Scientists have calculated that around 90% of the plastic waste found in the world’s oceans only gets there via ten rivers alone. Eight of them are in Asia, the remaining two are in Africa. However, river pollution is a global problem: plastic items and particles enter rivers via wastewater, are disposed of in landfills or are simply thrown away by people. They all pass through densely populated areas that lack efficient waste collection, meaning waste often ends up in the river.

Rivers act as a kind of conveyor belt for transporting plastic into the sea. However, it is still unclear how much waste is retained in rivers, for how long and in what form. This depends on both the plastic (its density and particle size) and the river itself (how deep it is, how fast it flows, whether there are dams or other barriers that can hold it back). Two other studies estimate that between 1.15 and 4.38 million tons of plastic enter the sea via rivers from land to sea each year.

Why is plastic pollution bad?

Humans produces huge amounts of plastic – in 2015 it was 400 million tons per year and by 2025 production will double. Scientists estimate that 8 million tons of plastic waste ends up in the ocean every year. However, the study authors caution that this amount may only represent 1% of the actual annual number of pollutants.

Biologists have already shown that the microscopic particles that plastic breaks down into harm marine life – many animals and plants mistake them for food and then die or suffer from various diseases. In a recent British study, microplastics were found in every marine mammal examined. In 2017, it turned out that plastic particles can be found in tap water all over the world – they are subsequently consumed by residents of Europe, Japan and other countries.

The risk to human health from consuming microplastics has not yet been sufficiently studied – scientists cannot say with certainty whether it is harmful or perceived neutrally by the body. In addition, each person consumes an average of around 5g of microplastics per week. The long-term consequences must of course be questioned.

Researchers are now trying to find out what effects microplastics have on the human intestine. However, it is known that large particles are excreted from the body, but the fate of smaller ones remains unknown. In addition to the particles themselves, plastic contains material whose chemicals are harmful to health. Moreover, bacteria and viruses get inside a human’s body.

In a recent study, scientists in Singapore found more than 400 species of bacteria on 275 pieces of microplastic collected from local beaches. These include organisms that cause gastroenteritis and wound infections in humans and are also associated with coral bleaching.

While the impact of plastic consumption is uncertain, the World Health Organization (WHO) calls for reducing plastic consumption and effectively recycling plastic waste, as well as cleaning up rivers and canals through which plastic enters the seas and oceans and spreads around the world.

That is why the members of the “Connected Hearts” association are committed to raising resources to effectively counteract the pollution of the world’s rivers and seas.