Plastic Pathways

Restructuring MSW Management for Reducing Aquatic Plastic

December 2020
research conducted under Prof. Alejandro Zaera-Polo


Plastic pollution in marine environments has raised significant awareness globally as one of the most threatening environmental problems. There are cumulatively 250,000 tons of plastic currently floating on the ocean surface and buried in the sediments (Eriksen et al., 2014). The biggest waste gathering, known as the Great Pacific Garbage Patch, was estimated to cover an area twice the size of Texas. Ocean plastic exhibited risks by its visible mass and pervasiveness of invisible particles: marine species such as sea turtles, whales were reported getting trapped or injured by abandoned nylon fishing nets and suffered from immobility; plankton ate the disintegrated microplastic particles, transferred toxic contaminants across food chains, causing "developmental, reproductive, neurological, and immune disorders in both human and wildlife" (Gall & Thompson, 2015; Wilcox, Van Sebille, & Hardesty, 2015, Boucher et al. 2017). The urgency of this problem grows with the increased production of virgin plastic. Every year, more than 300 million tons of plastic are produced (Jambeck et al. 2015 ), of which around 8 million tons of plastic enter the ocean, contributing to around 3 percent of global plastic waste. Immediate actions are expected to alleviate the damages caused by ocean plastic pollution.

Max Liborion, a leading scholar in plastic discard studies, argued that "without paying close attention to the ways materials are located within wider material, and social systems, solutions to their presence are often stillborn." Causes and pathways for marine plastic pollution are urged to be analyzed before proposing any systematic changes. Recent surveys (Schmidt et al., 2018) revealed that 80 percent of plastic debris was emitted to the ocean through waterways. More specifically, land-based sources such as industrial waste, combined sewers, landfills, and street rubbish are the main contributors of waste leakages to water systems (Jambeck et al., 2015; Eriken et al., 2014). Marine plastic pollution reflected a more significant arrangement of the current municipal solid waste (MSW) management that too many loopholes and mismanagements are occurring at all stages of waste treatment. Firstly, waste are not properly stored and sorted. Capacities of waste facilities can no longer keep up with the disposal rate, causing a shortage of secured storage spaces for MSW (Borrelle et al., 2020).

Meanwhile, urban runoff carries a large amount of plastic stored openly or within dysfunctional landfill sites. Secondly, long-distance transportation of plastic waste increases the chance of leakages in the process. Developed countries such as the USA, UK, and Germany exported millions of tons of plastic waste annually to developing countries such as China, India, and other southeastern Asian countries. Plastic waste travels across continents and oceans to be recycled; however, due to the lack of well-equipped facilities, they are often mismanaged and contributed to marine debris (Lebreton et al., 2017). Thirdly, there is no capturing infrastructure that acts as the last barrier to prevent plastic waste from entering the ocean. Once plastic enters the waterway, it becomes much more difficult to collect since they continuously break down into smaller pieces until it is impossible to trace.

For plastic waste, the longer path it takes, the further it departs from the source, the more challenging it becomes to tackle. Therefore, strategies for avoiding plastic pollution should focus on investigations near the source of disposal, namely, the countries that produce the most plastic waste. This paper will thereby elaborate on the historically biggest producer globally, the US, by assessing its current limitations of plastic processing policies and waste infrastructure. The paper aims to propose an improved urban framework for comprehensive plastic processing, with concentrations on:

- How can policies be restructured to ensure better management?

- How can infrastructure be improved to address ocean plastic?

Part I: Current Systems for Plastic Waste Processing

Brief History of MSW Treatment in the US

In the US, the MSW treatment system for modern society was first introduced in 1960, during which cities were exposed to health hazards caused by openly burned waste, open-air waste dumping sites, and unlined landfill sites. Congress promulgated the Solid Waste Disposal Act in 1965 to regulate trash disposal with rudimentary requirements (EPA report, 2020). In the late 1970s, the first comprehensive Act, Resource Conservation and Recovery Act (RCRA) was enacted, providing more specific definitions of non-hazardous solid waste versus hazardous waste and strict mandatory requirements for waste disposal, processing, storage, and transportation. Recycling and composting were thereby introduced and promoted as measures to reduce waste generation sustainably. RCRA set up the foundation for MSW policies that extends until this day.

Plastic waste treatment, compared to those of other materials, is a reasonably recent matter. First, man-made plastic was invented in the UK in 1856 as an artificial alternative to ivory. In 1907, Bakelite, the first synthetic polymer made from petroleum, was invented and triggered a swarm for modern polymer material innovations in the 1940s and 1950s. Reaching its prosperity in the 1960s, plastic as a cheap, durable, and malleable material, replaced traditional materials such as paper, glass, and metal, and was broadly applied in packaging and building industries. However, the volume of plastic waste also became alarming ---- in 1960, plastic waste constitutes 0.4 percent of overall MSW; this number accelerated to 12.2 percent in 2018 (EPA report, 2020).

The challenge for plastic waste is that it can hardly be treated without causing any environmental harm since it is categorized as a hazardous material. Firstly, plastic products, depending on their polymer structure, can take from 100 up to 1000 years to decompose (Kershaw et al., 2011) in a landfill site. During transportation, lightweight plastic waste often gets blown away and finds its way to enter the waterways. Secondly, combustion with energy recovery is also tricky with plastic. The by-product of plastic emission contains toxic substances such as Bisphenol A, phthalates, and flame retardants, posing health hazards to humans and animals; combustion also generates greenhouse gas, exaggerating global warming (Verma et al., 2016). Although both scientific research and media widely believe that recycling is the more sustainable way for plastic waste treatment, the reality is that only around 8.5 percent of plastic were recycled in the US in 2018, which was significantly lower than the overall MSW recycling rate of 23.6 percent (EPA report, 2020). The majority of plastic were sent to landfill (77 percent) and incinerator plants (15.7 percent). The reasons behind plastic's low recycling rate in America reveals limitations on both policies and waste infrastructures.

Limitations of MSW Policy

While the government has supported green enterprises such as recycling centers and material recovery facilities by providing fund opportunities and tax reductions, the sustainability of these facilities is subject to factors such as market interest, profit margin, ease of operation, and public awareness. Policies that failed to consider these factors and foresee long-term consequences can inhibit the entire industry's well-functioning.

Waste export is a critical factor for global waste mismanagement driven by policy. For the US and other major plastic producers, plastic recycling is heavily dependent on exporting to less-developed countries. Notably, some policies inversely encourage shipping of plastic waste, rather than processing them domestically, because the prospected expense with all recycling stages is too high for many privately owned facilities to generate any profit. For example, the UK passed the Plastic Recovering Note (PRN) in 2007 as an effort to encourage domestic plastic recycling. The PRN functions as a credit system that gives subsidies to recyclers based on the mass of plastic they recycled. However, for the same amount of raw plastic scrap, domestic recyclers can only receive around 40% of PRN credits due to toxic components such as liquid and stickers, while the exporters earn the full credits despite contamination since everything is processed abroad without examination. The PRN system not only undercut profits from domestic recyclers but also transferred the contaminated non-recyclable waste to the countries they exported to, namely, China, Malaysia, and other southeast Asian countries. Although these countries can still make slim profits out of waste processing due to low labor costs, they also have less developed recycling facilities. In site surveys to several recycling centers in Shenzhen and Bangkok, contaminated water from the machinery covered the entire floor area; plastic bales were stored in open environments where workers sorted usable pieces manually. Poorly managed site conditions in these locations hold them accountable for their high plastic emission into the ocean.

Moreover, the financial incentive for plastic recycling is relatively low compared to virgin plastic production. For recyclers, the value of recycling plastic is typically related to the type of polymer and the size of individual items. By category, only #1 PET (polyethylene terephthalate) and #2 HDPE(High-density polyethylene) are considered profitable for recovery; #4 LDPE,#5 PP, #6 PS, and #7 Other can sometimes be recycled depending on their condition and form; whereas #3 PVC cannot be recycled at all. Furthermore, items below 3 inches, such as single-use plastic bags and bottle caps, are considered of negative value because of their sorting difficulties. However, even the high-value plastics are bearing great competition from virgin materials. In 2020, the price for recycled PET rose to an average of $72/ton above the price of virgin PET plastic (aclima, 2020). This may not affect larger collaborators, but smaller manufacturers may shift to the cheaper virgin PET. Moreover, increased operational cost and lower value for recycled PET have triggered 40 percent of recycling businesses foreclosing in California in the last 5 years, including the largest chain recycler, RePlanet. Unfortunately, as an intermediary between consumption and re-production, recycling companies have very little flexibility to act against market fluctuations. Without a stable demand for recycled materials, either promoted by policies or not, they run the risk of going bust and intensifying the lack of capacity for waste management.

Finally, the current MSW management system pushes all environmental liabilities from consumers to recyclers. For consumers, there is no incentive other than sustainability commitments to pick the more expensive alternatives over plastic. Nationally and state wise, waste disposal standards for consumers are at most instructional with no legal liabilities. Oftentimes in the trash disposal area, materials are displaced and mixed with other materials, adding to the difficulty for post-consumer processing.

Limitations for Waste-processing Infrastructure

The efficacy of waste infrastructure heavily affects the cost and risk associated with recycling. In the US, plastic recovery typically refers to a sequence of systems operated by different agents. Post-consumer waste collection is often operated by each county or individual institutions on a regular basis; sorting is operated by Material Recovery Facilities in which plastics are separated and compressed to single-material bales; reprocessing is operated by individual recyclers who convert sorted plastic items into raw materials. While facility buildings in the US are well-engineered and protected from extreme weather, network settings and machinery defections elongate the waste journey, making plastic harder to return to the market.

In most American cities, waste management adopts the centralized model, meaning waste is transported across long distances from collection points to regional MRFs. MRF is the crucial coordinator that accepts unsorted waste and delivers valuable stacks of materials, whose capacity and service radius discern how fast plastic can reenter the market. The problem with a centralized model is that only a couple MRFs located at the outskirts of a city are covering waste sorting for the entire city. In LA, there are 8 MRFs currently in service. The average distance from MRFs to serviced areas is around 15 miles (calculated from satellite map measurements). Long journeys made between collection sites, MRFs, and reprocessing centers are not only expensive and time-consuming but also increases the risks of mismanagement in transportations. Although MRFs' location may relate to an array of reasons such as zoning regulations, cost of land and hazard prevention, the current network's logistic efficiency needs further investigation to reduce the service radius of MRFs.

Moreover, MRFs are currently limited to sorting only selected types of plastic despite automation. As mentioned above, PET and HDPE plastics can be sorted because of their higher market value. Additionally, optical identification and air-jet are typically used to automatically separate plastics based on transparency and density differences during the sorting process. PET is clear, which is obvious while scanned by the camera, while HDPE has heavier massing, which will be blown into a separate conveyer belt driven by its gravity. The rest of the plastic, however, often contains PP and LDPE, and others that are considered more challenging to be separated are organized into a mixed bale, preparing to be shipped to East Asia. Based on the author's interview with Sims Municipal Recycling in Brooklyn, the biggest MRF in the US processing over 200,000 tons of recyclables each year, the existing automated sorting lines are still limited in precision. For lightweight plastic and smaller pieces, workers at the end of the streamline will need to manually separate the materials, which is somewhat labor-intensive than simply shipping them abroad.

Additionally, the existing collection network has a leak hole in the waterborne plastic collection. As the biggest conveyor of ocean plastic, rivers attract plastic waste from an array of urban sources. Regardless of how engineered, the waste managements are, it is almost inevitable that plastic debris can find its way to the rivers. Cities like LA cleans the riverways regularly, using conventional cranes or small boats. On clear days, floater barriers are installed to trap debris that are floating on the surfaces. However, there is a lack of measures designed for catching most plastic debris, which usually happens in extreme weather. In fact, the abundance of plastic debris was recorded, reaching up to18 times during storm surges, primarily carried by urban runoffs (Castro‐Jiménez et al., 2019). Prevention systems targeted at high aquatic plastic concentrations have not yet been installed to prevent plastic from entering the ocean.

Defections in both policy and infrastructure in the US significantly impact the slow rate and high cost for recycled plastic, forming a dead circle that more virgin plastics are demanded. More emissions are inevitably made. To reduce plastic emissions to the ocean, breakthroughs in systematic optimizations are particularly expected at all scales.

Part II Alternative models for managing plastic waste

Innovations in waste management are appearing globally, initiated by both authorities and private enterprises. These initiatives either challenge the widespread centralized models, or tackle gaps in existing infrastructure through the development of novel and precise plastic collection and processing technologies. Although certain models may not be practical or culturally appropriate to directly replicate in America, their principles and methods can be utilized to form an innovative framework for US plastic recycling policy and infrastructure.

Governmental Initiatives

During the post war boom, Japan experienced rapid economic development and population growth, resulting in increased urban consumption and waste production. While limited by the small territory and scarcity of landfill sites, Japan's waste management has been relying on energy recovery and recycling. Since 1995, domestic waste sorting has been distributed through a plethora of steps, firstly integrated with the waste disposal of every household, followed by centralized sorting in MRFs. Disposal is strictly regulated that PET HDPE and PP are required to be separated first and disposed of at specific locations; violations will be subject to fines and penalties. For an item that contains various materials, the household is responsible for disassembly and categorization. As a result, individuals are forced to participate in waste sorting, which reduces MRFs' workload and ensures a higher recycling rate of plastic. However, applications of the same system are very limited outside of Japan, as it requires individuals to be extremely cautious. The concept of 'early sorting' can be valuable for constructing the US waste framework.

In Germany, specificity in material separation broadened potential applications for recycled plastic. They developed an optimized sorting method that organizes plastic by type and size and identifies the objects' color. Since colorants are commonly added to the polymer, they also affect the properties of plastic in heat resistance, food safety restrictions, Etc. (Sepe, 2016). The same type of plastic of different colors may not be compatible with each other; when combined, they form into a greyish polymer complex, exhibiting uneven qualities depending on the composition. This drastically constrains the reuse applications to only clothing nylons, plant pots, or furniture, which can hardly be recycled again.

Meanwhile, in Eisfeld, a reprocessing company called Systec Plastic GmbH applied an LED scanner that identifies plastic colors and separates colored flakes in repeated circuits. Sorted flakes are turned into pellets and sold to companies with specific requirements. The specification in the sorting procedure boosted recycled plastic's commodity value, however, the re-applications are still consumer goods, which means they will likely return to the MRFs in a short period.

Enterprise Initiatives

While centralized waste management exhibited the limitations of high logistic cost and a long recycling sequence, decentralized waste management models started to take off in India. According to Saahas Zero Waste (SZW), microunits for community waste treatment were established near the residential areas and business campuses, operated directly by the SZW. This significantly streamlines the logistical challenges associated with conventional waste collection and sorting, thereby increasing the net rate of recycling wherever microunits are applied. Another company called Sampurnearth developed an end-to-end decentralized waste management network. The platform analyzes schedules, locations, and capacities of individual recyclers and clients, pairing them with optimized routes and services.

Other innovations are appearing in tackling plastic waste collection in aquatic ecosystems. The Ocean Cleanup is a non-profit organization founded by a young entrepreneur, Byan Slat, from the Netherlands. As a business leader in researching ocean plastic distribution, the group strategically designed their plastic capturing prototypes by targeting a higher concentration of plastic waste. They found out that most plastic (by mass) in vertical water columns are concentrated on the first 1 meter of water surface. This guided them to designing the Boom Floater and Screen system and the Interceptor plastic collector, trapping plastic debris from both oceans and rivers. Although neither of the proposed systems can be permanently integrated into urban environments, the method of trapping surface plastic can be constructive for future urban infrastructures. Recently, the organization is attracting media attention and public funds. However, they have yet to consolidate the product line produced by recycled ocean plastic. Again, converting aquatic plastic to consumer goods is to repeat the circuits of current plastic consumption.

Part III Innovations for Plastic management in Urban Environment

Before entering the ocean, all marine debris once existed somewhere on land. The ocean plastic problem analysis is ultimately a re-examination of the global waste management framework and a reflection on how innovations transform social norms with bipolar consequences. Primary producers such as the USA are urged to take more responsibility and rapidly adjust their MSW management. After identifying the MSW system's flaws and limitations in comparison to successful case studies, potential adjustments are funneled into two objectives: aquatic plastic collection and source reduction. Achieving these changes requires immediate restructuring of waste policies and physical settlements. After all, waste management reform should not stagnate or inhibit urban development, but simply aim to redefine how cities repurpose their ecologically hazardous biproducts in a sustainable fashion.

A Diversified Waste Management Framework

Current MSW management operates linearly, collecting, sorting, reprocessing, and manufacturing work in sequence without cross communications. Loopholes in any of the procedures will likely impact the efficacy of the following steps. Conversely, in Japan and India's models, sorting can be introduced at multiple stages of waste management, either combined with disposal or with collection. Systems can work in redundancy, that not only institutions and counties are in charge of waste collection, but also end-to-end trades are initiated between private owners and recyclers. The shift of the operational model will give opportunities to a much more diverse and comprehensive 'waste landscape' in urban environments.

Existing infrastructures will be more closely connected, meanwhile new infrastructures may take off across the city. On a local scale, since most US cities have yet developed specified waste collection stations, clear instructions and pairing disposal container design are expected to be adopted as defaults of each neighborhood. On an urban scale, MRFs' shortened service radius will optimize logistic efficiency, while decentralized sorting and reprocessing units start to pop up, operated by private enterprises. Innovations such as river plastic capturing systems will be broadly adopted, tackling the current waste leakages and providing end-of-line protections for urban waters.

Policies are essential for guiding this transformation. Specifically, stricter regulations should be enacted with the aim to facilitate the recycling process or reduce the productions of virgin plastic. Regulations should include but are not limited to moderation of colorant use and undetachable mix of plastic (factors that increase sorting difficulty); more substantial economic incentives for domestic recyclers such as business pairings and financial aids. Although material trades and consumer behaviors are primarily affected by the market, policies can play an integral role in governing the sustainability market.

Limitations and Conclusions

An optimized waste management framework may escalate the low recycling rate of plastic. However, the effect may still be slim, considering the overall waste volume. In fact, all evidence now suggests that plastic recycling industries can hardly overturn any profits from recycled materials ---- it will always be an uphill battle. Moreover, waste importers already started to reject waste imports due to the growth of wealth and environmental concerns. Before 2017, mainland China and Hongkong cumulatively imported around 72.4 percent of plastic waste worldwide. In 2017, the Chinese government enacted a strict ban on all imported waste, which shifted the plastic import amount to other Asian countries. In 2019, Malaysia, the biggest importer after China, announced the prohibition of plastic scraps, followed by Thailand, which plans to ban waste imports by 2021. When exporting will no longer be an option for mitigating excessive domestic waste, every country is forced to develop alternatives to cope with waste management.

A noticeable trend is the development of plastic alternatives, such as bioplastics, attracting vast amounts of research and development funds. It is likely that when alternate materials become more affordable in the near future, and America's oil price offers a less competitive margin, the market will eventually turn away from plastic. Recycling still holds significance in that it buys time for this transition and that plastic items will still require some kinds of treatments while fading away. However, instead of turning recycled plastic into consumer goods, storing them in products that can last longer maybe another path moving forward. Building materials such as plastic lumber have been gathering attention since 2000. Combined with wood flakes or fiberglass, it exhibited better structural performance than timbers and is cheaper to produce. Innovations focusing on long-term plastic products deserve further investigation, to store plastic in the thickness of the city, rather than in the vastness of the city.

However, over the last decade, there has been a resurgence of interest in Ota Ward's manufacturing sector. The district is now a key location for experimental high-tech prototyping and development. This is because of "Nakama Mawashi" (literally meaning passing something around to friends). The proximity of different specialist machining centers, with owners often being neighbors and close friends, affords the area a unique collaborative community where groups of machinists assist one another in completing projects. This collaboration ethos allows for abstract concept designs to be rapidly developed into concrete prototypes, which has made the district a beacon for technological innovation. This has led to increased corporate and governmental involvement with the district since 2010, with government-funded urban workshops like the Ota Techno Core being developed to encourage new generations of small factory owners. Housing units like the Ota Techno Core follow the same structure of traditional urban workshops, with a machine shop at ground level and housing on the upper floors [Fig. 14.1]. However, the design of each workshop integrates the extensive electricity and ventilation systems required to house modern machinery and are soundproofed to minimize noise pollution [Fig 14.2]. In doing so, new urban workshops are more discreet than their impromptu counterparts and are more appealing to new generations of machinists. These government and commercially sponsored urban workshops now comprise the additional 1000 small factory operations that have arisen in Ota Ward since 2010. The resurgence of urban machining clusters within a post-industrial city like Tokyo indicates the potential of collaborative and complementary manufacturing communities, not as a production powerhouse, but instead a launchpad for high tech enterprises and technological innovation.


  1. Eriksen, Marcus, Laurent CM Lebreton, Henry S. Carson, Martin Thiel, Charles J. Moore, Jose C. Borerro, Francois Galgani, Peter G. Ryan, and Julia Reisser. "Plastic pollution in the world's oceans: more than 5 trillion plastic pieces weighing over 250,000 tons afloat at sea." PloS one 9, no. 12 (2014): e111913.
  2. Jambeck, Jenna R., Roland Geyer, Chris Wilcox, Theodore R. Siegler, Miriam Perryman, Anthony Andrady, Ramani Narayan, and Kara Lavender Law. "Plastic waste inputs from land into the ocean." Science 347, no. 6223 (2015): 768-771.
  3. Law, Kara Lavender, Skye E. Morét-Ferguson, Deborah S. Goodwin, Erik R. Zettler, Emelia DeForce, Tobias Kukulka, and Giora Proskurowski. "Distribution of surface plastic debris in the eastern Pacific Ocean from an 11-year data set." Environmental science & technology 48, no. 9 (2014): 4732-4738.
  4. Lebreton, LC-M., S. D. Greer, and Jose Carlos Borrero. "Numerical modelling of floating debris in the world’s oceans." Marine pollution bulletin 64, no. 3 (2012): 653-661.
  5. Van Sebille, Erik, Chris Wilcox, Laurent Lebreton, Nikolai Maximenko, Britta Denise Hardesty, Jan A. Van Franeker, Marcus Eriksen, David Siegel, Francois Galgani, and Kara Lavender Law. "A global inventory of small floating plastic debris." Environmental Research Letters 10, no. 12 (2015): 124006.
  6. Moore, Charles J., Shelly L. Moore, Molly K. Leecaster, and Stephen B. Weisberg. "A comparison of plastic and plankton in the North Pacific central gyre." Marine pollution bulletin 42, no. 12 (2001): 1297-1300.
  7. Borrelle, Stephanie B., Jeremy Ringma, Kara Lavender Law, Cole C. Monnahan, Laurent Lebreton, Alexis McGivern, Erin Murphy et al. "Predicted growth in plastic waste exceeds efforts to mitigate plastic pollution." Science 369, no. 6510 (2020): 1515-1518.
  8. Lebreton, Laurent CM, Joost Van Der Zwet, Jan-Willem Damsteeg, Boyan Slat, Anthony Andrady, and Julia Reisser. "River plastic emissions to the world’s oceans." Nature communications 8 (2017): 15611.
  9. Reisser, J., B. Slat, K. Noble, K. du Plessis, M. Epp, M. Proietti, J. de Sonneville, T. Becker, and C. Pattiaratchi. "The vertical distribution of buoyant plastics at sea." Biogeosciences Discussions 11, no. 11 (2014).
  10. Dommergues, Bénédicte, Roberto Brambini, René Mettler, Zaki Abiza, and Bruno Sainte-Rose. "Hydrodynamics and capture efficiency of plastic cleanup booms: Part II—2D Vertical capture efficiency and CFD validation." In International Conference on Offshore Mechanics and Arctic Engineering, vol. 57649, p. V002T08A025. American Society of Mechanical Engineers, 2017.
  11. Dommergues, Bénédicte, Roberto Brambini, René Mettler, Zaki Abiza, and Bruno Sainte-Rose. "Hydrodynamics and capture efficiency of plastic cleanup booms: Part II—2D Vertical capture efficiency and CFD validation." In International Conference on Offshore Mechanics and Arctic Engineering, vol. 57649, p. V002T08A025. American Society of Mechanical Engineers, 2017.
  12. Slat, Boyan. How the oceans can clean themselves: A feasibility study. Ocean Cleanup, 2014.
  13. Thevenon, Florian, Chris Carroll, and Joao Sousa. "Plastic debris in the ocean: the characterization of marine plastics and their environmental impacts, situation analysis report." Gland, Switzerland: IUCN 52 (2014).
  14. Boucher, Julien, and Damien Friot. Primary microplastics in the oceans: a global evaluation of sources. Gland, Switzerland: IUCN, 2017.
  15. Liboiron, Max. "Redefining pollution and action: The matter of plastics." Journal of material culture 21, no. 1 (2016): 87-110.
  16. Verma, Rinku, K. S. Vinoda, M. Papireddy, and A. N. S. Gowda. "Toxic pollutants from plastic waste-a review." Procedia Environ. Sci 35 (2016): 701-708.
  17. Van Emmerik, "Seine plastic debris transport ten-folded during increased river discharge." Frontiers in Marine Science 6 (2019): 642.
  18. Lechner, "The Danube so colourful: a potpourri of plastic litter outnumbers fish larvae in Europe's second largest river." Environmental pollution 188 (2014): 177-181.
  19. Van Emmerik, Tim, and Anna Schwarz. "Plastic debris in rivers." Wiley Interdisciplinary Reviews: Water 7, no. 1 (2020): e1398.
  20. Castro‐Jiménez, J., González‐Fernández, D., Fornier, M., Schmidt, N., & Sempere, R. (2019). Macro‐litter in surface waters from the Rhone River: Plastic pollution and loading to the NW Mediterranean Sea. Marine Pollution Bulletin, 146, 60–66.
  21. Jørgensen, Finn Arne. “Chapter 7, Plastic Futures.” Essay. In Recycling, 101–18. Cambridge, MA: The MIT Press, 2019. 
  22. Japan Environmental Sanitation Center. "Solid waste management and recycling technology of Japan: toward a sustainable society." (2012).
  23. “Marine Plastics.” IUCN, December 5, 2018.
  24. Ritchie, Hannah, and Max Roser. “Plastic Pollution.” Our World in Data, September 1, 2018. 
  25. EPA Alumni Association. “Waste Management, a Half Century of Progress.” EPA Alumni, April 2020. 
  26. “National Overview: Facts and Figures on Materials, Wastes and Recycling.” EPA. Environmental Protection Agency, November 10, 2020. 
  27. “Sustainable Materials Management: Non-Hazardous Materials and Waste Management Hierarchy.” EPA. Environmental Protection Agency, August 10, 2017. 
  28. “Plastics: Material-Specific Data.” EPA. Environmental Protection Agency, September 10, 2020. Plastics: The History of an Ecological Crisis
  29. Rosane, Olivia. “Plastics: The History of an Ecological Crisis.” EcoWatch. EcoWatch, December 18, 2019.
  30. “'Plummeting' Virgin PET Price Threatens Recycling.” Aclima. Accessed December 22, 2020.
  31. Miller, ByRandy. “1, 2, 3, 4, 5, 6, 7: Plastics Recycling By the Numbers.” Miller Recycling, April 14, 2019. 
  32. The Associated Press. “California's Largest Recycling Business Closes, 750 Laid Off.” ABC News. ABC News Network, August 5, 2019. 
  33. Scher,Denny, “How Colorants Affect Plastic Characteristics.” ManufacturingTomorrow. Accessed December 22, 2020. 
  34. “Recycling Plastics – Resource Efficiency with an Optimized Sorting Method.” YouTube. VDI Zentrum Ressourceneffizienz, September 27, 2018. 
  35. “Dirty Business: What Really Happens to Your Recycling.” YouTube. Skynews, January 29, 2018. 
  36. Sepe, Michael. “Understanding the 'Science' of Color.” Plastics Technology, August 26, 2016. 
  37. Cole, Rob. “MRFs Look to the Future.” Resource Magazine, December 11, 2019. 
  38. “Curbside Recycling NYC: Chicago Curbside Recycling.” Sims Municipal Recycling, 2020. 
  39. Hover. “How China Broke the World's Recycling.” YouTube. Wendover Productions, December 16, 2020.