Ocean circulation
Marine debris from fluvial discharge, ship dumping and accidental discard.
Global pollution:
• ¾ UK beaches polluted with nurdles
• Fishery equipment and ropes; breakdown forms microplastics
• Most polluted place – Henderson Island, 17,000 tonnes plastic on uninhabited island
30,000 miles from mainland
• Overall plastic concentration 7x that of zooplankton
Microplastics:
= small pieces of plastic <5mm, 5 trillion particles globally
Engineered plastics – 1 microplastics
Released by run-off (agricultural fertilisers) and industrial processes (exfoliators)
Plastic breakdown – 2 microplastics
Formed by photodegradation rather than biodegradation
1992 plastic bath toys:
29,000 toys from China dispersed globally due to gyre between Japan, SE Alaska, Kodiak +
the Aleutian Islands (3-year circulation). Found on shores of Hawaii, frozen in Arctic ice and
on Scottish beach.
