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Marine Litter
Vital Graphics
PATHWAYS
Debris released by
human activity
on land can be
washed by surface runoff or blown by wind into
rivers
and other watercourses
and ultimately be transported
into the ocean. Debris can also be directly dumped or
discharged from boats or sewage plants into rivers
(Rech et al., 2014). Plastic is very efficiently transported
downstream due to its near-neutral buoyancy and may
reach the ocean after only a few days (Kabat et al., 2012).
Rivers transport plastic debris and, because the average
journey is much shorter than the time needed for
plastic to degrade, the majority ultimately reaches the
ocean. Debris can also become stranded on riverbanks
or entangled in vegetation; it may then be remobilized
by wind or surface runoff to continue its journey
downstream (Williams and Simmons, 1997). During high
discharge events caused by heavy rainfall or human-
controlled water releases, plastic and other debris can be
exported far offshore from the river mouth. Dispersal of
debris is also more efficient along coasts that experience
high wave energy and/or large tides or other dynamic
current regimes (Galgani et al., 2000; Carson et al., 2013;
Lechner et al., 2014; Rech et al., 2014).
,, , , . . . ... .
. . . . . . . . . . . . . ... .
. . . . . . . . . . . . . . . . ... .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . .. . Untreated or insu ciently treated water discharged directly into the environment Wastewater outfall discharges Direct discharge At the coastline At sea during sea-based activities Coastal circulation Regional and global circulation Across margin movement Pathways and uxes of plastics into the oceans Rivers, canals and other watercourses through run-o from land Wind Sinking and mid-water oating debris Floating debris Sea oor debris Y Y 99.5 32.9 (Million tonnes) 4.8 (Min) 12.7 Coastal plastic waste Mismanaged plastic waste Plastic waste entering the marine environment i i i i i i i i i i i i i . i >< i >< i >< i >< i >< i i >< . r i . J . . i r j j j i iii
J i J JJJ i i i i i i i i i i i i J i J i J i J ii / /
; Source: Jambeck, J., R., et al., Plastic waste inputs from land into the ocean, Science, 2015; GRID-ArendalAll material that erodes and washes off the land will end up in the marine environment.
This includes solid materials that constitute marine litter. Understanding the role and
importance of the different pathways is crucial to prioritizing efforts to reduce the
amount of debris and microplastics reaching the ocean.
Final destination: The Ocean…