When the plastic of water bottles is exposed to light some atoms come off from it and blend with the water, so my question is which are the chemicals and its effects

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    $\begingroup$ Do you have a reference for this? $\endgroup$ – jonsca Jul 13 '14 at 0:13
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    $\begingroup$ Yes, I would second @jonsca, it would be helpful if you could provide a reference to a specific example. Photodegradation of polymers is a real phenomenon, but this is distinct from dissolution of the polymer. As far as I know, a bigger problem is the leaching and/or off-gassing of more volatile polymer additives (e.g., plasticizers). Thermal and acid/base-induced degradation are at least equally significant (depending on the polymer in question) as well. $\endgroup$ – Greg E. Jul 13 '14 at 1:05
  • $\begingroup$ Incidentally, and separate from your question, there are plenty of companies that manufacture bottles and other products free of plasticizers. You can also minimize any possible exposure by taking simple and obvious precautions: avoid heating the plastics, keep products refrigerated when possible, avoid exposure to light (especially UV), do not use harsh cleaners on the plastics (i.e., anything beyond simple detergents and water), do not store highly acidic or highly basic liquids for extended periods of time. $\endgroup$ – Greg E. Jul 13 '14 at 1:21

It all depends on the polymer used in making the plastic bottle. I have heard that some of these chemicals you refer to are carcinogens. I won't pretend to know the formula nor the name of these carcinogens. However, the polymer must ve, to some extent, photodegradable given that the breakdown that you speak of occurs after being subjected to light. This would indicate that the polymer chain has a carbon oxygen double bond as part of the main "backbone" of the polymer and will have been formed by condensation polymerization. This may help to indicate the type or chemical that you're asking about.

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  • $\begingroup$ I agree that it's crucial that the OP be specific about the polymer in question, but it need not contain carbonyl groups to be vulnerable to photodegradation. Polypropylene, polybutadiene, polystyrene, and low-density polyethylene are some examples -- there need not even be any $\pi$-bonds, chromophores, or heteroatoms at all. $\endgroup$ – Greg E. Jul 13 '14 at 8:44

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