Plastic pollution in Lake Rotorua similar to lakes in Europe and US - study

A global study has found plastic pollution in Lake Rotorua is similar to lakes in Europe and the United States where the population around the shore is much higher.

Seventy-nine researchers from the Global Lake Ecological Observatory Network (GLEON) contributed samples for the study of 38 lakes across 23 different countries and six continents.

University of Waikato Associate Professor and freshwater ecologist Dr Deniz Özkundakci, one of the authors of the paper, said it was "disappointing" the study found high levels of plastic pollution in New Zealand lakes.

He told First Up that unsurprisingly humans are the reason behind plastics getting into our lakes.

"A lot of the particles were broken down from larger plastic products and lots of products that we generally consider as easily recycled."

The study measured levels of small plastic particles, so microplastics through to macroplastics measuring a maximum of 10mm in diameter.

"One of the more alarming results was the first data showing plastic pollution in some lakes is higher than the plastic 'garbage patches' in the ocean," Dr Özkundakci said.

New Zealand lakes did not have levels to rival the ocean 'garbage patches' but Lake Rotorua had the highest levels of all the New Zealand lakes in the study.

Its levels were similar to lakes in Europe and the United States, however concerningly, the density of population around Lake Rotorua is a lot smaller than some other significantly polluted lakes from the study.

"However, not a single lake in the research was unaffected by plastic pollution no matter how far it was from human activity," Dr Özkundakci said.

The freshwater ecologist said researchers were still determining exactly how microplastics were affecting animals and wildlife.

But plastic ingestion was top of mind and could cause problems for animals.

Dr Özkundakci believed a more extensive survey of lakes in Aotearoa should now be undertaken to identify problem areas.

"We had three lakes [in New Zealand] included in this global study which is useful for us to get a ... baseline.

"But I think we really should look at this more closely to hopefully highlight some hotspots, which would ideally inform us of ongoing management and awareness of the problem."