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TRANSCRIPT
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t microplastics in the ocean
Small pieces of plas-c, commonly referred to as microplas-cs, were first described in the early 1970s and are widespread in the ocean.
Larger items made of plas-c, such as bags, rope and fishing nets, can have obvious direct impacts on marine life and society. But the effects of microplas-cs are more difficult to quan-fy.
sources, fate & effects
Microplas-c fragments from a beach in Hawaii © NOAA Marine Debris Programme
Microplas-c fragments from the western North Atlan-c, collected using a towed plankton net © Giora Proskurowski , SEA
This assessment should provide government, commerce, industry and society with a more reliable basis on which to base decisions.
what are microplastics? Plas-cs have become indispensible in many areas of modern life, used for clothing, storage, transporta-on, packaging, construc-on and a host of consumer goods. One of plas-c’s greatest proper-es, its durability, is also one of the main reasons that plas-cs present a threat to the marine environment. The risk increases as long as plas-c con-nues to enter the ocean. The term microplas-cs was introduced within the last decade to describe small pieces of plas-c found in the ocean, commonly defined as < 5mm in diameter.
Text box Secondary microplas-cs
The first scien-fic paper describing small plas-c fragments, found floa-ng in the northwest Atlan-c, was published in 1972. However, the aWen-on of the scien-fic community was aroused about a decade ago. Since then there has been an enormous increase in publica-ons about many different aspects of microplas-c distribu-on and behaviour.
Year
1970 1980 1990 2000 2010
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10
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30
40
50
Plastic pellets Microplastics
© Sarah Gall
One dis-nct category of microplas-cs are plas-c pellets. These represent one of the main ways of transpor-ng plas-cs between plas-cs producers and companies conver-ng plas-cs into products. Accidental spillages and poor handling mean that plas-c pellets are common on beaches, especially near ports and industrialised regions. Plas-c pellets © Hideshige Takada
Plas-c pellets and plas-c par-cles manufactured for par-cular applica-ons, such as cosme-c products and abrasives, are oXen called ‘primary’ microplas-cs. Microplas-cs produced as a result of fragmenta-on from larger items are called ‘secondary’ microplas-cs. The dis-nc-on is important as it can be used to pin-‐point sources and target reduc-on measures.
Microplas-cs in lips-ck © Heather Leslie
scope:
Ø key sources and types of microplas-cs
Ø weathering and fragmenta-on processes
Ø global distribu-on in the surface ocean using observa-ons and circula-on models
Ø physical and chemical effects on marine organisms
Ø social aspects, including public awareness
Ø key challenges and recommenda-ons
Ø materials science Ø marine ecology Ø physiology Ø ocean physics Ø ecotoxicology Ø chemistry Ø science-‐policy Ø public awareness and
communica-on
expertise:
the origins of microplastics
GESAMP was asked to conduct a global assessment, based on published informa-on, of the sources, fate and effects of microplas-cs in the marine environment. GESAMP (The Joint Group of Experts on the Scien-fic Aspects of Marine Protec-on) is an Inter-‐Agency body of the United Na-ons, set up in 1969 to provide authorita-ve and independent advice. The scope was defined by agreed Terms of Reference and the assessment carried out by a Working Group (2012-‐2014) with experts from a wide range of disciplines, working on a pro-‐bono basis.
Plas-c, a type of synthe-c polymer, may be derived from fossil-‐fuels or biomass. Global produc-on is dominated by a few well-‐known materials, but a huge range of plas-cs with differing composi-ons and proper-es are manufactured each year. Some microplas-cs are manufactured to fulfill par-cular func-ons, such as industrial abrasives or in domes-c cleaning and cosme-c products such as toothpaste.
The forma-on of ‘secondary’ microplas-cs, by fragmenta-on of larger ‘macro-‐size’ debris, is influenced by a combina-on of environmental factors and the proper-es of the polymer.
PE – polyethylene PP – polypropylene PS – polystyrene PVC – polyvinyl chloride
PET – polyethylene terephthalate PU – polyurethane SBR – styrene butadiene rubber
the assessment
EPS buoys © Korea Na-onal Marine Debris Monitoring program; EPS microplas-cs -‐ © Peter Kershaw
The produc-on of microplas-cs by the fragmenta-on of larger plas-c items is most effec-ve on beaches, with high UV irradia-on and physical abrasion by waves. Once submerged, cooler temperatures and reduced UV means fragmenta-on becomes extremely slow.
Macro-‐sized debris accounts for the larger por-on of plas-c in the ocean by mass (kg km-‐2) but micro-‐debris the larger propor-on by number (items km-‐2)
Example of regional difference in source and fate: large-‐scale use of expanded polystyrene (EPS) buoys for aquaculture in Korea
Generating microplastics
One 62 litre buoy
7,600,000 microplas-cs
(2.5 mm diameter)
7.6 x 1021 nanoplas-cs
(250 nm diameter)
v Different sizes of plas-c par-cle or larger plas-c objects need different types of equipment to sample them in the ocean and different analy-cal techniques in the laboratory. Size also determines the likely impact on ocean life and human ac-vi-es such as fisheries.
Par-cles in the size range 1 nm to < 5 mm were considered microplas-cs for the purposes of this assessment.
Sampling and isola-on:
Ø Mega-‐ & macro -‐sizes direct observa-on
Ø Meso-‐size sieving
Ø Micro-‐size towed plankton nets
Ø Nano-‐size filtra-on
Ø Mega-‐ & macro–sizes (entanglement) whales, seals, dolphins, turtles, fish, birds
Ø Meso-‐size unknown
Ø Micro-‐size unknown
Ø Nano-‐size unknown
Ø Macro–size whales, seals, dolphins, turtles & birds
Ø Meso-‐size birds, fish & invertebrates
Ø Micro-‐size fish, invertebrates & other filter feeders
Ø Nano-‐size invertebrates & other filter feeders
Direct external effects:
Direct & indirect internal effects (inges-on):
size is important
making sense of size
FT-‐IR Fourier-‐transform infra-‐red spectroscopy, Ramon spectroscopy, SEM scanning electron microscopy, TEM transmission electron microscopy, AFM atomic force microscopy, AFM-‐IR infra-‐red spectroscopy
Ø Commonly the term ‘microplas-cs’ is used to describe plas-c par-cles < 5 mm in diameter, which includes par-cles as small as 10 nanometres.
Ø Microplas-cs may be manufactured for par-cular industrial or domes-c applica-ons. These are referred to as ‘primary’ microplas-cs, and they can be released inadvertently into the ocean.
Ø Microplas-cs also occur as a result of the fragmenta-on of larger plas-c objects (termed ‘secondary’ microplas-cs).
Ø Plas-cs are discarded and enter the ocean as a result of many different land-‐ and sea-‐based ac-vi-es, but there are no reliable es-mates of the quan--es involved, at a regional or global scale.
Ø Microplas-cs are distributed throughout the ocean, occurring on shorelines, in surface waters and seabed sediments, from the Arc-c to Antarc-c. They may accumulate at remote loca-ons such as mid-‐ocean gyres, as well as close to popula-on centres, shipping routes and other major sources.
Ø Microplas-cs have been found inside the bodies of a wide variety of marine organisms including invertebrates, fish, birds and mammals.
Ø Plas-cs oXen contain chemicals added during manufacture and can absorb and concentrate contaminants such as pes-cides from the surrounding seawater. There is emerging evidence of transfer of chemicals from ingested plas-cs into -ssues.
Ø Very small (nano-‐size) microplas-cs have been shown to cross cell membranes, under laboratory condi-ons, causing -ssue damage.
Ø Ingested microplas-cs can affect the physiology of the host organism and poten-ally compromise its fitness.
Ø Public and private sector awareness of the poten-al nega-ve ecological, social and economic impacts of microplas-cs is much less developed than for macro-‐liWer.
Ø Effec-ve engagement and educa-on at all levels of society (public, government and private sector) is an essen-al tool to raise awareness and promote posi-ve behaviour change.
con
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Key ch
alleng
es & reco
mm
end
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s Action-orientated recommendations:
Challenge 1 – to reduce the entry of plastics and microplastics into the marine environment
Iden-fy the main sources and categories of plas-cs and microplas-cs entering the ocean:
• modelling, social and economic indicators, observa-ons
Challenge 2 – overcoming social, technical & economic barriers
U-lise end-‐of-‐life plas-c as a valuable resource as an important part of an overall waste reduc-on strategy:
• promo-ng reduc-on, re-‐use and recycling and the circular economy
Challenge 3 – influencing perceptions and behaviour, to complement legislation
Promote greater awareness of the impacts of plas-cs and microplas-cs in the marine environment:
• u-lize exper-se from the social sciences
Recommendations to improve a future assessment
Challenge 4 – assessing the risk from nano-plastics
Consider par-cles in the nano-‐size range in when assessing the impact of plas-cs in the sea:
• include exper-se from a wider range of disciplines, including pharmacology and mammalian toxicology; encourage greater research focus, including method development
Challenge 5 – assessing the importance of plastics and microplastics as a vector for the transfer of organisms
Evaluate the poten-al significance of plas-cs and microplas-cs as a vector for organisms
Challenge 6 – quantifying the chemical exposure risk from ingested microplastics
Evaluate the poten-al pathways and rates of chemical transfer and ecotoxicological risk:
• include exper-se on field & laboratory studies, animal behaviour, physiology and the gut environment for target species
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The assessment report: This brochure summarises the findings of GESAMP Working Group 40, on Sources, fate & effects of microplas6cs in the marine environment – a global assessment. The full assessment is scheduled for publica-on in early 2015, in the GESAMP Reports & Studies Series, available at www.gesamp.org . The lead Agency for the Working Group was the Intergovernmental Oceanographic Commission (IOC) of UNESCO, with the GESAMP Secretariat, based at the Interna-onal Mari-me Organiza-on (IMO), providing organisa-onal support.
Contributors to Working Group 40: Tony Andrady, Courtney Arthur, Joel Baker, Henk Bouwman, Sarah Gall, Valeria Hidalgo-‐Ruz, Peter Kershaw (Chair), Angela Koehler, Kara Lavender Law, Heather Leslie (Vice-‐Chair), Sabine Pahl, Jim Potemra, Peter Ryan, Won Joon Shim, Hideshige Takada, Richard Thompson, Alexander Turra, Dick Vethaak & Kayleigh Wyles
Acknowledgements: The following Agencies provided in-‐kind or financial support: IOC, IMO, UNIDO, UNEP, NOAA. In addi-on, the American Chemistry Council (ACC) and Plas-cs Europe (PE) provided generous financial support, without which the Working Group could not have func-oned. Ashley Carson (ACC), Keith Christman (ACC), Roberto Gomez (PE) and Ralph Schneider (PE) provided encouragement and technical advice on the plas-cs industry and related maWers. The assessment report was reviewed by Jesús Gago, François Galgani, Chelsea Rochman, Mar-n Thiel and Members of GESAMP, who provided very helpful cri-cisms and sugges-ons.
GESAMP (The Joint Group of Experts on Scien-fic Aspects of Marine Protec-on) is an inter-‐Agency Body of the United Na-ons, comprised of a group of independent scien-sts providing advice to UN Agencies on a wide variety of ocean maWers.
For more informa-on: www.gesamp.org [email protected]