Do all polycarbonates contain BPA?

[Rebecca_Rxyz]

Hello,
I am an eighth-grade student currently conducting an experiment to determine if the amount of BPA commonly found in plastic has an effect on the heart rate of Daphnia magna. In my research, I have found that BPA is commonly found in polycarbonate plastics and epoxy resins. Since most people today are aware of the dangers of BPA, I am having a difficult time finding plastic that is advertised as containing BPA. Do all polycarbonate plastics contain BPA, or only a select type?
Thank you

[deleted-132180]

Hi there,

Unfortunately, I personally do not know the answer to this question. If you don't hear back from any other experts in this forum, I suggest that you also post this question in the physical sciences thread, since there may be chemists there who may know a little more about this topic.

Sorry that I couldn't be of much help--perhaps other experts will have a better idea. Good luck!

Connie

[deleted-204107]

Hi Rebecca_R,

BPA can actually be found in water bottles, lids for coffee cups as well as in pre-packaged salad containers. If any other Experts have any ideas that would great.

I hope that helped. If you have any more questions, feel free to ask.

Good Luck,
nikhita8

[SciB]

Hi Rebecca,

I read the wiki on BPA [http://en.wikipedia.org/wiki/Bisphenol_A] and learned that the plastic used to make CDs and DVDs contains BPA. Since these are not used for food they may contain higher levels of BPA than say a water bottle that people drink from.

The big question I can see in your project is how long you need to ‘soak’ the plastic item in water to leach out the BPA before you add it to your daphnia and measure their heart rate. The solubility of BPA in water is 120-300 mg per liter at 21C http://www.google.com/url?sa=t&rct=j&q= ... 1339,d.eXY

This is not very soluble and it may take several weeks for even a small amount of BPA to leach out of a CD. You could try heating the water to 60C and letting the plastic sit at that temp for an hour or so. I don’t know whether this would leach out more BPA, but most chemicals are more soluble in hot water.

I also read that BPA is used to make the thermosensitive paper that is used for cash register receipts. Apparently this paper contains fairly high amounts of BPA that can be transferred to skin so you could try soaking some in water and testing that on your daphnia.

In addition to CDs and receipt paper, you should also test the common things that people drink or eat from such as water bottles and polycarbonate food containers.

I hope this helps. I am really interested in what you discover in this project so please keep posting your findings as well as questions.

Good luck!

Sybee

[Rebecca_Rxyz]

Thank you all for your replies!
I was actually planning on filling the container with water, covering it, and heating the water to boiling (100C) inside of a steamer. It was also suggested to me that I could microwave the water for long periods of time (5-minute intervals or so) in an attempt to get more BPA to leach into the water. Would this make a difference?

[SciB]

Hi Rebecca,

I think boiling is probably the best idea although you could try microwaving also; but I would not do 5 minutes on high. I think that might destroy the plastic. You want to try things that people might actually do in the kitchen. Personally I don't microwave food in plastic containers because I am concerned that some harmful chemicals might leach out and also because it usually warps the plastic.

I would also include either a CD or thermo-printed paper receipt as a positive control. When scientists do experiments they usually have both a positive control that they know contains the test substance and a negative control that they know does not. Since you don't have pure BPA to use as a control, you should use something that you are sure will have BPA in it to verify that your assay is working.

Good luck!

Sybee