There are two main questions about water that visitors to Tehran ask.
The first one is – can you drink the tap-water?
The second one is – do you drink bottled water?
Let me try to answer them in this order.
On the issue of tap water, in the following, not being an egghead myself, I will try to cut through some of the technical language but forgive me for including some. Sometimes there is no easier way to say something without losing meaning. If anyone wants the detailed technical studies on which I base my comments, please just drop me a line.
So, here we go. 🙂 The only problem with Tehran tap-water is not pollution, per se, but hydrocarbons.The water is safe enough to drink, brush your teeth, and boil up your pasta if you are visiting Tehran. I might even say it is nicer tasting than tap-water I have had in many places, including my home town of Brisbane (which – sorry family and friends living in Brisbane still – after you have been away a while, is a taste that takes some getting used to). In my view, Tehran tap-water has something particular in its taste, and its smell. For example, I have noticed it makes Earl Grey tea taste very odd, and have not yet worked out why that is. For dental health, it is also worth saying that Eau de Tehran has respectable levels of fluoride in all seasons.
So overall, it is not a bad tap water. It is not polluted in the way that term is technically understood by, for instance, the WHO.
However, the one major issue with the Tehran tap-water relates to a thing called polycyclic aromatic hydrocarbons, or PAHs. These hydrocarbons come from human activity. They reach water bodies mainly through dry and wet deposition, road runoff, industrial waste-water, leaching from creosote-impregnated wood, petroleum spills, and fossil fuel combustion. These are a problem because, depending on their levels, they are teratogenic (which, for the layperson, means causing malformations of an embryo or fetus), carcinogenic (which, for the layperson, means causing cancer), and mutagenic (which, for the layperson, increases the frequency – via DNA – of mutations in an organism) and may induce lung, bladder, as well as skin cancer. In addition, exposure to high levels of PAHs has been shown to produce immuno-suppressive effects and is capable of causing oxidative stress during its metabolism.
So, now that you are suitably terrified by this lead up, let’s wrap this up quickly. While the PAHs in Tehran’s tap water have been shown to NOT be polluted according to the WHO definition, this definition is somewhat limited. It does not go far enough, as it only focuses on the concentration of benzopyrene, which is used as an indicator of water pollution. The definition does not, however, take into account the molecular weight of the PAHs found. I am informed, this matters a great deal.
Tehran tap-water’s single-most serious problem is the average occurrence of PAHs with high molecular weights, higher than desirable for human consumption. Cutting to the conclusion of the studies in this area: carcinogen PAHs are present in the drinking water of Tehran in levels higher than those defined by the EU as acceptable, and can cause threats to human health. I am still, however, boiling my pasta in it. Just not making my tea with it. Enough said.
There is not too much research out there about bottled water quality in Iran. One very interesting study, however, was aiming to look at fluoride levels. Incidental to this was an assessment of whether the makers of bottled water were being honest in their flouride content labelling. I know what you might be saying: flouride content alone is not a litmus for water quality. That is certainly true. But if the veracity of labels is a litmus, then this study can be useful to guide us as to water to drink and water to avoid. A good enough guide for me.
It turns out, the bottled water in Iran is overall of good quality and mostly safe. However, there is more than a small amount of falsehood in the labelling. Most bottlers were found to have overstated their flouride content, some dramatically so.
I live by the rule of thumb that if I find someone is telling fibs about the content of their water, drink something else. If truth in labelling is a good consumer indicator, then brands to avoid based on this study include: Damarvand, Damash, and Bisheh. Brands that came out of the study as having the least false labelling (remembering all were at least a little inaccurate, and some – presumably – just plain lies), are VATA, Kouhrang, and Nestle Purelife,
When out and about, or living, in Tehran, it pays to be picky about the water bottle you pick up at the corner store.
So, hopefully this does not put you off your tea. That’s all for now.
Oh, wait, PS: Before anyone tells me about the threat of dioxin in plastic water bottles left in the sun, or frozen, I will tell you this is an urban legend. Purported to be a Johns Hopkins University study, the university denies any such research, and denies any such finding. (http://www.cancerresearchuk.org/cancer-info/healthyliving/cancercontroversies/Plasticbottles/)