Is your water bottle safe?

In a lot of backpacks, you'll find the iconic Nalgene bottle.

But are plastic water bottles, including Nalgenes, safe for hikers?

A recent article in USA Today describes concerns scientists have about the health affects of plastics, particularly on babies and fetuses in the womb. The two chemical culprits are phthalates and Bisphenol-A, which can act as "endocrine disruptors" that mimic human hormones. Even at very small levels, these chemicals can interfere with the development of reproductive systems.

So what does this mean for hikers? A few years ago the environmental website Grist blogged on the Nalgene bottle debate here and here. If you're concerned, at the very least, avoid #7 plastic. Many, but not all, Nalgene bottles are made of #7. You can find the numbers on the bottom of the container. A less toxic plastic is HDPE. Trouble is, most of those snazzy, colorful Nalgenes are made of #7. Those familiar with the "classic" Nalgene will recognize the somewhat boring HDPE variety.

I've only recently learned about these issues with plastics. I would think that pregnant women and young children should be particularly careful. For unrelated reasons, I've switched from bottles to Platypus hydration systems, which are made from #4 Polyethylene, which is a safer bet. If you want to avoid plastics altogether, there are variety of metal water bottles, including aluminum bottles from SIGG and stainless steel bottles from Kleen Kanteen.

Do you drink from Nalgenes? Are you concerned about their safety? Post a comment.