Research

Pathways of litter
into the ocean

Plastic litter is now present in large amounts in practically all the oceans. But where does all the litter come from, anyway? And how does it end up in the sea? This infographics shows the pathway of the litter into the world’s oceans and the consequences that litter can have there.

Sandblasting on construction sites

Sandblasting in the immediate vicinity of waterways

Through the use of sandblasting in the immediate vicinity of waterways, large, isolated amounts of micro plastic can make their way into the environment. In 2010 and 2013, approximately 15 tonnes of blasting abrasive were deployed by a German company, but details of the actual amounts are still lacking. In Norway, 650 tonnes of microplastic reaches the sea in this way each year.

Tire abrasion on the road

Wherever plastic surfaces are subjected to mechanical strain, abrasion of synthetic material occurs. As a result, very small plastic particles are released, such as by tire wear on the road. In Norway, 2,250 tonnes of microplastic reaches the sea in this way each year. That is more than half the estimated annual contamination of about 4,000 tons.

Garbage on the beaches

Tourists leave behind garbage on the beaches, which can endanger the health of visitors. Many communities conduct regular beach clean-ups, whereby the coastal states incur costs of several million euros annually. For example, Belgium and the Netherlands spend about 10.4 million euro each year for beach cleaning, and the United Kingdom spends from 18 to 19 million euro. In addition, a loss of profits results when visitors stay away because of garbage pollution. In Korea, polluted beaches led to income losses of up to 29 million euros in 2011. This waste source is best avoided and garbage already present in the sea is best removed.

The outflow of sewage plant contains many micro plastics

The filters of water treatment plants cannot restrain small microplastic particles and fibres. The outflow of a sewage plant can therefore contain more than 1,000 microplastic particles per cubic metre. Sewage sludge containing microplastic is used on the fields as a fertilizer in agriculture.

Often hidden from the human eye: garbage on the sea floor

Large amounts of plastics are embedded in the sea ice

Very large amounts of microplastic particles are embedded in sea ice. As a result, the concentrations in the ice are much higher than in the surrounding seawater. Concentrations of up to 100 microplastic particles per litre have been found in Arctic sea ice. Recent studies of the AWI point to even higher concentrations. When the ice melts, the particles are released into the sea water and the sensitive underlying polar ecosystems. (Graphic: Alfred-Wegener-Institut / Martin Künsting, CC-BY 4.0)

Online Portal for
Marine Litter

Large amounts of litter have accumulated across all parts of our oceans in less than fifty years. Litter has thus become a serious threat to the marine environment, aquatic life and humankind, whose welfare is closely linked with ocean health. Research on marine litter is currently taking a great leap forward and has substantially increased our knowledge of the amount and composition of litter as well as its impacts on the marine environment, aquatic life and people. However, the sheer number of studies scattered all around the globe has rendered this topic increasingly intangible making it difficult for policy makers, public authorities, media and the general public to unearth important information needed to address the urgent questions. LITTERBASE summarises results from 1,926 scientific studies in understandable global maps and figures and opens scientific knowledge on marine litter to the public.

10 questions and answers on marine litter

For many years, the pollution of the oceans caused by plastic waste received little attention from the public. But the littering of the oceans has since become a hot topic, one that concerns many people and receives extensive, frequent media coverage. Although marine plastic, unlike many other pollutants, is visible, many questions remain unanswered from a scientific perspective.

For example, it remains unclear what the overall extent of ocean pollution is, or how the enormous amounts of plastic are impacting marine ecosystems and marine life. The ten questions and answers below, which AWI researchers often encounter, offer a snapshot of the current state of knowledge.