Marine Litter

Marine litter is globally acknowledged as a major challenge due to its significant environmental, economic and social implications [1, 2, 3] affecting the health of organisms and ecosystems [4, 5, 6].

With the term marine litter we refer to “any anthropogenic, manufactured, or processed solid material (regardless of size) discarded, disposed of, or abandoned in the environment, including all materials discarded into the sea, on the shore, or brought indirectly to the sea by rivers, sewage, storm water, waves, or winds” [5, 7]. This important environmental issue is included among the eleven descriptors of the Marine Strategy Framework Directive (MSFD - Directive 2008/56/EC) necessary to evaluate the marine environmental conditions.

Marine litter is made by different materials such as wood, glass, or metal. Among marine litter categories, the most abundant are plastics [8, 9, 10]. Plastics production started around the 40s reaching a worldwide production of about 300 million tons in 2016 [11]. The improper plastic handling contributed to the strong environmental impact, especially in the marine environment. Plastic presence in the sea was first described in the early 70s [12]. More recent estimates shows between 4.8 and 12.7 million tonnes of plastic in the ocean and this abundances are expected to increase by about an order of magnitude in 2025 [13].

The harmful fraction of plastic in the ocean are the microplastic, particles smaller than 5 mm that can be directly released in the environment (primary microplastics) or result from the fragmentation processes of larger particles (secondary microplastics) [14, 15, 16].

The presence of microplastics in the oceans is a global issue as these small items interact with a large range of organisms at different trophic levels leading to multiple negative effects [17, 18]. Furthermore, microplastics act as vectors for adsorbed pollutants [19].

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