It is hard to believe, particularly for people coming from dry and drought-ravaged regions of the planet (like our state of South Australia), that water covers more than 70% of the Earth’s crust. It is also the largest component of the human body, averaging around 60% of the body weight of an adult male although the proportion is even higher in a 20-25 week foetus (greater than 80%). All of our organs contain large amounts of water, and the myriad chemical reactions occurring in billions of cells in these organs taking place in an aqueous medium. The blood that carries nutrients to the different parts of our bodies is mainly water, and our waste products are dissolved in water ie urine. Just about everything we eat contains large amounts of water, and many of us drink a litre of more of water a day. So, however you look at it, water is central to our life.
Unfortunately, while we can’t do without water, the same applies to every other living thing on the planet, including bacteria, fungi, and parasites. Some of these grow and thrive in water, including bacteria that cause cholera and other diseases. Another property of water is its almost unique ability to dissolve all sorts of substances. Its ability to dissolve gases such as oxygen is absolutely fundamental to the survival of fish in the sea and rivers. Similarly, carbon dioxide dissolved in water is essential for the survival of algae and other plant life that live in the oceans, rivers and lakes.
But, of course, it is not just gases that dissolve in water. The oceans contain large amounts of salts as well as many other materials while the rivers, a major source of drinking water for many people, contain all manner of dissolved salts as well as sediment derived from rocks and soil. Fertilizers, animal wastes, composts, pesticides, industrial waste, pharmaceuticals, antibiotics used in animal feeds, plastic components, and air pollutants all find their way into rivers and, eventually, into the ocean. Traces of some of these materials, termed “organic matter” because the molecules it contains, are mostly made up of carbon atoms, may be present in our drinking water. The amount of this organic material in our drinking water is not insignificant because levels approaching, or even exceeding, 4 milligrams per liter are not unusual. This means that, over a fifty year period, and assuming we drink one litre (around 1.6 pints) per day, we take in over 70 grams (2.5 ozs) of this material.
Because of concerns about the possible presence of disease-causing microorganisms, our drinking water is almost always chemically treated in some way. There is no doubt that the chemical treatment, mostly with chlorine containing substances, is highly effective because bacterial counts in treated water are very low. However, the treatment is not without its own problems, because the chlorine-containing agents used have the capacity to interact with the organic material to produce a diverse array of chemicals which have been termed disinfection byproducts (DBP). Because of the complex nature of the organic material in water, and the fact that its composition probably varies according to the source of the “raw water” used for chlorination, there are potentially hundreds of DBPs, some of which have been identified and believed to be potentially harmful (1,2). There are suggestions that DBPs may increase the risk of certain cancers, such as bladder cancer, and may affect growth of the foetus in the uterus (3,4).
The often unpleasant taste of chlorinated water, combined with the perception that disinfection may produce harmful substances, and the fact that water purification processes may be inadequate, most notably in some developing countries, has led to an increase in consumption of bottled water, almost always in plastic. There is a belief that, because it is in a bottle, it is safe to drink. Quite apart from the environmental contamination caused by the billions of slow-to-degrade plastic bottles and the gradual release of plastic components into the soil and water, there is now evidence that water in plastic bottles can contain substances that can move from the container into the water (5). Some of these substances have estrogen-like activity ie they mimic the effects of the female sex hormones and therefore have the potential to affect growth and development (6). Bisphenol A, a plastic component believed to affect the brain, behaviour and the development of the prostate, has also been found to migrate from plastic bottles into water (7) (and discussed in the most recent Promoting Good Health blog “Plastic – not so inert and harmless after all”).
What does all of this mean? Well, it does mean that, as with any technology, and water treatment is no exception, there are costs as well as benefits. Clearly the treatment of water does greatly reduce the risk of infections and this is a major benefit. However, the increasing pollution of rivers and water catchment areas with the many waste products of human activities, in combination with the treatment methods employed, results in the production of a variety of chemical substances, some of which may increase our risk of non-infectious diseases like cancer.
Promoting Good Health has long had concerns about the impact of environmental pollutants, including those formed by chlorination of water. Our book, “The Silent Threat”, available for purchase through this website, describes in some detail why water is chlorinated, the nature of the substances produced, their potential impact on your health, and how you can reduce your exposure. It also discusses information on the quality of tank and bottled water.
Until next time, stay happy and healthy!
(1) Hrudey S. E. (2009) “Chlorination disinfection by-products, public health risk tradeoffs and me.“. Water Res., 43 (8), 2057-2092.
Abstract available online at: http://www.ncbi.nlm.nih.gov/pubmed/19304309 
(2) Pressman J. G., et al (2010) “Concentration, chlorination, and chemical analysis of drinking water for disinfection byproduct mixtures health effects research: U.S. EPA’s Four Lab Study.” Environ. Sci. Technol.; 44, 7184-7192.
Abstract available online at: http://www.ncbi.nlm.nih.gov/pubmed/20496936 
(3) Nieuwenhuijsen M. J., et al (2009) “Health impacts of long-term exposure to disinfection by-products in drinking water in Europe: HIWATE” J. Water Health, 7(2), 185-207.
Abstract available online at: http://www.ncbi.nlm.nih.gov/pubmed/19240347 
(4) Tardiff R. G., et al (2006) “Updated weight of evidence for an association between adverse reproductive and developmental effects and exposure to disinfection by-products.” Regul. Toxicol. Pharmal.; 45 (2), 185-205.
Abstract available online at: http://www.ncbi.nlm.nih.gov/pubmed/16624462 
(5) Matsuga M., et al (2006) “Migration of formaldehyde and acetaldehyde into mineral water in polyethylene terephthalate (PET) bottles.” Food Addit. Contam.; 23 (2), 212-218.
Abstract available online at: http://www.ncbi.nlm.nih.gov/pubmed/16449065 
(6) Wagner M. and Oehlmann J., (2010) “ Endocrine disruptors in bottled mineral water: Estrogenic activity in the E-Screen.” J. Steroid Biochem. Mol. Biol.; November 2 [Epub ahead of print).
Abstract available online at: http://www.ncbi.nlm.nih.gov/pubmed/21050888 
(7) Le H. H., et al (2008) “Bisphenol A is released from polycarbonate drinking bottles and mimics the neurotoxic actions of estrogen in developing cerebellar neurons.” Toxicol. Lett.; 176 (2), 149-156.
Abstract available online at: http://www.ncbi.nlm.nih.gov/pubmed/18155859 
Full article available at: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2254523/pdf/nihms-38737.pdf