A new study published in Science Advances has found that 1,000 rivers, or 1% of rivers globally, contribute approximately 80% of all riverine plastic that flows into the oceans. According to the researchers behind the study, the magnitude of pollution from a river can be influenced by various factors, with the key factors being water management policies in the region, amount of local rainfall and a region’s proximity to oceans.
The study was conducted by researchers from The Ocean Cleanup, a nonprofit engineering organization with an aim of using technology to reduce ocean pollution. The Ocean Cleanup finds ways of preventing pollution and implements them where possible. In a bid to find a way of reducing riverine plastic, the team set out on a mission to determine pollution distribution based on rivers and regions.
For the past three years, the researchers have collected samples from 67 rivers in 14 countries of 3 continents. The samples provide an insight into the amount of plastic each region supplies and how it is distributed globally. Besides sampling, the team used data and advanced computer modeling to arrive at more accurate results than previous studies on the same topic. Previous studies indicated that only 5 to 47 rivers in the world account for the majority of plastic pollution to the oceans. The Ocean Cleanup’s study has now pushed that number to about 1,000 rivers. Even so, 1,000 rivers is still a small and manageable number, considering that they only represent 1% of global rivers.
The study notes that the cumulative pollution into the ocean mostly depends on the waste management approach by region and not necessarily the quantity of plastic used. A country that uses more plastic may still contribute less plastic pollution to the ocean as long as it has good waste management plans. The study found the Philippines, India, Malaysia, China, and Indonesia to be the largest contributors of riverine plastic.
The researchers now say that this information can be used in determining the areas to target in preventing ocean pollution. However, they say it will take global action to get any significant results.
Image via Alex Hu