By David Knighton MD

Co-Founder and CEO of Creative Water Solutions and PoolNaturally^® Plus

Introduction

Walk into a building with a pool and you can instantly tell it’s there by the smell.  No matter how big the building, small the pool, or robust the heating and ventilation system, that characteristic “chlorine” smell is there.  If you are like me, a few minutes of exposure to the smell will bring tightness to my chest, itching to my eyes, and after about 20 minutes a light headed feeling.  Go outside and it all goes away in about an hour.  Swim and it can take days to return to normal.  Competitively swim or swim daily and you probably get so used to the air you become acclimated to the irritation of disinfection byproducts (DBP).  In the past few years, a lot of research has defined what causes this smell, what effect it has on swimmers, and what can change the creation of DBP’s so the pool becomes a “you don’t know there is a pool until you see it” experience.  

How are DBP’s formed?

 DBP’s are formed when chlorine, bromine or any halide molecule used to kill bacteria in the water, combines with biologic molecules that contain carbon and nitrogen.  The most prevalent molecule in the swimming environment is urea from urine and sweat.  Urea undergoes chemical changes in the pool and combines with chlorine or bromine to form over 30 different DBP’s.  Some of these molecules stay in the water and others are volatile so they diffuse into the air above the water and eventually into the entire building.  The act of swimming actually increases the concentration of DBP’s by churning up the water and increasing the concentration of these molecules in the air. 

What Effects do DBP’s have on people?

We know a lot about the effect of one DBP – chloroform – since it was the most commonly used anesthetic for decades.  The fancy name for this class of DBP is trihalo-methane (THM).  There are many different THM’s with different effects on people, just like there are many different types of DBP’s that have different effects on people.  We will look at chloroform and trichloronitrate.

Chloroform inhaled at a concentration of 10,000 ppm puts you to sleep.  Prolonged exposure at this very high level will kill your liver, depress your heart function and kill you.  In human volunteers, exposure to 4,100 ppm causes serious disorientation and 1,000 ppm causes dizziness, nausea, fatigue and headaches.  Prolonged exposure to as little as 10 to 200 ppm can cause liver enlargement and effects on the central nervous system.  For a reference, we have measured THM concentrations in commercial indoor pools in the 2 – 3 ppm range. 

Application of chloroform to the skin causes redness of the eyes and itching of the skin.  One study of people exposed to low levels of chloroform in their drinking water showed a correlation between chloroform concentration and rectal and bladder cancer.  In fact, an international health agency classifies chloroform as a carcinogen for humans.

Other studies, especially from Europe, document the effect of trichloronitrate on swimmers.  They conclude that this DBP is related to reactive airway disease or asthma in people who swim frequently.  Another study shows that DBP’s are associated with changes in DNA in urinary bladder cells that correlate with an increased risk of cancer.

To summarize, DBP’s not only smell bad, they irritate your skin, eyes and lungs; cause central nervous system changes such as dizziness and headaches; cause fatigue; and with prolonged exposure are potential carcinogens.

How do DBP’s affect swimming performance?

Any athletic performance is determined by muscle contraction.  Muscle contraction is an energy consuming activity that is related to oxygenation of the blood and blood flow to and from the contracting muscle.  Oxygen is used along with blood delivered nutrients to produce energy so the muscle cells can contract and propel the swimmer through the water.  Oxygen is delivered to the blood through the lungs as we breathe.  Oxygen is then carried by our red blood cells to all tissues in our body including muscles, by blood flow.  Blood flow depends on our heart to pump the blood and arteries to carry that blood to our exercising muscles.

At rest, our muscles require very little blood flow and oxygen.  As we start to exercise and use our muscles to propel us through the water, they consume all the oxygen and nutrients in the area, then tell their arteries to dilate and send more blood.  That causes our hearts to beat faster to supply more blood for the dilated arteries and that eventually causes us to breathe faster to deliver more oxygen to our lungs.  A big part of athletic training, is to maximize this energy transport system from air to muscles.  The more we exercise, the better the system works.  The better the system works, the more we can exercise.

DBP’s affect performance in a number of ways.  First, the air just above the water is what a swimmer inhales during swimming.  That air has the highest concentration of DBP’s.  The amount of oxygen in air follows the rules of physics.  The higher the concentration of DBP’s, the fewer oxygen atoms in the same amount of air.  So the swimmer in a pool with high DBP’s needs to move more air in and out of their lungs to remove the same amount of oxygen as a swimmer in a pool with lower DBP’s.

DBP’s like trichloronitrate cause lung irritation and narrowing of the tubes that bring air into our lungs.  Because of the narrowing, less oxygen gets to the microscopic areas of our lungs where the delivery of oxygen to the blood occurs.  Therefore, we need to move more air to extract enough oxygen for our exercising muscles.  One result of this lung irritation is the use of drugs, called bronchodilators, that open up the airways and others, that control the inflammation caused by the irritating DBP’s.  This asthma is a significant problem in many competitive swimmers.

Like most diseases, some people are more sensitive to DBP’s than others. 
Those swimmers who are sensitive to DBP’s have to work harder to provide adequate energy for their contracting muscles than those who are less sensitive to DBP’s irritation.

Performance and conditioning is all about maximizing oxygen extraction from the air, blood flow to the muscles, and removal of waste products from the exercising muscle.  DBP’s play a significant role in oxygen concentration in the air; delivery of air to the blood, and pumping of blood to the muscles.  Along with the other health effects of chronic exposure to DBP’s and the uncomfortable irritation they cause, swimmers should do everything possible to minimize the concentration of DBP’s in their pools.

What can swimmers do?

Since urea is one source of nitrogen containing bio-molecules that form DBP’s, swimmers can reduce their formation by not urinating in the pool.  Sweat is another source of urea that cannot be easily controlled since training causes increased sweating.  I’ve talked to many competitive swimmers who tell me they don’t want to stop their training to go to the bathroom to urinate or that their coaches won’t let them take a break.  Changing this would help create a more healthful environment for every swimmer, coach, lifeguard, and spectator.

What can facilities can do?

Ventilation

To understand the role of ventilation in this problem, we need to remember that DBP’s are at their highest concentration on the surface of the water.  This is the boundary layer where there is little air movement.  Traditional ventilation brings outside air inside, warms it up or cools it off depending on the temperature, and then moves it through the building, eventually pushing the air back outside.  This is a very expensive process.  Moving more air from the outside and through the entire space of the natatorium doesn’t address the area of the pool where DBP’s are in their highest concentration.  Increasing the air movement at the surface of the pool does result in a decrease in the concentration of DBP’s.  Paddock Evacuator Company’s Chloramine Evacuation System achieves this by a system that moves the air across the boundary layer and moves it outside.

Water treatment

Water disinfection and formation of DBP’s is a classic “rock and a hard place” situation.  Chlorine and bromine are very effective and efficient killers of swimming (planktonic) bacteria and algae.  They accomplish this through their chemistry.  They are very reactive with other atoms and molecules.  This reactivity oxidizes proteins and sugars in the cell wall of bacteria and algae, but also reacts with carbon and nitrogen containing compounds to form DBP’s in the water and air.   It is the main way we control bacterial growth in most water systems.  Even treatment systems, such as salt pools, control bacterial growth with chlorine.  You don’t have to add the chemical, a reactor in the pool creates bio-reactive chlorine from the chloride ion in common salt.

When we started treating commercial pool water with PoolNaturally^® Plus we found that the air quality in the pool area improved in a couple of days and the air in the entire facility was significantly improved after a week of treatment.  Over time our customers starting saying that the only way you know there is a pool in the building is to see the water.  Swimmers, coaches, lifeguards, and pool patrons all reported less eye, skin, hair, and lung irritation.  After a swim meet in one of our pools, many swimming teams demanded that their facility add PoolNaturally^® Plus.

To measure the effect of PoolNaturally^® Plus on DBP concentration, we did a study with a fitness club to measure the THM in the air above the pool surface and the water in their two indoor pools (75,000 and 86,000 gallons).  We measured levels weekly, for two weeks before PoolNaturally^® Plus was introduced and then about every other week for 33 weeks. They have a high bather load and use chlorine for disinfection.  We measured a steep decline of THM in the water resulting in 75% reduction in 33 weeks.  In the air above the pool the chloroform concentration was decreased by 55%.  The air quality improved just like in our other indoor facilities.

How does PoolNaturally^® Plus affect DBP production?

The quick answer is we don’t know.  We do have a hypothesis.  PoolNaturally^® Plus is made from Sphagnum moss leaves.  In our laboratory, over the past 8 years, we have shown that PoolNaturally^® Plus inhibits biofilm formation.  Biofilm is a slime like substance that protects bacteria that adhere to the pool or filter surface.  In fact, most bacteria prefer to adhere to a surface and cover themselves in biofilm, than to swim unprotected in the water where chlorine can kill them.  We think the unique environment inside the biofilm helps convert urea and other organic compounds into DBP’s.  We postulate that inhibiting biofilm reduces the production of DBP.  The product could also have a direct effect on the DBP produced in the pool.  We know the concentration is significantly decreased.  We don’t quite yet know how.

PoolNaturally^® Plus and swimming performance

We know competitive swimmers like training in water conditioned with PoolNaturally^® Plus.  We know that swimmers with asthma report that they don’t use their inhalers when they swim in outdoor or indoor pools where water is treated with PoolNaturally^® Plus.  We also know that lifeguards and aquatic professionals report fewer respiratory problems working around pools with PoolNaturally^® Plus.  We don’t know if their training and eventual performance is improved, and it will take time and study to know if the reactive airway disease, DNA changes and other health effects of DBP’s are improved.

Summary

1. Use of chlorine and bromine as disinfectants in pools produces disinfection byproducts that have significant health and performance effects.
2. DBP’s, such as chloroform, other THMs and trihalonitrates irritate people’s eyes, skin, lungs, and central nervous system.
3. Pool water conditioned with PoolNaturally^® Plus reduces the “chlorine smell” in treated pools and resulted in a 75% decrease in THM in commercial pool water and 55% reduction in natatorium air.
4. Patrons of pools treated with PoolNaturally^® Plus report significantly less eye, skin and lung irritation.

References

Articles about asthma and chlorine:

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1747493/

http://www.pslgroup.com/dg/2076de.htm

http://www.erj.ersjournals.com/cgi/content/abstract/19/5/827

http://swimming.about.com/od/allergyandasthma/a/cl_pool_problem.htm

http://findarticles.com/p/articles/mi_m0CYP/is_13_111/ai_111200649/

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1626429/

Chloroform and effects on humans:

http://www.osha.gov/SLTC/healthguidelines/chloroform/recognition.html

THMs and bladder and colorectal cancer:

http://www.biomedcentral.com/content/pdf/1477-3163-3-2.pdf

More about Paddock Evacuator Company’s Chloramine Evacuation System:

http://www.paddockevacuator.com/about_evacuator.html

More about Creative Water Solutions’ PoolNaturally^® Plus system:

http://www.cwsnaturally.com/commercial.php

Anyone who owns, cares for, or cares about pools, spas or any kind of recreational water, knows that water filtration is an integral part of every water system.  Using sand for filtration is commonly used on recreational and residential pools and large spas.  Here are some of my observations, thoughts and concerns about sand filtration.

The Good

Sand is cheap, plentiful, and when it is a particle, it works well as a filter medium.

The Bad

Sand filters are usually filled, sealed and the sand is forgotten.  The commonly held belief is that back washing the sand periodically, “fluffs it up” and returns the sand to a particle state where it can again work its magic as a particulate filter.  Some sand filters have never been opened for 5-10 years to inspect the sand.

Back-washing the sand filter is costly.  Water lost during back washing needs to be replaced, heated and treated.  Ideally, the pool operators backwash often enough to keep the sand working as a filter, but do not needlessly back wash so water, heat, chemicals and time aren’t wasted.

The Ugly

Inspecting and analyzing the sand from pool sand filters in both residential and commercial pools has been enlightening, to say the least.  At the bottom and sides of many filters we found sandstone.  Actual sand in the process of forming sandstone. It wasn’t the gravel that is often put down underneath the sand, but sandstone.  The sand in those filters was anywhere from 2-10 years old.  The sand that wasn’t rock was sticky and foul.  When we tested it in our laboratory, we found that it was full of biofilm.

The Hypothesis

We know that in an aqueous environment that contains bacteria, biofilm forms on every surface.  To be effective, filters have enormous surface area whether they are made from sand, charcoal, paper, glass or diatomaceous earth.  The particles become covered with biofilm over time.  Biofilm is very sticky so the particles stick together.  As time and pressure continue to pack the biofilm-coated particles together they eventually become rock.  So what happens during backwashing?  The water will take the path of least resistance.  We observed in these filters that there were channels in the sand.  We think that the water follows channels through the sand that have become established over time.

We know that backwashing will not remove biofilm.  In fact there are very few things that will remove biofilm.  Strong acid or base solutions work but they destroy the filter, pumps, valves etc.  We have demonstrated that a flush used in spas removes 90% of laboratory created biofilm in one hour, and that many other solutions that claim to remove biofilm don’t.

Getting Better Results

We also have observed that sand in filters where the water is treated with PoolNaturally^® Plus (the commercial version of the residential product PoolNaturally^®) appears to remain as particles.  We think this is why we needed to backwash filters with PoolNaturally Plus much less often than those with conventional water treatment.

By understanding the relationship between biofilm, filters and water we are aiming to create biofilm free aquatic systems that require less chemicals, maintenance, and unwanted side effects.

Remember – biofilm forms when bacteria in solution adhere to a surface, divide and cover themselves with a protective layer of slime (mucopolysaccaride).  Learn more at Montana State University’s CBE site.

You could try to completely sterilize your spa and the spa water and keep it sterile; drain the spa and use fresh water every week; use a flush to remove all biofilm once or twice a month and replace the water; OR you can prevent formation of biofilm while killing all swimming bacteria.  Let’s look at each one.

The Hard Way:

Sterilize your spa and water

There is no easy way to sterilize every surface in your spa short of sending it to an industrial sterilization facility that uses high power x- rays.   Even if that was done, the water placed into the spa would have to be sterilized, and you couldn’t use the spa because the second you stepped into the spa the bacteria on your skin would quickly repopulate the spa water and the spa surface.  In my research laboratory, we conduct many experiments under sterile conditions and keep the systems sterile.  The amount of work and equipment in addition to training required to accomplish that is enormous.

Drain the spa and use fresh water every week

This is essentially how commercial spa operators try to keep their spas within health department guidelines.  They often use a measurement called “total dissolved solids” to determine when to dump the water and start fresh.  Depending on the bather load, this could be done twice a week or weekly.  The water is then treated with a sanitizer like chlorine to keep the bacteria count in the water within safe limits.  This approach uses a lot of water, takes a lot of time, and does nothing to address the formation of biofilm in the spa.  With the biofilm present in the spa, any excess bacterial challenge or change in bather load will “tip the balance” of the water and require more frequent water changes.

Use a flush to remove all biofilm once or twice a month and replace the water

As we discussed in my last blog (September 23, 2009), we now have an effective flush system that efficiently remove biofilm from surfaces and keeps it in solution.  When the spa is drained, the biofilm goes out with the water.  With fresh water and sanitizer in the spa, new biofilm will form over time requiring reflushing and fresh water.  Theoretically, the water should last longer between changes than the previous scenario, but with frequent spa use, flushing would have to be done once or twice a month.  The same problems as above make this treatment plan a real problem.

The Easy Way:

Prevent the formation of biofilm and control the number of swimming bacteria

This solution is ideal.  Up until the discovery that certain species of moss prevent the formation of biofilm, this was a just a theoretical possibility.  We know that sanitizers like chlorine and bromine are very effective killers of bacteria that swim.  We now know that these same sanitizers are absorbed by biofilm and fail to kill all the bacteria within the biofilm.

Here’s how we now think this works: Combining the moss with sanitizer solves the problem.  The moss prevents biofilm from forming, allowing the sanitizers to efficiently do their work on planktonic (swimming) bacteria.  The moss also inhibits bacteria from dividing, so there are fewer swimming bacteria to kill.  Combined with the moss’s ability to remove heavy metals from water and stabilize pH, the spa water becomes stable, clean, clear and safe.  See the video on our website for more information about biofilm and moss.

Biofilm: A Slime City

A recent article in the July/August 2009 issue of Discover by Wendy Orent called “Slime City” talked about biofilm and its impact on medicine and implanted medical devices.  She did a great job describing what is known about biofilm and how it causes serious diseases and problems in the body. View the article:  http://discovermagazine.com/2009/jul-aug/17-slime-city-germs-talk-each-other-plan-attacks/?searchterm=Slime

The same biofilm that coats medical devices, your teeth, or an infected bone or wound covers every surface of your pool or spa.  All disinfectants such as chlorine, bromine, ozone, cooper or silver are effective killers of bacteria that swim in the water.  Unfortunately, that’s only 1-2% of the bacteria that populate a pool or spa.  The rest are safely protected from the disinfectants by biofilm.

The colony in biofilm is static.  It is alive just like a city.  The bacteria move, send off microscopic streamers of biofilm containing bacteria to settle on other surfaces, send off microscopic balls of biofilm to roll along the surface to start a new colony, and provide a nursery for bacteria to multiply and replace those that die off.

A Slime City in your pool or spa?

You see the effects of the biofilm streamers when your spa forms foam on the surface of the water.  Biofilm free water in a spa doesn’t foam.  The air bubbles injected into the water from the jets come to the surface and pop.  Biofilm in pools and spas cause the rings and scale on the pool sides.  It also causes cloudy water.

Recently, the scientists at the Center for Biofilm Engineering at Montana State University (http://www.erc.montana.edu/) discovered that biofilm causes corrosion of metals.  At the interface of the metal surface and the biofilm the pH is around 1 and there is a small electrical current produced by the bacteria.  The combination can cause electrolysis of almost all metals.

Think of your spa or pool’s heater cores, motors, seals and metal fittings.  The microscopic biofilm is slowly eating the metal causing mechanical failures that are costly to replace.

The take home message is that biofilm is a major contributor and cause of most problems in pools and spas.  So, how do you get rid of it? Tune in next week for more.

I was in Ferkessedougou, Ivory Coast working at a mission station for the summer between my sophomore and junior year of college.  I spent part of my time doing maintenance and the other helping with surgery.  I remember listening to the short wave radio as we heard Voice of America describe the landing.  It was night and there was a bright African full moon.  After they landed I went outside and looked at the moon marveling at the advances in technology that allowed that human footprint on the lunar surface.

The next morning I excitedly told my co-worker, in my broken French, what happened the night before.  He asked me “How long did it take them to get there?”  “Three days was my answer.”  He thought a while and then said, “The moon is as far away as Buoake.”  Buoake is a three-day walk from the mission station.

His frame of reference was completely different than mine and in a way both were accurate.

A Different Understanding

That experience is very similar to what is happening in the understanding of how bacteria live in pools and spas.  The old, accepted model says that bacteria like to swim and remain suspended in the water.  We now know that 99% of bacteria in water swim to the nearest surface, attach themselves, and set up a microscopic colony that is protected by a layer of sticky protein and sugar molecules we call biofilm.

The biofilm protects the bacteria from chlorine or other chemicals put into the pool to control bacteria.  In fact it absorbs chlorine, bromine or ozone so a lot has to be added to the pool to maintain proper levels.  As we study biofilm in our laboratory and more fully understand how it affects pools, spas and any other system where water, bacteria and a surface are present, we are convinced that most of the water problems plaguing the recreational water experience are due to biofilm.

The bad news is that bacteria protect themselves with biofilm and that all the chlorine, bromine, ozone, cooper, silver, UV light or other systems that only affect bacteria suspended in water are totally ineffective against bacteria protected with biofilm.  The good news is that we are discovering that the sphagnum moss in SpaNaturally and PoolNaturally may be nature’s answer to controlling biofilm.

While this research may not compare with the accomplishment of Apollo 11, in the future we’ll know that cleaner, safer water with fewer chemicals was a dream fulfilled through the scientific effort of hundreds of scientists who transformed our understanding of how bacteria live and protect themselves.