Hot Liquids Dramatically Increase Release of Toxins From Plastic Bottles

by Alok Jha
The Guardian
January 30, 2008

Hot liquids dramatically increase the amount of harmful chemicals released by plastic bottles, according to a study.

Scientists found that polycarbonate plastic bottles released a known environmental pollutant 55 times more quickly when filled with boiling water.

Polycarbonate is used to make everything from compact discs to milk bottles for babies. The plastic is made from bisphenol A, a chemical produced in large volumes across the world. But over time, the plastic leaches its raw ingredient back into the environment.

"There are a lot of concerns surrounding bisphenol A," said David Santillo, senior scientist at the Greenpeace research laboratory in Exeter. "It is a hormone disrupter able to mimic and interfere with hormone systems in animals."

In the experiment, Scott Belcher, of the University of Cincinnati College of Medicine, wanted to work out how bisphenol A leaked out of polycarbonates and whether the temperature of the liquid stored in the bottle affected the rate.

"Previous studies have shown that if you repeatedly scrub, dish-wash and boil polycarbonate baby bottles, they release bisphenol A. But we wanted to know if 'normal' use caused increased release from something that we all use, and to identify what was the most important factor that impacts release," he said.

Belcher took reusable water bottles and tested them for seven days with room temperature water and then boiling water, simulating normal usage during backpacking, mountaineering and other outdoor adventure activities.

He found that boiling water released bisphenol A from the bottles up to 55 times more quickly than the lower-temperature water.

The results, published in the latest edition of the journal Toxicology Letters, found that with room temperature water the rate of release from individual bottles ranged from 0.2 to 0.8 nanograms of bisphenol A an hour. After exposure to boiling water, rates increased to 8 to 32 nanograms an hour.

"A nanogram is a fairly small amount but, given that a lot of hormones work at levels far below that, even if it's not as potent as a natural hormone, you are in the range there which could be contributing to adverse effects," said Santillo.

He added that Belcher's research should renew calls to develop alternative materials for baby milk bottles.

"Newborn babies are at a very sensitive stage of their development and the last thing you want to be doing is dosing them with a very potent hormone disruptor," he said. "If there are ways of avoiding that, the time has come for the public to know about those."

© Guardian News and Media Limited 2008

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