Ask the experts: Reusing plastic water bottles

Q: "I've heard that chemicals can leach from water bottles into the water and cause cancer. Is this true?"

A: No. Some reports have suggested DEHA can leach from plastic soft drink bottles into the water or soft drink, especially when a bottle is reused. But most plastic water and soft drink bottles in New Zealand are, in fact, made from PET which does not contain DEHA (check the bottle if you're not sure).

While current research indicates chemicals are not released into water when a bottle is reused, most of these bottles are made to be recycled, not reused. So our best advice is, when reusing a bottle, wash it in hot water and leave it to air dry, and don't use a warped or damaged bottle.

Know your plastics

• DEHA: A food-compatible plasticizer which makes the plastic flexible. Small amounts may migrate into food under certain circumstances.
• PVC: Commercial plastic wraps made from PVC contain DEHA.
• Polyethylene: Plastic wrap we buy for home is usually made from microwave-safe polyethylene.
• PET: Most plastic water and soft drink bottles in New Zealand are made from PET which does not contain DEHA.
• Polycarbonate: A plastic often used in refillable water bottles and baby bottles.