Here is some info from Wikipedia on antimony in PETE plastics (http://en.wikipedia.org/wiki/Polyethylene_terephthalate):

'Antimony trioxide (Sb2O3) is a catalyst that is often used in the production of PET. It remains in the material and can migrate out into food and drinks. The Swiss Federal Office of Public Health compared the amount of antimony in waters bottled in PET and glass: the antimony concentrations of the water in PET bottles was somewhat higher, but still well below the allowed maximal concentrations.[2] (report available in German and French only) The Swiss Federal Office of Public Health concluded that the health risk of these low concentrations is negligible (1% of the "tolerable daily intake" determined by the WHO) ? although antimony is very toxic at much higher concentrations . A later (2006) study by a group of geochemists headed by Dr. William Shotyk [3] finds similar concentrations of antimony in water bottled in PET and, comparing it with concentrations in groundwater and in natural water bottled both in polypropylene and glass, concludes that Sb is leaching from PET. While ground water contains approximately 2 parts per trillion (ppt) of antimony, freshly bottled water averages 160 ppt. Samples left up to six months had levels as high as 630 ppt.'

And from WHO 'Guidelines for Drinking Water Safety'
(http://www.who.int/water_sanitation_health/dwq/chemicals/antimonysum.pdf):

'Daily oral uptake of antimony appears to be significantly higher than exposure by inhalation, although total exposure from environmental sources, food and drinking-water is very low compared with occupational exposure.

'... Conventional treatment processes do not remove antimony. However, antimony is not normally a raw water contaminant. As the most common source of antimony in drinking-water appears to be dissolution from metal plumbing and fittings, control of antimony from such sources would be by product control.

'... Toxicological review -- There has been a significant increase in the toxicity data available since the previous review, although much of it pertains to the intraperitoneal route of exposure. The form of antimony in drinking-water is a key determinant of the toxicity, and it would appear that antimony leached from antimony-containing materials would be in the form of the antimony(V) oxo-anion, which is the less toxic form. The subchronic toxicity of antimony trioxide is lower than that of potassium antimony tartrate, which is the most soluble form. Antimony trioxide, due to its low bioavailability, is genotoxic only in some in vitro tests, but not in vivo, whereas soluble antimony(III) salts exert genotoxic effects in vitro and in vivo. Animal experiments from which the carcinogenic potential of soluble or insoluble antimony compounds may be quantified are not available. IARC has concluded that antimony trioxide is possibly carcinogenic to humans (Group 2B) on the basis of an inhalation study in rats, but that antimony trisulfide was not classifiable as to its carcinogenicity to humans (Group 3). However, chronic oral uptake of potassium antimony tartrate may not be associated with an additional carcinogenic risk, since antimony after inhalation exposure was carcinogenic only in the lung but not in other organs and is known to cause direct lung damage following chronic inhalation as a consequence of overload with insoluble particulates. Although there is some evidence for the carcinogenicity of certain antimony compounds by inhalation, there are no data to indicate carcinogenicity by the oral route.'

Of course, carcinogenity is hardly the only concern with drinking water. For instance, I've never heard of cyanide as a carcingen, but it kills you anyway. <img src="/images/graemlins/smile.gif" alt="" />

Sue