Plastic seems so clean. It’s smooth, easy to wipe. The sauce bottle squeezes nearly everything out. The stretchy yoga pants dry fast. The plastic teething toy has such bright colours. The carpet resists stains. These diverse properties are thanks to the dizzying array of chemical additives that help make plastic clear, stretchy, rigid or whatever else we like about it.
But if plastic is a concoction of carbon-based polymers and synthetic chemicals, what happens to the chemicals? It turns out that many of them are released during the plastics’ life cycle – into food, cosmetics or the environment. Recently, the academic arm of the United Nations published a summary of bottled water surveys showing that all the tested bottles released chemical pollutants, microplastics or microbial contamination into the water they contained – even in countries with strong health standards such as the US and Germany.
Plastics are known to be an important source of people’s chemical exposure. At least 900 chemicals are “likely” associated with plastic packaging – mostly plasticisers, stabilisers, antioxidants, pigments and flame retardants. Thousands more are “possibly” associated, which reveals a lack of transparency. Many haven’t been thoroughly tested for health effects. Some are known to be hazardous.
There are ways out of this quandary, but they need a new approach. Chemicals are added when products are designed and manufactured, so fresh thinking is needed at these stages. It could be worth it, though, as the remedies could also address other byproducts of plastics, from pollution and waste to climate change.
Recycling myths
First, a myth to dispel: recycling is not the most important thing individuals can do to slow climate breakdown, despite a recent Ipsos market research survey showing 45% of New Zealanders believe it is. Driving less beats recycling by a country mile.
But recycling could reduce emissions if it meant less new plastic was produced. Emissions from making plastics each year exceed Brazil’s annual contribution to global greenhouse gas emissions. It’s almost always made of oil or gas, and it’s energy intensive.
“One oil refinery uses enough energy to power a whole city,” says Alec Foster, biopackaging and portfolio lead at forestry-focused crown research institute Scion. After oil is refined, the naphtha that separates out is “cracked” at petrochemical plants at 850ºC to turn it into plastic precursors that are then linked to make polymers. Chemicals are added to the polymers to create plastic.
Plastic production is predicted to almost treble by 2060 and petrochemicals – which include plastic – are becoming the largest driver of oil demand.
“Unfortunately, a lot of the oil companies are shifting their primary focus from petrol to polymers,” says Foster. Large plastic-making companies are often subsidiaries of oil and gas companies or national oil companies.
Myth No 2: does recycling plastic really mean less plastic is produced? PhD student Warren Fitzgerald from Te Herenga Waka – Victoria University of Wellington says only about 2% of recycled plastic is remade into the same product it was originally. “So recycling a milk bottle is not necessarily reducing the demand for a new milk bottle.”
He points out that mechanical recycling can be done only a handful of times, as the process progressively breaks down the plastic’s polymers.
His research shows that our guilt is appeased if we think the plastic will have a second life. “The modelling I’ve done shows that the act of recycling makes us feel good about ourselves, so we feel justified in buying more stuff. It causes a rebound effect and might even induce more plastic demand than it prevents, but it certainly doesn’t induce less.”
![ESR’s Olga Pantos: “We found thousands of [microplastics] to a kilo of sand.” Photo / Trefor Ward](https://www.nzherald.co.nz/resizer/v2/4UNGQYSVEBG2FLDCJTHK4VW2E4.jpg?auth=7561d98d0339c343129089c558b36fc9a289944c2b20c8b86a66bf0b5fe02a3b&width=16&height=11&quality=70&smart=true)
Waste ethics
There’s an order to the motto “reduce, reuse, recycle”, Fitzgerald says. But “instead of focusing on reduce, we build recycling plants and material recovery facilities that cost millions. Then we get infrastructure lock-in, and we’re encouraged to use these systems, and that way of doing things becomes entrenched. It makes it hard to move away to systems that let us reduce and reuse.”
Changing entrenched systems usually brings economic and social pushback. An example occurred in August during Parliament’s environment select committee hearing into a petition calling for a ban on plastic waste exports to developing countries. Although our plastic waste is tidily whisked away on rubbish day (see “Not sorted”, page 24), we send roughly half to poor countries for recycling. Lydia Chai, an Auckland-based lawyer from Malaysia who created the petition, tells of plastic waste being dumped or buried there or processed in plants that are close to homes. She says local residents suffer the consequences of their country having lower environmental standards and fewer resources to enforce any regulations. “It’s unethical to send our waste there.”
With logic that Chai called “odious”, Plastics NZ advised that a ban would threaten the viability of Southeast Asia’s recycling plants and that informal wastepickers need the current system to make a living.
The committee agreed it was “unethical for communities in Malaysia to bear the burden of New Zealand’s historic underinvestment in plastics reprocessing infrastructure” but stopped short of an export ban. It recommended we invest more in local recycling infrastructure and set a deadline to phase out unlicensed plastic waste exports to countries beyond Australia.
Circular economy
Recycling is a last resort within something governments are increasingly aiming for: a circular economy. Way less raw materials will be extracted, less will enter the economy, and those that do will remain in circulation. Plastics would be eliminated where possible by redesigning systems, products and materials. Essential items that cannot be replaced should be reused as much as possible before being safely and sustainably recycled.
But two circular economy principles make plastics tricky to accommodate: eliminating waste and pollution, and restoring the environment. The problem is plastics’ chemical load and their breakdown into microplastics.
Take food packaging. About a third of the world’s plastic is made for packaging, so recycling it into packaging seems logical.
But is it safe? Phil Bremer, a professor of food science at the University of Otago, co-led a study by the New Zealand Food Safety Science & Research Centre into just this. “Recycled plastic tends to contain more non-intentionally added and intentionally added substances than virgin plastic,” he says.
The intentionally added substances are higher mostly because chemicals are added to restore the plastic’s functionality. Non-intentionally added substances can include everything from citrus compounds from drinks to flame retardants and heavy metals, says Bremer, and it’s not always obvious where they come from. “Who knows what was stored in that bottle before it was put out at the kerb? The bottom line is that thousands of things can and have been found in recycled plastic.”
The contaminants can impart flavour or odour, or reduce a food’s shelf life, he says. “Some substances that have been found are classified as substances of very high concern that are predicted to cause birth defects or are carcinogens, for example.” He agrees many of the substances have the potential to migrate from plastic into the food it packages, and very few toxicity studies have been carried out on them. “There’s far more that’s unknown than what’s known.”
But, says Bremer, solutions exist. One is using uncontaminated waste streams, which are easier to get from industrial than domestic recycling. The second is rules or codes that ensure decontamination processes work and are robustly tested, as is the case in the EU. “New Zealand is currently behind in this space.”
The Pact Group tests for chemicals migrating into food from its recycled PET packaging made in Lower Hutt, and no concerning migrations have been found. “We do way beyond what’s required in New Zealand,” says technical manager Mike Thrupp.
Bremer thinks the health risk from recycled plastic is low, and that the greater risk is harm to New Zealand’s export reputation if contaminant traces are detected in our products. Chemicals are more prone to migrating into food stored in packaging for a long time, such as during shipping, and if the food has a high fat content, as in some meat and dairy products.
Hormones & sperm counts
Not everyone agrees the health risk is low. Food safety rules deem chemicals to be safe below a certain level unless proven otherwise. Some scientists plead for a precautionary approach that considers them dangerous until proven safe. They may be vindicated only after years of accumulating evidence of harm. For example, decades after scientists began raising red flags on the plasticising chemical bisphenol A (BPA), the European Food Safety Authority is proposing a new total daily allowance of BPA that is 20,000 times lower than it recommended just eight years ago. Like phthalates, which are also plasticising chemicals, BPA disrupts hormone signalling, which influences multiple body systems. Such plasticisers are linked to dramatically lower semen quality. Sperm counts have more than halved since 1973 among men in North America, Europe, Australia and New Zealand, a 2017 study found.
New Zealand Food Safety (NZFS) doesn’t test for BPA but is considering doing so. Vince Arbuckle, the agency’s head, says the health risk from chemicals in plastics is negligible. By law, the onus here is on food producers to ensure their packaging is safe, and producers will also require assurance from packaging manufacturers, he says.
Our regulations don’t require manufacturers to do migration testing, but most also make packaging for export that meets US or EU standards, which do require it. Chemicals used in packaging don’t have to be approved before use, but Arbuckle says the rules are sufficient to control that risk and the packaging industry works to ensure products are safe.
NZFS does regular surveillance testing of food for chemical risks, he says. “There are maximum levels for all known chemical and microbiological risks, and these levels are conservatively set. We see no evidence of a problem.”
But the surveillance happens only every few years, and the few non-agricultural contaminants it includes represent very few of the chemicals that could migrate into food from plastic packaging.
Rachel Barker, CEO of Plastics NZ, says recycled food packaging in this country often has a layer of virgin plastic to prevent contamination. Most of our clear PET (No 1) plastic is recycled onshore or in Australia.
“You need the history of the plastic. With Coke bottles, for example, it’s easy to tell what they’ve been used for,” she says.
New Zealand doesn’t yet have the technology to recycle milk bottles back into food-grade packaging. If they’re lumped in with other No 2 plastics such as shampoo and cleaning bottles, they lose their value, because so-called “janitorial” plastics can absorb scents and are coloured.
Barker says it’s important we start designing products for longevity, repair or reuse. Plastics, she says, remain essential to our quality of life and low-carbon future, “but we need to use them more responsibly. We can’t change systems overnight, but we need to act fast. Even before the recent bans [on single-use plastics], 95% of our packaging manufacturers were already moving away from hard-to-recycle materials.”
She says new recycling technologies, new plants and plant upgrades will allow more plastic waste to be turned into usable objects. She points to recycled soft plastic going into construction board and fence posts, and the demand for polypropylene to make recycling bins, pipe culverts and paving stabilisation mats. Polystyrene packaging becomes insulation products, and guttering becomes new guttering.
Microplastics everywhere
Growing the recycling capacity instead of turning off the plastic production tap concerns many scientists. Olga Pantos, of crown research institute ESR, and environmental chemist Grant Northcott are leading a five-year study into the impact of microplastics on our ecosystems, animals and people, funded by the Ministry for Business, Innovation and Employment. They say plastic, whether virgin or recycled, leaches microplastics and chemicals.
“We don’t need plastic posts, for example – there is simply no decent amount of research done on these things, especially as they age and weather,” says Pantos. While the manufacturers mean well, she says New Zealand lacks regulation or guidance on appropriate testing.
She describes how metals are used as catalysts to make various plastic types, and they stay in the plastic along with other chemicals. “This stuff just hangs in there after recycling and it gets sloughed off with microplastics, but now you’ve put them in places where they wouldn’t otherwise have been, like where food is grown. If you’re drilling or cutting into these things, millions of microplastics spray around.”
The researchers have found microplastics in every beach and ocean sample, including Fiordland’s outer sounds. The tiny fragments were in compost, worm castings and soils irrigated with wastewater effluent.
The team could detect microplastics smaller than a hair strand’s diameter. “We found thousands of these particles to a kilo of sand,” says Pantos. “That’s getting down to the size scientists are very concerned about. They can be assimilated by the body, absorbed into lungs and taken up through the gut lining. When they’re very small they can enter cells. And wherever they go, they carry their chemical passengers with them.”
Hassan Wong is general manager of Future Post, which recycles most of what’s collected from the Soft Plastic Recycling Scheme, as well as many hard plastic products. He acknowledges his company’s recycled plastic posts have not been tested for leaching chemical additives. Some microplastic testing has just been done, he said, which showed none, but the details were not yet available.
Wong says that if his company’s posts shed microplastics, the scale would be minuscule compared with what’s created by washing synthetic clothes, tyres wearing on roads, and litter. He points out that the main alternative is treated timber posts that release copper, chromium and arsenic. This treatment is banned or restricted in Australia, the US and the European Union. Here, there are calls to replace it with safer preservatives.
Future Post doesn’t release water from its plant. “No product has a zero environmental impact, but if we’re looking at it on a net-benefit basis, I think Future Posts stack up well,” says Wong. “Last year, we recycled over 550 tonnes of post-residential soft plastics. There is no other option for this waste – it would end up in the tip and degrade there. But in a post, it’s encapsulated, so there’s dramatically less surface area than in the underlying product. Most of a post’s plastic is locked away from the UV light that degrades it.” A UV stabilising chemical is added.
Leachate from New Zealand landfills can be sprayed on forestry land, but is unlikely to be sprayed on food-producing land, according to WasteMinz, which represents Aotearoa’s waste, resource recovery and contaminated land sectors.
Plastic in municipal landfills is also protected from light because the rubbish is capped daily. It still degrades, but landfills are lined and the leachate is collected. Leachate is often sent to wastewater treatment plants, which break down some but not all chemical compounds and remove some microplastics.
Wastewater from a state-of-the-art UK recycling plant was recently found to contain microplastics amounting to 13% of the plastic being processed. Installing a filter reduced the volume of microplastics in the wastewater to 6% – but this still meant an estimated 75 billion particles per cubic metre of wastewater could be released.
Breaking it down
Could compostable plastics help? One of the most promising is PHA (polyhydroxyalkanoate, a polyester derived from microorganisms). It’s truly compostable, says environmental chemicst Northcott. “Bacteria can use several feedstocks to make PHA as their energy store. Then, at the end of its life, bacteria easily break it down to its mineral components, even in the sea.” Another compostable plastic, PLA, or polylactic acid, is also made partly by fermentation but needs very specific conditions to break down, he says.
Scion, based in Rotorua, houses Australasia’s only lab accredited to test plastic compostability. Kate Parker leads the team that does it. She says the tests check whether microbes break down the plastic and whether it disintegrates quickly and thoroughly in conditions that mimic industrial or home-composting conditions.
Industrial composting is hotter and faster, and it’s the only way certified compostable PLA-lined coffee cups can be composted. However, industrial composters often accept compostable products only from approved waste collectors, not individuals, or cannot accept them at all.
Compostable plastic also often contains additives to improve the way it looks and performs. “Manufacturers can add ingredients at up to a 5% level that aren’t compostable, so there is a possibility that detrimental things can be there,” says Parker. “We do ecotoxicity testing on the compost made … to check seedlings still germinate and worms are not harmed. We also test for PFAS [per- and polyfluoroalkyl substances, a toxic so-called forever chemical that’s prevalent in the environment and our bodies] and heavy metals, which usually come from inks and adhesives.” PFAS is a known concern in compostable packaging.
Scion performs the tests and sends the results to a certifying body. But certification doesn’t require tests for bioaccumulation or long-term impacts on soil health.
Currently, compostable plastics are usually made from maize. But Scion can make PHA from waste products such as wood leftovers and methane. “We’ve made PHA polymers from wood sugars in a bioreactor, and we’re exploring with commercial parties how to scale that up,” says Scion’s Alec Foster. It’s even possible to recycle PHA, he says, and if it’s done using enzymes it can be done an unlimited number of times. He sees it as an ideal solution where plastic will get dirty: medical, farming and food applications.
The hitch is that oil-based plastics are about half the price. “Customers will pay 10% more for more sustainable solutions, but not double,” says Foster. “But global regulations are changing, especially in the EU, and you’re going to have to meet them if you’re an exporter. So lots of companies are anticipating change.”
Turning off the tap
Top-down direction may be the only way out of this mess. A Global Plastics Treaty is expected to be negotiated by late 2024. The intention is a binding multinational agreement addressing pollution across all stages of plastic’s life, from minimising fossil fuel extraction to remediating polluted ecosystems. If the 300-strong coalition of scientists involved have their way, the treaty will end the production of plastics unless they are independently assessed as safe and sustainable, or critical for the health, safety and functioning of society.
The coalition is a broad church that includes indigenous representatives and those living on the frontlines of plastic pollution. Massey University anthropologist Trisia Farrelly sits on its steering committee. “The process so far has been dominated by polluting industry, so the negotiating countries requested the scientists’ coalition to provide independent scientific support.”
Farrelly is constantly disappointed by messages blaming time- and resource-poor families for consuming plastic and not recycling enough. “That diverts attention away from the powerful players who profit from it and externalise the costs. In fact, the No 1 challenge is redesigning materials, chemicals, products and indeed the whole system.”
Another representative at the negotiations is Matt Peryman of Ngāti Awa, who co-ordinates the Tāngata Whenua Coalition for an Effective Plastics Treaty. He’s seen that industry players don’t want to talk about decreasing production. “Recycling is the predominant narrative. It’s so frustrating. We need to find ways of reducing plastic waste in the first place.
“The system at the moment is linear and everything is dumped on land or into the ocean and air. That jars with our intergenerational world view and the long-term effects on our whakapapa.”
Peryman has seen the power of Māori-led solutions. “Everyone talks about the circular economy as if it’s a new phenomenon. But circularity existed in all indigenous societies – it was the only way we could survive, by careful resource use. We never made things that weren’t biodegradable. Our tikanga prevents over-extraction. What local materials can we use?
“Māori in particular are receptive to this. Having seen the environmental degradation over many generations, we’re motivated by that to push for change. Our connection with nature is still there, as are the old ways that help guide us.”
‘A revolution needs to happen’
Liam Prince has been called the Compost King of Aotearoa. He’s a compost manager at Kaicycle, an urban farm and composting enterprise in central Wellington that sells produce grown using compost made from locally collected food scraps. Kaicycle won’t accept any compostable packaging. “We’ve fished out stuff that’s supposedly home compostable,” he says. “We’re not sure what it’s leaving behind in the soil. There are thousands of chemicals that can be included, and there are no regulations around labelling.”
Scion scientists agree that labelling can be baffling. Plastic can legally be labelled as biodegradable, which means only that it breaks down into progressively smaller pieces, but this could take 50 years.
Another stonker is “biobased”, meaning it’s made from something other than fossil fuels – which could be food crops – and may or may not be compostable. Certified compostable products should, but don’t have to, display which certification they meet (eg, AS 5810) and whether that means they are home or industrially compostable.
The Packaging Forum, which represents the packaging industry, is proposing labelling regulations as part of a product stewardship scheme.
Plastic chemicals worry Prince. “The planet is already being affected on a systemic level and plastic production is projected to treble. This is a threat to planetary health that’s at least as serious as climate change.”
Leading scientists agree. A paper published last month in Science Advances described how far more “novel entities” are being released than the planet can cope with. “With such an enormous percentage of untested chemicals being released to the environment, a novel entities boundary … is clearly breached,” wrote the authors.
Prince’s other beef with compostable plastics is that they enable society’s single-use culture.
“A revolution needs to happen – not just people bringing their own cups, but logistical systems to enable businesses to use reusables much as they use single-use products.” He points to reuse schemes listed on the Takeaways Throwaways website. “If the government will send the right signals, and we have an honest conversation about the true costs of single-use, then businesses will innovate.”
Not sorted
A proportion of the plastics we put out for recycling still ends up in landfill.
There was a shudder in the suburbs during Covid lockdowns. “Our recycling is just going to be landfilled!” called horrified neighbours across the lawn. It was true. Roadside collections were paused, so committed residents stashed recyclables in their garages. But recycling centre operators weren’t allowed to work during level 4 restrictions.
Barney Irvine co-ordinates the Waste & Industry Recycling Forum, which represents the companies that collect and recycle or dispose of New Zealand’s waste. He says recycling companies were also wary of their workers catching Covid from handling contaminated items. But once the lockdown eased, recycling restarted.
These days about 80% of the plastic in household recycling bins is recycled and the rest is landfilled. Those are rough estimates, says Irvine, as data is lacking.
One reason for the landfilled proportion is contamination of the recycling stream with non-recyclable items. These could be things with no prospect of being recycled – dirty nappies, dog poo or even dead animals – or simply unrinsed milk or cream bottles. Most recycling is sorted manually, and workers must touch and smell our castoffs.
Irvine also rues all the disposable coffee cups that end up in recycling bins. Many are assumed to be recyclable but cannot be processed by recyclers. He wishes people would err on the side of caution when it comes to recycling. “There’s a big difference between theoretically recyclable and practicably recyclable.”
Recycling sorters run businesses with slim margins, and they need a market for the plastic or it goes to the dump. “One example is coloured PET bottles, such as juice bottles – there’s currently no market here or offshore,” says Irvine. That’s why Sprite bottles are now clear instead of green. “Recyclers constantly play the game of trying to find markets. There can be huge fluctuations on both the supply and demand side for recyclable material.”
From next February, we’ll have clearer, countrywide rules about what councils can accept for recycling. When it comes to plastic, that means only bottles and containers with recycling symbols 1, 2 and 5. But if there’s no market or a bale of plastic is contaminated with non-recyclables, the landfill will still beckon.