As early as the 1970s, microplastics were proven to be a known pollutant in several studies. At that time, large amounts of synthetic fibers and plastic fragments were found in the North Atlantic. It is all the more astonishing that it is still not always clear where these particles come from. For a long time, researchers thought they were fragments of larger plastic objects that had broken off at sea. However, the reality is more complex and the impact of plastic waste on the environment is probably much stronger than assumed at the time.
Rivers – Global Garbage Highways
Recent research shows that rivers are the main transport route for all pollution in our oceans. For example, many European rivers have been shown to be contaminated with microplastics.
In the Delta of the Ebro, one of the largest rivers on the Iberian Peninsula, a study found that the river pumps 2.2 billion pieces of microplastic into the Mediterranean every year – and that is the European average! There are also more extreme cases near densely populated areas, such as the Pearl River Delta near Guangzhou in China. There, researchers reported concentrations between 379 and 7,924 pieces per cubic meter of surface water. For comparison: six years ago, 3 to 108 particles per cubic meter were reported in the French Seine.
The danger lies in ignorance
What is surprising in many studies: main rivers, such as the Rhine or Danube, are often less polluted with microplastics than their smaller tributaries. Contrary to expectations, the concentration in the course of the river remained about the same – even in metropolitan areas and industrial areas.
Many researchers assume that the proportion of plastic particles in the oceans must be much higher than assumed by initial studies. We’re not talking about small differences here. Due to different measurement methods, some studies suspect that there are up to 1 million times more microplastics in the oceans than previously projected.
The latest studies indicate that the abrasion of car tires probably accounts for the largest proportion of microplastics that find their way into rivers via various routes. Another large part could be traced back to textile residues that are detached from textiles during the washing process and get into the waters via sewage treatment plants. In addition to textiles, the fibers can also come from building materials, ropes or fruit nets. Plastic spheres, also known as beads, often come directly from cosmetic residues or building materials.
One thing seems to be emerging more and more: the sediments of rivers contribute significantly more to the microplastic concentration in the oceans than was previously known. And this is where we start.
Seas and coasts: our main patients
When we talk about garbage in the ocean, we mean pretty much all durable, manufactured or processed permanent materials that are released into the marine environment by humans. Including transport routes via rivers, canals, wind and air. Besides rubber, metal, glass, wood or paper, no other material plays such a blatant role as plastics – with a share of over 75% .
As a symptom of today’s throwaway society, plastics can be easily and quickly industrially produced, processed and are often sold cheaply or even free of charge. 4.8 to 12.7 million tons of garbage per year find their way into our oceans. Converted: a truck load per minute!
How can that be?
- Inadequate waste management, e.g. in Southeast Asia and in emerging and developing countries
- Low recycling rates, especially in countries without a landfill ban (also in many European member states)
- high production rates & amp; intensive plastic consumption
- Lack of producer responsibility in different countries
- Lack of environmental education, lack of awareness of the consequences of careless waste disposal
- short life cycle of many products & amp; Longevity of plastic material
Invisible mountains of garbage
It can take centuries for the plastic material to be crushed by physical, chemical and biological processes in the oceans. In addition, wind, waves and currents ensure that garbage can be transported and spread over long distances. Around 30% of this garbage floats on the water surface or is washed up on coasts . That means up to 70% are “in the water” or on the seabed .
In addition to Asia’s coasts and the Mediterranean (also known as “ Plastic Soup “) there are five other zones around the world in which the majority of the mostly already ground plastic waste collects in garbage whirlpools. Two in the Pacific, two in the Atlantic and one in the Indian Ocean. The largest known plastic garbage swirl is the “ Great Pacific Garbage Patch ” (GPGP), which is about 4.5 times the size of Germany.
Biodiversity is threatened
A large part of the litter in our oceans can be traced back to lost or left fishing gear. Even up to 50% within the garbage vortex. For decades, they pose a deadly threat to marine mammals, sea birds and fish. Between 57,000 and 135,000 whales, seals and harbor seals die there every year. Nets often sink to the bottom of the sea, where they are set up as a life-threatening trap.
Packaging materials and ring-like or string-like pieces of rubbish, as well as lines and ropes, harbor a high potential risk for the creatures of our seas. Here we are mainly talking about swallowing or entanglement. Worldwide 817 different marine species are negatively affected by the garbage in some form. Around 17% of these species are on the ICUN Red List or are already classified as threatened or endangered.
A threatening influence
Mostly it is images of strangled marine animals that emotionalize the public. But the food web of many animals is also massively disrupted. Turtles mistake plastic for jellyfish, fish mistake it for krill, seabirds for small fish and whales ingest tons of microplastics as “ false plankton “.
This has sad consequences: suffocation, drowning, injuries to the skin, tissue and muscles, influence on the nervous system, such as limited ability to escape from predators and / or forage. Among other things, animals starve to death as a result of a constant feeling of satiety with a “full” stomach . But also low body fat storage as well as injuries, blockages and inflammation of the gastrointestinal tract are among the effects.
No material is released into our environment even remotely as heavily frequented as plastics. Our oceans and their coasts are hardest hit. But the main route of transport is our rivers. It is particularly problematic that many plastics “survive” in water for decades and threaten the habitats of thousands of living things in and around the water.