going to die. And it turns out to be like some, you know, the tarotoxin from a South American frog.

And you're like, how did that get? So of course, like the rarity of it is, of course, it's not arsenic. It's not presenting as if it's the standard cyanide arsenic-stric nite that, you know, they're very used to. But the fact that it is that exotic. And I think this might have been a business of a murder where you're not. like, well, who's the only person as keeps these frogs as a pet? And so rare or has access to this rare, small, poisonous octopus, right? That person.

And then immediately, like, anyone out, you know, their immediate close circle that knows they have it. So that's part of the funny thing is that, you know, it's so rare, but it also, that it's hard to find. But then you're like, but that means it has to be this person. So that part is a little fun. again, sometimes it fits with the story, right? And sometimes again, the, you know, if it's how to find it, if they think that sometimes exhumations or, you know, they can check. I'm like, ooh, not sure that would work. Or sometimes they order an exhumation when you're like, but you should still have all the samples that you took from the first one that you could retouch. You know, so, but I know that

the exhumation is like, drama. It's like, you know. So I try to be more like, you know, a fan at that point. But, yeah. You write a column for chemistry worlds. And you've written about things like the insulin murders and things like that. So how do you sort of find a balance between educating people on chemistry and not giving people any ideas? Well, I think, you know, if you have a villainous mindset, that's just your default. Like, if you're going to go, poise, I don't, you know, think that the ideas, I think that, and it's all out there, right?

I think if anything, you know, especially with the trace analysis column, also get into what's the analytical tools, you know, what are they looking for? And so it's, you know, this is how we figure it out. And not to say that there are happy endings, because that's a weird, you know, way to put it. But it's, you know, what's that, that quote, murder will out. You know, it's like, It's, you know, sometimes the cases are resolved. And it may be years down the road. And there may be a real delay. But then there's some, you know, new analysis. And that, it might be some of the interesting ones are, you know, historical forensics. I wrote on some couple of folks that might have been, might have been intentionally poisoned from the Medici court. And then again, the interval of time when you're looking at remains and doing the analytical work, it could be hundreds of years, you know. Then you can look back and go, yeah, there was something not on the up and up. That wasn't, you know, a slow decline. That was an intentional, you know, kind of an action.

But so they're also, they're also sometimes stories of of science revealing that this. is probably what occurred or this, you know, supports that mindset. But yeah, I think it's, I certainly don't try to include how exactly it was done. But again, I think it's, you know, one of those things where as history has shown us over thousands and thousands of years, because formulations for poisons and formulations for anecdotes or thereacts, you know, for those, you know, for those to kind of protect yourself have been around for as long as there's been ways to store information and pass it down. I feel like, so, you know, that kind of villainy, if that's the, or those types of actions, they're just around. People, you know, come up with

good and bad ideas all on their own. They do not. Don't need help from me. Finally, what three things do you think we all should know about poisons? Just about anything can be in poison. You know, there is such a thing as too much of a good thing. And that, again, you can only find what you're looking for. That would be one. And also three is most of the time it's an accident.

You know, I think we are kind of programmed to be, you know, very like, like, oh, poisoning, you know, like hotcakes. But most poisonings, as we've seen with maybe someone who took too many, acetyamide, metaphen, or was like, I know it says only take this much, but I took a couple more. And you're like, well, that is, you know, kind of is an accident. Oh, and if I may add on a fourth one, because you'll see this in fiction, as they say, most, you know, poison is a women's weapon.

Well, crime statistics don't back that up. It's a pretty equal opportunity, if slightly more male presenting. And you'll see that right in a bunch of classic literature and you'll see that repeated. And, you know, some of the most famous poisoners or incidents have not involved people who identify as women at all. So, you know, something to end on a comforting note. Thank you for listening to this episode of Instant Genius. That was Dr. Rachelle Burks. If you want to know more about forensic chemistry, check out her column, trace analysis,

on chemistryworld.com. Or to hear her tell me more about working in a crime lab, as well as how antidotes really work, head over to the Instant Genius Extra podcast. The September issue of BBC Science Focus magazine is out now. Pick up a copy in store or visit sciencefocus.com. This podcast is sponsored by Name, Audio and Focal.

The texture and emotional depth of music can be lost through digital sources or poor signal. Name Audio believes you can have digital precision with analog warmth. Alongside French acoustic specialist focal, Name creates high-end audio systems combining innovation with craftsmanship so you can listen to music,

just as the artist intended. Discover more. At name audio.com. Ambition comes in all shapes and sizes. At First Citizens Bank, we roll with your goals because we're built for what you're building. Fit for your ambition for Citizens Bank.