Following consultation with private bore owners, ground water samples were taken from 12 properties predominantly located to the north and west of the Airport, who have some reliance on bores for drinking water.
All 12 samples complied with interim drinking water guidelines (set at 70 parts per trillion). Eleven samples failed to detect any trace of per- and poly-fluoroalkyl substances (PFAS) at concentrations above the limits of reporting (1 part per trillion).
A groundwater sample from one private bore indicated the presence of perfluorooctane sulfonic acid (PFOS) at 1.2 parts per trillion (just above the limit of reporting), but 58 times lower than the interim drinking water guideline value (70 parts per trillion).
Palmerston North Airport Limited’s (PNAL) chief executive David Lanham says “we are now in the process of informing the 12 households of the good news that their bore water is safe for drinking.”
Horizons Regional Council strategy and regulation group manager Dr Nic Peet says PNAL is to be commended on their proactive approach. “Horizons will continue to work with PNAL, Palmerston North City Council, and the All of Government Group to ensure the sharing of information and communication with all stakeholders is timely and transparent,” says Dr Peet.
Soil values detected on site were all below the human health screening values for industrial/commercial land-use.
Sediment sampling from streams detected PFAS in the northern stream and southern drain but not in Mangaone Stream flowing through the city. Sediment is material that settles in the bottom of drains and streams.
Surface water was also sampled. This is water that collects on the surface of the ground in drains, streams and lakes as opposed to groundwater that travels through aquifers below ground. Surface water sampling did detect PFAS including in the Mangaone stream, however at low concentrations.
PFAS was also detected at ground water sampling sites on airport land.
Further testing is now planned in the northern stream and southern drain, and Mangaone stream adjacent to the airport, to understand whether eels and other aquatic life have been impacted.
MidCentral DHB Public Health Services advises that swimming in potentially affected waterways is not considered to pose a significant health risk.
Ministry for Primary Industries (MPI) notes investigations into PFAS in other countries haven’t reported any welfare impacts on pets or livestock.
MPI reiterates their earlier recommendation that people avoid gathering food such as eels and watercress at the following locations until further test results are available:
- Mangaone Stream.
- Richardsons Line Drain (including its headwater tributaries that cross Railway Road to the east of the Airport).
- Various streams near the Airport flowing through – Madison Ave and Jefferson Cres area, Clearview Park and McGregor Street.
PFAS is an acronym for a group of chemical compounds known as per- and poly-fluoroalkyl substances. They are a class of man-made chemicals that have been used since the 1950s in the production of a wide range of products that resist heat, stains, grease and water, including furniture protectants, floor wax and specialised firefighting foam. PFOS (perfluorooctane sulphonate), PFOA (perfluorooctanoic acid) and PFHxS (perfluorohexane sulphonic acid) are compounds in the PFAS family.