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Microplastics
ESR scientists and partners around New Zealand are investigating the impact of microplastics and the threat to our ecosystems, animals and people.
About
Microplastics are tiny particles of plastic 0.1 to 5mm in size. They can be primary plastic particles made for purpose, or secondary particles fragmented from larger plastic items. There is estimated to be more than 15 trillion pieces of microplastic debris in the world’s oceans, 80 percent originating from land-based activities.
ESR scientists have been part of AIM² - Aotearoa Impacts and Mitigation of Microplastic - the first national research programme to investigate the impact of microplastics on Aotearoa New Zealand.
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 MBIE Endeavour Funded programme concluded in March 2024, adding a wealth of knowledge about microplastics in Aotearoa.
Marine plastics
Marine plastics
The type of plastic and the way it interacts with the environment can impact ecosystems and animal health. To understand what is in our marine environment, sea surface and beach sands, researchers ran experiments at different coastal locations around the country to examine the interactions with the marine environment.
In 2020 five different plastics were deployed in coastal waters around Aotearoa, at marine sites in Auckland, Nelson and Christchurch. Held in place by large steel frames, the researchers left the plastics in the sea for a year to see what started living on their surface and what chemicals were released or became associated with them.
Once in the marine environment plastics quickly become colonised by microbial communities, followed by a wide variety of invertebrates and seaweed, until a climax community forms. These communities can be home to invasive species or pathogens of concern, due to the negative effects they can have on the native species.
The researchers monitored the communities over time, using next-generation DNA sequencing methods. They also looked at how they affected the plastics themselves. For example, do the things that grow on them assist with their breakdown and the formation of microplastics?
The five plastics used in the experiment were a mixture of new and artificially aged and included two commonly found in plastic bags (polyethylene and oxo-polyethylene, the latter now banned in New Zealand), one commonly found in drink bottles (polyethylene terephthalate), one increasingly being used in food and liquid containers as a “sustainable” substitute for traditional plastics due to its compostability (polylactic acid), and one used in materials such as fishing lines (nylon). Although polylactic acid (PLA) is an industrially compostable plastic, the conditions required cannot be found in the ocean.
By studying the changes to the plastics over time, and the chemicals and organisms that become associated with them, the researchers can better understand the risks they may pose the environment. And by using artificially aged plastics they can assess how the risks and/or impacts the plastics pose the environment can change as the plastics weather. This is important as we know that there are plastics in the oceans that are just days old, as well as some that are five or six decades old. Only looking at the effects of new plastics does not tell us the full story.
Microplastics Trial Lyttelton
Watch how research in Lyttelton Harbour is helping us understand what happens to plastics in sea water - and what this means for our ecosystems.
Beached plastics
Beached plastics
Researchers including ESR scientists, with help from the Sustainable Coastlines and Litter Intelligence projects, analysed beached plastic debris from 27 sites spanning the length of Aotearoa. The researchers are investigated which chemicals they contained, whether these chemicals were inherent in the plastic or acquired from the environment, and how much of these chemicals were released when they’re ingested by marine organisms.
Results have shown elevated concentrations of many toxic trace elements, such as cadmium and lead. These have been linked with the inorganic pigments used to give plastics their colour and therefore intentionally added (inherent). By simulating the conditions of marine organisms’ gastric fluid, the researchers have also shown that trace elements are released upon ingestion, which demonstrates the exposure of plastic-associated trace elements to organisms.
Freshwater plastics
Freshwater plastics
With a significant amount of plastic pollution entering the environment in urban settings and making its way to the oceans through freshwater channels (rivers, creeks and stormwater) it is important to understand the transition from human use to pollution, and how it affects the plastics’ fate and impact on the environment.
Just like the analysis of marine environments, ESR researchers and collaborators undertook projects that examined plastic at different stages of the freshwater plastic pollution journey. They looked at how microplastics act as a direct chemical contaminant source, absorb contaminants and make them bioavailable, and the microbial interactions involved in these processes.
Read more about the microplastic analyses and impact assessment carried out: Plastics and Te Wai Whau, Tāmaki Makaurau-Auckand.
Metropolitan urban
The Whau River catchment is in Auckland, Aotearoa New Zealand's largest city. The catchment includes urban and industrial areas and contains some of Auckland’s highest levels of pollution from urban stormwater, commercial/industrial site runoff, combined sewage overflows and litter.
Te Hau o te Whau (the essence of the Whau) is a pollution and waste-focused project that brings together groups working across science, community and iwi to help improve the mauri (life force) of the Whau River.
Ecotoxicology and ecological effects
Little is known about the impact of microplastics on dry land. A PhD project by Helena Ruffell within the AIM² research programme explored the impacts of microplastics in productive soils. The project investigated sources of microplastics to the terrestrial environment, focusing on the beneficial reuse of biowastes (effluent, biosolids, compost, vermicast) and their application on to land.
A method was developed to extract microplastics from these mediums, enabling microplastics to be extracted from samples of these different biowastes collected from all around Aotearoa. The impact of microplastic contaminated soil on plant growth was also assessed, with a pot trial of mustard and ryegrass, with oxidative stress biomarkers and nutrient uptake analysed.
Wastewater
Wastewater treatment plants represent a major source of plastics into the environment, as a result of items that are flushed or find their way into this system. Research at the Christchurch wastewater treatment plant by students on the AIM² programme provided an opportunity to examine the impact of this. Their research established a relationship between different plastics and the chemicals and microbes in the wastewater, helping us to better understand the risks microplastics from our wastewater may pose for the environment.
Microplastics in soils: an environmental geotechnics perspective
Microplastics (MPs) are emerging persistent contaminants in the terrestrial subsurface, and evidence has emerged for significant effects of MPs on the biological and ecosystem functions of soils. Main MP sources include land spreading of sewage sludge and biowaste composts, plastic mulching film used in horticultural fields, waste water irrigation and leachate from the landfills, among others. This updated state-of-the-art review paper describes recent experimental and numerical research and developments in understanding the accumulation and fate and effects of MPs in the soil environment (focusing on their storage, degradation, transportation, leaching to groundwater etc.), followed by mitigation and bioremediation measures, including MP-eating soil bacteria and fungi and the best management practices for reducing MP pollution of soil. Other areas covered are the combined effects of MPs and various other environmental contaminants (heavy metals, organic pollutants and antibiotics) in soil ecosystems and the standardisation of methods for detection, quantification and characterisation of MPs in soils, which is critical for MP research. The paper concludes by identifying knowledge gaps and presents recommendations on prioritised research needs.
Fate and impact of nano/microplastic in the geoenvironment — ecotoxicological perspective.
Plastic pollution in the terrestrial environment is emerging as another significant human-made threat to ecosystem function and health. Plastic contamination can range from the macro- to the nanoscale, and environmental impacts are evident at each level. Although significant knowledge gaps remain regarding the interactions between the natural environment and nano- and microplastics (NMPs), there is an increasing body of evidence concerning detrimental effects on a wide range of taxa. The surface properties of NMPs lead to the adsorption of heavy metals, endocrine-disrupting chemicals, antibiotics and other persistent organic pollutants, which, therefore, can result in their co-migration in the terrestrial environment. Although airborne and dietary transmission routes of NMPs have been observed, their effects on human health are still not fully understood, which is of concern to the scientific community. This state-of-the-art review paper firstly examines available evidence for, and knowledge of, various sources of NMP contamination to the terrestrial environment. Attention then focuses on (a) the biological processes from the source to soils and plants, (b) potential impacts of NMPs on soil and subsurface ecosystems, (c) trophic interactions and function and (d) implications for environmental and human health. This paper concludes by identifying knowledge gaps and presents recommendations on prioritised research needs.
Microplastics in the New Zealand green lipped mussel Perna canaliculus.
Microplastics are increasingly being recognised as a potential threat to New Zealand's coastal waters, however there is limited data on abundance of microplastics in marine organisms for New Zealand. Microplastic ingestion by the iconic green-lipped mussel Perna canaliculus was assessed. Microplastics were found in Perna canaliculus from 6 out of 9 locations sampled at abundances ranging from 0 to 1.5 particles per mussel and tissue microplastic concentrations ranged from 0 to 0.48 particles g tissue -1 (wet wt). The microplastics ranged in size from 50 to 700 μm with a median diameter of 100 μm. Polyethylene was the most frequently detected polymer with fragments the most common morphotype. These results indicate that microplastics are widespread in New Zealand's coastal waters and further assessment of microplastic contamination of New Zealand coastal environments and biota is warranted.
Microplastics: impacts on corals and other reef organisms
Plastic pollution in a growing problem globally. In addition to the continuous flow of plastic particles to the environment from direct sources, and through the natural wear and tear of items, the plastics that are already there have the potential to breakdown further and therefore provide an immense source of plastic particles. With the continued rise in levels of plastic production, and consequently increasing levels entering our marine environments it is imperative that we understand its impacts. There is evidence microplastic and nanoplastic (MNP) pose a serious threat to all the world's marine ecosystems and biota, across all taxa and trophic levels, having individual- to ecosystem-level impacts, although these impacts are not fully understood. Microplastics (MPs; 0.1–5 mm) have been consistently found associated with the biota, water and sediments of all coral reefs studied, but due to limitations in the current techniques, a knowledge gap exists for the level of nanoplastic (NP; <1 µm). This is of particular concern as it is this size fraction that is thought to pose the greatest risk due to their ability to translocate into different organs and across cell membranes. Furthermore, few studies have examined the interactions of MNP exposure and other anthropogenic stressors such as ocean acidification and rising temperature. To support the decision-making required to protect these ecosystems, an advancement in standardised methods for the assessment of both MP and NPs is essential. This knowledge, and that of predicted levels can then be used to determine potential impacts more accurately.
Fourier transform infrared (FTIR) analysis identifies microplastics in stranded common dolphins (Delphinus delphis) from New Zealand waters
Here we provide a first assessment of microplastics (MPs) in stomach contents of 15 common dolphins (Delphinus delphis) from both single and mass stranding events along the New Zealand coast between 2019 and 2020. MPs were observed in all examined individuals, with an average of 7.8 pieces per stomach. Most MPs were fragments (77%, n = 90) as opposed to fibres (23%, n = 27), with translucent/clear (46%) the most prevalent colour. Fourier transform infrared (FTIR) spectroscopy revealed polyethylene terephthalate (65%) as the most predominant polymer in fibres, whereas polypropylene (31%) and acrylonitrile butadiene styrene (20%) were more frequently recorded as fragments. Mean fragment and fibre size was 584 μm and 1567 μm, respectively. No correlation between total number of MPs and biological parameters (total body length, age, sexual maturity, axillary girth, or blubber thickness) was observed, with similar levels of MPs observed between each of the mass stranding events. Considering MPs are being increasingly linked to a wide range of deleterious effects across taxa, these findings in a typically pelagic marine sentinel species warrants further investigation.
Comparison of Deposition Sampling Methods to Collect Airborne Microplastics in Christchurch, New Zealand
Airborne microplastics have been identified throughout the Northern Hemisphere in several studies. Synthesising measurements from multiple studies to derive a global distribution of airborne microplastics is difficult because no standard sampling protocol currently exists. Furthermore, measurements from the Southern Hemisphere are largely absent. We undertook a pilot study to test four different deposition samplers and their efficacy in collecting microplastics: a bottle with a funnel attached, an open beaker, a petri dish covered in double-sided adhesive tape and an automatic wet deposition collector. The four samplers were deployed to a suburban site in Christchurch, New Zealand, for four 6-day sampling periods. It was originally hypothesised that the funnel would improve sample retention by limiting resuspension; however, the open beaker was found to be similarly effective. We were unable to assess the effectiveness of the automatic wet deposition collector robustly due to low rainfall during the sampling periods. The adhesive tape sampler proved impractical. Particles collected from all samplers were inspected and classified as microplastics according to a visual screening criteria. Fibres, films, fragments and beads were identified, with fibres being the dominant morphotype (90%); however, only 10% of suspected microplastics were confirmed as plastic following μFTIR spectroscopy. Overall, we recommend the use of a funnel sampler or open beaker for future deposition studies. This is the first study of airborne microplastics in New Zealand and adds to a growing body of evidence as to the widespread nature of microplastics in the atmosphere.
Health risk assessment: Microplastics
Microplastics (MPs) are ubiquitous in the environment. MPs are found in air, water, food and its packaging, soil, and personal care products. Humans can be exposed to MPs through oral, dermal and inhalation routes of exposure. MPs are mainly composed of polymers and frequently also contain additives and plasticisers. The purpose of this report is to review the evidence for adverse human health effects from inhalation, ingestion or dermal exposure to microplastics. It examines previous toxicity studies, including those considering potential in vitro effects. Overall, it found limited conclusive studies (toxicokinetic, toxicity, epidemiology, pharmacology) related to health effects of MPs. Further research is needed, including those that better reflect representatives levels of environmental exposure, and explore potential long-term chronic health effects.
Research expeditions
Research expeditions
ESR researchers have travelled to some of Aotearoa's most pristine spots to gather data about the scale and spread of microplastic pollution.
In 2021 ESR microplastics researchers Dr Olga Pantos and Hayden Masterton travelled to Northland as part of a research voyage bringing together two national collaborative research programmes - the AIM² (Aotearoa Impacts and Mitigation of Microplastics) project and the Marine Biosecurity Toolbox(external link) programme. Scientists from each programme are gathering data about microplastics pollution and assessing the prevalence of invasive pests in New Zealand’s coastal waters.
Collaboration and data sharing between the two projects is key, as plastic can act as a raft for invasive species to arrive in the waters around Aotearoa. Scientists across the two projects are working to identify which organisms tend to interact with different kinds of plastic so that they can make predictions about the threats the marine environment might face. During the voyage, Olga and Hayden collected over 100 water samples to analyse for the presence of microplastics at ESR’s Christchurch Science Centre, as well as delivering ocean literacy outreach work with schools and communities.
In the same year, the researchers also travelled to remote Fiordland to gather more data in some of New Zealand’s most pristine waters, and to consolidate knowledge about the extent of microplastic pollution.
It’s easy to think that anything bigger than 5mm isn’t a problem, but it really depends on the organism or environment interacting with it. The smaller microplastics get, the more they can interact with and in different ways, which is what makes them so hard to deal with. It’s why they can now be found in virtually every part of our planet – including Fiordland.
Olga Pantos
Senior Scientist
Research team
Research team
ESR’s Dr Olga Pantos and Dr Grant Northcott from Northcott Research Consultants Ltd lead the national research programme Aotearoa Impacts and Mitigation of Microplastics (AIM²).
Dr Olga Pantos is a marine microbial ecologist. Since completing her degree in marine and environmental biology she has studied the impacts of anthropogenic (human caused) stressors on marine ecosystems. She was a panel member of the PM’s Chief Science Advisor’s Rethinking Plastics project and on the scientific advisory panel for the UNEA’s Marine Litter and Microplastics Expert Group.
Within the AIM² project her research focus is in determining the levels of microplastics in different ecosystems, and the interactions and impacts of these microplastics on microbial communities which are critical to the health and function of all ecosystems.
Dr Grant Northcott is an environmental analytical chemist with expertise on the fate and effects of organic contaminants in the environment. He leads the contaminant chemistry research within the AIM² project, examining the interactions between the plastic polymers and inherent and acquired chemical contaminants which play a critical role in the risk the plastic poses to the environment.
The research team includes students from the Universities of Auckland and Canterbury. They are looking for the chemical contaminants that become associated with the plastics in the environment, and/or that are released into the environment, the microbes’ ability to fully degrade the plastics, plastics in soils, their sources and impacts on soil health, the effects of plastics on marine biosecurity, plastics in freshwater systems, and potential impacts on the ecology, and the ecotoxicological effects of plastics and their associated chemicals, inherent or acquired.
Meet the team
Name |
Research Area(s) |
Affiliation |
Plastic-microbe interactions |
ESR |
|
Plastic-microbe interactions |
ESR |
|
Dr Pierre-Yves Dupont |
Bioinformatician |
ESR |
Social Science |
ESR |
|
Plastic-microbe interactions |
University of Auckland |
|
Freshwater ecology |
University of Auckland |
|
Marine modeller |
University of Auckland |
|
Marine modeller |
University of Auckland |
|
Dr Louis Tremblay |
Ecotoxicology |
Cawthron Institute |
Marine Biosecurity |
Cawthron Institute |
|
Dr Anastasija Zaiko |
Marine Biosecurity |
Cawthron Institute |
Environmental Chemistry |
University of Canterbury |
|
Social Science and Mātauranga Māori |
Cawthron Institute |
|
Microscopist |
Scion |
|
Polymer Chemist |
Scion |
|
Robert Abbel |
Polymer Chemist |
Scion |
Jamie Brisdon |
Microscopist |
Scion |