Tap water in developed countries used to be assumed to be 100% safe to drink, and most water authorities assert that this is still the case. However, there have been an increasing number of studies that throw some doubt into the picture. The problem seems to be that industrialisation (factories and agriculture) generates a range of pollutants that are increasingly finding their way into drinking water.
An example is this 2016 article in the British Medical Journal
“All drinking water should be filtered to remove toxins”
Toxins in tap water include arsenic, aluminium, fluoride, chlorine disinfection by-products.
However, bottled water is not necessarily better, as much of it is actually bottled tap water. In addition, drinking any water from a plastic bottle is hazardous due to leaching of bisphenol A (BPA) which is a hormone disruptor (estrogen mimic) which has been associated with multiple health problems.
To preserve health and prevent disease, all drinking water should be filtered. The best type of filter is a granular-activated carbon block filter, which removes most harmful chemicals and metals.
The US Environmental Protection Agency (EPA) sets these safe limits:
These are some of the limits for pollutants in tap water, and the potential health effects of long-term exposure for adults to high levels. (all units are in micrograms per litre: μg/L)
• Trihalomethanes 80 Liver, kidney or central nervous system problems; increased risk of cancer
• Arsenic 10 Skin damage or problems with circulatory systems, and may have increased risk of getting cancer
• Chromium 100 Allergic dermatitis
• Copper 1300 Liver or kidney damage
• Cyanide 200 Nerve damage or thyroid problems
• Lead 15 Kidney problems; high blood pressure
• Mercury 2 Kidney damage
• Fluoride 4000 Bone disease (pain and tenderness of the bones);
They set many individual limits for pesticides etc., including for example these herbicides:
• 2,4-D 70 Kidney, liver, or adrenal gland problems
• Simazine 4 Problems with blood
But are these limits really safe?
It’s worrying that there’s often a big divergence between what different countries view as a safe maximum.
For example, the US safe limit for Trihalomethanes (by-product of chlorination) is 80 μg/L. Most European countries set a maximum limit of 100, although some are lower, and in particular the Netherlands and Denmark impose a limit of 25.
So, who is right? And what’s to say that further research won’t cause the government agencies to lower these limits in the future?
Perhaps the safest route for us all right now is to take no chances, and to assume that the lowest recommended limits are the ones we should take account of.
And if you want to play really safe, then get yourself a water filter!
Link to my post “Water Filter”