The Gore District Council’s water service was stopped between July 18 and 21, when nitrate exceeded New Zealand’s maximum acceptable level of 11 milligrams per litre (mg/L) - but since then nitrate readings have been largely above 5mg/L, a level indicative of pollution and above the maximum advised for pregnant women to protect against pre-term births.
The council provided the data to the Otago Daily Times on request and said anyone could ask for their readings.
However, midwifery adviser at the New Zealand College of Midwives Claire MacDonald said the approach was not good enough.
There needed to be an easy way for women to check readings, for example through an online dashboard, ‘‘particularly when there is a compromised supply like in Gore’’.
‘‘You cannot make an informed decision about your health if you don’t have access to the information.’’
The Gore data showed that between July 22 and November 3, 25 out of 31 nitrate readings were above 5mg/L. Some were significantly higher.
Levels rose to 9.79mg/L on October 8, followed by a two-week data gap.
On October 24, when high winds resulted in a declaration of a state of emergency, the level was 9.58mg/L.
Readings for the rest of October were all 7mg/L or higher.
Ms MacDonald said the advisory maximum of 5mg/L for pregnant women was due to advice from well-respected epidemiologists. Women had a right to know nitrate levels when making decisions during their pregnancy ‘‘alongside the many other health-related decisions they make to protect themselves and their babies’’.
A large New Zealand epidemiological study of the link between nitrate and pre-term births is about to be published that has compared birth records and nitrate levels in mothers’ drinking water supplies.
Lead researcher University of Canterbury Associate Professor Tim Chambers could not comment on the results, as they were being peer reviewed, but he agreed it should be a government responsibility to provide the public with accessible and up-to-date information about contaminants in council-supplied water.
Taumata Arowai, the water services authority, should publish drinking water quality data using information from all water suppliers, he said.
‘‘We have advocated this for a long time... Lots of other countries do this; you can type in your address and it takes you to the supply you are on and the latest readings.’’
A digital map by Greenpeace, called ‘‘know your nitrate’’, contains nitrate readings across the nation but they are from various dates.
A reading taken in Gore this week by the environmental organisation was 4.8mg/L.
Greenpeace spokesman Will Appelbe supported the call for Taumata Arowai to make water contaminant levels readily available rather than leave the task to a charity.
‘‘It’s unacceptable that pregnant people are unable to access this information easily in a public forum and are being unknowingly exposed to this increased risk.’’
He also called for a transition from intensive dairying, which academics say is a primary cause of nitrate in drinking water.
Council general manager critical services Jason Domigan said the council took the advice for pregnant women about nitrate ‘‘seriously and remain[s] committed to public safety and transparency’’.
During the state of emergency, the council had taken a ‘‘precautionary approach and informed the community as nitrate levels began to rise’’.
The council’s social media posts on October 25 said residents could stop using council water ‘‘if you are pregnant or have concerns’’.
However, other statements it issued on October 26, about a reading above 7mg/L, do not mention risk in pregnancy and Mr Domigan is quoted saying ‘‘Gore’s drinking water remains safe’’.
The council is working to blend water from more sources to reduce nitrate levels, including constructing two pipelines beneath the Mataura River that will connect Jacobstown bores and the Hilbre Ave reservoir to the East Gore water treatment plant by the end of the year.
The council did not answer questions about why it did not publish all its nitrate readings online, nor announce when readings tipped above 5mg/L, nor issue a precautionary notice on October 8 when nitrate levels were even higher than during the later state of emergency, nor have data readings for two weeks after that date.
Taumata Arowai did not answer a question about whether or not it was planning a water quality portal, fed by council data.
Its head of operations, Steve Taylor, said the agency was ‘‘committed to lifting public visibility of contaminants’’ and reviewing available information but local water providers should inform people of any ‘‘elevated risk’’.
