A first-of-its-kind study into microplastics in Lake Wānaka is underway. 

Marine scientist and PhD student Veronica Rotman is leading the eight-month study, with support from freshwater advocacy group WAI Wānaka.

Very little is currently known about the presence of microplastics - fragments of plastic less than 5mm - in New Zealand’s freshwater lakes and rivers, as most studies have focused on the marine environment. 

“Some chemicals associated with plastics are knowingly toxic to humans, so it’s important to gain an understanding of their presence,” Veronica said.

Microplastics can make their way into the environment through wastewater effluent, stormwater outflow, general degradation of larger plastic products including clothing, synthetic rubber tyres, and even atmospheric fallout, she said.

“They can literally fall from the sky in precipitation, including snow.” 

With the support of WAI Wānaka and a team of volunteers, Veronica is tracking the incidence of microplastics at ten sites around Lake Wānaka.

In addition to the risks microplastics pose to humans, their presence in the environment can have negative impacts on freshwater organisms and taonga species.

“Overseas studies and previous studies I have carried out suggest ingestion by organisms can cause both chemical and physiological impacts, such as intestinal degradation, reproductive issues, neurobehavioural changes, and reduced growth,” Veronica said. 

“They also absorb chemical additives and environmental pollutants that can potentially leach out upon ingestion.”

The local microplastics study will make up a portion of Veronica’s PhD research, titled ‘Ki uta ki tai (mountains to sea): plastics in Southern Aotearoa’, which looks at the spatial distribution of microplastics in southern New Zealand from the mountains to the sea, in snow, water, fish and other organisms. 

“The idea is to determine potential sources, incidence and transport mechanisms of microplastics in our beautiful home, in order to plug the sources,” she said.

It is based on the Māori concept of ki uta ki tai - the recognition and management of the interconnectedness of the whole environment, from the mountains, springs and lakes, down the rivers to hāpua (lagoons), groundwater, wahapū (estuaries) and to the sea.

“Given Wānaka’s geographic location at the headwaters of te Mata-au/Clutha River, locals carry a great responsibility to ensure the wai (water) leaving our rohe (territory) to the ocean is not polluted.”

Veronica said she was looking forward to communicating the findings of the study to the community and “working together to come up with practical and innovative solutions to reduce plastic pollution in our region”.

The local microplastics study, called ‘A Teeny Tiny Truth’, will be completed around March 2024.

PHOTO: Wānaka App