Chemistry 101 - BPA

I'm sure if you have been watching the news or walking by the baby stores you would have caught glimpes of this acronym on things like BPA-Free milk bottles etc. Not many are trained to recognize the chemical name and since these BPA-free products are usually 2-3 times more expensive than the regular ones you are using, my bet is you would have probably think they are just a marketing gimmick and pass on them.

Well, have a good read on what I'm about to tell you. Then go back to the shops and have a closer look. 

I'll try to avoid as much chemistry terms as possible. First of all BPA stands for Biphenol A. "Bi" means two, phenol refers to the benzene rings (the 2 hexagons) which are often refer as carcinogen (cancer causing). The problem with BPA is that beside containing the toxic benzene rings, it also disrupt the hormones in the body, possibly leading to development problem of the brain, behavior and prostate glands. 

Now, the polymer or plastic widely known as PVC, that is commonly used for pipes, flexible hoses and wire insulations uses BPA as a manufacturing ingredient to make the originally rigid and brittle plastic flexible and easier to manufacture. The problem is BPA that is added will migrate to the surface of the plastic, a process that is called leaching. That is why PVC has been banned decades ago for any uses that comes in contact with our food supply. But till now, PVC is still used for some toys.

Back to the usual milk bottles. The crystal clear glassy looking bottles are actually made of PC, polycarbonate, which looks beautiful and is also very resistance to breakage. Polycarbonate is made using BPA in the polymerization process.  It's recently found that the leaching of BPA increases tremedously under heat. The hot water that is used for making the milk formula is enough to cause a substantial release of BPA into the water. 

Many countries has expressed concern over this issue especially with the baby milk bottles. Canada has banned all PC bottles late last year. Few days ago, US FDA admited they have erred and underestimated the effects of BPA leaching from polycarbonate under certain usage condition (such as heat) and is currently moving to ban or replace all PC bottles from the shelves. Unfortunately our local media and government agencies have not picked up the tab and help raise awareness. Maybe they are still busy looking for melamine...

So have a closer look at the BPA-free products next time. I think taking health of the babies into consideration, the cost of these BPA-free products is worthed it. 

If you are wondering if your bottles are made of PC, a quick visual check should be able to give you a strong clue:

1. Is it a bottle for drinking liquid?

2. Is it almost colorless? (Not always though)

3. Is it hard (can't be squeezed by hand) and unbreakable

4. Is it almost 100% transparent (like looking through a piece of glass)

5. Does it bear the plastic identification of 7? See below

If your answer is "yes" for at least 1, 3 and 4 you can be quite sure it's PC. Meaning you should keep away from it. Point number 5 is a clear give-away.

Another plastic to keep away from is PVC, which bears the number 3. No container for food or water or even toys should be made of PVC.

Btw if you are wondering if your favorite plastic nalgene bottle is made of PC, it is. Color is added to these bottles for aesthetic reasons. Didn't you read the news last year?