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Smaller Urban Rivers Dump Millions of Tons of Plastic into the Oceans

Cleaning plastic debris from riverbank ©Pressmaster/envato
Cleaning plastic debris from riverbank. ©Pressmaster/envato

Much of the debris that collects in the Earth’s oceans begins its journey as plastic waste riding along river currents. Some of it winds up as toxic substances on your dinner plate.

The Great Pacific Garbage Patch, estimated to be twice the size of Texas, is a well-known accumulation of ocean-based plastic. However, how a garbage patch is created or the source of its trash is not so widely spoken of.

The patches occur when gyres—circling ocean currents that pull objects into themselves—build up trash collections stretching from the ocean’s surface to its floor. The debris ranges in size and material, from the nearly invisible microplastics up to sizable items made of varied materials. The main component of that trash? Plastic. An estimated eight million tons end up as ocean debris annually. Much of that is carried by rivers with mouths opening to the ocean, where they dump their loads of trash.

Smaller Rivers Responsible for Ocean Pollution, Study Finds

Scientists formerly believed just ten of the world’s largest rivers carried most of the plastic into the oceans. However, a recent study published in Science Advances asserts this is not the case, that the majority of ocean plastic—80%—comes from more than 1,000 smaller rivers, especially those in urbanized areas located along rivers close to an ocean.

The study also found that the majority of rivers emitting the most plastic tended to have a small total land size, large coastal areas, and high precipitation. The rivers contributing the most plastic are largely concentrated in Asia, particularly in the Philippines, India, Malaysia, China, and Indonesia. The Philippines alone with its nearly 5,000 rivers was found to contribute more than double that of India which produces the second-most tonnage emitted.

The study’s authors suggest that mitigation efforts, those designed to lessen the plastic reaching the oceans, should be concentrated along small to mid-sized rivers to make a significant difference.

Plastic Pollution Kills and Poisons Wildlife, Also Risking Humans

Swan on nest of plastic garbage ©Thue/Wikipedia Commons
Swan on nest of plastic garbage. ©Thue/Wikipedia Commons

Plastic impacts ocean life in many ways. It can trap animals who live on or near the sea, ensnaring them in tangles. It can cause drowning, starvation, or suffocation. Additionally, when plastics break down into small particles, toxic chemicals can bind to them and then be ingested by aquatic wildlife, eventually contaminating the food chain.

Plastic affects corals as well. A report published in the journal Science found that the chance that coral will catch a disease drastically increases when plastic invades the coral. The report's authors believe that corals in the Asian portion of the Pacific Ocean are burdened with more than 11 billion plastic items. That number is projected to increase by 40% by 2025.

Worldwide Efforts Are Reducing the Flow of Trash

According to the World Economic Forum, several effective mitigation strategies are being undertaken on the community and global levels. Active projects include:

  • Ten conveyor belts are located along Kenya’s Athi River and its tributaries. Fencing traps river debris and conveyor belts remove the waste, which is then taken to be recycled.

  • The Ocean Cleanup nonprofit created solar-powered floating collection stations for placement along the world’s most polluted rivers. The Interceptor system picks up trash as the current carries it into the device’s mouth. The plastic is then routed to a conveyor belt that plunks the waste into dumpsters. Three Interceptors are currently being used: one along the Cengkareng Drain in Indonesia, another on the Klang River in Malaysia, and the third on the Rio Ozama in the Dominican Republic.

  • The fundraising campaign #TeamSeas has partnered with two organizations in the quest to rid water bodies of plastic: the Ocean Conservancy for ocean and beach cleanup and The Ocean Cleanup for rivers. So far, they have removed more than 16 million pounds of trash and hold the goal of removing another 14 million by 2025.

  • The TerraCycle Global Foundation has installed booms outfitted with nets to collect debris from a canal off the Chao Phraya, a river in Thailand. In Vietnam's Song Hong River, mesh attached to two floating booms corral river waste that is then fed into a trap on the shore.

  • In Mexico, the international team WILDCOAST has installed a metal screen attached to two booms along a tributary of the Tijuana River to capture plastic waste before it can reach the river.

Global Vision: Commitment to Circular Economies, End of Single-Use Plastics

The United Nations Environment Programme (UNEP) and the Ellen MacArthur Foundation urge world leaders to commit to a circular economy based on the principles of using modern designs to rid the world of waste and pollution; keeping products in use rather than throwing them away; and using nontoxic, biological substances to create consumable products. Single-use plastics are discouraged. Several countries in the European Union have embraced facets of such an economy as well as Australia, Japan, and China. The Global Plastic Action Partnership, an association of government, business, and civil society, also seeks the adoption of a circular economy to answer the plastic pollution problem.

The UNEP instituted the Clean Seas Campaign as another answer to plastic waste. More than sixty nations have pledged to reduce single-use plastics or remove them entirely. Countries signing on plan to accomplish their goal through legislation or regulation, increased investment in recycling plants, and other measures.

The innovative consortium of multinational corporations, NextWave Plastics, sees opportunity in pollution. Touted as the first global network of ocean-bound supply chains, NextWave seeks to rebrand plastic waste as a commodity. Several well-known corporations including Dell Technologies, Trek Bicycles, HP Inc., and IKEA, among others, have begun creating products or packaging from plastic waste otherwise headed for oceans.

Community-Based and Individual Efforts: We Can All Answer the Call

A wide variety of technological solutions are being deployed to rid the planet’s most polluted rivers of waste products, especially plastics. Some efforts are international in scope, while others are community-based or volunteer operations at the local level. The most potent solution would be to stop plastic waste at its source before it reaches the rivers that carry so much waste to the oceans. Communities are uniquely situated to answer the crisis. Because up to 80% of ocean plastic begins in rivers, cleanup there is much easier than when undertaken after it has accumulated in the ocean.

Individuals can help too. If everyone takes responsibility by limiting their reliance on single-use plastic, the rivers, oceans, and living things will all benefit. So do your part: Skip the plastic straws, carry reusable water bottles and grocery bags, join local river or coastal cleanup campaigns, or donate to one of the many organizations engaging in plastic cleanup. And don’t forget the three Rs of pollution control: reduce, reuse, and recycle.


*Cassie Journigan is a writer and editor who lives in the north-central region of Florida in the United States. She focuses on issues related to sustainability. She is passionate about numerous topics including the Earth’s changing climate, pollution, social justice, and cross-cultural communications.


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