Tag Archives: Chemicals

Vibrant Viburnum: the fascinating chemistry of fragrant flowers

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There’s a Viburnum carlesii bush (sometimes called Koreanspice) near my front door and, right now, it smells amazing. It only flowers for a relatively short time each year and otherwise isn’t that spectacular – especially in the autumn when it drops its leaves all over the doorstop, and I’m constantly brushing them out of the house.

But it’s all worth it for these few weeks in April, when everyone who has any reason to come anywhere near our door says, ‘ooh, what is that smell? It’s gorgeous!’ We also rear butterflies at this time of year, and they love the flowers once they’ve emerged from their chrysalids. (No, of course this isn’t an excuse to include all my butterfly photos in a post. Painted lady, since you ask.)

But let’s talk chemistry – what is in the Viburnum carlesii’s fragrance? Well, it’s a bit complicated. Fragrances, as you might imagine, often are. We detect smells when volatile (things that vaporise easily) compounds find their way to our noses which are, believe it or not, great chemical detectors.

Well, I say great, many animals have far better smell detection: dogs, of course, are particularly known for it. Their noses have some 300 million scent receptors*, while humans “only” have 5-6 million but, and this is the really fantastic part, by some estimates we’re still able to detect a trillion or so smells. We (and other animals) inhale air that contains odour molecules, and those molecules bind to the receptors in our noses, triggering electrical impulses that our brains interpret as smell.

Most scents aren’t just one molecule, but are actually complex mixtures. Our brains learn to recognise combinations and to associate them with certain, familiar things. It’s not that different from recognising patterns of sound as speech, or patterns of light as images, it’s just that we often don’t think of smell in quite the same way.

Viburnum carlesii flowers have a fragrance often described as sweet and spicy.

So my Viburnum bush – and the flowers I’ve cut and put on my desk – is actually pumping out loads of different molecules right now. After a bit of hunting around, I tracked them down to (brace yourself for a list of chemical names) isoeugenol, eugenol, methyleugenol, 4-allylsyringol, vinyl-guaiacol and methyl nicotinate, plus the old favourites methyl salicylate (this stuff turns up everywhere), methyl benzoate (so does this), indole, cinnamic aldehyde and vanillin, and then some isovaleraldehyde, acetoin, hexanal, (Z)-3-hexen-1-ol and methional.

Phew.

Don’t worry, I’m not going to talk about the chemistry of all of those. But just for a moment consider how wondrous it is that our noses and brains work together to detect all of those molecules, in their relevant quantities, and then send the thought to our conscious mind that oh, hey, the Viburnum is flowering! (It’s also pretty astonishing that, in 2021, I can just plug all those names into a search engine and, with only a couple of exceptions, get all sorts of information about them in seconds – back in the old days when I was studying chemistry, you had to use a book index, and half the time the name you wanted wasn’t there. You kids don’t know how good you’ve got it, I’m telling you.)

Anyway, if you glance at those names, you’ll see eugenol popping up quite a bit, so let’s talk about that. It’s a benzene ring with a few other groups attached, and lots of chemicals like this have distinctive smells. In fact, we refer to molecules with these sorts of ring structures as “aromatic” for this exact, historical reason – when early chemists first isolated them, they noticed their distinctive scents.

Eugenol is an aromatic compound, both in terms of chemistry and fragrance (image source)

In fact there are several groups of molecules in chemistry that we tend to think of as particularly fragrant. There are esters (think nail polish and pear drops), linear terpenes (citrus, floral), cyclic terpenes (minty, woody), amines (fishy, rot) and the aromatics I’ve just mentioned.

But back to eugenol: it’s a yellowish, oily liquid that can be extracted from plants such as nutmeg, cloves, cinnamon, basil and bay leaves. This might give you an idea of its scent, which is usually described as “spicy” and “clove-like”.

Not surprisingly, it turns up in perfumes, and also flavourings, since smell and flavour are closely linked. It’s also a local antiseptic and anaesthetic – you may have used some sort of eugenol-based paste, or perhaps just clove oil, if you’ve ever had a tooth extracted.

Plants, of course, don’t go to the trouble and biological expense of making these chemicals just so that humans can walk past and say, “ooh, that smells nice!” No, the benefit for the plant is in attracting insects, which (hopefully) help with pollination. Which explains why my butterflies like the flowers so much. (Another butterfly pic? Oh well, since you insist.) Eugenol, it turns out, is particularly attractive to various species of orchid bee, which use it to synthesise their own pheromones. Nature’s clever, isn’t she?

By the way, notice I mentioned anaesthetics back there? Eugenol turns out to be too toxic to use for this in large quantities, but the study of it did lead to the development of the widely-used drug propofol which, sadly, is pretty important right now – it’s used to sedate mechanically ventilated patients, such as those with severe COVID-19 symptoms. You may have seen some things in the news earlier this year about anaesthetic supply issues, precisely for this reason.

Isoeugenol has the same “backbone” as eugenol, with just a difference to the position of the C=C bond on the right. (image source)

Back in that list of chemical names, you’ll see “eugenol” forming parts of other names, for example isoeugenol. This points back to a time when chemicals tended to be named based on their origins. Eugenol took its name from the tree from which we get oil of cloves, Eugenia, which was in turn named after Prince Eugene of Savoy – a field marshal in the army of the Holy Roman Empire. And then other molecules with the same “backbone” were given the same name with prefixes and suffixes added on to describe their differences. As I said in my last post, this sort of naming system it was eventually replaced with more consistent rules, but a lot of these older substances have held onto their original names.

Still, regardless of what we call the chemicals, the flowers smell delightful. I’m off to replenish the vase on my desk while I still can. Roll on May, vaccines and (hopefully) lockdown easing!

Take care and stay safe.

*it’s even been suggested dogs’ super-powered sense of smell might be able to detect COVID-19 infections.

If you’re studying chemistry, have you got your Pocket Chemist yet? Why not grab one? It’s a hugely useful tool, and by buying one you’ll be supporting this site – it’s win-win! If you happen to know a chemist, it would make a brilliant stocking-filler! As would a set of chemistry word magnets!

Like the Chronicle Flask’s Facebook page for regular updates, or follow @chronicleflask on Twitter. Content is © Kat Day 2021. You may share or link to anything here, but you must reference this site if you do. If you enjoy reading my blog, and especially if you’re using information you’ve found here to write a piece for which you will be paid, please consider buying me a coffee through Ko-fi using the button below.
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Want something non-sciency to distract you from, well, everything? Why not check out my fiction blog: the fiction phial.

 

Confusing chemical names: why do some sound so similiar?

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It’s the end of March as I write this and, here in the UK at least, things are starting to feel a little bit hopeful. We’ve passed the spring equinox and the clocks have just gone forward. Arguments about the rights and wrongs of that aside, it does mean daylight late into the day, which means more opportunities to get outside in the evenings. Plus, of course, COVID-19 vaccines are rolling out, with many adults having had at least their first dose.

Some COVID-19 vaccines contain polyethylene glycol (PEG), a safe substance found in toothpaste, laxatives and other products, according to Science magazine and health expertsAh, yes. Speaking of vaccines… a couple of weeks ago I spotted a rather strange item trending on Twitter. The headline was: “Some COVID-19 vaccines contain polyethylene glycol (PEG), a safe substance found in toothpaste, laxatives and other products, according to Science magazine and health experts.”

Apart from being a bit of mouthful, this seemed like the most non-headline ever. And also, isn’t it the kind of thing that might raise suspicions in a certain mind? In a, “yeah, and why do they feel the need to tell us that, huh” sort of way?

Why on earth did it even exist?

A little bit of detective work later (by which I mean me tweeting about it and other people kindly taking the time to enlighten me) and I had my answer. The COVID-19 sceptic Alex Berenson had tweeted that the vaccine(s) contained antifreeze. Several people had immediately responded to say that, no, none of the vaccine formulations contain antifreeze. Antifreeze is ethylene glycol, which is definitely not the same thing as polyethylene glycol.

I’m not going to go much further into the vaccine ingredients thing, because actual toxicologists weighed in on that, and there’s nothing I (not a toxicologist) can really add. But this did get me thinking about chemical names, how chemists name compounds, and why some chemical names seem terrifyingly long while others seem, well, a bit silly.

A lot of the chemical names that have been around for a long time are just… names. That is, given to substances for a mixture of reasons. They do usually have something to do with the chemical makeup of the thing in question, but it might be a bit tangential.

formic acid, HCOOH, was first extracted from ants

For example, formic acid, HCOOH, takes its name from the Latin word for ant, formica, because it was first isolated by, er, distilling ant bodies (sorry, myrmecologists). On the other hand limestone, CaCO3, quicklime, CaO, and limewater, a solution of Ca(OH)2, all get their names from the old English word lim, meaning “a sticky substance,” which is also connected to the Latin limus, from which we get the modern word slime — because lime (mostly CaO) is the sticky stuff used to make building mortar.

The trouble with this sort of system, though, is that it gets out of control. The number of organic compounds listed in the American Chemical Society‘s index is in excess of 30 million. On top of which, chemists have an annoying habit of making new ones. Much as some people might think forcing budding chemists to memorise hundreds of thousands of unrelated names is a jolly good idea, it’s simply not very practical (hehe).

It’s the French chemist, Auguste Laurent, who usually gets most of the credit for deciding that organic chemistry needed a system. He was a remarkable scientist who discovered and synthesised lots of organic compounds for the first time, but it was his proposal that organic molecules be named according to their functional groups that would change things for chemistry students for many generations to come.

Auguste Laurent (image source)

Back in 1760 or so, memorising the names of substances wasn’t that much of a chore. There were half a dozen acids, a mere eleven metallic substances, and about thirty salts which were widely known and studied. There were others, of course, but still, compared to today it was a tiny number. Even if they were all named after something to do with their nature, or the discoverer, or a typical property, it wasn’t that difficult to keep on top of things.

But over the next twenty years, things… exploded. Sometimes literally, since health and safety wasn’t really a thing then, but also figuratively, in terms of the number of compounds being reported. It was horribly confusing, there were lots of synonyms, and the situation really wasn’t satisfactory. How can you replicate another scientist’s experiment if you’re not even completely sure of their starting materials?

In 1787 another French chemist, Guyton de Morveau, suggested the first general nomenclature — mostly for acids, bases and salts — with a few simple principles:

  • each substance should have a unique name, as short and specific as possible
  • the name should reflect what the substance consisted of, that is, describe its “composing parts”
  • unknown substances should be assigned names with no particular meaning, being sure not to suggest something false about the substance (if you know it’s not an acid, for example, don’t name it someinterestingname acid)
  • new names should be based on old languages, such as Latin

His ideas were accepted and adopted by most chemists at the time, although a few did attack them, claiming they were “barbarian, incomprehensible, and without etymology” (reminds me of some of the arguments I’ve had about sulfur). Still, his classification was eventually made official, after he presented it to the Académie des Sciences.

Chemists needed a naming system that would allow them to quickly identify chemical compounds.

However, by the middle of the 1800s, the number of organic compounds — that is, ones containing carbon and hydrogen — was growing very fast, and it was becoming a serious problem. Different methods were proposed to sort through the messy, and somewhat arbitrary, accumulation of names.

Enter Auguste Laurent. His idea was simple: name your substance based on the longest chain of carbon atoms it contains. As he said, “all chemical combinations derive from a hydrocarbon.” There was a bit more to it, and he had proposals for dealing with specific substances such as amines and aldehydes, and of course it was in French, but that was the fundamental idea.

It caused trouble, as good ideas so often do. Most of the other chemists of the time felt that chemical names should derive from the substance’s origins. Indeed, some of the common ones that chemistry professors are clinging onto today still do. For example, the Latin for vinegar is acetum, from which we get acetic acid. But, since organic chemistry was increasingly about making stuff, it didn’t entirely make sense to name compounds after things they might have come from, if they’d come from nature — even when they hadn’t.

So, today, we have a system that’s based on Laurent’s ideas, as well as work by Jean-Baptiste Dumas and, importantly, the concept of homology — which came from Charles Gerhardt.

Homology means putting organic compounds into “families”. For example, the simplest family is the alkanes, and the first few are named like this:

Like human families, chemical families share parts of their names and certain characteristics.

The thing to notice here is that all the family members have the same last name, or rather, their names all end with the same thing: “ane”. That’s what tells us they’re alkanes (they used to be called paraffins, but that’s a name with other meanings — see why we needed a system?).

So the end of the name tells us the family, and the first part of the name tells us about the number of carbons: something with one carbon in it starts with “meth”. Something with five starts with “pent”, and so on. We can go on and on to much bigger numbers, too. It’s a bit like naming your kids by their birth order, not that anyone would do such a thing.

There are lots of chemical families. The alcohols all end in “ol”. Carboxylic acids all end in “oic acid” and ketones end in “one” (as in bone, not the number). These endings tell us about certain groups of atoms the molecules all contain — a bit like everyone in a family having the same colour eyes, or the same shaped nose.

A chemist that’s learned the system can look at a name like this and tell you, just from the words, exactly which atoms are present, how many there are of each, and how they’re joined together. Which, when you think about it, is actually pretty awesome.

Which brings me back to the start and the confusion of glycols. Ah, you may be thinking, so ethylene glycol and polyethylene glycol are part of the same family? Their names end with the same thing, but they start differently?

Well, hah, yes and no. You remember a moment ago when I said that there are still some “common” names in use, that came from origins — for example acetic acid (properly named ethanoic acid)? Well, these substances are a bit like that. The ending “glycol” originates from “glycerine” because the first ones came from, yes, glycerine — which you get when fats are broken down.

Polyethylene glycol (PEG) is a polymer, with very different properties to ethylene glycol (image source)

Things that end in glycol are actually diols, that is, molecules which contain two -OH groups of atoms (“di” meaning two, “ol” indicating alcohol). Ethylene glycol is systematically named ethane-1,2-diol, from which a chemist would deduce that it contains two carbon atoms (“eth”) with alcohol groups (“ol”) on different carbons (1,2).

Polyethylene glycol, on the other hand, is named poly(ethylene oxide) by the International Union of Pure and Applied Chemistry (IUPAC), who get the final say on these things. The “poly” tells us it’s a polymer — that is, a very long molecule made by joining up lots and lots of smaller ones. In theory, the “ethylene oxide” bit tells us what those smaller molecules were, before they all got connected up to make some new stuff.

Okay, fine. So what’s ethylene oxide? Well, you see, that’s not quite a systematic name, either. Ethylene oxide is a triangular-shaped molecule with an oxygen atom in it, systematically named oxirane. Why poly(ethylene oxide), and not poly(oxirane), then? Mainly, as far as I can work out, to avoid confusion with epoxy resins and… look, I think we’ve gone far enough into labyrinth at this point.

The thing is, polyethylene glycol is usually made from ethylene glycol. Since everyone tends to call ethylene glycol that (and rarely, if ever, ethane-1,2-diol), it makes sense to call the polymer polyethylene glycol. Ethylene glycol makes polyethylene glycol. Simple.

Plastic bags are made from polythene, which has very different properties to the ethene that’s used to make it.

Polymers are very different to the molecules they’re made from. Of course they are, otherwise why bother? For example, ethene (also called ethylene, look, I’m sorry) is a colourless, flammable gas at room temperature. Poly(ethylene) — often just called polythene — is used to make umpteen things, including plastic bags. They’re verrrrry different. A flammable gas wouldn’t be much use for keeping the rain off your broccoli and sourdough.

Likewise, ethylene glycol is a colourless, sweet-tasting, thick liquid at room temperature. It’s an ingredient in some antifreeze products, and is, yes, toxic if swallowed — damaging to the heart, kidneys and central nervous system and potentially fatal in high enough doses. Polyethylene glycol, or PEG, on the other hand, is a solid or a liquid (depending on how many smaller molecules were joined together) that’s essentially biologically inert. It passes straight through the body, barely stopping along the way. In fact, it’s even used as a laxative.

So the headlines were accurate: PEG is “a safe substance found in toothpaste, laxatives and other products.” It is non-toxic, and describing it as “antifreeze” is utterly ridiculous.

In summary: different chemicals, in theory, have nice, logical, tell-you-everything about them names. But, a bit like humans, some of them have obscure nicknames that bear little resemblance to their “real” names. They will insist on going by those names, though, so we just need to get on with it.

The one light in this confusingly dark tunnel is the internet. In my day (croak) you had to memorise non-systematic chemical names because, unless you had a copy of the weighty rubber handbook within reach, there was no easy way to look them up. These days you can type a name into Google (apparently other search engines are available) and, in under a second, all the names that chemical has ever been called will be presented to you. And its chemical formula. And multiple other useful bits of information. It’s even possible to search by chemical structure these days. Kids don’t know they’re born, I tell you.

Anyway, don’t be scared of chemical names. They’re just names. Check what things actually are. And never, ever listen to Alex Berenson.

And get your vaccine!

If you’re studying chemistry, have you got your Pocket Chemist yet? Why not grab one? It’s a hugely useful tool, and by buying one you’ll be supporting this site – it’s win-win! If you happen to know a chemist, it would make a brilliant stocking-filler! As would a set of chemistry word magnets!

Like the Chronicle Flask’s Facebook page for regular updates, or follow @chronicleflask on Twitter. Content is © Kat Day 2021. You may share or link to anything here, but you must reference this site if you do. If you enjoy reading my blog, and especially if you’re using information you’ve found here to write a piece for which you will be paid, please consider buying me a coffee through Ko-fi using the button below.
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Want something non-sciency to distract you from, well, everything? Why not check out my fiction blog: the fiction phial.

 

The Chronicles of the Chronicle Flask: 2018

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As has become traditional, I’m finishing off this year with a round-up of 2018’s posts. It’s been a good year: a few health scares which turned out to be nothing much to worry about, one which turned out to be a genuine danger, a couple of cool experiments and some spectacular shiny balls. So without further ado, here we go…

Things were a bit hectic at the start of this year (fiction writing was happening) and as a result January was quiet on the blog. But not on the Facebook page, where I posted a couple of general reminders about the silliness of alkaline diets which absolutely exploded, achieving some 4,000 shares and a reach (so Facebook tells me anyway) of over half a million people. Wow. And then I posted a funny thing about laundry symbols which went almost as wild. It’s a strange world.

February featured BPA: an additive in many plastics.

In February I wrote a piece about BPA (Bisphenol A), which was the chemical scare of the day. There’s always one around January/February time. It’s our penance for daring to enjoy Christmas. Anyway, BPA is a chemical in many plastics, and of course plastic waste had become – and remains – a hot topic. BPA is also used in a number of other things, not least the heat sensitive paper used to produce some shopping receipts. It’s not a harmless substance by any means, but it won’t surprise anyone to learn that the risks had, as is usually the case, been massively overstated. In a report, the European Food Safety Authority said that the health concern for BPA is low at their estimated levels of exposure. In other words, unless you’re actually working with it – in which case you should have received safety training – there’s no need to be concerned.

In March I recorded an episode for the A Dash of Science podcast, and I went on to write a post about VARD, which stands for Verify, Author, Reasonableness and Date. It’s my quick and easy way of fact-checking online information – an increasingly important skill these days. Check out the post for more info.

April ended up being all about dairy and vitamin D.

April was all about dairy after a flare-up on Twitter on the topic, and went on to talk about vitamin D. The bottom line is that everyone in the UK should be taking a small vitamin D supplement between about October and March, because northern Europeans simply can’t make vitamin D3 in their skin during these months (well, unless they travel nearer to the equator), and it’s not a nutrient we can easily get from our food. Are you taking yours?

May featured fish tanks, following a widely reported story about a fish-owner who cleaned out his tank and managed to release a deadly toxin that poisoned his entire family. Whoops. It turns that this was, and is, a real risk – so if you keep fish and you’ve never heard of this before, do have a read!

In June I wrote about strawberries, and did a neat experiment to show that strawberries could be used to make pH indicator. Who knew? You do, now! Check it out if you’re looking for some chemistry to amuse yourself over the holidays (I mean, who isn’t?). Did you know you can make indicators from the leaves of Christmas poinsettia plants, too?

Slime turned up again in July. And December. And will probably keep on rearing its slimy head.

July brought a subject which has turned up again recently: slime. I wrote about slime in 2017, too. It’s the gift that keeps on giving. This time it flared up because the consumer magazine and organisation Which? kept promoting research that, they claimed, showed that slime toys contain dangerous levels of borax. It’s all rather questionable, since it’s not really clear which safety guidelines they’re applying and whether they’re appropriate for slime toys. Plus, the limits that I was able to find are migration limits. In other words, it’s not appropriate to measure the total borax content of the slime and declare it dangerous – they should be looking at the amount of borax which is absorbed during normal use. Unless your child is eating slime (don’t let them do that), they’re never going to absorb enough borax to do them any harm. In other words, it’s a storm in a slimepot.

August was all about carbon dioxide, after a heatwave spread across Europe and there was, bizarrely, a carbon dioxide shortage which had an impact on all sorts of things from fizzy drinks to online shopping deliveries. It ended up being a long-ish post which spanned everything from the formation of the Earth, the discovery of carbon dioxide, fertilisers and environmental concerns.

September featured shiny, silver balls.

In September I turned my attention to a chemical reaction which is still to this day used to coat the inside of glass decorations with a thin layer of reflective silver, and has connections with biochemistry, physics and astronomy. Check it out for some pretty pictures of silver balls, and my silver nitrate-stained fingers.

In October I was lucky enough to go on a ‘fungi forage’ and so, naturally, I ended up writing all about mushrooms. Did you know that a certain type of mushroom can be used to make writing ink? Or that some mushrooms change colour when they’re damaged? No? You should go back and read that post, then! (And going back to April for a moment, certain mushrooms are one of the few sources of vitamin D.)

Finally, November ended up being all about water, marking the 235th anniversary of the day that Antoine Lavoisier formally declared water to be a compound. It went into the history of water, how it was proven to have the formula H2O, and I even did an experiment to split water into hydrogen and oxygen in my kitchen – did you know that was possible? It is!

As December neared, the research for my water piece led me to suggest to Andy Brunning of Compound Interest that this year’s Chemistry Advent might feature scientists from the last 24 decades of chemistry, starting in the 1780s (with Lavoisier and Paulze) and moving forward to the current day. This turned out to be a fantastic project, featuring lots of familiar and not quite so-familiar scientists. Do have a look if you didn’t follow along during December.

And that’s it for this year. I hope it’s been a good one for all my readers, and I wish you peace and prosperity in 2019! Suggestions for the traditional January Health Scare, anyone? (Let’s hope it’s not slime again, I’m getting really tired of that one now…)

Like the Chronicle Flask’s Facebook page for regular updates, or follow @chronicleflask on Twitter. All content is © Kat Day 2018. You may share or link to anything here, but you must reference this site if you do.

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The Chronicles of the Chronicle Flask: 2017

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We’ve made it! Not only to 2018 (which was starting to look doubtful earlier in the year), but also to the Chronicle Flask’s 100th post. Which doesn’t seem that many, really, but since posts on here frequently run to 1500 words, that adds up to a rather more impressive-sounding 150,000 words or so. I mean, that’s like… half a Brandon Sanderson novel. Oh.

Anyway, it’s time for a yearly round-up. Here goes!

Last January I began with a post about acrylamide. We’d all been enjoying lots of lovely crispy food over Christmas; it was time to tell us about the terrible dangers of such reckless indulgence. The newspapers were covered with pictures of delicious-looking chips, toast and roast potatoes alongside scary headlines such as:  “Crunchy toast could give you cancer, FSA warns”. The truth was not quite so dramatic. Acrylamide does form when foods are cooked to crispiness, and it is potentially harmful, but the quantities which form in food are tiny, and very unlikely to cause you any serious harm unless you literally live on nothing but burnt toast. The FSA (Food Standards Agency) hadn’t significantly revised their guidelines, it turned out, but were in fact only suggesting that the food industry should be mindful of acrylamide levels in food and seek to reduce them as much as possible. That wouldn’t have made for quite such a good “your food is going to killllll you!” story though, I suppose.

In February the spikey topic of vaccination came up. Again. Vaccines are awesome. They protect us from deadly diseases. No, I don’t want to hear any nonsense about “Big Pharma“, and I definitely don’t want to hear how “natural immunity” is better. It’s not. At best, it might provide a similar level of protection (but not in every case), but it comes with having to suffer through a horrible, dangerous disease, whereas vaccination doesn’t. It ought to be a no-brainer. Just vaccinate your kids. And yourself.

It was Red Nose Day in the UK in March, which brought some chemistry jokes. Turns out all the best ones aren’t gone, after all. Did you hear about the PhD student who accidentally cooled herself to absolute zero? She’s 0K now.

April brought a post which ought to have been an April Fool’s joke, but wasn’t. Sceptics often point out that homeopathy is just sugar and water, but the trouble is, sometimes, it’s not. There’s virtually no regulation of homeopathy. As far as I’ve been able to establish, no one tests homeopathic products; no one checks the dilutions. Since a lot of the starting materials are dangerously toxic substances such as arsenic, belladona, lead and hemlock, this ought to worry people more than it does. There has been more than one accidental poisoning (perhaps most shockingly, one involving baby teething products). It really is time this stuff was banned, maybe 2018 will be the year.

In May I turned to something which was to become a bit of a theme for 2017: alkaline water. It’s not so much that it doesn’t do anything (although it really doesn’t), more the fact that someone is charging a premium for a product which you could literally make yourself for pennies. It’s only a matter of dissolving a pinch of baking soda (sodium bicarbonate) in some water.

June brought a selection of periodic tables because, well, why not? This is a chemistry blog, after all! And now we’ve finally filled up period seven they do have a rather elegant completness. 2019, by the way, has just been announced as the International Year of the Periodic Table of Chemical Elements, to coincide with IUPAC’s 100th anniversary and the 150th anniversary of Mendeelev’s discovery of periodicity (his presentation, The Dependence Between the Properties of of the Atomic Weights of the Elements, was made on 6th March 1869). Looks like 2019 will be an exciting year for chemists!

In July it was back to the nonsense of alkaline diets again, when Robert O. Young was finally sentenced to 3 years, 8 months in custody for conning vulnerable cancer patients into giving him large sums of money for ineffective and dangerous treatments. Good. Moving on.

August brought me back to a post that I’d actually started earlier in the year when I went to a March for Science event in April. It was all about slime, and August seemed like a good time to finally finish it, with the school holidays in full swing – what could be more fun on a rainy day at home than making slime? Slime was a bit of a 2017 craze, and there have been a few stories featuring children with severely irritated skin. But is this likely to be caused by borax? Not really. Turns out it’s actually very safe. Laundry detergents in general, not so much. In short, if you want to make slime the traditional way with PVA glue and borax, fill your boots. (Not really – your parents will be uninpressed.)

In September it was back to quackery: black salve. A nasty, corrosive concoction which is sold as a cancer cure. It won’t cure your cancer. It will burn a nasty great big hole in your skin. Do not mess with this stuff.

October carried on in a similar vein, literally. This time with a piece about naturopaths recommending hydrogen peroxide IVs as a treatment for lots of things, not least – you guessed it – cancer. Yes, hydrogen peroxide. The stuff you used to bleach hair. Intraveneously. Argh.

The puking pumpkin!

The end of the month featured a far better use for hydrogen peroxide, that of the puking pumpkin. Definitely one to roll out if, for any reason, you ever find yourself having to demonstrate catalysis.

November brought us, somewhat unseasonally, to tomatoes. Where is the best place to store them? Fridge or windowsill? Turns out the answer involves more chemistry than you might have imagined.

And then, finally, December. Looking for a last-minute Christmas gift? Why not buy a case of blk water? I mean, other than it’s an exorbitantly priced bottle of mysterious black stuff which doesn’t do any of the things it claims to do, and might actually get its colour from coal deposits, that is.

And that, dear friends and followers, is it for 2017! Happy New Year! Remember to be sceptical when the inevitable “deadly food” story appears in a few weeks….

Like the Chronicle Flask’s Facebook page for regular updates, or follow @chronicleflask on Twitter. All content is © Kat Day 2018. You may share or link to anything here, but you must reference this site if you do.

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Unsafe slime? How bad is borax, really?

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Slime is a fun bit of chemistry that anyone can do – but how safe is it?

Edit, December 2018: I’ve written another, more recent, slime post which specifically addresses some of the recent safety claims made in the media. Read it here.

It’s August, which means it’s the school summer holidays in the UK and, as is traditional, it’s been pouring with rain. This has left many a cabin-fevered child searching for ways to amuse themselves.

Start hunting around the internet for things to do and it’s not long before the concept of the “kitchen science” experiment turns up. There are actually loads of these, and it’s even possible to do some of them without permanently damaging anyone’s eardrums, dusting every surface with cornflour and leaving a parent rocking in the corner muttering “why did I encourage this?” over and over to themselves.

Which brings me to slime – surely the go-to fun science experiment. What’s not to love about taking some of that white, runny PVA glue found in gallon bottles in school classrooms everywhere and magically turning it into glorious, gloopy slime? Add some food colouring and you can even have coloured slime! Add glitter and… well you get the idea.

Many YouTubers love this stuff. A quick search for “make your own slime” turns up pages and pages of videos, giving instructions as to how to do just that.

In fact, it seems that slime-making is currently a bit of a craze, with children all over the world making all kids of different types. There’s unicorn slime, rainbow slime, fluffy slime – you name it. Brilliant, you might think, a whole generation of youngsters interested in chemistry. What’s not to like about that?

Well, as a few news reports have recently pointed out, there might be a problem if children are handling lots of borax, or certain other chemicals.

Polyvinyl alcohol

Slime, you see, is a really nice example of polymerisation – the same process that goes on when plastics are made. PVA glue, the usual starting material, is a polymer itself. The letters PVA stand for polyvinyl alcohol (its systematic name is poly(1-hydroxyethylene)), but literally no one calls it that, not even A-level chemistry teachers forced, kicking and screaming, to follow IUPAC naming conventions).

PVA is a long chain of carbon atoms with alternating CH2 groups and alcohol, OH, groups. As anyone who’s ever handled it will know, it’s quite runny. Thick, yes, but still runny. Basically, it’s a liquid.

But if you mix it with borax, aka sodium tetraborate, some magic happens. And when I say magic, I mean chemistry. The chains of atoms become linked together (edit July 2018: I originally said via hydrogen bonds but turns out that’s not quite right – check out this page on c&en for more info), and as a result the new substance is a lot more solid. But it’s not quite solid. At least, not in the sense of something that keeps its own shape. No, this is weird, peculiar, stuff that sits somewhere in between solid and liquid.

Borax joins the chains of PVA together.

There’s something tactilely pleasing about slime. Put it in your hands and it feels cool and slightly moist – your fingers slide over and through it with a sort of squeaky sensation. Leave it alone for a few minutes and it flows to take the shape of its container, forming a perfect, mirror finish on its surface. Tip the pot over, and it will gradually creep toward the edge.

It is safe to handle. Here are my hands, handling it (we made this at the March for Science in Bristol back in April). You will notice that my skin is not falling off.

It’s white unless you dye it. We went for red, which is pleasingly disturbing.

I did, though, wash my hands after I took that photo. And that’s because, while the PVA is pretty harmless (as you know if, like me, you spent your primary school days painting your hands with glue just so you could peel it off later) the borax isn’t. At least, not entirely.

Before I go any further, let’s be clear: lots of things aren’t “entirely” safe. Most of the cleaning products in the average kitchen and bathroom have warning levels of varying degrees of severity on them, and we don’t think too much about it. Even things that are designed to be in contact with skin, like hand soap and shampoo, usually have warnings about eye irritation and statements like “if irritation occurs, discontinue use”. Even water is deadly in the wrong context (don’t try inhaling too much of it, for example). So when I say not entirely safe, I don’t mean to suggest that panic needs to ensue if your child has so much as looked at a borax solution.

Borax has traditionally been used in several household products, although admittedly more in the US than in the UK. Most people know it as a laundry additive, where it softens water, brightens whites and inhibits the growth of the bacteria and fungi which can make clothes stinky.

It’s not considered a lethal compound, in the sense that you’d have to eat a large quantity – far more than anyone might reasonably consume by accident – before it became deadly, and you’d almost certainly throw up long before then. Borax can irritate the skin (but see note at the end), and inhalation of the dust is well known to irritate the lungs. This is more of a concern for people working with borax on an industrial scale day in and day out – but it could become an issue if, say, someone were making slime every single day using large quantities of borax (not recommended).

Then there’s another concern. If borax is exposed to hydrochloric acid, it forms boric acid. Long-term exposure to boric acid can cause kidney damage and fertility problems, both in men and women. It’s also potentially teratogenic, which means it could cause harm to an unborn child. Borax and boric acid are not the same thing but, of course, our stomachs contain hydrochloric acid. Therefore, if you swallow borax, you’re effectively exposed to boric acid.

Frequent exposure to borax might cause skin irritation (see note at end)

These risks are the reason borax was added to the Substance of Very High Concern (SVHC) candidate list on 16 December 2010, which is the first step in restricting use of the chemical within the European Union. As far as I can establish, it’s still a “candidate”, but the European Chemicals Agency substance information card does state that borax may “damage fertility or the unborn child”.

Now, the chances of achieving the levels involved in “long-term exposure” from occasionally handling borax solutions are slim to none. It’s safe to handle dilute borax solutions (see notes at the end). Indeed, borax is even approved as a food preservative in the EU (E285). To put it into context, alcohol (ethanol) also causes organ damage and is a known teratogen and a carcinogen (which borax isn’t) and that turns up in all sorts of things we’re regularly in contact with, everything from antiseptic hand gels to mouthwashes to drinks (and it’s also approved as a food additive, E1510 – which is good news if you like liqueur chocolates).

I personally have no concerns about handling dry borax in small quantities to make up solutions myself. However, I wouldn’t let children do that part. Once made I’d consider the solution safe, so long as children were supervised and weren’t doing anything really silly like drinking it. I’d also tell children to wash their hands after handling the slime and, if I thought they had sensitive skin for any reason (eczema, say) I’d suggest plastic gloves.

Borax is easy to buy online.

Because of the European Regulations, it theoretically shouldn’t be that easy to get hold of borax in the UK. But I found it for sale on Amazon.co.uk. The listing says that it “can only be purchased by Professionals and by trade and business users,” (sic) but I ordered some and there were no checks. A plastic bag full of borax powder (the decahydrate, Na2B4O7.10H2O) arrived within a few days.

Most of the news reports doing the rounds have involved children suffering from severe skin irritation. For example, in February this year a woman from Manchester posted photos of chemical burns on her daughter’s hands online as a warning to other parents. However, looking into the details of that story it turns out that she wasn’t using borax. In fact, she used fabric detergent “as an alternative”.

Take a look at pretty much type of fabric detergent and you’ll find hazard warnings, usually indicating it’s corrosive and definitely saying “keep out of reach of children”. Those are there for a reason. Fabric detergent is designed to remove grease and  stains. In other words, to break down fats and proteins, and guess what your skin is made of? Yep. Don’t get neat fabric detergent on your hands. Even if your skin isn’t particularly sensitive, it’s almost certainly going to irritate it.

Fabric detergents are usually labelled corrosive.

Bottom line: don’t use fabric detergent as a borax alternative to make slime, because there’s a real risk that enough of it could get onto your (or your child’s) skin that it could irritate.

When it comes to borax itself, if I understand things correctly, it’s not actually restricted in the EU – including the UK – yet. (I might have this wrong – do correct me if you think I have.) It’s not something you can pop to the supermarket and buy, but as we’ve established you can buy it online fairly easily.

Borax solutions are extremely unlikely to cause harm, if used sensibly (boron chemist David Schubert agrees, see note at the end). But, once again: if you’re doing this experiment it’s best not to let children make up the solution – an adult should do that part.

A sensible quantity is about 1 gram of borax in 25 millilitres of warm water (for those without a metric scale: one level teaspoon of borax in half a cup measure of water). This will actually polymerise quite a bit of PVA – you don’t need that much. I recommend making the borax solution in a labelled plastic cup which you should throw away afterwards. Don’t leave it anywhere where someone might mistake it for their drink! Once the solution is made just add a little bit to some PVA in another plastic cup, give it a good stir with a spoon or a lolly stick, and the magic (chemistry) will happen. Add food colouring if you like (be aware that it can stain!) and enjoy the slimy goodness. (See additional note for teachers & technicians at the end.)

Do supervise any and all slime-making, don’t let children handle slime all day, every day, and if you know they have sensitive skin, make them wear plastic gloves. Make them wash their hands before they eat or drink anything.

If a child has made slime somewhere else, at a party or a science club, say, and they bring it home, again, there’s no need to worry. They can play with it perfectly safely. Don’t let them leave it on a radiator, though. That will end in disaster.

I am not a fan of the “it might be a bit dangerous, so no one should ever try it” mentality. I mean, that’s just no fun, is it? But I’m also not a fan of unnecessary risks – because trips to hospital are equally no fun. So if you want to try this experiment, I’ve summarised my guidance in this graphic.

Stay safe with slime by following this guidance

And if you want a even safer slimy experiment, and you can bear the mess, I suggest mixing cornflour with just enough water to make a thick paste in a shallow tray. Then let your kids stick their fingers in it, bounce things off it, and generally play with it. (Check out this link to find out more about why it behaves as it does.) I’m told it makes an even better mixture if you add basil seeds.

Have fun this summer, stay safe, and don’t eat the slime!

Note for teachers and technicians:
This post is aimed at people who might be making slime at home, and hence not have easy access to CLEAPSS guidelines. Anyone doing the experiment with students in school should, of course, refer to their department’s risk assessments and policies. For the record, at the time of writing, CLEAPSS classify 0.2M or 40g/dm³ (or more dilute) borax solutions as “low hazard”.

Edit: 15th August 2017:
After I wrote and published this post I was contacted by someone who specialises in boron chemistry, David Schubert. Now, if anyone knows about boron safety, it’ll be the guy who spends all day working with boron-based chemicals! He told me that borax has been shown to be safe for skin contact. He also said that you absorb less boron through intact skin than you consume by eating a normal, healthy diet (boron is a naturally-occurring trace-mineral – nuts and pulses are good sources), and even provided me with a link to a research paper on the subject. I asked him about the high pH of boron solutions, since alkaline solutions can be irritating in general, and he told me that borax solutions are less alkaline than sodium carbonate and not at all irritating to skin. At this point I will stress that when we’ve seen reports of children suffering skin irritation after making slime, it hasn’t been clear exactly what they’ve been handling. It’s very likely they were adding other chemicals to their slime, and it was actually one of those causing the irritation. Perhaps they developed an allergy to something. It’s impossible to say. Either way, the bottom line is that borax solutions are pretty safe – there’s no need to worry. (Still don’t drink them though!)

Like the Chronicle Flask’s Facebook page for regular updates, or follow @chronicleflask on Twitter. All content is © Kat Day 2017. You may share or link to anything here, including the images, but you must reference this site if you do.

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Hazardous homeopathy: ‘ingredients’ that ought to make you think twice

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Would you take a medicine made with arsenic? Or deadly nightshade? Lead? Poison ivy?

You’d ask some serious questions first, at least, wouldn’t you? Is it definitely safe? Or, more accurately, are the odds better than even that it will make me better without causing horrible side-effects? Or, you know, killing me?

There ARE medicines that are legitimately made from highly toxic compounds. For example, the poison beloved of crime writers such as Agatha Christie, arsenic trioxide, is used to treat acute promyelocytic leukemia in patients who haven’t responded to other treatments. Unsurprisingly, it’s not without risks. Side-effects are unpleasant and common, affecting about a third of patients who take it. On the other hand, acute promyelocytic leukemia is fatal if untreated. A good doctor would talk this through with a patient, explain both sides, and leave the final choice in his or her properly-informed hands. As always in medicine, it’s a question of balancing risks and benefits.

Would you trust something with no proven benefit and a lot of potential risk? There are, it turns out, a swathe of entirely unregulated mixtures currently being sold in shops and online which clearly feature the substances I listed at the beginning. And more. Because they are all, supposedly, the starting materials in certain homeopathic remedies.

Homeopaths like to use unfamiliar, usually Latin-based, names which somewhat disguise the true nature of their ingredients. Here’s a short, but by no means comprehensive, list. (You might find remedies labelled differently but these are, as far as I can tell, the most common names given to these substances.)

If you haven’t heard of some of these, I do urge you to follow the links above, which will largely take you pages detailing their toxicology. Spoiler: the words “poison”, “deadly” and “fatal” feature heavily. These are nasty substances.

There are some big ironies here, and I’m not referring to the metal. For example, a common cry of anti-vaccinationists is that vaccines contain animal tissues – anything and everything from monkey DNA to dog livers. But many also seem to be keen to recommend homeopaths and courses of homeoprophylaxis – so-called “homeopathic vaccines” – which use bodily fluids such as pus and blood as starting materials.

Now, at this point I’m sure some of you are thinking, hang on a minute: aren’t you always telling us that “the dose makes the poison“? And aren’t homeopathic remedies diluted so much that none of the original substance remains, so they’re just placebos?

Yes, I am, and yes, they are.

Does anyone test homeopathic remedies to make sure there’s nothing in them….?

In THEORY. But here’s the problem: who’s testing these mixtures to make sure that the dilutions are done properly? And how exactly are they doing that (if they are)?

One technique that chemists use to identify tiny quantities of substance is gas chromatography (GC). This is essentially a high-tech version of that experiment you did at school, where you put some dots of different coloured ink on a piece of filter paper and watched them spread up the paper when you put it in some water.

GC analysis is brilliant at identifying tiny quantities of stuff. 10 parts per million is no problem for most detectors, and the most sensitive equipment can detect substances in the parts per billion range. Homeopathy dilutions are many orders of magnitude higher than this (30c, for example, means a dilution factor of 1060), but this doesn’t matter – once you get past 12c (a factor of 1024) you pass the Avogadro limit.

This is because Avogadro’s number, which describes the number of molecules in what chemists call a “mole” of a substance, is 6×1023. For example, if you had 18 ml of water in a glass, you’d have 6×1023 molecules of H2O. So you can see, if you’ve diluted a small sample by a factor of 1024 – more than the total number of molecules of water you had in the first place – the chances are very good that all you have is water. There will be none of the original substance left. (This, by the way, is of no concern to most homeopaths, who believe that larger dilutions magically produce a stronger healing effect.)

What if the sample ISN’T pure water after it’s been diluted?

If you carried out GC analysis of such a sample, you should find just pure water. Indeed, if you DIDN’T find pure water, it should be cause for concern. Potassium cyanide, for example, is toxic at very low levels. The lethal dose is is only 0.2-0.3 grams, and you’d suffer unpleasant symptoms long before you were exposed to that much.

So what if the dilutions somehow go wrong? What if some sample gets stuck in the bottle? Or on the pipette? Or a few dilution steps get skipped for some reason?

Are these largely unregulated companies rigorously quality-checking their remedies?

Well, maybe. It’s possible some producers are testing their raw materials for purity (ah yes, another question: they CLAIM they’re starting with, say, arsenic, but can we be certain?), and perhaps testing the “stability” of their products after certain periods of time (i.e. checking for bacterial growth), but are they running tests on the final product and checking that, well, there’s nothing in it?

And actually, isn’t this a bit of a conflict? If the water somehow “remembers” the chemical that was added and acquires some sort of “vibrational energy”, shouldn’t that show up somehow in GC analysis or other tests? If your tests prove it’s pure water, indistinguishable from any other sample of pure water, then… (at this point homeopaths will fall back on arguments such as “you can’t test homeopathy” and “it doesn’t work like that”. The name for this is special pleading.)

A warning was issued in the U.S. after several children became ill.

Am I scaremongering? Not really. There’s at least one published case study describing patients who suffered from arsenic poisoning after using homeopathic preparations. In January this year the U.S. Food and Drug Administration issued a warning about elevated levels of belladonna (aka deadly nightshade) in some homeopathic teething products. Yes, teething products. For babies. This warning was issued following several reports of children becoming ill after using the products. The FDA said that its “laboratory analysis found inconsistent amounts of belladonna, a toxic substance, in certain homeopathic teething tablets, sometimes far exceeding the amount claimed on the label.”

Now, admittedly, I’m based in the U.K. and these particular teething remedies were never readily available here. But let’s just type “homeopathy” into the Boots.com (the British high-street pharmacy) website and see what pops up… ah yes. Aconite Pillules, 30c, £6.25 for 84.

What happens if you search for “homeopathy” on the Boots.com website?

Have you been paying attention lovely readers? Aconite is…. yes! Monkshood! One of the most poisonous plants in the garden. Large doses cause instant death. Smaller doses cause nausea and diarrhea, followed by a burning and tingling sensation in the mouth and abdomen, possibly muscle weakness, low blood pressure and irregular heartbeat.

I must stress at this point that there is no suggestion, absolutely none whatsoever, that any of the products for sale at Boots.com has ever caused such symptoms. I’m sure the manufacturers check their preparations extremely carefully to ensure that there’s absolutely NO aconite left and that they really are just very small, very expensive, sugar pills.

Well, fairly sure.

In summary, we seem to be in a situation where people who proclaim that rigorously-tested and quality-controlled pharmaceuticals are “toxic” also seem to be happy to use unregulated homeopathic remedies made with ACTUALLY toxic starting materials.

I wonder if the new “documentary” about homeopathy, Just One Drop, which is being screened in London on the 6th of April will clarify this awkward little issue? Somehow, I doubt it. Having watched the trailer, I think it’s quite clear which way this particular piece of film is going to lean.

One last thing. Some homeopathic mixtures include large quantities of alcohol. For example, the Bach Original Flower Remedies are diluted with brandy and contain approximately 27% alcohol (in the interests of fairness, they do also make alcohol-free versions of some of their products and, as I’ve recently learned, they may not be technically homeopathic). Alcohol is a proven carcinogen. Yes, I know, lots of adults drink moderate quantities of alcohol regularly and are perfectly healthy, and the dose from a flower remedy is minuscule, but still, toxins and hypocrisy and all that.

There are cheaper ways to buy brandy than Bach Flower Remedies.

Amusingly, the alcohol in these remedies is described an “inactive” ingredient. It’s more likely to be the only ACTIVE ingredient. And since Flower Remedies retail for about £7 for 20 ml (a mighty £350 a litre, and they’re not even pure brandy) may I suggest that if you’re looking for that particular “medicine” you might more wisely spend your money on a decent bottle of Rémy Martin?

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Is acrylamide in your toast really going to give you cancer?

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Acrylamide has been in the news today, and this might be the understatement of the year. Front page newspaper headlines have been yelling everything from “Brits officially warned off chips” to “Over-cooked potatoes and burnt toast could cause cancer” to the marginally more restrained “What is the real cancer risk from eating roast potatoes or toast?” All this has been accompanied by radio interviews with everyone from actual scientists to professional chefs to people keen to share their roast potato recipes. I expect there have been television interviews too – I haven’t had a chance to watch.

Hey, what could be more traditional, or more fun, than a food-health scare in January?

Acrylamide

Acrylamide

Never fear, the Chronicle Flask is here to sort out the science. Let’s get to the facts: what is acrylamide?

It’s actually a rather small molecule, and it falls into a group of substances which chemists call amides. Other well-known amides include paracetamol and penicillin, and nylon is a polyamide – that is, lots of amide molecules joined together. Amide linkages (the CO-NH bit) are a key feature of proteins, which means they appear in all kinds of naturally-occurring substances.

And this is where the food-acrylamide link comes in. Because acrylamide, or prop-2-enamide to give it its official name (the one only ever used by A-level chemistry students), forms when certain foods are cooked.

Acrylamide occurs naturally in fried, baked, and roasted starchy foods.

Acrylamide occurs naturally in fried, baked, and roasted starchy foods.

It begins with an amino acid called asparagine. If you’re wondering whether, with that name, it has anything to do with asparagus, you’d be on the right track. It was first isolated in the early 1800s from asparagus juice. It turns out to be very common: it’s found in dairy, meat, fish and shellfish, as well as potatoes, nuts, seeds and grains, amongst other things.

This is where the trouble begins. When asparagine is combined with sugars, particularly glucose, and heated, acrylamide is produced. The longer the food is heated for, the more acrylamide forms. This is a particular issue with anything wheat or potato-based thanks to the naturally-occurring sugars those foods also contain – hence all the histrionics over chips, roast potatoes and toast.

How dangerous is acrylamide? The International Agency for Research on Cancer have classified it as a Group 2A carcinogen, or a “probable” carcinogen. This means there’s “limited evidence” of carcinogenicity in humans, but “sufficient evidence” of carcinogenicity in experimental animals. In other words (usually) scientists know the thing in question causes cancer in rats – who’ve generally been fed huge amounts under strictly controlled conditions – but there isn’t any clear evidence that the same link exists in humans. It’s generally considered unethical to lock humans in cages and force feed them acrylamide by the kilo, so it’s tricky to prove.

screen-shot-2017-01-23-at-22-10-46At this point I will point out that alcoholic beverages are classified as Group 1 carcinogens, which means there is “sufficient evidence” of carcinogenicity in humans. Alcohol definitely causes cancer. If you’re genuinely concerned about your cancer risk, worry less about the roast potatoes in your Sunday roast and more about the glass of wine you’re drinking with them.

But back to acrylamide. In animals, it has been shown to cause tumours. It’s one of those substances which can be absorbed through the skin, and after exposure it spreads around the body, turning up in the blood, unexposed skin, the kidneys, the liver and so on. It’s also been shown to have neurotoxic effects in humans. BUT, the evidence that it causes cancer in humans under normal conditions isn’t conclusive. A meta-analysis published in 2014 concluded that “dietary acrylamide is not related to the risk of most common cancers. A modest association for kidney cancer, and for endometrial and ovarian cancers in never smokers only, cannot be excluded.” 

The dose makes the poison is an important principle in toxicology (image credit: Lindsay Labahn)

The dose makes the poison (image credit: Lindsay Labahn)

As I so often find myself saying in pieces like this: the dose makes the poison. The people who have suffered neurotoxic effects from acrylamide have been factory workers. In one case in the 1960s a patient was handling 10% solutions of the stuff, and “acknowledged that the acrylamide solution frequently had splashed on his unprotected hands, forearms and face.” The earliest symptom was contact dermatitis, followed by fatigue, weight loss and nerve damage.

Because of these very real risks, the Occupational Safety and Health Administration and the National Institute for Occupational Safety and Health have set occupational exposure limits at 0.03 mg/m3 over an eight-hour workday, or 0.00003 g/m3.

Let’s contrast that to the amount of acrylamide found in cooked food. The reason all this fuss erupted today is that the Food Standards Agency (FSA) published some work which estimated the amounts of acrylamide people are likely to be exposed to in their everyday diet.

The highest concentrations of acrylamide were found in snacks (potato crisps etc), and they were 360 μg/kg, or 0.00036 g/kg or, since even the most ardent crisp addict doesn’t usually consume their favoured snacks by the kilo, 0.000036 g/100g. (Remember that those occupational limits are based on continuous exposure over an eight-hour period.)

In other words, the amounts in even the most acrylamide-y of foodstuffs are really quite tiny, and the evidence that acrylamide causes cancer in humans is very limited anyway. There is some evidence that acrylamide accumulates in the body, though, so consuming these sorts of foods day in and day out over a lifetime could be a concern. It might be wise to think twice about eating burnt toast every day for breakfast.

Oh yes, and there’s quite a lot of acrylamide in cigarette smoke. But somehow I doubt that if you’re a dedicated smoker this particular piece of information is going to make much difference.

As the FSA say at the end of their report:

Your toast almost certainly isn't going to kill you.

Your toast almost certainly isn’t going to kill you.

“The dietary acrylamide exposure levels for all age classes are of possible concern for an increased lifetime risk of cancer. The results of the survey do not increase concern with respect to acrylamide in the UK diet but do reinforce FSA advice to consumers and our efforts to support the food industry in reducing acrylamide levels.”

This is not, I would suggest, QUITE the same as “Crunchy toast could give you cancer, FSA warns” but, I suppose, “FSA says risk hasn’t really changed” wouldn’t sell as many newspapers.

One last thing, there’s acrylamide in coffee – it forms when the beans are roasted. There’s more in instant coffee and, perhaps counterintuitively, in lighter-roasted beans. No one seems to have mentioned that today, possibly because having your coffee taken away in January is just too terrifying a prospect to even contemplate. And also perhaps because coffee seems to be associated with more health benefits than negatives. Coffee drinkers are less likely to develop type 2 diabetes, Parkinson’s disease, dementia, suffer fewer cases of some cancers and fewer incidences of stroke. Whether the link is causal or not isn’t clear, but coffee drinking certainly doesn’t seem to be a particularly bad thing, which just goes to show that when it comes to diet, things are rarely clearcut.

Pass the crisps, someone.

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The Chronicles of the Chronicle Flask: 2016

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2016 is limping to its painful conclusion, still tossing out last-minute nasty surprises like upturned thumb tacks in the last few metres of a marathon. But the year hasn’t been ALL bad. Some fun, and certainly interesting, things happened too. No, really, they did, honestly.

So with that in mind, let’s have a look back at 2016 for the Chronicle Flask….

January kicked off with a particularly egregious news headline in a well-known broadsheet newspaper: Sugar found in ketchup and Coke linked to breast cancer. Turns out that the sugar in question was fructose. Yes, the sugar that’s in practically everything, and certainly everything that’s come from a plant. So why did the newspaper in question choose ketchup and Coke for their headline instead of, oh, say, fruit juice or honey? Surely not just in an effort to sell a few more newspapers after the overindulgent New Year celebrations. Surely.

octarineThere was something more lighthearted to follow when IUPAC  verified the discoveries of elements 113, 115, 117 and 118. This kicked off lots of speculation about the elements’ eventual names, and the Chronicle Flask suggested that one of them should be named Octarine in honour of the late Sir Terry Pratchett. Amazingly, this suggestion really caught everyone’s imagination. It was picked up in the national press, and the associated petition got over 51 thousand signatures!

In February I wrote a post about the science of statues, following the news that a statue to commemorate Sir Terry Pratchett and his work had been approved by Salisbury City Council. Did you know that there was science in statues? Well there is, lots. Fun fact: the God of metalworking was called Hephaestus, and the Greeks placed dwarf-like statues of him near their Hearths – could this be where the fantasy trope of dwarves as blacksmiths originates?

MCl and MI are common preservatives in cosmetic products

MCl and MI are common preservatives in cosmetic products

My skeptical side returned with a vengeance in March after I read some online reviews criticising a particular shampoo for containing a substance known as methylchloroisothiazolinone. So should you be scared of your shampoo? In short, no. Not unless you have a known allergy or particularly sensitive skin. Otherwise, feel free to the pick your shampoo based on the nicest bottle, the best smell, or the forlorn hope that it will actually thicken/straighten/brighten your hair as promised, even though they never, ever, ever do.

Nature Chemistry published Another Four Bricks in the Wall in April – a piece all about the potential names of new elements, partly written by yours truly. The month also brought a sinus infection. I made the most of this opportunity by writing about the cold cure that’s 5000 years old. See how I suffer for my lovely readers? You’re welcome.

In May I weighed in on all the nonsense out there about glyphosate (and, consequently, learned how to spell and pronounce glyphosate – turns out I’d been getting it wrong for ages). Is it dangerous? Nope, not really. The evidence suggests it’s pretty harmless and certainly a lot safer than most of its alternatives.

may-facebook-postSomething else happened in May: the Chronicle Flask’s Facebook page received this message in which one of my followers told me that my post on apricot kernels had deterred his mother from consuming them. This sort of thing makes it all worthwhile.

In June the names of the new elements were announced. Sadly, but not really very surprisingly, octarine was not among them. But element 118 was named oganesson and given the symbol Og. Now, officially, this was in recognition of the work of Professor Yuri Oganessian, but I for one couldn’t help but see a different reference. Mere coincidence? Surely not.

July brought another return to skepticism. This time, baby wipes, and in particular a brand that promise to be “chemical-free”. They’re not chemical-free. Nothing is chemical-free. This is a ridiculous label which shouldn’t be allowed (and yet, inexplicably, is still in use). It’s all made worse by the fact that Water Wipes contain a ‘natural preservative’ called grapefruit seed extract which, experiments have shown, only actually acts as a preservative when it’s contaminated with synthetic substances. Yep. Turns out some of Water Wipes claims are as stinky as the stuff they’re designed to clean up.

Maria Lenk Aquatic Enter, Tuesday, Aug. 9, 2016. (AP Photo/Matt Dunham)

Maria Lenk Aquatic Enter, Tuesday, Aug. 9, 2016. (AP Photo/Matt Dunham)

August brought the Olympics, and speculation was rife about what, exactly, was causing the swimming pools to turn such strange shades of green. Of course, the Chronicle Flask knew the correct solution…

August also saw MMS and CD reared their ugly heads on social media again. CD (chlorine dioxide) is, lest we forget, a type of bleach solution which certain individuals believe autistic children should be made to drink to ‘cure’ them. Worse, they believe such children should be forced to undergo daily enemas using CD solutions. I wrote a summary page on MMS (master mineral solution) and CD, as straight-up science companion to the commentary piece I wrote in 2015.

mugsSeptember took us back to pesticides, but this time with a more lighthearted feel. Did you know that 99.99% of all the pesticides you consume are naturally-occurring? Well, you do if you regularly read this blog. The Chronicle Flask, along with MugWow, also produced a lovely mug. It’s still for sale here, if you need a late Christmas present… (and if you use the code flask15 you’ll even get a discount!)

In October, fed up with endless arguments about the definition of the word ‘chemical’ I decided to settle the matter once and for all. Kind of. And following that theme I also wrote 8 Things Everyone Gets Wong About ‘Scary’ Chemicals for WhatCulture Science.

Just in case that wasn’t enough, I also wrote a chapter of a book on the missing science of superheroes in October. Hopefully we should see it in print in 2017.

Sparklers are most dangerous once they've gone out.

Sparklers are most dangerous once they’ve gone out.

I decided to mark Fireworks Night in November by writing about glow sticks and sparklers. Which is riskier? The question may not be as straightforward as you’d imagine. This was followed by another WhatCulture Science piece, featuring some genuinely frightening substances: 10 Chemicals You Really Should Be Scared Of.

And that brings us to December, and this little summary. I hope you’ve enjoyed the blog this year – do tell your friends about it! Remember to follow @ChronicleFlask on Twitter and like fb.com/chronicleflask on Facebook – both get updated more or less daily.

Here’s wishing all my lovely readers a very Happy New Year – enjoy a drop of bubbly ethanol solution and be careful with the Armstrong’s mixture…. 

See you on the other side!

new-year-1898553_960_720

10 Chemicals You Really SHOULD Be Scared Of

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Some chemicals really ARE scary...

Some chemicals really ARE scary…

People are increasingly worried about chemicals these days (even if they don’t quite know what the word means), but most of that fear is unfounded. The ingredients in cosmetics and foods are actually pretty harmless on the whole, certainly in the quantities you usually meet them.

This is because we’ve had decades of extensive testing and health and safety regulations – the truly nasty stuff simply isn’t allowed anymore. Even, sometimes, in fairly-obviously dangerous things like rat poison.

But the nasty stuff exists. Oh yes it does. You might be unlikely to come across it, but it’s still out there. Locked away. (Or not.)

So, come with me as I take you on a tour of 10 chemicals you really SHOULD be scared of…

Click to continue reading this article at WhatCulture Science

Glow sticks or sparklers: which is riskier?

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by Unknown artist,print,(circa 1605)

Remember, remember the 5th of November… (Image by Unknown artist, circa 1605)

It’s fireworks night in the UK – the day when we celebrate a small group of terrorists nearly managing to blow up the Houses of Parliament in 1605 by, er, setting fire to stuff. No, it makes perfect sense, honestly, because…. look, it’s fun, all right?

Anyway, logical or not, Brits light fireworks on this day to mark the occasion. Fireworks, of course, are dangerous things, and there’s been more than one petition to ban their sale to members of the general public because of safety concerns. It hasn’t happened yet, but public firework displays, rather than private ones at home, are more and more popular.

Which brings me to this snippet from a letter a friend of mine recently received.

screen-shot-2016-11-04-at-21-51-33

In case you can’t read it, it says:

“NO SPARKLERS PLEASE – with so many children runni[ng] around, we believe it is too dangerous fro children to be [words missing] lighted sparklers around.
Last year we had a few incidents of children drinking the [words missing] glowsticks – please advise against this.”

Now there are some words missing here, but it’s fairly clear that sparklers are prohibited at this event, and it seems to be suggesting that children have managed to get into, and swallow, the contents of glowsticks. But they, by contrast, haven’t been banned. Indeed, parents are merely being asked to “advise” against it.

Hmmm.

Does this seem like an appropriate response? Well, let’s see…

1024px-sparklers_moving_slow_shutter_speedWhat are these things? Let’s begin with sparklers. They’re hand-held fireworks, usually made of a stiff metal wire, about 20 cm long, the end of which is dipped in a thick mixture of metallic particles, fuel and an oxidising agent. The metal particles are most commonly magnesium and/or iron. The fuel usually involves charcoal, and the oxidiser is likely to be potassium nitrate. Sometimes metal salts are also added to produce pretty colours.

Sparklers are designed to burn hot and fast. The chemical-dipped end can reach temperatures between 1000-1600 oC, but the bit you hold doesn’t have time to heat up before the firework goes out (although gloves are still recommended). The sparks, likewise, are extremely hot but burn out in seconds. This makes sparklers relatively safe, if they’re held well way from the face and body, and if the hot end isn’t touched.

If. Every year there are injuries. Sparkler injuries aren’t recorded separately from other firework injuries in the UK, but the data we do have suggest we might be looking at a few thousand A&E admissions each year, and probably a lot more minor injuries which are treated at home.

Sparklers are most dangerous once they've gone out.

Sparklers are most dangerous after they’ve gone out.

The biggest danger comes from people, usually children, picking up ‘spent’ sparklers. The burny end takes a long time to cool down, but once the sparkles are finished and it’s stopped glowing it’s impossible to judge how hot it is just by looking.

The burns caused by picking up hot sparklers are undoubtedly very, very nasty, but they’re also relatively easy to avoid. Supply buckets of cold water, and drill everyone to put their spent sparklers into the buckets as soon as they go out. Hazard minimised. Well, assuming everyone follows instructions of course, which isn’t always a given. Other risks are people getting poked with hot sparkers – which can be avoided by insisting sparkler-users stand in a line, facing the same way, with plenty of space in front of them – and people lighting several sparklers at once and getting a flare. Again, fairly easily avoided in a public setting, where you can threaten and nag everyone about safety and keep an eye on what they’re doing.

Although I do understand the instinct to simply ban the potentially-dangerous thing, and thus remove the risk, the idea does worry me a little bit. I was born in the 70s and I grew up with fire. I remember the coal truck delivering coal to us and our neighbours. I was taught how to light a match at an early age, and cautioned not to play with them (and then I did, obviously, because in those days it was usual for kids to spend hours and hours entirely unsupervised – but fortunately I emerged unscathed). Pretty much everyone kept a supply of candles in a drawer, in case the lights went out. And bonfires were a semi-regular event – this being long before garden waste collections.

These days things are very different. It’s not unusual to meet a child who, by age 11, has never lit a match. If their home oven and hob are electric, they may never have seen a flame outside of yearly birthday cake candles. But so what? You may be thinking. Aren’t fewer burns and house fires a good thing?

Of course they are, but people who’ve never dealt with fire tend to panic when faced with it. If the only flame you’ve ever met is a birthday cake candle, your instinct might well be to blow when faced with something bigger. This can be disastrous – it can make the fire worse, and it can spread hot embers to other nearby flammable items.

I’m personally of the opinion that children ought to be taught to handle fire safely, how to safely extinguish a small fire, when to call in the experts, and not to disintegrate into hysterics the presence of anything warmer than a cup of tea. Sparklers, I think, can be part of that. Particularly if they’re used in a well-supervised setting, with plenty of safety measures and guidance on-hand. (As opposed to, say, picking them up for the first time at university with some drunk mates, setting fire to half a dozen at once and immediately dropping them.)

Now. Onto glowsticks. They’re pretty neat, aren’t they? We’ve already established that I’m quite old, and I remember these appearing in shops for the first time, sometime in the very early 90s, and being utterly mesmerised by that eerie, cold light.

phenyl_oxalate_ester

Diphenyl oxalate (trademark name Cyalume)

They work thanks to two chemicals. Usually, these are hydrogen peroxide (H2O2 – also used to bleach hair, as a general disinfectant, and as the subject of a well-known punny joke involving two scientists in a bar) and another solution containing a phenyl oxalate ester and a fluorescent dye.

These two solutions are separated, with the hydrogen peroxide in a thin-walled, sealed glass vial which is floating in the mixture of ester and dye solution. The whole thing is then sealed in a tough, plastic coating. When you bend the glowstick the glass breaks, the chemicals mix, and a series of chemical reactions happen which ultimately produce light.

How Light Sticks work (from HowStuffWorks.com - click image for more)

How Light Sticks work (from HowStuffWorks.com – click image for more)

Which is all very well. Certainly nice and safe, you’d think. Glowsticks don’t get hot. The chemicals are all sealed in a tube. What could go wrong?

I thought that too, once. Until I gave some glowsticks to some teenagers and they, being teenagers, immediately ripped them apart. You see, it’s actually not that difficult to break the outer plastic coating, particularly on those thin glow sticks that are often used to make bracelets and necklaces. Scissors will do it easily, and teeth will also work, with a bit of determination.

How dangerous is that? Well… it’s almost impossible to get into a glowstick without activating it (the glass vial will break), so it’s less the reactants we need to worry about, more the products.

And those are? Firstly, carbon dioxide, which is no big deal. We breathe that in and out all the time. Then there’s some activated fluorescent dye. Now, these vary by colour and by manufacturer, but as a general rule they’re not something anyone should be drinking. Some fluorescent dyes are known to cause adverse reactions such as nausea and vomiting, and if someone turns out to be allergic to the dye the consequences could be serious. This is fairly unlikely, but still.

Another product of the chemical reactions is phenol, which is potentially very nasty stuff, and definitely not something anyone should be getting on their skin if they can avoid it, let alone drinking.

Inside every activated glowstick are fragments of broken glass.

Inside every activated glowstick are fragments of broken glass.

And then, of course, let’s not forget the broken glass. Inside every activated glowstick are fragments of broken glass – it’s how they’re designed to work. If you break the plastic coating, that glass is exposed. If someone drinks the solution inside a glow stick they could, potentially, swallow that glass. Do I need to spell out the fact that this would be a Bad Thing™?

The thing with hazards is that, sometimes, something that’s obviously risky actually ends up being pretty safe. Because people take care over it. They put safety precautions in place. They write risk assessments. They think.

Whereas something that everyone assumes is safe can actually be more dangerous, precisely because no one thinks about it. How many people know that glowsticks contain broken glass, for instance? Probably not the writer of that letter back there, else they might have used stronger language than “please advise against this.”

So glowsticks or sparklers? Personally, I’d have both. Light on a dark night, after all, is endlessly fascinating. But I’d make sure the sparkler users had buckets of water, cordons and someone to supervise. And glowstick users also ought to be supervised (at least by their parents), warned in the strongest terms not to attempt to break the plastic, and all efforts should be made to ensure that the pretty glowy things don’t fall into the hands of a child still young enough to immediately stuff everything into his or her mouth.

The most important thing about managing risks is not to eliminate every potentially hazardous thing, but rather to understand and plan for the dangers.

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