I'm from Mexico City and lived in the U.S. for a total of more than 24 years. Now I'm back in Mexico. I realized I was seeing my country through the eyes of a native stranger. This is an attempt to process the differences, to explain Mexico to the U.S. and the U.S. to Mexico. With digressions along the way.

lunes, julio 25, 2005

Unsafe Plastic?

I have these old #1 PETE plastic Powerade bottles that I refill from my Britta to drink water near my computer and when I leave the house. They no longer make them in the U.S. (you can get a similar Gatorade bottle in Mexico), which is why I have reused the same ones for many years. The reason I love them is that even when uncapped, they won't spill if they fall over or even if you hold them upside down. They have this little one-way valve (a lot like an arterial valve) that only lets water out when you suck on it. (I don't like push/pull drinking caps because they aren't spill proof and they end up hurting my teeth.)

So then a friend of mine pointed out that it's bad to reuse polyethylene terephthalate (AKA PET, PETE) plastic bottles because the plastic breaks down with detergents and heat and it can leach chemicals into your water. AAAAUUUGH!! So he said he's going to buy me a Nalgene bottle, which is really cool of him. OK, I think, maybe I can part with my lovely valve for safety's sake. BUT NOW I READ THAT NALGENE BOTTLES CAN LEACH HARMFUL CHEMICALS TOO! So I set down to do some research and get to the bottom of this. Is there a safe plastic to use? Or will I have to switch to heavier glass or stainless steel bottles? Does it even matter, considering we get toxins from all sorts of stuff in our environment constantly? I mean, the plastic that most Nalgene bottles are made of, Lexan (AKA polycarbonate, or #7 PC), is also found in dental fillings, of which I have several. And, well, uh...my Britta filter pitcher is made of plastic (who knows what kind) and I've had it for years and years.

On one hand, I think that there's a lot of hype surrounding safety issues in the US that keeps people busy from concentrating on real issues. On the other hand, I think we do live pretty toxic lives because of all the chemicals we are exposed to in "modern living" and I want to minimize exposure to ensure my health. Life expectancy is much longer than it used to be (according to the US National Center for Health Statistics, life expectancy at birth went up from 47.3 in 1900 to 77.3 in 2002), but supposedly so are cancer rates (hard to find a reliable statistic for that, because there are so many of them and not all seem to be scientifically rigorous enough--for example, taking into account that people live longer and thus have more time to develop diseases).

For what it's worth, here's my evaluation of all the information I could find on the internet:

First of all, there are various kinds of plastic out of which food and beverage containers can be made, all approved by the FDA (which is no guarantee of safety in my opinion--they are too influenced by corporate interests):

  • POLYETHYLENE TEREPHTHALATE (polyester, PET, PETE, recycling code: #1 PETE) These are the most common for soft drinks and bottled water. If it's a hardish, completely clear plastic bottle, it's most likely PETE. You can tell by looking at the recycling code, which is #1 PETE.
  • POLYVINYL CHLORIDE (PVC, vinyl, recycling code: #3 V)
  • LOW DENSITY POLYETHYLENE (LDPE, recycling code: #4 LDPE)
  • POLYPROPYLENE (PP, recycling code: #5 PP) A lot of condiment and yoghurt containers, as well as those semi-disposable tupperware containers, are made of this one.
  • POLYSTYRENE (styrofoam, PS, recycling code: #6 PS) Styrofoam cups, take out containers, etc. It doesn't always come as a foam. A lot of disposable plastic cups are made of PS, as well as cling-wrap.
  • POLYCARBONATE (Lexan, PC, recycling code: #7 PC) Nalgene bottles. Preferred because they are strong and don't retain tastes and odors. (Don't think that all #7s are polycarbonate--#7 is just for "other" plastics).

[For more information on this classification, check out this table.]

So, checking this subject out on the internet you get wildly differing opinions, which often appear to be based on improper evaluation of sources. I think it's safe to say we really don't know how safe these plastics are to use--they will need to do a helluva lot more testing to determine that. Avoiding all plastic is too difficult. I'm not going to stop buying Stonyfield yoghurt because it's in a plastic tub. But maybe I will stop re-using my plastic water bottles over and over or use one of the "better" plastics if there's a risk of bad chemicals getting into my water. So, IS THERE A RISK?

Here's a summary of information on each plastic:

Why might there be a cause for concern?
Apparently a University of Idaho student claimed in a master's thesis that there was some chemical leakage danger from PETE, but then this got picked up by an email chain letter and is regarded mostly as a hoax (read about it on Snopes.) Critics say that the study the student did was not peer-reviewed and that PETE leaching does not occur, but they support this with what the FDA says, which is just based on no one having done a study that they reviewed that proves that it does occur (very very lousy logic). The Snopes article even quotes the International Bottle Water Association, which is hardly impartial. On the other hand, a bunch of other articles refer to PETE leaching as a proven fact based on this DEHA leaching claim that got picked up by the media, which has not been proven reliable at all. Other articles claim that this type of plastic leaks acetaldehyde and/or DEHP. I'm trying to look into the studies that are the unstated support for these claims.
Several articles say the real danger is bacteria that can build in the bottle if not properly washed. At least a couple of articles reviewing the safety of plastics in the food industry say to stay away from this type of plastic for that reason. But unless there's some specific reason this plastic makes bacteria thrive, I don't see how reusing these bottles is any more dangerous than using any of the other kinds. Plus I think a little harmful bacteria keeps your immune system sharp...heh.

Often cited as a "safe alternative," though I guess it does retain odors. Some sites list several chemicals it leaches. The thing is, all plastics can leach chemicals under certain conditions that cause the plastic to break down: heat, acid, other chemicals, physical stress, etc. The only website I found that mentions HDPE leaching does not cite any studies so it's hard to evaluate what test conditions they used and if they resemble what your daily use would be. I haven't looked into the toxicity of the chemicals listed by that site.

POLYVINYL CHLORIDE (PVC, vinyl, recycling code: #3 V)
Why might there be a cause for concern?
The phthalates (which are considered to be harmful chemicals) that are used to soften PVC and make it pliable could leach from the bottle. In addition, when they incinerate it, it releases dioxins into the environment.
Should I really worry about this?
I'd avoid this plastic as much as possible. Which may be impossible considering it's so prevalent. Some people claimed that even PVC tubing used for plumbing can leach harmful chemicals. Another good reason to use a filter. There are plastic cling wraps that don't use this type of plastic like Glad and Saran wrap. Most delis use the bad PVC kind.

Same as HDPE, often menitoned as a "safe alternative," with same odor-retention caveat. May leach same chemicals as HDPE.

POLYPROPYLENE (PP, recycling code: #5 PP)
Why might there be a cause for concern?
A study done on polycarbonates (see below) showed that a PP container used as a control also leaked an endocrine-disrupting chemical--nonylphenol. However, many sites list PP as a safe alternative, so the question is how and how much does PP leach toxic and endocrine-disrupting chemicals.

POLYSTYRENE (styrofoam, PS, recycling code: #6 PS)
Why might there be a cause for concern?
Leaches styrene, which is a probable carcinogen, and other chemicals that are endocrine disruptors. There doesn't seem to be much controversy on PS. Everyone seems to agree it sucks.
Should I really worry about this?
I'd stay away from it as much as possible.

POLYCARBONATE (Lexan, PC, recycling code: #7 PC)
Why might there be a cause for concern?
Two studies have shown that the chemical bisphenol-A (BPA) can leach from PC plastic. BPA has been linked to endocrine activity disruption and reproductive impairment in mice and rats in many studies. You can read a typical explanation of the these two PC studies in this Balanced Living Magazine article. You can read about late 90s studies that say PC is safe in this report. I think this San Francisco Chronicle article has a fair view on the matter. There are two separate questions:
1. Does enough BPA leach from the plastic in ordinary daily use to be significant?
2. Does BPA in small quantities harm humans?
Who did the studies and what do the studies actually show?
The first study was done on mice by Dr. Patricia Hunt, a geneticist at Case Western Reserve University in Cleveland. In an unrelated study in 1998, her team noticed an eight-fold increase in chromosomal abnormalities in the mice, and found that the culprit was the presence of BPA released by washing PC containers with a harsh detergent. This led them to reproduce the effect in a study specifically for that purpose.
A 2003 study (Howdeshell, KA, PH Peterman, BM Judy, JA Taylor, CE Orazio, RL Ruhlen, FS vom Saal, and WV Welshons 2003. Bisphenol A is released from used polycarbonate animal cages into water at room temperature. Environmental Health Perspectives doi:10.1289/ehp.5993.) showed that BPA was leached into water even from new PC, but old PC leached at 10 times the rate. This test was mainly done out of a concern that using PC cages for animals involved in experiments dealing with the effects of various agents on reproduction might affect the results. It was latched onto by other people as evidence that PC is unsafe to use even at room temperature and when new.
Should I really worry about this?
To be on the safe side, I'm going to assume that BPA is bad for you. The question is then if ordinary use of a PC water bottle will increase your BPA intake. Since it seems pretty clear that the older and more worn the plastic is, the greater the BPA leach is, I think a moderate answer is to wash your Nalgene or other PC bottle by hand using a mild soap, don't stress it with extreme temperatures like boiling water or put it in the microwave, and discard it when it's old or damaged. Actually, you could say that's good advice for all plastics.

So, what's the best choice for plastic? Who knows, but HDPE #2 and LDPE #4 have the fewest claims about leaching, followed by PETE #1 and PP #5.

The Verdict? I think I'm gonna go with a stainless steel bottle until my paranoia turns into apathy and then I'll probably go back to using the PETE #1 bottles if I can find the cool valve ones again. Maybe I'll just be careful about reusing them for too long and won't wash them in the dishwasher.

If you're looking for an alternative to plastic, here are two choices:

1. Klean Kanteen is a stainless steel water bottle. Simple.
2. Sigg makes very chic aluminum water bottles that come in a wide variety of styles and have lots of accessories. You don't have to worry about the aluminum because they have an inside coating: a baked-on "taste-inert, food-compatible stove enamel"--but do you have to worry about the coating? Supposedly not since they changed it to a water-based resin. You can read details here.

jueves, julio 07, 2005

Violence Begets Violence

My thoughts are with the people injured and killed in London today, as they are every day with the people injured and killed in Iraq and everywhere violence creates unnecessary suffering, though they don't get as much attention from our media, though we see those figures and can't help but half-digest them as mere numbers or statistics, far from our lives of routine.

Bush says the "contrast couldn't be clearer between the intentions and the hearts of those of us who care deeply about human rights and human liberty and those who kill, those who have such evil in their heart that they will take the lives of innocent folks." If you take the "of us" from his words to extinguish its sickening hypocrisy, I couldn't agree more.