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REFERENCES AND NOTES

mass in 58% (61 out of 105) of countries withavailable data (5).
Plastics in the marine environment
are ofincreasing concern because of their persistence
and effects on the oceans, wildlife, and, potentially, humans (6). Plastic debris occurs on coastlines,in Arctic sea ice,at the sea surface,andon the sea floor (7,8). Weathering ofplastic
Jenna R. Jambeck, 1* Roland Geyer,2 Chris Wilcox, 3 Theodore R. Siegler,4debris causes fragmentation into particles that
Miriam Perryman, 1 Anthony Andrady,5 Ramani Narayan,6 Kara Lavender Law 7even small marine invertebrates may ingest (9).
Its small size also renders this debris untraceable
Plastic debris in the marine environment is widely documented, but the quantity of plasticto its source and extremely difficult to remove
entering the ocean from waste generated on land is unknown. By linking worldwide
from open ocean environments, suggesting thatdata on solid waste, population density, and economic status, we estimated the mass
the most effective mitigation strategies must reof land-based plastic waste entering the ocean. We calculate that 275 million metric
duce inputs.
tons (MT) of plastic waste was generated in 192 coastal countries in 2010, with 4.8 toWe estimated the annual input of plastic to the12.7 million MT entering the ocean. Population size and the quality of waste managementocean from waste generated by coastal populasystems largely determine which countries contribute the greatest mass of uncaptured tions worldwide. We defined mismanaged waste
waste available to become plastic marine debris. Without waste management
as material that is either littered or inadequately
infrastructure improvements, the cumulative quantity of plastic waste available to enter disposed. Inadequately disposed waste is not forthe ocean from land is predicted to increase by an order of magnitude by 2025.
mally managed and includes disposal in dumps
or open, uncontrolled landfills, where it is not
fully contained.
Mismanaged waste could eveneports of plastic pollution in the oceantons (MT)], based only on discharges from ocean
tually enter the ocean via inland waterways,
first appeared in the scientific literature
vessels,
military operations,and ship casualties wastewater outflows, and transport by wind orin the early 1970s, yet more than 40 years(1).The discharge of plastic from at-sea vessels
tides. Estimates of the mass of plastic waste carlater,no rigorous estimates exist of thehas since been banned (2), but losses still occur.
ried by particular waterways range from <<1 kg
amount and origin of plastic debris en-It is widely cited that 80% of marine debris peror- day (Hilo, HI) to 4.2 MT (4200 kg) per day
tering the marine environment.
In 1975,
the es- iginates from land;
however,
this figure is not (Danube River) (10, 11). Because of their depentimated annual flux of litter of all materials wellto thesubstantiated and does not inform the dence
total on local watershed characteristics, theseocean was 6.4 million tons [5.8 million metricmass of debris entering the marine environment
results cannot be easily extrapolated to a global
from land-based sources.
scale.
Plastics have become increasingly dominantHere we present a framework to calculate the1
College of Engineering, University of Georgia, 412 Driftmierin the consumer marketplace since their comamount of mismanaged plastic waste generated
2
Engineering Center, Athens, GA 30602,
Bren
USA.
Schoolofannually by populations living within 50 km of aEnvironmental
Science and Management, University of mercialdevelopment in the 1930s and 1940s.
3
Global plastic resin production reached 288 coast worldwide that can potentially enter the
California, Santa Barbara, CA 93106,
OceansUSA. andAtmosphere Flagship, Commonwealth Scientific and million MT in 2012 (3),a 620% increase since ocean as marine debris. For each of 192 coastal
Industrial Research Organization, Castray Esplanade, Hobart,
1975.
The
largestmarketsector for plastic rescountries with at least 100 permanent residents
4
Tasmania 7000, Australia.
DSM Environmental
Services,5
ins is packaging (3); that is, materials designedthat border the Atlantic,Pacific,and IndianWindsor, VT 05089, USA.
Department of Chemical
andfor immediate disposal. In 1960, plastics madeoceans and the Mediterranean and Black seas,
Biomolecular Engineering, North Carolina State University,
Raleigh, NC 27695, 6USA.
Department of Chemical
up less than 1% of municipal solid waste bythe
mass
framework includes: (i) the mass of waste
Engineering and Materials Science, Michigan State University,in the United States (4); by 2000, this proportion
generated per capita annually; (ii) the percent7
East Lansing, MI 48824, USA.
Sea Education Association,
increased by an order of magnitude.
By 2005, age of waste that is plastic; and (iii) the percentWoods Hole, MA 02543, USA.
plastic made up at least 10% of solid wasteageby of plastic waste that is mismanaged and,*Corresponding author. E-mail: jjambeck@uga.edu
MARINE POLLUTION

Plastic waste inputs from land into
the oceanR

768

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sciencemag.orgSCIENCERESEARCH |REPORTS

therefore,has the potential to enter the ocean
waste to marine debris, we estimated the mass
(13) to project the increase in mass to 2025, andas marine debris (12) (data S1).
By applying a of plastic waste entering the ocean from eachpredicted growth in the percentagewasteofrange ofconversion rates from mismanagedcountry in 2010,
used population growth datathat is plastic.Lacking information on future

Fig. 1. Global map with each country shaded according to the estimated mass of mismanaged plastic waste [millions of metric tons (MT)] generated
in 2010 by populations living within 50 km of the coast. We considered 192 countries. Countries not included in the study are shaded white.

Table 1. Waste estimates for 2010 for the top 20 countries ranked by mass of mismanaged plastic waste (in units of millions of metric tons per year).
Econ classif., economic classification; HIC, high income; UMI, upper middle income; LMI, lower middle income; LI, low income (World Bank definitions
on 2010 Gross NationalIncome).Mismanaged waste is the sum of inadequately managed waste plus 2% littering. mismanaged
Total
plastic waste is
calculated for populations within 50 km of the coast in the 192 countries considered. pop., population; gen., generation; ppd, person per day; MMT, m
metric tons.

Rank

Country

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18*
19
20

China
Indonesia
Philippines
Vietnam
Sri Lanka
Thailand
Egypt
Malaysia
Nigeria
Bangladesh
South Africa
India
Algeria
TurkeyPakistanBrazilBurma
MoroccoNorth Korea
United States

Econ. Coastal pop.
classif.
[millions]
UMI
LMI
LMI
LMI
LMI
UMI
LMI
UMI
LMI
LI
UMI
LMI
UMI
UMI
LMI
UMI
LI
LMI
LI
HIC

262.9
187.2
83.4
55.9
14.6
26.0
21.8
22.9
27.5
70.9
12.9
187.5
16.6
34.0
14.6
74.7
19.0
17.3
17.3
112.9

Waste gen.
% plastic
rate
waste
[kg/ppd]
1.10
0.52
0.5
0.79
5.1
1.2
1.37
1.52
0.79
0.43
2.0
0.34
1.2
1.77
0.79
1.03
0.44
1.46
0.6
2.58

11
11
15
13
7
12
13
13
13
8
12
3
12
12
13
16
17
5
9
13

% mismanaged
waste

Mismanaged % of total
Plastic
plastic
mismanaged
marinewaste
plastic
debris[MMT/year]
waste[MMT/year]

76
83
83
88
84
75
69
57
83
89
56
87
60
18
88
11
89
68
90
2

8.82
3.22
1.88
1.83
1.59
1.03
0.97
0.94
0.85
0.79
0.63
0.60
0.52
0.49
0.48
0.47
0.46
0.31
0.30
0.28

27.7
10.1
5.9
5.8
5.0
3.2
3.0
2.9
2.7
2.5
2.0
1.9
1.6
1.5
1.5
1.5
1.4
1.0
1.0
0.9

1.32–3.53
0.48–1.29
0.28–0.75
0.28–0.73
0.24–0.64
0.15–0.41
0.15–0.39
0.14–0.37
0.13–0.34
0.12–0.31
0.09–0.25
0.09–0.24
0.08–0.21
0.07–0.19
0.07–0.19
0.07–0.19
0.07–0.18
0.05–0.12
0.05–0.12
0.04–0.11*If considered collectively, coastal
European Union countries (23 total) would rank eighteenth on the list

SCIENCEsciencemag.org

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769

RESEARCH |REPORTSglobal infrastructure development,
the projecOur framework was designed to compute,stream
from were capped at 11% (the 192-country avtion represents a business-as-usual scenario.
the best-available data, an order-of-magnitudeerage in 2010), a 26% decrease would be achieve
We estimate that 2.5 billion MT of municipal
estimate of the amount of mismanaged plastic
by 2025. This strategy would target higher-incomsolid waste was generated in 2010 by 6.4 billion
waste potentially entering the ocean worldwide.
countries and might require smaller global inpeople living in 192 coastal countries (93% It
ofis also a useful tool to evaluate the factors
vestments.
deWith a combined strategy, in which
the global population). This estimate is broadly
termining the largest sources of mismanaged
total waste management is achieved (0% misconsistent with an estimated 1.3 billion MT plasticofwaste. The amount of mismanaged plastic
managed waste) in the 10 top-ranked countries
waste generated by 3 billion people in urban
waste generated by the coastal population andof a plastic waste generation is capped as decenters globally (5). Approximately 11% (275singlemil- country ranges from 1.1 MT to 8.8 million
scribedMTabove,a 77% reduction could be reallion MT) of the waste generated by the totalper year,with the top 20 countries’
mismanaged ized, reducing the annual input of plastic waste
population of these 192 countries is plastic.plastic
We
waste encompassing 83% of the total
toin
the ocean to 2.4 to 6.4 million MT by 2025
expectplastic waste to roughly track plastic 2010 (Fig. 1 and Table 1). Total annual waste(tablegen-S3).
resin production (270 million MT in 2010) (3),eration is mostly a function of population size,Sources of uncertainty in our estimates rewith differences resulting from the time lag within the top waste-producing countries having
sult from the relatively few measurements ofdisposal of durable goods (lifetime of years sometoof the largest coastal populations.
Howwaste generation,
characterization,collection,
decades), for example. Scaling by the population
ever, the percentage of mismanaged wasteandis alsodisposal, especially outside of urban centers.
living within 50 km of the coast (those likelyimportanttowhen assessing the largest contribuEven where data were available, methodologies
generate most of the waste becoming marine
tors of waste that is available to enter the enwere not always consistent, and some activities
debris),we estimate that 99.5 million MT of vironment. Sixteen of the top 20 producers were
are not accounted for, such as illegal dumping
plastic waste was generated in coastal regions
middle-income countries, where fast economic(even in high-income countries) and ad hoc rein 2010. Of this, 31.9 million MT were classified
growth is probably occurring but waste mancycling or other informal waste collection (espeas mismanaged and an estimated 4.8 to 12.7
agement
milinfrastructure is lacking (the average
cially in low-income countries). In addition, welion MT entered the ocean in 2010, equivalentmismanaged
towaste fraction is 68%). Only two
didof
not address international import and export
1.7 to 4.6% of the total plastic waste generated
the topin 20 countries have mismanaged fractionsof waste, which would affect national estimates
those countries.
<15%;here,even a relatively low mismanaged
but not global totals. Although national estimates
Our estimate ofplastic waste entering the rate results in a large mass of mismanaged areplassomewhat sensitive to the model predicting
ocean is one to three orders of magnitude greatertic waste because oflarge coastal
populations the percentage of mismanaged waste, the global
than the reported mass of floating plastic debris
and,especially in the United States,
high per estimate and ranking of top countries are not.
in high-concentration ocean gyres and also capita
glob- waste generation.
The long-term projections are also sensitive toally (14–17). Although these ocean estimates Assuming
repno waste management infrastructhe model predicting growth of plastic in the
resent only plastics that are buoyant in seawater
ture improvements, the cumulative quantitywasteofstream; historical growth may not be a(mainly polyethylene and polypropylene),inplastic waste available to enter the marine gooden- indicator of future trends (12). The inclu2010 those resins accounted for 53% of plastic
vironment from land is predicted to increasesion of the economic cost of implementation,
production in North America and 66% of plasby an order of magnitude by 2025 (Fig.
2 and as wellas socio-cultural,environmental,
andtic in the U.S. waste stream (4, 18). Because
table
no S1).The predicted geographic distribu-other factors that affect infrastructure develglobal estimates exist for other sources of plastic
tion of mismanaged plastic waste in 2025 does
opment or behavioral change,
would improve
into the ocean (e.g., losses from fishing activities
not change substantially, although the disparity
the evaluation of mitigation strategies (19).
or at-sea vessels, or input from natural disasters),
between developing and industrialized countries
We will not reach a global“peak waste” bewe do not know what fraction of total
plastic grows (table S2). For example, mismanagedfore
plas2100 (20). Our waste will continue to growinput our land-based waste estimate represents.
tic waste in the United States increases by 22%,with increased population and increased per
whereas in the top five countries it more thancapita consumption associated with economic
doubles.The increase in these middle-income
growth, especially in urban areas and developing
countries results from population growth, waste
African countries (see supplementary materials).
generation rates for 2025 that are consistent
Historically, waste management by burying orwith economic growth (5),and a projected in- burning waste was sufficient for inert or biocrease in plastic in the waste stream.
degradable waste,
but the rapid growth of synThe analytical framework can also be usedtheticto plastics in the waste stream requires aevaluate potential mitigation strategies.
For ex- paradigm shift. Long-term solutions will likely
ample, if the fraction of mismanaged wasteinclude
were waste reduction and “downstream” waste
reduced by 50% (i.e., a 50% increase in adequate
management strategies such as expanded redisposal of waste) in the 20 top-ranked countries,
covery systems and extended producer responthe mass of mismanaged plastic waste would
sibility (21,22).Improving waste management
decrease 41% by 2025.
This falls to 34% if the infrastructure in developing countries is parareduction is only applied to the top 10 countries
mount and will require substantial resources andand to 26% if applied to the top 5. To achieve
time.Whileasuch infrastructure is being devel75% reduction in the mass of mismanaged oped,industrialized
plascountries can take immeFig. 2. Estimated mass of mismanaged plastic waste,
waste management would have to diate
be action by reducing waste and curbing thetic waste (millions of metric tons) input toimproved by 85% in the 35 top-ranked countries.
growth of single-use plastics.
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plastic use would also decrease the amount ofOcean Pollutants to the Ocean Affairs
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10.1126/science.1260352

VIRAL REPLICATION

To gain insight into the mechanism of HCV RNA
replication and its inhibition by nucleotide analog inhibitors, we determined atomic-resolution
ternary structures of NS5B in both primed initiation and elongation states.
Because traditional approaches failed to yield
ternary complexes (see the supplementary materials), we prepared multiple stalled enzyme-RNATodd C. Appleby,1* Jason K. Perry, 1 Eisuke Murakami, 1 Ona Barauskas,1 Joy Feng, 1
nucleotide ternary complex structures containing
1
2
2
1
1
Aesop Cho, David Fox III, Diana R. Wetmore, Mary E. McGrath, Adrian S. Ray,several designed features. First, we used NS5B
Michael J. Sofia, 1 S. Swaminathan,1 Thomas E. Edwards2*
from the JFH-1 genotype 2a isolate of HCV, whichis extraordinarily efficient at RNA synthesis (13).
Nucleotide analog inhibitors have shown clinical success in the treatment of hepatitis
Second, we exploited a conformational stabilizaC virus (HCV) infection, despite an incomplete mechanistic understanding of NS5B, the tion strategy that had been developed for strucviral RNA-dependent RNA polymerase. Here we study the details of HCV RNA replication tural analysis of G protein–coupled receptors (14)by determining crystal structures of stalled polymerase ternary complexes with enzymes,We hypothesized that a triple resistance NS5B
RNA templates, RNA primers, incoming nucleotides, and catalytic metal ions during both mutant isolated under selective pressure of aprimed initiation and elongation of RNA synthesis. Our analysis revealed that highly
guanosine analog inhibitor that exhibits 1.5 times
conserved active-site residues in NS5B position the primer for in-line attack on thethe initiation activity of the wild type (15) mightincoming nucleotide. A b loop and a C-terminal membrane–anchoring linker occlude the stabilize a specific conformational state along
active-site cavity in the apo state, retract in the primed initiation assembly to enforce
the initiation pathway. Indeed, this triple mutant
replication of the HCV genome from the 3′terminus, and vacate the active-site cavity
exhibits a substantial structural
rearrangement
during elongation. We investigated the incorporation of nucleotide analog inhibitors,of the polymerase (15),which is consistent withincluding the clinically active metabolite formed by sofosbuvir, to elucidate key molecularthe structural rearrangement observed in binaryinteractions in the active site.
complexes of a b-loop deletion mutant bound toprimer-template RNA (16). The triple mutant was
epatitis C virus (HCV) is a positive-sense,
polymerase (RdRp), supports a staggering rate
ableofto incorporate native and nucleotide analog
single-stranded RNA virus of the family
viralproduction,estimated to be 1.3 ×1210
viinhibitors with the RNA samples used in structure
determination (fig.
S1).The use of nucleotide
Flaviviridae and genus Hepacivirus andrions produced per day in each infected patientis the cause of hepatitis C in humans (1).
(4).Because the NS5B polymerase active site
diphosphateissubstrates rather than nucleotide
triphosphates (fig. S2) generates stalled polymer
Long-term infection with HCV can leadhighlytoconserved, nucleotide analog inhibitors
in a catalytically relevant conformaend-stage liver disease,including hepatocellularoffer advantages over other classes of HCV complexes
drugs,
tion. Ternary complexes could be obtained only
carcinoma and cirrhosis,
making hepatitis C including activity across different viral genotypes
with Mn2+, which lowers the Michaelis constant
the leading cause of liver transplantation inandthe a high barrier to the development of resistUnited States (2). Direct-acting antiviral drugs
ance (5,6). The nucleotide prodrug sofosbuvir(Km) of the initiating nucleotide (17) and increase2+
the activity of NS5B 20-fold relative
to
(18),
Mg
were approved in 2011, but they exhibited limited
was recently approved for combination treatment2+
efficacy and had the potential
for adverse side of chronic HCV (7, 8).
and only with a nucleotide/Mn/double-stranded
effects (3). The catalytic core of the viral replicaOne substantial obstacle for the rapid discovRNA ratio of 1.0/0.6/0.2.
These approaches designed to stabilize the incoming nucleotide altion complex,
the NS5B RNA-dependentRNA
ery of effective nucleotide-based drugs for HCV
was the lack of molecular detail concerninglowed
sub- for soaking experiments targeting several
distinct assemblies.
strate recognition during replication. NS5B con1
Gilead Sciences,
333 Lakeside Drive,
Foster City,CA 94404, tains several noncanonical polymerase elements,
Hepatitis C virus NS5B initiates RNA synthesis
USA.2Beryllium,
7869 NE Day Road West,
Bainbridge Island,bya primer-independent mechanism. Two slow
includingaC-terminal
membraneanchoringtail
WA 98110,
USA.
steps
thatin the catalytic pathway have been identifie*Corresponding author. E-mail: todd.appleby@gilead.comand a thumb domain b-loop insertion (9–11),
including the formation of an initial dinucleotide(T.C.A); tedwards@be4.com (T.E.E)
are implicated in RNA synthesis initiation (12).

Structural basis for RNA replicationby the hepatitis C virus polymerase

H
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Plastic waste inputs from land into the ocean
Jenna R. Jambeck et al.
Science 347, 768 (2015);
DOI: 10.1126/science.1260352

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