So where does all the plastic in our oceans come from? You may be surprised to find out that the majority of plastic waste is washed into the ocean by rivers. And according to a recent study – Fully 90 percent of this polluting waste comes from just 10 rivers.
Eight of the rivers are located in Asia: the Yangtze; Indus; Yellow; Hai He; Ganges; Pearl; Amur; Mekong; and two in Africa – the Nile and the Niger.
“We were able to demonstrate that there is a definite correlation in this respect,” said Dr. Christian Schmidt, one of the authors of the study from the Helmholtz Centre for Environmental Research. “The more waste there is in a catchment area that is not disposed of properly, the more plastic ultimately ends up in the river and takes this route to the sea.”
Christian Schmidt, with the Department of Hydrogeology, Helmholtz-Centre for Environmental Research in Leipzig, Germany, Tobias Krauth, with the Department of Environmental Engineering, University of Applied Sciences Weihenstephan-Triesdorf, in Weidenbach, Germany, and Stephan Wagner, with the Department of Analytical Chemistry, Helmholtz-Centre for Environmental Research in Leipzig, Germany, are the authors of a study published in 2017.
The study, Export of Plastic Debris by Rivers into the Sea, was published in the journal Environmental Science and Technology on October 11, 2017.
Rivers of plastic
The research involved analyzing a global database on plastic debris in the water column across a wide range of river sizes. Schmidt and his team found that the quantity of plastic per cubic meter of water was significantly higher in large rivers than in small ones.
The team determined that the 10 rivers collectively dump anywhere from 0.47 million to 2.75 million metric tons of plastic into the seas every year, with the Yangtze alone dumping up to an estimated 1.5 million metric tons of plastic waste into the Yellow Sea annually.
They found that both microplastics (particles <5 mm) and macroplastics (particles >5 mm) are positively related to the mismanagement of plastic waste (MMPW). Further research also confirmed the rivers had two things in common – high populations living in the surrounding regions, and poor waste management.
The United Nations Environment Assembly followed up on the October study and in December 2017, 194 nations signed a resolution to reduce marine plastic waste.
UN Environment Program head Erik Solheim said “Halving the plastic input from the catchment areas of these rivers would already be a major success, To achieve this, it will be necessary to improve the waste management and raise public awareness for the issue. We hope that our study will make a contribution to a positive development so that the plastic problem in our oceans can be curbed in the long run.”
World Oceans Day
Today, June 8 is World Oceans Day. It has been celebrated unofficially since its original proposal in 1992 by Canada’s International Centre for Ocean Development (ICOD) and the Ocean Institute of Canada (OIC) at the Earth Summit –A UN Conference on Environment and Development (UNCED) in Rio de Janeiro, Brazil.
In carrying through with the Earth Day 2018 theme to end plastic pollution, World Oceans Day is also focused on bringing awareness of what is happening to our planet and its precious ocean waters by our seeming indifference and quite often, poor waste management practices.
So, weep for our oceans and the planet. But while doing so, make the decision to reduce the use of plastics.
