We estimate there are up to 14 million tonnes of microplastics on the seafloor. It’s worse than we thought



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Britta Denise Hardesty, CSIRO; Chris Wilcox, CSIRO, and Justine Barrett, CSIRO

Nowhere, it seems, is immune from plastic pollution: plastic has been reported in the high Arctic oceans, in the sea ice around Antarctica and even in the world’s deepest waters of the Mariana Trench.

But just how bad is the problem? Our new research provides the first global estimate of microplastics on the seafloor — our research suggests there’s a staggering 8-14 million tonnes of it.

This is up to 35 times more than the estimated weight of plastic pollution on the ocean’s surface.

What’s more, plastic production and pollution is expected to increase in coming years, despite increased media, government and scientific attention on how plastic pollution can harm marine ecosystems, wildlife and human health.

These findings are yet another wake-up call. When the plastic we use in our daily lives reaches even the deepest oceans, it’s more urgent than ever to find ways to clean up our mess before it reaches the ocean, or to stop making so much of it in the first place.

Breaking down larger plastic

Our estimate of microplastics on the seafloor is huge, but it’s still a fraction of the amount of plastic dumped into the ocean. Between 4-8 million tonnes of plastic are thought to enter the sea each and every year.




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Eight million tonnes of plastic are going into the ocean each year


Most of the plastic dumped into the ocean likely ends up on the coasts, not floating around the ocean’s surface or on the seafloor. In fact, three-quarters of the rubbish found along Australia’s coastlines is plastics.

A dead albatross with plastic in its stomach from Midway Atoll
Plastic including toothbrushes, cigarette lighters, bottle caps and other hard plastic fragments are found in the stomachs of many marine species.
Britta Denise Hardesty

The larger pieces of plastic that stay in the ocean can deteriorate and break down from weathering and mechanical forces, such as ocean waves. Eventually, this material turns into microplastics, pieces smaller than 5 millimetres in diameter.

Their tiny size means they can be eaten by a variety of marine wildlife, from plankton to crustaceans and fish. And when microplastics enter the marine food web at low levels, it can move up the food chain as bigger species eat smaller ones.

But the problem isn’t as well documented for microplastics on the seafloor. While plastics, including microplastics, have been found in deep-sea sediments in all ocean basins across the world, samples have been small and scarce. This is where our research comes in.

Collecting samples in the Great Australian Bight

We collected samples using a robotic submarine in a range of sea depths, from 1,655 to 3,062 metres, in the Great Australian Bight, up to 380 kilometres offshore from South Australia. The submarine scooped up 51 samples of sand and sediment from the seafloor and we analysed them in a laboratory.

Sampling of deep sea sediments took place using an underwater robot.
CSIRO, Author provided

We dried the sediment samples, and found between zero and 13.6 plastic particles per gram. This is up to 25 times more microplastics than previous deep-sea studies. And it’s much higher than studies in other regions, including in the Arctic and Indian Oceans.

While our study looked at one general area, we can scale up to calculate a global estimate of microplastics on the seafloor.

Using the estimated size of the entire ocean — 361,132,000 square kilometres — and the average number and size of particles in our sediment samples, we determined the total, global weight as between 8.4 and 14.4 million tonnes. This range takes into account the possible weights of individual microplastics.

How did the plastic get there?

It’s important to note that since our location was remote, far from any urban population centre, this is a conservative estimate. Yet, we were surprised at just how high the microplastic loads were there.

Plastic waste floating in the ocean
Areas with floating rubbish on the ocean’s surface have plastic on the seafloor.
Shutterstock

Few studies have conclusively identified how microplastics travel to their ultimate fate.

Larger pieces of plastic that get broken down to smaller pieces can sink to the seafloor, and ocean currents and the natural movement of sediment along continental shelves can transport them widely.

But not all plastic sinks. A 2016 study suggests interaction with marine organisms is another possible transport method.

Scientists in the US have shown microbial communities, such as bacteria, can inhabit this marine “plastisphere” — a term for the ecosystems that live in plastic environments. The microbes weigh the plastic down so it no longer floats. We also know mussels and other invertebrates may colonise floating plastics, adding weight to make them sink.




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Plastic pollution creates new oceanic microbe ecosystem


The type of rubbish will also determine whether it gets washed up on the beach or sinks to the seafloor.

For example, in a previous study we found cigarette butts, plastic fragments, bottlecaps and food wrappers are common on land, though rare on the seabed. Meanwhile, we found entangling items such fishing line, ropes and plastic bags are common on the seafloor.

Microplastics at the water's edge
We were surprised at just how high the microplastic loads were in such a remote location.
CSIRO

Interestingly, in our new study we also found the number of plastic fragments on the seafloor was generally higher in areas where there was floating rubbish on the ocean’s surface. This suggests surface “hotspots” may be reflected below.

It’s not clear why just yet, but it could be because of the geology and physical features of the seabed, or because local currents, winds and waves result in accumulating zones on the ocean’s surface and the seabed nearby.

Stop using so much plastic

Knowing how much plastic sinks to the ocean floor is an important addition to our understanding of the plastic pollution crisis. But stemming the rising tide of plastic pollution starts with individuals, communities and governments – we all have a role to play.

Reusing, refusing and recycling are good places to start. Seek alternatives and support programs, such as Clean Up Australia Day, to stop plastic waste from entering our environment in the first place, ensuring it doesn’t then become embedded in our precious oceans.




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The oceans are full of our plastic – here’s what we can do about it


The Conversation


Britta Denise Hardesty, Principal Research Scientist, Oceans and Atmosphere Flagship, CSIRO; Chris Wilcox, Senior Principal Research Scientist, CSIRO, and Justine Barrett, Research assistant, CSIRO

This article is republished from The Conversation under a Creative Commons license. Read the original article.

The ocean is swimming in plastic and it’s getting worse – we need connected global policies now



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Steve Fletcher, University of Portsmouth and Keiron Philip Roberts, University of Portsmouth

It seems you cannot go a day without reading about the impact of plastic in our oceans, and for good reason. The equivalent of a garbage truck of plastic waste enters the sea every minute, and this increases every day. If we do nothing, by 2040 the amount of plastic entering the ocean will triple from 13 million tonnes this year, to 29 million tonnes in 2040. That is 50kg of waste plastic entering the ocean for every metre of coastline.

Add to that almost all the plastic that has entered the ocean is still there since it takes centuries to break down. It is either buried or broken down into smaller pieces and potentially passes up the food chain creating further problems.

Despite this, plastic has also been a saviour. During the COVID-19 pandemic plastic used in face masks, testing kits, screens and to protecting food has enabled countries to come out of lockdown during and support social distancing. We still need to use these items until sustainable and “COVID safe” alternatives are available. But we also need to look to the future to reduce our dependence on plastic and its impact on the environment. With plastic in the ocean being a global problem, we need global agreements and policies to reverse the plastic tide.




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Ambitious policies are needed

Environment ministers of the G20 group of the world’s most economically powerful countries and regions met on September 16 to discuss their immediate challenges, with marine plastic pollution a top priority. A key item for discussion was “safeguarding the planet by fostering collective efforts to protect our global commons”. This means working out how we can continue to use the planet’s resources sustainably without harming the environment.

A global analysis of plastics policies over the past two decades found that typical reactions to marine plastic litter were bans or taxes on individual or groups of plastic items within single countries. So far, 43 countries have introduced a ban, tax or levy on plastic bags. Other plastic packaging or single-use plastic products were banned in at least 25 countries, representing a population of almost 2 billion people in 2018.

But plastic waste doesn’t respect land or ocean borders, with mismanaged plastic waste easily migrating from country to country when leaked into the environment. Policies also need to consider the entire plastics life cycle to stand a chance of being effective. For example, the inclusion of easier to recycle plastics in consumer products sounds positive, but their actual recycling rate depends on effective sorting and collection of plastic waste, and appropriate infrastructure being in place.




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Ultimately, a joined up but adaptable set of rules and guidelines are needed so all plastic producers and users can prevent its leakage across all stages of the plastics life cycle.

The G20 has sought to lead action on marine plastic litter through a 2017 Action Plan on Marine Litter which set out areas of concern and possible policy interventions, and through connections to initiatives such as the UN Environment Programme’s Global Partnership on Marine Litter and most recently the Osaka Blue Ocean Vision. The Osaka vision was agreed under the Japanese G20 presidency in 2019 and commits countries to “reduce additional pollution by marine plastic litter to zero by 2050”. Although an agreement led by the G20, it now has the support of 86 countries.

But even with these agreements in place, plastic entering the ocean will still only reduce by 7% by 2040. We need ambitious new agreements as current and emerging policies do not meet the scale of the challenge.

A consensus is forming that the G20 and other global leaders must focus on a systemic change of the plastics economy. This includes focusing on “designing out” plastics, promoting technical and business innovation, immediately scaling up actions known to reduce marine plastic litter, and transitioning to a circular economy in which materials are fully recovered and reused. These actions have the potential to contribute to the G20’s vision of net-zero plastics entering the ocean by 2050, but only if ambitious actions are taken now.The Conversation

Steve Fletcher, Professor of Ocean Policy and Economy, University of Portsmouth and Keiron Philip Roberts, Research Fellow in Clean Carbon Technologies and Resource Management, University of Portsmouth

This article is republished from The Conversation under a Creative Commons license. Read the original article.

We composted ‘biodegradable’ balloons. Here’s what we found after 16 weeks



‘Biodegradable’ balloons after 16 weeks in freshwater.
Jesse Benjamin, Author provided

Morgan Gilmour, University of Tasmania and Jennifer Lavers, University of Tasmania

After 16 weeks in an industrial compost heap, we unearthed blue and white balloons and found them totally unscathed. The knots we spent hours painstakingly tying by hand more than four months ago were still attached, and sparkly blue balloons still glinted in the sun.

These balloons originally came from packages that advertised them as “100% biodegradable”, with the manufacturers assuring they were made of “100% natural latex rubber”. The implication is that these balloons would have no trouble breaking down in the environment.




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This appeals to eco-conscious consumers, but really just fuels corporate greenwashing — unsubstantiated claims of environmentally friendly and safe products.

Holding perfectly intact balloons in our hands after four months in industrial compost, we had cause to question these claims, and ran experiments.

What’s the problem?

This problem is two-fold. First, balloons are additional plastic waste in the environment. They are lightweight and can travel on air currents far from the point of release. For example, one 2005 study found a balloon travelled more than 200 kilometres.

alt text
Not much changed after 14 weeks.
Morgan Gilmour, Author provided

When they pop, they float back to the earth’s surface and land in, for example, the ocean or the desert, and wash up on beaches where animals can eat them, from sea turtles and seabirds to desert tortoises.

The stretchiness of balloons means they can get stuck in animals’ digestive tracts, which will cause choking, blockage, decreased nutrient absorption and effectively starve the animal.




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Second, what most consumers don’t realise, is that to shape milky natural rubber latex sap into the product we know as a balloon, many additional chemicals need to be added to the latex.

These chemicals include antioxidants and anti-fogging (to counteract that cloudy look balloons can get), plasticisers (to make it more flexible), preservatives (to enable the balloon to sit in warehouses and store shelves for months), flame retardants, fragrance and, of course, dyes and pigments.

Even more chemicals have to be used to make the additives “stick” to the latex and to stick to each other, enabling them to work in tandem to create a product we expect to use for about 24 hours. So, the balloons can’t be “100% natural rubber latex”.

A little girl on a park bench lets go of a pink balloon
Balloons can travel vast distances in the sky before they pop and are eaten by animals.
Unsplash, CC BY

And yet, despite substantial evidence of harm and the presence of these chemicals, balloon littering persists. Balloon releases are common, with only some regional regulations in place, such as in New South Wales and the Sunshine Coast.

Lying for decades

While some factions of the balloon industry denounce balloon releases, these claims are only recent.

For decades, the industry relied on one industry-funded study from 1989 which claimed that after six short weeks, balloons degraded “at about the same rate as oak tree leaves” and there was no way balloons were a threat to wildlife.

That study was not peer-reviewed, its methods are unclear and not repeatable, and the results are based on only six balloons.




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Because balloons are frequently reported to be at sea, ingested by wild animals and washed up on beaches, it’s clear they’re not breaking down in only six weeks. Anecdotal studies have tested this to varying degrees, confirming balloons don’t break down.

Only one peer-reviewed scientific study has quantified balloon degradation, and that also occurred in 1989 — the same year as the industry study. They tested elasticity for up to one year, which means the balloons were intact for that whole time.

Person with a rake buries blue latex balloons in the compost
We tested the claims of the balloon industry.
Dahlia Foo, Author provided

We wanted to know: has anything changed since 1989? And why aren’t there more studies testing balloon degradation, given the passion behind the balloon issue?

So, we set out to quantify exactly how long latex balloons would take to break down. And we asked if balloons degraded differently in different parts of the environment.

Our experiment tested their claims

Industrial composting standards require that the material completely disintegrates after 12 weeks and that the product is not distinguishable from the surrounding soil.

We designed an experiment: after exposing balloons to six hours of sunlight (to simulate typical use, for example, at an outdoor party), we put blue and white balloons in industrial compost, and in saltwater and freshwater tanks.

We allowed for aeration to simulate natural conditions, but otherwise, we left the balloons alone. Every two weeks, we randomly removed 40 balloons from each treatment. We photographed them to document degradation. Then we tested them.

The author prepares to sample latex balloons in front of water tanks
The author sampling latex balloons.
Jesse Benjamin, Author provided

Were the balloons still stretchy? We tested this in the University of Tasmania engineering lab to determine tensile (resistence) strength. We found that in water tanks, the balloons became less stretchy, losing around 75% of their tensile strength. But if they had been composted, balloons retained their stretchiness.

Were the balloons still composed of the same things they started with? We tested this by taking spectral measurements of the balloons’ surface. The balloons showed signs they were exposed to ultra violet light in the water tanks, but not in the compost. This means their chemical composition changed in water, but only slightly.

Finally, and most importantly, did the balloons lose mass?

After 16 weeks, the balloons were still recognisably balloons, though they behaved a little differently in compost, water and saltwater. Some balloons lost 1–2% mass, and some balloons in freshwater gained mass, likely due to osmotic absorption of water.

Four dirty, deflated white balloons in a row on a black background.
These are white latex balloons 16 weeks after we composted them.
Jesse Benjamin, Author provided

What can we do?

It’s clear latex balloons don’t meaningfully degrade in 16 weeks and will continue to pose a threat to wildlife. So what can we do as consumers? We offer these tips:

  • do not release balloons outdoors
  • do not use helium-filled balloons outdoors (this prevents accidental release, and saves helium), which is a critically limited resource
  • if you use balloons, deflate and bin them after use
  • consider balloon alternatives, like bubbles
  • make educated purchases with federal Green Guidelines in mind.



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There are some single-use plastics we truly need. The rest we can live without


The Conversation


Morgan Gilmour, Adjunct Researcher in Marine Science, University of Tasmania and Jennifer Lavers, Lecturer in Marine Science, University of Tasmania

This article is republished from The Conversation under a Creative Commons license. Read the original article.

How Earth’s plastic pollution problem could look by 2040



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Costas Velis, University of Leeds and Ed Cook, University of Leeds

During a visit to a bookstore a few weeks ago, we couldn’t help but stare at a display unit featuring no fewer than ten books telling you how to rid plastics from your daily life. We’re bombarded by information on the topic of marine litter and plastic pollution, but how much do we really know about the problem?

Think about other planetary challenges, like climate change or ozone layer depletion. Mature areas of research have developed around them, allowing scientists to identify where the gases that cause these problems come from, and how much reaches the atmosphere each year.

But when it comes to plastic pollution, we know close to nothing about how and where plastic waste is generated, managed, treated and disposed of, especially in low and middle income countries. As a result, we’re struggling to limit the amount of litter accumulating in the environment.

Our research published in Science involved a herculean effort to spot, track and model the current and future flows of plastics into the world’s land and waterbodies. We found that plastic entering the marine environment is set to double by 2040 and, unless the world acts, more than 1.3 billion tonnes of plastic waste will be dumped on land and in waterbodies.

By identifying the ways in which this litter is produced and distributed, we’ve also discovered how best to reduce the plastic deluge. In the process, we found the unsung heroes on the frontline fighting the pollution crisis who could be the world’s best hope of stemming the tide.

Discarded face masks on a rocky beach.
Single-use plastic consumption has increased during the pandemic.
Fevziie/Shutterstock

The world’s plastic problem in numbers

We developed a model called Plastic-to-Ocean (P₂O) which combines years of accumulated knowledge on global flows of plastic. It compares our current production, use and management of waste with what is projected in the future.

Do you burn your waste in the garden or in the street? Do you drop it into the river? If you answered no to both of these questions then you are possibly one of the 5.5 billion people whose waste gets collected. If you were among the remaining two billion, what would you do with your uncollected waste? Would you make use of a nearby stream, cliff edge, or perhaps squirrel the odd bag in the woods after dusk?

More often than not, uncollected plastic waste is simply set on fire as a cost-free and effective method of disposal. Our model suggests that cumulatively, more than 2.2 billion tonnes of plastic will be open burned by 2040, far more than the 850 million tonnes that’s anticipated to be dumped on land and the 480 million tonnes in rivers and seas.

Having tracked the sources of plastic items through the supply chain and their fate in the environment, we explored what might help reduce aquatic pollution. We found that the single most effective intervention is to provide a service for the two billion people who currently don’t have their waste collected.

A graph showing how different measures could reduce the flow of plastic into the ocean.

Breaking the Plastic Wave, Author provided

But, of the nine interventions we tested, none solved the problem on their own. Only an integrated approach that in addition to increasing collection coverage includes interventions such as reducing demand for single-use and unrecyclable plastic and improving the business case for mechanical recycling, could be successful. For the countries suffering most from plastic pollution, this knowledge could offer a way forward.

But even in our best-case scenario, in which the world takes the kind of concerted and immediate action proposed in our study, approximately 710 million tonnes of plastic waste will be released into the environment by 2040. That may sound a lot, but it would mean an 80% reduction in the levels of plastic pollution compared to what will happen with no action over the next two decades.




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Could waste pickers save the day?

Our work also cast light on the contributions of 11 million waste pickers in low and middle-income countries. These informal workers collect waste items, including plastics, for recycling, to secure a livelihood for day-to-day survival. The model estimates that they may be responsible for 58% of all plastic waste collected for recycling worldwide – more than the combined formal collection services achieve throughout all the high-income countries put together.

Without this informal waste collection sector, the mass of plastic entering rivers and the ocean would be considerably greater. Their efforts should be integrated into municipal waste management plans, not only to recognise their tremendous contribution but to improve the appalling safety standards that they currently endure.

A man in India peddles a bicycle cart to collect rubbish.
An additional 500,000 people will need to be reached by waste collection services each day until 2040.
EPA-EFE/JAIPAL SINGH

Establishing a comprehensive baseline estimate of sources, stocks and flows of plastic pollution, and then projecting into the future, has been an immense task. When it comes to solid waste, the availability, accuracy and international compatibility of data is notoriously insufficient.

Plastic items occur throughout the world in tens of thousands of shapes, sizes, polymer types and additive combinations. There are also considerable differences in cultural attitudes towards the way waste is managed, how plastic products are consumed, and the types of infrastructure and equipment used to manage it when it becomes waste.

Our modelling effort was a delicate and tedious exercise of simplifying and generalising this complexity. To understand how reliable, accurate, and precise our findings are likely to be, think of the first models that estimated how sensitive the climate is to human influence back in the 1970s.

Hopefully, the strong evidence base we have presented today will inform a global strategy and strong local preventive action. The plastic pollution challenge can be substantially controlled within a generation’s time. So, is anyone ready to act?The Conversation

Costas Velis, Lecturer in Resource Efficiency Systems, University of Leeds and Ed Cook, Research Fellow in Circular Economy Systems, University of Leeds

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Avoiding single-use plastic was becoming normal, until coronavirus. Here’s how we can return to good habits



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Kim Borg, Monash University; Jim Curtis, Monash University, and Jo Lindsay, Monash University

As COVID-19 restrictions start to ease, we’re unlikely to return to our previous behaviours, from our work-life balance to maintaining good hygiene.

But there are downsides to this new normal, particularly when it comes to hygiene concerns, which have led to an increase in an environmental scourge we were finally starting to get on top of: single-use plastics.

We’ve recently published research based on data collected in mid-2019 (before COVID-19). Our findings showed that not only were people avoiding single-use plastics most of the time, but one of the biggest motivators was knowing others were avoiding them too. Avoidance was becoming normal.




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But then COVID-19 changed the game. Since the pandemic started, there has been a significant increase in plastic waste, such as medical waste from protective equipment such as masks, gloves and gowns, and increased purchases of sanitary products such as disposable wipes and liquid soap.

The good news is we can return to our plastic-avoiding habits. It just might look a little a different.

As we needed to protect ourselves with masks, we added to the waste crisis.
Shutterstock

Avoidance was more normal than we realised

In our representative survey of 1,001 Victorians, we asked people about their behaviours and beliefs around four single-use plastic items: bags, straws, coffee cups and take-away containers.

We found people’s beliefs about how often others were avoiding these items was one of the strongest predictors of their own intentions.

Other influences that predicted intentions included personal confidence, the perceived self and environmental benefits and financial costs associated with avoidance, and whether others would approve or disapprove of the behaviour.




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While beliefs about other peoples’ behaviour was one of the strongest predictors of intentions, there was still a gap between these beliefs and reported behaviour.

On average, 70% of our sample reported avoiding single-use plastics most of the time. But only 30% believed others were avoiding them as often.

Thankfully, our findings suggest we can encourage more people to avoid single-use plastics more often by sharing the news that most people are doing it already. The bad news is that COVID-19 has increased our reliance on single-use items.

Some single-use is necessary during a pandemic

Just when avoidance was becoming normal, the pandemic brought single-use plastics back into favour.

Despite the fact the virus survives longer on plastic compared to other surfaces and a lack of evidence that disposable items are any safer than reusable ones, many businesses are refusing to accept reusable containers, such as coffee cups.

Cafes have refused reusable cups to try to maintain better hygiene.
Shutterstock

Overseas and in Australia, some government departments delayed upcoming bans on single-use plastics and others overturned existing single-use plastic bag bans.

So even if consumers want to avoid single-use plastics, it’s not as easy as it used to be.

Avoiding plastic can still be part of the new normal

It is still possible to avoid unnecessary single-use plastic right now. We just need to get creative and focus on items within our control.

We can still pack shopping in reusable bags, make a coffee at home in a reusable cup, carry reusable straws when we go out – just make sure to wash reusables between each use.




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Many Victorians can even order delivery take-away food in reusable containers, thanks to the partnership between Deliveroo and Returnr, the reusable packaging scheme. Boomerang Alliance also produced guidelines for sustainable take-away options, including practical tips for contactless transfer of food.

Our research focused on public single-use plastic avoidance behaviours, but now is a good time to look at private ones too.

There are plenty of single-use plastics in the home: cling wrap, coffee pods, shampoo and conditioner bottles, disposable razors and liquid soap dispensers to name a few.

Using reusable wraps for your food is a much better alternative than single-use cling wrap.
Shutterstock

But you can find reusable alternatives for almost everything: beeswax or silicone wraps, reusable coffee pods, shampoo and conditioner bars, reusable safety razors and bars of soap, rather than liquid soap.

Buying cleaning products in bulk can also reduce plastic packaging and keeping glass jars or hard plastic containers are great for storing leftovers.




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There are some single-use plastics we truly need. The rest we can live without


Just because we’re in a period of change, doesn’t mean we have to lose momentum. Single-use plastics are a huge environmental problem that we can continue to address by changing our behaviours.

Many are calling on governments, businesses and individuals to use the pandemic as an opportunity to look at how we used to do things and ask – is there a better way?

When it comes to single use plastics during COVID-19, we can’t control everything. But our actions can help shape what the new normal looks like.The Conversation

Kim Borg, Research Fellow at BehaviourWorks Australia, Monash Sustainable Development Institute, Monash University; Jim Curtis, Research Fellow in Behaviour Change, Monash University, and Jo Lindsay, Professor of sociology, Monash University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

More than 1,200 tonnes of microplastics are dumped into Aussie farmland every year from wastewater sludge


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Abbas Mohajerani, RMIT University

Every year, treated wastewater sludge called “biosolids” is recycled and spread over agricultural land. My recent research discovered this practice dumps thousands of tonnes of microplastics into farmlands around the world. In Australia, we estimate this amount as at least 1,241 tonnes per year.

Microplastics in soils can threaten land, freshwater and marine ecosystems by changing what they eat and their habitats. This causes some organisms to lose weight and have higher death rates.

But this is only the beginning of the problem. Microplastics are good at absorbing other pollutants – such as cadmium, lead and nickel – and can transfer these heavy metals to soils.

Wastewater treatment plants create biosolids, which are packed full of microplastics and toxic chemicals.
Shutterstock

And while microplastics alone is an enormous issue, other contaminants have also been found in biosolids used for agriculture. This includes pharmaceutical chemicals, personal care products, pesticides and herbicides, surfactants (chemicals used in detergents) and flame retardants.

We must stop using biosolids for farmlands immediately, especially when alternative ways to recycle wastewater sludge already exist.

Where do the microplastics come from?

Biosolids are mainly a mix of water and organic materials.

But many household items that contain microplastics – such as lotions, soaps, facial and body washes, and toothpaste – end up in wastewater, too. Other major sources of microplastics in wastewater are synthetic fibres from clothing, plastics in the manufacturing and processing industries, and the breakdown of larger plastic debris.

Before they’re taken to farmlands, wastewater collection systems carry all, or most, of these microplastics and other chemicals from residential, commercial and industrial sources to wastewater treatment plants.

To determine the weight of microplastics in Australia and other countries, my data analysis used the average minimum and maximum numbers of microplastics particles, per kilogram of biosolids samples, found in Germany, Ireland and the USA.




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Australia produced 371,000 tonnes of biosolids in 2019. And globally, we estimate between 50 to more than 100 million tonnes of biosolids are produced each year.

Why microplastics are harmful

Microplastics in soil can accumulate in the food web. This happens when organisms consume more microplastics than they lose. This means heavy metals attached to the microplastics in soil organisms can progress further up the food chain, increasing the risk of human exposure to toxic heavy metals.

When microplastics accumulate heavy metals, they transfer these contaminants to plants and crops, such as rice and grains, as biosolids are spread over farmland.




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Over time, microplastics break down and become even tinier, creating nanoplastics. Crops have also been shown to absorb nanoplastics and move them to different plant tissues.

Our research results also show that after the wastewater treatment process, the absorption potential of microplastics for metals increases.

The metal cadmium, for example, is particularly susceptible to microplastics in biosolids and can be transported to plant cells. Research from 2018 showed microplastics in biosolids can absorb cadmium ten times more than virgin microplastics (new microplastics that haven’t gone through wastewater treatment).

Biosolids have a cocktail of nasty chemicals

It’s not just plastic – many industrial additives and chemicals have been found in wastewater and biosolids.

This means they may accumulate in soils and affect the equilibrium of biological systems, with negative effects on plant growth. For example, researchers have found pharmaceutical chemicals in particular can reduce plant growth and inhibit root elongation.




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Other chemical contaminants – such as PFCs, PFAS and BPA – have likewise been detected in biosolids.

The effects these chemicals have on plants may lead to problems further down the food chain, such as humans and other animals inadvertently consuming pharmaceuticals and harmful chemicals.

What can we do about it?

Given the cocktail of toxic chemicals, heavy metals and microplastics, using biosolids in agricultural soils must be stopped without delay.

The good news is there’s another way we can recycle the world’s biosolids: turning them into sustainable fired-clay bricks, called “bio-bricks”.

Bricks incorporated with biosolids are a sustainable solution to an environmental problem.
RMIT media, Author provided

My team’s research from last year found bio-bricks a sustainable solution for both the wastewater treatment and brick manufacturing industries.

If 7% of all fired-clay bricks were biosolids, it would redirect all biosolids produced and stockpiled worldwide annually, including the millions of tonnes that currently end up in farmland each year.




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We also found they’d be more energy efficient. The properties of these bio-bricks are very similar to standard bricks, but generally requires 12.5% less energy to make.

And generally, comprehensive life-cycle assessment has shown biosolid bricks are more environmentally friendly than conventional bricks. These bricks will reduce or eliminate a significant source of greenhouse gas emissions from biosolids stockpiles and will save some virgin resources, such as clay soil and water, for the brick industry.

Now, it’s up to the agriculture, wastewater and brick industries, and governments to make this important transition.The Conversation

Abbas Mohajerani, Associate Professor, School of Engineering, RMIT University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

After a storm, microplastics in Sydney’s Cooks River increased 40 fold



A litter trap in Cook’s River.
James HItchcock, Author provided

James Hitchcock, University of Canberra

Each year the ocean is inundated with 4.8 to 12.7 million tonnes of plastic washed in from land. A big proportion of this plastic is between 0.001 to 5 millimetres, and called “microplastic”.

But what happens during a storm, when lashings of rain funnel even more water from urban land into waterways? To date, no one has studied just how important storm events may be in polluting waterways with microplastics.




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So to find out, I studied my local waterway in Sydney, the Cooks River estuary. I headed out daily to measure how many microplastics were in the water, before, during, and after a major storm event in October, 2018.

The results, published on Wednesday, were startling. Microplastic particles in the river had increased more than 40 fold from the storm.

Particles of plastic found in rivers. They may be tiny, but they’re devastating to wildlife in waterways.
Author provided

To inner west Sydneysiders, the Cooks River is known to be particularly polluted. But it’s largely similar to many urban catchments around the world.

If the relationship between storm events and microplastic I found in the Cooks River holds for other urban rivers, then the concentrations of microplastics we’re exposing aquatic animals to is far higher than previously thought.

14 million plastic particles

They may be tiny, but microplastics are a major concern for aquatic life and food webs. Animals such as small fish and zooplankton directly consume the particles, and ingesting microplastics has the potential to slow growth, interfere with reproduction, and cause death.

Determining exactly how much microplastic enters rivers during storms required the rather unglamorous task of standing in the rain to collect water samples, while watching streams of unwanted debris float by (highlights included a fire extinguisher, a two-piece suit, and a litany of tennis balls).

Back in the laboratory, a multi-stage process is used to separate microplastics. This includes floating, filtering, and using strong chemical solutions to dissolve non-plastic items, before identification and counting with specialised microscopes.

Litter caught in a trap in Cooks River. These traps aren’t effective at catching microplastic.
Author provided

In the days before the October 2018 storm, there were 0.4 particles of microplastic per litre of water in the Cooks River. That jumped to 17.4 microplastics per litre after the storm.

Overall, that number averages to a total of 13.8 million microplastic particles floating around in the Cooks River estuary in the days after the storm.




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In other urban waterways around the world scientists have found similarly high numbers of microplastic.

For example in China’s Pearl River, microplastic averages 19.9 particles per litre. In the Mississippi River in the US, microplastic ranges from 28 to 60 particles per litre.

Where do microplastics come from?

We know runoff during storms is one of the main ways pollutants such as sediments and heavy metals end up in waterways. But not much is known about how microplastic gets there.

However think about your street. Wherever you see litter, there are also probably microplastics you cannot see that will eventually work their way into waterways when it rains.




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Many other sources of microplastics are less obvious. Car tyres, for example, which typically contain more plastic than rubber, are a major source of microplastics in our waterways. When your tyres lose tread over time, microscopic tyre fragments are left on roads.

Did you know your car tyres can be a major source of microplastic pollution?
Shutterstock

Microplastics may even build up on roads and rooftops from atmospheric deposition. Everyday, lightweight microplastics such as microfibres from synthetic clothing are carried in the wind, settling and accumulating before they’re washed into rivers and streams.

What’s more, during storms wastewater systems may overflow, contaminating waterways. Along with sewage, this can include high concentrations of synthetic microfibers from household washing machines.

And in regional areas, microplastics may be washing in from agricultural soils. Sewage sludge is often applied to soils as it is rich in nutrients, but the same sludge is also rich in microplastics.

What can be done?

There are many ways to mitigate the negative effects of stormwater on waterways.

Screens, traps, and booms can be fitted to outlets and rivers and catch large pieces of litter such as bottles and packaging. But how useful these approaches are for microplastics is unknown.

Raingardens and retention ponds are used to catch and slow stormwater down, allowing pollutants to drop to bottom rather than being transported into rivers. Artificial wetlands work in similar ways, diverting stormwater to allow natural processes to remove toxins from the water.

Almost 14 million plastic particles were floating in Cooks River after a storm two years ago.
Shutterstock

But while mitigating the effects of stormwater carrying microplastics is important, the only way we’ll truly stop this pollution is to reduce our reliance on plastic. We must develop policies to reduce and regulate how much plastic material is produced and sold.

Plastic is ubiquitous, and its production around the world hasn’t slowed, reaching 359 million tonnes each year. Many countries now have or plan to introduce laws regulating the sale or production of some items such as plastic bags, single-use plastics and microbeads in cleaning products.




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In Australia, most state governments have committed to banning plastic bags, but there are still no laws banning the use of microplastics in cleaning or cosmetic products, or single-use plastics.

We’ve made a good start, but we’ll need deeper changes to what we produce and consume to stem the tide of microplastics in our waterways.The Conversation

James Hitchcock, Post-Doctoral Research Fellow, University of Canberra

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Seafloor currents sweep microplastics into deep-sea hotspots of ocean life



A rockfish hides in a red tree coral in the deep sea.
Geofflos

Ian Kane, University of Manchester and Michael Clare, National Oceanography Centre

What if the “great ocean garbage patches” were just the tip of the iceberg? While more than ten million tonnes of plastic waste enters the sea each year, we actually see just 1% of it – the portion that floats on the ocean surface. What happens to the missing 99% has been unclear for a while.

Plastic debris is gradually broken down into smaller and smaller fragments in the ocean, until it forms particles smaller than 5mm, known as microplastics. Our new research shows that powerful currents sweep these microplastics along the seafloor into large “drifts”, which concentrate them in astounding quantities. We found up to 1.9 million pieces of microplastic in a 5cm-thick layer covering just one square metre – the highest levels of microplastics yet recorded on the ocean floor.

While microplastics have been found on the seafloor worldwide, scientists weren’t sure how they got there and how they spread. We thought that microplastics would separate out according to how big or dense they were, in a similar manner to natural sediment. But plastics are different – some float, but more than half of them sink.




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Plastics which once floated can sink as they become coated in algae, or if bound up with other sticky minerals and organic matter. Recent research has shown that rivers transport microplastics to the ocean too, and laboratory experiments revealed that giant underwater avalanches of sediment can transport these tiny particles along deep-sea canyons to greater depths.

We’ve now discovered how a global network of deep-sea currents transports microplastics, creating plastic hotspots within vast sediment drifts. By catching a ride on these currents, microplastics may be accumulating where deep-sea life is abundant.

Once plastic debris has broken down and sinks to the ocean floor, currents sweep the particles into vast drifts.
Ian Kane, Author provided

From bedroom floors to the seafloor

We surveyed an area of the Mediterranean off the western coast of Italy, known as the Tyrrhenian Sea, and studied the bottom currents that flow near the seafloor. These currents are driven by differences in water salinity and temperature as part of a system of ocean circulation that spans the globe. Seafloor drifts of sediment can be many kilometres across and hundreds of metres high, forming where these currents lose their strength.

We analysed sediment samples from the seafloor taken at depths of several hundred metres. To avoid disturbing the surface layer of sediment, we used samples taken with box-cores, which are like big cookie cutters. In the laboratory, we separated microplastics from the sediment and counted them under microscopes, analysing them using infra-red spectroscopy to find out what kinds of plastic polymer types were there.

A microplastic fibre seen under a microscope.
Ian Kane, Author provided

Most microplastics found on the seafloor are fibres from clothes and textiles. These are particularly insidious, as they can be eaten and absorbed by organisms. Although microplastics on their own are often non-toxic, studies show the build-up of toxins on their surfaces can harm organisms if ingested.

These deep ocean currents also carry oxygenated water and nutrients, meaning that the seafloor hotspots where microplastics accumulate may also be home to important ecosystems such as deep-sea coral reefs that have evolved to depend on these flows, but are now receiving huge quantities of microplastics instead.

What was once a hidden problem has now been uncovered – natural currents and the flow of plastic waste into the ocean are turning parts of the seafloor into repositories for microplastics. The cheap plastic goods we take for granted eventually end up somewhere. The clothes that may only last weeks in your wardrobe linger for decades to centuries on the seafloor, potentially harming the unique and poorly understood creatures that live there.The Conversation

Ian Kane, Reader in Geology, University of Manchester and Michael Clare, Principal Researcher in Marine Geoscience, National Oceanography Centre

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Using lots of plastic packaging during the coronavirus crisis? You’re not alone


Daiane Scaraboto, University of Melbourne; Alison M Joubert, The University of Queensland, and Claudia Gonzalez-Arcos, The University of Queensland

In eight years, US environmentalist and social media star Lauren Singer had never sent an item of rubbish to landfill. But last month, in an impassioned post to her 383,000 Instagram followers, she admitted the reality of COVID-19 has changed that.

I sacrificed my values and bought items in plastic. Lots of it, and plastic that I know isn’t recyclable in NYC (New York City) recycling or maybe even anywhere … why would I go against something that I have actively prioritised and promoted?

Singer wrote that as the seriousness of COVID-19 dawned, she stocked up on items she’d need if confined to her home for a long period – much of it packaged in plastic.

Her confession encapsulates how the pandemic has challenged those of us who are trying to reduce our waste. Many sustainability-conscious people may now find themselves with cupboards stocked with plastic bottles of hand sanitiser, disposable wipes and takeaway food containers.

So let’s look at why this is happening, and what to do about it.

Sustainability out the window

We research how consumers respond to change, such as why consumers largely resisted single-use plastic bag bans. Recently we’ve explored how the coronavirus has changed the use of plastic bags, containers and other disposable products.

Amid understandable concern over health and hygiene during the pandemic, the problem of disposable plastics has taken a back seat.

For example, Coles’ home delivery service is delivering items in plastic bags (albeit reusable ones) and many coffee shops have banned reusable mugs, including global Starbucks branches.




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Restaurants and other food businesses can now only offer home delivery or takeaway options. Many won’t allow customers to bring their own containers, defaulting to disposables which generate plastic waste. This means many consumers can’t reduce their plastic waste, even if they wanted to.

Demand for products such as disposable wipes, cleaning agents, hand sanitiser, disposable gloves and masks is at a record high. Unfortunately, they’re also being thrown out in unprecedented volumes.

And the imperative to prevent the spread of coronavirus means tonnes of medical waste is being generated. For example, hospitals and aged care facilities have been advised to double-bag clinical waste from COVID-19 patients. While this is a necessary measure, it adds to the plastic waste problem.

Many cafes will not accept reusable cups during the health crisis.
The Conversation

Cause for hope

Sustainability and recycling efforts are continuing. Soft plastics recycler Red Cycle is still operating. However many dropoff points for soft plastics, such as schools and council buildings, are closed, and some supermarkets have removed their dropoff bins.

Boomerang Alliance’s Plastic Free Places program has launched a guide for cafes and restaurants during COVID-19. It shows how to avoid single-use plastics, and what compostable packaging alternatives are available.

As the guide notes, “next year the coronavirus will hopefully be a thing of the past but plastic pollution won’t be. It’s important that we don’t increase plastic waste and litter in the meantime.”

Old habits die hard

In the US, lobbyists for the plastic industry have taken advantage of health fears by arguing single-use plastic bags are a more hygienic option than reusable ones. Plastic bag bans have since been rolled back in the US and elsewhere.

However, there is little evidence to show plastic bags are a safer option, and at least reusable cloth bags can be washed.

A relaxation on plastic bag bans – even if temporary – is likely to have long-term consequences for consumer behaviour. Research shows one of the biggest challenges in promoting sustainable behaviours is to break old habits and adopt new ones. Once people return to using plastic bags, the practice becomes normalised again.

In Europe, the plastic industry is using the threat of coronavirus contamination to push back against a ban on single-use plastics such as food containers and cutlery.

Such reframing of plastic as a “protective” health material can divert attention from its dangers to the environment. Prior research, as well as our preliminary findings, suggest these meanings matter when it comes to encouraging environmentally friendly behaviours.




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Many people are using their time at home to clear out items they no longer need. However, most second-hand and charity shops are closed, so items that might have had a second life end up in landfill.

Similarly, many tool, book and toy libraries are closed, meaning some people will be buying items they might otherwise have borrowed.

Once consumers go back to using plastic bags, it will take time to break the habit again.
Darren England/AAP

What to do

We can expect the environmental cause will return to the foreground when the COVID-19 crisis has passed. In the meantime, reuse what you have, and try to store rather than throw out items for donation or recycling.

Talk to takeaway food outlets about options for using your own containers, and refuse disposable cutlery or napkins with deliveries. Use the time to upskill your coffee-making at home rather than buying it in a takeaway cup. And look for grocery suppliers offering more sustainable delivery packaging, such as cardboard boxes or biodegradable bags.

Above all, be vigilant about ways environmental protections such as plastic bag bans might be undermined during the pandemic, and voice your concerns to politicians.




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The Conversation


Daiane Scaraboto, Associate Professor of Marketing, University of Melbourne; Alison M Joubert, Lecturer in Marketing, The University of Queensland, and Claudia Gonzalez-Arcos, Lecturer in Marketing, The University of Queensland

This article is republished from The Conversation under a Creative Commons license. Read the original article.

For decades, scientists puzzled over the plastic ‘missing’ from our oceans – but now it’s been found


Britta Denise Hardesty, CSIRO and Chris Wilcox, CSIRO

You’ve probably heard that our oceans have become a plastic soup. But in fact, of all the plastic that enters Earth’s oceans each year, just 1% has been observed floating on the surface. So where is the rest of it?

This “missing” plastic has been a longstanding scientific question. To date, the search has focused on oceanic gyres such as the Great Pacific Garbage Patch, the water column (the part of the ocean between the surface and the sea bed), the bottom of the ocean, and the stomachs of marine wildlife.

But our new research suggests ocean plastic is being transported back onshore and pushed permanently onto land away from the water’s edge, where it often becomes trapped in vegetation.

Of course, plastic has been reported on beaches around the world for decades. But there has been little focus on why and how coastal environments are a sink for marine debris. Our findings have big implications for how we tackle ocean plastic.

New research shows a significant amount of plastic pollution from our oceans ends up back on land, where it gets trapped.

The hunt for marine pollution

Our separate, yet-to-be-published research has found around 90% of marine debris that enters the ocean remains in the “littoral zone” (the area of ocean within 8km of the coast). This new study set out to discover what happens to it.

We collected data on the amount and location of plastic pollution every 100 kilometres around the entire coast of Australia between 2011 and 2016. Debris was recorded at 188 locations along the Australian coastline. Of this, 56% was plastic, followed by glass (17%) and foam (10%).

Data was recorded approximately every 100 kilometres along the coast of Australia. Of the marine debris recorded, more than half was plastic.

The debris was a mix of litter from people and deposition from the ocean. The highest concentrations of plastic pollution were found along coastal backshores – areas towards the inland edge of the beach, where the vegetation begins. The further back from the water’s edge we went, the more debris we found.

The amount of marine debris, and where it ends up, is influenced by onshore wave activity and, to a lesser extent, wind activity. Densely populated areas and those where the coast was easily accessible were hotspots for trapped plastics.




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Think about what you see on your beach. Smaller debris is often found near the water’s edge, while larger items such as drink bottles, plastic bags and crisp packets are often found further back from the water, often trapped in vegetation.

We also found more debris near urban areas where rivers and creeks enter the ocean. It could be that our trash is being trapped by waterways before it gets to the sea. We’re finding similar patterns in other countries we’re surveying around the Asia Pacific and beyond.

This pollution kills and maims wildlife when they mistake it for food or get tangled in it. It can damage fragile marine ecosystems by smothering sensitive reefs and transporting invasive species and is potentially a threat to human health if toxins in plastics make their way through the food chain to humans.

It can also become an eyesore, damaging the economy of an area through reduced tourism revenue.

Onshore waves, wind and areas with denser human populations influences where and how much marine debris there is along our coastlines.
CSIRO

Talking rubbish

Our findings highlight the importance of studying the entire width of coastal areas to better understand how much, and where, debris gets trapped, to inform targeted approaches to managing all this waste.

Plastic pollution can be reduced through local changes such as water refill stations, rubbish bins, incentives and awareness campaigns. It can also be reduced through targeted waste management policies to reduce, reuse and recycle plastics. We found container deposit schemes to be a particularly effective incentive in reducing marine pollution.




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This discussion is particularly timely. The National Plastics Summit in Canberra last week brought together governments, industry and non-government organisations to identify new solutions to the plastic waste challenge, and discuss how to meet targets under the National Waste Policy Action Plan. Understanding that so much of our debris remains local, and trapped on land, provides real opportunities for successful management of our waste close to the source. This is particularly critical given the waste export ban starting July 1 at the latest.

Plastic in our oceans is increasing. It’s clear from our research that waste management strategies on land must accommodate much larger volumes of pollution than previously estimated. But the best way to keep plastic from our ocean and land is to stop putting it in.

Arianna Olivelli contributed to this article, and the research upon which it was based.




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The Conversation


Britta Denise Hardesty, Principal Research Scientist, Oceans and Atmosphere Flagship, CSIRO and Chris Wilcox, Senior Research Scientist, CSIRO

This article is republished from The Conversation under a Creative Commons license. Read the original article.