I've got a lovely collection of polycarbonate Nalgene water bottles in an array of colors: sunshine yellow, rosy red, smoke blue, and, my personal favorite, a light greenish-aqua.

It's no exaggeration to say that one of these is always within easy reach, whether it's in my gym bag, on my desk, attached to my bike, sloshing around in my slouchy purse, or beside my bed.

A while back, I remember hearing that these bottles, which are made with Lexan, can leach unwanted chemicals into the water. I didn't heed the warning, though, until a friend -- who happens to be a scientific researcher -- mentioned that she was scared of them.

This didn't sound good.

A quick look around the web revealed that the bottles are made with Lexan [1], a trademarked name for polycarbonate, and that they're made with #7 plastic [1], apparently not a good thing [2]. Thanks to a previous Lime article [2], I discovered that these bottles might leach bisphenol-A, into the drinking water. The chemical is linked to increased risk of birth defects, miscarriage, and cancer. (The article also noted that Nalgene also has a line of bottles in the safer HDPE [3] plastic.)

My search also turned up a number of studies on bisphenol-A [4], along with several highly confusing chemical formulas. Even more confusing are the many conflicting interpretations about any risks. Some say it's dangerous, others aren't so sure. I was in over my head with the word "polycarbonate."

But the bottom line is that I'm looking for a water bottle that doesn't make me nervous each time I take a sip.

Metal bottles seem to be a popular alternative. But I want to be sure about them before I splurge. And I'm also still haunted by the rumor that aluminum is linked to Alzheimers' disease. Again, I don't know if the risk is real, but I'd rather to err on the side of caution.

Two leading contenders are food-grade stainless steel bottles, like these Kleen Kanteen bottles [5]. I'm also totally charmed by Sigg bottles [5]. Apparently, tests show that they don't leach aluminum [6] into the water. It also comes in so many cool colors and patterns, that my inner fashionista is already swooning.

At around $20 each, I'm settled with the fact that I'll never have an impressive collection of Sigg bottles [7]. But one will do just fine.