Simplicity versus advanced complexityLet's share data to see whether our drinking water is clean enough

What is healthy and safe water?

Wednesday morning two workshops focussed on this question. In the first session Rhodes Trussel stated that according to his law of decreasing detection limits we will soon break the 1 picogram limit for some contaminants. Question is whether contaminants detected at this level have any actual health relevance. Knowing that the average risk of cancer is 25%, is an increase of 0.000001% relevant? To the public it can be a very relevant topic as they want ” water in it’s natural state”. Norovirus is a ” natural contaminant”. A norovirus concentration of 1 particle per litre (10^-20 g/l) is likely to cause serious gasteroenteritis with potential risk of infecting family members. So from a scientific point of view norovirus poses a much more relevant health risk, but seems less of a concern to the public. Water suppliers are now discussing how far they should go with water treatment to make it safe from a consumer perspective. This discussion was continued in the second session, which focussed on health based investments. Keeping consumer trust may increase the water price by a few percent, but consumers who turn to bottled water would increase their cost by tenfold. The industry therefore needs to send out a clear message that politics determine what ‘safe’ water is and that the water utilities are providing this at affordable costs.

Patrick Smeets

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