Foam testing being carried out at Woodbourne. Photo: Supplied
Toxic 'forever chemicals' have been detected at levels four times higher than guidelines in groundwater at Woodbourne Air Force base near Blenheim.
The Defence Force carries out ongoing monitoring of PFAS levels near Woodbourne and some other bases, such as Ohakea, where firefighting foam has led to long-term contamination.
Most samples at Woodbourne were under human health guidelines.
But at one monitoring bore at the eastern edge of the base, levels were over four times higher in 2023 tests and again in June this year.
The result was for two compounds called PFHxS and PFOS, added together, which is the common way of testing.
"The NZDF continues to conduct long-term monitoring to understand the behaviour of the PFAS plume, and we know from this monitoring over a number of years that PFAS concentrations in groundwater change with seasonal changes (such as severe weather events) and it is not unusual to see PFAS levels rise and fall as a result," the Defence Force said.
Defence bases in the United States and Australia have been the subject of protests and lawsuits over mass contamination, generally at levels much beyond those found in New Zealand so far.
However, local and overseas testing is only able to detect a tiny fraction of the thousands of manmade PFAS, some of which are now found in water, dirt and human blood virtually everywhere on earth.