Council to probe extent of forever chemicals in Lake Rotorua

The Bay of Plenty Regional Council has approved a one-year investigation after elevated levels of so-called forever chemicals were detected in Lake Rotorua.

While there is no immediate risk to people, officials say the elevated levels could pose a risk to aquatic ecosystems and warrant further investigation.

The decision follows concerns raised last month after testing by Te Arawa Lakes Trust found per- and polyfluoroalkyl substances, PFAS, moving through groundwater into the lake from a former firefighting training area on airport land.

Rotorua Airport phased out PFAS-containing firefighting foams in the 2000s as New Zealand moved away from forever chemicals, but they remain in the ground for decades and have been linked globally with human health concerns.

The trust called for urgent investigation into whether the chemicals were accumulating in fish, shellfish and other mahinga kai species, or traditional food species, harvested from the lake – warning the extent of contamination remained unclear.

At last Thursday’s regional council meeting, councillors unanimously backed a staged monitoring programme expected to cost about $30,000.

Presenting the report, council senior environmental scientist Rupert Craggs stressed the findings did not currently point to a risk for drinking water or people using the lake for recreation.

However, some results were high enough to warrant further investigation.

“We won’t know till we look,” he said.

“There were levels that were found that are a signal of potential environmental or ecological concern to the biota that are living in the lake.”

The programme will begin with a review of existing information before targeted sampling at sites identified as possible contamination sources. If elevated levels are found, more detailed monitoring could follow.

Craggs said the investigation was not intended to focus solely on Rotorua Airport.

Historic use of PFAS-containing firefighting foam at Rotorua Airport's fire training location is reported to be a source of contamination in Lake Rotorua. Photo / File

“This is more around what else might be sources in the lake that we should be aware of,” he said.

Councillor Ken Shirley questioned whether the proposed work would provide a useful long-term baseline for tracking contamination.

“What we want to know in 10 years’ time, has it got better or has it got worse?” he asked.

Councillor Tim Maltby questioned what practical difference the investigation could make if contamination was found.

“If we find it’s there, can we do anything about it or is it just a case of watching it?”

Councillor Sarah McCorkindale suggested contamination could be more widespread than the airport site alone and questioned whether other potential sources across the region should also be examined.

“I think knowing how prevalent this issue is, is really, really critical,” she said.

Eastern Bay of Plenty regional councillor Sarah McCorkindale.

Staff agreed PFAS was likely to exist beyond Rotorua Airport and said part of the investigation would involve considering wider regional sources.

Councillors discussed other options, including a three-year monitoring programme and the possibility of funding PhD research into contamination across the region.

Staff estimated the one-year programme would cost about $30,000, compared with about $90,000 for a three-year study and up to $180,000 if it included a PhD researcher.

Councillors unanimously backed the recommended approach of a smaller one-year investigation, agreeing that the initial investigation would provide a clearer picture of the extent of PFAS contamination before deciding whether further monitoring or other action was needed.

Mathew Nash is a Local Democracy Reporting journalist based at the Rotorua Daily Post. He has previously written for SunLive, been a regular contributor to RNZ and was a football reporter in the UK for eight years.