Some test sites at the Ohakea airforce base show the level of toxic chemicals used in firefighting foam is on the rise. File photo. Photo: 123RF
Toxic "forever chemicals" are persisting in water around the Ohakea airforce base, with tests showing levels are rising in some cases.
PFAS - per- and polyfluoroalkyl substances - from firefighting foam used on the base was discovered by the Defence Force in groundwater used for local drinking water supplies in 2017.
Bottled water was driven in from 2018, and in 2022 a $12 million piped water scheme opened.
The man-made chemicals persist for centuries in nature and the human body. They can increase the risk of some cancers, push up cholesterol, impair immunity and delay children's development.
Regular tests run around Ohakea detected PFAS in seven bores above the drinking water standard.
At the worst, it was 2-3 times above the higher levels and rising steadily on the base's southern edge, although another bore nearby returned low levels.
"Concentrations for the November 2023 monitoring round are within the historical ranges," the 200-page report from consultants for Defence and the regional council said.
Ohakea airforce base Photo: RNZ / Richard Tindiller
The tests also found it in some spots for the first time.
The main plume extends a kilometre towards southwest from the base, under public and private land. Defence bought up at least one neighbouring polluted farm at a premium.
Reports in 2019, paid for by the Defence Force, said in the worst case the plume would persist for more than a century, spreading at a rate of 50-100 metres per year.
PFAS is also in groundwater near defence bases in Devonport and Whenuapai, although "groundwater from each of those bases drains directly into the sea at Waitemata Harbour" and was not monitored, the Defence Force said.
Testing is continuing at Woodbourne near Blenheim, another contaminated site. RNZ has asked for the results.
The Defence Force faces funding constraints on upgrading its facilities - with $200m of upgrades at Ohakea on ice.
But it said these constraints "are not impacting PFAS monitoring, water supply or wastewater upgrades at camps and bases".
Global testing shows nearly everyone on earth has PFAS in their blood, in at least trace amounts.
It costs a great deal to get the chemicals out of the water. In the US, major polluter 3M has agreed to pay up to $20 billion to settle claims from about 12,000 public water systems across the country.