They say people should avoid gathering food such as watercress in the area and anyone who lives near the airport and who does not tap into the city water supply should be careful.
The city’s water supply is unaffected.
* Testing shows surface water and soil contaminated near Palmerston North Airport * Testing for contamination begins at commercial airports after banned firefighting foam found * Toxic foam found in fire trucks and storage at three more commercial airports * Nationwide investigation into toxic firefighting foam launched​ Horizons Regional Council chief executive Michael McCartney said the next step was to do further testing to determine the extent of the contamination.
"The key thing for us next is to find out how far it’s gone.
Officials were doing work to identify if there was any groundwater in the area or shallow bores.
"The indication is there’s not many, if any."
Testing began in December at Ōhakea and Woodbourne military bases after it was revealed high levels of the chemicals from firefighting foams had contaminated nearby water supplies.
The problem has since spread.
Samples were taken from land at Palmerston North Airport earlier in the year after it was confirmed foam containing banned chemicals was found in fire trucks and in storage at the airport, as well as at airports in Napier and Gisborne.
"We moved pretty quick and getting it right’s really important and if it takes a day or two that’s the wise thing to do."