Tuesday, 28 February 2012

Toxic Risk in Water?

Some plastic bottles continuously leach antimony into drinking water, claim geochemists in Germany.  Water contained in PET bottles contained up to 375 ppt antimony, whereas water in polypropylene bottles contained only 8.2 ppt antimony.  Three months later, the water in PET bottles contained up to 626 ppt antimony. PET is made using an antimony catalyst.

The antimony levels in the bottled water are lower than the US environmental protection agency’s maximum contamination level, set at six parts per billion. However, the researchers are more concerned that antimony continuously leaches into the water. However, the results need further scrutiny before any health implications can be discussed, partly because little is known about antimony’s toxicity.

Following reports of benzene in some soft drinks in the US, the Food Standards Agency asked the soft drinks industry to measure levels in the UK.  Benzene is a chemical that can cause cancer in humans. It is present in the air and has been detected at low levels in some soft drinks as a result of interaction between the preservative sodium benzoate and ascorbic acid (Vitamin C).

The Agency has received results of tests for benzene carried out on 230 drinks on sale in the UK. The results indicate that, where detectable, the levels of benzene are very low and are not a concern for the public health. The FSA is continuing to investigate and will be encouraging industry to make levels as low as possible.
Ozone is a powerful chemical reactant which needs special care.  A recent example has been the incidence of high bromate levels in remineralised reverse osmosis water, following ozone treatment, which converted bromide impurities in the salts to the toxic bromate.  

The lesson to learn from all this is that even minute amounts of impurities could be a possible health risk and these impurities can often form dangerous materials by subsequent chemical reactions.

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