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WEBSITE www.chem.uoa.gr /Scientific Reports.26 May, 2016
Global Plastic Waste Pollution
Million tons of plastic waste have gone missing
in the world oceans?
Athanasios Valavanidis
Department of Chemistry, University of Athens, University Campus Zografou, 15784 Athens,
Greece
Abstract. The extraordinary global expansion of manufactured of plastics, 300 Million tons in
2013, which have become indispensable for everyday use of our human civilization can be
seen in their dramatic rise of waste in every corner of land and water. The current global
annual production of plastic represents ∼40 kg for each of the 7 billion humans on the planet.
Plastic products have many advantages over older materials (glass, wood, leather, metals)
they are versatile, lightweight, flexible, moisture resistant, strong, and relatively inexpensive.
In the last decades, the massive globalization of single use food plastic packaging and thrown
away mentality, increased dramatically the volume of plastic waste in cities, beaches,
transportion by sea and industries. Studies showed that 40% of plastic waste goes to landfills,
14% is recycled but 32% ends in the marine environment as litter
found by selective surveys of waste to contain millions of tones of plastic pieces, mostly in the
form of microplastics. Since plastic are resistant to degradability under natural conditions it
takes years to break into pieces drifts under wind and surface currents into the marine
environment.
Recent studies had been shown that long-term surface transport (years) leads to the
accumulation of plastic litter in the center of the ocean basins. This could mean that plastic
pollution is moved more easily between oceanic gyres and between hemispheres than
previously thought. According to calculations millions of tons of plastic waste in the ocean
shave gone missing and are not accounted, so scientists wonder where where all these
plastics are missing?. The review covers the most important scientific studies and marine
surveys of the last years (until May 2016) concerning the plastic pollution and the widespread
appearance of microplastics in the ocean gyres and in the sea sediments even in remote
marine areas. Also, the review presents studies on the biodegradability of plastic waste in the
marine environment and their adverse effects on marine biota. Finally, the review presents
the various national and international policies in tackling the plastic pollution in the oceans.
Corresponding Author: Prof. A. Valavanidis, Dpt of Chemistry, University of Athens, valavanidis@chem.uoa.gr
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Introduction : Global Polymer and Plastics Production
The global production in 2014 of polymer materials and plastics reached 311
million metric tons, an increase of 3.9% from 299 in 2013. China is the largest
producer of plastics in the world, with around 25% of the global production. NAFTA
countries (USA, Canada, Mexico) produced 19.4%, the rest of Asia countries 16.4%
(India, Indonesia, South Korea, etc), the European countries (27 EU +Switzerland
+Norway) produced around 57 million metric tons (~20%) and Japan 4.4%.1,2
In Europe, there are 60,000 plastics factories, with 320 billion Euro annual
turnover, and direct employment of 1.45 million people. In the last decades the
European Union produced 25.2 million tons of post consumer plastics waste. Today,
an average person in developed countries consumes 100 kg of plastic each year,
mostly in the form of flexible packaging materials and household items.2
Figure 1. Global Plastics production was 300 million tons (Mt) in 2013, of which 57
million tons were produced in the European Union countries. The main producers of
plastics are China 25%, NAFTA countries (USA, Canada, Mexico) ~20%, EU27 20%.
Plasticsthe Facts 2014 [http://www.plastics.gl/market/plastics-the-facts-2014/].
Plastics Europe-The Facts 2014/2015 [www.plasticseurope.org/ ] (accessed April
2016).
Polymers, in general, are high molecular weight organic molecules, or
macromolecules, composed of many repeated subunits. Polymers range from
familiar synthetic plastics such as polystyrene (PS) and polyethylene (PE) to natural
biopolymers such as DNA and proteins. Plastics are referred to typically organic
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polymers of high molecular mass which are used for various technical applications. In
the last decades the plastics industry grows at a rate of 3-5% and is driven by growth
in end use markets, such as packaging, automotive, infrastructure, transport rails,
and telecommunication mainly from emerging economies (China, India, Brazil, South
Africa, South Korea, etc). Polymers and plastic materials in the last decades
continuously substitute metals, glass, paper and other traditional materials for a great
variety of applications due to their lightweight and strength, the design flexibility they
offer for any shape and durability, and especially the low cost.3,4
Plastic products have many advantages over older materials they are
versatile, lightweight, flexible, moisture resistant, strong, and relatively inexpensive.
Those are the attractive qualities that lead people all over the world to increase very
fast the consumption of plastic goods. Plastics are durable and very slow to degrade,
becoming ultimately persistent waste difficult to recycle. People are voracious
consumers of items that facilitated their activities at home, in factories and in small
businesses. Inevitably, large amounts of plastic are discarded daily. In the last
decade the production process used to make plastics consumed about 10% of oil
and gasoline both produced and imported by the U.S.A.4
Figure 2. Plastics and natural materials such as rubber or cellulose are composed of
very large molecules called polymers. In a linear polymer such as polyethylene,
rotations around carbon-carbon single bonds can allow the chains to bend or curl up
in various ways [http://chemwiki.ucdavis.edu/].
Global Plastic Waste. A Major Environmental Problem
Plastics are proving to be much more mobile than other man-made materials
such as ceramics, glass, wooden items, metals and paper. It took ceramics, glass,
wood and metals thousands of years to achieve anything resembling a global
distribution, with very little incursion into marine environments. From being a local
major environmental problem on land, in the water bodies and especially in the sea.
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Plastic items are not biodegradable, instead they degrade slowly into minute sized
microplastics (sizes from 1 mm to 1 m), which spread easily and pollute extensively
the marine environment causing the so-called microplastics pollution.5
Plastic waste encompasses a wide range of polymeric materials, including,
rubbers, elastomers, textiles, fibers, thermosets and thermoplastics, with some 200
plastics families in production including polyethylene (PE), high-density polyethylene
(HDPE) and low-density polyethylene (LDPE), polypropylene (PP), polystyrene (PS),
polyvinylchloride (PVC) or Vinyl (V), polyethylene terephthalate (PET), Polycarbonate
(Other plastic, suitable for food), nylon, polyvinyl alcohol (PVA) and acrylonitrile
butadiene styrene (ABS) synthetic rubbers. Plastics can be fabricated from feed-
stocks derived from petroleum, natural gas, or bio-renewables.
Figure 3. The majority of plastic material can be recycled after use but need to be
separated at source and be clean to feed the recycling process.
In response, there has been a rapidly expanding body of scientific papers on
the subject within the last few years and many innovative research projects are trying
to establish the fate of million tons of plastic waste in the world oceans. The
extraordinary global expansion of manufactured of plastics, which have become
indispensable for everyday use of our human civilization, is causing problems for the
marine environment. The current global annual production of plastic represents ∼40
kg for each of the 7 billion humans on the planet, and more than ~100 Kg plastic
production in developed countries.6-8
Scientists tried in the past to estimate the overall plastic waste in the form of
municipal garbage, fishing gears, plastic tools, kitchen utensils, food packaging,
pellets, plastic bags and bottles of water and soft drinks. Most of researchers realized
that there are no reliable estimates of the amount of global plastic litter or debris that
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pollute land and water bodies and how much plastic waste reaches the marine
environment from land-based activities, but all realized from production statistics that
the quantities of plastic waste were nevertheless quite substantial.9
Figure 3. Millions of tons of plastic litter end up floating in world oceans broken into
microplastics, the so-called plastic soup. Microplastics are found in the most remote
parts of our oceans.
Various scientific reports from the 1970s appeared in the scientific literature
with rough estimates of plastic waste at national and global scale. One study in 1975
estimated that the world's fishing fleet alone dumped into the sea approximately
135,400 tons annually of plastic fishing gear and 23,600 tons of synthetic packaging
material.10 Merchant vessels were investigated and found to be notorious polluters of
seas with their plastic waste. A study estimated that in the 1980 more than 630,000
plastic containers were disposed each day from merchant ships in the seas, although
the disposal at sea of plastic materials (garbage except food waste) is against the
Inter-Governmental Marine Consultative Organization (IMCO, 1973 regulations).11,12
Also, plastic pollution in the seas is caused by recreational fishing boats as it was
established by US Coast Guards. According to their estimation more than 50% of
garbage dumped in US waters is from recreational fishing boats.13
Land-based sources (industrial facilities, recreational beaches, inadequate
waste facilities in coastal areas, dumping of municipal waste in surface landfills) have
been proved to be major plastics polluters compared to sea-based sources. 14,15,16
There are so many applications of produced polymers that large amounts of plastic
materials end up in the marine environment when accidentally lost, carelessly
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handled or left behind by tourists and bathers in beaches.17,18 Rivers and municipal
drainage systems can become carriers of plastic waste to the nearest shoreline and
then at sea.19
Figure 4. Rivers can become major dumping areas of consumer plastic and
subsequently carriers of municipal plastic waste to the oceans.
Other sea-based sources of plastic pollution include oil and gas platforms,
aquaculture facilities, cargo ships and other vessels that throw or lose plastic
containers to the sea. Studies showed that plastic debris and waste from land comes
primarily from two sources: first, ordinary litter; and, second, material disposed in
open dumps or landfills that blows or washes away, entering the ocean from inland
waterways, wastewater outflows, and the wind. Also, major waterways (rivers) can
transport a great deal of plastic waste. A project estimated that the Danube River, for
example, transports 4.2 metric tons of plastic into the Black Sea each day.20
Lightweight plastic items tend to float in water and can be carried by currents
great distances. For example, it has been reported that plastic cargo lost from ships
has been found more than 10,000 kilometers from where it was lost. Also, currents
can carry floating fishing nets hundreds of miles from where they were last used, as
is the case with Northwestern Hawaiian Islands (collection efforts there rounded up
about 52 metric tons of lost nets and other plastic debris).21
Managing municipal, industrial and packaging solid waste has become a big
environmental issue in advanced industrial societies. In the last decade very effective
and technologically advanced methods of plastic recycling is applied in many
countries. There are numerous recycling methodologies and management initiative in
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a broad range of plastic materials. The most important is considered the separation
at source and recycling or incinerating at high temperature for electricity generation
and hot water for heating.22,23
Figure 5. Recycling of plastic waste has been proved to be very effective for the
production of the initial feedstock polymer material. It is vital for plastic waste to be
clean and separated at source foe efficient recycling.
The majority of the Life Cycle Assessment (LCA) studies concluded that,
when single polymer plastic waste fractions with little organic contamination are
recycled and replace virgin plastic at equivalent amount, recycling can be the
environmentally preferred treatment option, compared to municipal solid waste
incineration for electricity production and hot water. Also, feedstock recycling and the
use of plastic waste as a solid recovered fuel in cement kilns were preferred to
municipal solid waste incineration. Landfilling of plastic waste compared to municipal
solid waste incineration proved to be the least preferred option for all impact
categories.24
Plastic Pollution is Ubiquitous in the World Oceans
After a decade of intensive studies in all marine areas, seas and oceans,
scientists now know that plastic waste has become nearly ubiquitous on the marine
environment of the planet. Even in the remote shores of Alaska plastic was found
floating of littering the beaches. Plastic waste has washed up on the most remote
beaches of the continents, amassed in distant gyres (a gyre in oceanography is
large system of rotating ocean currents involving with large wind movements), and
has been discovered in the bodies of dead organisms from fish to birds to whales.
One study evaluated the abundance of anthropogenic debris on 37 sandy beaches
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bordering the Salish Sea in Washington State and plastic debris in surface waters of
the Salish Sea and the Inside Passage to Skagway, Alaska.25-27
Plastic waste has been found in marine animals since the early 20th century,
but little is known about the impacts of the ingestion of debris in large marine
mammals (like sperm whales) related to the ingestion of large amounts of marine
debris in the Mediterranean Sea. The spatial distribution modeled for the species in
the region showed that these marine animals can be seen near the waters of
These plastic
materials can cause death by gastric rupture following impaction with debris.28 Plastic
ingestion of plastics debris, along with adsorbed toxic chemicals, by marine biota.29,30
Large filter feeding marine organisms consume daily large amounts of
microplastics waste (size 5 mm). Studies showed that Mediterranean fin whale
(Balaenoptera physalus) and basking shark (Cetorhinus maximus) showed high
concentrations of phthalates (MEHP) in their blubber due to the feeding with plastic
waste.31
Figure 6. It has been estimated that 640,000 tons of fishing gear is lost in our oceans
every single year. Thousands of sea mammals become entangled and trapped in
. Ingestion of plastics waste,
along with adsorbed toxic chemicals, can cause death to large section of marine
biota.
The oceans on Earth
the habitable space on the planet. The Pacific ocean covers 28% of
surface, the Atlantic is half size of the Pacific, the Indian ocean is largest than the
landmass of Eurasia, the Southern ocean contains cold waters that encircle the
Antarctic continent and the Arctic ocean that is almost the same size as the Antarctic
continent. The oceans remain home to several hundred thousand of different plant
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and animal species and they are essential to all living beings, both in the water and
on land. The oceans also play an essential role in the carbon cycle, and currently
absorb about half of all of the atmospheric carbon, thereby reducing or slowing the
effects of global warming.32
Solid plastic waste in the vast oceans s is considered now as one
of the most important pollution factor (petroleum spills, agricultural effluents,
industrial and municipal liquid waste, etc) that is moved throughout the world's
oceans by the prevailing winds and surface currents. This had been shown for the
Northern hemisphere where long-term surface transport (years) leads to the
accumulation of plastic litter in the center of the ocean basins.33,34
Results from studies confirm similar patterns for all southern hemisphere
oceans. Surprisingly, the total amounts of plastics determined for the southern
hemisphere oceans are within the same range as for the northern hemisphere
oceans, which is unexpected given that inputs are substantially higher in the northern
than in the southern hemisphere. This could mean that plastic pollution is moved
more easily between oceanic gyres and between hemispheres than previously
assumed leading to redistribution of plastic items through transport via oceanic
currents. Furthermore, there might also be important sources of plastic pollution in
the southern hemisphere that had not been accounted for, such as currents from the
Bay of Bengal that cross the equator south of Indonesia.35
Degradation of Plastic Waste and Biodegradable Polymers
Synthetic polymers are recognized as persistent environmental pollutants that
take years to disintegrate by chemical, physical and biological factors in the natural
environment. Despite the new biodegradable polymers that have been introduced in
the market in recent years, the problems of environmental plastic pollution have
increased substantially. Polymers which are easy digestible by microorganisms,
chemically modified starch, starch-polymer composites, thermoplastic starch,
biodegradable packing materials, and biopolyesters (poly--hydroxyalkanoates) have
decreased to a limited degree the plastic waste in the last decade. The main problem
associated with designing biodegradable polymers is the optimization of their
chemical, physical and/or mechanical properties, as well as their biodegradability.36
Most plastic materials are categorized by their durability, exceptional
mechanical properties, flexibility and can be molded in a great variety of shapes. The
multiple applications of plastic materials and the widespread pollution caused in the
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last decades advanced many studies on their biodegradability under natural
conditions. Studies have been contacted for the microbial colonization and
degradation of polyethylene (PE) plastic bags and other polymers. All studies
showed that plastics take long time to disintegrate into oligomers, monomeric
constituents, other low molecular chemicals or carbon dioxide.37,38
Figure 7. Polymers can disintegrate under the influence of oxygen, reactive oxygen
species (oxidations of chemical bonds), UV-radiation (photochemical reactions, bond
dissociation), surface weathering, cracking under wind and sea current forces, and
finally by microorganisms decomposing plastic materials.
Many polymer companies researched and tested different types of
biodegradable plastics. At present there are many commercially available
biodegradable plastic materials, such as natural plastics produced by
microorganisms, or plastics with polymer blends, such as starch and photo-
biodegradable plastics. Typically, these are made from renewable raw materials such
as starch or cellulose. Interest in biodegradable plastic packaging arises primarily
from their use of renewable raw materials (crops instead of crude oil) and end-of-life
waste management by composting or anaerobic digestion to reduce landfilling.39,40,41
Various studies were conducted on the degradability (laboratory tests) of different
types of degradable plastics in a variety of marine environments.42,43
These studies produced conflicting results and it remains unclear whether
degradable plastics are less harmful than conventional plastic. Bacteria and microbes
are ubiquitously abundant in the marine environment, capable of decomposing
complex organic matter but plastic materials are compact chemical polymers with
strong chemical bonds and toxic additives to make them mechanically strong and
flexible. Hence, the question arises whether microbial degradation of plastic waste is
possible and whether it has the capacity to decompose them and reduce the gradual
accumulation of plastics in various marine environments. Most of the studies on
microbiological degradation of plastic are restricted to the upper ocean layer. Plastic
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has a longer half-life than most natural floating marine substrates, and a hydrophobic
surface that promotes microbial colonization and biofilm formation, differing from
autochthonous substrates in the upper layers of the ocean. A study described a
diverse microbial community growing on plastic material from North Atlantic surface
water, which differed from the bacterial composition of the surrounding water.
Biodegradation of polymers has been proved to be a slow process.44
Figure 8. Biodegradable plastic materials ut still last for a long
time in the environment. Hydrolytic degradation has certain environmental
requirements, a material may degrade readily in one environment and be long-lasting
in another.
Resistivity of plastic waste to chemical weathering, mechanical erosion, and
biological degradation has become a big environmental problem. Plastic waste has
increased in abundance over the past several decades along shorelines, beaches,
rivers and in open sea. In a study, highly used polyethylene plastic (PE), was
incubated for 20 months in 2 m water depth in the Baltic Sea but showed no
biodegradation.45 The initial positive buoyancy and the hydrophobicity of PE may be
altered by UVradiation, oxidation, high temperatures and biofilm formation. After 3
weeks of floating at the ocean surface, PE bags start to sink below the seawaterair
interface.46 Adhesion of more particles onto the PE surfaces and wind-induced
downwelling caused bags to sink further, until eventually they settle onto the
seafloor.47 In great depth of the sea water the light decreases and the rate of abiotic
plastic degradation decreases in deep waters. Although there are restricted data on
the dimension of plastic pollution of the seabed at depths more than 30 meters,
plastic debris litter has been found on the seafloor of every ocean.48,49
It has been found that on the continental slope and in bathyal plain of the
northwestern Mediterranean Sea 70% of the total debris consisted of plastic bags.
Once on the ocean floor, plastic material is buried into the seabed by ongoing
sedimentation and passes the thin oxygenic surface layer before reaching the anoxic
sediment below. It is unknown how degradation rates of plastic in sediments are
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affected by the lack of oxygen and light. Different types of debris were observed,
particularly pieces of plastic bottles, glass bottles, glass vials, and fishing gear. The
results showed considerable geographical variation in concentrations, which ranged
from zero to 101,000 pieces of waste per km2.50 As microorganisms in the sediment
largely control carbon sequestration and nitrogen conversion, play an important role
in marine biochemical cycles and are crucial in biological degradation of deposited
plastic litter.51
Figure 9. The degradation of plastic items produce a vast number of small sized
plastic beads, microplastics (<1 mm) that spread in the sand in the sea beds.
The predominant type of plastic PE appears to be much more resistant to
chemical weathering than polypropylene (PP), as indicated by studies of FTIR
spectra suggesting that PP degrades more readily under natural conditions on
freshwater beaches.52 The degradation of plastic in the marine beaches and at
sea produces small sized pieces (microplastics) which spread in the sand and
sea sediment beds. A recent study showed that microplastics (<1 mm, 0.001 m) that
originate by degradation of larger plastic waste items have reached the most remote
of deep sea environments. Also, the study found smaller plastic particles sized in the
micrometer (m, 1 m = 10-6 m). The abundance of up to 1 microplastic per 25 cm3
was observed in deep-sea sediments collected at four locations (Atlantic Ocean and
Mediterranean Sea) representing different deep-sea habitats ranging in depth from
1,100 to 5,000 meters.53
These microplastics retain all the properties of polymers and in this respect
represent a potential danger to marine ecosystems from the accumulation of toxic
plastic debris on the sea floor. The accumulation of such debris can inhibit gas
exchange between the overlying waters and the pore waters of the sediments, and
disrupt or smother inhabitants of the benthos. Also, albatross, fulmars, shearwaters
and fish mistake floating plastics and microplastics in the beaches and in the sand
floor for food. Studies showed that around 40% of all seabird species are known to
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ingest plastic litter with their food. Sea turtles and cetaceans ingest plastic bags,
fishing line and other small sized microplastics. Around 267 species of marine
organisms worldwide are known to have been affected by plastic debris.54 Synthetic
polymers in the marine environment and microplastics in deep-sea sediments are
considered by many scientists as a long-term threat for the environment.55,56
Biodegradable Plastics: Solution to the Plastic Waste?
From the 1970s plastic producers investigated the application of
biodegradable plastics as a solution to the environmental problem of plastic waste. At
present there are mainly two types of biodegradable plastic on the market : a) plastic
materials that are plant-based hydro-biodegradable plastic (polylactic acid, PLA,
made from corn starch or cellulose, polyhydroxyalkanoate) and b) petroleum-based
(polyolefins), with transition metals and oxo-biodegradable (OBD) plastic, that require
a great deal of time to degrade under certain circumstances.57
Figure 10. There is a great variety of biodegradable plastics. But, biodegradable
plastics are not the answer to reducing marine litter, says the United Nations
Environment Programme (UNEP). Kershaw PJ. Biodegradable Plastics and Marine
Litter. Misconceptions, Concerns and Impacts on Marine Environments. UNEP
publications, Nairobi, 2015.58
In 2015, a study by UNEP and partners (commissioned by Global Programme
of Action for the Protection of the Marine Environment, and Land-based Activities)
estimated that from 280 million tons of plastic produced globally each year, only a
very small percentage is recycled. Instead, some of that plastic ends up in the world's
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oceans, costing several billion dollars annually in environmental damage to marine
ecosystems. The report argued that widespread adoption of products labelled
of plastic entering the
ocean or the physical and chemical risks that plastics pose to marine environment.
This report showed that there are no quick fixes, and a more responsible approach to
managing the lifecycle of plastics will be needed to reduce their impacts on our
oceans and ecosystems.58
Oxo-biodegradable (OBD) plastic is conventional polyolefin plastic with an
added small amounts of metal salts [there are no "heavy metals" which are restricted
under the EU Packaging Waste Directive 94/62 Art 11)]. These salts catalyze the
degradation process to speed it up so that the OBD plastic will degrade abiotically at
the end of its useful life in the presence of oxygen much more quickly than ordinary
plastic. At the end of that process it is no longer a plastic as it has been converted via
carboxylation or hydroxylation reactions to small-chain organic chemicals that will
then biodegrade.59,60
Figure 10. Samples of starch-based biodegradable plastic mulch (BioTELO)
recovered after 24 months burial in the field at three experimental locations. (Photo
credit: J. Moore-Kucera, Texas Tech University10).[http://articles.extension.org/
pages/67951/current-and-future-prospects-for-biodegradable-plastic-mulch-in-
certified-organic-production-systems].
OBD plastics have to pass the eco-toxicity tests (ASTM D6954); additionally
they must be designed not to degrade deep in landfill so that they will not generate
methane. There is no evidence of any danger to wildlife from OBD; almost all the
plastic fragments found in studies on the marine environment are fragments of
conventional plastic, unsurprisingly as this still makes up the vast majority of
plastics.61,62
There are various problems with biodegradable plastic bags and criticisms
from environmentalists. The first criticism concerns research which showed that
plastic bags do not degrade completely as the producers are claiming. And second,
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priming plastic bags for destruction is itself an ecological crime. Supermarkets in
England distributing biodegradable bags to consumers claim that "bags are able to
degrade completely within about 3 years, compared to standard bags which take 100
years or longer". The big supermarket Tesco reckons that bags will decompose
within 18 months "without leaving anything that could harm the environment". But
whether it actually happens seems to depend a lot on where the "biodegradable"
plastic ends up. If it gets buried in a landfill it probably won't degrade at all because
there is no light or oxygen.63
In general, most of the plastics used at present do not degrade to a large
degree when released in to the environment. Photodegradation by UV radiation,
thermo-oxidation, hydrolytic degradation and action of microorganisms are the most
important mechanisms to degrade polymers. New plastic products incorporate
chemical additives to achieve polymers, after use, to become brittle and then break
down into smaller pieces. When polymers reach sufficiently low molecular weight can
be metabolized by microorganisms which convert them into CO2 or incorporate it into
biomolecules. However this process is very slow and it can take 20-30 years to fully
break down. Biodegradable plastics accelerate this process, but these processes
decreased in seawater due to lower temperature and lack of oxygen.64,65,66
An extensive report in Belgium in 2013 compared the benefits and challenges
of biodegradable and oxo-degradable polymers for the environment. The results of
the literature showed that there are various problems of degradability in the long-term
and the use of biodegradable plastic to mitigate environmental marine pollution.67
For a manufacturer to employ the claim of biodegradability of plastic
materials, a set of specified standards need to be met. ASTM International (formerly,
American Society for Testing and Materials) has prepared standards to measure
biodegradability (ASTM D6400). The ASTM D6400 encompasses several ASTM
standardized tests, such as the "inherent biodegradability" of the plastic material via
ASTM D5988-on
(C) atoms to CO2, over time (90% of C atoms must be mineralized, that is, converted
to CO2 within 180 days by microorganisms (ASTM, 2003). In the laboratory, CO2
release is measured through a relatively inexpensive titration method.68,69
Plastic films (mostly PE) are used in agriculture and particularly in protected
horticulture (mulching, low tunnels, greenhouses). The market of plastics used for
these purposes in Europe involves hundreds of thousands of hectares and
thousands of tons of plastic films per year. The conventional agricultural plastic films
used today are high and low density polyethylenes, PVC, polybutylene or copolymers
17
of ethylene with vinyl acetate. A major negative consequence of this expanding use
of plastics in agriculture is related to plastic wastes and the associated environmental
impact (a small percentage is recycled). A large portion of this plastic is left on the
fields or burnt uncontrollably by the farmers releasing harmful substances. Several
experimental biodegradable agricultural films have been exposed in the fields under
real cultivation conditions in several locations in Europe, as well as in the laboratory.
The Mater-Bi grade NF 803/P was found to be best suited for blow extrusion of thin
biodegradable agricultural films. It has been shown that it is possible to develop very
thin biodegradable mulching films made of this grade that perform satisfactory for the
specific applications and may replace conventional (thicker) polyethylene films.70,71,72
Figure 11. Agricultural plastic mulch films increased substantially in the last decades
leading to environmental pollution. Rigorous research in the last decade aimed to
develop degradable agriculture mulch film and films for greenhouses.
The dramatic increase in plastic film mulching in water-efficient agriculture is
primarily due to its versatile nature that has proven to be very beneficial over the last
decade in the arid region. However, as carelessly used plastic mulch films lead to
agro-environmental pollution, there has been vigorous research recently to develop
degradable film materials for mulching. This review describes the use of plastic film
for mulching in water-efficient agriculture practices with special reference to progress
made in degradable film materials. Moreover, this review includes water-efficient
mechanisms and techniques of mulching film cultivation, photodegradable and
biodegradable plastic polymers (PHA, PCL etc. synthetic- and natural-based
polymers films), their degradation process and developmental deficiencies, and an
outlook of degradable film materials. There exists great potential for the further
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development of water-efficient agriculture; however, it is dependent upon effective
research and the wide-spectrum applications of degradable film materials.73
Figure 12. Silage in agriculture was developed with plastic films (very resistant) to
straw during the winter.. Degradation steps of P-Life
degradable plastics. After completion of their lifetime as plastic products, plastics with
P-Life additive start to degrade once they are disposed in the natural environment.
[ http://www.p-life.com.hk/en/page/WsPage.php?news_id=3 ] (accessed May 2016).
Bioplastic production which are biodegradable has been expanded in the last
years with new products in the market. The future prospects were presented in
various studies, but the problem of plastic waste in the environment and especially in
the marine environment remains a crucial problem.74,75
In the USA various biodegradable plastic products are available in the market
and some of them were tested for house compost facilities. An environmental
organization tested 5 types of bioplastic bags to see how well they would compost.
The test showed that none of them broke down completely after 25 weeks in home
compost conditions (shredded, mixed and 77 degree Fahrenheit, 25oC). A product
from Italian bioplastic manufacturer Novamont came closest to what be truly
compostable, with a product called Mater-bi is a biodegradable and compostable
bioplastics developed over twenty-five years of research by using corn starches,
cellulose, vegetable oils and biodegradable synthetic polyesters. MATER-bi plastics
are certified by certification bodies in accordance with the main European and
international standards. Also, they tested one type of Oxo-Biodegradable bag which
did not begin to break down even after 25 weeks at 140 degrees F (60oC). The study
concluded that most bioplastic products currently being marketed (USA) carry
19
incomplete and/or misleading labeling. Also, they tested packaging developed by
Frito-Lay for its S renewable, plant-based materials. Tests
showed that the bags disintegrated down completely into compost in a hot, active
home or industrial compost pile.76
The Institute for Local Self-Reliance (est. 1974, Washington DC, USA) tested
several biodegradable products from conventional plastics and their claims for
biodegradability by the manufacturers [BioGreen bottle of LDPR, Aquanatra ENSO,
water bottle from PET, PerfGo Green biodegradable plastic bags, PolyGreen PE
plastic newspaper bags (oxo-biodegradable), PlanetGreen Bottle Corporation,
Reverte oxo-degradable PET bottle, etc]. The report concluded that most of these
claims were unsubstantiated. The companies selling these products were taking
advantage of markets that are unaware of the difference between certifiable
compostable and biodegradable products and those that are not.77
Packaging plastic materials (plastic and paper particularly food packaging
which is discarded after use), as well as plastic bags are causing great headaches to
environmentalists because they represent a severe source of pollution when
recycling fails. Whereas paper consists of the natural polymer cellulose, most
synthetic packaging polymers are based on polyethylene (PE), which has a much
lower weight, higher strength, and causes less pollution during production.
Biodegradation and bioerosion render plastics brittle so that they readily disintegrate
when exposed to mechanical stresses. Plastics break into microplastics form much
(dust-like micron- and nanometer-sized particles), which are carried away by wind or
rain and accumulate in the marine environment. Scientists today recognized that
CO2
and water. Biodegradation can also produce water-soluble and even toxic
metabolites that are washed away by rain and thus pollute groundwater and the
marine environment.78
The degradation potential of plastic litter in the marine environment inevitable
remains a crucial factor on how long plastic waste persist in the sea and how it
disintegrate into smaller pieces. A recent study in Greece collected from the
submarine environment (Saronikos Gulf) polyethylene terephthalate bottle (PET, for
water and soft drinks) which were characterized using infrared spectroscopic
techniques (ATR-FTIR) to investigate their degradation potential. The study showed
that PET bottles remain robust for around 15 years and afterwards start to
disintegrate.79
20
Plastic Debris, Microplastics, and Ocean Pollution Worldwide
Concern about the potential impact of microplastics in the marine
environment has gathered momentum during the past few years. The number of
scientific investigations has increased, along with public interest and pressure on
decision makers to respond. The extent to which microplastics represent a hazard to
marine life and may provide a pathway for transport of harmful chemicals through
the food web is still being assessed. A number of international initiatives are under
way to determine the physical and chemical effects of microplastics in the ocean, and
to identify ways to address this emerging issue.80,81,82
It was in 2004 for the first time that the presence of microplastics was
described in the shorelines and in water column of the oceans. In the beginning
microplastics were identified as small plastic pieces (plastic litter breaking under
photodegradation and oxidative reactions, and mechanical abrasion) around 50 m
in size. Later studies on microplastics extended the characterization to smaller than 5
mm in size.83,84
Figure 13. Microplastics are widespread in the sea surface, on shorelines and on the
sea beds of many marine areas and oceans.
Over the past decade (2004-2014), a large number of scientific publications on
microplastics pollution in the marine environment were published in four main
journals (high-impact journals), which together were responsible for around 63% (68
articles) of all published articles (Marine Pollution Bulletin (30%), Environmental
Science and Technology, Environmental Pollution and Marine Environmental
Research.85
21
Analysis of scientific data published for the microplastic debris in the marine
environment showed that the most important classes of plastics were polyethylene
(PE), polypropylene (PP), polystyrene (PS), and polyvinyl chloride (PVC). This plastic
litter proliferate, migrate, and accumulate in natural habitats from pole to pole and
from the ocean surface to the bottom of the sea.86,87
The majority of the studies over the past decade on microplastics pollution in
the marine environment were from USA and Western Europe, South Korea, China
and Japan scientists. Most of these studies focused on the measurements of the
concentrations of microparticles in the marine environment, including areas that are
naturally protected as well as more remote ones. Although scientific evidence has
quickly been reported in the scientific literature regarding the fate of microplastics
and their impact on these environmental systems, many critical issues are still poorly
understood (like trends of transport, fate after many years, physicochemical effects
on their structure, and impact on the marine environment and biota).88,89,90,91
Figure 14. Microplastics. Samples collected in the bottom of oceans polluted by
macro (>2.5cm) and micro (<5mm) debris. Microplastics have been measured in
protected and in remote areas of the oceans.
Due to their minute size and their presence in both pelagic and benthic
ecosystems, a growing number of scientific studies and surveys showed that
microplastics are potentially bioavailable for ingestion by a wide range of organisms.
Several studies report that these particles may be ingested by invertebrates, e.g.,
polychaetes, crustaceans, echinoderms, bryozoans, and bivalves, as well as
vertebrates such as fishes and birds, in addition to plankton and zooplankton
organisms.92,93,94
22
Other studies investigated the bioaccumulation by absorption of toxic
chemicals into the pores of microplastics and their transport and later release in the
marine environment. It has been shown that persistent organic pollutants (POPs),
metals and other pollutants that occur universally in sea water at very low
concentrations are picked up by meso-/microplastics via partitioning because of the
hydrophobicity of POPs that facilitate their concentration in the meso-/microplastic
litter at a concentration that is several orders of magnitude higher than that in sea
water. These contaminated microplastics when ingested by marine species present a
credible route by which the POPs can enter the marine food web. The extent of
bioavailability of POPs dissolved in the microplastics to the biota and their potential
bio-magnification in the food web has not been studied in detail. Once ingested, the
absorbed contaminants enter the bodies and metabolism of marine organisms. The
interactions inside their bodies alter the distribution, biotransformation and toxicity of
environmental contaminants. This may lead to an increase in the concentration of
contaminants and the potential risk for these to be incorporated into superior trophic
chains, thus threatening the health of marine animals. 95,96,97
A large number of studies provided data on the impact of plastic waste and
microplastics to wildlife and especially seabird species. A recent study performed a
spatial risk analysis using predicted debris distributions for 186 seabird species and
adjusted the model using published data on plastic ingestion by seabirds. The study
found that 60% of species (scientific studies from 1962 to 2012) had ingested plastic
litter. Also, on average 29% of individual seabird species had plastic in their gut. The
study observed that the highest area of expected impact by plastic waste in seabirds
occured at the Southern Ocean boundary in the Tasman Sea between Australia and
New Zealand. The scientists predicted that plastics ingestion will increase in seabirds
and it will reach 99% of all species by 2050.98
Figure 15. Scientists scrutinized the impact of plastic waste on seabirds such as
albatrosses and shearwaters.
contained plastic litter mistaken for food (on the left Puffinus tenuirostris).
23
Another aspect of plastic waste is the transfer of plastic derived toxic
chemicals, like polybrominated diphenyl ethers (PBDEs) in the abdominal adipose of
oceanic seabirds (short-tailed shearwaters, Puffinus tenuirostris). A study by
Japanese scientists detected in samples collected from the guts of seabirds in North
Pacific Ocean, higher-brominated congeners (PBDEs). These compounds were not
present in pelagic fish (the food of seabirds). PBDEs were detected in plastic waste
found in the stomachs of birds. According to the study these data suggested the
transfer of plastic-derived chemicals from ingested plastics to the gut tissues of
seabirds.99 Plastic ingestion is generally considered to be a more serious
environmental and toxicity problem for marine animals than entanglement in marine
debris because large proportions of wildlife populations are affected. Among
seabirds, the albatrosses and petrels (Procellariiformes) have particularly high
incidences of ingestion of plastic waste, with many species having plastic in more
than half of all individuals examined.100-102
Microplastics in the marine environment can be digested by zooplankton and
thus enter the planktonic food web. Recent studies focused on the issue of potential
threats of microplastics on simple grazing experiments with fluorescent microspheres
and zooplankton. A study tested experimentally the potential of different Baltic Sea
zooplankton organisms and consisted of two parts: a) direct ingestion experiments
with zooplankton and b) studies on food web transfer of microplastics. Mysid
shrimps, copepods, cladocerans, rotifers, polychaete larvae and ciliates were
exposed to 10 m fluorescent polystyrene microspheres. These experiments showed
ingestion of microspheres in all taxa studied. The highest percentage of individuals
with ingested spheres was found in pelagic polychaete larvae, Marenzelleria spp.
Microscopy observations of mysid intestine showed the presence of zooplankton
prey and microspheres after 3 h incubation.103
Figure 16. Microplastics can be ingested by zooplankton organisms and can be
detected by bioimaging techniques (using fluorescent polystyrene microspheres).
[http://pubs.acs.org/doi/abs/10.1021/es400663f].
24
Another study showed that microplastics are ingested by, and may impact
upon, zooplankton. Scientists used bioimaging techniques to document ingestion and
adherence of microplastics in a range of zooplankton common to the northeast
Atlantic. Using fluorescence and coherent anti-Stokes Raman scattering (CARS)
microscopy they identified that 13 zooplankton taxa had the capacity to ingest 1.7
30.6 m polystyrene beads.104
Studies showed that microplastics can be digested by fish as has been
observed in various marine habitats worldwide and in laboratory studies. One of the
many studies in the last decade, detected microplastics in 10 species of fish from the
English Channel. The study examined more than 500 fish were examined and found
microplastic beads in the gastrointestinal tracts of 35% of fish. A total of 351 pieces
of plastic were identified using FT-IR Spectroscopy; polyamide. The study showed
that there was no significant difference between the abundance of plastic ingested by
pelagic and demersal (live and feed near the bottom of seas) fish. 30 Another study
focused on the presence of plastic debris in the stomach contents of large pelagic
fish (Xiphias gladius, Thunnus thynnus and Thunnus alalunga) caught in the
Mediterranean Sea (2012-2013). Around 20% of fish were found to have ingested
plastic waste from the marine environment: microplastics (<5 mm), mesoplastics (5
25 mm) and macroplastics (>25 mm). The results showed that around 30% of bluefin
tuna (representing endangered species by IUCN) have micro-, meso- and macro-
plastics in their gut tissues.105
Plastic Waste in the Oceans and Ocean Gyres
In the last years there is a rising concern among scientists and
environmentalists regarding the accumulation of floating plastic debris in the open
oceans, the quality of ocean waters and their marine biota. The magnitude and the
fate of this pollution, especially the predominance of plastic waste, are still open
questions. Regional surveys, and previously published reports, showed a worldwide
distribution of plastic waste on the surface of the open ocean, mostly accumulating in
the convergence zones of each of the five subtropical gyres with comparable density.
Also, the global load of plastic on the open ocean surface was estimated to be on the
order of tens of thousands of tons, far less than expected. The most well-publicized
-scale anticyclonic (clockwise) ocean circulation
acts to trap and retain floating debris, especially plastic waste. Despite the increasing
25
research efforts to understanding the spatial distribution and temporal variance of
marine plastic waste, the ecological implications are still largely unknown, particularly
in regard to the potential consequences for lower tropic levels (e.g., phytoplankton
and marine bacteria).106
Figure 17. Ocean gyres circle large areas of stationary calm water. Debris and litter
especially plastic waste, drift into these areas and, due to the
movement, can accumulate for years. These regions are called garbage patches.
The Indian Ocean, North Atlantic Ocean, and North Pacific Ocean all have significant
litter patches. [Science Learning. http://sciencelearn.org.nz/Contexts/The-Ocean-in-
Action/Sci-Media/Images/Map-of-ocean-gyres and National Geographic. Ocean
Gyres, http://education.nationalgeographic.org/encyclopedia/ocean-gyre/].
A working group of researchers estimated that just 20 countries, out of a total
of 192 countries with extensive coastlines (2-5 km), are responsible for 83% of the
countries produce some 275 million metric tons (Mt) of plastic waste each year, of
which 4.812.7 million metric tons of mismanaged plastic waste is thought to have
entered the ocean in 2010. Scientists emphasized that, without improvements to
waste management infrastructure, with recent increased coastal populations
economic growth, and increased use of plastic materials, the volume of plastic waste
in the oceans could more than double by 2025.107
In 2014 another important study observed that the size distribution of floating
plastic debris point at important size-selective sinks removing millimeter-sized (mm)
fragments of floating plastic on a large scale. This sink may involve a combination of
fast nano-fragmentation of the microplastic into particles of microns or smaller, their
transference to the ocean interior by food webs and ballasting processes, and
26
processes yet to be discovered. Resolving the fate of the missing plastic debris is of
fundamental importance to determine the nature and significance of the impacts of
plastic pollution in the ocean. The dataset collected from the circumnavigation cruise
[Malaspina 2010 expedition, floating plastic was collected with a neuston net (1.0-
0.5-m mouth, 200-m mesh) towed at 23 knots for periods 1015 min, total tows
225] were 3,070 samples from around the world. The concentration of plastic litter
ranged broadly, spanning over four orders of magnitude across the open ocean. The
distribution pattern agreed with those predicted from ocean surface circulation
models confirming the accumulation of plastic debris in the convergence zone of
each of the 5 large subtropical gyres. The scientific group estimated the amount of
plastic waste in the open-ocean surface between 7,000 and 35,000 tons. The plastic
load in the North Pacific Ocean could be related to the high human population on the
eastern coast of the Asian continent, the most densely populated coast in the world.
Examination of the size distribution of plastic debris on the ocean surface shows a
peak in abundance of fragments around 2 mm and a pronounced gap below 1 mm.
The scientists emphasized that the pathway and ultimate fate of the missing plastic
litter are as yet unknown and it is likely to involve a combination of multiple sinks.
They propose that missing microplastic may derive from nano-fragmentation
processes, rendering the very small pieces undetectable to convectional sampling
nets, and/or may be transferred to the ocean interior. The abundance of nano-scale
plastic particles has still not been quantified in the ocean and the measurements of
microplastic in deep ocean (sediments) are very scarce.108
A group of scientists (first author, Eriksen Marcus, co-founder of the 5 Gyres
Institute in the US) traveled in the South Pacific subtropical gyre (March-April 2011,
trip of 4,489 km) and took neuston samples (using a manta trawl lined with a 333 m
mesh) at 48 sites (averaging 50 nautical miles apart) in order to measure marine
pollution (especially plastic litter) in the open ocean of the southern hemisphere
which was largely undocumented until then. The results showed an increase in
surface abundance of plastic debris in the center of the gyre and a decrease as we
moved away, verifying the presence of a garbage patch. The average abundance
and mass was 26,898 particles.km2 and 70.96 g.km2, respectively. The study found
that 89% of the plastic pollution was found in the middle third of the samples with the
highest value occurring near the center of the predicted accumulation zone.109
Scientists in the last few years focused on oceanographic model predictions
of where debris (including plastic waste) might converge in the global oceanic
environment. Until now, estimates of regional and global abundance and weight of
27
floating plastics have been limited to microplastics. They used published survey data,
particularly from the Southern Hemisphere subtropical gyres and marine areas
adjacent to populated. The oceanographic model assumed that the amounts of
plastic entering the ocean depend on three principal variables: watershed outfalls,
population density and maritime activity. The dataset used in this model was based
on expeditions from 20072013 surveying all five sub-tropical gyres (North Pacific,
North Atlantic, South Pacific, South Atlantic, Indian Ocean) and extensive coastal
regions and enclosed seas (Bay of Bengal, Australian coasts and the Mediterranean
Sea). In a 2014 report scientists estimated accumulated all data and estimated the
total number of plastic particles and their weight floating in the world's oceans from
24 expeditions (20072013, 5 sub-tropical gyres, costal Australia, Bengal and the
Mediterranean Sea). Using an oceanographic model of floating debris dispersal
calibrated by all data, and correcting for wind-driven vertical mixing, they estimated a
minimum of 5.25 trillion particles weighing 268,940 tons. When comparing between
four size classes, two microplastic <4.75 mm and meso- and macroplastic >4.75 mm,
a tremendous loss of microplastics was observed from the sea surface compared to
expected rates of fragmentation, suggesting there are mechanisms at play that
remove <4.75 mm plastic particles from the ocean surface.110
Figure 18. The Eriksen et al. survey and modeling of plastic waste. Combining data
from 24 sampling missions with oceanographic computer modeling. Eriksen and
colleagues predicted the global distribution of plastic particles in specific size classes.
(Source:(2014) PLoS One http://dx.doi.org/10.1371/journal.pone.0111913.g002].110
Another recent study collected data on litter distribution and density
(especially plastic waste) collected during 588 video and trawl surveys across in 32
28
sites of European waters. In their publication, scientists focused on the fact that they
found litter to be present in the deepest areas of the sea and at some remote
locations. The highest litter density occured in submarine canyons, whilst the lowest
density was found on continental shelves and on ocean ridges. The study showed
that plastic waste (various items and sizes) was the most prevalent litter item found
on the seafloor. Litter from fishing activities (derelict fishing lines and nets) was
particularly common on seamounts, banks, mounds and ocean ridges.111
Figure 19. Ocean pollution by plastic waste is becoming a bigger problem each year.
When floating plastic litter gets in the ocean it usually ends up in one of the gyres.
[https://www.pinterest.com/pin/237564949064006320/?from_navigate=true ]
Other scientists emphasized the urgency to standardize common
methodologies to measure and quantify plastics in seawater and sediments and their
ecological consequences of widespread plastic pollution. An elevated number of
marine species is known to be affected by plastic contamination, and a more
integrated ecological risk assessment of these materials has become a research
priority. Microplastics and chemical additives are accumulated by planktonic and
invertebrate marine organisms and as a result are transferred along food chains.
Negative consequences include loss of nutritional value of diet, physical damages,
exposure to pathogens and transport of alien species. Because of plastic pollution
complex ecotoxicological effects are increasingly reported in scientific publications.112
A recent study (2015) (Marine Debris Working Group at the National Center
for Ecological Analysis and Synthesis, University of California, Santa Barbara, with
support from Ocean Conservancy) estimated the global standing stock of small
floating plastic debris (microplastics) with the most comprehensive dataset, ocean
models and ocean plastic input available. The scientific group compiled all available
plastic data collected with surface-trawling plankton nets (more than 11,000
29
observations, including the surveys on papers of et al 2014108 and Eriksen et
al 2014110), using a rigorous statistical model, and then used the standardized
dataset to scale the outputs of three ocean circulation models. The final report
estimated that the accumulated number of microplastic particles in 2014 ranges from
15 to 51 trillion particles, weighing between 93,000 and 236,000 metric tons, which is
only approximately 1% of global plastic waste estimated to enter the ocean in the
year 2010. According to the research group these estimates are larger than previous
global estimates, but vary widely because the scarcity of data in most of the world
oceans, differences in model formulations, and fundamental knowledge gaps in the
sources, transformations and fates of microplastics in the ocean.113,114
Figure 20. Most plastic debris collected in surface-towing plankton nets can be
classified as microplastics (smaller than 5 mm in size),
Another problem of plastic waste pollution in the oceans that drew the
attention of scientists was the potential for microplastics to sorb hydrophobic organic
chemicals (some of them highly toxic) which in turn to transfer to aquatic organisms.
Results of laboratory experiments and modeling studies indicate that hydrophobic
chemicals can partition from microplastics to organisms but little information is
available to evaluate ecological or human health effects from this exposure. Most of
the available studies measured biomarkers that are more indicative of exposure than
effects, and no studies showed effects to ecologically relevant endpoints. Therefore,
evidence is weak to support the occurrence of ecologically significant adverse effects
on aquatic life.115
30
Policies for the Reduction of Plastic Pollution in the Oceans
Marine pollution policies in many developed countries has change recently
due to the long-time threads of plastic marine debris. Existing policies for waste
management, especially plastic, marine debris monitoring and awareness campaigns
were evaluated in many developed countries and recommendations included
improved practices in law and waste management strategies; education, outreach
and awareness; source identification of marine pollution; and increased monitoring
and further research for microplastics, introduction of biodegradable plastics and
adverse effects on marine biota. In many countries established programs were
designed to remove macroplastics from beaches, waterfronts, and oceans despite
the gaps of scientific knowledge. A few global initiatives do exist on plastic
contamination, disposal, and pollution prevention. However, because plastic wastes
are globally persistent, development of both international and regional management
strategies are required to address the issue.116
The first action recommended at international meetings is the prevention of
pollution from ships aimed at preventing disposal of waste at sea. The International
Convention for the Prevention of Pollution of Ships (MARPOL) Annex V prevents
pollution of plastic waste by ships through international agreements and domestic
legislation. Some countries have their own domestic legislation (e.g. US Marine
Plastic Pollution Research and Control Act). Many ports across North America have
also adopted the Green Marine environmental program, requiring participants to
provide adequate reception facilities at ports for ship generated waste. Canada has a
framework policy to mitigate plastic marine pollution.117
The United Nations Environment Programme (UNEP) governs the Global
Programme of Action for the Protection of the Marine Environment from Land-Based
Activities, which provides a mechanism for development and implementation of
initiatives to address transboundary issues. Microplastic and other marine debris
issues are addressed by the same program. Additionally, UNEP collaborates with the
International Oceanographic Commission of the United Nations Educational,
Scientific, and Cultural Organization to develop guidelines to monitor marine litter. 118
The National Oceanic and Atmospheric Administration (NOAA) and UNEP developed
the UNEP Honolulu Strategy after the Fifth International Marine Debris Conference in
March 2011.119
The United States Environmental Protection Agency (USEPA) Marine Debris
Strategy, and the Global Partnership on Marine Litter (GPML) focuses on three main
31
objectives: land-based prevention, ocean assessment and cleanup, and land-based
reduction of marine debris.120 Also, many NGOs in various countries (Non-
Governmental Organizations) started many years ago to monitor marine debris
(especially plastic litter) and promote waste management education practices. The 5
Gyres institution focuses on impacts of plastic marine pollution in five subtropical
ocean gyres where plastic accumulates to investigate distribution of microplastics
and associated POPs. The Joint Group of Experts on the Scientific Aspects of Marine
Environmental Protection (GESAMP) advises for years
scientific aspects of marine environmental protection. Clean Seas Coalition (CSC,
environmentalists, scientists, lawmakers, etc) targets Californian seas and beaches,
including the North Pacific Gyre, for awareness of marine pollution. The International
Coastal Cleanup (ICC) is a movement guided by Ocean Conservancy that unites
volunteers around the world to clean up aquatic and marine environments and
provide recommendations for the state Ocean Protection Council [Clean Seas
Coalition, Clean Seas Coalition, [Available at http://cleanseascoalition.org/]
(accessed 16). The Ocean Conservancy is also a current founding member of the
ive forum focused on
identifying opportunities for cross-sector solutions for marine litter.121
European Union countries have advanced various environmental policies to
reduce plastic pollution of the oceans and recycling of plastic waste. Many European
nations have not only passed EPR (extended producer responsibility EPR, which
was first formally outlined in an internal Swedish government report in 1990). laws to
increase reuse and recycling of plastics. Many EU countries (Denmark, Sweden etc)
for many years are diverting plastics waste to power plants for use as fuel for heat
and electricity (a process called waste-to-energy, or WTE). In Europe, an estimated
25.2 million metric tons of post-consumer plastic was discarded in 2012, according to
the manufacturers association PlasticsEurope. From the plastic waste produced 26%
was recycled, 36% was recovered for fuel, and 38% went to landfills. Some EU
nations (9 from 28) have banned landfills for plastic waste and other domestic waste.
The plastic manufacturers, PlasticsEurope, recommended to the consumers for zero
plastic waste going to European landfills by 2020.122
MARLISCO is a European initiative, which developed and implemented
activities across 15 European countries, towards raising societal awareness and
engagement on marine litter, through a combination of approaches: public exhibitions
in over 80 locations; a video competition involving 2100 students; and a legacy of
educational and decision-supporting tools. 12 national participatory events designed
32
to facilitate dialogue on solutions brought together 1500 stakeholders and revealed
support for cross-cutting, preventive measures.123
The Mediterranean Information Office for Environment, Culture and
Sustainable Development (MIO-ECSDE, Athens, Greece), is the Federation of the
wider existing spectrum of environmental, cultural and development NGOs active in
the Mediterranean. MIO-ECSDE is active and cooperates in research and surveys on
plastic pollution in the marine environment, especially in the Mediterranean Sea.
Another interesting programme is Derelict Fishing Gear Project in the Adriatic
Sea (DeFishGear) is addressing wider context of the marine litter (among others, lost
and abandoned fishing nets, microplastics, etc in the Adriatic Sea) of issue to
ultimately provide a key strategic input on a regional level. The Adriatic region is
facing a big gap when it comes to marine litter analysis. It results in a lack of
appropriate mitigation measures aimed at reducing marine pollution evident in every
country of the region. MIO-ECSDE [http://mio-ecsde.org/] organized the conference
which took place in Athens, Greece in
February 2016. Also, MIO-ECSD participated in the Conference under the title "Fate
and Impact of Microplastics in Marine Ecosystems: From the Coastline to the Open
Sea" (Spain, from in May 2016). In the last few years the number of conferences in
Europe and in other continents on plastic waste, marine pollution, microplastics and
toxic effects on marine biota has increased substantially.
Conclusions
. Since plastic production began in the 1950s, plastic waste or litter or garbage,
has environment, especially in the marine
environment and the oceans. This is the result of our consumer society, massive
production of single use plastic packaging items and thrown away after use mentality.
The results are obvious today in the natural environment and the threat of plastic
debris on the marine environment were reviewed by numerous scientific studies and
international surveys. Today, scientists, consumers and environmentalists agree that
rigorous approaches are urgently required to mitigate the problem of plastic waste.
Unlike other materials (wood, paper, grass, metals) plastic are strong, non-
biodegradable and float in water. Weathering degradation of plastics items results in
their surface embrittlement and microcracking. Finally, after many years plastics are
breaking into small pieces, yielding microparticles (>1 mm), that are carried into
water by wind or wave action. Also, microplastics can concentrate persistent organic
33
pollutants (POPs) that can be ingested by marine biota. Bioavailability and the
efficiency of transfer of the ingested POPs across trophic levels are not known and
the potential damage posed to the marine ecosystem has yet to be quantified and
modelled. Recent studies showed that microplastics have been accumulating in the
oceans for at least over the last four decades. Plastic litter with a terrestrial source
contributes ∼80% of the plastics found in marine litter. Plastic litter has permeated
marine ecosystems across the globe and driven by ocean currents, winds, river
outflow and drift can be transported vast distances to remote, otherwise pristine,
locations (the poles, ocean gyres and ocean depths). Over the past decade,
increased scientific interest has produced an expanding knowledge base for
microplastics, but fundamental questions and issues remain unresolved. International
and national programmes have been initiated aiming to mitigate the spread of this
marine pollution with limited success.
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