“Welcome to our *ool.”
(Noticed the absence of “P” in it? Consider “P” officially banished from the pool-water!)
Since I was a kid, this was the ubiquitous message I often came across nailed to a nearby fence, wall or the toilet door next to the swimming pools wherever I went. A plea to keep the germs out, to keep the pristine, chlorinated pool water sparkling clean. To keep it free of PEE and POO…
Is our pristine pool water really clean?
It’s pool season, the grandest of all seasons, or so you might think. Other than becoming a most sought-after place for a recreational cool off on warm days, jumping in the pool also helps you stay in shape. Being a non-weight-bearing exercise, swimming utilises most of your muscles, making it effective for both cardio and muscle endurance.
However, public swimming pools are a “lavish bowl” of health risks that can infect you and your family. According to a report from the Centres for Disease Control and Prevention (CDC), 493 recreational waterborne disease outbreaks were reported from 2000 to 2014, causing at least 27,219 illnesses; almost one third of the total number. Most of them were traced back to hotel swimming pools or hot tubs. The numbers are still multiplying exponentially.
Germs, germs, germs
Humans aren’t the only creatures that visit swimming pools. Just like us, the germs that enjoy hanging out in the recreational water come in all shapes and sizes. These include various pathogens such as viruses (hepatitis A and norovirus), bacteria (Shigella species; the nasty E. coli) and parasites (Cryptosporidium and Giardia). Most of these can cause a range of gastric symptoms, such as diarrhoea, nausea, vomiting or stomach cramps.
Swimmers are at risk of respiratory infections if they breathe in steam or mist from a pool that contains the harmful bacteria, Legionella. It results in flu-like symptoms and can put you at risk of Legionnaires’ disease – a severe pneumonia that would probably put a damper on the rest of your summer.
Infection with the bacterium Pseudomonas or certain fungi can result in skin rashes (dermatitis, folliculitis or athlete’s foot) or swimmer’s ear (otitis externa) – an infection in the outer ear canal that can cause pain and discomfort for swimmers.
How do they get into the water?
Obviously not by leaping from the diving board or clambering down the poolside ladder. They get into the pool by hitching a ride on us. Many of these germs spread from person to person in swimming pool water via faecal transmission – meaning, by swallowing water that’s had poo in it.
These bugs live and multiply happily in an infected person’s gastrointestinal tract and are excreted in their poo. Surprisingly, there is actually a small amount of poo on most people’s bottoms – about 0.14 grams of faeces on average, according to the CDC. This poo can get washed from their skin into the water, and the contaminated water is then swallowed by other swimmers, transferring the germs to their bodies. More dramatically, a baby or toddler might poo in the water (an accidental faecal release, or AFR), releasing a gush of bugs into the water, small amounts of which may then be swallowed by other swimmers.
In case you believe that you don’t swallow the water when you swim, a 2006 study found that, during a 45-minute swim, adults swallowed, on average, 37 millilitres – that’s almost two tablespoons. Children swallowed twice as much. Once swallowed, germs live in their new host’s gastrointestinal tract until they’re pooed out, beginning a new cycle again.
The hard-to-kill: Cryptosporidium and Giardia
If all this has you swearing never to go in a swimming pool again, don’t worry. Viruses and bacteria are controlled by proper, regular disinfection regimes, including chlorination. Of course, if there’s been an ‘AFR’ (or if someone has vomited in the water), normal disinfectants won’t be enough to keep germs under control. The contaminated area may need an extra dose of chlorine; the pool may need to be emptied, disinfected, and refilled; or the whole pool may need to be closed and superchlorinated/given a shot of ultraviolet radiation/ozone.
Nevertheless, two bugs that are fairly resistant to pool chemicals (thanks to their hard outer shells) are the single-celled parasites Cryptosporidium and Giardia, the leading cause of pool-related infestations. They’re found in the faecal matter of fellow swimmers who are infected, and the spores can survive for days to weeks or even months in water. If you’re unfortunate enough to swallow the water contaminated with either, you may experience a range of symptoms, including acute diarrhoea, bloating, fever, nausea, and vomiting for as long as two to three weeks. It can be particularly dangerous, even fatal, in children, pregnant women, or people with a compromised immune system who are undergoing chemotherapy or have AIDS/HIV.
Cryptosporidium, in particular, is highly infectious. Just one person infected with Crypto can pass enough germs to contaminate a large pool, and you don’t need to swallow much of the contaminated water to fall sick. (To put some numbers on it, an infected person can shed up to 100 million Cryptosporidium germs in one bowel movement, and you only have to swallow 10 germs to get sick).
Worried about wee?
One out of every five people going for a swim pees in the pool, says a survey conducted by the Water Quality and Health Council. It is known to contain bacteria. The levels are higher in people with urinary tract infections, which are fairly common.
Although it’s unlikely you’ll get sick from swimming pool water that’s had wee in it, as the bacteria in urine are likely to be tackled by chlorination. However, pee in your pool can cause other problems, which, in turn, can allow bugs to flourish. When ammonia in urine reacts with chlorine, free chlorine is consumed, releasing chemical irritants, chloramines. Not only do chloramines reduce chlorine’s effectiveness, but they can also make us sneeze, sniffle and cough. If you’ve ever found yourself with streaming eyes or a runny nose at the pool, chloramines are probably the reason.
The strong smell which you might encounter at some pools and think of as ‘chloriney’ (germ-busting) is actually not the smell of chlorine, but of chloramines. It’s a sign that there’s a fair amount of muck (urine or sweat) going into that pool.
Is chlorine enough to keep our swimming pools safe?
The unhealthy behaviour of pool-goers has put swimmers at a whopping risk of developing recreational water illnesses (RWI). Poor practice of pool compliance, such as the lack of maintaining appropriate disinfectant and pH levels, makes swimmers, especially kids, sick.
To help protect swimmers from pathogens, proper pool maintenance is essential.
# Chlorine is the most sought-after disinfectant used to keep bacteria and viruses at bay. (Click here to know how). However, opposed to the popular belief that chlorine kills germs instantly, it actually takes varying intervals for the same amount of chlorine to work on different microorganisms.
- It will kill bacteria such as E. coli in under a minute, but it may take around 16 minutes to kill the hepatitis A virus.
- It’ll need 45 minutes to kill Giardia, and (wait for it) up to 10 days to kill Cryptosporidium.
Appropriate levels of chlorine are equally important. While a higher concentration can get you an itchy rash, make your hair dry and brittle or give you red, itchy eyes, lesser amounts would be just not sufficient.
# Pathogenic microorganisms can also be inactivated by other chemicals, such as bromides, or physical filtration methods, such as treatment with UV radiation or ozone systems.
# It’s important to get the water’s pH level right (how acidic or alkaline). It determines how effective chlorine is in killing germs. While a higher pH makes the disinfection less effective, a very low pH can corrode the swimming pool’s pipes. A water pH between 7.2 and 7.8 is just perfect. A level higher/lower than the mentioned range can irritate your eyes and skin.
If you have your own pool, you have a responsibility to maintain it so that it does not present a health hazard to those enjoying a splash.
How to avoid getting sick after a dip?
- Swim only in well-maintained pools with clean surfaces devoid of any slimy biofilms, where pathogens like Legionella and Pseudomonas can flourish.
- It’s also important to check facilities’ functional filtration systems, inspection scores, ask facility operators about their maintenance practices, and avoid facilities that aren’t properly maintained.
- The most important thing is to be sure the pool is chlorinated. If you do not smell chlorine, do not get into the pool. A crowded pool means more chlorine is needed to maintain safe water chemistry. Try to go swimming in the morning and evening, when the pool is not too crowded. To help protect swimmers, facility operators should check chlorine levels regularly, especially when the facility is busy.
- Avoid swallowing water from pools and other recreational facilities.
- Avoid swimming while sick.
- Stay out of the water for at least two weeks after the disappearance of symptoms if you had a gastrointestinal infection or diarrhoea.
- Take small children for frequent loo breaks when using the pool.
- Use swim nappies for babies who are going in the pool, and change often (in the change room, not poolside).
- Use the toilet before getting inside the pool and never pee in the water.
- Have a shower before going into the pool to make sure you wash off any dirt, excess bacteria, or even skin oils and suntan lotion, which can tie up the chlorine that’s used in pools to kill the germs. (Wearing sunscreen in the pool can actually bind the chlorine to your sunscreen, making it unavailable to kill the germs.)
- Wear a swim cap while in the water.
Dr Renu Madan 