We analysed data from 29,798 clean-ups around the world to uncover some of the worst litter hotspots


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Lauren Roman, CSIRO; Britta Denise Hardesty, CSIRO, and Chris Wilcox, CSIROCoastal litter is a big environmental problem. But how does this litter differ around the world, and why? In the first global analysis of its kind, we set out to answer those questions using data collected by thousands of citizen scientists.

Our analysis, released today, discovered litter hotspots on every inhabited continent, including Australia. This finding busts two persistent myths: that most of the world’s plastic pollution comes from just a few major rivers, and that countries in the Global South are largely to blame for the marine plastic problem.

Single-use plastics formed the majority of litter in this study. And in general, litter hotspots were associated with socioeconomic factors such as a concentration of built infrastructure, less national wealth, and a high level of lighting at night.

Our insights reveal the complex patterns driving coastal pollution, and suggest there is no “one size fits all” solution to cleaning up the world’s oceans. In fact, the best solution is to stop the waste problem long before it reaches the sea.

This study analyses the data collected by hundreds of thousands of citizen scientists conducting clean-ups worldwide.
Copyright PADI AWARE

A complex picture

We are scientists from the CSIRO’s Marine Debris Research team. Our study involved working closely with Ocean Conservancy and the PADI AWARE Foundation, which together hold the world’s most comprehensive litter data sets gathered by citizen scientists.

We analysed hundreds of thousands of items from 22,508 clean-ups on land (at beaches and the edge of rivers and lakes) as well as 7,290 seafloor clean-ups. The clean-ups spanned 116 and 118 countries, respectively, and involved participants recording counts for each item collected.

The analysis showed a huge diversity in the location and scale of plastic pollution hotspots. They were not limited to single countries or rivers – instead, the hotspots occurred in all inhabited continents and across many countries. In many places, litter patterns between neighbouring locations were vastly different.




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Most litter comprised single-use items: cigarette butts, fishing line, food wrappers, and plastic bottles and bags.

In general, places with more overall litter tended to have:

  • more built infrastructure
  • less national wealth
  • bright lighting at night (which indicated urban density).

Cities and other dense urban areas around the world were linked with hotspots of “convenience” single-use plastic items, such as plastic bags, food wrappers, drink bottles, take-away containers, straws, plastic cutlery and lids. These hotspots are represented in the infographic below.



However, not all litter items followed this pattern. For example, cigarette butts followed a regional pattern and were more common in Southern Europe and North Africa.

Fishing line was most abundant in wealthier countries where recreational fishing is a popular pastime. Hotspots included Australia, the United Kingdom and the United States.

Clusters of hotspots were often associated with partially enclosed bays, seas and lakes. These included areas such as the Mediterranean Sea, the Bay of Bengal, the South China and Philippine seas, the Gulf of Mexico, the Caribbean Sea, Lake Malawi and the Great Lakes of North America.

Plastic accumulation in these areas is likely due to factors such as high local littering combined with relatively contained bodies of water.

Plastic bottle hotspots were more common in tropical countries such as Costa Rica and Jamaica, among others. Plastic food wrappers were abundant in the island nations of Southeast Asia, particularly around Indonesia and the Philippines.




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Australia contained several global hotspots for fishing line waste.
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Cleaning up our coasts

Ultimately, our study reveals the diversity and complexity of the plastic pollution issue. We hope it helps governments make waste policy decisions based on sound scientific evidence.

The findings suggest programs to tackle ocean litter should be rolled out at the grassroots level, or within one part of a country, as well as nationally.

In Australia, for example, Zoos Victoria’s Seal The Loop program aims to tackle localised fishing line waste at locations where the pastime is common. The program includes fishing line bins placed on piers and at boat ramps to encourage responsible waste disposal.

And in Malawi and 15 other countries in southern Africa, national bans on plastic bags target this locally problematic item.

Our analysis shows much non-degradable waste found in the environment comes from pre-packaged food and beverages. So regulations specifically addressing this type of packaging can be useful.

In Australia, for example, Hobart is aiming to become the first Australian city to ban single-use plastic takeaway food packaging, as part of an ambitious goal of zero-waste to landfill by 2030.

Other strategies known to change litter behaviour include recycling incentives such as container deposit schemes, particularly in lower socioeconomic areas where littering is highest, as well as education campaigns. And levies on plastic items could also help stop litter entering the environment.

This Saturday September 18, Ocean Conservancy is holding its annual International Coastal Cleanup – come along if you can and if COVID restrictions allow. You’ll be helping your local environment and collecting data to inform tomorrow’s waste management policies.

Land-based clean-ups were conducted across 116 countries. Please join us for the next one.
Rafeed Hussain Ocean Conservancy

The authors would like to acknowledge the tireless volunteers from the International Coastal Cleanup and Dive Against Debris, and collaborators; Ocean Conservancy’s Dr George H. Leonard and Nicholas Mallos, and PADI AWARE Foundation’s Hannah Pragnell-Raasch and Ian Campbell.The Conversation

Lauren Roman, Postdoctoral Researcher, Oceans and Atmosphere, CSIRO; Britta Denise Hardesty, Senior Principal Research Scientist, Oceans and Atmosphere, CSIRO, and Chris Wilcox, Senior Principal Research Scientist, CSIRO

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

From Hobart, to London, to Dhaka: using cameras and AI to build an automatic litter detection system



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Arianna Olivelli, CSIRO and Uwe Rosebrock, CSIRO

It’s estimated about two million tonnes of plastics enter the oceans from rivers each year. But our waterways aren’t just conveyor belts transporting land waste to the oceans: they also capture and retain litter.

Currently, the most common method for monitoring litter relies on humans conducting on-ground visual counts. This process is labour-intensive and makes it difficult to monitor many locations simultaneously or over extended periods.

As part of CSIRO’s research to end plastic waste, we’ve been developing an efficient and scalable environmental monitoring system using artificial intelligence (AI).

The system, which is part of a larger pilot with the City of Hobart, uses AI-based image recognition to track litter in waterways.

Global insights help build a reliable model

The technology is underpinned by two branches of AI: computer vision and deep learning. Computer vision involves training computers to understand and interpret images and videos, whereas deep learning imitates how our brains process data.

Drawing on these capabilities, we worked in partnership with Microsoft (using its Azure cloud computing services) to develop an automated system for monitoring river litter.

We have been detecting and classifying items floating on the surface of Hobart’s stormwater channels, the River Thames in the UK and the Buriganga River in Bangladesh.

We’ve remotely analysed the amount of litter, the type of litter and how this changes across locations.

CSIRO research scientist Chris Wilcox setting up a fixed camera to monitor litter in Hobart.

Major damage from food packaging and bottles

Our work relies heavily on two applications of computer vision. These are “object detection” and “image classification”.

Object detection specifies the location of a particular object in an image and assigns it a label. Image classification assigns one or more labels to the image as a whole.

Before either of these models can be applied reliably, however, they have to be trained, tested and validated using a large number of labelled images. For this, we drew from our footage of river litter collected from Hobart, London and Dhaka.

Our dataset now contains more than 6,100 images with 14,500 individual items. The items are labelled across more than 30 categories including plastic bottles, packaging, beverage cans, paper and plastic cups.

Our data revealed food packaging, beverage bottles and cups were by far the most frequently spotted litter items across all three countries.

Aeriel view of the Buriganga River in Dhaka, Bangladesh.
The Buriganga river flows by Dhaka. It’s one of Bangladesh’s most polluted rivers due to the ongoing dumping of industrial waste (such as from leather tanneries) and human waste.
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Fake images aren’t always harmful

To build a well-performing machine learning model, we needed a balanced set of training images featuring all item categories — even if certain categories are more frequent in real life.

Introducing synthetic (computer generated) images to our dataset was a game changer.

These images were generated by Microsoft’s synthetics team based in Seattle. They rendered various objects and superimposed them over backgrounds obtained from our field photos.

Once the digital objects were created, the superimposition process was automatic. Thus, the team managed to produce thousands of synthetic pictures over just a few weeks, rapidly expanding our training dataset.

In this synthetic image, the transparent cup, face mask and aerosol container are digital renderings superimposed over an original photo taken by one of our cameras.

How are objects identified?

There are a few steps by which our system identifies litter objects in photos. First, the photos are all scored against a single-label (“trash”) object detector. This identifies items of litter in the frame and stores their coordinates as annotations.

These coordinates are then used to isolate the items and score them against an image classifier which includes all the litter categories.

Finally, the model presents the category it thinks the item most likely belongs to, along with a suggested probability for how accurate this guess is.

Here’s an example of the system detecting a water bottle and packaging as trash, and then placing both items into their respective categories. Probabilities are provided for the likely accuracy of the system’s guess regarding an item’s classification.

An AI-driven approach to litter management allows a quicker response than a manual system. But when it comes to litter, the major challenge lies in creating a model that can account for millions of different shapes, colours and sizes.




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We wanted to build a flexible model that could be transferred to new locations and across different river settings, including smaller streams (such as Hobart’s stormwater system) and large urban rivers (such as the River Thames or the Buriganga River).

This way, rather than building new models for each location, we only have to deploy more cameras. Data retrieved could help identify litter hot spots, implement better waste-related policies and improve waste management methods to make them safer, smarter and relatively cheaper.

Keeping an eye on Hobart’s litter

We’ve also been collaborating with the City of Hobart to develop an autonomous sensor network to monitor gross pollutant traps, such as floating barriers or litter socks.

These structures, integrated into Hobart’s stormwater drainage system, are supposed to prevent solid waste such as cans, bottles, tree branches and leaves from reaching the estuary and ocean.

We currently have a network of sensors and six cameras installed under bridges tracking litter in the traps. The system can inform an operator when a trap requires emptying, or other maintenance.

Once in full use, the technology will provide almost real-time monitoring of litter around Hobart — assisting efforts to reduce environmental harm caused by stagnant, and potentially hazardous, waste lost to the environment.




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The Conversation


Arianna Olivelli, Research Affiliate, CSIRO and Uwe Rosebrock, Senior Software Engineer, CSIRO

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

Forget sharks… here’s why you are more likely to be injured by litter at the beach



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Sadly, people plus beach equals litter, so be careful out there.
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Marnie Campbell, Murdoch University; Cameron McMains, Murdoch University; Chad Hewitt, Murdoch University, and Mariana Campos, Murdoch University

Our beaches are our summer playgrounds, yet beach litter and marine debris injures one-fifth of beach users, particularly children and older people.

Our research, published in the journal Science of the Total Environment, found more than 7,800 injuries on New Zealand beaches each year – in 2016, some 595 of them were related to beach litter. The most common injuries caused by litter were punctures and cuts, but they also included fractured limbs, burns, head trauma, and even blindness.

Children under 14 suffered 31% of all beach litter injuries, and were injured by beach litter at twice the rate compared with other locations in New Zealand. Beach litter injury claims exceeded NZ$325,000 in 2016, representing a growing proportion of all beach injury claims. Beach injury claims changed from 1.2% of the total in 2007 to 2.9% in 2016.




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Our study relied on reported injury insurance claims in New Zealand, and thus probably underestimates the true injury rate, particularly for minor wounds. Our 2016 survey of beachgoers in Tasmania found that 21.6% of them had been injured by beach litter at any time previously – even on the island state’s most picturesque beaches.

Alarmingly, most beach users in the Tasmanian survey did not consider beach litter an injury risk, despite the high rate of self-reported injuries.

Awash with danger

As more debris washes ashore and our recreational use of our coasts increases, it is more likely than ever before that we will encounter beach litter, even on remote and “pristine” beaches.

Global studies have found up to 15 items of debris per square metre of beach, even in remote locations. On Henderson Island – a supposedly pristine South Pacific outpost miles from anywhere – some 3,570 new pieces of litter arrive every day on one beach alone.

Beach litter typically includes a huge range of items, such as:

  • broken glass
  • sharp and rusted metal such as car bodies, food cans, fish hooks, and barbed wire
  • flammable or toxic materials such as cigarette lighters, flares, ammunition and explosives, and vessels containing chemicals or rotten food
  • sanitary and medical waste such as used syringes, dirty nappies, condoms, tampons and sanitary pads
  • bagged and unbagged dog faeces and dead domestic animals.

The health hazards posed by beach litter include choking or ingesting poisons (particularly for young children), exposure to toxic chemicals, tripping, punctures and cuts, burns, explosions, and exposure to disease.

Degrading plastic can also produce toxins that contaminate seafood, potentially entering human or ecological food chains.

Rubbish knowledge

Despite the potential severity of these hazards our understanding and study of human health impacts from beach litter is poor. We know more about the impacts of beach litter and marine debris on wildlife than on humans.

Two of our previous studies in Australia and New Zealand have found beach litter that can cause punctures and cuts at densities 227 items per 100 square metres of beach, and choking hazards at densities of 153 items per 100 square metres of beach. These exposures to beach litter hazards in Australia and New Zealand may be 50% higher than global averages (based on preliminary data).




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Even “clean” beaches can be hazardous, and may even increase the likelihood of injury. Visitors to a recently cleaned or supposedly “pristine” beach may be less vigilant for hazards. What’s more, European studies have found that actively cleaned beaches can still have hazardous debris items.

The risk of injury will continue to increase without concerted efforts to prevent addition of new debris and the active removal of existing rubbish. Besides watching where we tread when at the beach and participating in beach cleanups, we also need to make sure we deal with rubbish thoughtfully, so litter doesn’t end up there in the first place.The Conversation

Marnie Campbell, Chevron Harry Butler Chair in Biosecurity and Environmental Science, Murdoch University; Cameron McMains, PhD Candidate, Harry Butler Institute, Murdoch University; Chad Hewitt, Professor and Director, Murdoch Biosecurity Research Centre, Murdoch University, and Mariana Campos, Lecturer and researcher, Murdoch University

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




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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.