We have no idea how much microplastic is in Australia’s soil (but it could be a lot)



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Microplastic in the soil is extremely difficult to track (or remove).
Florida Sea Grant, CC BY-NC-SA

Alisa Bryce, University of Sydney; Alex McBratney, University of Sydney; Budiman Minasny, University of Sydney; Damien Field, and Stephen Cattle, University of Sydney

Microplastics in the ocean, pieces of plastic less than 5mm in size, have shot to infamy in the last few years. Governments and businesses targeted microbeads in cosmetics, some were banned, and the world felt a little better.

Dealing with microbeads in cosmetics is a positive first step, but the reality is that they are just a drop in the ocean (less than a billionth of the world’s ocean).




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Film review: A Plastic Ocean shows us a world awash with rubbish


Microplastics in soil may be a far greater problem. Norwegian research estimates that in Europe and North America, between 110,000 and 730,000 tonnes of microplastic are transferred to agricultural soils each year.

Here lies the issue: we know almost nothing about microplastics in global soils, and even less in Australian soils. In this article we take a look at what we do know, and some questions we need to answer.

How microplastics get into agricultural soil

Sewage sludge and plastic mulch are the two biggest known contributors of microplastics to agricultural soil. Australia produces about 320,000 dry tonnes of biosolids each year, 55% of which is applied to agricultural land. Biosolids, while controversial, are an excellent source of nutrients for farmland. Of the essential plant nutrients, we can only manufacture nitrogen. The rest we must either mine or recycle.

Sewage treatment plants receive water from households, industry, and stormwater, each adding to the load of plastics. Technical clothing such as sportswear and quick-dry fabrics often contain polyesters and polyamides that break off when clothes are washed. Tyre debris and plastic films wash in with the stormwater. Treatment plants filter microplastics out of the water, retaining them in the sludge that is then trucked away and spread over agricultural land.




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In agriculture, plastic mulch suppresses weeds, keeps the soil warm and damp to assist germination, and improves yield. Over time, these mulches break down, and some fragment into smaller pieces.

Biodegradable bioplastic mulches are designed to break down into carbon dioxide, water, and various “natural substances”. Environmentally friendly plastics are often more expensive, raising the question of whether businesses will be able to afford them.

Other potential sources of plastics in agricultural soil include polymer sealants on fertilisers and pesticides, and industrial compost. Unsold food is often sent to the composting facility still in plastic packaging, and with plastic stickers on every apple and kiwi fruit.

The Australian Standard for composts tacitly recognises that microplastics are likely to be present in these products by having acceptable levels of “visible contamination”. Anyone who has bought compost or garden loam from a landscaping supplier may have noticed pieces of plastic in the mix.

In horticulture, particularly as green walls and green roofs grace more buildings, polystyrenes are used deliberately to make lightweight ‘soil’.

There might be other pathways we don’t know about yet.

What happens once microplastics are in the soil?

Here we stand at the edge of the cavernous knowledge gap, because we don’t know the effect of microplastics in our soil. The overarching question, physically and biologically, is where do microplastics go?

How plastics fragment and degrade in the soil depends on the type of plastic and soil conditions. Compostable, PET, and various degradable plastics will behave differently, having different effects on soil physics and biology.

Fragments could move through soil cracks and pores. Larger soil fauna might disperse fragments vertically and laterally, while agricultural practices such as tillage could push plastics deeper into the soil. Some fragmented plastics can absorb agrochemicals.

Soil microbes can break down some plastics, but what are the byproducts and what are their effects? Newer, biodegradable bioplastics theoretically have limited impact as they break down into inert substances. But how long do they take to break down in different soil and climatic conditions, and what proportion in the soil are non-degradable PET plastics?

Both the main form of carbon in soil and polythene (the most common type of plastic) are carbon-based polymers. Could the two integrate? If they did, would this prevent plastics from moving deeper into the soil, but would it also stop them breaking down?

Could plastics be a hidden source of soil carbon storage?

Bioaccumulation

Bioaccumulation is when something builds up in a food chain.

Research into microplastic accumulation on land is sparse at best. A 2017 study in Mexico found microplastics in chicken gizzards. In the study area, waste management is poor and most plastics were ingested directly from the soil surface as opposed to having bioaccumulated.

Nematodes can take up polystyrene beads suggesting some potential for bioaccumulation, however earthworms have reduced growth rate and increased mortality when they ingest microbeads.

Larger microplastics are unlikely to cross plant cell membranes, but it’s possible that plants can absorb the chemicals formed when plastic degrades. Plants have natural mechanisms to keep contaminants out of their fruiting bodies – pieces of plastic in apples or berries is highly unlikely – but root vegetables and leafy greens are a different story.

Metals can accumulate in leafy greens and the skin of root vegetables – could plastics or their byproducts do the same?

This is before we even get to nanoplastics, which are 1-100 nanometres wide. Can plant roots can absorb nanoplastics, and can they pass through an animal’s gut membrane?

Where to now?

The first step is to quantify how much plastic is currently in the soil, where it is, and how much more to expect. This is more difficult in land than water, as it’s easier to filter plastics out the ocean than to separate them from soil samples. The smaller the plastics are, the harder they’ll be to track and identify – which is why research must start now.

Research needs to address the different types of plastics, including beads and other synthetic fibres. Each is likely to act differently in the soil and terrestrial ecosystems.

Understanding how these plastics react will inform the next obvious questions: at what quantity do they become hazardous to soil, plant and animal life, and how can we mitigate this impact?

The ConversationPlastics in soil represent artefacts of human civilisation. Soils are full of human artefacts; if this was not the case then there would be no field archaeology. However, the effects of microplastic may persist far longer than our own civilisation. We must fill in our knowledge gaps swiftly.

Alisa Bryce, Research Affiliate, University of Sydney; Alex McBratney, Professor of Digital Agriculture & Soil Science; Director, Sydney Institute of Agriculture, University of Sydney; Budiman Minasny, Professor in Soil-Landscape Modelling, University of Sydney; Damien Field, Associate professor, and Stephen Cattle, Associate professor, University of Sydney

This article was originally published on The Conversation. Read the original article.

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Logging burns conceal industrial pollution in the name of ‘community safety’



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High intensity logging burns and the resulting smoke plume near Mount Baw Baw, April 2018
Photo Chris Taylor., Author provided

Chris Taylor, University of Melbourne and David Lindenmayer, Australian National University

Earlier this year, Melbourne and large areas of Central Victoria, experienced days of smoke haze and poor air quality warnings as a result of planned burns. It’s a regular event occurring every autumn.

This smoke has been reported by both government and media outlets as largely the result of planned burns to reduce bushfire risk, along with agricultural burn-offs and increased use of wood heaters.




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But this is only part of the story. A good proportion of the smoke this autumn has actually come from the intensive burning of debris left behind after clearfell logging. This is essentially industrial pollution.

Smoke Haze over Mooroolbark and Melbourne’s eastern suburbs on Tuesday 1 May 2018, shortly after the time when the Poor Air Quality Index reached 901.
Photo: Chris Taylor, Author provided

Industrial clearfell logging vs fuel reduction

To understand why clearfell logging burns are different compared with planned burns to reduce bushfire risk, we need to understand clearfell logging, which involves cutting most or all of the commercially valued trees in one single operation across a designated area (called a “coupe”).

Large volumes of forest biomass are left on the ground following clearfell logging in the Mount Disappointment State Forest with the Melbourne City Skyline in the background, August 2010.
Photo. Chris Taylor., Author provided

In the process of clearfell logging, understorey vegetation is usually pushed over. Along with tree heads and branches left behind after logging, large volumes of debris – known as “slash” – are created. This is partially removed by applying a high intensity burn across the coupe, which in turn establishes an ash seed bed for the next crop of trees to be established. Generally, around 90-100% of the coupe is burnt.

In contrast, planned burns to reduce bushfire risk (otherwise referred to as fuel reduction burns) are less intense. They mostly target “fine fuels” (vegetation less than 6mm in diameter) on the forest floor and in the understorey, which may average around 15 tonnes per hectare (t/ha). Burn coverage is usually 50-70% of the site.

Surface and understorey ‘fine fuels’ targeted in a recent low intensity burn near Mt Dandenong in April 2018.
Photo: Chris Taylor, Author provided

Clearfell logging burns consume much larger volumes of vegetation biomass in the form of tree heads, branches, bark and downed understorey vegetation. According to a report completed for the National Carbon Accounting System, clearfell logging burns consume, on average, 130 t/ha of slash in mixed-species forest and 140 t/ha of slash in Mountain Ash forests. This means that, while clearfell logging burns cover much less ground than fuel reduction burns, they burn far more biomass per hectare – generating far more smoke.

The list of planned burns on Forest Fire Management Victoria’s website showed that, at the beginning of May, 77 of the 119 burns either lit or planned to be lit across the Central Highlands of Victoria and surrounding areas were on logging coupes.




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These burns were individually lit over a period of weeks, with some days predominantly logging burns, others fuel reduction burns. An example when logging burns were prominent occurred on April 20 this year, where 10 out of 12 planned burns were observed as occurring on logging coupes. Using a simple calculation based on average biomass consumption, fuel loads and burn coverage for logging and fuel reduction burns, we estimate that up to 99% of biomass burnt most likely occurred on logging coupes. The following day, the Environmental Protection Authority observed “poor” air quality at multiple air monitoring stations across Melbourne due to smoke.

MODIS Rapid Response Terra Satellite image taken 20 April 2018 showing the smoke intensity of the logging burns.
NASA 2018

Even on days when the majority of burns lit were for fuel reduction, planned logging burns still contributed a proportion of biomass burned. For example, on April 30, only three out of 12 planned burns were observed as occurring on logging coupes, but they may have contributed to around one-third of the total biomass burned.




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Likewise, on the following day, the Environmental Protection Authority observed “very poor” air quality across multiple air monitoring stations. While multiple planned burns contributed to this pollution event, we contend that logging burns increased the levels of pollution in addition to the smoke originating from fuel reduction burns.

MODIS Rapid Response Terra Satellite image taken 30 April 2018 showing the smoke intensity of the planned burns.
NASA 2018

The key issue here is that not all “planned burns” are equivalent. Fuel reduction burns are intended to reduce the bushfire risk to lives and property. Indeed, work led by The Australian National University shows that regular fuel reduction burns can reduce risk to properties if carried out within close proximity.

In contrast, clearfell logging burns are part of an industrial process that extracts pulp logs and sawlogs for commercial sale to private enterprise. They play no part in reducing bushfire risk to life and property. Actually, the reverse is true: logging makes forests more prone to subsequent high-severity crown-consuming fires with associated risks to communities.




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Victoria’s logged landscapes are at increased risk of bushfire


Given that a substantial proportion of the recent smoke over Melbourne and surrounding regional Victoria likely originated from logging burns, could that smoke be deemed industrial pollution? This is a valid question, given the serious health impacts associated with smoke pollution.

The ConversationLogging burns would not be needed (and a substantial amount of associated smoke not generated) if the forest had not been logged in the first place. It is imperative that government departments inform the public about the smoke pollution coming from logging operations, whose purpose is for private commercial gain.

Chris Taylor, Researcher, University of Melbourne and David Lindenmayer, Professor, The Fenner School of Environment and Society, Australian National University

This article was originally published on The Conversation. Read the original article.

Don’t believe the label: ‘flushable wipes’ clog our sewers



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Don’t believe the wipe hype: they can’t be flushed down toilets, not matter what the label says.
SIM Central and South East Asia Follow/Flickr, CC BY-NC

Ian Wright, Western Sydney University

The manufacturer of White King “flushable” wipes has been fined A$700,000 because these are not, in fact, flushable. The wipes, advertised as “just like toilet paper”, cannot disintegrate in the sewerage system, and cause major blockages.

The Federal Court found Pental Products and Pental Limited, which manufacture the wipes, guilty of making false and misleading representations. In particular, Pental claimed that the wipes would break down in the sewerage system, like toilet paper does.




Read more:
Ten ‘stealth microplastics’ to avoid if you want to save the oceans


So-called flushable wipes, now sold for everything from make-up removal to luxury toilet paper, are a growing hazard to public health. Sydney Water says 75% of all sewer blockages in the city’s waste-water system involve wipes.

Don’t trust the label

While wipes might look a bit like toilet paper, there are major differences. Wipes are made from a very tough material called “air-laid paper”, and are often impregnated with cleansing chemicals, disinfectants and cosmetic scents.

Air-laid paper behaves very differently in sewers to toilet paper and does not readily disintegrate in water.

A CHOICE demonstration comparing wipes with toilet paper over 20 hours.

When in sewer pipes the resilient wipes have a tendency to entangle with other wipes and create blockages. This is a bit like the knot of tangled clothing sometimes found in the washing machine. Sewerage system managers around the globe seem powerless to prevent the problem.

Sewer blockages caused by wipes look grotesque. Unpleasant work in confined places is required to remove the blockages (some of which is done by hand!). In 2016 Newcastle’s Hunter Water removed an ugly seven-metre snake of wipes and assorted sewage debris, weighing roughly a tonne, from its sewers.

Wither do you wipe?

Wipes become very popular in the 1990s to help in cleaning babies’ bottoms while changing nappies. Since then, many similar products (“wet wipes”, “baby wipes” and “face wipes”) have proliferated well beyond the baby aisle.

Wipes may be advertised for personal hygiene, removing makeup and cleaning hands. Others are marketed for cleaning bathroom surfaces, toilets and other household areas. The marketing of wipes often boasts how easy they are to dispose by simply flushing them down the toilet.

More recently, a booming adult market is expanding their use as a luxury alternative to toilet paper, buoyed by endorsements from celebrities like Will Smith and Will.i.am. Research by Sydney Water found that males in the 15-44 bracket particularly preferred to use wipes rather than toilet paper. The same market survey estimated that a quarter of Sydney Water’s 4.6 million customers flush wipes down the toilet rather than putting them in a bin.

The three Ps

The fine imposed on Pental Products and Pental Limited for their “flushable” wipes is an important signal to others in this growing market.

However, wipes are not the only waste item that people should not flush down the toilet. This issue gained international notoriety in 2017 when Thames Water in London removed a 130-tonne monster sewer blockage, in a difficult and laborious three-week operation. The blockage was an accumulation of solids called a fatberg – a nightmarish combination of wipes, congealed fat, nappies, female sanitary products, and condoms.




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To fight the fatbergs we have to rethink how we treat sewage waste


Have we forgotten what toilets are for? The Australia Water Association reminds us that they are for the three Ps: pee, poo and paper (toilet paper only).

Perhaps people should visit an Irish website called think before you flush. It lists other common waste objects that should not be flushed, such as cigarette butts, cotton buds, dental floss, hair and unwanted medication. It also advises that a bin be placed in each bathroom.

The ConversationHopefully, packets of wipes will now carry warning labels to advise users not to flush them down the toilet. Just because you can flush something down the toilet does not mean it is good for the environment or society to do so.

Ian Wright, Senior Lecturer in Environmental Science, Western Sydney University

This article was originally published on The Conversation. Read the original article.

Sustainable shopping: take the ‘litter’ out of glitter


Jennifer Lavers, University of Tasmania

Shopping can be confusing at the best of times, and trying to find environmentally friendly options makes it even more difficult. Welcome to our Sustainable Shopping series, in which we ask experts to provide easy eco-friendly guides to purchases big and small. Send us your suggestions for future articles here.


Scientists often get a bad rap as party poopers. As a case in point, my colleagues and I have provided data on the impacts of balloon releases on marine wildlife.

So when glitter – a highly visible and easily obtained microplastic – comes under the microscope, you might be tempted to groan. The good news is that we’re not out to ruin the fun: with Mardi Gras around the corner (bringing a ubiquity of sparkling Instagrams), here’s how to find ecologically friendly glitter.




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All glitter goes to the ocean

When something fun or common is revealed to be destructive it should be a point of pride in our society that we adjust, adapt and move on to safer alternatives.

It therefore makes sense to investigate what data exist for glitter, and to consider whether it’s time for a change in attitude. So, what is glitter?

Glitter is typically made from polyethylene, the same plastic found in plastic bags and a host of other products. Despite glitter’s popularity in everything from cosmetics and toothpaste to crafts and clothes, remarkably little is known about the distribution or impacts of glitter on our environment. As a scientist, that worries me. Glitter is incorporated into consumer products without any real knowledge of its safety.




Read more:
Ten ‘stealth microplastics’ to avoid if you want to save the oceans


In contrast, there are dozens of scientific papers on micro-bead scrubbers (tiny plastic beads), which originate from many of the same products (such as cosmetics and toothpaste).

Research on micro-beads suggests that around 8 trillion beads are released into aquatic habitats every day in the United States alone.

Data for glitter are not available, but given its widespread use the situation is likely to be similarly alarming. It’s far too small for waste treatment facilities to capture, so glitter goes straight into your local river and out into the ocean. Because glitter particles are typically 1 millimetre in size or smaller, they can be ingested by a range of creatures, including mussels.

Again, data on micro-beads can tell us why we should be worried about this: a recent study from Australia showed that toxic chemicals associated with micro-beads can “leach” into the tissues of marine creatures, contaminating their bodies. If mussels, fish and other animals are ingesting glitter and micro-beads, these contaminants likely also pose a risk to humans that consume them.




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Thankfully, science is here to help. A range of compostable, vegan, 100% plastic-free “bio-glitters” have been created and are readily available online. So, at your next event, you can celebrate in glorious, sparkly style while also educating passers-by about ocean conservation. (I assure you, this is very popular; I do it all the time and I’m the life of the party.)

What to look for

Mica, a naturally occurring sparkling mineral, is often offered as a non-plastic alternative to glitter. However, some brands, such as Lush, are now using “synthetic mica” (made in a lab) because mica mining has been associated with child labour, especially in India.

Some plastics labelled “bio-degradable” will only break down in industrial composting units, at temperatures over 50℃. This is very unlikely to happen in the ocean, so look for terms like “compostable” and “organic” instead. (For more information on the difference between bio-degradable, compostable and everything in between, this United Nations report is very comprehensive – just read the summary if you’re in a hurry).

Fortunately, eco-friendly glitter is becoming much easier to find around the world, and more suppliers are turning to cellulose and other plant-derived bases for their product. Wild Glitter‘s founder, like many in the industry, cites “watching a weekend’s worth of plastic glitter wash down the plughole after a festival” as the impetus to sell an “ethical, eco-friendly, cruelty-free way to sparkle”.

Eco Glitter Fun is a member of the Plastics Ocean Foundation, a global non-profit; Glo Tatts makes beautiful temporary glitter tattoos; and, for an Australian twist, Eco Glitter make their product from Eucalyptus cellulose.




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Bio-glitter can be incorporated into any product. Tasmanian soap maker Veronica Foale switched to bio-glitter last year and hasn’t looked back – if a small business in a rural area can do it, you can too!

The ConversationThis is the key to success in the battle against litter: not all changes are difficult and affordable alternatives do exist. Once you’ve mastered bio-glitter, embrace the next challenge – a bamboo toothbrush perhaps, or reusable Onya produce bags? Never stop learning. Go forth and sparkle responsibly.

Jennifer Lavers, Research Scientist, Institute for Marine and Antarctic Studies, University of Tasmania

This article was originally published on The Conversation. Read the original article.

11 billion pieces of plastic bring disease threat to coral reefs



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A plastic bottle trapped on a coral reef.
Tane Sinclair-Taylor, Author provided

Joleah Lamb, Cornell University

There are more than 11 billion pieces of plastic debris on coral reefs across the Asia-Pacific, according to our new research, which also found that contact with plastic can make corals more than 20 times more susceptible to disease.

In our study, published today in Science, we examined more than 124,000 reef-building corals and found that 89% of corals with trapped plastic had visual signs of disease – a marked increase from the 4% chance of a coral having disease without plastic.

Globally, more than 275 million people live within 30km of coral reefs, relying on them for food, coastal protection, tourism income, and cultural value.

With coral reefs already under pressure from climate change and mass bleaching events, our findings reveal another significant threat to the world’s corals and the ecosystems and livelihoods they support.




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In collaboration with numerous experts and underwater surveyors across Indonesia, Myanmar, Thailand and Australia, we collected data from 159 coral reefs between 2010 and 2014. In so doing, we collected one of the most extensive datasets of coral health in this region and plastic waste levels on coral reefs globally.

There is a huge disparity between global estimates of plastic waste entering the oceans and the amount that washes up on beaches or is found floating on the surface.

Our research provides one of the most comprehensive estimates of plastic waste on the seafloor, and its impact on one of the world’s most important ecosystems.

Plastic litter in a fishing village in Myanmar.
Kathryn Berry

The number of plastic items entangled on the reefs varied immensely among the different regions we surveyed – with the lowest levels found in Australia and the highest in Indonesia.

An estimated 80% of marine plastic debris originates from land. The variation of plastic we observed on reefs during our surveys corresponded to the estimated levels of plastic litter entering the ocean from the nearest coast. One-third of the reefs we surveyed had no derelict plastic waste, however others had up 26 pieces of plastic debris per 100 square metres.

We estimate that there are roughly 11.1 billion plastic items on coral reefs across the Asia-Pacific. What’s more, we forecast that this will increase 40% in the next seven years – equating to an estimated 15.7 billion plastic items by 2025.

This increase is set to happen much faster in developing countries than industrialised ones. According to our projections, between 2010 and 2025 the amount of plastic debris on Australian coral reefs will increase by only about 1%, whereas for Myanmar it will almost double.

How can plastic waste cause disease?

Although the mechanisms are not yet clear, the influence of plastic debris on disease development may differ among the three main global diseases we observed to increase when plastic was present.

Plastic debris can open wounds in coral tissues, potentially letting in pathogens such as Halofolliculina corallasia, the microbe that causes skeletal eroding band disease.

Plastic debris could also introduce pathogens directly. Polyvinyl chloride (PVC) – a very common plastic used in children’s toys, building materials like pipes, and many other products – have been found carrying a family of bacteria called Rhodobacterales, which are associated with a suite of coral diseases.

Similarly, polypropylene – which is used to make bottle caps and toothbrushes – can be colonised by Vibrio, a potential pathogen linked to a globally devastating group of coral diseases known as white syndromes.

Finally, plastic debris overtopping corals can block out light and create low-oxygen conditions that favour the growth of microorganisms linked to black band disease.

Plastic debris floating over corals.
Kathryn Berry

Structurally complex corals are eight times more likely to be affected by plastic, particularly branching and tabular species. This has potentially dire implications for the numerous marine species that shelter under or within these corals, and in turn the fisheries that depend on them.




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


Our study shows that reducing the amount of plastic debris entering the ocean can directly prevent disease and death among corals.

The ConversationOnce corals are already infected, it is logistically difficult to treat the resulting diseases. By far the easiest way to tackle the problem is by reducing the amount of mismanaged plastic on land that finds its way into the ocean.

Joleah Lamb, Research fellow, Cornell University

This article was originally published on The Conversation. Read the original article.