I’ll leave the politics out of this one. I’m quite concerned about the “Boil Notices” that the Galway county council have being issuing in relation to the recent contamination of the water supply with cryptosporidium. There are 2 issues at play here and the guidelines provided by the British Columbia Ministry of Health are worth noting. The first is that there appears to be some dispute about whether quick boiling is enough to kill cryptosporidium. I could be wrong here but I’m basing my comments on the US EPA’s statement advising people in affected areas to “bring their drinking water to a full boil for one minute”. From research and querying friends in the US this is often taken to imply stove boiling where the steam, which is hotter than 100 deg celsius boiling water, is effective in killing Cryptosporidium.
So the EPA clearly request a full boil for a one minute period. The problem is that the kettles we use in Europe tend not to boil for a one minute period. They’re efficiently designed to do a 15-20 second boil. Watch your kettle the next time your boiling water for tea and see when you can observe steam and for how long it lasts. This efficiency is a great energy saver but lessens the effectiveness in killing the pathogen.
If in doubt then a possible solution is to boil the water in a pressure cooker where the higher-temperature steam has a better chance of killing the bacteria. The second is a combination of boiling and (one micron) filters to remove cryptosporidium oocysts. (A human hair is around 50 microns thick for reference).
One of the problems with this pathogen is its resistance to chlorine-based disinfectants. In many cases the amount of bleach required to kill the pathogen would render the water poisonous to drink. Success has been had with Ultra Violet light but this is relatively recent research and isn’t recommended by any government that I’m aware of.
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