Every year, millions of tonnes of waste end up in seas all over the world. It is only recently that people are becoming aware of how this phenomenon of marine litter represents an economic, environmental and human health problem. Various actions have been put in place to study and seek a solution to marine litter, but it represents a complex and multifaceted challenge.

What is marine litter?

Marine litter consists of the dispersal into the sea of objects made and used daily by man and then discarded or lost along the coastline or in the sea. This includes materials that, having been discarded on land, reach the sea through rivers, wind, run-off and municipal waste (ISPRA marine strategy). 

This phenomenon is caused by poor solid waste management and wastewater treatment practices (including water from meteorological phenomena), lack of infrastructure and people's lack of awareness of the consequences their actions may have.  

Although we have known about marine litter for years, it only started to be considered a real problem in 2010, before reaching the current levels of knowledge and awareness.

Various actions have been put in place to study and assess the phenomenon, understand its global impact and seek solutions. However, cleaning up the seas is not the only way to combat marine litter: prevention policies must be adopted globally. Government contributions are important, but individual awareness of the problem is also indispensable.

The scale of marine litter

Approximately 75% of global marine litter is made up of plastic (openpolis data), a material which, due to its characteristics, including the fact that it remains in the environment for many years and its ability to break down into microscopic particles, creates various environmental problems.

It is estimated that more than 150 million tonnes of plastic are accumulated in the world's oceans, with 4.6 to 12.7 million tonnes being added each year (according to Jambeck et al).

Recent studies have shown that the annual flow of plastic waste into the ocean could almost triple by 2040 to 29 million tonnes per year, equivalent to 50 kg of plastic for every metre of coastline worldwide (data source: Marine litter - GES - Environment – European Commission (europa.eu).

Sources of marine litter

According to some estimates, about 80% of the debris found in the marine environment comes from land-based activities. The source of marine litter is not necessarily limited to human activities along the coast. Even if disposed of on land, rivers, floods and wind transport waste to the sea.

Fishing, shipping, off-shore facilities such as oil rigs and the sewage system contribute towards the rest.

According to a more in-depth analysis, the main sources of marine litter are as follows:

Land-based activities:

  • landfills and littering of beaches and coastal areas (tourism)
  • rivers and floodwaters
  • industrial emissions
  • discharge from storm water drains
  • untreated municipal sewerage


Sea-based activities:

  • fishing and aquaculture
  • illegal or accidental dumping at sea from shipping (e.g. transport, tourism)
  • offshore mining and extraction

Environmental impact

This phenomenon has numerous consequences for life on the planet, mainly ecological but also economic and social:

  1. ecological impact - with lethal or sub-lethal effects on plants and animals through being entrapped, physical damage and ingestion, accumulation of chemicals through plastics and easier dispersion of alien species through transport, loss of biodiversity and ecosystem functions and services. For example, discarded, lost or abandoned fishing gear continues to trap animals, suffocating their habitats and posing a danger to navigation.
  2. economic impact - reduction of tourism, mechanical damage to vessels and fishing equipment, reduction in the fishing catch and clean-up costs to recover and dispose of waste dispersed at sea.
  3. social impact - reduction of the aesthetic value and public use of the environment.

Particular attention is being paid to microplastics, which are difficult to intercept, but which can easily find their way into the food chain and are often a vehicle for the spread of certain toxic chemicals. Toxins such as DDT, BPA and pesticides stick to these tiny plastic particles, which can be accidentally ingested by small aquatic life. 

Once ingested, these toxins biomagnify as they move up the food chain, accumulating in birds, marine life and possibly humans.

Actions to combat and prevent the phenomenon

Various proposals have been put forward to combat and prevent marine litter: in particular, action must be taken on land, before waste reaches the sea. To this end, the EU has policies and legislation in place to improve waste management, reduce packaging waste and increase recycling rates (of plastics in particular), improve waste water treatment and generally use resources more efficiently.

Directives have also been issued to help reduce pollution caused by ships and ports. Specifically, the Marine Strategy Framework Directive (MSFD) requires EU member states to guarantee that, by 2020, “properties and quantities of marine litter do not cause harm to the coastal and marine environment”.

More recently, within the plastics strategy adopted by the Commission in 2018, most of the measures proposed directly or indirectly concern marine litter, including its international dimension.

Directive on single-use plastics and fishing gear

In the new action plan for the circular economy, the Commission even committed itself to dealing with microplastics released unintentionally, developing labelling, standardisation, certification and regulatory measures.

Directive on port reception facilities for the delivery of waste

Conversely, for waste already dispersed in the sea, the actions undertaken relate to recovery through special campaigns involving both governments and those working at sea (mainly fishermen) as well as citizens through individual collections on beaches.

European projects for the study and prevention of marine litter

Over the last decade, many European projects have been promoted to study the phenomenon of marine litter and how to prevent it, most recently:

  • the mobile app Marine LitterWatch, developed by the European Environment Agency to strengthen Europe's knowledge base and thus support European policy-making
  • the European project COMMON, which in its first year created a network of over 500 stakeholders, including institutions, bodies, associations, municipalities and cooperatives, to foster common governance models in the countries involved: Italy, Lebanon and Tunisia. COMMON will coordinate a permanent network that will unite many of the recovery centres in the three countries involved under the same leadership.


Further readings


Report Mare Plasticum: The Mediterranean Unione Mondiale per la Conservazione della Natura (IUCN)

Marine LitterWatch

Our Oceans, Seas and Coasts (UE)

Marine litter: the issue – UNEP UN Environment Programme