Current public health warnings and alerts
Immediate chlorination of Napier water
Napier City Council Media Release Tuesday 23 May 2017
Chlorination of Napier City’s water supply will commence today (Wednesday 24 May) at 8am after a positive e.coli reading was returned late today.
Following Napier City Council’s positive result in February of this year, the water team switched from standard testing, which can only return either a positive or a negative result, to more accurate enumerated testing, which gives a reading of between 0 and 10. The level detected in Napier water was measured as a 1 – the lowest level determinable.
However, having experienced a number of transgressions since February, NCC, with the full support of the Hawke’s Bay District Health Board, took the decision tonight to urgently begin a programme of chlorination first thing tomorrow as a precautionary measure.
“We take this matter extremely seriously and feel that the responsible thing to do is to chlorinate the network for a period of weeks,” says Mayor Bill Dalton. “In the past, we’ve successfully isolated and chlorinated particular reservoirs. This time we will chlorinate widely, and for up to a month, in order to eliminate whatever bugs are affecting our water.”
All of Napier, with the exception of Otatara and Puketapu, will be chlorinated. That means that the smell or taste of chlorine may be detectable in the water in Taradale, Bayview and the central suburbs of Napier from Wednesday afternoon onwards.
Napier City Council’s Manager Asset Strategy Chris Dolley stresses that no boiling of water is necessary. “We understand that residents may feel nervous, especially in light of previous water issues around Hawke’s Bay, however we are confident that we are dealing with this positive test in the best way possible. We are appealing for patience and understanding as we work through this process.”
The DHB is reporting no increased incidences of illness.
Napier is one of the only residential water supplies in New Zealand that is not chlorinated. “Most of New Zealand drinks chlorinated water as a matter of course and as their supplies are treated, they don’t get positive readings for bugs like e.coli,” says Mr Dolley. “Here in Napier it’s a different story and with the benefits of untreated water comes a degree of risk. Having said that, having such a high number of transgressions has come as a surprise to us all and along with this period of chlorination, we’re rolling out a series of planned improvements to the entire water network, starting tomorrow.”
The improvements will concentrate on modifying or completely overhauling the testing points – the places where water is drawn for regular testing – as these sites can be sources of contamination, resulting in positive tests. In the meantime, a secure chlorine dosing site is to be established in Taradale, injecting chlorine into the reticulated system 24 hours a day, for as long as is needed. Mr Dolley says it is a massive effort requiring a great deal of resource, however Hastings District Council is assisting with equipment, and that health and safety and logistics are all on track for an early start tomorrow.
Rigorous daily testing will continue and schools, businesses and tourism operators are being notified of the chlorination. A chlorine-free tap, drawing water from the unaffected Otatara and Puketapu area, will be established as soon as possible. Napier residents can expect regular water updates via Facebook, radio and newspapers, and other channels as the chlorination programme continues.
Cyanobacteria confirmed at Lake Tūtira
Water test results from Lake Tūtira have confirmed a cyanobacteria bloom on the lake.
Medical Officer of Health Dr Nicholas Jones said as the bloom was visible on the lake and test results had confirmed cyanobacteria, the bloom was likely to be toxic to people and animals.
Warning signs were permanently in place but people were urged to avoid contact with the lake water and to keep animals away while the cyanobacteria were present.
Hawke’s Bay Regional Council would continue routinely testing the lake, which would provide a good picture of the health risk posed by cyanobacteria, Dr Jones said.
Eating fish from the lake should also be avoided as fish can accumulate toxins from the bloom in their gut. If people did choose to eat fish from the Lake they should make sure all the gut and liver was removed and the fish was thoroughly washed before cooking.
WHAT ARE CYANOBACTERIA?
Cyanobacteria are single celled creatures that live in water environments. Cyanobacteria have characteristics in common with both bacteria and algae. In warm nutrient rich conditions free-floating cyanobacteria cells can multiply quickly to form what are known as algal blooms.
Large numbers of Cyanobacteria can also grow as mats on river and lake beds and these mats can sometimes detach and float to the surface. Some cyanobacteria species produce toxins (cyanotoxins), which pose a risk to humans and animals when consumed in drinking water or by direct contact during recreational activities.