Plastics and the environment – life cycle assessment and beyond
The thinking around how plastic impacts the environment often focuses on plastic that has leaked into our oceans due to mismanagement at its end-of-life. Other catastrophic events, such as the recent high-profile failure of a landfill on the West Coast, also bring the issue of plastic in the environment to the fore. There is a growing body of evidence that details the impacts of plastic that has leaked into the environment. While there is no denying that plastic pollution is problematic, it is not the only consideration that we should take into account when deciding whether use of plastic product is sustainable. Plastics do not only have an impact on the environment at end-of-life. Acquiring the raw material to produce virgin resin, manufacturing that resin into a product, distributing the product through its supply chain to end-market, using the product, and disposing of or recovering the materials all require resources and generate outputs that have environmental impacts. Other materials generate environmental impacts throughout the whole life cycle as well. The material that is the least environmentally damaging will depend on context and application – evaluating differences in life cycle environmental impacts in combination with the risks of environmental leakage on ecosystems and the potential health implications of different materials can help guide these decisions. Ensuring that the future production, consumption and disposal of plastics is sustainable aligns to te ao Māori, because it recognises that earth’s resources are finite and that the appropriate use and management of these resources is fundamental to the wellbeing of people, communities and our natural environment. Sustainable use of resources has received growing attention more recently in the Western world view and research community. Other significant learnings from mātauranga Māori that can help shape our response to the environmental impacts of plastic include taking a holistic, systems view of the impact of plastic and embracing the strength of local knowledge and action to observe and remediate environments. The importance of considering the full life cycle of a product was articulated in Plastics and Health: The Hidden Costs of a Plastic Planet by the Center for International Environmental Law (CIEL).
“The narrow approaches to assessing and addressing plastic impacts to date are inadequate and inappropriate. Understanding and responding to plastic risks, and making informed decisions in the face of those risks, demands a full life cycle approach to assessing the full scope of the impacts of plastic on human health. This includes to ensure that we are not creating yet more and increasingly complex environmental problems in attempts to address this one.”
The life cycle of plastic from resource extraction of raw-material feedstock to end-of-life disposal and possible re-entry into the use cycle. Leakage into the environment is a potential end-of-life scenario. Adapted from Plastics Europe. Click here to download the image.
Reducing emissions from plastics
Plastics contribute to climate change across the whole life cycle – from the extraction of fossil fuels as feedstock for plastics through to the climate change impacts of the end-of-life option for plastic waste. A comprehensive report on the topic, led by CIEL, highlights how plastics produce greenhouse gas emissions across the life cycle.
In brief, emissions occur from:
- Extraction and transport: leakage, fuel combustion, energy consumed during drilling for oil or gas, and land disturbance when forests or fields are cleared for drilling and pipelines.
- Refining and manufacture: the cracking of alkanes into olefins, the polymerisation and plasticisation of olefins into plastic resins, and other chemical refining processes.
- Waste management: incineration in the open (extremely high), recycling (moderate – and advantageous because it displaces new virgin plastic) and landfilling (least – but could increase with more biodegradable plastic releasing methane).
- Plastic in the environment: early reports suggest that plastic on the ocean surface and on coastlines, riverbanks and landscapes may release methane and other greenhouse gases, and that microplastics in the oceans may interfere with the ocean’s capacity to absorb and sequester carbon dioxide. Further research is needed to confirm these findings.
At the product level, plastics can contribute to reducing our climate change impacts because plastic is lighter than most alternative materials it replaces. An example is the use of plastic rather than metal in aeroplanes, which makes the plane lighter and therefore reduces fuel consumption. Another example is through net reduction in impact due to food preservation that may be lost with alternatives or the removal of packaging altogether. It is important to consider the climate change impacts of alternatives that could replace plastic products to ensure that rethinking plastics does not lead to a net increase in climate change impacts.
However, while we can look at the climate change impact of individual products, it is actually the overall scale of plastic production, use and consumption that threatens our ability to meet global climate targets. Even conservative estimates say the volume of consumed plastics – which has doubled since the turn of this century – will quadruple by 2050 if no changes are made. With the projected growth in use, plastic is estimated to be responsible for up to 15% of the total ‘carbon budget’ by 2050.
Evidence suggests that the combination of using less plastic overall (e.g. through replacement with other materials or reuse systems), aggressive application of renewable energy, recycling and replacing fossil-fuel feedstock with biomass has the potential to reduce emissions from plastics and achieve an absolute reduction from the current level. 
The place for life cycle assessment in rethinking plastics
Ideally, individual consumer choices, product development and design choices, and policy decisions would all be informed by robust evidence about what is sustainable and best for the environment. That evidence needs to consider a product’s impacts across the full life cycle, including if it leaks into the environment, and not just its end-of-life options. Pragmatically, the information that could help to inform these choices is not widely available or accessible – for example, it won’t be immediately clear to a person making a decision at the supermarket which product has a lower environmental impact. This often forces people to make their decision based solely on end-of-life options (i.e. it is recyclable or not) or preconceived ideas about what is better (e.g. assuming cardboard is better than plastic, without evidence). Life cycle assessment (LCA) can be used to inform choices by evaluating and comparing the full life cycle environmental impact of different options, including different end-of-life options. LCA studies highlight any trade-offs that arise when considering alternatives, and through use of a ‘functional unit’ as the basis for the analysis, enable fair comparisons. It is important to emphasise that there are often no clearly preferred outcomes in comparisons between products made from plastics versus other materials. For example, Product A may have a lower climate change impact but cause more damage to rivers than Product B, so the decision will partly rest on value judgements on the various types of environmental impacts, alongside economics. The preferred product or system will also depend upon factors such as the geographical context, user behaviour, and structure of local waste management systems.
Life Cycle Assessment (LCA) can be used to inform choices by evaluating and comparing the full life cycle environmental impact of different options, including different end-of-life options
The current limitation of relying solely on LCA to inform these choices is that it doesn’t account for the environmental impacts caused by plastic leaking into the environment as litter. To date, some studies have developed separate indicators for litter (read the Case Study) but these are not part of the LCA methodology itself. There are efforts underway to allow integration of the potential environmental impacts of marine litter into LCA results. The Marine Impacts in LCA project is working on a framework paper to illustrate the different impact pathways associated with marine litter, and this is due to be published in December 2019. But the final framework for incorporating marine litter into LCA studies is not expected until 2025.
There are many opportunities to use LCA to quantify the environmental impacts of a product or system and support evidence-informed decisions when rethinking plastics. Here we illustrate the relevance of LCA through a series of key questions:
- Are reusable products always better than single-use alternatives?
- Should we switch to bio-based plastics?
- Is recycled plastic actually better for the environment?
- Should we ban plastic packaging altogether?
- Should we use an alternative material to plastic?
- Should we restrict our use of plastic to certain types?
- What end-of-life options for plastic are best for Aotearoa New Zealand?
Are reusable products always better than single-use alternatives?
For many everyday products, it is possible to buy a single or multi-use option. These may be made of plastic or other materials. Examples include coffee cups, cutlery, shopping bags, razors, food wrap and nappies. Extending this idea further, for other types of products it is possible to buy products that are likely to last a lifetime or to opt for alternatives that are less robust and may break after a few years. Examples include fast fashion versus durable shoes and clothing, and cheap versus robust and well-crafted furniture.
It is often assumed that the most environmentally sustainable product is the multi-use or durable option. Is this really the case? Generally a reusable or durable product uses more material in its production and may have environmental impacts to keep it in use (e.g. the energy required to wash the product). Ultimately, the number of times the durable item is used – and therefore the number of single-use items it displaces – will dictate whether it is environmentally preferable to a single-use product. Accumulating many cotton shopping bags or plastic storage boxes in the cupboard at home and failing to use them is not a good result!
Ultimately, the number of times the durable item is used – and therefore the number of single-use items it displaces – will dictate whether it is environmentally preferable to a single-use product
The key takeaways for life cycle impacts of single-use versus multi-use products are:
- Durable products are likely to be environmentally preferable to single-use disposable alternatives, but only if they are reused enough times to maximise their environmental benefits compared with the alternatives. This is true of plastic and other materials.
- Developing systems where products such as plastic containers are reused could also provide a further benefit in reducing transport-related emissions as less material is transported per unit of service provided by the product to the customer.
- Hygiene and safety issues need to be considered. Factoring in requirements to meet H&S (i.e. washing) may shift net environmental impacts in favour of single-use for some applications, and the risks of contamination may outweigh the benefits in other applications.
- Extending the lifetime of all plastic products is environmentally beneficial in most cases.
- Making reuse the new norm will continue to increase public awareness around resource use and litter, and as people continue to use products as many times as possible it will have environmental benefits.
Should we switch to bio-based plastics?
Moving to renewable sources for materials is an important aspect of establishing a circular economy. For plastics, this involves reducing the use of non-renewable fossil-fuel feedstocks and increasing the use of renewable bio-based feedstocks. Note that bio-based plastics are not necessarily biodegradable and vice versa, and sometimes a bio-based plastic can directly replace the fossil-fuel based counterpart.
As technology advances for the production and use of bio-based plastics, we need to consider whether the environmental profiles of these plastics are better than their fossil-based counterparts, and also whether there are secondary environmental impacts associated with displacement of other activities. For example, potential future feedstocks for bio-based plastics may currently be used as food sources, and the consequence of diverting these feedstocks to bio-based plastic production needs to be considered when determining whether it is a sustainable source for plastics production. Lessons should be learned from the food shortages that have resulted from generating biodiesel. One way to avoid this is by using waste products as a biomass feedstock for plastic materials.
Lessons should be learned from the food shortages that have resulted from generating biodiesel. One way to avoid this is by using waste products as a biomass feedstock for plastic materials
It is also important to weigh up the benefits of switching to a more sustainable feedstock for plastics with the costs of displacing types of plastic that could be recycled, particularly those that can be recycled onshore. The complexity around whether bio-based plastics are better for the environment than fossil-based plastics is illustrated in a Case Study, based on an infographic developed by Kirsten Edgar at Callaghan Innovation.
The key takeaways for life cycle thinking related to bio-based plastics are:
- At present, bio-based plastics are not necessarily environmentally better than fossil-fuel based plastics or other types of materials – it depends upon what the plastic is made from, how it is produced and how it will be managed at end-of-life. Trade-offs should be evaluated using LCA studies. Shifting to 100% bio-based plastics in conjunction with other changes may reduce the carbon footprint of plastics in the future (read the Case Study).
- For bio-based plastics, a systems-based analysis of potential feedstocks is necessary to ensure net environmental and other sustainability benefits. This needs to factor in the full life cycle of the product, including whether it is biodegradable (e.g. PLA) or can ‘drop-in’ to existing recycling processes (e.g. bio-PET (#1)).
- Certain applications of bio-based biodegradable plastics may have co-benefits such as reducing food waste or reducing impacts of litter or plastic pollution, which should be considered alongside LCA findings if not factored in explicitly.
Is recycled plastic actually better for the environment?
Increasing the recyclability of plastic and use of recycled plastic is a fundamental aspect of transitioning towards a circular economy. There is likely to be a marked increase in the use of recycled content in packaging in the coming years because it is one of the commitments in the packaging declarations that many Aotearoa New Zealand businesses and the New Zealand Government have signed. The process of recycling plastic uses a number of resources, each with associated environmental impacts – energy is used to power the machinery to separate plastics, water is used to wash flakes, energy is used to melt separated plastics and form it into nurdles (pellets), and fuel is used to transport recycled plastic to and from recycling facilities. Comparing these impacts against those associated with producing virgin resin can inform how the environmental impacts differ between the two and in which contexts it might be favourable to use virgin versus recycled resin.
The main considerations for the life cycle impacts for recycled versus virgin resin are:
- Recycling plastic is likely to be environmentally beneficial, but there needs to be a demand to use the material. Contamination of plastic waste streams with other materials or with types of plastic that cannot be recycled may reduce the efficiency of the process and increase environmental impacts. The worst outcome is to have the environmental impacts of the process outweigh the benefits.
- The source of energy used in the manufacture and recycling process has a significant bearing on the environmental impacts. The majority of Aotearoa New Zealand’s electricity is generated from renewable sources, so recycling plastic is likely to be environmentally beneficial here. Whether this is true of imported virgin or recycled resin will depend on the energy sources of the country of origin.
- The distance between material collection and recycling facilities will also have a significant bearing on the environmental impacts through energy used for transport. The large transportation distances that may be required due to the low population and limited number of MRFs and/or recycling facilities may increase emissions for recycled plastic in Aotearoa New Zealand. The rail network is unlikely to present a solution given the logistical issues of where waste would need to be transported in order to be loaded onto the network (read the Case Study).
- The source of feedstock is an important driver of the carbon footprint of bio-based plastics.
- The potential health and toxicological impacts associated with chemical additives in the recycled plastic are not factored into LCA studies and must be considered depending on the application of the recycled material.
Should we ban plastic packaging altogether?
An extreme response to reduce the use of plastic and its associated environmental impacts would be to ban plastic packaging altogether. We need to prioritise rethinking systems and reducing our use of plastics, particularly for unnecessary packaging and products. However, before removing plastic packaging, we need to factor in the benefits of packaging that are lost if the packaging is removed and take a ‘whole-of-life’ approach to environmental impacts. One of the purposes of packaging is to protect the contained product, and so its removal may lead to a higher proportion of damaged or spoiled products. Examples include plastic sleeves around cucumbers and other vegetables or fruit to give them a longer shelf life in supermarkets; plastic liners in cardboard boxes of kiwifruit that are traded internationally contribute to keeping the fruit in good condition over several weeks; and packaging around new consumer goods such as washing machines, televisions and furniture that stop these products being damaged in transit. It is important to be aware of the function of plastic packaging when assessing alternatives, and ensure that any alternatives conserve the functionality of the packaging. Some businesses are currently facing pressure from their customers to move away from plastic packaging, but decisions to remove packaging altogether or shift to a non-plastic packaging should be guided by LCA to avoid creating a worse environmental outcome.
Decisions to remove packaging altogether or shift to a non-plastic packaging should be guided by LCA to avoid creating a worse environmental outcome
The key points when considering the life cycle impacts of banning plastic packaging are:
- When considering alternatives to plastic packaging, LCA should be used to investigate any trade-offs in net environmental impacts arising from potentially greater wastage of the packaged product when using alternative packaging.
- An unintended consequence of removing plastic packaging may be an increase in emissions due to food waste.
- A supply-chain approach to reducing use of plastic is needed to ensure removing packaging at one stage (e.g. retail) doesn’t lead to an increase in environmental impacts (e.g. food waste).
- If plastic is necessary for food preservation, it is imperative that systems are in place to maximise that resource staying in circulation and not leaking into the environment.
- It is not simple! Businesses need support to guide their choices.
Should we use an alternative material to plastic?
Public concern over plastic is growing and therefore pressure is mounting on brands to change materials, particularly for packaging. The question of whether to replace plastic with an alternative material such as cardboard, metal, glass or a multi-material option is arising in many businesses. Where packaging is deemed to be necessary, businesses need support to determine what the ideal packaging material is for their products. LCA can be used to inform material choice for a specific application by evaluating and comparing the full life cycle environmental impact of different options, including different end-of-life options. Such an analysis may demonstrate that in the Aotearoa New Zealand context, a plastic bottle made of PET (#1) has lower environmental impacts compared to a glass bottle, or it may indicate the opposite. In general, LCA comparisons should be undertaken at the application level rather than at the material level because these will draw a complete picture of the environmental impacts over the product’s life cycle. This is important because there might be environmental impact hotspots in the life cycle that are more important than the impacts of material production – as illustrated with food waste in this Case Study.
The key takeaways related to life cycle thinking when replacing plastic with an alternative material are:
- Plastic may or may not be the best material choice for a product from a life cycle based environmental perspective – it depends on the context and the alternatives available, and should be assessed using LCA.
- Plastic is lighter than many other materials, such as glass, steel and concrete, and so may be preferred when the environmental hotspots of a product are associated with transportation (e.g. international transport of some food products with plastic packaging, body parts for vehicles).
- Because environmental leakage is not currently factored into standardised LCA methodology, we need to explicitly consider the evidence related to the impacts of plastic leaking into the environment alongside the evidence from LCA. Non-marine-biodegradable plastic is unlikely to be the best material choice for a product where there is a high likelihood that it will leak into the environment after use and end up in the ocean.
Should we restrict our use of plastic to certain types?
For most brands, the cost of manufacturing the product generally dictates material choice but ideally life cycle thinking would be used to guide these choices. Though it is better to perform LCA for an application rather than the material on its own. However, there are many instances, particularly in packaging, where several types of plastic could be used and the main difference in environmental impact comes from the available end-of-life options. Thinking about whether the material can and will be recycled might drive brands to use PET (#1), which has an onshore closed-loop recycling system and a good market for the recycled plastic (read the Case Study), rather than PVC (#3) or PS (#6), which have neither.
Thinking about whether the material can and will be recycled might drive brands to use PET (#1), which has an onshore closed-loop recycling system and a good market for the recycled plastic, rather than PVC (#3) or PS (#6), which have neither
There are other times where changing to an alternative plastic, even one that has an onshore recycling solution, wouldn’t be environmentally beneficial because it would require using more plastic material or using additives that limit future recyclability of that plastic. For example, to effectively store ice cream in a freezer, a PET (#1) container would need far more material than the PP (#5) containers currently used, which are also better suited for products that are hot when packaged.
The key takeaways when thinking about life cycle impacts of restricting use to certain types of plastic are:
- Decisions about restriction of plastic types should be supported by LCA studies of the alternatives that identify any trade-offs in net environmental impacts associated with production and use of alternative materials, recyclability of alternative materials, greater wastage of the packaged product, etc. for the Aotearoa New Zealand context. One implication of restricting to certain types of plastic is that it will funnel use and improve economies of scale for more favourable types, further reducing environmental impacts.
- Considering these factors in the current Aotearoa New Zealand context, the types of plastic with the lowest environmental footprint are likely to be PET (#1), HDPE (#2) and PP (#5) because there is onshore reprocessing capability and a strong market for these materials to be pulled through and used again, which is key for reducing the impacts of the plastic.
In the current Aotearoa New Zealand context, the type of plastic with the lowest environmental footprint is likely to be PET (#1), HDPE (#2) and PP (#5) because there is onshore reprocessing capability and a strong market for these materials
What end-of-life options for plastic are best for Aotearoa New Zealand?
LCA can be used to evaluate the environmental impacts of systems as well as products. It is an alternative approach to the widely cited waste hierarchy framework that is predominantly used to guide waste management policies. The waste hierarchy is based on end-of-life options for a product rather than the whole-of-life environmental impacts considered in LCA, and does not account for the context in which waste management decisions take place. For example, recycling cannot take place unless recycling schemes exist, and even then it may not be possible if recycled materials are contaminated. These two approaches can be used together guide decisions around plastic use.
The key considerations when thinking about the life cycle impacts of end-of-life options for plastic in Aotearoa New Zealand are:
- The waste hierarchy is generally appropriate to guide end-of-life management of plastic products but this may not be the case for specific applications or contexts.
- LCAs should be used to investigate situations where there may be greater environmental impacts associated with reducing, reusing or recycling products at end-of-life.
- Decisions about end-of-life management for plastics should be based on priority environmental impacts – right now this might mean reducing plastic pollution and mitigating climate change.
- Landfills are not a long-term solution for plastic waste but modern landfills may be an appropriate interim measure while we transition to zero plastic waste (read the Case Study)
Summary and recommendation
LCA is a tool that should be used alongside information from others in the toolbox to inform decisions. For example, one of the biggest issues related to plastic – the negative impact on ecosystems when leaked into the environment – isn’t currently addressed in LCA. While there are unacceptable leakages in the system, as evidenced by the worldwide build-up of plastic debris and widespread presence of microplastics, these impacts must also be considered during product choice. These are not simple to incorporate into LCAs as there is as yet no agreed value for environmental damage, but work is underway to standardise this. Currently we simply don’t know (beyond anecdotally) how big the impact is of plastic in the environment – but the evidence is growing.
The evidence for life cycle environmental impacts of plastic need to be considered alongside the social, technical, health and economic aspects of material choice. As yet, these are also not factored into LCA studies and need to be part of the decision-making process. In the context of using LCAs as a tool to support policy decisions, it is important to perform sensitivity analyses with different scenarios to understand potential changes in outcome.
The evidence for life cycle environmental impacts of plastic need to be considered alongside social, technical, health and economic aspects of material choice
It is also important to scrutinise the LCAs used to inform decisions. How accurate and relevant the LCA findings are depends on the quality of the input data and the context of the study. For example, it may not be appropriate to base decisions for Aotearoa New Zealand’s use and disposal of plastics on LCA studies completed in a European context when the logistics of transport and end-of-life disposal options are quite different. Caveats should be noted when drawing on studies undertaken for a different context. It may be possible to adapt overseas LCA data in order to partially address the Aotearoa New Zealand context – however, in general more robust results will be obtained from developing a local dataset because our transport, infrastructure, electricity generation, and imports and exports are all quite unique. Quality, localised data are crucial to ensuring the LCA findings provide robust evidence to support decision making to reduce environmental impacts. There are big data gaps and a lack of publicly available LCA studies related to plastics in Aotearoa New Zealand. The need for high-quality local input data for LCA studies to inform rethinking plastics highlights the need for rigorous local pilot data gathering. We need to model the Aotearoa New Zealand situation and support businesses and policymakers to make decisions based on these studies, with guidance from people with expertise in LCA.
Life cycle assessments should be used as part of decision-making processes around plastic policy, product redesign, and waste management systems. We need to be guided by evidence that is relevant for our situation in Aotearoa New Zealand. The environmental impacts associated with a product very much depend on the local context – such as the logistics of transport or whether recycling is available – so, in evaluating the evidence from studies in other countries, we should consider whether the context is similar to Aotearoa New Zealand or whether local studies are necessary. This is addressed within recommendation 3.
Key considerations for implementing this recommendation:
- A centralised database of NZ LCA datasets that is accessible to everyone could facilitate LCA studies in Aotearoa New Zealand. The Building Research Association of New Zealand (BRANZ) has published datasheets on transportation distances for construction materials, wastage rates on construction sites, etc. that can be used in New Zealand LCA studies, which could be used as a model for plastics and packaging.
- Linking with international initiatives on standardised dataset provision will enhance usefulness, credibility and uptake of NZ datasets e.g. forming a node linked to the United Nations’ Global LCA Data Access network (GLAD)
- Simplified decision-support tools based on LCAs may be appropriate for some sectors. For example, LCAQuick is designed for architects, designers, and structural engineers to use early in the building design process.
- The Australasian EPD Programme has experience in supporting and promoting NZ LCA studies, and can provide insights and expertise.
Impacts of plastic leaked into our environment
Plastic debris has been identified throughout the environment – from air to land to remote uninhabited islands to the deepest trench in the ocean. Plastic pollution is pervasive. The majority of studies measuring plastic pollution in the environment have been undertaken overseas with several estimating the amount of plastic pollution on a global scale. A study by Jambeck et al. in 2015 calculated that of the 275 million tonnes of plastic waste generated in 192 coastal countries in 2010, 4.8-12.7 million tonnes entered the ocean. It is estimated that 80% of marine plastic debris comes from land and only 20% from ocean-based sources, with commercial fisheries being a large contributor. A study of how land-based plastic debris reaches the ocean through rivers estimated that 88–95% of the global load of ocean plastics is transported through 10 large rivers with population-rich catchments.
The highest reported density of plastic debris anywhere in the world was on Henderson Island, a remote island in the South Pacific, with up to 670 items/m2 on the surface of beaches in 2017. More recently, it was reported that around 25% of the 400 million anthropogenic debris items on the remote Cocos (Keeling) Islands 2100 km northwest of Australia were disposable plastics. Plastic waste was also identified on the seafloor of the Pacific Ocean’s Mariana Trench – the deepest place in the ocean.
Current estimates give us an idea of the scale of plastic waste that has already been littered into our environment, but beyond high-level estimates we don’t know the amounts and types of plastic in the ocean. These estimates also highlight that the issue of plastic pollution reaches much further than what we can see – of the 86 million tonnes thought to have ended up in the sea, it is estimated that only around 0.5% is floating at the surface, with the rest below the surface or at the bottom of the ocean. Studies estimating the volume of plastic debris on the ocean surface have discrepant findings due to different methods. One study estimated between 7,000–35,000 tonnes on the sea surface, while another estimated 93,000–236,000 tonnes.
Of the 86 million tonnes thought to have ended up in the sea, it is estimated that only around 0.5% is floating at the surface with the rest below the surface or at the bottom of the ocean
The field of research identifying the impacts of plastic in the environment is relatively new and there have been many efforts to review the current evidence-base. The main focus of this workstream is to highlight evidence that is particularly relevant to support policy decisions that aim to reduce or prevent the impacts associated with plastic pollution for Aotearoa New Zealand (a summary of the evidence quantifying the presence of micro and macro plastic debris in Aotearoa New Zealand can be found here).
We cover the following issues with a brief summary of available evidence, what it means for our local context, and possible actions to be taken:
- Plastic causes physical harm to marine life and other species
- Additional risks come from chemicals added to plastic
- We don’t fully understand the impacts caused by microplastics
- We know less about the impact of even smaller plastic particles (nanoplastics)
- Plastic pollution poses a biosecurity risk
- Plastic may contribute to antimicrobial resistance
- Plastic may impact human health and wellbeing.
Plastic causes physical harm to marine life and other species
There is extensive evidence that plastic pollution harms marine life and seabirds by causing injury or death through entanglement or ingestion of plastic debris. It is estimated that plastic waste kills up to 1 million seabirds, 100,000 sea mammals and marine turtles, and countless fish each year. There are documented encounters of 800 species with marine litter, the majority being plastic, which include every species of turtle, 66% of marine mammal species and 50% of seabird species. Physical harm can also be caused by plastic-related habitat change. These impacts are described in detail in the Royal Society Te Apārangi report on plastics in the environment and Marine Litter Vital Graphics by the UNEP, which summarises the evidence of the scale, ecological impacts, economic and social costs, human health threat and possible policy responses.
It is estimated that plastic waste kills up to 1 million seabirds, 100,000 sea mammals and marine turtles, and countless fish each year
The biggest concerns are that:
- The effects are widespread. Ingestion of plastic affects the whole food chain and recent evidence suggests that several species show a preference for ingesting plastics over their natural food source.
- It negatively affects biodiversity. Plastic ocean debris is contributing to a decline in marine biodiversity.
- We don’t know the extent of the impacts. There are significant knowledge gaps and new ways that plastic physically impacts the environment are still being discovered. For example, researchers identified a new type of plastic pollution that is encrusted onto tidal rocky shores – now known as plasticrust, which may be a new way for plastic to enter the marine food web. A new type of marine litter resulting from plastic that has been burned, which looks like rocks on the beach, has also been identified.
- The problem will compound. Plastic is accumulating in the environment because it takes such a long time to break down, so the environmental risks will continue to increase as plastic pollution becomes more pervasive, unless serious efforts are made to eliminate and remediate plastic pollution.
What this means for Aotearoa New Zealand
Despite our remoteness and established waste management systems, Aotearoa New Zealand’s local wildlife is not immune to physical harm from plastic pollution. There is evidence that plastic harms our local and native species, some of which are already endangered. We don’t know the extent of every species that is impacted by plastics in Aotearoa New Zealand, but a handful of studies have demonstrated that ingestion and entanglement have caused harm to endangered green turtles, seabirds, fish, and fur seals. In fact, the rates of entanglement for the fur seals in Kaikoura were among the highest reported in the world. Further research is underway to quantify plastic ingestion in local wildlife (see Appendix 6).
The rates of entanglement for the fur seals in Kaikoura were among the highest reported in the world
Seabirds are particularly important to consider – we are home to one-third of all species of seabird and the breeding ground for the highest number of seabird species worldwide. Because of this, plastic debris in our seas poses a higher risk to seabird populations and efforts to protect these species and their ecosystems by preventing plastic in the environment are crucial. As part of practising kaitiakitanga, it is important that further research analyses the risks to native and taonga species and how to protect them.
Actions that could reduce physical harm to marine life
- Ban or redesign problematic products that are known to cause harm because of being mistaken for food (e.g. clear plastic bags resemble jellyfish and are ingested by turtles, and bottle lids and smaller fragments are mistaken by seabirds as prey items) – guided by data and innovations
- Determine local sources of plastic pollution and direct efforts to stop at source
- Coordinate efforts with international programmes to reduce plastic leaking into the environment
- Undertake research to address knowledge gaps not yet being addressed in local studies.
Additional risks come from chemicals added to plastic
One of the ways plastic pollution can impact the environment is through leaching of chemical additives – a considerable number of which are toxic – that are included in the polymer mix to give the plastic specific properties. Through this leaching process, plastic contributes to the exposure of organisms to hazardous chemicals. The associated risks of these chemicals entering the environment are directly related to plastic pollution and should be considered when rethinking plastics.
Some of the common chemical additives are ‘endocrine disrupting chemicals’ (EDCs), meaning they disrupt hormonal processes. Other common chemicals are ‘persistent organic pollutants’ (POPs) that are resistant to environmental degradation, so the concentrations will accumulate in the environment. The risks of toxic chemicals associated with plastics are discussed in greater detail in the Royal Society Te Apārangi report on plastics in the environment.
The biggest concerns are that:
- These chemicals can disrupt biological processes. Most plastic additives are lipophilic, meaning that if plastic is ingested the chemicals can easily move into the organism’s membranes and impact biochemical processes. There is early evidence that chemicals from plastic may contribute to population decline of a range of species by causing reduced fertility, fitness, mobility and immunity, increased risk of carcinogenesis, and changes to blood chemistry, hormone levels and gene expression.
- The concentration of chemicals – and any associated toxicity – can increase up the food chain. Chemicals can accumulate (i.e. concentrate) in tissues which are then ingested by predators (referred to as bio-magnification). Even a small amount ingested at the lowest level of the food chain (e.g. in zooplankton) may reach biologically-relevant levels as it moves up the food chain, leading to knock-on effects that could impact whole ecosystems. When chemical contaminants are attached to plastic it can inhibit the contaminant from degrading, further increasing concentrations of these chemicals that can potentially enter the food chain.
- Organisms are likely to be exposed to higher levels than what we currently measure. The high surface-area-to-volume ratio of microplastics leads to a faster rate of leaching of additives in the plastic and also a faster rate of adsorbing (and concentrating) other contaminants (including bacteria) that are already in the environment. After being swallowed these can desorb from the plastic particles in the gut leading to high rates of exposure. Most reported levels of chemical contaminants are from environmental monitoring and do not account for the increased rates of exposure in the gut due to these faster rates of adsorption and desorption.
- Removing chemical additives from plastic won’t fully resolve the issue. Even if all plastics didn’t have any chemical additives included in the mix, there remains the issue of other chemical contaminants (or bacteria) that are already in the environment adsorbing onto the plastic.
- Recycled plastic and biodegradable plastic also contribute to the problem. Recycled plastic may inadvertently carry chemical additives from the source plastic. Unless specifically designed to be marine-biodegradable, biodegradable plastics are basically non-degradable in seawater and may also pose a toxicity risk.
What this means for Aotearoa New Zealand
We know that there is plastic pollution in our local environment and that this may bring with it associated toxic effects, but current evidence for levels of chemicals associated with plastic pollution around Aotearoa New Zealand is lacking. One study tested for POPs associated with plastic pellets/nurdles around Australia and Aotearoa New Zealand’s North Island, as part of a global monitoring programme called International Pellet Watch. The study identified high concentrations in Auckland and Australia’s large cities, and very low concentrations at the tip of the North Island. In the latest survey of groundwater, ESR detected BPA at very low concentrations, which could be contributed to by plastic among other sources.
To better understand the risks to Aotearoa New Zealand and guide decision making, studies need to determine the levels of various chemical contaminants across the country, and the associated exposures for organisms through the food chain, including humans.
Actions needed to reduce risk related to plastic additives
A review of the toxic chemical components of marine litter plastics and microplastics to inform the working groups for the Stockholm and Basel Conventions concluded that there is a need for urgent preventative measures to reduce ongoing risk from chemicals added to plastic.
Priority measures include:
- Preventing plastic leaking into the environment
- Identifying the additives or products that pose the highest risk of toxicity and using lower risk replacements
- Drawing on international studies and evidence of the impacts of chemicals associated with plastic
- Undertaking research to address knowledge gaps not yet being addressed in local studies, including initiating studies of plastic-associated POPs and EDCs at various locations throughout Aotearoa New Zealand.
We don’t fully understand the impacts caused by microplastics
Microplastics are small pieces of plastic less than 5 mm in length, either made that size or degraded from larger plastics. The field of research into the impacts caused by microplastics is in its relative infancy and the evidence is not clear cut. There is a mounting body of evidence that microplastics are present in a very wide range of ecosystems and ingested by a range of organisms, but the physiological implications of this are less certain.
The European Commission’s Group of Chief Scientific Advisors articulated this based on the evidence review on the environmental and health risks of microplastic pollution provided by SAPEA (Science Advice for Policy by European Academies):
“SAPEA (2019) shows that the available scientific knowledge on microplastic pollution and its impacts is a mix of consensus, contested knowledge, informed extrapolation, speculation and many unknowns. This reflects both the immaturity of the field and its intrinsic complexity.”
The biggest concerns are that:
- All ecosystems are at risk. As well as being pervasive in the marine environment, microplastics are present in freshwater, soil and air, and therefore any identified impacts are likely to be widespread. Beyond the marine ecosystem, the limited but growing body of evidence indicates that microplastics may cause negative impacts for soil and freshwater as well.
- Species of all sizes are affected. This occurs through ingesting plastics or via the food chain. A semi-systematic literature review found that marine plastic has a global impact on all ecological subjects reviewed, which included bacteria, algae, zooplankton, invertebrates, fish, turtles, birds and mammals. Most of the impacts of marine plastic pollution were considered irreversible.
- We don’t know the extent to which plants that we eat are taking up microplastics. There is early evidence that under lab conditions, microplastics accumulate on pores in seed capsules and cause short-term transient effects including delayed germination and root growth, and are taken up by lettuce. A study analysing whether plants took up microplastics when grown in commercial compost that had been used for biodegradable plastics found some evidence for around half of samples tested. These findings were published in a Masters’ thesis, but not yet in the peer-reviewed literature. Further research is required to replicate all of these findings.
- Microplastics may be spread through the environment via wastewater. A proportion of microplastics are removed in wastewater treatment plants – the extent of removal depends on the level of treatment and type of infrastructure. Those that are retained in the solid fraction could contaminate terrestrial ecosystems if applied as fertiliser or for land rehabilitation, and some remain in the final effluent contaminating aquatic ecosystems.
- Leachate from poor quality landfill may contain microplastics that leak into the environment. There is evidence of leachate from landfill containing microplastics in China and Nordic Countries, but this hasn’t been studied in Aotearoa New Zealand.
- We don’t understand the risks from current levels in our environment. Most lab studies use far higher concentrations of plastic that do not reflect those in the natural environment – on the flipside, we may not know the true environmental concentrations due to limit detection of available methods and these high levels may be reached in the future as an increasing amount of plastic accumulates and degrades in the environment.
What this means for Aotearoa New Zealand
Overall, we don’t know the extent to which microplastics will impact Aotearoa New Zealand because we don’t have a clear understanding of the scale of microplastic pollution at various locations and for different ecosystems, and the impacts of microplastics are still being determined. This was highlighted in a recent review of microplastics risk for Environment Southland by researchers from the Cawthron Institute. This review concluded that ‘the risks microplastics pose to ecosystem and human health are not fully characterised and many research and knowledge gaps remain’. Implementing systems to reduce microplastics entering the environment from the known biggest sources can minimise future risk.
Two studies have detected microplastics in the marine environment, one in Christchurch and the other in Auckland. For wastewater, early results of a study quantifying microplastics in influent and effluent (but not biosolids) at Christchurch’s main wastewater plants shows that microplastics are present and that the different levels of treatment used at each plant removes different amounts of microplastics. These studies are a great starting point but need to be replicated at different sites throughout the country as data cannot necessarily be extrapolated to other regions for a number of reasons including differences in population size, different treatment plant type, and clothing needs for different climates.
Local studies are underway to address some microplastics knowledge gaps for Aotearoa New Zealand through the ESR-led MBIE Endeavour Aotearoa Impacts and Mitigation of Microplastics project, including:
- Microplastics monitoring and education (read the Case Study)
- A better understanding of the quantity of microplastics going into wastewater treatment plants (influent) and coming out (effluent), and what’s left (biosolids) – considering the effects fragmentation to a size below detection level
- Which stages microplastics leave the liquid phase and/or fragment during the treatment process
- The fate of microplastics used for irrigation/biosolids application and whether they make it to groundwater systems
- The interaction between microplastics and chemical contaminants
- The interaction between microplastics and potential pathogens, soil health and groundwater ecosystem health.
Actions needed to reduce potential risks associated with microplastics
Preliminary local data, global studies highlighting the pervasiveness of microplastics, and the growing body of evidence demonstrating negative impacts on ecosystems, warrant the precautionary principle being applied for microplastics. Preventative measures should be implemented to stop (or remediate) leakage of microplastics into the environment, in concert with focused research to quantify and understand the impact of microplastics in our local setting, particularly on native flora and fauna and taonga species.
Priority actions include:
- Implementing preventative measures or remediation techniques
- Building on existing efforts to quantify microplastics in Aotearoa New Zealand across a range of locations and different ecosystems (including marine environment, landfill leachate, wastewater, soil, air) and implementing ongoing monitoring. This also requires developing a more efficient method to process samples, which is currently a bottleneck
- Monitoring international research and undertaking complementary and collaborative research to address knowledge gaps not yet being addressed in local studies.
We know less about the impact of even smaller plastic particles (nanoplastics)
Less is known about the impacts of smaller plastic fragments (nanoplastics) on organisms, including humans. Research into nanoplastics has only begun recently.  Nanoplastics are naturally formed from the degradation from the larger microplastics that are abundant in the environment, as well as being produced in manufacturing of other products. Initial studies imply that nanoplastic is very abundant where microplastic is abundant (up to a billion particles of 100 nm size can be formed from the breakdown of one 5 mm microbead), and can have very long residence times in aquatic environments.
However, there are very few direct measures of the amounts of nanoplastics in the environment, and none currently in Aotearoa New Zealand. It is a particular challenge to measure the amounts, sizes and shapes of these particles because of their small size and composition, and methodological development is required to enable this.
Nanoplastics, in common with other nanoparticles, are of particular concern because they are much more biologically available – able to cross natural biological defence barriers.  This gives them longer retention time in plants and animals, and also increases the probability of transfer of surface contaminants into organisms.  They are easily inhaled and able to penetrate deeply into the human lung. These particles are very challenging to remediate, as they are smaller than the normal filter sizes used for particle clearing, and require ultrafiltration.
The biggest concerns are that:
- It is hard to measure nanoplastics. Measuring the levels in the environment is hindered by issues with isolation, identification and contamination. With current methodological limitations it is difficult to assess the quantity and impacts of particles of this size.
- It is hard to treat nanoplastics. Nanoplastics are smaller than normal filters and require ultrafiltration to remove from air or water.
- The smaller size may mean fragments move into organs more easily. Early evidence suggests that the smaller size may help these fragments pass through membranes and be transported into organs. Inhalation is a greater issue than for larger particles.
- Nanoplastics may have a longer retention time than microplastics. Once ingested, nanoplastics may cross cell membranes and enter the bloodstream and organs, resulting in a longer retention time in the body than larger microplastics.
- The principles of trophic transfer apply. Smaller particles can be ingested and accumulate up the food chain in the same way as microplastics. They may also be able to be taken up through other routes such as across gills of fish or through endocytosis by plants.
We can’t yet assess the risks associated with nanoplastics. This needs to be a focus of future research
What this means for Aotearoa New Zealand
Like microplastics, there is the potential for negative impacts associated with these plastic particles to affect our native flora and fauna, taonga species and human health. Because the field of research is new, there is little local evidence. However, the mobility of nanoplastics into tissues provides the potential that they may transfer to the edible tissues of organisms.
Actions needed to address potential risks of nanoplastics
Even though the body of evidence is far smaller, the precautionary principle should apply to smaller plastic particles as well. Methodological improvements are a priority to ensure that nanoplastics can be quantified in the environmental setting, and once this is achieved ongoing microplastic monitoring efforts should incorporate nanoplastics. Source prevention and remediation efforts should also factor in the far smaller fragment size of nanoplastics.
Plastic pollution poses a biosecurity risk
If lost in the ocean, plastic can travel a huge distance over a long amount of time. This was illustrated by the journeys of more than 28,000 rubber ducks lost at sea in a shipping container en route from China to Seattle in 1992 – the ducks washed up across beaches over a decade later far away from where they were lost.
The buoyancy and strength of plastic make it an ideal raft to transport species over large distances, over long periods of time. These features of plastic mean it can facilitate travel into areas species previously wouldn’t have been able to get to, through water, soil or air. There is evidence of invasive species travelling via larger plastic objects and microbes travelling via microplastics.
The biggest concerns are:
- Plastic pollution may help spread pathogens and invasive species. Plastic debris provides a unique environment that allows complex communities, including pathogens, to survive and travel where they may not normally.
- Ingestion of plastics colonised with microbes may spread pathogens further. Ingestion of plastics by marine animals can also facilitate transmission of pathogens to other animals in the same species through close contact, and bridge the gap between ecosystems.
- New or invasive microbial species have the potential to alter whole ecosystems. Introduction of new microbes via plastics may cause significant changes in existing microbial communities and could potentially alter ecosystem function and processes such as nutrient cycling.
- Rafting of organisms poses a threat to global biodiversity. The incidence of anthropogenic debris has more than doubled the rafting opportunities for organisms and therefore poses a significant threat to global biodiversity.
What this means for Aotearoa New Zealand
Exotic plant and animal pests that hitchhike on plastic in the sea could threaten Aotearoa New Zealand’s biosecurity. A study of 27 beaches along the Coromandel Peninsula found that plastic debris poses a high risk of transfer for both native species and non-indigenous marine species, creating a biosecurity risk. The main culprit for carrying bio-fouling taxa, particularly biosecurity pests, was rope debris used in fisheries and aquaculture. Further studies are needed, but this early evidence suggests that better management of plastics used in marine environments could reduce biosecurity risks.
Actions needed to reduce biosecurity risk related to plastic
The ultimate action that will reduce the risks associated with plastic pollution is to minimise plastic litter. In conjunction with this, research needs to address knowledge gaps not yet being addressed in local studies (see Appendix 6), including studies to better understand what poses a threat to Aotearoa New Zealand biosecurity through plastics. The ESR-led MBIE Endeavour Aotearoa Impacts and Mitigation of Microplastics project is partly addressing this by looking at species that pose a biosecurity risk (invasive species or pathogens).
Plastics may contribute to antimicrobial resistance
The microbes that colonise microplastics may be human and animal pathogens. The influence of microplastics on microbiological health risks is a growing area of research. There is emerging evidence that the biofilm environment established by microbes on microplastics is one that can support the spread of antimicrobial resistance, if it also attracts antibiotics or other chemicals that select for resistance. Antimicrobial resistance is considered an imminent threat to Aotearoa New Zealand. Our understanding about the risks of microplastic-associated antimicrobial resistance is currently very limited and we don’t yet know the extent to which plastics may facilitate antimicrobial resistance and what downstream risks that poses for this global health issue. The potential for plastic pollution to contribute to this risk needs to be better understood through local research as well as monitoring findings from international research efforts.
Plastic may impact human health and wellbeing
A comprehensive report on the risks to human health caused by plastic, led by CIEL, provides a detailed overview of the health impacts associated with plastic particles and associated chemicals at every stage of its supply chain and life cycle.
In brief, the risks outlined include:
- Extraction and transport: Potential carcinogenic, neurotoxic and disruptive effects to the reproductive and immune systems from the chemicals used to produce the main feedstocks for plastic, putting industry workers at risk.
- Refining and manufacture: Potential carcinogenic and toxic effects from the chemicals used to transform fossil fuel into plastic resin and additives. Because these are airborne, industry workers and neighbouring communities are particularly at risk.
- Consumer use: Potential carcinogenic, developmental or endocrine disrupting impacts from exposure via ingestion or inhalation with plastics that have certain chemical additives or contaminants.
- Plastic waste management: Different processes may release various toxic substances to the air, water and soils to those working in the industry or living nearby. This depends on the waste management approach and the chemical contaminants on the plastic.
- Plastic in the environment: People may be exposed via microplastics in the environment or through the food chain. The risks from chemical contaminants increase as the plastic degrades.
The World Health Organization (WHO) examined the evidence related to the occurrence of microplastics in the water cycle, the potential health impacts from microplastic exposure, and the removal of microplastics during wastewater and drinking-water treatment.
The WHO concluded:
- Microplastics are ubiquitous in the environment and have been detected in a broad range of concentrations in marine water, wastewater, fresh water, food, air and drinking-water (bottled and tap). The data on the occurrence of microplastics in drinking-water are limited at present, with few fully reliable studies using different methods and tools to sample and analyse microplastic particles.
- The potential hazards associated with microplastics come in three forms: physical particles, chemicals and microbial pathogens as part of biofilms. Based on the limited evidence available, chemicals and biofilms associated with microplastics in drinking-water pose a low concern for human health. Although there is insufficient information to draw firm conclusions on the toxicity related to the physical hazard of plastic particles, particularly for the nano size particles.
- Limited evidence suggests that key sources of microplastic pollution in fresh water sources are terrestrial run-off and wastewater effluent. However, optimised wastewater (and drinking-water) treatment can effectively remove most microplastics from the effluent. For the significant proportion of the population that is not covered by adequate sewage treatment, microbial pathogens and other chemicals will currently be a greater human health concern than microplastics.
The biggest concerns about plastics and human health are:
- We don’t know how much plastic humans ingest or inhale, beyond a few estimates and comparisons. Precise data to assess the exact exposure of humans to micro- and nanoplastics via diet cannot be produced until standardised methods and definitions are available. A recent high profile study by researchers at the University of Newcastle estimated that an average person could be ingesting approximately 5 grams of plastic every week – the equivalent of one credit card. Sources of ingestion identified in the study included drinking water, shellfish, beer and salt. This study did not include data from Aotearoa New Zealand. Another recent study found that certain fancy teabags release billions of microparticles.
- We don’t understand the short- and long-term risks of exposure. Uncertainties and knowledge gaps mean that we aren’t able to fully evaluate the human health impacts of plastic. The evidence is difficult to assess and findings are contested. The Netherlands Organisation for Health Research and Development has funded 15 short-term projects as part of a Microplastics and Health programme. Interim results were shared at a summit in October 2019, but final results are not due until mid-2020 and funding has been granted to extend these projects.
- The consequences to human health from plastics transferred through the food chain are unclear. Seafood has been identified as a potential route of microplastics and associated chemical pollutants into the human diet, with a growing body of literature demonstrating the presence of nano- and microplastics in commonly eaten marine species, such as mussels, oysters, fish, sea cucumbers and lobsters. Further investigation is required.
What this means for Aotearoa New Zealand
Plastic is imported to Aotearoa New Zealand as resin or manufactured plastic materials, so our local population is not affected by the potential risks outlined above for the extraction, transport, refining and synthesis of the constituent compounds as well as the manufacture of the finished resins. Potential risks of those stages of the plastics life cycle should be factored in with any new approaches to onshore production and manufacture of plastics, including bio-plastics.
Our understanding of how much plastic and the different types of plastic people in Aotearoa New Zealand are exposed to through consumer use, waste management and environmental exposure is very limited. This information is a prerequisite to being able to identify risks to human health. With current evidence we cannot determine the risk that plastic poses to the health for people in Aotearoa New Zealand.
A few studies have quantified the levels of plastic in local food sources:
- A study quantified microplastics in table salt, but limited results did not allow for determination of the potential dietary intake
- Research from the University of Auckland’s Institute of Marine Science identified that 33 out of 34 commercial fish species had evidence of ingested plastic across four locations in the South Pacific, including Auckland. The maximum ingestion rate was recorded in a New Zealand species, Kyphosidae or Parore, as well as in yellowfin tuna from Rapa Nui. Out of the eight most common species specific to Aotearoa New Zealand, only one did not ingest plastics. Note that plastics in the gut of fish would not be ingested by humans, but plastic or chemical contaminants in tissues could be.
More studies to quantify the levels of plastic in local food sources are required, particularly for shellfish because people eat the whole animal. A study is underway at the University of Auckland investigating microplastics in Aotearoa New Zealand food and beverages.
Though data are limited, we can estimate exposure through food sources using existing evidence as a starting point. For example, the yearly consumption of different mollusc species in Aotearoa New Zealand is around 440 g per capita per year. Using the average microplastic load detected in mollusc species, the dietary exposure to microplastic through mollusc consumption can be around 924 and 4620 microplastic fragments per capita per year. However, the estimate for microplastic loads in shellfish in Aotearoa New Zealand is highly uncertain as there are currently limited data available for the levels of microplastics in shellfish grown in Aotearoa New Zealand waters, highlighting the need for greater assessment of the current level of contamination within food. This was partly addressed in a local study that quantified microplastics in green-lipped mussels from around Aotearoa New Zealand, which found zero to 1.5 particles in mussels at six out of nine locations tested. This initial study noted that it is likely that the methods used underestimated the levels. Ingestion of plastics through seafood and seabirds may be of particular concern for tangata whenua.
We can also look beyond the potential health risks associated with ingestion through marine food sources and determine how else people are exposed to microplastics in Aotearoa New Zealand and what health risks may be associated with this exposure. Recent evidence suggests that groundwater has the potential to become contaminated by the land disposal of wastewater effluent and biosolids, and horticultural plastics. This is of particular concern for Aotearoa New Zealand as we rely heavily on groundwater as a source of drinking water. Some knowledge gaps for this will be addressed by a new study by the Ministry for Primary Industries, New Zealand Food Safety. This project will analyse the dietary exposure of microplastics, absorption rates of plastics and their contaminants through the human gut, impact of cooking/food prep on the microplastics and their contaminants and influence on absorption/risk.
There is also evidence that plastic litter on beaches may cause injury. A local study determined that anthropogenic beach litter, including plastic, poses a common and pervasive exposure hazard to all ages, with a specific risk to young children. Plastic litter may further impact wellbeing through changes to food provisions, livelihoods and income, especially in coastal communities. Cultures that are closely linked to the ocean and environment and particularly vulnerable to these changes. For Māori, this may be expressed through the mauri of a resource being negatively impacted. Existing environmental assessment tools and frameworks that observe the mauri of a specific environment may be helpful to track the impact of plastic on certain environments (outlined in Appendix 7).
Actions needed to reduce health risk to humans
Despite significant knowledge gaps, the available evidence around the pervasiveness of plastics in the environment suggests a precautionary approach is appropriate. This could include monitoring levels of plastics in food and drinks (following international best practice e.g. the European project ‘ECsafeSEAFOOD’) and filtering small particles from water.
Ways to prevent and reduce the impacts of plastic pollution
Preventing and reducing the impacts of plastic pollution requires a multipronged approach that includes reducing the use of plastics overall, prioritising the redesign of products that may end up in the environment at end-of-life so that they have the least environmental impact if this is their fate, preventing leakage at source, remediating existing pollution, and sector-specific approaches to mitigate economic impacts. Effective, systemic and enduring mitigation of this environmental harm requires measurement and monitoring tools not yet developed in Aotearoa New Zealand, and only unevenly applied in other countries.
Focus on prevention at source
Preventing leakage of any litter into the environment to avoid the impacts on wildlife and ecosystems is challenging with today’s infrastructure and consumption habits, and we know that a considerable amount of plastic that is produced worldwide ends up polluting our environment. The Ocean Conservancy published a report ‘Stemming the Tide: Land-based strategies for a plastic-free ocean’ which details a series of solutions that could help to prevent leakage of plastic from land into the oceans – specifically focused on viable opportunities that exist today.
Knowing how and where plastic enters the environment is fundamental to preventing (or reducing) any associated impacts. There have been global efforts to broadly quantify the sources of plastic pollution – such as the estimate that 80% of marine-based plastic comes from land – and the main mechanisms are generally well understood. The ultimate goal should be to prevent all leakage of plastic into the environment. In order to do this, we need a complete understanding of the mechanisms through which plastic enters the environment in Aotearoa New Zealand. We currently don’t know the sources, routes, how much and which types of plastic enter the environment in Aotearoa New Zealand. That information is critical to prioritise efforts to reduce environmental leakage at source.
Here we present several case studies that demonstrate failure in Aotearoa New Zealand’s systems that lead to plastics entering the environment through landfills (read the Case Study), tyres (read the Case Study) and clothing (read the Case Study). These case studies highlight where we should start to prevent environmental leakage of plastic, while better data are captured to inform priorities and solutions to address the whole system of plastic pollution.
Remediate existing plastic pollution
Stopping plastic pollution at source is critical to reduce the impact of plastic on the environment, but even if we stopped any further plastic from entering the environment today, there will still be an enormous volume of plastic in our oceans. Larger, visible plastic items will continue to degrade into smaller plastic particles that become less visible and less easy to remove. Efforts to remove plastic debris are warranted and there are numerous efforts around the world to remove larger bits of plastic debris from the land and oceans. For example, the US NOAA marine debris program supports many different removal projects, mostly through funding locally driven community initiatives. In Aotearoa New Zealand, several NGO groups are dedicated to removing plastic debris from the ocean or coastlines, including Sea Cleaners and Sustainable Coastlines, while others retrieve litter before it makes its way into our waterways.
Larger, visible plastic items will continue to degrade into smaller plastic particles that become less visible and less easy to remove
Though removing some marine plastic is possible, it is time intensive, expensive and inefficient. More efficient and cost-effective remediation techniques for larger ocean plastics will be crucial to reduce the impact of plastic in the environment. Recent reports indicate that an ocean clean-up device was able to successfully retrieve plastic from an ocean gyre for the first time during a trial, with plans to now scale-up and improve the device.
For microplastics or smaller particles, there are no remediation methods currently available that could quickly, efficiently and safely remove these from the environment. This area of research should be watched closely to see what opportunities could be scaled-up. Before scaling, it is important that rigorous testing is done to prevent unintended consequences. For example, we need to be sure that the remediation technique doesn’t harm small organisms in the environment at the same time. Some initial studies have shown potential on a small scale using methods such as:
- Bioremediation (using microorganisms) to remove microplastics
- Decomposing and mineralising microplastics using nanosprings
- Removing microplastics from water using liquids known as ferrofluids.
Already some products have been developed to reduce the amount of litter that enters the oceans and waterways, by intercepting litter from land before it enters stormwater drains, such as the LittaTrap. Continued research into techniques that safely and effectively remove or intercept plastic from the environment, including small particles, is necessary.
Mitigate potential economic impacts
Most analyses to quantify the economic impacts of plastic pollution have focused on ocean plastics. The currently available evidence for the ecological, social and economic impacts of marine plastic was synthesised in a recent review. In that study, the global estimate of the economic impact of marine plastic was around $2.5 trillion each year. A detailed analysis of the local economic implications of plastic pollution are outside of the scope of this report. However, this is an important area that requires further research and consideration. The presence of plastic in the marine environment has a significant impact on the economy of a country in several different ways. The key ways are through changes to:
- Tourism: Larger plastics and plastic fragments, which are easily seen with the naked eye, can affect the aesthetics of the coastal zone. As plastics are a very clear visual indicator of human pollution their presence may directly impact a country’s tourism industry by affecting the image of having clean, pristine environments. This can therefore have an impact on the country’s reputation and consequently the number of visitors they will get. It will also affect the perceived value of a place and therefore the monetary value as a destination.
- Fisheries: Microplastics may have a multifaceted impact on fisheries-based economies in both the short and long term. Their direct impact on animal health and reproduction may affect fisheries stocks and/or the health of the ecosystem on which they rely. For example, larval fish may starve due to preferential feeding on microbeads, resulting in a crash in the population, and a knock-on effect on higher trophic levels. Pathogens may be transported to areas that have previously been geographically isolated, but are now accessible due to the long-range movement of plastic fragments.
- Export industry: Fisheries exports may be hindered by the contamination of seafood. Although more research is required to determine the level of risk to human health through the consumption of plastic-contaminated seafood, the evidence that already exists gives cause for concern. Should a health risk be demonstrated, legislation for microplastics and nanoplastics as contaminants in food, similar to those currently in place for other forms of contamination such as microbes and chemicals, may be implemented by importing countries. However, the lack of evidence does not necessarily negate the potential negative impact on the seafood industry that the presence of plastic may have. The public’s perception of the purity of the seafood may have a deleterious effect on its own.
What this means for Aotearoa New Zealand
The economic risks of plastic pollution may be of greatest concern to countries who market their seafood as ‘pure’ and grown in the wilderness away from the impacts of human activity and for those who rely heavily upon their seafood export industry. This makes Aotearoa New Zealand particularly vulnerable to the economic implications associated with plastic in the marine environment. Our NZ$1.48 billion per year wild-capture fishery (estimate for 2018) is at risk from microplastic pollution. These impacts are likely to become more pronounced as plastic pollution accumulates and degrades into smaller pieces that will be more accessible to species lower down the food chain. Some see this as a ‘ticking time bomb’ for our aquaculture and fisheries industries.
Our tourism and agricultural industries could also be at risk. A study by the Ministry for Primary Industries determined that with Aotearoa New Zealand’s worldwide reputation for high quality wine, any changes due to microplastics in the soil resulting from the accumulation of millions of discarded netting clips over years and decades could affect this NZ$1.61 billion export industry. Further work currently underway by the Ministry for Primary Industries aims to better assess the potential trade/socio-economic impacts of plastic pollution for our country. The global increase in plastic pollution also brings with it opportunities. It is likely that there will be a market for food and seafood that is ‘plastic’ free.
The knowledge gaps around scale and impact of plastic pollution in our local context make it difficult to fully understand the potential economic implications on Aotearoa New Zealand. Economic analyses should be undertaken to model the impacts of plastic pollution on different sectors, including aquaculture, fisheries, agriculture/horticulture, exports and tourism.
There are significant knowledge gaps around the impacts of plastic on the environment, which can be broadly grouped as:
- The sources, quantities, routes and fate of macro-, micro- and nanoplastics in Aotearoa New Zealand, specifically focused on marine, freshwater and terrestrial environments, and wastewater
- The impacts and risks of plastic on biodiversity and ecosystems, particularly for taonga species
- The impacts on health, including quantities of microplastics in food and drink sources in Aotearoa New Zealand and whether mana whenua may particularly be exposed to an increased dietary loading compared to the general population through recreational and customary harvest of wild foods
- The characteristics and levels of chemical additives and contaminants associated with plastics in Aotearoa New Zealand and their impacts, including the degree of transfer and accumulation between levels of the food chain
- The levels and types of plastics in all landfills (current and decommissioned) and the risk of leaks to the environment through natural disaster, particularly in relation to climate change (changes in rainfall levels, storm frequency and intensity, sea level etc.), and through leachate
- The downstream impacts on the economy.
Summary and recommendation
There are impacts on the environment throughout the whole life cycle of a plastic product, with particularly significant impacts if leaked into the environment. There is still a lot we don’t know about the environmental and health impacts related to plastic. Research is required to address these knowledge gaps. Efforts to understand the risk to our local communities and taonga are essential, alongside international collaborative efforts to study impacts and align to international best practice. Without changing how we use and dispose of plastic, the environmental consequences are expected to be stark. It is critical to act now to protect the environment by using plastic in a sustainable and responsible way. This is addressed through the series of recommendations within recommendation 6. Key considerations for implementing these recommendations:
- Mana whenua should be supported to be involved in environmental monitoring aspects of plastics.
- Ensure that research is connected to international research communities and prioritises filling local knowledge gaps.
- Ensure that measures to reduce environmental impacts of plastic align to international pacts, pledges and data collection framework, including:
- Draw on local ongoing efforts related to plastic in the environment, including
Plastic resource portal
At a glance summary
Two-page summary of the findings
40-page summary of the key messages
The long and detailed full report
All infographics developed for this report