Wednesday, 8 April 2015

Do you know what is in the water you swim in?

            Do you go swimming often? Would you want to swim in a green pool?!  Do you know what keeps the water so crystal clear and sparkly? CHEMICALS!

What chemicals? 

            The main component of most pool cleaners is calcium hypochlorite, as it comprises approximately 50-70% of commercial pool sanitation products [1,2]. This product typically appears white and comes in a solid brick or powder form to be added to your pool [3].

How does it work?

 It is mixed with other chemicals such as calcium chloride and lime and when this mixture comes into contact with water it breaks apart and forms hypochlorous acid [4]. This acid is known as a disinfectant, which has the ability to kill the microorganisms that are living in the water [4].

Is it safe for humans if it kills microorganisms?   

There is scientific evidence that suggests there is no link between calcium hypochlorite and cancer. In studies, mice and rats have been exposed to the chemical both by ingestion and direct contact with their skin. In both cases, the mice and rats all survived and showed no signs of tumors [1]. However, even though calcium hypochlorite does not cause cancer it can be toxic to humans when it is in high enough concentrations and is in its pure, solid form. It can cause chemical burns to skin and eyes, irritation and vomiting when ingested and can lead to olfactory fatigue when it is inhaled [5]. Olfactory fatigue is when an individual can no longer smell the chemical when they are exposed to it [5]. 

Other concerns?

            The major concern when it comes to calcium hypochlorite is that in its pure, solid form it is a very strong oxidizing agent and can cause explosions [3]. To prevent this it is important to store calcium hypochlorite in dry, cool areas, in a tightly sealed container and away from things like oils and soap [3].


            If you are worried about using calcium hypochlorite there are other ways to clean your pool. A chemical alternative is sodium hypochlorite, which acts similar to calcium hypochlorite [3]. A non-chemical alternative is an ultra-violet system that uses strong beams of light to kill the microorganisms in the pool [3].

            Overall, when calcium hypochlorite is handled and used properly it only causes harm to the microorganisms living in your pool and not to humans since it is not at high enough concentrations.


[1] - International Agency for Research on Cancer. (n.d.). Hypochlorite salts. Retrieved March 24, 2015 from

[2] - Spellman, F.R. (2009). Handbook of Water and Wastewater Treatment Plant Operations, Second Edition. Taylor & Francis Group, LLC.

[3] - Human Kinetics. (2008). AquaTech: Best Practices for Pool and Aquatic Facility Operators. Human Kinetics, Inc.

[4] - Virginia’s Community Colleges. (n.d.). Chlorination chemistry. Retrieved March 31, 2015, from

[5] - Agency for Toxic Substances & Disease Registry. (2014). Medical management guidelines for calcium hypochlorite. Retrieved March 29, 2015, from

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