Nemo,

Okay, I'll try to answer your questions.

1. Recyclability (is that a word?): The HDPE are much easier to recycle. There's already companies that turn used HDPE into new, useful item. Patagonia is one manufacturer of outdoor gear which specializes in using recycles HDPE. In my experience I've never heard of anyone recycling Lexan (polycarbonate) material. I'm not sure if they even can be recycled.

2. I'm not sure what their bladders are made of. There are probably six different possible materials and if they use laminates theis complexity increases. Judging from the high quality of Nalgene products I strongly suspect that they use some sort of laminate material. A lot of bladders incorporate silver-based anti-"funk" material which increases the difficulty of recycling.

3. Bisphenol A...estrogen mimic...blah..blah..blah: My first job out of grad school was looking into this and we found nonylphenol compounds had 1,000-1,000,000 less activity than normal estrogen. Bisphenol is in the smae ballpark. To put things in more perspective, there are naturally occurring chemicals in brocolli that have 1-10 times the activity of estrogen. In a nutshell, this is way overrated. As for the cancer, it like anything else, depends on the dose. The amount of bisphenol A released from such a bottle is miniscule. If you take in more than 20 breathes a day you are getting more toxins.

4. Landfill issues: Percentage-wise, your water bottle doesn't amount to a fill of beans compared to the volume of trash generated. Improperly disposing of a single AA battery is much worse for the environment than tossing away a hundred cracked Lexan bottles. The bottles take up space but they don't poison the ground/water.

Taking everything into account, I've chosen Lexan (PC or polycarbonate) bottles as my main water carriers. I find they last much longer than the HDPE bottles. My HDPE bottles became brittle and developed cracks while the Lexan bottles still look brand new. I used bladders for a few years but after two leaked (one Camelback and one Walmart brand) leaving me without water I switched back to Lexan. They are a little heavy and less convinent, but in Texas you don't want to loose your water!

In my humble opinion, the most environmentally friendly water bottle would be some sort of aluminum container. From recycling they come, to recycling they go. You can boil water in them. They are fairly light, but the can be smashed pretty easily. Also, I don't know of any with a mouth big enough for ice cubes (important in Texas).

Like everything else, there's no real "best answer", just assorted trade-offs.

-Blast