Toxins and tanks: could your fishtank really be deadly?

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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I love my naturally-occurring pesticide

mugs

You can buy one of these fantastic mugs from MugWow – click on the image for details.

99.99%, by weight, of all the pesticides we consume are naturally-occurring.

That’s a pretty amazing statement, isn’t it? It comes from a paper about dietary pesticides that was published in 1990, and referred to the American diet, but it’s almost certainly still not far from the truth – pesticide use, despite what some of the crazier corners of the internet will tell you – hasn’t increased significantly in the last 26 years. The authors of the paper concluded that “the comparative hazards of synthetic pesticide residues are insignificant” and it’s a valid point. Many of these natural pesticides – chemicals which plants use to defend themselves – have never been fully tested, and some of them are actually well-known toxins.

Plants have been on this planet for a very long time, 700 million years give or take, which means they’ve had an awful lot of time to evolve defences. Some of these are physical, like thorns or spines, but chemistry plays a key role.

For example, one of the most common toxins is solanine. It turns up in potatoes which, as any good gardener will tell you, are part of the nightshade family. Yep, like deadly nightshade. But don’t panic, it’s mostly in the parts of the plant we don’t eat, namely the leaves and stems, with only very small amounts found in the skin and virtually none in the flesh.

DO NOT EAT!

DO NOT EAT THESE!

Unless, that is, your potatoes are exposed to light. Then the tubers start producing lots of extra solanine (and another alkaloid called chaconine), as a defence to stop the uncovered tuber from being eaten. At the same time, they produce extra chlorophyll, which causes them to turn green. The chlorophyll is harmless, but the solanine most definitely is not. It causes vomiting and diarrhoea, and can even be fatal – although this is really only a risk for people who are undernourished. Still, if your potatoes have turned green its safest to throw them out, since cooking doesn’t break the toxins down. Even if they’re not green, if they have a bitter taste it’s safest to get rid of them if you don’t want to risk an extended visit to the porcelain throne.

But solanine is just the tip of the lettuce. Capsaicin (the stuff in chillies) also evolved as a defence mechanism to repel and kill insects, and there’s evidence that it may be carcinogenic under some circumstances. 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one (DIMBOA) is another chemical which is found in corn, wheat, rye and other grasses and which has been shown to cause carcinogenic changes in human cell lines. Then there are all the various substances in herbs and spices, such as tetradecanoic acid in nutmegpulegone in peppermint, carvacrol in oregano and eugenol in cloves, nutmeg and basil.

But not to panic. None of these chemicals are dangerous in the quantities that we usually consume them. And neither, while we’re here, are the really teeny, tiny amounts of synthetic pesticides that we might be exposed to. So just relax and eat your greens. Well, not if they’re potatoes. You know what I mean.

Anyway, there’s one substance I haven’t mentioned yet, and it’s a biggie – it’s something most of us consume on a regular basis. In fact, it might be the source of over a gram of naturally-occurring pesticide a day, and few of us even give it a thought.

What is it? Coffee. Yes, your daily dose of americano is a veritable cocktail of chemicals. As the dietary pesticides paper points out, “13 g of roasted coffee per person per day contains about 765 mg of chlorogenic acid, neochlorogenic acid, caffeic acid, and caffeine.” A single espresso shot uses about 8 grams of ground coffee, so a mere two shots will take you up to best part of a gram of chemically-goodness, and who restrains themselves to two shots a day?

But there’s good news. Some of these substances could actually be beneficial. Chlorogenic acid appears to moderately lower blood pressureNeochlorogenic acid might actually help to prevent certain cancers, as might caffeic acid (although results are mixed in this case).

caffeine

The world’s most widely-consumed psychoactive drug.

And then, of course, there’s caffeine itself – the world’s most widely consumed psychoactive drug. It has umpteen (technical term) effects not the body, both positive and negative, the most famous being its ability to keep us alert and awake. It’s performance-enhancing and its use was at one point restricted for Olympic athletes, until 2004 when officials decided to remove those restrictions – presumably because they were proving impossible to enforce.

But caffeine didn’t evolve for the convenience of humans, although we have, of course, played our part in farming and selectively-breeding plants. No, it originally evolved to paralyse and kill predator insects. Basically, to stop the plant being eaten which, from the plant’s point of view, is quite important. Interestingly, there’s evidence that it evolved separately in coffee, tea and cacao, suggesting it really is a pretty advantageous thing for a plant to make. But in case you’re wondering, it’s broken down by UV light, which explains why it’s not used as an insecticide spray on other plants.

So, if you’re worrying about pesticides with a cup of coffee in your hand, you can stop. You’re probably consuming more pesticide, daily, than you will get from carrots in your lifetime. Drink up!


mugs

Do you love your naturally-occurring pesticide?

The competition to win one of these mugs has now closed. For details of the winner, see this Facebook page. But if you were unlucky, never fear – you can buy one of your very own from MugWow. Use the code flask15 and you’ll even get a 15% discount – go on, you know you want to!


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A scary Halloween tale…

Food additives, E-numbers – they’re scary aren’t they? Everyone knows they’re horrible, toxic things that make kids jump around, refuse to go to bed, go purple in the face and generally drive their parents around the bend (do kids really need chemical help with any of those things?)

pumpkin eating

Be careful what you eat…

It’s Halloween, a day when children traditionally stuff their faces fully of sugary, brightly-coloured sweeties. But never mind those, let’s give some thought to the humble pumpkin. Yes the orange things that grow in the ground. Did you know they’re stuffed full of additives too? Even ‘organic’ ones? They are, really! Here’s an ingredients list…

Water, carbohydrate, protein, E300, E375, E101, pyridoxine, thiamine, E470a, pteroyl-L-glutamic acid, E306, E160a, palmitic acid, linoleic acid, oleic acid, palmitic acid, stearic acid, purines, E621, potassium, calcium, phosphorous, magnesium, sodium, iron, zinc.

Scared yet?

Ok ok, don’t panic. Put down the baseball bat. It’s all right really, allow me to translate…

E300 is ascorbic acid, otherwise known as vitamin C. E375 is niacin (vitamin B3). E101 is riboflavin (vitamin B2). Pyridoxine is vitamin B6. Thiamine is vitamin B1 (seeing a pattern here? Pumpkin is good for B vitamins). E470a represents potassium salts of fatty acids. Pteroyl-L-glutamic acid is another name for folic acid. E306 is tocopherol, or vitamin E. E160a is beta-carotene (vitamin A).

Palmitic acid is the most common fatty acid found in animals and plants, and linoleic, oleic, palmitic and stearic acids are essential fatty acids particularly found in pumpkin seeds (very tasty roasted). Purines are some of the building blocks of DNA (the word purine comes from ‘pure urine’ because they were first synthesised from uric acid, isolated from kidney stones – ewwww). E621 is the dreaded monosodium glutamate. A lot of people fear this one, but actually it’s just a sodium salt of glutamic acid, which is another key amino acid. Totally natural. In fact, it’s one of the most abundant naturally occurring non-essential amino acids. (I will confess I’m improvising a wee bit here, but there’s no doubt that there’s glutamic acid in pumpkin – very abundant amino acid see – and there’s also sodium, so chances are there’s some monosodium glutamate knocking around in there.)

Potassium, calcium, phosphorous, magnesium, sodium, iron and zinc are all elements, and also important nutrients – you’ll find them all listed on the back of any good multivitamin and mineral supplement.

Food for thought? There’s a lot of nonsense spouted about additives and E numbers. For starters, that E? It means they’re regulated food additives that have been tested and approved for use with the European Union. They are, by definition, safe. Not only that, but quite a few of them are in your food to keep you safe by preventing harmful bacteria growing in it, for example. Lots and lots of them come from natural sources. Chemists like to extract and identify things, which is why lots of entirely natural substances have ended up with chemical names. An unfamiliar and complicated-sounding name doesn’t make something inherently dangerous.

On the other hand, there is something that’s been proven time and time again to cause numerous health issues from crashing energy levels to obesity, type two diabetes and dental problems. Yup. Sugar. E numbers have nothing on it.

I’m not suggesting anyone gives up sugar (where would be the fun in that, especially on Halloween?) but it’s always worth thinking about relative risk. If you’re going to accept a bit of sugar isn’t the end of the world, then give additives a break as well.

Right, I’m off to eat some Halloween biscuits – trick or treat!