Marine litter is defined as any persistent, manufactured or processed solid material discarded, disposed or abandoned in the marine and coastal environment.

It consists of items that have been made or used by people and deliberately discarded into the sea or stream/rivers or on beaches; brought indirectly to the sea with rivers, sewage, stormwater or winds; accidentally lost, including material lost at sea in bad weather (fishing gear, cargo); or deliberately left by people on beaches and shores.

The annual amount of sea debris in the World is estimated to be 6 million tons. The presence of marine debris presents a hazard to shipping and is esthetically detrimental, thus generating negative socio-economic consequences.

The Turkish Black Sea coast is 1695 km long, extending from the Bulgarian border in the west to the Georgia border in the east. Assessments of stream and beach litter show that a large amount of debris (plastics, wood pieces, metals, glass, clothes, paper etc.) has been observed in different areas of the southern Black Sea coasts. From these, plastics and synthetic materials are the most common types.

In Türkiye, the partners of the project Protecting streams for a clean Black Sea by reducing sediment and litter pollution with joint innovative monitoring and control tools and nature-based practices assessed the different types of litter in the sub-watershed of the Arhavi River Basin and installed litter trap to mitigate litter stream pollution.