8.09.2007

water is good, but "bisphenol-a" is bad?

A few months ago, my parents sent me a somewhat alarmist email about plastic. The concern? They ran across an article on the internet stating that hard plastic water bottles marked with recycle symbol #7 contained Bisphenol A and that this could cause all sorts of health problems.

So I did a little research of my own. A little browsing around the internet and journal searches turned up a few things...

First of all "#7" plastic doesn't mean a whole heck of a lot. This label means "other". 1-6 are all specific types of plastic, everything else is 7. Ok. So just because my two water bottles are labelled #7 doesn't mean I'm doing any harm.

However, Lexan (a GE brand), also polycarbonate, plastic, which I do know at least one of my water bottles is made from, does contain Bisphenol A. *Most* clear hard colourful plastics marked #7 are Lexan.

Searching around some journals, I found a few articles expressing some degree of concern about the effects of Bisphenol A in rats. Nothing terribly conclusive as far as I can tell (I am not a biologist, I know very little about physiology, or the kinds of methods used in those studies), but the authors consistantly called for further study, and advised caution.

While this is a whole other issue, it should be noted that whether you absorb enough Bisphenol A to do yourself damage, in the kinds of large doses which can be released into the environment during manufacturing, humans and other organisms in the area can be affected significantly. That in mind, it is up to you whether you choose to buy a new Lexan bottle or avoid doing so for environmental and social reasons. I bought mine years ago now and was unaware of any of this at the time. I might have considered choosing something else had I known, though I suspect most plastics manufacturing has similar consequences.

Back to the health issues... Being uncertain, I have more or less left my water bottles in the kitchen cupboard for the past few months. Usually, a lack of conclusive data leads me to ignore the cries of the internet and carry on whatever I was doing before. However, given the small amount of data indicating reason for concern, and consequences like birth defects, infertility, and breast cancer, I decided that drinking city water in a mug at work is a reasonable alternative to taking a water bottle of Brita filtered water from home. If I'm heading into the wilderness (a rare occasion) or a long day around the city, I'll take one of my bottles.

But today I read this: ScienceNOW: Common Plastic Ingredient May Be Cause for Concern

A federal advisory panel meeting here today concluded that a hormonelike chemical found widely in food containers, bisphenol A, could potentially be causing neurological effects in fetuses and children. Although the group's conclusion, based on a wealth of animal and human studies, falls short of supporting any kind of ban, the panel expressed "some concern" about the chemical and noted that people may want to reduce their exposure.

...
Still, critics accused the panel of ignoring many other relevant studies. They point out that 38 bisphenol A experts and other scientists who met at a workshop last November concluded that people are exposed to doses that cause many other effects in animals, such as enlarged prostate and larger body size. The consensus statement of the November group, which is in press at Reproductive Toxicology, describes "a great cause for concern with regard to the potential for similar adverse effects in humans."


I think I'll be leaving those bottles on the shelf awhile longer. Maybe it's time to replace them with an HDPE or aluminum bottle.



Here are some other references:

3 comments:

DancingFish said...

I drink a mug out of the water cooler too. I read about some studies about 3-4 years ago and switched a number of our Nalgenes to the white plastic/blue lid ones. What bugs me most is that people I told didn't care at all. Pretty colors don't make up for birth defects! I am glad it is getting more press now.

Anonymous said...

I still haven't seen compelling evidence convincing me that this type of processed chemical is worse than any other processed chemical. I am not saying I need empirical evidence...but I would like to see something other than 'cause for concern'. I drive with my girlfriends now and then and that is real cause for concern...I know that empirically.

physics*chick said...

I totally agree with you that there is need for more convincing evidence. What seems to be happening now is uninformed panic, and that is just never good. There needs to be serious study on this topic, and the reality is that it should have been done years ago to prevent the current alarmist response.

On the other hand, I've decided that in the light of a few studies that do show some "cause for concern", I'll use my lexan bottles only when I really need to take a bottle with me (ie. not in my office when a mug and the water fountain will do). I still use my nalgene if I go out and about. I'll probably buy a non-lexan bottle of some kind at some point, but given that I only use them occasionally I figure it is probably ok.