Scientific research demonstrates that chlorine does not provide effective protection from protozoa such as giardia and cryptosporidium.
This is a major flaw in the Government's proposal to impose mandatory chlorination on all drinking water supplies throughout New Zealand.
While chlorine will kill some of the bugs some of the time in some parts of a supply network it does not provide the protection claimed by the council's consultants in their report tabled at Napier City Council on March 25, 2021.
The council's Water Safety Plan acknowledges that chlorine does not eliminate protozoa and a boil water notice would be required if giardia or cryptosporidium were ever found in the network.
Scientific studies demonstrate that water quality testing for coliforms or E. coli that are very sensitive to chlorine may give the impression that the water is not contaminated, when in fact highly infectious pathogens that are more resistant may actually be present in the water having survived the chlorine.
This is of particular importance in samples taken after repairs and maintenance.
The consultants' plan to reconfigure the whole of Napier's network with all bore water redirected through the reservoirs so it can be chlorinated in expensive treatment plants is a pointless exercise and a waste of ratepayer funds, in my view.
Napier's drinking water is sourced from the secure confining layers of the Heretaunga Aquifer and according to council staff this pure water requires no treatment before it gets distributed.
It is therefore a mystery why the council added chlorine to the pipe network on a permanent basis in May 2017 long before any directive from the Ministry of Health.
Even if it were possible for a contamination event in Napier like they had in Havelock North with 1600 sheep in the paddock next to their bores it is very likely that all the reactive chlorine would be consumed almost immediately.
This is because disinfection with chlorine is a third order reaction (dissolved metals and organics react with chlorine first), leaving little or no free available chlorine (FAC) for disinfecting the remaining network.
Napier's groundwater had never been permanently chlorinated water until May 2017. Similarly, the Dutch stopped chlorinating their groundwater sources after tests demonstrated the biological stability of their groundwater sources which provided water to half the country.
Their river water is another story, however.
After 1975 the Dutch government spent billions of dollars developing a method to purify river water so they could provide safe drinking water to the rest of the Netherlands.
However Napier does not need to spend that money – our artesian water is from the secure confining layers of the aquifer so why would we spend millions estimated by the consultants - just to end up with permanently chlorinated water in Napier – when we could achieve exemption from mandatory chlorination, probably for a lot less.
Going chlorine-free should be no more expensive than the permanently chlorinated option.
The Netherlands can proudly boast that their water is not only safe and healthy to drink but also tastes good.
Pauline Doyle is spokesperson for Guardians of the Aquifer, a lobby group advocating for safe healthy chlorine-free water
