This started as a reply to Bryan's comment on the Freaky Frogs post, but it quickly turned into its own blog entry...
Here's Bryan's comment:
I thought the whole BPA freakout was an interesting look at how we think about environmental and personal contaminants like this. People seemed to get all up in arms about BPA in water bottles and bought tons of new plastic or aluminium vessels to replace them. But that switch over raised some questions for me.
Where did all those old bottles go? In the trash?
How much energy does it take to make those aluminium bottles? Is it lots more than the plastic ones?
How many bottles can you own before it'd just be better to use disposable paper?
Courtesy US Government
And my response...
It took some searching, but I did find one article discussing a life cycle analysis from Australia which showed that, in a comparison between aluminum, stainless steel, and plastic, plastic has the smallest carbon emissions footprint, uses the least water, and produces the least manufacturing waste. However, it was unclear whether this comparison included recycled metals in its evaluation. Steel and aluminum are 100% recyclable (vs. plastic, which loses quality every time it's recycled), so over time and on a large scale, their use would lead to less material waste.
Courtesy Matthew Baugh
It's also interesting to note that recycling metals uses significantly less energy vs. what it would take to smelt "new" metal. To paraphrase this reference, recycling steel and aluminum saves 74% and 95%, respectively, of the energy used to make these metals from scratch. As it turns out, we recycle about half the steel we use in a year in the US, and so almost all the steel we use contains recycled content. In contrast, we recycle just 7 percent of the plastic we use.
And then there's glass--we have lots of options, really.
Courtesy Ivy Main
I can't speak to how much material was wasted when people discarded all those bottles (I think I recycled mine?). Personally, I do think that making reusable bottles in general uses less energy than is needed to make all those disposable plastics and recycle them--at least in terms of lifetime footprints. Of course, when it comes to a strict comparison between reusable bottles, switching to a new bottle will always consume more energy than just sticking with your old one.
Unfortunately, it turns out that most plastics, even the ones labeled BPA-free, leach estrogen-mimicking chemicals. So if you're looking for a long term solution, it may be best to just avoid plastics altogether. This does seem to be one of those cases where we have to consider our own health vs. the environment and pick our battles wisely. If people want to switch once to avoid health problems, at least they're still sticking with reusable bottles. Readers, do you agree?
Of course, it would be great if choosing a water bottle were the only drinking water issue we faced. The other day I read about a study by Environmental Working Group, which found that the carcinogen chromium-6 contaminates tap water throughout the US. Are we exposing ourselves to this toxic metal by drinking tap water instead of pre-bottled water? Or is chromium in the bottled water, too? What about other unregulated pollutants in our water?
I guess my point of going into all this is that it's complicated to make these decisions, and we'll probably never be able to avoid every single toxic substance. But does that mean we shouldn't try to make drinking water safer?
For now, I'm gonna stick with the steel and aluminum bottles that I already have and try to get the most out of them. Luckily, I live in the Twin Cities, which don't rate high on EWG's chromium map. Every day, I learn more about my health and the health of our environment, and hopefully by searching, I'll find a direction that hits on a fair compromise.
We've written about freaky frogs on the Buzz Blog before, but some recent news may shed new light on our abnormal amphibians. Until recently, researchers thought that atrazine, an agricultural pesticide, was the sole cause of sexual deformities in frogs. Unfortunately, it's not so simple.
Courtesy Mike Ostrowski
An ecologist at Yale University, David Skelly, sought to test assumptions about atrazine by studying the frequencies of frog deformity in different land types--agricultural, suburban, urban, and forested. Skelly expected to find the highest rates of deformities in agricultural areas, which would be consistent with atrazine being the main cause. Curiously, he found the highest rates of deformity in urban and suburban areas--places we wouldn't expect to find much atrazine. So what's going on?
It turns out that what makes atrazine so dangerous is that it mimics estrogen and binds to estrogen receptors in frog cells. Because estrogen impacts sexual development and function, so too does atrazine. But atrazine isn't the only estrogen-mimicking compound out there--there's a whole class of chemicals that mimic estrogens, including those found in birth control pills and plastics (BPA). And these chemicals are found in droves in cities and surburban areas--they're flushed into the sewage, but aren't filtered out during water treatment.
So why do we care? Besides the fact that frogs are just awesome little creatures and important parts of their food webs, they have something in common with humans--estrogen receptors. The same chemicals that impact frogs can impact us. So how do we humans keep our sexual development and functioning intact?
Skelly had a great idea to filter this stuff out of the water at the treatment plant, so that it won't get into our bodies from drinking water. He also suggested that regulatory changes would help so that when new chemicals are developed, they're scrutinized for unintended side effects. And of course, we can make choices that reduce our exposure, such as by buying BPA-free plastics, or using stainless steel and glass containers. And of course, increased awareness is always a good idea.
Do you take extra steps to avoid things like BPA? What are they?
Courtesy sirgabeThere’s something I want to get out of the way straight off the bat: the original title for this post was “Monday Nutrition Extravaganza: Chemicals in your food, playing with your manhood!” And while that has a certain whimsical charm, a re-read revealed hidden, disturbing meaning in those words. And I didn’t want to subject you Buzzketeers to that. I just thought you should know.
So, moving on, what’s this stuff playing with our manhood, now?
Chemicalz in our foodz! And stuff.
Earlier today, I came across this study about how there seems to be a correlation between high levels of chemicals call phthalates in pregnant mothers’ urine, and a lowered incidence of “masculine play” in their male children. (“Girls’ play behavior” didn’t seem to be affected.)
Phthalates are a group of chemicals added to plastics to make them softer and more pliable. We all like soft plastic—no one is arguing that!—but phthalates are all over the place, and increased exposure to them (all sorts of products and packaging use phthalates) is raising concerns about how those chemicals affect us, particularly during childhood development. See, phthalates are antiandrogens, meaning that they mess with the way your body works with hormones like testosterone. Testosterone plays an important role in how we physically develop, and perhaps in how we act. The boys whose mothers had higher levels of a couple kinds of phthalates demonstrated less “male-typical” behavior. The study looked a preferred toy types (trucks versus dolls), activities (“rough-and-tumble play”), and “child characteristics.”
Now, these are slightly sticky things to go judging kids on. Some folks might argue that these characteristics aren’t linked to biology so much as social conditioning. And it feels a little weird quantifying characteristics in children (and, let’s be honest here, characteristics which may not have a solidly identified “norm,” but nonetheless have all sorts of social and sexual baggage that we are uncomfortable with and often deal with in the worst ways). However, there does seem to be some statistical association here, whatever the causal relationship is. One hypothesis is that phthalates alter fetal production of testosterone at an important period of development, affecting “brain sexual differentiation.” It’s not so hard to imagine—a year ago I did a post on how certain common chemicals in pregnant mothers seemed to be causing penis deformities in their male children. The culprit there? Phthalates. The women in that story, however, had had exceptionally high exposure to phthalates (their jobs had them in constant contact with phthalate-containing hairspray), so it’s probably not something to lose sleep over, but it’s worth knowing.
And while phthalates aren’t supposed to be in food packaging, the next article I came across (this is an extravaganza, after all) deals with another plastic additive, BPA, that is found in food packaging, and which may also cause some hormone-related havoc.
BPA has come up on Science Buzz before. It’s in all sorts of packaging and bottles (it’s the reason your over protective mother doesn’t want you to use nalgene bottles) and it may affect tissue development, potentially increasing cancer risks.
We don’t care about that, though, right? Sure, cancer is out there, but in the future, not right now, you know? I know. But BPA’s latest appearance in the news may bring some immediacy to the concern over its use. Concern for some people. For men, I mean.
Chemical BPA in workers related to sex problems, says the Washington Post. “Sex problems”? We don’t want those! Chinese men working in a factory that uses BPA were found to have high rates of sexual problems. (I won’t be defining what “sexual problems” are because whatever you just imagined was probably correct.) Now, these guys have BPA levels about 50 times higher than the average American. But, still, something like 90% of Americans have detectable levels of BPA in their urine. Again, probably nothing to lose a lot of sleep over, but something worth knowing about. This professor is of the opinion that BPAs should be banned, even though most of us will probably never be exposed to dangerous levels of it, because a) it’s not a natural part of our diet; b) it’s not actually necessary in plastics processing; c) it accumulates in the body, and we still don’t know what level at which it begins to become harmful (ask those Chinese guys); and d) it’d be relatively easy to get it out of the food and water supply, unlike some other potentially harmful chemicals.
Accepting that scientific studies are necessarily very focused to eliminate variables, both of these stories still left me wondering what affect phthalates and BPAs have on women and girls. On one hand, one tries to avoid the mindset that average human physiology=male physiology, but on the other hand it’s usually just males that have penises, making their medical problems a little more hilarious.
There are so many… things out there, and they’re all doing… stuff! Interesting to know.