Is it true that you shouldn't leave a water bottle out in your car when its sunny outside?

Question

I heard that if you leave a water bottle in your car, the sun's UV rays can somehow react with the plastic bottle, and this reaction emits certain chemicals into the water in this bottle. I tried to find some information on this online, but had no luck. Anyone out there know anything about this?

Answer 1

No, it is not true. This is an urban legend based on a non-published masters thesis.

Answer 2

No, this is an urban legend.

First off, if you leave the bottle inside a car, the glass of the car will block the UV radiation. So unless you're leaving the bottle in the back of a convertible, there's no worries about UV and the plastics.

Second, all plastics used for foodstuffs and other edible/drinkable materials have been extensively tested under the most ridiculous conditions to guard against just that possible scenario. Heat, cold, sunlight, darkness, electromagnetic radiation -- you name it, they've tested for it.

What you will end up with is hot water in a bottle that may deform permanently. But the amount of chemicals that will leach into the water is negligible.

So, as the Aussies would say, "No worries, mate!"

Answer 3

I see many people talking about "temperature" when answering this question. The photons emitted in the ultraviolet area of the electromagnetic spectrum have nothing to do with heat energy- that would be Infrared energy. Therefore, all of the breakdown and melting temperatures have no value in answering this question. UV has enough energy to produce many different photochemical reactions, and the breakdown of plastics can be easily observed. Have you ever left something made of plastic outside, to come back and find that the plastic has become dry and brittle? This is an effect of the UV emitted from the sun. The brittle areas are where the plastic has broken down because UV energized photons have penetrated and broken the polymer bonds. These breakdown products don't just disappear- they have to go somewhere...like into the water that surrounds the plastic.

As mentioned above, UV cannot penetrate glass, so leaving it in your car is not an issue- unless your window is rolled down. Direct exposure from the sun is when this process occurs.

The argument lies in if these breakdown products are unsafe to ingest...and that's a whole different question.

Answer 4

It is totally untrue! If you look at the bottom of most water bottles you will see that they are made out of PET (Polyethylene terephthalate). The "glass transition temperature" is the temperature defined by which the plastic becomes slightly more mobile, but will not melt. The glass transition temperature of PET is 75 C, or 167 F. You would have to be parked in the middle of the desert in dead summer in direct sunlight for the car to get this hot. The typical "hot" parked car only reaches about 130 F, though this can still be lethal.

The melting point of PET plastic is about 260C, about 500F...the maximum point of most ovens. No car will ever get this hot.

The other fallacy to this theory is that most UV radiation is stopped by glass...which is why you don't get sunburned when you are behind a window. Most UV rays will not even get through the car window, and the few remaining will be stopped even further by the bottle itself...the amount that could actually get through to the water would be quite negligible.

So don't worry about leaving your water bottle in the car. It may not be tasty to drink hot water, but there will be no funny chemicals in it by doing so.

Answer 5

There are small organic molecules in plastics that will leach into the water. This will happen faster if the plastic and the water heat up, but it probably does not affect your exposure much because the water has probably been in the bottle for several weeks already. Chemicals known to be dangerous by ingestion are not allowed to be used in plastics for food packaging. However, there are scares from time to time when the safety of various chemicals is called into question. For example, phthalates have been suspected to mimic estrogen, but this concern mostly blew over once studies were done ( for example, see http://www.mindfully.org/Plastic/Estrogenic-Phthalate-Esters.htm) .

When deliberately added to plastics, these small molecules are called plasticizers. Their purpose is to soften the plastic. Over time, they evaporate away, and the plastics become hard and brittle. The loss of plasticizers will definitely happen more quickly if they are left in a hot car. More info about plasticizers here: http://en.wikipedia.org/wiki/Plasticizers and http://en.wikipedia.org/wiki/Phthalates

Answer 6

No in no way. particularly in case you keep chilly water in a Sterile puppy bottle (not an elementary Plastic Bottle) and go away it in sunlight many of the bacterias present day interior the water gets killed and boiled water is powerful for the digestive device. particularly no person makes use of the bottle for long term and all are throwaways in basic terms. in case you have such apprehension you are able to avert taking water from plastic water bottles.

Answer 7

yes its true because the plastic from the bottle starts to melt at certain temperatures and thus causing a chemical imbalance in the water maybe even leading to poisoning due to the plastic if someone drinks the water.

Answer 8

this is infact true (what the first girl said). this is not an urban legend. My General chemistry teacher at my college told me about it.

Answer 9

Really ? When did that came up ?

Answer 10

I've heard that too.