Plastic from source to sea

Rivers: conveyor belts of plastic pollution

There are 100 rivers worldwide that are 1000 km in length or more. Many of these rivers have names that are known throughout the world, evocative freshwater powerhouses. The Amazon, Mekong, Congo, Yangtze and Ganges are home to millions of people who rely on these waterways for food, transport, income and cultural traditions. 

Whilst these rivers bring enormous advantages and benefits to people and nature, they are also often the dumping ground for waste. One major waste problem is plastic. As plastic is discarded into our waterways, rivers become conveyor belts of plastic debris, transporting this dangerous and toxic cargo into the world's estuaries, deltas and oceans.

Research published in Environmental Science & Technology, shows that rivers collectively dump anywhere from 0.47 million to 2.75 million metric tons of plastic into the oceans every year. Schmidt and his research team found that the quantity of plastic per cubic metre of water was significantly higher in large rivers than in smaller ones.

"Rivers carry trash over long distances and connect nearly all land surfaces with the oceans, making them a major battleground in the fight against sea pollution"~ Christian Schmidt, hydrogeologist at the Helmholtz Center for Environmental Research in Leipzig, Germany

 where does all the plastic come from

The recent Helmholtz study estimates that more than a quarter of all plastic waste into the oceans pours in from just 10 rivers, eight of them in Asia.

The 10 rivers that carry 93 % of all rivers' plastic into our oceans are the Yangtze, Yellow, Hai, Pearl, Amur, Mekong, Indus and Ganges in Asia, and the Niger and Nile in Africa.

These rivers all have two things in common:

1. A large population living in the surrounding region, and 

2. Inadequate waste management processes. 

In addition, public awareness about plastic pollution is often lacking. Garbage gets thrown into the river disappearing out of sight and becomes therefore a "downstream problem".

The Hai River connects two of China's most populous metropolitan areas, Tianjin and Beijing, before flowing into one of the world's busiest shipping lanes, the Bohai Sea. It comes in fourth in the Top Polluters' list. 

The Meghna-Brahmaputra-Ganges is central to India's spiritual life and provides water to more than half a billion people. Sewage, agricultural and industrial waste have made it one of the world's most polluted rivers.

Around 20 million people live in the Mekong Delta, many are dependent on fishing and agriculture for survival. The river flows through six countries, including Vietnam and Laos, and is tenth on the list of river systems that carry most of the 8 million tons of plastic that are dumped into the seas each year.

The Nile and the Niger are the only two African rivers in the Top 10 Polluters. The Nile supports 360 million people who live in the river's basin and tops the list of Africa's biggest polluting rivers. There are several sources of pollution into the Nile, including industrial wastewater discharge, pesticides and chemical fertilizer residue, agricultural water drainage, radioactive discharge, and oil pollution.

In contrast to other trash, plastic can float around for decades. In addition to being harmful to terrestrial and aquatic life, plastics can absorb toxins and break up into microplastics which then enter the food chain.That is our food chain~ 
James Dalton, IUCN Director Global Water Programme
46 percent of plastic floats and can drift for years before eventually concentrating in the ocean gyres (EPA 2006) ©Mr.anaked/Shutterstock

a matter of management 

Plastic pollution is not only a waste challenge, but a production, consumption and handling issue which must be tackled upstream where plastic is produced and consumed.

Eighty percent of pollution to the marine environment comes from land. The growth of plastic production has far outstripped the ability of waste management to keep up. 

In recent years the surge in plastic production has been driven by the demand for  packaging in the growing economies of Asia. In 2010, according to an estimate by Jambeck, half the world's plastic waste was generated by five Asian countries: China, Indonesia, the Philippines, Vietnam, and Sri Lanka. It is also in these countries that garbage collection systems are weak or "nonexistent".

Waste management systems in Asia are currently unable to handle the rapidly growing volume of daily disposed plastic. Changes in consumer behaviour and more integrated approaches to waste management will go a long way towards reducing marine plastic pollution ~ Maeve Nightingale, Asia Regional Coordinator MARPLASTICCS

The most common single-use plastics found in the environment are cigarette butts, plastic drinking bottles, plastic bottle caps, food wrappers, plastic grocery bags, plastic lids, straws and stirrers, other types of plastic bags, and foam take-away containers. These are the waste products of a throwaway culture that treats plastic as a disposable material rather than a valuable resource to be captured, re-used, and re-purposed. 

In the UN Environment report on the state of plastics, 'Single-use Plastics: A roadmap for Sustainability', a global assessment of government action against plastic pollution is laid out. 

"The assessment shows that action can be painless and profitable – with huge gains for people and the planet that help avert the costly downstream costs of pollution. Plastic isn’t the problem. It’s what we do with it.” Erik Solheim, Head of UN Environment

In 2017 IUCN published an overview of legal instruments in European Union Member States on plastic pollution in the marine environment: National Marine Plastic Litter Policies in EU Member States: An Overview

While much plastic enters rivers because of a lack of waste infrastructure, sewage systems contribute too. Wastewater is often an undervalued and neglected resource. If managed well, it can be re-purposed into industrial, agricultural or freshwater processes. Re-using water and treating wastewater represent one of the easiest circular economies. Read more here.

As part of IUCN's newly launched Marine Plastics and Coastal Communities initiative (MARPLASTICCs), funded by the Swedish International Development Agency (Sida), the above video illustrates the different types and life cycle of plastics. 

"Plastic travels vast distances down our rivers and across our oceans. It also persists, outliving us all. Solutions for a circular plastic economy need to consider the full lifecycle of plastic products, consumer choice and behaviour, and the opportunities this brings to change the plastic value chain" Carole Martinez, MARPLASTICCS Project Coordinator

Movements and campaigns to combat the growing problem of plastic pollution are growing. Coalitions such as the Plastic Pollution Coalition and Plastic Oceans are gaining traction. Major news outlets are joining forces to mobilize change. The BBC announced a major new initiative 'Plastics Watch' following the global impact of Blue Planet II by Sir David Attenborough. Community initiatives such as 10 Minutes a Day and The Last Plastic Straw garner a large following and show people care and take action into their own hands. The recent World Cleanup Day saw 13 million people from 144 countries join in the global cleanup. Education material is available online for teachers, for example through Ocean Plastic Education by Ocean Wise. 

Microplastics in the seas now outnumber stars in our galaxy.  From remote islands to the Artic, nowhere is untouched.  If present trends continue, by 2050, our oceans will have more plastic than fish. 
~UN Secretary General António Guterres
Microplastics on a beach © Shutterstock/Loretta Sze



Valuing Plastic, a UNEP-supported report produced by the Plastic Disclosure Project (PDP) and Trucost, makes the business case for managing and disclosing plastic use in the consumer goods industry. It finds that the overall natural capital cost of plastic use in the consumer goods sector each year is US$75 billion. This is the financial cost resulting from impacts such as marine pollution and air pollution caused by incinerating plastic.

"The research unveils the need for companies to consider their plastic footprint, just as they do for carbon, water and forestry," said Andrew Russell, Director of the PDP. "By measuring, managing and reporting plastic use and disposal, companies can mitigate the risks, maximize the opportunities, and become more successful and sustainable."


Humans are already eating plastic from the sea too. The average person who eats seafood swallows up to 11,000 pieces of microplastic every year, according to a study by researchers at the University of Ghent. Most concerning is how little is known about the effects of microplastic consumption on human health (Microplastics and human health—an urgent problem, The Lancet, 2017)

As Prince Charles stated at a recent Our Ocean summit, "plastic is very much on the menu".

In March 2018, the World Health Organisation announced a review into the potential risks of plastic in drinking water after an analysis found 90% of some of the world's most popular bottled water brands contained tiny pieces of plastic. A previous study also found high levels of microplastics in tap water.


Plastic, which is a petroleum product, contributes to global warming. If plastic waste is incinerated, it releases carbon dioxide into the atmosphere, thereby increasing carbon emissions From materials extraction to product production to waste disposal, plastic is connected to climate change at every stage

For example the footprint of a disposable plastic bottle is 82.8 grams of carbon. When you consider we consume 563 billion single use plastic water bottles every year it starts to add up. Every year, production, transportation and consumption of plastic water bottles produces 46 billion tonnes of carbon pollution.


Plastic waste damages the aesthetic value of tourist destinations, leading to decreased tourism-related incomes and major economic costs related to the cleaning and maintenance of the sites

The town of Nice spends roughly € 2 million every year to ensure that beaches remain clean. Many beach destinations however can't afford such costs. In South Korea, a single marine litter event caused a revenue loss of €29m in 2011 compared to 2010, as a result of over 500,000 fewer visitors to the country.

IUCN MARPLASTICCS initiative is based on an four-tiered approach:

In further global efforts to combat plastic pollution, the IUCN Marine and Polar Programme leads the implementation of the Plastimed project (in the Mediterranean region) and Baltic Solutions (see video). These projects aim to assess the scale of pollution, identify further sources of plastic pollution (synthetic textiles, packaging and synthetic rubber), support the investigations into human health implications, review the entry points of ocean pollution, and research the potential detrimental impact of plastic on ice formation in polar regions.

Download PDF: IUCN Issues Brief on Marine Plastics

Plastic in our rivers is a stark reminder of the health of our freshwater systems. It's the visible tip of the iceberg for water quality concerns, and should raise global attention to solving all water quality challenges.~Peter Manyara, IUCN Africa lead MARPLASTICCS

Concern over plastic pollution is mobilizing action and change globally. Improving water quality remains a critical challenge.  For too long we have not managed water as the scarce resource it is - scarce in availability, scarce in access, and scarce in quality. Improving water quality is a governance, investment and social change problem. We have the technological know-how to clean our rivers of plastic, wastewater, and other chemicals and toxins. The time has come to apply this know-how and turn it into concerted action. 

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Photos: Shutterstock • Icons: The Noun Project • Logos: IUCN • Twitter: @IUCN_Water & @MARPLASTICCs • Hashtag: #beatplasticpollution • Editor: Claire Warmenbol, IUCN - International Union for Conservation of Nature