Eau, no

In the Oscar-winning movie Slumdog Millionaire, some may have noticed a scene where the brother of the main character is working in a factory illegally 'sealing' used plastic water bottles. The seal we all look for on the lid to ensure it has not been tampered with was being replaced on old bottles to give the impression the water they were selling was from an alpine - or at last a clean - source. It was, however, more likely to be tap water, something you may not want to drink in India. This is not to say that happens - it was a movie after all. But it could happen easily, given the huge number of discarded bottles up for grabs. Which leaves us in developed nations possibly wondering why we don't just drink filtered tap water. It's safe (at the source) and a tap filter can allay your fears about old pipes in some buildings. 'I always suspected that there was absolutely no proven advantage in developed countries of bottled over tap water,' says doctor Nichola Salmond, a GP at Lauren Bramley and Partners. 'Hong Kong water is subject to World Health Organisation recommendations. However, there is always a danger of pipe contamination, so I use a filter.' Salmond says WHO testing is, ironically, much more rigorous than the tests recommended for bottled water. 'The main problem is that, unlike tap water, we really don't know what is in bottled water. Tap water is tested daily and results are available for public scrutiny. There are no similar regulations for bottled and mineral water,' she says. 'Bottled water is stored for longer and subject to heat. It usually has the chlorine removed so contains much higher amounts of bacteria [up to 10,000 times in some studies] than tap water. 'There is a potential danger from chemicals such as phthalates in the plastic storage bottles, not to mention the huge environmental impact of the manufacture and distribution of these.' Which brings us to the problem of poisonous substances. 'Baby bottles and drinking containers made with certain plastics [including some bottled water] leach Biphenol A [BPA],' says Salmond. BPA, according to the Mayo Clinic, appears to cause health problems in animal studies. There has been particular concern about its affect on developing fetuses and infants. 'I would advise parents to use glass or non-polycarbonate plastic bottles,' says Salmond. Eugene Kwan, a family doctor at Central Health Medical, says plastics with BPA have been used for a long time because they're cheap. But Kwan says safety worries, especially over babies' bottles, have led to the development of safer and more expensive plastics that have no known association with cancer, which some brands are now using. 'You also never know how clean any [water] bottles are, either. They go around on these trucks all day and we don't know how long they've been sitting in the sun.' The combination of heat and plastic is a bad one because it's heat that causes BPA and other potentially dangerous chemicals to leach into the water. Kwan says despite there being no firm agreement among professionals on the possible dangers, he uses glass bottles for his children. 'With high temperatures, you never know with plastics,' he says. Not all the experts are worried - yet. The US Food and Drug Administration (FDA), based on an ongoing review of BPA, says: 'We believe there is a large body of evidence that indicates that FDA-regulated products containing BPA currently on the market are safe and that exposure levels to BPA from food contact materials, including for infants and children, are below those that may cause health effects'. However, it concluded that it will continue to 'consider new research and information as they become available'. Views may differ, but retailer Toys 'R' Us in the US announced last year that it would phase out baby products containing BPA. Kwan acknowledges that some plastics are safer for human consumption. Knowing which ones, however, is difficult, so many choose to avoid plastics altogether. 'For my children, we don't use plastic bottles. If we're out, we use glass containers and we filter water for cooking, boiling and drinking,' he says. Salmond says: 'In my opinion, the safest water [in developed countries] is filtered tap water, which also has the benefit of fluorination to prevent tooth decay, [which is] proven to be both beneficial and safe. 'Another factor is cost because tap water is 1,500 times cheaper and in blind tasting appears to have no taste disadvantage over mineral water.' Bottled water also has had its fair share of problems with other chemicals. Hong Kong's Consumer Council recently caused a stir with French brand Perrier, saying high nitrate levels found in a carbonated drink were unsafe. The council said in a statement that 'one natural mineral water sample was found to contain nitrite in the amount of 0.4 milligrams per litre, which was in excess of the limit [0.1 mg per litre] set in the Codex Standard for Natural Mineral Waters'. It went on to say that, according to a joint expert committee on food additives, the acceptable daily intake of nitrite is 0-0.07 mg for every kilogram of body weight. Wan (Corporate Services) Ltd, the sole agent for Perrier in Hong Kong, said in a statement: 'We strongly believe the Consumer Council finding is not correct.' The statement said nitrite levels in Perrier were regularly and closely monitored. Salmond says carbonated water in glass bottles is generally safer. The carbon dioxide leads to lower bacteria levels than still water. 'However, as with the benzene [carcinogenic] Perrier scare [in the 1990s], they can also have undetected contaminants,' she says. Traces of benzene found at the time forced Perrier to change its labelling in the US. In 2007, the Hong Kong government also urged customers to not drink a bottled water called Jermuk Original Sparkling Natural Mineral Water Fortified With Natural Gas From The Spring, after the FDA advised there was excessive arsenic in it. Feeling thirsty? It might pay to save money, avoid environmental damage and get back to basics when it comes to water.