Monday, July 6, 2009

Bisphenol-A (BPA) - What are we to make of it?

I have posted on bisphenol-A before, back at in the beginning of 2009 in response to a letter writer in the Straits Times. Then, I commented that it was probably just hysteria because we probably consume greater amounts of estrogenic substances than whatever can be found as a result of BPA.

[Bisphenol-A (BPA) is a chemical found in hard plastic bottles.]

But recent presentations at the recent Endocrine Society ENDO09 meeting are threatening to rewrite this thinking.

Dr VandeVoort and his co-workers from the University of California, Davies reported that if female rhesus monkeys are treated with a single oral dose of BPA that is 8 times higher than the estimated 'safe' human dose, the serum concentrations of BPA are less than what has been ordinarily found in humans. In addition, when Frederick vom Saal of the University of Missouri-Columbia and colleagues administered 4,000 times estimated typical daily human consumption to 11 rhesus monkeys, BPA blood residues in the spiked monkeys ended up only one-eighth as high as seen in a German study of pregnant women. Both these studies implied that human consumtion of BPA is higher than what has previously been estimated. Dr vom Saal estimates that typical human daily consumption may be as high as 1000 micrograms per kg body weight per day.

In yet another study (in press) Dr Michels reports that students drinking from plastic bottles over a one week period showed 69% higher BPA levels in the urine compared to if they drank from steel containers. (FDA safe upper limit is only 50 micrograms per kg body weight per day

So what do we make of it?

I must admit that the data is making me change my mind about the safety of BPA. What is particuarly worrying is that the plastic industry isn't taking this lying down and appears to be poised with some rather aggressive and scary counter-intelligence efforts.

The AVA is supposed to regulate the chemicals in our environment. I hope it has been following some of these developments. It has to constantly review its position about BPA.

A particular difficulty for us I think is the fact that one of our major long term industrial partners here in Singapore is Mitsui Chemicals. Through its local subsidiary Mitsui Bisphenol Singapore Pte Ltd (MBS), it is a major producer of BPA.

I hope the AVA is adequately china-walled against industrial/economic considerations to be able to do the right thing by us.

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