Health Stream Literature Summary - Issue 50 - June 2008

Antimony leaching from polyethylene terephthalate (PET) plastic used for bottled drinking water.
Westerhoff, P., Prapaipong, P., Shock, E. and Hillaireau, A. (2008) Water Research, 42: 551-556.

Polyethylene terephthalate (PET) bottles commonly used for bottled water have been found to leach antimony. Antimony is a regulated contaminant that can cause health effects such as nausea, vomiting and diarrhoea when exposure exceeds that maximum contaminant level (MCL) for relatively short periods of time. Long-term exposure can lead to increased blood cholesterol and decreased blood sugar. Studies have been conducted in Canada and Europe but not in the United States on antimony concentrations of bottled water. This paper compares the antimony content of several bottled waters purchased in south-western US and the effects of storage temperature and exposure to sunlight on antimony release from PET plastic bottles.

Antimony concentrations in nine commercial bottled water brands ranged from 0.095 to 0.521 ppb with an average concentration of 0.195 (+/- 0.116 ppb) when purchased, and 0.226 (+/- 0.160 ppb) after 3 months storage at 22 degrees C. The two bottled water with the highest initial antimony concentrations (Brand 1 and 9) showed statistically significant increases of 25-35% over the 3 month period, the other seven brands did not. A local tap water sample contained 0.146 (+/- 0.002 ppb) of antimony. All of the samples were below the USEPA MCL of 6 ppb.

Brand 9 bottled water was then subjected to a series of further tests. It was found that pH had no effect on antimony leaching at pH values of 6.3, 7.3 or 8.3 when bottles were held at 22 degrees C for 48 hours or frozen. Heating the sample to 80 degrees C for 48 hours increased the antimony concentration from approximately 0.5 to greater than 7 ppb at all pH values tested. After 7 days at 80 degrees, the antimony concentration reached 14.4 ppb which is more than twice the USEPA MCL. Natural sunlight experiments showed no statistically significant changes in antimony concentrations over 7 day.

Antimony was found to leach from the PET plastic used to make these water bottles when water temperatures were above 80 degrees C. In the south-western US the temperatures inside automobiles and garages where bottled water is often stored can exceed this temperature. The authors suggest that bottled water manufacturers need to consider the shipping/storage conditions of the bottled water and if possible choose plastics that do not leach antimony, such as PET made with titanium or germanium rather than antimony-based catalysts.