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Author Topic: Does chlorine in tap water react with constituents of plastic bottles?  (Read 11792 times)

Offline decepticon

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i have noticed that when i have finished with a plastic bottle and refill it, the tap water i refill it with smells horrible the next day or two. if i leave the original bottled water in it for a few days it does not smell at all.
i was wondering if the plastic bottles are engineered somehow to react with the chlorine in tap water to produce a funny taste/smell to prevent people from refilling them.
i have waterbottles for use on my bike and these dont suffer from the same problem.
opinions please
cheers
neil

[MOD EDIT - PLEASE PHRASE YOUR THREAD TITLES AS QUESTIONS IN FUTURE, IN LINE WITH OUR FORUM POLICY. THANKS. CHRIS]
« Last Edit: 27/09/2009 19:39:03 by chris »


 

Offline JimBob

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I do not know about the UK, but the word on the streets here is that the water bottles that are soft plastic (most of them) as opposed to ridged plastic actually start to decompose when exposed to oxygen. To avoid all of this I have bought an aluminum bottle with a melamine stopper in the top which has an opening to allow the water out and air in.

Need to get this answered by a UK person for specifics in the UK.
 

Offline Don_1

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There have been a number of stories around about this. It was suggested that the single use bottles made from polyethylene terephthalate known as PET's (the soft plastics JimBob referred to) used for water and soft drinks can release dioxins when reused. In fact, there are no dioxins in this material.

What may be going on, is that you are not cleaning the bottle sufficiently to kill bacteria which get into it from your own mouth when you drink from it. These bacteria, while not harmful in your mouth (indeed most are beneficial) may become the food for algae in the bottle.

Decomposition when exposed to oxygen, I'm not so sure about. If this were the case, then the bottle filled with it's original contents would be at risk. My only other suggestion would be that there may be a reaction between the plastic and chlorides or fluorides in the tap water.

Of course this could be yet another conspiracy by the bottle manufacturers. Put these rumours around to stop people reusing bottles and buy purpose made bottles instead. More revenue for the bottle manufacturers.

Personally, my favourite contender is the bacteria. Maybe these bacteria from your mouth could even be attacking the plastic. I would suggest giving the bottle a good cleaning with detergent rather than a simple rinse and only use it a few times, then discard and replace. Or (& no I'm not a bottle manufacturer) buy a purpose made bottle. But you must still clean in out properly, or that will get bacteria in it.
 

Offline techmind

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I re-use plastic (PET) soft-drinks bottles for tap-water and usually manage to make them last several months before they start to smell bad. I probably change the water at least twice a week, normally rinse them out with a good shake too (occasionally use detergent), and keep them in the dark. In the UK the ambient temperature is rarely much above 23 Celcius (and often much less). I probably also keep them mostly 2/3rds full to 100% full. It wouldn't make sense to carry round an empty bottle.

There does come a point though where no amount of rinsing and detergent-washing seems to keep them smell-free for more than a couple of days. I suspect that at that point something's grown/attached to the inside surface which no-longer washes out properly. (Then I can justify buying a soft drink!) Bear in mind the lids sometimes contain a plastic 'washer' thing which you may not be cleaning behind.


(I use soft-drinks rather than single-use "water" bottles as the soft-drinks ones are stronger and I'm much more confident they won't rupture in my bag.)
« Last Edit: 21/09/2009 22:28:09 by techmind »
 

Offline Max Clark

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  Plastic bottles made from PET plastic are used for water bottles, soft drinks, beer, teas, power drinks, etc.  PET plastic is durable and does not leach harmful chemicals.  PET plastic is durable, so durable that we're having problems getting rid of the stuff.  If it makes it into a land fill it will languish for hundreds of years. 
Several companies have introduced plastic bottles that are reported to be "greener."  There are basically three types of plastic bottles being produced, bioplastics (PLA) made from plant starch, oxodegradable (PET with an additive that causes the plastic to degrade), and the ENSO biodegradable plastic bottle (PET with an additive that causes the bottle to biodegrade in a microbial environment).
PLA plastic is a horrible bottle, it warps in the sun, the taste of the water is affected by exposure to the sun, the bottle doesn't biodegrade (it can be composted but only in  a commercial composting facility), is made from genetically modified corn, increases the use of pesticides.....on and on, you get the idea. 
Oxodegradable plastic bottles are designed to degrade due to exposure to oxygen.  Oxodegradable have limited shelf life.  Oxodegradable plastic bottles don't biodegrade, they degrade into smaller and smaller pieces until it no longer can be seen.  The plastic remains in the environment, just invisible.

Mod edit - spammy and self serving bits removed
« Last Edit: 22/09/2009 17:14:50 by BenV »
 

Offline decepticon

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just as usual there always seems to be a few people who know something about a question posted and aid the learning of others, thanks to everyone for the replies.
maybe the bottle manufacturers are 'engineering' the bottles to react with chlorine/oxygen to prevent refilling, but no doubt their reasoning would be to 'improve recycling/biodegradability'.
cheers
neil
 

Offline LeeE

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This has been an interesting thread to follow because I've been using three x two litre plastic 'take-away' beer containers to hold water that I keep in the fridge: they fill up the empty space in the fridge, making it more efficient as less air is circulated each time the door is opened, and when it's hot I've got some chilled water.

I've been using the same three containers for more than five years and haven't washed them once while I've been using them and don't rinse them between re-fills, which is about once every ten days or so (although I did initially wash them with detergent before I started using them).

There appears to be no build up of algae in them and no bad smell either.  They're also about fifteen years old (but have always been kept in the dark, so no UV damage), so I think it's unlikely that they're made out of anti-bacterial plastic either.  I'm actually a bit surprised myself, at the lack of algae.

The only significant things I can think of are that they're constantly refrigerated and that they are not very air-tight (they have a low-pressure relief valve built into the lids to allow the gas from the beer to escape without building up too much pressure).  Perhaps more importantly, I never drink directly from them and when I refill them I hold the neck right up to the tap so that there's only a very small gap, partly so that there's a positive airflow out of the bottles and also so that I can 'play' with turning the tap off/down just before the bottles are filled and the water sprays out everywhere.  I also fill the bottles to the brim, so there's very little air in them until I start using them.

I really would have thought that I would have had to clean them by now and I'm still surprised at how 'clean' they seem to be.
 

Offline Don_1

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I think the fact that you don't drink directly from the bottles and the conditions they are kept in explain the lack of algal growth in them. Probably the chloride in the water ensures that, given the conditions, there is no chance of anything surviving.

BTW, 10 points for environmental frugality.
 

Offline Karen W.

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This has been a great source of information regarding the reuse of these plastic bottles and the pros and cons of which kind do what  etc... Thank you all for some great information..
 

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