Thursday, 11 August 2016

The health risks of chlorinated pools

When you combine water with sunlight and open air, life tends to  happen. Now, that’s an amazing thing, but far from ideal if you want to use a body of standing water for anything sanitary. For decades, there’s been a pretty clear cut solution to this – chlorine.

While some are salted, most swimming pools are chlorinated. Once chlorine solution is added to water, it breaks down into hypochlorous acid and hypochlorite ions, which attack the lipids in bacterial cell walls. This oxidises the cells and renders them inert. It’s a remarkably effective process, but it makes the water toxic.

If you’ve ever swallowed a mouthful of pool water, you’ll know that it’s a thoroughly unpleasant experience, accompanied by a lot of coughing and gagging. That’s not actually anything to do with the chlorine, though. Even in a heavily chlorinated pool, the rate is about 2 parts per million, so even if you drank the whole pool, you wouldn’t get chlorine poisoning. What would poison you, would be all the nasty bacteria that chlorine can’t kill.

We have to examine the health risks of swimming in a chlorinated pool on a regular basis, as many people are currently doing, either to deal with the summer heat or because watching the Olympics has made them feel particularly out of shape. So, is there any danger of ill-health as a result of all this splashing around?

It’s still a debated subject, but to suggest that there’s no risk would be very naïve. One Belgian study, conducted in 2009, found that teens who very regularly swam in chlorinated pools were at higher risk from asthma and other allergies. In particular, the risk of hayfever doubled. Another study found, that when chlorine combines with urine, it was develop an irritant called trichloramine, which could well cause damage to the cellular walls which protect the lungs. It’s been theorised that the presence of this irritant could be putting children at greater risk of asthma.

Indoor pools have their own inherent issues, due to the fact that they are an enclosed space. Chloramines release gas into the air, and if it gets trapped in such a space, people will inevitably breathe it in. The build-up of chloramines in the air can be accelerated by the surface of the water being broken, and that’s kind of a given at a busy pool. All indoor pools are required to have some kind of ventilation system, but their effectiveness can vary dramatically. Inhale enough and you could be at risk of respiratory irritation, same as if you swallowed the water.
Fundamentally, most of the issues caused by chlorinated water are more due to the sanitation of the pool in question. If a lot of people are peeing in it, or doing anything else similarly disgusting, the health risk of being in or even near that water obviously rises. Equally, if the pool isn’t cleaned regularly or excess chlorine is pumped in to account for the unsanitary water, that’s also bad news.

The bottom line is this – if you’re going to swim regularly, do some serious research on how well maintained the pool is, and keep an eye on it when you’re there. Olympic or athletic swimming pools tend to be a better bet, simply because there’s more money involved. If you have children, it’s almost better to (if you can afford to) get your own above ground pool and use that; public recreational pools are often filthy during the busy summer months. In any case, chlorine is an excellent disinfectant, you needn’t worry about that, it’s just the people who use the pools you need to be careful of.

What's in a wave?

Imagine looking out at sea,  waiting for that moment, a split second where instinct kicks in and says 'GO', tunnel vision on the patch of blue that’s gargling into adolescence and then catching it as it grows into adulthood.  You can’t tame it, with instinct and your surfboard you’re looking to own it at the expense of it possibly engulfing you; you do this with instinct and your surfboard.

It seems that good surfers have a keen eye for spotting where and when the perfect wave will break. The surfer uses their instinct to see the future of the landscape, but what is it that creates that perfect wave? 

The surfer’s perspective

Sat out upon the rolling sea, from the surfer’s perspective, the landscape at that point is an endless blue littered with the froth created by the wind chopping up the surface of water - these are called white-caps.

The whitecaps can form crests giving the wind more surface area to work with, creating a peak. Those small peaks start moving away from the wind, expending a bit of its energy by turning its choppiness into a nice rounded wave, which is called a swell. 

At this point it seems pretty weak and unassuming, as all that energy is underwater. This energy becomes apparent when the waves get closer to the shore and starts making contact with the land underneath. As the wave begins encroaching upon the land the wave's energy is forced upward above the water surface, the front of the wave slows before the back of the wave causing to break; here we have the rideable wave.

The shape of the land beneath the water has a say in how the wave turns out; if the land is steep the wave will crash creating a barrel wave, if the slope of the land is more gradual then the wave will break slowly forming a ‘crumbling’ wave. 

 Barrel wave                                                                                        Crumbling wave
Img source (right):

The physics of the wave

The waves make their way onto the shore in rows; sometimes the ones behind can catch up with the wave in front and add together creating a super wave. This is simply constructive interference.

If you picture the wave from the side you can see it as a series of orbital waves. This motion is a flow of energy from peak to the trough and back round again, making what is basically a large circle. When it comes into contact with the land this circular motion is forced upwards, essentially squishing it and disrupting the circular flow of the water, which causes the wave to break.

We know what creates the ideal wave and now we have the technology to actually make an artificial one. Professional surfer, Kelly Slater, rode an artificial wave in 2015. After years of research it was discovered that the best way to simulate barrel waves in the ocean was to use the wind (pneumatics). This was the wave that Kelly Slater surfed. 

By simulating ocean swells we can replicate an experience that is closely comparable to ocean surfing. Engineers have designed hundreds of wave pools for water parks, but the technology incorporated to make surfing waves today is a quantum leap in the evolution of surf pool technology. 

In the right conditions the water flowing back to the sea can form a rip current. This is the term for the water that’s moving from the shore back to the sea; the current can drag swimmers into the open water at a speed that’s too difficult to swim against. 

The weather can also change the intensity of the wave. For instance strong winds and pressure from a hurricane can create a series of waves that are formed in deep water, which intensify as they approach land.

The land at the bottom of the water can also massively affect the wave; Tsunamis for instance, are due to the land under the water shifting – different to tides which are created on the surface by wind and the magnetic force from the moon and sun. Tsunamis are caused by the energy beneath the surface; a volcanic eruption, submarine landslide or an earthquake can cause this huge surge of energy underwater that eventually makes its way onto the surface as it comes closer to the shore. 

Whilst the physics perspective is equally as stunning as the surfer's, encouraging a safer perspective on the waves, nothing jars the surfer’s instinct; that wave is theirs for the taking and admittedly, it’s infectious… Let’s go surfing. 

Wednesday, 10 August 2016

Seabins - Clearing the waste of the ocean

Oceanic waste is a huge problem, and it’s growing by the year. Despite all the warnings, the rate of global plastic production continues to rise, and you only need to visit a popular beach to see the extent of the problem. Fish and seabirds alike are frequently found dead, with plastic in their digestive systems, and the ocean is blighted by floating islands of the stuff, centuries away from even beginning to decompose.

The primary approach to solving the problem is obvious, but daunting – significantly downsize plastic production and upscale recycling. The latter is already happening, but nowhere near enough to counteract the gargantuan scale of plastic production, and more to the point, the scope for reusing many types of consumer plastic is actually pretty narrow. 

Even if, by some miracle, we were able to stem the tide of plastic production and discarding to the point where it balances things out again, there would still be millions upon millions of metric tons of plastic still out on the ocean, and no, I’m not exaggerating. Beach clearing and trawling will only get you so far when there’s just so much of it, so one idea is to create a kind of device which can be placed in the water and just left to get on with the task at hand.

Enter the ‘Seabin’, an ingenious little solution invented by two Aussie surfers – Andrew Turton and Pete Ceglinski – and it’s currently in the final research phase. At a glance, it just looks like a bin with a yellow rim and a sleek chrome finish, but there’s a lot more than meets the eye. They are fitted to pontoons, lowered until the rim is just slightly beneath the surface and then a suction engine whirs to life, drawing waste inside until the bag is full. 

The trash can then be sorted and recycled. Because the bin sits so close to the surface, fish aren’t in any danger of being mistakenly sucked in, as extensive tests have proven. The pump is solar powered, and has been tested in several countries already, with many marine authorities across the world saying that they also want to try it out. The team are looking at making them available in 17 countries from 2017 onwards.

If these wonderful little bins could be distributed in a more widespread manner, they could provide an effective solution to the issue, at least inland where they can easily be accessed and emptied on a regular basis. The open ocean is another issue entirely, but there’s no reason why the technology couldn’t be refitted to work on a larger scale, with fleets of bins cast out, and then collected at the end of the day by large ships.

Of course, active solutions can’t work all by themselves, and the introduction of technology like this has to be mirrored by the reductions in consumption I was talking about before. The Seabins can act as a barrier between the trash and getting out onto the open ocean, but even if they were on literally every beach, marina and pontoon in the world, trash would still find its way out to sea. We need companies to reduce their plastic footprint, or all the research and development in the world simply won’t be enough. The Olympics are evidence enough of that.


Tuesday, 9 August 2016

Water in religion

Water holds special significance in many cultures and religions, primarily due to its cleansing, life-giving properties. Believers of various religions use water in ritual washing to purify themselves, both literally and spiritually, in preparation for worship or contemplation. 

Water is widely regarded as one of the basic elements, along with fire, earth, air, and sometimes space, which has led to it being considered all over the world as the sacred foundation of all life.

Sacred texts such as the Qur’an, Bible, and Vedas are full of imagery that uses water, the abundance or lack of it, to explain and symbolise spiritual health and blessings.  Floods, rains, storms, waves, aridity and drought feature heavily, and carry particular relevance for cultures living in harsh desert climates, for whom water is the essential, precious resource.


The belief that water is the source of life, and point of origin and creation, is shared by many religions. The Hindu text Rig-Veda describes how ‘in the beginning everything was like the sea and without light.’ Water precedes the creation of life and light, and initiates the process, as the creator god Brahma was born from the water (jal). 

The Bible’s account offers a similar picture: ‘The earth was formless and empty, and darkness covered the deep waters.’ The spirit of God was said to hover over the waters before the creation of anything else.  

In the Qur’an, it says that every living thing was made from water, which existed before anything else as the seat of God: ‘And it is He who created the heavens and the earth in six days, and his Throne was upon water.’

The Native American Hurons tell that in the beginning there was only one water and the water animals that lived in it. A divine woman fell from the sky and animals dove down to fetch earth to make her some land to live on.

Ceremonies and Washing Rituals

Many ceremonies in Hinduism, Islam, Christianity, Judaism, Shinto, Taoism, Zoroastrianism, and countless others involve water in some way. Believers are often immersed, sprinkled, or washed in pure water before participation in marriage, death, birth, and affirmations of faith, among others.

For many, bathing a newborn baby is an important ritual. Hindus practice different ceremonies for birth, depending on the region. One involves washing the child in milk and water from the sacred river Ganges to purify and cleanse sins from its past lives. Christians believe baptising or christening a baby welcomes them into the church family and washes away original sin. 

In Sikhism, believers have an Amrit ceremony when they are old enough to commit to their faith. Sweet water stirred with a double-edged sword is drunk and sprinkled on the hair and eyes.

Washing is an important part of everyday prayer for Muslim, Shinto, Zoroastrian, Jewish and Hindu worshippers, who cleanse themselves of pollution and impurity before offering their devotion.

Wudu is the essential washing of hands, arms, face, ears nose, head, and feet that Muslims must perform before Salaat. It must be repeated if an action is carried out that nullifies Wudu, such as passing gas, urination, bleeding, natural discharge, and deep sleep. 

Purification called Harae is necessary before a Shinto worshipper can bring an offering to the Kami, revered gods that inhabit natural spaces, like mountains, trees and rocks. Waterfalls are sacred, and to stand under one is a cleansing ritual.

Concerns of purity are central to Zoroastrianism, and the ritual of padyab-kusti is carried out to cleanse minor pollutions. More serious pollutions such as touching a dead body require a nine day baresnum ceremony, involving priests’ assistance in prayer and washing.   

The Torah outlines the need for believers to wash their hands and feet in ‘living water’, which can be in a sea, river, spring, or special bath called a mitveh, before approaching God. 

Hindu temples are built near a water source so that one can bathe before entering the place of worship, and carry out Sodhana purifications. Pilgrimage sites are often found on riverbanks, especially as the point where rivers converge is regarded as sacred. Water is involved in all ceremonies in Hinduism.

Water can sometimes not be such a prominent feature in Buddhist practices, as it is believed that ritual practices pose a distraction from the goal of spiritual enlightenment. However, yonchap are water offerings in Tibetan homes that can encourage one to give with an open heart. 

In Buddhist funerals, there is a tradition of pouring water into a bowl near the deceased, so that it overflows. Monks may recite the words: ‘As the rains fill the rivers and overflow into the ocean, so likewise may what is given here reach the departed.’

Sacred water sites

Many religions have bodies of water or related sites that are historically or spiritually significant, and can be popular sites for pilgrims to visit.

  • There are seven rivers in India that are considered sacred, and seen as maternal, life-giving female deities: Ganges, Yamuna, Godavari, Saraswati, Narmada, Sindhu and Kaveri. 
  • The most famous river is the Ganges, believed to be the most sacred river in India. Millions travel to the Ganges to wash, be cleansed and healed. Some Hindus see the Ganges as a crucial site of pilgrimage, and believe that a life is incomplete without bathing in the river at least once. Families often keep a vial of water from the Ganges in the home.
  • The Well of Zamzam is a site of pilgrimage in Mecca, Saudi Arabia, where Muslims go to drink the sacred water. It is believed that the well is a miracle source of water, which sprung up to quench the thirst of Ishmael, son of Abraham, thousands of years ago. The well lies 20m east of the Kaaba, the holiest place in Islam, and is visited as part of the Hajj or Umrah pilgrimages. 
  • Many Christians consider the Sea of Galilee to be a special place of pilgrimage, as this is the region around which Jesus’ ministry centred. The river Jordan is particularly visited as the site where Jesus baptised and was himself baptised by John.
  • Lake Titicaca in the Andes is a sacred site for Inca people as, according to ancient myths, the sun first emerged from this lake and blessed it.
  • Cenotes, or natural pits of water, are important in Mayan culture, thought to offer access to the watery underworld. Chichén Itzá is the most famous cenote, and one of the most visited archaeological sites in Mexico.

This is only a brief overview of the religious weight of water. There is much more to be said and gained from learning about how cultures revere water in diverse traditions.

Microbial fuel cells - The future of clean water?

Perhaps the biggest issue with water treatment plants is the amount of energy they use. On average, it takes 1.5 kilowatt-hours to remove even a kilogram of contaminant from polluted water. If you look at that in terms of water treatment on a national or international scale, it accounts for a huge chunk of energy demand. 

The solution is to make water treatment a self-sustaining process, and for the first time it looks like we might have found a way to do that. The name of the game is biotechnology; we already use engineered biological processes for food production, medicine and more recently fuel. We already know that biological processes can be manipulated to produce energy, so what if they could form a self-powering treatment system.

That’s exactly what Boston-based company Cambrian Innovation have done. In partnership with the US Army, they have developed ‘BioVolt’, a wastewater treatment system which generates the energy needed to power itself, with no electrical input necessary. The microbes themselves are electrically active, and they catalyse a fuel cell process which treats wastewater and generates electricity all at once. What’s more, a large facility isn’t needed to house such a system; it can be scaled down the point where you can carry it around in a portable container.

Img source:
So already this sounds pretty amazing, but there’s more. The BioVolt system is now being regarded as a blueprint for even more advanced developments in the near future. The active microbe strains in the BioVolt system are ‘Geobacter’ and ‘Shewanella’, both of them essentially consume pure energy, coaxed from rocks and metals. It stands to reason, all bacteria deal with the electrons present in sugars and other minerals, these ones just cut out the middle man, and in this way they can be grown directly on electrodes. 

The applications of this are widespread and exciting, already a larger pilot system for water treatment is being built in Tijuana, and this one will also be able to remove pharmaceutical waste from the water.

In either case, systems like these have the potential to clear tens of thousands of litres of contaminated water every day, and act as a kind of equivalent/counterpart to solar and wind energy. Moreover, any kind of biological system which requires energy to function could be considered for the BioVolt treatment, as microbes which consume pure energy could, in theory, carry on forever. 

Callum Davies

Callum is a film school graduate who is now making a name for himself as a journalist and content writer. His vices include flat whites and 90s hip-hop. 

Monday, 8 August 2016

Hydraulis: The water-powered keyboard

The water organ, also known as a hydraulis, is thought to be the world’s first keyboard instrument, and oldest pipe organ. The name ‘Hydraulis’ comes from the Greek for water, ‘hydra’, and pipe, ‘aulos’.

An engineer from the 3rd century BC, Ctesibius of Alexandria, is credited with its invention. It is highly unusual for us to know the name and identity of the inventor of such an ancient object, since for many instruments all that it known is that they were believed to have divine or mythical creators.

The ancient hydraulis was played by hand, and the sound was controlled by the player pressing lightly on balanced keys or sliders. This is in contrast to the Renaissance pipe organ, which played automatically with the flow of water.

The organ is driven by water, which enters a wind chamber (camera aeolis) from above through a pipe. Air is introduced via a side pipe, compressed and driven upwards into a wind trunk or chest. This is used to blow the pipes, while two diaphragms or ‘splash-plates’ shield the pipes from water spray.

In some designs, the water comes out of the wind chamber and powers a water wheel, which drives a cylinder. A tap above the instrument must be opened for the instrument to run, and it will continue to play until the tap is closed.

These diagrams show the workings of the hydraulis (via
The player would pump from point A, on the left diagram, forcing air through pipe D. Valves ensure the air does not flow backwards. The water pressure pushes air up through pipe J, and into the wind chest.

On the right, we see a close-up of a pipe. The player plays the key at A, which moves the glider C, allowing pressurised air to escape through the pipe when D and E align. F is a quill that dictates the end of the note by closing the gap.

The mechanics of water organs are discussed in various ancient sources: in writings by Ctesibius himself and Philo of Byzantium from the 3rd century BC; accounts by Vitruvius, a Roman engineer, architect and author of De Architectura, from around 20 AD; and those by Hero of Alexandria, from around the year 62 AD. 

Depictions of the instrument have been found in mosaics, paintings, as well as on coins, and even oil lamps. These have helped historians piece together what the hydraulis looked like, and when and where it might have been played.

These oil lamps were made in the shape of water organs, and can be found in museums at Copenhagen and Carthage today. (via

A coin featuring a water organ, dating from the time of Nero. (via

It appears the water organ was widely used for outdoor entertainment, at public events and festivals, probably because of the loud, deep sound it produces.

The mechanisms of the water organ were discovered with the help of partial remains, such as those found in Budapest in 1931, which were inscribed with the date 228 AD. Although most of the instrument had decomposed over time, the metal mechanism was still intact. From this, a working replica was built, which can be seen in the Aquincum Museum in Budapest today. The museum is named after the ancient ancestor of Budapest, a Roman city called Aquincum.

The reconstructed hydraulis in action (via
Another important relic was uncovered in 1992 by archaeologists in the Greek city of Dion, which was an ancient Macedonian city near Mount Olympus. They believe they have recovered fragments of a hydraulis from the 1st century BC. A working replica was completed by the European Cultural Centre of Delphi in 1999, which is on display in the Museum of Dion, along with the fragments.

The fragments of a first century BC water organ at the Museum of Dion. (via 
Very little is known about what kind of music was played on these ancient instruments, but it is amazing that the low, penetrating sound of the pipes can be recreated for us to hear thousands of years after its invention.

Friday, 5 August 2016

The six biggest freshwater fish in the world

There can be no doubt that the ocean is the place to look if you’re in the market for really, seriously big aquatic life. The level of diversity in freshwater doesn’t even come close to matching that of seas and oceans, it’s too confined of an environment, which is also why life rarely gets the chance to scale up in the same way, there’s no need. In fact, being whale-sized in lakes and rivers would be fatally impractical, as no mass food source exists there to sustain such bulk.

Despite this, you still get some pretty big fish, at least relative to human size. Crocs, alligators and hippos are still by far the largest freshwater species, but since they spend a significant contingent of their lives on dry land, they can’t really be counted (nor can giant mutated catfish, as above). Below that, you have a big, impressive list of fish, many of which are so big that their marine counterparts are almost all sharks.


Image Soure: wikipedia
This chunky, endearingly ugly blighter can only be found in the Amazon River basin. They can be over 3 metres long and weigh more than 180kg. That’s the same as some kinds of motorcycle. Their weird, tapered head might look like it’s a result of bumping into too many walls, but in actuality it’s an adaptation to help them breathe air from the surface, as the air in the water isn’t oxygenated enough for a fish this size to rely solely on gills. Sadly, this also means they need to stick close to the surface, making them a prime target for fishermen. Data on their population is vague, at best, but a ban on fishing them has been placed in Brazil and during their breeding season in Colombia.

Alligator Gar

Image Source:
As you can probably tell, the alligator gar gets its name from the long, flat, alligator-like snout it sports. This is because they are ambush hunters, taking water fowl and small mammals from the surface and dragging them under to finish the job. Much like its namesake, the alligator gar’s evolutionary design has been around for millions of years, and they are often regarded as living fossils. Their spiral valve digestive system is a prime example of this, as it’s also present in another kind of living fossil – sharks. Several attempts to cull gars off have been made over the years, as they like to eat a lot of the fish that sports fisherman favour, but more recently they have become a protected species. The largest found have been in the vicinity of 3 metres long.

Mekong Giant Catfish

Image Source: YouTube
Catfish are generally pretty bulky, but the Mekong giant catfish is so big that it’s actually become the stuff of legend. In Thai folklore, these 3 metre long fish are called Pla Buek, and the play a role in a traditional fishing season which has been going on for centuries, sacrifices and offering have to be made in their honour before the actual fishing can begin. More recently their population has been supplemented by artificial breeding, as they have become critically endangered. Fishing isn’t the only issue these 300kg monsters face; their migratory patterns have been heavily disrupted by dam building and other forms of construction, which has prevented them from breeding them effectively. It’s a terrible shame, they’re amazing creatures, their bodies are almost entirely coated with taste buds, allowing them to ‘taste’ their way through murky water.

Giant Freshwater Stingray

Image Source: Wired
Saltwater stingray can get pretty humongous, but they’ve got nothing on this guy. They can be more than 3 metres long or 2 metres across, but that’s not the most astounding part. Previous specimens have weighed in at up to or over 600kg. That’s more than half a tonne. Despite their massive size and weight, they weren’t formally identified by scientists until about 25 years ago, since they spend most of their lives skimming across the bottom of lakes and rivers in South East Asia. Along with their huge, flat bodies, the giant freshwater stringray also sports a 40cm long barb which is coated with a kind of venomous mucus which can pierce bone. Despite the fact that stingray meat is practically flavourless and woven with cartilage, it’s still considered something a delicacy, and so once again, fishing is a huge problem for these wonderful animals.

 White Sturgeon

Image Source:
While these fish can also live in the sea, these giant, white fish commonly spend much of their lives in freshwater, particularly when they spawn. I say commonly, there are only around 500 individuals left in the wild, which is all the more upsetting when you realise that, like the alligator gar, they are living fossils, unchanged for millennia. At their largest, they can reach a staggering 6 metres long, putting into the same running as thresher and hammerhead sharks. Their dwindling numbers largely owe to, you guessed it, overfishing. In the Bay Delta in San Francisco, about 750,000kg of white sturgeon was caught in 1887 alone, and by the early 20th century they were in major decline.

 Beluga Sturgeon

Image Source:

While the beluga sturgeon spends much of its life in brackish water, and will travel out to seas like the Caspian and Black Sea, it is still regarded as the largest freshwater fish by many. It can be in excess of 7 metres long, and weight a frankly terrifying 1,500kg, which is as much as a Volvo V70. It is one of the largest predatory fish on the planet, full stop, rivaling the Greenland shark and the tiger shark, but still dwarfed by the mighty great white. It mostly eats fish, but in a pinch it will go after waterfowl and seal pups. Amazingly, they can live for over a century, a result of the fact that they live life in the slow land, preferring to ambush their prey than pursue it. Their endangered status owes to their eggs being considered something of a delicacy, so if you’ve ever seen beluga caviar on a menu, you know where it came from.