Marine Litter Vital Graphics

9 / 60

9 Marine Litter Vital Graphics
In addition to polymers, additives such as flame retardants
(e.g. polybrominated diphenyl ethers), and plasticisers
(e.g. phthalates) are also mixed into synthetic materials
to increase their flexibility, transparency, durability, and
longevity. Some of these substances, present in most
plastic objects found in the marine environment, are
known to be toxic to marine organisms and to humans
(Rochman et al., 2015).
The plastic used in the manufacture of an object depends
on its intended use. The type of plastic will determine the
ease with which an object can be recycled. Some plastics
cannot be recycled, which means they enter the waste
management system. If they make it into the marine
environment, plastics that are less dense than sea water
will float at the surface. Floating objects can be readily
transported by wind, waves and surface currents and
become widely dispersed across the ocean. Plastics that are
denser than seawaterwill sink to the sea floor and accumulate
or be redistributed, along with other sedimentary particles,
through bottom sedimentary processes.
Marine litter comes in all sizes. Large objects may be tens
of metres in length, such as pieces of wrecked vessels, lost
fishing nets and lost cargo containers. Moderate sized
objects less than one metre long might include plastic
bags, soda bottles or milk containers. Small spheres of
expanded polystyrene are on the scale of millimetres.
Micrometre-sized plastic beads are present in cosmetic
products and synthetic cloth fibres or are derived from
fragments broken down from larger plastic items.
There has recently been a noticeable increase in concern
about the implications of pollution by small sized debris,
especially wheremade up of plastic. The term“microplastic”
has been introduced to describe small plastic debris
commonly less than 5 mm in diameter. The concern about
microplastic pollution is due to its ubiquitous presence
in the marine environment. Yet it is difficult to assess its
quantity because of the small size of the particles and
the fact that little is known about the chemical reactions
and the extent of its incorporation into the trophic
chain. Investigations are also being conducted into the
implications of organisms’ exposure to and intake of plastic
nanoparticles, particles smaller than 1 micron. With such
limited knowledge of the ultimate ecological effects of
microplastics and nanoplastics, there are concerns over
their potential impacts at the level of ecosystems.
DEFINITIONS