Drinking from plastic bottles: Just how big is the problem really?

The bottle in the sun

A hot summer’s day, the bottle is stuck in its holder, the sun is beating down. What sounds like a good idea – warm water for when you’re out and about – is, chemically speaking, rather undesirable. This is because heat accelerates a process that happens anyway: plastic releases substances. Exactly how many, which ones and in what quantities depends on the material – and is often simply unknown, because manufacturers are not required to specify either the type of plastic or the additives.

Hundreds of substances, little knowledge

Researchers at the University of Copenhagen have shown that hundreds of different chemical compounds can leach into water from new plastic cycle bottles. Scientists do not yet know whether most of these are toxic, or to what extent. What is known is that older or cheaper bottles may contain plasticisers such as bisphenol A (BPA), which can disrupt the endocrine system. Added to this are microplastics – tiny particles that are released through wear and ageing and are ingested along with the water. They can even be detected in the blood. Incidentally, the same issue applies to plastic chopping boards in the kitchen!

The issue of germs in cycling

When you’re out cycling, you handle your bottle with dirty hands; mud splatters onto the mouthpiece, and perhaps there are even splashes from the cowpat you’ve just ridden through. Dust settles on it. The bite valve or pull-tab on a typical cycle bottle is therefore a breeding ground for bacteria and fungi. Isotonic drinks and juices make it even easier for germs to thrive. In short: cycle bottles are put under greater strain in cycling than anywhere else – and it shows.

What really helps

The good news is that there are simple measures that can significantly reduce the risk.

• Select material: Stainless steel and glass do not release any chemicals or microplastics, are tasteless and easy to clean. The first choice whenever possible.
• Look for BPA-free products: Anyone using plastic should avoid polycarbonate (PC) and polystyrene (PS) and insist on products labelled ‘BPA-free’.
• No heat, no fat, no alcohol: These three significantly speed up the transfer of chemicals – so don’t pour hot liquid into your cycling bottle.
• Clean regularly: After every ride, rinse it out, unscrew the mouthpiece, clean it thoroughly – and store it with the protective cap on if possible.
• Replace in good time: Cracks, brittleness or a strange smell mean: bin the bottle. Germs settle in the cracks, where they can no longer be reached by washing.

The conclusion

Plastic bottles aren’t acutely toxic. But if you drink from one every day, for years on end, in the summer, with chilled drinks – you’ll end up consuming more than you might like. Stainless steel is simpler, more hygienic and more durable. For those who still prefer plastic: keep drinks cool, keep the bottle clean, and replace it regularly. It’s as simple as that.