Chemical du jour: how bad is BPA, really?

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

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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The Chronicles of the Chronicle Flask: 2016

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

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

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

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

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

MCl and MI are common preservatives in cosmetic products

MCl and MI are common preservatives in cosmetic products

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

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

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

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

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

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

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

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

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

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

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

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

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

Sparklers are most dangerous once they've gone out.

Sparklers are most dangerous once they’ve gone out.

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

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

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

See you on the other side!

new-year-1898553_960_720

10 Chemicals You Really SHOULD Be Scared Of

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

8 Things Everyone Gets Wrong About ‘Scary’ Chemicals

scaryChemicals. The word sounds a little bit scary, doesn’t it? For some it probably conjures up memories of school, and that time little Joey heated something up to “see what would happen” and you all had to evacuate the building. Which was actually good fun – what’s not to love about an unplanned fire drill during lesson time?

But for others the word has more worrying associations. What about all those lists of additives in foods, for starters? You know, the stuff that makes it all processed and bad for us. Don’t we need to get rid of all of that? And shouldn’t we be buying organic food, so we can avoid ….

….Read the rest of this article at WhatCulture Science.


This is my first article for WhatCulture Science – please do click the link and read the rest!


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What’s all the fuss about glyphosate?

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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Elements, compounds and misleading mercury

Elemental mercury isn't the same as mercury in compounds.

Elemental mercury isn’t the same as mercury in compounds.

Today I read an interesting article about some recent research carried out at the University of Illinois where they demonstrated that the best way to convince parents to vaccinate their children might be to show them the results of the diseases the vaccines prevent. (This, by the way, contradicts some research published in 2014 which showed that this tactic didn’t work. For an excellent discussion of the two, see here.)

Then, because I am just one of those people who can’t resist poking at ulcers with my tongue (you know what I mean) I had a quick look at some of the comments regarding that article. Reassuringly, most people were weighing in on the “yeah, vaccinate!” side of the argument. But not surprisingly there was also a small group of people posting the traditional anti-vaccine arguments. And then, this appeared:

mercury ppm

This is thoroughly silly, and I’ll tell you why.

Well, it did make be go “hmmmmm”, but for the reason you might imagine.

No, you see, what I thought was: “hmmmmm, someone else who has, possibly deliberately, failed to understood the difference between elements and compounds, and how chemical bonding changes properties.”

Allow me to start at the beginning. If you went to a school in the UK (and I would hope it’s similar elsewhere in the world) you learned about elements, compounds and mixtures when you were about 13 years old – if not before. You might have forgotten it since, but I can absolutely, categorically guarantee you that lesson happened. In fact, it was probably a few lessons.

iron sulfide experiment

The much-loved reaction between iron and sulfur.

One experiment much beloved of chemistry teachers since year dot is to take a mixture of sulfur (a yellow powder) and some iron filings (grey) and show that they can be separated with a magnet. Then heat the mixture up so that the two react, with a rather beautiful red glow, to form iron sulfide. This is a blackish solid which is in theory not magnetic (but in practice almost always is) and demonstrate that now the two elements cannot be separated.

Thus we have demonstrated that elements (the iron and the sulfur) have different properties to the compound they formed (iron sulfide), and also that mixtures can be separated fairly easily, whereas breaking compounds up into their constituent elements is much harder. Lovely. Job done.

And yet… so many people seem to have been asleep that day. Or perhaps just didn’t grasp it well enough to continue to apply the principle to other things.

pouring mercury

Elemental mercury

For example, mercury. Mercury, the element (the runny, silvery stuff that you used to find in thermometers) is a heavy metal. Like most of its compatriots, such as cadmium, lead and arsenic, it’s toxic. It can be absorbed through the skin and mercury vapour can be inhaled, so containers need to be tightly sealed. The increasing awareness of the toxicity of mercury is why older readers might remember seeing it ‘in the flesh’, so to speak, at school, whereas younger ones will not – these days it’s rarely even used in thermometers for fear of breakages.

That said, it does occur naturally in the environment, particularly as the result of volcanic eruptions – and very low levels aren’t considered harmful. The dose, as they say, makes the poison. It also occurs as the result of industrial processes, particularly coal-fired power plants and gold production, and occupational exposure is a genuine concern. In particular, chronic exposure is known to cause cogitative impairment. It might the source of the ‘mad dentist’ myth. It’s almost certainly the origin of the phrase ‘mad as a hatter‘.

So in summary, don’t mess about with elemental mercury; it’s not good for your health.

However, as I took some pains to establish, elements and compounds are different things. So what about compounds which contain mercury?

The compound thiomersal

The compound thiomersal

This is where vaccines come in. There is a substance that used to be used as a preservative in (some) vaccines called thiomersal (or thimerosal, in the U.S). You may have heard its name; it comes up quite a lot. Incidentally, it hasn’t just been used in vaccines, but also in various other things including skin-test antigens and tattoo inks.

Now, to be clear, thiomersal IS potentially toxic, however it’s quickly metabolised in the body to ethyl mercury (C2H5Hg+) and thiosalicylate and, although ethyl mercury does, clearly, still contain atoms of mercury, it does not bioaccumulate. In other words, your body gets rid of it. At very low doses (such as those in vaccines) there is no good evidence that thiomersal is harmful.

Still, due to continuing public health concerns, thiomersal has been phased out of most U.S. and European vaccines. In the UK, thiomersal is no longer used in any of the vaccines routinely given to babies and young children in the NHS childhood immunisation programme. And at the moment, all routinely recommended vaccines for U.S. infants are available only as thimerosal-free formulations or contain only trace amounts of thimerosal (≤1 than micrograms mercury per dose).

Let me just say that again. The evidence suggests it’s safe, but it’s been removed anyway as a precaution. If you live in the UK, it’s not in your child’s vaccines, and that includes the new nasal-spray vaccine for flu which has been rolled out over the last few years. If you live in the U.S. it’s probably not, and thimerosal (thiomersal) free versions exist. It does turn up most often in flu vaccines (hence the meme image at the start) but thiomersal-free versions of those also exist in the U.S.

So chances are it’s not in your vaccines. Not in there. Got it? Ok.

ethyl vs methyl mercury

methyl mercury (left) is not the same as ethyl mercury (right)

Now, you may have heard about mercury in seafood. It is an issue, particularly for women who are pregnant, trying to become pregnant or breastfeeding, and is the reason such women are advised not to eat shark and swordfish, and to keep their tuna consumption low. But here’s the thing: it’s a different kind of mercury. In this case, it’s methyl mercury (remember, thiomersal breaks down to ethyl mercury, which is not the same).

Methyl mercury is more toxic than ethyl mercury. Methyl mercury binds to parts of amino acids much more readily than its ethyl cousin, and it’s able to pass through the blood brain barrier and into nerve cells where it causes damage. In addition, ethyl mercury is much more quickly eliminated from the body than methyl mercury. Because of all this, methyl mercury does bioaccumulate (build up in the body), and that’s why large top-of-the-food-chain fish like shark and tuna can have significant levels of it, and why certain groups of people should be careful about eating them.

The FDA’s action level (the limit at or above which FDA will take legal action) for methyl mercury in fish is 1000 ppb (1 ppm). But remember, that’s for the much more dangerous methyl mercury, not ethyl mercury. I’ve been unable to find an equivalent figure for the UK, but I’d imagine it’s similar.

So, where does the 200 ppb mercury figure in the image at the top come from? Well the Environmental Protection Agency does indeed set a ‘maximum contaminant level goal’ for inorganic mercury of 0.002 mg/L or 2 ppb in water supplies. Methyl and ethyl mercury are not inorganic mercury; compounds that fall into this category include mercuric chloride, mercuric acetate and mercuric sulfide, which largely get into water as the result of industrial contamination.

In summary, that meme image at the start is basically comparing apples and oranges. The EPA limit isn’t relevant to vaccines, because it’s for inorganic mercury, which the substance in vaccines isn’t. While we’re about it, the levels applied to fish don’t apply either, because that’s methyl mercury, not ethyl mercury. They’re not the same thing. And all that aside, it’s highly unlikely (if you live in the UK, no chance at all) that there are 50,000 ppb of ethyl mercury in your flu vaccine anyway. AND, let’s not forget, there’s no evidence that the tiny quantities of thiomersal used in vaccines are harmful in the first place.

Phew.

You may note that I’ve studiously avoided the word ‘autism’ in this post so far. But yes, that’s the big concern; that exposure to thiomersal in vaccines could cause autism. Despite multiple, huge, studies in several countries looking for possible links between vaccines and autism, none have been found. Vaccines don’t cause autism. It’s time we stopped wasting enormous amounts of time and resources on this non-link and spent it instead on finding out what does cause it. Wouldn’t that be far more useful and interesting?

Now… if you’re hardcore anti-vaccine and you’ve read this far, and you’re about to hit the comment button and tell me that all this research is just Big Pharma covering things up so they can make money from the ‘million(/billion/trillion) dollar vaccine industry’, just wait a moment.

Stop.

Think about this: how much money could the medical industry make from people actually catching measles, mumps, polio, TB, whooping cough and all the others? Just think of all the money they could make selling antivirals and antibiotics, all the money to be made from painkillers, antipyretics, drugs to treat respiratory symptoms of one kind or another, and everything else? Believe me, it would be much, much more than they make from a single 2 ml dose of vaccine. Why ‘cover up’ research that’s, if anything, reducing their profits?

All these diseases are horrible, and some can be fatal or have genuinely life-changing consequences. That’s proven. Please vaccinate your children, and yourself.

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