I learned quite a bit about plastics while doing this. I should say up front that I started out thinking, like the earlier comment "well, if it's good enough for potable water....."
I'm going to tell you why I changed my mind. I'd like to say that I don't think there's any way to talk about this stuff without sounding like a lunatic, especially to strangers. All I can say is go read the links and make up your own mind.
First was
this story story published last fall in the Milwaukee Journal Sentinel (not a subscriber, found it online). They summarized it like this:
A Journal Sentinel investigation found that the government has failed to regulate these chemicals, despite repeated promises to do so. The regulatory effort has been marked by wasted time, wasted money and influence from chemical manufacturers.
The newspaper reviewed more than 250 scientific studies written over the past 20 years; examined thousands of pages of regulatory documents and industry correspondence; and interviewed more than 100 scientists, physicians, and industry and government officials.
Among the findings:
• U.S. regulators promised a decade ago to screen more than 15,000 chemicals for their effects on the endocrine system. They've spent tens of millions of dollars on the testing program. As yet, not a single screen has been done.
• Dozens of chemicals the government wants to screen first have already been tested over and over, even while thousands of untested chemicals are waiting to be screened.
• By the time the government gets around to doing the testing, chances are the results will be outdated and inconclusive. The government's proposed tests lack new, more sensitive measures that would identify dangerous chemicals that older screens could miss.
• As the U.S. testing process remains grounded, hundreds of products have been banned in countries around the world. Children's products - including some baby toys and teething rings - outlawed as dangerous by the European Union, Japan and Canada, are available here without warning.
• Lacking any regulation in the U.S., it's impossible for consumers to know which products are made with the dangerous compounds. Many companies don't list chemicals known to disrupt the endocrine system on product labels.
The government's efforts have been "an abject failure, a disaster," said Philip Landrigan, a pediatrician and chairman of the department of community and preventive medicine at Mount Sinai School of Medicine in New York.
The reporter is starting to get some traction for her story in larger media outlets, CNN, PBS, etc. What I took away from it, at least as it relates to making earthboxes, is that the regulatory process is broken, and that any sign of doubt that actually makes it through a series of carefully designed media filters, should be heard as a scream. Experts agree that pvc is toxic to mfg, and to dispose of, that it's nasty when plasticizers are added to it (to make it more adaptable, e.g. i.v. drip bags, baby teething rings, but that it's "ok" in it's rigid form.
I'd also add this from the University of Pittsburgh's
Center for Environmental Oncology:
Are all plastics safe?
No.
You should avoid buying and using #3, #6, and #7.
#3 PVC (polyvinyl chloride, or vinyl):
PVC is hazardous in all of its phases: manufacturing, the products themselves in the home, and in the disposal of it.
One of the most toxic plastics, PVC is often used to make food packaging and in the production of plumbing and construction materials. PVC is commonly used in teethers and soft squeeze toys for young children, beach balls, bath toys (some rubber duckies), and dolls. Check the product or label to see what number plastic has been used.
To soften PVC into these flexible forms, various toxic chemicals are added as "plasticizers." Traces of these chemicals, known as adipates and phthalates, can leak out of PVC into your food. Some phthalates have been linked to cancer, kidney and liver damage, harm to developing reproductive organs, and premature breast development in baby girls. Inhaling these chemicals can also worsen asthma in children.
Because it contains a variety of additives and lacks a uniform composition, PVC is far less recyclable than other plastics.
Learn more about what makes up PVC: vinyl chloride.
Click here to learn about the alternatives to PVC that are available.
#6 PS (polystyrene):
#6 plastic may leach styrene into the food it touches. A recent study in Environmental Health Perspectives concluded that some styrene compounds leaching from food containers are estrogenic (meaning they can disrupt normal hormonal functioning).
Styrene is also considered a possible human carcinogen by the World Health Organization's International Agency for Research on Cancer.
#7 Other, most commonly PC (polycarbonate):
#7 polycarbonate may be able to release its primary building block, bisphenol A, another suspected hormone disruptor, into liquids and foods. Although several governments in Europe and North America currently hold polycarbonate tableware and food storage containers to be safe, this is a highly active area of research. Additionally, while category 7 most often refers to polycarbonate, it is actually a catchall "other" category, and it may not be possible to be sure just what it is. The Center for Environmental Oncology recommends avoiding these containers wherever possible.
So I've been avoiding #3, 6, and 7 whenever I can. I wouldn't call it a panic, more like pissed off. It's a huge hassle, but I don't want to be a guinea pig. I've only seen a couple of quotes in support of pvc (type #3). It's the medical establishment vs. the chemical industry. I'm following the MDs.
I first made the boxes with pvc, this year I took it out, replacing the screen supports with #1 PETE cups, and the fill tube with 1/2" poly (polyethylene) tubing. You can buy poly tubing stuff online from Lowes and they'll ship it free if you get more than $50 worth of stuff. Home Depot sells an adapter that screws on the end of a hose that fits inside the 1/2" fill tube or you can just put the fill tube
inside the hose (but it leaks a little.) 1/2" copper pipe also fits inside the 1/2" poly, and you can tighten it with a snap tie. So my water supply is a little copper/a lot of polyethylene.
If anyone wants to get together and talk about any/all/none of this I'd be happy to. Or if you want to come over and check out what we're doing, let me know.