George George Idowu
Millions of tons of plastic waste are being dumped into the world’s waterways every year, threatening aquatic life and ecosystems. Whether in the form of bottles, tires, packaging, or piping, much of this waste ends up in rivers, lakes, and oceans. If current trends continue, the volume of plastic waste could almost double by 2060, according to the Organization for Economic Cooperation and Development (OECD).
Since the 1950s, mass production of plastic has skyrocketed, leading to the accumulation of 140 million tons of plastic waste in the world’s waterways by 2019, according to the OECD’s 2023 report. Of this, 78% is found in freshwater ecosystems like rivers and lakes, while 22% forms the “plastic soup” floating in the world’s oceans.
This pollution stems from poor waste management practices, such as burning plastic in open pits or dumping it in unauthorized sites. Large portions of this plastic waste, particularly items like bottles and construction materials, sink to the bottom of waterways and lakes. Other waste, such as food packaging and closed plastic bottles, floats on the surface for years or even decades before eventually drifting into the oceans.
In addition to land-based pollution, ocean-bound plastic waste also comes from shipping activities, including discarded fishing nets and other gear.
Furthermore, large plastic waste (macroplastics) breaks down slowly, over a period ranging from six months to 35 years. As these macroplastics degrade, they become microplastics—tiny particles less than five millimeters in size that pose an even greater danger to marine life. These microplastics are more easily ingested by aquatic species, increasing the threat to biodiversity.
The movement of plastic waste from land into waterways and ultimately into the sea is uneven across the globe.
A 2021 study by Ocean Cleanup, published in Science Advances, revealed that out of 100,000 global waterways, just 1,000 are responsible for about 80% of the macroplastic waste in the oceans. The remaining 20% comes from 30,000 smaller rivers.
Most of the major plastic-polluting rivers are located in Asia. Of the 50 main rivers that carry plastic to the ocean, 44 are in Asia, largely due to high population densities and inadequate waste management systems. The Philippines, a country made up of thousands of islands, is the largest contributor to plastic waste to the sea. Its Pasig River, which flows into Manila Bay, is the most plastic-polluted river in the world. Other rivers contributing significantly to ocean pollution include the Philippines’ Tullahan and Meycauayan Rivers, India’s Ulhas River, and Malaysia’s Klang River.
Driven by population growth and increasing consumption, global plastic use is expected to nearly triple between 2019 and 2060.
According to the OECD, plastic consumption could rise to 1,231 million tons per year by 2060, significantly escalating the plastic waste crisis. If no meaningful action is taken, 493 million tons of plastic waste could accumulate in aquatic ecosystems by 2060.
The majority of this waste will likely come from developing regions such as sub-Saharan Africa, China, India, and other Asian countries. These areas face significant challenges in improving waste management, which could lead to an exponential increase in the volume of plastic entering rivers and oceans.
However, there is some hope in developed regions like Europe and the United States. Thanks to better waste management practices, these regions are expected to reduce the amount of plastic waste entering aquatic environments.
Yet, this improvement is not sufficient to counteract the rising levels of plastic pollution in other parts of the world.
The plastic waste crisis poses an urgent and growing threat to aquatic ecosystems and the species that depend on them.
As plastic continues to build up in the world’s rivers, lakes, and oceans, it will have increasingly severe consequences for marine life and human populations that rely on these waters.
To combat this crisis, strong global measures are necessary.
Improving waste management practices, promoting recycling, reducing plastic production, and finding alternatives to single-use plastics are all critical steps that need to be taken. Without swift action, the future of the planet’s waterways—and the biodiversity they support – will be at grave risk.
