In recent years, Canadians have become increasingly concerned about the safety of plastics and the possibility of them leaching toxins into our food and drinks. The worry has centred around bisphenol A (BPA), a synthetic chemical compound used in polycarbonate hard plastic food and beverage containers. BPA is believed to mimic the effect of the hormone estrogen when found in the body above a minimal level. The effect is particularly noted in babies. Recently, Canada began a move to classify BPA as a toxic substance. The alleged hormone disruptor can be found in hard plastics labeled #7- found in the little triangle on all plastic packaging.
In Canada, BPA is not used in most small plastic bottles that drinking water is sold in. However, it may be present in the polycarbonate used to make the large (18 litre) water bottles used in office and home water coolers.
Most bottled water comes in bottles with the recycling symbol #1. This is polyethylene terephthalate (PET, PETE), which is classified as a safe plastic. No BPA is used to make PET bottles.
One study from the University of Heidelberg has found that PET bottles can leach the chemical antimony trioxide when stored for a long time, even at room temperature. Antimony can cause headaches, dizziness and depression at high levels but is not classified as toxic. These findings have not been confirmed by other researchers and the Canadian government is now looking into antimony.
The PET plastic used to make small water bottles (2 litres and below) is designed for one-time use only. These bottles are very difficult to clean. Bacteria easily gets inside these bottles and you can end up drinking contaminated water. Even if youre filling the bottle with filtered or good quality tap water, contaminants get inside the bottle from your hands and anything else thats touched the bottle.
As well, since plastic is a permeable substance, oxygen, bacteria and anything else in the air can pass through it. The thinner the plastic, the less barrier it offers to substances that can pass through it from the air.
Bacteria can also grow inside unopened bottles if theyre stored for very long periods of time, especially in warm conditions. Health Canada recommends refrigerating small bottles of water once you open them, and ideally when you first buy them. Check the best-before date on your bottled water. For emergencies, you might wish to store water for long periods. Keep these bottles in a cool, dry storage location and use them up after two years.