i am posting this on behalf of a friend named saqib shams .. he had made and account at pakwheels but was unable to start a thread due to some unknown reason..... Saqib is a Material science guy based in China... this concerns the use of pet plastic bottles in our biking tours.... i think we shud have a look in it and consider it also as it concerns our environment.
"Dear PW fellows and my dear countrymen, Salaam.
My name is Dr Syed Saqib Shams. I'm a materials scientist by profession. And I'm a hobbyist photographer, this leads me to travel locally and internationally.
I'm pretty new to PWs as a registered user, but I've been a silent reader for a while. I was inclined to make this post after noticing all the enthusiastic bike riders touring across the country on their bikes. I would like to highlight something fundamental here, I've noticed many of the tourers here use PET bottles (disposable water bottles by companies such as Nestl?, Aquafina, etc.). I would strongly implore you to refrain from using these bottles in your journeys. I'm sure you'd be wondering why. So please allow me to elaborate further.
Polyethylene Terephthalate (a.k.a. PET) is a thermoplastic polymer consisting of two major monomer blocks: Ethylene and Terephthalate. Ethylene in its polymeric form is pretty safe and harmless. But Terephthalate, not so much. Infact, repeated intake or large quantity singular intake is believed to be carcinogenic (causes cancer). There have been deaths reported to be linked to this already. So you'd be wondering why these big companies would sell water made from such a dangerous material? The reason is, PET as a polymer is not reactive to water so it's FDA compliant (safe to come in contact with food and water). It's low permeability makes it a suitable material for bottling carbonated drinks (pepsi, coke, etc.) because PET doesn't allow the gas to pass through it (increasing shelf life). But all this goodness changes when it is exposed to heat (or UV induced heat from sunlight, as is the case here). Infact the heat deflection temperature (HDT) of PET is quite low which means it would physically deform even if exposed to mildly higher temperatures such as 90 degree Celsius or higher. It happens because the bonds between ethylene and terephthalate monomers start to break. And then Terephthalate begins to leach out of the polymer matrix and starts contaminating the water contained inside our bottles. Repeated usage of such contaminants would eventually lead to cancer. This is why these bottles are meant to be disposable and used exclusively with liquids that are meant to be refrigerated throughout their shelf life.
So my dear brothers, i would suggest you use bottles which are made of polyolefins, such as HDPE, PP, etc. I am curious about why people wouldn't use those squeezable water bottles available for bicycles (made from HDPE) on their bikes, may be they don't fancy the squeezability?! I'd be inclined towards it myself, if I'm honest.
I hope people would pay more attention to this little detail in future. Please make no mistake about it, health is most important.
Thanks and happy riding."