|MadSci Network: Environment & Ecology|
That's a very clever question Christine and one that, as you have found out by searching yourself, is not so easily answered. Experts all over the world claim both sides of the argument. In its natural form Chlorine is a Yellow-Green gas that is released from volcanoes and is deadly. However it is mostly used by people in compounds (this is when it is linked to other chemicals) such as bleach that your parents use to clean the floor or bathroom through to the salt that you put on your food. You can see from these examples that chlorine can be deadly, through somewhat poisonous right down to totally safe. - See http://www.aaawatertest ing.com/chlorine.htm The chlorine in your drinking water is used like the bleach you use on your floor in that it is designed to kill micro-organisms. In this case, the ones that are living naturally in water, but can cause sickness and disease in people - particularly when in large numbers. Therefore the chlorine added to the water is obviously poisonous - designed to kill. In Sydney Australia in 1998 our water was polluted with high concentrations of Giardia (parasite that is the most common cause of non- bacteria diarrhoea in North America) and Cryptosporidium (parasite that is passed through faeces) despite having chlorinated water. The result was that many people became violently sick and we were forced to go back to boiling their water. Sydney Water now strictly test and report on these micro-organisms - See the daily reporting at http://www.sydneywater.com.au. Learn more about "Bad Bugs" at http://vm.cfsan.fda.gov/~mo w/intro.html While chlorination can't guarantee to kill each and every nasty in the water it is currently one of the best ways of doing the job. Despite being poisonous, the good news about the chlorine added to your water is that it is strictly controlled in the western world. The other thing to take into account is that the compounds of chlorine added are very unstable. This means that they naturally break down and change form releasing the chlorine. Due to this it is likely that by the time you are drinking the glass of water it will contain little to no chlorine. Unfortunately it can still contain some other chemicals - Find out more at http://www.aaawatertest ing.com/chlorine.htm Despite all this I, like you, am still concerned about drinking chemicals that I can easily remove. I therefore drink filtered water but will make an effort to drink some tap water throughout the week - for the benefits of fluoride to my teeth and to ensure that my immune system is exposed to some of the micro-organisms that survive the chlorination process. I guess my answer is as unclear as others you have read. So here's the facts. 1) Water naturally contains many chemicals and potentially harmful micro- organisms. 2) Chemicals are added to drinking water in developed countries in the interest of our health - chlorine to kill micro-organisms, fluoride for your teeth (fluoride is another chemical that that many scientists are now saying is not safe). 3) The chemicals that are added are strictly measured. Chemicals already present (naturally) are strictly tested, as are bacteria and other micro- organisms. 4) The use of these chemicals has shown tremendous benefits in health in the countries that add them. 5) Studies show a slight increase in the incidents of colon, bladder, rectal (all organs used in the digestion and transport of water in your body) cancer in people who drink chlorinated water. So it's a matter of weighing up the risks with the benefits. In the meantime be sceptical about "the best invention in history" claims because the pesticide DDT was also labelled like this, as was CFCs in spray cans along with many other chemical inventions that were later found to be very damaging to people and/or the environment. For other non-chlorination ways of water purifying go to http://www.askjeeves.com and ask "how many ways are there to purify water". You'll see that chlorine may be the only way to mass-process water cheaply at the moment but there are other ways at home or camping. Time is the true test of what is a good invention - along with lots of research along the way. Maybe you can tell your grandkids what you think about Chlorine in 45 yrs when a better way is being used.
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