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Leveraging Multi-Target Strategies to Address Plastic Pollution in the Context of an Already Stressed Ocean

Leveraging Multi-Target
Strategies to Address
Plastic Pollution in the
Context of an Already
Stressed Ocean
Jenna Jambeck, Ellie Moss and Brajesh Dubey
Zainal Arifin, Linda Godfrey, Britta Denise Hardesty, I. Gede Hendrawan, To
Thi Hien, Liu Junguo, Marty Matlock, Sabine Pahl, Karen Raubenheimer,
Martin Thiel, Richard Thompson and Lucy Woodall
Commissioned by
ii | High Level Panel for a Sustainable Ocean Economy
About this Paper
Established in September 2018, the High Level Panel for a Sustainable Ocean Economy (HLP) is a unique
initiative of 14 serving heads of government committed to catalysing bold, pragmatic solutions for ocean
health and wealth that support the UN Sustainable Development Goals and build a better future for people
and the planet. By working with governments, experts and stakeholders from around the world, the High Level
Panel aims to develop a roadmap for rapidly transitioning to a sustainable ocean economy and to trigger,
amplify and accelerate responsive action worldwide.
The HLP consists of the presidents or prime ministers of Australia, Canada, Chile, Fiji, Ghana, Indonesia,
Jamaica, Japan, Kenya, Mexico, Namibia, Norway, Palau and Portugal, and is supported by an Expert Group,
Advisory Network and Secretariat that assist with analytical work, communications and stakeholder
engagement. The Secretariat is based at World Resources Institute.
The HLP has commissioned a series of ‘Blue Papers’ to explore pressing challenges at the nexus of the ocean
and the economy. These papers summarise the latest science and state-of-the-art thinking about innovative
ocean solutions in the technology, policy, governance and finance realms that can help accelerate a move
into a more sustainable and prosperous relationship with the ocean. This paper is part of a series of 16 papers
to be published between November 2019 and October 2020. This paper examines the leakage of plastics and
other pollutants into the ocean and the resulting impacts on marine ecosystems, human health and the
economy. The paper comments on the kind of regenerative global industry that needs to be built, as well as
integrated solutions to reduce all pollutants to the ocean.
This Blue Paper is an independent input to the HLP process and does not represent the thinking of the HLP,
Sherpas or Secretariat.
Suggested Citation: Jambeck, J., E. Moss, B. Dubey et al. 2020. Leveraging Multi-Target Strategies to Address
Plastic Pollution in the Context of an Already Stressed Ocean. Washington DC: World Resources Institute. Available
online at:
Table of Contents
Foreword ..................................................................................1
Key Messages ............................................................................2
1. Introduction ............................................................................3
2. Sources of Ocean Pollution ..........................................................5
3. Impacts of Ocean Pollution on Ecosystems, Marine Life,
Human Health and Economies .....................................................21
4. Human Dimensions ................................................................39
5. Opportunities for Action .............................................................41
References ..............................................................................51
Acknowledgments ....................................................................63
About the Authors .....................................................................63
1 Leveraging Multi-Target Strategies to Address Plastic Pollution in the Context of an Already Stressed Ocean |
The High Level Panel for a Sustainable Ocean Economy (HLP) commissioned us, the co-chairs of the HLP Expert
Group (a global group of over 70 content experts), to organise and edit a series of ‘Blue Papers’ to explore pressing
challenges at the nexus of the ocean and the economy. The HLP identified 16 specific topics for which it sought
a synthesis of knowledge and opportunities for action. In response, we convened 16 teams of global content
experts. Each resulting Blue Paper was independently peer-reviewed and revised accordingly. The final Blue Papers
summarise the latest science and state-of-the-art thinking on how technology, policy, governance and finance can
be applied to help accelerate a more sustainable and prosperous relationship with the ocean, one that balances
production with protection to achieve prosperity for all, while mitigating climate change.
Each Blue Paper oers a robust scientific basis for the work of the HLP. Together, they provide the foundation for
an integrated report to be delivered to the HLP. In turn, the HLP plans to produce by the end of 2020 its own set of
politically endorsed statements and pledges or recommendations for action.
Historically, the ocean has been viewed as so vast and untouchable as to be capable of absorbing everything that
we discharge into it. It has become the ultimate sink for land-based pollution—the most recent and most visible
being solid plastic waste. Thankfully, we have seen a wave of action targeting plastic waste—with individuals shiing
their own behaviours and governments stepping up to put in place a variety of policy measures. This paper aims to
complete the picture on pollution in our ocean—by looking across four main sectors at the full extent of waste that is
currently being discharged into our ocean—and identifying a pathway to change the way we see our ocean and what
we put into it.
As co-chairs of the HLP Expert Group, we wish to warmly thank the authors, the reviewers and the Secretariat
at World Resources Institute for supporting this analysis. We thank the members of the HLP for their vision in
commissioning this analysis. We hope they and other parties act on the opportunities identified in this paper.
Hon. Jane Lubchenco, Ph.D.
Oregon State University
Professor Peter Haugan, Ph.D.
Institute of Marine Research, Norway
Hon. Mari Elka Pangestu, Ph.D.
University of Indonesia
2 | High Level Panel for a Sustainable Ocean Economy
Key Messages
Plastic is the newest pollutant to be entering the
ocean in significant quantities. It joins nonplastic
solid waste; nutrients; antibiotics, parasiticides and
other pharmaceuticals; heavy metals; industrial
chemicals including persistent organic pollutants;
pesticides; and oil and gas, each of which has a longer
history of scholarship and greater body of existing
research as an ocean pollutant than does plastic.
There are four major sources that discharge
pollutants into the ocean: municipal, agricultural
(including aquaculture), industrial and maritime.
These pollutants have damaging impacts on
ecosystems and marine life, human health and the
The presence of plastic in the ocean in growing
quantities is symptomatic of many societal challenges
that are relevant to the other pollutants and pollution
pathways: the lack of access to sanitation and
wastewater and stormwater processing for millions
of people around the world, the need for safe use
and disposal of chemicals, the development and
degradation of coastal zones, the need for an eicient
use of natural resources, and the need for improved
access to safe food and water.
This paper proposes seven holistic approaches for
the reduction of pollutants in the ocean: improve
wastewater management; improve stormwater
management; adopt green chemistry practices
and new materials; implement coastal zone
improvements; practice radical resource eiciency;
recover and recycle the materials we use; and build
local systems for safe food and water.
These seven approaches address the major sources
of pollution entering the ocean and contribute to
multiple United Nations Sustainable Development
Each of the approaches identified are cross-sectoral
and system-level in nature, making them perfect
candidates for delivery through public-private
partnerships, innovative financing arrangements and
leveraging capital from a range of sources.
To solve the pollution challenge we need to start
with the premise that there is no such thing as waste.
The Earth is a closed system and there is nowhere
for damaging pollution to go that won’t harm
ecosystems, plant and animal life and, ultimately,
human life.
Once we adopt a no-waste approach, our economy
will be very eective at finding the most eicient ways
to stop the problem of pollution
3 Leveraging Multi-Target Strategies to Address Plastic Pollution in the Context of an Already Stressed Ocean |
1. Introduction
The ocean is the ultimate sink for anthropogenic
pollution. According to the HydroSHED model, over
80 percent of the land mass on Earth is in a watershed
that drains directly to the ocean (Lehner and Grill 2013).
Until recently, the ocean seemed to be endlessly able to
absorb all the waste that human activity has discharged
into it. The Ocean Health Index (OHI) scores the health
of the ocean on a range of criteria, from how clean the
water is to the ability of the ocean to continue providing
services such as food provision, carbon storage, tourism
and recreation, and biodiversity (Halpern et al. 2012).
The 2019 combined global ocean score was 71 out of
100 (as it has been for the last five years), showing that
significant impairment has occurred, but that many
of the functions and services of the ocean remain and
must be better managed (OHI 2019). The Clean Water
section of the OHI includes details on the statuses and
pressures of chemical, nutrient, pathogen and trash
pollution. It also includes social pressure as a further
pressure. Indicators of resilience were based upon the
Convention on Biological Diversity (in particular for
marine ecosystems) and quality of governance (using
Worldwide Governance Indicators). The score for Clean
Water has tracked closely to the overall score, remaining
at 70 for the past five years (OHI 2019). With an estimated
91 percent of all temperate and tropical coasts predicted
to be heavily developed by 2050 (Nellemann et al. 2008),
this is a critical time to significantly reduce and prevent
anthropogenic pollution to the ocean.
Pollutants enter the ocean in four ways: They may be
discharged directly into the ocean, discharged into
rivers which flow to the ocean, washed from land by
stormwater into rivers or directly into the ocean or
deposited from the air onto land to be washed into
waterways or directly into the ocean.
There are many anthropogenic sources of pollution,
and this paper focuses on pollution inputs to the ocean
from four sectors: municipal, agricultural, industrial
and maritime. This paper focuses first on plastic, as
the newest and least well understood pollutant, and
puts plastic pollution in the context of an ocean already
receiving significant pollution from nutrients, heavy
metals, persistent organic pollutants (POPs), pesticides
and oil.
While successful implementation of all the United
Nations (UN) Sustainable Development Goals (SDGs)
would help protect the ocean, SDG 14: Life Below Water
is the primary SDG directly related to the ocean. But
there are several other SDGs that are very relevant to
pollution reaching the ocean: SDG 2: Zero Hunger, SDG
3: Good Health and Well-Being, SDG 6: Clean Water and
Sanitation, SDG 8: Decent Work and Economic Growth,
SDG 9: Industrial Innovation and Infrastructure, SDG
11: Sustainable Cities and Communities and SDG 12:
Responsible Consumption and Production.
Plastic is the newest pollutant to be entering the
ocean in significant quantities. It joins nonplastic solid
waste; nutrients (nitrogen, phosphorous); antibiotics,
parasiticides and other pharmaceuticals; heavy metals;
industrial chemicals including persistent organic
pollutants; pesticides; and oil and gas, each of which
has a longer history of scholarship and greater body of
existing research as an ocean pollutant than does plastic.
This paper seeks to put ocean pollution from plastic into
the context of total pollutant inputs to the ocean and
identify the interventions that can have the greatest total
impact on all pollution to the ocean, capitalising on the
current global attention on plastic pollution.
In this Blue Paper, four major sectors that create
pollutants are explored—municipal, agricultural
(including aquaculture), industrial and maritime—and
three types of impacts are characterised—ecosystems
and marine life, human health and economic. The
impacts on ecosystems include harm to marine life
from ingestion of and entanglement from plastic,
eutrophication and hypoxia, and biomagnification
of chemicals. The human health impacts from direct
or indirect exposure to these pollutants include
reproductive, developmental, behavioural, neurologic,
4 | High Level Panel for a Sustainable Ocean Economy
endocrine and immunologic adverse health eects;
acute or chronic toxicity; cancer; increased exposure
to pathogens and mosquito-borne diseases; and risk of
entanglement or entrapment. The economic impacts
come from impaired productivity of fisheries, loss of
seafood supply resulting from toxicity and reduced
tourism and recreation in coastal areas.
The presence of plastic in the ocean in growing
quantities is one symptom of a set of societal challenges
that are also relevant to the other pollutants and
pollution pathways: the lack of access to sanitation and
wastewater and stormwater processing for millions
of people around the world; the need for safe use and
disposal of chemicals; the development and degradation
of coastal zones; the need for an eicient use of natural
resources; and the need for improved access to safe food
and water.
At the heart of these challenges is recognising that the
notion that things can be thrown away is a myth—there
is no ‘away’ where pollutants can safely go.
This paper proposes seven intervention approaches
that lead with reducing plastic inputs to the ocean but
also seek to maximise the reduction of other pollutants
as co-benefits. Four types of actions were considered:
innovation, infrastructure, policy and mindset. Specific
actions of each type were identified across the sectors
and pollutants described in the report. These actions
were then bundled into the following seven holistic
opportunities for action (not in ranked order):
1. Improve wastewater management
2. Improve stormwater management
3. Adopt green chemistry practices and new materials
4. Implement coastal zone improvements
5. Practice radical resource eiciency
6. Recover and recycle the materials we use
7. Build local systems for safe food and water
These seven opportunities for action address the
major sources of pollution entering the ocean, and
contribute to achieving the United Nations Sustainable
Development Goals (SDGs). They would directly
influence SDG targets 2.1, 2.3, 3.9, 6.1, 6.2, 6.3, 6.B, 8.3,
11.6, 12.2, 12.4, 12.5 and 14.1 and indirectly influence a
number of others, such as through expanded economic
opportunities, benefits to people’s livelihoods and
increased well-being. The cross-sector, system-level
nature of these challenges makes them perfect
candidates for public-private partnerships, innovative
financing arrangements and leveraging capital from a
range of sources.
Finally, while the body of research on plastic is growing
rapidly, there remain significant data gaps both on
inputs and impacts. More research is needed to better
understand and document the scope and scale of plastic
pollution, as well as its impacts on ecosystem and
human health. Given the global nature of the problem,
open data protocols that can facilitate the aggregation
and sharing of compatible data are critical.
5 Leveraging Multi-Target Strategies to Address Plastic Pollution in the Context of an Already Stressed Ocean |
Figure 1. Sources of Ocean Pollution
Oil Platforms &
Oil Spills Aquaculture Recreational
Disaster Debris
Industrial &
Pharmaceutical &
Power Stations
Treatment Plants &
Crop & Animal
Vehicle Wear & Tear,
Road Runoff and
Air Emissions
Solid Waste
(Plastics, Dumping,
Leakage from Waste
Source: Graphic developed by K. Youngblood
2. Sources of Ocean Pollution
This paper includes pollution inputs from land and
sea, grouped into four sectors: municipal, agricultural,
industrial and maritime.
Municipal sources are residential and commercial solid
waste and wastewater as well as runo from roads and
landscaping activities. Additionally, debris entering the
ocean as a result of natural disasters is included here.
Land-based agricultural activities impacting the ocean
include plastic, pesticide and nutrient use as well as
waste management for animal agriculture. Ocean-based
aquaculture’s pollution impacts include the use of
antibiotics and parasiticides, antifoulants containing
heavy metals, loss of equipment and management of
fish waste.
The industrial sector includes manufacturing,
mining and energy production. Pollutants coming
from this sector include plastic pellets and waste,
other solid waste, dredge spoils, industrial chemicals
including POPs, heavy metals, pharmaceuticals and
pharmaceutical waste products, and oil and gas.
Maritime pollution comes from the shipping, cruise
and fishing industries and from recreational boating.
Pollution from these sources includes litter, food waste,
sewage and accident debris.
Figure 1 shows the primary sources of pollution in
the marine environment from these sectors. Table 1
summarises the types of pollution entering the
ocean and the ways that each sector contributes
to ocean pollution.
6 | High Level Panel for a Sustainable Ocean Economy
Microplastics (<5
millimetres [mm])a
Microbeads, microfibres,
tire dust, fragments in
runo from land
Slow release fertiliser
pellets, plastic mulch
Industrial pellets Pellets lost at sea in shipping
accidents, dredged materials
and breakdown of other
wastes dumped at seab
(>5 mm)a
Unmanaged plastic waste
within 50 kilometres (km)
of river or ocean1
Aquaculture infrastruc-
ture and equipment,
greenhouses, plastic
sheeting and associated
Unknown Fishing gear, lines and
lures; litter from ships and
boats; debris from shipping
Other solid waste Unmanaged solid waste
within 50 km of river or
ocean, disaster debris,
wood, food waste dumpingc
Lost/unmanaged aqua-
culture infrastructure
and equipment, manure
and biosolids land
Dredge spoils Fishing gear, litter from ships
and boats, debris from ship-
ping accidents, food waste
discharge from ships
Pesticides2Residential and commercial
landscaping and gardening
Crop-based agriculture Minimal Minimal
Nutrients (N, P) Untreated municipal
wastewater, residential and
commercial landscaping
and gardening, airborne
nitrogen from vehicle ex-
haust deposition into ocean
Crop-based agriculture,
lagoon leakage, aqua-
culture fish waste
Airborne nitrogen
from energy produc-
tion deposition into
Sewage discharges
into ocean
parasiticides, other
Treated and untreated
culture, land-based
animal agricultural
production waste-
Treated and untreated
wastewater from ships
Heavy metals Urban runo: copper,
chromium, nickel;
mismanaged electronic
ture: arsenic, mercury,
cadmium, lead
Mining manufacturing:
copper, zinc, lead,
cadmium, chromi-
um, nickel, arsenic,
Paints and pigments: zinc,
tributyltin, lead, cadmium
Industrial chemicals
and persistent
organic pollutantsc
Treated and untreated
wastewater, urban runo
Use of organochlorine
Regulated and unreg-
ulated discharge from
Treated and untreated
wastewater from ships
Oil and gas Urban runo Accidental discharge
from agricultural
equipment use and
Spills, water contami-
nation, and improper
disposal from oil
refineries and logistics
(pipelines, rail, trucks)
Drilling rigs, bilge water and
fuel release, tanker spills,
Notes: Table 1 notes shown on page 7.
Notes: Table 1 notes shown on page 7.
Table 1. Sources of Pollutant Discharges into the Ocean
7 Leveraging Multi-Target Strategies to Address Plastic Pollution in the Context of an Already Stressed Ocean |
Other than specific pollutants regulated by international
treaties in certain situations—e.g. International
Convention for the Prevention of Pollution from
Ships (MARPOL) for plastic discharges; Stockholm
Convention for specific chemicals; Basel Convention
for waste exportation; London Convention and Protocol
for ocean dumping—and acts that have regulated
discharge nationally and locally—e.g. total maximum
daily loads under the Clean Water Act in the United
States—pollutants continue to enter the ocean without
consistent and global limits or regulation.
Past emissions of ocean pollution remain relevant today,
especially in the case of persistent pollutants such as
plastics, heavy metals and POPs, as they remain in
the ocean interacting with each other and the marine
environment. For example, while 28 POPs are banned
or restricted and have been for a number of years (12
since 2004, 16 since 2010), they are readily absorbed by
plastic in the ocean, which creates a new mechanism for
them to interact with the marine ecosystem (Rochman
et al. 2013; Rochman et al. 2014b; Rochman 2015). Heavy
metals have also been found to adhere to plastic in the
ocean as biofilms accumulate on its surface (Rochman et
al. 2014a; Richard et al. 2019).
It should be noted that the ocean is also subject to
other forms of pollution, including acidification (see
Blue Paper 2, Gaines et al. 2019) and other nonphysical
forms like thermal, noise and biological pollution.
Thermal pollution is a change in temperature in the
ocean water from discharges, oen warmer water from
powerplant cooling, that can change both physical
and chemical properties of the ocean, impacting, for
example, bivalves since they are stationary (Dong et
al. 2018). Noise pollution in the ocean from shipping,
oil and gas exploration and military activities can also
impact marine life (Francis and Barber 2013). The
International Whaling Commission and Convention
on Biological Diversity have groups working on noise
pollution. Biological pollution is the transfer of, for
example, invasive species, which has been exacerbated
by evolving habitats due to climate change and ocean
acidification (Miranda et al. 2019), topics covered in Blue
Paper 2 (Gaines et al. 2019). The transport of invasive
species by plastic is covered in this paper. While these
other pollution sources are out of scope for this paper,
it is worth noting them here as they underscore the high
number of stressors that ocean ecosystems are facing.
2.1 Plastic Pollution
Plastic is a material that has permanently changed our
world since its introduction into mainstream society (in
some countries) aer World War II; global annual plastic
production has increased from 1.7 million metric tons
per year (MMT/yr) in 1950 to 422 MMT/yr in 2018 (Geyer
et al. 2017; PlasticsEurope 2019). Along with a steep
increase in production, we have seen a resulting increase
in plastic in the waste stream from 0.4 percent in 1960
to 13.2 percent in 2017 (by mass) in the United States
(EPA 2014; EPA 2019). In 1966, two U.S. Fish and Wildlife
Service employees, Karl W. Kenyon and Eugene Kridler,
were among the first scientists to document plastic and
wildlife interactions when they discovered plastic had
been consumed by seabird (albatross) chicks that died
in the Hawaiian Islands National Wildlife Refuge (Kenyon
and Kridler 1969). Since then, analysing plastic material
Table includes both point source (e.g. specific discharge points) and nonpoint source (e.g. stormwater runo) forms of pollution.
a. Macroplastics are any plastics larger than 5 mm. Microplastics are small pieces or fragments of plastic smaller than 5 mm (Galgani et al. 2010;
SAPEA 2019).
b. Wastes allowed to be dumped at sea according to the London Convention and Protocol include dredged materials; sewage sludge; fish waste,
or material resulting from industrial fish processing operations; vessels and platforms or other man-made structures at sea; inert or inorganic
geological material; organic matter of natural origin; bulky items comprising primarily iron, steel, concrete or non-harmful materials; and carbon
dioxide streams from carbon dioxide capture processes for sequestration.
c. Jambeck et al. 2015.
d. Persistent organic pollutants are organic compounds that are resistant to environmental degradation through chemical, biological and photolytic
processes. They include polybrominated diphenyl ethers (PBDEs), per- and polyfluoroalkyl substances (PFASs), polychlorinated biphenyls (PCBs)
and organochlorine (OC) pesticides.
1. Jambeck et al. 2015.
2. Weibel et al. 1966.
8 | High Level Panel for a Sustainable Ocean Economy
in 2004 (Thompson et al. 2004) and the identification of
microplastics is a relatively new field (Shim et al. 2017),
with nanoscale plastics (not even yet formally defined)
especially challenging to identify because of limits to
the capabilities of the current instrumentation used for
environmental samples. As a consequence, quantifying
inputs has been challenging (Koelmans et al. 2015; Rist
and Hartmann 2017; SAPEA and Academies 2019).
As of 2017, 8 billion metric tons of plastic had been
produced for human use. Because a large quantity was
used for packaging (about 40 percent) and single-use
items, 6.4 billion metric tons had already become waste
by 2015 (Geyer et al. 2017). Many packaging and single-
use materials are composed of polyethylene
(high and low density, HDPE and LDPE), polypropylene
and polyethylene terephthalate (PET). These polymers
are oen the materials used in the most common
items found littering the environment, especially on
coastlines: cigarette butts, plastic bottles, plastic food
wrappers, straws, plastic bags and bottle caps (Ocean
Conservancy 2018).
The total quantity of plastic entering the ocean every
year is still unknown. While there have been estimates
of some sources (e.g. municipal waste), there are more
sources that do not have current estimates. While
many scientists would agree that a large portion of
mismanaged plastic comes from land, even the 80
percent from land is a questionable statistic since the
true total from all sources remains unknown. Some
of the sources have been quantified. Jambeck et al.
(2015) found that the annual input from mismanaged
solid waste on land (one of the major sources) in 2010
was between 4.8 and 12.7 MMT/yr. Other estimates
have come from riverine input and other geographic
information system (GIS) analyses, which have found
that from 0.41 to 4 MMT of plastic is entering the ocean
every year from rivers (a subset of the total quantity
entering the ocean) (Lebreton et al. 2017; Schmidt et
al. 2017). Up to 99 MMT of mismanaged plastic waste
has been estimated to be available to enter waterways
around the world (Lebreton and Andrady 2019). The
estimate of 8 MMT as a middle estimate for input to the
ocean (Jambeck et al. 2015) remains the most widely
used value for land-based input of plastic waste into the
ocean, although this is likely conservative. Forrest et al.
(2019) built on the existing research by incorporating
flows (especially the waste streams), contamination
in our environment and the economics of the material
has become a recognised scientific discipline, with
rapid increases in the science, especially in the last
five years (Beaumont et al. 2019). But as a relevantly
young scientific discipline, there are still many gaps in
knowledge and a lack of information for solutions to
plastic pollution (Bucci et al. 2019; Forrest et al. 2019).
Even with knowledge gaps, plastic pollution has quickly
become one of the most salient topics of late—people
around the world passionately
care about and want to address
this issue.
2.1.1 Municipal plastic
Plastic pollution is oen
subdivided into macroplastics
and microplastics (e.g. the
U.S. National Oceanic and
Atmospheric Administration
uses this division), and
although there is much
discussion internationally
about terminology (GESAMP
2015), these size categories
are currently used extensively
around the world. Macroplastics
are any plastics larger than
5 millimetres (mm) and can
include both short-use items (e.g.
food packaging and foodservice
disposables) and longer-use
items (e.g. flip flops, printer
cartridges, synthetic textiles).
Microplastics are small pieces
or fragments of plastic less
than 5 mm (Galgani et al. 2010;
SAPEA and Academies 2019)
that enter the environment as
a consequence of either the
direct release of small particles such as microbeads from
cosmetic products; the fragmentation of larger items
of litter in the environment; or the wear or abrasion of
products during use, such as the release of fibres from
textiles or particles from car tires (Law and Thompson
2014). The term microplastic was first used in this context
As of 2017,
8 billion metric
tons of plastic
had been
produced for
human use.
Because a
large quantity
was used for
packaging (about
40 percent) and
single-use items,
6.4 billion metric
tons had already
become waste
by 2015.
9 Leveraging Multi-Target Strategies to Address Plastic Pollution in the Context of an Already Stressed Ocean |
additional estimates of plastic waste flows to the ocean
arising from imported waste by developing countries
from wealthier consumer economies. This export/import
imbalance was initially outlined in (Brooks et al. 2018),
which describes the plastic import ban, more commonly
known as the National Sword policy, imposed by China
and its impacts on global plastic scrap trade. Forrest et
al. (2019) estimated current plastic flows to the ocean
from all sources to be at least 15 MMT/yr.
There are at least two more global baseline estimates
in the process of being calculated for plastic, one
by a working group through the National Socio-
Environmental Synthesis Center funded by the U.S.
National Science Foundation and one through The
Pew Charitable Trusts and SYSTEMIQ, which, while not
available before publishing this document, will make
it possible to measure the impacts of interventions at
the global and country levels, similar to the wedges
approach developed for climate change (Pacala and
Socolow 2004). Clearly topography and proximity
to the ocean are relevant for land-based or riverine
plastic, but some of the biggest data gaps in modelling
and measuring quantities entering the ocean exist for
these pathways. The most credible current estimates
nonetheless indicate that the quantities of plastic
entering the ocean are significant. The only regulatory
limits on plastic concentrations in the ocean are the total
maximum daily load limits in aquatic systems in the
United States (Smith 2000; DoE 2010), the Convention
on the Prevention of Marine Pollution by Dumping of
Wastes and Other Matter 1972 (the ‘London Convention’
for short, and then later the ‘London Protocol’ upon its
revision in 1996) (International Maritime Organization
2019), and MARPOL Annex V, all of which have zero
tolerance for plastic pollution.
2.1.2 Agricultural plastic pollution
Land-based agricultural plastic use typically includes
greenhouse or hoop house sheeting, netting, plastic
mulch (film), irrigation tape and piping, agrochemical
containers, silage, fertiliser bags and slow release
fertiliser pellets. The best current estimate of agricultural
plastic usage extrapolates from the European Union’s
(EU’s) demand for agricultural plastics of 1.6 million
tons annually to place world demand at approximately
8–10 million tons in 2015 (Cassou et al. 2018). A separate
calculation projected that the global agricultural film
market would reach 7.4 million tons in 2019 (Sintim
and Flury 2017). At the end of the growing season,
plastic mulch should be recovered from fields but this
is diicult because it shreds easily, so it is common
practice to till plastic mulch into the soil (Steinmetz
et al. 2016). Depending on the proximity to the ocean
or ocean-bound waterways, this improper end-of-life
management of the mulch could contribute to inputs of
plastic, especially microplastic, into the ocean.
Aquaculture also contributes significantly to marine
plastic pollution. Several studies have reported
abandoned, lost and discarded aquaculture gear in
coastal waters or on shores (Heo et al. 2013; Liu et al.
2013; Hong et al. 2014). Near aquaculture centres,
beaches oen contain large amounts of lost or discarded
plastic materials (Fujieda and Sasaki 2005; Hinojosa and
Thiel 2009; Andréfouët et al. 2014; Jang et al. 2014b;
Bendell 2015). Lost aquaculture gear that is floating
at the sea surface can also be transported over long
distances, potentially bringing non-native species to
other ecoregions (Astudillo et al. 2009). One of the few
studies that has estimated the losses from aquaculture
activities and their contribution to marine plastic
debris has been conducted in South Korea (Jang et al.
2014b). The authors showed that lost aquaculture gear
contributes a significant amount of plastic litter (mostly
expanded polystyrene, or EPS) in the coastal waters of
South Korea.
2.1.3 Industrial plastic pollution
Plastic resin pellets, the raw material from which
plastic items are made, continue to leak into the ocean
despite voluntary industry campaigns like Operation
Clean Sweep that encourage secure handling of the
pellets. Pellet pollution in the ocean has been further
documented because they are used to study POPs
and bacteria as well (Heskett et al. 2012; Rodrigues
et al. 2019). While quantities of inputs have not been
published on a global scale, one case study quantified
inputs from a facility along the west coast of Sweden
(Karlsson et al. 2018). While most of the pellet pollution
was reported to be localised, 3 to 36 million pellets
(above 300 micrometres) were estimated to enter the
waterways surrounding the production facility annually.
Karlsson et al. (2018) also stated that while there are
regulatory frameworks that can be applied to reduce
10 | High Level Panel for a Sustainable Ocean Economy
this pollution, they are not being eectively applied
or enforced. Lechner and Ramler (2015) found that
the regulations in Austria still allowed a production
facility to legally discharge 200 grams of pellets per
day and up to 200 kilograms (kg) during a high rainfall
event. An important legal precedent was just set in the
United States with Formosa Plastics agreeing to pay
a US$50 million settlement for a lawsuit against them
for discharging resin pellets into Lavaca Bay and other
nearby waterways (Collier 2019). Besides paying the
settlement, it has to adhere to a ‘zero discharge’ policy
moving forward with fines that increase over time for any
future discharges (Collier 2019).
2.1.4 Maritime plastic pollution
Fisheries activities contribute to pollution through
the accidental or intentional discarding of nets, ropes,
buoys, lines and other equipment, also known as
‘abandoned, lost or otherwise discarded fishing gear’
(ALDFG) (see Box 3 for a discussion of aquaculture).
Historic fishing nets were made from biodegradable,
locally sourced natural materials like cotton, flax or
hemp, but as materials like nylon and other polymers
were introduced, fishing practices (and eiciencies)
were increased, as early as 1951 in the United States and
Canada (Pycha 1962). United Nations General Assembly
and United Nations Environment Assembly resolutions
(2014, 2016, 2017) have addressed ALDFG, encouraging
the reduction of impacts from this marine debris that
is designed to capture and kill marine animals (Gilman
2015; Gilman et al. 2016). The Food and Agriculture
Organization of the United Nations’ (FAO’s) Committee
on Fisheries, the FAO Code of Conduct for Responsible
Fisheries and the FAO’s Voluntary Guidelines for the
Marking of Fishing Gear have also presented on marking
fishing gear and ALDFG reporting and recovery (Gilman
et al. 2016). Richardson et al. (2019) reviewed 68
publications from 1975 to 2017 that contain quantitative
information about fishing gear losses and found that
at an annual rate, all net studies reported gear loss
rates from 0 percent to 79.8 percent, all trap studies
reported loss rates from 0 percent to 88 percent, and all
line studies reported loss rates from 0.1 percent to 79.2
percent. Based upon this review, Richardson et al. (2019)
performed a meta-analysis estimating global fishing gear
losses for major gear types, finding that 5.7 percent of all
fishing nets, 8.6 percent of all traps, and 29 percent of all
lines are lost around the world each year. Abandoned,
lost or discarded fishing gear can ensnare or entangle
marine wildlife, have economic consequences due to
losses of commercially important food fish and can
smother sensitive coral reef ecosystems (Macfadyen et
al. 2009; Gunn et al. 2010; Wilcox et al. 2013; Richardson
et al. 2018). Commercial shipping and discharge from
ocean-going vessels result in plastic inputs through
accidental releases of cargo during ocean transit, which
may occur during rough weather or when containers are
insuiciently secured during transport (World Shipping
Council 2017).
11 Leveraging Multi-Target Strategies to Address Plastic Pollution in the Context of an Already Stressed Ocean |
Box 1. Spotlight on
Africa’s Current and
Future Rapid Growth
Africa’s contribution to waste
generation is currently low by global
standards.a However, the continent
is set to undergo a major social and
economic transformation over the
coming century as its population
explodes, cities urbanise and
consumer purchasing habits change.b
These changes will lead to significant
growth in waste and wastewater
generation, including nutrient exports
to coastal waters,c with sub-Saharan
Africa forecast to become the
dominant region globally in terms of
municipal solid waste generation.d This
will put significant strain on already
constrained public and private sector
services and infrastructure.e
As noted by Yasin et al. (2010) and
UNEP (2018a), there are limited
reliable, geographically comprehensive
waste and water quality data for Africa.
This makes it extremely diicult to
assess the potential impacts of waste
and wastewater systems locally and
regionally. However, anthropogenic
sources of nutrients in rivers, including
agricultural sources and human
sewage (oen untreated) from urban
centres, will become more important
than natural sources in large parts of
Africa.f Furthermore, with growing
population comes increased waste
generation and changing waste
types.g As such, in the absence of
reliable waste and water quality data,
population growth and economic
development can provide signals of
potential ‘geographic areas of concern’
with regard to plastic, industrial,
agricultural and municipal wastes.
According to the United Nations’
Department of Economic and Social
Aairs, more than half of the world’s
projected population growth between
2017 and 2050 is expected to come
from only 10 countries, with 6 of these
in Africa—Nigeria, the Democratic
Republic of the Congo, Ethiopia,
Tanzania, Uganda and Egypt (ordered
by their expected contribution to
global growth).h
Where the impacts of plastic and
nutrients on coastal systems in Africa
have been modelled, the models
have forecasted significant growth
in waste generation and potential
impact.i Tonnages of mismanaged
plastic waste is expected to increase
significantly between 2010 and 2025,
particularly in coastal countries such
as Nigeria, Egypt, Algeria, South Africa,
Morocco and Senegal (ordered by their
forecasted 2025 mismanaged plastic).j
The nutrient risk for large marine
ecosystems forecast for 2050 shows
very high coastal eutrophication risk
o the coast of West Africa around the
Gulf of Guinea.k
While waste volumes produced in
Africa are currently low, waste is
impacting the environment due to a
number of factors, including limited
environmental regulation and oen
weak enforcement, inadequate waste
and wastewater systems and the
transport of waste into Africa, oen
from developed countries.l With
an average municipal solid waste
collection rate of only 55 percent for
Africa,m the potential for plastic to leak
into the environment is high. There
is growing citizen and government
concern around the leakage of
plastic waste into the environment,
resulting in many African countries
moving to ban single-use plastics
as a way of limiting their negative
impacts. According to UNEP (2018b),
29 countries in Africa, predominantly
coastal countries, have already
implemented some sort of regulation
against plastics. Currently, these
regulations vary from a ban on single-
use (thin) plastic bags, with associated
requirements for bag thickness, to
a complete ban on all plastic carrier
bags. However, the growing concern
around plastic waste is sparking
discussions in many African countries
on possible further bans on other
single-use plastic products, such as
PET beverage bottles and food service
industry products such as straws, cups,
containers and utensils.
There is, however, a growing response
from a number of brand owners,
retailers and convertors to address
the current waste problems in Africa.
South Africa, for example, has had
voluntary industry initiatives in place
for over a decade aimed at growing
the local plastic recycling industry.
Initiatives such as the South African
PET Recycling Company, which has
achieved a 65 percent post-consumer
PET bottle recycling rate in South
Africa,n are now being rolled out in
Kenya, with plans to launch in Ethiopia
and Uganda.o There are also a number
of social innovations emerging in Africa
to deal with the plastic waste problem.
These oen focus on innovative
community-driven collection systems
and associated financial rewards
for recyclables, such as Wecyclers
in Nigeria and Packa-ching in South
a. Kaza et al. 2018.
b. African Development Bank 2012; UNDESA
2015a; UNDESA2015b.
c. Yasin et al. 2010; UNEP 2015.
d. Hoornweg et al. 2015.
e. UNEP 2015.
f. Yasmin et al. 2010.
g. UNEP 2015.
h. UN 2017.
i. Jambeck et al. 2017; UNEP 2018a.
j. Jambeck et al. 2015.
k. Seitzinger and Mayorga 2016.
l. Brooks et al. 2018; UNEP 2018a.
m. UNEP 2018a.
n. PETCO 2018.
o. Coca Cola 2019.
12 | High Level Panel for a Sustainable Ocean Economy
2.2 Other Pollutants
Compounding Ocean Stress
Pollution in this category stems from anthropogenic
development (including in rural and urban areas).
Municipal sources of pollution can be especially
high where population densities are high. Lack of
infrastructure that can handle sanitation and waste
management in rapidly growing cities, especially near
the coasts, is a large source of ocean pollution. Sources
in this sector include residential and commercial solid
waste and wastewater as well as runo from roads and
landscaping activities. Additionally, debris entering the
ocean as a result of natural disasters is included here.
2.2.1 Other municipal solid waste
The World Bank estimates that 2 billion metric tons of
municipal waste are generated globally with 33 percent
(663.3 MMT) being managed by ‘open dumping’ (Kaza et
al. 2018). Approximately 50 percent or more of this waste
is organic waste (e.g. food waste) in many places except
for Europe and North America, which generate around
30 percent organic waste. In high-income countries
(as ranked by the World Bank), 51 percent of the waste
stream is plastic, paper, cardboard, metal and glass,
while in low-income countries, only 16 percent of the
waste stream is estimated to be dry waste and able to
be recycled (Kaza et al. 2018). These statistics do not
even include special waste materials like medical and
electronic waste (e-waste), which pose even further
management challenges beyond municipal waste. While
regulated by the Basel Convention in international trade,
e-waste continues to be processed in areas without
adequate infrastructure or protection for workers;
to access the metal, the plastic housing and coatings
on wires are oen burned, releasing toxic emissions
impacting ecosystems and human health (Asante et
al. 2019).
Box 2. Waste
Management in Indonesia
The Indonesian government, through
President Act No. 83 in 2018 regarding
marine debris management, has
committed to reducing plastic waste
up to 70 percent by 2025.a To support
this eort, the Coordinating Ministry of
Maritime and Investment Aairs plans
to build a protocol to collect marine
debris data from several big cities in
Indonesia, including Banjarmasin,
Balikpapan, Bogor and Denpasar, and
has taken action through the Mayor Act
(Peraturan Wali Kota) and Governor Act
(Peraturan Gubernur) to regulate the
reduction of single-use plastic. While
some regulations regarding waste
reduction, segregation, collection
and transport already existed, the
lack of enforcement has caused
them to be poorly implemented.
To amplify eorts to reduce plastic
waste, the national government has
also constructed a cross-government
collaboration approach through a
National Plan of Action (Rencana Aksi
Nasional) on marine plastic debris for
2018–2025, which includes five main
actions: change behaviour, reduce
land-based leakage, reduce sea-based
leakage, enhance law enforcement
and financial support, and increase
research and development.b
In addition to regulatory solutions,
some villages are setting up their own
waste management facilities. In 2018,
Muncar, a small village in East Java,
worked with a private organisation
named SYSTEMIQ on a pilot project
called Project STOP, which, if
successful, can be implemented in
other villages throughout Indonesia.
For this project, they built a waste
management system in the area
that focuses on waste segregation
in households and capacity building
through a sorting centre. The
plan has five strategies, including
optimised waste collection, behaviour
change, regulation setting, village
waste management, institutional
capacity building and optimised
waste processing for both inorganic
and organic waste. In December
2019, 47,500 people received waste
collection, mostly for the first time,
from two facilities established by the
project. These facilities have collected
3,000 tons of waste so far and employ
80 local people.c
Indonesia is also looking for
alternatives to landfills for plastic
waste that cannot be recycled. One
option being investigated is a plastic
road tar that uses plastic waste,
mainly LDPE and HDPE. The plastics
are shredded, melted and added into
road-tar mix. In 2017, this method
was piloted at Udayana University,
Bali, where they laid a 700-metre-long
plastic road. However, an evaluation
hasn’t yet been done assessing the
potential for contamination into the
a. Purba et al. 2019.
b. Coordinating Ministry for Maritime Aairs
c. National Geographic 2020.
13 Leveraging Multi-Target Strategies to Address Plastic Pollution in the Context of an Already Stressed Ocean |
Another contribution beyond municipal waste is disaster
debris. With climate change increasing both the intensity
and frequency of storms around the globe, this pollution
input may increase in the future. One quantified example
of disaster debris originated from the 2011 Japanese
tsunami that washed out 3.6 MMT of debris, with 0.91
MMT floating across the Pacific Ocean and portions
of it reaching the western shores of North America
(NOAA 2013).
2.2.2 Pesticide pollution
Municipal pesticide pollution has been recognised in
nonpoint source stormwater runo since the 1960s
(Weibel et al. 1966). It is sourced from use in commercial
and residential landscaping and wastewater (Sutton et
al. 2019). Pesticide use and pollution can be significant
in densely populated areas where use is common, but
it is oen on a smaller scale compared with agriculture
use. One study of the Marne River in France determined
that urban uses of pesticides were considerably lower
(47 tons/yr) than agricultural ones (4,300 tons/yr)
(Blanchoud et al. 2007), with similar trends observed
in eight urban streams in the United States (Homan
et al. 2000).
Agricultural pesticides represent a category of human-
made or human-appropriated chemicals that are used
to prevent, destroy, repel or mitigate any pest, or as a
plant regulator, defoliant or desiccant (U.S. Code 1947).
Pesticides are categorised based on the target class
of organisms they are designed to impact. The most
common categories include herbicides, insecticides,
fungicides, rodenticides, algaecides and antimicrobials.
The ocean is exposed to pesticides through air, water,
soil and biota. The air transports pesticides globally,
documented as early as 1968 (Risebrough et al. 1968;
Seba and Prospero 1971), and has resulted in detectable
levels of pesticides in every part of the biosphere,
including in arctic ice (Pućko et al. 2017; Rimondino
et al. 2018). Pesticide transport through surface runo
occurs in both the liquid phase, where the pesticide
is solubilised in the runo water, and the solid phase,
where the pesticide is bound with soil particles that
erode with surface runo. Both mechanisms transport
pesticides from their application sites to the ocean. More
areas are likely to face high pesticide pollution risk as
global population grows and the climate warms, likely
requiring even higher rates of pesticide use for increased
agricultural activity and crop pests (Ippolito et al. 2015).
2.2.3 Nutrient pollution
Untreated sewage carries a large volume of pollutants
to the ocean (Islam and Tanaka 2004) and wastewater
itself contains a number of pollutants: nutrients,
pathogens, plastics, chemicals, pharmaceuticals
and other suspended solids. On a volume basis, raw
sewage discharge is of most concern where sanitation
infrastructure is still developing. For example, in
Southeast Asia, more than 600,000 tons of nitrogen
are discharged annually from the major rivers. These
numbers may become further exacerbated as coastal
population densities are projected to increase from
77 people per square kilometre (people/km2) to 115
people/km2 in 2025 (Nellemann et al. 2008). The global
anthropogenic nitrogen (N) load to fresh water systems
from both diuse and point sources in the period
2002−2010 was 32.6 MMT/yr (Mekonnen and Hoekstra
2015), though only a portion of this might reach the
The accumulated anthropogenic N loads related to gray
water footprints in the period 2002–2010 was 13 × 1012
cubic metres per year, with China contributing about
45 percent to the global total. Twenty-three percent
came from domestic point sources and 2 percent from
industrial point sources (Nellemann et al. 2008). From
2002 to 2010, the global total phosphorous (P) load to
freshwater systems from the sum of anthropogenic
diuse and point sources was estimated to be 1.47
MMT/yr, though only a portion of this might reach the
ocean. About 62 percent of this total load was from
point sources (domestic, industrial) while diuse
sources (agriculture) contributed the remainder. China
contributed most to the total global anthropogenic P
load, about 30 percent, followed by India (8 percent), the
United States (7 percent), and Spain and Brazil (6 percent
each) (Bouwman et al. 2011).
A global indicator of wastewater treatment to inform the
SDGs has been recently created: Wastewater treatment
was normalised by connections to wastewater systems
around the world. The regions with the greatest average
scores (i.e. the most comprehensive wastewater
treatment) are Europe (66.14 ± 4.97) and North America
(50.32 ± 17.42). The Middle East and North Africa (36.45
± 6.33), East Asia and the Pacific (27.06 ± 6.91), Eastern
Europe and Central Asia (18.34 ± 5.40), and Latin America
and the Caribbean (11.37 ± 2.51) had scores falling in the
14 | High Level Panel for a Sustainable Ocean Economy
middle, with some infrastructure lacking. Sub-Saharan
Africa (3.96 ± 1.50) and South Asia (2.33 ± 1.34) have
the lowest scores with extensive needs for wastewater
treatment improvements (Malik et al. 2015). Even where
treatment facilities exist, they may sometimes discharge
untreated sewage into waterways and the ocean due to
decayed infrastructure, facility malfunctions or heavy
rainfall events that overwhelm systems using combined
sewers and stormwater drains (known as combined
sewer overflows).
Nutrient pollution from agricultural sources comes from
using synthetic nitrogen and phosphorus fertilisers and
from discharging animal waste into the ocean, either via
direct runo, rivers or disaster events (e.g. hurricanes).
Globally, humans increased the application of synthetic
nitrogen fertilisers by nine-fold and phosphorous
fertilisers by three-fold between the 1960s and the 2000s
(Sutton et al. 2013). The global agricultural system fixed
50–70 Teragrams (Tg) of N biologically, while nearly
double that, 120 Tg per year of N, was added as synthetic
fertilisers to support the production of crops and grasses
as well as feedstock for industrial animal agriculture
(Galloway et al. 2008; Herridge et al. 2008). A large share
of the human-applied N is lost, including some 40–66
Tg N/yr exported from rivers to the ocean from 2000 to
2010 (Seitzinger et al. 2005; Seitzinger et al. 2010; Voss et
al. 2011; Voss et al. 2013). Estimates show an increase in
the total N and P exports to coastal waters by almost 20
percent and over 10 percent, respectively, from 1970 to
2000 (Seitzinger et al. 2010). Diuse sources, including
agriculture, contributed about 28 percent of the global
total P load to freshwater systems, which eventually lead
to the ocean.
Global crop production is oen seen as the primary
accelerator of N and P cycles. However, the demand
for animal feed produced from dierent crops and
by-products of the food industry has rapidly increased
in the past century. At present, about 30 percent of
global arable land is used for producing animal feed,
probably also involving a similar fraction of fertiliser
use to produce crops for human consumption (Steinfeld
et al. 2006). In addition, total N and P in animal
manure generated by livestock production exceed the
global N and P fertiliser use (Mekonnen and Hoekstra
2018). Livestock production has increased rapidly in
the past century, with a gradual intensification that
has influenced the composition of livestock diets. In
general, intensification is accompanied by decreasing
dependence on open range feeding in ruminant systems
and increasing use of concentrate feeds, mainly feed
grains grown with fertiliser and fed to animals at feedlots
with concentrated manure to manage.
2.2.4 Antibiotics and other
Antibiotics and other pharmaceuticals are present in
most wastewater both from improper disposal (flushing
down sinks or toilets) and from human waste. Where
wastewater treatment facilities exist, treatment primarily
removes solids and pathogens, but is not typically able
to remove pharmaceuticals without advanced treatment
(Keen et al. 2014). A rapid increase (up 65 percent in
defined daily doses) of antibiotic use between 2000
and 2015 was seen globally, with the largest increases
in lower-middle-income countries where wastewater
treatment may be less available (Klein et al. 2018).
Box 3. The Impacts
of Aquaculture
The four primary discharges to the
ocean from ocean-based aquaculture,
as identified and quantified by the
Global Aquaculture Performance
Index, are antibiotics, antifoulants
(primarily copper), parasiticides and
uneaten feed and faeces, the last of
which impacts the biochemical oxygen
demand of the water.a There are
two additional biological impacts—
escaped fish and pathogens—that are
considered out of scope for this paper.
Plastics discharged by aquaculture
are presented at the beginning of
this section. The relative volume and
impacts of these four discharges vary
by species, geography and type of
aquaculture, with impacts ranging
from relatively benign to quite
damaging for the marine environment
and marine life. The index identified
the worst-performing sector as marine
finfish in tropical and subtropical
water, such as groupers, red drum
and cobia, and the worst geography
as Asia, with Asian countries holding
the lowest 15 spots in the species-
country ranking. These countries
tended to score particularly poorly on
biochemical oxygen demand and use
of antibiotics and parasiticides.b
a. Volpe et al. 2013.
b. Volpe et al. 2013
15 Leveraging Multi-Target Strategies to Address Plastic Pollution in the Context of an Already Stressed Ocean |
2.2.5 Heavy metals, persistent organic
pollutants and oil and gas
Urban runo, especially roadway runo, is the primary
source of heavy metals, POPs and oil and other
chemicals from municipal sources, although some
of these can also be contained in wastewater. One
recent example from China shows road runo contains
significant cadmium, chromium, copper, manganese,
nickel, lead and zinc when classifying with a pollution
load index, and that roadways have two to six times
greater metal concentrations than rooop runo (Shajib
et al. 2019).
Pollution from industry refers to any discharges of
hazardous substances, which may be a result of eluent
discharges from manufacturing operations and cleaning
equipment and any accidental spills. Industrial activities
may generate waste that contains heavy metals,
carcinogenic hydrocarbons, dioxins, pesticides, and
noxious organic and inorganic substances. Hazardous
substances are used to produce electrical equipment, oil
and petrochemicals, organic and inorganic chemicals,
pesticides and heavy metals (mercury, arsenic, lead,
cadmium), and are used by the wood/pulp processing
and electroplating industries. Additionally, by-products
of industrial processes include toxic dioxins (e.g. C4H4O2)
produced in the manufacture of certain herbicides and
chlorine from paper pulp bleaching. Hazardous materials
can be explosive, toxic or carcinogenic, and must be
treated and managed appropriately. Like other pollutant
pathways already discussed, industrial pollutants
can enter the ocean directly through point discharges
or by flowing in rivers (water or sediment transport)
to the ocean, but may also come from atmospheric
deposition as illustrated in a river and estuary source
and transport case study of organochlorine compounds
by Wu et al. (2016).
Industrial water consumption comprises 22 percent of
global water use (UN Water 2018). In 2009, industrial
water use in Europe and North America was 50 percent
of total water use compared with 4–12 percent in
developing countries, but it is expected to increase
by a factor of five in the next 10–20 years in rapidly
industrialising countries (UN Water 2018). As far back
as 2002, 160,000 factories were estimated to discharge
between 41,000 and 57,000 tons of toxic organic
chemicals and 68,000 tons of toxic metals into coastal
waters (UNDP 2002). Globally, 80 percent of wastewater,
including some industrial wastewater, is discharged into
the environment without treatment (UN Water 2018).
In the United States, around 60 percent of coastal rivers
and bays had already been degraded by 2006 (UNEP/
GPA 2006). The Mediterranean coastline has faced major
environmental pressures from industrial development,
with wastewater flows from the mineral, chemical and
energy sectors (GRID-Arendal 2013). Meanwhile, China
has discharged approximately 20–25 billion tons per
year of industrial wastewater since 2000 (Jiang et al.
2014). The real number may be even higher, due to
underreporting and a mismatch in both water quality
standards and wastewater standards. In 2018, only about
71 percent of the industrial wastewater was treated
in Vietnam—cra villages near Hanoi, for example,
were discharging 156,000 cubic metres of water a day
into the Red River Delta near the coast (World Bank
2019). The World Bank (2019) also states that treating
22 million cubic metres of wastewater from industrial
clusters along the Nhue-Day River could considerably
improve coastal water quality. The Ganga River, despite
being a sacred river, is heavily polluted by untreated
industrial activities. Seven hundred sixty-four units of
industry generate 501 million litres of wastewater from
tanneries, textile mills, paper, pulp and other sources
(India Ministry of Water Resources 2017). The Tiram River
in Malaysia had high levels of toxics due to the improper
treatment of industrial eluent in 2015 (Asri 2015). Only
one-third of Philippine river systems are considered
suitable for public water supply due to untreated
domestic and industrial wastewater (Asian Development
Bank 2009). These polluted rivers stream to the ocean
and threaten the coastal resources in the Philippines.
Monitoring of fish and macroinvertebrates in Manila
Bay, Philippines, showed the content of cadmium, lead
and chromium were considerable (Sia Su et al. 2009).
Heavy metal pollution for lead and hexavalent chromium
had accounted for 99.2 percent of disease burden from
toxic exposure among those in India, Indonesia and the
Philippines (Chatham-Stephens et al. 2013). Seawater
along the coast of the Korean Peninsula was analysed
for heavy metal concentrations three times from 2009 to
2013 and copper and zinc concentrations were found to
exceed acceptable standards all three times (Lee et al.
2017). Untreated industrial discharges threaten not only
ecosystem services, but potentially billions of people.
16 | High Level Panel for a Sustainable Ocean Economy
2.2.6 Maritime pollution
Pollution into the ocean does not arise only from land;
the ocean is also impacted by ocean-sourced pollution.
Pollution other than plastic (see section 2.1.4 for a
discussion of plastic pollution), results from fishing,
shipping and transportation, cruises, recreational
boating, ocean exploration and other maritime activities.
Similar to land-based sources, wastewater and grey
water contribute to nutrient and chemical loading in
the ocean, and unique to ocean-going vessels, improper
management of bilge water can also cause pollution.
Sewage and grey water are regulated under MARPOL
Annex IV and bilge water under Annex I. Beyond that,
oil spills are one of the most evident forms of ocean
pollution due to large areas that may be impacted and
the visible consequences for seabirds and other marine
wildlife (Palinkas et al. 1993). Most maritime oil spills
occur due to transportation mishaps or accidents on
oil rigs. Less frequently, a sunken vessel or discharge of
oil-containing bilge or ballast water may be released.
Because of policies by the International Maritime
Organization (IMO) and goals to improve safety and
reduce environmental risk, the overall trend of oil spills
from tankers (not including rigs and platforms) has
decreased over time (Kontovas et al. 2010). However,
in 2010 BP’s Deepwater Horizon oil spill resulted in 4.9
million barrels of oil entering the ocean, the largest oil
spill in the history of the petroleum industry; thousands
of scientific papers have assessed the impacts of this oil
spill since it occurred.
2.3 Compounding Effects of
Multiple Pollutants
More than one source and pollutant can cause a
complex mix of stressors on the ecosystem and marine
life, with sometimes synergistic eects (the impact of
the two together is greater than the sum of their
individual impacts).
Box 4. Jakarta Bay
Struggles with Industrial
Jakarta Bay is on the northern coast of
Jakarta Metropolitan City, Indonesia.
Three large rivers, the Citarum,
Ciliwung and Cisadane, flow into
Jakarta Bay. These rivers are used
by inhabitants as well as industry in
the Jakarta, West Java and Banten
Provinces. There has been significant
anthropogenic impact on the Citarum
River dating back to the increase in use
of the area for industrial activities in
the early 1980s.a Septiono et al. (2016)
discovered heavy metals—namely
cadmium, chromium hexavalent, zinc,
mercury, lead and copper—exceeding
the national concentration standards
in the river. The concentrations of lead
and copper in the sediment of Jakarta
Bay increased five and nine times,
respectively, between 1982 and 2002
(Arifin 2004). In 2006–07, sampling
found that sediment distribution in
the estuary of Jakarta Bay consisted
mostly of black clay, which is indicative
of anthropogenic influences from the
Jakarta River Basin.b Sampling done
from June 2015 to June 2016 showed
that around 97,000 debris items
entered the bay daily through nine
rivers, and about 59 percent of it was
macroplastic,c a further stressor on
Jakarta Bay.
Thousands of people, such as fishers
in North Jakarta and those along
the Thousand Islands, depend on
the ecosystem goods and services
provided by the river. However, the
extreme pollution of toxic chemicals,
eutrophication and sediment load in
the area, as well as overexploitation
of marine resources, are threatening
coastal communities. Production of
the capture fishery sector decreased
in the last five years. Fish production
continuously declined from about
35,000 tons in 1999 to almost 18,000
tons in 2002.d Jakarta Bay is under
stress from both intensive fishing
and degraded water quality due to
pollution from both land and marine
sources. Mercury content in green
mussels and arsenic concentrations
in green mussels and tuna samples
in Jakarta Bay are above the national
standard concentrations (1.0 milligram
per kilogram),e yet the polluted green
mussels can be found in local markets.
Despite being highly used for food and
to support livelihoods, Jakarta Bay is a
sea of wastewater and solid waste.
a. Bukit 1995; Parikesit et al. 2005; Dsikowitzky
et al. 2017.
b. Tejakusuma et al. 2009.
c. Cordova and Nurhati 2019.
d. Arifin 2004.
e. Koesmawati and Arifin 2015.
17 Leveraging Multi-Target Strategies to Address Plastic Pollution in the Context of an Already Stressed Ocean |
Distinct pollutants may also enter the ocean through
similar pathways. The municipal sector, for example, is a
source of both plastic waste and wastewater. In general,
wastewater also carries all the contaminants of urban
stormwater runo in addition to pollutants in sewage.
When municipal infrastructure for handling solid and
liquid wastes is lacking, rapid economic development
exacerbates pollution. In some cases, open sewage
canals are sometimes used to ‘manage’ wastewater in
urban systems, yet solid waste on land washes into these
canals and drains into waterways that can lead to the
ocean. In other cases, aging infrastructure incapable of
handling stormwater leaks both sewage and plastic into
waterways from combined sewer overflow events. Just
as negative synergies exist, so do positive ones: Waste
management of the residual solids from wastewater
treatment are oen managed within the solid waste
management sector, and development of infrastructure
to manage biosolids can help properly manage other
solid waste, including plastic waste.
The agriculture sector has the highest input of nutrients
to the ocean. In one of the largest river basins, the
Mississippi River, fertiliser use delivered 64 percent
and 41 percent of the N and P, respectively, to the Gulf
of Mexico. Pasture use delivered another 5 percent
and 38 percent of the contribution, for a total N and
P from agriculture of 70 to 80 percent of the total (by
comparison, urban use is 9 to 11 percent) (Alexander et
al. 2008). The research also found that source reductions
on land near large rivers (nearly 1:1) or quickly flowing
streams (2:1) had the greatest reduction of overall
nutrient loading to the Gulf (Alexander et al. 2008). This
means that in large river basins, it is possible to get a
nearly kg per kg reduction to the ocean by decreasing
fertiliser use and adjusting management of grazelands.
Figure 2 shows use of N and P on land, as well as all the
major watersheds that drain to the ocean.
18 | High Level Panel for a Sustainable Ocean Economy
Figure 2. Global Nitrogen and Phosphorous Applications (minus endorheic basins)
Global Phosphorus
Application (kg/ha
of P fertiliser applied
per grid cell)
Endorheic Riverbasins
Global Nitrogen
Application (kg/ha
of N fertiliser applied
per grid cell)
Endorheic Riverbasins
Notes: These applications could impact the ocean based upon runo and drainage. Kg/ha stands for kilogram per hectare. N stands for nitrogen, and P for
phosphorous. As used here, an endorheic basin is a body of water that has no outflow to other bodies of water, such as rivers or the ocean.
Sources: Potter et al. 2010; Potter et al. 2011a; Potter et al. 2011b. Map created by A. Brooks.
19 Leveraging Multi-Target Strategies to Address Plastic Pollution in the Context of an Already Stressed Ocean |
Box 5. Spotlight on
Vietnam has a coastline of 3,260
kilometres with over 3,000 islands and
114 river mouths and estuaries. Due to
the rapid rate of population increase,
urbanisation and industrialisation, a
large amount of pollution has been
introduced into the coastal zone in
recent decades. The major sources of
pollution discharges into the ocean
include untreated or incompletely
treated eluents from the municipal
and industrial sectors, as well as waste
from agriculture activities and seaport
and tourism activities.
The total amount of domestic
wastewater in both urban and rural
areas in Vietnam is estimated to be
8.7 million cubic metres per day
(million m3/day).a Major pollutants are
nutrients, organic matter, suspended
solids and nitrogen-containing organic
substances. According to the Vietnam
Ministry of Construction, the total
designed capacity of 39 domestic
wastewater treatment plants over the
country is approximately 907,950 m3/
day, which covers only 11 percent
of domestic wastewater.b In Ha Noi
capital and Ho Chi Minh City, the
two largest cities in the country, the
percentage of all domestic wastewater
processed by centralised wastewater
treatment plants is 20.6 percent and
13 percent of the total wastewater,
respectively.c By the end of 2016, 344
industrial zones had been established
with the amount of industrial
wastewater varying in the regions, and
220 industrial zones were in operation
of which 86 percent had a centralised
wastewater treatment plant. Only 98 of
620 industrial clusters, or 16 percent,
were designed with a wastewater
treatment system—and those
treatment systems have been shown
to have a number of limitations. In
addition, wastewater from handicra
villages also contributes to marine
Waste from agricultural activities
also contributes to marine pollution,
especially from the livestock,
aquaculture and crop sectors. The
estimated livestock solid waste—
including nutrients, suspended
solids, organic matter, pathogens and
pharmaceuticals—was reported to
be 47 million tons in 2016, of which
40–70 percent was treated and the
rest discharged into lakes, streams
and rivers.e For instance, 70–90
percent of the wastewater from one
pig farm, comprised of nutrients
(nitrogen), minerals, heavy metals
and pharmaceuticals, was reported
to be excreted into the environment.
Aquaculture activities also release
a large amount of untreated waste
directly into the ocean with high levels
of nitrogen and phosphorus. In 2014,
more than 10 billion cubic metres of
wastewater containing 51,336 metric
tons of nitrogen and 16,070 metric tons
of phosphorus in a pangasius fish farm
were estimated to be discharged to
local canals to eventually end up in the
Mekong Delta River.f
The use of pesticides and chemical
fertilisers in agricultural production
is another major source of surface
water pollution. Fertilizer use is
increasing in Vietnam. From 1983 to
2013, fertiliser consumption increased
nearly seven-fold to 26 MMT in 2013,
and about 80,000–100,000 tons of
pesticides, herbicides and fungicides
were used from 2012 to 2014.g On
average, 20–30 percent of pesticides
and chemical fertilisers applied will
not be retained by plants and will be
washed by rainwater and irrigation
water into surface water resources
as well as accumulate in the soil
and groundwater in the form of
residues. In summary, the pollutants
released by these activities include,
among others, nutrients, organic
chemicals, sediments and pesticides,
which ultimately end up in the sea
of Vietnam. In addition, wastewater
is also discharged from ocean-going
ships, other maritime facilities, ship
building and repair plants, seaports
and freight yards and stores.
The two major river basins in Vietnam,
the Mekong and the Red River,
annually discharge approximately 500
million and 137 billion cubic metres
of water into the ocean, respectively.h
Sediment is discharged from the
Mekong alone at a rate of 36 MMT/
yr, although this is a decrease from
previous estimates since dams are
now reducing that transport.i However,
both of these water and sediment
flows can transport pollutants from the
anthropogenic activities in the river
catchment and coastal areas to the
ocean.j About 13 MMT of solid waste
is mismanaged in Vietnam each year,
with 1.8 MMT of that plastic, and an
estimated 0.28–0.73 MMT entering the
ocean from Vietnam each year.k
In Vietnam, not many studies on
plastics, including microplastics, have
been conducted, although Vietnam is
one of the top countries in the world
in terms of plastic waste.k The plastic
industry during 2010–2015 was the
third-largest industry in terms of
continued on page 20
20 | High Level Panel for a Sustainable Ocean Economy
Box 5. Spotlight on Vietnam,
growth, with an annual increase
of 16–18 percent (following the
telecommunications and textile
industries). The amount of plastic used
per capita increased from 3.8 kg/year
in 1990 to over 41 kg/year in 2015.l
Although there are no oicial statistics
on the amount and varieties of plastic
in the Vietnamese sea, plastic waste,
originating from wastewater and solid
waste from the mainland, can enter
the ocean through 114 river mouths
and estuaries.
Fishing, aquaculture and on-sea
activities are also major sources of
plastic in the Vietnamese sea. Every
day, about 80 tons of plastic waste and
bags are thrown away in Ho Chi Minh
and Ha Noi combined.m In Ho Chi Minh,
microplastics were found in urban
canals with 172,000 to 519,000 items/
m3,n and in the surface water in Can Gio
Sea at a rate of 0.176 ± 0.0 items/m3.o
Vietnam is addressing the plastic
issue on both the national and
regional scales. The government has
released a national action plan for
marine litter (Government of Vietnam
2020). Regionally, the Lower Mekong
Initiative, a multinational partnership
among Cambodia, Laos, Myanmar,
Thailand, Vietnam and the United
States to create integrated subregional
cooperation among the five Lower
Mekong countries, launched in 2009,
is now also working to address plastic
contamination upstream before it gets
to the ocean.
To more eectively address plastic
waste, more research is needed. In
particular, research that provides
a more complete characterisation
of macro and microplastics at
sea is needed, as well as further
study on eective strategies for
managing plastic waste—particularly
microplastics (including microbeads).
a. MONRE 2016.
b. Nam 2016.
c. MONRE 2017.
d. MONRE 2017.
e. MONRE 2016; World Bank Group 2017.
f. World Bank Group 2017.
g. MONRE 2014; World Bank Group 2017.
h. World Bank 2019.
i. Thi Ha et al. 2018.
j. World Bank 2019.
k. Jambeck et al. 2015.
l. VPAS 2019.
m. Vietnam News 2019.
n. Lahens et al. 2018.
o. Hien et al. 2019.
21 Leveraging Multi-Target Strategies to Address Plastic Pollution in the Context of an Already Stressed Ocean |
There are a multitude of potential impacts pollutants
can have on the ocean, which we have categorised
into four types: ecosystem, marine life, human health
and economic. See Table 2 for a brief outline of these
3. Impacts of Ocean
Pollution on Ecosystems,
Marine Life, Human Health
and Economies
Microplastics Potential to alter the
distribution of sediment
dwelling organisms in
Can provide surface
vectors that facilitate the
transport of potentially
harmful microorganisms
Negative eects on
food consumption,
growth, reproduction
and survival across a
wide range of organ-
isms at the individual
Starvation (due to
Potential of exposure
to toxic substances
(in or absorbed by
Trophic transfer
Unknown impact of
ingestion through
consumption of
marine animals
with microplastics
in their tissues
Unknown exposure
to toxic chemicals
due to ingestion
Unknown exposure
to pathogens
Reduction in global
marine ecosystem services
has been estimated at
US$0.5–2.5 trillion1
Table 2. Potential Ecosystem, Marine Life, Human Health and Economic Impacts from Ocean Pollution
22 | High Level Panel for a Sustainable Ocean Economy
Table 2. Potential Ecosystem, Marine Life, Human Health and Economic Impacts from Ocean Pollution
Macroplastics Smothering and impact
on coral reefs
Transport of invasive
At the individual level:
Starvation (due to
Chemical exposure
Increase in mosqui-
to-borne diseases
Potential for expo-
sure to pathogens
Estimated $40 billion in
negative externalities
Global damage to marine
environments from plastic
pollution estimated at a
minimum $13 billion per
Aggregated estimates
across the plastics life cy-
cle concluded that annual
damages from plastic pro-
duction and the current
stock of plastic waste in
the ocean amount to $2.2
Fishermen lose time and
eiciency from catching
trash in nets
Damage to maritime
industries in the APECa
region was estimated at
$1.26 billion per year5
Loss of revenue from tour-
ism, e.g. reducing marine
debris by 100 percent was
estimated to improve the
savings and welfare of
local residents by $148
million over the three-
month summer period6
Other solid waste Additive nutrients to
the ocean as source of
hypoxia (from organic
Source of heavy metals
Ingestion, entrapment
or entanglement
causing impairment
or death
Transport of invasive
15 million people
worldwide work
informally in waste
management in
poor, unhealthy
Risk of entrapment/
bodily injury
Heavy metal
contamination and
exposure (e-waste)
Pathogen exposure
(medical waste)
Fishermen lose time and
eiciency from catching
trash in nets
Debris in water can dam-
age fishing gear and nets
Loss of revenue from
23 Leveraging Multi-Target Strategies to Address Plastic Pollution in the Context of an Already Stressed Ocean |
Pesticides Reduced photosyn-
thetic eiciency of sea
grass, corals and algae
(herbicides), resulting in
chronic stress
Measurable impacts on
seagrass productivity, es-
pecially when combined
with light attenuation
from high sediment loads
from agricultural runo
Can restrict or fully
inhibit coral settlement
and metamorphosis at
concentrations as low as
one part per billion, and
at higher concentrations
can cause coral branch
Death, cancers,
tumours and lesions
on fish and animals,
reproductive inhibi-
tion or failure, sup-
pression of immune
system, disruption of
endocrine system, cel-
lular and molecular
damage, teratogenic
eects, poor fish
health marked by low
red to white blood cell
ratio, excessive slime
on fish scales and
gills, intergeneration-
al eects, and other
physiological eects
such as egg shell
Toxicity via con-
sumption of marine
species who have
bioaccumulated or
biomagnified pesti-
cides in their tissue.
Most at risk are vul-
nerable populations
(children, elderly) in
communities with
high levels of sea-
food consumption
Loss of productivity and
resiliency of seagrass beds
and coral reefs due to pes-
ticide pollution impacts
global economic security
by reducing provision of
ecosystem services that
are essential for human
society. While exact level
of damage is not known,
if we assume a reduction
in productivity of these
ecosystems by 25%, the
annual economic impact
of those pesticides in
the ocean would be $200
billion per year8
Nutrients (N, P) Eutrophication and
Biodiversity losses
Ecosystem losses
Fish kills, red tides
Decreases in popu-
lation and species
diversity with benthic
and fish communities
Release of ammonia
and hydrogen sulfide,
which can be toxic to
marine life
Respiratory irrita-
tion from harmful
algal blooms
(HABs), e.g red tides
Illness from con-
suming seafood
exposed to HABs
Black Sea fishery value
was reduced by 90%
(from roughly $2 billion).
Other economic impacts
included an estimated loss
of $500 million in tourism
A major and extensive red
tide outbreak occurred
along the coast of Hong
Kong and south China,
covering an area of more
than 100 km2. Over 80%
(3,400 tons) of mariculture
fish were killed, and the
total loss was over $40
Major economic impacts
on fisheries, aquaculture
and tourism
Table 2. Potential Ecosystem, Marine Life, Human Health and Economic Impacts from Ocean Pollution
24 | High Level Panel for a Sustainable Ocean Economy
parasiticides, other
The occurrence of
subtherapeutic doses of
antibiotics on bacteria
over a prolonged period
leads to resistance,
which is a threat to the
The occurrence
of subtherapeutic
doses of antibiotics
on bacteria over a
prolonged period
leads to resistance,
which is a threat to
the environment
mutagenic and re-
productive toxicity
Endocrine system
Heavy metals Toxicity to some micro-
organisms and animals,
cancer in animals, uptake
by plants
Increase in the
permeability of the
cell membrane in
phytoplankton and
other marine algae,
leading to the loss of
intracellular constit-
uents and, therefore,
cellular integrity
These include lym-
phocytic infiltration,
lesions and fatty
In addition, cadmium,
lead and mercury are
potential immuno-
suppressants; of
concern is the buildup
of mercury, which
marine mammals
tend to accumulate in
the liver
Acute toxicity at
high doses, chronic
toxicity, cancer,
impacts to the
nervous system and
behaviour (espe-
cially lead)
Industrial chemicals
and persistent
organic pollutantsc
Food chain interactions,
birth defects, cancer,
accumulation and
transformations in the
Abnormal behaviour,
birth defects in fish,
birds, mammals
Biomagnification in
the food chain
behavioural, neu-
rologic, endocrine,
and immunologic
adverse health
Table 2. Potential Ecosystem, Marine Life, Human Health and Economic Impacts from Ocean Pollution
25 Leveraging Multi-Target Strategies to Address Plastic Pollution in the Context of an Already Stressed Ocean |
Table 2. Potential Ecosystem, Marine Life, Human Health and Economic Impacts from Ocean Pollution
Oil and gas Coat and smother ben-
thic areas
Negative impacts on
reproductive health
Carcinomas and pap-
illomas on the lips of
bottom-feeding fish,
as well as changes in
the cell membrane
Severe eye irritation
with subsequent
blindness in seals
Individual birds be-
come unable to swim
or fly and nervous
system abnormalities
can occur
eects of oil toxicity
on aquatic birds occur
through the loss of
egg viability
Localised health
impacts from
immediate expo-
sure, potential for
longer-term impacts
from exposure,
e.g. cancer, mental
health issues if
fisheries and liveli-
hoods are impacted
BP’s Deepwater Horizon
spill in the Gulf of Mexico
is estimated to have cost
the company $61.6 billion
in penalties and fines;
cleanup and remediation;
and payments to aected
companies, communities
and individuals11
The ‘true’ cost of the
2010 Deepwater Horizon
oil spill including loss of
tourism, cost of cleanup,
and loss of fisheries is
estimated to be $144.89
Notes: Pathogens present in human and animal waste discharged to the ocean can infect marine animals, but this is considered out of scope for this analysis.
a. APEC stands for Asia-Pacific Economic Cooperation.
b. These eects are not necessarily caused solely by exposure to pesticides or other organic contaminants, but may be associated with a combination of
environmental stresses such as eutrophication and pathogens.
1. Beaumont et al. 2019.
2. World Economic Forum et al. 2016.
3. UNEP 2014.
4. Forrest et al. 2019.
5. McIlgorm et al. 2008.
6. Leggett et al. 2014.
7. Medina 2008.
8. Cesar et al. 2003.
9. World Bank 2009.
10. Yang and Hodgkiss 2004.
11. Mufson 2016.
12 Islam and Tanaka 2004.
26 | High Level Panel for a Sustainable Ocean Economy
3.1 Impacts of Plastic
3.1.1 Impacts on ecosystems and
marine life
Microplastics have accumulated across a wide range
of environmental compartments including marine,
terrestrial and freshwater habitats as well as in the air
(SAPEA and Academies 2019; Eerkes-Medrano et al.
2015). These areas also include remote locations far from
population centres such as in the deep sea (Woodall
et al. 2015) and the Arctic (Obbard et al. 2014). There is
clear evidence that microplastics are ingested by a wide
range of species including marine mammals, birds, fish
and small invertebrates at the base of the food chain
(Law and Thompson 2014; Lusher 2015). While it has
been shown that particles can pass through the digestive
system and be excreted, it has also been established that
some particles can be retained in the body for several
weeks (Browne et al. 2008; Ory et al. 2018). Microplastics
can also transfer between prey and predator species
within food webs (Watts et al. 2015; Chagnon et al.
2018). Many of the species that have been shown to
be contaminated with microplastics are commercially
important for human consumption (Lusher et al. 2013).
Laboratory experiments indicate that at high doses
ingesting microplastics can induce physical and
chemical toxicity (SAPEA and Academies 2019). The
physical presence of microplastic particles has been
shown to have negative eects on food consumption,
growth, reproduction and survival across a wide range
of organisms, and there is evidence that zooplankton,
non-mollusc invertebrates and juvenile fish are
particularly sensitive (Cole et al. 2015). For example, a
reduction in feeding eiciency has been demonstrated
for zooplankton, lugworms and fish. In addition, when
ingested, microplastics can transfer potentially harmful
chemicals to biota; this can occur as a consequence
of the transfer of hydrophobic chemicals from the
surrounding water or the release of additive chemicals
incorporated at the time of manufacture (Teuten et
al. 2007; Tanaka et al. 2013). While the transfer of
chemicals by plastics to biota has been demonstrated,
it is the dose that determines the poison. In a recent
bird feeding experiment, Roman et al. (2019) found that
plastic ingestion caused higher frequencies of male
reproductive cysts and minor delays in chick growth
and sexual maturity, but did not aect ultimate survival
or reproductive output. With regard to the transfer of
chemicals by plastics from seawater, recent work has
shown that other pathways including direct uptake from
water and natural foods are likely to be more important
pathways than microplastics (Bakir et al. 2016; Koelmans
et al. 2016). Less is known about the risks associated
with the release of additive chemicals from plastic.
Determining the release of additives is particularly
challenging since chemical formulations are not typically
in the public domain (SAPEA and Academies 2019).
Most experimental work on eects has focused on
those on individuals, but there is some evidence of
wider ecological eects including the potential to
alter the distribution of sediment-dwelling organisms
in assemblages (Green 2016) and to influence the
sinking rates of faecal material to the seabed (Cole et
al. 2013). Microplastics also provide a surface that can
readily become colonised by microorganisms including
pathogens and there are concerns that microplastic
particles may therefore provide vectors facilitating the
transport of potentially harmful microorganisms (Zettler
et al. 2013; Kirstein et al. 2016).
Plastic is rapidly colonised by microorganisms
in a marine environment (Harrison et al. 2014).
Plastic surface habitat has even been defined as the
’plastisphere’ in recognition of the unique communities
it harbours (Zettler et al. 2013). In fact, litter items made
with many materials appear to have unique biofilm
communities (Woodall et al. 2018). These communities
include potentially harmful pathogens such as Vibrio spp.
(Kirstein et al. 2016) and E. coli (Rodrigues et al. 2019)
and are known to colonise the surfaces of submerged
plastic surfaces, similar to how they colonise other hard
submerged surfaces (Shikuma and Hadfield 2010). A
submerged plastic cup laid on a seagrass meadow can
serve as a home for more than 500 individual meiofauna,
which potentially aects meiofauna community
structure (Susetiono 2019). These communities might
also impact biogeochemical cycles (Cornejo-D’Ottone et
al. 2020).
It is important to recognise that most studies of physical
and particle toxicity have been conducted using
concentrations and/or particle sizes that are not typical
of those currently recorded in the environment (Lenz
27 Leveraging Multi-Target Strategies to Address Plastic Pollution in the Context of an Already Stressed Ocean |
rays, sawfish, turtles, seabirds, crocodiles, dugongs,
whales, dolphins and numerous other marine taxa.
Ghost nets can also damage fragile habitats (such as
by smothering or breaking coral reefs (Sheavly and
Register 2007), entangle propellers, cause navigation
hazards to other vessels (Gunn et al. 2010; Hong et al.
2017) and transport invasive species (Macfadyen et al.
2009). Impacts can be substantial—it has been estimated
that in the Gulf of Carpentaria in northern Australia
alone, derelict nets have likely
entangled more than 10,000 sea
turtles (Wilcox et al. 2013).
Ingestion of plastic debris
There are numerous
demonstrated eects of plastic
ingestion by marine fauna. These
may include not only death (van
Franeker 1985; Schuyler et al.
2012; Wilcox et al. 2015) but also
reduction in body mass (Schuyler
et al. 2012), starvation that may
result from the physical blockage
of the gut (van Franeker 1985;
Laist 1987; Acampora et al. 2014;
Hardesty et al. 2015), ulceration
or perforation of the digestive
tract (van Franeker 1985; Laist
1987; Schuyler et al. 2012) and
potential toxicity due to sorption
of chemicals contained within
and sorbed to the plastic (Teuten
et al. 2009). In some studies,
incidence of plastic ingestion
was as high as 60–80 percent
or more of individuals sampled
(crustaceans as reported by
(Murray and Cowie 2011); green
turtles in Brazil as reported by
(Bugoni et al. 2001) and deep sea
species as reported by (Jamieson
et al. 2019).
Chemical contamination from plastic debris
At present, far less is known and understood about
the eects of chemical contamination (which takes
place through ingesting plastic) than impacts from
et al. 2016). There are challenges since environmental
concentrations are not known with confidence,
especially for particles smaller than 300 micrometres,
which are less likely to be collected from water using
conventional net sampling. Plastics can fragment
because of environmental exposure and so the
abundance of very small particles in the nano-size range
could be considerable. These particles are currently too
small to detect in environmental samples, but laboratory
studies show the potential for these particles to transfer
from the gut to the circulatory system with the potential
to rapidly become widely distributed in organisms
(Brandelli 2020). More work is needed to understand
the potential toxicological impacts of this. Despite the
uncertainties about environmental concentrations in
relation to evidence of harm, there is some consensus
based on risk assessment approaches that if microplastic
emissions to the environment remain the same or
increase the ecological risk may become widespread
within a century (SAPEA and Academies 2019).
To date, around 700 species of marine life have
been demonstrated to interact with plastic (Gall and
Thompson 2015), with the main impacts occurring
through entanglement, ingestion and chemical
contamination (Wilcox et al. 2015). Far more is known
about harm to individuals through interaction with
plastic than is known about harm to populations,
species and ecosystems within the marine environment
(Rochman 2015).
Entanglement in plastic debris
Impacts on marine systems from entanglement are
most commonly associated with abandoned, lost, or
derelict fishing gear. Called ‘ghost fishing’, derelict
fishing nets can continue to indiscriminately catch fish
(and other marine organisms) for weeks, months or
decades, which, in addition to impacting ecosystems
and marine life, results in food security issues through
lost resources to feed the world’s population (and the
associated economic consequences of lost revenue).
With an estimated 640,000 tons of gear lost to the ocean
each year per a census taken a decade ago (Macfadyen
et al. 2009), some areas have reported up to three tons
of derelict nets per kilometre of coastline in a given year
(Wilcox et al. 2013). Derelict nets have been reported to
ensnare or entangle invertebrates, crabs, fish, sharks,
Plastics can
because of
exposure and so
the abundance
of very small
paticles in
the nano-size
range could be
More work
is needed to
the potential
impacts of this.
28 | High Level Panel for a Sustainable Ocean Economy
entanglement. In laboratory experiments, it has
been demonstrated that ingested plastic can induce
hepatic stress in fish (Rochman et al. 2013). Plasticisers
(soening and other chemical agents such as dibutyl
phthalate and diethylhexyl phthalate that are oen
added to plastics) have been detected in the preen
gland oil of wild-caught seabirds, with higher levels of
plasticisers found in birds that had eaten more plastic
pieces (Hardesty et al. 2015). Polystyrene, heavily used in
fisheries and aquaculture, is also of particular concern,
as styrenes have been shown to leach into marine
systems (Kwon et al. 2015). Jamieson et al. (2019) found
plastics in animals in some of the deepest parts of the
ocean. Endocrine-disrupting compounds leaching into
tissues from plastics are of increasing concern, not only
for wildlife (Olivares-Rubio et al. 2015), but also for
humans (Meeker et al. 2009; Halden 2010).
3.1.2 Human health impacts
The risk of marine plastic debris to human health
can be measured by the likely exposure of humans to
marine plastic multiplied by the potential for harm by
the plastic. This is not a simple equation, as plastics
comprise many and diverse chemical additives in
addition to their primary polymer component. The
limitless combinations of polymers and additives mean
that each plastic product has a dierent combination
of chemicals, uses and disposal pathways with varying
levels of risk to humans. As a result, plastics should not
be treated as a single product, and need to be addressed
separately (Lithner et al. 2011). To understand the risk,
potential exposure should be identified and quantified,
and the potential for harm, including from factors such
as the concentration of chemical additives, size fraction
(Smith et al. 2018) and ageing (Kedzierski et al. 2018),
should also be determined. Because there are so many
confounding variables and ethical issues, and a lack of
a control group, studying human exposure to various
plastic materials and forms is challenging. This section
outlines exposure pathways, but without reliable
measures for all exposure pathways (pre and post waste)
it is not possible to calculate the relative risk of plastic
waste on human health.
Humans have been exposed to plastics and their
constituent components since they were first mass
produced in the 1940s and 1950s. The growing use
of plastics in primary food packaging has resulted in
increased exposure to them over recent years, and the
increased waste has resulted in more plastic entering
the environment (Jambeck et al. 2015). Consequently, a
host of recent studies have reported microplastics found
in nonmarine foodstus—e.g. honey (Liebezeit and
Liebezeit 2013), beer (Liebezeit and Liebezeit 2014) and
seafood (Rochman et al. 2015)—and the air (Dris et al.
2016). However, realistic measures of humans’ exposure
to plastics have neither been taken nor modelled
(Koelmans et al. 2017).
A recent review (Wright and Kelly 2017) concluded
that toxicity from chemical constituents could occur
via leaching from plastics ingested by eating seafood,
and this also could result in the chronic exposure of
some chemicals due to the bioaccumulation of toxins
in tissues. It is known that additives such as plasticisers
(e.g. phthalates) and bisphenol (BPA) can cause harm
directly or from their breakdown products. For example,
BPA, which has received the most interest to date, can
migrate out of polycarbonate to contaminate food and
drink products (Guart et al. 2013). Once internalised, this
chemical interacts with hormone receptors, resulting
in a complex bodily response (Koch and Calafat 2009).
Plastics are also known to adsorb persistent organic
pollutants and heavy metals once they have become
waste in the natural environment. With a larger surface
area–to–volume ratio, microplastics can act as a
conduit and/or sink for these chemicals, and hence can
transport them into humans through ingestion. Physical
interactions between internal tissues and microplastics
may also be problematic. Smaller particles have been
flagged as the most concerning (reviewed in Galloway
2015), but, again, knowledge gaps mean the potential for
harm is unknown.
Inhaling fibrous material is known to be hazardous to
human health at high concentrations; consequently,
this type of exposure has been monitored by industry
for many years. These studies have shown that fibres
(natural and synthetic), once inhaled, can cause chronic
irritation and inflammation (reviewed by Prata 2018).
29 Leveraging Multi-Target Strategies to Address Plastic Pollution in the Context of an Already Stressed Ocean |
The harm caused at the exposure level generally found in
the environment is unknown.
Littering and human health
The connection between human well-being and
ocean proximity has only recently been investigated,
and studies have revealed that coastal proximity and
blue spaces positively aect well-being (Wheeler et
al. 2012; White et al. 2010). However, beach litter and
microplastics are considered a risk to well-being (Gollan
et al. 2019), and are one of the biggest threats to the
benefits local communities receive from the marine
estate. Litter can undermine the positive eects of a
coastal estate and inhibit beach use (Wyles et al. 2016;
Rangel-Buitrago et al. 2018), potentially reducing
enjoyment outdoors and exercise, both of which are
known to positively aect mental and physical health
(Gladwell et al. 2013). As society begins to better
recognise mental health challenges, this is an area that
requires more research as it could be the most important
influence marine plastic has on human health.
3.1.3 Economic impacts
Plastic pollution in the ocean also has broad economic
consequences. All sectors of the economy use plastic,
and, across sectors, plastic waste is generated in near
proportion to the level of use (Lin and Nakamura 2019).
The full life cycle cost of plastics is not reflected in the
pricing of plastic products (Oosterhuis et al. 2014).
Plastic production is therefore not a fully costed system.
Instead, the economic costs of plastic pollution are
predominantly borne by the environment and by society
(United Nations Environment Assembly of the United
Nations Environment Programme 2017; Forrest et
al. 2019).
The costs of plastic pollution can be broadly divided
into two categories: direct and indirect. The direct
costs of plastic pollution include prevention (e.g.
environmentally sound waste management, awareness-
raising, behaviour change campaigns), remediation (e.g.
beach grading, fishing-for-litter programmes) and direct
damage (e.g. lost productivity from fish mortality or
reduced ecosystem services, repairs to equipment). The
indirect costs of plastic pollution have proven diicult to
quantify, partly due to dierences in the values held by
individuals (such as the importance of a clean beach),
but also due to the challenges in placing an economic
value on a healthy environment. Irrespective of the
categorisation and estimation methodologies, the above
direct and indirect costs are ‘avoidable costs’ (McIlgorm
et al. 2008).
Direct and indirect costs of plastic pollution
The impact of plastic not being a fully costed system
is highlighted by the particularly problematic plastic
packaging sector. It produces a conservatively estimated
$40 billion annually in negative externalities, such as
degradation of natural systems and greenhouse gas
emissions, outstripping the profits of the sector (World
Economic Forum et al. 2016). Including plastic products,
the total environmental cost in 2015 to society from
plastics was estimated to be over $139 billion, which
equated to nearly 20 percent of revenues in the plastic
manufacturing sector (TruCost 2016).
The UN Environment Programme has estimated the
global damage to marine environments from plastic
pollution to be a minimum of $13 billion per year
(UNEP 2014). Moving beyond damage costs to the
environment, the reduction in global marine ecosystem
services has been estimated at $0.5–2.5 trillion, based
on 2011 stocks of marine plastic pollution (Beaumont
et al. 2019). Forrest et al. (2019) aggregated estimates
across the plastics life cycle to conclude that annual
damages from plastic production and the current stock
of plastic waste in the ocean amount to $2.2 trillion.
The European Parliament’s new measures to regulate
single-use plastics cite benefits including avoiding the
emission of 3.4 million tons of carbon dioxide equivalent
and environmental damages equivalent to €22 billion by
2030, as well as an estimated savings to consumers of
€6.5 billion (EU Comission 2019).
Marine litter and plastics in particular both originate
mainly from sea-based and coastal activities (fishing,
aquaculture, tourism, shipping) and can, in turn,
significantly impact these economic sectors (Newman
et al. 2015; Krelling et al. 2017). For example, fishermen
report nets fouled with plastic litter (Wiber et al. 2012;
Brennan and Portman 2017) sometimes even reaching
levels that cause them to move to areas less polluted
with plastic litter (Nash 1992). Litter accumulating
in the net may also aect the eiciency of the nets
30 | High Level Panel for a Sustainable Ocean Economy
(Eryaşar et al. 2014). Fishermen lose time cleaning
litter out of nets but surprisingly then dump the same
litter overboard (Neves et al. 2015). Similar to cultured
species, commercially caught fish may have ingested
microplastics (see, for example, Rochman et al. 2015),
which could aect the health of the fisheries and,
eventually, the economic value of the catches.
Aquaculture may suer from
marine litter through fouled
holding cages and health risks
to the cultured species, which
may ingest small microplastics.
There is special concern
regarding cultured bivalves,
which have been shown to
contain microplastics in their
tissues in several independent
studies (De Witte et al. 2014; Van
Cauwenberghe and Janssen
2014; Davidson and Dudas 2016;
Li et al. 2016; Li et al. 2018; Li et
al. 2018; Naji et al. 2018; Phuong
et al. 2018; Cho et al. 2019;
Teng et al. 2019). While this is of
concern for consumers, there
are other sources of microplastic
ingestion (e.g. from air on food)
that might far exceed those taken
up by bivalves (Catarino et al.
2018). Interestingly, ingesting
small microplastics (between
1 and 10 micrometres) by
oyster larvae had no eect on
the survival or growth of those
larvae (Cole et al. 2015), but a
similar study on mussel larvae
showed detrimental eects of
microplastic ingestion (Rist et al.
There is also concern of trophic
transfer of microplastics (Nelms
et al. 2018), but a recent study
suggested that large predators
rapidly egest microplastics taken up with their small
prey organisms (Chagnon et al. 2018). Commercially
important crustaceans can contain large numbers of
microplastics, but it is suggested that they significantly
reduce their accumulated microplastic load during
moulting (Welden and Cowie 2016). In addition, the risk
of ingesting microplastics is reduced when the gut is
removed (such as those of fish, crustaceans and most
other species) prior to consumption by humans (Lusher
et al. 2017).
Shipping can be severely impacted as vessels can
get entangled with marine litter, causing high risk of
damage to the ships and injury to mariners and travellers
(Newman et al. 2015; Hong et al. 2017). These risks
might be exacerbated in harbour waters where the same
structures that protect the harbour from wave exposure
accumulate large quantities of marine litter (Aguilera et
al. 2016), including fishing lines (Farias et al. 2018), which
ships can become entangled in.
McIlgorm et al. (2008) estimated damage to maritime
industries in the Asia-Pacific Economic Cooperation
(APEC) region to be $1.26 billion per year in 2008 terms.
For comparison, the gross domestic product for this
same region of 21 member countries was $29 billion in
2008 (McIlgorm et al. 2008). McIlgorm et al. (2020) have
updated these numbers, now estimating $10.8 billion in
damage per year to industries in the marine economy
attributable to marine debris. This is eight times greater
than the previous estimate due to improved data, growth
in the marine economy and an increase in the amount of
plastic in the ocean over that time. By 2050, this damage
is projected to be $216 billion (McIlgorm et al. 2020).
Beach litter may cause annoyance among beach visitors
(Schuhmann et al. 2016; Brouwer et al. 2017; Shen et al.
2019) or even induce people to abandon a heavily littered
beach (Krelling et al. 2017) and travel to more distant,
cleaner beaches (Leggett et al. 2014). A study in South
Korea showed that following a litter event (rains flushing
inland litter onto coastal beaches) visitor numbers
decreased dramatically; the authors estimated income
losses of millions of dollars (Jang et al. 2014a). On tourist
beaches, large amounts of litter are removed daily
(Williams et al. 2016), incurring substantial costs for local
municipalities (de Araújo and Costa 2006). Interestingly,
several studies show that people would be willing to pay
to visit beaches if they were cleaned (Brouwer et al. 2017;
Shen et al. 2019). Besides the impact on the aesthetic
value of beaches (Rangel-Buitrago et al. 2018), litter can
also pose a health risk to visitors (Campbell et al. 2016),
especially to young children (Campbell et al. 2019).
Fishermen lose
time cleaning
litter out of nets
but surprisingly
then dump
the same litter
Similar to
cultured species,
caught fish may
have ingested
which could
affect the health
of the fisheries
and, eventually,
the economic
value of the
31 Leveraging Multi-Target Strategies to Address Plastic Pollution in the Context of an Already Stressed Ocean |
In California, modelling indicated that a 25 percent
reduction in marine debris on all 31 of its beaches would
improve the welfare of local residents by $32 million over
three summer months by improving the welfare value
of beach visits by residents and increasing the number
of visits made. Improving marine debris reduction to
100 percent raised the savings to $148 million for the
same period (Leggett et al. 2014). The chemical burden
and disease cost of endocrine-disrupting chemicals
within the European Union has been estimated at
€119 billion (Trasande et al. 2015), of which some daily
contact is likely via plastics (Feldman 1997; Magliano
and Lyons 2013). The environmental costs of marine
plastic pollution are not fully understood. The concern,
however, is of such gravity that the issue is now being
considered within the realm of a planetary boundary
threat (Villarrubia-Gómez et al. 2018).
3.2 Impacts of Other Solid Waste
Inadequate waste collection and uncontrolled dumping
or burning of solid waste still occurs around the world,
but primarily where waste infrastructure is lacking,
oen in low- and middle-income countries (Kaza et al.
2018). This other waste includes all other municipal
waste, medical waste, e-waste and disaster debris, and
mismanagement of it has a range of impacts. Inadequate
sanitation and mismanagement of organic waste and
medical waste can cause exposure to pathogens and
disease, and e-waste mismanagement results in the
release of heavy metals into the environment. For
example, the plastic used to house wires and cases is
oen open burned where informal processing takes
place, releasing dioxin, particulate matter and heavy
metals into the air (Asante et al. 2019).
3.2.1 Impacts on ecosystems and
marine life
Leachate (liquid that accumulates from waste containing
organic compounds as well as heavy metals and POPs)
can drain directly into the ocean (depending on the
proximity of the waste) or into rivers, groundwater
and the soil (Yadav et al. 2019), further contributing to
ocean pollution. Organic waste from garbage can also
contribute to nutrient loading in waterways and the
ocean, and the open burning of solid waste gives o
particulate matter and emissions (Wiedinmyer et al.
2014) that can contribute to atmospheric deposition into
the marine ecosystem. According to the International
Solid Waste Association, greenhouse gas emissions
across the economy—which indirectly impact the ocean
through climate change eects—can be reduced by
15–20 percent with improved global waste management
(UNEP 2015).
3.2.2 Human health impacts
Inadequate waste management, especially open burning
and dumping, around the world produces pollution
(Vasanthi et al. 2008; Wiedinmyer et al. 2014) that
can impact people living near management facilities
and those working directly with solid waste. About
15 million people globally, oen called waste pickers
(who include men, women, children, migrants and the
underemployed), work informally in the waste sector
(Medina 2008). In China alone, it is estimated that 3.3
to 5.6 million people work informally in the recycling of
solid waste (Linzner and Salhofer 2014), and Forrest et
al. (2019) acknowledge the millions of people working
in poor conditions for little money in jobs that would
not qualify as decent work by the International Labour
Organization. While these issues must be addressed,
it is also important to recognise that waste and plastic
management constitute the livelihoods of millions of
people. Any interventions used to address plastic and
other waste must incorporate the views and participation
of informal workers, and especially waste pickers, so
that millions of people aren’t negatively impacted
through the unintended consequences of ‘traditional’
infrastructure, such as eliminating a crucial source of
income (Dias 2016). Women can be disproportionately
harmed by the formalisation of waste management, as
they are typically excluded from formal employment in
the formalized sector. But they can be helped through
inclusive improved recycling operations, capacity
building, provision of equipment, formal training and
awareness building, financial assistance and health
insurance since they have high levels of participation in
the informal sector but oen have less access to these
kinds of benefits (Krishnan and Backer 2019).
3.2.3 Economic impacts
While there are global data on the cost of plastic
pollution (see section 3.1, Impacts of Plastic), there is not
a global number for the cost of mismanaged waste. The
World Bank estimates that proper waste management
32 | High Level Panel for a Sustainable Ocean Economy
infrastructure would cost $50–100 per metric ton (Kaza
et al. 2018), which is in the same range as tipping fees
charged for municipal solid waste disposal in the United
States. In Palau, where the ocean is extremely important
to the economy, the cost of waste-related pollution, or
mismanaged waste (not the cost of waste management
which is estimated at $87 per ton), was estimated at be
$1.9 million per year, which is 1.6 percent of the country’s
gross domestic product and equates to an annual cost of
$510 per household (Hajkowicz SA et al. 2005).
3.3 Impacts of Pesticides
Pesticide mixtures include active and inert ingredients;
both are important, as the active ingredient is the
toxicant for the target organism, and the inert ingredient
oen amplifies the exposure mechanism. For example,
an herbicide with an active ingredient might be
mixed with an inert ingredient that is water soluble to
more eectively penetrate soil, while the same active
ingredient can be mixed with a non-water-soluble oil
to more eectively penetrate the leaf. The same active
ingredient can have dierent toxic eects on the target
organisms, and potential environmental eects, based
on the carrier or inert ingredient. In the United States,
only the active ingredients must be disclosed in pesticide
labelling, making impact assessments very diicult
to conduct.
Pesticides are very eective at improving the eiciency
of agricultural production by reducing crop and animal
losses. However, there are risks associated with pesticide
applications to nontarget organisms. Nontarget
organisms include the people who apply the pesticides,
process the products and consume the products. There
are also risks to nontarget organisms in the fields and
paddocks where these pesticides are applied. Broad
spectrum insecticides kill desirable insects such as
pollinators and the biological predators of undesirable
insects. Some pesticides persist in the environment and
move through the food chain, resulting in toxic impacts
on nontarget organisms including song birds, raptors,
rodents, reptiles and fish (UNEP 2019).
3.3.1 Impacts on ecosystems and
marine life
Pesticides that reach the ocean can impact nontarget
organisms in several ways, depending on the active
ingredient pesticide category, inert ingredient mediator,
transport mechanism and depositional environment.
The toxic impact of pesticides is generally proportional
to the concentration, so very low concentrations
oen have very low impacts. However, pesticides can
be bioconcentrated and biomagnified through the
food chain to result in cumulatively higher impacts
on predators and scavengers (including humans).
Bioconcentration is the process of uptake of a chemical
by an organism from the abiotic environment, resulting
in higher concentrations in that organism than in the
environment (LeBlanc 1995). Bioconcentration of
pesticides occurs when the active ingredient persists
in the environment long enough to be ingested by an
organism such as krill, where it is either metabolised,
excreted or stored in fatty tissues (Cincinelli et al.
2009). The pesticides that are stored in fatty tissues
can persist through many cycles of ingestion, and
thus accumulate in the organism. Biomagnification
is the process whereby the amount of the pesticide
is amplified up the food chain, and the active
ingredient can be concentrated in the fatty tissues
of top predators such as swordfish, sharks and tuna.
These concentrations can be amplified over 1,000-fold
through this process. Most modern pesticides have
been designed to not persist in the environment, and
thus are less prone to bioconcentration. However, early
20th-century pesticides, which are banned in Europe
and the United States but are still manufactured and
used in many countries, can last over 100 years in the
environment and are very prone to bioconcentration
and biomagnification (Dromard et al. 2018). In general,
organochlorine pesticides (OCPs), which were developed
in the early-to-mid 20th century, are the world’s
most persistent legacy pollutants in the ocean. These
include dichlorodiphenyltrichloroethanes (DDTs),
hexachlorocyclohexanes, heptachlor, aldrin, alpha and
beta-endosulfans, dieldrin, endrin, endrin aldehyde,
endrin ketone, methoxychlor, endosulfan sulfate and
heptachlor epoxide (Guo et al. 2007).
Pesticides have been documented to reduce the
photosynthetic eiciency of sea grass, corals and algae
(herbicides), resulting in chronic stress (Brodie et al.
2017). Certain herbicides in common use, including
Diuron, Atrazine, Hexazinone and Tebuthiuron, have
been shown to have measurable impacts on seagrass
productivity, especially when combined with light
attenuation from high sediment loads from agricultural
33 Leveraging Multi-Target Strategies to Address Plastic Pollution in the Context of an Already Stressed Ocean |
runo (Flores et al. 2013). Seagrass beds are critical
habitats for many marine species and support global
fisheries. Insecticides, including organophosphates,
organochlorines, carbamates and pyrethroids, as well
as fungicides, have been shown to restrict to fully inhibit
coral settlement and metamorphosis at concentrations
as low as one part per billion (Markey et al. 2007).
Concentrations just 10 times that amount have caused
coral branch death. These concentrations are at or
below detection levels for conventional laboratory
analyses, rendering these pesticides virtually invisible to
3.3.2 Human health impacts
The primary exposure mechanism to humans from
ocean-borne pesticides is through ingestion of species
that biomagnify those pollutants. The most common
pesticides found in seafood at concentrations above
background levels are OCPs. Communities whose diets
are seafood-based are most at risk given their higher
rates of fish consumption. Consuming fatty piscivores
such as hairtail, mackerel and tuna in South Korea was
shown to increase exposure of vulnerable populations
(children and elderly) to increased OCPs (Moon et al.
2009). In general, these pesticide concentrations are
below chronic toxicity levels for most people (Smith
and Gangolli 2002). Toxicants of concern in fish from
biomagnification include heavy metals (mercury,
cadmium and lead—see section 3.7 on heavy metals),
and legacy organochlorines from industry such as
polychlorinated biphenyls (PCBs) (Storelli 2008).
3.3.3 Economic impacts
The economic impacts of pesticides in the ocean are
largely through decreased productivity rather than
human toxicity. The loss of productivity and resiliency
of seagrass beds and coral reefs is having a significant
impact on global economic security. These critical
ecosystems provide a portfolio of ecosystem services
that are essential for human society, including the
provision of food, water, energy and other resources,
and tourism. The estimated net present value for 2050
of Earth’s coral reefs was almost $800 billion (Cesar et
al. 2003). If pesticides are reducing the productivity
of these ecosystems by only 25 percent, the annual
economic impact of those pesticides in the ocean would
still be $200 billion per year. These critical ecosystems
are also stressed by other pollutants, sediment and
climate change. Some estimates suggest that under a
high greenhouse gas emissions scenario, more than 90
percent of coral reef communities would be lost by 2100
(Speers et al. 2016). Cumulatively, these pose imminent
threats to Earth’s ocean ecosystems.
3.4 Impacts of Nutrient Pollution
3.4.1 Impacts on ecosystems and
marine life
Nutrient pollution, which occurs when anthropogenic
sources of primarily N and P are discharged into marine
systems, leads to eutrophication, algal blooms, dead
zones and fish kills in freshwater and coastal waters.
Scientists have estimated that about 80 percent of large
marine ecosystems in the world already suer from
serious eutrophication, hypoxia and anoxia in coastal
waters (Selman et al. 2008; Diaz et al. 2011; STAP 2011).
In addition, related incidences of toxic algal blooms
such as ‘red tides’ have become more frequent (Rabalais
2002). Eutrophication also leads to habitat changes and
the loss of species of high value (Heisler et al. 2008).
Many species can be impacted directly or indirectly by
nutrients in marine ecosystems as nutrient inputs have
altered the abundances and distributions of marine
species (e.g. through algal blooms). Eutrophication and
oxygen depletion (oen referred to as ‘dead zones’ when
aecting a large area) have direct adverse eects on
coral reefs, seagrass beds, fish and shellfish (Bouwman
et al. 2011). Diaz et al. (2011) identified more than 770
eutrophic and hypoxic coastal systems worldwide, where
70 percent of the areas had documented hypoxia and
almost 30 percent were developing hypoxia. The dead
zone in the Gulf of Mexico resulting from agricultural
runo into the Mississippi River has been studied
extensively, but there is less data on these zones in
developing countries, so these estimates are likely
One example of the direct impact of increased nutrients
in the ocean is the world’s largest macroalgal bloom,
which was recorded from 2011 to 2018 (the most recent
data available). Using satellite images, (Wang et al. 2019)
showed that since 2011, the free-floating mats of brown
macroalgae called Sargassum spp. have increased both
in density and size, generating a long belt of 8,880 km
34 | High Level Panel for a Sustainable Ocean Economy
extending from West Africa to the Caribbean Sea and Gulf
of Mexico. Sargassum is a naturally occurring seaweed
that provides a critical habitat to a diverse array of
species in this ecosystem. However, when the Sargassum
mats overcrowd the coasts, it can impact the movement
of some marine species. When the excess Sargassum
dies and sinks to the ocean bottom in large quantities,
corals and seagrasses can be smothered. On the beach,
rotten Sargassum releases a strong smell, potentially
imposing health challenges for people who have
asthma. Sargassum blooms and their adverse eects
could reduce the number of tourists during a bloom. For
example, in 2018, Barbados had to declare a national
emergency because of a bloom.
The ocean is becoming more stratified, and while there
is still some discussion over coastal marine ecosystems
being N- or P-limited, (Elser et al. 2007) found that,
for coastal systems, N and P limitations play a similar
role, implying that reducing the discharges of both N
and P is important for alleviating pollution in coastal
areas. This is exactly what was shown by (Beman et al.
2005), who found that areas that are nitrogen deficient
were especially vulnerable to nitrogen pollution. They
also found that agricultural runo had a strong and
consistent influence on biological processes, stimulating
algal blooms 80 percent of the time within days of
fertilisation in the Gulf of California. They then projected
that by 2050, 27–59 percent of all nitrogen fertiliser
would be applied in developing regions upstream of
nitrogen-deficient marine ecosystems. These ecosystems
are especially vulnerable to agricultural runo and
nitrogen pollution impacts (Beman et al. 2005).
3.4.2 Human health impacts
Some important drinking water sources (e.g. Lake Erie)
cannot be used during algal blooms, as the toxins either
increase the cost of treatment or make it impossible to
treat. Other human health impacts come from direct
or indirect exposure to toxins resulting from algal
blooms—for example, a red tide can cause ciguatera
poisoning, paralytic shellfish poisoning, neurotoxic
shellfish poisoning (NSP), amnesic shellfish poisoning
and diarrhetic shellfish poisoning, which are the five
most commonly recognised illnesses related to harmful
algal blooms (HABs). Exposure to the toxins from HABs
is mediated through the consumption of contaminated
fish and shellfish, or through exposure to aerosolised
NSP toxins near water bodies where a bloom is occurring
(Grattan et al. 2016).
3.4.3 Economic impacts
Attempts to evaluate the monetary impacts of
eutrophication have been made over the last two
decades. Studies indicate a variety of impacts and costs
that are quantifiable fairly directly, for instance, when
cities of hundreds of thousands of people are deprived of
drinking water for several days. One example is the toxic
algal bloom that occurred in the western Lake Erie basin
in 2011, which led to a disruption of water supplies for
400,000 people (Watson et al. 2016). In another example,
a major and extensive red tide outbreak occurred along
the coast of Hong Kong and south China, covering an
area of more than 100 km2. Over 80 percent (3,400 tons)
of mariculture fish were killed, and the total loss was
over $40 million (Yang and Hodgkiss 2004). On the other
hand, integrating all the environmental, health and
socioeconomic impacts in the calculations of indirect
eects poses more of a challenge.
3.5 Impacts of Antibiotics,
Parasiticides and Other
3.5.1 Impacts on ecosystems and
marine life
Our understanding of the impacts of emerging
contaminants is limited to what has been learned
by studying specific instances where they have been
found and identified; impacts on the overall marine
environment are not well-understood. Pharmaceutical
substances have been examined worldwide in surface
water, groundwater, tap/drinking water, manure, soil and
other environmental matrices. (aus der Beek et al. 2016)
reviewed 1,016 articles and found that pharmaceuticals
or their transformation products have been detected in
the environment of 71 countries covering all continents.
Six hundred thirty-one pharmaceutical substances
were found at levels above the detection limit of the
respective analytical methods employed. Residues of
16 pharmaceutical substances were detected in each
of the five UN regions, and the antibiotic tetracycline
was detected in wastewater treatment plant eluents
in all UN regions. Regional patterns of pharmaceutical
35 Leveraging Multi-Target Strategies to Address Plastic Pollution in the Context of an Already Stressed Ocean |
leakage to the environment emerged as well: Antibiotics
were most prevalent in Asia, analgesics edged out other
pharmaceuticals as most prevalent in Eastern Europe,
lipid-lowering drugs were highest in Europe and Latin
America, oestrogens were found most in Africa, and the
‘other pharmaceutical’ category was predominant in
Western Europe (aus der Beek et al. 2016).
Research presented at the 2019 annual meeting of the
Society of Environmental Toxicology and Chemistry
found that of the sites monitored, 65 percent of them
contained at least one of the 14 most commonly used
antibiotics. These sites were located in rivers in 72
countries across six continents. The concentration of
one antibiotic, metronidazole, found by the researchers
at a site in Bangladesh was 300 times the ‘safe’ level.
(The AMR Industry Alliance recently established ‘safe’
levels of antibiotics in the environment, ranging from
20 to 32,000 nanograms per litre depending on the
antibiotic.) Ciprofloxacin, a general antibiotic used
to treat various bacterial infections, most frequently
exceeded safe levels, surpassing the safety threshold
in 51 places. Geographically, ‘safe’ limits were most
frequently exceeded in Asia and Africa (to the greatest
degree in Bangladesh, Kenya, Ghana, Pakistan and
Nigeria), but sites in Europe, North America and South
America also had levels of concern, showing that
antibiotic contamination is a global problem. Sites with
the highest risk of contamination were typically adjacent
to wastewater treatment systems and waste or sewage
dumps and in areas of political turmoil, including the
Israeli and Palestinian border (University of York 2019).
Benzophenone-2 (BP-2) is an additive to personal-care
products and commercial solutions that protects against
the damaging eects of ultraviolet (UV) light. BP-2 is an
‘emerging contaminant of concern’ that is also oen
released as a pollutant through municipal and boat/
ship wastewater discharges and landfill leachates, as
well as through residential septic fields and unmanaged
cesspits. Although BP-2 may be a contaminant on coral
reefs, its environmental toxicity to reefs is unknown.
This poses a potential management issue, since BP-2
is a known endocrine disruptor as well as a weak
genotoxicant (Downs et al. 2014).
There is concern over the impacts of commonly
used organic UV filters, including oxybenzone
(benzophenone-3), 4-methylbenzylidene
camphor, octocrylene and octinoxate (ethylhexyl
methoxycinnamate), on the marine environment.
Oxybenzone, octocrylene, octinoxate and ethylhexyl
salicylate have been identified in water sources around
the world, and are not easily removed by wastewater
treatment plant techniques (Schneider and Lim
2019). Oxybenzone has been
specifically linked to coral
reef bleaching. In addition,
4-methylbenzylidene camphor,
oxybenzone, octocrylene and
octinoxate have been identified
in various species of fish
worldwide, which has possible
consequences for the food
chain (Schneider and Lim 2019).
Danovaro et al. (2008) found
that even low concentrations of
sunscreens caused bleaching
of corals. The organic UV filter
induces the lytic viral cycle in
symbiotic zooxanthellae with
latent infections. Therefore,
sunscreens may be playing an
important role in coral bleaching
by promoting viral infections
in areas with high recreational
use by humans (Danovaro et al.
3.5.2 Human health
Wastewater treatment plants
are a main source of antibiotics
released into the environment.
An overabundance of antibiotics in wastewater may
generate antibiotic resistance genes and antibiotic
resistant bacteria. Some scientists are concerned that
wastewater treatment plants are becoming hot spots for
resistant genes and bacteria, which has implications for
human health should people get infections that are then
resistant to typical antibiotics (Rizzo et al. 2013).
contamination is
a global problem.
Sites with the
highest risk of
were typically
adjacent to
systems and
waste or sewage
dumps and in
areas of political
36 | High Level Panel for a Sustainable Ocean Economy
3.6 Impacts of Industrial
Chemicals Including Persistent
Organic Pollutants
3.6.1 Impacts on ecosystems and
marine life
Polybrominated diphenyl ethers (PBDEs) and POPs are
toxic, are not easily degradable in the environment,
bioaccumulate in the food chain and undergo long-
range transport (European Environment Agency 2019).
Many industrial chemicals and POPs are known to be
poisonous and to damage the environment and the
organisms living in the aected ecosystems. These
pollutants have become distributed throughout the
ocean and have been found in seemingly pristine
environments. These pollutants also bioaccumulate
in marine organisms such as fish and invertebrates
such as corals, which can lead to various physiological
impairments, varying from subcellular changes such
as direct eects on DNA (deoxyribonucleic acid) to
metabolic stress (Logan 2007; van Dam et al. 2011).
3.6.2 Human health impacts
POPs and PBDEs can cause cancer and toxicity in the
liver, kidneys and reproductive system (Qing Li et al.
2006). The main impacts of industrial pollution to human
health are derived from making direct contact with
contaminated water. The direct contact with polluted
water puts people at risk when the toxins are heavy
metals. The chemical content in the water, whether
carcinogenic or not, may nevertheless play a role in
contributing to cancer mortality risk (Hendryx et al.
2012). Bathing in contaminated water increases the risk
of respiratory disease and skin problems.
Human consumption of marine organisms that have
been contaminated with polluted water is one major
impact of industrial pollution on humans. Many of the
fish that are a primary food source for the indigenous
people in the Canadian Arctic are heavily contaminated
by POPs (Dewailly 2006). While some persistent organic
pollutants have started to decrease in humans and food
in monitored Arctic locations because of international
restrictions, levels of oxychlordane, hexachlorobenzene,
polybrominated diphenyl ether and perfluorinated
compounds are not decreasing (Abass et al. 2018).
Greenland has some of the highest concentrations of
POPs in humans in the Arctic—with the exception of
PBDEs, Greenland populations had the highest measured
levels of POPs than any other Arctic country (Gibson et
al. 2016).
3.6.3 Economic impacts
Studies indicate a variety of economic impacts from
industrial pollution. The tangible economic impacts
include those that occur during pollution incidents as
well as from activities undertaken to prevent, mitigate,
manage, clean up or remedy pollution incidents. The
global economic cost related to the pollution of coastal
waters is $16 billion annually, largely due to human
health impacts (UNEP 2006). An additional source of
cost is the loss of earnings caused by damage to natural
resources. The intangible costs are the loss of marine
biodiversity and the provision of other environmental
services caused by industrial pollution.
3.7 Impacts of Heavy Metals
3.7.1 Impacts on ecosystems and
marine life
Exposure to heavy metals can increase the permeability
of the cell membrane in phytoplankton and other marine
algae, leading to the loss of intracellular constituents
and cellular integrity, and inhibiting metabolism (Sunda
1989; González-Dávila 1995; Hindarti and Larasati 2019).
High trace element burdens in marine mammals have
been associated with lymphocytic infiltration, lesions
and fatty degeneration in bottlenose dolphins, and
decreasing nutritional states and lung pathologies
in other marine mammals (Siebert et al. 1999). In
addition, cadmium, lead and mercury are potential
immunosuppressants; of particular concern is the
buildup of mercury, which marine mammals tend to
accumulate in the liver.
3.7.2 Human health impacts
Mercury and Arsenic: Methylmercury is a neurotoxic
compound responsible for microtubule destruction,
mitochondrial damage, lipid peroxidation and
accumulation of neurotoxic molecules such as serotonin,
aspartate and glutamate (Patrick 2002). Consumption
of contaminated aquatic animals is the major route
of human exposure to methylmercury (Trasande et
37 Leveraging Multi-Target Strategies to Address Plastic Pollution in the Context of an Already Stressed Ocean |
al. 2015). Seafood contaminated by heavy metals or
metalloids such as mercury and arsenic can contribute
to human health risk (Harris et al. 2014; Gao et al. 2018).
One unforgettable case was the mass poisoning of
people in Minamata, Japan, in the 1950s, when 2,252
people were impacted by the contamination and 1,043
died (Harada 1995).
Cadmium and Lead: Consuming fish containing to
cadmium and lead can cause major diseases in humans
such as renal failure, liver damage and symptoms of
chronic toxicity in the kidney (Bosch et al. 2016; Gao et
al. 2016).
Chromium: Because of its mutagenic properties,
hexavalent chromium is a carcinogen that humans can
get exposed to through soils, sediment and surface
waters, as well as some fish (Copat et al. 2018; Tseng et
al. 2019).
3.7.3 Economic impacts
Heavy metal pollution results in substantial economic
impacts to the fishing sector. Bioaccumulation of metals
in fish limits the species that can be safely eaten and the
frequency that those fish can be eaten, and as a result
can limit imports and exports. For example, in 2006,
European Commission Regulation 1881/2006 established
the maximum levels for cadmium, lead and mercury in
food products. High quantities of heavy metals in fish
are one of the principal reasons why fish are detained at
EU borders and the main problem that importers from
non-EU countries must address. The economic losses
deriving from EU border detentions amount to hundreds
of millions of euros each year (FAO n.d.).
3.8 Impacts of Oil and Gas
3.8.1 Impacts on ecosystems and
marine life
Oil spills tend to disproportionately impact sea birds,
which can be harmed and killed by exposure to oil.
Individual birds become unable to swim or fly and
nervous system abnormalities can occur. Population-
level eects of oil toxicity on aquatic birds occur
through the loss of egg viability. Because it is inherently
poisonous, oil in the marine environment has the
potential to harm any creature that comes in contact
with it. This includes larger animals such as sea turtles,
which are sensitive to chemical exposure at all stages
of life and lack an avoidance behaviour, and seals,
which can become blind, as well as smaller organisms,
such as zooplankton and larval fish. Oil spills, and their
associated responses, can be particularly damaging
to fragile but vital marine ecosystems such as coral
reefs and mangroves, but are believed to damage life
throughout the water column. Heavier oils settle and
can coat and smother benthic areas. In areas impacted
by oil spills, bottom-feeding fish have developed
carcinomas and papillomas on their lips, as well as
changes in their cell membranes. Spilled oil can persist
in the environment, continuing to injure and kill marine
life. More research is needed to fully understand the less
obvious impacts of oil spills on the marine environment
(NOAA OR&R 2019).
3.8.2 Human health impacts
A 2016 review article on the human health impacts of
oil spills looked at mental health eects; physical and
physiological eects; and genotoxicity, immunotoxicity
and endocrine toxicity. While there exist a number of
obstacles to calculating human health impacts—such
as challenges to determining exposure levels and the
level of eectiveness of personal protective gear as well
as a reliance on self-reported health symptoms and
variations in genetic sensitivities to chemical exposure—
the authors concluded that there is suicient evidence
to establish a relationship between exposure to oil
spills and the development of adverse health eects in
exposed individuals (Laon et al. 2016).
3.8.3 Economic impacts
Oil spills can be very costly to the responsible companies
as well as to the fishing and tourism industries aected
by the spill. For example, BP’s Deepwater Horizon
spill in the Gulf of Mexico is estimated to have cost the
company $61.6 billion in penalties and fines; cleanup
and remediation; and payments to aected companies,
communities and individuals (Mufson 2016). The sinking
of the Prestige oil tanker in November 2002 o the
coast of Galicia, Spain, resulted in estimated losses to
the Galician fishing sector of €76 million by December
2003 (Surís-Regueiro et al. 2007). Kontovas et al. (2010)
38 | High Level Panel for a Sustainable Ocean Economy
calculated a per metric ton cost for oil spills based upon
a regression of 38 years of oil spill and cost data—the
average value being $4,118 per metric ton in 2009.
3.9 Impacts Summary
Inputs lead to impacts
Based upon the literature reviewed for this Blue Paper,
it is evident that all pollutants discussed in this report
are concerning to our ocean, though some may be more
urgent or easier to address than others. In addition,
multiple pollutants can act synergistically, creating
a greater eect on the ocean than the sum of their
individual impacts. Exploring the present and future
impacts, as was done in this section, is one way to start
to prioritise which pollutants to tackle first. At this
moment, the plastic pollution crisis is very salient—the
issue is tangible and understandable, and countries
around the world are working on solutions because
of marine ecosystem and economic impacts. It is also
evident from this work that nutrient pollution is of great
concern to the ocean. Nutrients contribute to harmful
algal blooms and create low-oxygen hypoxic zones and
stratification, ultimately impacting the health of marine
life and humans. Without changes to either of these two
pollutant input systems in a business-as-usual trajectory,
the impacts from them will get only worse as populations
grow and economies continue to develop. Figure 3
provides a global map showing nitrogen use, along with
the drainage basins and the impact of this drainage
by showing hypoxic areas in the ocean. Urgent action
is needed to protect the ocean from further impacts
from pollution.
Figure 3. Global Nitrogen Use and Hypoxic Areas in the Ocean
Global Nitrogen
Application (kg/ha
of N fertiliser applied
per grid cell)
Endorheic Riverbasins
Note: Mismanaged nitrogen use on land and incidences of eutrophication and hypoxia.
Sources: Data compiled from Potter et al. 2011a; World Resources Institute 2013. Map created by A. Brooks.
39 Leveraging Multi-Target Strategies to Address Plastic Pollution in the Context of an Already Stressed Ocean |
The issue of pollutants leaking into the ocean is entirely
a consequence of human decisions and behaviours. It
is determined by individuals, communities, companies
and politicians, to name but a few of the actors within
the social-environmental system (Pahl and Wyles 2017;
SAPEA and Academies 2019). These actors have varying
perceptions, goals and values that motivate existing
practices (and can also be harnessed for change). For
example, a farmer might decide to employ a pesticide to
increase yield and be willing to accept adverse eects on
wildlife. A cosmetics company might decide to replace
natural ingredients with plastic microbeads to save
money and reduce allergens in their products.
Within the social and behavioural sciences’ research
on environmental pollution, the focus has been on
principles of risk perception and determinants of
behaviour (Pahl and Wyles 2017). In other words, how
does a person or community decide that a pollutant
poses a risk, and what factors motivate behaviour
change (including not just individual actions but also
demand for legislation and policy change)?
Researchers have found that how experts assess risk is
dierent from how non-experts assess risk (see (Böhm
and Tanner 2013). Experts apply scientific methods of
risk assessment that focus on specific thresholds or
outcomes such as fatalities or concentrations, whereas
non-experts judge risk levels using a wide range of
factors such as moral evaluation of the issue, perceived
fairness, perceived control and positive and negative
emotions such as dread and pride. These discrepancies
can contribute to conflict between stakeholders.
Mental model approaches are useful in this context
because they can illustrate dierent expectations
about the sources, pathways and impacts of pollution,
which can provide triggers for change. However, it has
also been noted that perception of risk in itself is not
strongly linked to action, and if too strong, could even
undermine action (Peters et al. 2013). However, when
the risk is associated with an emergency event such as
a natural disaster, this may encourage people to take
action, depending on personal agency, community
capacity and resilience (Brown and Westaway 2011). It
is important to understand risk perception dierences
among stakeholder groups because they can influence
how media reporting is interpreted, and should be taken
into consideration when policies and interventions are
Behavioural practices can contribute to pollution but are
rarely quantified. For example, the dosage of fertilisers
and timing of applications might vary according to
practices and knowledge available to farmers, and fine-
tuning practices could greatly reduce environmental
(and health) impacts. Behaviour is determined by a range
of factors beyond mere knowledge. To illustrate, most
people understand healthy lifestyles but few eat very
healthily and regularly exercise. This is similar in the
environmental domain, where knowledge is one factor
that can motivate behaviour change, but other factors
are more powerful, including perceived control, social
approval and moral norms, among others. In addition,
contextual factors, such as the accessibility and design of
the waste disposal system and availability of materials,
are important. For example, if there is no recycling bin
nearby, a person needs to have a strong motivation to
recycle to put in the extra eort to find one (Pahl and
Wyles 2017; SAPEA and Academies 2019).
To change perceptions and behaviours, a multipronged
approach can target actors individually. Laws, bans
and restrictions are powerful tools that can signal a
social norm of undesirable behaviour. While outlawing
a particular substance can be the most powerful tool,
some materials, such as plastics, are so widespread
that a simple ban would fall short or could be applied
only to certain products. Education and public outreach
campaigns are necessary to accompany policy change
and are powerful instruments in their own right. Good
campaigns build on behavioural science insights
and integrate key elements that have been shown to
work, e.g. empowering individuals, making specific
suggestions for behavioural solutions that are eective
and socially acceptable. It is important not to crowd
out intrinsic motivation but rather to build on personal
4. Human Dimensions
40 | High Level Panel for a Sustainable Ocean Economy
norms and values and develop a pro-environmental
identity as this could spill over into other domains
and behaviours. Eective interventions link to the
target group’s understanding of the issue and to their
motivations and concerns, and build on existing social
networks and channels. Oen, there is initial reluctance
to change (e.g. introduction of seat belts, smoking bans),
but early adopters may forge the path. Trusted members
of a community can trigger wider change and could be
empowered as change agents. Change can happen top
down and bottom up; to target plastic pollution, for
example, there are many examples of community-led
actions, voluntary eorts in the retail sector (e.g. bans on
plastic bags) and nonprofit initiatives.
41 Leveraging Multi-Target Strategies to Address Plastic Pollution in the Context of an Already Stressed Ocean |
Over the last several years, marine plastic pollution has
captured the world’s attention and inspired hundreds
of commitments from governments, businesses and
nongovernmental organisations (NGOs); dozens of
innovation challenges; hundreds of start-up companies
seeking to create solutions; and millions of citizens taking
action, whether as citizen scientists, as part of a beach
clean-up or by changing their own consumption choices.
It is extremely challenging, at least with available data,
to weigh the damage done by marine plastic pollution
against the harmful impacts of nonplastic pollution from
municipal, agricultural, industrial and maritime sources,
though the latter group has been more exhaustively
studied. A more helpful question to ask, however, might
be this: How can action to address plastic pollution
be leveraged to maximise the benefits across as many
other ocean pollutants as possible? If plastic pollution is
uniquely able to catalyse action on solutions, how can
we prioritise and design solutions to also stop the flow of
other pollutants into the ocean?
The seven approaches developed from this research and
presented below begin to address these questions. Each
approach includes recommendations for interventions
and actions to address ocean pollution through four
levers: infrastructure, policy, mindset and innovation.
These levers consider actions that may be taken by
companies large and small, by elected oicials and
policymaking sta, by citizens and by innovators. There
is likely a role for some form of voluntary collective
action from the biggest producers and users of
plastics. In fact, hundreds of companies have signed
on to frameworks such as the New Plastics Economy,
facilitated by the Ellen MacArthur Foundation, and/
or have set goals regarding how they will address
the problem of plastic pollution. This paper does not
speculate about the precise paths companies will take,
but rather focuses on the specific actions most likely to
move the needle on plastic and other types of pollution
reaching our ocean. Aer the details of the approaches
are introduced, they are then summarised and compared
based on their breadth of mitigation across pollutants
and sectors.
In this section, the list of key interventions and actions
are mapped to the following:
Sectors: Municipal (M), agricultural (A), industrial (I),
maritime (Mar)
Types: Infrastructure, Policy, Mindset and Innovation
Pollutants: Sourced from Table 1. Given below each
corresponding intervention table
Relevant UN Sustainable Development Goals (SDGs)
5. Opportunities for Action
i. Create or expand wastewater treatment
capacity (M)
ii. Add tertiary treatment for nutrients and
microplastics (M)
iii. Install toilets (wet or dry) where needed
to prevent open defecation (M)
iv. Install septic tanks where access to muni-
cipal wastewater systems is limited (M)
v. Ensure industrial wastewater is appropri-
ately treated, whether through municipal
or other infrastructure (I)
i. Ensure supporting policies for
wastewater improvements and
sustainability of infrastructure
over time are in place (M)
i. See wastewater as
a natural resource,
especially in water-
constrained regions (M)
i. Develop washing
machine filters for
microplastic fibres (M)
ii. Innovate ways to
remove pharmaceuti-
cals and antibiotics from
eectively and aord-
ably (M)
Sectors: Municipal (M), industrial (I)
Pollutants: Macroplastics; microplastics; other solid waste; nutrients; antibiotics, parasiticides and other pharmaceuticals; heavy metals; and industrial chemicals
and POPs
SDGs: 6.2, 6.3
42 | High Level Panel for a Sustainable Ocean Economy
i. Use natural filters such as berms and clay
to minimise runo into the ocean (A, M)
ii. Implement stormwater and storm drain
filtration and river mouth trash collection
i. Set total maximum daily loads
(TMDLs) for trash (M)
ii. Impose regulatory limits,
TMDLs for discharge (I)
iii. Employ stormwater permit-
ting (M)
iv. Regulate animal waste la-
goons that have the potential
to discharge into the ocean
v. Regulate use of pesticides,
herbicides and nutrients for
residential and commercial
use (M)
vi. Require nutrient manage-
ment plans and pesticide
management plans (A)
vii. Require reporting of and/or
limit usage of nutrients and
pesticides (A)
i. Change cultural norms
around having mani-
cured lawns to reduce
the use of pesticides,
herbicides and fertilisers
used for residential and
commercial landscaping
ii. Create a culture of
responsibility regarding
picking up dog feces (M)
iii. Change habit of wash-
ing with excessive soap,
shampoo and products
that contain high levels
of nitrogen and phos-
phorus (M)
i. Conduct research and
development in storm-
water and other treat-
ment systems (M, A, I)
ii. Change crops, seeds
and farming practices
to minimise nutrient
application prone to
leakage (A)
Sectors: Municipal (M), agricultural (A), industrial (I)
Pollutants: Macroplastics; microplastics; other solid waste; pesticides; nutrients; antibiotics, parasiticides and other pharmaceuticals; heavy metals; industrial
chemicals and POPs; oil and gas
SDGs: None
43 Leveraging Multi-Target Strategies to Address Plastic Pollution in the Context of an Already Stressed Ocean |
i. Construct treatment facilities
with ‘green engineering’ prin-
ciples (M)
ii. Develop infrastructure for the
production of new or alterna-
tive materials
i. Ban or limit the use of
chemicals of concern and
hazardous materials (I)
ii. Ban hard-to-manage
materials (M)
iii. Require tracking/ manifest of
chemicals of concern (I)
i. Adopt green chemistry
principles as a practice for
companies (I)
ii. Change cultural norms around
having manicured lawns to
reduce the use of pesticides,
herbicides and fertilisers
used for residential and
commercial landscaping (M)
i. Develop new materials that
maintain the desirable
performance characteristics
of plastics but not the
problematic ones, e.g. true
biodegradables (M, A)
ii. Develop alternative cleaning
products, e.g. phosphate-free
soap and detergents (M)
iii. Use fish waste or seaweed to
make biopolymers for fishing
gear (A)
iv. Support research and
development in green
chemistry and alternative
chemicals (I)
v. Reduce and prevent tire wear
and tire dust by using new
materials or other
vi. Use new materials for fishing
gear, e.g. biodegradable
components (Mar)
vii. Support the development of
products and services that
do not use any chemicals of
concern (I)
Sectors: Municipal (M), agricultural (A), industrial (I), maritime (Mar)
Pollutants: Macroplastics; microplastics; other solid waste; pesticides; heavy metals; industrial chemicals and POPs
SDGs: 3.9, 12.4
44 | High Level Panel for a Sustainable Ocean Economy
i. Enable the development of circular
business models through shared infra-
structure, for example, reverse logistics or
commercial washing services for reusable
foodservice items (M)
i. Impose fees on single-use or
other high leakage items (M)
ii. Encourage industry volun-
tary contributions to reduce
fossil-fuel-based plastics (M,
A, I, Mar)
iii. Support policies that allow
personal container use in
shopping and dining (M)
iv. Enable treatment and use
of food and human waste
in appropriate applications
(M, A)
i. Change cultural
norms around waste
and reuse, in particular
to reduce the use of
single-use plastic
items (M)
i. Design zero-packaging
grocery stores or include
‘packaging free’ or
‘plastic free’ aisles in
regular grocery stores (M)
ii. Develop new purchasing
models that end
reliance on single-use
plastics (e.g. packaging
as a service, reuse
models) (M)
iii. Pricing structure/busi-
ness model for
nutrients and pesticides
to optimise outcomes
and minimise waste (A)
iv. Require fishing gear
tracking (Mar)
Sectors: Municipal (M), agricultural (A), industrial (I), maritime (Mar)
Pollutants: Macroplastics; microplastics; other solid waste; pesticides; nutrients
SDGs: 8.4, 12.2, 12.5
i. Implement systems for compliance with
bale contamination standards in exported/
imported waste (M)
ii. Deploy technology for advanced waste
drop-o facilities (M)
iii. Use materials that are recyclable and
retain value (M)
iv. Improve technology used at recycling
facilities (M)
v. Use equipment and processes to recover
and recycle chemicals and materials (I)
i. Implement extended producer
responsibility laws (M)
ii. Provide incentives for waste
segregation and recycling (M)
iii. Strengthen markets for recy-
cled plastics (e.g. mandate
use, secure demand, create
price premiums) (M)
iv. Implement Fishing for Litter
programmes (Mar)
i. Change cultural norms
around proper sorting
and recycling (M)
ii. Expand home
composting (M)
iii. Promote and
expand commercial
composting infra-
structure (M)
i. Invest in tracking tech-
nology to combat illegal
dumping (M)
ii. Develop and scale
on-demand waste
collection (M)
Sectors: Municipal (M), agricultural (A), industrial (I)
Pollutants: Macroplastics; microplastics; other solid waste; nutrients; industrial chemicals and POPs
SDGs: 8.3, 8.8, 11.6, 12.2, 12.5
45 Leveraging Multi-Target Strategies to Address Plastic Pollution in the Context of an Already Stressed Ocean |
i. Provide for sediment/dredge material
removal and treatment (I, Mar)
ii. Conduct sediment remediation with in
situ mats (Mar)
iii. Improve wastewater and solid waste
management on ships (Mar)
iv. Build ships and rigs to prevent and mini-
mise oil spills (Mar)
v. Improve infrastructure at ports to manage
waste generated from ships, including
making waste management aordable (M,
I, Mar)
vi. Land solid waste where infrastructure is
available (Mar)
i. Enforce international dumping
agreements (M, Mar)
ii. Strengthen oil spill prevention
policies (M)
iii. Restrict locations and types
of coastal and open-ocean
aquaculture (A)
i. Engage people to adhere
to MARPOL to reduce ille-
gal discharge (Mar)
ii. Ensure that shipping/
maritime developments
prioritise marine protec-
tion (M, Mar)
iii. Operate and manage
oil rigs and ships to
minimise oil spills (I)
iv. Encourage participa-
tion in beach clean-
ups, Adopt-a-Beach
programmes and clean
beach certifications
such as Blue Flag and
Project Aware (M)
v. Use citizen science apps
such as the Debris Track-
er to engage citizens on
pollution issues (M)
i. Innovate equipment and
methods for managing
wastewater and solid
waste on ships (Mar)
ii. Develop new oil spill
prevention technology
iii. Conduct research and
development in individ-
ual pollutant cleanup
systems (I, Mar)
iv. Shi to land-based
aquaculture systems (A)
Sectors: Municipal (M), agricultural (A), industrial (I), maritime (Mar)
Pollutants: Macroplastics; microplastics; other solid waste; pesticides; nutrients; antibiotics, parasiticides and other pharmaceuticals; heavy metals; industrial
chemicals and POPs; oil and gas
SDGs: None
46 | High Level Panel for a Sustainable Ocean Economy
i. Expand drinking water infrastructure (M)
ii. Develop municipal composting systems to
support local food production (M, A)
i. Ensure adequate drinking
water standards (M)
i. Use technology to raise
awareness and provide
practical solutions, e.g.
Fill it Forward and apps
to locate water fountains
ii. Encourage local sourc-
ing of food (e.g. people,
restaurants, govern-
ment) (M)
iii. Encourage people to
bring their own pack-
aging to purchase local
food (M)
iv. Use sustainable meth-
ods of food production
(both on land and aqua-
culture) and minimise
pesticide and nutrient
use (A)
i. Use multitrophic
aquaculture produc-
tion—‘waste’ from one
aquatic species becomes
food for another (A)
ii. Farm mussels, sea grass
or other nutrient-ab-
sorbing species for
nutrient equilibrium (A)
Sectors: Municipal (M), agricultural (A)
Pollutants: Macroplastics; microplastics; other solid waste; pesticides; nutrients; antibiotics, parasiticides and other pharmaceuticals; heavy metals; industrial
chemicals and POPs; oil and gas
SDGs: 6.1, 6.B. 2.1, 2.3
7. Build Local Systems for Safe Food and Water
For comparison purposes, the scope of each intervention
approach is presented in Table 3. As the data do not
exist today to quantitatively compare the value of one
approach versus another, this table focuses on showing
the reach of each intervention by sector for each
pollutant and those directly related SDGs.
47 Leveraging Multi-Target Strategies to Address Plastic Pollution in the Context of an Already Stressed Ocean |
Table 3. Summary of Interventions and Pollutants Addressed across Sectors and SDGs
SDGS 6.2, 6.3 NONE 3.9, 12.4 8.3, 8.8,
11.6, 12.2,
8.3, 8.8,
11.6, 12.2,
NONE 6.1, 6.B,
2.1, 2.3
Microplastics M M M, A M, A, I, Mar M, A, I,
M, Mar M, A
Macroplastics M M M, A, Mar M, A, I, Mar M, A, Mar M, Mar M, A
Other solid
M M M M, A, Mar M, Mar M, A
Pesticides AM, A M, A A
Nutrients (N, P) M, A AM, AM, A A M, A
other pharma-
Heavy metals M, I M, A, I M, A, I, Mar A, I, Mar A
chemicals and
M, I M, A M, A, I, Mar II
Oil and gas M, A, I I, Mar IM, I, Mar
Notes: Sectors are municipal (M), agricultural (A), industrial (I), maritime (Mar)
Bold sectors are the primary scope of influence, non-bold are secondary; cells are shaded progressively darker as more sectors are impacted.
Source: Authors.
Figure 4 presents spider graphs of each intervention to
visually compare their eects on each class of pollutants
across the sectors. These graphs do not illustrate a score
for each intervention, but show the extent to which
they impact pollutants across single or multiple sectors
(depicted by how far the shape spreads outward). In
general, the overall impact increases as more pollutants
and sectors are impacted, but the metrics of mass
quantities, discrete counts and values, as well as risk
and impact, are not able to be taken into account in
these illustrations. However, synergies in addressing
other pollutants while addressing plastic pollution are
48 | High Level Panel for a Sustainable Ocean Economy
Figure 4. Spider Graph Illustrations of Approaches 1–7 by Pollutant and Sector
Other solid waste
Nutrients (N, P)
Oil and gas
and POPs
Heavy metals
and other
How to read these graphs
Shape = intervention
scope and coverage
Other solid waste
Nutrients (N, P)
Oil and gas
and POPs
Heavy metals
and other
Improve waste water infrastructure
Other solid waste
Nutrients (N, P)
Oil and gas
and POPs
Heavy metals
and other
Improve storm water infrastructure
Other solid waste
Nutrients (N, P)
Oil and gas
and POPs
Heavy metals
and other
Adopt green chemistry practices and new materials
Other solid waste
Nutrients (N, P)
Oil and gas
and POPs
Heavy metals
and other
Practice radical resource efficiency
Other solid waste
Nutrients (N, P)
Oil and gas
and POPs
Heavy metals
and other
Recover and recycle the materials we use
49 Leveraging Multi-Target Strategies to Address Plastic Pollution in the Context of an Already Stressed Ocean |
Figure 4. Spider Graph Illustrations of Approaches 1–7 by Pollutant and Sector
Other solid waste
Nutrients (N, P)
Oil and gas
and POPs
Heavy metals
and other
Implement coastal zone improvements
Other solid waste
Nutrients (N, P)
Oil and gas
and POPs
Heavy metals
and other
Build local systems for safe food and water
Source: Authors.
Governments, together with businesses, investors,
individuals, communities and NGOs, can have a
major impact on changing the trajectory of pollution
discharges into the ocean—with the opportunity to
address other intersectional social and environmental
challenges in the process. Solutions will come from
innovative policies, support for research and innovation,
investment in wastewater and solid waste infrastructure
and shiing mindsets and behavioural practices. Many
companies that are facing increased costs—or are
taking responsibility for costs that they have historically
imposed on others—will inevitably claim that these
actions will only result in a loss of jobs, profits and
economic prosperity.
It is important that we don’t confuse the minimisation
of harmful pollution with a reduction in quality of life,
livelihood opportunities or economic success. In fact, the
reality can be quite the opposite. Pollution in the ocean
is already negatively impacting human health, economic
prosperity for ocean-based businesses and marine
ecosystems on which humans depend for essential
ecosystem services. Solutions to ocean pollution can
create jobs, reduce costs to many businesses and
governments and improve the health and prosperity of
millions of people.
Pollution is an externality of a linear economy. In creating
an economic system where product costs nearly always
exclude the environmental impacts for those products
(whether during their creation, useful life or end of life),
we have eectively designed our economies to maximise
pollution, in service of maximising profits. We have
invented the idea of ‘throwing things away’—and the
vastness of the ocean has enabled this fiction to persist
for a very long time.
Alternative economic systems, such as the circular
economy or regenerative economy, begin with the
premise that there is no such thing as waste; that in a
closed system like that of Earth, there is nowhere for
damaging pollution to go that won’t end up harming
ecosystems, plant and animal life and, ultimately,
human life. The branding of an economic model is less
important than this fundamental premise: There is
no ‘away,’ so we must design our economic system to
recognise complete life cycle costs. Once the boundaries
of the economic system are fixed, the machinery of the
economy itself will be very eective at finding the most
eicient ways to stop the problem of pollution.
50 | High Level Panel for a Sustainable Ocean Economy
How one place can make a
While no single community or country can solve the
problem of ocean pollution alone, a single country
can be a first mover in adopting innovative policies
and solutions that show the way for others to follow.
One barrier innovators face is helping to bridge the
imagination gap between today’s and tomorrow’s
realities. A community, country or region can bring the
vision of a pollution-free future to life and make it easier
for others to begin to adopt the same solutions.
Regional strategies
Smaller communities and countries can consider
adopting regional strategies to help achieve critical
mass for certain types of innovations, investments
and infrastructure. For example, regions that align
their requirements for companies to innovate around
packaging, end-of-life responsibility and other issues
can make it more compelling and less complex for
multinational companies to comply.
Global collaboration
The ocean is a global resource impacted by all actions
everywhere. Given this, it would be appropriate and
eective to organise a global compact or commitment
to improving the health of the ocean so the ocean can
better support all life. International treaties have had
success in the past at reducing some impacts on the
ocean (e.g. Montreal Protocol, Stockholm Convention).
As communications and technologies make the
world feel like a smaller place and emphasise the
interconnectedness of humanity and our environment,
there may be openings to build global support for such
an agreement. At a minimum, current declarations from
the G7 and G20, as well as United Nations Environment
Assembly of the United Nations Environment Programme
and other UN initiatives, can be built upon.
Further research
While much has been learned about the scope, scale
and impacts of marine plastic pollution in recent years,
there remain significant gaps that could help inform
and prioritise solutions. There are multiple significant
research eorts underway that were not published in
time to be referenced in this paper. It is the authors’
hope that these studies will be completed and released
as soon as possible as they are expected to contribute
significantly to the state of knowledge on this topic.
Ongoing research on ocean plastic is also needed, and
would be greatly facilitated by the creation of open
data protocols to aggregate and share data globally for
scientific scholarship.
Finally, just as we see synergies in the solutions to ocean
plastic and other pollutants in the ocean, more research
is needed to understand their other interactions in the
ocean as well as their implications.
51 Leveraging Multi-Target Strategies to Address Plastic Pollution in the Context of an Already Stressed Ocean |
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