Plastic Pollution in the World's Oceans: More than 5 Trillion Plastic Pieces Weighing over 250,000 Tons Afloat at Sea
TL;DR: The total number of plastic particles and their weight floating in the world's oceans is estimated from 24 expeditions across all five sub-tropical gyres, costal Australia, Bay of Bengal and the Mediterranean Sea conducting surface net tows and visual survey transects of large plastic debris.
Abstract: Plastic pollution is ubiquitous throughout the marine environment, yet estimates of the global abundance and weight of floating plastics have lacked data, particularly from the Southern Hemisphere and remote regions. Here we report an estimate of the total number of plastic particles and their weight floating in the world’s oceans from 24 expeditions (2007–2013) across all five sub-tropical gyres, costal Australia, Bay of Bengal and the Mediterranean Sea conducting surface net tows (N5680) and visual survey transects of large plastic debris (N5891). Using an oceanographic model of floating debris dispersal calibrated by our data, and correcting for wind-driven vertical mixing, we estimate a minimum of 5.25 trillion particles weighing 268,940 tons. When comparing between four size classes, two microplastic ,4.75 mm and meso- and macroplastic .4.75 mm, a tremendous loss of microplastics is observed from the sea surface compared to expected rates of fragmentation, suggesting there are mechanisms at play that remove ,4.75 mm plastic particles from the ocean surface.
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TL;DR: This work combines available data on solid waste with a model that uses population density and economic status to estimate the amount of land-based plastic waste entering the ocean, which is estimated to be 275 million metric tons.
Abstract: Plastic debris in the marine environment is widely documented, but the quantity of plastic entering the ocean from waste generated on land is unknown. By linking worldwide data on solid waste, population density, and economic status, we estimated the mass of land-based plastic waste entering the ocean. We calculate that 275 million metric tons (MT) of plastic waste was generated in 192 coastal countries in 2010, with 4.8 to 12.7 million MT entering the ocean. Population size and the quality of waste management systems largely determine which countries contribute the greatest mass of uncaptured waste available to become plastic marine debris. Without waste management infrastructure improvements, the cumulative quantity of plastic waste available to enter the ocean from land is predicted to increase by an order of magnitude by 2025.
6,689 citations
Cites background from "Plastic Pollution in the World's Oc..."
...(17) reported 35,540 tons of floating microplastics from plankton net data, and 233,400 tons of “larger plastic items” (> 20 cm in size) from shipboard visual survey data....
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01 Jan 2015
5,515 citations
TL;DR: A global model of plastic inputs from rivers into oceans based on waste management, population density and hydrological information is presented to provide baseline data for ocean plastic mass balance exercises, and assist in prioritizing future plastic debris monitoring and mitigation strategies.
Abstract: Plastics in the marine environment have become a major concern because of their persistence at sea, and adverse consequences to marine life and potentially human health. Implementing mitigation strategies requires an understanding and quantification of marine plastic sources, taking spatial and temporal variability into account. Here we present a global model of plastic inputs from rivers into oceans based on waste management, population density and hydrological information. Our model is calibrated against measurements available in the literature. We estimate that between 1.15 and 2.41 million tonnes of plastic waste currently enters the ocean every year from rivers, with over 74% of emissions occurring between May and October. The top 20 polluting rivers, mostly located in Asia, account for 67% of the global total. The findings of this study provide baseline data for ocean plastic mass balance exercises, and assist in prioritizing future plastic debris monitoring and mitigation strategies. Rivers provide a major pathway for ocean plastic waste, but effective mitigation is dependent on a quantification of active sources. Here, the authors present a global model of riverine plastic inputs, and estimate annual plastic waste of almost 2.5 million tonnes, with 86% sourced from Asia.
2,083 citations
TL;DR: This review critically evaluates the current literature on the presence, behaviour and fate of microplastics in freshwater and terrestrial environments and, where appropriate, draws on relevant studies from other fields including nanotechnology, agriculture and waste management.
1,864 citations
Cites background from "Plastic Pollution in the World's Oc..."
...…of particles are all factors determining transport and 356 fate of particles within these aquatic systems and can lead to large variation, even within a relatively 357 small area (Castañeda et al., 2014; Eriksen et al., 2014; Eriksen et al., 2013; Fischer et al., 2016; Free 358 et al., 2014)....
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...Area 345 of water surface, depth, wind, currents and density of particles are all factors determining transport 346 and fate of particles within these aquatic systems (Eriksen et al., 2014; Eriksen et al., 2013; Fischer et 347 al., 2016; Free et al., 2014)....
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TL;DR: There is potential for microplastics to impact human health, and assessing current exposure levels and burdens is key to guide future research into the potential mechanisms of toxicity and hence therein possible health effects.
Abstract: Microplastics are a pollutant of environmental concern Their presence in food destined for human consumption and in air samples has been reported Thus, microplastic exposure via diet or inhalation could occur, the human health effects of which are unknown The current review article draws upon cross-disciplinary scientific literature to discuss and evaluate the potential human health impacts of microplastics and outlines urgent areas for future research Key literature up to September 2016 relating to accumulation, particle toxicity, and chemical and microbial contaminants was critically examined Although microplastics and human health is an emerging field, complementary existing fields indicate potential particle, chemical and microbial hazards If inhaled or ingested, microplastics may accumulate and exert localized particle toxicity by inducing or enhancing an immune response Chemical toxicity could occur due to the localized leaching of component monomers, endogenous additives, and adsorbed enviro
1,515 citations
Cites background from "Plastic Pollution in the World's Oc..."
...25 trillion plastic particles contaminate the global sea surface, 51 (14) while approximately 4 billion fibres km contaminate the deep Indian Ocean floor....
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References
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TL;DR: It is shown that microscopic plastic fragments and fibers are also widespread in the marine environment and may persist for centuries.
Abstract: Millions of metric tons of plastic are produced annually. Countless large items of plastic debris are accumulating in marine habitats worldwide and may persist for centuries ([ 1 ][1]–[ 4 ][2]). Here we show that microscopic plastic fragments and fibers ([Fig. 1A][3]) are also widespread in the
4,067 citations
TL;DR: Global plastics production and the accumulation of plastic waste are documented, showing that trends in mega- and macro-plastic accumulation rates are no longer uniformly increasing and that the average size of plastic particles in the environment seems to be decreasing.
Abstract: One of the most ubiquitous and long-lasting recent changes to the surface of our planet is the accumulation and fragmentation of plastics. Within just a few decades since mass production of plastic...
4,044 citations
"Plastic Pollution in the World's Oc..." refers background in this paper
...These include UV degradation, biodegradation, ingestion by organisms, decreased buoyancy due to fouling organisms, entrainment in settling detritus, and beaching [4]....
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...Through photodegradation and other weathering processes, plastics fragment and disperse in the ocean [4, 5], converging in the subtropical gyres [6–9]....
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TL;DR: This review of 68 studies compares the methodologies used for the identification and quantification of microplastics from the marine environment and suggests standardized sampling procedures which allow the spatiotemporal comparison ofmicroplastic abundance across marine environments.
Abstract: This review of 68 studies compares the methodologies used for the identification and quantification of microplastics from the marine environment. Three main sampling strategies were identified: selective, volume-reduced, and bulk sampling. Most sediment samples came from sandy beaches at the high tide line, and most seawater samples were taken at the sea surface using neuston nets. Four steps were distinguished during sample processing: density separation, filtration, sieving, and visual sorting of microplastics. Visual sorting was one of the most commonly used methods for the identification of microplastics (using type, shape, degradation stage, and color as criteria). Chemical and physical characteristics (e.g., specific density) were also used. The most reliable method to identify the chemical composition of microplastics is by infrared spectroscopy. Most studies reported that plastic fragments were polyethylene and polypropylene polymers. Units commonly used for abundance estimates are “items per m2” ...
3,119 citations
"Plastic Pollution in the World's Oc..." refers background or methods in this paper
...33 mm, which is a commonly used lower limit for pelagic microplastics [31]....
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...There is a clear need for consistent measures in the field [31], and herein we followed a practical approach using commonly employed boundaries and logistic considerations (net and sieve sizes) in order to integrate an extensive dataset that covers the entire global ocean, including areas that have never been sampled before....
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TL;DR: Model calculations and experimental observations consistently show that polyethylene accumulates more organic contaminants than other plastics such as polypropylene and polyvinyl chloride, and PCBs could transfer from contaminated plastics to streaked shearwater chicks.
Abstract: Plastics debris in the marine environment, including resin pellets, fragments and microscopic plastic fragments, contain organic contaminants, including polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons, petroleum hydrocarbons, organochlorine pesticides (2,2′-bis(p-chlorophenyl)-1,1,1-trichloroethane, hexachlorinated hexanes), polybrominated diphenylethers, alkylphenols and bisphenol A, at concentrations from sub ng g–1 to µg g–1. Some of these compounds are added during plastics manufacture, while others adsorb from the surrounding seawater. Concentrations of hydrophobic contaminants adsorbed on plastics showed distinct spatial variations reflecting global pollution patterns. Model calculations and experimental observations consistently show that polyethylene accumulates more organic contaminants than other plastics such as polypropylene and polyvinyl chloride. Both a mathematical model using equilibrium partitioning and experimental data have demonstrated the transfer of contaminants from plastic to organisms. A feeding experiment indicated that PCBs could transfer from contaminated plastics to streaked shearwater chicks. Plasticizers, other plastics additives and constitutional monomers also present potential threats in terrestrial environments because they can leach from waste disposal sites into groundwater and/or surface waters. Leaching and degradation of plasticizers and polymers are complex phenomena dependent on environmental conditions in the landfill and the chemical properties of each additive. Bisphenol A concentrations in leachates from municipal waste disposal sites in tropical Asia ranged from sub µg l–1 to mg l–1 and were correlated with the level of economic development.
2,114 citations
"Plastic Pollution in the World's Oc..." refers background in this paper
...Adsorption of persistent organic pollutants onto plastic and their transfer into the tissues and organs through ingestion [15] is impacting marine megafauna [16] as well as lower trophic-level organisms [17, 18] and their predators [19, 20]....
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TL;DR: Using data from the Malaspina 2010 circumnavigation, regional surveys, and previously published reports, this work shows a worldwide distribution of plastic on the surface of the open ocean, mostly accumulating in the convergence zones of each of the five subtropical gyres with comparable density.
Abstract: There is a rising concern regarding the accumulation of floating plastic debris in the open ocean. However, the magnitude and the fate of this pollution are still open questions. Using data from the Malaspina 2010 circumnavigation, regional surveys, and previously published reports, we show a worldwide distribution of plastic on the surface of the open ocean, mostly accumulating in the convergence zones of each of the five subtropical gyres with comparable density. However, the global load of plastic on the open ocean surface was estimated to be on the order of tens of thousands of tons, far less than expected. Our observations of the size distribution of floating plastic debris point at important size-selective sinks removing millimeter-sized fragments of floating plastic on a large scale. This sink may involve a combination of fast nano-fragmentation of the microplastic into particles of microns or smaller, their transference to the ocean interior by food webs and ballasting processes, and processes yet to be discovered. Resolving the fate of the missing plastic debris is of fundamental importance to determine the nature and significance of the impacts of plastic pollution in the ocean.
2,078 citations
"Plastic Pollution in the World's Oc..." refers background or result in this paper
...The similarities between our results and those of this study [25] gives us further confidence in our estimates and support our Estimate of Plastic Pollution in the World’s Oceans...
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...This study [25] also found a 100-fold discrepancy between expected microplastic weight and abundance and their observations, indicating a tremendous loss of microplastics....
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...A recent study on the global distribution of microplastic [25] suggests that the total floating microplastic load ranges between 7,000 and 35,000 metric tons, and ours is 35,500 metric tons....
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...Despite oceanographic model predictions of where debris might converge [24] estimates of regional and global abundance and weight of floating plastics have been limited to microplastics ,5 mm [19, 25]....
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