A study of Dunedin fish has found they're consuming surprising levels of microplastic, compared to other parts of New Zealand, or even the world.
Researchers from the University of Otago's marine science department compared fish living near the inner city with their rural counterparts - which came up with some unexpected results.
"It was a really interesting number we landed on. For Dunedin city fish it was around 24 particles, which is quite high compared to other places in New Zealand and around the world," Dr Bridie Allan shared.
Samples taken from isolated parts of Otago found the same species of common triplefin had nine times less microplastics.
It's thought the local landscape could be to blame.
"Dunedin and Otago in particular are exposed to some interesting oceanography - there's lots of really interesting currents which move off the coast," Allan said.
Science leader for the Institute of Environment, Science and Research (ESR) Olga Pantos said "sadly, it's not too surprising" microplastics are being seen everywhere.
The study focused on three sites across Otago - which all differ in human population.
Tests were taken from fish near the City Centre, Port Chalmers, and the Pūrākaunui inlet.
"There's high retention time of water in the inner part of the harbour, which means pollutants and other chemicals have the chance to build up," Allan explained.
Despite the number of global studies into the matter, there's still little known about the way humans and nature are affected by microplastics.
"The triplefin used in this study, that's an important prey choice for larger fish such as blue cod, who will also be exposed to those plastics if they eat that item," Allan said.
"The research is ongoing, and it's a tricky thing to be testing as well. There's consensus it's not good," Pantos added.
It may not yet be fully understood, but it's an issue becoming harder and harder to avoid.
"There is currently no evidence to support microplastics as a concern for our health through food in New Zealand," said Vincent Arbuckle from the Ministry for Primary Industries.
"However, more research is needed," added Arbuckle, New Zealand Food Safety's deputy director-general.
"New Zealand Food Safety is working closely with international colleagues to address data gaps, to determine the occurrence of microplastics in food and to determine whether or not microplastics in food are actually a risk."
