Tag Archives: toxic

Neem: nice, nasty or… not sure?

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A few days ago it was sunny and slightly breezy outside (yes, it’s August, but I live in the UK – this isn’t as common as you might imagine) and I thought, I should make the most of this and do something about my orchids.

Now, anyone that reads this blog regularly will know that my Dad is a horticulturist. I, however, am not. My fascination with bright colours, interesting smells and complicated naming conventions went down the chemistry route. But I am, oddly, quite good with Phalaenopsis, aka, moth orchids. I don’t really know why, or how, but I seem to have come to some sort of agreement with the ones that live on my kitchen windowsill. It goes along the lines of: I’ll water you once a week, and you make flowers a couple of times a year, and we’ll otherwise leave each other alone, okay?

Scale bugs secrete honeydew, which encourages the growth of sooty moulds

Well, this was fine for years, until we somehow acquired an infestation of scale bugs. These tiny but extremely annoying pests feed by sucking sap from leaves of plants, and they excrete a sticky substance called honeydew. Trust me, it’s not as nice as it sounds. Firstly, it really is sticky, and makes a horrible mess not just of the orchid leaves, but also the area around the plants.

Then it turns out that certain types of mould just love this stuff, so you end up with black spots on the leaves. And, not surprisingly, all this weakens the plant.

So, what’s the answer? Well, there are several. But the one I tend to default to is neem oil.

This stuff is a vegetable oil from the seeds of the Azadirachta indica, or neem, tree. It has a musty, nutty sort of smell, and is fairly easy to buy.

It’s indigenous to the Indian subcontinent and has been historically important in traditional medicine. In fact, The Sanskrit name of this evergreen tree is ‘Arishtha’, which means ‘reliever of sickness’.

So it’s a natural vegetable oil and people have been using it as a remedy for thousands of years – must be totally safe, right? Right?

Well… I’ve said it before, but some of the very best horribly toxic things are entirely natural, and neem is yet another example. Ingestion of significant quantities can cause metabolic acidosis (finally, something that really does have the potential to change blood pH! Er… but not… in a good way), kidney failure, seizures, and brain damage in children. Skin contact can cause contact dermatitis. It’s been shown to work as a contraceptive and, more problematically, it’s a known abortifacient (causes miscarriage).

Neem oil is easy to buy, but it needs to be handled with caution

All this said, as always, the dose make the poison.

One case study in the Journal of The Association of Physicians of India reported on a 36-year-old man who swallowed 30–50 ml (about three tablespoons) of neem oil, in the hope of treating the corns on his feet. As far as I can tell, it didn’t help his corns. It did cause vomiting, drowsiness, a dangerous drop in blood pH and seizures. There’s no specific antidote for neem poisoning, but the hospital managed his symptoms. Luckily, despite the hammering his kidneys undoubtedly took, he didn’t need dialysis, and was discharged from hospital after just over a week.

Now, okay, you’re unlikely to accidentally swallow three tablespoons of any oil, especially not neem which does have quite a strong, not entirely pleasant, smell and (reportedly – I haven’t tried for obvious reasons) a bitter taste. But nevertheless, it’s wise to be cautious, particularly around children who have a smaller body mass and therefore are much more likely to suffer serious effects – up to and including death. In one reported case, a mother gave a 3-month-old child a teaspoon of neem oil in the hope of curing his indigestion – fortunately he survived, but not without some seriously scary symptoms.

Nimbin, a chemical found in neem oil, is reported to have all sorts of beneficial effects [image source]

Okay, so those are the dangers. Let’s talk chemistry. The Pakistani organic chemist Salimuzzaman Siddiqui is thought to be the first scientist to formally investigate the various compounds in neem oil. In 1942 he extracted three compounds, and identified nimbidin as the main antibacterial substance in neem. He was awarded an OBE in 1946 for his discoveries.

I will confess, at this point, to running into a little bit of confusion with the nomenclature. Nimbidin is described, in some places at least, as a mixture of compounds (collectively, tetranortriterpenes) rather than a single molecule. But either way, it has been shown to have anti-inflammatory properties – at least in rats.

Another of the probably-mostly-good substances in neem is nimbin: a triterpenoid which is reported to have a whole range of positive properties, including acting as an anti-inflammatory, an antipyretic, a fungicide, an antiseptic and even as an antihistamine. Interestingly, I went looking for safety data on nimbin, and I couldn’t find much. That could mean it’s safe, or it could mean it just hasn’t been extensively tested.

Azadirachtin, another chemical found in neem, is a known pesticide [image source]

The substance that seems to do most of the pesticide heavy lifting is azadirachtin. This is a limonoid (compounds that are probably best known for their presence in citrus fruits). It’s what’s called an antifeedant – a substance produced by plants to deter predators from munching on them. Well, mostly. Humans have a strange habit of developing a taste for plants that produce such substances. Take, for example, odoriferous garlic, clears-out-your-sinuses horseradish, and of course the daddy of them all: nicotine.

Azadirachtin is known to affect lots of species of insects, both by acting as an antifeedant and as a growth disruptor. Handily, it’s also biodegradable – and breaks down in a few days when exposed to light and water.

That makes it appealing as a potential pesticide, and it’s also generally described as having low toxicity in mammals – its reported LD50 tends to fall into the grams per kilogram range, which makes it “moderately to slightly toxic“. Wikipedia quotes a value (without a source, as I write this) of >3,540 mg/kg in rats.

But… I did find another page quoting 13 mg/kg in mice. That’s quite dramatically different, and would make it extremely/highly toxic. Unfortunately I couldn’t get my hands on the original source, so I haven’t been able to verify it’s not a transposition error.

Let’s assume it isn’t. It would be odd to have such a big difference between mice and rats. Things that poison mice tend to poison rats, too. There might be some confusion over pure azadirachtin vs. “neem extract” – it could be the case that the mixture of chemicals working together in neem create some sort of synergistic (toxic) effect – greater than the sum of all the individual substances. It could be an experimental error, including a contaminated neem sample, or something to do with the way the animals were exposed to the extract.

Neem soap is widely available online, but that may not be a good thing…

It’s difficult to say. Well, it’s difficult for me to say, because I don’t have access to all the primary sources. (Any toxicologists out there, please do feel free to weigh into the comments section!) But either way, as I’ve already mentioned, several case studies have fingered azadirachtin as one of the substances likely to be causing the well-reported nasty side effects.

If you’re asking this chemist? I say be careful with the stuff. If you decide to use it on your plants, keep it out of reach of children, and wear some good-quality disposable gloves while you’re handling it (I put some on after I took that photo back there). If you’re pregnant, or trying to become pregnant, the safest option is to not use it at all.

Which brings me to neem soap.

Yup. It’s sold as a “natural” treatment for skin conditions like acne. I won’t link to a specific brand, but it’s easy to find multiple retailers with a simple Google search. I looked at one selling soap bars for £6.99 a pop, containing 10% (certified organic, because of course) neem oil. Did I mention back there that neem is known to cause contact dermatitis? I’m fairly sure I did. None of the products I saw had obvious safety warnings, and I certainly found nothing about safety (or otherwise) for pregnant women.

Plus – worryingly, not least because children are more likely to get things in their mouth – you can also buy kids and babies versions, again purporting to contain 10% neem oil.

I even found neem toothpaste. Which… given people often swallow toothpaste… yikes.

My moth orchids are looking much healthier now I’ve got rid of all the scale bugs!

Now again, and for the umpteenth time, the dose makes the poison. The case studies I’ve mentioned involved, at a minimum, swallowing a teaspoon of pure neem oil, and you’re not getting that sort of quantity from smears of toothpaste. But, at the same time, when it comes to pregnancy and babies, it’s generally sensible to apply a precautionary principle, especially for things like soap and toothpaste for which alternatives with well-established safety profiles exist.

Bottom line? Would I use these products? I would not.

But I do use neem to treat the scale bugs on my orchids, and they’re doing much better than they were. Fingers crossed for more flowers!

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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!

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No need for slime panic: it’s not going to poison anyone

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This is one of my favourite photos, so I’m using it again.

The school summer holidays are fast approaching and, for some reason, this always seems to get people talking about slime. Whether it’s because it’s a fun end-of-term activity, or it’s an easy bit of science for kids to do at home, or a bit of both, the summer months seem to love slimy stories. In fact, I wrote a piece about it myself in August 2017.

Which (hoho) brings me to the consumer group Which? because, on 17th July this year, they posted an article with the headline: “Children’s toy slime on sale with up to four times EU safety limit of potentially unsafe chemical” and the sub-heading: “Eight out of 11 popular children’s slimes we tested failed safety testing.”

The article is illustrated with lots of pots of colourful commercial slime pots with equally colourful names like Jupiter Juice. It says that, “exposure to excessive levels of boron could cause irritation, diarrhoea, vomiting and cramps in the short term,” and goes on to talk about possible risks of birth defects and developmental delays. Yikes. Apparently the retailer Amazon has removed several slime toys from sale since Which? got on the case.

The piece was, as you might expect, picked up by practically every news outlet there is, and within hours the internet was full of headlines warning of the dire consequences of handling multicoloured gloopy stuff.

Before I go any further, here’s a quick reminder: most slime is made by taking polyvinyl alcohol (PVA – the white glue stuff) and adding a borax solution, aka sodium tetraborate, which contains the element boron. The sodium tetraborate forms cross-links between the PVA polymer chains, and as a result you get viscous, slimy slime in place of runny, gluey stuff. Check out this lovely graphic created by @compoundchem for c&en’s Periodic Graphics:

The Chemistry of Slime from cen.acs.org (click image for link), created by Andy Brunning of @compoundchem

And so, back to the Which? article. Is the alarm justified? Should you ban your child from ever going near slime ever again?

Nah. Followers will remember that back in August last year, after I posted my own slime piece, I had a chat with boron-specialist David Schubert. He said at the time: “Borax has been repeated[ly] shown to be safe for skin contact. Absorption through intact skin is lower than the B consumed in a healthy diet” (B is the chemical symbol for the element boron). And then he directed me to a research paper backing up his comments.

Borax is a fine white powder, Mixed with water it can be used to make slime.

This, by the way, is all referring to the chemical borax – which you might use if you’re making slime. In pre-made slime the borax has chemically bonded with the PVA, and that very probably makes it even safer – because it’s then even more difficult for any boron to be absorbed through skin.

Of course, and this really falls under the category of “things no one should have to say,” don’t eat slime. Don’t let your kids eat slime. Although even if they did, the risks are really small. As David said when we asked this time: “Borates have low acute toxicity. Consumption of the amount of borax present in a handful of slime would make one sick to their stomach and possibly cause vomiting, but no other harm would result. The only way [they] could harm themselves is by eating that amount daily.”

It is true that borax comes with a “reproductive hazard” warning label. Which? pointed out in their article that there is EU guidance on safe boron levels, and the permitted level in children’s’ toys has been set at 300 mg/kg for liquids and sticky substances (Edited 18th July, see * in Notes section below).

EU safety limits are always very cautious – an additional factor of at least 100 is usually incorporated. In other words, for example, if 1 g/kg exposure of a substance is considered safe, the EU limit is likely to be set at 0.01 g/kg – so as to make sure that even someone who’s really going to town with a thing would be unlikely to suffer negative consequences as a result.

The boron limit is particularly cautious and is based on animal studies (and it has been challenged). The chemists I spoke to told me it’s not representative of the actual hazards. Boron chemist Beth Bosley pointed out that while it is true that boric acid exposure has been shown to cause fetal abnormalities when it’s fed to pregnant rats, this finding hasn’t been reproduced in humans. Workers handling large quantities of borate in China and Turkey have been studied and no reproductive effects have been seen.

Rat studies, she said, aren’t wholly comparable because rats are unable to vomit, which is significant because it means a rat can be fed a large quantity of a boron-containing substance and it’ll stay in their system. Whereas a human who accidentally ingested a similar dose would almost certainly throw up. Plus, again, this is all based on consuming substances such as borax, not slime where the boron is tied up in polymer chains. There really is no way anyone could conceivably eat enough slime to absorb these sorts of amounts†.

These arguments aside, we all let our children handle things that might be harmful if they ate them. Swallowing a whole tube of toothpaste would probably give your child an upset stomach, and it could even be dangerous if they did it on a regular basis, but we haven’t banned toothpaste “just in case”. We keep it out of reach when they’re not supposed to be brushing their teeth, and we teach them not to do silly things like eating an entire tube of Oral-B. Same basic principle applies to slime, even if it does turn out to contain more boron than the EU guidelines permit.

In conclusion: pots of pre-made slime are safe, certainly from a borax/boron point of view‡, so long as you don’t eat them. The tiny amounts of boron that might be absorbed through skin are smaller than the amounts you’d get from eating nuts and pulses, and not at all hazardous.

Making slime at home can also be safe, if you follow some sensible guidelines like, say, these ones:

Stay safe with slime by following this guidance

Slime on, my chemistry-loving friends!

Notes:
* When I looked for boron safety limits the first time, the only number I could find was the rather higher 1200 mg/kg. So I asked Twitter if anyone could direct me to the value Which? were using. I was sent a couple of links, one of which contained a lot of technical documentation, but I think the most useful is probably a “guide to international toy safety” pamphlet which includes a “Soluble Element Migration Requirements” table. In the row for boron, under “Category II: Liquid or sticky materials”, the value is indeed given as 300 mg/kg.

BUT, there is also ” Category I: Dry, brittle, powder like or pliable materials” and the value there is the much higher 1,200 mg/kg. Which begs the question: does slime count as “pliable” or “sticky”? It suggests to me that, say, a modelling clay product (pliable) would have the 4x higher limit. But surely the risk of exposure would be essentially the same? If 1,200 mg/kg is okay for modelling clay, I can’t see why it shouldn’t be for slime. In the Which? testing, only the Jupiter Juice product exceeded the Category I limit, and then not by that much (1,400 mg/kg).

Also (the notes are going to end up being longer than the post if I’m not careful), these values are migration limits, not limits on the amount allowed in the substance in total. Can anyone show that more than 300 mg/kg is able to migrate from the slime to the person handling it? Very unlikey. But again, don’t eat slime.

† This is not an invitation to try and prove me wrong.

‡ I suppose it’s possible that someone could sell slime that’s contaminated with some other toxic thing. But that could happen with anything. The general advice to “wash your/their hands and don’t eat it” will take you a long way.

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Toxins and tanks: could your fishtank really be deadly?

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Could a deadly poison be lurking in your fish tank?

A few days ago I came across a news story: “Fish owner tells how cleaning out tank released deadly palytoxin that poisoned family and led to closure of entire street“. Now you have to admit, as titles go that’s pretty compelling.

To begin with, for some reason, I had it in my head that this happened in Australia (in my defence, that is where most of the really deadly stuff happens, right?). But no, this happened in the U.K. Not only that, but it was even in Oxfordshire, which is my neck of the woods.

The fish tank owner, a man named Chris Matthews, was actually an experienced aquarist. He knew about palytoxin – a poisonous substance which can be released by corals – and he was aware that it can be deadly if ingested. He also knew that it can cause serious skin irritation.

What he didn’t realise was that taking his pulsing xenia coral out of the tank could cause it to release the toxin into the air.

But before I talk about palytoxin, let’s just look at the word “toxin” for a moment. It has a specific meaning, and it’s often misused. As in many, many adverts. Here’s a recent one, but these easy to find – just put “toxin free” into the search engine of your choice.

In a way, this is quite funny. You see, “toxin” specifically refers to “a poison of plant or animal origin“. In other words, a naturally occurring poison*. There are lots and lots of naturally occurring poisons. Plants make them all the time, generally to ward off pests. Most essential oils can, at a high enough dose, be toxic. The hand cream in that picture contains peppermint oil. Peppermint is, of course, pretty safe – we’ve all eaten mints after all – but guess what? Take huge dose of it and it becomes a real problem. Now, I’m not for one second suggesting that hand cream is dangerous or harmful, but technically, it’s not “toxin free”.

Beauty products which contain only synthetic ingredients are, by definition, toxin-free.

Yes, the irony or this sort of marketing is that beauty products made out of entirely synthetic ingredients definitely will be toxin-free. Nothing natural = no toxins. Whereas anything made out of naturally occurring substances almost certainly isn’t, regardless of its spurious labelling.

Anyway, back to the palytoxin. It’s naturally occurring. And incredibly dangerous. More proof, as if we needed it, that natural doesn’t mean safe. Very often, in fact, quite the opposite. The human race has spent millenia working out how to protect itself from nature and all her associated nastiness (bacteria, viruses, extreme temperatures, poor food supply, predators…. the list is long and unpleasant) and yet for some reason it’s become fashionable to forget all that and imagine a utopia where mother nature knows best. Honestly, she doesn’t. Well, maybe she does – but being kind to human beings isn’t on her agenda.

Palytoxin is especially unpleasant. Indeed, it’s thought to be the second most poisonous non-protein substance known (there are some very impressive protein-based ones, though – botulinum toxin for one). The only thing which is more toxic is maitoxin – a poison which can be found in striated surgeonfish thanks to the algae they eat.

Palytoxin is a large molecule.

Palytoxin is a big molecule, technically categorised as a fatty alcohol. It has eight carbon-carbon double bonds, 40 hydroxy groups (phew) and is positively covered in chiral centres (don’t worry students: your teacher isn’t going to expect you to draw this one. Probably). Bits of it are water-soluble whilst other parts are fat soluble, meaning it can dissolve in both types of substance. Because it’s not a protein, heat doesn’t denature it, so you can’t get rid of this toxin with boiling water or by heating it. However, it does decompose and become non-toxic in acidic or alkaline solutions. Household bleach will destroy it.

It’s mostly found in the tropics, where it’s made by certain types of coral and plankton, or possibly by bacteria living on and in these organisms. It also turns up in fish, crabs and other marine organisms that feed on these things.

In fact, story time! There is a Hawaiian legend which tells that Maui villagers once caught a Shark God with a hunger for human flesh whom they believed had been killing their fishermen. They killed the Shark God and burned him, throwing the ashes into a tide pool. The ashes caused ugly brown anemones to grow. Later, the villagers discovered that blades smeared with these “limu” would cause certain death. So the anemones came to be known as “Limu Make O Hana” or Seaweed of Death from Hana. We now know that those brown ‘anemones’ are zoanthid corals, and the ‘certain death’ was due to palytoxin poisoning.

Zoanthids are a source of palytoxin.

People don’t suffer palytoxin poisoning very often. Most cases have been in people who’ve eaten seafood and, as here, aquarium hobbyists. In a few cases people have been exposed to algae blooms.

It’s really nasty though. Palytoxin can affect every type of cell in the body (yikes) and as a result the symptoms are different according to the route of exposure. Eat it and you’re likely to experience a bitter taste in your mouth, muscle spasms and abdominal cramps, nausea, lethargy, tingling and loss of sensation, slow heart rate, kidney failure and respiratory distress. It can damage your heart muscle; in the worst case scenario, it causes death by cardiac arrest.

On the other hand, if you inhale it, the symptoms are more likely to revolve around the respiratory system, such as constriction of the airways which causes wheezing and difficulty breathing. It can also cause fever and eye-infection type symptoms. Over time, though, the result is the same: muscle weakness and eventually, death from heart failure.

The respiratory symptoms from palytoxin are easily misdiagnosed: it looks like a viral or bacterial infection. In fact, our fish tank owner initially thought he had flu. It was only when everyone in the family got ill, even the dogs, that he realised that it must be poisoning. Fortunately, the emergency services took it seriously and sent both ambulance and fire crews to his house, as well as police. They closed the street and ensured that the poison was safely removed.

There is no antidote, but the symptoms can be eased by, for example, treatment with vasodilators. If the source of exposure is removed the victim is likely to recover over time. You’ll be pleased to hear that Chris Matthews, his family, and the firefighters who attended the scene, were checked over at hospital and appear to be okay.

If you’re an aquarium owner, how to you avoid getting into this kind of predicament? As Chris Matthews said, the coral he had, pulsing xenia, was “not expensive and a lot of people have it.”

Click the image to read safety guidelines from the Ornamental Aquatic Trade Association.

According to the Ornamental Aquatic Trade Association, the most important piece of safety advice is to only handle your marine creatures underwater and fully submerged. Don’t take them out of the tank unnecessarily, and if you do need to move them, use submerged plastic bags or a bucket, so that they stay underwater at all times. You should also wear strong rubber gloves, ideally gloves specifically designed for aquarium use (such as these). If you need to dispose of a rock which contains soft coral species, soak it in a bleach solution – one part household bleach to nine parts water – for several days before you intend to dispose of it. Leaving an untreated rock outside to dry will not make it safe – it could still be highly toxic. Finally, whilst activated charcoal can help to keep palytoxin out of the water, it may not be able to cope with large quantities, and it needs to be changed frequently.

Fish tank owner Chris also said: “The information is not readily available online in a way people can easily understand” and “I want to use this experience to educate people about the risks and the measures people need to take.” Hopefully this blog post (and all the associated news coverage) will help with that. Be careful with your corals!

* Note that while ‘toxin’ specifically refers to poisonous substances from plants and animals, this restriction doesn’t extend to the word “toxic”. The definition of that is “containing or being poisonous material” (regardless of whether it’s a naturally-occurring substance or not). So “non-toxic” labels are fine, if a little bit meaningless – no matter what the woo-pushing sites say, your hand cream really isn’t poisonous.

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Chemical du jour: how bad is BPA, really?

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BPA is an additive in many plastics

When I was writing my summary of 2017 I said that there would, very probably, be some sort of food health scare at the start of 2018. It’s the natural order of things: first we eat and drink the calorie requirement of a small blue whale over Christmas and New Year, and then, lo, we must be made to suffer the guilt in January. By Easter, of course, it’s all forgotten and we can cheerfully stuff ourselves with chocolate eggs.

Last year it was crispy potatoes, and the year before that it was something ridiculous about sugar in ketchup causing cancer (it’s the same sugar that’s in everything, why ketchup? Why?). This year, though, it seems that the nasty chemical of the day is not something that’s in our food so much as around it.

Because this year the villain of the piece appears to be BPA, otherwise known as Bisphenol A or, to give it its IUPAC name, 4,4′-(propane-2,2-diyl)diphenol.

BPA is an additive in plastics. At the end of last year an excellent documentary aired on the BBC called Blue Planet II, all about our planet’s oceans. It featured amazing, jaw-dropping footage of wildlife. It also featured some extremely shocking images of plastic waste, and the harm it causes.

Plastic waste is a serious problem

Plastic waste, particularly plastic waste which is improperly disposed of and consequently ends up in the wrong place, is indisputably something that needs to be addressed. But this highlighting of the plastic waste problem had an unintended consequence: where was the story going to go? Everyone is writing about how plastic is bad, went (I imagine) editorial meetings in offices around the country – find me a story showing that plastic is even WORSE than we thought!

Really, it was inevitable that a ‘not only is plastic bad for the environment, but it’s bad for you, too!’ theme was going to emerge. It started, sort of, with a headline in The Sun newspaper: “Shopping receipts could ‘increase your cancer risk’ – as 93% contain dangerous chemicals also linked to infertility. Shopping receipts are, of course, not made of plastic – but the article’s sub-heading stated that “BPA is used to make plastics”, so the implication was clear enough.

Then the rather confusing: “Plastic chemical linked to male infertility in majority of teenagers, study suggests” appeared in The Telegraph (more on this in a bit), and the whole thing exploded. Search for BPA in Google News now and there is everything from “5 Ways to Reduce Your Exposure to Toxic BPA” to “gender-bending chemicals found in plastic and linked to breast and prostate cancer are found in 86% of teenagers”.

Yikes. It’s all quite scary. It’s true that right now you can’t really avoid plastic. Look around you and it’s likely that you’ll immediately see lots of plastic objects, and that’s before you even try to consider all the everyday things which have plastic coatings that aren’t immediately obvious. If you have young children, you’re probably drowning in plastic toys, cups, plates and bottles. We’re pretty much touching plastic continually throughout our day. How concerned should we be?

As the Hitchiker’s Guide to the Galaxy says, Don’t Panic. Plastic (like planet Earth in the Guide) can probably be summed up as mostly harmless, at least from a BPA point of view if not an environmental one.

BPA is a rather pleasingly symmetrical molecule with two phenol groups. (A big model of this would make a wonderfully ironic pair of sunglasses, wouldn’t it?) It was first synthesized by the Russian chemist Alexander Dianin in the late 19th century. It’s made by reacting acetone – which is where the “A” in the name comes from – with two phenol molecules. It’s actually a very simple reaction, although the product does need to be carefully purified, since large amounts of phenol are used to ensure a good yield.

It’s been used commercially since the fifties, and millions of tonnes of BPA are now produced worldwide each year. BPA is used to make plastics which are clear and tough – two characteristics which are often valued, especially for things like waterproof coatings, bottles and food containers.

The concern is that BPA is an endocrine disruptor, meaning that it interferes with hormone systems. In particular, it’s a known xenoestrogen, in other words it mimics the female hormone estrogen. Animal studies have suggested possible links to certain cancers, infertility, neurological problems and other diseases. A lot of the work is fairly small-scale and, as I’ve mentioned, focused on animal studies (rather than looking directly at effects in humans). Where humans have been studied it’s usually been populations that are exposed to especially high BPA levels (epoxy resin painters, for example). Still, it builds up into quite a damning picture.

BPA has been banned from baby bottles in many countries, including the USA and Europe

Of course, we don’t normally eat plastic, but BPA can leach from the plastic into the food or drink that’s in the plastic, and much more so if the plastic is heated. Because of these concerns, BPA has been banned from baby bottles (which tend to be heated, both for sterilisation and to warm the milk) in several countries, including the whole of Europe, for some years now. “BPA free” labels are a fairly common sight on baby products these days. BPA might also get onto our skin from, for example, those thermal paper receipts The Sun article mentioned, and then into our mouths when we eat. Our bodies break down and excrete the chemical fairly quickly, in as little as 6 hours, but because it’s so common in our environment most of us are continually meeting new sources of it.

How much are we getting, though? This is a critical question, because as I’m forever saying, the dose makes the poison. Arsenic is a deadly poison at high levels, but most of us – were we to undergo some sort of very sensitive test – would probably find we have traces of it in our systems, because it’s a naturally-occuring mineral. It’s nothing to worry about, unless for some reason the levels become too high.

When it comes to BPA, different countries have different guidelines. The European Food Safety Authority recommended in January 2015 that the TDI (tolerable daily intake) should be reduced from 50 to 4 µg/kg body weight/day (there are plans for a new assessment in 2018, so it might change again). For a 75 kg adult, that translates to about 0.0003 g per day. A USA Federal Drug and Administration document from 2014 suggests a NOAEL (no-observed-adverse-effect-level) of 5 mg/kg bw/day, which translates to 0.375 g per day for the same 75 kg adult. NOAEL values are usually much higher than TDIs, so these two figures aren’t as incompatible as they might appear. Tolerable daily intake values tend to have a lot of additional “just in case” tossed into them – being rather more guidance than science.

The European Food Standards Authority published a detailed review of the evidence in 2015 (click for a summary)

So, how much BPA are we exposed to? I’m going to stick to Europe, because that’s where I’m based (for now…), and trying to look at all the different countries is horribly complicated. Besides, EFSA produced a really helpful executive summary of their findings in 2015, which makes it much easier to find the pertinent information.

The key points are these: most of our exposure comes from food. Infants, children and adolescents have the highest dietary exposures to BPA, probably because they eat and drink more per kilogram of body weight. The estimated average was 0.375 µg/kg bw per day.  For adult women the estimated average was 0.132 µg/kg bw per day, and for men it was 0.126 µg/kg bw per day.

When it came to thermal paper and other non-dietary exposure (mostly from dust, toys and cosmetics), the numbers were smaller, but the panel admitted there was a fair bit of uncertainty here. The total exposure from all sources was somewhere in the region of 1 µg/kg bw per day for all the age groups, with adolescents and young children edging more toward values of 1.5 µg/kg bw per day (this will be important in a minute).

Note that all of these numbers are significantly less than the, conservative, tolerable daily intake value of 4 µg/kg bw per day recommended by EFSA.

Here’s the important bit: the panel concluded that there is “no health concern for BPA at the estimated levels of exposure” as far as diet goes. They also said that this applied “to prenatally exposed children” (in other words, one less thing for pregnant women to worry about).

When it came to total exposure, i.e. diet and exposure from other sources such as thermal paper they concluded that “the health concern for BPA is low at the estimated levels of exposure”.

The factsheet that was published alongside the full document summarises the results as follows: “BPA poses no health risk to consumers because current exposure to the chemical is too low to cause harm.”

Like I said: Don’t Panic.

What about those frankly quite terrifying headlines? Well, firstly The Sun article was based on some work conducted on a grand total of 208 receipts collected in Southeast Michigan in the USA from only 39 unique business locations. That’s a pretty small sample and not, I’d suggest, perhaps terribly relevant to the readership of a British newspaper. Worse, the actual levels of BPA weren’t measured in the large majority of samples – they only tested to see if it was there, not how much was there. There was nothing conclusive at all to suggest that the levels in the receipts might be enough to “increase your cancer risk”. All in all, it was pretty meaningless. We already knew there was BPA in thermal receipt paper – no one was hiding that information (it’s literally in the second paragraph of the Wikipedia page on BPA).

The Telegraph article, and the many others it appeared to spawn, also weren’t based on especially rigorous work and, worse, totally misrepresented the findings in any case. Firstly, let’s consider that headline: “Plastic chemical linked to male infertility in majority of teenagers, study suggests”. What does that mean? Are they suggesting that teenagers are displaying infertility? No, of course not. They didn’t want to put “BPA” in the headline because that, apparently, would be too confusing for their readers. So instead they’ve replaced “BPA” with “plastic chemical linked to male infertility”, which is so much more straightforward, isn’t it?

And they don’t mean it’s linked to infertility in the majority of teenagers, they mean it’s linked to infertility and it’s in the majority of teenager’s bodies. I do appreciate that journalists rarely write headlines – this isn’t a criticism of the poor writer who turned in perfectly good copy – but that is confusing and misleading headline-writing of the highest order. Ugh.

Plus, as I commented back there, that wasn’t even the conclusion of the study, which was actually an experiment carried out by students under the supervision of a local university. The key finding was not that, horror, teenagers have BPA in their bodies. The researchers assumed that almost all of the teenagers would have BPA in their bodies – as the EFSA report showed, most people do. No, the conclusion was actually that the teenagers – 94 of them – had been unable to significantly reduce their levels of BPA by changing their diet and lifestyle. Although the paper admits the conditions weren’t well-controlled. Basically, they asked a group of 17-19 year-olds to avoid plastic, and worked on the basis that their account of doing so was accurate.

And how much did the teenagers have in their samples? The average was 1.22 ng/ml, in urine samples (ng = nanogram). Now, even if we assume that these levels apply to all human tissue (which they almost certainly don’t) and that therefore the students had roughly 1.22 ng per gram of body weight, that only translates to, very approximately, 1.22 micrograms (µg) per kilogram of body weight.

Wait a second… what did EFSA say again…. ah yes, they estimated total exposures of 1.449 µg/kg bw per day for adolescents.

Sooooo basically a very similar value, then? And the EFSA, after looking at multiple studies in painstaking detail, concluded that “BPA poses no health risk to consumers”.

Is this grounds for multiple hysterical, fear-mongering headlines? I really don’t think it is.

It is interesting that the teenagers were unable to reduce their BPA levels. Because it’s broken down and excreted quite quickly by the body, you might expect that reducing exposure would have a bigger effect – but really all we can say here is that this needs to be repeated with far more tightly-controlled conditions. Who knows what the students did, and didn’t, actually handle and eat. Perhaps their school environment contains high levels of BPA in dust for some reason (new buildings or equipment, maybe?), and so it was virtually impossible to avoid. Who knows.

In summary, despite the scary headlines there really is no need to worry too much about BPA from plastics or receipts. It may be worth avoiding heating plastic, since we know that increases the amound of BPA that makes its way into food – although it’s important to stress that there’s no evidence that microwaving plastic containers causes levels to be above safe limits. Still, if you wanted to be cautious you could choose to put food into a ceramic or glass bowl, covered with a plate rather than clingfilm. It’ll save you money on your clingfilm bills anyway, and it means less plastic waste, which is no bad thing.

Roll on Easter…

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Just what is blk water, and should you drink it?

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Christmas is almost here! Are you ready yet? Are you fed up with people asking if you’re ready yet? Have you worked out what to buy for Great-uncle Nigel, who says he neither needs nor wants anything? Always a tricky scenario, that. Consumables are often a safe fallback position. They don’t clutter up the house, and who doesn’t enjoy a nice box of luxury biscuits, or chocolates, or a bottle of champagne, or spirts, or a case of blk water.

Wait, what?

Yes, this mysterious product turned up in my feed a few weeks ago. It’s water (well, so they say), but it’s black. Actually black. Not just black because the bottle’s black, black because the liquid inside it is… black.

It’s black water.

A bit like… cola. Only blacker, and not fizzy, or sweet, or with any discernable flavour other than water.

It raises many questions, doesn’t it? Let’s start with why. Obviously it’s a great marketing gimmick. It definitely looks different. It also comes with a number of interesting claims. The suppliers claim it contains “no nasties” and “only 2 ingredients”, namely spring water and “Fulvic Minerals” (sic). (Hang on, I hear you say, if it’s minerals, plural, surely that’s already more than two ingredients? Oh, but that’s only the start. Stay with me.)

It claims to “balance pH levels” and help “to regulate our highly acidic diets”. Yes, well, I think I’ve covered that before. Absolutely nothing you drink, or eat, does anything to the pH in any part of your body except, possibly, your urine – where you might see a small difference under some circumstances (but even if you do it doesn’t tell you anything significant about the impact of your diet on your long-term health). And bear in mind that a few minutes after you drink any kind of alkaline water it mixes with stomach acid which has a pH of around 2. Honestly, none of that alkaline “goodness” makes it past your pyloric sphincter.

Finally, blk water apparently “replenishes electrolytes”. Hm. Electrolytes are important in the body. They’re ionic species, which means they can conduct electricity. Your muscles and neurons rely on electrical activity, so they are quite important. Like, life or death important. But because of that our bodies are quite good at regulating them, most of the time. If you run marathons in deserts, or get struck down with a nasty case of food poisoning, or have some kind of serious health condition (you’d know about it) you might need to think about electrolytes, but otherwise most of us get what we need from the food and drink we consume normally every day.

Besides which, didn’t they say “only 2 ingredients”? The most common electrolytes in the body are sodium, potassium, magnesium, chloride, hydrogen phosphate and hydrogen carbonate. Most spring waters do contain some, if not all, of these, in greater or smaller amounts, but it’s not going to be enough to effectively “replenish” any of them. If, say, you are running marathons in the desert, the advice is actually to keep a careful eye on your water intake because drinking too much water can dangerously lower your sodium levels. Yes, there are sports drinks that are specifically designed to help with this, but they taste of salt and sugar and/or flavourings which have been added in a desperate attempt to cover up the salty taste. This is apparently not the case with blk water which, to repeat myself, contains “only 2 ingredients”.

And, according to the blk website the drink contains “0 mg of sodium per 500ml” so… yeah.

Speaking of ingredients, what about those so-called fulvic minerals? Maybe they’re the source of those all-important electrolytes (but not sodium)? And maybe they’re magically tasteless, too?

And perhaps, like other magical objects and substances, they don’t actually exist – as geologist @geolizzy told me on Twitter when I asked.

It’s not looking good for blk water (£47.99 for a case of 24 bottles) at this point. But hang on. Perhaps when they said fulvic minerals, what they meant was fulvic acid – which is a thing, or possibly several things – in a the presence of oh, say, some bicarbonate (*cough* 2 ingredients *cough*).

That could push the pH up to the stated 8-9, and didn’t we learn in school that:
acid + alkali –> salt + water
and maybe, if we’re being generous, we could call the salts of fulvic acids minerals? It’s a bit shaky but… all right.

So what are fulvic acids?

That’s an interesting question. I had never heard of fulvic acids. They do, as it turns out, have a Wikipedia page (Wikipedia is usually very reliable for chemical information, since no one has yet been very interested in spoofing chemical pages to claim things like hydrochloric acid is extracted from the urine of pregnant unicorns) but the information wasn’t particularly enlightening. The page did inform me that fulvic acids are “components of the humus” (in soil) and are  “similar to humic acids, with differences being the carbon and oxygen contents, acidity, degree of polymerization, molecular weight, and color.” The Twitter hive-mind, as you can see, was sending me down the same path…

A typical example of a humic acid.

Next stop, humic acids. Now we’re getting somewhere. These are big molecules with several functional groups. The chemists out there will observe that, yes, they contain several carboxylic acid groups (the COOH / HOOC ones you can see in the example) so, yes, it makes sense they’d behave as acids.

“No nasties”, blk said. “Pure” they said. When you hear those sorts of things, do you imagine something like this is in your drink? Especially one that, let’s be clear, is a component of soil?

Oh, hang on, I should’ve checked the “blk explained” page on the blk water website. There’s a heading which actually says “what are Fulvic Minerals”, let’s see now…

“Fulvic minerals are plant matter derived from millions of years ago that have combined with fulvic acid forming rare fulvic mineral deposits. They deliver some of the most powerful electrolytes in the world.”

“Fulvic minerals contain 77 other trace minerals, most of which have an influence on the healthiness of our body. They are very high in alkaline and when sourced from the ground contain a pH of 9.”

I don’t know about you, but I’m not totally convinced. I mean, as @geolizzy says in her tweet here (excuse the minor typo, she means humic, not humid),  it sounds a bit like… water contaminated with hydrocarbon deposits?

Yummy.

And, by the way, the phrase “very high in alkaline” is utterly meaningless. Substances are alkaline, or they contain substances which are alkaline. “Alkaline” is not a thing in itself. This is like saying my tea is high in hot when sourced from the teapot.

There’s one more thing to add. So far this might sound a bit weird but… probably safe, right? What could be more wholesome than a bit of soil? Didn’t your granny tell you to eat a pinch of soil to boost your immune system, or something? At worst it’s harmless, right?

Tap water is chlorine-treated to keep it free of nasty bacteria.

Maybe. But then again… water is often treated with chlorine compounds to keep it bacteria-free. Now, blk water is supposedly spring water, which isn’t usually treated. But hypothetically, let’s consider what happens when humic acids, or fulvic acids, or whatever we’re calling them, come into contact with chlorine-treated water.

Oh dear. It seems that dihaloacetonitriles are formed. (See also this paper.) This is a group of substances (possibly the best known one is dichloroacetonitrile) which are variously toxic and mutagenic. Let’s hope that spring water is totally unchlorinated, 100% “we really got it from out of a rock” spring water, then.

To sum up: it is black, and that’s kind of weird and a fun talking point – although if you like the idea of a black drink you can always drink cola. It doesn’t balance your pH levels – nothing does. I don’t believe it replenishes electrolyte levels either – how can it when it doesn’t contain sodium? – and I’m dubious about the “2 ingredients” claim (could you tell?). And the oh-so-healthy-sounding fulvic minerals are most likely due to contamination from coal deposits.

All in all, whilst it might not be quite such a conversation piece, I think it would be better to get Great-uncle Nigel a nice box of chocolates this year.

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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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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

What’s all the fuss about glyphosate?

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Glyphosate, the key ingredient in Monsanto’s weedkiller Roundup, has been in the news recently. A few weeks ago it was widely reported that a UN/WHO study had shown it was ‘unlikely to pose a carcinogenic risk to humans‘. But it then emerged that the chairman of the UN’s joint meeting on pesticide residues (who, incidentally, has the fabulous name of Professor Boobis) also runs the International Life Science Institute (ILSI). Which had received a $500,000 donation from Monsanto, and $528,500 from an industry group which represents Monsanto among others.

And then it transpired that there was going to be an EU relicensing vote on glyphosate two days after the (since postponed) UN/WHO report was released, which resulted in another outcry.

Glyphosate molecule

A molecule of glyphosate

So what is glyphosate, and why all the fuss?

It was first synthesized in 1950 by Swiss chemist Henry Martin. It was later, independently, discovered at Monsanto. Chemists there were looking at water-softening agents, and found that some of them also killed certain plants. A chemist called John E. Franz was asked to investigate further, and he went on to discover glyphosate. He famously received $5 for the patent.

Chemically, glyphosate is a fairly simple molecule. It’s similar in structure to amino acids, the building blocks of all proteins, in that it contains a carboxylic acid group (the COOH on the far right) and an amine group (the NH in the middle). In fact, glyphosate is most similar to the smallest of all amino acids, glycine. Where it deviates is the phosphonic group (PO(OH2)) on the left. This makes it a (deep breath) aminophosphonic analogue of glycine. Try saying that when you’ve had a couple of beers.

As is usually the way in chemistry, changing (or indeed adding) a few atoms makes a dramatic difference to the way the molecule interacts with living systems. While glycine is more or less harmless, and is in fact a key component of proteins, glyphosate is a herbicide.

This probably bears stressing. It’s a herbicide. Not an insecticide. A herbicide.

Crop spraying

Glyphosate is a herbicide, not an insecticide.

I say this because people often conflate the two – after all, they’re both chemicals you spray on plants, right? – but they are rather different beasts. Insecticides, as the name suggests, are designed to kill insects. The potential problem being that other things eat those creatures, and if we’re not careful, the insecticide can end up in places it wasn’t expected to end up, and do things it wasn’t expected to do. This famously happened with DDT, a very effective pesticide which unfortunately also had catastrophic effects on certain predatory birds when they ate the animals that had eaten the slightly smaller animals which had eaten the insects that had eaten the other insects (and so on) that had been exposed to the DDT.

Herbicides, on the other hand, kill plants. Specifically, weeds. They’re designed to work on the biological systems in plants, not animals. Often, they have no place to bind in animals and so are simply excreted in urine and faeces, unchanged. Also, since plants aren’t generally known for getting up and wandering away from the field in which they’re growing, herbicide sprays tend to stay more or less where they’re put (unless there’s contamination of waterways, but this can – and should, if the correct procedures are followed – be fairly easily avoided).

Nicotine pesticide

Nicotine is an effective insecticide. It’s also extremely toxic.

Now this is not to say we should be careless with herbicides, or that they’re entirely harmless to humans and other animal species, but we can cautiously say that, in general, they’re rather less harmful than insecticides. In fact, glyphosate in particular is less harmful than a lot of everyday substances. If we simply look at LD50 values (the amount of chemical needed to provide a lethal dose to half of a test population), glyphosate has an LD50 of 4900 mg/kg whereas, for comparison, table salt has an LD50 of 3000. Paracetamol (acetaminophen) has an LD50 of 338, and nicotine (a very effective insecticide, as well as being the active ingredient in cigarettes) has an LD50 of just 9.

Of course, there’s more to toxicity than just killing things, and that’s where it gets tricky. Yes, it might take more than a third of a kilo to kill you outright, but could a smaller amount, particularly over an extended period of time, have more subtle health effects?

But before we go any further down that rabbit hole, let’s take a look at that ‘smaller amount’. Certain campaigners (they always seem to have some sort of stake in the huge business that is organic food, ahem) would have us believe that food crops are ‘drenched’ in glyphosate, and that consumers are eating significant quantities of it every day.

Here’s a great graphic, made by Sarah Shultz of the Nurse Loves Farmer blog (reproduced with her kind permission), that answers this question nice and succinctly:

How much glyphosate?

How much glyphosate is sprayed on crops? (Reproduced with permission of Sarah Shultz)

It’s about 1 can of soda’s worth per acre. Or, if you find an acre hard to visualise, roughly ten drops for every one hundred square feet – the size of a smallish bedroom.

In other words, not a lot. It’s also worth remembering that although there is some pre-harvest spraying – particularly of wheat crops – no farmer is spraying their crops five minutes before harvest. What would be the point of that? Farmers have margins, just like any other business, and chemicals cost money. If you’re going to use them, you use them in the most efficient way you can. The point of spraying pre-harvest is to kill any weeds that might be present so that they don’t get into your harvest. This takes time to happen, so it’s done seven to fourteen days before harvesting takes place. It’s also carefully timed in the growing cycle. Once wheat turns yellow, it’s effectively dead – it’s neither photosynthesising nor transporting nutrients – so if it’s sprayed at this point, glyphosate isn’t moved from the plant into the grain of the wheat. Which means it doesn’t make it into your food.

The long and short of all this is that if there IS any glyphosate in food crops, it’s in the parts per billion range. So is that likely to be harmful?

In March 2015 the International Agency for Research on Cancer (IARC) – the cancer-research arm of the World Health Organisation – announced that glyphosate was ‘probably carcinogenic to humans’, or category 2A. It needs to be pointed out that this outcome was controversial, as this post by The Risk Monger explains. But even that controversy aside, lots of things fall into category 2A, for example smoke from wood-burning fires, red meat, and even shift work. The IARC did note that the evidence mainly involved small studies and concerned people that worked with glyphosate, not the general public, and that recommendations were partly influenced by the results of animal studies (really, go and read that Risk Monger post). The one large-cohort study, following thousands of farmers, found no increased risk.

And by the way, alcohol has been classified as a Group 1 carcinogen, meaning it’s definitely known to cause cancer in humans. If you’re worried about glyphosate in wine and beer, I respectfully suggest you have your priorities the wrong way round.

So, the tiny traces of glyphosate that might be on food definitely aren’t going to poison you or give you cancer. Are there any other health effects?

Gut bacteria

Glyphosate isn’t interfering with your gut bacteria (image: microbeworld.org)

One thing that the health campaigners like to talk about is gut health. Their logic, such as it is, follows that glyphosate passes though our body largely unchanged. Now, you might imagine this would be a good thing, but according to these particular corners of the internet, it’s exactly the opposite. Glyphosate is known to be anti-microbial, and since it’s not changed as it passes through the body, the argument goes that it gets into our guts and starts wiping out the microbes in our digestive system, which have been increasingly linked to a number of important health conditions.

It sort of makes sense, but does it have any basis in fact? Although glyphosate can act as an antimicrobial in fairly large quantities in a petri dish in a laboratory, it doesn’t have a significant effect in the parts per billion quantities that might make their way to your gut from food. Glyphosate prevents bacteria from synthesising certain essential amino acids (it does the same thing to plants; that’s basically how it works) but in the gut these bacteria aren’t generally synthesising those amino acids, because they don’t need to. The amino acids are already there in fairly large quantities; bacteria don’t waste energy making something that’s readily available. In short, glyphosate stops bacteria doing something they weren’t doing anyway. So no, no real basis in fact.

I have so far avoided mentioning GMOs, or genetically-modified organisms. “GMO” often gets muttered in the same breath as glyphosate because certain crops have been modified to resist glyphosate. If they weren’t, it would damage them, too. So the argument goes that more glyphosate is used on those crops, and if you eat them, you’ll be exposed to more of it. But, as I said earlier, farmers don’t throw chemicals around for fun. It costs them money. Plus, not-really-surprisingly-if-you-think-about-it, farmers are usually quite environmentally-conscious. After all their livelihood relies on it! Most of them use multiple, non-chemical methods to control weeds, and then just add the smallest amount of herbicide they can possibly get away with to manage the last few stragglers.

Ah, but even a little bit is too much, you say? Why not eat organic food? Then there will be absolutely no nasty chemicals at all. Well, except for the herbicides that are approved for use in organic farming, and all the other approved chemicals, famously copper sulfate and elemental sulfur, both of which are considerably more toxic than glyphosate by anyone’s measure. And, of course, organic food is much more expensive, and simply not a feasible way of feeding over seven billion people. Perhaps, instead of giving farmers a hard time over ‘intensive’ farming, we should be supporting a mixture of sustainable methods with a little bit of, safe, chemical help where necessary?

In summary, the evidence suggests that glyphosate is pretty safe. Consuming the tiny traces that might be present in food is not going to give you cancer, won’t cause some sort of mysterious ‘leaky gut’ and it’s definitely not to poison you. There is a lot of fuss about glyphosate, but it’s really not warranted. Have another slice of toast.

EDIT 2nd June 2016

After I wrote this post, a very interesting article came my way…

  • Petaluma city suspended use of glyphosate in favour of alternatives. Notable quote:“Having used the alternative herbicides over the past two months, DeNicola said crews have needed to apply the treatments more often to achieve similar results. The plants are also likely to regrow, since the root remains alive underground.The treatments are also said to be extremely pungent during application, with several workers complaining of eye irritation and one experiencing respiratory problems, DeNicola said. Those attributes have required the use of new protective equipment, something that was not required with Roundup.“It’s frustrating being out there using something labeled as organic, but you have to be out there in a bodysuit and a respirator,” he said.”

A classic example of almost-certainly unfounded fear leading to bad decision-making.

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Are you ok? You look a little flushed.

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PrintYesterday was World Toilet Day (yes, really). This is actually an admirable campaign by WaterAid to raise awareness of the fact that one in three people around the world don’t have access to a safe and private toilet. This, of course, leads to unsanitary conditions which results in the spread of infection and disease. You’ve probably never given it a second thought, but loos literally save lives.

portaloo

Has the TARDIS’ replicator function gone funny?

So, with the topic of toilets in mind, I started thinking about chemical loos. If you live in the UK, the name Portaloo ® will probably spring to mind. This has practically become a generic word for a portable toilet, but it is (like Hoover, Sellotape and others) actually a brand name. I’m told that in America they call them porta-pottys or honey-buckets, which I rather like. In any case, all the chemicals and plastic make them seem like modern inventions, surely?

Actually, not at all. The idea of a self-contained, moveable toilet that you can pick up and take from place to place may be newer, but people have been using chemical toilets for hundreds of years. For example after, ahem, ‘business’ had been completed in an an old-fashioned wooden outhouse – basically a tall box built over a hole in the ground – the user would sprinkle a little lye or lime down the hole to help with the smell.

SodiumHydroxide

Don’t get sodium hydroxide on the toilet seat.

Both of these are strongly basic chemicals. Lye is either sodium hydroxide or potassium hydroxide, and lime is calcium oxide. Both mix with water to form extremely corrosive, alkaline solutions and, incidentally, give out a lot of heat in the process. Both are very damaging to skin. These were the days before health and safety; whatever you did, you had to try not to spill it on the seat.

Urea, a key chemical in urine, reacts with strong alkalis in a process known as alkaline hydrolysis. This produces ammonia, which is pretty stinky (if rather tough on the lungs), so if nothing else that helped to cover up other smells. Ammonia also kills some types of bacteria (which is one reason it’s popular in cleaning products). Flies generally don’t like high concentrations of it either, so that’s another plus.

Alkalis also have another effect in that decomposition of human waste is pH dependent; it works better in acidic conditions. Adding lye or lime raises the pH and slows down this decomposition. On top of this (literally) both lime and lye are hygroscopic: they absorb water. This keeps moisture down and allows a solid ‘crust’ to form on the surface of the waste, making it difficult for any volatile, smelly chemicals to escape. Lovely.

Bleach and ammonia could result in a rocket up your...

Bleach and ammonia could result in a rocket up your…

One word of caution: it’s very, very important you don’t try to clean such an outhouse with any kind of bleach. Bleach, which contains sodium hypochlorite, reacts with ammonia to form hydrogen chloride, chlorine gas and chloramine. None of which are good for your health. Even more dramatically (if this is more dramatic than death – you decide) if there’s lots of ammonia you might get liquid hydrazine, which is used in rocket fuels because it’s explosive. Who knew that toilet chemistry could also be rocket science?

But you don’t find buckets of lye in modern chemical toilets (although, apparently, there are still some people out there using it). So what’s in there? At one time, formaldehyde, otherwise known as methanal, was common. You probably recognise it as embalming fluid; the stuff that Damien Hirst floated that shark in. It’s an extremely effective preservative. Firstly, it kills most bacteria and fungi and destroys viruses, and secondly it causes primary amino groups in proteins to cross-link with other nearby nitrogen atoms, denaturing the proteins and preventing them from breaking down.

shark

Don’t worry, this won’t appear in your chemical toilet.

Interestingly, whilst definitely toxic in high concentrations, formaldehyde is a naturally-occuring chemical. It’s found in the bloodstream of animals, including humans, because it’s involved in normal metabolism. It also appears in fruits and vegetables, notably pears, grapes and shiitake mushrooms. The dose, as they say, makes the poison. I mention this because there are certain campaigners out there who insist it must be completely eliminated from everything, something which is entirely unecessary not to mention probably impossible (just for the hell of it, I’m also going to point out here that an average pear contains considerably more formaldehyde than a dose of vaccine).

All that said, because formaldehyde is extremely toxic in high concentrations, and because it can interfere with the breakdown processes in sewage plants (because it destroys bacteria), formaldehyde isn’t used in toilets so much anymore. In fact, many of the mixtures on sale are explicitly labelled “formaldehyde-free”. Modern formulations are enzyme-based and break down waste by biological activity. They are usually still dyed blue (if you work your way though the colour spectrum, it’s probably the least offensive colour), but usually using food-grade dye. As a result, what’s left afterwards is classed as sewage rather than chemical waste, making it easier to deal with.

Toilet twinning So, this has been brief tour around the fascinating world of toilet chemistry. You’d never have guessed there was so much to it, would you? Now, have you considered twinning your toilet?