Tag Archives: chlorine

Non-stick toilets, synthetic poo and saving the environment

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141 billion litres of water are used to flush toilets every day.

“Scientists develop slippery toilet coating that stops poo sticking,” shouted newspaper headlines last week, naturally prompting comments about the state of politics, the usual arguments about the ‘right’ way to hang toilet paper rolls, and puns of varying quality.

There was also more than one person asking WHY, given everything going on at the moment, scientists are spending their time on something which seems, well, not terribly urgent. After all, ceramic toilet bowls are already quite slippery. Toilet brushes exist. We have a myriad of toilet cleaning chemicals. Surely there are higher priorities? Attempting to deal with looming environmental disaster, say?

But here’s the thing, from an environmental point of view, flush toilets are quite significant. If you’re fortunate enough to live somewhere they’re ubiquitous it’s easy to take them for granted, but consider this: flushing even a water-efficient toilet uses at least five litres of water (much more for older models, a bit less if you use a ‘half-flush’ function). Often this is perfectly clean water which has been through water treatment, only to be immediately turned back into, effectively, sewage. Now imagine you have something a bit… ahem… sticky to flush. What do you do? You flush the toilet twice. Maybe more. You break out the toilet brush and the bottle of toilet cleaner, and then you probably flush at least one extra time to leave the bowl clean.

Using toilet cleaning chemicals often results in extra flushes.

Consider that the average person uses the toilet about five times and day and multiply up by the population and, even just in the UK, we’re looking at billions of litres of water daily. Globally, it’s estimated that 141 billion litres of fresh water are used daily for toilet flushing, and in some homes it could account for a quarter of indoor wastewater production. That’s a lot of fresh water we’re chucking, quite literally, down the toilet.

It rains a fair bit in the U.K. so, except for the occasional dry summer, Brits aren’t in the habit of worrying too much about water supply. The opposite, if anything. But we need to change our ways. In a speech in March this year, Sir James Bevan, Chief Executive of the Environment Agency, warned that the U.K. could run into serious water supply problems in 25 years due to climate change, population growth and poor water management.

Even putting those warnings to one side, treating water uses energy and resources. Filters are used which have to be cleaned and replaced, chemical coagulants and chlorine (usually in the form of low levels of chlorine dioxide) have to be added. Sometimes ozone dosing is used. The pH of the water needs to be checked and adjusted. All of these chemicals have to be produced before they’re used to treat the some 17 billion litres of water that are delivered to UK homes and businesses every day. And, of course, the whole water treatment process has to be continuously and carefully monitored, which requires equipment and people. None of this comes for free.

So, yes, saving fresh water is important. Plugging leaks and using water-saving appliances is vital. And, given that everyone has to go to the toilet several times a day, making toilets more efficient is potentially a really significant saving. An super non-stick toilet surface could mean less flushing is needed and, probably, fewer cleaning products too — saving chemical contamination.

Fresh water is a valuable resource.

The new super-slippery surface was co-developed by Jing Wang in the Department of Mechanical Engineering at the University of Michigan. It’s called a liquid-entrenched smooth surface (LESS) and is applied in two stages. First, a polymer spray, which dries to form nanoscale hair-like strands. The second spray completely covers these ‘hairs’ with a thin layer of lubricant, forming an incredibly flat, and very slippery, surface. The researchers tested the surface with various liquids and synthetic faecal matter and the difference — as seen in the video on this page — is really quite astonishing.

Hold up a moment, synthetic faecal matter? I’ll bet no one embarking on an engineering degree ever imagines that, one day, they might be carefully considering the make-up of artificial poo. But actually, when you think about it, it’s quite important. Quite aside from safety aspects and the sheer horror of the very idea, you couldn’t use the real thing to test something like this. You need to make sure it has a carefully-controlled consistency, for starters. It’s the most basic principle, isn’t it? If you want to test something, you have to control your variables.

Artificial poo is surprisingly important.

Indeed, there’s even a scale. It’s called the Bristol stool scale, and it goes from “hard” to “entirely liquid”. Synthetic poo is a mixture of yeast, psyllium, peanut oil, miso (proof, if it were needed, that miso really does improve everything), polyethylene glycol, calcium phosphate, cellulose and water. The amount of water is adjusted to match different points on the Bristol scale. Aren’t science and engineering fun?

Anyway. Back to the non-stick technology. This new surface can be applied to all sorts of materials including ceramic and metal, and it repels liquids and ‘viscoelastic solids‘ (stuff that’s stretchy but also resists flow: apart from poo, PVA slime is another example) much more effectively than other types of non-stick surfaces. In fact, the researchers say it’s up to 90% more effective than even the best repellent materials, and they estimate that the amount of water needed to clean a surface treated in this way is 10% that needed for ordinary surfaces. They were also able to show that bacteria don’t stick to LESS-coated materials, meaning that even if untreated water is used to flush a toilet, it remains hygienic without the need for extra chemicals.

The potential to cut 141 billion litres of water by a factor of ten is not to be (I’m sorry) sniffed at. Plus, in some areas, ready supplies of water and the facilities to clean toilets just aren’t available. Using LESS could, potentially, reduce the spread of infection.

By Chemystery22 - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=31161897 A graft copolymer has side chains branching off the main chain — these side chains are the “hairs” described by the researchers.

So what IS this surface treatment made of? This information wasn’t widely reported, but it seems quite important, not least because applications of LESS are estimated to last for about 500 flushes, which suggests that re-application will be needed fairly regularly and, perhaps more worryingly, whatever-it-is is passing into the wastewater supply.

Not surprisingly, there’s a certain amount of vagueness when it comes to its exact make-up, but I did find some details. Firstly, it’s what’s known as a graft polymer, that is, a polymer chain with long side chains attached — these are the “hairs” described by the researchers.

Secondly, the polymer strands are based on polydimethylsiloxane, or PDMS. This may sound terrifying, but it’s really not. PDMS (also known as dimethicone) is a silicone — a compound made up of silicon, oxygen, carbon and hydrogen. These compounds turn up all over the place. They’re used contact lenses, shampoos, and even as food additives. Oh, and condom lubricants. So… pretty harmless. In fact, they’re reported as having no harmful effects or organisms or the environment. The one downside is that PDMS isn’t biodegradable, but it is something that’s absorbed at water treatment facilities already, so nothing new would need to be put in place to deal with it.

The problem of better toilets might be more urgent than you thought.

Finally, the lubricant which is sprayed over the polymer chains in the second stage of the treatment to make the surface “nanoscopically smooth” (that is, flat on a 1 billionth of a metre scale) is plain old silicone oil, which is, again, something with a low environmental impact and generally considered to be very safe.

As always with environmental considerations it’s about choosing the least bad option, and using these coatings would certainly seem to be a far better option than wasting billions of gallons of precious fresh water.

In short, silly headlines aside, it turns out that making toilets better might be quite an important problem. Maybe it’s time to rage against the latrine.

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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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MMS and CD chemistry – the facts

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The TL:DR version.

The TL:DR version.

About a year ago I wrote a post on the subject of MMS and CD. Many people have since praised that post, but others have complained that it’s rather long (it is) and contains too much opinion.

I believe that anyone that wants them should have easy access to the facts on this subject, and not just the information provided by proponents of MMS/CD use.

With this in mind I’ve written this post as a summary of the basics. I ask only that you credit me if you use this to write an article. A mention of my Twitter account, @chronicleflask, or a link to this page will suffice.

What is MMS?

miracle-mineral-solution-220

MMS is usually sold as water purification drops

MMS stands for ‘master mineral solution’ or sometimes ‘miracle mineral solution’. It is a 22.4% solution of sodium chlorite in water. Sodium chlorite has the chemical formula NaClO2. So, MMS is 22.4 grams of NaClO2 dissolved in 100 mls of water. Sodium chlorite/MMS does not, on its own, act as a bleach.

Sodium chlorite’s LD50 (for rats) is 350 mg/kg. This means that, on average, if you feed rats 350 mg of it per kg of body weight, half the rats will die. If we assume its toxicity is similar in humans (and there’s no reason it should not be) that means that 5.25 grams would probably be enough to kill an average 4-year-old child weighing about 15 kg.

MMS is usually sold as ‘water purification drops’. Search for ‘sodium chlorite water purification’ in Google and you will quickly find it (usually alongside an ‘activator’ solution). Bottles for sale are usually 4 oz, or 114 mls. One quarter of one of these bottles would probably be lethal to a 15 kg 4-year-old.

What is CD (or CDS)?

CD is chlorine dioxide (and CDS stands for chlorine dioxide solution). Chlorine dioxide is ClO2. It is a bleach, used industrially to bleach wood pulp. It is also used to purify water and kill pathogens on certain foodstuffs. It is considered more effective than plain chlorine for water purification – it’s less corrosive and is particularly good at destroying legionella bacteria, as well as many viruses and protozoa.

Chlorine dioxide is more toxic than sodium chlorite. It’s LD50 is 292 mg/kg (the lower the number, the more toxic something is). For this reason, the concentrations used in food/water applications are very low. The US Environmental Protection Agency have set a maximum level of 0.8 mg/L chlorine dioxide in drinking water. That’s 0.00008 grams per 100 ml of water.

What’s the connection between MMS and CDS?

The chemistry of sodium chlorite (the substance in MMS) with acids.

The chemistry of sodium chlorite (the substance in MMS) with acids.

Chlorine dioxide evaporates quickly from solution, which means CD solutions cannot be stored – they have be made freshly as they’re needed. When sodium chlorite is mixed with an acid, usually citric acid (the acid in oranges and lemons), it forms chlorine dioxide. In short:

MMS + acid = CDS.

The chemistry behind this is complicated. It’s simpler if the acid used is hydrochloric acid (HCl), and this particular method of ‘activation’ is sometimes recommended by proponents of MMS/CD use.

If sodium chlorite is mixed with citric acid is used the reaction doesn’t happen in one step. Rather, chlorous acid (HClO2) forms, which ultimately breaks down to form ClO2. Several reactions are involved in this process. The concentration of chlorine dioxide in a solution made in this way is likely to be lower than if hydrochloric acid is used. However, it’s important to realise the the resulting solution is a mixture of harmful substances. Less chlorine dioxide does not necessarily mean safer.

How much chlorine dioxide forms when MMS is ‘activated’?

It’s not possible to answer this precisely, because it depends on several different factors. To begin with, it depends on whether hydrochloric acid or another acid (such as citric acid) is used. It further depends on temperature, and how much acid is added. We have no way of knowing exactly what someone mixing up these solutions at home is doing.

A document on acidified sodium chlorite published by the Joint Expert Committee on Food Additives (JECFA) suggests that, at a pH of 2.3, a 50 ppm solution of sodium chlorite would produce 16 ppm chlorous acid (less at higher pHs). Starting with a 22.4% solution (as in MMS), and allowing for the stoichiometry suggested by the equations above, this could produce something in the region of 36 g of chlorine dioxide per litre of water.

The US EPA’s recommended safe limit for chlorine dioxide is 0.0008 grams per litre of water. Compare this to 36 grams per litre. Even if only a fraction is converted to chlorine dioxide, the resulting mixture is likely to be tens of thousands in excess of safe limits.

How are CD solutions used in food & drink production?

Very dilute solutions, with just a few ppm of chlorine dioxide, are used as sprays or dipping solutions for poultry, meats, vegetables fruit and seafood. However, in these applications the chlorine dioxide evaporates from the food long before anyone eats it – it’s not present in the final food product. Chlorine dioxide is also used in water treatment plants, but the concentration in the final water supply is strictly controlled so that it’s less than the recommended safe limits.

How are CD solutions used as ‘alternative treatments’?

There are groups of people who believe that drinking CD solutions, or using them to perform enemas can cure any and all diseases, illnesses and conditions. However, there is no evidence that CDS is at all efficacious, and no reasonable mechanism has ever been given for its supposed mode of action. Jim Humble, who coined the name MMS ten years ago and sparked the use of these ‘treatments’, claimed that he worked with the Red Cross to successfully treat a group of malaria patients in Uganda. The Red Cross strenuously deny these claims. Other commentators have explained very clearly why Humble’s claims are impossible.

There is a large group online, led by Kerri Rivera, who believe that CD solutions can cure autism. This is not true. Autism is a neurodevelopment disorder. There is no cure, although certain therapies may help those on the autistic spectrum to manage better in day-to-day life. The cause of autism is unclear, but it appears to have a strong genetic basis.

Humble and Rivera advocate drinking CD solutions and/or using them in enemas. Protocols for such treatments involve adding drops of CDS to water, milk or other liquids.

The number of drops used varies. Humble reportedly used 18 drops at a time in his malaria treatment. Usually this is added to further liquid, for example in a 250 ml bottle. Assuming a drop is 0.1 mls, this could be as much as 0.065 g of chlorine dioxide in 250 mls, or 0.26 grams per litre. Once again, US EPA’s recommended safe limit for chlorine dioxide is 0.00008 grams per litre.

The amounts recommended by MMS/CD protocols are likely to be at least 3000 times safe limits, and may be considerably more. Protocols exist which recommend drinking these mixtures every one or two hours, eight times a day or even more.

What would happen if someone drank a CD solution?

It would be ironic if it weren't so tragic.

Chlorine dioxide exposure may actually cause delays in the development of the brain.

It would depend on the concentration. The very low levels used in normal water purification are not harmful (that’s why safe limits exist), however drinking large amounts (such as those usually recommended in MMS/CD protocols) would cause irritation to the mouth, oesophagus, and stomach. There is no evidence that chlorine dioxide causes cancer. The ATSDR‘s (Agency for Toxic Substances and Disease Registry) entry for chlorine dioxide says that “studies in rats have shown that exposure of pregnant animals to chlorine dioxide or exposure of pups shortly after birth can cause delays in the development of the brain” (see also PMID: 2213920).

Why are CDS enemas used, and what would be the effect?

Rivera in particular advocates CDS enemas to kill the ‘parasites’ which she and her followers believe cause autism. There is no evidence for the existence of these ‘parasites’. Photos published online which purport to show them have been condemned as actually showing intestinal lining and mucus, excreted as the direct result of harsh enema procedures.

Enemas, regardless of the liquid used, have risks. Repeated enemas can cause electrolyte imbalance, rupture of the bowel and damage to the rectal tissues. Enemas with CDS are likely to be particularly dangerous since it is corrosive. Proponents of CDS use claim it is ‘selective’ and only kills ‘harmful’ bacteria and parasites. This is not possible; chlorine dioxide is a strong oxidising agent and damages all cells it comes into contact with, regardless of the nature of those cells.

Children have thinner tissues than adults. The risks of regular enemas, particularly with a corrosive agent such as chlorine dioxide, and particularly when carried out at home by someone with no medical training, are likely to be considerably higher for children.

Is there any way to tell if someone has been using CDS in high concentrations?

Unless someone admits to using CDS, there isn’t really any way to tell. For this reason there are very few reported cases of harm caused by CDS, as users tend to be extremely secretive. Unless an enema causes major trauma (which is a real risk) the symptoms are likely to be fairly vague gastrointestinal distress, which could be caused by any number of other things. There is no routine medical test to measure chlorine dioxide or chlorite in the body. There is a special test to measure chlorite in tissues, blood, urine, and feces, but the test cannot tell the extent of the exposure or whether harmful effects will occur. This test wouldn’t be performed unless exposure was expected. In other words, unless someone admits to using CDS on themselves or their child, it’s unlikely anyone will ever find out.

Has MMS/CDS been in the news?

Yes, on several occasions:

If there’s no cure for autism/cancer/some other condition, mightn’t it be worth trying…?

Medicine is all about risks vs. benefits. The benefit of using a particular treatment must always exceed the risk of using that treatment. In this case, there are no proven benefits of using MMS/CDS. There are considerable risks, as described above. The only thing MMS/CDS will do is make you feel sick and generally more unwell than you (or your child) might already. So no, it isn’t worth trying. Please don’t.

Comments will be left open on this page for as long as it takes for me to tire of dealing with “you’re a pharma shill!”, “this is all lies!”, “watch this YouTube video that proves it works!” and “I drink it every day and I’m fine!” type comments. Annnnd that’s it. The most recent “you’re clearly paid off by corporations” comment has been deleted. Comments have been closed. Don’t go and comment on other pages: your comment will not be approved.

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Puzzling pool problems?

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We’re half way thorough the Rio 2016 Olypics, and it will have escaped no one’s notice that there have been a few little problems with one of the pools.

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

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

First, the water turned a mysterious green colour. Then there were reports of a ‘sulfurous’ smell, with German diver Stephan Feck reported as saying it smelled like a “fart”.

The diving pool seemed to be the worst affected, but the water-polo pool next to it also suffered problems, and competitors complained of stinging eyes.

So what on earth was happening? An early suggestion was that copper salts were contaminating the water. It’s not unheard of for copper compounds to get into water supplies, and it would certainly explain the colour; copper chloride solutions in particular are famously greeny-blue. But what about that sulfurous smell? Copper chloride doesn’t smell of sulfur.

Was the strange pool colour due to algae bloom?

Was the strange pool colour due to an algae bloom, like this one in Lake Erie?

The most likely culprit was some sort of algae bloom – in other words rapid algae growth – with the smell probably coming from dimethyl sulfide, or DMS. There’s a singled-celled phytoplankton called Emiliania huxleyi which is particularly famous for producing this smelly compound. In fact, it actually has more than one very important role in nature: the smell is thought to alert marine life that there’s food nearby, but it also seeps into the atmosphere and helps with cloud formation, helping to control our planet’s temperature. Without these reactions, Earth might not be nearly so habitable.

But how did algae manage to grow in the pool? The pool chemicals should have prevented it, so what had happened? An Olympic official then went on to make the comment that “chemistry is not an exact science,” which of course led to much hilarity all around. Chemistry is, after all, incredibly exact. What chemistry student doesn’t remember all those calculations, with answers to three significant figures? The endless balancing of equations? The careful addition of one solution to another, drop by drop? How much more ‘exact’ would you like it to be?

But I had a bit of sympathy with the official, because I suspect that what they actually meant – if not said – was that swimming pool chemistry is not an exact science. And while that, too, is hardly accurate, it is true that swimming pool chemistry is very complicated and things can easily go wrong, particularly when you’re trying to work on an extremely tight schedule. They could hardly, after all, close down all the pools and spend several days carrying out extensive testing in the middle of the sixteen-day-long Olympic Games.

Rio 2016 Olympics Aquatics Stadium (Image: Myrtha Pools)

Rio 2016 Olympics Aquatics Stadium (Image: Myrtha Pools)

When a pool is first built and filled, things are, theoretically, simple. You know exactly how many cubic litres of water there are, and you know exactly how much of each chemical needs to be added to keep the water free of bacteria and other nasties. Those chemicals are added, possibly (particularly in a pool this size) via some kind of automated system, and the pH is carefully monitored to ensure the water is neither too alkaline (basic) nor too acidic.

There’s a certain amount of proprietary variation of swimming pool chemicals, but it essentially all comes down to chlorine, which has been used to make water safe now for over 120 years.

Originally, water was treated to make it alkaline and then chlorine gas itself was added. This produced compounds which killed bacteria, in particular sodium hypochlorite, but the practice was risky. Chlorine gas is extremely nasty stuff – it has, after all, been used as a chemical weapon – and storing it, not to mention actually using it, was a dangerous business.

However, hundreds of people swimming in untreated water is a recipe for catching all kinds of water-borne disease, so it wasn’t long before alternatives were developed.

The Chemistry of Swimming Pools (Image: Compound Interest - click for more info)

The Chemistry of Swimming Pools (Image: Compound Interest – click graphic for more info)

Those alternatives made use of the chemistry that was happening anyway in the water, but  allowed the dangerous bit, with the elemental chlorine, to happen somewhere else. And so hypochlorite salts began to be manufactured to be used in swimming pools.

As the lovely graphic from Compound Interest illustrates, sodium hypochlorite reacts with water to form hypochlorous acid, which in turn goes on to form hypochlorite ions. These two substances sit in an equilibrium, and both are oxidants, which is good because oxidants are good at blasting bacteria. The equilibria in question are affected by pH though, which is one reason why, quite apart from the potential effects on swimmers, it’s so important to manage the pH of pool water.

There are a couple of different chemicals which can be added to adjust pH. Sodium bicarbonate, for example, can be used to nudge the pH up if needed. On the other hand, sodium bisulfate can be used to lower pH if the water becomes too alkaline.

Open-air pools have particular problems

UV light breaks down the chemicals that are used to keep swimming pool water clean.

This can all be managed extremely precisely in an unused, enclosed pool. But once you open that pool up, things become less simple. Open-air pools have a particular problem with UV light. Chlorine compounds are often sensitive to UV – this is why CFCs are such a problem for the ozone layer – and hypochlorite is no exception. In the presence of UV it breaks down in a process called photolysis to form chloride ions and oxygen. This means that outdoor pools require more frequent treatments, or the addition of extra chemicals to stabilise the ‘free available chlorine’ (FAC) levels.

Sadly, I haven’t managed to make it over to Rio, but from what I’ve seen the Aquatic Centre has a roof which opens up, which means that the pool water is indeed being exposed to UV light.

So perhaps the chemical levels simply dropped too low, which allowed algae to proliferate? Possibly aggravated by environmental conditions? Indeed, initially this seemed to be the explanation. FINA, the international governing body of aquatics, issued a statement on Wednesday afternoon which said:

“FINA can confirm that the reason for the unusual water color observed during the Rio diving competitions is that the water tanks ran out of some of the chemicals used in the water treatment process. As a result, the pH level of the water was outside the usual range, causing the discoloration. The FINA Sport Medicine Committee conducted tests on the water quality and concluded that there was no risk to the health and safety of the athletes, and no reason for the competition to be affected.”

This prompted people to wonder how on earth chemical levels were allowed to run out in an event as significant as the Olympics – did someone forget to click send on the order? – but still, it seemed to explain what had happened.

FINA issued a new statement

FINA issued a new statement on Sunday

Until today (Sunday), when more information surfaced as Olympic officials announced that they were going to drain at least one of the swimming pools and refill it. This is no small feat and will involve considerable cost: after all, we’re talking about millions of gallons of water. But it seems to be necessary. As Rio 2016’s director of venue management Gustavo Nascimento said:

“On the day of the Opening Ceremonies of the Games, 80 litres of hydrogen peroxide was put in the water. This creates a reaction to the chlorine which neutralises the ability of the chlorine to kill organics. This is not a problem for the health of anyone.”

Whoops. Yes indeed. Hydrogen peroxide reacts with chlorine to produce oxygen and hydrochloric acid. In fact, hydrogen peroxide is actually used to dechlorinate water which contains levels of chlorine that are too high. It might not be the very worst thing you could add to the water (when you think of all the things that could end up swimming pools) but it’s definitely up there.

Why and how this happened doesn’t, at the moment, appear to be clear. Presumably someone is for the high jump, and not just on the athletics field.

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Liquid calcium? Why words really matter in chemistry

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dl-265_1zI happened to see an advert for Arm & Hammer toothpaste on TV a couple of days ago, in which they cheerfully proclaimed that it contained “liquid calcium”.

navigator_highlighted_periodic_table

Calcium, on the left. With the metals.

This brought me up short.  First thing: calcium is a metal.  Now, as a famous British movie star might say (or perhaps might not say), “not many people know that”.  Ask a roomful of people if calcium is a metal and most of them will tell you it’s not.   I’ve even heard students who know what the periodic table is and what the position of elements within it means, and who can see calcium right there on the left hand side, express their doubts.  Everyone associates calcium with bones and teeth, possibly rocks at a push.  No one (other than chemists of course) hears ‘calcium’ and thinks of a silvery-grey metal.

But that is indeed what it is.  It is a metal, and although its melting point isn’t huge in the grand scheme of metals, it’s still a fairly substantial 842 oC.  The temperature in your bathroom is probably in the region of 20 oC.  In fact your kitchen oven probably only goes up to about 240 oC, so the melting point of calcium is some 600 oC hotter than the hottest setting on your oven.

ca_2_2

Calcium and water: what you can’t see is how hot this sucker is going to get.

Temperature problems aside, pure calcium is also highly reactive.  Drop some in water and you’ll see a lot of violent bubbling followed by the solution turning white as a corrosive calcium hydroxide solution forms.  The bubbling is due to flammable, potentially explosive, hydrogen gas.  Oh, and it will get really, really hot too – this is what chemists call an exothermic reaction.  I for one will confess to once (many, many years ago, of course) dropping a red-hot boiling tube into which I’d popped just a little too much calcium metal.  After it had also bubbled up and covered my hand with the aforementioned calcium hydroxide.  Ooopsie.  (Fear not, my hand survived unscathed, after the application of copious amounts of cold water – the go-to cure for most chemical exposures).

So, at the risk of stating the obvious, there’s no liquid calcium in Arm & Hammer toothpaste.  And a jolly good thing too.

What is there?  At this point I should probably point out that Arm & Hammer are quite careful, in their literature and on their packaging, to always put a little ™ by “Liquid Calcium”.  A quick glance at their website clarifies that they’re talking something called “Liquid Calcium ™ Technology” which refers to an ingredient that contains “up to 8 times more calcium and phosphate ions than the amount found in saliva so it is able to replenish ion content in your mouth and subsequently re-mineralise and protect your teeth more efficiently.”

Ah, now we get to the truth of the matter.  It’s not liquid calcium, but calcium ions in solution.

Does this matter?  Am I being unnecessarily pedantic?  Liquid/solution, calcium metal/calcium ions, what’s the difference?

H2O2

When an extra O really matters.

Well, the thing is, chemists are pedantic.  See, in chemistry, it genuinely could be a matter of life and death.  Ethanol, for example, is ‘drinking’ alcohol.  It’s the stuff in beer, and wine, and strawberry daiquiris.  It may not be exactly healthy, but most adults can consume some fairly safely.  Ethanal, on the other hand, is a toxic and probably carcinogenic substance that’s mainly used industrially as a starting point to make other chemicals.

To pick another example, chlorine is a highly toxic gas that’s been used in chemical warfare; chloride ions are found in salt and are consumed perfectly safely every day.  The difference between ions (atoms or molecules which have become charged due to the gain, or loss, of electrons) and atoms is really quite critical in chemistry, and in life in general.

potassium and water

Potassium reacting with water – pretty!

‘Everybody’ knows that bananas contain lots of potassium.  But potassium is another highly-reactive metal.  In fact it’s even more reactive than calcium.  Potassium explodes with a rather beautiful lilac flame in contact with water.  It’s pretty to watch, but you wouldn’t want it in your mouth.  Actually bananas contain potassium ions (and just to really mess with everything you thought you knew, not even that much compared to lots of other foods).

Back to the dubious labelling again, It’s interesting that Arm & Hammer have chosen to say “fluoride” – which specifically, and correctly, refers to fluoride ions – and not “liquid fluorine”.  I mean surely, in the spirit of consistency, it should be liquid fluorine and liquid calcium (argh!), or fluoride ions and calcium ions.

The word liquid has a specific meaning in chemistry.  It means a pure element or compound in its molten state.  Pure water at room temperature is a liquid.  So is ethanol, and mercury, and bromine (interestingly these last two are the only chemical elements which are liquids at room temperature).  Ethanol dissolved in water, as it is in strawberry daiquiris (more or less), isn’t a liquid.  It’s a solution.  This matters.  Liquid ethanol is pure ethanol.  Drink that and you’re looking serious alcohol poisoning in the face, and it’s about to wallop you for looking at it funny.

frustration_350px

An Arm & Hammer chemist?

Saying, or even implying, that calcium ions in solution is ‘liquid calcium’ is like saying that seawater is liquid sodium (sodium is another highly reactive metal – orange flame this time).  It’s just nonsense.  Ok, it’s probably not going to cause anyone any actual harm, but that’s not the point.  It’s completely factually inaccurate.  I am absolutely certain that the chemists working for Arm & Hammer wanted to tear their hair out when the advertising company came up with this name for the formulation they’d spent (probably) years slaving over.  And I expect they were essentially told to shut up about it, the vast majority of our customers won’t know the difference.

And sadly this may be true.  But it shouldn’t be.  Would Arm & Hammer care if their boxes were labelled ‘tothpast’ instead of toothpaste?  I bet they’d be bothered if the boxes were priced at £250 instead of £2.50.  Why fuss over spelling and numbers but be careless over scientific literacy?  Either precision matters or it doesn’t.

Perhaps it’s time scientists starting making as much noise about this kind of thing as people who complain about stray apostrophes or the misuse of the word disinterest.  You never know, it might help levels of scientific understanding.

Mind you, perhaps the author of a blog called The Chronicle Flask shouldn’t throw stones…

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After I wrote this post I tweeted something referring to “liquid phosphorous”.  It was pointed out to me, quite rightly, that I meant “liquid phosphorus”.  Phosphorus is the noun – the name of the chemical element – and phosphorous is an adjective.  As in, “phosphorous fertiliser”.  I confess I was a bit hazy on that one until made to check, which is ironic really. Consider me sent to the back of the class 😉