Are you ok? You look a little flushed.

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

portaloo

Has the TARDIS’ replicator function gone funny?

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

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

SodiumHydroxide

Don’t get sodium hydroxide on the toilet seat.

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

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

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

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

Bleach and ammonia could result in a rocket up your…

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

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

shark

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

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

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

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

Basic Chemistry

basic

The other end of the pH scale.

When you start writing a blog it’s hard to predict what people will find most interesting. Inevitably, it’s not what you expected. For example, two of The Chronicle Flask’s most-read posts are about rhubarb and lemons. Perhaps people are more interested in fruit than I ever imagined. Or perhaps I’m getting a lot of hits from people mistakenly looking for recipes.

Or maybe it’s because both feature the ever-interesting topic of acids. In which case, I should probably write something else about acids.

So, this is a post about bases.

Just in case this spectacular bit of contrariness isn’t immediately obvious, bases – some of which are called alkalis (I’m coming to that in a minute) – are at the other end of the pH scale to acids. Acids are the things with a pH value of less than 7, and bases have pH values of more than 7. So basically (hoho), they’re the opposites of acids.

whysoblueI’m using the word base deliberately, and not just because of all the brilliant chemistry puns you can make with it. The more familiar word is probably alkali, but while all alkalis are bases, not all bases are alkalis.

Alkalis are often described as soluble bases. More precisely, alkalis are produced from the metals in group 1 (the ‘alkali’ metals) and group 2 (the ‘alkaline earth’ metals) of the periodic table. The more general term, base, applies to anything that can neutralise an acid. Chemists have another definition: a base is a proton (H+ ion) acceptor, while acids are proton donors (actually chemists have yet another definition, but the proton acceptor one is the one that gets trotted out most often).

The distinction between alkalis and bases does matter to chemists and the two types of substance usually look quite different – bases tend to come in solid lumps or powders (baking soda, for example) and alkalis are more likely to arrive as a solution in a bottle – but in terms of chemistry they both get involved in the same type of chemical reaction, which is neutralising acids.

Indigestion tablet advertWe make use of this all the time, whether we realise it or not. For example if you’re suffering from acid indigestion you probably reach for the indigestion tablets. An advertising campaign for a particular brand of these says that they “turn excess acid into water and other natural substances”. Those ‘natural substances’ are salts – presumably it was decided that the word ‘salt’ had too many negative connotations (which is probably true: how many people would pop a pill that promised to turn into salt in their tummy?) The main ingredient in the tablets in question is calcium carbonate; a base that reacts with stomach acid to produce calcium chloride. Which is definitely a salt, if not the one most people think of when they hear the word.

Tangentially, calcium chloride is also a food additive with the E number E509. It falls into the category of anti-caking agents, which is sort of funny when you think about it.

Anyhoo, that’s one place you use a base (rhyming now as well as punning, sorry). You’re actually making one yourself every time you eat, because your liver produces a substance called bile (bloggers love bile) which helpfully neutralises the acid your stomach produces. If it didn’t, your intestines would get damaged by that acid, so it’s important stuff.

Interestingly, in a lot of the older medical traditions (you know, swallow three leeches with meals, turn around three times under a full moon and bury a toad under a horseradish in a mock turtle) the body’s health depended on the balance of four ‘humors’, or vital fluids: blood, phlegm, ‘yellow bile‘ (choler), and ‘black bile‘. If you had too much of the last two, it was supposed to cause aggression and depression, and in fact the Greek names for them are the root of the words cholera and melancholia.

It’s interesting that in the 21st century many people are obsessed with ‘alkalinizing‘ the body (just check out the comments on that lemons post) when for thousands of years people have understood that too much alkali is probably a bad thing. Public understanding of science has really moved on hasn’t it?

soapBile does something else that’s really quite important in the body, it helps you to digest fats. Bases are generally really good at breaking down fats. This is another thing that’s been known for quite a while, ever since soap was first discovered about (sources vary quite considerably on this) six thousand years ago. Soap is made by a process of saponification, in which fats react with a strong base, usually sodium hydroxide (otherwise known as caustic soda, or sometimes lye). This breaks apart the fat molecules to make glycerol and carboxylate salts (they’re the soap bit). Because of this use, sodium hydroxide features in a famous, and rather gruesome scene, in the film Fight Club.

firediamondNaOH

The fire diamond for NaOH

Because bases are so good at breaking down fats they’re actually surprisingly (or not, if you’ve just watched that Fight Club clip)dangerous, especially because they’re also quite good at breaking down proteins. Your skin is mostly fat and protein, so they can do quite a bit of damage. Remember fire diamonds? The one for sodium hydroxide has a 3 in the blue box, which means that short exposure could cause ‘serious temporary’ or ‘moderate residual’ injury – yikes.

Corrosive hazard symbol

Corrosive hazard symbol

The European hazard symbol is even more alarming, featuring a hand with holes being burned through it. Of course, acids have symbols like these too, but people sort of expect acids to do this kind of stuff. Whereas they’re often (unless they’re chemists) strangely unaware of the dangers of alkalis. For example there’s the a famous, and gruesome, story of the serial killer John George Haigh, who famously dissolved the bodies of his victims in oil drums full of concentrated sulfuric acid. It worked quite well, but he was caught eventually when the police searched his workshop and found sludge containing three human gallstones and part of a denture.

Sulfuric acid is a particularly powerful acid, and is undoubtedly incredibly dangerous stuff, but sodium hydroxide is not much safer. It will cause instantaneous and serious burns, and solid sodium hydroxide gets incredibly hot if it’s added to water. In fact, the water will quickly boil if you’re not careful.

In May last year American Carmen Blandin Tarleton was in the news because she had just received a face transplant. She needed it because her estranged husband had doused her with concentrated sodium hydroxide six years previously. She had undergone fifty-five operations before she made the decision to get the transplant. The pictures are really quite horrific. I won’t reproduce one here; you can see the result of the attack if you follow the link above. Tarleton has also written a book about her experiences. She was left blind and horribly disfigured, with burns to 80% of her body. Doctors described it as “the most horrific injury a human being could suffer”. Sodium hydroxide is not nice stuff.

It’s surprisingly, shockingly, easy to buy sodium hydroxide. Because it’s used in soap-making, you can get it quite easily. It’s even available on Amazon. And of course it’s an ingredient in lots of drain cleaners available in supermarkets. When they say you should wear gloves to handle this stuff, it’s definitely not health and safety gone mad. You really should. Even I would (and I’m really bad about wearing gloves).

So spare a thought for bases. They’re just as interesting, and certainly no nicer or safer than their acidic cousins. In fact, they’re so good at breaking down fat and protein that they could arguably be more dangerous. And next time you’re cleaning out your oven, do remember to wear your gloves.