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Microplastics in Aotearoa New Zealand: local sources and broad impacts

24 May 2024

Impact of microplastics
Microplastics header
Microplastics header

AIM² – Aotearoa Impacts and Mitigations of Microplastics, a five-year Ministry of Business, Innovation and Employment (MBIE) Endeavour Funded project, which concluded this year, has unveiled unsettling truths about the pervasive presence and impact of microplastics in Aotearoa New Zealand. The study highlights the widespread distribution of microplastics and their potential detrimental effects on both the environment and human health.

Microplastics are tiny particles of plastic 0.001 to 5 mm in size. They can be what’s known as ‘primary’ plastic particles, which were specifically designed to be small in size, or ‘secondary’ particles fragmented from larger plastic items. It’s estimated there are more than 15 trillion pieces of microplastic debris in the world’s oceans, 80 percent originating from land-based activities.

Led by ESR’s Dr Olga Pantos and Dr Grant Northcott from Northcott Research Consultants Ltd, AIM² brought together experts from six research institutes and universities, to improve the knowledge and understanding of the level and movement of microplastic pollution in freshwater, marine and terrestrial environments in Aotearoa. They also assessed the risk they pose to organisms and ecosystems and the knock-on effects to our nature-based economy and wellbeing.

The project has produced 40 research articles (with six more in progress), and a range of reports. The following are key findings of the research:

Microplastics found in remote areas

Microplastic particles have been discovered not only in heavily populated areas but on beaches and in coastal waters of some of the most remote regions of New Zealand. This widespread distribution underscores the far-reaching impact of plastic pollution.

Persistence of biodegradable plastics

Polylactic acid (PLA), a common biodegradable plastic marketed as environmentally friendly, remains chemically and structurally unchanged after one year in the sea. This was observed in three distinct locations across New Zealand, challenging the notion that because it's compostable it isn’t a threat to the environment.

Chemical contaminants in marine plastics

Marine plastic pollution collected from beaches around New Zealand is associated with a large number of chemical contaminants. These contaminants pose significant risks to marine life and ecosystems.

Transfer of contaminants to marine life

The study found chemical contaminants from beached plastics can be transferred to animals that ingest them. This raises concerns about the health of marine organisms and the potential implications for the food chain, including humans who may consume the food species that ingest them.

Biowaste reuse and soil pollution

Biowaste reuse practices in New Zealand have been identified as a significant source of microplastic pollution to soils. This highlights the need for better waste management practices to mitigate soil contamination. Whilst ensuring the nutrients in these sources of biowaste are returned to the soil, protecting soil health and function.

Exposure to harmful plastic additives

Organisms that ingest plastics experience greater exposure to plastic additives, including known chemicals of concern. Sublethal effects at the organism level can translate to ecosystem level effects.

Dr Pantos says the research underscores a critical message: “Plastic is a source of pollution at every stage of its lifecycle. The current business-as-usual approach is leading to irreversible damage to the health of our environment and poses a significant threat to human health and well-being. Urgent action is needed to address plastic pollution and protect the natural world for future generations.”

Research produced by AIM²

  • Baettig, C.G. et al., (2024). Characterization of the transcriptional effects of the plastic additive dibutyl phthalate alone and in combination with microplastic on the green-lipped mussel, Perna canaliculus. Environmental Toxicology and Chemistry
  • Li, G. et al., (2024).  Transport and Retention of Sinking Microplastics in a Well-Mixed Estuary, Marine Pollution Bulletin,