What's in a Water Bottle?
...apart from the water that is.
According to the International Bottled Water Association (IBWA), in conjunction with Beverage Marketing Corporation (BMC), last year in the USA alone 8.75 billion gallons (33 billion litres) of bottled water were bought, and the vast majority of that was sold in single-use plastic bottles. If the average size of a bottle is 1 litre, then we could be looking at 30 billion plastic bottles needing to be disposed of. Extrapolate that statistic across the globe and you start to realize that plastic bottle waste is up there with plastic bags as a serious environmental concern, especially as only a fraction of them are currently recycled.
Outdoors folk have always used canteens and bottles for carrying their water, and along with the gym bunnies, are at the forefront of the growing movement of using reusable bottles in everyday life, rather than just buying branded bottled water in convenience stores. With so many containers on the market, it's good to have a look at the different materials used so you can make an informed choice.
Back in 2008 a number of media reports came out highlighting the possible negative health effects of polycarbonates containing Bisphenol A, or BPA. At the time polycarbontates were used very widely as a plastic film inside beverage cans, and also as the most common material to make rigid plastic water bottles.
BPA was found to be an endocrine disruptor that could mimic the body's own hormones and there are fears that this could lead to health effects, especially in early development, with particular concern for pre-natal development.
Since 2008 more studies have taken place with emphasis put on investigating the effects of constant low-level exposure which more accurately reflects our contact with BPA. These studies have variously found BPA to have an effect on the dopaminergic system, the nervous system and thyroid function, and that it may have an effect on increasing the risks of various types of cancer. These effects have not been categorically proven to have negative consequences on our health, which is why BPA is still being used in beverage cans and water bottles, and why some governments have banned their use in baby feeding bottles, but others haven't.
However, to err on the side of caution, many reusable bottle manufacturers have stopped using plastics which contain BPA as a precaution, and because there are now alternatives.
If you want to read more about Bisphenol A, then click here.
There is an identification system for the resins used to make plastics, and it's useful to know what the numbers mean so you can make an informed choice. For the full list, visit the American Chemistry Council's website here.
In general, plastics with the codes 1, 2, 4, 5 and 6 are unlikely to contain BPA, but some of the plastics marked 3 and 7 could do. This is what the coding will look like on the bottle or packaging for example:
Copolyester (commonly branded Tritan): This is the "new polycarbonate" which produces rigid bottles. It is BPA free but not quite as shatterproof as the old polycarbonate. It's light, durable and doesn't transfer any taste to fluids, nor retain any odours or tastes of liquids held in it.
High-Density Polyethylene (HDPE): This is a semi-rigid plastic and usually quite opaque or cloudy. It's lightweight, durable and generally cheaper than Tritan. It's also BPA free, although it can retain some tastes/odours from flavored liquids.
Low-Density Poylethylene (LDPE): Squeezy bottles are generally made of this, as well as many hydration reservoirs. It's not as durable as the more rigid plastics, therefore more easy to puncture. It's a cheap material and is BPA free.
Polypropylene: A rigid plastic when used to make water bottles. It's super lightweight and fully recyclable as well as being BPA free. It's shatterproof, but could be punctured under extreme force. The material becomes softer when heated, so you might notice this if you're bottling hot liquids. On it's own it can retain odours and flavors but most manufactures use a coating or other such feature to inhibit this.
Generally metal water bottles are made of stainless steel, but sometimes aluminum.
Stainless-Steel: Highly durable, although can be dented. Stainless steel requires no lining and it's unlikely that odours or tastes will be retained. BPA free. Steel is the heaviest of the materials used to make bottles, and if uninsulated will transfer heat more quickly than plastic. Of course, this is sometimes a good thing if you want to use it as a hot water bottle! But they are best to avoid if they are going to be exposed to freezing temperatures for any length of time.
Aluminium: Lightweight and durable. Aluminium bottles (and cans) do need a lining to resist transfer of tastes and odours. Check that these linings are BPA free. Again, like stainless-steel they are not recommended for use in freezing temperatures, but for general outdoor pursuits they are very durable and lightweight.