According to its manufacturer, Nalg Nunc, a popular line of water bottles sold for hiking and other recreational outdoor uses is made of polycarbonate plastic (sold as LEXAN).

http://www.nalgene-outdoor.com/technical/materials/index.html

Recent scientific findings link polycarbonate water bottles to chromosomal aberrations, thus raising questions about the safety of consumer product made with polycarbonate, especially when they are designed to contain food or water.

No tests on bisphenol A leaching have been carried out specifically on Nalgene water bottles, to the knowledge of www.OurstolenFuture.org, nor were Nalgene bottles the brand used in the experiments demonstrating a link between polycarbonate and chromosomal aberrations. There may be some reason why Nalgene bottles do not leach bisphenol A. This would be highly unexpected, however, given their chemical composition.

Details of the research

The research on chromosome damage, by a team of Case Western Reserve scientists, found that bisphenol A leaching out of polycarbonate bottles used to provide water to mice caused a chromosomal error in cell division called aneuploidy. In humans, aneuploidy is the biggest cause of miscarriages and birth defects, including Down Syndrome, that has been identified.

In aneuploidy, cells wind up after cell division with the wrong number of chromosomes. Aneuploidy is thought to be a result of the failure of chromosomes to align properly during a crucial stage of cell division. Biphenol A interferes with chromosomal alignment. The upper, untreated cell has chromosomes aligned properly. The lower cell has been treated with bisphenol A. Chromosomes are scattered throughout the cell. They are unlikely to be properly apportioned to daughter cells during cell division. Photographs from Hunt et al. 2003

More on aneuploidy

The scientists discovered the impact of bisphenol A by accident. A harsh detergent was used to wash water bottles for the mice in experiments exploring why aneuploidy becomes more common in older women. This accident caused an 8-fold increase in the aneuploidy rate in the mice. Subsequent research confirmed that the cause was bisphenol A leaching out of the polycarbonate bottles, and that much smaller amounts of the contaminant were sufficient to increase the rate of chromosomal errors.

More on the accident

Other studies have determined that it doesn't take exposure to harsh detergents to cause bisphenol A to leach out of polycarbonate. The older the plastic is, the faster the leaching rate. Heating also increases the amount of the contaminant that escapes.

These scientific studies have not yet proven with certainty that bisphenol A causes aneuploidy in people. Yet the process of cell division in mice is very similar to that in humans, and scientists suspect that the causes of aneuploidy should be similar if not identical. In addition, a range of earlier laboratory studies already link bisphenol A to other harmful effects, including alteration of the male reproductive tract, hurrying puberty and reducing the effectiveness of prostate tumor treatment.

What is certain is that aneuploidy causes more miscarriages and birth defects in people than any other known factor. Hence the strong evidence linking bisphenol A to aneuploidy in mice suggests that measures to reduce human exposures to this contaminant are now warranted.

In other words, if you have the choice, avoid water bottles made out of polycarbonate.

The laboratory accident also suggests that if you are compelled to use polycarbonate water bottles, then at the very least, do not expose them to harsh chemical conditions. Unfortunately, as of 12 April 2003, that is precisely what the manufacturer of Nalgene water bottles is recommending for its products: washing with bleach when staining occurs (see image below).

As noted above, there may be something unique to Nalgene bottles that makes them chemically different from standard polycarbonate. On the basis of published information, there is no reason to expect this.