Gastro risk is real says US expert

New Zealand should tell tourists about the risks of untreated drinking water, an international expert says.

Dr Steve Hrudey, speaking at the Water New Zealand Drinking Water Conference in Hamilton, said there was nothing stopping another outbreak similar to that of Havelock North in August last year.

‘‘If New Zealanders are willing to take their chances, that’s fine, but tell your visitors.’’

Some 300 international and local experts discussed the Havelock North gastro outbreak at a day-long workshop, attended at Hamilton’s Claudelands Arena yesterday.

The outbreak – most likely from sheep faeces contaminating one of the town’s aquifers – made some 5500 of the town’s 14,000 residents ill, put 45 in hospital and has been linked to three deaths.

The first report from a public inquiry found failings included a substandard knowledge of the aquifer’s risk, ‘‘hands-off’’ water assessors, and a dysfunctional relationship between district and regional council.

Hrudey, a Canadian expert who has contributed to the second stage of the inquiry, said there was a clear aversion to chlorinating water during the inquiry.

‘‘The question is why? If the aversion is based on fear of disinfectant byproducts, then the fear is seriously misguided to the point of being reckless.’’

Hrudey’s evidence for the inquiry included examples of 38 outbreaks, nine of which caused 77 deaths. It shows any water catchment exposed to animals and humans required treatment, he said. As treated water isn’t mandated in New Zealand, Hrudey and his wife, Elizabeth, were boiling their drinking water during their stay.

‘‘The population at large believes they’re living in a beauti- ful environment,’’ he said, sparking a knowing laugh from the audience.

Handing water management to local government, the smallest and least funded, proved to be problematic but a national solution was difficult to implement.

‘‘You can have cheap water, you can have safe water, but you cannot have cheap, safe water,’’ he said. The implementation of water safety plans – required by law from water suppliers serving more than 500 people – was central to the day’s discussion.

Ministry of Health data for the year 2015 to 2016 shows 92.8 per cent of the population is covered by implemented water safety plans, but only 80 per cent of New Zealand households receive water that meets the ministry’s standards.

Opus Consultant environmental scientist Jim Graham said the hundreds of water safety plans written had considerably reduced risk in water supply. But the plans were too often concerned with complying to rules, and not on actively reducing the risks in water supply that caused illness.

The plan for Havelock North was wrong to call the affected aquifer ‘‘secure’’, he said, considering it identified the potential risk of the Mangateretere stream causing contamination.

‘‘The approach was to demonstrate the water supply was safe, rather than ask the question: is this water supply safe?’’

Hawke’s Bay DHB medical officer of health Dr Nicholas Jones said water from the affected bore in Havelock North was now treated and regular meetings between the council’s drinking water team and suppliers now take place.

‘‘There is a perceived value in a chemical-free water system, what it’s based on I’m not sure … certainly there is continuing reluctance on the part of at least one of our water suppliers to have chlorine in the water on an ongoing basis.’’